1. Department of Biologic & Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
2. Department of Neurology, Medical School, University of Michigan, Ann Arbor, Michigan, USA
3. Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, USA
4. Neurology Service, Veterans Administrator Ann Arbor Healthcare System, University of Michigan, Ann Arbor, Michigan, USA