1. Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
2. Guiyang Medical College, Guiyang, China
3. Southwest Prefecture Center for Disease Control, Xingyi, Guizhou, China
4. Zunyi Medical College, Zunyi, China