Funding for this research was provided by:
Natural Science Foundation of China (31272090)
Natural Science Foundation of Chongqing (cstc 2018jcyjAX0554)
the Fundamental Research Funds for the Central Universities (106112017CDJQJ298831)
Article History
Received: 30 October 2018
Revised: 27 November 2018
Accepted: 4 December 2018
First Online: 10 January 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 performed by any of the authors.