研究者詳細 - 石川　健治

論文 - 石川　健治

分割表示 424 件中 141 - 160 件目／全件表示 >>

Cancer Treatments Using Low-Temperature Plasma 査読有り

Tanaka, H; Mizuno, M; Ishikawa, K; Toyokuni, S; Kajiyama, H; Kikkawa, F; Hori, M

CURRENT MEDICINAL CHEMISTRY 28 巻 ( 41 ) 頁： 8549 - 8558 2021年

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

Low-temperature plasma (LTP) is a partially ionized gas that contains elec-trons, ions, radicals, light, etc. Recently, the bio-medical application of LTP has become a hot topic in plasma science and biological science. Cancer treatment with plasma is the most challenging topic in plasma bio-medical applications. Many in vitro and in vivo ex-periments have been conducted to investigate the anti-tumor effects of LTP. Extracellular reactive oxygen and nitrogen species (RONS) in plasma-activated solutions are key factors for the anti-tumor effects, and amino acid modifications by LTP may affect cellular responses. Intracellular RONS are also key factors for the anti-tumor effects. Various signaling pathways, such as p53 signaling pathways, survival and proliferation signaling pathways, and oxidative stress-dependent signaling pathways are activated by LTP.

DOI： 10.2174/0929867328666210629121731

Numerical analysis of high-electron-density atmospheric pressure argon streamer under a pin-to-plane electrode geometry: Effects of applying voltage polarity 査読有り Open Access

Sato Y., Ishikawa K., Tsutsumi T., Ui A., Akita M., Oka S., Hori M.

47th Eps Conference on Plasma Physics Eps 2021 2021-June 巻頁： 45 - 48 2021年

同軸型誘電体バリア放電におけるプラズマの形成過程の数値解析

佐藤陽介, 宇井明生, 岡将太郎, 堤隆嘉, 石川健治, 森山達行, 堀勝

年次大会 2021 巻 ( 0 ) 頁： S053-01 2021年

Reaction science of layer-by-layer thinning of graphene with oxygen neutrals at room temperature 査読有り

Sugiura, H; Kondo, H; Higuchi, K; Arai, S; Hamaji, R; Tsutsumi, T; Ishikawa, K; Hori, M

CARBON 170 巻頁： 93 - 99 2020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：Carbon

Controlling the layers and in-plane defects in multi-layer graphene is the key to exploiting the extraordinary properties of graphene. Layer-by-layer thinning under high-density oxygen neutrals was observed in situ during room-temperature reaction science using a remote oxygen plasma inside a high-voltage transmission electron microscopy. Even though the etching rate of graphene was higher at the edge than at the basal plane, etching started from both locations. Each etched layer was represented by the plasmon loss intensity in the electron energy loss spectrum. After exposure to the remote oxygen plasma, the electron diffraction pattern for the multi-layer graphene keep clear six-fold diffraction pattern. Raman spectroscopy revealed the formation of defects in multi-layer graphene. The nonthermal reaction of oxygen neutrals required for graphene etching was demonstrated by in situ transmission electron microscopy.

DOI： 10.1016/j.carbon.2020.07.052

Influence of chamber pressure on the crystal quality of homo-epitaxial GaN grown by radical-enhanced MOCVD (REMOCVD) 査読有り

Amalraj, FW; Shimizu, N; Oda, O; Ishikawa, K; Hori, M

JOURNAL OF CRYSTAL GROWTH 549 巻頁： 125863 2020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 Crystal Growth

III-nitride was grown by radical-enhanced metalorganic chemical vapor deposition (REMOCVD) with a very high-frequency electric source 100 MHz, using nitrogen and hydrogen as a source gas free from ammonia gas. Applying radio frequency (RF) power at the top electrode generates activated nitrogen, hydrogen, and other nitrogen species. Homoepitaxial gallium nitride (GaN) growth was studied as a function of chamber pressure by REMOCVD. The grown GaN was characterized by scanning electron microscope (SEM), atomic force microscope (AFM), and double crystal X-ray diffraction (XRD). Ga radicals and N radicals were detected by optical emission spectroscopy (OES) as a function of chamber pressure. The V/III ratio changes with the N<inf>2</inf>*/Ga* ratio, and the step flow growth of GaN was achieved under the chamber pressure of 300 Pa.

