1. Environmental Public Health Division, National Health & Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency (EPA), Research Triangle Park, North Carolina, USA
2. Integrated Systems Toxicology Division, National Health & Environmental Effects Research Laboratory, Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina, USA
3. Curriculum in Toxicology, University of North Carolina School of Medicine, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA