1. Vanderbilt University Institute of Imaging Science (VUIIS) Department of Radiology Department of Biomedical Engineering Department of Physics Vanderbilt-Ingram Cancer Center (VICC) Nashville Tennessee 37232-2310 USA
2. Southern Illinois University Department of Chemistry and Biochemistry, Materials Technology Center Carbondale IL 62901 USA
3. Departments of Chemistry Duke University 124 Science Drive Durham NC 27708 USA
4. Russian Academy of Sciences Leninskiy Prospekt 14 119991 Moscow Russia