1. Radiation Biology Department, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
2. Institute of Atomic and Subatomic Physics (ATI), Vienna University of Technology, Vienna, Austria.
3. Department of Radiation Physics and Dosimetry, Institute of Nuclear Physics (IFJ), Krakow, Poland.
4. Belgian Nuclear Research Centre (SCK·CEN), Mol, Belgium.