Funding for this research was provided by:
National Natural Science Foundation of China (61836014, 11672150)
Text and Data Mining valid from 2020-02-12
Received: 13 December 2019
Accepted: 3 February 2020
First Online: 12 February 2020
Compliance with ethical standards
: The authors declare that they have no conflict of interest with regard to the publication of this manuscript.