Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamaguchi, Akiko; Kurihara, Yuichi*; Nagata, Kojiro*; Tanaka, Kazuya; Higaki, Shogo*; Kobayashi, Toru; Tanida, Hajime; Ohara, Yoshiyuki*; Yokoyama, Keiichi; Yaita, Tsuyoshi; et al.
Journal of Colloid and Interface Science, 661, p.317 - 332, 2024/05
Times Cited Count：0no abstracts in English
Yamaguchi, Akiko; Okumura, Masahiko; Takahashi, Yoshio*
Isotope News, (789), p.20 - 23, 2023/10
Radium is a radioactive element produced from uranium and thorium and is important for environmental contamination issues around uranium mines and for geological disposal. In addition, radium is used in radiometric dating and cancer therapy, making it important not only in environmental chemistry but also in many other fields, including geochemistry and nuclear medicine. However, because radium is a radioactive element with no stable isotopes, spectroscopic measurement of radium is difficult, and little information at the molecular level has been obtained so far. In this study, we have clarified the molecular-level information of hydrated radium for the first time in the world by combining extended X-ray absorption fine structure (EXAFS) measurements and first-principles molecular dynamics simulations.
values calculated from radiocesium interception potentialUno, Koichiro*; Nakao, Atsushi*; Okumura, Masahiko; Yamaguchi, Akiko; Kogure, Toshihiro*; Yanai, Junta*
Nihon Dojo Hiryo Gaku Zasshi, 94(5), p.376 - 384, 2023/10
Radiocesium interception potential (RIP) has been widely used as a quantitative indicator of cesium (Cs) adsorption capacity of soil, but it has been found that RIP does not always correlate with the distribution coefficient () of Cs in the actual environment. In order to clarify the cause of this discrepancy, we measured Kd using more realistic solutions, compared it with RIP, and evaluated the mineral structure. As a result, it was found that the concentration of competing cations, such as potassium and ammonium ions, and the structural change of the mineral itself are important.
Yamaguchi, Akiko
Hosha Kagaku, (47), p.41 - 42, 2023/03
Radium (Ra) is essential for various fields, such as environmental chemistry and nuclear medicine. However, even the hydration structure of Ra remains unclear due to the difficulty in the Ra treatment, caused by the fact that Ra has no stable isotopes and forms radon, noble gas. This study measured the extended X-ray absorption fine structure (EXAFS) of Ra to investigate its hydration structure and adsorption structures on clay minerals. The EXAFS results were consistent with our environmental analysis of core samples in a uranium mine.
-edge for Ce in bauxites using transition-edge sensors; Implications for Ti-rich geological samplesLi, W.*; Yamada, Shinya*; Hashimoto, Tadashi; Okumura, Takuma*; Hayakawa, Ryota*; Nitta, Kiyofumi*; Sekizawa, Oki*; Suga, Hiroki*; Uruga, Tomoya*; Ichinohe, Yuto*; et al.
Analytica Chimica Acta, 1240, p.340755_1 - 340755_9, 2023/02
Times Cited Count：2 Percentile：31.9(Chemistry, Analytical)no abstracts in English
Kobayashi, Keita; Yamaguchi, Akiko; Okumura, Masahiko
Applied Clay Science, 228, p.106596_1 - 106596_11, 2022/10
Times Cited Count：6 Percentile：77.65(Chemistry, Physical)no abstracts in English
molecular dynamics simulations reveal the hydration structure of the radium(II) ionYamaguchi, Akiko; Nagata, Kojiro*; Kobayashi, Keita; Tanaka, Kazuya; Kobayashi, Toru; Tanida, Hajime; Shimojo, Kojiro; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08
Times Cited Count：9 Percentile：68.46(Multidisciplinary Sciences)no abstracts in English
Yamaguchi, Akiko; Nagata, Kojiro*; Tanaka, Kazuya; Kobayashi, Keita; Kobayashi, Toru; Shimojo, Kojiro; Tanida, Hajime; Sekiguchi, Tetsuhiro; Kaneta, Yui; Matsuda, Shohei; et al.
