1. Departments of Mechanical and Biomedical Engineering, University of Utah , Salt Lake City, UT 84112 , USA
2. Advanced Light Source, Lawrence Berkeley Laboratory , Berkeley, CA 94720 , USA
3. Department of Epidemiology and Biostatistics, University of California , San Francisco, CA 94143 , USA
4. Department of Molecular Biosciences, University of California , Davis, CA 95616 , USA
5. Department of Nutrition, University of California , Davis, CA 95616 , USA
6. Materials Science Division, Lawrence Berkeley National Laboratory , Berkeley, CA 94720 , USA
7. Department of Materials Science and Engineering, University of California , Berkeley, CA 94720 , USA
8. Department of Orthopaedic Surgery, University of California , San Francisco, CA 94143 , USA
9. Department of Mechanical and Aerospace Engineering, University of California , San Diego, CA 92093 , USA