1. Duke University, Department of Chemistry, Box 90354, Durham, North Carolina 27708-0354, United States
2. Duke University, Department of Chemistry, Box 90354, Durham, North Carolina 27708-0354, United StatesbDuke University Medical Center, Department of Radiology, Box 3808, Durham, North Carolina 27710, United States
3. Duke University Medical Center, Department of Dermatology, DUMC 3135, Durham, North Carolina 27710, United States
4. Duke University, Department of Chemistry, Box 90354, Durham, North Carolina 27708-0354, United StatesbDuke University Medical Center, Department of Radiology, Box 3808, Durham, North Carolina 27710, United StatesdDuke University, Department of Biomedical