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Shimada, Mikio*; Tokumiya, Takumi*; Miyake, Tomoko*; Tsukada, Kaima*; Kanzaki, Norie; Yanagihara, Hiromi*; Kobayashi, Junya*; Matsumoto, Yoshihisa*
Journal of Radiation Research (Internet), 64(2), p.345 - 351, 2023/03
Times Cited Count：1 Percentile：0.01(Biology)
-Mn under high pressureMiyake, Atsushi*; Kanemasa, Tsunehiro*; Yagi, Ryohei*; Kagayama, Tomoko*; Shimizu, Katsuya*; Haga, Yoshinori; Onuki, Yoshichika
Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.e222 - e224, 2007/03
We have measured electrical resistivity of single crystalline -manganese (-Mn) under high pressure. -Mn shows an antiferromagnetic ordering at 
= 95 K and has four inequivalent crystal sites with different magnetic moments. With increasing pressure, shifts toward lower temperature. At higher pressure, the shape of anomaly at changes to a kink-like one, which may indicate different magnetic ordering from that at lower pressure. Such a difference between lower and higher pressure regions is considered to be caused by the four inequivalent magnetic moments in -Mn. At 1.9 GPa, the boundary of the ordered phases, we observe a sudden decrease of the residual resistivity and a peak of the A-coefficient of 
-term of the resistivity.
Shimada, Mikio*; Tsukada, Kaima*; Miyake, Tomoko*; Kanzaki, Norie; Yanagihara, Hiromi*; Matsumoto, Yoshihisa*
no journal, ,
Induced pluripotent stem cells (iPSCs) are generated by transduction of reprogramming transcriptional factors. iPSCs have multipotency to differentiate all organs and expected for the application of regenerative medicine. However, it is reported that cancer risk of iPSCs, because of expression of reprogramming factors increased DNA damage. It is important to analysis DNA damage response of iPSCs to prevent chromosomal abnormality and tumor formation. In this study, we attempted to elucidate the molecular mechanism of maintenance of genome stability in iPSCs. RNA-seq analysis by the next generation sequencer showed increased expression of genome maintenance genes such as DNA repair, cell cycle checkpoint and apoptosis. Interestingly, expression level of these genes was decreased after differentiation to the neural stem cells. Furthermore, colony formation assay showed high sensitivity and apoptosis activity to the IR exposure in iPSCs. These results suggested that instead of DNA repair, increasing of apoptosis activity maintain cell population having accurate genome DNA. These molecular insight have important implication for safety medical application of iPSCs.
Shimada, Mikio*; Kanzaki, Norie; Yanagihara, Hiromi*; Miyake, Tomoko*; Matsumoto, Yoshihisa*
no journal, ,
Although mutation frequency depends on organ cell types and differentiation level, it is not fully understood that organ cell types dependent mutation frequency in human cells. In this study, we aimed to establish measurement system of radiation dependent mutation frequency for analyze radiation effect to the human body. For this purpose, we derived four different organ cells such as neural cells, skin keratinocytes, heart muscle cells and blood cells from hiPSCs. Further, using artificial intelligence technology and machine leaning method, we w analyzed differences of mutation frequency during samples.
