Funding for this research was provided by:
National Natural Science Foundation of China (81873941, 81701922)
Article History
Received: 28 October 2019
Accepted: 25 December 2019
First Online: 9 January 2020
Compliance with Ethical Standards
:
: The authors declare that they have no conflicts of interest.
: All analyses were based on previous published studies, and thus, ethical approval is unnecessary.
: This study was based on previous published studies, so informed consent was unnecessary.