Funding for this research was provided by:
National Natural Science Foundation of China (81600864)
Scientific Research Foundation for Young Teachers of Sichuan University (2017SCU11007)
Article History
Received: 17 December 2018
Accepted: 18 April 2019
First Online: 1 May 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.
: For this type of study, formal consent is not required.