Funding for this research was provided by:
National Natural Science Foundation of China (51675321)
Article History
Received: 3 August 2018
Revised: 10 December 2018
Accepted: 18 December 2018
First Online: 4 January 2019
Compliance with ethical standards
:
: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
: All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments. For this type of study, formal consent is not required.