Radiation exposure and oxidative stress status of wild Japanese macaques in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident

Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.

KEK Proceedings 2022-2, p.61 - 66, 2022/11

The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.

Dimensional reduction by geometrical frustration in a cubic antiferromagnet composed of tetrahedral clusters

Okuma, Ryutaro*; Kofu, Maiko; Asai, Shinichiro*; Avdeev, M.*; Koda, Akihiro*; Okabe, Hirotaka*; Hiraishi, Masatoshi*; Takeshita, Soshi*; Kojima, Kenji*; Kadono, Ryosuke*; et al.

Nature Communications (Internet), 12, p.4382_1 - 4382_7, 2021/07

https://doi.org/10.1038/s41467-021-24636-1

Bound spinon excitations in the spin- anisotropic triangular antiferromagnet CaReOCl

Nawa, Kazuhiro*; Hirai, Daigoro*; Kofu, Maiko; Nakajima, Kenji; Murasaki, Ryo*; Kogane, Satoshi*; Kimata, Motoi*; Nojiri, Hiroyuki*; Hiroi, Zenji*; Sato, Taku*

Physical Review Research (Internet), 2(4), p.043121_1 - 043121_11, 2020/12

https://doi.org/10.1103/PhysRevResearch.2.043121

The spin excitations of the = anisotropic triangular antiferromagnet CaReOCl were investigated by inelastic neutron-scattering experiments. The spin excitation spectrum exhibits sharp dispersive modes in addition to a spinonlike continuum. The consistency with the simulated spectrum based on the random-phase approximation is better for CaReOCl than for CsCuCl, indicating that the spin system in the former remains closer to a Tomonaga-Luttinger liquidlike disordered state.

Emergent spin-1 Haldane gap and ferroelectricity in a frustrated spin- ladder

Ueda, Hiroshi*; Onoda, Shigeki*; Yamaguchi, Yasuhiro*; Kimura, Tsuyoshi*; Yoshizawa, Daichi*; Morioka, Toshiaki*; Hagiwara, Masayuki*; Hagihara, Masato*; Soda, Minoru*; Masuda, Takatsugu*; et al.

Physical Review B, 101(14), p.140408_1 - 140408_6, 2020/04

https://doi.org/10.1103/PhysRevB.101.140408

Crystal structures of highly hole-doped layered perovskite nickelate PrSrNiO studied by neutron diffraction

Kajimoto, Ryoichi; Nakajima, Kenji; Fujita, Masaki*; Ishikado, Motoyuki*; Torii, Shuki*; Ishikawa, Yoshihisa*; Miao, P.*; Kamiyama, Takashi*

Journal of the Physical Society of Japan, 88(11), p.114602_1 - 114602_6, 2019/11

https://doi.org/10.7566/JPSJ.88.114602

Joint meeting of young researchers in the field of radiation protection and radiation biology

Kataoka, Noriaki*; Nakajima, Junya; Miwa, Kazuji; Hirota, Seiko*; Tsubota, Yoichi; Yamada, Ryohei; Fujimichi, Yuki*; Ishikawa, Junya*; Sunaoshi, Masaaki*

Hoken Butsuri (Internet), 54(2), p.140 - 145, 2019/06

https://doi.org/10.5453/jhps.54.140

It is the written report of the joint meeting of young researchers in the field of radiation protection and radiation biology.

Presentation Materials Related to Neutron Instruments in the Technical Study Meetings for Future MLF

Nakajima, Kenji; Harjo, S.; Yamada, Norifumi*; Oikawa, Kenichi; Kajimoto, Ryoichi

JAEA-Review 2018-032, 43 Pages, 2019/02

JAEA-Review-2018-032.pdf:9.78MB

A series of meetings to discuss future neutron/muon sources and instruments at Materials and Life Science Experimental Facility (MLF) in Japan Proton Accelerator Research Complex (J-PARC) has been held since 2017. Each of the neutron instrument groups in MLF proposed required features for future instruments, while addressing issues of the current instruments and facilities. This report compiles the presentation materials presented by the neutron instrument groups in the meetings to help future discussion for the coming MLF.

Anomaly of structural relaxation in complex liquid metal of bismuth; Dynamic correlation function of coherent quasi-elastic neutron scattering

Kawakita, Yukinobu; Kikuchi, Tatsuya*; Inamura, Yasuhiro; Tahara, Shuta*; Maruyama, Kenji*; Hanashima, Takayasu*; Nakamura, Mitsutaka; Kiyanagi, Ryoji; Yamauchi, Yasuhiro*; Chiba, Kaori*; et al.

Physica B; Condensed Matter, 551, p.291 - 296, 2018/12

https://doi.org/10.1016/j.physb.2017.12.037

There are elemental liquid metals with complex structures far from the hard sphere (HS) packing model. Liquid Bi has an asymmetric first peak in the structure factors S(Q). The pair distribution function g(r) exhibits strange distance ratio of 1:2 between the first and the second peaks. Since a HS model with two kinds of radius produces asymmetry of the main peak in S(Q), existence of short-lived covalent bonds was discussed. Contrarily, modulation of the atomic distribution by the Friedel oscillations of shielding electrons around metallic ions was discussed. To examine its bonding nature from viewpoints of dynamic correlation functions, we have measured neutron quasielastic scattering of liquid Bi by using cold disk chopper spectrometer installed at MLF of J-PARC. The van Hove function revealed that the shoulder structure located at a longer side of the first peak in g(r) exhibits a longer relaxation time than the main structures such as the first and second peaks.

Status report of the chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Murai, Naoki; Kira, Hiroshi*; Nakatani, Takeshi; et al.

Journal of Physics; Conference Series, 1021(1), p.012030_1 - 012030_6, 2018/06

BB2016-1727.pdf:0.39MB

https://doi.org/10.1088/1742-6596/1021/1/012030

Detailed study of the structure of the low-energy magnetic excitations in overdoped LaSrCuO

Ikeuchi, Kazuhiko*; Kikuchi, Tatsuya*; Nakajima, Kenji; Kajimoto, Ryoichi; Wakimoto, Shuichi; Fujita, Masaki*

Physica B; Condensed Matter, 536, p.717 - 719, 2018/05

https://doi.org/10.1016/j.physb.2017.11.022

To examine the detailed structure of low-energy magnetic excitations in a high-transition-temperature superconducting cuprate with heavily hole-doping, we performed inelastic neutron scattering experiments on LaSrCuO. We observed clear dispersion relations of the previously reported incommensurate (IC) magnetic correlations at = (0.5 , 0.5)/(0.5, 0.5 ). In addition, we show the emergence of continuum magnetic excitations with a ring shape centered at point in a constant energy spectrum at = 50 K. The radius of the ring ( = 0.109) is smaller than the incommensurability ( = 0.118). This suggests that the origin of the ring-like excitations is different from that of the IC magnetic correlations, and the low-energy magnetic excitations of the LaSrCuO system are inherently composed of these two kinds of excitations.