Kinetic mass transfer behavior of Eu(III) in nitrilotriacetamide-impregnated polymer-coated silica particles

Miyagawa, Akihisa*; Hayashi, Naoki*; Kuzure, Yoshiaki*; Takahashi, Takumi*; Iwamoto, Hibiki*; Arai, Tsuyoshi*; Nagatomo, Shigenori*; Miyazaki, Yasunori; Hasegawa, Kenta; Sano, Yuichi; et al.

Bulletin of the Chemical Society of Japan, 96(7), p.671 - 676, 2023/07

https://doi.org/10.1246/bcsj.20230087

We investigated the distribution mechanism of Eu(III) in a single polymer-coated silica particle including nitrilotriacetamide (NTA) extractants known as HONTA and TOD2EHNTA. The present study provides a valuable approach for the evaluation and enhancement of the functionality of "single extractant-impregnated polymer-coated silica particle".

NHEJ repair rather than HR repair is the primary function to target to enhance radiosensitization at high LET values

Takahashi, Akihisa*; Kubo, Makoto*; Igarashi, Chie*; Yoshida, Yukari*; Funayama, Tomoo; Kobayashi, Yasuhiko; Nakano, Takashi*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 82, 2015/03

https://doi.org/10.11484/jaea-review-2014-050

DNA double-strand breaks (DSBs) induced by ionizing radiation pose a major threat to cell survival. The cell can respond to the presence of DSBs, through two major repair pathways: Homologous recombination (HR) and non-homologous end-joining (NHEJ). Higher levels of cell death are induced by high-LET radiation when compared to low-LET radiation, even at the same doses because of less effective or more inefficient DNA repair. In this study, we examine the effects of radiation with different LET values on DNA DSB repair and radiosensitivity. Wild-type cells and HR deficient (but NHEJ proficient) cells exhibited the high RBE values at LET values of 108 keV/ m. The RBE value for each cell type decreased with increasing LET values over 200 keV/m. Although NHEJ proficient cells had an almost constant SER value, NHEJ deficient cells showed a high SER value when compared to NHEJ proficient cells, even with increasing LET values.

Increase in cell motility by carbon ion irradiation via the Rho signaling pathway and its inhibition by the ROCK inhibitor Y-27632 in lung adenocarcinoma A549 cells

Murata, Kazutoshi*; Noda, Shinei*; Oike, Takahiro*; Takahashi, Akihisa*; Yoshida, Yukari*; Suzuki, Yoshiyuki*; Ono, Tatsuya*; Funayama, Tomoo; Kobayashi, Yasuhiko; Takahashi, Takeo*; et al.

Journal of Radiation Research, 55(4), p.658 - 664, 2014/07

https://doi.org/10.1093/jrr/rru002

The effect of carbon ion irradiation on cell motility through the Rho signaling pathway in the human lung adenocarcinoma cell line A549 was studied. At 48 h after irradiation, the cell motility of A549 cells became significantly greater, and the formation of protrusions significantly increased in cells irradiated with carbon ion. The observed increase in cell motility due to carbon ion irradiation was similar to that observed due to X-ray irradiation. Western-blot analysis showed that carbon ion irradiation increased P-MLC2-S19 expression compared with in unirradiated controls, while total MLC2 expression was unchanged. Exposure to a non-toxic concentration of Y-27632, a specific inhibitor of ROCK, reduced the expression of P-MLC2-S19 after C-ion irradiation, resulting in a significant reduction in migration. These data suggest that carbon irradiation increases cell motility in A549 cells via the Rho signaling pathway and that ROCK inhibition reduces that effect.

Real-time observation of anisotropic strain relaxation by three-dimensional reciprocal space mapping during InGaAs/GaAs(001) growth

Suzuki, Hidetoshi*; Sasaki, Takuo*; Sai, Akihisa*; Oshita, Yoshio*; Kamiya, Itaru*; Yamaguchi, Masafumi*; Takahashi, Masamitsu; Fujikawa, Seiji

Applied Physics Letters, 97(4), p.041906_1 - 041906_3, 2010/07

https://doi.org/10.1063/1.3458695

In situ study of strain relaxation mechanisms during lattice-mismatched InGaAs/GaAs growth by X-ray reciprocal space mapping

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Takahashi, Masamitsu; Fujikawa, Seiji; Oshita, Yoshio*; Yamaguchi, Masafumi*

Materials Research Society Symposium Proceedings, Vol.1268, 6 Pages, 2010/05

https://doi.org/10.1557/PROC-1268-EE06-02

Vanguards of paradigm shift in radiation biology; Radiation-induced adaptive and bystander responses

Matsumoto, Hideki*; Hamada, Nobuyuki*; Takahashi, Akihisa*; Kobayashi, Yasuhiko; Onishi, Takeo*

Journal of Radiation Research, 48(2), p.97 - 106, 2007/03

https://doi.org/10.1269/jrr.06090

The risks of low dose ionizing irradiation ( 100 mSv) have been estimated using a linear no-threshold model by extrapolating from data obtained after high dose irradiation. The validity of this dose-response model is, however, controversial because evidence accumulated for over the past decade has shown that response of living organisms including humans to low dose/low dose-rate radiation is different from that to high dose/high dose-rate radiation. In another words, findings that cannot be explained by the classical "target theory" of radiobiology have accumulated. The radiation-induced adaptive response, bystander effects, low-dose radio-hypersensitivity, and genomic instability are specifically observed in response to low dose/low dose-rate radiation, and underpinnings of these responses often involve biochemical/molecular signals responding to targeted and non-targeted events. Recently, interrelations between the radioadaptive and bystander responses have been increasingly reported. We review observations supporting the existence of the latter two phenomena, and discuss the possible link between them from the aspect of production of reactive oxygen and nitrogen species.

Analysis of mechanisms for radiation-induced bystander effect using heavy-ion microbeams

Matsumoto, Hideki*; Hatashita, Masanori*; Takahashi, Akihisa*; Hamada, Nobuyuki*; Wada, Seiichi*; Kobayashi, Yasuhiko; Funayama, Tomoo; Sakashita, Tetsuya; Kakizaki, Takehiko

no journal, , 

no abstracts in English