研究者詳細 - 石川　健治

論文 - 石川　健治

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Brain cell proliferation in adult rats after irradiation with nonequilibrium atmospheric pressure plasma 査読有り Open Access

Yamato, M; Tamura, Y; Tanaka, H; Ishikawa, K; Ikehara, Y; Hori, M; Kataoka, Y

APPLIED PHYSICS EXPRESS 14 巻 ( 6 ) 頁： 067002 2021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

Nonequilibrium atmospheric pressure plasma (NEAPP) has the potential for a wide range of medical applications, including wound healing, blood coagulation, and malignant cell apoptosis. However, its effect on the mammalian central nervous system remains unclear. We studied histological changes in the cerebral cortex of adult rats, following irradiation of the brain surface with NEAPP. NEAPP irradiation made three laminar tissue structures and induced high proliferation of brain-resident immature cells as well as bone marrow-derived cells. These observations indicate that NEAPP irradiation induced rearrangement of cellular and tissue organization, including cell proliferation in the central nervous system in vivo.

DOI： 10.35848/1882-0786/ac03c1

Hydrogen peroxide in lactate solutions irradiated by non-equilibrium atmospheric pressure plasma 査読有り

Liu, Y; Ishikawa, K; Miron, C; Hashizume, H; Tanaka, H; Hori, M

PLASMA SOURCES SCIENCE & TECHNOLOGY 30 巻 ( 4 ) 2021年4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 Sources Science and Technology

A mechanism of hydrogen peroxide (H2O2) generation in plasma-activated lactated Ringer's solution (PAL) has been analyzed. PAL was produced by irradiating a sodium lactate solution, a class of hydroxy acid, with non-equilibrium atmospheric pressure plasma (NEAPP). The concentration of H2O2 generation was dependent on the initial lactate concentrations, which ranged from 0-28 mM. However, the generation of H2O2 was inhibited by higher lactate concentration. The formation of H2O2 is proposed by catalyzed lactate and radicals in aqueous solution, such as OH, H and OO, during the plasma treatments.

DOI： 10.1088/1361-6595/abbbd4

Influences of substrate temperatures on etch rates of PECVD-SiN thin films with a CF<sub>4</sub>/H<sub>2</sub> plasma 査読有り

Hsiao, SN; Nakane, K; Tsutsumi, T; Ishikawa, K; Sekine, M; Hori, M

APPLIED SURFACE SCIENCE 542 巻頁： 148550 2021年3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 Surface Science

The dependence of substrate temperatures (50 to −20 °C) on etch rate in two kinds of PECVD SiN films were investigated by a CF<inf>4</inf>/H<inf>2</inf> mixture plasma. The XRR and XPS results indicate that the chemical composition and film density were almost identical for the films. The FTIR shows that the ratio of N[sbnd]H and Si[sbnd]H groups were found to be significantly different in the SiN films. The N[sbnd]H rich films exhibited a lower etch rate at −20 °C than that observed at room temperature or higher, whereas the Si[sbnd]H rich films showed a higher etch rate at −20 °C. We found that the fluorocarbon thickness was thicker in the Si[sbnd]H rich samples than N[sbnd]H rich samples. The fact suggests that hydrogen originated from the broken Si[sbnd]H bonds enhanced the polymerization, which causes the decrease of etch rate. A thinner fluorocarbon thickness was found in the Si[sbnd]H rich samples at low temperature, which results in the higher etch rate. Angular-resolved XPS indicates that N[sbnd]H bonding formed easier on film surface at −20 °C. These results indicate that the bonding structure and substrate temperature affected the fluorocarbon thickness, fluorine reaction probability and hydrogen dissociation during the SiN etching.

DOI： 10.1016/j.apsusc.2020.148550

Selective etching of SiN against SiO<sub>2</sub> and poly-Si films in hydrofluoroethane chemistry with a mixture of CH<sub>2</sub>FCHF<sub>2</sub>, O<sub>2</sub>, and Ar 査読有り

Hsiao, SN; Ishikawa, K; Hayashi, T; Ni, JW; Tsutsumi, T; Sekine, M; Hori, M

APPLIED SURFACE SCIENCE 541 巻頁： 148439 2021年3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 Surface Science

Gas chemistry has a significant impact on etch selectivity in semiconductor device fabrication, which is important for realization of atomic-scale removal and formation of high-aspect ratio features. To widen the controllable changes in the etchant composition in etching processes, our previous calculation showed the possibility of the controllable generation of CH<inf>2</inf>F and CHF<inf>2</inf> related ions and radicals from a 1,1,2-trifluoroethane (CH<inf>2</inf>FCHF<inf>2</inf>) parent gas. The etch selectivity among silicon nitride (SiN), silicon dioxide (SiO<inf>2</inf>) and poly-Si films using CH<inf>2</inf>FCHF<inf>2</inf> plasma mixed with O<inf>2</inf> and Ar was investigated. The effects of the CH<inf>2</inf>FCHF<inf>2</inf> and O<inf>2</inf> partial pressures on the composition of CHF<inf>2</inf><sup>+</sup> and CH<inf>2</inf>F<sup>+</sup> ions, which were measured with a quadrupole mass spectrometer, and on the possible reactions with respect to the CH<inf>2</inf>FCHF<inf>2</inf> and O<inf>2</inf> mixed gas phase were investigated using quantum chemical calculations. The etch selectivity was investigated through surface etching reactions for SiN, SiO<inf>2</inf>, and poly-Si films.

