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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:23.19(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.
Koarai, 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:53.20(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.
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:38.85(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:52.06(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.
Ishikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.
Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05
Times Cited Count:4 Percentile:43.57(Physics, Nuclear)Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.
Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09
Nakajima, Taro*; Mitsuda, Setsuo*; Takahashi, Keiichiro*; Yoshitomi, Keisuke*; Masuda, Kazuya*; Kaneko, Chikafumi*; Homma, Yuki*; Kobayashi, Satoru*; Kitazawa, Hideaki*; Kosaka, Masashi*; et al.
Journal of the Physical Society of Japan, 81(9), p.094710_1 - 094710_8, 2012/09
Times Cited Count:13 Percentile:63.06(Physics, Multidisciplinary)Hosaka, Koichi; Itakura, Ryuji; Yokoyama, Keiichi; Yamanouchi, Kaoru*; Yokoyama, Atsushi
Chemical Physics Letters, 475(1-3), p.19 - 23, 2009/06
Times Cited Count:12 Percentile:38.27(Chemistry, Physical)In intense laser fields, molecules are decomposed into fragments through a number of competing dissociative ionization pathways. We investigate the dissociative ionization dynamics of ethanol in intense laser fields with photoelectron-photoion coincidence momentum imaging. The channel-specific photoelectron spectra reveal the electronic states prepared just after ionization, depending both on the decomposition pathways and on the temporal profile of laser pulses.
Ito, Takanori*; Shirasaki, Saori*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 77(2), p.161 - 168, 2009/02
Times Cited Count:3 Percentile:8.20(Electrochemistry)We analyzed the mechanism of mixed conduction due to electrons and oxygen ions in (LaSr
)MnO
and (Ba
Sr
)(Co
Fe
)O
through the Rietveld refinement and maximum entropy method analyses of neutron and synchrotron X-ray diffractions. It was found that Mn-O plane in (La
Sr
)MnO
has a strong, isotropic covalent bond that enables conduction of electrons. The (Co, Fe)-O2 plane with a covalent bond and a low concentration of oxygen vacancies in (Ba
Sr
)(Co
Fe
)O
can also conduct electrons. On the other hand, the (Ba, Sr)-O1 plane in (Ba
Sr
)(Co
Fe
)O
, which has a high concentration of oxygen vacancies, large isotropic displacement parameter, and a strong ionic bond, is responsible for the diffusion of oxygen ions.
Ito, Takanori*; Nishida, Yuki*; Tomita, Aya*; Fujie, Yoshinori*; Kitamura, Naoto*; Idemoto, Yasushi*; Osaka, Keiichi*; Hirosawa, Ichiro*; Igawa, Naoki
Solid State Communications, 149(1-2), p.41 - 44, 2009/01
Times Cited Count:36 Percentile:77.47(Physics, Condensed Matter)The crystal structure and charge density of (BaSr
)(Co
Fe
)O
were investigated by the Rietveld refinement method and the maximum entropy method by using neutron and synchrotron X-ray diffraction. The crystal structure was refined by using the split atom model to cation sites with the space group,
. The site occupancies of O1(4
) and O2(8
) sites were 0.59 and 0.87, respectively. It was found that the (Co, Fe)-O2 plane in the sample has anisotropic covalent and ionic bands, and that the (Ba, Sr)-O1 bond was ionic with a low charge density.
Koarai, Kazuma; Matsueda, Makoto; Fujiwara, Kenso; Ono, Takumi*; Kino, Yasushi*; Oka, Toshitaka; Okutsu, Kenichi*; Takahashi, Atsushi*; Suzuki, Toshihiko*; Shimizu, Yoshinaka*; et al.
no journal, ,
We have investigated incorporation of Sr and
Cs in teeth of cattle and otoliths of fish. Specific activity of
Sr in the dentin tissue was higher than that in the enamel tissue. The result shows change of
Sr incorporation in cattle even within a tooth. Concentrations of stable Sr and Cs were 94 ppm and 3 ppb. Distributions of stable Sr and Cs were uniform in the otolith of fish. If distribution of
Sr and
Cs in the otolith was measured, change of
Sr and
Cs incorporation into the fish would be found. These findings suggest that distribution patterns of
Sr and
Cs in the environment could be estimated from distribution of the radionuclides in the tooth and otolith.
Koarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Fujiwara, Kenso; Terashima, Motoki; Kino, Yasushi*; Oka, Toshitaka; Okutsu, Kenichi*; Yamashita, Takuma*; et al.
no journal, ,
We demonstrated a method of Sr measurement in small pieces of hard tissues with radioactivity measurement or ICP-MS measurement. Interference elements of the measurements were removed by chemical separation. We could determine
Sr in 0.1 g of hard tissues by radioactivity measurement method and ICP-MS method. Limit of detection of the ICP-MS method was lower than that of the radioactivity measurement. The ICP-MS method is adequate method for distribution analysis of
Sr in the hard tissues.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
no journal, ,
The improvement of the ESR dosimetry is required to apply that for the low-dose exposure of wild animals. We will report our progress of the improvement, and compare the external exposure dose estimated by the ESR dosimetry technique and the calculated result based on the external exposure dose rate of the captured point.
Oka, Toshitaka; Takahashi, Atsushi*; Mitsuyasu, Yusuke*; Koarai, Kazuma; Kino, Yasushi*; Okutsu, Kenichi*; Yamashita, Takuma*; Sekine, Tsutomu*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.
no journal, ,
Electron spin resonance (ESR) dosimetry technique is a powerful tool that has been used in the study of external exposure dose assessment of human by measuring CO radicals of teeth. In this work, we applied this technique for wild monkey and wild racoon captured in Fukushima prefecture, and estimated the external exposure dose.
Koarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
no journal, ,
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.
Koarai, Kazuma; Matsueda, Makoto; Aoki, Jo; Yanagisawa, Kayo*; Terashima, Motoki; Fujiwara, Kenso; Kino, Yasushi*; Oka, Toshitaka; Takahashi, Atsushi*; Suzuki, Toshihiko*; et al.
no journal, ,
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. The ICP-MS method was improved by ICP-MS/MS and oxygen-ammonia mixed gas reaction.
Mitsuyasu, Yusuke*; Oka, Toshitaka; Takahashi, Atsushi*; Kino, Yasushi*; Okutsu, Kenichi*; Sekine, Tsutomu*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; Suzuki, Toshihiko*; et al.
no journal, ,
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011 resulted in a release of radionuclides into the environment and caused chronic low-dose-rate exposure to wildlife there. Studies of the radiobiological effects by the chronic low-dose-rate exposure was limited and there is a need for accurate determination of exposure doses and further studies of radiation effects by FDNPP accident. We determined dose of wild animals mainly captured in Namie Town, Fukushima Prefecture from the CO radical intensities in tooth enamel by an electron spin resonance dosimetry.