Funding for this research was provided by:
the National Natural Science Foundation of China (61563013,61663006, 61505037)
the Natural Science Foundation of Guangxi (2018GXNSFAA138095)
the National Natural Science Foundation (61473338)
Natural Science Foundation of Guangxi (2015GXNSFBA139259)
Article History
Received: 5 January 2018
Accepted: 4 October 2018
First Online: 29 October 2018
Competing interests
: The authors declare that they have no competing interests.