1. Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA
2. Department of Anatomy College of Medicine, Nursing, and Health Sciences National University of Ireland Galway Galway H91 TK33 Ireland
3. Department of Biomedical Engineering School of Engineering College of Science and Engineering National University of Ireland Galway Galway H91 TK33 Ireland
4. Division of Endocrinology, Metabolism & Lipid Research Washington University School of Medicine St. Louis MO 63110 USA
5. Department of Biomedical Engineering Washington University in St. Louis St. Louis MO 63110 USA
6. Advanced Materials and BioEngineering Research Centre (AMBER) Trinity College Dublin Dublin D02 PN40 Ireland
7. CÚRAM, Centre for Research in Medical Devices National University of Ireland Galway Galway H91 TK33 Ireland
8. Department of Mechanical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA