1. First Clinical Medical College, Lanzhou University, Lanzhou 730000, China
2. Department of General Surgery, First Hospital of Lanzhou University, Lanzhou 730000, China
3. School of Information Science and Engineering, Lanzhou University, Lanzhou 730000, China
4. The Reproductive Medicine Hospital of the First Hospital of Lanzhou University, Lanzhou 730000, China
5. Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
6. Key Laboratory of Biotherapy and Regenerative Medicine of Gansu Province, Lanzhou 730000, China