Fukuda, Tatsuya*; Takahashi, Ryo*; Hara, Takuhi*; Ohara, Koji*; Kato, Kazuo*; Matsumura, Daiju; Inaba, Yusuke*; Nakase, Masahiko*; Takeshita, Kenji*
Journal of Nuclear Science and Technology, 58(4), p.399 - 404, 2021/04
Saga, Ryo*; Matsuya, Yusuke; Takahashi, Rei*; Hasegawa, Kazuki*; Date, Hiroyuki*; Hosokawa, Yoichiro*
Scientific Reports (Internet), 11(1), p.8258_1 - 8258_10, 2021/04
Hyaluronan synthesis inhibitor 4-methylumbelliferone (4-MU) is a candidate of radiosensitizers in X-ray therapy. The curative effects under such 4-MU administration have been investigated in vitro; however, the radiosensitizing mechanisms remain unclear. Here, we investigated the radiosensitizing effects under 4-MU treatment from cell experiments and model estimations. We generated experimental surviving fractions of human fibrosarcoma cells (HT1080) after 4-MU treatment combined with X-ray irradiation. Meanwhilst, we also modelled the pharmacological effects of 4-MU treatment and theoretically analyzed the synergetic effects between 4-MU treatment and X-ray irradiation. The results show that the enhancement of cell killing by 4-MU treatment is the greatest in the intermediate dose range of around 4 Gy, which indicates the involvement of intercellular communication. In addition, the oxidative stress level, which leads to DNA damage induction, significantly increased under 4-MU treatment, and the radiosensitization by 4-MU can be suppressed by the inhibitors for intercellular communication. These findings suggest that the synergetic effects between 4-MU treatment and irradiation are predominantly attributed to intercellular communication and provide more efficient tumour control than conventional X-ray therapy.
Miao, P.*; Tan, Z.*; Lee, S. H.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Yonemura, Masao*; Koda, Akihiro*; Komatsu, Kazuki*; Machida, Shinichi*; Sano, Asami; et al.
Physical Review B, 103(9), p.094302_1 - 094302_18, 2021/03
The layered perovskite PrBaCoO demonstrates a strong negative thermal expansion (NTE) which holds potential for being fabricated into composites with zero thermal expansion. The NTE was found to be intimately associated with the spontaneous magnetic ordering, known as magneto-volume effect (MVE). Here we report with compelling evidences that the continuous-like MVE in PrBaCoO is intrinsically of discontinuous character, originating from an magnetoelectric transition from an antiferromagnetic insulating large-volume (AFILV) phase to a ferromagnetic less-insulating small-volume (FLISV) phase. Furthermore, the magnetoelectric effect (ME) shows high sensitivity to multiple external stimuli such as temperature, carrier doping, hydrostatic pressure, magnetic field etc. In contrast to the well-known ME such as colossal magnetoresistance and multi-ferroic effect which involve symmetry breaking of crystal structure, the ME in the cobaltite is purely isostructural. Our discovery provides a new path way to realizing the ME as well as the NTE, which may find applications in new techniques.
Komatsu, Kazuki*; Iwasaki, Tsugumi*; Murata, Kosuke*; Yamashiro, Hideaki*; Goh, V. S. T.*; Nakayama, Ryo*; Fujishima, Yohei*; Ono, Takumi*; Kino, Yasushi*; Shimizu, Yoshinaka*; et al.
Reproduction in Domestic Animals, 56(3), p.484 - 497, 2021/03
We have established an archive system of livestock and wild animals from the surrounding ex-evacuation zone. Wildlife within the alert zone have been exposed to low-dose-rate (LDR) radiation for a long and continuous time. In this study, we analysed the morphological characteristics of the testes and in vitro fertilization (IVF) capacity of cryopreserved sperm of raccoons from the ex-evacuation zone of the FDNPP accident. This study revealed that the chronic and LDR radiation exposure associated with the FDNPP accident had no adverse effect on the reproductive characteristics and functions of male raccoons.
Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.
Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12
The dry and wet depositions of atmospheric ammonia (NH) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.
