研究者詳細 - 石川　健治

論文 - 石川　健治

分割表示 365 件中 201 - 220 件目／全件表示 >>

Dynamic analysis of reactive oxygen nitrogen species in plasma-activated culture medium by UV absorption spectroscopy 査読有り国際共著

Brubaker, TR; Ishikawa, K; Takeda, K; Oh, JS; Kondo, H; Hashizume, H; Tanaka, H; Knecht, SD; Bilén, SG; Hori, M

JOURNAL OF APPLIED PHYSICS 122 巻 ( 21 ) 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Applied Physics

The liquid-phase chemical kinetics of a cell culture basal medium during treatment by an argon-fed, non-equilibrium atmospheric-pressure plasma source were investigated using real-time ultraviolet absorption spectroscopy and colorimetric assays. Depth- and time-resolved NO2- and NO3- concentrations were strongly inhomogeneous and primarily driven by convection during and after plasma-liquid interactions. H2O2 concentrations determined from deconvolved optical depth spectra were found to compensate for the optical depth spectra of excluded reactive species and changes in dissolved gas content. Plasma-activated media remained weakly basic due to NaHCO3 buffering, preventing the H+-catalyzed decomposition of NO2- seen in acidic plasma-activated water. An initial increase in pH may indicate CO2 sparging. Furthermore, the pH-dependency of UV optical depth spectra illustrated the need for pH compensation in the fitting of optical depth data.

DOI： 10.1063/1.4999256

Dependence of absolute photon flux on infrared absorbance alteration and surface roughness on photoresist polymers irradiated with vacuum ultraviolet photons emitted from HBr plasma 査読有り

Zhang, Y; Takeuchi, T; Ishikawa, K; Hayashi, T; Takeda, K; Sekine, M; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 12 ) 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

The absolute fluxes of vacuum ultraviolet (VUV) photons emitted from HBr plasma were analyzed and the effects of VUV photons on a photoresist polymer in ArF-excimer-laser (193 nm) lithography were quantitatively investigated on the basis of the infrared spectra attributed to the C=O region. The spectral peak intensity assigned to the methacrylic acid (MAA) in the photoresist drastically decreased owing to the loss of this monomer caused by the irradiation of VUV photons at dosages below 16 - 1016 photons/cm2. X-ray photoelectron spectroscopy observation showed that the removed monomer moved to the surface and generated volatile products that induced a decrease in film thickness. As a consequence, the surface became rough during the early-stage irradiation at dosages lower than 16 - 1016 photons/cm2 owing to the monomer loss of MAA with volatile product formation and subsequent cross-linking reactions.

DOI： 10.7567/JJAP.56.126503

State of the art in medical applications using non-thermal atmospheric pressure plasma 査読有り国際共著

Tanaka H., Ishikawa K., Mizuno M., Toyokuni S., Kajiyama H., Kikkawa F., Metelmann H.R., Hori M.

Reviews of Modern Plasma Physics 1 巻 ( 1 ) 2017年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Reviews of Modern Plasma Physics

Plasma medical science is a novel interdisciplinary field that combines studies on plasma science and medical science, with the anticipation that understanding the scientific principles governing plasma medical science will lead to innovations in the field. Non-thermal atmospheric pressure plasma has been used for medical treatments, such as for cancer, blood coagulation, and wound healing. The interactions that occur between plasma and cells/tissues have been analyzed extensively. Direct and indirect treatment of cells with plasma has broadened the applications of non-thermal atmospheric pressure plasma in medicine. Examples of indirect treatment include plasma-assisted immune-therapy and plasma-activated medium. Controlling intracellular redox balance may be key in plasma cancer treatment. Animal studies are required to test the effectiveness and safety of these treatments for future clinical applications.

