Funding for this research was provided by:
National Natural Science Foundation of China (31571252)
National Science Foundation (IOS-1340001)
Guangdong Innovation Research Team Fund (2014ZT05S078)
Natural Science Startup Foundation of Shenzhen University (2016101)
Article History
Received: 31 October 2017
Accepted: 15 December 2017
First Online: 9 January 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.