Takahashi, Ryo*; Chudo, Hiroyuki; Matsuo, Mamoru; Harii, Kazuya*; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji
Nature Communications (Internet), 11, p.3009_1 - 3009_6, 2020/06
Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.
Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12
We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.
Saga, Ryo*; Matsuya, Yusuke; Takahashi, Rei*; Hasegawa, Kazuki*; Date, Hiroyuki*; Hosokawa, Yoichiro*
Journal of Radiation Research, 60(3), p.298 - 307, 2019/05
In radiotherapy, it is recognized that cancer stem cells (CSCs) in tumor tissue shows radio-resistance. However, the relationship between content percentage of the CSCs and dose-response curve on cell survival remain unclear. In this study, we developed a stochastic model considering progeny cells and stem cells, and investigated the impact of stem cells on radio-sensitivity. From the flow-cytometric analysis (cell experiments), the content percentage of stem cells was 3.2% or less which agreed well with the model estimation from the cell survival curve. Based on the verification, it is suggested that cell survival in high-dose range is largely affected by the CSCs. In addition, regarding the sub-population of stem cells, the present model well reproduces the dose response on lethal lesions to DNA comparing with the conventional LQ model. This outcome indicates that the stem cells must be considered for describing the dose-response curve in wide dose range.
Kajimoto, Ryoichi; Ishikado, Motoyuki*; Kira, Hiroshi*; Kaneko, Koji; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Murai, Naoki; et al.
Physica B; Condensed Matter, 556, p.26 - 30, 2019/03
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
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.
Takahashi, Nobuo; Suekane, Yurika; Sakaba, Ryosuke*; Kurosawa, Takuya*; Sato, Koichi; Meguro, Yoshihiro
JAEA-Testing 2018-002, 45 Pages, 2018/07
The Japan Atomic Energy Agency has many nuclear facilities such as research reactors, nuclear fuel facilities and research facilities. Although these facilities will be decommissioned due to the termination of the purpose of use of the facility and aging, it is necessary to evaluate the decommissioning cost of these facilities prior to the decommissioning. We have developed an evaluation method called DECOST code that can efficiently calculate the decommissioning cost in a short time based on factors such as features, similarity, and dismantling methods. This report is as a manual of the DECOST code prepared for improving convenience. Here, the evaluation formulae used for DECOST are presented and the method of using them is explained for each kind of nuclear facilities to be evaluated. In addition, the preparation method of facility information and dismantled waste amount that are need for evaluation is also shown.
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
Yasuda, Satoshi; Takahashi, Ryosuke*; Osaka, Ryo*; Kumagai, Ryota*; Miyata, Yasumitsu*; Okada, Susumu*; Hayamizu, Yuhei*; Murakoshi, kei*
Small, 13(31), p.1700748_1 - 1700748_8, 2017/08
MoS and MoSe monolayers are grown on Au surface by chemical vapor deposition and it is demonstrated that the contact with a crystalline Au(111) surface gives rise to only out-of-plane strain in both MoS and MoSe layers, whereas no strain generation is observed on polycrystalline Au or SiO/Si surfaces. Scanning tunneling microscopy analysis provides information regarding consequent specific adsorption sites between lower S (Se) atoms in the S-Mo-S (Se-Mo-Se) structure and Au atoms via unique moir superstructure formation for MoS and MoSe layers on Au(111). This observation indicates that the specific adsorption sites give rise to out-of-plane strain in the TMDC layers. Furthermore, it also leads to effective modulation of the electronic structure of the MoS or MoSe layer.
