1. Department of Chemistry, Texas A & M University, Box 30012, College Station, Texas 77842, United States
2. Department of Radiology, University of Wisconsin−Madison, Madison, Wisconsin 53705, United States
3. Department of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China
4. University
of Wisconsin Carbone Cancer Center, University of Wisconsin−Madison, Madison, Wisconsin 53705, United States
5. Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia