[1] Univ Kentucky, Dept Chem, Lexington, KY 40506 USA
[2] Univ Kentucky, Spinal Cord & Brain Injury Res Ctr, Lexington, KY USA
[3] Univ Kentucky, Sanders Brown Ctr Aging, Lexington, KY 40506 USA
[4] Eastern Kentucky Univ, Dept Chem, Richmond, KY 40475 USA