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Yogo, Akifumi*; Lan, Z.*; Arikawa, Yasunobu*; Abe, Yuki*; Mirfayzi, S. R.*; Wei, T.*; Mori, Takato*; Golovin, D.*; Hayakawa, Takehito*; Iwata, Natsumi*; et al.
Physical Review X, 13(1), p.011011_1 - 011011_12, 2023/01
Times Cited Count：34 Percentile：96.84(Physics, Multidisciplinary)Kumazoe, Hiroyuki*; Igarashi, Yasuhiko*; Iesari, F.*; Shimizu, Ryota*; Komatsu, Yuya*; Hitosugi, Taro*; Matsumura, Daiju; Saito, Hiroyuki*; Iwamitsu, Kazunori*; Okajima, Toshihiko*; et al.
AIP Advances (Internet), 11(12), p.125013_1 - 125013_5, 2021/12
Times Cited Count：4 Percentile：20.44(Nanoscience & Nanotechnology)Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.
Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00
no abstracts in English
Saito, Katsuyo*; Funayama, Tomoo; Kobayashi, Yasuhiko; Murakami, Takashi*
JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 83, 2015/03
Epigenetic modifiers, such as histone deacetylase inhibitors (HDACi) and DNA methyltransferase inhibitors, have emerged recently as promising anticancer agents and it has been expected that epigenetic modifiers may enhance the effect of other cancer therapeutics including radiotherapy. Therefore, we investigated whether the use of epigenetic modifiers could sensitize melanoma cells for the heavy-ion therapy. Murine B16F10 melanoma cells were treated with investigational or comparator epigenetic modifier, then exposed to carbon ions of JAEA-Takasaki. After irradiation, the viabilities of cells were evaluated by colony formation assay. Treatment of B16F10 melanoma cells with HDACi trichostatin A (TSA) in combination with heavy-ion radiation provided enhanced inhibition of colony formation. The data suggest that combination of an epigenetic modifier TSA together with heavy-ion therapy may provide improved therapeutic responses in melanoma patients.
Sakashita, Tetsuya; Hamada, Nobuyuki*; Kawaguchi, Isao*; Hara, Takamitsu*; Kobayashi, Yasuhiko; Saito, Kimiaki
Journal of Radiation Research, 55(3), p.423 - 431, 2014/02
Times Cited Count：3 Percentile：15.91(Biology)Our previous analysis with a branching process model showed that the relative cell death (RCD) in human fibroblasts can persist over 16 generations following irradiation with low linear energy transfer (LET) 
-rays. Here we further set out to evaluate the RCD persistency in abortive colonies arising from normal human fibroblasts exposed to high-LET carbon ions (18.3 MeV/u, 108 keV/
m). We found that the abortive colony size distribution determined by biological experiments follows the linear relationship on the log-log plot, and that the Monte Carlo simulation using the RCD probability estimated from such linear relationship well simulates the experimentally determined surviving fraction and the relative biological effectiveness (RBE). We identified the short-term phase and long-term phase for the persistent RCD, as was the case for -irradiation.
Sakashita, Tetsuya; Hamada, Nobuyuki*; Kawaguchi, Isao*; Ouchi, Noriyuki; Hara, Takamitsu*; Kobayashi, Yasuhiko; Saito, Kimiaki
PLOS ONE (Internet), 8(7), p.e70291_1 - e70291_10, 2013/07
Times Cited Count：8 Percentile：34.23(Multidisciplinary Sciences)Clonogenicity gives important information about the cellular reproductive potential following ionizing irradiation. We firstly plotted the experimentally determined colony size distribution of abortive colonies in irradiated normal human fibroblasts, and found the linear relationship on the log-log plot. By applying the simple model of branching processes to the linear relationship, we found the persistent reproductive cell death (RCD) over several generations following irradiation. To verify the estimated probability of RCD, abortive colony size distribution (
15 cells/colony) and the surviving fraction were simulated by the Monte Carlo computational approach. Radiation-induced RCD (i.e. excess probability) lasted over 16 generations and mainly consisted of two components in the early and late phases. We found that short-term RCD is critical to the abortive colony size distribution, and long-lasting RDC is important for the dose response of the surviving fraction.
Watanabe, Ritsuko; Wada, Seiichi*; Funayama, Tomoo; Kobayashi, Yasuhiko; Saito, Kimiaki; Furusawa, Yoshiya*
Radiation Protection Dosimetry, 143(2-4), p.186 - 190, 2011/02
Times Cited Count：17 Percentile：76.48(Environmental Sciences)Microscopic energy deposition pattern in an ion track is thought to affect on the spatial distribution of DNA damage as well as the damage spectrum. In this study, we focus on the intra-track spatial distribution of DNA damage in cellular condition based on the energy deposition pattern for each ion obtained by the detailed Monte Carlo track structure simulation. The estimation was performed for C and Ne ions with similar LET around 440 keV/m. As a result, radial DNA damage distribution shows different pattern for C and Ne ions. That is, DSBs or non-DSB type clustered damage are formed in the limited central area while the isolated damages as SSBs and base lesions are spread in larger area. Such tendency is more clearly shown for Ne ions than C ions. This result shows good agreement with the previously obtained experimental observation at TIARA, which indicates the different types of DNA damage shows different distribution pattern around C and Ne projectiles in cell nuclei.
