1. Department of Biomedical Engineering, University of Michigan at Ann Arbor, Ann Arbor, Michigan.
2. Department of Mechanical Engineering, University of Michigan at Ann Arbor, Ann Arbor, Michigan.
3. Department of Neurosurgery, University of Michigan at Ann Arbor, Ann Arbor, Michigan.
4. Department of Biologic and Materials Sciences, University of Michigan at Ann Arbor, Ann Arbor, Michigan.
5. Current affiliation: University of Tennessee Health Science Center, College of Dentistry, Cancer Research Building, Memphis, Tennessee.