Funding for this research was provided by:
National Natural Science Foundation of China (31961133006)
Text and Data Mining valid from 2019-07-11
Received: 4 May 2019
Accepted: 3 July 2019
First Online: 11 July 2019
Ethics approval and consent to participate
: All the authors have read and agreed the ethics for publishing the manuscript.
: The authors approved the consent for publishing the manuscript.
: The authors declare that they have no competing interests.