Funding for this research was provided by:
National Natural Science Foundation of China (31100017)
Text and Data Mining valid from 2019-03-11
Received: 24 October 2018
Revised: 4 February 2019
Accepted: 12 February 2019
First Online: 11 March 2019
Compliance with ethical standards
: The authors declare that they have no conflicts of interest.
: This article does not contain any studies performed with human participants or with animals by the author.