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Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
Radiation Protection Dosimetry, 199(14), p.1620 - 1625, 2023/09
Times Cited Count：0 Percentile：0.01(Environmental Sciences)We have been conducting dose assessments for Japanese macaques captured in Fukushima to reveal radiobiological effects on the low-dose expose animals. To accurately determine the external exposure dose, it is desirable to examine the analysis of the CO
radical intensity. We examined ESR spectra of teeth of 10 macaques captured in Fukushima by two spectrum-decomposition algorithms.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
KEK Proceedings 2022-2, p.120 - 125, 2022/11
We investigate the effect of sample's anisotropy and measurement condition to obtain the higher reproducibility for the shape of the ESR spectrum and the intensity of CO radical.
Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; Sasaki, Keiichi*; et al.
Journal of Radiation Research (Internet), 63(4), p.609 - 614, 2022/07
Times Cited Count：1 Percentile：27.14(Biology)Electron spin resonance (ESR) dosimetry is one of the most powerful tools for radiation dose reconstruction. The detection limit of this technique using human teeth is reported to be 56 mGy or 67 mGy; however, the absorbed dose of Fukushima residents after the Fukushima Daiichi Nuclear Power Plant (FNPP) accident was estimated to be lower than this detection limit. Our aim is to assess the absorbed radiation dose of children in Fukushima Prefecture after the accident; therefore, it is important to estimate the detection limit for their teeth. The detection limit for enamel of deciduous teeth of Japanese children separated by the mechanical method is estimated to be 115.0 mGy. The density separation method can effectively separate enamel from third molars of Japanese people. As we have collected thousands of teeth from children in Fukushima, the present technique may be useful to examine their external absorbed dose after the FNPP accident.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
KEK Proceedings 2021-2, p.91 - 96, 2021/12
We examined whether the ESR dose estimation method could be applied to wild Japanese macaque. In this work, we investigated the enamel preparation protocol and the analytical method of the ESR spectra.
Sr in cattle bone and tooth samples by inductively coupled plasma mass spectrometryKoarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
Journal of Analytical Atomic Spectrometry, 36(8), p.1678 - 1682, 2021/08
Times Cited Count：5 Percentile：55.72(Chemistry, Analytical)Rapid analysis of Sr in bone and tooth samples of cattle were achieved by an inductively coupled plasma mass spectrometry (ICP-MS) coupled with mass shift and solid phase extraction techniques. Limit of detection (LOD) in the ICP-MS measurement of 0.1 g samples was lower than that of the radioactivity measurement. Analytical time of the ICP-MS method was reduced from 20 days to 11 hours, compared with the radiometric method. Therefore, the ICP-MS method can be rapid and useful procedure of Sr in small bone and tooth samples derived from terrestrial animals.
Kozai, Naofumi; Sato, Junya; Osugi, Takeshi; Shimoyama, Iwao; Sekine, Yurina; Sakamoto, Fuminori; Onuki, Toshihiko
Journal of Hazardous Materials, 416, p.125965_1 - 125965_9, 2021/08
Times Cited Count：24 Percentile：85.21(Engineering, Environmental)Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.
Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05
Times Cited Count：6 Percentile：41.49(Multidisciplinary Sciences)Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Mitsuyasu, Yusuke*; Kino, Yasushi*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; Osaka, Ken*; et al.
Radiation Measurements, 134, p.106315_1 - 106315_4, 2020/06
Times Cited Count：5 Percentile：53.85(Nuclear Science & Technology)The relationship between the CO
radical intensity and the absorbed dose (dose response curve) of tooth enamel of Japanese macaque was observed by electron spin resonance and the detection limit of our system was estimated to be 33.5 mGy, which is comparable to the detection limit for human molar teeth. Using the dose response curve, external exposure dose for seven wild Japanese macaques captured in Fukushima prefecture were examined. The results suggest that the external exposure dose for the wild Japanese macaques were ranged between 45 mGy to 300 mGy.
