Funding for this research was provided by:
Guangdong Science and Technology Department (No. 2016A020216026)
Received: 11 June 2018
Accepted: 16 July 2019
First Online: 24 July 2019
Ethics approval and consent to participate
: Not applicable. The Ethics Committee of Shantou University Medical College declared that this study did not require ethics approval.
: Not applicable.
: The authors declare that they have no competing interests.