1. a Prevention Research Center, the Carman and Ann Adams Department of Pediatrics , Wayne State University , Detriot , MI , USA
2. b National Center for AIDS/STD Control and Prevention , Chinese CDC , China
3. c Division of HIV/AIDS , Dehong Prefecture Anti-Epidemic Station, Yunnan Province , China
4. d Division of AIDS , Longchuan County Anti-Epidemic Station, Yunnan Province , China
5. e Division of Cancer Epidemiology and Genetics , National Cancer Institute, NIH , USA
6. f Carman and Ann Adams Department of Pediatrics , Wayne State University , Detroit , MI , USA