1. Research
Center for Radiation Protection, National Institute of Radiological Sciences, 491 Anagawa, Inage, Chiba 263-8555, Japan
2. State
Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China
3. Project
for Environmental Dynamics and Radiation Effects, Fukushima Project
Headquarters, National Institute of Radiological Sciences, 491 Anagawa, Inage, Chiba 263-8555, Japan
4. Department
of Biology, Ohu University, 31-1 Koriyama, Fukushima 963-8611, Japan