Funding for this research was provided by:
National Natural Science Foundation of China (81600714)
National Natural Science Foundation of China (81402247)
Natural Science Foundation of Hunan Province (2017JJ3451)
Hunan Provincial Science and Technology Department (2015TP2007)
Text and Data Mining valid from 2018-04-13
First Online: 13 April 2018
Ethics approval and consent to participate
: Not applicable.
: All authors have given consent for publication.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.