Funding for this research was provided by:
China Postdoctoral Science Foundation (2017M623371)
National Natural Science Foundation of China (81270102, 81500308, 81770243, 81470248)
grant from Shaanxi Province (2016KTCL03-11)
Text and Data Mining valid from 2018-08-28
Received: 1 May 2018
Accepted: 19 July 2018
First Online: 28 August 2018
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of Fourth Military Medical University.
: All authors have approved the final manuscript for publication.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.