Hosha Kagaku, (45), p.28 - 30, 2022/03
no abstracts in English
molecular dynamics simulations using the SCAN meta-GGA density functional and EXAFS spectroscopy studiesYamaguchi, Akiko; Kobayashi, Keita; Takahashi, Yoshio*; Machida, Masahiko; Okumura, Masahiko
Chemical Physics Letters, 780, p.138945_1 - 138945_5, 2021/10
Times Cited Count：5 Percentile：44.89(Chemistry, Physical)no abstracts in English
-edge for the determination of oxidation state for trace amount of Eu in natural samples by bragg-type crystal analyzer systemKonagaya, Rimi*; Kawamura, Naomi*; Yamaguchi, Akiko; Takahashi, Yoshio*
Chemistry Letters, 50(8), p.1570 - 1572, 2021/08
Times Cited Count：3 Percentile：22.95(Chemistry, Multidisciplinary)no abstracts in English
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Kobayashi, Keita; Nakamura, Hiroki; Yamaguchi, Akiko; Itakura, Mitsuhiro; Machida, Masahiko; Okumura, Masahiko
Computational Materials Science, 188, p.110173_1 - 110173_14, 2021/02
Times Cited Count：14 Percentile：73.11(Materials Science, Multidisciplinary)no abstracts in English
Yamaguchi, Akiko; Asano, Ikumi*; Kitagawa, Yuri*; Meng, C.*; Nakao, Atsushi*; Okumura, Masahiko
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.127 - 130, 2020/10
no abstracts in English
Nagasawa, Makoto*; Qin, H.-B.*; Yamaguchi, Akiko; Takahashi, Yoshio*
Chemistry Letters, 49(8), p.909 - 911, 2020/08
Times Cited Count：3 Percentile：10.1(Chemistry, Multidisciplinary)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：259 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Yamaguchi, Akiko*; Honda, Tasuku*; Tanaka, Masato*; Tanaka, Kazuya; Takahashi, Yoshio*
Geochemical Journal, 52(5), p.415 - 425, 2018/00
Times Cited Count：18 Percentile：61.41(Geochemistry & Geophysics)Ion-adsorption type REE deposits in weathered granite are main sources of REE essential for high-technology industries. However, these type deposits have not been searched in Japan. In this study, Bulk REE abundances (= REE
), ion-exchangeable REE (= REE
) by ammonium chloride solution, and percentage of REE relative to REE (= REE
) in fresh and weathered granite samples in Southwest Japan (i.e., Hiroshima and Shimane Prefectures) were determined. The REE and REE were comparable to those of ion-adsorption type REE deposits in China. Extended X-ray adsorption fine structure (EXAFS) spectra of REE in original samples and samples after the extraction of ion-exchangeable REE showed that (i) REE in samples with high REE mainly forms outer-sphere complexes and (ii) the remaining REE in the rocks after the extraction forms inter-sphere complexes.
Masuda, Toshiyuki*; Arase, Junko*; Inagaki, Yusuke*; Kawahara, Masatoshi*; Yamaguchi, Kentaro*; Ohara, Takashi; Nakao, Akiko*; Momma, Hiroyuki*; Kwon, E.*; Setaka, Wataru*
Crystal Growth & Design, 16(8), p.4392 - 4401, 2016/08
Times Cited Count：27 Percentile：87.56(Chemistry, Multidisciplinary)Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Times Cited Count：51 Percentile：71.25(Biochemistry & Molecular Biology)Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
AlOzawa, Akira*; Matsuta, Kensaku*; Nagatomo, Takashi*; Mihara, Mototsugu*; Yamada, Kazunari*; Yamaguchi, Takayuki*; Otsubo, Takashi*; Momota, Sadao*; Izumikawa, Takuji*; Sumikama, Toshiyuki*; et al.
Physical Review C, 74(2), p.021301_1 - 021301_4, 2006/08
Times Cited Count：43 Percentile：89.22(Physics, Nuclear)no abstracts in English
Yamaguchi, Akiko*; Kurihara, Yuichi*; Tanaka, Kazuya; Ohara, Yoshiyuki; Kozai, Naofumi; Takahashi, Yoshio*
no journal, ,
