1. Harvard-MIT Program in Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
2. Institute of Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
3. Department of Mechanical Engineering, Technical University of Munich, Munich, Germany.
4. School of Mechanical and Aerospace Engineering, Queens University, Belfast, United Kingdom.
5. Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.