Funding for this research was provided by:
Sichuan Province Science and Technology Support Program (2017SZ0062)
Graduate Student's Research and Innovation Fund of Sichuan University (2018YJSY098)
Text and Data Mining valid from 2020-03-04
Received: 10 October 2019
Accepted: 14 February 2020
First Online: 4 March 2020
Ethics approval and consent to participate
: The ethics approval of this study was approved by the Medical Ethics Committee of Sichuan University. Legal guardians were contacted to provide written consent on behalf of the patients to participate in the study.
: Not applicable.
: The authors declare that they have no competing interests.