DOI： 10.1016/j.jcrysgro.2020.125863

Steering of surface discharges on through-glass-vias combined with high-density nonequilibrium atmospheric pressure plasma generation 査読有り

Sato, Y; Katsuno, K; Odaka, H; Imajyo, N; Ishikawa, K; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 53 巻 ( 43 ) 頁： 534302 2020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

The concept of using a glass substrate with fine through-holes filled with metal, called through-glass-vias (TGVs), for an inner wall of an enclosure of a nonequilibrium atmospheric pressure plasma source was validated to extend its processing area with high plasma densities maintained. When applying the TGV substrate into an inner wall of the plasma source, the generated discharge was less likely to drift along with the gas flow, which resembled the behavior of locally high electric fields of the plasma source, called the creeping mode. The decrease in breakdown voltage was also observed. These phenomena are caused by the TGV areas acting as a steering control material in the enclosure of the plasma source. The location of the TGV areas affected the behavior of the generated plasma. The shape of the plasma was accomplished to arbitrarily and locally control by the placement of TGVs.

DOI： 10.1088/1361-6463/aba1ad

Formation of spherical Sn particles by reducing SnO<sub>2</sub> film in floating wire-assisted H<sub>2</sub>/Ar plasma at atmospheric pressure 査読有り Open Access

Nguyen, TTN; Sasaki, M; Tsutsumi, T; Ishikawa, K; Hori, M

SCIENTIFIC REPORTS 10 巻 ( 1 ) 頁： 17770 2020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：Scientific Reports

A green method to synthesize spherical Sn particles by reducing SnO<inf>2</inf> film in atmospheric-pressure H<inf>2</inf>/Ar plasma at low temperatures for various applications is presented. The floating wire-assisted remotely-generated plasma with a mixture of 0.05% H<inf>2</inf>/Ar gas formed spherical metallic Sn particles by reducing a SnO<inf>2</inf> layer on glass substrate. During the reduction process, H radical density was measured by using vacuum ultraviolet absorption spectroscopy, and plasma properties including electron density and gas temperature were diagnosed by optical emission spectroscopy. The inductively coupled generated plasma with a high electron density of 10<sup>14</sup> cm<sup>−3</sup>, a hydrogen atom density of 10<sup>14</sup> cm<sup>−3</sup>, and a gas temperature of 940 K was obtained at a remote region distance of 150 mm where the SnO<inf>2</inf>/glass substrate was placed for plasma treatment. The process has been modeled on the spherical Sn formation based on the reduction of SnO<inf>2</inf> films using H radicals. Depending on the treatment condition, the total reduction area, where spherical Sn particles formed, was enlarged and could reach 300 mm<sup>2</sup> after 2 min. The substrate temperature affected the expansion rate of the total reduction area and the growth of the Sn spheres.

DOI： 10.1038/s41598-020-74663-z

Roles of Atomic Nitrogen/Hydrogen in GaN Film Growth by Chemically Assisted Sputtering with Dual Plasma Sources 査読有り Open Access

Tanide, A; Nakamura, S; Horikoshi, A; Takatsuji, S; Kimura, T; Kinose, K; Nadahara, S; Nishikawa, M; Ebe, A; Ishikawa, K; Oda, O; Hori, M

ACS OMEGA 5 巻 ( 41 ) 頁： 26776 - 26785 2020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：ACS Omega

The growth of sputtered GaN at low temperature is strongly desired to realize the dissemination of low-cost GaN high electron mobility transistor devices for next-generation communication technology. In this work, the roles of atomic nitrogen (N)/hydrogen (H) in GaN film growth on AlN/sapphire substrates by chemically assisted dual source sputtering are studied at a low growth temperature of 600 °C under a pressure of 2 Pa using vacuum ultraviolet absorption spectroscopy. The lateral growth was strongly enhanced with an appropriate H/N flux ratio of 1.9 at a GaN growth rate of ∼1 μm h-1. X-ray photoelectron spectroscopy measurements indicated that N removal from the grown GaN surface by atomic hydrogen promoted the migration of Ga. A smooth GaN surface was achieved at a suitable N/Ga supply ratio of 53 and a H/N ratio of 1.9 with the addition of 0.5% chlorine to the Ar sputtering gas.

