Publisher：Journal of Luminescence  

Mo co-doped LuGd<inf>2</inf>Al<inf>3</inf>Ga<inf>2</inf>O<inf>12</inf>:Ce,Mo (Mo = 0, 300, 600 ppm) single crystals were grown by the micro-pulling-down method. The optical absorption and X-ray excited luminescence spectra, temperature dependence of photoluminescence decay kinetics, afterglow and thermoluminescence (TL) intensity, and scintillation properties (light yield, LY, and decay time) were investigated. The quenching temperature of 355 K was determined from temperature-dependent photoluminescence decay kinetics in the temperature range of 77–487 K under excitation in the 4f - 5d<inf>1</inf> absorption band of the Ce³⁺ ions. Under excitation of 662 keV γ rays, the LuGd<inf>2</inf>Al<inf>3</inf>Ga<inf>2</inf>O<inf>12</inf>:Ce,Mo600 sample showed high LY value of 32,900 photons/MeV, energy resolution of 7.6 %, and scintillation decay time of 119 ns (38 %) + 475 ns (62 %). The lower LY value together with higher contribution of slower scintillation decay component among the samples studied was observed for LuGd<inf>2</inf>Al<inf>3</inf>Ga<inf>2</inf>O<inf>12</inf>:Ce,Mo300 sample, consistently with its higher afterglow intensity and longer de-trapping time of the dominant TL glow peak at 356 K.

DOI： 10.1016/j.jlumin.2026.121737

Scopus

Publisher：Journal of the Electrochemical Society  

In this study, we examined the corrosion resistance of Ru<inf>57</inf>Mo<inf>14.25</inf>W<inf>23.75</inf>Fe<inf>5</inf>, Ru<inf>54</inf>Mo<inf>13.5</inf>W<inf>22.5</inf>Fe<inf>10</inf>, and Ru<inf>48</inf>Mo<inf>12</inf>W<inf>20</inf>Fe<inf>20</inf> alloys in inorganic acids. The alloys were fabricated using the dewetting micro-pulling-down and plasma-melt stamping methods. Immersion tests in H<inf>2</inf>SO<inf>4</inf> at 300 °C for 24 h indicated that Ru-Mo-W-Fe alloys exhibit better corrosion resistance (<0.17 mm y⁻¹), compared to conventional corrosion-resistant materials (>10 mm y⁻¹). Immersion tests at 25 °C in 5% HCl for 72 h and at 100 °C in 50% HF for 24 h also indicated that Ru-Mo-W-Fe alloys are highly corrosion resistant. Electrochemical tests in 1 M HCl and 1 M H<inf>2</inf>SO<inf>4</inf> revealed an increase in the anodic current and the formation of a low charge transfer resistance passive layer corresponding to alloying Fe. XPS analysis revealed that the primary corrosion product formed during polarization of Ru-Mo-W-Fe alloys in 1 M H<inf>2</inf>SO<inf>4</inf> was WO<inf>3</inf>. Notably, WO<inf>3</inf> is kept passivated on pure W during the corrosion in H<inf>2</inf>SO<inf>4</inf>; however, it is not kept passivated when present on Ru-Mo-W-Fe alloys.

DOI： 10.1149/1945-7111/ae4cd0

Open Access

Scopus

Language：English   Publisher：Journal of the American Chemical Society  

Pyrrolamides, defined by a pyrrole-2-carboxamide core, represent a family of natural products produced by Streptomyces species. They exhibit potent yet promiscuous bioactivities, including antimicrobial, antifungal, antiviral, and anticancer effects. The characteristic pyrrole moiety is derived from 4-acetamidopyrrole-2-carboxylate, which was previously proposed to originate most likely from N-acetylglucosamine-1-phosphate. This unusual transformation of a primary metabolite sugar into an aromatic peptide building block is of interest mechanistically; however, the pathway preceding pyrrole formation remains unclear. We herein report the discovery of manlipyrrolamides A–F from Bacillus manliponensis, a new class of pyrrolamides with distinctive structural features. Gene disruption and in vitro assays allowed us to identify the functions of key enzymes in the pyrrole formation pathway. Man17, a nucleotidyltransferase, functions as a gatekeeper that activates the precursor N-acetylglucosamine-1-phosphate, through guanosine diphosphate (GDP) derivatization for subsequent modifications. Man18, a glycosyltransferase-like enzyme, and Man15, a glycoside hydrolase-like enzyme, function as a hydrolase and dehydratase, respectively, forming a pyrrole from a mature GDP-linked sugar. After pyrrole formation, a xanthine dehydrogenase-like enzyme complex is utilized in oxidation to produce carboxylate, distinct from the previously proposed Streptomyces pathway. The pathway-specific enzyme Man15, which is widely distributed in Gram-positive bacteria, is encoded in diverse biosynthetic gene clusters, indicating that this unprecedented transformation is utilized for unknown classes of pyrrolamides. The use of a GDP derivative suggests an orthogonal strategy distinct from that of the canonical UDP-linked sugar pathway. The present study reveals novel sugar skeletal conversion in secondary metabolism, which provides novel insights into bacterial metabolic strategies.

DOI： 10.1021/jacs.5c23027

Open Access

Scopus

PubMed

Publisher：Chemical Physics Letters  

We achieved 61 % ¹H polarization at room temperature and in 0.64 T via Dynamic Nuclear Polarization using photoexcited triplet electrons (Triplet-DNP). Dibenz[ a, h ]anthracene was introduced as a new host for pentacene- d <inf>14</inf>, providing a long spin-lattice relaxation time ( T <inf>1</inf>) exceeding 2 h. Single crystals doped with 0.05 mol% pentacene- d <inf>14</inf> were grown by the Bridgman method and cut to ∼1 mg for experiments. The ¹H polarization buildup and relaxation measurements indicated that paramagnetic relaxation dominates over spin-lattice relaxation. Finally, potential applications of room-temperature hyperpolarization, i.e. , nuclear ordering and radiation-tolerant polarized targets, were discussed.

DOI： 10.1016/j.cplett.2025.142606

Scopus

Publisher：Materials Today Physics  

Novel neutron Li<inf>2</inf>Hf(Br,I)<inf>6</inf> scintillators were developed, and their luminescence and scintillation properties were investigated both experimentally and via density functional theory calculations. The development of conventional neutron scintillators has been dominated by materials with emission wavelengths in the range of 400–500 nm that have wavelength sensitivity of photomultiplier tubes (PMTs). However, with the recent emergence of detectors having higher quantum efficiencies than PMTs, such as Si-based photodetectors, there is a need for neutron scintillators with red-to-near-infrared (red/NIR) emission wavelengths that match the wavelength sensitivity of these detectors. Therefore, this study demonstrates that Li<inf>2</inf>Hf(Br,I)<inf>6</inf> exhibits self-trapped exciton emission under both X-ray and thermal neutron irradiation, with an emission peak at approximately 650 nm, which is 100–200 nm longer than the corresponding peak wavelength of conventional neutron scintillators. The emission wavelength of Li<inf>2</inf>Hf(Br,I)<inf>6</inf> matches the wavelength sensitivity of Si-APD. In addition, Li<inf>2</inf>HfBr<inf>4</inf>I<inf>2</inf> is the first neutron scintillator to combine emission in the red/NIR region with a high light output of approximately 40,000 photons per thermal neutron, which is six to seven times that observed in commercial Ce:Li-glass (GS20). Furthermore, the pulse shape discrimination (PSD) Figure of Merit (FOM) was found to be 2.47, indicating excellent neutron/gamma-ray discrimination capability. This study opens a new avenue for both red/NIR emission and high-light-output neutron scintillators.

DOI： 10.1016/j.mtphys.2025.101997

Open Access

Scopus

Language：English   Publisher：The Ceramic Society of Japan  

<p>Zero-dimensional (0D) metal halide scintillators have attracted considerable attention owing to their exceptional emission properties derived from strongly localized self-trapped excitons. In this paper, we report the development of a novel thermal neutron scintillator—Na₂₋<i>_x</i>Li<i>_x</i>HfI₆ (0 ≤ <i>x</i> ≤ 2)—achieved by strategically substituting lithium for the Na of the 0D Na₂HfI₆ host. The Na₂HfI₆ host material has a 0D structure with an [HfI₆]²⁻ octahedral unit, exhibiting broad red-to-near-infrared (NIR) emission with a large stokes shift, driven by strong electron–phonon coupling (<i>S</i> = 56.7) and high exciton binding energy (<i>E</i>_b = 200 meV). Density functional theory calculations revealed that the A site cations (Na⁺ and Li⁺) did not contribute to the valence or conduction band edges. This indicated that the fundamental electronic structure was preserved upon Li substitution; consequently, the Li-alloyed Na₂₋<i>_x</i>Li<i>_x</i>HfI₆ also exhibited the characteristic broad red-to-NIR emission. Remarkably, the Na_1.5Li_0.5HfI₆ crystal demonstrated a light yield of 37,000 ph./n_th under thermal neutron irradiation, approximately six times higher than that of the standard ⁶Li glass scintillator (GS20). With the fast decay time (650 ns) as red/NIR emission, high light output, and red/NIR emission wavelength, Na₂₋<i>_x</i>Li<i>_x</i>HfI₆ offers a robust and high-performance alternative material to conventional scintillators.</p>

DOI： 10.2109/jcersj2.25178

Open Access

CiNii Research

Publisher：IEEE Transactions on Nuclear Science  

Tl⁺-doped Cs3Cu2I5 (Tl:CCI) scintillator is reported to have a light output of 98,200 photons/MeV and energy resolution of 3.3% (FWHM, 662 keV), while the energy resolution is expected to be improved due to high light output compared to other bright scintillators such as Ce:LaBr3 with an FWHM energy resolution of 3.0% at 662 keV and light output of around 60,000 photons/MeV. The energy resolution is related to nonproportional response (NPR), and NPR and energy resolution for Tl:NaI was improved by co-doping with Sr²⁺ and Ca²⁺. Therefore, we grew Tl:CCI and Sr²⁺ co-doped Tl:CCI (Tl,Sr:CCI) crystals by the vertical Bridgman-Stockbarger method to investigate the Sr²⁺ co-doping effect on the scintillation properties. The result shows the NPR was improved with Sr²⁺ co-doping, and the observed energy resolution was improved; Tl:CCI, 0.1 and 0.5% Sr-codoped Tl:CCI had energy resolutions of 4.9±0.1, 4.5±0.1 and 4.3±0.1% (FWHM, 662 keV), respectively. In addition, their intrinsic energy resolutions (FWHM) at 662 keV were estimated to be 2.1±0.2, 1.1±0.2 and 1.0±0.2%, respectively, so that Sr²⁺ co-doping effect for the energy resolution was observed.

DOI： 10.1109/TNS.2025.3649272

Scopus

Publisher：Proceedings of Science  

MeV gamma-ray astronomy remains relatively underexplored, despite extensive worldwide efforts to investigate this crucial energy range. To address this challenge, we have demonstrated the high-performance capabilities of an electron-tracking Compton camera (ETCC) during the Sub-MeV/MeV gamma-ray Imaging Loaded-on-balloon Experiment (SMILE) missions. The ETCC employs a gaseous time-projection chamber (TPC) as the primary scatterer, surrounded by pixelated scintillator arrays (PSAs) that function as absorbers. The gas TPC measures the momentum vector of the recoil electron, while the PSAs simultaneously determine the energy of the scattered gamma ray. This capability enables a bijective reconstruction of both the direction and energy of the incident gamma ray, which enhances the sensitivity compared to classical Compton reconstruction that constrains the incident direction only by a circular region. The SMILE-2+ experiment, which consisted of a 26-hour balloon flight over Australia, successfully detected the Crab Nebula and Galactic diffuse emissions around the Galactic Center at a significance level exceeding 4σ. Following this achievement, we have initiated the successor project, SMILE-3, to enable a more detailed investigation of diffuse emissions. The detector design has been upgraded to achieve a larger effective area and a wider dynamic range, thereby increasing photon collection power. The first flight for SMILE-3 is currently planned for early 2027. In this paper, we present an overview of the SMILE-3 experiment and report the current status of our R&D efforts.

DOI： 10.22323/1.501.0777

Open Access

Scopus

Publisher：Proceedings of Science  

MeV gamma-ray observations are a probe for uncovering various physical phenomena, such as the search for dark matter and primordial black holes, and the study of the nucleosynthesis in the Universe. To achieve high sensitivity in this band, we are developing an electron-tracking Compton camera (ETCC), which combines a gaseous time projection chamber (TPC) and pixelated GSO(Ce) scintillator arrays (PSAs). The ETCC tracks recoil electrons in the TPC and reconstructs Compton events to uniquely determine gamma-ray arrival directions. We are now planning the Sub-MeV/MeV gamma-ray Imaging Loaded-on-balloon Experiment 3 (SMILE-3), which will use an upgraded ETCC from the previous balloon experiment, SMILE-2+, with improved dynamic range and effective area. The first one-day flight of SMILE-3 is scheduled for spring 2027 in Australia” The ETCC has background events originating from radioactive isotopes contained in the GSO(Ce) scintillators. Therefore, we measured the intrinsic background of all GSO(Ce) scintillators to be used in SMILE-3 and investigated their properties to evaluate the feasibility of selecting low-background scintillators.

DOI： 10.22323/1.501.0690

Open Access

Scopus

Publisher：Journal of Luminescence  

Alkaline earth hafnate perovskite is a promising inorganic scintillator due to its high density and high stopping power; however, its high melting point and phase transitions at elevated temperatures make its crystal growth difficult. We apply chemical vapor deposition method to prepare Ce³⁺-doped CaHfO<inf>3</inf> (Ce³⁺:CaHfO<inf>3</inf>) thick films on the SrTiO<inf>3</inf>, YAlO<inf>3</inf>, and MgO substrates. Ce³⁺:CaHfO<inf>3</inf> thick films were epitaxially grown on each substrate with deposition rates of 44–77 μm h⁻¹. The luminescence spectra of the films at the excitation wavelength of 340 nm showed peaks at 423 nm and 463 nm, which were attributed to the Ce³⁺ 5d → ²F<inf>5/2</inf> and 5d → ²F<inf>7/2</inf> transitions, respectively. The scintillation light yield of the Ce³⁺:CaHfO<inf>3</inf> thick film grown on the MgO substrate was 2900 photons per 5.5 MeV with fast decay constant of 32.1 ns.

DOI： 10.1016/j.jlumin.2025.121568

Open Access

Scopus

Language：English   Publisher：Scientific Reports  

A high-performance Ce³⁺-doped (Gd, Tb)<inf>3</inf>(Ga, Al)<inf>5</inf>O<inf>12</inf> (GTAGG: Ce) single crystal was engineered and characterized, demonstrating a high application potential for advanced X-ray imaging. A transparent 1-inch diameter single crystal was grown using the Czochralski method, demonstrating a significant advancement in large-scale scintillator production. Comprehensive characterization using X-ray diffraction and electron probe micro-analysis confirmed the crystal’s structural integrity. Photoluminescence and radioluminescence spectroscopy demonstrated efficient bidirectional energy transfer between Ce³⁺ and Tb³⁺ ions, a critical mechanism enhancing the performance of the scintillator. X-ray imaging tests were performed using crystals with a thickness of 100 μm at the Aichi Synchrotron Radiation Center. Comparison with the industry-standard LuAG: Ce scintillator showed that the GTAGG: Ce crystal produced 2.4 times higher light output and achieved a high spatial resolution of 0.85 μm. The results indicated that GTAGG: Ce is suitable for the next generation of high-performance X-ray imaging detectors in scientific and medical imaging applications.

DOI： 10.1038/s41598-025-96031-5

Open Access

Scopus

PubMed

Language：English   Publisher：Nature Communications  

Myelodysplastic syndrome (MDS) originates from hematopoietic stem cell (HSC) clones with acquired gene mutations. However, the molecular characteristics of MDS stem cells remain poorly understood. Here, we show that the chromatin accessibility profiles of MDS stem cells more accurately reflect disease status than those of progenitor cells and reveal the process of stem cell alterations during disease progression. Characterization of differentially accessible regions (DARs) shows that MDS stem cells acquire progenitor-like chromatin accessibility during disease progression, leading to disruption of the normal stem-progenitor hierarchy. Profiling of transcription factor-binding motifs at DARs further uncovers precocious activation of myeloid transcriptional networks in MDS stem cells, with a concurrent loss of HSC-associated regulatory programs. In particular, increased chromatin accessibility at CEBP target sites represents the myeloid reprogramming status of MDS stem cells. Newly developed “progenitor scores” based on chromatin accessibility stratify disease status and correlate well with prognosis. These findings indicate that chromatin landscapes of MDS stem cells define their cell-autonomous behavior and contribute to disease progression.

DOI： 10.1038/s41467-025-65753-5

Open Access

Scopus

PubMed

Language：English   Publisher：Leukemia Research  

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) provides curative outcomes for chronic myelomonocytic leukemia (CMML). We conducted a retrospective study to clarify the protective impact of acute and chronic graft-versus-host disease (aGVHD and cGVHD) on relapse by transplant procedures in 314 CMML patients. Interaction effects of conditioning intensity were observed with aGVHD (P<inf>interaction</inf>=0.181) and cGVHD (P<inf>interaction</inf>=0.256) for the cumulative incidence of relapse (CIR), whereas interaction effects of donor type were not detected with GVHD. In patients with the myeloablative conditioning regimens, the multivariate analysis showed that the development of aGVHD was not associated with overall survival (OS). The development of limited cGVHD correlated with better OS (HR [95 % CI], 0.34 [0.14–0.81]; P = 0.015); and that of extensive cGVHD correlated with better OS (HR, 0.44 [0.21–0.91]; P = 0.026) and lower CIR (HR, 0.28 [0.08–0.94]; P = 0.040). In patients with the reduced-intensity conditioning regimens, the development of grade I-II aGVHD correlated with better OS (HR, 0.39 [0.20–0.76]; P = 0.005) and lower CIR (HR, 0.30 [0.13–0.70]; P = 0.006). The development of extensive cGVHD correlated with better OS (HR, 0.44 [0.20–0.96]; P = 0.039). The present results suggest that the type and severity of GVHD mediating graft-versus-leukemia effects against relapse were influenced by conditioning intensity in CMML patients.

DOI： 10.1016/j.leukres.2025.108134

Scopus

PubMed

Publisher：Journal of Luminescence  

Thick film scintillators enhance the spatial resolution of nondestructive X-ray testing. This study investigates thick-film phosphors with dense and uniform microstructure, which smoothly transmit scintillation light, and with columnar-structured phosphors expected to exhibit waveguide effects. We demonstrated the preparation of Yb³⁺:Lu<inf>2</inf>O<inf>3</inf> thick films with both dense and columnar structures using chemical vapor deposition. High deposition temperature and high Lu vaporization temperature yielded dense films, whereas reduced temperatures produced columnar microstructures. Increasing the Yb vaporization temperature increased the lattice constant of the Yb³⁺:Lu<inf>2</inf>O<inf>3</inf> films, suggesting an increase in the Yb concentration in the film. The resulting Yb³⁺:Lu<inf>2</inf>O<inf>3</inf> films exhibited Yb³⁺ charge-transfer luminescence at 300–600 nm and f–f transition emission at 900–1100 nm. For 5.5 MeV-α-particle-excited scintillation, the scintillation light yields of the Yb³⁺:Lu<inf>2</inf>O<inf>3</inf> columnar and dense films with 0.6–9.4 mol%Yb<inf>2</inf>O<inf>3</inf> were ranged from 880 to 1290 photons per 5.5 MeV with a fast decay constant of 1.9–2.2 ns.

DOI： 10.1016/j.jlumin.2025.121589

Open Access

Scopus

Publisher：Materials Advances  

The exposure of luminescent materials to X-ray radiation and high-power laser excitation results in significant heating, leading to thermal quenching and a corresponding reduction in phosphor efficiency. This study aimed to address this limitation by enhancing material efficiency while maintaining high thermal stability. YAG:Ce,Tb transparent ceramics were successfully fabricated via vacuum reactive sintering method, with moderate concentrations of Tb³⁺ ions (1, 5 and 10 at%) codopants. These ceramics exhibited a dense microstructure without micropores, achieving high transparency of 77–80% at 900 nm. The incorporation of Tb³⁺ ions, is evidenced by the systematic increase in lattice constants from 12.608 Å (YAG:Ce) to 12.615 Å (YAG:Ce,Tb10%) in accordance with Vegard's law. The phonon-assisted Ce³⁺ ↔ Tb³⁺ bidirectional resonance mechanism, which facilitated energy transfer between Ce³⁺ and Tb³⁺ ions, was observed. The optimal transfer rate was observed at approximately 480 K. Beyond this temperature, the rate progressively accelerated, leading to accelerated decay times. Notably, YAG:Ce,Tb10% ceramics demonstrated a two-fold increase in radioluminescence intensity compared to uncodoped YAG:Ce ceramics. This substantial improvement in luminescence performance highlights the potential of YAG:Ce,Tb ceramics as highly efficient phosphors for X-ray imaging applications, offering enhanced brightness and energy transfer efficiency under high-temperature operating conditions. The Tb³⁺ codoping also enhanced Ce³⁺ emission, allowing for tuning of the correlated color temperature to a maximum of 6013 K, while maintaining a stable color rendering index of 69–73 and luminous efficacy of ∼123 lm W⁻¹. It was shown that the luminous efficacy was not a constant parameter, but depended on the excitation laser power, initially increasing with power up to 0.5 W and then saturating. These results establish YAG:Ce,Tb transparent ceramics as highly promising materials for white LEDs due to their good thermal stability, tunable optical properties, and enhanced luminescence performance.

DOI： 10.1039/d5ma00464k

Open Access

Scopus

Publisher：Physica Status Solidi B Basic Research  

Corundum-structured Sn-doped indium oxide (rh-ITO) is investigated as a novel transparent conductive oxide. Herein, its gamma-ray tolerance up to a total dose of 77 kGy is examined for potential applications in harsh environments, such as space. The investigations are conducted on rh-ITO with Sn concentrations of 0 and 5 at%. X-ray diffraction 2θ-ω scan analysis reveals that no phase separation occurs due to gamma-ray irradiation. The carrier concentration in undoped rh-In<inf>2</inf>O<inf>3</inf> increases after irradiation, indicating that the gamma rays displace the oxygen atoms and form oxygen defects that generate donors. The high visible light transparency of rh-In<inf>2</inf>O<inf>3</inf> and rh-ITO is maintained after irradiation. This study demonstrates the high stability of rh-ITO to gamma-ray irradiation until 77 kGy dose. This work contributes to the application of rh-ITO as an electrode in high-radiation environments.

DOI： 10.1002/pssb.202400368

Scopus

Publisher：Journal of Astronomical Telescopes Instruments and Systems  

HiZ-GUNDAM is a candidate for JAXA’s competitive medium-class mission program, with its concept approved by ISAS/JAXA in 2018. This proposed satellite aims to play a leading role in time-domain astronomy in the 2030s by pursuing two primary scientific goals: (1) probing the early universe through the detection of high-redshift gamma-ray bursts (GRBs) and (2) enabling the rapid identification of X-ray and optical-near-infrared counterparts of multimessenger sources. To achieve these objectives, HiZ-GUNDAM is equipped with two key instruments. A wide-field X-ray monitor, EAGLE, utilizes a micropore optics array and a focal plane imaging sensor to observe transients across ∼0.5sr in the 0.4 to 4 keV energy range. To follow up on this observation, an optical–near-infrared telescope, MONSTER, features a 30 cm aperture and conducts simultaneous five-band photometry over the 0.5 to 2.5μm wavelength range. It employs a Kösters-type prism for multi-band photometry to follow up on transients detected by the EAGLE. A sun-synchronous dawn–dusk orbit has been selected to ensure thermal stability for the MONSTER. We present a comprehensive overview of the HiZ-GUNDAM mission concept. The mission is expected to make a significant contribution to our understanding of cosmic evolution through observations of high-redshift GRBs, as well as to the identification of the multiwavelength properties of multimessenger sources by enhancing the observational capabilities for transient searches. The specifications and concepts discussed herein are subject to refinement as the mission progresses.

DOI： 10.1117/1.JATIS.11.4.044002

Open Access

Scopus

Publisher：Journal of Anaesthesiology Clinical Pharmacology  

DOI： 10.4103/joacp.joacp_533_24

Open Access

Scopus

Language：English   Publisher：Transplantation and Cellular Therapy  

Although allogeneic hematopoietic stem cell transplantation (SCT) remains a potentially curative treatment option for several myeloid malignancies, despite the fact that the average age at disease onset for myeloid malignancies is approximately 70 years of age, its applicability in elderly patients is challenging. We retrospectively evaluated the outcomes of elderly SCT patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS), using a nationwide Japanese registry database. We analyzed the data of 3609 patients ranging from 65 to 79 years of age with AML or MDS who underwent initial SCT between 2003 and 2022, while focusing on those 70 to 74 (n = 645) and 75 to 79 years old (n = 65). The 2-year overall survival (OS) and relapse-free survival rates for patients aged 65 to 69, 70 to 74, and 75 to 79 years were 40.9%, 38.0%, and 22.7%, and 48.4%, 47.2%, and 18.5%, respectively. Among patients categorized as low-risk at SCT, no significant differences were observed in the cumulative incidence of grade III to IV acute graft-versus-host disease (aGVHD), extensive chronic GVHD (cGVHD), non-relapse mortality, or relapse across all age groups. A multivariate analysis revealed that sex (male), diagnosis (AML), disease status (high-risk), SCT year (2003 to 2007), performance status (2-4), hematopoietic cell transplantation-specific comorbidity index (≥3), development of grade III to IV III–IV aGVHD, and extensive chronic GVHD significantly affected the OS. An older age (75 to 79) and the intensity of conditioning (reduced intensity) were factors indicating a trend toward an adverse prognosis. In these subgroups, significant interactions were observed between OS and SCT years, the time from diagnosis to SCT, and aGVHD. These findings suggest that SCT may be a potential curative option for selected elderly patients up to the mid-70s; however, careful patient selection and vigilant management of aGVHD are crucial factors for improving outcomes.

DOI： 10.1016/j.jtct.2025.06.032

Scopus

PubMed

Publisher：Radiation Measurements  

Cross-sectional images were obtained using photon-counting computed tomography (PCCT) for medical applications, incorporating a silicon photomultiplier (SiPM) and Ce-, Mg- and Al-codoped SrHfO<inf>3</inf> transparent-ceramic scintillator (Mg/Al/Ce:SHO). A maximum counting rate of 8 MHz was achieved with our PCCT system equipped with this scintillator. Enhancing the maximum counting rate is crucial for short-time imaging, and further advancements in counting capability are essential for clinical applications. The Mg/Al/Ce:SHO scintillator, which has a shorter decay time (∼20 ns) and higher density (7.6 g/cm³) compared to the Ce:(Y, Gd)<inf>3</inf>(Al, Ga)<inf>5</inf>O<inf>12</inf> scintillator used in earlier PCCT systems, was prepared via spark plasma sintering and integrated into the PCCT. The maximum counting rate was estimated by varying the intensity of incident X-ray photons using an X-ray tube and applying a non-paralyzable dead-time model, yielding approximately 8 MHz–double the photon-counting capability of our previous system. Additionally, static phantom imaging with iodine and gadolinium contrast agents was performed at X-ray tube current of 0.5, 1.0 and 2.0 mA. The image quality remained consistent within the standard deviation of CT values despite increasing the tube current. These findings suggest that the Mg/Al/Ce:SHO scintillator offers superior potential for clinical PCCT applications compared to conventional systems.

DOI： 10.1016/j.radmeas.2025.107456

Scopus

Publisher：Crystals  

In this study, we developed and characterized novel scintillators with Ce: LiCaAlF<inf>6</inf>–CaF<inf>2</inf>–Li<inf>3</inf>AlF<inf>6</inf> and Ce: CaF<inf>2</inf>–LiF–Li<inf>3</inf>AlF<inf>6</inf> ternary systems for thermal neutron detectors. The eutectics were grown by the vertical Stochbarger-Bridgman (VB) technique, and their constituent phases were identified using powder X-ray diffraction and scanning electron microscopy. Radioluminescence spectra irradiated under an Ag-target X-ray tube and confirmed the 5d-4f and self-trapped exciton luminescence derived from Ce³⁺. Scintillation decay and pulse height measurements were performed using ²⁵²Cf and ⁶⁰Co sources. The Ce: CaF<inf>2</inf>–LiF–Li<inf>3</inf>AlF<inf>6</inf> sample exhibited approximately 5.6 times higher effective neutron sensitivity compared with a Ce: LiCaAlF<inf>6</inf> single crystal. A favorable decrease in the neutron discrimination threshold level (Q<inf>th</inf>) due to reduced γ-ray emission was observed. ⁶Li-enriched Ce: CaF-based scintillators hold potential for nuclear decommissioning applications.

DOI： 10.3390/cryst15090761

Open Access

Scopus

Language：English   Publisher：Kidney International Reports  

DOI： 10.1016/j.ekir.2025.05.015

Open Access

Scopus

PubMed

Language：English   Publisher：Nano Letters  

The exchange bias effect, which causes a shift in the ferromagnetic hysteresis loop due to magnetic coupling with an adjacent antiferromagnetic layer, has been a key area of study for fundamental research and spintronic applications. This effect is known to be static once established through a field cooling procedure and is difficult to manipulate isothermally. Here we present the first room temperature field switching of interlayer magnetic coupling at the metallic heterointerface between a ferromagnet and antiferromaget. Specifically, we demonstrate that the exchange bias can be systematically switched by manipulating the global time-reversal-symmetry-broken antiferromagnetic order of Mn<inf>3</inf>Sn via both magnetic field sweeping and field cooling. Furthermore, we confirm that the magnitude and sign of the interlayer coupling can be tuned by selecting the ferromagnet. These findings provide a novel approach for controlling the magnetic state of ferromagnets and functional antiferromagnets, paving the way for advancing spintronic technologies using antiferromagnets.

DOI： 10.1021/acs.nanolett.5c00988

Scopus

PubMed

Publisher：Japanese Journal of Applied Physics Part 1 Regular Papers and Short Notes and Review Papers  

Accelerator-based boron neutron capture therapy (AB-BNCT) systems that utilize various neutron production methods have been developed in recent years. As the AB-BNCT system is a novel radiation production system, accurately measuring the neutron ambient dose is crucial for evaluating its performance and ensuring its safety. In this study, we designed a neutron detector system capable of measuring the neutron ambient dose H* in a cyclotron-based epithermal neutron source irradiation field using the particle and heavy ion transport code system 3.34 Monte Carlo simulation code. This neutron detector system comprises slow and fast neutron detectors, which are sensitive to energy ranges of 10⁻⁹-10⁻² MeV and 10⁻²-28 MeV, respectively. The response function of this neutron detector system exhibited satisfactory agreement with the conversion coefficients h*, and the dose measurement accuracy was within 6.5%.

DOI： 10.35848/1347-4065/add593

Open Access

Scopus

Publisher：Journal of Instrumentation  

The future satellite HiZ-GUNDAM will be equipped with a wide-field X-ray monitor using Lobster Eye Optics (LEO), covering a wide field of view of ∼ 0.6 steradian in the 0.4-4 keV energy range. LEO, an X-ray optics system, achieves both a wide field of view and high sensitivity by focusing soft X-rays through spherically curved SiO<inf>2</inf> plates with heavy-metal-coated micropores. This design significantly enhances sensitivity by reducing cosmic X-ray background events, outperforming conventional non-focusing detectors. As a prototype, we developed a breadboard frame capable of holding nine LEO segments, aligning them on a single spherical surface to achieve a wide field of view. Given LEO's brittleness, there are concerns about potential damage from launch vehicle vibrations. In addition, the system must be structurally robust, avoiding strong resonances at expected vibration frequencies. To address these concerns, we performed vibration tests simulating launch conditions to assess the structural integrity of the combined LEO and breadboard frame. X-ray performance, particularly angular resolution, was evaluated before and after the tests. The results demonstrate that the system is structurally robust and capable of maintaining imaging performance after simulated rocket launch vibrations.

DOI： 10.1088/1748-0221/20/06/C06044

Scopus

Language：English   Publisher：Cytotherapy  

We evaluated the impact of center volume on outcomes in patients with B-cell acute lymphoblastic leukemia following their second allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our cohort included 299 patients with relapse and 68 patients with graft failure after their first allo-HSCT between 2003 and 2017. Patients were stratified into low- and high-volume groups based on the number of allo-HSCT performed at each center. The primary endpoint was 5-year overall survival (OS) following the second allo-HSCT. In the relapse cohort, the high-volume group demonstrated significantly better 5-year OS (21.1% vs 13.6%, P = 0.0062) and progression-free survival (16.1% vs 10.6%, P = 0.010). Multivariate analysis showed that high-volume group was a favorable factor for OS (hazard ratio [HR]: 0.72, 95% confidence interval [CI]: 0.56–0.94, P = 0.016). This survival benefit was consistent in both Philadelphia chromosome-negative (HR: 0.71, 95% CI: 0.51–0.99, P = 0.042) and positive (HR: 0.61, 95% CI: 0.39–0.95, P = 0.030) subcohorts. In the graft failure cohort, the high-volume group showed a trend toward better 5-year OS (41.6% vs 24.4%, P = 0.098) and lower 5-year nonrelapse mortality (NRM) (55.9% vs 75.6%, P = 0.067). Multivariate analysis confirmed the protective effect of the high-volume group on NRM (HR: 0.55, 95% CI: 0.30–0.99, P = 0.044). Our findings demonstrate that center volume significantly impacts outcomes after the second allo-HSCT regardless of indication, highlighting the need for inter-center collaboration and standardized management strategies for this high-risk population.

DOI： 10.1016/j.jcyt.2025.03.002

Scopus

PubMed

Publisher：Radiation Measurements  

In recent years, intrinsic self-trapped exciton (STE) emission materials have been developed as promising scintillators due to their bright and self-absorption free luminescence. Among these materials, cesium hafnium chloride (Cs<inf>2</inf>HfCl<inf>6</inf>, CHC) has received attention for its high light yield, remarkable energy resolution, high radiation-stopping capability, absence of radioactive background, and low non-proportionality. This study investigated the luminescence and scintillation properties of both the undoped and alkali earth metals (AE)-doped CHC. The findings revealed that undoped and AE-doped CHC exhibited four emission peaks at 368, 383, 435, and 465 nm, corresponding to intrinsic STE emission, defect-related emission, Zr-related emission, and I-related emission, respectively. The corresponding decay time were about 1.5, 5.5, 11, and 2.3 μs. Notably, AE doping did not introduce any new emission centers, as confirmed by photoluminescence and radioluminescence spectra. The light yield and energy resolution for undoped CHC and CHC:AE were measured to be 34,000–37,000 ph/MeV and 3.5–4.1 % at 662 keV, respectively. Although AE doping did not enhance scintillation properties of CHC, this study elucidated several sources of luminescence centers in CHC, providing valuable insights for future optimization of its scintillation properties.

DOI： 10.1016/j.radmeas.2025.107438

Scopus

Language：English   Publisher：ACS Omega  

This study explored the influence of Sc³⁺ ions incorporation on the structural, vibrational, luminescent, and scintillation properties of Pr³⁺-doped Lu<inf>3</inf>(Al, Sc)<inf>2.5</inf>Ga<inf>2.5</inf>O<inf>12</inf> garnet crystals. Addressing the limited research on Sc-admixed and Pr³⁺ doped garnet systems, this work successfully demonstrated the crystallization of garnet crystals from the melt, overcoming the substantial atomic mismatch between Sc and Al while preserving the thermodynamic stability of the garnet phase. Importantly, Sc-admixing enhanced atomic homogeneity and allowed for increased doping concentrations of Pr³⁺ ions, which is crucial for tailoring the functional properties of advanced optical materials. The trap depths ranged from 1.63 eV (deep traps) to 0.22 eV (shallow traps) across all samples, with frequency factors predominantly between 1 × 10⁷ and 1 × 10¹¹ s^-1, consistent with first-order thermoluminescent kinetics. From a materials design perspective, Sc³⁺ ions substitution induced beneficial host lattice disorder, enhancing the emission intensity of 4f¹5d<inf>1</inf>¹ → 4f² interconfigurational and 4f² → 4f² intraconfigurational transitions. This effect highlighted the potential of Sc as a promising substituent for enhancing the luminescence intensity of rare earth elements. Synchrotron radiation experiments provided insights into the impact of Sc on band gap energy and energy transfer efficiency toward Pr³⁺ ions offering new opportunities for engineering scintillators and phosphors with tunable optical properties.

DOI： 10.1021/acsomega.5c01062

Open Access

Scopus

PubMed

Publisher：Journal of Radiation Protection and Research  

Background: At nuclear facilities and decommissioning sites, monitoring radioactivity concentrations in airborne particulates is crucial to prevent worker exposure. To avoid internal exposure, alpha-decay radionuclides must be detected. When monitoring alpha-decay radionuclides in airborne dust, we want to measure the concentration of only artificial radionuclides (e.g., ²³⁸Pu, ²³⁹Pu, ²⁴⁰Pu, ²³⁵U, ²³⁸U, ²⁴¹Am, and ²⁴⁴Cm). The radioactivity concentration must be measured separately for artificial (4.3–5.8 MeV) and natural radionuclides (²¹²Bi, ²¹⁴Po, and ²¹²Po at 6.0, 7.7, and 8.8 MeV, respectively). Materials and Methods: We created response functions for various alpha-ray energies using a radiation simulation toolkit. Utilizing these response functions, we deconvolved the alpha-ray energy spectra measured while collecting dust on filter paper. To ensure the precision of the response function, we prepared a model including the distance between the filter and the detector and the structure of the light shield in detail. Results and Discussion: The deconvolved spectra had three clear peaks at 6.0, 7.7, and 8.8 MeV. These energies were consistent with those of ²¹²Bi, ²¹⁴Po, and ²¹²Po. The deconvolved energy spectra showed that only a few measurements (4.0–5.8 MeV) were included in the energy range due to artificial radionuclides. From these measurements, the decision threshold for artificial radionuclides was determined to be about 1.5×10⁻⁷ Bq/cm³. Conclusion: Our findings demonstrated that we could measure artificial and natural radionuclides separately with the deconvolved alpha-ray energy spectra. Specifically, we were able to monitor artificial radionuclides down to low radioactivity concentrations in 10-minute measurements.

DOI： 10.14407/jrpr.2023.00444

Open Access

Scopus

Publisher：Journal of Luminescence  

Optical thermometry is one of the promising methods of detecting temperature under harsh environments. In this study, for the development of a novel optical thermometer, we focused on Eu-doped (Y, Lu, Sc)<inf>2</inf>O<inf>3</inf> and grew single crystals using the micro-pulling-down method. Crystal growth was performed by systematically changing the ratio of Y to Lu, and the crystalline system and space group were identified to be cubic and Ia–3, respectively, by the powder X-ray diffraction analysis. From the photoluminescence emission spectra, the emission peaks attributed to Eu³⁺ ⁵D<inf>0</inf>–⁷F<inf>1</inf> and ⁵D<inf>1</inf>–⁷F<inf>1</inf> transitions were observed. The temperature dependence of these emission peaks was measured and evaluated using the fluorescence intensity ratio method to estimate the performance as the optical thermometer. It was found that Eu-doped (Y, Lu, Sc)<inf>2</inf>O<inf>3</inf> can be used as the optical thermometer in the temperature range from 430 K to 790 K. The relative sensitivity reached a maximum of 0.22 %K⁻¹ at 760 K.

DOI： 10.1016/j.jlumin.2025.121118

Open Access

Scopus

Language：English   Publisher：American Journal of Hematology  

DOI： 10.1002/ajh.27641

Scopus

PubMed

Publisher：Astrophysical Journal  

The electron antineutrino flux limits are presented for the brightest gamma-ray burst (GRB) of all time, GRB221009A, over a range of 1.8-200 MeV using the Kamioka Liquid Scintillator Antineutrino Detector. Using multiple time windows ranging from minutes to days surrounding the event to search for electron antineutrinos coincident with the GRB, we set an upper limit on the flux under the assumption of several power-law neutrino source spectra, with power-law indices ranging from 1.5 to 3 in steps of 0.5. No excess was observed in any time windows ranging from seconds to days around the event trigger time T<inf>0</inf>. For a power-law index of 2 and a time window of T<inf>0</inf> ± 500 s, a flux upper limit of 2.34 × 10⁹ cm⁻² was calculated. The limits are compared to the results presented by IceCube.

