量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The effect of a magnetic field loaded parallel to the ion-beam track on the generations of reactive oxygen species (ROS) in water was investigated. It was reported that loading magnetic field parallel to the particle beam track exaggerate the biological effects, i.e. cell lethality, of the particle beam. However, the mechanism of the enhanced cell death delivered by a logigudinal magnetic field to the beam track has not been clarified yet.
Local density of •OH generation was estimated by a method based on EPR spin-trapping technique. A series of reaction mixtures containing varying concentrations (0.76‒2278 mM) of DMPO was prepared, and transferred to a polyethylene bag for irradiation. Then, the samples were irradiated 16 Gy of carbon- or iron-beam at the Heavy-Ion Medical Accelerator in Chiba (HIMAC, NIRS/QST, Chiba, Japan) with or without longitudinal magnetic field (0.0, 0.3, or 0.6 T).
O2-dependent and O2-independent H2O2 yield was measured. An aliquot of ultra-pure water was irradiated by carbon-ion beam with or without longitudinal magnetic field. Irradiation experiments were performed under air or hypoxic (<0.5% oxygen) conditions. H2O2 generations in irradiated water samples were quantified by an EPR spin-trapping method, which measures •OH synthesized from H2O2 by the UVB irradiation.
Relatively sparse •OH generations caused by particle beams in waster were not affected with loading magnetic field on beam track. Oxygen dependent H2O2 generation was decreased and oxygen-independent H2O2 generation was increased under loading magnetic field parallel to the beam track. Loading magnetic field parallel to the beam track could make •OH generation denser, or could make reaction of dense •OH increased.
会議概要（会議名, 開催地, 会期, 主催者等）
20th Biennial Meeting of SFRR International (SFRR-I 2021)
Effect of longitudinal magnetic field to the linear particle-beam track on yields of hydroxyl radical and hydrogen peroxide in water
