Funding for this research was provided by:
Science and Technology Bureau of Yibin City (No. 2015 SF 027)
Article History
Received: 27 December 2019
Accepted: 22 May 2020
First Online: 29 June 2020
Compliance with ethical standards
:
: The authors declare no competing interest pertaining to the publication of this paper.
: All procedures in the present study, which involves human participants, were in strict accordance with the ethical standards of the 1964 Helsinki declaration and its later amendments. Written consent was obtained from all of the subjects.