DOI： 10.3847/1538-4357/ad9c36

Open Access

Scopus

Publisher：Journal of Materials Chemistry C  

In recent decades, optical thermometry has gained significant attention due to its promising properties, such as non-contact measurement, temperature mapping and immunity to electromagnetic interference. It overcomes the limitations of conventional temperature measurement methods and offers additional benefits. However, the widespread adoption of optical thermometry requires an expanded operating temperature range and improved sensitivity. Therefore, in this study, we focused on solid-solution sesquioxides, which are expected not only to enable the growth of single crystals with a cubic structure but also to allow for a wider selection of luminescence centers. We evaluated the applicability of (Lu, Y, Sc)<inf>2</inf>O<inf>3</inf> single crystals doped with Pr³⁺ and Tb³⁺, which exhibit different temperature dependent behaviors, for optical thermometry. The optical temperature sensing properties evaluated using the fluorescence lifetime method revealed a maximal relative sensitivity of 1.53% K⁻¹ in the temperature range of 78-790 K for Pr³⁺, Tb³⁺:(Lu, Y, Sc)<inf>2</inf>O<inf>3</inf>. These results suggest that (Lu, Y, Sc)<inf>2</inf>O<inf>3</inf> co-doped with Pr³⁺ and Tb³⁺ is a promising candidate for optical thermometry.

DOI： 10.1039/d5tc00156k

Open Access

Scopus

Publisher：Crystals  

Ce-doped Lu<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> has a high density, high luminescence efficiency even at high temperatures, and a high effective atomic number, making it a promising candidate for use as a radiation detector in medical devices and resource exploration equipment. In this study, we grow and characterize Pr³⁺ and Ce³⁺-doped Lu<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> single crystals by systematically varying the Ce³⁺ to Pr³⁺ ratio to further improve scintillation properties. The optical characterization results show a bidirectional energy transfer: from the Pr³⁺ 5d levels to the Ce³⁺ 5d levels and from the Ce³⁺ 5d levels to the Pr³⁺ 4f levels. Consistently with this result, the PL decay time of emission from the Pr³⁺ 5d–4f transition tends to become faster as the Ce³⁺/Pr³⁺ ratio increases, due to the energy transfer from the Pr³⁺ 5d levels to the Ce³⁺ 5d levels. Additionally, (Ce<inf>0.0022</inf> Pr<inf>0.0016</inf> Lu<inf>0.9962</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> exhibits a high light yield comparable to Ce-doped Lu<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> and a slightly faster decay time than Ce-doped Lu<inf>2</inf>Si<inf>2</inf>O<inf>7</inf>.

DOI： 10.3390/cryst15030202

Open Access

Scopus

Publisher：Radiation Measurements  

The effects of different types of radiation on a high-resolution alpha imager developed using an electron multiplying charge-coupled device (EMCCD) camera were investigated. This imager was originally developed to visualize alpha particles from Pu oxide particles at decommissioning sites. Other types of radiation such as beta particles, gamma rays, and neutrons are also present. The purpose of this study is to investigate the effects of these background radiations on the imager and to develop a method to discriminate between alpha particles and other types of radiation. When measuring gamma rays, and neutrons, the sensor of the EMCCD camera generated high intensity signals due to gamma rays and neutrons. These radiations were identified by image processing. The image values were binarized and the findContours function for detecting edges in an image was applied to count the number of alpha particle spots. The results showed that alpha and gamma (neutron) radiation can be discriminated by using differences in intensity. This method will be useful for visualizing alpha particles at decommissioning sites.

DOI： 10.1016/j.radmeas.2024.107371

Scopus

Publisher：Cytotherapy  

Background aims: Allogeneic hematopoietic stem cell transplantation (HSCT) improves outcomes for myelodysplastic syndrome (MDS) patients, but relapse rates remain high, and postrelapse treatment options are limited. Therefore, this study aimed to identify the factors contributing to the response to donor lymphocyte infusion (DLI) in relapsed MDS patients post-HSCT. Methods: This study included 107 patients with relapsed and DLI-treated MDS who underwent their first HSCT between 2002 and 2022 and were registered in the Transplant Registry Unified Program. Univariate and multivariate survival analyses were conducted using log-rank tests and Cox proportional hazards models. Overall survival (OS) and response rates to DLI were also analyzed. Results: The 1-year OS was 30.0% and univariate analysis identified poor prognostic factors: age ≥58 years (P = 0.003), complex karyotype (P = 0.026), hematologic relapse (P = 0.026) and early relapse (P = 0.004). Azacitidine plus DLI also improved prognosis (P < 0.001). Multivariate analysis confirmed age ≥58 years, hematologic relapse, and early relapse as poor prognostic factors. The adjusted OS for patients aged ≥58 years who relapsed <110 days post-transplant showed that the 1-year OS in patients with cytogenetic/molecular relapse was 43.6%, compared to 9.4% for those with hematologic relapse. Acute graft-versus-host disease (GVHD) occurred in 62.3% of patients, and chronic GVHD in 30.8%, with manageable outcomes. Conclusions: DLI may improve OS in younger patients, those with cytogenetic/molecular relapse, and those with late relapse. Despite the risk of GVHD, its impact on prognosis is minimal. Given the limited treatment options, DLI should be considered for relapsed MDS patients post-HSCT.

DOI： 10.1016/j.jcyt.2024.09.006

Scopus

Language：English   Publisher：Case Reports in Oncology  

Abstract – Introduction: Enfortumab vedotin (EV) has been approved for the treatment of many types of cancer, and its use is still expanding. It is an essential drug used as a standard treatment for advanced and metastatic urothelial carcinoma but is known to cause various adverse events (AEs). Case Presentation: We report a patient with metastatic urothelial carcinoma who experienced multiple AEs associated with diabetic ketoacidosis (DKA) during EV treatment. The onset of DKA during EV treatment has been reported to be associated with poor prognosis. Although strict management was required in the intensive care unit, we were able to save the patient’s life. Conclusion: Although the detailed mechanism that induced insulin resistance remains unclear, the patient required high-dose insulin because of a marked increase in insulin resistance. If hyperglycemia is observed during EV therapy, DKA may lead to the occurrence of serious AEs. We report on the pathogenesis and management of drug-induced DKA caused by EV based on our case and a literature review.

DOI： 10.1159/000545957

Open Access

Scopus

PubMed

Language：English   Publisher：Supportive Care in Cancer  

Purpose: The benefit of patient-reported outcomes (PRO) in routine oncology practice is increasingly recognized. This study aimed to develop a team-based monitoring and intervention system using electronic PRO (ePRO) and to evaluate its impact at an outpatient oncology clinic. Methods: Patients receiving chemotherapy at our department were eligible for this study. Those who had access to a smartphone or tablet (Bring Your Own Device [BYOD]) and consented participated, and reported 28 symptoms weekly via 3H P-guardian downloaded on their BYOD. E-mail alerts were sent to attending healthcare providers when participants reported at least grade 3 severity for any of nine symptoms (decreased appetite, nausea, vomiting, diarrhea, shortness of breath, pain, insomnia, fatigue, and sadness), which prompted interventions. Comparisons of overall survival (OS), emergency room visits, and hospitalizations were conducted using propensity scores. Results: Among 203 patients who received chemotherapy from September 2021 to August 2023, 77 participated in ePRO monitoring. The overall response rate was 55% (1991 valid responses out of a total of 3597 expected time points), and the median individual response rate was 66% (range, 0–100%). Of 1991 valid responses, 250 (13%) prompted alerts, and most interventions were initiated by making telephone calls. OS and other clinical outcomes were better in ePRO participants compared with non-participants, but these outcomes did not differ significantly between the ePRO and pre-ePRO eras. Conclusions: It was feasible to develop a multi-professional team-based monitoring and intervention system using ePRO at a single-center outpatient oncology clinic. Our results indicate that weekly monitoring of ePRO, along with corresponding interventions, may benefit patients receiving chemotherapy.

DOI： 10.1007/s00520-024-09062-5

Scopus

PubMed

Publisher：Optical Materials  

Luminescence and scintillation properties of Mo co-doped Y<inf>1.5</inf>Gd<inf>1.5</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mo (Mo = 0, 300, 600 ppm) multicomponent garnet crystals grown by the micro-pulling-down method were investigated. To investigate temperature stability, temperature dependence of photoluminescence decay time was measured from 77 to 487 K and thermal activation energy was determined. Y<inf>1.5</inf>Gd<inf>1.5</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mo (300, 600 ppm) samples showed faster scintillation decay time with a similar LY value compared to Mo-free Y<inf>1.5</inf>Gd<inf>1.5</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce one. Y<inf>1.5</inf>Gd<inf>1.5</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mo (600 ppm) showed a light yield value of 34,300 photons/MeV along with fast scintillation decay times of 45.2 ns (55 %) +153 ns (45 %) and time resolution of 313 ps. Radioluminescence and afterglow signal were also measured at RT and discussed.

DOI： 10.1016/j.optmat.2024.116494

Scopus

Publisher：Journal of Nuclear Science and Technology  

Nuclear decommissioning is crucial as nuclear facilities become old. This trend has recently accelerated, particularly following the accident at Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Holdings. New nuclear decommissioning technologies are required to improve safety, save time, and reduce costs. An example is γ-ray/X-ray (radiation photon) spectroscopy, which provides information on the types of radionuclides with radiation photon emissions. A feasibility study of radiation photon spectroscopy in conjunction with reactor dosimetry in a control rod guide tube positioned at the center of Fugen (a prototype advanced thermal reactor under decommissioning) was conducted. Fugen is a prototype advanced thermal reactor with 165 MWe electric power generation that is being decommissioned. The dose rates measured in a control rod guide tube positioned at the center of the reactor of FUGEN were 4.1–9.1 Gy/h. The dose rate considerably increased at a position close to a tank that contained ⁶⁰Co caused by the radioactivation of stainless steel. Radiation photon spectroscopy was performed without radiation shielding, identifying ⁶⁰Co with an energy resolution better than 5.4% at 1333 keV and ⁹⁴Nb with an energy resolution better than 5.9% at 871 keV.

DOI： 10.1080/00223131.2024.2417786

Open Access

Scopus

Publisher：Proceedings of the IAHR World Congress  

In recent years, more accurate flood forecasting information has been needed to contribute to flood prevention activities and damage minimization in the event of flood disasters that exceed the planned scale. However, many of the flood forecasting systems used in Japan are designed to target summer floods caused by rainfall and cannot be applied to snowmelt floods in early spring. For this reason, research is being conducted to enable year-round flood forecasting, including snowmelt floods. In this paper, we apply AI technology to snow distribution estimation to ensure the accuracy of snowmelt flood forecasting and demonstrate its practicality through verification results.

Scopus

Language：Japanese   Publisher：The Japanese Association for Crystal Growth  

<p>  Real dose monitors under the high dose-rate condition are required to remove the debris in the Fukushima Daiichi Nuclear Power Plant as the decommissioning step, and I have proposed a dose-rate monitor consisting of a scintillator, optical fiber and photo detector. To realize such monitor, scintillation materials are required to have the long-emission-wavelength (550 - 1000 nm) and high light output. From this reason, several novel materials such as Cs₂HfI₆ and Rb₂HfI₆ for gamma-ray detection have been developed, and Li₂HfBr₆ had sensitive to both gamma ray and neutrons. These scintillators had an emission wavelengths of 600 to 750 nm, and I review the detail of such red and infrared emitting scintillator.</p>

DOI： 10.19009/jjacg.52-2-03

Open Access

CiNii Research

Publisher：Journal of Alloys and Compounds  

The development of scintillators with co-doping mechanisms has received significant attention due to the resulting enhancements in luminescence and scintillation properties. Scintillators such as Ce-doped (Gd,Tb)<inf>3</inf>(Al,Ga)<inf>5</inf>O<inf>12</inf> have been recognized for their improved performance, attributed to the effective energy transfer between Ce³⁺ and Tb³⁺ ions. Nevertheless, the presence of Gd³⁺ introduced complexities, as its absorption lines strongly overlap with those of Tb³⁺, thus masking the details of mechanisms of the Tb³⁺↔Ce³⁺ energy transfer. This study endeavored to elucidate this mechanism by comparing the luminescence characteristics of Ce,Tb co-doped Y<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> (YAGG) and Gd<inf>3</inf>A<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> (GAGG) single crystals. Through detailed photoluminescence spectral analysis, it was discerned that GAGG exhibited a more robust Tb³⁺↔Ce³⁺ energy transfer, as evidenced by a marked extension in the decay time of Ce³⁺ luminescence. Furthermore, GAGG demonstrated superior integrated radioluminescence intensity across all compositions which is a result of efficient energy transfer from Gd³⁺ to the luminescence centers. Additionally, comparative thermally stimulated luminescence glow curves, revealed distinctive spectral features between YAGG and GAGG, underscoring the complexity of their luminescence mechanisms. This comparative study not only augmented our comprehension of the intricate energy transfer processes in Ce, Tb co-doped garnet scintillators but also underscored the potential for tailored scintillator development through strategic ion co-doping.

DOI： 10.1016/j.jallcom.2024.176550

Open Access

Scopus

Publisher：Journal of Alloys and Compounds  

The luminescence, scintillation and photoconversion properties of Ce³⁺-doped Lu<inf>0.6</inf>Gd<inf>2.4</inf>(Al<inf>5-x</inf>Sc<inf>x</inf>)O<inf>12</inf> (x = 1.2, 1.5, 2) garnet crystals grown by micro-pulling-down method were investigated. Increasing Sc³⁺ concentration induced lattice strain and cracking due to ionic radius mismatch. At low Sc³⁺ concentration, the strain caused core-concentrated cracks and radial inhomogeneity. At higher Sc³⁺ concentration, extensive cracking occurred throughout crystals, improving radial homogeneity. With the increase of Sc³⁺ concentration, the Ce³⁺ 5d<inf>1</inf> → 4f luminescence was slightly blue-shifted due to the decrease in crystal field splitting of the 5d levels. At room temperature (RT), the increase of light yield with increasing Sc³⁺ concentration was attributed to the decrease in the bandgap value. Above RT, the decrease of photo- and radio-luminescence for all samples was due to the thermal ionization process. The decrease of radioluminescence at low-temperature regions can be caused by the localization of electrons at intrinsic shallow traps. Photoluminescence measurements disclosed that variations in scandium concentration can effectively modulate the correlated color temperature (CCT), color rendering index (CRI), and luminous efficiency (LE) of these luminescent materials. The incorporation of a micro-perovskite phase in the Lu<inf>0.6</inf>Gd<inf>2.4</inf>(Al<inf>3.8</inf>Sc<inf>1.2</inf>)O<inf>12</inf>:Ce crystal resulted in a notable enhancement of the luminous efficiency, exhibiting a 38 % increase when compared to the sample devoid of micro-inclusions (e.g. x = 2.0).

DOI： 10.1016/j.jallcom.2024.176586

Scopus

Language：English   Publisher：Cytotherapy  

This nationwide study retrospectively examined the center effect on allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult B-cell acute lymphoblastic leukemia. The cohort analyses were separated into Philadelphia chromosome (Ph)-positive and -negative cases. The patients were divided into low- and high-volume groups according to the number of allo-HSCTs at each facility. The primary endpoint was 5-year overall survival (OS). This study included 1156 low-volume and 1329 high-volume Ph-negative and 855 low-volume and 926 high-volume Ph-positive cases. In Ph-negative cases, 5-year OS was significantly higher in the high-volume centers at 52.7% (95% confidence interval [CI]: 49.9–55.5) versus 46.8% (95% CI: 43.8–49.7) for the low-volume centers (P < 0.01). Multivariate analysis identified high volume as a favorable prognostic factor (hazard ratio [HR]: 0.81 [95% CI: 0.72–0.92], P < 0.01). Subgroup analysis in Ph-negative cases revealed that the center effects were more evident in patients aged ≥40 years (HR: 0.72, 95% CI: 0.61–0.86, P < 0.01) and those receiving cord blood transplantation (HR: 0.62, 95% CI: 0.48–0.79, P < 0.01). In Ph-positive cases, no significant difference was observed between the high and low-volume centers for 5-year OS (59.5% [95% CI: 56.2–62.7] vs. 54.9% [95% CI: 51.3–58.3], P = 0.054). In multivariate analysis, center volume did not emerge as a significant prognostic indicator. This study showed center effects on survival in Ph-negative but not in Ph-positive cases, highlighting the heterogeneity of the center effect in allo-HSCT for B-cell acute lymphoblastic leukemia. Collaborative efforts among transplant centers and further validation are essential to improve outcomes.

DOI： 10.1016/j.jcyt.2024.05.004

Scopus

PubMed

Publisher：Proceedings of Science  

The cosmic MeV gamma-ray observation is a promising diagnostic tool to address the universe. While INTEGRAL and COMPTEL unveiled the MeV gamma-ray sky, the outstanding issue, like the origin of the gamma-ray and positron excesses toward the galactic inner region, remained. Furthermore, the conventional nonlinear imaging with the superposition of the Compton circles and the coded mask aperture system cannot discriminate the background from the signal. To overcome such difficulties, we developed an Electron-Tracking Compton Camera (ETCC), which has a linear imaging system. The balloon experiment on April 2018 in Australia, the so-called SMILE-2+, was carried out, and we observed the galactic diffuse gamma-rays with a significance of 4.3σ in the energy range of 150–600 keV. The gamma-ray flux was consistent with the point-source emission and the annihilation radiation from the positronium observed from INTEGRAL/SPI.

Scopus

Publisher：Journal of Luminescence  

Driven by the pursuit of optimizing the luminescent properties of garnet-based single crystals for X-ray imaging applications, this work reports on the successful synthesis and in-depth characterization of GYAGG crystals doped with Ce³⁺ or Tb³⁺ ions, and doubly-doped with both of them. Micro-pulling down synthesis yielded crystals with a single cubic phase confirmed by X-ray diffraction. Photoluminescence (PL) and radioluminescence (RL) measurements on Ce³⁺,Tb³⁺ co-doped GYAGG revealed bidirectional energy transfer processes. Characteristic broadband 5d<inf>1</inf>→4f emission of Ce³⁺ centers peaking at 530 nm and narrow 4f→4f emission lines of Tb³⁺ ions starting from ⁵D<inf>4</inf> level within 480–630 nm were observed. At higher doping levels, cross-relaxation in Tb³⁺ pairs resulted depleted ⁵D<inf>3</inf> state and only the emission from ⁵D<inf>4</inf> one was observed in the spectra. Analysis of PL decay characteristics corroborated the spectral observations, confirming progressively decreasing Ce³⁺ decay time (down to 40 ns at 15 % Tb³⁺) due to enhanced Ce³⁺→Tb³⁺ energy transfer. Similarly, the Tb³⁺ decay time accelerated by more than 60 % after the Ce³⁺ co-doping. Notably, co-doping with 0.5 % Ce³⁺ and 10–15 % Tb³⁺ doubled the luminescence intensity of RL spectra compared to 0.5 % Ce³⁺-doping alone, attributed to the increased density of emitting centers.

DOI： 10.1016/j.jlumin.2024.120663

Scopus

Language：English   Publisher：The Ceramic Society of Japan  

<p>This study focuses on the growth of transparent single crystals of Li₂CaSiO₄ (LCS) doped with Ce as neutron scintillator candidates. LCS is a light material with a high melting point and chemical stability; thus, LCS is applicable for use in high-flux neutron environments. However, the growth of transparent single crystals from the melt has been difficult owing to the phase transitions. In this study, the LiF/LiCl eutectic was used as a flux with a lower melting point and less decomposition than LiCl, and Ce was selected as the luminescent center. The phase diagram of the LiF/LiCl-LCS system was determined, and the conditions for crystal growth were optimized, consequently, transparent non-doped LCS and Ce:LCS crystals were successfully obtained. The alpha-ray-excited scintillation spectrum and scintillation decay time of Ce:LCS were measured in a feasibility study for neutron detection. The results showed that Ce:LCS has potential as a neutron scintillator, with a significantly fast decay time of 28.46 ns.</p>

DOI： 10.2109/jcersj2.23214

Open Access

Scopus

CiNii Research

Publisher：Optical Materials X  

High-quality Cs<inf>3</inf>Cu<inf>2</inf>I<inf>5</inf>:In single crystals with a 7 mm diameter were grown by using the vertical Bridgman method. These crystals have a high optical transmittance (>75 %) and emit a bright red-orange light under both UV and X-ray irradiation. The Cs<inf>3</inf>Cu<inf>2</inf>I<inf>5</inf>:In crystals can exhibit a high photoluminescence quantum efficiency (PLQY) of 79.5 %, thus we explored the potential applications for light-emitting diodes (LED). The fabricated LED demonstrated CIE color coordinates of (0.553, 0.431) with a color rendering index (Ra) of 77, making it suitable for supplementary light in plant growth. Moreover, we evaluated their gamma-ray spectroscopy capability by using an avalanche photodiode (APD) detector. Under ¹³⁷Cs gamma-ray irradiation, the gamma scintillation yield and energy resolution gradually degraded as the In concentration increased, which can be attributed to an enhanced afterglow after In doping.

DOI： 10.1016/j.omx.2024.100335

Open Access

Scopus

Publisher：Journal of Crystal Growth  

In this work, the effects of rare earth ion codoping on the optical and scintillation performance of Cs<inf>3</inf>Cu<inf>2</inf>I<inf>5</inf>:Tl single crystals were studied. Cs<inf>3</inf>Cu<inf>2</inf>I<inf>5</inf>:Tl single crystals codoped with different concentrations of Sc³⁺, Y³⁺, and La³⁺ ions were grown by the Bridgman method. It was found that rare earth ion codoping reduces the optical transmittance of the as-grown crystals, in particular the coloring caused by Sc³⁺codoping. The luminescence mechanism associated with self-trapped exciton (STE) and Tl-related emissions has not been affected by the introduction of rare earth ion. The gamma scintillation yield and energy resolution are degraded after rare earth ion codoping.

DOI： 10.1016/j.jcrysgro.2024.127717

Scopus

Publisher：Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment  

Although the MeV gamma-ray band is a promising energy-band window in astrophysics, the current situation of MeV gamma-ray astronomy significantly lags behind those of the other energy bands in angular resolution and sensitivity. An electron-tracking Compton camera (ETCC), a next-generation MeV detector, is expected to revolutionize the situation. An ETCC tracks each Compton-recoil electron with a gaseous electron tracker and determines the incoming direction of each gamma-ray photon; thus, it has a strong background rejection power and yields a better angular resolution than classical Compton cameras. Here, we study ETCC events in which the Compton-recoil electrons do not deposit all energies to the electron tracker but escape and hit the surrounding pixel scintillator array (PSA). The PSA provides additional information on the electron-recoil direction, which enables us to improve significantly the angular resolution. We developed an analysis method for this untapped class of events and applied it to laboratory and simulation data. We found that the energy spectrum obtained from the simulation agreed with that of the actual data within a factor of 1.2. We then evaluated the detector performance using the simulation data. The angular resolution for the new-class events was found to be twice as good as in the previous study at the energy range 1.0–2.0 MeV, where both analyses overlap. We also found that the total effective area is dominated by the contribution of the double-hit events above an energy of 1.5 MeV. Notably, applying this new method extends the sensitive energy range with the ETCC from 0.2–2.1 MeV in the previous studies to up to 3.5 MeV. Adjusting the PSA dynamic range should improve the sensitivity in even higher energy gamma-rays. The development of this new analysis method would pave the way for future observations by ETCC to fill the MeV-band sensitivity gap in astronomy.

DOI： 10.1016/j.nima.2024.169242

Scopus

Language：English   Publisher：Materials  

Aluminum garnets display exceptional adaptability in incorporating mismatching elements, thereby facilitating the synthesis of novel materials with tailored properties. This study explored Ce³⁺-doped Tb<inf>3</inf>Al<inf>5−x</inf>Sc<inf>x</inf>O<inf>12</inf> crystals (where x ranges from 0.5 to 3.0), revealing a novel approach to control luminescence and photoconversion through atomic size mismatch engineering. Raman spectroscopy confirmed the coexistence of garnet and perovskite phases, with Sc substitution significantly influencing the garnet lattice and induced A<inf>1g</inf> mode softening up to Sc concentration x = 2.0. The Sc atoms controlled sub-eutectic inclusion formation, creating efficient light scattering centers and unveiling a compositional threshold for octahedral site saturation. This modulation enabled the control of energy transfer dynamics between Ce³⁺ and Tb³⁺ ions, enhancing luminescence and mitigating quenching. The Sc admixing process regulated luminous efficacy (LE), color rendering index (CRI), and correlated color temperature (CCT), with adjustments in CRI from 68 to 84 and CCT from 3545 K to 12,958 K. The Ce³⁺-doped Tb<inf>3</inf>Al<inf>5−x</inf>Sc<inf>x</inf>O<inf>12</inf> crystal (where x = 2.0) achieved the highest LE of 114.6 lm/W and emitted light at a CCT of 4942 K, similar to daylight white. This approach enables the design and development of functional materials with tailored optical properties applicable to lighting technology, persistent phosphors, scintillators, and storage phosphors.

DOI： 10.3390/ma17112762

Open Access

Scopus

PubMed

Language：English   Publisher：Bone Marrow Transplantation  

Chronic myelomonocytic leukaemia (CMML) is a haematological malignancy with a poor prognosis. Allogeneic haematopoietic stem cell transplantation remains the only curative approach. Without human leucocyte antigen-matched related sibling donors, the optimal alternative donor has yet to be established. Although unrelated bone marrow transplantation (UBMT) has been extensively studied, cord blood transplantation (CBT) for CMML remains largely unexplored. This nationwide retrospective study compared the outcomes of UBMT and single-unit umbilical CBT in patients with CMML. This study included 118 patients who underwent their first allo-HSCT during 2013–2021. Of these, 50 received BMT (UBMT group), while 68 underwent CBT (CBT group). The primary endpoint was the 3-year overall survival (OS). There were comparable 3-year OS rates between the UBMT (51.0%, 95% confidence interval [CI]: 34.1–65.5%) and CBT (46.2%, 95% CI: 33.2–58.1%; P = 0.60) groups. In the inverse probability of treatment weighting analysis, CBT did not show significantly improved outcomes compared with UBMT regarding the 3-year OS rate (hazard ratio 0.97 [95% CI: 0.57–1.66], P = 0.91). Thus, CBT may serve as an alternative to UBMT for patients with CMML. Further research is necessary to optimise transplantation strategies and enhance outcomes in patients with CMML undergoing CBT.

DOI： 10.1038/s41409-024-02223-4

Scopus

PubMed

Publisher：Journal of Alloys and Compounds  

This study provided the first in-depth investigation of the effects of large dopant incompatibility (Pr³⁺ and La³⁺ ions) on the small host lattice element (Lu³⁺) in Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (LuAG) single crystal. The growth of such complex crystals from the melt presented many challenges. By engineering the ionic radius ratio of RE- and M-site cations, a single-crystal phase stabilized by configurational entropy was achieved. This investigation elucidated the crystallization behavior of configurationally disordered rare-earth aluminum garnet oxide (Lu<inf>1−x−y</inf>Pr<inf>x</inf>La<inf>y</inf>)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> from the melt and characterized its functional properties, including microstructural, optical, photoluminescence, and scintillation properties, between 5 and 300 K. Relaxation of the imposed strain energy led to local perturbations and destabilization of the garnet structure. Multielemental EDS mapping, micro-Raman spectroscopy, and thermoluminescence revealed the mechanism by which atomic size mismatch drove a smooth transition from the garnet to the perovskite phase in high entropy garnets. The optical, photoluminescence, and scintillation measurements provided fundamental insights into property changes driven by incompatibility doping. Standard and modified Judd-Ofelt theory analysis of absorption spectra determined the phenomenological Judd-Ofelt parameters Ω<inf>λ</inf> and radiative lifetimes. Atomic size mismatch engineering offers a promising approach to overcoming the limitations of conventional eutectic synthesis methods.

DOI： 10.1016/j.jallcom.2024.174078

Scopus

Publisher：Optical Materials X  

The influence of nonstoichiometric engineering on the scintillation properties of Ce³⁺ doped yttrium aluminum perovskite (YAP:Ce) crystals was investigated. Crystals with slight yttrium excess (Y<inf>1</inf> <inf>·</inf> <inf>004</inf>AlO<inf>3</inf>:Ce), yttrium deficiency (Y<inf>0</inf> <inf>·</inf> <inf>994</inf>AlO<inf>3</inf>:Ce), and stoichiometric composition (YAlO<inf>3</inf>:Ce) were synthesized using the micro-pulling down method. Structural characterization confirmed crystallization in the pure orthorhombic Pnma space group for all compositions. Optical absorption spectroscopy revealed an extensive background in the nonstoichiometric crystals due to the increased degree of light scattering centers associated with the defects. The photoluminescence excitation and emission spectra of Ce³⁺ ions were unaffected by nonstoichiometry. However, the scintillation decay kinetics and light yield exhibited marked improvements in the Y<inf>1±x</inf>AlO<inf>3</inf>:Ce (x≠0) crystals. The light yield increased by 22 % and 15 % and the slower component of the decay accelerated from 171 ns to 106 and 131 ns compared to the stoichiometric crystal. Thermoluminescence glow curves revealed that nonstoichiometry significantly altered the concentrations of antisite defects and oxygen vacancies. The EPR spectroscopy investigations revealed a correlation between the Ce³⁺ ions concentration and the degree of nonstoichiometry. Strategic engineering of nonstoichiometry in Y<inf>1±x</inf>AlO<inf>3</inf>:Ce (x≠0) scintillators may have provided an effective approach to optimizing scintillation performance.

DOI： 10.1016/j.omx.2024.100295

Open Access

Scopus

Language：English   Publisher：Transplantation and Cellular Therapy  

The present study compared lower-dose melphalan (80 mg/m², FM80) and higher-dose melphalan (140 mg/m², FM140) when administering reduced-intensity conditioning with fludarabine in adult patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed nationwide registry data (2006 to 2019) and compared transplant outcomes between the 2 groups. Ninety-two patients (median age, 61 [interquartile range, 56 to 65] years) were assigned to the FM80 and FM140 groups by propensity score matching. The 3-year overall survival (OS) rate in the FM140 group (63.9%; 95% confidence interval [CI], 52.9% to 73.0%) was significantly higher than that in the FM80 group (54.2%; 95% CI, 37.1% to 52.1%) (P = .038). The FM140 group had a nonsignificantly (P = .095) lower 3-year cumulative incidence of relapse (15.5%; 95% CI, 8.9% to 23.8% versus 26.0%; 95% CI, 17.3% to 35.5%). The 3-year cumulative incidences of nonrelapse mortality were 22.3% (95% CI, 14.1% to 31.8%) and 23.7% (95% CI, 15.4% to 33.2%) in the FM80 and FM140 groups, respectively (P = .49). The beneficial effect of FM140 was more evident in patients with a poor cytogenetic risk. Our findings suggest the superiority of FM140 in patients with MDS undergoing allo-HSCT, especially in high-risk patients.

DOI： 10.1016/j.jtct.2024.01.083

Scopus

PubMed

Publisher：Physical Review Materials  

Recent intensive studies in metallic kagome systems have revealed various correlated topological and electronic states, leading to their spintronic applications. The kagome ferromagnetic metal Fe3Sn has been found to host a topological nodal plane near the Fermi energy and exhibits large transverse transport responses. Here we report the fabrication of the epitaxial thin films of Fe3Sn and the observation of its large anomalous Nernst effect (ANE). Structural and magnetic measurements reveal (0001)-orientated epitaxial growth of kagome D019 Fe3Sn and the magnetic easy plane along the substrate plane. Moreover, transport measurements confirm the large ANE of 2.4 μV/K at room temperature, comparable to that of the bulk polycrystalline samples. The obtained Fe3Sn film should be useful for thermoelectric applications, because the binary compound based on inexpensive elements exhibits large spontaneous ANE voltage under an out-of-plane heat current due to the magnetic and electronic states stabilized by the magnetic anisotropy.

DOI： 10.1103/PhysRevMaterials.8.054206

Scopus

Publisher：Optical Materials X  

Pr-doped scintillators are attracting attention because of their potential applications in medical devices. In this study, we focused on Pr-doped (La, Y)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillators to grow single crystals by the micro-pulling-down method and to evaluate their optical and scintillation properties. From the powder XRD results, the crystal structure and the space group were identified to be monoclinic and P2<inf>1</inf>/n, respectively. The results of optical and scintillation characterization show that the luminescence from the Pr³⁺ 5d<inf>1</inf>–4f transition increases with increasing Pr³⁺ concentration. The maximum light yield was also obtained for the sample with the highest Pr³⁺ concentration. The Pr-doped (La, Y)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> single crystal shows promising properties for application in radiation detection.

DOI： 10.1016/j.omx.2024.100318

Open Access

Scopus

Language：Japanese   Publisher：公益社団法人 応用物理学会  

DOI： 10.11470/houshasen.49.1_1

CiNii Research

Publisher：Proceedings of Science  

An experiment has been planned to measure the half-life of double beta decay with two-neutrino emission for ⁹⁶Zr nuclei. A newly designed 2ν-ZICOS detector will observe about 100 events of ⁹⁶Zr double beta decay. The detector will use an ultra-pure quartz flask and 20 Hamamatsu H3378-50 photomultipliers in order to distinguish the signal shape of Cherenkov lights. The liquid scintillator containing 0.4 g of ⁹⁶Zr will be filled in the ETFE cubic bag. The transparency of 50 µm thickness ETFE sheet for scintillation light was 97.5% at minimum. The constructions of a radiation shield using Pb blocks and the setup of 2ν-ZICOS detector will start in May 2024 at LAB-A in Kamioka mine, and the observation will start in next summer or autumn at the latest.

Scopus

Publisher：Proceedings of Science  

The Weakly Interacting Massive Particles (WIMPs) are considered to be the hypothetical particles that have been the leading candidate for dark matter for decades. The PICOLON project is directly searching for WIMPs dark matter using ultra-pure NaI(Tl) crystals at the Kamioka underground laboratory. To determine the WIMP sensitivity, it is necessary to know the quenching factor (QF) of NaI(Tl), which is the scintillation light yield ratio of nuclear recoil and electron recoil at the same energy deposit. Several groups reported the QF absolute values and its energy dependence in the low energy region (less than 100 keV), however the results are not in good agreement. It is still unsolved whether the disagreement is due to the individual crystal differences or the effect of systematic errors. In this paper, we report the QF of ultra-pure NaI(Tl) crystal developed by PICOLON group. To measure the QF, the crystal was irradiated with 2.45-MeV monochromatic neutrons generated by a discharge-type compact D-D fusion neutron source at the Institute of Advanced Energy, Kyoto University. The QFs of Na were obtained at six points in the range of 19-101 keV<inf>nr</inf>

Scopus

Publisher：Journal of Crystal Growth  

For the decommissioning of Fukushima Daiichi Nuclear Plants, a novel real-time dose-rate monitor consisting of a scintillator, 100-m long optical fiber and CCD spectrometer has been proposed, and this scintillation material is required to have an emission wavelength of longer than approximately 650 nm. In this paper, as a candidate material for the system, we focused on Ce/Cr co-doped Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf> (Ce/Cr:GGG) single crystals grown by the micro-pulling down method. Since the light output of this material was expected to depend on the Cr³⁺ concentration, we investigated the relationship between Cr segregation and luminescence properties in Ce/Cr:GGG crystal. Generally, a single photon counting method is not available to evaluate its light output accurately due to the long decay time, we used a novel technique “emission-intensity two-dimensional- mapping method” (2D-image method) to verify the light intensity at each point of the sample. This method realized estimation of the light intensity within the sample, though segregation of Cr³⁺ is observed. The results showed that Cr was concentrated in the center part along the radial direction in the grown crystals, while all parts had an emission wavelength of approximately 730 nm excited by X-ray. Using the 2D-image method, emission intensity was found to correspond to the Cr concentration, and its correlation coefficients between emission intensity and Cr concentration were over 0.8. We found that our material is available for the monitoring system when the Cr dense part of the crystal is cut and used.

DOI： 10.1016/j.jcrysgro.2024.127581

Scopus

Language：Japanese   Publisher：Japan Radioisotope Association  

<p>Early diagnosis based on pathophysiology enables optimal treatment. Nuclear medicine is one of the methods for visualizing organ functions and leading to early diagnosis. single photon emission computed tomography (SPECT) is widely used and supports clinical practice. However, the performance of SPECT is not sufficient to meet recent diagnostic needs. In this paper, we argue that the prospects and challenges of replacing part of SPECT with positron emission tomography.</p>

DOI： 10.3769/radioisotopes.73.109

CiNii Research

Publisher：Japanese Journal of Applied Physics  

A calculation model for predicting the temperature characteristics of the double-layered resonator (DRL) was developed by using the total strain ratio including the influence of the waves reflected at the bonding boundary. The validity of the model proposed was examined from the comparison between the measured and calculated results for a DRL specimen consisting of 129.55°Y- and 0°Y-quartz substrates. The calculation results of the model proposed demonstrated that it is possible to predict the trends of changes in experimental values of temperature characteristics not only in the 1st-order mode but also in the higher-order modes. In addition, the changes in the particle displacement distribution and temperature characteristics of the DLR obtained by the model proposed were also in good agreement with the results of finite element method analysis. The proposed model is expected to greatly contribute to the design of DLRs with high excitation efficiency and excellent temperature characteristics.

DOI： 10.35848/1347-4065/ad1fb1

Scopus

Publisher：Journal of Crystal Growth  

³He gas detectors have been commonly used in applied technology related to thermal neutron detectors; however, owing to the depletion of ³He, applications using solid-state scintillators are expanding. In recent years, our group has reported a novel Tl:CsI/⁶LiBr eutectic scintillator for thermal neutron detection, which has excellent light yield and (n,γ) discrimination ability. In practical applications of eutectic scintillators, achieving eutectic production precisely at the eutectic point is crucial to ensure a high production yield and the development of a uniform eutectic structure. However, the phase diagram of the CsI-LiBr system has not yet been reported. In this study, the phase diagram obtained from calorimetry was investigated. Furthermore, eutectic fabrication was performed at the eutectic point, and the neutron response was evaluated.

DOI： 10.1016/j.jcrysgro.2023.127543

Scopus

Publisher：Journal of Instrumentation  

Real-time dose-rate monitoring system under the high dose-rate situation is required for the decommissioning of Fukushima Daiichi Nuclear Plants to remove the debris remaining inside the plants. We have proposed a dose-rate monitor consisting of a scintillator, over 100-m long optical fiber and CCD spectrometer. Some noises with a dominant emission wavelength of below 550 nm originating from the optical fiber itself must be separated from the signal from the scintillator, and the signal region has been defined as 650–1000 nm to use significant data, up to now. In this paper, we investigated if the noise region defined as below 550 nm can be supporting data for the monitoring system, because such noises are expected to include position information through the fiber. In the emission spectrum, the intensities of the noise emission or absorption band are expected to depend on the position of the fiber, and we demonstrated such dependence, “one-dimensional dose-rate distribution”, with 20 m-long optical fiber and CCD spectrometer. Optical fiber was placed around a ⁶⁰Co source with an activity of approximately 60 TBq, and emission spectra of the fiber were acquired with different dose-rate conditions from 10 to 700 Gy/h. The noise intensities were well fitted with the power function as a function of the product of fiber length and dose rate, and we found that fiber noise has rate information in one-dimensional imaging.

DOI： 10.1088/1748-0221/19/02/C02053

Scopus

Publisher：Journal of Crystal Growth  

Mg<inf>2</inf>Si/Si eutectics are grown from melt by the Vertical Bridgman method using a carbon crucible at three pulling rates. All the Mg<inf>2</inf>Si/Si eutectics are composed of Mg<inf>2</inf>Si and Si phases, and the eutectic structure becomes finer with an increase in the pulling rate. Increasing the pulling rate systematically decreases the thermal conductivities of the Mg<inf>2</inf>Si/Si eutectics, suggesting that a decrease in the thermal conductivity is attributed to an increase in phonon scattering at the boundaries between the two phases. The power factor and figure of merit of the Mg<inf>2</inf>Si/Si eutectics are larger than those of Mg<inf>2</inf>Si above 400 °C because of the increase in the Seebeck coefficient. The figure of merit, ZT, of the Mg<inf>2</inf>Si/Si eutectics solidified at a 10³ mm/min pulling rate reached 0.076 at 600 °C.

