Funding for this research was provided by:
National Natural Science Foundation of China (31560027)
Natural Science Foundation of Guangxi Province (2017GXNSFAA198297)
Article History
Received: 17 September 2019
Accepted: 4 February 2020
First Online: 6 March 2020
Ethical approval and consent to participate
: Not applicable.
: All authors agreed to publish this article.
: The authors declare that they have no competing interests.