1. College of Clinical Medicine, Ningxia Medical University, Yinchuan, Ningxia 750004, China
2. Ningxia Key Laboratory of Clinical and Pathological Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China
3. Ningxia Institute for Stem Cell Research, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China
4. College of Life Science, Ningxia University, Yinchuan, Ningxia 750021, China