1. a Uniformed Services University of the Health Sciences, Department of Preventive Medicine and Biometrics, Bethesda, MD
2. b Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT
3. c Navy Environmental and Preventive Medicine Unit Number Two, Norfolk, VA
4. d Laboratory Directorate, U.S. Army Center for Health Promotion and Preventive Medicine, Edgewood, MD