Funding for this research was provided by:
National Natural Science Foundation of China (815703960, 81670402)
Text and Data Mining valid from 2018-08-27
Received: 26 March 2018
Revised: 25 May 2018
Accepted: 1 June 2018
First Online: 27 August 2018
Compliance with ethical guidelines
: S.-y. Liang, Y.-l. Zhou, M.-q. Shu, and S. Lin declare that they have no competing interests.
: This article does not contain any studies with human participants or animals performed by any of the authors.