Funding for this research was provided by:
National Natural Science Foundation of China (Grant No. 81573678)
Natural Science Foundation of Guangdong Province (Grant No. 2015A030313584)
Article History
Received: 20 October 2018
Accepted: 5 January 2019
First Online: 1 February 2019
Compliance with ethical standards
: We declare that we have no competing interests. And informed consent was obtained from all individual participants included in the study.