Funding for this research was provided by:
Science and Technology Plan Project of Sichuan Province (2016GZ0092)
Article History
Received: 4 November 2018
Accepted: 3 December 2018
First Online: 13 December 2018
Compliance with ethical standards
:
: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
: This article does not contain any studies with human participants performed by any of the authors.