Funding for this research was provided by:
National Natural Science Foundation of China (81570823)
Text and Data Mining valid from 2019-06-25
Received: 23 October 2018
Accepted: 13 June 2019
First Online: 25 June 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Ethics Committee of Ethics Committee of Tangdu Hospital of the Fourth Military Medical University, Xi’an, China (TDLL 201506–05). Written informed consent was obtained from all participants prior to study enrolment.
: Not applicable.
: The authors declare that they have no competing interests.