Funding for this research was provided by:
National Natural Science Foundation of China (51702273)
“Huxiang Young Talents Plan” Support Project of Hunan Province (2018RS3087)
Science and Technology Innovation Project of Hunan Province (2017XK2048)
Received: 27 April 2019
Accepted: 24 June 2019
First Online: 26 July 2019
: The authors declare that they have no competing interests.