1. Key Laboratory of Environmental Health and Chronic Disease Prevention and Control, School of Public Health, Ningxia Medical University, Yinchuan, Ningxia, People's Republic of China.
2. Department of Radiology, the General Hospital, Ningxia Medical University, Yinchuan, Ningxia, People's Republic of China.
3. Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, PLA Air Force Military Medical University, Xi'an, People's Republic of China.
4. Key Laboratory of Fertility Preservation and Maintenance (Ministry of Education), The School of Basic Medicine and General Hospital, Ningxia Medical University, Yinchuan, Ningxia, People's Republic of China.