Funding for this research was provided by:
National Natural Science Foundation of China (81771781, U1804281, 81602024)
Text and Data Mining valid from 2019-08-08
Received: 23 June 2019
Accepted: 31 July 2019
First Online: 8 August 2019
Ethics approval and consent to participate
: The research protocol was reviewed and approved by the Ethics Committee of Zhengzhou University (Ethical approval number: Science-2010-LW-1213), and informed consent was obtained from all participants included in the study, in agreement with institutional guidelines.
: Not applicable.
: The authors declare that they have no competing interests.