Funding for this research was provided by:
National Natural Science Foundation of China (U1730136)
the Fundamental Research Funds for the Central Universities (2017XKQY062)
Text and Data Mining valid from 2019-07-16
Received: 22 March 2019
Accepted: 19 June 2019
First Online: 16 July 2019
Ethics Approval and Consent to Participate
: Not applicable.
: The authors declare that they have no competing interests.