Supported by Beijing Natural Science Foundation (No. 7174298), Miaopu Project of Beijing Tiantan Hospital affiliated to Capital Medical University (No. 2014MP04) and the 51th lot General Financial Grant from the China Postdoctoral Science Foundation (No. 2012M510723),Conflict of Interest,All authors have no conflict of interest regarding this paper.,Author Contributions,Li KN and Wang Z designed the research. Li KN, Zhang YY, and Yu YN performed the research and analyzed data. Wu HL performed the text mining. Li KN drafted the manuscript. All authors gave final approval of the version to be published, and agree to be accountable for all aspects of the work.