DOI： 10.1007/s41614-017-0004-3

Intracellular responses to reactive oxygen and nitrogen species, and lipid peroxidation in apoptotic cells cultivated in plasma-activated medium 査読有り

Furuta, R; Kurake, N; Ishikawa, K; Takeda, K; Hashizume, H; Tanaka, H; Kondo, H; Sekine, M; Hori, M

PLASMA PROCESSES AND POLYMERS 14 巻 ( 11 ) 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plasma Processes and Polymers

A mechanism of the cytotoxicity of plasma-activated medium (PAM) is revealed by examining the intracellular effects of reactive oxygen nitrogen species (RONS) and lipid oxidation. PAM is cell culture medium activated by irradiation using non-equilibrium atmospheric-pressure plasma using pure Ar gas in ambient air. Extracellular RONS in PAM induced the apoptotic death of HeLa cells. Temporal changes in intracellular RONS, such as ONOO−, NO, and (Formula presented.), were analyzed. Intracellular RONS generation in HeLa cells following incubation in PAM triggered activation of the caspase cascade pathway and lipid peroxidation of intracellular membranes to induce apoptosis.

DOI： 10.1002/ppap.201700123

Surface roughening of photoresist after change of the photon/radical and ion treatment sequence 査読有り

Zhang, Y; Takeuchi, T; Ishikawa, K; Takeda, K; Kondo, H; Sekine, M; Hori, M

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 35 巻 ( 6 ) 2017年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films

The formation of surface roughness during ion irradiation was suppressed by photon/radical pretreatment of a photoresist with HBr or H2 plasmas. The opposite sequence of treatment after ion irradiation enhanced the surface roughness. The enhancement of roughness after post-treatment was not correlated with a decrease in the film thickness, reactions of Br radicals at the surface, or with the presence of the amorphous carbon-like layer generated by ion irradiation because similar modification was observed for the pretreatment. Fourier transform infrared spectroscopy analysis revealed that the intensities of peaks originated from the C=O absorption of methacrylic acid and methacrylate groups were decreased by irradiation with vacuum ultraviolet light at wavelengths in the range between 115 and 170 nm emitted from HBr or H2 plasmas. The removal of the C=O groups possibly generated dangling bonds and induced crosslinking reactions of the photoresist polymers. The nonuniformity of crosslinking reactions on the roughened photoresist intensively increased the surface roughness.

DOI： 10.1116/1.4994218

最先端プラズマバイオ技術招待有り査読有り

堀勝，石川健治，近藤隆，田中宏昌，橋爪博司

放射線化学頁： 3 - 14 2017年10月

Crystallization of calcium oxalate dihydrate in a buffered calcium-containing glucose solution by irradiation with non-equilibrium atmospheric pressure plasma 査読有り

Kurake, N; Tanaka, H; Ishikawa, K; Nakamura, K; Kajiyama, H; Kikkawa, F; Mizuno, M; Ikehara, Y; Hori, M

JOURNAL OF APPLIED PHYSICS 122 巻 ( 14 ) 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Applied Physics

Oxalate was synthesized in the glucose solution by irradiation with non-equilibrium atmospheric pressure plasma (NEAPP), in which the NEAPP plume contacted the solution surface, via the generation of several intermediate organic products such as gluconic acid. A thermodynamically unstable phase of calcium oxalate dihydrate crystallized rapidly during incubation of a NEAPP-irradiated glucose solution that contained calcium ions and was buffered at neutral pH. Longer irradiation times increased the growth rate and the number of seed crystals.

DOI： 10.1063/1.5006598

High-durability catalytic electrode composed of Pt nanoparticle-supported carbon nanowalls synthesized by radical-injection plasma-enhanced chemical vapor deposition 査読有り

Imai, S; Kondo, H; Cho, H; Kano, H; Ishikawa, K; Sekine, M; Hiramatsu, M; Ito, M; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 50 巻 ( 40 ) 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics D: Applied Physics

For polymer electrolyte fuel cell applications, carbon nanowalls (CNWs) were synthesized by radical-injection plasma-enhanced chemical vapor deposition, and a high density of Pt nanoparticles (>1012 cm-2) was supported on the CNWs using a supercritical fluid deposition system. The high potential cycle tests were applied and the electrochemical surface area of the Pt nanoparticle-supported CNWs did not change significantly, even after 20 000 high potential cycles. According to transmission electron microscopy observations, the mean diameter of Pt changed slightly after the cycle tests, while the crystallinity of the CNWs evaluated using Raman spectroscopy showed almost no change.

