Funding for this research was provided by:
Sichuan Science and Technology Department (2016Jy0156)
Text and Data Mining valid from 2020-02-21
Received: 28 November 2019
Accepted: 11 February 2020
First Online: 21 February 2020
Ethics approval and consent to participate
: Not involved into ethics.
: All authors have contributed to this study and approve its submission.
: The authors declare that they have no competing interests.