DOI： 10.1016/j.apsusc.2020.148439

酸素ラジカル処理肥料溶液を用いた殺菌でのピロール化合物の重要性査読有り

岩田直幸, 石川健治, 堀勝, 田中宏昌, 伊藤昌文, 橋爪博司

応用物理学会学術講演会講演予稿集 2021.1 巻 ( 0 ) 頁： 1554 - 1554 2021年2月

かいわれ大根種子の発芽と発芽の成長に対する大気圧プラズマ照射の影響－種子の色と貯蔵の効果査読有り

奥村賢直, 石川健治, 古閑一憲, 白谷正治, ヴィダミルダズィネ, アトリパンカジ

応用物理学会学術講演会講演予稿集 2021.1 巻 ( 0 ) 頁： 1514 - 1514 2021年2月

FOREWORD Mechanistic understanding of cold atmospheric plasma applications 査読有り Open Access

Kurihara, K; Ishikawa, K; Takaki, K; Shiratani, M

JAPANESE JOURNAL OF APPLIED PHYSICS 60 巻 ( 2 ) 2021年2月

Growth inhibition effect on <i>Trypanosoma brucei</i> <i>gambiense</i> by the oxidative stress supplied from low-temperature plasma at atmospheric pressure 査読有り Open Access

Yokoyama, N; Sivakumar, T; Ikehara, S; Akimoto, Y; Yamaguchi, T; Wakai, K; Ishikawa, K; Hori, M; Shimizu, T; Sakakita, H; Ikehara, Y

JAPANESE JOURNAL OF APPLIED PHYSICS 60 巻 ( 2 ) 頁： 020601 2021年2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

Trypanosoma brucei (Tb) is a pathogenic protozoan causing sleeping sickness in humans. Despite little knowledge of how the produced reactive oxygen species (ROS) kills this protozoan, the research on the killing mechanism using chemical compounds and the phagosome in the macrophages has suggested that the protozoan is highly susceptible to the increased oxidative stress. Because the prescribed drug can react with various kinds of molecules and the second produced intermediate compounds, in this study, we clarified the immediate killing effect on Tb in the condition of increased oxidative stress using a low-temperature plasma at atmospheric pressure (LTP) equipment. Results Show the significant growth inhibition of Tb in the LTP-treated medium, the loss of morphological homeostasis with twisted to puffed appearance, and demonstrated the swelled changes on mitochondria and endoplasmic reticulum. In conclusion, this study revealed how the increased oxidative stress kills Tb using LTP technology.

DOI： 10.35848/1347-4065/abd464

Effects of Carbon Nanowalls (CNWs) Substrates on Soft Ionization of Low-Molecular-Weight Organic Compounds in Surface-Assisted Laser Desorption/Ionization Mass Spectrometry (SALDI-MS) 査読有り Open Access

Sakai, R; Ichikawa, T; Kondo, H; Ishikawa, K; Shimizu, N; Ohta, T; Hiramatsu, M; Hori, M

NANOMATERIALS 11 巻 ( 2 ) 頁： 1 - 11 2021年2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：Nanomaterials

Carbon nanowalls (CNWs), which are vertically oriented multi-layer graphene sheets, were employed in surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) measurements to detect low-molecular-weight organic compounds. CNWs substrates with widely different wall-to-wall distances from 142 to 467 nm were synthesized using a radical-injection plasma-enhanced chemical vapor deposition (RI-PECVD) system with nanosecond pulse biasing to a sample stage. When survival yield (SY) values of N-benzylpyridinium chloride (N-BP-Cl) were examined, which is commonly used to evaluate desorption/ionization efficiency, a narrower wall-to-wall distance presented a higher SY value. The highest SY value of 0.97 was realized at 4 mJ/cm<sup>2</sup> for the highest-density CNWs with a wall-to-wall distance of 142 nm. The laser desorption/ionization effect of arginine, an amino acid, was also investigated. When CNWs with a narrower wall-to-wall distance were used, the signal-to-noise (SN) ratios of the arginine signals were increased, while the intensity ratios of fragment ions to arginine signals were suppressed. Therefore, the CNWs nanostructures are a powerful tool when used as a SALDI substrate for the highly efficient desorption/ionization of low-molecular-weight biomolecules.

