Li, Hongyu
Nan, Li
Li, Jun
Song, Hui
Funding for this research was provided by:
Natural Science Foundation of Tianjin City (18JCZDJC36400)
Tianjin Municipal Health Bureau (2014KY37)
Article History
Received: 31 October 2019
Accepted: 6 April 2020
First Online: 1 May 2020
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.