Tochio, Daisuke; Hamamoto, Shimpei; Inoi, Hiroyuki; Shimazaki, Yosuke; Sekita, Kenji; Kondo, Masaaki; Saikusa, Akio; Kameyama, Yasuhiko; Saito, Kenji; Emori, Koichi; et al.
JAEA-Technology 2010-038, 57 Pages, 2010/12
JAEA-Technology-2010-038.pdf:2.36MB
In HTTR, in-service operation is conducted through the rise-to power operation with rated operation or high-temperature test operation from achievement of first criticality at 1998. To make practical use HTGR system, it must be demonstrated to supply stable heat to heat utilization system for long-term. In HTTR, high-temperature/parallel-loaded long-term operation had been performed from January 2010. As the result, it was demonstrated to supply stable heat to heat utilization system for 50 days with HTTR, moreover, various long-term operation data were gained. This paper reports the characteristics of the high-temperature long-term operation for HTTR obtained from the operation.
Kameya, Hiromi*; Saito, Kimie*; Kikuchi, Masahiro; Kobayashi, Yasuhiko; Ukai, Mitsuko*; Todoriki, Setsuko*
Nihon Shokuhin Kagaku Kogakkai-Shi, 57(11), p.472 - 478, 2010/11
Times Cited Count：1 Percentile：7.38(Food Science & Technology)The detection methods of ray irradiated garlic blub were studied using electron spin resonance (ESR) spectroscopy, photo stimulated luminescence (PSL) and thermo luminescence (TL). The radiation source was 
Co, the dose level was 50 to 180 Gy. The ESR spectra were consisted of one singlet signal at 
= 2.00. Upon irradiation, the intensity of the singlet signal was increased. The intensity of PSL signals from stem of irradiated garlic blub was increased as compared with that from non irradiated ones. In TL measurement the glow 1 curves of irradiated samples exhibited a maximum at temperature range of 180 to 220
C, whereas those of the non irradiated samples were observed at about 300C. TL glow ratios calculated over the temperature range of 150 to 250C were significantly smaller in non irradiated samples than in irradiated samples after one year storage. Thus irradiated garlic blub was identified by the shape of TL glow 1 curves and TL glow ratios. We concluded ESR, PSL and TL are suitable for detection method of irradiated garlic blub.
-raysKobayashi, Yasuhiko; Kikuchi, Masahiro; Todoriki, Setsuko*; Saito, Kimie*; Katsura, Yoko*; Kameya, Hiromi*; Ichikawa, Mariko*; Iizuka, Tomoko*; Chiba, Etsuko*; Ukai, Mitsuko*
Shokuhin Shosha, 45(1-2), p.26 - 33, 2010/09
Effect of -irradiation on sprouting and rooting of garlic was investigated. Sprouting and rooting of garlic were inhibited by irradiation of bulbs at 2 months after harvest with doses more than 30 Gy. Four weeks-later irradiation requires higher doses to complete sprouting/rooting inhibition.
Ida, Katsumi*; Sakamoto, Yoshiteru; Yoshinuma, Mikiro*; Takenaga, Hidenobu; Nagaoka, Kenichi*; Hayashi, Nobuhiko; Oyama, Naoyuki; Osakabe, Masaki*; Yokoyama, Masayuki*; Funaba, Hisamichi*; et al.
Nuclear Fusion, 49(9), p.095024_1 - 095024_9, 2009/09
Times Cited Count：32 Percentile：72.57(Physics, Fluids & Plasmas)Dynamics of ion internal transport barrier (ITB) formation and impurity transport both in the Large Helical Device (LHD) heliotron and JT-60U tokamak are described. Significant differences between heliotron and tokamak plasmas are observed. The location of the ITB moves outward during the ITB formation regardless of the sign of magnetic shear in JT-60U and the ITB becomes more localized in the plasma with negative magnetic shear. In LHD, the low Te/Ti ratio (
1) of the target plasma for the high power heating is found to be necessary condition to achieve the ITB plasma and the ITB location tends to expand outward or inward depending on the condition of the target plasmas. Associated with the formation of ITB, the carbon density tends to be peaked due to inward convection in JT-60U, while the carbon density becomes hollow due to outward convection in LHD. The outward convection observed in LHD contradicts the prediction by neoclassical theory.
