1. Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 e-mail:
2. Mem. ASME Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, NE 68588-0526 e-mail:
3. Department of Surgery, University of Nebraska Medical Center, 986245 Nebraska Medical Center, Omaha, NE 68198 e-mail: