Funding for this research was provided by:
National Natural Science Foundation of China (41671439)
Innovation Team Support Program of Liaoning Higher Education Department (LT2017013)
Text and Data Mining valid from 2019-10-14
Received: 4 April 2019
Accepted: 4 September 2019
First Online: 14 October 2019
: The authors declare that they have no competing interests.