Tochio, Daisuke; Nojiri, Naoki; Hamamoto, Shimpei; Inoi, Hiroyuki; Sekita, Kenji; Kondo, Masaaki; Saikusa, Akio; Kameyama, Yasuhiko; Saito, Kenji; Fujimoto, Nozomu
JAEA-Technology 2009-005, 47 Pages, 2009/05
JAEA-Technology-2009-005.pdf:4.01MB
HTTR is now conducted in-service operation through the rise-to power operation with rated operation or high-temperature test operation from achievement of first criticality at 1998. In order to demonstrate to supply stable heat to heat utilization system for long-term, HTTR was conducted rated/parallel-loaded 30-days operation. This paper reports the characteristics of long-term operation for HTTR.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Muto, Takashi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Nuclear Fusion, 47(10), p.S668 - S676, 2007/10
Times Cited Count：35 Percentile：72.48(Physics, Fluids & Plasmas)The performance of net-current free heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fuelling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an internal diffusion barrier (IDB) by a combination of efficient pumping of the local island divertor function and core fuelling by pellet injection has realized a super dense core as high as 5
10
m
, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5% and a discharge duration of 54 min with a total input energy of 1.6 GJ (490 kW on average) are also highlighted. The progress of LHD experiments in these two years is overviewed by highlighting IDB, high-beta and long pulse.
Kakizaki, Takehiko; Hamada, Nobuyuki*; Sakashita, Tetsuya; Wada, Seiichi*; Hara, Takamitsu*; Funayama, Tomoo; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Kobayashi, Yasuhiko; et al.
Journal of Veterinary Medical Science, 69(6), p.605 - 609, 2007/06
Times Cited Count：1 Percentile：13.33(Veterinary Sciences)no abstracts in English
Saito, Hiroshi; Takahashi, Kuniaki; Miyasaka, Yasuhiko*; Yamana, Hajimu*
Dekomisshoningu Giho, (35), p.35 - 44, 2007/03
The WISMUT GmbH has carried out environmental remediation activities since 1991 in former GDR (German Democratic Republic) to rehabilitate the environment and landscape which have been adversely affected by decades of unrestrained mining and processing of uranium ores. It is worthy of being mentioned especially that WISMUT GmbH's sites including waste rock dump, mill tailings pond, open pit mine and water treatment facilities with an area of 3,700ha have been rehabilitated practically and extensively, and these activities are planned to terminate in 2015 except for the water treatment. For safety assessment after remediation, 1mSv/y (in excess of the background level) is applied to as an individual effective dose, from the recommendation of ICRP (International Commission on Radiological Protection). This report shows a summary of environmental remediation activities carried out by the WISMUT GmbH and related regulatory laws.
Motojima, Osamu*; Yamada, Hiroshi*; Komori, Akio*; Oyabu, Nobuyoshi*; Kaneko, Osamu*; Kawahata, Kazuo*; Mito, Toshiyuki*; Muto, Takashi*; Ida, Katsumi*; Imagawa, Shinsaku*; et al.
Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 12 Pages, 2007/03
The performance of net-current free Heliotron plasmas has been developed by findings of innovative operational scenarios in conjunction with an upgrade of the heating power and the pumping/fueling capability in the Large Helical Device (LHD). Consequently, the operational regime has been extended, in particular, with regard to high density, long pulse length and high beta. Diversified studies in LHD have elucidated the advantages of net-current free heliotron plasmas. In particular, an Internal Diffusion Barrier (IDB) by combination of efficient pumping of the local island divertor function and core fueling by pellet injection has realized a super dense core as high as 510m, which stimulates an attractive super dense core reactor. Achievements of a volume averaged beta of 4.5 % and a discharge duration of 54-min. with a total input energy of 1.6 GJ (490 kW in average) are also highlighted. The progress of LHD experiments in these two years is overviewed with highlighting IDB, high 
and long pulse.
Ito, Kotaro*; Takeichi, Junya*; Hanya, Yoshiki*; Sato, Katsuya; Hase, Yoshihiro; Sakashita, Tetsuya; Kobayashi, Yasuhiko; Narumi, Issei
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 98, 2007/02
no abstracts in English
Higashitani, Atsushi*; Sugimoto, Tomoko*; Mori, Chihiro*; Suzuki, Yoko*; Saito, Rumiko*; Ichishi, Eiichiro*; Sakashita, Tetsuya; Hamada, Nobuyuki*; Wada, Seiichi*; Kakizaki, Takehiko; et al.
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 113, 2007/02
no abstracts in English
Sano, Tadashi*; Wada, Seiichi*; Suzuki, Keiko*; Natsuhori, Masahiro*; Kakizaki, Takehiko; Ito, Takashi*; Nakazawa, Konomi*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 115, 2007/02
-rays and energetic carbon ionsKakizaki, Takehiko; Hamada, Nobuyuki*; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi*; Hodatsu, Tsutomu*; Natsuhori, Masahiro*; Sano, Tadashi*; Kobayashi, Yasuhiko; Ito, Nobuhiko*
Journal of Veterinary Medical Science, 68(12), p.1269 - 1273, 2006/12
Times Cited Count：3 Percentile：22.71(Veterinary Sciences)no abstracts in English
