Funding for this research was provided by:
Natural Science Foundation of Jilin Province (20180101101JC)
Finance Department Health Special Project of Jilin Province (3D518V613429)
Article History
Received: 24 November 2018
Accepted: 17 May 2019
First Online: 28 May 2019
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.