Funding for this research was provided by:
Strategic Priority Research Program (B) of Chinese Academy of Sciences (XDB18000000)
Major Program of National Natural Science Foundation of China (41590854)
Text and Data Mining valid from 2019-07-30
Received: 27 February 2019
Accepted: 21 July 2019
First Online: 30 July 2019
: The authors declare that they have no competing interests.