Funding for this research was provided by:
Ministry of Science and Technology of the People's Republic of China (2016YFC0105207)
Received: 30 September 2019
Accepted: 26 November 2019
First Online: 16 December 2019
Ethics approval and consent to participate
: All volunteers received information concerning their participation in the study and gave written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.