1. Department of gynaecology and obstetrics
2. Lanzhou University Second Hospital
3. Lanzhou
4. PR China
5. Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province
6. State Key Laboratory of Applied Organic Chemistry
7. and Key Laboratory of Special Function Materials and Structure Design
8. Ministry of Education
9. Lanzhou University Gansu
10. Key Laboratory for New Molecule Material Design and Function of Tianshui Normal University
11. Tianshui