1. Department of Chemistry, Sam Houston State University, Huntsville, TX, USA;
2. Department of Chemistry and Biochemistry, South Dakota State University, Brookings, SD, USA;
3. Department of Medicine, University of California, San Diego, CA, USA;
4. Department of Mathematics and Statistics, Sam Houston State University, Huntsville, TX, USA;
5. US Army Medical Research Institute of Chemical Defense, APG, MD, USA