DOI： 10.1016/j.jcrysgro.2023.127533

Scopus

Publisher：Crystals  

The ³He gas is commonly used for the detection of thermal neutrons. However, with the depletion of ³He gas, there is a need to develop new solid scintillators for thermal neutron detection. Solid scintillators containing ⁶Li, which have large neutron capture cross-sections and a large amount of energy released by transmutation reactions, are commonly used as alternative candidates. However, only single-crystal scintillators are currently used, and their ⁶Li concentration is limited by their chemical composition. In this study, we designed, grew, and evaluated a new eutectic scintillator, Rb<inf>2</inf>CeCl<inf>5</inf>/LiCl, which can improve the ⁶Li concentration compared with single-crystal scintillators. Rb<inf>2</inf>CeCl<inf>5</inf>, which was selected as the scintillator phase, has excellent scintillator properties (light yield: 36,000 photons/MeV, decay time: mostly 24 ns, slightly 153 ns), and is less deliquescent than other halide scintillators. The crystal grown using the vertical Bridgman method exhibited a eutectic phase composed of Rb<inf>2</inf>CeCl<inf>5</inf> and LiCl. The eutectic crystals exhibited Ce³⁺ 5d-4f emissions, with a peak between 360 and 370 nm. The Rb<inf>2</inf>CeCl<inf>5</inf> phase was identified as the luminescent phase via cathodoluminescence mapping, and 16,000 photons/neutron of the light yield and 56.1 ns of the decay time were observed. This study indicates that the Rb<inf>2</inf>CeCl<inf>5</inf>/LiCl eutectic scintillator is a promising candidate for use in thermal neutron detectors.

DOI： 10.3390/cryst14020154

Open Access

Scopus

Publisher：Laser and Photonics Reviews  

The urgency for cost-effective, high-resolution, flexible X-ray imaging detectors is generating great demand for scintillators with low-temperature processability, high scintillation yield, and negligible afterglow. X-ray imaging materials are currently dominated by inorganic scintillators in the form of rigid films and bulk crystals, which have inherent limitations including high-temperature, complex synthesis, and considerable challenges toward advanced nonplanar imaging. Here, high-performance and flexible X-ray scintillators based on novel zero-dimensional (0D) (BTPP)<inf>2</inf>MnX<inf>4</inf> (BTPP = benzyltriphenylphosphonium; X = Cl, Br) halides are reported. They emit bright green light originating from the ⁴T<inf>1</inf>-⁶A<inf>1</inf> transition of Mn²⁺ under X-ray excitation. In particular, (BTPP)<inf>2</inf>MnBr<inf>4</inf> single crystals exhibit excellent air- and radiation-stability, a high scintillation yield of 53 000 photons MeV⁻¹, a low detection limit of 89.9 nGy<inf>air</inf> s⁻¹, and an ultralow afterglow comparable to commercial Bi<inf>4</inf>Ge<inf>3</inf>O<inf>12</inf> (BGO) single crystals. Moreover, the (BTPP)<inf>2</inf>MnCl<inf>4</inf>@polydimethylsiloxane (PDMS) flexible scintillation screens achieve a high spatial resolution of 14.1 lp mm⁻¹ and realize high-quality imaging results of nonplanar objects. This study demonstrates that the flexible scintillation screens based on low-dimensional Mn(II) hybrid halides have significant potential for low-dose and high-resolution X-ray imaging applications.

DOI： 10.1002/lpor.202300860

Scopus

Language：English   Publisher：British Journal of Haematology  

Allogeneic haematopoietic stem cell transplantation (HCT) is the curative treatment for myelodysplastic syndrome with a complex karyotype (CK-MDS). However, only a few studies have been limited to patients with CK-MDS undergoing allogeneic HCT. This study aimed to identify the risk factors for patients with CK-MDS undergoing allogeneic HCT. We included 691 patients with CK-MDS who received their first allogeneic HCT. The overall survival (OS) was the primary end-point, estimated using the Kaplan–Meier method. Prognostic factors were identified using a Cox proportional hazards model. The 3-year OS was 29.8% (95% confidence interval [CI]: 26.3–33.3). In the multivariable analysis, older age (hazard ratio [HR]: 1.44, 95% CI: 1.11–1.88), male sex (HR: 1.38, 95% CI: 1.11–1.71), poor haematopoietic cell transplant comorbidity index (HR: 1.47, 95% CI: 1.20–1.81), red blood cell transfusion requirement (HR: 1.58, 95% CI: 1.13–2.20), platelet transfusion requirement (HR: 1.85, 95% CI: 1.46–2.35), not-complete remission (HR: 1.55, 95% CI: 1.16–2.06), a high number of karyotype abnormality (HR: 1.63, 95% CI: 1.18–2.25) and monosomal karyotype (HR: 1.49, 95% CI: 1.05–2.12) were significantly associated with OS. Thus, the 3-year OS of allogeneic HCT was 29.8% in patients with CK-MDS, and we identified risk factors associated with poor OS.

DOI： 10.1111/bjh.19139

Scopus

PubMed

Language：English   Publisher：Nature Materials  

Multiferroic materials, particularly those possessing simultaneous electric and magnetic orders, offer a platform for design technologies and to study modern physics. Despite the substantial progress and evolution of multiferroics, one priority in the field remains to be the discovery of unexplored materials, especially those offering different mechanisms for controlling electric and magnetic orders¹. Here we demonstrate the simultaneous thermal control of electric and magnetic polarizations in quasi-two-dimensional halides (K,Rb)<inf>3</inf>Mn<inf>2</inf>Cl<inf>7</inf>, arising from a polar–antipolar transition, as evidenced using both X-ray and neutron powder diffraction data. Our density functional theory calculations indicate a possible polarization-switching path including a strong coupling between the electric and magnetic orders in our halide materials, suggesting a magnetoelectric coupling and a situation not realized in oxide analogues. We expect our findings to stimulate the exploration of non-oxide multiferroics and magnetoelectrics to open access to alternative mechanisms, beyond conventional electric and magnetic control, for coupling ferroic orders.

DOI： 10.1038/s41563-023-01759-y

Scopus

PubMed

Publisher：Journal of Alloys and Compounds  

Halide compounds with chemical formula A<inf>2</inf>MX<inf>6</inf> (A: alkali metal or Tl, M: tetravalent metal, X: halogen) have previously been reported as intrinsic scintillators. However, some application fields e.g., utilizing waveguides, require novel scintillators with emission wavelengths longer than that of Cs<inf>2</inf>HfI<inf>6</inf> as bright and red/infrared scintillators. Thus, in this study, cation-substituted Cs<inf>2</inf>HfI<inf>6</inf> crystals (Rb<inf>2</inf>HfI<inf>6</inf>, K<inf>2</inf>HfI<inf>6</inf>, Cs<inf>2</inf>ZrI<inf>6</inf>, Rb<inf>2</inf>ZrI<inf>6</inf>, and K<inf>2</inf>ZrI<inf>6</inf>) were grown using the vertical Bridgman method, and their crystal structures were analyzed via single-crystal X-ray diffraction. The crystal structures of Cs<inf>2</inf>HfI<inf>6</inf> and Cs<inf>2</inf>ZrI<inf>6</inf> were determined to be cubic (space group: Fm3̅m), Rb<inf>2</inf>HfI<inf>6</inf> and Rb<inf>2</inf>ZrI<inf>6</inf> were tetragonal (space group: P4/mnc), and K<inf>2</inf>HfI<inf>6</inf> and K<inf>2</inf>ZrI<inf>6</inf> were monoclinic (space group P2<inf>1</inf>/c). In addition, the emission spectra of Rb<inf>2</inf>HfI<inf>6</inf>, K<inf>2</inf>HfI<inf>6</inf>, Rb<inf>2</inf>ZrI<inf>6</inf>, and K<inf>2</inf>ZrI<inf>6</inf> showed that their peaks exhibited a 25 nm red-shift in comparison with that of Cs<inf>2</inf>HfI<inf>6</inf>, whereas those of Cs<inf>2</inf>ZrI<inf>6</inf> did not. For A<inf>2</inf>MI<inf>6</inf> compounds, the emission was effectively determined by A-site cation substitution. Moreover, the pulse-height spectra were successfully measured for A<inf>2</inf>HfI<inf>6</inf>. The scintillation light outputs of Cs<inf>2</inf>HfI<inf>6</inf>, Rb<inf>2</inf>HfI<inf>6</inf>, and K<inf>2</inf>HfI<inf>6</inf> were estimated to be approximately 60,000, 40,000, and 33,000 photons/MeV, respectively.

DOI： 10.1016/j.jallcom.2023.172506

Scopus

Publisher：Proceedings of SPIE the International Society for Optical Engineering  

MeV gamma-ray observations provide unique information about nucleosynthesis, diffusion in our galaxy, low-energy cosmic rays, particle acceleration, and other phenomena. However, the detection sensitivity in this band is significantly lower than that in other bands due to a large background contamination. To address this issue, we are developing an electron-tracking Compton camera (ETCC) with powerful background rejection tools based on Compton recoil electron tracks. This will enable future observations to be conducted with greater sensitivity. We have successfully demonstrated the detection technology and performance of the ETCC with two balloon experiments. We are preparing for the next balloon flight, SMILE-3, to observe galactic diffusion gamma rays and some bright celestial objects.

DOI： 10.1117/12.3016872

Scopus

Publisher：Proceedings of SPIE the International Society for Optical Engineering  

HiZ-GUNDAM is a future satellite mission whose mission concept was approved by ISAS/JAXA, and it is one of the future satellite candidates of JAXA's competitive medium-class mission. HiZ-GUNDAM will lead time-domain astronomy in 2030s, and its key sciences are (1) exploration of the early universe with high-redshift gamma-ray bursts, and (2) contribution to the multi-messenger astronomy. Two mission payloads are aboard HiZ-GUNDAM to realize these two scientific issues. The wide field X-ray monitors which consist of Lobster Eye optics array and focal imaging sensor, monitor ~0.5 steradian field of view in 0.5-4 keV energy range. The near infrared telescope with an aperture size of 30 cm in diameter performs simultaneous 5-band photometric observation in 0.5-2.5 µm wavelength with Koester's prism for X-ray transients discovered by Wide Field X-ray Monitor. In this paper, we introduce the mission overview of HiZ-GUNDAM while the information contained herein may change in future studies.

DOI： 10.1117/12.3018571

Scopus

Publisher：Journal of Physics Conference Series  

The luminescence characteristics of Gd3Al2Ga3O12:Ce3+ garnet scintillator crystals codoped with Li+ and Mg2+ ions were investigated. The excitation and emission spectra were obtained within the energy range of 3.6-21.6 eV, at both liquid helium and room temperature conditions to examine the effects of Li+ and Mg2+ codoping on cerium valence states, gadolinium-cerium energy transfer, and defect formation. Codoping with Mg2+ was found to efficiently convert Ce3+ to Ce4+, evidenced by significant changes in the shapes of the excitation spectra profile for Ce3+ luminescence in the exciton range, while Li+ had little impact. The presence of the high concentration of Ce4+ ions hampered the Gd3+→Ce4+ energy transfer. Redshifts in Ce3+ emission peaks indicated codopant-induced perturbations to the crystal field environment. The significant changes in the location of the Ce3+ excitation bands of Ce3+ luminescence in the exciton range further suggested alterations in the elemental distributions by the creation of complex defect clusters, particularly with Mg2+ codoping. The results demonstrate that Li+ and Mg2+ uniquely impact cerium valence, energy transfer processes, and structural properties in GAGG:Ce crystals.

DOI： 10.1088/1742-6596/2712/1/012011

Open Access

Scopus

Publisher：ISIJ International  

The thermophysical properties of molten Fe–Cu alloys, including density, surface tension, and viscosity, were measured using the electrostatic levitation furnace aboard the International Space Station (ISS-ELF) under microgravity conditions, which provided an environment that facilitated accurate measurements. The densities of the molten Fe–25at%Cu and Fe–50at%Cu alloys decreased linearly with increasing temperature, and higher copper compositions resulted in increased density. The surface tension of the molten alloys exhibited a unique up-convex temperature dependence curve that initially increased and then decreased as the temperature increased. Viscosity measurements indicated that the viscosity of the molten Fe–Cu alloys decreased with increasing temperature, following a quadratic curve, and that an increase in the copper composition resulted in lower viscosity.

DOI： 10.2355/isijinternational.ISIJINT-2024-277

Open Access

Scopus

Language：Japanese   Publisher：The Japan Society of Applied Physics  

Real-time dose-rate monitoring system under the high dose-rate situation is required for the decommissioning of the Fukushima Daiichi Nuclear Plants to remove the debris remaining inside the plants. We have proposed a dose-rate monitor consisting of a scintillator, over 100-m long optical fiber and CCD spectrometer. Some noises with a dominant-emission wavelength band of below 550 nm originating from the optical fiber itself must be separated from the scintillator emission light in 650-1000 nm, which is used as signal data, up to now. In this paper, we investigated if the noise region defined as below 550 nm is available for the position estimation of the hot spot through the fiber. The intensities of the noise emission or absorption band of such fiber-emission spectra are expected to depend on the hot-spot position through the fiber, and we demonstrated such dependence, “one-dimensional dose-rate distribution”, with a 20 m-long optical fiber and CCD spectrometer. Two types of optical fibers (High OH and Low OH) were tested under several length conditions of the fiber from the CCD spectrometer to 60Co source. The results of the emission spectra showed the intensity ratio of absorption to maximum intensity peak decreased as such length condition increased. We found that fiber noise is available for the position estimation for the hotspots (debris).

DOI： 10.11470/houshasen.49.1_18

CiNii Research

Publisher：Ceramics International  

Scintillators are used not only as single crystals in radiation detection systems but also as arrays, columns, and fibers. In this study, a novel optical-guiding crystal scintillator (OCS) was fabricated using an Eu:SrI<inf>2</inf> crystal as the core and borosilicate glass as the cladding. The OCS has an elongated shape and can be flexibly processed like an optical fiber. Furthermore, because inorganic scintillator crystals are used as the core, the OCS has high sensitivity to high-energy radiation, such as γ- and X-ray radiation, unlike plastic scintillators. In this study, by observing the cross section of the fabricated OCS, identifying the crystal structure, and investigating the radioluminescence spectrum under X-ray irradiation, OCS fabrication in accordance with the OCS design specifications was confirmed, and the SrI<inf>2</inf> crystal structure and Eu²⁺ 5d–4f luminescence were maintained. The γ-ray responses, such as light yield and decay time, were also investigated.

DOI： 10.1016/j.ceramint.2022.12.264

Scopus

Publisher：Journal of Instrumentation  

Internal exposure for decommissioning workers at the Fukushima Daiichi Nuclear Power Plant must be prevented, and we have developed a monitoring system for alpha-ray emitting dust (alpha dust). When the dust size is less than several tens of micrometers, a dust protection mask does not work effectively to prevent internal exposure. Since no devices have been operated to observe alpha-dust images in real-time up to now, we have developed an alpha-ray imaging detector consisting of a scintillation material and imaging detector. Scintillators are required to have high light output and chemical stability. Cs<inf>3</inf>Cu<inf>2</inf>I<inf>5</inf> (CCI) scintillator was found to be one of the candidates, and an imaging test was operated with this material. The CCI crystal was grown by the Bridgman-Stockberger method, and a scintillation sheet for alpha-ray imaging was prepared by CCI microcrystals with a thickness of approximately 70 μm on a 200-μm thickness transparent polyethylene terephthalate film as a first imaging test. The sheet was irradiated with 5.5-MeV alpha rays from an ²⁴¹Am source, and scintillation photons were detected with a CMOS camera through an optical lens. We succeeded in visualizing alpha rays, and a position resolution of our system achieved approximately 16.2 ± 2.6 μm (10-90 %). This resolution was similar value to other imaging devices with Ag:ZnS powder scintillator, and a CCI single crystal sheet was expected to reach better resolution.

DOI： 10.1088/1748-0221/18/12/C12009

Scopus

Publisher：Journal of the American Ceramic Society  

In this study, a new Cs<inf>4</inf>SrI<inf>6</inf>:Yb²⁺,Sm²⁺ near-infrared (NIR) emitting scintillator was developed using sensitization strategy. It was found that Yb²⁺ sensitization significantly enhances the NIR radioluminescence (RL) of Sm²⁺, providing a new approach of designing highly emissive sensitized NIR scintillators. By studying the optical spectra and decay kinetics of Cs<inf>4</inf>SrI<inf>6</inf>:Yb²⁺,Sm²⁺, it was revealed that the energy transfer pathways involve both radiative and nonradiative processes. The gamma spectroscopy performance of Cs<inf>4</inf>SrI<inf>6</inf>:Yb²⁺,Sm²⁺ single crystals was studied by using the high-quantum-efficiency avalanche photodiode (APD) as the readout. Our results highlight the importance of using sensitization strategy of achieving NIR emitting scintillators and demonstrate the significant potential for radiation detection applications.

DOI： 10.1111/jace.19302

Scopus

Publisher：Applied Physics Express  

Li<inf>2</inf>HfBr<inf>6</inf> with host emission was grown as a gamma-ray- and neutron-sensitive scintillator. Decay time of Li<inf>2</inf>HfBr<inf>6</inf> was estimated to be less than 5 μs, and single-photon counting is available to evaluate its light output. The emission wavelength under X-ray excitation was approximately 570 nm, which is a longer wavelength than that of commonly used neutron scintillators, e.g. Li-glass. The light output excited by thermal neutrons was estimated to be 52000 photons per thermal neutron, which is approximately eight to nine times higher than that of Li-glass. Additionally, neutrons and gamma rays were discriminated using the pulse-shaped discrimination technique for Li<inf>2</inf>HfBr<inf>6</inf>

DOI： 10.35848/1882-0786/ad03ab

Open Access

Scopus

Publisher：Aip Conference Proceedings  

We report on inorganic crystal purification for the search for the neutrinoless double-beta decay of 48Ca using CaF2 crystals. We are working on the purification of CaF2 crystal, which is made from water-insoluble raw materials. The goal of the purity in this crystal is ≤1 μBq/kg. We measured the impurities in the crucible and CaF2 powder before we made a molten product of the CaF2. We will consider the correlation between the purity contained in the materials around the crystal growth and the purity of the molten product. The material-selection policy and prospects for the large-volume detector system will be discussed.

DOI： 10.1063/5.0161258

Scopus

Publisher：Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms  

We have launched a new research project named “ONOKORO” to elucidate the formation mechanism of clusters in atomic nuclei. The project comprehensively investigates clustering phenomena in the medium-to-heavy mass region with inverse-kinematics cluster-knockout reactions at the intermediate energy facilities. The new detector array named “TOGAXSI” is under construction for this purpose. It measures scattering angles and the energies of deuterons, tritons, ³He, and α particles emitted at forward angles from the cluster-knockout reactions. It also measures the recoil protons emitted from the scattering events at large angles. High-angular and high-energy resolutions with wide solid angles are required to achieve a good cluster separation energy resolution and a reasonably high yield. The designed telescope consists of silicon trackers and GAGG:Ce calorimeters. This paper shows the required conditions and design concepts of TOGAXSI.

DOI： 10.1016/j.nimb.2023.05.054

Scopus

Publisher：Optical Materials  

(La<inf>0.99</inf>Yb<inf>0.01</inf>)<inf>2</inf>Hf<inf>2</inf>O<inf>7</inf> (Yb:LaHO) crystal has been developed by the core heating method as a near-infrared-emitting oxide scintillator for a fiber reading remote-dosimetry system under the high-dose-rate region. This system consists of a scintillator, a long silica optical fiber and a detector unit. Near-infrared-emitting photons can be separated from significant fiber-derived noise mainly observed in the UV–blue range. The noise is generated in the optical fiber itself by gamma-rays and charged particles. The Yb:LaHO crystal had a maximum emission peak at 975 nm when excited by X-rays and a transmittance of approximately 29% at 977 nm. The afterglow intensity of the Yb:LaHO crystal under X-rays was 11% that of Cr:α-Al<inf>2</inf>O<inf>3</inf> (ruby) crystal. We demonstrated the applicability of the remote-dosimetry system with the Yb:LaHO crystal irradiated with gamma rays from a ⁶⁰Co source with an activity of ∼77 TBq. The signal-to-noise ratio (SNR) of the Yb:LaHO crystal was 1.9 times higher than that of the ruby crystal at ∼ 1 kGy/h, and the lowest limit of the dynamic range was comparable between the Yb:LaHO and ruby crystals. The results of the SNR and afterglow intensity showed that the Yb:LaHO crystal is a more suitable scintillator than the ruby crystal for fiber reading remote-dosimetry systems.

DOI： 10.1016/j.optmat.2023.113941

Scopus

Publisher：IEEE Transactions on Nuclear Science  

In this study, Ce:6LiCl/LaCl3 with a high 6Li concentration was developed as a novel thermal neutron scintillator, in which Ce3+ serves as an activator for the LaCl3 phase. The Ce:6LiCl/LaCl3 eutectic was grown in a quartz ampoule (inner diameter: 4.0 mm) using the Bridgman-Stockbarger technique. The grown eutectic contained 0.038 mol/cm36Li, which is greater than that found in commercially available scintillators such as LiCaAlF6 single crystals and Li glass. The Ce:6LiCl/LaCl3 eutectic has a lamellar eutectic structure and is optically transparent. A 350-nm emission due to Ce3+ 4f-5d transition was observed. The light yield under neutron irradiation was estimated to be 5.0 times higher than that of Li glass. In this eutectic, the 6Li ( n , a 3 H reaction made the 6LiCl phase to act as the neutron capture phase and LaCl3 to act as the scintillator phase.

DOI： 10.1109/TNS.2023.3271639

Scopus

Publisher：IEEE Transactions on Nuclear Science  

In this study, a novel thermal neutron scintillator of Tl:CsI/LiBr was developed. The eutectics were fabricated at various growth rates and investigated their scintillation properties. As a material design guideline, Tl:CsI, which has an excellent ratio, was selected as the scintillator phase to realize high light yield at the energy of rays and tritons generated by the nuclear transmutation reaction with 6Li and LiBr, which has a refractive index close to that of CsI, was selected as the neutron capture phase. Radioluminescence (RL) measurement under X-ray irradiation was also performed to obtain the emission spectrum of the eutectics. The light yield and decay time for thermal neutron were measured using 252Cf and were much higher than those of conventional scintillators for thermal neutron. Furthermore, fabricated eutectic can have the higher sensitivity to thermal neutron due to the high 6Li concentration compared to conventional single-crystal scintillators. Therefore, we have succeeded in developing a promising scintillator material.

DOI： 10.1109/TNS.2023.3278465

Scopus

Language：English   Publisher：Journal of Cancer Survivorship  

Background: Although rather favorable probabilities of return to work have been reported after allogeneic hematopoietic cell transplantation (allo-HCT), survivors often have difficulty continuing to work because of their immunocompromised status and diverse late effects after allo-HCT. We evaluated the incidence of and risk factors for recurrent sick leave in allo-HCT survivors after they initially returned to work. Methods: We targeted allo-HCT survivors who were employed at diagnosis, aged 20–64 at survey, and survived for ≥ 2 years without relapse. Of the 1904 survivors who were informed of the study, 1148 returned the questionnaire (60%), and 1048 eligible participants were included in the overall analysis. In the present study that considered recurrent sick leave after return to work, we targeted 896 participants who returned to work at least once after allo-HCT. Participants stated if they had recurrent sick leave after returning to work and its reasons, as well as associated patient-, HCT/HCT center–, and work-related factors and clinical events after allo-HCT. A logistic regression analysis was conducted to explore correlated factors for recurrent sick leave. Results: In survivors who returned to work, 30% required recurrent sick leave. The most frequent causes of recurrent leave were physical issues (72%), and analysis of free descriptions demonstrated that these were mainly associated with graft-versus-host disease, infection, or readmission. Other reasons included work-related issues such as gap between physical and working conditions. Multivariate analysis showed that cord blood transplantation, longer employment duration, and counseling from healthcare professionals were associated with a lower risk of recurrent leave. Readmission, immunosuppressant use, and symptoms involving the respiratory system, gut, and joints and muscles were associated with a higher risk. Conclusions: Our results drawn from a large cohort study should help healthcare professionals identify and assist at-risk patients. Multi-professional teams that provide continuous support and effective communication with the workplace are necessary to improve long-term outcomes after allo-HCT. Implications for Cancer Survivors: In order to continue working after the initial return to work, it is important to receive counseling from healthcare professionals and obtain reasonable accommodation from workplace.

DOI： 10.1007/s11764-022-01250-8

Scopus

PubMed

Language：Japanese   Publisher：The Japanese Society of Medical Imaging Technology  

<p>Compton cameras have the potential to become a novel imaging modality in nuclear medicine. One of the key issues in the medical application of Compton camera is the lack of performance measurement methods. In the case of SPECT and PET, there are standard performance measurement methods that are utilized in research and development of new imaging systems. Defining the standard performance measurement methods may facilitate research and development of a clinical Compton camera. We have organized an interdisciplinary research group and work towards developing performance measurement methods for medical Compton cameras. This report overviews this work.</p>

DOI： 10.11409/mit.41.117

CiNii Research

Publisher：Journal of Materials Chemistry C  

This research investigated the crystal chemical principles related to the incorporation of incompatible atoms into a garnet host lattice. These considerations might be used to guide and drive the design of new garnet compounds with novel properties. The strongly incompatible La atoms at the Lu sites of the Lu<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce host lattice served as a research model. This study showed the possibility of designing material properties by exploiting atom mismatches in a crystal lattice. Lu<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce0.075% crystals with increasing concentrations of La³⁺ ions were grown from the melt using the micro-pulling down method. The concentration of La³⁺ ions above 0.300 at% imposed physical and chemical boundary conditions on the crystallization process. The radial distributions of the chemical elements were studied as a function of the concentration of La³⁺ ions. It was revealed that La³⁺ codoping significantly reduced the cross-sectional fluctuation of the Ga and Al atoms. Persistent green-yellow luminescence due to the inter-configurational 5d → 4f transition of Ce³⁺ was observed after the blue-light excitation. The LuAGG:Ce0.075%,La0.015% phosphor showed long persistent luminescence for more than 14 h above 0.32 mcd m⁻², the detection limit of a human eye. The thermoluminescence glow curves revealed that the addition of La³⁺ ions increased the concentration of traps.

DOI： 10.1039/d3tc01304a

Scopus

Publisher：Japanese Journal of Applied Physics  

In this study, optical-guiding crystal scintillator (OCS) and bundled plates were fabricated. Considering the performance and melting point of halide scintillators and the softening point of glass, Tl:CsI was selected as the fiber core and borosilicate glass as the cladding. Thus, the fabricated OCS had a scintillator in the core and glass in the cladding. The scintillator was remelted and unidirectionally solidified to remove the voids in the OCS and form a single crystal. Consequently, the OCS served as a scintillator fiber with excellent optical-guiding performance and high sensitivity to γ- and X-rays. An OCS plate was also fabricated using bundles of OCSs with diameters of several tens of microns. The developed OCS plate is expected to be a high-resolution and high-sensitivity imaging plate because of its excellent optical-guiding performance.

DOI： 10.35848/1347-4065/acb3d1

Scopus

Publisher：Sedimentology  

Hemipelagites are widespread fine-grained sediments found from shelf margin to deep-water environments, and they are considered to have been formed as background sedimentation by vertical settling and slow lateral advection of clastic and biogenic fine-grained particles. Downflow variation in hemipelagic sedimentation, however, is not yet clearly understood, and was investigated in the lower Pleistocene Kiwada and Takamizo formations in the Kazusa forearc basin on the Boso Peninsula, Japan. Mapping of three tephra key beds enabled detailed correlation of two hemipelagite beds over a distance of ca 30 km from shelf-margin to basin-plain environments. The sedimentation rates decreased gradually in the downslope direction, but increased locally in response to turbidite sedimentation. This downslope variation indicates that hemipelagic sedimentation is not necessarily constant and varies in response to progradation and retrogradation of deep-water depositional systems, as well as additional input of fine-grained sediments from turbidity currents. In contrast, the grain size, magnetic susceptibility, clay-mineral composition, total organic carbon contents relative to total nitrogen contents (carbon/nitrogen), and δ¹³C values of organic carbon do not exhibit distinct downslope variation. This downslope consistency indicates that hemipelagites document temporal perturbations of geological and palaeoclimatic conditions in hinterlands, regardless of spatial and temporal variations in deep-water depositional environments. The concentrations of total organic carbon, total nitrogen and five biomarkers were lower values in turbiditic mudstones and hemipelagites that formed above a turbidite bed than in those of the other hemipelagites. This variation suggests that an additional supply of fine-grained sediments from turbidity currents likely diluted the organic matter in the hemipelagites. In addition, hemipelagites for which deposition was affected by turbidity currents exhibit slightly lower δ¹³C values, and may also document an additional contribution of terrestrial organic matter from turbidity currents.

DOI： 10.1111/sed.13055

Scopus

Language：English   Publisher：Cancer Science  

Nucleophosmin1 (NPM1) mutations are the most frequently detected gene mutations in acute myeloid leukemia (AML) and are considered a favorable prognostic factor. We retrospectively analyzed the prognosis of 605 Japanese patients with de novo AML, including 174 patients with NPM1-mutated AML. Although patients with NPM1-mutated AML showed a high remission rate, this was not a favorable prognostic factor for overall survival (OS); this is contrary to generally accepted guidelines. Comprehensive gene mutation analysis showed that mutations in codon R882 of DNA methyltransferase 3A (DNMT3A^R882 mutations) were a strong predicative factor indicating poor prognosis in all AML (p < 0.0001) and NPM1-mutated AML cases (p = 0.0020). Furthermore, multivariate analysis of all AML cases showed that DNMT3A^R882 mutations and the co-occurrence of internal tandem duplication in FMS-like tyrosine kinase 3 (FLT3-ITD), NPM1 mutations, and DNMT3A^R882 mutations (triple mutations) were independent factors predicting a poor prognosis related to OS, with NPM1 mutations being an independent factor for a favorable prognosis (hazard ratios: DNMT3A^R882 mutations, 1.946; triple mutations, 1.992, NPM1 mutations, 0.548). Considering the effects of DNMT3A^R882 mutations and triple mutations on prognosis and according to the classification of NPM1-mutated AML into three risk groups based on DNMT3A^R882/FLT3-ITD genotypes, we achieved the improved stratification of prognosis (p < 0.0001). We showed that DNMT3A^R882 mutations are an independent factor for poor prognosis; moreover, when confounding factors that include DNMT3A^R882 mutations were excluded, NPM1 mutations were a favorable prognostic factor. This revealed that ethnological prognostic discrepancies in NPM1 mutations might be corrected through prognostic stratification based on the DNMT3A status.

DOI： 10.1111/cas.15720

Open Access

Scopus

PubMed

Language：English  

Directionally solidified eutectics (DSEs) in Al2O3-based systems have been studied as high-temperature structural ceramics, also recently attracting attention as a phosphor screen for high-resolution radiation imaging. However, it is difficult to obtain uniform and thinly processed DSE in large areas. Here, we report a chemically deposited eutectic (CDE) of Lu3Al5O12 (LuAG)-Al2O3 using a laser-assisted chemical vapor deposition method. The Ce3+- doped LuAG lamella were epitaxially grew with an alpha-Al2O3 matrix on an r-cut sapphire substrate. The Ce3+: LuAG-alpha-Al2O3 CDE film exhibited green emissions due to the 5d-4f transitions of the Ce3+ center under UV light and alpha-/X-ray irradiations. The alpha-ray dose in the Ce3+:LuAG phase was estimated with Monte Carlo simulations to study a scintillation light yield of the CDE film. The X-ray radiograph of the semiconductor storage device was successfully obtained using a 15-mu m-thick Ce3+:LuAG-alpha-Al2O3 CDE film as an X-ray phosphor screen.

DOI： 10.1016/j.optmat.2023.113674

Scopus

CiNii Research

Publisher：Advanced Sensor Research  

Low-dimensional organic–inorganic hybrid manganese(II) halides are emerging as a highly promising class of candidate materials for X-ray imaging due to their excellent radioluminescence performance. Here, a red-emitting (Gua)<inf>2</inf>MnCl<inf>4</inf> (Gua = guanidine, CH<inf>6</inf>N<inf>3</inf>⁺) single crystal scintillator grown by a simple solution-processing method is reported. (Gua)<inf>2</inf>MnCl<inf>4</inf> crystallizes into a zero-dimensional (0D) crystal structure consisting of trimeric [Mn<inf>3</inf>Cl<inf>12</inf>]⁶⁻ units. It has a high PLQY of 76% and a large Stokes shift of 125 nm. (Gua)<inf>2</inf>MnCl<inf>4</inf> flexible scintillation screen demonstrates a decent X-ray detection limit of 145.3 nGy<inf>air</inf> s⁻¹ and a superior imaging resolution of 8 lp mm⁻¹. These results highlight the potential of low-dimensional red-emitting Mn-based hybrids for X-ray imaging applications.

DOI： 10.1002/adsr.202200083

Open Access

Scopus

Publisher：Physica Status Solidi Rapid Research Letters  

All-inorganic halide perovskites appear as a promising class of scintillators for radiation detection applications due to their excellent optoelectronic properties. Herein, a self-activated perovskite CsEuBr<inf>3</inf> single crystal is developed as an efficient X- and γ-ray scintillator. Single crystals of CsEuBr<inf>3</inf> are grown by the Bridgman method. The phase structure, stability, photophysics properties, and scintillation performance of CsEuBr<inf>3</inf> single crystals are studied. Under X-ray irradiation, its emission peaks at 445 and 510 nm, associated with Eu²⁺ 5d–4f and defect-related emission, respectively, are studied. Under ¹³⁷Cs gamma irradiation, it has a decent light yield of 22 000 ± 2000 photons MeV⁻¹ and an energy resolution of 6.2 ± 0.4% at 662 keV with a scintillation decay of 510 ns.

DOI： 10.1002/pssr.202200341

Scopus

Language：English   Publisher：ACS Chemical Biology  

(2,6)-Diamino-(5,7)-dihydroxyheptanoic acid (DADH), a non-proteinogenic amino acid, is converted to 1-azabicyclo[3.1.0]hexane ring-containing amino acids that are subsequently incorporated into ficellomycin and vazabitide A. The present study revealed that the sugar aminotransferase-like enzymes Fic25 and Vzb9, with a high amino acid sequence identity (56%) to each other, synthesized stereoisomers of DADH with (6S) and (6R) configurations, respectively. The crystal structure of the Fic25 complex with a PLP-(6S)-N²-acetyl-DADH adduct indicated that Asn45 and Gln197 (Asn205 and Ala53 in Vzb9) were located at positions that affected the stereochemistry of DADH being synthesized. A modeling study suggested that amino acid substitutions between Fic25 and Vzb9 allowed the enzymes to bind to the substrate with almost 180° rotation in the C5-C7 portions of the DADH molecules, accompanied by a concomitant shift in their C1-C4 portions. In support of this result, the replacement of two corresponding residues in Fic25 and Vzb9 increased (6R) and (6S) stereoselectivities, respectively. The different stereochemistry at C6 of DADH resulted in a different stereochemistry/orientation of the aziridine portion of the 1-azabicyclo[3.1.0]hexane ring, which plays a crucial role in biological activity, between ficellomycin and vazabitide A. A phylogenic analysis suggested that Fic25 and Vzb9 evolved from sugar aminotransferases to produce unusual building blocks for expanding the structural diversity of secondary metabolites.

DOI： 10.1021/acschembio.2c00823

Scopus

PubMed

Publisher：IEEE Transactions on Nuclear Science  

For using silicon photomultipliers (SiPMs) in space experiments, we conducted irradiation experiments of SiPMs with protons and iron ions. In particular, the relationship between leakage current and radiation dose was investigated under various irradiation conditions to determine techniques of mitigating damage caused by radiation. The leakage current was approximately proportional to dose; however, the proportionality constant did not significantly vary with irradiation conditions. The effects of annealing after irradiation tests indicated no substantial decrease in leakage current. Conversely, while the leakage current increased with dose, the SiPMs continued to operate even after 5 krad of irradiation, which corresponds to several years of radiation exposure in space at altitudes of 400-500 km. The results obtained from these irradiation tests are used to characterize a hard X-ray (>60 keV) detector for space-based applications. This detector couples an inorganic scintillator with a high light yield, such as CsI(Tl), to an SiPM.

DOI： 10.1109/TNS.2022.3162788

Scopus

Publisher：Applied Physics Express  

Scintillation properties of a flexible optical-guiding crystal scintillator with a thallium-doped CsI (Tl:CsI) crystal and borosilicate glass as the core and cladding, respectively, are reported. The as-fabricated optical-guiding crystal scintillator exhibits a light yield of 31,000 photons MeV⁻¹ under 662 keV γ-ray irradiation. The recrystallized sample is transparent and provides a higher light yield of 54,000 photons MeV^-1, which is comparable to that of single-crystal Tl:CsI. The decay times are 400 ns (28%) and 1,350 ns (72%). This material can serve as a scintillator fiber with high sensitivity to γ- and X-rays, high light yield, and energy discrimination.

DOI： 10.35848/1882-0786/acb891

Open Access

Scopus

Language：English   Publisher：Bone Marrow Transplantation  

A conditioning regimen is an essential prerequisite of allogeneic hematopoietic stem cell transplantation for patients with myelodysplastic syndrome (MDS). However, the optimal conditioning intensity for a patient may be difficult to establish. This study aimed to identify optimal conditioning intensity (reduced-intensity conditioning regimen [RIC] or myeloablative conditioning regimen [MAC]) for patients with MDS. Overall, 2567 patients with MDS who received their first HCT between 2009 and 2019 were retrospectively analyzed. They were divided into a training cohort and a validation cohort. Using a machine learning-based model, we developed a benefit score for RIC in the training cohort. The validation cohort was divided into a high-score and a low-score group, based on the median benefit score. The endpoint was progression-free survival (PFS). The benefit score for RIC was developed from nine baseline variables in the training cohort. In the validation cohort, the hazard ratios of the PFS in the RIC group compared to the MAC group were 0.65 (95% confidence interval [CI]: 0.48–0.90, P = 0.009) in the high-score group and 1.36 (95% CI: 1.06–1.75, P = 0.017) in the low-score group (P for interaction < 0.001). Machine-learning-based scoring can be useful for the identification of optimal conditioning regimens for patients with MDS.

DOI： 10.1038/s41409-022-01871-8

Scopus

PubMed

Language：Japanese   Publisher：The Japan Society of Applied Physics  

<p>  A radiation detector consisting of a scintillator and optical fiber has been proposed for the decommissioning of nuclear power plants to determine the dose rate in real-time. Inside the plant, gamma-ray and neutron emitting debris can remain, and the scintillator is required to have gamma-ray and neutron sensitivity. Moreover, red or near-infrared emission scintillators have the advantage to obtain higher sensitivity. In such demand, we have developed Li₂Hf(Br, I)₆ scintillator with an emission wavelength of around 650 nm under visible light excitation and X-ray excitation. The light outputs of this material excited by thermal neutron and 662-keV gamma-ray excitation were evaluated to be 18,000 photons/(thermal neutron) and 16,000 photons/MeV, respectively. Therefore, we found this material has a potential to apply such a real-time monitor.</p>

DOI： 10.11470/houshasen.48.2_49

CiNii Research

Publisher：Journal of Materials Chemistry C  

Cerium-doped rare-earth aluminum garnets represent an important class of scintillation and luminescent materials that are widely used in different technical fields, including medical imaging and solid-state white light sources, whose performances have to be further improved. One of the most effective tools for improving the light yield and timing characteristics of these materials is codoping with optically inactive ions. Herein, we investigate the Li⁺ incorporation, as well as defect formation processes imposed by X-ray and UV irradiation, in Li⁺-codoped Y<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce garnet scintillation crystals with the use of electron paramagnetic resonance (EPR), ⁷Li nuclear magnetic resonance, and thermally stimulated luminescence (TSL) methods. The EPR study showed that the Ce³⁺ content in the Li⁺-codoped crystals does not depend visibly on the Li concentration. The EPR spectra of X-ray-irradiated Li⁺-codoped YAG crystals revealed the presence of both isolated O⁻ centers (a hole trapped at the oxygen ion) and O⁻ centers stabilized by the neighboring Li⁺ ions. The latter centers are responsible for the TSL peak at 320 K. Our data also show that at low Li concentrations in the melt, the Li⁺ ions mainly substitute for Y³⁺ ions. However, at high Li⁺ ion concentrations (∼1 at% in melt), the Li⁺ ions also substitute for Al³⁺ ions. A strong increase in the oxygen vacancy concentration in the Li⁺-codoped crystals suggests that oxygen vacancies serve as effective compensators for the negative excess charge introduced into the crystal lattice by Li⁺ ions, thus suppressing the Ce³⁺ → Ce⁴⁺ conversion process, which plays an important role in the acceleration of the scintillation decay. The obtained data suggest that the decrease in a slow component in the scintillation decay of the Li⁺ ion-codoped crystals is caused, at least partly, by the redistribution of trapped charge carriers to more thermally stable centers.

