Affiliation: | 1. Research Service (151), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, California;2. Geriatric Research, Education and Clinical Center (11E), Veterans Affairs Greater Los Angeles Healthcare System, Sepulveda, California;3. Department of Medicine, University of California, Los Angeles, California;4. Interdepartmental Program in Biomedical Engineering, University of California, Los Angeles, California |