1 Key Laboratory of Environmental Factors and Chronic Disease Control, School of Public Health and Management, Ningxia Medical University Yinchuan 750004 China.
2 College of Chemistry & Chemical Engineering, Ningxia University Yinchuan 750021 China ping@nxu.edu.cn.
3 School of Basic Medical Sciences, Ningxia Medical University Yinchuan 750004 China huiqin_yao@163.com.