1. Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas 77555, United States
2. Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, Texas 77555, United States
3. The Radiation Effects Research Foundation (RERF), Hiroshima and Nagasaki 732-0815, Japan
4. Radiation Oncology, The University of Texas Medical Branch, Galveston, Texas 77555, United States