DOI： 10.1039/d2tc04520f

Scopus

Language：Japanese   Publisher：Japan Radioisotope Association  

<p>High effective atomic-numbers (Z_eff) and light outputs are required for gamma-ray scintillator, and we have developed novel materials such as Cs₂HfI₆ (Z_eff:58) and Ce³⁺-doped (Gd, La)₂Si₂O₇ (Z_eff:56) with high light outputs of approximately 64,000 photons/MeV and 50,000–60,000 photons/MeV, respectively.</p>

DOI： 10.3769/radioisotopes.71.255

Open Access

CiNii Research

Publisher：MRS Advances  

Cyclo-olefin polymer (COP) has attracted much attention as substrate material for microfluidic devices because of its excellent optical properties, processability, and lower cost than glass materials. We have previously reported surface modification using water vapor plasma as a method of bonding COP substrates at low temperature. In this study, water feeding and bonding strength of this method was investigated using a microfluidic device equipped with fluid leak detectors. Water was fed by capillary flow in microchannels bonded at room temperature. Water leak was visually detected by the detectors, using an optical microscope. The withstanding pressure was 200 kPa or higher.

DOI： 10.1557/s43580-022-00346-8

Scopus

Language：English   Publisher：Journal of Cancer Survivorship  

Purpose: To characterize the issues regarding work and employment specific to allogeneic hematopoietic cell transplantation (allo-HCT) survivors, we conducted a nationwide cross-sectional questionnaire survey. Methods: We targeted allo-HCT survivors employed at diagnosis, aged 20–64 at survey, and survived ≥2 years without relapse. The questionnaire included the timing of and reasons for resignation (termination of employment contract), and patient-related, HCT-related, work-related, and HCT center-related factors. Results: A total of 1048 eligible participants were included in the analysis (response rate, 60%). The median time after allo-HCT was 5 years (range, 2–30) at the time of survey. After diagnosis, 41% of participants resigned from work throughout the course of treatment. The most frequent timing of the first resignation was “after discharge post-HCT” (46%), followed by “from diagnosis to initial treatment” (27%). Factors significantly associated with resignation included female gender, older age, and part-time employment. Favorable factors included the presence of occupational health staff at the workplace, employment of ≥10 years, and self-employed/freelance. After resignation, the overall incidence of return to work with some accommodations was 76% at 5 years after HCT, but it was 52% without any accommodation. Conclusions: Overall, the rate of resignation was 41%, and the most frequent timing of resignation was after discharge post-HCT, accounting for approximately half of the resignations (46%). Workplace accommodations increased the rate of return to work from 52% to 76%. Implications for Cancer survivors: Early detection of employment-related concerns and support throughout the treatment process are necessary for patients receiving allo-HCT.

DOI： 10.1007/s11764-021-01092-w

Scopus

PubMed

Language：English   Publisher：Journal of the American Chemical Society  

Natural products containing an aziridine ring, such as mitomycin C and azinomycin B, exhibit antitumor activities by alkylating DNA via their aziridine rings; however, the biosynthetic mechanisms underlying the formation of these rings have not yet been elucidated. We herein investigated the biosynthesis of vazabitide A, the structure of which is similar to that of azinomycin B, and demonstrated that Vzb10/11, with no similarities to known enzymes, catalyzed the formation of the aziridine ring via sulfate elimination. To elucidate the detailed reaction mechanism, crystallization of Vzb10/11 and the homologous enzyme, AziU3/U2, in the biosynthesis of azinomycin B was attempted, and the structure of AziU3/U2, which had a new protein fold overall, was successfully determined. The structural analysis revealed that these enzymes adjusted the dihedral angle between the amino group and the adjacent sulfate group of the substrate to almost 180° and enhanced the nucleophilicity of the C6-amino group temporarily, facilitating the S<inf>N</inf>2-like reaction to form the aziridine ring. The present study reports for the first time the molecular basis for aziridine ring formation.

DOI： 10.1021/jacs.2c07243

Scopus

PubMed

Publisher：Optical Materials  

Mg²⁺-codoped Y<inf>0.6</inf>Gd<inf>2.4</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce (YGAGG:Ce,Mg) single crystal was grown by the Czochralski method and its luminescence and scintillation properties were investigated. Temperature dependence of radioluminescence (RL) yield and photoluminescence (PL) decay time was measured, and activation energy of thermal ionization process was determined from temperature-dependent PL decay time measurement. YGAGG:Ce,Mg exhibited high X-ray excited RL yield almost 5 times higher than BGO reference scintillator. Its light yield of 41,500 ph/MeV and scintillation decay times of 12 ns (2%) + 52 ns (65%) + 207 ns (33%) were measured under excitation with 662 keV γ rays from ¹³⁷Cs source. Afterglow and thermally stimulated luminescence characteristics are also investigated.

DOI： 10.1016/j.optmat.2022.112662

Scopus

Publisher：Optical Materials X  

In this study, Tl:CsI/CsCl/KCl ternary eutectic scintillators were grown using the vertical Bridgman–Stockbarger method by unidirectional solidification. The CsI and KCl phases were elongated along the growth direction, based on backscattered electron imaging (BEI) observations. The Tl:CsI scintillator phase grew as a matrix, which can be used to create optical waveguides for scintillation light. The expected Tl⁺ emission peak was observed at 550 nm under X-ray excitation. This emission was attributed to the self-trapped excitons perturbed by TI⁺ in Tl:CsI. The decay time of the Tl:CsI/CsCl/KCl eutectic was 285 ns, and its light output was estimated to be 10,800 photons/MeV.

DOI： 10.1016/j.omx.2022.100159

Open Access

Scopus

Publisher：Japanese Journal of Applied Physics  

The influence of the reflected waves at the bonding boundary on the resonance waveform and temperature characteristics was investigated using α-quartz (QZ). The double-layered resonator specimen was fabricated using 129.55°Y-and 0°Y-cut QZ substrates with the thickness ratio x = 0.520. The temperature characteristic of the 1st and 2nd resonance modes at the range from 100 °C to 300 °C was deviated from the calculated values estimated by the equations considering thickness ratio and electric flux density ratio proposed in the previous work. Considering the phase matching conditions, it was clarified that the reflected waves at the bonding boundary are in phase in the lower acoustic impedance substrate and out of phase in the other substrate for the 1st mode, so the temperature characteristics are mainly dominated by that of the lower acoustic impedance substrate. In contrast, these relationships are reversed for the 2nd mode.

DOI： 10.35848/1347-4065/ac4a03

Scopus

Language：English   Publisher：Transplantation and Cellular Therapy  

Even in the era of high-intensity chemotherapy, disease recurrence remains a major cause of treatment failure in adult patients with Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia (Ph-negative B-ALL). For patients who achieved second complete remission (CR2) with salvage chemotherapy, allogeneic hematopoietic stem cell transplantation (allo-HSCT) could be the best curative treatment. However, limited data are available on the outcomes of allo-HSCT for adult Ph-negative B-ALL in CR2 in the high-intensity chemotherapy era. We evaluated the transplantation outcomes of adult patients with Ph-negative B-ALL in CR2 compared with those in CR1. We also clarified the prognostic factors among adult allo-HSCT recipients with Ph-negative B-ALL in CR2. We conducted a nationwide retrospective study using the data form Japanese transplant registry database. Patients aged ≥16 years and underwent their first allo-HSCT between 2003 and 2017 were included. The 3-year overall survival (OS) rate of the patients in CR2 (n = 382) was significantly lower than that in first complete remission (n = 1375) (51.8% versus 68.1%; P < .001), accompanied by a higher relapse rate (34.2% versus 17.6% at 3 years; P < .001). In a multivariate analysis among CR2 patients, time from diagnosis to allo-HSCT (≤2 years) was a significant factor for OS (hazard ratio [HR] 1.87; P < .001) and relapse (HR = 1.88; P < .001), whereas age at allo-HSCT (≥30 years) was a significant factor for OS (HR = 2.10, P < .001) and nonrelapse mortality (HR = 2.68; P < .001). By assigning a score of 1 to each factor, the 3-year OS rate of CR2 patients significantly stratified: 70.7% in patients with score 0, 56.4% with score 1, and 28.4% with score 2 (P < .001). The survival outcomes of allo-HSCT in adult Ph-negative B-ALL patients in CR2 were inferior to those in CR1 in the high-intensity chemotherapy era, mainly because of the higher relapse rate. Among the CR2 patients, the short time between diagnosis and allo-HSCT was a significant risk factor for disease recurrence and overall mortality. Better disease control with novel treatment strategies may be needed for early relapse. In addition, the nonrelapse mortality rate in patients over 30 years of age was particularly high among CR2 patients, suggesting the need for improved supportive care for these patients. Further studies are warranted on the outcomes of allo-HSCT after achieving CR2 with novel drugs, such as inotuzumab ozogamicin and blinatumomab.

DOI： 10.1016/j.jtct.2022.03.017

Scopus

PubMed

Language：English   Publisher：Transplantation and Cellular Therapy  

There are limited data comparing myeloablative conditioning with fludarabine/busulfan (Flu/Bu4) and reduced-intensity conditioning with fludarabine/busulfan (Flu/Bu2) in patients with myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed nationwide registry data and compared the outcomes of adult patients with MDS receiving Flu/Bu4 and Flu/Bu2 by propensity score (PS) matching. Patients who met the following criteria were eligible for enrollment: (1) age ≥16 years; (2) diagnosis of de novo MDS; (3) first allo-HSCT between 2006 and 2018; (4) related bone marrow transplantation (BMT) or peripheral blood stem cell transplantation from an HLA-matched donor, unrelated BMT from an HLA-matched or HLA-1 allele–mismatched donor, or unrelated cord blood transplantation; and (5) receiving Flu/Bu4 or Flu/Bu2 as a conditioning regimen. Flu/Bu4 comprised intravenous busulfan (total dose, 12.8 mg/kg) combined with fludarabine (total dose, 125–180 mg/m²). Flu/Bu2 comprised intravenous busulfan (total dose, 6.4 mg/kg) combined with the same dose of fludarabine. To minimize selection bias and confounding factors, we performed a propensity score (PS)-matched analysis. The primary endpoint was overall survival (OS) after allo-HSCT. A total of 3386 patients with de novo MDS underwent their first allo-HSCT between 2006 and 2018. Among them, 202 patients were assigned each to the Flu/Bu4 and Flu/Bu2 groups after PS-matched analysis. The median age was 61 (interquartile, 57-65) years. The 3-year OS rates were 44.8% (95% confidence interval [CI], 37.1–52.1%) and 46.9% (95% CI, 39.2–54.2%) in the Flu/Bu4 and Flu/Bu2 groups, respectively (P = .67). The 3-year rates of graft-versus-host disease (GVHD)–free survival, relapse-free survival (GRFS) were 28.8% (95% CI, 22.2–35.7%) and 33.0% (95% CI, 26.2–40.0%), respectively (P = .36). The 3-year cumulative incidence rates of relapse were 28.9% (95% CI, 22.6–35.6%) and 30.0% (95% CI, 23.6–36.6%), respectively (P = .47). The 3-year cumulative incidence rates of non-relapse mortality (NRM) were 28.2% (95% CI, 21.7–35.0%) and 27.1% (95% CI, 20.6–33.9%), respectively (P = .60). The 100-day cumulative incidence rate of grade II–IV acute GVHD was significantly higher in the Flu/Bu4 group than in the Flu/Bu2 group (41.7% [95% CI, 34.8%–48.4%] versus 29.3% [95% CI, 23.2%-35.7%], P = 0.012). To identify patients who had more favorable outcomes with 1 of the 2 regimens, we compared the outcomes between the 2 groups after stratifying by age, hematopoietic cell transplantation-comorbidity index, cytogenetic risk, disease status at allo-HSCT, stem cell source, and donor type. OS, GRFS, relapse, and NRM did not differ between the 2 groups in any subgroup analyses. There were no significant interactions between the choice of conditioning regimens and any other factors. There are no differences in survival between Flu/Bu4 and Flu/Bu2, although our study population was highly selected by PS matching. Data from more patients and prospective studies are needed to determine the optimal intensity of conditioning regimens in patients with MDS.

DOI： 10.1016/j.jtct.2022.03.011

Scopus

PubMed

Language：English  

MeV gamma-rays provide a unique window for the direct measurement of line emissions from radioisotopes, but observations have made little significant progress since COMPTEL on board the Compton Gamma-ray Observatory (CGRO). To observe celestial objects in this band, we are developing an electron-tracking Compton camera (ETCC) that realizes both bijective imaging spectroscopy and efficient background reduction gleaned from the recoil-electron track information. The energy spectrum of the observation target can then be obtained by a simple ON–OFF method using a correctly defined point-spread function on the celestial sphere. The performance of celestial object observations was validated on the second balloon SMILE-2+ , on which an ETCC with a gaseous electron tracker was installed that had a volume of 30 × 30 × 30 cm³. Gamma-rays from the Crab Nebula were detected with a significance of 4.0σ in the energy range 0.15–2.1 MeV with a live time of 5.1 hr, as expected before launch. Additionally, the light curve clarified an enhancement of gamma-ray events generated in the Galactic center region, indicating that a significant proportion of the final remaining events are cosmic gamma-rays. Independently, the observed intensity and time variation were consistent with the prelaunch estimates except in the Galactic center region. The estimates were based on the total background of extragalactic diffuse, atmospheric, and instrumental gamma-rays after accounting for the variations in the atmospheric depth and rigidity during the level flight. The Crab results and light curve strongly support our understanding of both the detection sensitivity and the background in real observations. This work promises significant advances in MeV gamma-ray astronomy.

DOI： 10.3847/1538-4357/ac6103

Open Access

Scopus

CiNii Research

Publisher：Japanese Journal of Applied Physics  

A 6LiBr/CeBr3 eutectic thermal-neutron scintillator, with a high 6Li concentration, was developed using the vertical Bridgman method. The grown eutectic contained an 6Li molar ratio of 35%, which is higher than those of the commercial neutron scintillators such as Ce:LiCaAlF6 and Ce:Cs2LiYCl6. Furthermore, it showed optical transparency and a lamellar eutectic structure elongating along the growth direction. The synthesized eutectic showed emission peaks at 360 and 380 nm, originating from the Ce3+ 5d-4f transition in the CeBr3 scintillation phase. The scintillation performance of 6LiBr/CeBr3 was evaluated under X-ray, γ-ray, and neutron irradiation to corroborate its neutron detection potential.

DOI： 10.35848/1347-4065/ac4076

Scopus

Publisher：Optical Materials X  

In this study, it was demonstrated that Zn<inf>3</inf>Ta<inf>2</inf>O<inf>8</inf> crystals containing zinc oxide with high vapor pressure can grow in melt by the shielded arc melting method. The radiation response characteristics of the crystals were evaluated. The grown crystals showed an emission peak at 410 nm, ascribed to self-trapped excitation, Ta⁴⁺–O²⁻. The full width at half maximum of the X-ray rocking curve was 655 arcsec. The light output under 662 keV gamma-ray irradiation of Zn<inf>3</inf>Ta<inf>2</inf>O<inf>8</inf> was approximately 4,700 photons/MeV. The decay time was 17.3 μs? Thus, the shielded arc melting method was shown to be a quick and economic growth technique for the survey of new scintillator materials containing high-vapor-pressure starting components.

DOI： 10.1016/j.omx.2022.100149

Open Access

Scopus

Publisher：Japanese Journal of Applied Physics  

In this study, a large-size eutectic scintillator of Tb-doped BaCl2/NaCl/KCl was grown using the Czochralski (Cz) and halide vertical Bridgman methods (H-VB). The suitability of these two growth methods for growing the eutectic was compared. Finally, 1 inch diameter eutectic bulks were obtained using the H-VB method. The Tb3+-derived strongest intensity peak at approximately 550 nm was observed by X-ray irradiation. An approximately 3 × 3 mm transparent eutectic wafer was cut and polished from the grown eutectic bulk. An imaging test using α-ray was performed using the grown eutectic, a fiber optic plate, and an electron-multiplying CCD camera. The resolution performance for radiation-imaging applications was evaluated.

DOI： 10.35848/1347-4065/ac3b23

Scopus

Publisher：Journal of Crystal Growth  

Ce-doped LaCl<inf>3</inf>/AECl<inf>2</inf> (AE = Mg, Ca, Sr) system eutectics were explored. Ce-doped LaCl<inf>3</inf>/ AECl<inf>2</inf> (AE = Mg, Ca, Sr) eutectics were grown using the Bridgman–Stockbarger method in quartz ampoules. In the case of AE = Mg, Ca, eutectics with submicron-diameter phase-separated scintillator fibers (PSSFs) structure were observed. In the case of AE = Sr sample, a solid solution of La<inf>0.708</inf>Sr<inf>0.292</inf>Cl<inf>2.708</inf> was observed. The plate sample from the grown eutectics has some transparency. The grown eutectic structure showed a mixture of rods and plates shape. This mixed structure was aligned with a length of around 100–400 μm. The Ce:LaCl<inf>3</inf>/CaCl<inf>2</inf> eutectic showed 345 nm emission ascribed to Ce³⁺ 4f-5d transition under X-ray excitation. The Ce:LaCl<inf>3</inf>/CaCl<inf>2</inf> sample resulted in the highest light output of 9,000 photon/MeV, which is comparable to the previously reported eutectic scintillator Ce:GdAlO<inf>3</inf>/α-Al<inf>2</inf>O<inf>3</inf>, 9500 photon/MeV. Scintillation decay time of the Ce:LaCl<inf>3</inf>/CaCl<inf>2</inf> sample under 662 keV gamma-ray excitation was 26.8 ns (26%) and 282 ns (74%).

DOI： 10.1016/j.jcrysgro.2022.126549

Scopus

Publisher：Journal of Alloys and Compounds  

The undoped, Mg²⁺ doped, Ce³⁺ doped as well as Mg²⁺:Ce³⁺ codoped Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> crystals were grown from the melt by the micro-pulling down method. Ce³⁺ and Mg²⁺ ions were codoped in a wide concentration range. A study of Mg²⁺ ion concentration effect on the luminescence and scintillation properties as well as segregation of atoms and defects creation processes were carried out. Mg²⁺ doping in Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> led to the creation of O<inf>O</inf>^• defects localized next to Mg²⁺ sites due to charge imbalance compensation. Consequently, neutral (Mg<inf>Ga/Al/Gd</inf>O<inf>O</inf>)^x defects were formed. In Ce³⁺ doped crystals, Mg²⁺ codoping changed the valence state from Ce³⁺ to Ce⁴⁺ to maintain charge neutrality. Hence, additional neutral (Ce<inf>Gd</inf>^•-Mg<inf>Ga/Al/Gd</inf>′)^x and (Ce<inf>Gd</inf>-Mg<inf>Ga/Al/Gd</inf>O<inf>O</inf>)^x defects appeared. Moreover, Mg²⁺ induced charge imbalance in GAGG crystal might also be compensated by the formation of oxygen vacancies (V<inf>O</inf>^••). The Mg²⁺ ions imposed defects deteriorated the segregation of atoms. Accordingly the radial inhomogeneity of the crystals was diminished. The presence of stable Ce⁴⁺ and defects imposed by Mg²⁺ ions codoping were proved by absorption, photoluminescence, and scintillation decay time analysis. Hence, Mg²⁺ codoping resulted in quenching of the Ce³⁺ luminescence, acceleration of scintillation response, reduction of light yield, and thermally stimulated luminescence. The mechanism explaining a strong luminescence quenching with increasing Mg²⁺ ions concentration was proposed.

DOI： 10.1016/j.jallcom.2022.164154

Scopus

Publisher：Journal of Crystal Growth  

La<inf>2</inf>Hf<inf>2</inf>O<inf>7</inf> crystals with a melting point of ∼2418 °C were grown by the micro-pulling-down method using a W crucible and deoxygenated ZrO<inf>2</inf> insulators. A La<inf>2</inf>Hf<inf>2</inf>O<inf>7</inf> crystal grown at a rate of 0.07 mm/min (LHO[0.07 mm/min]) showed a high transparency without any visible cracks and inclusions, while a La<inf>2</inf>Hf<inf>2</inf>O<inf>7</inf> crystal grown at a rate of 2.00 mm/min had some cracks. The LHO[0.07 mm/min] crystal had a transmittance of over 70% in the wavelength range of 450–800 nm. The X-ray rocking curve of the LHO[0.07 mm/min] crystal showed a symmetric sharp peak with a full width at half maximum of 138 arcsec. The Laue image revealed that the grown crystals were single crystals.

DOI： 10.1016/j.jcrysgro.2022.126547

Scopus

Publisher：Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment  

In this study, Ce:⁶LiBr/LaBr<inf>3</inf> eutectic with a high Li concentration was developed as a novel thermal neutron scintillator. Ce served as an activator for the LaBr<inf>3</inf> phase, and Ce:⁶LiBr/LaBr<inf>3</inf> eutectics were grown via the vertical Bridgman method in quartz ampoules (inner diameter = 4 mm). In the eutectic, the ⁶LiBr phase worked as the neutron capture phase by the ⁶Li (n, a) ³H reaction, and Ce:LaBr<inf>3</inf> worked as the scintillator phase. The Ce:⁶LiBr/LaBr<inf>3</inf> eutectic exhibited a lamellar eutectic structure and optical transparency, as well as 350 and 380 nm emission due to Ce³⁺ 5d-4f transition. The light yield under neutrons excitation was estimated to be 74000 photons/neutron. The scintillation decay time was 18.7 ns.

DOI： 10.1016/j.nima.2022.166384

Scopus

Publisher：Journal of Crystal Growth  

Phenanthrene crystals were grown by the self-seeding vertical Bridgman technique as a neutron scintillation material and their luminescence properties were evaluated. As-grown crystals had no secondary phases from the results of the powder X-ray Diffraction and Fourier transform infrared spectrometer measurements. The radioluminescence emission spectrum had a peak at 408 nm and its profile was similar to that of the photoluminescence emission spectrum. The relative light yield under 5.5-MeV alpha-ray was 1.15 times higher than that of lithium glass GS-20. The light yield of phenanthrene under 662 keV gamma-ray is estimated to be 38 ± 2% of NaI:Tl. The scintillation decay time under neutron excitation was estimated to be 7.30 ± 0.14 ns.

DOI： 10.1016/j.jcrysgro.2021.126494

Scopus

Language：English   Publisher：Supportive Care in Cancer  

Purpose: Advances in allogeneic hematopoietic cell transplantation (allo-HCT) have resulted in a growing number of transplant survivors; however, long-term survivors are at risk of developing late complications, and published guidelines recommend screening of this population. We conducted a single-center prospective study to evaluate the adherence to and usefulness of recommended screenings at a long-term follow-up (LTFU) clinic. Methods: We included consecutive patients who received allo-HCT at our center from 2014, as well as post-HCT patients visiting our outpatient clinic. Visits and screenings were planned at 3 months, 6 months, and 1 year after allo-HCT, and annually thereafter. Outcomes were reported by physicians including the incidence of findings at each screening that led to interventions. Results: Among the 216 participants, 95% visited the LTFU clinic, and 94% completed planned screenings. However, the rate of secondary cancer screenings targeting high-risk subjects was lower (38% to 68%). The overall percentage of screening results leading to interventions was 4.5%, with higher percentages (> 10%) for bone density testing, ophthalmological examinations, dental assessment, upper gastrointestinal endoscopy, and colonoscopy, with two patients diagnosed with secondary cancers. Conclusions: Although the overall screening rate was high, it should be possible to improve the detection rate of late complications by decreasing screening failures, especially the screening for secondary cancers limited for high-risk survivors. A nationwide effort to educate HCT survivors and health practitioners using standardized nationwide LTFU tools may be effective, along with the development of institutional, local, and nationwide networks to maintain effective follow-up systems.

DOI： 10.1007/s00520-021-06698-5

Scopus

PubMed

Publisher：Physica Status Solidi B Basic Research  

Some specifics of spectroscopic and laser properties of Yb³⁺ dopant are shown in Yb³⁺-doped Lu<inf>2</inf>O<inf>3</inf> cubic sesquioxide transparent ceramics, a very important laser material, fabricated by Akio Ikesue using the method based on solid-state mixing of oxides and sintering by hot isostatic pressing (HIP) technique. For instance, despite the simplicity of Yb³⁺ electronic configuration, it is emphasized that a lot of precautions need to be considered during the evaluation and the assignment of Yb³⁺ experimental data in this sample and also in all Yb³⁺-doped materials. First, we focus our discussion on the position of ²F<inf>7/2</inf> (ground state) and ²F<inf>5/2</inf> (excited state) Stark levels of the most populated C<inf>2</inf> symmetry site, and on the presence of the magnetic dipole transitions from the C<inf>3i</inf> (S<inf>6</inf>) inversion symmetry site. Then, we point out the strong influence of the self-trapping and the self-quenching processes on the measurement of the ²F<inf>5/2</inf>(5) upper level decay time which needs the pin-hole method. Finally, we comment on the spectrum of the tuneable laser emission behaviour near 1033 nm with respect to the losses of the laser cavity without the laser emission near 1080 nm, as observed in other laser materials.

DOI： 10.1002/pssb.202100521

Scopus

Publisher：Journal of Physics Conference Series  

The topological information of Cherenkov light emitted from low energy electron was directly measured by HUNI-ZICOS detector. A 1.484 MeV electron with fixed direction to the center of hemispherical surface of the detector was generated by Compton back scattering with 100 degree from ⁸⁸Y 1.836 MeV gamma. The observed averaged angle of Cherenkov light emitted from this electron was clustered around 40 degree assuming the vertex position to be at the center of truncated icosahedron photomultiplier jig. It was not Cherenkov angle around 47 degree as obtained by old simulation and the vertex to be the center of light yield for hitted photomultiplier. According to the HUNI-ZICOS simulation, the averaged angle of Cherenkov light was also clustered around 40 degree. On the other hands, the simulated averaged angle of scintillation was clustered around 49 degree, which is consistent with the averaged value of angle between the direction to center of hemisphere surface and each photomultiplier from the center of the jig. The obtained hitmap seemed to have same non flat structure as that of simulation due to Cherenkov ring. This is an evidence that Cherenkov lights emitted from 1.484 MeV electron should really have their topology. Therefore, we concluded that we will be able to reduce ²⁰⁸Tl background using the averaged angle for ⁹⁶Zr neutrinoless double beta decay search.

DOI： 10.1088/1742-6596/2156/1/012116

Open Access

Scopus

Publisher：Journal of Crystal Growth  

In this study, Tb:BaCl<inf>2</inf> and NaCl/KCl ternary eutectics were grown using quartz ampoules via the vertical Bridgman–Stockbarger method. Each crystal phase had a polygonal columnar shape with a length of 300 µm along the growth direction. The Tb:BaCl<inf>2</inf> scintillator phase grew in the columnar phase. The BaCl<inf>2</inf> scintillator phase is expected to make optical waveguides of the scintillation light. The expected Tb³⁺ emission peak was observed at approximately 360–630 nm under X-ray irradiation. This emission is mainly attributed to the Tb³⁺⁵D<inf>4</inf>→⁷F<inf>6</inf>, ⁷F<inf>6</inf>, ⁷F<inf>5</inf>, ⁷F<inf>4</inf>, and ⁷F<inf>3</inf> transitions and BaCl<inf>2</inf> host emission transition. The photoluminescence decay times of the Tb:BaCl<inf>2</inf>/NaCl/KCl eutectics was 0.49 ms (7.5%) and 6.64 ms (92.5%).

DOI： 10.1016/j.jcrysgro.2021.126467

Scopus

Publisher：IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control  

The effect of the difference in the thickness ratio of the double-layered thickness-shear resonator on the temperature characteristics of the resonance frequency was investigated using a Ca₃TaGa₃Si₂O₁₄ (CTGS) single crystal. Three specimens with thickness ratios of <inline-formula> <tex-math notation="LaTeX">${x} =0.25$ </tex-math></inline-formula>, 0.33, and 0.50 were prepared using <inline-formula> <tex-math notation="LaTeX">$122^{\circ } ~{Y}$ </tex-math></inline-formula>- and <inline-formula> <tex-math notation="LaTeX">$171^{\circ }~{Y}$ </tex-math></inline-formula>-cut CTGS substrates. For the specimens with <inline-formula> <tex-math notation="LaTeX">${x} =0.25$ </tex-math></inline-formula> and 0.33, the temperature characteristics varied depending on the order of the resonance mode. For the specimen with <inline-formula> <tex-math notation="LaTeX">${x} =0.50$ </tex-math></inline-formula>, on the other hand, almost the same temperature characteristics were observed regardless of the order of the resonance mode. To interpret this phenomenon, a new equation for predicting the temperature characteristics of the fundamental mode (first mode) for the double-layered resonator was created using the electric flux density ratio generated in the two substrates. The expected values using this equation were in good agreement with the result of the first mode temperature characteristics.

DOI： 10.1109/TUFFC.2021.3121782

Scopus

Language：English   Publisher：Blood Advances  

Mutations of CCAAT/enhancer–binding protein alpha (CEBPAmu) are found in 10% to 15% of de novo acute myeloid leukemia (AML) cases. Double-mutated CEBPA (CEBPAdm) is associated with a favorable prognosis; however, single-mutated CEBPA (CEBPAsm) does not seem to improve prognosis. We investigated CEBPAmu for prognosis in 1028 patients with AML, registered in the Multi-center Collaborative Program for Gene Sequencing of Japanese AML. It was found that CEBPAmu in the basic leucine zipper domain (bZIP) was strongly associated with a favorable prognosis, but CEBPAmu out of the bZIP domain was not. The presence of CEBPAmu in bZIP was a strong indicator of a higher chance of achieving complete remission (P, .001), better overall survival (OS; P, .001) and a lower risk of relapse (P, .001). The prognostic significance of CEBPAmu in bZIP was also observed in the subgroup with CEBPAsm (all patients: OS, P 5 .008; the cumulative incidence of relapse, P 5 .063; patients aged #70 years and with intermediate-risk karyotype: OS, P 5 .008; cumulative incidence of relapse, P 5 .026). Multivariate analysis of 744 patients aged #70 years showed that CEBPAmu in bZIP was the most potent predictor of OS (hazard ratio, 0.3287; P, .001). CEBPAdm was validated as a cofounding factor, which was overlapping with CEBPAmu in bZIP. In summary, these findings indicate that CEBPAmu in bZIP is a potent marker for AML prognosis. It holds potential in the refinement of treatment stratification and the development of targeted therapeutic approaches in CEBPA-mutated AML.

DOI： 10.1182/bloodadvances.2021004292

Open Access

Scopus

PubMed

Publisher：Proceedings of the International Display Workshops  

ZnO films were deposited on sapphire substrates by magnetron sputtering and annealed to produce zinc aluminate (ZnAl2O4) deep ultraviolet emitting phosphor thin films by mutual thermal diffusion between film and substrate. Etching was applied to the annealed samples to change the film thickness of ZnAl2O4. the samples after etching were subjected to emission characteristics evaluation by cathodoluminescence (CL) and crystal structure analysis by X-ray diffraction (XRD), and elemental mapping by field emission-scanning electron microscope analysis (FE-SEM) to estimate the range where Zn was distributed and the distribution of high quality emitting layer.

Scopus

Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.77.1.0_405

Open Access

CiNii Research

Publisher：Proceedings of Science  

The topological information (averaged angle) of Cherenkov light was measured by UNI-ZICOS detector. We have retuned the pulse shape discrimination for a selection of the photomultiplier which receives Cherenkov light for Hamamatsu H3164-12, and have developed a method of the vertex reconstruction. An averaged angle for fixed energy fixed direction electron generated by Compton scattering from ⁸⁸Y was used for the validity checking of the selection of PMT, and the obtained peak was found around 50 degree which was reproduced by Monte Carlo simulation. A pseudo background events of simultaneous beta and Compton electron scattered by gamma from the decay of ²⁰⁸Tl was simulated by ⁶⁰Co β source. Obtained data indicated that the averaged angle of simultaneous beta with E ≤ 1.48 MeV plus gamma events should have a peak around 60 degree, and the value is different from 48 degree for an usual electron. In conclusion, the averaged angle will be able to use as a reduction method for ²⁰⁸Tl beta decay backgrounds even though they have an energy around 3.35 MeV which is Q-value of ⁹⁶Zr neutrinoless double beta decay.

Scopus

Publisher：Journal of Crystal Growth  

La<inf>2</inf>Zr<inf>2</inf>O<inf>7</inf> crystals with a melting point of 2283 °C are grown via the micro-pulling-down (μ-PD) method using Mo and W crucibles to expand the possibility of material research of functional single crystals with high melting points by the μ-PD method. La<inf>2</inf>Zr<inf>2</inf>O<inf>7</inf> crystals grown using Mo and W crucibles under an Ar + 3% H<inf>2</inf> atmosphere are composed of a La<inf>2</inf>Zr<inf>2</inf>O<inf>7</inf> main phase, which includes Mo and W. However, a La<inf>2</inf>Zr<inf>2</inf>O<inf>7</inf> crystal without W can be grown under an Ar atmosphere using the μ-PD method using a W crucible and deoxygenated ZrO<inf>2</inf> insulators. After post-annealing in air at 1000 °C, the La<inf>2</inf>Zr<inf>2</inf>O<inf>7</inf> crystal without W becomes colorless and transparent, indicating a transmittance exceeding 70% in wavelengths ranging from 450 to 800 nm.

DOI： 10.1016/j.jcrysgro.2021.126357

Scopus

Language：English   Publisher：Bone Marrow Transplantation  

Myeloablative conditioning with fludarabine/busulfan (Flu/Bu4) prior to allogeneic hematopoietic stem cell transplantation (allo-HSCT) is effective for acute myeloid leukemia. However, the effectiveness of Flu/Bu4 for myelodysplastic syndrome (MDS) remains poorly understood. Therefore, we retrospectively analyzed nationwide registry data in Japan from 2006 to 2018 and compared transplant outcomes of adult MDS patients receiving Flu/Bu4 and busulfan/cyclophosphamide (Bu4/Cy) using propensity score (PS) matching. The primary endpoint was overall survival (OS). Among 2,482 MDS patients, 153 patients were assigned each to the Flu/Bu4 and Bu4/Cy groups. The 3-year OS rates were 52.7% (95% confidence interval [CI], 43.8–60.8%) and 49.5% (95% CI, 40.8–57.6%) in the Flu/Bu4 and Bu4/Cy group, respectively (P = 0.548). The 3-year progression-free survival (P = 0.858), the cumulative incidence of relapse (P = 0.536), and cumulative incidence of non-relapse mortality (P = 0.684) were not significantly different between the two groups. According to the findings of subgroup analyses, no patient had a favorable OS when using either of the two regimens. In conclusion, although our PS-matched cohort mainly comprised older patients who had a low hematopoietic cell transplantation-comorbidity index and low-risk disease status, Flu/Bu4 could be an alternative to Bu4/Cy for MDS patients prior to allo-HSCT.

DOI： 10.1038/s41409-021-01447-y

Scopus

PubMed

Publisher：Optical Materials  

Mo co-doped Y<inf>0.8</inf>Gd<inf>2.2</inf>(Al<inf>5-x</inf>Ga<inf>x</inf>)O<inf>12</inf>:Ce (x = 2.6 and 3) multicomponent garnet crystals were grown by the micro-pulling down method and the luminescence and scintillation properties were investigated. The temperature dependences of radioluminescence yield and photoluminescence decay time were measured to investigate the temperature stability of these crystals. Under excitation with 662 keV γ rays at room temperature, Y<inf>0.8</inf>Gd<inf>2.2</inf>(Al<inf>2.4</inf>Ga<inf>2.6</inf>)O<inf>12</inf>:Ce,Mo shows a higher light yield of 53,800 ph/MeV whereas Y<inf>0.8</inf>Gd<inf>2.2</inf>(Al<inf>2</inf>Ga<inf>3</inf>)O<inf>12</inf>:Ce,Mo shows a faster scintillation decay times of 50 ns (56%) + 275 ns (44%). A decrease of radioluminescence yield at low temperature observed in correlation with an appearance of the large thermoluminescence peaks can be attributed to the localization of charge carriers at shallow traps.

DOI： 10.1016/j.optmat.2021.111783

Scopus

Language：English   Publisher：Scientific Reports  

The internal exposure of workers who inhale plutonium dioxide particles in nuclear facilities is a crucial matter for human protection from radiation. To determine the activity median aerodynamic diameter values at the working sites of nuclear facilities in real time, we developed a high-resolution alpha imager using a ZnS(Ag) scintillator sheet, an optical microscope, and an electron-multiplying charge-coupled device camera. Then, we designed and applied a setup to measure a plutonium dioxide particle and identify the locations of the individual alpha particles in real time. Employing a Gaussian fitting, we evaluated the average spatial resolution of the multiple alpha particles was evaluated to be 16.2 ± 2.2 μmFWHM with a zoom range of 5 ×. Also, the spatial resolution for the plutonium dioxide particle was 302.7 ± 4.6 µmFWHM due to the distance between the plutonium dioxide particle and the ZnS(Ag) scintillator. The influence of beta particles was negligible, and alpha particles were discernible in the alpha–beta particle contamination. The equivalent volume diameter of the plutonium dioxide particle was calculated from the measured count rate. These results indicate that the developed alpha imager is effective in the plutonium dioxide particle measurements at the working sites of nuclear facilities for internal exposure dose evaluation.

DOI： 10.1038/s41598-021-84515-z

Open Access

Scopus

PubMed

Language：Japanese   Publisher：The Japanese Society of Medical Imaging Technology  

<p>Electron-Tracking Compton Camera is one of the gamma-ray imaging devices, and the gamma-ray direction and energy can be determined event by even with this camera. I show the camera structure, short history of the camera, improvement of each part and medical application.</p>

DOI： 10.11409/mit.39.217

CiNii Research

Publisher：Journal of Crystal Growth  

Homeland security is an emerging application field for inorganic scintillators. Detection and identification of radioactive materials in both individual and cargo transport requires scintillators with excellent energy resolution and high light output. On the other hand, the time characteristics of the scintillation are less crucial. Furthermore, price is a key parameter due to the large volume of the detectors. State-of-the-art halide scintillators e. g. SrI<inf>2</inf>:Eu or LaBr<inf>3</inf>:Ce can satisfy the requirements for light yield and energy resolution, but the production costs are very high due to complicated crystal growth and the high prices of rare earth metals. Cesium hafnium chloride (Cs<inf>2</inf>HfCl<inf>6</inf>) is a promising intrinsic scintillator with high light yield and excellent resolution. Moreover, its low hygroscopicity and cubic crystal structure could allow lower production costs compared to SrI<inf>2</inf> or LaBr<inf>3</inf>. Intrinsic luminescence of Cs<inf>2</inf>HfCl<inf>6</inf> is commonly attributed to self-trapped excitons. However, the luminescence of Cs<inf>2</inf>HfCl<inf>6</inf> shows complex structure and temperature dependence. This might be explained by the presence of zirconium which is a common impurity in hafnium compounds. We present a study of the influence of zirconium doping on the scintillation properties of Cs<inf>2</inf>HfCl<inf>6</inf>. Single crystals of Cs<inf>2</inf>HfCl<inf>6</inf> with zirconium doping from 0 to 1 mol% were grown by the vertical Bridgman method. Their phase purity, radioluminescence, scintillation decay, light yield, and afterglow were evaluated. Results show that zirconium doping can affect the scintillation properties of Cs<inf>2</inf>HfCl<inf>6</inf> even at concentrations comparable to impurity levels of zirconium in hafnium compounds.

DOI： 10.1016/j.jcrysgro.2021.126307

Scopus

Publisher：Journal of Crystal Growth  

In this study, Tl:CsI/KI/KCl eutectic scintillators were grown using the Bridgman–Stockbarger method by unidirectional solidification. The eutectic phases were uniformly distributed in the transverse direction and were slightly aligned along the growth direction. The Tl:CsI scintillator phase was grown as a matrix, which was then used for creating optical waveguides of the scintillation light. The expected Tl⁺ emission peak was observed at 486 nm under X-ray excitation and cathodoluminescence; this was attributed to the self-trapped exciton perturbed by TI⁺ in Tl:CsI. The decay time of the Tl:CsI/KI/KCl eutectic was 313 ns, and its light output was estimated to be 22,000 photons/MeV.