DOI： 10.1088/1361-6463/aa8131

Cold atmospheric helium plasma causes synergistic enhancement in cell death with hyperthermia and an additive enhancement with radiation 査読有り Open Access

Moniruzzaman, R; Rehman, MU; Zhao, QL; Jawaid, P; Takeda, K; Ishikawa, K; Hori, M; Tomihara, K; Noguchi, K; Kondo, T; Noguchi, M

SCIENTIFIC REPORTS 7 巻 ( 1 ) 頁： 11659 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

Cold atmospheric plasmas (CAPs) have been proposed as a novel therapeutic method for its anti-cancer potential. However, its biological effects in combination with other physical modalities remain elusive. Therefore, this study examined the effects of cold atmospheric helium plasma (He-CAP) in combination with hyperthermia (HT) 42 °C or radiation 5 Gy. Synergistic enhancement in the cell death with HT and an additive enhancement with radiation were observed following He-CAP treatment. The synergistic effects were accompanied by increased intracellular reactive oxygen species (ROS) production. Hydrogen peroxide (H2O2) and superoxide (O2•-) generation was increased immediately after He-CAP treatment, but fails to initiate cell death process. Interestingly, at late hour's He-CAP-induced O2•- generation subsides, however the combined treatment showed sustained increased intracellular O2•- level, and enhanced cell death than either treatment alone. He-CAP caused marked induction of ROS in the aqueous medium, but He-CAP-induced ROS seems insufficient or not completely incorporated intra-cellularly to activate cell death machinery. The observed synergistic effects were due to the HT effects on membrane fluidity which facilitate the incorporation of He-CAP-induced ROS into the cells, thus results in the enhanced cancer cell death following combined treatment. These findings would be helpful when establishing a therapeutic strategy for CAP in combination with HT or radiation.

DOI： 10.1038/s41598-017-11877-8

Lipid droplets exhaustion with caspases activation in HeLa cells cultured in plasma-activated medium observed by multiplex coherent anti-Stokes Raman scattering microscopy 査読有り

Furuta, R; Kurake, N; Takeda, K; Ishikawa, K; Ohta, T; Ito, M; Hashizume, H; Tanaka, H; Kondo, H; Sekine, M; Hori, M

BIOINTERPHASES 12 巻 ( 3 ) 頁： 031006 2017年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Biointerphases

The multiplex coherent anti-Stokes Raman scattering microscopy allowed label-free visualization of cytoplasmic lipid droplets (LDs). The LDs, which act to conserve energy storage, are usually accumulated during the normal apoptosis of HeLa cells with activation of caspase-3/7 leading to downregulation of the fatty acid catabolism pathways. During cultivating in nonthermal plasmaactivated medium (PAM), while the activation of caspase-3/7 was induced, the authors found that a dynamic exhaustion of the intracellular LDs, underlying the metabolic mechanism of the PAMinduced apoptotic cell death of HeLa cells.

DOI： 10.1116/1.4997170

Thermally enhanced formation of photon-induced damage on GaN films in Cl<inf>2</inf> plasma 査読有り

Liu Z., Asano A., Imamura M., Ishikawa K., Takeda K., Kondo H., Oda O., Sekine M., Hori M.

Japanese Journal of Applied Physics 56 巻 ( 9 ) 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

Deep ultraviolet (UV) photons emitted from Cl2 plasmas become a critical cause of degradation in both photoluminescence (PL) properties and surface stoichiometry as a result of plasma-induced damage on GaN films in Cl2 plasma etching at high temperatures. The damages were formed thermally by photon-irradiations of plasma UV emissions with wavelengths of >258-306 nm from Cl2 plasma at temperatures greater than 500 °C. The damage were observed with a depth of approximately 3.2 nm. The PL property degraded by the UV emission-induced damage at an early period of plasma etching and reached a constant value.

