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Journal Articles

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields

Matsuya, Yusuke; Nakano, Toshiaki*; Kai, Takeshi; Shikazono, Naoya*; Akamatsu, Ken*; Yoshii, Yuji*; Sato, Tatsuhiko

International Journal of Molecular Sciences (Internet), 21(5), p.1701_1 - 1701_13, 2020/03

 Times Cited Count:4 Percentile:65.16(Biochemistry & Molecular Biology)

Among various DNA damage induced after irradiation, clustered damage composed of at least two vicinal lesions within from 10 to 20 base pairs is recognized as fatal damage to human tissue. Such clustered damage yields have been evaluated by means of computational approaches; however, the simulation validity has not been sufficiently made yet. Meanwhile, the experimental technique to detect clustered DNA damage has been evolved in the recent decades, so both approaches with simulation and experiment get used to be available for investigating clustered damage recently. In this study, we have developed a simple model for estimating clustered damage yield based on the spatial density of ionization and electronic excitation events obtained by the PHITS code, and compared the computational results to the experimental clustered damage coupled with base damage (BD) measured by gel electrophoresis and atomic force microscopy. The computational results agreed well with experimental fractions of clustered damage of strand breaks (SB) and BD, when the yield ratio of BD/SSB is assumed to be 1.3. From the comparison of complex DNA double-strand break coupled with BDs between simulation and experimental data, it was suggested that aggregation degree of the events along electron track reflects the complexity of DNA damage. The resent simulation enables to quantify the type of clustered damage which cannot be measured in in vitro experiment, which succeeded in interpreting the experimental detection efficiency for clustered BD.

Journal Articles

Weak-coupling mean-field theory of magnetic properties of NiGa$$_{2}$$S$$_{4}$$

Nomura, Takuji*; Yamamoto, Yuji*; Yoshii, Kenji

Journal of the Physical Society of Japan, 89(2), p.024704_1 - 024704_10, 2020/02

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

We report a mean-field theoretical study of a triangular magnet NiGa$$_{2}$$S$$_{4}$$. Using the localized Wannier functions obtained from a band calculation, the most stable magnetic state was found to be spiral with the incommensurate structure, consistent with the result from neutron diffraction. The Ni-site Coulomb interaction was not strong (U about 2 eV). The spin value at the Ni site was also not so large about 1.1 mb. These results mean that the hybridization between Ni and S may play an important role. The dynamical spin correlation function was found to in accord with the results from neutron scattering.

Journal Articles

Track structure study for energy dependency of electrons and X-rays on DNA double-strand break induction

Yachi, Yoshie*; Yoshii, Yuji*; Matsuya, Yusuke; Mori, Ryosuke*; Oikawa, Joma*; Date, Hiroyuki*

Scientific Reports (Internet), 9(1), p.17649_1 - 17649_8, 2019/11

 Times Cited Count:1 Percentile:15.41(Multidisciplinary Sciences)

Radiation weighting factor for photon and electron is defined as 1.0 independently these energies. However, it should be noted that the biological effects after 29 kVp X-rays is relative higher than standard 200 kVp X-rays at the endpoint of ${it in vitro}$. And it is of importance to evaluate electrons generated via interaction of photons with matter. Here, we evaluated the energy concentration along electron track (dose-mean lineal energy) on chromosome (micron-meter) scales by Monte Carlo simulation, and measured the DNA double-strand breaks (DSBs) induction. From the cell experiments, the DSBs induction after diagnostic X-rays exposure (60-100 kVp) is higher than those with therapeutic X-rays (6 MV). In the relation between the dose-mean lineal energy and the number of DSBs, it was shown that lower energy photons might induce more biological impact due to the interaction by low energy electron. This study implies that radiation weighting factor for photon and electron should not be unity.

Journal Articles

Modeling of yield estimation for DNA strand breaks based on Monte Carlo simulations of electron track structure in liquid water

Matsuya, Yusuke; Kai, Takeshi; Yoshii, Yuji*; Yachi, Yoshie*; Naijo, Shingo*; Date, Hiroyuki*; Sato, Tatsuhiko

Journal of Applied Physics, 126(12), p.124701_1 - 124701_8, 2019/09

 Times Cited Count:10 Percentile:74.82(Physics, Applied)

Biological effects after ionizing radiation exposure arise from initial DNA strand breaks. DNA damage can be estimated from the simulation with both track structure analysis and diffusion of free radicals; however, the simulation is a time-consuming process. In this study, we present a simple model for estimating yields of strand breaks based only on spatial patterns of inelastic interactions (i.e., ionization and electronic excitation) generated by electrons, which are evaluated by PHITS code without considering the production and diffusion of free radicals. In this model, the number of events per track and that of the two events pair within 3.4 nm (corresponding to 10 base pair) were stochastically sampled for calculating SSB and DSB yields, respectively. The calculated results agreed well with other simulations and experimental data on DSB yield and yield ratio of DSB/SSB for the exposure to mono-energetic electrons. The present model also can demonstrate the relative biological effectiveness at the DSB endpoint for various photon exposures. This study indicated that the spatial pattern of inelastic events composed of ionization and electronic excitation is sufficient to obtain the impact of electrons on initial induction to DNA strand break.