DOI： 10.3390/nano11020262

Impact of seed color and storage time on the radish seed germination and sprout growth in plasma agriculture 査読有り国際共著 Open Access

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

SCIENTIFIC REPORTS 11 巻 ( 1 ) 頁： 2539 2021年1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

The use of low-temperature plasma for the pre-sowing seed treatment is still in the early stage of research; thus, numerous factors affecting germination percentage, seedling growth, and yield remains unknown. This study aimed to estimate how two critical factors, such as harvest year and seed coat color, affect the percentage of germination and seedling growth after plasma treatment. Radish seeds stored for 2 and 1 year after harvesting (harvested in 2017 and 2018) were sorted into two colors (brown and grey) to investigate the plasma effect on harvest year and seed coat color. We analyzed the amounts of seed phytohormones and antioxidant (γ-tocopherol) were analyzed using mass spectrometry, and physical changes were studied using SEM, EDX, and EPR to understand the mechanism of plasma-induced changes in radish seeds. The obtained results revealed that plasma treatment on seeds affects the germination kinetics, and the maximal germination percentage depends on seed color and the time of seed storage after harvest. Through this study, for the first time, we demonstrated that physical and chemical changes in radish seeds after plasma treatment depends upon the seed color and harvest year. Positive effects of plasma treatment on growth are stronger for sprouts from seeds harvested in 2017 than in 2018. The plasma treatment effect on the sprouts germinated from grey seeds effect was stronger than sprouts from brown radish seeds. The amounts of gibberellin A3 and abscisic acid in control seeds strongly depended on the seed color, and plasma induced changes were better in grey seeds harvested in 2017. Therefore, this study reveals that Air scalar-DBD plasma's reactive oxygen and nitrogen species (RONS) can efficiently accelerate germination and growth in older seeds.

DOI： 10.1038/s41598-021-81175-x

Insights into normothermic treatment with direct irradiation of atmospheric pressure plasma for biological applications 査読有り

Yoshimura S., Otsubo Y., Yamashita A., Ishikawa K.

Japanese Journal of Applied Physics 60 巻 ( 1 ) 頁： 010502 2021年1月

担当区分：最終著者,　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

Characterizing the interactions between plasma and living organisms has become a multidisciplinary topic in the field of low-temperature plasma science and technology. Living organisms are hierarchically comprised of cells, tissues, organs, and organ systems. Adaptive responses are systematically controlled by the state of the surrounding environment, such as when living organisms are irradiated with discharge plasma. This review is written from a biological perspective and focuses on the importance of gas temperature control in nonequilibrium atmospheric pressure plasmas. We discuss the critical parameters associated with direct plasma treatments of living organisms. This review provides an assessment of the status of this research field and addresses the prospects for further developments in understanding the interactions between plasma and living organisms. We address the importance and necessity of normothermic plasma treatment, where an experimental system involving living organisms is controlled at an optimal temperature, which plays a significant role in plasma biology.

DOI： 10.35848/1347-4065/abcbd2

Reduction in photon-induced interface defects by optimal pulse repetition rate in the pulse-modulated inductively coupled plasma 査読有り

Miyoshi Y., Ishikawa K., Sekine M., Hori M., Tatsumi T.

Japanese Journal of Applied Physics 60 巻 ( 1 ) 頁： 010906 2021年1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 ultraviolet photon-induced interface defects that degrade the performance of a semiconductor device are reduced by the optimal pulse repetition rate of a pulse-modulated inductively coupled plasma. The defect density depends on the pulse repetition rates; it takes minimum value at a few hundred pulses s<sup>−1</sup> and peaks at a few k pulses s<sup>−1</sup>. The repetition rate-dependent behavior is suggested to be caused by the transient behavior between the plasma's ON and OFF phases. Note that controlling the transient behavior for reducing the photon-induced damage is essential.

DOI： 10.35848/1347-4065/abd113

Improvement of yield and grain quality by periodic cold plasma treatment with rice plants in a paddy field 査読有り

Hashizume, H; Kitano, H; Mizuno, H; Abe, A; Yuasa, G; Tohno, S; Tanaka, H; Ishikawa, K; Matsumoto, S; Sakakibara, H; Nikawa, S; Maeshima, M; Mizuno, M; Hori, M

PLASMA PROCESSES AND POLYMERS 18 巻 ( 1 ) 頁： 2000181 2021年1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

The application of cold plasma has attracted considerable attention in the field of agriculture. We examined the effects of plasma irradiation and treatment with plasma-activated Ringer's lactate solution (PAL) on rice seedlings in a paddy field. Irradiation during the vegetative growth period increased seedling growth, panicle number, and grain yield. In contrast, treatment during the reproductive growth period had a negative or no effect. Moreover, treatment with PAL solution promoted the growth of the main stem, such as grain number and panicle weight, and grain quality, but the grain yield from the whole plant was decreased. The results suggest that cold plasma treatment of rice seedlings is effective for improving plant growth, grain yield, and grain quality.

DOI： 10.1002/ppap.202000181

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

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