Funding for this research was provided by:
National Natural Science Foundation of China (81472962)
The Guangxi Science Fund for Distinguished Young Scholars (2012GXNSFFA060009)
The Fok Ying Tung Education Foundation (141118)
Text and Data Mining valid from 2018-08-01
Received: 28 March 2018
Accepted: 24 July 2018
First Online: 1 August 2018
Ethics approval and consent to participate
: The Medical Ethics Committee of Guangxi Medical University approved this study. All participants were fully informed about the study purpose and methods and provided written consent to participate.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.