Watanabe, Shingo*; Hirobe, Daichi*; Shiomi, Yuki*; Iguchi, Ryo*; Daimon, Shunsuke*; Kameda, Mai*; Takahashi, Saburo*; Saito, Eiji
Scientific Reports (Internet), 7, p.4576_1 - 4576_6, 2017/07
Seo, Y.-J.*; Harii, Kazuya; Takahashi, Ryo*; Chudo, Hiroyuki; Oyanagi, Koichi*; Qiu, Z.*; Ono, Takahito*; Shiomi, Yuki*; Saito, Eiji
Applied Physics Letters, 110(13), p.132409_1 - 132409_4, 2017/03
We have fabricated ferrite cantilevers in which their vibrational properties can be controlled by external magnetic fields. Submicron-scale cantilever structures were made from YFeO films by physical etching combined with the use of a focused ion beam milling technique. We found that the cantilevers exhibit two resonance modes which correspond to horizontal and vertical vibrations. Under external magnetic fields, the resonance frequency of the horizontal mode increases, while that of the vertical mode decreases, quantitatively consistent with our numerical simulation for magnetic forces. The changes in resonance frequencies with magnetic fields reach a few percent, showing that an efficient magnetic control of resonance frequencies was achieved.
Tanimura, Yoshihiko; Tomita, Jumpei; Yoshitomi, Hiroshi; Yoshizawa, Michio; Hakozaki, Ryozo*; Takahashi, Sohei*
Hoken Butsuri, 51(3), p.141 - 146, 2016/09
Photon spectra were measured inside and outside a house in Minami-Soma city by using a NaI(Tl) scintillation spectrometer. The photons were categorized into three groups according to their energy. The groups were (1) scattered photons, which include low energy photons, (2) direct photons from Cs and Cs sources and (3) the other photons. Then the ratios of the ambient dose equivalents H(10) of the scattered photons to those of the direct photons from the Cs and Cs sources have been evaluated from the measured photon spectra. The ratios are high inside the house compared with those out of the house. It was found that the scattered photons contribute to the H(10) by more than 50 inside the house. The ambient dose equivalent average energies of the scattered photons are around 0.25 MeV both inside and outside the house. These data is worthwhile to design the optimum shielding for the protection against the public radiation exposure.
Oshima, Katsumi; Oda, Yasuhisa; Takahashi, Koji; Terakado, Masayuki; Ikeda, Ryosuke; Hayashi, Kazuo*; Moriyama, Shinichi; Kajiwara, Ken; Sakamoto, Keishi
JAEA-Technology 2015-061, 65 Pages, 2016/03
In JAEA, an ITER relevant control system for ITER gyrotron was developed according to Plant Control Design Handbook. This control system was developed based on ITER CODAC Core System and implemented state machine control of gyrotron operation system, sequential timing control of gyrotron oscillation startup, and data acquisition. The operation of ITER 170 GHz gyrotron was demonstrated with ITER relevant power supply configuration. This system is utilized for gyrotron operation test for ITER procurement. This report describes the architecture of gyrotron operation system, its basic and detailed design, and recent operation results.
Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.
Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02
Okumura, Yoshikazu; Gobin, R.*; Knaster, J.*; Heidinger, R.*; Ayala, J.-M.*; Bolzon, B.*; Cara, P.*; Chauvin, N.*; Chel, S.*; Gex, D.*; et al.
Review of Scientific Instruments, 87(2), p.02A739_1 - 02A739_3, 2016/02
IFMIF is an accelerator based neutron facility having two set of linear accelerators each producing 125mA/CW deuterium ion beams (250mA in total) at 40MeV. The LIPAc (Linear IFMIF Prototype Accelerator) being developed in the IFMIF-EVEDA project consists of an injector, a RFQ accelerator, and a part of superconducting Linac, whose target is to demonstrate 125mA/CW deuterium ion beam acceleration up to 9MeV. The injector has been developed in CEA Saclay and already demonstrated 140mA/100keV deuterium beam. The injector was disassembled and delivered to the International Fusion Energy Research Center (IFERC) in Rokkasho, Japan, and the commissioning has started after its reassembly 2014; the first beam production has been achieved in November 2014. Up to now, 100keV/120mA/CW hydrogen ion beam has been produced with a low beam emittance of 0.2 .mm.mrad (rms, normalized).
Shinto, Katsuhiro; Sene, F.*; Ayala, J.-M.*; Bolzon, B.*; Chauvin, N.*; Gobin, R.*; Ichimiya, Ryo; Ihara, Akira; Ikeda, Yukiharu; Kasugai, Atsushi; et al.
Review of Scientific Instruments, 87(2), p.02A727_1 - 02A727_3, 2016/02