1. Department of Osteology and Biomechanics, University Medical Center Hamburg, D-22529 Hamburg, Germany.
2. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
3. Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
4. Department of Medical Biometry and Epidemiology, University Medical Center Hamburg, D-20246 Hamburg, Germany.
5. Institute of Pathology, University Medical Center Hamburg, D-20246 Hamburg, Germany.
6. Department of Forensic Medicine, University Medical Center Hamburg, D-20246 Hamburg, Germany.