1. Consumer and Clinical Radiation Bureau, Health Canada, Ottawa, Ontario, Canada
2. Section Radiation Biology, Federal Office for Radiation Protection (BfS), Neuherberg, Germany
3. Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
4. Biology and Environmental Chemistry Division, Sustainable System Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), Komae, Tokyo, Japan