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Noguchi, Miho; Kanari, Yukiko; Yokoya, Akinari; Narita, Ayumi; Fujii, Kentaro
Radiation Protection Dosimetry, 166(1-4), p.101 - 103, 2015/09
Times Cited Count:1 Percentile:9.79(Environmental Sciences)Narita, Ayumi; Kaminaga, Kiichi; Yokoya, Akinari; Noguchi, Miho; Kobayashi, Katsumi*; Usami, Noriko*; Fujii, Kentaro
Radiation Protection Dosimetry, 166(1-4), p.192 - 196, 2015/09
Times Cited Count:3 Percentile:26.04(Environmental Sciences)For the knowledge about irradiation effects of mammalian cells depending on the cell cycle, most of them had been analyzed by statistical approches. Our purpose is to establish the method for real-time observation of irradiated cells under a microscope. Fluorescent ubiquitination-based cell cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were selectively irradiated according to cell color observed in the same microscopic field in a culture dish. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. The cell cycle was strongly arrested by irradiation at S/G2 and never progressed to G1. In contrast, cells irradiated at G1 progress to S/G2 with a similar time course as non-irradiated control cells. These results show single FUCCI cell exposure and live cell imaging are powerful methods for studying radiation effects on the cell cycle.
Yokoya, Akinari; Shikazono, Naoya; Fujii, Kentaro; Noguchi, Miho; Urushibara, Ayumi
Radiation Protection Dosimetry, 143(2-4), p.219 - 225, 2011/02
Times Cited Count:3 Percentile:26.09(Environmental Sciences)Multiple single-strand breaks (m-SSBs), which are predicted to be preferentially induced by high LET radiation, would be underestimated if one uses the conventional method using plasmid DNA, because m-SSBs will not cause additionally conformational changes if they are on the same or on the opposite strand but separated each other sufficiently so as not to induce a double strand break. In order to observe the invisible m-SSBs, we have developed a novel technique using DNA denaturation. The m-SSBs arising in both strands of DNA are revealed as molecular size change in single strand DNA (SS-DNA) by gel electrophoresis. We have applied this method to the X- and He ion irradiated sample of hydrated pUC18 plasmid DNA. A half of SS-DNA population remains as intact within the experimental resolution ( 140 bases) for both irradiations. Contrary to our initial expectation, these results indicate that SSBs are not multiply induced over 140 bp even by high-LET irradiation.
Shikazono, Naoya; Yokoya, Akinari; Urushibara, Ayumi; Noguchi, Miho; Fujii, Kentaro
Radiation Protection Dosimetry, 143(2-4), p.181 - 185, 2011/02
Times Cited Count:2 Percentile:18.37(Environmental Sciences)Shikazono, Naoya; Noguchi, Miho; Fujii, Kentaro; Urushibara, Ayumi*; Yokoya, Akinari
Journal of Radiation Research, 50(1), p.27 - 36, 2009/01
Times Cited Count:112 Percentile:88.08(Biology)After living cells are exposed to ionizing radiation, a variety of chemical modifications of DNA are induced either directly by ionization of DNA or indirectly through interactions with water-derived radicals. Clustered DNA damage, which is defined as two or more of such lesions within one to two helical turns of DNA induced by a single radiation track, is considered to be a unique feature of ionizing radiation. A double strand break (DSB) is a type of clustered DNA damage. Formation and repair of DSBs have been studied in great detail over the years as they have been linked to important biological endpoints. Although non-DSB clustered DNA damage has received less attention, there is growing evidence of its biological significance. This review focuses on the current understanding of (1) the yield of non-DSB clustered damage induced by ionizing radiation (2) the processing, and (3) biological consequences of non-DSB clustered DNA damage.
Yogo, Akifumi; Daido, Hiroyuki; Fukumi, Atsushi*; Li, Z.*; Ogura, Koichi; Sagisaka, Akito; Pirozhkov, A. S.; Nakamura, Shu*; Iwashita, Yoshihisa*; Shirai, Toshiyuki*; et al.
Physics of Plasmas, 14(4), p.043104_1 - 043104_6, 2007/04
Times Cited Count:62 Percentile:88.22(Physics, Fluids & Plasmas)Fast protons are observed by a newly-developed time-of-flight spectrometer, which provides proton-energy distributions immediately after the irradiation of a laser pulse having an intensity of W/cm onto a 5-m-thick copper foil. The maximum proton energy is found to increase when the intensity of a fs-prepulse arriving 9 ns before the main pulse increases from 10 to 10 W/cm. Interferometric measurement indicates that the preformed-plasma expansion at the front surface is smaller than 15 m, which corresponds to the spatial resolution of the diagnostics. This sharp gradient of the plasma makes a beneficial effect on increasing the absorption efficiency of the main-pulse energy, resulting in the increase in the proton energy. This is supported by the result that the X-ray intensity from the laser plasma clearly increases with the prepulse intensity.
Nakagawa, Kazumichi*; Kaneko, Fusae*; Ota, Yoshimi*; Tanaka, Masahito*; Kitada, Tomo*; Agui, Akane; Fujii, Kentaro; Yokoya, Akinari; Watanabe, Kazutoshi*; Yamada, Toru*
Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.271 - 273, 2005/06
Times Cited Count:12 Percentile:50.42(Spectroscopy)no abstracts in English
*; *; *; *; *; *; Harada, Hiro; ; Kume, Etsuo;
JAERI-Data/Code 97-055, 161 Pages, 1998/01
no abstracts in English
*; *; *; *; *; *; Harada, Hiro; ; Kume, Etsuo;
JAERI-Data/Code 97-052, 160 Pages, 1997/12
no abstracts in English
*; *; *; *; *; *; Harada, Hiro; ; Kume, Etsuo;
JAERI-Data/Code 97-051, 142 Pages, 1997/12
no abstracts in English
*; Kato, Katsumi*; Kume, Etsuo;
JAERI-Tech 97-028, 37 Pages, 1997/07
no abstracts in English
; *
Syst. Comput. Jpn., 28(4), p.25 - 35, 1997/00
no abstracts in English
; *
Gazo Rabo, 0(11), p.32 - 35, 1996/11
no abstracts in English
*; *; *; *; Harada, Hiro; Gorai, Kazuo; ; ;
JAERI-Data/Code 96-022, 362 Pages, 1996/07
no abstracts in English
; *
Denshi Joho Tsushin Gakkai Rombunshi, D-II, J79-D-2(5), p.775 - 784, 1996/05
no abstracts in English
Ibaraki Daigaku Hakase Rombun, 0, 82 Pages, 1996/03
no abstracts in English
Fumizawa, Motoo; Kunugi, Tomoaki; Hishida, Makoto; *; Fujii, Sadao*; Igarashi, Minoru*
Nuclear Technology, 110, p.263 - 272, 1995/05
Times Cited Count:4 Percentile:43.25(Nuclear Science & Technology)no abstracts in English
; *; *; *; Yokokawa, Mitsuo;
JAERI-Data/Code 94-021, 119 Pages, 1995/01
no abstracts in English
; Higuchi, Kenji; ; Harada, Hiro; ; *; *
High Performance computing 1995; Grand Challenges in Computer Simulation, 0, p.9 - 15, 1995/00
no abstracts in English
; Higuchi, Kenji; ; Kume, Etsuo; ; Ebihara, Kenichi; Otani, Takayuki
JAERI-M 94-051, 109 Pages, 1994/03
no abstracts in English