1. Department of Pharmaceutical Sciences, West Virginia University, School of Pharmacy, Morgantown, West Virginia 26506, United States
2. In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, United States
3. Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80210, United States