Funding for this research was provided by:
National Natural Science Foundation of China (81371071, 81974141)
Natural Science Foundation of Guangdong Province (2017A030313817)
Text and Data Mining valid from 2019-11-28
Accepted: 21 November 2019
First Online: 28 November 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.