DOI： 10.1016/j.jcrysgro.2021.126287

Scopus

Language：English   Publisher：Transplantation and Cellular Therapy  

In allogeneic hematopoietic cell transplantation (allo-HCT), investigator-based clinical variables have been used for pretransplantation prognostic prediction, risk adjustment, and post-transplantation long-term screenings. Although several studies have investigated the prognostic significance of pretransplantation patient-reported outcomes (PROs) and longitudinal trends in PROs after allo-HCT, few have assessed these outcomes using the Medical Outcomes Study 12-Item Short-Form Health Survey (SF-12) and EuroQol 5 Dimension (EQ-5D) index. The present study used 18 items from the SF-12 and EQ-5D index to evaluate the prognostic impact of pretransplantation quality of life (QOL) on allo-HCT outcomes and longitudinal changes in QOL in allo-HCT recipients. This single-center prospective study included consecutive patients who underwent allo-HCT at our center between October 2014 and September 2016. All participants were followed up until October 2017. The SF-12 and EQ-5D index were administered to assess patient-reported QOL before allo-HCT and at 3 months, 6 months, 1 year, and 2 years after allo-HCT when participants visited the long-term follow-up clinic. Longitudinal trends in the QOL-adjusted means were estimated using linear mixed-effects, adjusting for pretransplantation covariates and reasons for missing QOL data. Among 157 patients who underwent allo-HCT, 145 (92%) were registered in this study, and 143 with available QOL data were analyzed. The median pretransplantation scores were 45.3 for the SF-12 physical component score (PCS), 55.6 for the mental component score (MCS), 38.8 for the role/social component score (RCS), 70.0 for the visual analog scale (VAS), and 49.0 for the EQ-5D index. Overall survival (OS) was significantly improved in patients with higher pretransplantation scores on the PCS, RCS, and EQ-5D index, and multivariable analyses showed that the median pretransplantation RCS was significantly associated with OS after allo-HCT (hazard ratio, 3.66; P =.003). The longitudinal trends in the SF-12 score showed that the PCS was improved at 2 years after allo-HCT and was comparable to the normative score for the general population. The MCS remained comparable to or higher than the normative score after allo-HCT. The RCS improved significantly beginning at 6 months after allo-HCT but remained lower than the normative score at 2 years. The VAS and EQ-5D index values showed a drop at 3 months after allo-HCT. Patient-reported QOL assessed by 18 questions on the SF-12 and EQ-5D predicted prognosis, and may be used as a prognosticator to determine treatment strategies, including preparative regimens. Although we experienced a certain amount of patient attrition in the longitudinal follow-up of QOL data, we demonstrated characteristic trajectories of QOL in different domains after adjusting for background covariates and reasons for the lack of QOL data.

DOI： 10.1016/j.jtct.2021.07.026

Scopus

PubMed

Publisher：Optical Materials  

Luminescence and scintillation characteristics of Mg²⁺-codoped (Lu<inf>x</inf>Gd<inf>3-x</inf>)Al<inf>2.4</inf>Ga<inf>2.6</inf>O<inf>12</inf>:Ce (x = 0.2–0.8) garnet crystals grown by the micro-pulling down method are investigated. The Ce³⁺ 5d<inf>1</inf> → 4f luminescence is blue-shifted with increasing Lu content due to the decrease in crystal field splitting of the 5 d levels. With increasing Lu content, the shortening of scintillation decay time accompanied with a decrease of LY value as measured at room temperature can be explained by thermal ionization of the Ce³⁺ 5d<inf>1</inf> excited state. Co-doping with Mg²⁺ results in the shortening of scintillation decay time, the reduction of LY value and afterglow intensity. At low temperature the radioluminescence quenching is observed in correlation with large thermoluminescence peaks, which can be attributed to the localization of electrons at intrinsic shallow traps.

DOI： 10.1016/j.optmat.2021.111595

Scopus

Publisher：Journal of Crystal Growth  

We have grown Ce-doped (La,Y)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> single crystal by micro-pulling-down method and investigated its optical and scintillation properties. We have successfully prepared the single crystal with (Ce<inf>0.015</inf>La<inf>0.600</inf>Y<inf>0.385</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> composition. The observed thermal quenching process could be characterized by the quenching temperature (T<inf>50%</inf>) of 526 K and its activation energy was determined to be 0.62 eV. Further considering the thermal quenching factors, it was found that the thermal quenching was caused by at least the thermal ionization and maybe also by classical thermal quenching. The light output and scintillation decay time were evaluated to be ~12,000 photons/MeV and ~42 ns, respectively. These results indicate that (Ce<inf>0.015</inf>La<inf>0.600</inf>Y<inf>0.385</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> has a great potential for application in scintillation materials.

DOI： 10.1016/j.jcrysgro.2021.126252

Scopus

Publisher：Radiation Physics and Chemistry  

The luminescence and scintillation characteristics of Ce³⁺ - doped Gd<inf>3</inf>Sc<inf>2</inf>(Al<inf>3-x</inf>Ga<inf>x</inf>)O<inf>12</inf> (x = 1, 2, 3) garnet crystals were investigated. The Ce³⁺ luminescence was blue-shifted with increasing Ga content due to the decrease of the crystal field strength. A decrease of Ce³⁺ luminescence intensity and luminescence decay time at high temperature was observed for all samples due to thermal ionization of the Ce³⁺ 5d<inf>1</inf> excited levels. With increasing Ga content the decrease of thermal activation energies, determined from temperature dependence of decay times, was obtained. Both Gd<inf>3</inf>Sc<inf>2</inf>Al<inf>2</inf>GaO<inf>12</inf>:Ce and Gd<inf>3</inf>Sc<inf>2</inf>AlGa<inf>2</inf>O<inf>12</inf>:Ce samples exhibited a comparable light yield (LY) value of 24,000 photons/MeV while the latter sample showed faster scintillation decay time of 12 ns (11%) + 56 ns (89%) with respect to those of 55 ns (28%) + 105 ns (72%) for the former sample. An acceleration of scintillation decay time with an expense of LY value was also obtained for the Mg²⁺-codoped sample. At low temperature a decrease of scintillation yield was observed in correlation with the intense thermoluminescence peaks, attributing to the localization of electrons at intrinsic shallow traps.

DOI： 10.1016/j.radphyschem.2021.109559

Scopus

Publisher：Journal of Instrumentation  

GAGG(Ce) is a novel scintillator with a fast response and high light output without a hygroscopic nature. It is expected to be a useful detector for charged particles at high-counting rates. However, the response of the GAGG(Ce) scintillator to charged particles has not been fully examined. In the present work, the light output and energy resolution of the GAGG(Ce) scintillator were measured for protons and alpha particles at E p=5-68 MeV and E α=8-54 MeV as well as gamma rays at E γ=662 keV from a 137Cs source. The results were compared with those of the CsI(Tl) scintillator. The scintillation efficiencies dL/dE of the GAGG(Ce) and CsI(Tl) scintillators were obtained and parametrized as a function of linear energy transfer dE/dx.

DOI： 10.1088/1748-0221/16/10/P10012

Scopus

Language：English   Publisher：Blood Cancer Journal  

The present study evaluated outcomes and prognostic factors in adult patients with acute myeloid leukemia (AML) after syngeneic hematopoietic stem cell transplantation (HSCT). Among patients in first complete remission (CR1), outcomes of syngeneic HSCT (Syn) were compared with those of autologous HSCT (Auto), allogeneic HSCT from human leukocyte antigen (HLA)-matched sibling donor (MSD), or allogeneic HSCT from HLA-matched unrelated donor (MUD). Among 11,866 patients receiving first HSCT, 26 in the Syn group were analyzed. The 5-year overall survival (OS) rate, the cumulative incidence of relapse, and the cumulative incidence of non-relapse mortality (NRM) were 47.8%, 59.6%, and 4.6%, respectively. The OS was significantly better in patients in CR1 (n = 13) than in patients in non-CR1 (P = 0.012). Furthermore, 39 patients in CR1 each were assigned to the Auto, MSD, and MUD groups using propensity score matching. The 5-year OS in the Syn (68.4%) was not significantly different from those in the Auto (55.9%, P = 0.265), MSD (62.4%, P = 0.419), or MUD (63.7%, P = 0.409) groups. A higher relapse in the Syn than in the MSD and MUD groups was offset by lower NRM. In summary, syngeneic HSCT might be an alternative option for AML patients in CR1.

DOI： 10.1038/s41408-021-00553-w

Open Access

Scopus

PubMed

Publisher：Journal of Luminescence  

This research dealt with the investigation of luminescence properties of undoped and La doped Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> single crystals using synchrotron radiation excitation. The influence of La³⁺ doping on the exciton emission and decay kinetics properties of Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> single crystals was studied at 7 K and room temperature. Undoped and La³⁺ doped samples showed bright luminescence in the UV spectral range. In undoped Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> crystal, the UV luminescence was associated with Lu<inf>Al</inf> antisite defects, which acted as luminescence centers in the band peaked at 295 nm La³⁺ doping in Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> crystals caused the formation of La<inf>Lu</inf> luminescence centers and increased the concentration of Lu<inf>Al</inf> antisite defects. Therefore, the luminescence of La doped Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> crystals was a superposition of the emission coming from both La<inf>Lu</inf> and Lu<inf>Al</inf> centers. Furthermore, La³⁺ doping significantly enhanced the intensity and shifted the UV luminescence of Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> crystals towards higher energy due to the dominant contribution of La<inf>Lu</inf> luminescent centers in the band peaked at 275 nm. The decay time of heavily La³⁺ doped LuAG crystals was also significantly accelerated due to the prevailing luminescence of La<inf>Lu</inf> centers.

DOI： 10.1016/j.jlumin.2021.118013

Scopus

Publisher：Japanese Journal of Applied Physics  

Optimum measurement condition of the V(x) method proposed as a fast scanning technique of the line-focus-beam ultrasonic material characterization system was theoretically investigated to realize more accurate measurement. Through numerical calculation, it was clarified that the appropriate defocus position z m with higher sensitivity used in the V(x) measurement depended on the waveform attenuation of V(z) curves. It was also clarified that the measurement error caused by the focal distance change due to temperature change in the water coupler could be reduced by choosing the lower defocus position as z m. A method for measuring the surface profile of the specimen by applying the V(x) method with z m > 0 was proposed in order to correct measurement error due to warpage of specimen surface.

DOI： 10.35848/1347-4065/ac06dc

Scopus

Publisher：Japanese Journal of Applied Physics  

Wafers of Tb-doped GdAlO<inf>3</inf>/α-Al<inf>2</inf>O<inf>3</inf> eutectic were fabricated by the micro-pulling-down method using an Ir crucible with a 25 × 25 mm² die. A prototype X-ray phase imaging detector was developed using a CMOS sensor with a fiber optic plate and the eutectic wafer. X-ray spots with an 8.24 μm period were observed using the detector. X-ray phase imaging of a nylon ball with a diameter of 4 mm was also carried out. It was observed that a phase change of approximately 2 μm occurs at the air-nylon interface. This technique of X-ray phase imaging can be realized in the absence of an absorption grating.

DOI： 10.35848/1347-4065/abd708

Scopus

Language：English   Publisher：International Journal of Hematology  

We reviewed blood product use in 729 consecutive allogeneic hematopoietic cell transplantation (allo-HCT) recipients at our center to assess the volume of red blood cells (RBCs) and platelets required after allo-HCT. The median number of bags required by day 30 was 4 for RBCs (range 0–22) and 9.5 for platelets (0–53). Multivariate analysis showed that related peripheral blood stem cell transplantation (PBSCT) required a significantly lower RBC transfusion volume by day 30 compared to unrelated bone marrow transplantation (UBMT). PBSCT from haplo-identical related donors and cord blood transplantation (CBT) required a significantly greater RBC transfusion volume. For platelet transfusion, related and unrelated PBSCT required a significantly lower volume than UBMT, and CBT a greater volume. Other factors independently associated with greater RBC transfusion volume were male sex, disease status other than complete remission, and major ABO mismatch. For platelet transfusion, these were male sex, disease status, and HCT-specific comorbidity index of 1. Although the burden of blood transfusions may not be the most important factor when choosing a donor type, our findings may provide a foundation for nationwide strategies to prepare blood products and inform aspects of national healthcare expenditures.

DOI： 10.1007/s12185-020-03041-2

Scopus

PubMed

Language：Japanese   Publisher：The Japan Society of Vacuum and Surface Science  

<p>We have developed <i>spatiotemporal</i> measurement and analysis techniques in x-ray photoelectron spectroscopy. To begin with, time-division depth profiles of gate stacked film interfaces have been achieved by NAP-HARPES (<u>N</u>ear <u>A</u>mbient <u>P</u>ressure <u>H</u>ard x-ray <u>A</u>ngle-<u>R</u>esolved <u>P</u>hoto<u>E</u>mission <u>S</u>pectroscopy) data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division ARPES data, which enables us to realize 4D-XPS analysis. It is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling in NAP-HARPES data is effective to perform dynamic measurement of depth profiles with high precision.</p>

DOI： 10.1380/vss.64.86

Open Access

CiNii Research

Publisher：Materials Science and Engineering B  

This work presents the results of creation of novel composite scintillators based on the Gd<inf>3</inf>Al<inf>5-x</inf> Ga<inf>x</inf>O<inf>12</inf>:Ce (x = 1.16–2.67) single crystalline films (SCF), grown by the LPE method onto Gd<inf>3</inf>Al<inf>2.5</inf> Ga<inf>2.5</inf>O<inf>12</inf>:Ce single crystal (SC) substrates. The scintillation properties of film/crystal epitaxial structures were investigated under α–particle and γ–quantum excitations. Under α–particle excitation, the light yield of mentioned SCF scintillators is significantly less than that in their substrates due to the influence of Pb²⁺ flux contamination and formation of Pb²⁺-Ce⁴⁺ centers. Meanwhile, these SCF scintillators under α–excitation possess significantly faster decay kinetics than that of their substrates under γ–excitation. Therefore, the Gd<inf>3</inf>Al<inf>5-x</inf>Ga<inf>x</inf>O<inf>12</inf>:Ce SCFs (x = 1.16–2.67) /Gd<inf>3</inf>Al<inf>2.5</inf>Ga<inf>2.5</inf>O<inf>12</inf>:Ce SC epitaxial structures can be used as composite scintillators for simultaneous registration of the components of mixed ionizing fluxes, specifically for detection of α–particles (SCF) and γ–quanta (substrate). The separation of the response from the SCF and substrate parts of composite scintillators under α–particle (²⁴¹Am) and γ–quantum (¹³⁷Cs) excitations occurs at large t<inf>γ</inf>/t<inf>α</inf> = 1.7–4.2 ratio.

DOI： 10.1016/j.mseb.2020.114909

Scopus

Publisher：Crystal Growth and Design  

We propose a novel crystal growth method, "Core Heating (CH) Method", which is suitable for a search of novel materials with extremely high melting points above the melting (softening) point of an Ir crucible. As a feasibility test of the novel CH method, we fabricated the conventional material, (Y0.99Ce0.01)3Al5O12 (Ce:YAG), with a melting point of ∼1970 °C, because this material can be grown by the conventional melt growth technique like the micropulling down (μ-PD) method for the comparison. We compared scintillation properties for Ce:YAG prepared by the CH and μ-PD methods in order to find if the CH method can be applied to the material search. The crystals grown by both methods showed the YAG single-phase, and almost all their optical and scintillation properties of them were comparable for both samples. Particularly, the light output of Ce:YAG crystal grown by the CH method (20,000 ± 1,000 photons/MeV) was similar to that of the sample grown by the μ-PD method (23,000 ± 1,000 photons/MeV). Therefore, we concluded that the CH method is a useful technique for the search of scintillation materials with extremely high melting points.

DOI： 10.1021/acs.cgd.0c01396

Scopus

Language：English   Publisher：Leukemia and Lymphoma  

We compared the transplant outcomes of adult patients with B-cell acute lymphoblastic leukemia characterized by high hyperdiploidy (HeH; 51–65 chromosomes) (n = 29) and those with a normal karyotype (n = 87) by propensity score-matched analysis. There were no significant differences among groups in 3-year probabilities of overall survival (OS, 63.5% vs. 55.3%, p =.553), cumulative relapse incidence (28.6% vs. 28.7%, p =.982), and non-relapse mortality (10.9% vs. 21.4%, p =.303). Three-year OS was significantly worse in HeH patients with third or later complete remission (CR) or non-CR compared with those in first CR (19.0% vs. 69.9%, p =.010). Frequently gained chromosomes +21 (75.9%), +4 (69.0%), +6 (69.0%), +10 (69.0%), and +1 (69.0%) had no significant prognostic impact on the OS of patients with HeH in multivariate analyses. Patients with HeH who may benefit from allogeneic hematopoietic stem cell transplantation should be further analyzed.

DOI： 10.1080/10428194.2021.1924374

Scopus

PubMed

Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.76.1.0_2385

Open Access

CiNii Research

Language：Japanese   Publisher：The Japanese Association for Crystal Growth  

<p>  The Burton-Cabrera-Frank (BCF) theory has been applied to metalorganic vapor-phase epitaxy (MOVPE) of N-polar (000<span style="text-decoration: overline;">1</span>) GaN. Owing to the hydrogen-rich atmosphere during MOVPE, surface N atoms of the N-polar (000-1) surface are mostly covered with H atoms. Extremely small coverage of the Ga adatoms competing with the H adatoms on the terraces can be calculated using the Langmuir adsorption isotherm. The equilibrium coverage of the Ga adatoms at steps and the equilibrium pressure of the NH₃ gas at step kinks can be calculated from the conditions of Gibbs energy balance between the sources (Ga adatom and NH₃ gas molecule) and the products (GaN and 3/2 H₂ gas molecules) and of speed balance between Ga and N incorporation into the step kinks. Growth rates of GaN on vicinal surfaces and hexagonal spiral pyramids has been calculated as a function of the trimethylgallium flow rate and compared with experimental results.</p>

DOI： 10.19009/jjacg.48-1-03

CiNii Research

Language：Japanese   Publisher：The Japanese Association for Crystal Growth  

<p>  This article presents the development of the tube shape-controlled oxide scintillator directly grown from a melt via the micro-pulling-down method. We grew tube shape-controlled Ce doped Y₃Al₅O₁₂ (tube-Ce:YAG) single-crystal scintillators with shape control using the µ-PD method, which we have reported in previous paper. We also developed and evaluated the diced Eu:SrI₂ scintillator arrays and their scintillation properties for radiation imaging application. Using a novel dicing technique specific to halide scintillation crystals, a high-energy resolution scintillator array is developed that is cost-effective and widely applicable. Finally, these techniques and development were applied for the novel imaging method we proposed, called scintillation active collimator (SAC). These results demonstrated that the SAC could be promising imaging method for the future medical imaging application.</p>

DOI： 10.19009/jjacg.48-1-05

CiNii Research

Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.76.1.0_128

Open Access

CiNii Research

Language：English   Publisher：Inflammation and Regeneration  

Hematopoietic stem cells (HSCs) have self-renewal capacity and differentiation potential into all lineages of blood cells throughout the lifetime of an organism. The function of HSCs gradually changes during aging. To date, various stress factors influencing HSC aging have been identified. The increased production of reactive oxygen species and DNA damage responses are causatively attributed to HSC aging. The increased apolarity is a prominent feature of aged HSCs, whereas it is less obvious in young HSCs. The bone marrow (BM) microenvironment niche is a crucial factor for HSC aging. Mesenchymal stem cells show skewed differentiation during aging, which leads to decreased bone formation and increased adipogenesis. The accumulation of adipocytes confers negative effects on hematopoiesis. Loss of sympathetic nerve fibers or adrenoreceptor β3 signaling induces premature HSC and niche aging. Epigenetic regulators such as polycomb group proteins and the sirtuin family of proteins act to prevent premature aging. Targeting these factors, several rejuvenation strategies for aged HSCs have been employed in mice. However, we still do not know whether these strategies can be extrapolated to human HSCs. Aging is frequently accompanied by the development of clonal hematopoiesis, which is called age-related clonal hematopoiesis (ARCH) or clonal hematopoiesis of indeterminate potential (CHIP). Most ARCH/CHIP mutations occur in genes encoding epigenetic regulators including DNMT3A, TET2, and ASXL1, which suggests the relevance of epigenetic drift during the aging process. ARCH/CHIP is a strong risk factor for subsequent hematologic cancer. Notably, it also has an impact on the development of non-malignant disorders such as coronary heart disease. Further studies are warranted to decipher the complete picture of molecular crosstalk that regulates HSC aging.

DOI： 10.1186/s41232-020-00138-3

Open Access

Scopus

PubMed

Publisher：Applied Physics Express  

Tube shape-controlled Ce-doped Y3Al5O12 (tube-Ce:YAG) single-crystal scintillators were directly grown from a melt via the micro-pulling-down method using a specially-designed iridium crucible. Back-scattering Laue images and X-ray diffraction measurements revealed the tube-Ce:YAG was a single crystal with the YAG phase. Ce distribution in the tangential direction of the tube-Ce:YAG specimen showed that Ce concentrations around the capillary positions were lower than at the corners. This was caused by the small Ce segregation coefficient in the YAG single crystal and from the small convection in the meniscus. The scintillation properties of tube-Ce:YAG specimens were comparable with previously reported Ce:YAG single crystals.

DOI： 10.35848/1882-0786/abc8ab

Scopus

Language：English   Publisher：Clinical Obesity  

Bariatric surgery is associated with a high remission rate of type 2 diabetes mellitus. However, it is unclear whether patients showing remission of diabetes actually have normal blood glucose levels throughout the day. We therefore performed continuous glucose monitoring (CGM) in 15 ambulatory patients showing remission of diabetes after laparoscopic sleeve gastrectomy (LSG) without or with duodenojejunal bypass (DJB) at the time of diabetic remission (12.9 ± 1.8 months after bariatric surgery). The definition of remission of diabetes was based on the American Diabetes Association criteria. The mean, SD, and coefficient of variation (CV) of glucose calculated from CGM were 6.2 ± 0.6 mmol/L, 1.5 ± 0.4 mmol/L, and 23.7 ± 6.2%, respectively. These values were higher than those of healthy participants without diabetes previously reported. The percentages of time spent above 10.0 mmol/L and below 3.9 mmol/L were 2.6 (IQR 0-5.0)% and 0 (IQR 0-8.0)%, respectively. Thus, patients with remission of diabetes after LSG or LSG/DJB still had substantial periods of hyperglycemia and hypoglycemia throughout the day. Therefore, we must manage patients with diabetes carefully, even after apparent remission of type 2 diabetes in response to bariatric surgery.

DOI： 10.1111/cob.12409

Scopus

PubMed

Language：English   Publisher：Health and Place  

Few studies examine associations between objectively-calculated neighbourhood built environment attributes and objectively-assessed sedentary behaviour in different geographical locations, especially in highly-populated environments. Additionally, no study, to our knowledge, has investigated associations between objective measures of neighbourhood built environment attributes and objectively-assessed sedentary behaviours in middle-aged adults, despite the fact that this is a critical stage of life when age-related functional decline begins. We examined the associations between neighbourhood built environment attributes with the total, and patterns of, objectively-assessed sedentary behaviours in a densely-populated area in Asia. Data from 866 adults (ages 40 to 64) living in Japan were included. Four classifications of sedentary behaviours, including daily total sedentary time, duration and number of long (≥30 min) sedentary bouts and breaks per sedentary hour, were estimated using hip-worn accelerometers. Individual (population density, availability of destinations, number of intersections, and distance to the nearest park) and composite (walkability and Walk Score®) neighbourhood built environment indices were calculated using geographic information systems. Covariate-adjusted multilevel linear mixed effects models were used to estimate the associations between the neighbourhood built environment attributes and sedentary behaviours. Population density and availability of destinations were positively associated with sedentary behaviours; however, the number of intersections was negatively associated with sedentary behaviours. No associations were observed between the distance to the nearest park and sedentary behaviours. There were positive associations between walkability and total sedentary time, and duration and the number of long sedentary bouts. Walk Score® was positively associated with total sedentary time and the number of long sedentary bouts. These findings suggest that urban design attributes supportive of walking (except for the number of intersections) may encourage sedentary behaviour among middle-aged adults living in densely-populated environments.

DOI： 10.1016/j.healthplace.2020.102447

Open Access

Scopus

PubMed

Publisher：Optical Materials  

The scintillators with Ce luminescent centers are widely used for radiation detection. In this study, we focused on the Ce<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> pyrosilicate scintillator and evaluated its optical and scintillation properties. From the result of the temperature dependence of quantum yield of Ce<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> under excitation into the Ce³⁺ 4f-5d<inf>1</inf> transition, it was revealed that at 300°C the Ce<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> had a quantum yield of approximately 40% of that at the room. In addition, Ce<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> had a light output of 9,400 ± 800 photons/MeV and fast decay time (~34 ns) at room temperature, and therefore, it has potential for application in radiation detection.

DOI： 10.1016/j.optmat.2020.110210

Scopus

Publisher：Materials Science and Engineering B  

The growth process, crystal composition, optical and scintillation properties of Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:La (La = 0–0.45%) single crystals were investigated in detail. The thermodynamical stability of the garnet phase formation was studied in the undoped and La doped Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> single crystals. The crystals were grown from the melt using a micro-pulling down method. Detailed composition analysis reviled the complex multiphase character of the samples. Both garnet and α-Al<inf>2</inf>O<inf>3</inf> phases were detected in the undoped and slightly La-doped samples, while heavily La-doped crystals contained the mixture of α-Al<inf>2</inf>O<inf>3</inf>, garnet and perovskites phases. The substitution La for Lu led to the formation of La<inf>Lu</inf> centers and increased the concentration of Lu<inf>Al</inf> antisite defects. Both types of centers caused a strong luminescence in the deep UV spectral range. Heavy La-doping significantly enhanced the scintillation performance of Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> crystals.

DOI： 10.1016/j.mseb.2020.114677

Web of Science

Scopus

Publisher：Physica Status Solidi Rapid Research Letters  

This research deals with a novel approach for the self-flux growth of Tb<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce single crystal using the micro-pulling-down method. The self-flux method enables the fabrication of the crystals with excellent photoconversion and scintillation properties. Tb<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce (TbAG:Ce) efficiently converts the blue light-emitting diode (LED) radiation into bright white light. The gradual change of crystal thicknesses (0.2–1 mm) allows for tuning white light temperature from cold to neutral white. The scintillation response is comparable with that of a high-quality single crystalline film counterpart with a light yield value of around 4500 photons MeV⁻¹ under α particle excitation from 239 Pu radioisotope. This is the highest value obtained for the TbAG:Ce crystal yet.

DOI： 10.1002/pssr.202000327

Web of Science

Scopus

Language：English   Publisher：European Journal of Cancer Care  

Objective: The aim of this qualitative study was to explore allogeneic haematopoietic stem cell transplantation (allo-HSCT) survivors' perspectives of stresses and their coping strategies, in order to attain a deeper understanding of their experience. Methods: We conducted semi-structured interviews with 20 Japanese allo-HSCT survivors about the stresses they experienced and how they coped. We then conducted a content-driven thematic analysis of the interview results. The interview questions probed stresses and coping strategies related to allo-HSCT. Results: We identified 74 stresses across 7 domains: symptoms after transplantation, limitations in daily life, appearance changes, relationship anxieties, work impairment and financial issues, uncertainty and disappointed expectations. In addition, 21 coping strategies were identified across 3 domains: direct efforts to manage problems, adaptive attitude, and seeking and using social support. Conclusion: By identifying a broad range of stressors associated with allo-HSCT, insight was gained as to the impact of allo-HSCT on survivors' lives. These results provide a foundation for the future development of resources for survivors, their significant others and clinicians. Stressors and coping strategies among allo-HSCT survivors were comprehensively characterised, which will provide useful information for patients and enable healthcare practitioners to provide better care.

DOI： 10.1111/ecc.13307

Web of Science

Scopus

PubMed

Language：English   Publisher：Scientific Reports  

Evidence suggests a positive effect of dog ownership on physical activity. However, most previous studies used self-reported physical activity measures. Additionally, it is unknown whether owning a dog is associated with adults’ sedentary behaviour, an emerging health risk factor. In this study, physical activity and sedentary behaviour were objectively collected between 2013 and 2015 from 693 residents (aged 40–64 years) living in Japan using accelerometer devices. Multivariable linear regression models were used, adjusted for several covariates. The means of total sedentary time and the number of long (≥ 30 min) sedentary bouts were 26.29 min/day (95% CI − 47.85, − 4.72) and 0.41 times/day (95% CI − 0.72, − 0.10) lower for those who owned a dog compared to those not owning a dog, respectively. Compared with non-owners, dog-owners had significantly higher means of the number of sedentary breaks (95% CI 0.14, 1.22), and light-intensity physical activity (95% CI 1.31, 37.51). No significant differences in duration of long (≥ 30 min) sedentary bouts, moderate, vigorous, and moderate-to-vigorous-intensity physical activity were observed between dog-owners and non-owners. A novel finding of this study is that owning a dog was associated with several types of adults’ sedentary behaviours but not medium-to-high-intensity physical activities. These findings provide new insights for dog-based behavioural health interventions on the benefits of dog ownership for reducing sedentary behaviour.

DOI： 10.1038/s41598-020-74365-6

Open Access

Web of Science

Scopus

PubMed

Publisher：IEEE Transactions on Nuclear Science  

The scintillation characteristics of Lu0.8Gd2.2 (Al5-xGax)O12:Ce,Mg ( $x = 2.6$ and 3) single crystals grown by the micropulling down method are investigated. The light yield of 27600 photons/MeV obtained for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg is higher than that of 25 400 photons/MeV obtained for Lu0.8Gd2.2Al2.4Ga2.6O12:Ce,Mg. The photoluminescence and scintillation decays measured at room temperature (RT) for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg are faster than those for Lu0.8Gd2.2Al2.4Ga2.6O12:Ce,Mg. Temperature dependence of radioluminescence (RL) intensity indicates a lower quenching temperature for Lu0.8Gd2.2Al2Ga3O12:Ce,Mg. Coincidence time resolution of a Lu0.8Gd2.2Al2Ga3O12:Ce,Mg detector in coincidence experiment with a BaF2 detector was measured to be 410 ps. The afterglow and thermally stimulated luminescence (TSL) characteristics below RT are also measured.

DOI： 10.1109/TNS.2020.3005410

Scopus

Publisher：IEEE International Ultrasonics Symposium Ius  

The factor dictating the temperature characteristic of the double layered thickness-shear resonator was investigated by evaluating the resonators with different thickness ratios. Using Ca3TaGa3Si2O14[CTGS], one of the Langasite-type piezoelectric single crystal, double layered resonators with thickness ratios x = 0.25 and 0.5 were fabricated and the temperature dependence of their resonance frequency were measured at -30 to 80°C. As a result, the temperature characteristics for the resonator with x = 0.25 exhibited different profiles depending on the order of resonance mode, on the other hand, those for the resonator with x = 0.5 exhibited no difference among all of the order. Comparing these results with the wave propagation model in the resonator, it was found that the thickness ratio of two layers at the region effectively contributing to the electric field output was deeply related to the deviation of the temperature characteristics.

DOI： 10.1109/IUS46767.2020.9251706

Scopus

Publisher：IEEE International Ultrasonics Symposium Ius  

A new method for measuring material homogeneity using fast scanning technique was proposed and demonstrated with the line-focus-beam ultrasonic-material-characterization (LFB-UMC) system. Similar velocity profiles of leaky surface acoustic wave (LSAW) for a Ca3Ta(Ga0.75Al0.25)3Si2O14[CTGAS] single crystal specimen were successfully obtained by both of the new V(x) and the conventional V(z) methods. We have verified the new V(x) method was 56 times faster than the conventional V(z) method. Although the V(z) method is superior to the V(x) method in a viewpoint of measurement accuracy, the V(x) method has great advantage enabling us to quickly evaluate material homogeneity over the wide area of specimen.

DOI： 10.1109/IUS46767.2020.9251779

Scopus

Language：English   Publisher：Biology of Blood and Marrow Transplantation  

To date, there are no data focusing on outcomes of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelodysplastic/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U). This study aimed to evaluate outcomes and prognostic factors in patients with MDS/MPN-U after allo-HSCT using Japanese nationwide registry data. The primary endpoint was 3-year overall survival (OS); secondary endpoints included the cumulative incidence of relapse and nonrelapse mortality (NRM). We evaluated the prognostic factors for 3-year OS by univariate analysis using the log-rank test. In our cohort of 86 patients with MDS/MPN-U, we found a 3-year OS of 48.5%, cumulative incidence of relapse of 23.7%, and NRM of 26.3%. The 3-year OS was significantly worse in patients age ≥50 years compared with those age <50 years (38.1% versus 65.0%; P = .049) and in patients with disease progression compared with those without disease progression (28.4% versus 57.2%; P = .042). Our results suggest that allo-HSCT may offer a curative option for patients with MDS/MPN-U, and that age and disease status could be important indicators in helping clinicians determine treatment options for these patients.

DOI： 10.1016/j.bbmt.2020.05.013

Open Access

Web of Science

Scopus

PubMed

Publisher：Physica Status Solidi B Basic Research  

Eu-doped CaF<inf>2</inf> is studied for use as a scintillator. Herein, the 3D spatial distribution of Eu ions doped in CaF<inf>2</inf> crystal is evaluated. It is confirmed that both divalent and trivalent Eu ions are doped in CaF<inf>2</inf> crystals from the luminescence spectra of the Eu-doped CaF<inf>2</inf> crystals. Using bandpass filter, the 3D spatial distribution of divalent and trivalent Eu ions is measured, respectively. The 3D spatial distribution of divalent Eu ions with ionic radius larger than that of Ca site is nonuniform with mesh-like pattern. In contrast, the 3D spatial distribution of trivalent Eu ions with ionic radius smaller than that of Ca site is uniform. In Eu-doped CaF<inf>2</inf> crystals grown by micropulling down method, strain caused by the difference in lattice constants between CaF<inf>2</inf> and a seed crystal is confirmed.

DOI： 10.1002/pssb.201900477

Web of Science

Scopus

Publisher：Physica Status Solidi B Basic Research  

Li⁺ codoping of Gd<inf>3</inf>(Ga, Al)<inf>5</inf>O<inf>12</inf>:Ce (GGAG:Ce) single crystals induces the acceleration of scintillation decay time. However, its effect on the scintillation properties of GGAG:Ce remains poorly understood. Herein, the relationship between Ce/Li concentration and scintillation properties is investigated. GGAG crystals with a range of Ce and Li concentrations are grown by the Czochralski method and the scintillation decay and light output of GGAG:Ce, Li are measured. The results show comparable or improved performance compared with conventional scintillators. In optical absorption and photoluminescence (PL) measurements, the conversion of the stable Ce³⁺ to Ce⁴⁺ is not observed in a clear manner in GGAG:Ce samples with variable Li concentration. Instead, some defect-related absorption seems to appear. Temperature dependence of PL decay for samples with variable Ce concentration is also evaluated. A shift of the luminescence quenching temperature is observed for GGAG samples with >0.2% Ce.

DOI： 10.1002/pssb.201900504

Web of Science

Scopus

Publisher：Physica Status Solidi B Basic Research  

Herein, the most advanced oxide scintillator Ce³⁺, Mg²⁺-co-doped Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> (GAGG) garnet host, grown using the Czochralski method is reported. The charge transfer absorption band in UV, such as in other Ce³⁺, Mg²⁺-co-doped oxides, reveals the creation of stable Ce⁴⁺ oxidation state, in addition to the usual Ce³⁺ one, admitted as responsible of the scintillation mechanism improvement displayed by this garnet. Strangely, the confirmation of quantitative values of Ce⁴⁺ concentration has never been done, and the goal is mainly focused on the presence of Ce⁴⁺ and the evaluation of the Ce³⁺/Ce⁴⁺ ratio measured by X-ray absorption near edge spectroscopy (XANES) spectroscopy at the Ce L<inf>III</inf> threshold of the European Synchrotron Radiation Facility (ESRF). This result is compared with those obtained for Ce³⁺, Mg²⁺-co-doped Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (LuAG) and, also, in garnets without any Mg²⁺ ions such as Ce³⁺-doped GAGG, Ce³⁺-doped LuAG, and Ce³⁺-doped YAG. The role of Li⁺ ion in place of Mg²⁺ one is also considered in Ce³⁺, Li⁺-co-doped LuAG single crystal.

DOI： 10.1002/pssb.201900510

Web of Science

Scopus

Publisher：Optical Materials  

Single crystal of the mixed-halogen compound Cs<inf>2</inf>HfCl<inf>3</inf>Br<inf>3</inf> was grown by the vertical Bridgman method, and we investigated its crystal structure and optical properties. Single-crystal X-ray diffraction and energy dispersive X-ray spectroscopy analyses indicated the chemical composition to be Cs<inf>2</inf>Hf(Cl<inf>0.578(6)</inf>Br<inf>0.422(6)</inf>)<inf>6</inf> (= Cs<inf>2</inf>HfCl<inf>3.47(4)</inf>Br<inf>2.53(4)</inf>, approximately Cs<inf>2</inf>Hf(Cl<inf>0</inf> <inf>58</inf>Br<inf>0.42</inf>)<inf>6</inf>) where the number in the parentheses denotes the estimated standard deviation in the last digit. Cs<inf>2</inf>Hf(Cl<inf>0.58</inf>Br<inf>0.42</inf>)<inf>6</inf> was found to have a cubic Fm3‾m potassium hexachloroplatinate structure consisting of Cs⁺ cations and Hf(Cl<inf>0</inf> <inf>.</inf> <inf>58</inf>Br<inf>0.42</inf>)<inf>6</inf> ²⁻ anions. The emission peak of Cs<inf>2</inf>HfCl<inf>3</inf>Br<inf>3</inf> was red-shifted by Br substitution, and the photoluminescence decays of Cs<inf>2</inf>HfCl<inf>3</inf>Br<inf>3</inf> were accelerated when compared to those of Cs<inf>2</inf>HfCl<inf>6</inf>. Cs<inf>2</inf>HfCl<inf>3</inf>Br<inf>3</inf> had an emission peak at 450 nm under X-ray irradiation, while under UV-excitation, two photoluminescence emission peaks at 420 and 525 nm were observed. The decay profile of the 420-nm emission band had a single-exponential component with a decay time of 1.95 ± 0.01 μs under the 280-nm-excitation. On the other hand, 525-nm-emisison had two decay components of 0.28 ± 0.03 μs (11%) and 6.54 ± 0.03 μs (89%) under 305-nm-photons excitation.

DOI： 10.1016/j.optmat.2020.109942

Web of Science

Scopus

Publisher：Journal of Thermal Analysis and Calorimetry  

This paper reports on the preparation of undoped cesium hafnium chloride (Cs<inf>2</inf>HfCl<inf>6</inf>) and study of its thermal properties. The Cs<inf>2</inf>HfCl<inf>6</inf> is considered, due to its excellent scintillation properties, as a promising candidate for cost-effective radiation detectors with potential to replace traditional halide scintillators, e.g., NaI:Tl and CsI:Tl. The Cs<inf>2</inf>HfCl<inf>6</inf> material was successfully synthesized from a cesium chloride and a hafnium chloride mixed together in stoichiometric ratio. The presence of only one crystalline phase of the Cs<inf>2</inf>HfCl<inf>6</inf> in the material was confirmed by the X-ray diffraction analysis. The simultaneous non-isothermal differential scanning calorimetry and thermogravimetry (DSC–TG) of the synthesized material under nitrogen atmosphere, vacuum, and in enclosed system was performed. The Cs<inf>2</inf>HfCl<inf>6</inf> decomposition and melting of CsCl–Cs<inf>2</inf>HfCl<inf>6</inf> mixture under nitrogen and vacuum were observed. On the contrary, the DSC measurement of the cesium hafnium chloride in enclosed system showed only one endothermic peak related to the congruent melting point. Furthermore, the repeated DSC–TG measurements to investigate the materials’ stability in enclosed system were carried out as well.

DOI： 10.1007/s10973-019-09087-7

Web of Science

Scopus

Language：English   Publisher：International Journal of Hematology  

We evaluated the impact of FLT3-ITD, NPM1 mutations, and double mutant CEBPa (dmCEBPa) on overall survival (OS) after relapse in patients with cytogenetically intermediate-risk acute myeloid leukemia (AML) who were treated with chemotherapy alone in the first remission (CR1). Patients aged 16–65 years diagnosed with cytogenetically intermediate-risk AML, and who achieved CR1 were included. We retrospectively analyzed FLT3-ITD, NPM1 mutations and CEBPa using samples obtained at diagnosis, which therefore did not affect the therapeutic decisions. Among 235 patients who had achieved CR1, 152 relapsed, and 52% of them achieved second CR. The rate of achieving second CR was significantly higher (85%) in those with dmCEBPa. Patients with FLT3-ITD had significantly worse OS after relapse than those without (19% vs 41%, p = 0.002), while OS was comparable between patients with and without NPM1 mutations (37% vs 34%, p = 0.309). Patients with dmCEBPa had improved OS than those without (61% vs 32%, p = 0.006). By multivariate analysis, FLT3-ITD was independently associated with worse OS after relapse [hazard ratio (HR) 1.99, 95% CI 1.27–3.12, p = 0.003], and dmCEBPa with improved OS (HR 0.40, 95% CI 0.17–0.93, p = 0.033). Our data show that screening for these mutations at diagnosis is useful for facilitating effective therapeutic decision-making even after relapse.

