国家自然科学基金资助项目No.81373403,广西硕士研究生科研创新资助项目No.YCSZ2013031,广西卫生厅课题资助项目No.Z202066,广西医科大学青年基金课题资助No.02604001020.Project supported by the National Natural Science Foundation of China No.81373403,the Graduate Research and Innovation Project of Guangxi Province No.YCSZ2013031,the Research Foundation from the Regional Health Department of Guangxi Province No.Z202066,and the Youth Foundation of Guangxi Medical University No.02604001020