DOI： 10.1021/acsomega.0c03865

Laser-induced-plasma-activated medium enables killing of HeLa cells 査読有り

Kurokawa Y., Takeda K., Ishikawa K., Tanaka H., Hori M.

Applied Physics Express 13 巻 ( 10 ) 2020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：Applied Physics Express

Plasma-activated medium (PAM) is defined as a medium irradiated with non-thermal plasma; multiple in vitro and animal experiments have demonstrated that PAM exhibits anti-tumor effects against various cancers. PAM contains various reactive species that contribute to these anti-tumor effects. To increase the abundance of such reactive species, we used laser-generated plasma (LGP). We used a LGP consisting of 200 ns pulsed plasma with an electron density of approximately 7.0 × 10<sup>18</sup> cm<sup>−3</sup>, which is an extremely high electron density, exceeding those of other atmospheric pressure plasmas. We created a laser-generated-plasma-activated medium (LPAM), and treated HeLa cells with the LPAM in both the presence and absence of catalase. Both with and without catalase, the LPAM treatment yielded strong anti-cancer effects against HeLa cells. Surprisingly, we observed morphological differences between HeLa cells grown in LPAM prepared with and without catalase. These results suggested that LPAM induces the cell death through extracellular hydrogen peroxide-dependent and -independent processes.

DOI： 10.35848/1882-0786/abb68c

Adjusted multiple gases in the plasma flow induce differential antitumor potentials of plasma-activated solutions 査読有り

Nakamura, K; Yoshikawa, N; Yoshihara, M; Ikeda, Y; Higashida, A; Niwa, A; Jindo, T; Tanaka, H; Ishikawa, K; Mizuno, M; Toyokuni, S; Hori, M; Kikkawa, F; Kajiyama, H

PLASMA PROCESSES AND POLYMERS 17 巻 ( 10 ) 頁： 1900259 2020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：Plasma Processes and Polymers

We present a novel plasma system that can generate a plasma-activated medium by changing the proportion of reactive gases such as oxygen, nitrogen, and hydrogen in the plasma flow. The correlation between the biological activity of plasma-activated solutions prepared under multiple plasma gas-flow conditions was evaluated. Mixed nitrogen, in addition to oxygen, in the gas flow is most powerful for producing plasma-activated Ringer's lactate solution against antitumor effects on ovarian cancer cells as compared with oxygen or nitrogen alone. The antitumor effect of plasma-activated solutions is controllable by the modification of the proportion of reactive gases (especially nitrogen and oxygen gases) in the plasma flow. These results suggest that the plasma flow conditions may be one of the candidates for the specifications of the plasma-activated solutions to the therapeutic effect.

DOI： 10.1002/ppap.201900259

Small size gold nanoparticles enhance apoptosis-induced by cold atmospheric plasma via depletion of intracellular GSH and modification of oxidative stress 査読有り Open Access

Jawaid, P; Rehman, MU; Zhao, QL; Misawa, M; Ishikawa, K; Hori, M; Shimizu, T; Saitoh, J; Noguchi, K; Kondo, T

CELL DEATH DISCOVERY 6 巻 ( 1 ) 頁： 83 2020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：Cell Death Discovery

Gold nanoparticles (Au-NPs) have attracted attention as a promising sensitizer owing to their high atomic number (Z), and because they are considered fully multifunctional, they are preferred over other metal nanoparticles. Cold atmospheric plasma (CAP) has also recently gained attention, especially for cancer treatment, by inducing apoptosis through the formation of reactive oxygen species (ROS). In this study, the activity of different sized Au-NPs with helium-based CAP (He-CAP) was analyzed, and the underlying mechanism was investigated. Treating cells with only small Au-NPs (2 nm) significantly enhanced He-CAP-induced apoptosis. In comparison, 40 nm and 100 nm Au-NPs failed to enhance cell death. Mechanistically, the synergistic enhancement was due to 2 nm Au-NPs-induced decrease in intracellular glutathione, which led to the generation of intracellular ROS. He-CAP markedly induced ROS generation in an aqueous medium; however, treatment with He-CAP alone did not induce intracellular ROS formation. In contrast, the combined treatment significantly enhanced the intracellular formation of superoxide (O<inf>2</inf><sup>• −</sup>) and hydroxyl radical (<sup>•</sup>OH). These findings indicate the potential therapeutic use of Au-NPs in combination with CAP and further clarify the role of Au-NPs in He-CAP-aided therapies.