DOI： 10.1007/s12185-020-02894-x

Web of Science

Scopus

PubMed

Language：English  

DOI： 10.1039/d0ob00339e

PubMed

Publisher：Japanese Journal of Applied Physics  

A novel device structure "double layered thickness-shear resonator" was proposed to improve the temperature characteristics of a bulk acoustic wave resonator. In order to design the double layered resonator, optimal combination of cut angles and thickness ratio of the substrates were determined from calculations using material constants and their temperature coefficients measured for a Ca<inf>3</inf>TaGa<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> (CTGS) single crystal. Based on the results, a double layered resonator was fabricated by directly bonding two CTGS substrates with cut angles of 122°Y and 171°Y under the thickness ratio of 0.248. As a result, the double layered resonator operated successfully at a fundamental mode of around 7.5 MHz like a normal resonator exhibiting temperature compensation effect. The mechanism of the deviation from the expected value observed in the measured temperature dependence of the frequency changes was discussed using the model of the wave propagation and the electric field generated in the double layer structure.

DOI： 10.35848/1347-4065/ab80da

Web of Science

Scopus

Publisher：Crystals  

Ce-doped LaBr<inf>3</inf> /AEBr<inf>2</inf> (AE = Mg, Ca, Sr, Ba) eutectics were grown using the Bridgman–Stockbarger (BS) method in quartz ampoules. The eutectics (AE = Mg and Ca) showed optical transparency like optical fiber bundles. A grown Ce-doped LaBr<inf>3</inf> /MgBr<inf>2</inf> eutectic shows a 355 nm emission ascribed to Ce³⁺ 4f-5d transition under X-ray excitation. The smaller the ionic size of AE, the higher the light yield of the sample was. The light yield of Ce:LaBr<inf>3</inf> /MgBr<inf>2</inf> was 34,300 photon/MeV, which is higher than Ce:LYSO standard. Scintillation decay time under 662 keV gamma-ray excitation was 18.8 ns.

DOI： 10.3390/cryst10070584

Open Access

Web of Science

Scopus

Publisher：Crystals  

A novel single-crystal growth method was developed, using arc plasma and metal melt, for a quick survey of high melting point materials. Single crystals of Yb-doped Lu<inf>2</inf>O<inf>3</inf>, Lu<inf>0.388</inf>Hf<inf>0.612</inf>O<inf>1.806</inf>, and Lu<inf>0.18</inf>Hf<inf>0.82</inf>O<inf>1.91</inf>, with melting points of 2460, 2900, and 2840^◦C, respectively, were grown by an indirect heating method using arc plasma. We refer to this indirect heating growth method as the core heating (CH) method. The CH-grown Yb1%-doped Lu<inf>2</inf>O<inf>3</inf> sample showed a full width at half maximum of 286 arcsec in the X-ray rocking curve. This value is better than the 393 arcsec obtained for the crystal grown by the micro-pulling-down (µ-PD) method. The Yb charge transfer state (CTS) emission was observed at 350 nm in the Yb1%-doped Lu<inf>2</inf>O<inf>3</inf> and Lu<inf>0.18</inf>Hf<inf>0.82</inf>O<inf>1.91</inf>. In the case of the µ-PD method, using a rhenium (Re) crucible, absorption due to Re contamination and a resulting reduction in the Yb CTS emission were confirmed. However, contamination did not influence the properties observed in the crystals grown by the CH method.

DOI： 10.3390/cryst10070619

Open Access

Web of Science

Scopus

Language：English   Publisher：Diabetes Research and Clinical Practice  

Aims: Evaluation of the retinal microcirculation is key to understanding retinal vasculopathies, such as diabetic retinopathy. Laser speckle flowgraphy (LSFG) has recently enabled us to directly evaluate the vascular resistance in both retinal vessels and capillaries, non-invasively. We therefore assessed whether retinal vessel blood flow and/or the capillary microcirculation are associated with blood flow in the cervical arteries in diabetic patients without severe retinopathy. Methods: We enrolled 110 type 2 diabetes patients, with no or mild non-proliferative diabetic retinopathy, in this prospective cross-sectional study. We measured the resistivity indices (RIs) of the retinal vessel and capillaries by LSFG and those of cervical arteries by Doppler ultrasonography, followed by analyzing associations. Results: The RIs of not only the carotid but also vertebral arteries were associated with those of retinal vessel blood flow and the retinal capillary microcirculation. Multiple regression analyses revealed these associations to be independent of other explanatory variables including age and diabetes duration. Conclusions: We obtained novel and direct evidence demonstrating a close association between the retinal microcirculation and cervical artery hemodynamics in diabetic patients. These findings suggest shared mechanisms to underlie micro- and macro-angiopathies. Thus, high vascular resistance of cervical arteries may be a risk of developing retinopathy.

DOI： 10.1016/j.diabres.2020.108240

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Scopus

PubMed

Web of Science

Publisher：Journal of Crystal Growth  

Single crystal scintillators are extensively used in various radiation detection applications and their scintillation performances can be improved via co-doping. Therefore, in this study, tungsten-ion co-doped Ce:Gd<inf>3</inf>(Ga,Al)<inf>5</inf>O<inf>12</inf> (Ce:GGAG) crystals were grown using the micro-pulling-down (μ-PD) method to investigate the effects of co-doping on their scintillation properties. The relationships between the W concentration, optical and luminescence properties, and radiation response of the W-co-doped Ce:GGAG crystals were evaluated. The W-co-doped Ce 0.5%:Gd<inf>3</inf>Ga<inf>3</inf>Al<inf>2</inf>O<inf>12</inf> single crystals of diameter 3 mm and length 30–60 mm were grown by the μ-PD method. The light yield increased at W concentrations of 200 and 500 ppm and decreased at W concentrations above 1000 ppm. There was no significant change in the fast decay component of scintillation.

DOI： 10.1016/j.jcrysgro.2020.125513

Scopus

Publisher：IEEE Transactions on Nuclear Science  

Effects of the tungsten (W) ions co-doping on the crystal growth, optical and scintillation properties for the Czochralski (Cz) grown Ce:Gd3Ga3Al2O12(GGAG) single crystals were investigated. The W 0%, 0.1%, 0.3%, 1%, and 5% co-doped Ce 1%:GGAG single crystals with a diameter of 1 in and length of 60-80 mm were grown by the Cz method. The effective segregation coefficient of the W ions was found as 0.002, 0.001, and 0.005 for W 0.1%, 0.3%, and 1%, Ce:GGAG, respectively. The segregation of W ions in GGAG host, light yield, and scintillation decay of the W co-doped Ce:GGAG were evaluated. The light yield decreased as the concentration of W co-dopant increased and toward the tail of the crystal. Furthermore, the defect role and related charge trapping in the W co-doped crystals were monitored by the thermo-stimulated luminescence.

DOI： 10.1109/TNS.2020.2968088

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Scopus

Publisher：IEEE Transactions on Nuclear Science  

Carbazole crystals were grown using self-seeding vertical Bridgman technique, and the scintillation properties for neutron detection were investigated. Results of powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses indicated the single phase of the grown carbazole crystal with orthorhombic structure. Photo-and radio-luminescence measurements were carried out, and maxima of both emission peaks were at 420 nm. The light yield under 5.5-MeV alpha-ray irradiation was estimated to be 1.87 times higher than that of lithium glass GS-20. The scintillation decay time under neutron irradiation was estimated to be 11.4 ± 0.3 ns. It follows from the temperature dependence measurements that the light output under 662-keV gamma-ray excitation decreases with increasing temperature.

DOI： 10.1109/TNS.2020.2996276

Web of Science

Scopus

Publisher：IEEE Transactions on Nuclear Science  

DOI： 10.1109/TNS.2020.2998652

Scopus

Publisher：IEEE Transactions on Nuclear Science  

This article is directed on the creation of composite scintillators which are based on the films and crystals of R2Si2O7:Ce (R = Lu, Gd, La) pyrosilicates using the liquid phase epitaxy (LPE) growth method for application in the radiation monitoring of different components of mixed ionization fluxes. Such types of composite scintillators are epitaxial structures containing film scintillators grown by the LPE method onto the substrates of crystal scintillators. In this article, the film and crystal parts of the composite scintillators were fabricated from effective scintillation materials on the base of Ce3+ doped Gd2-xLuxSi2O7 and Gd2-xLaxSi2O7, and x = {0} and 0.25 mixed pyrosilicates with various scintillation decay kinetics due to the different Lu/Gd/La cation content. We briefly report on the results of the LPE growth of the composite scintillators based on the Ce3+ doped (Lu,Gd)2Si2O7 films and (Gd,La)2Si2O7:Ce crystal substrates, as well as the results of investigation of their luminescent and scintillation properties.

DOI： 10.1109/TNS.2020.2983657

Web of Science

Scopus

Publisher：IEEE Transactions on Nuclear Science  

This article presents the development of diced SrI2:Eu arrays and their scintillation properties when coupled with a multipixel photon counter (MPPC) array. Using a dicing technique specific to halide scintillators, a high-energy resolution scintillator array is developed that is cost-effective and widely applicable. The developed SrI2:Eu arrays are of 3 × 3 × 3 mm3/pixel 4 × 4 matrix (TYPE1) and 1 × 1 × 1 mm3/pixel 9 × 9 matrix (TYPE2) structures. We fabricated test gamma-ray detector modules consisting of the TYPE1 and TYPE2 arrays coupled with an MPPC array. The mean peak to valleys ratio is 85.3 ± 14.9 for the TYPE1 array and 38.5 ± 16.6 for the TYPE2 array detector. The average energy resolutions obtained for the TYPE1 and TYPE2 gamma-ray detectors were 5.4 ± 0.4% full-width at half-maximum (FWHM) and 5.2 ± 0.6% FWHM, respectively, for 662-keV gamma-rays. The variation in the signal pulse height of the TYPE1 and TYPE2 detectors was only 10.6% and 10.4% in FWHM, respectively. These results demonstrated that the dicing technique proposed in this article could be applied to hygroscopic halide scintillators.

DOI： 10.1109/TNS.2020.2986460

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Scopus

Publisher：IEEE Transactions on Nuclear Science  

A new red-emitting halide scintillator Rb2HfI6 was developed using the vertical Bridgman furnace and quartz ampoule. Under X-ray irradiation, Rb2HfI6 had a broad emission band of around 725 nm. The light output and energy resolution were determined to be 40000 photons/MeV and 7.4% (full-width at half-maximum at 662 keV), respectively. Since red photons are transmitted with smaller losses than blue or yellow photons inside an optical fiber, a long-fiber-reading radiation detection system using the high light-output red scintillator can be established for severe or hazardous environments. We fabricated the Rb2HfI6 scintillation crystal and performed the gamma-ray detection test under high-dose irradiation condition from a 60Co source with an activity of 100 TBq. The dynamic range of the Rb2HfI6 gamma-ray detection with a 20-m optical fiber was evaluated and compared with the previously developed Cs2HfI6 crystal and the conventional deep-red Cr: α-Al2O3 (ruby) scintillator. The gamma-ray doses from 0.4 to 1 kSv/h were successfully measured using Rb2HfI6 through the 20-m fiber.

DOI： 10.1109/TNS.2020.2976695

Web of Science

Scopus

Publisher：IEEE Transactions on Nuclear Science  

The scintillation properties of Mg2+-codoped Lu0.6Gd2.4Al2Ga3O12:Ce (LGAGG:Ce,Mg) single crystal grown by Czochralski's method are investigated. The light yield (LY), scintillation decay time, and coincidence time resolution are presented in comparison with a GAGG:Ce,Mg reference crystal. The LY of 26 200 photons/MeV obtained for LGAGG:Ce,Mg is lower than that of 39 600 photons/MeV for GAGG:Ce,Mg. Despite a lower LY value, the time resolution of LGAGG:Ce,Mg is comparable to that of GAGG:Ce,Mg due to its faster scintillation decay time. LGAGG:Ce,Mg exhibits a much faster afterglow decay and a lower thermally stimulated luminescence intensity with respect to GAGG:Ce,Mg.

DOI： 10.1109/TNS.2020.2984518

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Scopus

Publisher：IEEE Transactions on Nuclear Science  

We measured the scintillation light yield of ZnWO4 crystals using a quasi-monochromatic neutron beam energy of 865 keV. Irradiating the neutron beam on two surfaces, which are almost perpendicular to the crystal axis, the light yield of oxygen recoil was measured. The obtained light yield ratio of a neutron recoil to gamma-ray-induced electron recoil for two surfaces was 0.235 ± 0.026 and 0.199 ± 0.020, respectively, which corresponds to 15.3% of anisotropy for 200-keV nuclear recoils of this crystal. This property can be applied to a direction-sensitive dark matter (DM) detector.

DOI： 10.1109/TNS.2020.2985027

Open Access

Web of Science

Scopus

Publisher：IEEE Transactions on Nuclear Science  

Scintillation characteristics of Y<inf>0.8</inf>Gd<inf>2.2</inf> (Al<inf>5-x</inf>Ga<inf>x</inf>)O<inf>12</inf>:Ce,Mg ($x = 2.6$ and 3) single crystals are presented. At 662-keV $\gamma $-rays, the light yield of 35 600 photons/MeV obtained for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mg is higher than that of 32 600 photons/MeV for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2.4</inf>Ga<inf>2</inf><inf>6</inf>O<inf>12</inf>:Ce,Mg. Scintillation decay components of 32.3 ns (52.4%) + 104 ns (47.6%) obtained for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mg are faster than those of 11.5 ns (5%) + 51.2 ns (69%) + 302 ns (26%) obtained for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2.4</inf>Ga<inf>2</inf><inf>6</inf>O<inf>12</inf>:Ce,Mg. The coincidence time resolution of 336 and 389 ps was obtained, respectively, for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mg-photomultiplier (PMT) and Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2.4</inf>Ga<inf>2</inf><inf>6</inf>O<inf>12</inf>:Ce,Mg-PMT, in coincidence experiment with a BaF<inf>2</inf>-PMT detector. The radioluminescence yield at room temperature (RT) is comparable for both crystals while the yield below 130 K is about 20% higher for Y<inf>0.8</inf>Gd<inf>2.2</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce,Mg. Afterglow and thermally stimulated luminescence (TSL) below RT are also measured.

DOI： 10.1109/TNS.2020.2975734

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Scopus

Language：English   Publisher：Biology of Blood and Marrow Transplantation  

With increasing focus on the importance of long-term survivorship care after allogeneic hematopoietic cell transplantation (allo-HCT), more institutions have been establishing long-term follow-up (LTFU) clinics. Currently, however, with varying volumes of HCT procedures and resources, there is no standardized operation of these clinics in HCT centers. We conducted a nationwide questionnaire survey to characterize the current operation of LTFU clinics in Japan. We targeted 271 HCT centers (189 adult and 82 pediatric) that registered allo-HCT cases to the national transplant registry database. The response rate was 69%, and 117 of the 188 participating centers (62%) had an established LTFU clinic. The most frequent reason cited for not operating an LTFU clinic was a “lack of human resources,” especially nurses. Most centers with an LTFU clinic targeted allo-HCT recipients, although autologous HCT survivors were followed up at 18% of adult centers and 48% of pediatric centers. Ninety-two percent of centers did not terminate LTFU at a specific time point, and 56% recommended that patients visit the LTFU clinic beyond 5 years after HCT. Fifteen of 20 pediatric centers indicated that they did not routinely refer survivors who underwent HCT at a young age to an adult HCT center for their adulthood LTFU. We found that staffing and standard practices varied widely among centers, and that most centers continued to see long-term HCT survivors at their own outpatient clinics. The development of common LTFU tools may help standardize LTFU practices and facilitate efficient transitions.

DOI： 10.1016/j.bbmt.2020.01.008

Open Access

Web of Science

Scopus

PubMed

Publisher：Acta Physica Polonica A  

Plate shaped Fe–Al alloy crystals were successfully grown using the µ-PD method. The orientation and grain size could be controlled by using the well oriented Fe0.95Al0.05 seed crystal. The as-grown Fe0.82Al0.18 and Fe0.80Al0.20 showed the magnetostriction 3/2λ = 121 and 149 ppm, respectively, which is comparable to the values for single crystal samples grown by the Bridgman-Stockbarger method. Distributions of Fe and Al were homogenous along the growth direction within standard deviations of 0.35% and 1.3%, respectively. A prototype vibration energy harvester was demonstrated using the grown Fe–Al alloys.

DOI： 10.12693/APhysPolA.137.1009

Open Access

Web of Science

Scopus

Publisher：Journal of Crystal Growth  

The phase diagram of the BaI<inf>2</inf>-LuI<inf>3</inf> system was created using powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis, and a eutectic scintillator crystal was grown by the halide-vertical bridgman (H-VB) method. The results of XRD patterns and DSC curves showed that the phase diagram of the BaI<inf>2</inf>-LuI<inf>3</inf> system had a eutectic point around 77.5 mol% BaI<inf>2</inf>/22.5 mol% LuI<inf>3</inf>, and no new compound was generated from BaI<inf>2</inf> and LuI<inf>3</inf>. The 77.5 mol% BaI<inf>2</inf>/22.5 mol% LuI<inf>3</inf> eutectic crystal was composed of BaI<inf>2</inf> in rod phase and LuI<inf>3</inf> in matrix phase. In addition, the Ce-doped 77.5 mol% BaI<inf>2</inf>/22.5 mol% LuI<inf>3</inf> specimen showed emission peaks originating from 5d–4f transition of Ce³⁺ ion in the X-ray radioluminescence (XRL) spectrum and the decay time under γ-ray irradiation was approximately 38 ns.

DOI： 10.1016/j.jcrysgro.2020.125573

Web of Science

Scopus

Publisher：Applied Physics Express  

We have developed a remote scintillation detector using a CCD spectrometer and a red-emitting scintillator coupled with a 20 m optical fiber for ultra-high-dose conditions. Gamma rays were detected with a conventional deep-red-emitting ruby scintillator and Cs<inf>2</inf>HfI<inf>6</inf>, which is a novel material with 700 nm red emission and a high light output. The scintillators were irradiated with gamma rays from a ⁶⁰Co source under an effective dose rate from ∼0.002 to ∼1 kSv h^-1. The integrated area of the Cs<inf>2</inf>HfI<inf>6</inf> emission spectra was larger than that of the ruby, and good linearity of the Cs<inf>2</inf>HfI<inf>6</inf> signal as a function of dose rate was confirmed.

DOI： 10.35848/1882-0786/ab77f7

Web of Science

Scopus

Publisher：Journal of Crystal Growth  

Edge defined Film Fed Growth (EFG) method with molybdenum (Mo) crucible and die was studied for the growth of several oxide-based single crystals. At first, reactivity between the molybdenum (Mo) metal and oxide melts of Ce:(Lu,Y)<inf>2</inf>SiO<inf>5</inf> (LYSO) Ce:Y<inf>2</inf>SiO<inf>5</inf> (YSO), Ce:Gd<inf>3</inf>(Al,Ga)<inf>5</inf>O<inf>12</inf> (GAGG), Ce:Lu<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (LuAG), Ce:Y<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (YAG) was investigated. The experimental and calculation results on the reactivity with Mo show that the aluminum garnets (LuAG, YAG) had the smallest reactivity with Mo metal. On the contrary, GAGG showed the strongest reaction with Mo. Then, the multiple-die grown shaped single crystal growth of Ce:LuAG was demonstrated by EFG method. Single crystal plates up to 320 mm in length were grown successfully. The homogeneity of dopant distribution, Mo contamination, luminescence and scintillation responses of the grown crystals were evaluated.

DOI： 10.1016/j.jcrysgro.2020.125510

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Scopus

Publisher：Journal of Crystal Growth  

Time and cost effective methods are highly desirable in research and development of new scintillators. Modern techniques like micro-pulling down (μ-PD) are suitable for material screening but are unfit for the growth of some crystals. These crystals must be grown by different methods that are usually very time demanding. Modification of halide μ-PD apparatus by custom made elements allowed us to grow cesium hafnium chloride (Cs<inf>2</inf>HfCl<inf>6</inf>) by vertical Bridgman method (VB) with significantly reduced growth time. Structural and optical properties of samples prepared from as-grown crystals were studied and compared to crystals grown by standard VB method. The X-ray diffraction confirmed the formation of cesium hafnium chloride single-phase and natural cleavage of the crystals along the (1 1 1) crystallographic plane. Photoluminescence emission, excitation, absorption, and radioluminescence spectroscopy revealed that the optical quality of the crystals grown by modified VB method was comparable to the quality of the crystals grown by standard VB method. Therefore we can use samples prepared by modified VB to estimate and optimize the performance of Cs<inf>2</inf>HfCl<inf>6</inf> based crystals in scintillation detectors. This setup allows the time and cost-effective material screening and it is a powerful tool for the development of new halide based single crystal scintillators.

DOI： 10.1016/j.jcrysgro.2020.125479

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Scopus

Language：English   Publisher：International Journal of Hematology  

Patients with aggressive adult T-cell leukemia-lymphoma (ATL) have dismal outcomes with intensive chemotherapy. Early up-front allogeneic hematopoietic stem cell transplantation (allo-HSCT) is generally recommended. However, the choice of stem cell source, i.e., unrelated bone marrow transplant (UBMT) or cord blood transplantation (CBT), when an HLA-matched related donor is unavailable remains controversial. Thus, we undertook a decision analysis to compare the outcomes of two therapeutic strategies: chemotherapy followed by up-front UBMT at 6 months, and chemotherapy followed by up-front CBT at 3 months. Patients were stratified into low-, intermediate-, and high-risk groups according to the modified ATL-prognostic index. The model simulated life expectancy (LE) and quality-adjusted LE (QALE). LE following up-front UBMT was higher than that following up-front CBT in the low-risk group (2.63 vs. 2.28 years), but was comparable in the intermediate- (2.06 vs. 2.01 years) and high-risk groups (1.25 vs. 1.30 years). The Monte Carlo simulation for LE and QALE in each risk group showed that there was significant uncertainty in all categories. In conclusion, up-front UBMT was superior to up-front CBT in the low-risk group, but the strategies were comparable in the intermediate- and high-risk groups.

DOI： 10.1007/s12185-019-02777-w

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Scopus

PubMed

Publisher：Journal of Science Advanced Materials and Devices  

Се-doped (Pb,Gd)<inf>3</inf>(Al,Ga)<inf>5</inf>O<inf>12</inf> single crystalline garnet films were grown using liquid-phase epitaxy from four series of supercooled PbO–B<inf>2</inf>O<inf>3</inf>-based melt solutions on Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf> and Gd<inf>3</inf>Al<inf>2.26</inf>Ga<inf>2.74</inf>O<inf>12</inf> single crystal substrates. The optical and scintillation properties of the epitaxial garnet films were studied. The 5d-4f emission of Ce³⁺ ions within 450–650 nm was observed. The highest pulsed cathodoluminescence yield and scintillation yield values under ¹³³Ba excitation for the Pb<inf>0.01</inf>Ce<inf>0.02</inf>Gd<inf>2.97</inf>Al<inf>3.13</inf>Ga<inf>1.87</inf>O<inf>12</inf> film were 43,100 photons/MeV and 20,000 photons/MeV, respectively. The pulsed cathodoluminescence decay times of the film were 1.8 (1%), 24 (25%), and 60 ns (74%), and the scintillation decay times were 3.9 (7%) and 43.6 ns (93%). Because of the rapid decay and high light yield, Се-doped (Pb,Gd)<inf>3</inf>(Al,Ga)<inf>5</inf>O<inf>12</inf> garnet films can be used in X-ray scintillators for different applications, such as homeland security.

DOI： 10.1016/j.jsamd.2020.01.005

Open Access

Web of Science

Scopus

Publisher：Journal of Luminescence  

Both the total luminescence yield (TLY) and the luminescence spectra of scintillators were measured to identify which scintillator exhibited high luminosity in the soft X-ray (SX) region from 300 eV to 1.3 keV. The TLY intensities and the peak intensities of the luminescence spectra were compared to identify the scintillators that have high luminosity for reducing the pixel size of a two-dimensional detector by applying the stimulated emission depletion phenomenon. The obtained TLY intensities were Tl:CsI, Eu:GGG, Ce:LYSO, Tb:LSO, Eu:YAP and Ce:YAP (in descending order of strength), which differs from the known luminosities in the hard X-ray region. The order of the measured TLY intensity and the change of order between the present and the previous values of luminosities can be explained by the number of secondary electrons generated in the base material of the scintillator in the SX region.

DOI： 10.1016/j.jlumin.2019.116850

Open Access

Web of Science

Scopus

Publisher：Crystals  

The microstructure and mechanical properties of platinum (Pt) fibers fabricated by unidirectional solidification using the alloy-micro-pulling-down (A-μ-PD) method were investigated using a Universal Testing Machine and Electron Backscattered Diffraction (EBSD). The Pt fiber fabricated at a growth rate of 10 mm/min was composed of relatively large grains with <100> crystal orientation along the growth direction. The crystal orientation was consistent with the easy axis of the crystal growth on the face-centered-cubic (f.c.c.) structure. On the other hand, the adjacent grains of the Pt fiber fabricated at 50 mm/min were randomly oriented owing to a faster growth rate. In tensile tests, the Pt fibers fabricated by the A-μ-PD method indicated extremely different stress–strain curves compared to the commercial Pt wire. The maximum tensile stress of the Pt fiber reached ~100 MPa, and the Pt fiber ruptured after 58% nominal strain.

DOI： 10.3390/cryst10030216

Open Access

Web of Science

Scopus

Publisher：Crystals  

Co-Cr-Mo alloy fibers of 2 mm in diameter were fabricated from the melt at 1, 2, and 5 mm/min growth rates by unidirectional solidification using an alloy-micro-pulling-down (A-µ-PD) method to control the microstructure. All elements, Co, Cr, and Mo, were distributed in stripes elongated along the growth direction due to constitutional undercooling. Both Co-Cr-Mo fibers fabricated at 2 and 5 mm/min growth rates were composed of the γ phase with a face-centered cubic structure (fcc-γ phase) and ε-phase with a hexagonal close-packed structure (hcp-ε phase), and the ratio of the fcc-γ phase in the fiber fabricated at 5 mm/min growth rate was higher than that in the fiber fabricated at 2 mm/min. The results suggest that a faster growth rate increases the ratio of the fcc-γ phase in the Co-Cr-Mo fiber fabricated by unidirectional solidification.

DOI： 10.3390/cryst10010011

Open Access

Web of Science

Scopus

Publisher：Japanese Journal of Applied Physics  

Tl:CsI/CsCl/NaCl eutectic scintillators were grown by the Bridgman-Stockbarger method. The eutectic phases were uniformly distributed in the transverse direction and slightly aligned along the growth direction. Then, the CsI phase can be designed as columnar. The expected emission peak observed at 550 nm was observed under X-ray excitation and cathodoluminescence and was ascribed to the self-trapped exciton perturbed by TI+ in Tl:CsI. The mapping of optically waveguided light emission was observed by confocal laser microscopy, consequently optical waveguiding of Tl+ emission in the CsI phase was demonstrated.

DOI： 10.35848/1347-4065/abcdab

Scopus

Publisher：Proceedings of SPIE the International Society for Optical Engineering  

HiZ-GUNDAM is a future satellite mission which will lead the time-domain astronomy and the multi-messenger astronomy through observations of high-energy transient phenomena. A mission concept of HiZ-GUNDAM was approved by ISAS/JAXA, and it is one of the future satellite candidates of JAXA's medium-class mission. We are in pre-phase A (before pre-project) and elaborating the mission concept, mission/system requirements for the launch in the late 2020s. The main themes of HiZ-GUNDAM mission are (1) exploration of the early universe with high-redshift gamma-ray bursts, and (2) contribution to the multi-messenger astronomy. HiZ-GUNDAM has two kinds of mission payload. The wide field X-ray monitors consist of Lobster Eye optics array and focal imaging sensor, and monitor ~1 steradian field of view in 0.5 - 4 keV energy range. The near infrared telescope has an aperture size 30 cm in diameter, and simultaneously observes four wavelength bands between 0.5 - 2.5 µm. In this paper, we introduce the mission overview of HiZ-GUNDAM.

DOI： 10.1117/12.2560603

Scopus

Publisher：Proceedings of SPIE the International Society for Optical Engineering  

MeV gamma-ray astronomy in an energy range of hundreds of keV to tens of MeV is a unique window for observing nucleosynthesis, however this field has not opened up until recently because of imaging difficulties. Thus, we are developing an electron-tracking Compton camera (ETCC), which consists of a gaseous electron tracker and pixel scintillator arrays, as a next generation MeV gamma-ray telescope. Because the ETCC detects all parameters after Compton scattering, we can determine the momentum of incident gamma-rays with powerful background rejection. This ETCC has confirmed low-noise and high-sensitivity observations at high altitude through Sub-MeV gamma-ray Imaging Loaded-on-balloon Experiment I (SMILE-I) in 2006 and SMILE-2+ in 2018. Therefore, we are planning scientific observations using an ETCC with an effective area of ∼10 cm² for 0.3 MeV, a spatial resolution of ≤10 degrees for 0.5 MeV, and a field of view of 3 sr as the next step (SMILE-3). In this paper, we present the design of the SMILE-3 ETCC and its expected observations.

DOI： 10.1117/12.2560886

Scopus

Publisher：Journal of Luminescence  

This research deals with the luminescence and physical properties of Gd<inf>3</inf>(Ga,Al)<inf>5</inf>O<inf>12</inf>:Ce single crystal set and it is a complementary study to analogous (Y,Gd)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce and (Gd,Lu)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce single crystal sets. Those three groups of materials show similar luminescence and physical properties. In this research, the influence of substitution Ga for Al in Gd<inf>3</inf>(Ga,Al)<inf>5</inf>O<inf>12</inf>:Ce single crystals on the luminescence and scintillation characteristics as well as thermodynamical stability of the garnet phase is studied, and it is compared to (Y,Gd)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce and (Gd,Lu)<inf>3</inf>Al<inf>5</inf>O<inf>12</inf>:Ce single crystal sets. The unbalanced substitution Ga for Al makes garnet phase thermodynamically unstable and leads to the formation of the multiphase system with luminescence centers in UV and visible spectral ranges. The wavelength-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, photoluminescence and decay kinetic measurements reviled all phase types within multiphase crystals. Temperature dependent measurements were applied to determine the quenching mechanism for Ce³⁺ luminescence. The timing characteristics are studied as the function of Ga content.

DOI： 10.1016/j.jlumin.2019.116724

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Scopus

DOI： 10.1182/blood-2019-127725

Web of Science

Language：English   Publisher：International Journal of Hematology  

The prognostic significance of FLT3-tyrosine kinase domain (TKD) mutations remains unknown. To investigate the prognostic impact of FLT3-TKD, 676 de novo acute myeloid leukemia (AML), we retrospectively analyzed cases and conducted a review of the literature. Of the 676 de novo AML cases, 34 (5.0%) were FLT3-TKD-positive; both FLT3-TKD and FLT3-ITD were noted in only two cases (0.3%). Although no significant differences in relapse-free survival (RFS) were noted, FLT3-TKD-positive cases showed better prognoses than FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.152). For overall survival (OS), although FLT3-TKD-positive cases showed prognoses similar to those for FLT3-WT cases, their prognoses were significantly better than those of FLT3-ITD-positive cases (FLT3-TKD versus FLT3-ITD, p = 0.032). Moreover, the 5-year OS for FLT3-TKD-positive cases was 46.1%, indicating that this as an intermediate prognosis group. Although no reports from Asia have indicated a frequency of FLT3-TKD-positive cases > 10%, several reports from Europe and the United States have indicated frequencies > 10%. This suggests the possibility that FLT3-TKD-positive cases are less common in Asia than in Europe and the United States. We anticipate that in the future, the appearance of targeting agents, such as FLT3 inhibitors, will improve the prognosis of FLT3-TKD-positive AML relative to that of FLT3-WT AML.

DOI： 10.1007/s12185-019-02720-z

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Scopus

PubMed

Web of Science

Publisher：2019 IEEE Nuclear Science Symposium and Medical Imaging Conference NSS Mic 2019  

Inorganic scintillators have been used for underground astroparticle physics experiment, such as dark matter search and double beta decay search. We have developed CaI<inf>2</inf> which has a large amount of luminescence and contains ⁴⁸Ca from double beta decay nuclei. Half-inch CaI<inf>2</inf> crystals were prepared by the Bridgman method in Institute for Materia Research, cut into several mm squares, and the scintillation characteristics were measured. The light emission amount was 107,000 ph. / MeV, 2.7 times NaI (Tl) and 10 times undoped CaF<inf>2</inf>. The light emission wavelength was 410 nm, which was in agreement with sensitive wavelength of photomultiplier tubes. When the waveform discrimination characteristics were measured using alpha rays of ²⁴¹Am and gamma rays of ¹³⁷Cs, it was found that there was a large difference in the first 300 ns between the waveforms. Our pulse shape discrimination analysis using fast/total ratio method gives 4.2 for CaI<inf>2</inf> in figure of merit, and it was 2.0 for CaF2(Eu). CaI<inf>2</inf> showed high potential for pulse shape discrimination. Low temperature dependence of light yield was also investigated, and we confirm that light yield of CaI<inf>2</inf> increase at low temperature. At present, the growth and processing of large crystals is difficult due to the strong deliquescence and cleavage of CaI<inf>2</inf>. Work is underway to develop better growth and processing method for CaI<inf>2</inf> crystal.

DOI： 10.1109/NSS/MIC42101.2019.9059845

Scopus

Publisher：Journal of Solid State Chemistry  

Al concentration dependence of the crystal structure on Ca<inf>3</inf>Ta(Ga<inf>1-x</inf>Al<inf>x</inf>)Si<inf>2</inf>O<inf>14</inf> (CTGAS) piezoelectric single crystals were investigated by X-ray crystal structure analysis. O(2)-Si-O(2) and Si-O(2)-(Ga,Al) bond angles systematically increased with increasing Al concentration, and the result suggests that the increase of structural anisotropy by the Al substitution is attributable to the planarization of the O(2)-Si-O(2)-(Ga,Al). In addition, (Ga,Al)-O(2), (Ga,Al)-O(3) and Ca-O(1) bond lengths systematically decreased with increasing the Al substitution. The cation shift of the Si and (Ga,Al) ions out of center from the barycenter of the oxygen coordination environment decreased with increasing Al concentration.

DOI： 10.1016/j.jssc.2019.06.009

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Scopus

Language：English   Publisher：Biology of Blood and Marrow Transplantation  

The aim of this study was to determine whether impaired quality of life (QOL) persisted among patients who experienced resolved chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). Eligible participants were patients who were relapse-free for 3 years after allo-HCT who were age ≥16 years at the time of transplantation and age ≥20 years without relapse at the time of the survey. The Medical Outcomes Study's 36-Item Short-Form Survey (SF-36), the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT), and a visual analog scale (VAS) were administered to assess QOL. Physicians evaluated the current status of chronic GVHD at survey using National Institutes of Health (NIH) criteria, and pretransplantation characteristics and history of GVHD were extracted from the national transplant registry database. Patients without currently active GVHD but with a history of chronic GVHD were categorized as having “resolved GVHD.” Of 1250 patients informed of the study, 1216 provided consent and 1130 were included in the final analysis. A total of 745 patients (66%) had currently active chronic GVHD, 149 (13%) had resolved chronic GVHD, and 236 (21%) never had chronic GVHD after allo-HCT. Multivariable analyses showed that compared with patients with resolved or no chronic GVHD, those with active chronic GVHD reported significantly poorer QOL. The QOL scores were similar in patients with resolved chronic GVHD and those without chronic GVHD. Greater between-group differences were observed in SF-36 Physical component and VAS scores in patients age ≥50 years, but the differences were not statistically significant. Our data indicate that only currently active chronic GVHD has a significant impact on physical, mental, and social QOL in allo-HCT survivors, whereas previous chronic GVHD does not impair QOL if it has been resolved.

DOI： 10.1016/j.bbmt.2019.05.016

Open Access

Web of Science

Scopus

PubMed

Language：English   Publisher：European Journal of Cancer  

Background: Fluorouracil (5-FU), leucovorin (LV) and oxaliplatin (FOLFOX) plus panitumumab therapy is a commonly used first-line chemotherapy for metastatic colorectal cancer (mCRC). However, the long-term administration of oxaliplatin is associated with peripheral neuropathy (PN). We investigated whether the planned discontinuation of oxaliplatin after FOLFOX plus panitumumab therapy can maintain efficacy and reduce PN incidence. Patients and methods: Chemotherapy-naive patients with RAS wild-type mCRC, aged ≥20 years, were enrolled and received six cycles of modified FOLFOX6 (mFOLFOX6) plus panitumumab as induction therapy. Patients who completed induction therapy without progression were randomised to mFOLFOX6 plus panitumumab (group A) or to 5-FU/LV plus panitumumab (group B). The primary end-point was the progression-free survival (PFS) rate at 9 months after randomisation. The secondary end-points were PFS, overall survival (OS), time to treatment failure (TTF), response rate (RR) and safety. Results: In total, 164 patients were enrolled; of whom, 113 patients were then randomised (group A, n = 56; group B, n = 57). The median follow-up after randomisation was 19.6 months. The PFS rates at 9 months and median PFS were 46.4% (80% confidence interval [CI], 38.1–54.9) and 9.1 months (95% CI, 8.6–11.1) in group A, compared with 47.4% (80% CI, 39.1–55.8) and 9.3 months (95% CI, 6.0–13.0) in group B, respectively. RR, OS and TTF were also similar in both groups. Grade ≥2 PN incidence was lower in group B (9.3%) than in group A (35.7%). Conclusion: Planned discontinuation of oxaliplatin after six cycles of mFOLFOX6 plus panitumumab is a potential treatment option in patients with mCRC, achieving similar efficacy while reducing oxaliplatin-associated PN compared with mFOLFOX6 plus panitumumab. Trial registration number: NCT02337946

DOI： 10.1016/j.ejca.2019.07.006

Open Access

Scopus

PubMed

Language：Japanese   Publisher：The Japan Society for Precision Engineering  

DOI： 10.11522/pscjspe.2019a.0_530

CiNii Research

Publisher：Optical Materials  

Scintillation and luminescence properties of a novel organic crystal scintillator, 1,4-bis(2-methylstyryl)benzene (bis-MSB), were measured and compared with those of the conventional trans-stilbene organic crystal scintillator. Although trans-stilbene has been used for beta or neutron detection, trans-stilbene cannot be applied at high temperature conditions due to a lower melting point (124 °C). Liquid scintillators or plastic scintillators also cannot be used at high temperature. Usually, bis-MSB has been used as dopant in liquid scintillators to obtain fast scintillation decay and high luminescence quantum yield, and its melting point is 181 °C higher than that of trans-stilbene. In this paper, we focused on bis-MSB in solid state. The bis-MSB and trans-stilbene crystals were grown by the self-seeding vertical Bridgman method using double quartz ampoules. The bis-MSB crystal had the fast decay time of ∼4.2 ns and the increased light yield of ∼12,000 ph/5.5 MeV(α), while trans-stilbene had the decay time of ∼8.5 ns and the light yield of ∼8500 ph/5.5 MeV(α). The photoluminescence quantum yield was almost constant up to 125 °C for bis-MSB and only up to 50 °C for trans-stilbene. We succeeded in obtaining the novel organic crystal scintillator which can operate even at higher temperature up to 125 °C.

