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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：86.19(Engineering, Environmental)Onuki, Toshihiko; Aiba, Yukitoshi*; Sakamoto, Fuminori; Kozai, Naofumi; Niizato, Tadafumi; Sasaki, Yoshito
Scientific Reports (Internet), 6, p.29866_1 - 29866_6, 2016/07
Times Cited Count：10 Percentile：31.09(Multidisciplinary Sciences)We here first report the direct accumulation pathway of radioactive Cs from contaminated wood logs to the fruit-bodies of shiitake mushrooms through the basal portion of the stipe by using 
spectroscopy, autoradiography, and X-ray micro CT techniques.
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Shiotsu, Hiroyuki; Utsunomiya, Satoshi*
no journal, ,
Accumulation of Cs by unicellular fungus of Saccharomyces cerevisiae in the presence of minerals have been studied to elucidate the role of microorganisms in the migration of radioactive Cs in the environment. With carbon source, higher amounts of Cs was accumulated in the cells than in the resting condition without carbon source. In the presence of mineral in the agar medium, the radioactivity in the yeast cells with different minerals were in the order of the inverse of Kd of minerals. These results strongly suggest that the yeast accumulates radioactive Cs competitively with minerals.
Onuki, Toshihiko; Kozai, Naofumi; Sakamoto, Fuminori
no journal, ,
The migration behavior of radiocesium in plants and soil collected in Fukushima, Japan have been studied by the analyses of contaminated plants and soil using autoradiography, sequential desorption, size fractionation, XRD, and SEM analysis. Results showed that plants and soil act as retardation barrier in the migration of radiocesium.
Sakamoto, Fuminori; Onuki, Toshihiko; Kozai, Naofumi
no journal, ,
no abstracts in English
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya*; Yu, Q.
no journal, ,
We have examined the accumulation of radioactive Cs by mycelia of filamentous fungi by combining agar medium method with autoradiography (AR) analysis using imaging plate. Radioactive Cs was accumulated in the mycelia of 1500 species of the filamentous fungi between ca. 10 and ca. 1000 times higher than in medium. The presence of minerals in the agar medium reduced the accumulation of radioactive Cs in the mycelia. One of the reasons for the resistance is probably adsorption of radioactive Cs by minerals in the soil. The irreversible accumulation in cells caused excess radioactive Cs in the hyphae than that expected by Kd model.
Okumura, Taiga*; Yamaguchi, Noriko*; Dohi, Terumi; Iijima, Kazuki; Kogure, Toshihiro*
no journal, ,
To determine dissolution rates of radiocesium-bearing microparticles (CsMPs) released by the Fukushima Nuclear accident, we conducted dissolution experiments of CsMPs by reaction with pure water and seawater at several temperatures. According to the experiments, CsMPs may be completely dissolved and extinguished in several decades and several years in pure water and seawater, respectively.