DOI： 10.7567/JJAP.56.096501

Thermal Cyclic Atomic-Level Etching of Nitride Films: A Novel Way for Atomic-Scale Nanofabrication 査読有り

Shinoda, K; Miyoshi, N; Kobayashi, H; Kurihara, M; Izawa, M; Ishikawa, K; Hori, M

ATOMIC LAYER DEPOSITION APPLICATIONS 13 80 巻 ( 3 ) 頁： 3 - 14 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ECS Transactions

A highly selective, rapid thermal-cyclic atomic-level etching (ALE) process for SiNx films has been developed. The first step of this process is exposing SiNx to hydrofluorocarbon plasma to form an (NH4)2SiF6 layer on the SiNx surface. The second step is rapid thermal annealing with infrared (IR) irradiation to decompose and sublimate the (NH4)2SiF6 layer. Etching of SiNx was observed after the (NH4)2SiF6 layer was removed by thermal annealing. Cyclic etching tests were carried out by repeated plasma exposure and IR irradiation. It was found that the cyclic process is self-limiting because etching depth depends only on the cycle number and not on the plasma exposure time. A high selectivity over SiC2 and poly Si was confirmed. This paper reviews the novel isotropic ALE for nitride films focusing on the surface reaction mechanism investigated by x-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). Isotropic ALE of TiN was also demonstrated using the same approach.

DOI： 10.1149/08003.0003ecst

Reduction of chlorine radical chemical etching of GaN under simultaneous plasma-emitted photon irradiation 査読有り

Liu, ZC; Imamura, M; Asano, A; Ishikawa, K; Takeda, K; Kondo, H; Oda, O; Sekine, M; Hori, M

APPLIED PHYSICS EXPRESS 10 巻 ( 8 ) 2017年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Applied Physics Express

Surface chemical reactions on the GaN surface with Cl radicals are thermally enhanced in the high-temperature Cl2 plasma etching of GaN, resulting in the formation of etch pits and thereby, a roughened surface. Simultaneous irradiation of ultraviolet (UV) photons in Cl2 plasma emissions with wavelengths of 258 and 306nm reduces the surface chemical reactions because of the photodissociation of both Ga and N chlorides, which leads to a suppression of the increase in surface roughness. Compared with Si-related materials, we point out that photon-induced reactions should be taken into account during the plasma processing of wide-bandgap semiconductors.

DOI： 10.7567/APEX.10.086502

Temperature dependence of protection layer formation on organic trench sidewall in H<sub>2</sub>/N<sub>2</sub> plasma etching with control of substrate temperature 査読有り

Fukunaga, Y; Tsutsumi, T; Takeda, K; Kondo, H; Ishikawa, K; Sekine, M; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 7 ) 2017年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

For the etching of organic films in H2/N2 plasma, etched profiles are significantly determined by substrate temperature. Here, we control the substrate temperature variation within 3 °C during processing by modulating the plasma-discharge time. The evolution of the cross-sectional profile of line-and-space patterns was observed every 10s. At 60 and 100 °C, sidewall etching was observed during overetching, but not at 20 °C. During the main etching, the sidewalls were protected by the adsorption of by-products at various temperatures. Moreover, we investigated the temperature dependence of protection layer formation by analyzing the surface components of the organic film. The CN layer formed by N radicals has a protective effect that depends on the components of the CN layer. It was found that the ratio of C-N sp3 to C-N sp2 in the sidewall was highest at 100°C. By evaluating the radical contribution to CN layer formation, C-N sp3 bonds were observed to be formed by ions and radiation-assisted reaction.

DOI： 10.7567/JJAP.56.076202

Intracellular-molecular changes in plasma-irradiated budding yeast cells studied using multiplex coherent anti-Stokes Raman scattering microscopy 査読有り

Furuta, R; Kurake, N; Ishikawa, K; Takeda, K; Hashizume, H; Kondo, H; Ohta, T; Ito, M; Sekine, M; Hori, M

PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 巻 ( 21 ) 頁： 13438 - 13442 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Physical Chemistry Chemical Physics

Interactions between non-equilibrium atmospheric-pressure plasma (NEAPP) and living cells were examined using multiplex coherent anti-Stokes Raman scattering (CARS) microscopy. Our multiplex CARS analyses revealed that NEAPP irradiation generates short-lived radicals that induce a decrease in the mitochondrial activity of budding yeast cells.