DOI： 10.1016/j.optmat.2019.04.051

Web of Science

Scopus

Publisher：Radiation Measurements  

In this study, solid solutions of Ca(Br,I)<inf>2</inf> were prepared to mitigate the cleavage feature of CaI<inf>2</inf>. Samples were grown using the Bridgman–Stockbarger (BS) method in a quartz ampoule. Eu²⁺ 4f–5d emissions were observed, peaking at 462–464 nm with a scintillation decay time of around 1000–1500 ns. Eu2%:CaBr<inf>0.5</inf>I<inf>1.5</inf> showed the best light output of 109,000 photons/MeV, and Eu2%:CaBrI showed the best energy resolution (7.9%@662 keV) among the crystals grown. Eu2%:CaBr<inf>0.5</inf>I<inf>1.5</inf> showed the same crystal phase as CaI<inf>2</inf> and a strong cleavage feature. In contrast, Eu2%:CaBrI did not exhibit the cleavage feature and was more feasible for mass production as a detector material. Eu-doped CaBrI was the most promising material, not only for applications in the observation of neutrinoless double beta decay, but also other high-energy physics, gamma ray surveys, and gamma camera applications, owing to the optimization of light yield and energy resolution without cleavage.

DOI： 10.1016/j.radmeas.2019.106139

Web of Science

Scopus

Publisher：Radiation Measurements  

Pyrosilicate scintillation crystals are expected to be the next generation scintillators, because they have good light output and no hygroscopic nature. In this work, (Ce<inf>0.01</inf> Gd<inf>0.90</inf> Y<inf>0.09</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (Ce:Y-GPS)crystal was grown by the floating zone method. Emission wavelengths of this material were at 360 and 380 nm originated from Ce³⁺ 5d-4f transition, and these emission peaks were located at shorter wavelength side compared with Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> due to the change of the crystal field. Gamma-ray-excited pulse height and scintillation decay measurements showed that Ce:Y-GPS had a light output of 48,000 ± 3000 photons/MeV, FWHM energy resolution of 11.8 ± 0.5% at 662 keV and the decay time components of 42 ± 1 ns (58 ± 2%)and 180 ± 10 ns (42 ± 2%).

DOI： 10.1016/j.radmeas.2019.106123

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Scopus

Language：English  

DOI： 10.1080/09168451.2019.1591262

PubMed

Publisher：Journal of Instrumentation  

(Gd,La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf>:Ce (La-GPS:Ce) is a new scintillator material with high light output, high energy resolution, and fast decay time. Moreover, the scintillator has a good light output even at high temperature (up to 150^◦C) and is non-hygroscopic in nature; thus, it is especially suitable for underground resource exploration. Particle identification greatly expands the possible applications of scintillator. For resource exploration, the particle identification should be completed in a single pulse only. The pulse-shape discrimination of the scintillator was confirmed. We compared two methods: a double gate method and a digital filter method. Using digital filter method (shape indicator), F-measure to evaluate these separation between α and γ particles was obtained to be 0.92 at 0.66 MeVee.

DOI： 10.1088/1748-0221/14/06/P06037

Open Access

Web of Science

Scopus

Publisher：Optical Materials  

The scintillation characteristics of Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce, Li (GAGG:Ce,Li) and Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce, Mg (GAGG:Ce,Mg) single crystals were compared. Radioluminescence spectra and photoluminescence decay curves were measured at various temperatures between 77 and 500 K to investigate the thermal luminescence quenching. At 662 keV γ rays, the LY value of 35,400 photons/MeV and energy resolution of 6.9% obtained for GAGG:Ce, Li are superior to those of 24,200 photons/MeV and 9.5% for GAGG:Ce,Mg. Scintillation decays are approximated by a double exponentials with a fast principal decay component of 47 ns (83%) for GAGG:Ce, Mg and 90 ns (86%) for GAGG:Ce,Li. Coincidence time resolution of 282 ps obtained for GAGG:Ce, Mg is better than that of 389 ps for GAGG:Ce,Li. GAGG:Ce, Mg shows a much lower afterglow and thermally stimulated luminescence intensity with respect to GAGG:Ce,Li.

DOI： 10.1016/j.optmat.2019.04.023

Web of Science

Scopus

Publisher：Radiation Measurements  

Cesium hafnium iodide (CHI) was reported as a novel red-emitting scintillator in our previous article, while optimization of the crystal quality and evaluation of the scintillation performance were insufficient. In this study, a large and transparent CHI single crystalline specimen was obtained using slow crystal growth speed. Coupled with a Si avalanche photo-diode, the full width at half maximum energy resolution was evaluated to be 4.2 ± 0.2% at 662 keV which was the best value among conventional red-emitting scintillators. The scintillation light output, non-proportional response of light output and scintillation decay were also evaluated with a photomultiplier tube.

DOI： 10.1016/j.radmeas.2019.03.005

Web of Science

Scopus

Publisher：Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment  

Ce doped (GdLa) <inf>2</inf> Si <inf>2</inf> O <inf>7</inf> (LaGPS) is a new scintillator which has high light output and is a promising candidate for high resolution radiation imaging detectors. Thus we developed a radiation imaging detector using a LaGPS plate combined with a position sensitive photomultiplier tube (PSPMT) and evaluated the performance. We found that the decay times of LaGPS were different with the types of radiations and the separations of the images of the different types of radiations were possible using pulse shape discrimination. The spatial resolution for Am-241 alpha particles (5.5 MeV) was better than 0.31 mm FWHM and the energy resolution was 11 % FWHM. The spatial resolution for Sr–Y-90 beta particles was ∼0.6 mm FWHM and those for Co-57 gamma photons (122 keV) and Cs-137 X-ray (∼35 keV) were better than 0.6 mm FWHM and ∼0.8 mm FWHM, respectively. The decay times for alpha particles, beta particles, and gamma photons were 143 ns, 124 ns, and 119 ns, respectively. With these different decay times, the separation of alpha particles and gamma photons or beta particles was possible using the pulse shape discrimination. We conclude that the developed LaGPS imaging detector has high resolution for all types of radiations and is also capable of the simultaneous imaging and separating the different types of radiations.

DOI： 10.1016/j.nima.2018.11.056

Web of Science

Scopus

Language：English   Publisher：Bone Marrow Transplantation  

DOI： 10.1038/s41409-018-0343-x

Web of Science

Scopus

PubMed

Publisher：Journal of Electronic Materials  

Undoped and Nb-doped SrTiO <inf>3</inf> /TiO <inf>2</inf> (STO/TO) eutectic solids were fabricated from the melt at a eutectic point of STO and TO by unidirectional solidification. Fabricated undoped and Nb:STO/TO eutectic solids were composed of the TiO <inf>2</inf> rod-like and the SrTiO <inf>3</inf> matrix phases, and the periodic and uniform eutectic morphology could be achieved in the Nb:STO/TO eutectic solids by stable control of the liquid–solid interface during the fabrication. The thermal conductivity of the Nb:STO/TO eutectic solid was less than half of that of the Nb:STO single crystal owing to the decrease of the lattice thermal conductivity by phonon scattering at the grain boundaries. The figures of merit ZT’s of the Nb:STO/TO eutectic solid, parallel and perpendicular to the growth direction, were ∼ 0.007 and ∼ 0.0004, respectively. The small ZT’s are attributable to the higher electrical resistivity originating from the insufficient carrier doping and high electrical resistivity of the TO phase.

DOI： 10.1007/s11664-018-06880-2

Web of Science

Scopus

Language：English   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2019.1.0_493

CiNii Research

Language：Japanese   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2019.1.0_525

CiNii Research

Publisher：Optical Materials  

Ce:(Gd,La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (Ce:La-GPS) and Al co-doped Ce:(Gd,La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (Al,Ce:La-GPS) single crystals were grown by the micro-pulling-down method to improve the mechanical, optical and scintillation properties. In a tensile test, the maximum strain and stress values in the stress-strain curve of the Al,Ce:La-GPS single crystal compared to the Ce:La-GPS single crystal and the result suggests that there is a possibility of the improvement on the mechanical property by Al co-doping. In addition, the light yield of the La-GPS single crystal under γ-ray irradiation was slightly increased and the decay time was accelerated by the Al co-doping.

DOI： 10.1016/j.optmat.2018.07.067

Web of Science

Scopus

Publisher：Optical Materials  

GdTaO<inf>4</inf> and (Gd<inf>1-x</inf>Tb<inf>x</inf>)TaO<inf>4</inf> (x = 0, 0.001, 0.02, 0.04, 0.10, and 0.16) single crystals were grown by the micro-pulling down method. The crystallographic system of the grown crystals was identified to be monoclinic (I2/a), which is the stable low-temperature phase of GdTaO<inf>4</inf>. In the photoluminescence (PL) spectra, intense emission was observed at 549 nm (⁵D<inf>3</inf>→⁷F<inf>4</inf> transition of Tb³⁺) for every Tb doped GdTaO<inf>4</inf>. In the excitation spectra for the 549 nm emission, several excitation paths to the Tb³⁺ were attributed: 4f-4f transitions of Gd³⁺, 4f⁸-4f⁷5d transitions of Tb³⁺ and charge transfer of TaO<inf>4</inf> ³⁻ group. Radiolumincece spectra under X-ray irradiation were taken, and the highest emission peak was observed at 544 nm, which was ascribed to the ⁵D<inf>4</inf>→⁷F<inf>5</inf> transition of Tb³⁺. The Tb 2% doped GdTaO<inf>4</inf> showed the highest emission intensity at the 544 nm, and as increasing dopant concentration, the intensity decreased due to the cross-relaxation of Tb³⁺.

DOI： 10.1016/j.optmat.2018.05.031

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Scopus

Language：English   Publisher：Endocrine Journal  

Soft-drink diabetic ketosis, characterized by acute onset ketosis induced by excessive ingestion of sugar-containing drinks, is often seen in obese, young patients, even with undiagnosed type 2 diabetes. We herein report a 15-year-old obese patient with the apolipoprotein E4/2 phenotype, in whom eruptive xanthomas lead to a diagnosis of soft-drink diabetic ketosis. He developed multiple asymptomatic yellowish papules on the auricles, back, buttocks and the extensor surfaces of the elbows and knees. He initially visited a dermatology clinic and his blood triglyceride and HbA1c levels were found to be 6,490 mg/dL and 16.5%, respectively. He was referred to our hospital for treatment of hyperglycemia and hypertyriglyceridemia. On admission, he had ketonuria and increased blood levels of 3-hydroxybutylate and acetoacetate. He habitually drank 1–3 litters of sweet beverages daily to quench his thirst. Therefore, “soft-drink diabetic ketosis” was diagnosed. Severe hypertriglyceridemia was considered to have been a consequence of impaired insulin action and his apolipoprotein E4/2 phenotype. We treated the diabetic ketosis and hypertriglyceridemia with intensive insulin therapy and a fat-restricted diet. At discharge, he no longer required insulin therapy and his blood glucose levels were controlled with metformin and voglibose. Along with amelioration of the hyperglycemia, triglyceride levels decreased to 247 mg/dL without administration of anti-hyperlipidemia agents. The eruptive xanthoma lesions gradually diminished in size and number and eventually disappeared by 12 months. This case provides an instructive example of eruptive xanthomas serving as a sign of severe dysregulation, not only of lipid, but also glucose, metabolism.

DOI： 10.1507/endocrj.EJ18-0356

Open Access

Web of Science

Scopus

PubMed

Publisher：2019 IEEE Nuclear Science Symposium and Medical Imaging Conference NSS Mic 2019  

Laser-driven neutron source is possible to obtain data with higher energy resolution than accelerator based neutron source. The purpose of this study is to evaluate the neutron pulse width for the energy spectrum emitted by the reaction between charged particles experimentally obtained by LFEX laser and a beryllium neutron production target. Monte Carlo simulation code of PHITS 3.02 was used for neutron pulse width evaluation.Furthermore, we investigate the candidate of scintillator for the detection of neutrons in laser-driven neutron source. It was confirmed that the neutron pulse width of a laser-driven neutron source was shorter than that of the accelerator based neutron source in the keV to MeV region. We also experimentally confirmed that organic scintillator such as p-terphenyl was the candidate for the detection of keV to MeV energy region neutron because of high light output and fast decay.

DOI： 10.1109/nss/mic42101.2019.9059945

Web of Science

Scopus

Web of Science

Publisher：Proceedings of Science  

A liquid scintillator containing a tetrakis (isopropyl acetoacetato) zirconium has been developed for ZICOS experiment. In order to reach the sensitivity T<inf>1</inf>⁰<inf>/</inf>^ν<inf>2</inf> ≥ 10²⁷ years, we have to use tone scale of ⁹⁶Zr and have to reduce 95 % of ²⁰⁸Tl decay background. Using Monte Carlo simulation, we could demonstrate new method using the topological information of Cherenkov light, and could reduce 93 % of ²⁰⁸Tl background with 78 % efficiency for 0νββ signal. For the discrimination of Cherenkov light, the precise spectral pulse shape from Cherenkov lights was directly measured by using sub-MeV electrons from ⁹⁰Sr/⁹⁰Y beta source. The observed shape was clearly different from the shape of scintillation light. The pulse rise and fall (decay) time for Cherenkov light were 0.8 ns and 2.5 ns, respectively. They were actually shorter than those times of scintillation light which were also measured by 1.6 ns and 6.5 ns, respectively. This clear difference of rise time will be used for the pulse shape discrimination in order to select PMT which receive Cherenkov lights, and the topological information due to Cherenkov light will be used for the reduction of backgrounds from ²⁰⁸Tl decay which should be major backgrounds observed around Q-value (3.35MeV) of ⁹⁶Zr neutrinoless double beta decay.

Scopus

Language：English   Publisher：The Laser Society of Japan  

Scintillators are group of materials applied for radiation detection. Among them, heavy inorganic single
crystals are used for detection of gamma rays. In order to avoid doping ion segregation or issues related
to high melting point (more than 2,500 °C), some researchers have focused on transparent ceramics. In
this paper, we review the transparent ceramics scintillators, especially those prepared by spark plasma
sintering method.

DOI： 10.2184/lsj.47.8_433

Open Access

CiNii Research

Publisher：2017 IEEE Nuclear Science Symposium and Medical Imaging Conference NSS Mic 2017 Conference Proceedings  

For MeV gamma-ray astronomy, We have developed an electron-tracking Compton camera (ETCC) as a next generation satellite telescope. Our detector consists of a Comptonscattering target and a scattered gamma-ray absorber. The target is a gaseous Time Projection Chamber (TPC), which uses \mu PIC as the 2-dimensional readout detector, and the absorber is position sensitive scintillation arrays (PSAs). We developed a prototype ETCC and certificated its performance in a groundbased experiment. The prototype ETCC had a sharp PSF of 15° included 50%, 662 keV) at the ARM of 5° and the SPD of 100°. We plan to update the prototype ETCC and observe the electronpositron annihilation line of the galactic center in Australia in early 2018 (SMILE-II +). In the data acquisition (DAQ) system of the prototype ETCC, the dead time is estimated to be \sim 20 % at the trigger rate of \sim 100 Hz in a balloon observation, and the prototype ETCC can work. The SMILE-II + ETCC can also work at the balloon altitude. On the other hand, in the future observation with the ETCC, that has a larger effective area than the effective area of SMILE-II + ETCC, the DAQ rate is expected to be \sim~1 kHz. The dead time gets saturation due to sending data via VME bus and common start system in PSA. To overcome the two problem, we develop a new TPC readout board and a PSA readout unit. We create a test model ETCC which have the new TPC readout boards and the new PSA readout units. Although the dead time is \sim 20 % at 30 Hz with a small ETCC in the prototype DAQ system, the dead time is \sim 20 % at 2 kHz in the new system.

DOI： 10.1109/NSSMIC.2017.8532606

Scopus

Publisher：Japanese Journal of Applied Physics  

Ca<inf>3</inf>TaAl<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> (CTAS) piezoelectric powders were sintered at various temperatures to investigate phase formation. The CTAS powder sintered at 1350 °C was composed of a main phase with a langasite-type structure in addition to two secondary phases, whereas the main phases of the CTAS powders sintered at 1200 and 1300 °C were the secondary phases in X-ray diffraction patterns. CTAS single crystals with a diameter of 1 in. were grown by a Czochralski method using the sintered powders, and CTAS single crystals without impurity phases could be grown using the powder sintered at 1350 °C. A higher sintering temperature of starting materials contributes to the creation of CTAS single crystals without impurity phases.

DOI： 10.7567/JJAP.57.11UD11

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Scopus

Language：English   Publisher：Blood Advances  

In the opinion of the European LeukemiaNet (ELN), nucleophosmin member 1 gene mutation (NPM1 mut)-positive acute myeloid leukemia (AML) with an fms-like kinase 3-internal tandem duplication (FLT3-ITD) allele ratio (AR)<0.5 (low AR) has a favorable prognosis, and allogeneic hematopoietic stem cell transplant (allo-HSCT) in the first complete remission (CR1) period is not actively recommended. We studied 147 patients with FLT3-ITD gene mutation-positive AML, dividing them into those with low AR and those with AR of ≥0.5 (high AR), and examined the prognostic impact according to allo-HSCT in CR1. Although FLT3-ITD AR and NPM1 mut are used in the prognostic stratification, we found that NPM1 mut-positive AML with FLT3-ITD low AR was not associated with favorable outcome (overall survival [OS], 41.3%). Moreover, patients in this group who underwent allo-HSCT in CR1 had a significantly more favorable outcome than those who did not (relapse-free survival [RFS] P = .013; OS P = .003). Multivariate analysis identified allo-HSCT in CR1 as the sole favorable prognostic factor (RFS P< .001; OS P < .001). The present study found that prognosis was unfavorable in NPM1 mut-positive AML with FLT3-ITD low AR when allo-HSCT was not carried out in CR1.

DOI： 10.1182/bloodadvances.2018020305

Open Access

Web of Science

Scopus

PubMed

Language：English   Publisher：Clinical Nutrition  

Background & aims: Although parenteral nutrition (PN) is often used after allogeneic hematopoietic stem cell transplantation (allo-HSCT), there is controversy regarding PN management, for instance in the use of fat emulsion and glucose control (GC). To clarify these issues, we conducted a multi-center prospective study with intensive GC, randomizing the use of fat emulsion after allo-HSCT using a myeloablative conditioning regimen. Methods: The primary endpoint was the cumulative incidence of documented infectious disease, namely bacterial and fungal infection, at day 100 after allo-HSCT. Between August 2007 and March 2012, we enrolled 81 patients at 5 centers. Excluding 5 ineligible patients, 76 patients received the protocol treatment. The target fasting glucose level was 80–110 mg/dL. Results: The median follow-up of surviving patients was 1796 days. The cumulative incidences of documented infectious disease at day 100 were 16% (95% confidence interval [CI] 6–29%) in the no-fat group and 19% (95% CI 8–32%) in the fat group, indicating no significant difference. The mean glucose level at 28 days after allo-HSCT was 107 mg/dL in the no-fat group and 111 mg/dL in the fat group. Grade 3 hyperglycemia (>250 mg/dL) and grade 3 hypoglycemia (<40 mg/dL) occurred in 4 patients each (5.3%). Overall survival and non-relapse mortality rates at 4 years were 75% and 11% in the no-fat group and 69% and 8% in the fat group, respectively. Conclusions: Irrespective of the use of fat emulsion, the long-term clinical outcomes of the enrolled patients were favorable under intensive GC. To further clarify the benefits of GC after allo-HSCT, a prospective study randomizing the level of GC is warranted.

DOI： 10.1016/j.clnu.2017.08.022

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Scopus

PubMed

Web of Science

Publisher：Journal of Crystal Growth  

Fabrication of scintillating eutectic composites by various directional solidification techniques is introduced and discussed in some details. Number of methods widely practiced for the single crystal growth including Czochralski, Bridgman or vertical zone melting, and micro-pulling-down are also acceptable for the production of eutectic materials. Two types of such materials are considered here. These are (1) composites used for neutron scintillators; eutectic materials that consist of high neutron cross section material and efficient scintillator (they do not require regular micro-structure) and (2) high resolution scintillators; eutectic materials that have well ordered rod/fiber structure of one of the phases immersed into matrix of second phase (one of them should be efficient scintillator). In later one, the wave guiding can be established in one of the phases (either matrix or fibers). The composites with fiber structure are supposed to be very promising substances for detecting initial irradiation with high spatial resolution. LiF/LiYF<inf>4</inf> and LiF/CaF<inf>2</inf>:Eu eutectic composites represent first group of the scintillators, but CsI/NaCl and GdAlO<inf>3</inf>/α-Al<inf>2</inf>O<inf>3</inf> correspond to the second one.

DOI： 10.1016/j.jcrysgro.2018.02.032

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Scopus

Language：English   Publisher：The Japan Society of Applied Physics  

DOI： 10.11470/jsapmeeting.2018.2.0_435

CiNii Research

Publisher：Journal of Luminescence  

LiAlO<inf>2</inf> can be considered as a good candidate for neutron scintillator host matrix due to the high Li content and high energy deposit of reaction of ⁶Li isotope with neutron. Low density (2.75 g/cm³) is of advantage to achieve low sensitivity of background gamma radiation in mixed radiation fields. Ti-doped LiAlO<inf>2</inf> shows relatively high neutron light yield comparable to that of the Li-glass standard neutron scintillator. At room temperature the Ti⁴⁺ charge transfer (CT) luminescence at 375 nm with the 2.5 µs decay time is the leading emission process. Besides the CT luminescence host emission at shorter wavelengths (350 nm), defect-related emission at 440 nm and impurity Fe³⁺ luminescence at 740 nm are observed. Their emission spectra, excitation spectra and decay kinetics including temperature dependences were studied. Luminescence mechanism in the material and interplay between the luminescence processes are discussed together with possible role of nonstoichiometry and Mg codoping.

DOI： 10.1016/j.jlumin.2018.04.047

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Language：English  

DOI： 10.1182/bloodadvances.2018020966

PubMed

Language：English   Publisher：Bone Marrow Transplantation  

Polyclonal anti-thymocyte globulins (ATGs) are widely used in allogeneic stem cell transplantation (allo-SCT) for GvHD prophylaxis. ATGs exerted anti-tumor effects in in vitro experiments, but in vivo studies are lacking. We experienced a case of relapsed AML with cells positive for CD7 who underwent haploidentical SCT and unexpectedly achieved a significant reduction of AML cells in the peripheral blood after receiving ATGs before the administration of other drugs in the conditioning regimen. This patient achieved long-term survival after haploidentical SCT. To assess the impact of ATGs on clinical outcomes in patients with AML, we performed a retrospective analysis of allo-SCT for relapsed/refractory AML and divided 132 patients into four groups according to the expression of CD7 in AML cells and use of ATGs as part of the conditioning regimen, as follows: CD7-positive ATG group (n = 15), CD7-positive no-ATG group (n = 32), CD7-negative ATG group (n = 19), and CD7-negative no-ATG group (n = 66). The overall survival rates in the CD7-positive ATG group were significantly higher than those in the CD7-positive no-ATG group, whereas these rates did not differ statistically between the CD7-negative ATG and CD7-negative no-ATG groups. Our results indicate a possible anti-leukemic effect of ATGs against CD7-positive AML in humans.

DOI： 10.1038/s41409-018-0115-7

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PubMed

Publisher：IEEE Transactions on Nuclear Science  

Ce-doped (Gd, La) <inf>2</inf> Si <inf>2</inf> O <inf>7</inf> (Ce:La-GPS) scintillator was found to have a good light output of around 40 000 photons/MeV, while some other parameters have not been determined so far. In order to clarify the cause for such a high light yield, some physical parameters have been estimated in this paper. The bandgap energy of Ce:La-GPS was evaluated to be over 7.13 ± 0.03 eV for (Gd <inf>0.75</inf> , La <inf>0.25</inf> ) <inf>2</inf> Si <inf>2</inf> O <inf>7</inf> . Although Ce:La-GPS had wider bandgap compared with the other oxide scintillators, its light output was larger than values for some other scintillators. Since quantum yield of Ce:La-GPS was as high as around 0.8, the product of transfer efficiency and electron-hole pair generation efficiency was estimated to be around 0.9, which was higher than for the other scintillators. Thus, Ce:La-GPS was suggested to have high the product of transfer efficiency and/or electron-hole pair generation efficiency.

DOI： 10.1109/TNS.2018.2841917

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Publisher：IEEE Transactions on Nuclear Science  

Nondoped Cs<inf>2</inf>HfCl<inf>6</inf> (CHC) and alkaline earth metal-doped CHC (AE:CHC) crystals were grown by the vertical Bridgman-Stockbarger method. The spectra of the AE:CHC under X-ray excitation were similar to those for the AE-free crystal; thus, AE doping did not change emission wavelength of CHC. We determined the light outputs and energy resolutions of nondoped CHC and AE:CHC by measuring pulse-height spectra under 662-keV gamma-ray excitation of a ¹³⁷Cs source. Both light output and energy resolution were deteriorated with AE doping. For example, nondoped CHC had a light output of 44 000 photons/MeV and energy resolution of 5.2%; on the other hand, Sr 0.5 at.%-doped CHC had a light output of only 28 000 photons/MeV and energy resolution of 10%. Scintillation decay also did not change. The nonproportional response values of light output versus gamma-ray energy did not improve in AE:CHC either. Therefore, doped AEs can be responsible for creation of defect trap levels which would hamper the carrier transport in CHC structure.

DOI： 10.1109/TNS.2018.2848474

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Publisher：IEEE Transactions on Nuclear Science  

Submicrometer diameter phase-separated scintillator fibers (PSSFs) were reported and they possessed both the properties of an optical fiber and radiation-to-light conversion. The PSSFs were fabricated using a directionally solidified eutectic system. High-resolution X-ray imaging can be developed using the PSSFs. In this paper, Tb- and Eu-doped GdAlO<inf>3</inf> (GAP)/ α-Al<inf>2</inf>O<inf>3</inf> eutectic scintillator was grown by the micro pulling down method with various growth rates in order to achieve the high light output and the high light-guiding efficiency. Relationship between radioluminescence intensity and dopant concentration of Eu and Tb was investigated. At the optimized dopant concentration, relationship between growth rate, eutectic period structure, diameter of PSSFs, and contrast transfer function was investigated to achieve high-resolution X-ray imaging.

DOI： 10.1109/TNS.2018.2841026

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Publisher：Applied Physics Letters  

To clarify the origin of shallow electron traps in cerium-doped Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> (Ce:GAGG), the optical properties of cerium-doped Lu<inf>3-</inf> <inf>x</inf>Gd<inf>x</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf> crystals were investigated. Absorption spectra for x = 3 exhibited a prominent band at 12 000 cm^-1 when excited by 3.31-eV ultraviolet light. This band has been previously attributed to shallow electron traps at defect complexes associated with oxygen vacancies. When Gd³⁺ ions were replaced with Lu³⁺ ions, the 12 000 cm^-1 band weakened and disappeared completely for Ce:Lu<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>. In addition, thermally stimulated luminescence glow curves were observed. Optically stimulated luminescence indicated that the energy of the conduction band minimum did not change by the presence of Lu³⁺ ions. Thus, the Gd³⁺ ions were important for the formation of shallow electron traps in Ce:GAGG. First-principles calculations implied that Gd³⁺ ions responsible for shallow electron traps formed antisite defects at GAGG octahedral sites. Hence, defect complexes of antisite Gd²⁺ ions adjacent to oxygen vacancies were the most plausible candidates for shallow electron traps in Ce:GAGG.

DOI： 10.1063/1.5043218

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Publisher：2018 Conference on Lasers and Electro Optics Pacific Rim CLEO PR 2018  

We fabricated Ce³⁺: CaF2 thin films with different doping concentration in anticipation of use as a phosphor. We calculated practical doping concentration from lattice distortion and evaluated the optimized doping concentration for high efficiency light emission.

DOI： 10.1364/cleopr.2018.w3a.92

Scopus

Publisher：Japanese Journal of Applied Physics  

CeBr<inf>3</inf> and Pr-doped CeBr<inf>3</inf> (Pr:CeBr<inf>3</inf>) single crystals were grown by the halide-micro-pulling-down method, and the effects of Pr doping on the optical and scintillation properties of the CeBr<inf>3</inf> single crystal were investigated. The emission peaks originating from the 4f-4f transition of Pr³⁺ions were observed in the photoluminescence spectrum of the Pr:CeBr<inf>3</inf> single crystal in addition to the emission peaks related to the 5d-4f transition of Ce³⁺ ions. The decay of fast and slow components under gamma-ray irradiation systematically accelerated with increasing Pr concentration while the light yield decreased.

DOI： 10.7567/JJAP.57.070312

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Publisher：Crystal Growth and Design  

The sealed vertical Bridgman (VB) method is the main technique used to grow SrI<inf>2</inf>(Eu) crystals because SrI<inf>2</inf>(Eu) is very hygroscopic. In this study, we grew SrI<inf>2</inf>(Eu) single crystals with two-inch diameters and four-inch lengths using the VB method equipped with a removable chamber. The SrI<inf>2</inf>(Eu) single crystals were produced by the Liquinert process, which requires careful consideration of the crucible material and growth atmosphere. After a review of available materials, carbon crucibles were selected due to their several advantages over traditional quartz ampules: (1) they are suitable for large size crystal growth due to which they do not require any process for sealing of quartz ampule before the growth; (2) ease in controlling the temperature gradient because carbon crucibles can be heated directly via a high frequency induction heating system; and (3) carbon crucibles can assist in removing oxygen and moisture from the melt. The starting material, seed, and hot zone were prepared inside the glovebox in the removable growth chamber, which was used as the growth unit. This unit was installed in the growth system and heated to the melting point of SrI<inf>2</inf>(Eu) in a high-purity Ar atmosphere. The crucible in the growth chamber was then displaced in the downward direction for crystal growth. Crack-free SrI<inf>2</inf>(Eu) bulk single crystals with two-inch diameters were produced. The crystals were cut into cylindrical specimens (diameter = length = 2 in.), polished, and sealed in an aluminum case with a quartz glass window for evaluation. Negligible self-absorption was observed because of the large length of the crystal. The light output of the SrI<inf>2</inf>(Eu) examined in this study was estimated to be 70 000 photons/MeV, and the calculated energy resolution was 3.4% (662 keV, full width at half-maximum) at room temperature.

DOI： 10.1021/acs.cgd.7b01044

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Language：English   Publisher：Biology of Blood and Marrow Transplantation  

The aim of this study was to develop a new composite endpoint that accurately reflects the long-term success of allogeneic hematopoietic stem cell transplantation (allo-HSCT), as the conventional graft-versus-host disease (GVHD)–free, relapse-free survival (GRFS) overestimates the impact of GVHD. First, we validated current GRFS (cGRFS), which recently was proposed as a more accurate endpoint of long-term transplant success. cGRFS was defined as survival without disease relapse/progression or active chronic GVHD at a given time after allo-HSCT, calculated using 2 distinct methods: a linear combination of a Kaplan-Meier estimates approach and a multistate modelling approach. Next, we developed a new composite endpoint, refractory GRFS (rGRFS). rGRFS was calculated similarly to conventional GRFS treating grade III to IV acute GVHD, chronic GVHD requiring systemic treatment, and disease relapse/progression as events, except that GVHD that resolved and did not require systemic treatment at the last evaluation was excluded as an event in rGRFS. The 2 cGRFS curves obtained using 2 different approaches were superimposed and both were superior to that of conventional GRFS, reflecting the proportion of patients with resolved chronic GVHD. Finally, the curves of cGRFS and rGRFS overlapped after the first 2 years of post-transplant follow-up. These results suggest that cGRFS and rGRFS more accurately reflect transplant success than conventional GRFS. Especially, rGRFS can be more easily calculated than cGRFS and analyzed with widely used statistical approaches, whereas cGRFS more accurately represents the burden of GVHD-related morbidity in the first 2 years after transplantation.

DOI： 10.1016/j.bbmt.2018.02.004

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PubMed

Publisher：Optical Materials  

Scintillation properties of Czochralski-grown Gd<inf>3</inf>(Al<inf>5-x</inf>Ga<inf>x</inf>)O<inf>12</inf>:Ce (x = 2.3, 2.6, 3.0) single crystals were investigated. With increasing Ga content in garnet host, the radioluminescence band due to 5d<inf>1</inf> → 4f emission transition was blue-shifted due to a decrease in the crystal field splitting of the 5 d levels. At 662 keV γ rays, the LY value of 47,000, 55,100 and 51,900 ph/MeV was obtained for Gd<inf>3</inf>Al<inf>2.7</inf>Ga<inf>2.3</inf>O<inf>12</inf>:Ce, Gd<inf>3</inf>Al<inf>2.4</inf>Ga<inf>2.6</inf>O<inf>12</inf>:Ce and Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce, respectively. In spite of a lower LY value, Gd<inf>3</inf>Al<inf>2.7</inf>Ga<inf>2.3</inf>O<inf>12</inf>:Ce shows good energy resolution of 4.1% due to its proportionality of LY. The ratio of LY values under excitation with α- and γ-rays (α/γ ratio) was also determined. The fast component decay time with relative intensity of 146 ns (66%), 142 ns (76%) and 112 ns (76%) was measured in the scintillation decay of Gd<inf>3</inf>Al<inf>2.7</inf>Ga<inf>2.3</inf>O<inf>12</inf>:Ce, Gd<inf>3</inf>Al<inf>2.4</inf>Ga<inf>2.6</inf>O<inf>12</inf>:Ce and Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce, respectively. Good coincidence time resolution of Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce is due to a high initial photon emission rate.

DOI： 10.1016/j.optmat.2018.05.015

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Language：English   Publisher：Bone Marrow Transplantation  

DOI： 10.1038/s41409-017-0082-4

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PubMed

Publisher：Journal of Crystal Growth  

In order to obtain new scintillators with high light output and high effective atomic number (Z<inf>eff</inf>), we performed anion-substitution for Cs<inf>2</inf>HfCl<inf>6</inf> (CHC) scintillator, and then, we succeeded in growing Cs<inf>2</inf>HfI<inf>6</inf> (CHI) single crystalline scintillator. It had Z<inf>eff</inf> of 58, which is the same as that of CHC, and had high light output of ∼70,000 photons/MeV with 700 nm emission. However, its scintillation decay time of ∼2.5 µs was slow for practical use as gamma-ray monitor. In this study, we performed Ce³⁺/Eu²⁺ doping to Hf⁴⁺ site to improve decay time of CHI, introducing the fast 5d-4f luminescence. Ce:CHI and Eu:CHI single crystals were finally obtained by the vertical Bridgman-Stockbarger method. The luminescence spectra of the Ce:CHI and Eu:CHI were very similar to that of the non-doped CHI, which would mean that no 5d-4f luminescence of Ce³⁺/Eu²⁺ was observed. The measured light output and decay time of Ce:CHI were ∼48,000 photon/MeV and 2.3 ± 0.1 µs, respectively. As for Eu:CHI, light output and decay time were ∼69,000 photon/MeV and 2.8 ± 0.1 µs, respectively.

DOI： 10.1016/j.jcrysgro.2018.03.033

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Publisher：Journal of Crystal Growth  

ZnAl<inf>2</inf>O<inf>4</inf> crystals were grown using few starting compositions with various ZnO:AlO<inf>3/2</inf> ratio using an Ir wire seed and Ir + Re crucible under ordinary pressure with Ar + 2%O<inf>2</inf> atmosphere by the radiofrequency heating µ-PD furnace. The ZnAl<inf>2</inf>O<inf>4</inf> spinel single crystal with 4 mm diameter could be successfully grown by the µ-PD method by optimization of starting melt composition considering with Zinc oxide evaporation. During 10 min of growth under normal pressure the formation of ZnAl<inf>2</inf>O<inf>4</inf> single phase observed even at high vapor pressure of ZnO. The transmittance spectra and X-ray locking curve were measured for evaluating of grown ZnAl<inf>2</inf>O<inf>4</inf> crystals quality.

DOI： 10.1016/j.jcrysgro.2018.03.009

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Publisher：Journal of Crystal Growth  

This paper addresses several aspects of the µ-PD growth technology as applied to submillimeter diameter sapphire tubes for UFD application. The μ-PD method has been successfully adapted for single crystal sapphire tube growth. A compound crucible made possible the growth of single crystal sapphire tube as small as around 0.70–0.72 mm in outer diameter and 0.28–0.29 in inner diameter over 160 mm in length at growth rate of 2–4 mm/min along 〈0 0 1〉 direction. An Ir crucible with a die composed of an equivalent hole and Ir wire was heated by RF coil in N<inf>2</inf> atmosphere. The μ-PD method has been successfully adapted for single crystal sapphire tube growth. Grown crystal tube showed good XRC value of 30.2 arcsec.

DOI： 10.1016/j.jcrysgro.2018.03.023

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Publisher：Journal of Alloys and Compounds  

Single crystals of (La<inf>0.25</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> and (La<inf>0.235</inf>Ce<inf>0.015</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> were grown by the Czochralski method. Structure analysis of the single crystals by X-ray diffraction (XRD) revealed that (La<inf>0.25</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> and (La<inf>0.235</inf>Ce<inf>0.015</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> crystalize in monoclinic cells (space group P2<inf>1</inf>/c), a = 5.3905(8) Å, b = 8.5605(11) Å, c = 13.957(2) Å, β = 112.223(6)º, and a = 5.3921(7) Å, b = 8.5688(10) Å, c = 13.9172(14) Å, β = 111.980(5)º, respectively. One of the two different rare-earth sites is preferentially occupied by La and Gd atoms or by La, Ce and Gd atoms, and the other is occupied by Gd atoms only. Peaks attributed to the 4f-4f transitions (⁸S<inf>7/2</inf>–⁶G<inf>7/2</inf> and ⁸S<inf>7/2</inf>–⁶I<inf>x</inf>) of Gd³⁺ and 4f-5d transitions of Ce³⁺ were observed in the absorption spectra of (La<inf>0.25</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> and (La<inf>0.235</inf>Ce<inf>0.015</inf>Gd<inf>0.75</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> single crystals.

DOI： 10.1016/j.jallcom.2018.02.286

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Publisher：Journal of Crystal Growth  

Ce0.5%: Ce:Gd<inf>3</inf>Ga<inf>3</inf>Al<inf>2</inf>O<inf>12</inf>(GGAG) single crystals co-doped with 500at.ppm Li⁺, Na⁺ and K⁺ were grown by using the micro-pulling down method. The smooth Ce⁴⁺ charge transfer absorption below 350 nm and decay time acceleration were observed in Li co-doped sample. Na⁺ and K⁺ co-doping did not show a large effect on the acceleration of decay time compared with Li co-doping. Ce0.5%:GGAG single crystals co-doped with 500 at.ppm Li⁺ were also grown by the Czochralski method. Optical, scintillation properties and timing performance were evaluated to investigate the effect of univalent alkali metal ions co-doping on Ce:GGAG scintillators. The scintillation decay curves were accelerated by Li co-doping: the decay time was significantly accelerated to 54.8 ns (47%) for the faster component and 158 ns (53%) for the slower component. The light output was 94% of the non co-doped Ce:GGAG standard. The coincidence time resolution was improved to 258 ps by Li co-doping.

DOI： 10.1016/j.jcrysgro.2018.03.004

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Publisher：Journal of Crystal Growth  

Eu-doped Li(Ca,Sr)AlF<inf>6</inf> [Eu:LiCSAF] single crystals with various Ca/Sr ratios were grown by the micro-pulling-down method, and their optical and scintillation properties were investigated to reveal the effects of Ca/Sr ratio on optical and scintillation properties of the Eu:LiCSAF single crystals. The Li(Ca<inf>1−</inf> <inf>x</inf> <inf>−</inf> <inf>y</inf>Sr<inf>x</inf>Eu<inf>y</inf>)AlF<inf>6</inf> single crystals could be grown in 0 ≤ x ≤ 0.1, 0.5 ≤ x ≤ 1.0 and y = 0.02 while the Eu:LiCSAF crystals with x = 0.2, 0.25 and 0.4 included two colquiriite-type phases with different lattice parameters. The Li(Ca<inf>1−</inf> <inf>x−y</inf>Sr<inf>x</inf>Eu<inf>y</inf>)AlF<inf>6</inf> single crystal with x = 0.25 and y = 0.02 showed the highest light yield under neutron irradiation.

DOI： 10.1016/j.jcrysgro.2018.03.022

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Publisher：Journal of Crystal Growth  

Pr-doped SrI<inf>2</inf> (Pr:SrI<inf>2</inf>) single crystals with various Pr concentrations were grown by the halide-micro-pulling-down (H-μ-PD) method, and the scintillation properties were investigated. Pr1%:SrI<inf>2</inf> single crystal with high transparency could be grown by the H-μ-PD method while Pr2, 3 and 5%:SrI<inf>2</inf> single crystals included some cracks and opaque parts. In the photoluminescence spectrum of the Pr1%:SrI<inf>2</inf> single crystal, an emission peak originated from the Pr³⁺ ion was observed around 435 nm while the radioluminescence spectra showed an emission peak around 535 nm for the undoped SrI<inf>2</inf> and Pr:SrI<inf>2</inf> single crystals. Light yields of Pr1, 2, 3 and 5%:SrI<inf>2</inf> single crystals under γ-ray irradiation were 7700, 8700, 7200 and 6700 photons/MeV, respectively. Decay times of Pr1 and 2%:SrI<inf>2</inf> single crystals under γ-ray irradiation were 55.9 and 35.0 ns of the fast decay component, and 435 and 408 ns of the slow decay component, respectively.

