Funding for this research was provided by:
National Natural Science Foundation of China (21205108)
Foundation for University Key Teacher by Henan Province (2017GGJS007)
Key Scientific Research Project in Universities of Henan Province (19A150048)
Article History
Received: 11 October 2018
Accepted: 14 December 2018
First Online: 9 January 2019
Compliance with ethical standards
: The authors declare that they have no competing interests.