Effects of thoron inhalation and cyclosporin A treatment on dextran sulfate sodium-induced oxidative damage in mice

田中 歩*; 直江 翔太*; 竹中 伶樹*; 神崎 訓枝; 迫田 晃弘; 山岡 聖典*; 片岡 隆浩*

Acta Medica Okayama (Internet), 79(6), p.421 - 429, 2025/12

https://doi.org/10.18926/AMO/69844

Radon (Rn) or thoron (Rn, Tn) inhalation enhances the antioxidant activity in some organs. However, the effects of thoron on the colon have not been reported. This study aimed to clarify the effects of thoron inhalation, alone and in combination with Cyclosporin A (CsA), on oxidative stress and colitis induced by dextran sulfate sodium (DSS) in mice. The mice were subjected to 8-day thoron inhalation (c-Tn) or thoron inhalation every other day (f-Tn) at a concentration of 500 Bq/m. The mice were then administered a combination of 3% DSS and CsA or vehicle for 7 d. Although the disease activity index (DAI) reduced significantly by day 2 in the c-Tn group, the score was significantly higher than that in the f-Tn group. Superoxide dismutase activity in the colons of both the c-Tn and f-Tn group mice and catalase activity in the c-Tn group mice were significantly higher than those in the sham groups. These observations suggest that DSS-induced colitis was effectively inhibited in the earlier stages by the c-Tn mode of inhalation than by the f-Tn mode. This could be attributed to the activation of antioxidant functions by c-Tn inhalation. Furthermore, thoron inhalation and CsA treatment showed no combined effects.

Progress in linac beam commissioning for high-intensity operations for J-PARC power upgrades

Liu, Y.*; 大谷 将士*; 宮尾 智章*; 中沢 雄河*; 柴田 崇統*; 南茂 今朝雄*; Fang, Z.*; 二ツ川 健太*; 福井 佑治*; 溝端 仁志*; et al.

Proceedings of 16th International Particle Accelerator Conference (IPAC25) (Internet), p.855 - 857, 2025/11

https://doi.org/10.18429/JACoW-IPAC2025-TUAD1

The Japan Proton Accelerator Research Complex (J-PARC) has achieved stable 1 MW operation on its neutron target and is advancing toward higher power levels of 1.5 MW to support high-power MR operations and a second target station. This progression presents challenges, including increased intra-beam stripping (IBSt) of negative hydrogen ions, chop leakage from higher beam currents and emittance, low-energy beam loss due to halo formation, frontend fluctuations affecting beam transmission, and RF phase and amplitude fluctuations. To address these issues, a redesigned lattice mitigates IBSt, a new MEBT1 improves chopping and collimation, and machine learning-based compensation schemes manage frontend and RF fluctuations. Additionally, longitudinal and transverse matching schemes enhance beam quality, validated through benchmarked longitudinal measurements. Results from studies at 50 mA and 60 mA beam currents demonstrate significant progress in overcoming these challenges.

地質環境の長期安定性に関する研究 年度計画書(令和7年度)

浅森 浩一; 末岡 茂; 小松 哲也; 小形 学; 内田 真緒; 西山 成哲; 田中 桐葉; 小林 智晴; 三ツ口 丈裕; 村上 理; et al.

JAEA-Review 2025-035, 29 Pages, 2025/10

JAEA-Review-2025-035.pdf:1.12MB

本計画書では、高レベル放射性廃棄物の地層処分技術に関する研究開発のうち、深地層の科学的研究の一環として実施している地質環境の長期安定性に関する研究について、第4期中長期目標期間(令和4年度令和10年度)における令和7年度の研究開発計画を取りまとめた。本計画の策定にあたっては、これまでの研究開発成果や大学等で行われている最新の研究成果に加え、地層処分事業実施主体や規制機関等の動向を考慮した。研究の実施にあたっては、地層処分事業における概要・精密調査や国の安全規制に対し研究成果を適時反映できるよう、(1)調査技術の開発・体系化、(2)長期予測・影響評価モデルの開発、(3)年代測定技術の開発の三つの枠組みで研究開発を推進する。

State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex

Saha, P. K.; 原田 寛之; 田村 文彦; 岡部 晃大; 吉本 政弘; 菖蒲田 義博; 沖田 英史; 小島 邦洸; 仲野谷 孝充; 畠山 衆一郎; et al.

