Funding for this research was provided by:
National Natural Science Foundation of China (21575066)
Science and Technology Department of Henan Province (192102310033)
Text and Data Mining valid from 2020-02-11
Received: 12 November 2019
Revised: 15 December 2019
Accepted: 7 January 2020
First Online: 11 February 2020
Compliance with ethical standards
: The authors have declared no conflict of interest.
: This article does not contain any studies with human or animal subjects.