北京市卫生系统高层次卫生技术人才培养计划(No.2011-2-09),国家自然科学基金项目(No.81173237),北京市自然科学基金项目(No.7142053)%Training Program of High-level Technical Talents in Beijing Health System (No.2011-2-09),National Natural Science Foundation of China (No.81173237),Natural Science Foundation of Beijing (No.7142053)