We develop a kinetic reaction model for cells having irradiated DNA molecules due to ionizing radiation exposure. Our theory simultaneously accounts for the time-dependent reactions of the DNA damage, the DNA mutation, the DNA repair, and the prolife
ration and apoptosis of cells in a tissue with a minimal set of model parameters. In contrast to existing theories for radiation exposition, we do not assume the relationships between the total dose and the induced mutation frequency. Our theory provides a universal scaling function that reasonably explains the mega-mouse experiments in Ref.[W. L. Russell and E. M. Kelly, Proc. Natl. Acad. Sci. USA. {bf 79} (1982) 542.] with different dose rates. Furthermore, we have estimated the effective dose rate, which is biologically equivalent to the ionizing effects other than those caused by artificial irradiation. This value is $ 1.11 times 10^{-3} ~rm{[Gy/hr]}$, which is significantly larger than the effect caused by natural background radiation.
Hideki Yukawa, Sin-itiro Tomonaga and Shoichi Sakata pioneered nuclear and particle physics and left enduring legacies. Their friendly collaboration and severe competition laid the foundation to bring up the active postwar generation of nuclear and p
article physicists in Japan. In this presentation we illustrate milestones of nuclear and particle physics in Japan from 1930s to mid-1940s which have been clarified in Yukawa Hall Archival Library, Tomonaga Memorial Room and Sakata Memorial Archival Library.