Physical Review Accelerators and Beams (Internet), 28(7), p.074201_1 - 074201_23, 2025/07

https://doi.org/10.1103/tbyh-jcq3

In this research, the beam loss in the J-PARC 3-GeV Rapid Cycling Synchrotron (RCS) has been significantly mitigated at the designed 1 MW beam power. It was possible by identifying all beam loss sources and implementing appropriate measures based on numerical simulations and systematic beam studies. The major one includes of using a smaller size charge-exchange foil and optimizing the injection beam to minimize foil scattering uncontrolled beam loss, modifications of the transverse and longitudinal beam painting parameters to mitigate the high-intensity effects. The beam loss as compared to 1 MW trial operation in 2020 was 80% reduced and perfectly localized at the designated collimator area. The beam loss power is only less than 0.1 kW as compared to the collimator limit of 4 kW. As a result. the residual radiation throughout the ring is substantially reduced for achieving a sustainable operation of the RCS with nearly 99% availability.

Gapless dispersive continuum in a modulated quantum kagome antiferromagnet

Thennakoon, A.*; 横倉 涼雅*; Yang, Y.*; 梶本 亮一; 中村 充孝; 林 真弘*; 道岡 千城*; Chern, G.-W.*; Broholm, C.*; 植田 浩明*; et al.

Nature Communications (Internet), 16, p.3939_1 - 3939_13, 2025/04

https://doi.org/10.1038/s41467-025-58971-4

The pursuit of quantum spin liquid (QSL) states in condensed matter physics has drawn attention to kagome antiferromagnets (AFM) where a two-dimensional corner-sharing network of triangles frustrates conventional magnetic orders. While quantum kagome AFMs based on Cu (, ) ions have been extensively studied, there is so far little work beyond copper-based systems. Here we present our bulk magnetization, specific heat and neutron scattering studies on single crystals of a new titanium fluorides CsRbKTiF where Ti (, ) ions form a modulated quantum kagome antiferromagnet that does not order magnetically down to 1.5 K. Our comprehensive map of the dynamic response function acquired at 1.5 K where the heat capacity is -linear reveals a dispersive continuum emanating from soft lines that extend along (100). The data indicate fractionalized spinon-like excitations with quasi-one-dimensional dispersion within a quasi two-dimensional spin system.

Potential of the young age reference materials; CA-ID-TIMS U-Pb dates of Cenozoic zircons in Japan

長田 充弘; 福田 将眞; 末岡 茂; 中嶋 徹; 横山 立憲; Wall, C. J.*; 檀原 徹*; 岩野 英樹*; 田上 高広*

フィッション・トラックニュースレター, (37), p.11 - 13, 2024/12

近年、分析技術の発達により100万年以降の若い地質単元でもジルコンによるU-Th-Pb年代測定が可能となりつつある。しかしながら、その分析を評価しうる若い標準試料はほとんどない。本研究では、著者らが研究をすすめている100万年オーダーのジルコン試料(TRG04とOGPK)を対象に、同位体希釈表面電離質量分析(ID-TIMS)法によるU-Pb年代測定を試みた。その結果、それぞれ予察的に2.66540.0016Maおよび1.12660.0014MaのU-Pb年代を得た。

Effect of sample temperature and laser ablation angle on optical emission and acoustic signals from laser-induced Zirconium plasma

