1. Department of Chemistry Brown University Providence RI 02912 USA
2. Department of Chemistry Washington State University Pullman WA 99164 USA
3. School of EECS Washington State University Pullman WA 99164 USA
4. Division of Cancer Epidemiology and Genetics NCI, NIH Rockville MD 20850 USA
5. Department of Computer Science & Engineering Texas A&M University College Station Texas TX 77843 USA