DOI： 10.1038/s41420-020-00314-x

酒米品種イネ栽培における低温プラズマ処理の品質への効果査読有り

水野寛子, 橋爪博司, 北野英己, 阿部明子, 湯浅元気, 堀勝, 東野里江, 榊原均, 松本省吾, 水野正明, 田中宏昌, 石川健治, 仁川進, 前島正義

応用物理学会学術講演会講演予稿集 2020.2 巻 ( 0 ) 頁： 1167 - 1167 2020年8月

Influence of temperature on etch rate of PECVD-SiN films with CF<sub>4</sub>/H<sub>2</sub> plasma 査読有り

Hsiao Shihnan, Nakane Kazuya, Ishikawa Kenji, Tsutsumi Takayoshi, Hori Masaru, Sekine Makoto

JSAP Annual Meetings Extended Abstracts 2020.2 巻 ( 0 ) 頁： 1195 - 1195 2020年8月

Numerical analysis of coaxial dielectric barrier helium discharges: three-stage mode transitions and internal bullet propagation 査読有り Open Access

Sato, Y; Ishikawa, K; Tsutsumi, T; Hori, M

APPLIED PHYSICS EXPRESS 13 巻 ( 8 ) 頁： 086001 2020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

He discharge in a coaxial dielectric barrier discharge (DBD) device develops in three stages: first, a Townsend-glow-type plasma spreads in the region between the electrodes; second, a plasma bullet (streamer type discharge) propagates axially and; third, the bullet transitions into a surface discharge at the dielectric surface. These mode transitions are quite different from planar type DBD, in which one discharge mode basically corresponds to one discharge pulse. From fluid-based numerical analysis, the bullet propagation is obeyed by trapping with strong electric fields induced by grounded electrode underneath the dielectric barrier and by surface charge accumulated on the dielectric surface.

DOI： 10.35848/1882-0786/aba3f2

Plasma Agriculture from Laboratory to Farm: A Review 査読有り Open Access

Attri, P; Ishikawa, K; Okumura, T; Koga, K; Shiratani, M

PROCESSES 8 巻 ( 8 ) 頁： 1002 2020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：Processes

In recent years, non-thermal plasma (NTP) application in agriculture is rapidly increasing. Many published articles and reviews in the literature are focus on the post-harvest use of plasma in agriculture. However, the pre-harvest application of plasma still in its early stage. Therefore, in this review, we covered the effect of NTP and plasma-treated water (PTW) on seed germination and growth enhancement. Further, we will discuss the change in biochemical analysis, e.g., the variation in phytohormones, phytochemicals, and antioxidant levels of seeds after treatment with NTP and PTW. Lastly, we will address the possibility of using plasma in the actual agriculture field and prospects of this technology.

DOI： 10.3390/pr8081002

Non-thermal plasma-activated lactate solution kills U251SP glioblastoma cells in an innate reductive manner with altered metabolism 査読有り

Ishikawa, K; Hosoi, Y; Tanaka, H; Jiang, L; Toyokuni, S; Nakamura, K; Kajiyama, H; Kikkawa, F; Mizuno, M; Hori, M

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 688 巻頁： 108414 2020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：Archives of Biochemistry and Biophysics

Ringer's lactate solution irradiated by non-thermal plasma, comprised of radicals, electrons, and ions, is defined as plasma-activated lactate (PAL). PAL exhibited antitumor effects in glioblastoma U251SP cells, which we termed PAL-specific regulated cell death. In contrast to the oxidative stress condition typical of cells incubated in plasma-activated medium (PAM), U251SP cells treated with Ringer's lactate solution or PAL exhibited changes in intracellular metabolites that were reductive in the redox state, as measured by the ratio of oxidative/reductive glutathione concentrations. In the metabolomic profiles of PAL-treated cells, the generation of acetyl-CoA increased for lipid metabolism from alanine and asparagine. PAL thus induces regulated death of U251SP glioblastoma cells in more innate microenvironments than PAM.

