1. Department of Anesthesiology, Pain Research Center, University of Utah, Salt Lake City, UT.
2. Department of Anesthesiology, West China Hospital, Sichuan University, Sichuan, China.
3. Rehabilitation and Acupuncture Center, West China Hospital, Sichuan University, Sichuan, China.
4. Department of Pediatrics, University of Utah, Salt Lake City, UT.
5. Department of Family and Preventive Medicine, Division of Epidemiology, University of Utah, Salt Lake City, UT.