DOI： 10.1016/j.jcrysgro.2018.02.025

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Publisher：Journal of Crystal Growth  

The fabrication and thermal electromotive force characteristics of Ir/Ir-Rh thermocouples capable of repeated bending deformation are described. Ir and Ir-Rh wires with a diameter of 0.5 mm were fabricated using the alloy-micro-pulling-down method. Scanning electron microscopy and electron backscattering diffraction of the radial cross section of the grown wires were performed to investigate the microstructure and orientation of the crystal grains. At the start of growth, the microstructure was polycrystalline with diameters of several hundred micrometers, while at the 8-m growth point it was found to be monocrystalline. The observed single crystals of pure Ir and Ir-Rh alloy were oriented in the 〈1 1 3〉 and 〈1 1 2〉 directions, respectively, whereas the polycrystalline Ir-Rh samples showed preferential growth in the 〈1 0 0〉 direction. The thermal electromotive force of the fabricated Ir/Ir-Rh thermocouple was measured by the comparison technique and the fixed-point technique, and the thermoelectric power was estimated to be 5.9 μV/°C in the range from 600°C to 1100°C.

DOI： 10.1016/j.jcrysgro.2018.01.018

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Publisher：Japanese Journal of Applied Physics  

The effects of Mg co-doping on the scintillation properties of Ce:Lu<inf>2</inf>Gd<inf>1</inf>(Ga,Al)<inf>5</inf>O<inf>12</inf> (LGGAG) single crystals with different Ga/Al ratios were investigated. Mg co-doped and non co-doped Ce:LGGAG single crystals were grown by the micro-pulling down (μ-PD) method and then cut, polished and annealed for each measurement. Absorption spectra, radioluminescence (RL) spectra, pulse height spectra, and scintillation decay were measured to reveal the effect of Mg co-doping. Ce⁴⁺ charge transfer (CT) absorption band peaking at ∼260nm was observed in Mg co-doped samples, which is in good agreement with previous reports for the Ce⁴⁺ CT absorption band in other garnet-based crystals. The scintillation decay time tended to be accelerated and the light yield tended to be decreased by Mg co-doping at higher Ga concentrations.

DOI： 10.7567/JJAP.57.04FJ06

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Publisher：Journal of Crystal Growth  

Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillation crystals are expected to be used as gamma-ray detectors for high temperature measurement. To realize scintillators for high temperature environment, we investigated (Ce<inf>0.01</inf> Gd<inf>0.59−x</inf> La<inf>0.40</inf> Y<inf>x</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (x = 0.00, 0.05, 0.10, 0.15) single crystals grown by the micro-pulling-down method. The results showed that a 5% Y-admixed Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillator can yield higher light output when compared with Y-free Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillator. The light outputs at 25°C and 175°C were determined to be ∼43,000 and ∼40,000 photons/MeV, respectively. Moreover, 1 inch size 5% Y-admixed Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillator was grown by the Czochralski technique, and its light output at 175°C kept the value of around 95% of the value at 25°C.

DOI： 10.1016/j.jcrysgro.2018.01.016

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Publisher：Journal of Crystal Growth  

Ca<inf>3</inf>Ta(Ga<inf>0.9</inf>Sc<inf>0.1</inf>)<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> langasite-type single crystal with a diameter of 1 in. was grown by Czochralski (Cz) method. Obtained crystal had good crystallinity and its lattice constants exceeded those of Ca<inf>3</inf>TaGa<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> (CTGS) according to the X-ray analysis. A crack-free specimen cut from the grown crystal was used for the measurements of dielectric constant ε<inf>11</inf>^T/ε<inf>0</inf>, electromechanical coupling factor k<inf>12</inf>, and piezoelectric constant d<inf>11</inf>. The accuracies of these measurements were better than those for the crystal grown by micro-pulling-down (μ-PD) method. Substitution of Ga with Sc resulted modification of these constants in the directions opposite to those observed after partial substitution of Ga (of CTGS) with Al. This suggests that increase of |d<inf>14</inf>| was most probably associated with enlargement of average size of the Ga sites. The crystal reported here had greater dimensions as compared to analogous crystals grown by the μ-PD method. As a result, accuracy of determination of acoustic constants of this material may be improved.

DOI： 10.1016/j.jcrysgro.2017.12.041

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Publisher：Advanced Engineering Materials  

Innovative method acceptable for production of Iridium (Ir) and Ruthenium (Ru) metal fibers with high melting point and poor workability is developed using an alloy-micro-pulling-down (A-μ-PD) method and ceramic crucibles with sufficient mechanical and thermal shock resistance. As-grown (as-solidified) Ir and Ru fibers are approximately 1 mm in diameter and their lengths exceed 15 and 0.3 m, respectively. Both Ir and Ru fibers are composed of number of elongated grains oriented along a growth direction, which is attributable to the unidirectional solidification. The flexibility and oxidation resistance of the Ir fiber grown by the A-μ-PD method is considerably improved as compared to a commercial Ir wire made by wire-drawing process.

DOI： 10.1002/adem.201700506

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Publisher：Optical Materials  

A set of non-stoichiometric strontium-hafnate ceramic samples was synthesized by the spark plasma sintering technique from powder precursors of optimized composition. The scintillation and optical properties of ceramic samples were investigated by means of time-resolved luminescence spectroscopy. We measured radioluminescence, photoluminescence excitation and emission spectra as well as luminescence decays excited by UV and soft X-rays, respectively. Multiple annealing was employed to optimize ceramic performance. Furthermore, optical properties of powder and ceramic sample of the same composition were compared. Application potential of studied ceramics in superfast imaging applications is discussed as well.

DOI： 10.1016/j.optmat.2018.01.042

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Language：English   Publisher：Patient Education and Counseling  

Objective: This study was designed to address significant gaps in the predominantly western-centric research literature by examining the influence of gender concordance in medical communication and patient satisfaction within the Japanese context. Methods: New primary care patients (54 male and 49 female) were randomly assigned to study internists (6 males and 5 females). Recorded visits were coded with the Roter Interaction Analysis System (RIAS). Post-visit, patients completed a Japanese version of the Medical Interview Satisfaction Scale (MISS). Results: Female concordant visits showed higher levels of patient-centeredness than all other gender combinations. Female physicians substantially modified their communication based on patient gender while male physicians did not. Gender concordance was associated with higher female, but lower male patient satisfaction relative to gender discordant visits. Conclusion: Contrary to normative experience of medicine as a male dominated profession in Japan, and gender-based power differentials, male-gendered clinical communication is less likely to satisfy male than female patients, while female-gendered communication is positively associated with female patient satisfaction. Practice implications: Patient satisfaction ratings reflect greater gender flexibility in terms of acceptable physician behavior than Japanese norms would suggest.

DOI： 10.1016/j.pec.2017.08.001

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PubMed

Publisher：Applied Physics Letters  

The energy levels of electron traps (namely, defect complexes associated with oxygen vacancies) in Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce (GAGG:Ce) were studied at 12 K using mid-infrared (MIR) light pulses from a free-electron laser (FEL) as the probe light. Ce³⁺ 5d-4f luminescence was stimulated by the MIR light pulse following an ultraviolet light pulse. Stimulation of Ce³⁺ 5d-4f luminescence by MIR light pulses was pronounced above 0.31 eV. This result is consistent with that of previous work based on a trap-mediated luminescence model. It is concluded that the electron trap levels are located 0.31 eV below the bottom of the conduction band. This study demonstrates that MIR-FEL is applicable for the determination of hidden electron trap levels.

DOI： 10.1063/1.5008632

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Web of Science

Language：English   Publisher：The Japan Society of Plasma Science and Nuclear Fusion Research  

<p>This paper presents the study of prospective organic-based materials, trans-stilbene and p-terphenyl, as their potential application for new neutron scintillators. Growth of their single crystals by the self-seeding vertical Bridgman method is reported. And evaluation of grown crystals concerning the composition, optical and luminescence properties, and scintillation performance at room temperature is discussed. Their photo- and radio-luminesce spectra were peaking at 388 and 408 nm, their quantum yield was of 52.4% and 79.7%, and the light yield were of 0.89 and 1.80 times higher than that of GS-20 standard, respectively. The scintillation decay times of 8.2 ns (trans-stilbene) and 5.8 ns (p-terphenyl) were observed as well.</p>

DOI： 10.1585/pfr.13.2405011

Open Access

Scopus

CiNii Research

Language：English   Publisher：Leukemia and Lymphoma  

This study aimed at determining how cytogenetic risk status affects outcomes for patients with acute myeloid leukemia (AML) after undergoing various types of allogeneic hematopoietic cell transplantation (HCT). Of 7812 patients eligible for analysis, cytogenetic risk was classified as favorable for 1088, intermediate for 5025, and poor for 1699. Overall, multivariate analysis showed significant intergroup differences in terms of relapse and survival, with the difference between poor- and intermediate-risk groups being greater than that between favorable- and intermediate-risk groups. Non-relapse mortality was identical for the three groups. Significant effects of cytogenetic risk status on survival were documented irrespective of donor type (related, unrelated, and umbilical cord blood), disease status at the time of transplantation (first or second complete remission, and more advanced disease status), and conditioning intensity (myeloablative and reduced-intensity). Our findings demonstrate robust and constant effects of cytogenetic risk status on survival after allogeneic HCT for patients with AML.

DOI： 10.1080/10428194.2017.1357173

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PubMed

Publisher：Optics Infobase Conference Papers  

We fabricated Ce³⁺:CaF2 thin films with different doping concentration in anticipation of use as a phosphor. We calculated practical doping concentration from lattice distortion and evaluated the optimized doping concentration for high efficiency light emission.

Scopus

Publisher：Proceedings of the 2nd International Symposium on Radiation Detectors and their Uses Isrd 2018  

A feasibility study of an application of scintillation fiber imager to realtime range monitoring system for particle therapy was carried out. Monte Carlo simulation using PHITS suggested that reconstructed vertex distribution shows good correlation with Bragg peak depth, which could allow us to perform realtime range monitoring. As a performance test, scintillation fiber imager successfully provided 2D image of proton beam.

DOI： 10.7566/JPSCP.24.011030

Open Access

Scopus

Publisher：Proceedings of SPIE the International Society for Optical Engineering  

To establish imaging spectroscopy of cosmic gamma-rays from a few hundreds of keV to a few tens MeV, we developed an electron-tracking Compton camera (ETCC). The ETCC consists of a time projection chamber (TPC) and pixelated scintillator arrays (PSAs). The ETCC is superior to conventional gamma-ray imaging detectors of this energy band in that the arrival direction of an incident gamma-ray is firmly determined at one point and realizes high noise rejection efficiency. We performed a campaign to demonstrate the gamma-ray imaging performance of the ETCC at balloon altitude via the sub-MeV gamma-ray imaging loaded-on-balloon experiment 2+ (SMILE-2+). The balloon was launched on April 7, 2018, at 6:26 ACST (UTC +9:30) from Alice Springs, Australia. We performed a level flight for 26 hours at an altitude of 39.6 km. The main observation targets were the Galactic Center region and the Crab Nebula and we succeeded in observing them without any critical problems. The configuration of the flight model ETCC and the housekeeping data are described in detail.

DOI： 10.1117/12.2309920

Web of Science

Scopus

Language：Japanese   Publisher：The Laser Society of Japan  

Compact neutron sources have been used as a various diagnostics such as neutron diffraction, neutron
resonant analysis, and neutron radiography. The developments of the neutron detectors are essential for
all of these applications, while the techniques are strongly dependent on the neutron energy and the aim
of the measurement. This paper reviews neutron detection techniques pertinent to promote compact
neutron source uses. Along with general neutron detection systems with conventional counters for slow
neutrons, we have highlighted detectors for high energy neutrons with high time resolution and high
sensitivity which could be applied in a laser-driven compact neutron source.

DOI： 10.2184/lsj.46.11_634

Open Access

CiNii Research

Language：Japanese   Publisher：Hosokawa Powder Technology Foundation  

DOI： 10.14356/hptf.17511

CiNii Research

Language：Japanese   Publisher：The Physical Society of Japan  

DOI： 10.11316/jpsgaiyo.73.1.0_364

Open Access

CiNii Research

Publisher：Optical Materials  

Melt growth of scintillating halide crystals is reviewed. The vertical Bridgman growth technique is still considered as very popular method that enables production of relatively large and commercially attractive crystals. On the other hand, the micro-pulling-down method is preferable when fabrication of small samples, sufficient for preliminary characterization of their optical and/or scintillation performance, is required. Moreover, bulk crystal growth is also available using the micro-pulling-down furnace. The examples of growths of various halide crystals by industrially friendly melt growth techniques including Czochralski and edge-defined film-fed growth methods are also discussed. Finally, traveling molten zone growth that in some degree corresponds to horizontal zone melting is briefly overviewed.

DOI： 10.1016/j.optmat.2017.03.043

Web of Science

Scopus

Publisher：Aip Advances  

Colquiriite-type Eu-doped LiCaAlF<inf>6</inf> and LiSrAlF<inf>6</inf> (Eu:LiCAF and Eu:LiSAF) scintillator single crystals were grown using Al metal as a starting material to improve the Eu dopant segregation. All Eu:LiCAF and Eu:LiSAF single crystals using Al metal (Eu,Al^M:LiCAF and Eu,Al^M:LiSAF) indicated high transparency and effective segregation coefficients (k<inf>eff</inf>) of Eu2%,Al^M1%:LiCAF and Eu2%,Al^M1%:LiSAF single crystals were significantly improved to the value of 0.40 and 0.99, respectively. EuF<inf>3</inf> starting material reacted with Al metal before colquiriite-type phase was generated. As a result, Eu³⁺ ion in EuF<inf>3</inf> was changed to Eu²⁺ ion which could be incorporated into Ca²⁺ and Sr²⁺ sites easily.

DOI： 10.1063/1.5006996

Open Access

Web of Science

Scopus

Publisher：2017 Conference on Lasers and Electro Optics Pacific Rim CLEO PR 2017  

We report on distribution of Eu ions doped CaF<inf>2</inf> single crystal by measurement of multi-photon luminescence. Distribution of Eu²⁺ and Eu³⁺ ions is measured respectively because the luminescence peak due to Eu²⁺ and Eu³⁺ ions is different. We observed the difference in distribution of Eu²⁺ and Eu³⁺ ions doped CaF<inf>2</inf> which is grown by Annealing method and micro pulling-down method.

DOI： 10.1109/CLEOPR.2017.8119055

Scopus

Publisher：Radiation Measurements  

The development of a real-time dose monitor system is one of the important issues in medical engineering to reduce medical accidents such as overdose or incorrect positioning of the treated human tissue during radiation therapy. One of the challenging solutions is to use an infrared scintillator, which is sufficiently bright so that the light can be detected outside the human tissue. In this study, a novel infrared scintillator, Cr-doped Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf>, was tested with pork meat as a phantom of human tissue to prove its feasibility for the dose monitor. The scintillation photons of Cr:Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf> were observed through even 50-mm thick pork meat. The emission peak originated from d-d emission of Cr³⁺. The emission intensity of Cr:Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf> was approximately 3.5 times larger than that of the conventional infrared scintillator Cr:α-Al<inf>2</inf>O<inf>3</inf>. Moreover, we succeeded in performing the infrared imaging for Cr:Gd<inf>3</inf>Ga<inf>5</inf>O<inf>12</inf> irradiated with alpha-rays using a complementary metal oxide semiconductor camera.

DOI： 10.1016/j.radmeas.2017.03.028

Web of Science

Scopus

Publisher：Annals of Hematology  

The clinical impact of KIT mutations in core binding factor acute myeloid leukemia (CBF-AML) is still unclear. In the present study, we analyzed the prognostic significance of each KIT mutation (D816, N822K, and other mutations) in Japanese patients with CBF-AML. We retrospectively analyzed 136 cases of CBF-AML that had gone into complete remission (CR). KIT mutations were found in 61 (45%) of the patients with CBF-AML. D816, N822K, D816 and N822K, and other mutations of the KIT gene were detected in 29 cases (21%), 20 cases (15%), 7 cases (5%), and 5 cases (4%), respectively. The rate of relapse-free survival (RFS) and overall survival (OS) in patients with D816 and with both D816 and N822K mutations was significantly lower than in patients with other or with no KIT mutations (RFS: p < 0.001, OS: p < 0.001). Moreover, stratified analysis of the chromosomal abnormalities t(8;21)(q22;q22) and inv(16)(p13.1q22), t(16;16)(p13.1;q22) showed that D816 mutation was associated with a significantly worse prognosis. In a further multivariate analysis of RFS and OS, D816 mutation was found to be an independent risk factor for significantly poorer prognosis. In the present study, we were able to establish that, of all KIT mutations, D816 mutation alone is an unfavorable prognostic factor.

DOI： 10.1007/s00277-017-3074-y

Scopus

Language：English   Publisher：Biology of Blood and Marrow Transplantation  

Knowing the impact of chronic graft-versus-host disease (GVHD) on quality of life (QoL) after allogeneic hematopoietic stem cell transplantation (allo-HCT) by GVHD type and severity is critical for providing care to transplant survivors. We conducted a cross-sectional questionnaire study to examine the relationship between patient-reported QoL as measured by the Medical Outcomes Study 36-Item Short-Form Health Survey, Functional Assessment of Cancer Therapy-Bone Marrow Transplant, and visual analogue scale (VAS) and chronic GVHD defined by the National Institutes of Health (NIH) criteria. Recipients of allo-HCT for hematologic disease between 1995 and 2009 aged ≥ 16 years at transplant and ≥20 years at the time of the survey who were relapse-free were eligible. A total of 1140 pairs of patient and physician questionnaires were included in the analysis. By NIH global severity score, QoL scores in all aspects were significantly lower in patients with higher global and organ-specific severity grades, independent of background variables. Compared with patients without GVHD symptoms, those with mild symptoms had impaired physical and general QoL according to global severity score and organ-specific scores except for the genital tract. Mild symptoms in the lungs, gastrointestinal tract, and joints and fascia were associated with clinically meaningful deterioration of physical QoL. VAS scores provided by physicians were generally higher than those provided by patients. Differences between scores reported by patients and physicians were larger for patients with no or mild GVHD symptoms. Our findings based on more than 1000 long-term survivors after HCT enabled us to identify a target of care, informing survivorship care protocols to improve post-transplantation QoL.

DOI： 10.1016/j.bbmt.2017.06.011

Web of Science

Scopus

PubMed

Publisher：Journal of Crystal Growth  

Two iridium crucibles with one and five capillaries at a nozzle were developed for the growth of Ce-doped Y<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> [Ce:YAG] single crystals by the micro-pulling-down [μ-PD] method. The purpose of the study was to examine the effect of the capillary number on the Ce distribution in the radial direction of the crystals. The crystals grown from 2 mol% and 5 mol% Ce-doped YAG melts were then cut perpendicular to the growth direction and polished to produce specimens suitable for the measurement of Ce distribution. The Ce:YAG crystals grown using the crucible with one capillary [Ce:YAG(1 C)] had greater Ce content in the central portion of the crystal when compared to its peripheral parts. On the other hand, in the case of the Ce:YAG crystal grown using the crucible with five capillaries [Ce:YAG(5 C)], the increased Ce concentration was detected in five specimen sections positioned just below the capillaries. The results indicated that increase of the number of capillaries is effective practice that results in an improvement of the radial homogeneity of the single crystals grown by the μ-PD method.

DOI： 10.1016/j.jcrysgro.2016.11.119

Web of Science

Scopus

Publisher：Journal of Materials Science Materials in Electronics  

In this study, Eu and Ce doped LiSrI<inf>3</inf> single crystals were explored and the scintillation performance was reported at the first time. Eu and Ce doped LiSrI<inf>3</inf> single crystals were grown by the Bridgman–Stockbarger method in a quartz ampoule with 3 mm inner diameter. Growth rate was 0.06 mm/min. Circular samples with 1 mm thickness were obtained from the grown crystal. The grown Eu doped LiSrI<inf>3</inf> crystal demonstrated Eu²⁺ 4f–5d emission peak at 420 nm under alpha-ray excitation. In the case of Ce doped one, double emission peaks at 360 and 400 nm were observed. The light yield of the Eu doped LiSrI<inf>3</inf> was around 35,000 photon/MeV for 662 keV gamma-ray and 24,000 photon/5.5 MeV for alpha-ray. Energy resolution of the Eu doped LiSrI<inf>3</inf> was 5.2%@662 keV. Scintillation decay time of the grown Ce and Eu doped LiSrI<inf>3</inf> under 662 keV gamma-ray was 23.8 ns (50%) 212 ns (50%) and 545 ns 100%, respectively.

DOI： 10.1007/s10854-017-7150-9

Web of Science

Scopus

Language：English   Publisher：Haematologica  

Adult T-cell leukemia-lymphoma is a distinct type of peripheral Tcell lymphoma caused by human T-cell lymphotropic virus type I. Although allogeneic stem cell transplantation after chemotherapy is a recommended treatment option for patients with aggressive adult T-cell leukemia-lymphoma, there is no consensus about indications for allogeneic stem cell transplantation because there is no established risk stratification system for transplant eligible patients. We conducted a nationwide survey of patients with aggressive adult T-cell leukemia-lymphoma in order to construct a new, large database that includes 1,792 patients aged 70 years or younger with aggressive adult T-cell leukemialymphoma who were diagnosed between 2000 and 2013 and received intensive first-line chemotherapy. We randomly divided patients into two groups (training and validation sets). Acute type, poor performance status, high soluble interleukin-2 receptor levels (> 5,000 U/mL), high adjusted calcium levels (≥ 12 mg/dL), and high C-reactive protein levels (≥ 2.5 mg/dL) were independent adverse prognostic factors used in the training set. We used these five variables to divide patients into three risk groups. In the validation set, median overall survival for the low-, intermediate-, and high-risk groups was 626 days, 322 days, and 197 days, respectively. In the intermediate- and high-risk groups, transplanted recipients had significantly better overall survival than non-transplanted patients. We developed a promising new risk stratification system to identify patients aged 70 years or younger with aggressive adult T-cell leukemia-lymphoma who may benefit from upfront allogeneic stem cell transplantation. Prospective studies are warranted to confirm the benefit of this treatment strategy.

DOI： 10.3324/haematol.2017.164996

Open Access

Web of Science

Scopus

PubMed

Publisher：IEEE Transactions on Nuclear Science  

Eu:SrI<inf>2</inf> bulk single crystals with 1.5-in diameter were grown using the Bridgman-Stockbarger technique and special-shaped crucibles. We will report on the growth of the 1.5-in size Eu:SrI<inf>2</inf> single crystal and the preliminary test of the same sample cut in size of 10 × 10 × 10 mm³ with polishing. An energy resolution of 3.2% full width at half maximum (FWHM) was obtained for ¹³⁷Cs. After cutting and polishing the grown crystal to the size of 3 × 3 × 3 mm³, 8 × 8 matrix Eu:SrI<inf>2</inf> arrays were fabricated. We made a test module consisting of Eu:SrI<inf>2</inf> arrays, which was optically coupled with position sensitive photomultiplier tube (PSPMT) and multi-pixel photon counter (MPPC) array. The position and energy performance of the test module were evaluated using ¹³⁷Cs and ⁵⁷Co radioactive sources. As a result, we were able to resolve all pixels clearly. A good energy resolution of 6.7% ± 0.7% (FWHM) and 8.2% ± 2.5% (FWHM) for 662 keV was obtained using PSPMT and MPPC arrays, respectively. In the same way, energy resolution of 12.7% ± 1.3% and 14.7% ± 3.4% (FWHM) for 122 keV was obtained using PSPMT and MPPC-array, respectively. These energy resolutions considerably degraded compared with an energy resolution of the single piece of Eu:SrI<inf>2</inf> sample owing to the thinness of the Teflon reflector. This conclusion can be considered as a strong motivation for future research on the choice of reflector materials and structure of the Eu:SrI<inf>2</inf> array.

DOI： 10.1109/TNS.2017.2676769

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Scopus

Publisher：Japanese Journal of Applied Physics  

The temperature dependences of the acoustic properties of Ca<inf>3</inf>Ta(Ga<inf>1-x</inf>Al<inf>x</inf>)<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> [CTGAS(x)] were experimentally studied as a function of the Al substitution content x. Five specimens, i.e., one each of X-, Y-, and Z-, and two rotated Y-cut specimens, were prepared from each crystal ingot of CTGAS(x) (x = 0, 0.25, 0.50, and 0.75) grown by the Czochralski technique. The longitudinal wave and shear wave velocities of CTGAS (x) were measured at three temperatures ranging from 291 to 300 K, then acoustically related physical constants (elastic, piezoelectric, and dielectric constants and coefficient of thermal expansion) were determined at approximately room temperature. The results revealed that the temperature coefficients of all the constants linearly changed with Al content. By one of the calculations using the constants and their temperature coefficients determined in this study, we demonstrated their capability to predict suitable conditions (i.e., cut angle, propagation direction, and chemical composition) for acoustic wave devices although they were determined in a narrow temperature range.

DOI： 10.7567/JJAP.56.07JB03

Web of Science

Scopus

Web of Science

Publisher：Applied Physics Letters  

Gd<inf>3</inf>Al<inf>2</inf>Ga<inf>3</inf>O<inf>12</inf>:Ce (GAGG:Ce) was studied by surface photovoltage spectroscopy using the ultraviolet photoelectron spectroscopy technique with synchrotron radiation and a laser source. The lowest Ce³⁺ 4f level is located below the conduction band minimum by 3.02 eV. This result is supported by the excitation spectrum for photo-stimulated luminescence and is compatible with the value predicted by the vacuum-referred binding energy scheme for GAGG:Ce. It is also found that GAGG:Ce is of the p-type. The information on the energy location of the Ce³⁺ 4f level and majority carrier type provides us with hints on how to improve the optical properties of GAGG:Ce for photonic device applications.

DOI： 10.1063/1.4987141

Web of Science

Scopus

Publisher：Journal of Crystal Growth  

The growth conditions of Ce-doped Gd<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> crystals, using the infrared convergent heating floating zone method, were optimized to make the shape of the crystal-melt interface flat or convex. The shape of the crystal-melt interface, meaning the interface between the molten zone and the grown crystal, was evaluated quantitatively using the convexity (h/r) as a parameter. The h/r value was found to be systematically dependent on the crystal diameter, the focus position of the ellipsoidal mirror for infrared convergent heating, and the lamp power used during crystal growth. For an 8.2-mm-diameter crystal grown using conventional conditions, the h/r value was −0.8, which indicates that the crystal-melt interface had a concave shape. The h/r value increased with the position of the ellipsoidal mirror, going from −0.8 for the −8 mm mirror position, to −0.5 for the +6 mm mirror position. Lastly, when the lamp power increased from 5.8 to 7.0 kW, the h/r value increased from −0.6 to −0.3, which was the maximum value observed, indicating that a flat or convex crystal-melt interface was not obtained.

DOI： 10.1016/j.jcrysgro.2016.11.018

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Scopus

Publisher：Journal of Crystal Growth  

Ce-doped Lu<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillator contains radioactive isotope ¹⁷⁶Lu which causes an unwanted intrinsic background signal. The development of scintillators with reduced Lu concentration were required in some applications. In this study, we developed the Gd admixed lutetium pyrosilicate, where the average ion radius at the rare earth site was similar to the Tm³⁺ ion radius, for which the RE<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (RE=Tm, Yb, Lu) crystal structure is stable from room temperature to melting point. We have grown (Ce<inf>x</inf> Lu<inf>1−x−y</inf> Gd<inf>y</inf>)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> (x=0.01, y=0.00, 0.05, 0.10) single crystals. Their crystal systems were monoclinic with a space group C2/m. The absorption spectra revealed the energy transitions in Ce and Gd ions might be occurred. The light output was degraded and decay time was accelerated comparing the Gd 5% admixed sample with the Gd 10% one.

DOI： 10.1016/j.jcrysgro.2016.10.074

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Scopus

Publisher：Journal of Crystal Growth  

Mg co-doped Ce1%:Gd<inf>3</inf>Ga<inf>x</inf>Al<inf>5−x</inf>O<inf>12</inf> (Ce:GAGG) crystals (x=2.4, 2.7, 3.0) were successfully grown by the Czochralski (Cz) method. Effect of Mg co-doping on the scintillation properties of Ce:GAGG was examined. This study covers measurements of solidification fraction and scintillation properties such as light yield, energy resolution and non-proportionality for each crystal. Pulse-height spectra of various gamma and X-ray sources with energies ranged from 30 keV to 662 keV were measured. Regardless of the presence/absence of Mg dopant, the non-proportionality curves with lower content of gallium in the crystal structure tend to improve. Mg co-doped Ce:GAGG samples did not show a significant difference as compared with non co-doped Ce:GAGG. Mg co-doped crystals with x=2.4 and 2.7 showed the promising scintillation properties of faster decay time and higher energy resolution than those with x=3.0.

DOI： 10.1016/j.jcrysgro.2016.12.054

Web of Science

Scopus

Publisher：Journal of Crystal Growth  

Na co-doped Eu: LiCaAlF<inf>6</inf> (Eu, Na: LiCAF) single crystals were grown by the micro-pulling-down (μ-PD) method, and their optical and scintillation properties were examined to reveal the effects of the Na co-doping. The crystals were single-phase materials demonstrating structure isomorphic with that of undoped LiCAF. To perform the crystals characterization, the specimens with dimensions of several millimeters were cut from highly transparent and crack free fragments of the crystals and polished. It was observed that Na co-doping resulted modification of the transmittance and the excitation spectra, and increased the light yield detected under neutron irradiation.

DOI： 10.1016/j.jcrysgro.2016.11.012

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Scopus

Publisher：Journal of Crystal Growth  

Ca<inf>3</inf>Ta(Ga<inf>1-x</inf>Al<inf>x</inf>)<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> [CTGAS] material is a piezoelectric material belonging to the Langasite-type group (space group: P321).and the CTGAS single crystals (x=0, 0.25, 0.50, 0.75) with a diameter of 1 in. were grown by a Czochralski [Cz] method using an Ir crucible under Ar+2%O<inf>2</inf>. The CTGAS single crystals without any cracks could be grown using a CTGAS seed crystal in the x range of 0≤x≤0.75. Cell parameters, a and c, decrease while the a/c ratio increased with the Al concentration. Piezoelectric constant d<inf>11</inf> and electromechanical coupling factor k<inf>12</inf> for the X-cut specimens of the CTGAS single crystals were increased by the Al substitution.

DOI： 10.1016/j.jcrysgro.2016.10.044

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Scopus

Publisher：Journal of Crystal Growth  

Platinum (Pt) crystalline fibers were grown from the melt by the micro-pulling-down (μ-PD) method using the ZrO<inf>2</inf> ceramics crucible. The diameter of the grown Pt fiber was controlled by the ϕ1 mm outlet made at the bottom of the crucible and the Pt fiber of 0.95±0.03 mm in diameter and over 5 m in length was obtained at 10 mm/min pulling-down rate. In addition, the Pt fiber was grown at 1–110 mm/min pulling rates while the liquid-solid interface reached the bottom of the crucible and the crystal growth became unstable at 120 mm/min pulling rate. Few grain boundaries were observed in the scanning electron microscopy image of the Pt fibers and there were some spots with high intensity in the pole figures.

DOI： 10.1016/j.jcrysgro.2016.10.088

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Scopus

Publisher：Journal of Crystal Growth  

The relationship among lattice constant a, Al content, and acoustic properties were experimentally examined using a plate specimen perpendicular to Y-axis prepared from Ca<inf>3</inf>Ta(Ga<inf>0.75</inf>Al<inf>0.25</inf>)<inf>3</inf>Si<inf>2</inf>O<inf>14</inf> [CTGAS(0.25)] single crystal grown by Czochralski method. As the acoustic properties, leaky surface acoustic wave (LSAW) velocities with different propagation directions, X- and Z-propagations, and longitudinal wave velocity propagating along Y-axis direction were measured by the line-focus-beam/plane-wave ultrasonic-material-characterization (LFB/PW-UMC) system. The measured results of LSAW velocity distributions revealed inhomogeneity in radial direction of the crystal ingot exhibiting lower velocity area at the center of the ingot. In addition, the distributions of lattice constant a and chemical composition (especially Al content) were measured along the radial direction. Abnormal changes suggesting existence of residual stresses concentrated on the central part of the crystal ingot other than the effect of chemical composition change were detected from the relationships among the measured parameters.

DOI： 10.1016/j.jcrysgro.2016.10.040

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Scopus

Publisher：Journal of Crystal Growth  

1 in. diameter Mg 0.05, 0.1, 0.2, 0.5 mol% and Zr 0.015% co-doped Ce1%:GGAG crystals were grown by Cz method. Relationship between Mg concentration and absorption, luminescence, light output, decay time, timing resolution was investigated. Mg 0.2 mol% co-doped sample showed the fastest timing resolution of 165 ps among the Mg-co-doped samples.

DOI： 10.1016/j.jcrysgro.2016.11.026

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Scopus

Publisher：Crystal Research and Technology  

We developed the growth technique of the CeBr<inf>3</inf> scintillator single crystal by a Halide-micro-pulling-down (H-μ-PD) method using a carbon crucible with a die under suitable temperature gradient. Four-types after-heaters with different configurations were prepared to control the temperature gradient around the liquid-solid interface during crystal growth. The high temperature gradient resulted in the stable meniscus during the crystal growth and the CeBr<inf>3</inf> single crystal with high transparency could be obtained. The light yield and the decay time under γ-ray irradiation were ∼68,000 ph/MeV and 19 ns, respectively.

DOI： 10.1002/crat.201600401

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Scopus

Publisher：Optical Materials  

Eu doped LiSrI<inf>3</inf>/LiI eutectics were grown by the Bridgman method in a quartz ample with 4 mm inner diameter. and their directionally solidified eutectic system has been investigated. Growth rate was 0.3 mm/min. The eutectic showed well aligned eutectic structure and optically transparent. Grown Eu doped LiSrI3/LiI eutectic shows 400 nm emission ascribed to Eu²⁺ 4f-5d transition under X-ray excitation. The light yield was around 26,000 photon/MeV for 662 keV gamma-ray and 35,000 photons for 5.5 MeV alpha-ray.

DOI： 10.1016/j.optmat.2017.05.010

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Scopus

Language：English   Publisher：Clinical Colorectal Cancer  

Background In Japan, oxaliplatin (OXA)/5-fluorouracil (5-FU)/leucovorin (LV)—the mFOLFOX6 regimen—is the most frequently used first-line chemotherapy backbone for metastatic colorectal cancer. However, peripheral nerve disorders caused by OXA during mFOLFOX6 therapy can decrease patients’ quality of life. OXA can be safely discontinued from a FOLFOX regimen after 6 cycles during first-line therapy. Also, for patients who discontinue OXA without having experienced peripheral nerve disorders, reintroducing OXA in the later stages of treatment could remain an option. Patients and Methods The study is a phase II, multicenter, open-label, parallel-group, randomized, controlled exploratory study comparing the efficacy and safety of mFOLFOX6 plus panitumumab and 5-FU/LV plus panitumumab in patients with chemotherapy-naïve, unresectable, advanced or recurrent colorectal carcinoma of RAS wild-type (SAPPHIRE; ClinicalTrials.gov identifier, NCT02337946). Eligible patients will receive 6 cycles of mFOLFOX6 plus panitumumab combination therapy, followed by 1:1 randomization to either further treatment with mFOLFOX6 plus panitumumab or discontinuation of OXA and treatment with 5-FU/LV plus panitumumab. Up to 100 randomized patients will receive treatment for approximately 12 months or until any of the criteria for treatment discontinuation have been met. The primary endpoint is progression-free survival rate at 9 months after the day of randomization. The secondary endpoints are progression-free survival, overall survival, response rate, and interval to treatment failure. Safety will be evaluated according to the incidence and severity of adverse events, including the incidence of peripheral nerve and skin disorders. Additional endpoints will include maintenance of performance status, continuation of OXA in the mFOLFOX6 plus panitumumab group, and continuation of panitumumab in both groups.

DOI： 10.1016/j.clcc.2017.02.001

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PubMed

Language：English   Publisher：Bone Marrow Transplantation  

Clinical efficacy of allogeneic hematopoietic cell transplantation (HCT) using reduced-intensity conditioning (RIC) for younger patients remains unclear. We therefore performed a retrospective registry-based study to evaluate outcomes for patients with AML aged between 16 and 49 years who underwent RIC allogeneic HCT. Patients receiving RIC (N=125) showed significantly worse survival than those receiving myeloablative conditioning (MAC; N=1,554) (47.7% for RIC and 54.2% for MAC at 4 years, P=0.047). However, the difference became marginal after adjustment for patient characteristics (P=0.080), and inclusion in the multivariate analysis of the HCT comorbidity index or the propensity score for estimating the likelihood of choosing RIC or MAC further reduced statistical significance (P=0.371 and 0.206, respectively), indicating the existence of a selection bias against RIC. Nevertheless, outcomes for our patients receiving RIC were still acceptable, so that RIC constitutes a potential therapeutic option for younger AML patients who are deemed unsuitable for MAC. Subgroup analyses showed that patients aged between 40 and 49 years as well as those in first or second CR at the time of transplantation exhibited similar outcomes regardless of whether they were treated with RIC or MAC.

DOI： 10.1038/bmt.2016.358

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PubMed

Publisher：Optical Materials  

Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillators have fast decay time and keep high light output even at high temperature (∼150°C). To improve the scintillation properties such as light output and decay time, Ce-doped (Gd, La)<inf>2</inf>Si<inf>2</inf>O<inf>7</inf> scintillators codoped with the divalent ions (e.g. Mg²⁺, Ca²⁺) have been studied. In this study, we focused on the other divalent ions (Sr²⁺ and Ba²⁺), and investigated their effect on the scintillation properties and temperature dependence of light output. The absorption due to Ce⁴⁺ was not observed for Sr or Ba codoping. The light outputs were degraded by Sr²⁺ or Ba²⁺ codoping, while the decay times at room temperature were not changed for the samples codoped with divalent ions. On the other hand, the temperature dependence of light output for Ba-codoped sample was improved, and the light output value at 175°C was 36,000 photons/MeV, which was 93% of that at 25°C.

DOI： 10.1016/j.optmat.2017.02.062

Web of Science

Scopus

Publisher：Journal of Materials Science Materials in Electronics  

Ce-doped garnet-type single crystals with improved dopant distribution were grown by the micro-pulling-down method using a modified Iridium crucible and effects of dopant distribution improvement on the optical and scintillation properties were investigated. Ce-doped Y<inf>3</inf>Al<inf>5</inf>O<inf>12</inf> (Ce:YAG) and Gd<inf>3</inf>(Ga,Al)<inf>5</inf>O<inf>12</inf> (Ce:GGAG) single crystals with improved dopant distribution could be grown by a Iridium crucible with five capillaries (5C). The Ce:YAG and Ce:GGAG single crystals (5C) showed higher transmittance than the single crystals grown by an original Iridium crucible with one capillary (1C). In addition, a clear photo-peak could be observed in the pulse-height spectrum of the Ce:YAG single crystal (5C) under γ-ray irradiation while there was no peak in the spectrum of the Ce:YAG single crystal (1C).

DOI： 10.1007/s10854-017-6696-x

Web of Science

Scopus

Publisher：Journal of Materials Science  

Li-containing materials can be applied as neutron scintillators, and LiBaF<inf>3</inf> can discriminate neutron and gamma rays. Moreover, LIF/LiBaF<inf>3</inf> can have higher cross section of thermal-neutron capture compared with LiBaF<inf>3</inf>. In this study, LiF (82.5 mol%) and (Ba<inf>1−x</inf> RE<inf>x</inf>)F<inf>2</inf> (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF<inf>3</inf>, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF<inf>3</inf> excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5d–4f transition of Ce³⁺. On the other hand, LiF/Eu:LiBaF<inf>3</inf> had two scintillation processes; a sharp emission was originated from ⁶P<inf>7/2</inf> → ⁸S<inf>7/2</inf> transitions in the 4f electronic configuration of Eu²⁺ at 360 nm, and a broad one was attributed to Eu²⁺ trapped exciton recombination at 400–450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons.

DOI： 10.1007/s10853-017-0815-1

Web of Science

Scopus