Funding for this research was provided by:
National Natural Science Foundation of China (60973137, 61402210)
Program for New Century Excellent Talents in University (NCET-12-0250)
Strategic Priority Research Program of the Chinese Academy of Sciences (XDA03030100)
Text and Data Mining valid from 2017-09-25
First Online: 25 September 2017
Compliance with ethical standards
: All authors declare that they have no conflicts of interest regarding the publication of this manuscript.