1. Medical Department Hunan Provincial People’s Hospital, (the First Affiliated Hospital of Hunan Normal University), Changsha P.R. China
2. Department of Nosocomial Infection, Hunan Provincial People’s Hospital, (the First Affiliated Hospital of Hunan Normal University), Changsha, P.R. China
3. Institute of Geriatrics, Hunan Provincial People’s Hospital, (the First Affiliated Hospital of Hunan Normal University), Changsha, P.R. China
4. Department of Neurosurgery, Hunan Provincial People’s Hospital, (the First Affiliated Hospital of Hunan Normal University), Changsha, P.R. China