Funding for this research was provided by:
National Natural Science Foundation of China (81670067)
Social Development Funds of Jiangsu Province (BE2017691)
Social Development Funds of Yangzhou (YZ2017086)
Text and Data Mining valid from 2019-12-01
Received: 30 June 2019
Accepted: 12 November 2019
First Online: 5 December 2019
Ethics approval and consent to participate
: Not applicable.
: All authors have agreed to the publication of this manuscript.
: The authors declare that they have no competing interests.