1. Department of Obstetrics Affiliated Hospital of Jining Medical University Guhuai Road 89 Jining 272001 China
2. Department of Clinical Medicine Jining Medical University Jining 272001 China
3. Department of Mammary gland Surgery Affiliated Hospital of Jining Medical University Jining 272001 China
4. Departments of Thoracic Surgery Qinghai Red Cross Hospital Xining 272001 China