Batsaikhan, M.; 大場 弘則; 狩野 貴宏; 赤岡 克昭; 若井田 育夫

Optics Express (Internet), 32(24), p.42624 - 42638, 2024/11

https://doi.org/10.1364/OE.538774

A fiber-coupled, acoustic-wave-assisted microchip laser-induced breakdown spectroscopy system (AW-mLIBS) was developed to analyze the elemental composition and surface imaging. In this study, we measured the dependence of sample temperature and laser ablation angle on the laser-induced plasma-optical emission and LIP-acoustic signal. The intensity of the laser-induced plasma-optical emission and ablated mass at three different temperatures and eight different laser ablation angles were estimated using a zirconium sample. Simultaneously, we investigated the laser-induced plasma-acoustic signal amplitude, propagation speed, and shape by synchronizing the AW-mLIBS system with a high-speed camera. The results revealed that the laser-induced plasma-optical emission increases with increasing temperature and is unaffected by laser ablation angle up to 40 degree because the amount of the ablated mass was similar and the plasma. Additionally, no considerable variation in plasma temperature obtained using the Boltzmann method over the sample temperature. However, the propagation speed of the laser-induced plasma-acoustic signal differs with temperature but has marginal angular dependence because the laser-induced plasma-acoustic signal propagates as semispherical. Furthermore, small and no considerable changes observed in the laser-induced plasma-acoustic signal amplitude up to 100 degree Celsius, and the laser ablation angle showed a similar tendency to that of the laser-induced plasma-optical emission.

地質環境の長期安定性に関する研究 年度計画書(令和6年度)

丹羽 正和; 島田 顕臣; 浅森 浩一; 末岡 茂; 小松 哲也; 中嶋 徹; 小形 学; 内田 真緒; 西山 成哲; 田中 桐葉; et al.

JAEA-Review 2024-035, 29 Pages, 2024/09

JAEA-Review-2024-035.pdf:1.24MB

本計画書では、高レベル放射性廃棄物の地層処分技術に関する研究開発のうち、深地層の科学的研究の一環として実施している地質環境の長期安定性に関する研究について、第4期中長期目標期間(令和4年度令和10年度)における令和6年度の研究開発計画を取りまとめた。本計画の策定にあたっては、これまでの研究開発成果や大学等で行われている最新の研究成果に加え、地層処分事業実施主体や規制機関等の動向を考慮した。研究の実施にあたっては、地層処分事業における概要・精密調査や国の安全規制に対し研究成果を適時反映できるよう、(1)調査技術の開発・体系化、(2)長期予測・影響評価モデルの開発、(3)年代測定技術の開発の三つの枠組みで研究開発を推進する。

Application of diffusive gradients in thin films (DGT) for the dynamic speciation of radioactive cesium in Fukushima Prefecture, Japan

田中 琢朗*; 福岡 将史*; 戸田 賀奈子*; 中西 貴宏; 寺島 元基; 藤原 健壮; 庭野 佑真*; 加藤 弘亮*; 小林 奈通子*; 田野井 慶太朗*; et al.

ACS ES&T Water (Internet), 4(8), p.3579 - 3586, 2024/08

https://doi.org/10.1021/acsestwater.4c00453

Radioactive cesium released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011 remains in the forest environment and is being transported to the ocean via residential areas by runoff into river systems. Most of the Cs in river water exists as suspended forms, being strongly fixed by micaceous clay minerals. If this fraction can change its form into dissolved forms, this results in additional input of bioavailable Cs. In this study, in-situ sampling of Cs at multiple rivers in Fukushima Prefecture was conducted using the DGT (diffusive gradient in thin film) devices to investigate the dynamics of radioactive cesium in river environments. At almost all sampling points, the DGT Cs concentrations exceeded dissolved Cs concentrations, revealing the existence of a flux from the suspended to the dissolved forms. This additional input was found to have higher Cs/ Cs ratios, compared those of Cs in the dissolved form. This study demonstrates that the bioavailability of Cs can be underestimated by assessing only the dissolved form due to Cs flux from the suspended particles likely caused by their dissolution.

Analysis of particles containing alpha emitters in stagnant water in Fukushima Daiichi Nuclear Power Station's Unit 3 reactor building

蓬田 匠; 大内 和希; 森井 志織; 岡 壽崇; 北辻 章浩; 駒 義和; 今野 勝弘*

Scientific Reports (Internet), 14, p.14945_1 - 14945_11, 2024/06

https://doi.org/10.1038/s41598-024-65522-2

福島第一原子力発電所3号機建屋滞留水中の固形分の多数の粒子状物質の中から、核種を含有する微粒子の検出を試みた。核種濃度の異なる、トーラス室と主蒸気隔離弁室の2か所から採取した試料について分析を行った。大部分の核種は10m以上の固形分に存在していた。SEM-EDXを用いる元素分析により、mサイズのUを主成分とする微粒子を検出した。また、アルファトラック法により検出した粒子では、粒径100m程度までの鉄粒子上に核種が分布する様子を観測できた。3号機滞留水中におけるUやその他の核種の存在形態が明らかになった。