102 research outputs found

    Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --

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    Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the background radiation level of other regions/countries

    Study on the currents in Lake Biwa (II)

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    Radiation-induced growth inhibition in transplanted human tongue carcinomas with different p53 gene status

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    BACKGROUND AND PURPOSE: To test p53-dependency in radiation cancer therapy with X-rays (low-linear energy transfer (LET)) or carbon-ion (C-) beams (high-LET heavy ion), we analyzed the radiation-induced growth rate and apoptosis induction in human tongue carcinomas transplanted into nude mice. MATERIALS AND METHODS: The SAS cells transfected with mutant p53 gene (SAS/mp53) or a neo control gene (SAS/neo) were transplanted into the thigh of each nude mouse. By measuring the tumor weight (TW), tumor regrowth delay was evaluated when the relative tumor weight (RW) reached 5-fold that of the control group. Apoptosis was analyzed by immunohistochemical and ApopTag stainings. RESULTS: SAS/mp53 tumors were more resistant to X-ray irradiation than SAS/neo tumors, but not to C-beam irradiation. The relative biological effectiveness (RBE) of C-beams compared to X-rays was 2.1 in SAS/neo tumors and 2.6 in SAS/mp53 tumors. Apoptotic cells were more frequently observed in SAS/neo tumors than in SAS/mp53 tumors in X-ray irradiation but not in C-beam irradiation. CONCLUSION: The radiation-induced growth inhibition of transplanted SAS cells is suggested to be p53-dependent in X-ray irradiation but not in C-beam irradiation. C-beams are proposed as being useful for cancer radiation therapy regardless of p53 gene status
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