1. Clinical Nursing Teaching and Research Section, The Second Xiangya Hospital and Xiangya School of Nursing, Central South University, Changsha, China;
2. School of Nursing, University of California, San Francisco, CA, USA;
3. Philip R. Lee Institute for Health Policy Studies and Department of Family and Community Medicine School of Medicine, University of California, San Francisco, CA, USA;
4. Clinical Nursing Teaching and Research Section and Department of Obstetrics, The Second Xiangya Hospital, Central South University, Changsha, China