Funding for this research was provided by:
National Natural Science Foundation of China (81441037)
Text and Data Mining valid from 2019-03-13
First Online: 13 March 2019
Compliance with Ethical Standards
: This study was approved by the Ethics Committee of Xuanwu Hospital, Capital Medical University, adhered to the tenets of the Declaration of Helsinki.
: The authors declare that they have no conflict of interest.
: InternalRef removed provided by the authors are available with the online version of this article.