Sekine, Yurina; Motokawa, Ryuhei; Kozai, Naofumi; Onuki, Toshihiko; Matsumura, Daiju; Tsuji, Takuya; Kawasaki, Riku*; Akiyoshi, Kazunari*
Scientific Reports (Internet), 7(1), p.2064_1 - 2064_8, 2017/05
Times Cited Count：35 Percentile：75.89(Multidisciplinary Sciences)A calcium (Ca)-deficient hydroxyapatite was investigated for its potential to remove Sr
from environmentally relevant water. We conducted sorption tests on solutions having Mg and Ca as competing cations at the Sr concentration of 0.05 mmol/L. The Ca-deficient hydroxyapatite maintained its high Sr sorption ratio: the sorption ratio was above 80% in the presence of Mg and Ca in the concentrations between 0.1 to 1.0 mmol/L, whereas stoichiometric hydroxyapatite showed a lower ratio even in the presence of small amounts of Mg and Ca. The bonding states of Sr onto the Ca-deficient hydroxyapatite were evaluated by extended X-ray absorption fine structure measurements. The results indicated that there are specific sorption sites in Ca-deficient hydroxyapatite where Sr could be stably and preferentially immobilized.
Sekine, Toshihiko; Sawada, Shinichi; Yamaki, Tetsuya; Asano, Masaharu; Suzuki, Akihiro*; Terai, Takayuki*; Yoshida, Masaru
Transactions of the Materials Research Society of Japan, 31(4), p.871 - 874, 2006/12
no abstracts in English
Sekine, Toshihiko; Yamaki, Tetsuya; Suzuki, Akihiro*
Tokyo Daigaku Aisotopu Sogo Senta Nyusu, 37(1), p.2 - 5, 2006/06
no abstracts in English
; Onuki, Toshihiko; Isobe, Hiroshi; Yanase, Nobuyuki; Sekine, Keiichi; *; *
Journal of Contaminant Hydrology, 35, p.191 - 199, 1998/00
Times Cited Count：4 Percentile：18.7(Environmental Sciences)no abstracts in English
Onuki, Toshihiko; Yanase, Nobuyuki; Sekine, Keiichi; Isobe, Hiroshi; Nagano, Tetsushi; Sakamoto, Yoshiaki
Journal of Nuclear Science and Technology, 34(12), p.1153 - 1158, 1997/12
Times Cited Count：26 Percentile：86.43(Nuclear Science & Technology)no abstracts in English
; Sato, Tsutomu; Nagano, Tetsushi; Yanase, Nobuyuki; Yamaguchi, Tetsuji; Isobe, Hiroshi; Onuki, Toshihiko; Sekine, Keiichi
JAERI-Review 95-011, 94 Pages, 1995/07
JAERI-Review-95-011.pdf:4.81MB
no abstracts in English
Onuki, Toshihiko; Murakami, Takashi; Sekine, Keiichi; Yanase, Nobuyuki; Isobe, Hiroshi; Kobayashi, Yoshii
Materials Research Society Symposium Proceedings, Vol. 176, p.607 - 614, 1990/00
no abstracts in English
Yamaki, Tetsuya; Sekine, Toshihiko; Sawada, Shinichi; Asano, Masaharu; Terai, Takayuki*; Maekawa, Yasunari
no journal, ,
no abstracts in English
Yamaki, Tetsuya; Sawada, Shinichi; Asano, Masaharu; Yoshida, Masaru; Maekawa, Yasunari; Sekine, Toshihiko; Terai, Takayuki*
no journal, ,
no abstracts in English
Yamaki, Tetsuya; Sawada, Shinichi; Sekine, Toshihiko; Asano, Masaharu; Terai, Takayuki*; Maekawa, Yasunari
no journal, ,
no abstracts in English
Yamaki, Tetsuya; Sawada, Shinichi; Sekine, Toshihiko; Asano, Masaharu; Nishimura, Hidetoshi*; Suzuki, Akihiro*; Terai, Takayuki*; Maekawa, Yasunari
no journal, ,
no abstracts in English
Sekine, Toshihiko; Sawada, Shinichi; Yamaki, Tetsuya; Asano, Masaharu; Suzuki, Akihiro*; Terai, Takayuki*; Maekawa, Yasunari
no journal, ,
A tracer permeation technique was applied as the only way to detect water transport in polymer electrolyte membranes (PEMs) immersed in a water/methanol mixture. As a first step, we investigated the applicability of a tritiated water (HTO) tracer method comparing with the results from a heavy oxygen water (H
O) tracer. According to a simple isotopic-exchange theory, the measured HTO permeation coefficient, P(HTO), is assumed to depend on the abundance ratio between HO and CH
OH in the solution used for the permeation experiments. This assumption enabled us to estimate the effective permeability of HTO, P(HTO)
. Importantly, we noticed a rather small difference between the P(HTO) and P(HO) values, which probably indicates that HTO mobility was affected by the different T/H substitution rates due to hydrogen-bonding interaction with polar sulfonic acid groups in PEMs.
