Funding for this research was provided by:
National Natural Science Foundation of China (11532016;91530325)
Text and Data Mining valid from 2019-09-17
Version of Record valid from 2019-09-17
Article History
Received: 31 May 2019
Accepted: 21 August 2019
First Online: 17 September 2019
Competing interests
: The authors declare that they have no competing interests.