1. Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD 20993, US
2. Drexel University School of Biomedical Engineering Science and Health Systems, Implant Research Center, 3141 Chestnut St., Philadelphia, PA 19104, US
3. University of Tennessee Health Science Center, Campbell Clinic Dept. of Orthopaedic Surgery and Biomedical Engineering, 920 Madison Ave., Memphis, TN 38163, US