a
Materials Science Program, University of Wisconsin-Madison, Madison, USA
b
Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, USA
E-mail: wlmurphy@wisc.edu
;
Fax: +1 608 265 9239
;
Tel: +1 608 262 2224
c
Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, USA
d
AO Foundation Collaborative Research Center, Davos, Switzerland