DOI： 10.1016/j.abb.2020.108414

<i>In situ</i> surface analysis of an ion-energy-dependent chlorination layer on GaN during cyclic etching using Ar<SUP>+</SUP> ions and Cl radicals 査読有り

Hasegawa, M; Tsutsumi, T; Tanide, A; Nakamura, S; Kondo, H; Ishikawa, K; Sekine, M; Hori, M

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 38 巻 ( 4 ) 頁： 042602 2020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：Journal of Vacuum Science and Technology A Vacuum Surfaces and Films

Gallium nitride (GaN) semiconductor devices must be fabricated using plasma etching with precise control of the etching depths and minimal plasma-induced damage on the atomic scale. A cyclic process comprising etchant adsorption and product removal may be suitable for this purpose but an understanding of the associated etching surface reactions is required. The present work examined the formation of a chlorinated layer based on Cl radical adsorption on a GaN surface in conjunction with Ar ion irradiation. This research employed beam experiments and in situ x-ray photoelectron spectroscopy. The results show that N atoms are preferentially desorbed during exposure to Ar ions to produce Ga-rich layers at depths of 0.8 and 1.1 nm at an Ar ion dosage on the order of 1016 cm-2 and ion energies of 116.0 and 212.6 eV, respectively. Subsequent exposure of the irradiated Ga-rich layer to Cl radicals removes some Ga atoms and produces a chlorinated layer over the GaN surface. This chlorinated layer has a thickness on the order of 1 nm following Cl radical dosages on the order of 1019 cm-2. This study of plasma-treated surfaces is expected to assist in developing means of controlling the etching depth during the atomic layer etching of GaN via Ar ion bombardment.

DOI： 10.1116/6.0000124

Numerical simulations of stable, high-electron-density atmospheric pressure argon plasma under pin-to-plane electrode geometry: effects of applied voltage polarity 査読有り Open Access

Sato, Y; Ishikawa, K; Tsutsumi, T; Ui, A; Akita, M; Oka, S; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 53 巻 ( 26 ) 頁： 265204 2020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：Journal of Physics D Applied Physics

When applying high-voltage direct current to a pin-to-plane electrode geometry with a distance of 2 mm under atmospheric pressure in argon gas, electrical breakdown forms primary then secondary streamers. The polarity of the applied voltage affects this streamer-propagating phenomenon. Properties such as propagation speed, streamer head size, and plasma generation are parameterized at nanosecond scales by computational simulations of a self-consistent, multi-species, multierature plasma fluid modeling approach. For positive polarity on the pin electrode, streamer-head propagation speeds up and streamer head size increases with increasing applied voltages. However, local electron density at the head decreases. For negative polarity, corona-like discharges form around the pin electrode under low applied voltages, and diffusive steamers form under high applied voltages. Secondary streamers re-propagate from the pin after primary streamer propagation, forming a plasma with a high electron density of 10<sup>21</sup> m<sup>-3</sup> for the positive polarity. We show that low-voltage operations with positive polarity are useful for stable high-electron-density discharges under atmospheric pressure argon.

DOI： 10.1088/1361-6463/ab7df0

In-plane modification of hexagonal boron nitride particles via plasma in solution 査読有り Open Access

Ito, T; Goto, T; Inoue, K; Ishikawa, K; Kondo, H; Hori, M; Shimizu, Y; Hakuta, Y; Terashima, K

APPLIED PHYSICS EXPRESS 13 巻 ( 6 ) 頁： 066001 2020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：Applied Physics Express

In-plane modification of hexagonal boron nitride (hBN) is demonstrated via plasma in solution without acid/base addition. Electron spin resonance spectroscopy clearly reveals an increase in nitrogen vacancies in the hBN plane. This could be a simple route to functionalizing the two-dimensional surface of hBN. Simultaneously, hydroxylation occurs, accompanied by an increase in the zeta potential.

DOI： 10.35848/1882-0786/ab916c

Dry Process FOREWORD 査読有り

Shirafuji, T; Kinoshita, K; Akatsuka, H; Eriguchi, K; Ichikawa, T; Ichiki, T; Ishijima, T; Ishikawa, K; Karahashi, K; Kurihara, K; Sekine, M

JAPANESE JOURNAL OF APPLIED PHYSICS 59 巻 ( SJ ) 2020年6月

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