1. Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 208521;
2. Theoretical Biology and Biophysics, Group T-10, Los Alamos National Laboratory, Los Alamos, New Mexico 875452;
3. Cercopan, Calabar, CRS, Nigeria3; and
4. Bioqual, Inc., Rockville, Maryland, 208504