1. Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, Illinois.
2. Research Service, Edward Hines, Jr. V.A. Hospital, Hines, Illinois.
3. Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, Texas.
4. Department of Electrical and Computer Engineering, Illinois Institute of Technology, Chicago, Illinois.
5. Research Service, Audie L. Murphy Memorial V.A. Hospital, San Antonio, Texas.