Funding for this research was provided by:
National Natural Science Foundation of China (61601352, 61105066, 61671356, 61704127, 61571346)
Fundamental Research Funds for the Central Universities (JB141305)
Scientific Research Program Funded by Shaanxi Provincial Education Department (17JK0989)
Text and Data Mining valid from 2018-05-02
First Online: 2 May 2018
Compliance with ethical standards
: The authors declare that there is no conflict of interests regarding the publication of this article.