Funding for this research was provided by:
National Natural Science Foundation of China (31270215)
Article History
Received: 21 August 2018
Accepted: 7 January 2019
First Online: 12 January 2019
Compliance with Ethical Standards
:
: JZ has received a research grant from the NSF China, but declares no conflict of interest. SKJ declares that he has no conflict of interest. CL declares that he has no conflict of interest. KH declares that he has no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: Not applicable.