1. Department of Mechanical EngineeringCarnegie Mellon University Pittsburgh PA 15213 USA
2. Research and Development EngineeringSiemens Corporate Technology Princeton NJ 08540 USA
3. Department of Biomedical EngineeringCarnegie Mellon University Pittsburgh PA 15213 USA
4. Department of Materials Science and EngineeringCarnegie Mellon University Pittsburgh PA 15213 USA