Funding for this research was provided by:
Fundamental Research Funds for the Central Universities (DC201502010305)
Liaoning Provincial Natural Science Foundation of China (201602196)
Text and Data Mining valid from 2018-06-11
Received: 9 March 2018
Accepted: 30 May 2018
First Online: 11 June 2018
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.