Article History
Received: 23 November 2020
Accepted: 18 March 2021
First Online: 10 April 2021
Compliance with ethical standards
:
: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the Shandong Provincial Hospital Affiliated to Shandong First Medical University.
: Informed consent was obtained from all the children' parents for both participation and publication of the study.