Funding for this research was provided by:
National Natural Science Foundation of China (No.81371197)
Text and Data Mining valid from 2018-11-10
Received: 16 January 2018
Accepted: 25 October 2018
First Online: 10 November 2018
Compliance with ethical standards
: The authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.