本文课题受国家自然科学基金项目编号81101915;天津市应用基础及前沿技术研究计划项目编号12JCQNJC06900;天津市卫生局科技基金项目编号2011KZ109资助@@@@This work was supported by The National Natural Science Foundation of China81101915;The Project of Tianjin Applied Basic and Cutting-edge Technological Research12JCQNJC06900;The Tianjin Municipal Health Bureau Scientific and Technological Fund2011KZ109