1. Department
of Chemistry, Duke University, Durham, North Carolina 27708, United States
2. Vanderbilt
University Institute of Imaging Science (VUIIS), Department of Radiology,
Department of Biomedical Engineering, Vanderbilt Ingram Cancer Center
(VICC), Vanderbilt University, Nashville, Tennessee 37232, United States
3. Russian Academy of Sciences, Moscow, Russia
4. Departments
of Physics, Radiology and Biomedical Engineering, Duke University, Durham, North Carolina 27707, United States