Journal Articles

Intensity modulated radiation fields induce protective effects and reduce importance of dose-rate effects

Matsuya, Yusuke; McMahon, S. J.*; Ghita, M.*; Yoshii, Yuji*; Sato, Tatsuhiko; Date, Hiroyuki*; Prise, K. M.*

Scientific Reports (Internet), 9(1), p.9483_1 - 9483_12, 2019/07

 Times Cited Count:6 Percentile:65.54(Multidisciplinary Sciences)

In radiotherapy, intensity modulated radiation fields and complex dose-delivery are used to prescribe doses to tumors. Here, we analyzed the impact of modulated field on radio-sensitivity and cell recovery during irradiation time. The dose was delivered to either 50% of the area of the flask containing cells (half-field) or 100% of the flask (uniform-field). We also modelled cell-killing considering dose-rate effects and intercellular signals. It is found that (i) in-field cell survival under half-field exposure is higher than uniform-field exposure even with the same dose; (ii) the importance of sub-lethal damage repair in normal human skin fibroblast cells under the half-field is reduced; (iii) the increase of cell survival under half-field is predominantly attributed to not rescue effects (increased repair) but protective effects (reduced initial DNA lesion yield). These findings provide new understanding of radio-sensitivity for hit and non-hit cells under non-uniform exposure.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2017

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yamada, Ryohei; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; et al.

JAEA-Review 2018-028, 120 Pages, 2019/02

JAEA-Review-2018-028.pdf:2.69MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and by law of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2017. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2016

Nakano, Masanao; Fujita, Hiroki; Nagaoka, Mika; Inoue, Kazumi; Koike, Yuko; Yoshii, Hideki*; Hiyama, Yoshinori*; Otani, Kazunori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2017-037, 119 Pages, 2018/03

JAEA-Review-2017-037.pdf:2.58MB

Based on the regulations (the safety regulation of Tokai Reprocessing Plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki Prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2016. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2015

Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Nagaoka, Mika; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2017-001, 115 Pages, 2017/03

JAEA-Review-2017-001.pdf:3.57MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2015. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Current status of research and development at Japan Atomic Energy Agency

Fujita, Yuji; Yoshii, Kenji

Denki Hyoron, 101(2), p.43 - 58, 2016/02

Japan Atomic Energy Agency (JAEA) is conducting many kinds of research activities, including fundamental and applied researches, and project studies to create novel technologies and industries. In particular, the activities are mainly focused on the R&D studies for recovery from the Fukushima Daiichi Nuclear NPS accident, safety researches, the development of fast reactor cycles, and high-level radioactive waste disposal. This article gives reviews on current status of the researches of JAEA in this fiscal year.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2015-030, 115 Pages, 2015/12

JAEA-Review-2015-030.pdf:25.28MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Present status of J-PARC linac

Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10

no abstracts in English

Journal Articles

Current-induced enhancement of magnetic anisotropy in spin-charge-coupled multiferroic YbFe$$_{2}$$O$$_{4}$$

Yoshii, Kenji; Matsumura, Daiju; Saito, Hiroyuki; Kambe, Takashi*; Fukunaga, Mamoru*; Muraoka, Yuji*; Ikeda, Naoshi*; Mori, Shigeo*

Journal of the Physical Society of Japan, 83(6), p.063708_1 - 063708_4, 2014/06

 Times Cited Count:4 Percentile:38.77(Physics, Multidisciplinary)

We report the change of magnetic properties of multiferroic YbFe$$_{2}$$O$$_{4}$$, caused by cooling in the presence of an electrical current. The magnetization measured after the cooling becomes smaller by about 10-20% than that after cooling without a current. The current also affects the magnetic anisotropy below about 100 K; the magnetic coercivity is increased by about 10-20%. These phenomena may arise from a coexistence of ferromagnetic and antiferromagnetic domains, or a disturbance in the formation of charge-ordered domains. From the applied viewpoint, the enhancement of anisotropy by an electrical current offers a method for stabilizing magnetization other than the well-known method, i.e., exchange bias.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2012

Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2013-041, 115 Pages, 2014/01

JAEA-Review-2013-041.pdf:19.01MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2009

Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Fujita, Hiroki; Isozaki, Tokuju; Morisawa, Masato; Mizutani, Tomoko; Kokubun, Yuji; et al.

