Funding for this research was provided by:
National Natural Science Foundation of China (31970012, 31570014)
Youth Innovation Promotion Association of the Chinese Academy of Sciences (2017240)
Text and Data Mining valid from 2020-01-09
Received: 30 August 2019
Accepted: 21 December 2019
First Online: 9 January 2020
: The authors declare no competing interests.