Funding for this research was provided by:
National Natural Science Foundation of China (Grant No. 81670204, Grant No. 81171839)
Funding of Xiamen University (Grant No. 20720170106)
Text and Data Mining valid from 2019-02-12
First Online: 12 February 2019
Compliance with Ethical Standards
: The authors declare that there is no duality of interest associated with this manuscript.