Funding for this research was provided by:
Natural Science Foundation of Hunan Province (2018JJ3191)
Text and Data Mining valid from 2019-04-03
Received: 24 November 2018
Accepted: 15 March 2019
First Online: 3 April 2019
Compliance with ethical standards
: All 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.