Funding for this research was provided by:
National Natural Science Foundation of China (No. 21877078)
Text and Data Mining valid from 2019-05-17
Received: 10 January 2019
Revised: 26 April 2019
Accepted: 29 April 2019
First Online: 17 May 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.