1. Public Health School, Mudanjiang Medical University, Mudanjiang, China
2. The Second Affiliated Hospital, Mudanjiang Medical University, Mudanjiang, China
3. Nursing School, Mudanjiang Medical University, Mudanjiang, China
4. Nursing School, Heilongjiang Nursing College, Harbin, China
5. Collaborative Research Center, Shanghai University of Medicine and Health Sciences, Shanghai, China