DOI： 10.1039/c7cp00489c

Dry Process FOREWORD 査読有り

Ishikawa, K; Kinoshita, K; Higashi, S; Ichiki, T; Karahashi, K; Kuboi, N

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 6 ) 2017年6月

Progress and prospects in nanoscale dry processes: How can we control atomic layer reactions? 査読有り国際共著 Open Access

Ishikawa, K; Karahashi, K; Ichiki, T; Chang, JP; George, SM; Kessels, WMM; Lee, HJ; Tinck, S; Um, JH; Kinoshita, K

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 6 ) 2017年6月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

In this review, we discuss the progress of emerging dry processes for nanoscale fabrication. Experts in the fields of plasma processing have contributed to addressing the increasingly challenging demands in achieving atomic-level control of material selectivity and physicochemical reactions involving ion bombardment. The discussion encompasses major challenges shared across the plasma science and technology community. Focus is placed on advances in the development of fabrication technologies for emerging materials, especially metallic and intermetallic compounds and multiferroic, and two-dimensional (2D) materials, as well as state-of-the-art techniques used in nanoscale semiconductor manufacturing with a brief summary of future challenges.

DOI： 10.7567/JJAP.56.06HA02

Hydrogen peroxide sensor based on carbon nanowalls grown by plasma-enhanced chemical vapor deposition 査読有り

Tomatsu, M; Hiramatsu, M; Foord, JS; Kondo, H; Ishikawa, K; Sekine, M; Takeda, K; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 6 ) 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

Fabrication of an electrochemical sensor for hydrogen peroxide (H2O4) detection was demonstrated. H4O2 is a major messenger molecule in various redox-dependent cellular signaling transductions. Therefore, sensitive detection of H2O2 is greatly important in health inspection and environmental protection. Carbon nanowalls (CNWs) are composed of few-layer graphenes standing almost vertically on a substrate forming a three-dimensional structure. In this work, CNWs were used as a platform for H2O2 sensing, which is based on the large surface area of conducting carbon and surface decoration with platinum (Pt) nanoparticles (NPs). CNWs were grown on carbon fiber paper (CFP) by inductively coupled plasma-enhanced chemical vapor deposition to increase the surface area. Then, the CNW surface was decorated with Pt-NPs by the reduction of H2PtCl6. Cyclic voltammetry results indicate that the Pt-decorated CNW/CFP electrode possesses excellent electrocatalytic activity for the reduction of H2O2. Amperometric responses indicate the high-sensitivity detection capability of the Pt-decorated CNW/CFP electrode for H2O2.

DOI： 10.7567/JJAP.56.06HF03

Growth of InN films by radical-enhanced metal organic chemical vapor deposition at a low temperature of 200 °C 査読有り

Takai, S; Lu, Y; Oda, O; Takeda, K; Kondo, H; Ishikawa, K; Sekine, M; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 6 ) 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

The InN films were deposited on GaN surfaces at a low temperature of 200 °C by radical-enhanced metal organic chemical vapor deposition (REMOCVD). The REMOCVD system can provide N radicals from the plasma of a N2-H2 mixture gas without using ammonia. Two types of GaN substrate, bulk GaN and GaN on Si(111), were used. The growth mode was modeled as a step flow on the basis of surface morphology observation by atomic force microscopy.

DOI： 10.7567/JJAP.56.06HE08

Electron behaviors in afterglow of synchronized dc-imposed pulsed fluorocarbon-based plasmas 査読有り

Ueyama, T; Fukunaga, Y; Tsutsumi, T; Takeda, K; Kondo, H; Ishikawa, K; Sekine, M; Iwata, M; Ohya, Y; Sugai, H; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 56 巻 ( 6 ) 2017年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

Electron behaviors in a pulsed dual radio frequency (RF) capacitively coupled plasma of a mixture of C4F8, O2, and Ar gases, where the DC bias of %300V in the RF-on period was imposed and synchronously increased to %1000V in the RF-off period, were investigated. The synchronous DC bias prolongs the electron density (ne) decay and provides emission of Ar at a wavelength of 750.38nm in early afterglow at 3 μs during the RF-off period of 10 kHz pulse modulation. The rapid ne decay occurred with the electron attachments to the electronegative fluorocarbons, and thus the plasma consisting of positive and negative ions was generated. The DC bias voltage seems to be applied between the electrodes and the positive ions accelerated to the top electrode, and enhanced the secondary electron generation at the top electrode surface in the RF-off period with the ion bombardments, concomitantly with the synchronous emissions.

DOI： 10.7567/JJAP.56.06HC03

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