1. Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6112, United States
2. Integrated Research Facility, NIAID, NIH, 8200 Research Plaza, Fort Detrick, Frederick, Maryland 21702, United States
3. Department of Chemistry, University of Louisville, Kentucky, United States
4. Department of Anesthesia and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6112, United States