JAEA-Review 2011-004, 161 Pages, 2011/03

JAEA-Review-2011-004.pdf:4.09MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2009 to March 2010. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2008

Takeishi, Minoru; Sumiya, Shuichi; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki*; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; et al.

JAEA-Review 2009-048, 177 Pages, 2009/12

JAEA-Review-2009-048.pdf:19.3MB
JAEA-Review-2009-048(errata).pdf:0.12MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2008 to March 2009. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2007

Takeishi, Minoru; Matsuura, Kenichi; Watanabe, Hitoshi; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; et al.

JAEA-Review 2008-057, 155 Pages, 2008/11

JAEA-Review-2008-057.pdf:2.15MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter IV; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2007 to March 2008. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

Journal Articles

Effects of oxygen annealing on dielectric properties of LuFeCuO$$_{4}$$

Matsuo, Yoji*; Suzuki, Muneyasu*; Noguchi, Yuji*; Yoshimura, Takeshi*; Fujimura, Norifumi*; Yoshii, Kenji; Ikeda, Naoshi*; Mori, Shigeo*

Japanese Journal of Applied Physics, 47(11), p.8464 - 8467, 2008/11

 Times Cited Count:10 Percentile:41.53(Physics, Applied)

We have investigated the physical properties of LuFeCuO$$_{4}$$, which is a derivative material of the electronic ferroelectric LuFe$$_{2}$$O$$_{4}$$. From electron diffraction measurements at room temperature, ionic ordering of Fe$$^{3+}$$ and Cu$$^{2+}$$ in the a-b plane was observed. This ordering is similar to that in LuFe$$_{2}$$O$$_{4}$$ and has an electric dipole. The observation of small domains (5-10 nm) indicates the presence of polar regions. Dielectric measurements showed that a peak of dielectric constant appeared at around 500 K, and the peak value was about 1000, indicating that LuFeCuO$$_{4}$$ is a dielectric material. We will present the experimental data on the samples prepared under high-pressure oxygen.

Journal Articles

X-ray magnetic circular dichroism and photoemission studies of ferromagnetism in CaMn$$_{1-x}$$Ru$$_{x}$$O$$_{3}$$ thin films

Terai, Kota*; Yoshii, Kenji; Takeda, Yukiharu; Fujimori, Shinichi; Saito, Yuji; Owada, Kenji; Inami, Toshiya; Okane, Tetsuo; Arita, Masashi*; Shimada, Kenya*; et al.

Physical Review B, 77(11), p.115128_1 - 115128_6, 2008/03

 Times Cited Count:12 Percentile:50.42(Materials Science, Multidisciplinary)

Journal Articles

Microstructures related to the ferroelectric properties in BiFeO$$_{3}$$-BaTiO$$_{3}$$

Kitagawa, Shuji*; Horibe, Yoichi*; Yoshii, Kenji; Suzuki, Muneyasu*; Noguchi, Yuji*; Nishihara, Sadafumi*; Hosokoshi, Yuko*; Mori, Shigeo*

Transactions of the Materials Research Society of Japan, 33(1), p.27 - 30, 2008/03

Microstructures related to the ferroelectric (FE) properties in(1-x)BiFeO$$_{3}$$-xBaTiO$$_{3}$$ were examined mainly by a transmission electron microscopy, in combination with conventional magnetic and dielectric measurements. It was found that macroscopic-sized FE domain structures in BiFeO$$_{3}$$changed into fine FE microstructures with the 20-30nm size in the x=0.25compound, as the BaTiO$$_{3}$$ concentration (x) was increased. In addition, we found characteristic tweed-like contrast due to the strain field in the x=0.33 compound at room temperature. We carefully investigated the spatial distribution of the FE microdomains in the x=0.25 compound by obtaining real-space images and determined spatial configuration of the spontaneous polarization in each FE microdomains.

JAEA Reports

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2006

Takeishi, Minoru; Miyagawa, Naoto; Nakano, Masanao; Takeyasu, Masanori; Isozaki, Hisaaki; Isozaki, Tokuju; Morisawa, Masato; Fujita, Hiroki; Kokubun, Yuji; Kato, Chiaki; et al.

JAEA-Review 2007-044, 155 Pages, 2008/02

JAEA-Review-2007-044.pdf:2.58MB
JAEA-Review-2007-044(errata).pdf:0.13MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of JAEA, Chapter 4; Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged to the atmosphere and the sea during April 2006 to March 2007. Appendices present comprehensive information, such as monitoring program, monitoring methods, monitoring results and its trends, meteorological data and discharged radioactive wastes.

66 (Records 1-20 displayed on this page)