Funding for this research was provided by:
National Natural Science Foundation of China (31372476, 31572562)
Article History
Received: 10 October 2017
Accepted: 9 January 2018
First Online: 18 January 2018
Compliance with Ethical Standards
:
: Jiufeng Li declares that he has no conflict of interest. Xuqin Song declares that she has no conflict of interest. Meiyu Zhang declares that she has no conflict of interest. Erfen Li declares that she has no conflict of interest. Limin He declares that he has no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of authors.
: Not applicable.