Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Onuki, Toshihiko; Ozaki, Takuo; Yoshida, Takahiro*; Nankawa, Takuya; Kozai, Naofumi; Sakamoto, Fuminori; Suzuki, Yoshinori*; Francis, A. J.
no journal, ,
We have been conducting basic studies on the microbial accumulation of actinides in order to understand the environmental behavior of actinides under relevant conditions. The effect of bacterial exudates on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log Kd of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. However, thelog Kd of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results suggests that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris.
Nankawa, Takuya; Suzuki, Yoshinori*; Ozaki, Takuo; Onuki, Toshihiko; Francis, A. J.
no journal, ,
We investigated the electronic interaction between surface-immobilized cytochrome C of Saccharomyces cerevisiae and uranium(VI). First, we immobilized cytochrome C on indium-tin-oxide (ITO) electrode surface by immersing ITO into cytochrome C solution. The peak position of absorption band of cytochrome C on ITO was changed between 410 and 415 nm with the electrode potential sweep from 0 to -0.4 V at pH 7, indicating cyotochrome C was electrochemically active. By adding U(VI)-oxalate or U(VI)-carbonate (U(VI): 1 mM, oxalate or carbonate : 50 mM), the reduction current was enhanced compared to the reduction current of cytochrome C alone and the peak position of absorption band of cytochrome C changed between 410 and 415 nm with the electrode potential sweep. Without cytochrome C, reduction of U(VI) were not observed above -0.5V at pH 7. These results indicate that the reduction of U(VI)-oxalate and U(VI)-carbonate complexes were catalyzed by surface-immobilized reduced cytochrome C.
Nagame, Yuichiro; Akiyama, Kazuhiko*; Asai, Masato; Goto, Shinichi*; Haba, Hiromitsu*; Ishii, Yasuo; Kasamatsu, Yoshitaka; Nishinaka, Ichiro; Tome, Hayato; Toyoshima, Atsushi; et al.
no journal, ,
To perform rapid and repetitive chromatographic experiments with the heaviest elements on an atom-at-a-time basis, we developed an automated rapid ion-exchange separation apparatus AIDA (Automated Ion-exchange separation apparatus coupled with the Detection system for Alpha-spectroscopy). AIDA consists of a modified ARCA (Automated Rapid Chemistry Apparatus) which is a miniaturized computer controlled high performance liquid chromatography system and an automated on-line -particle detection system. It enables us to perform cyclic discontinuous column chromatographic separations of short-lived nuclides in aqueous solutions and automated detection of -particles within a typical cycle of 1-2 min. An elution curve of element 104, rutherfordium (Rf), in anion-exchange chromatography was obtained for the first time with AIDA. The progress of aqueous chemistry of Rf and research plans for extending chemical studies of the heaviest elements at JAEA will be also discussed.