1. Department of Geriatrics, Neurosciences and Orthopedics, Catholic University of the Sacred Heart School of Medicine, Rome, Italy;
2. Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma;
3. Department of Aging and Geriatric Research, Institute on Aging, University of Florida, Gainesville, Florida; and
4. Institute of Crystallography, Italian National Research Council, Bari, Italy