1. Cox Laboratory for Biomedical Engineering, Institute of Biosciences and Bioengineering and Department of Chemical Engineering, Rice University, Houston, Texas 77005-1892.
2. Department of Civil Engineering, Rice University, Houston, Texas 77005-1892.
3. Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN 55905.
4. Department of Orthopaedic Surgery, University of Texas M.D. Anderson Cancer Center, Houston, Texas, 77030.
5. Department of Chemistry, Rice University, Houston, Texas 77005-1892.