1. German Aerospace Center (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Cologne, Germany.
2. National Institute of Radiological Sciences (NIRS), Research Center for Charged Particle Therapy, Heavy-Ion Radiobiology Research Group, Chiba-shi, Japan.
3. University of Florida, Department of Microbiology and Cell Science, Space Life Sciences Laboratory, Kennedy Space Center, Florida, USA.