Funding for this research was provided by:
National Natural Science Foundation of China (81102145, 81874268, 81573163)
Text and Data Mining valid from 2019-04-24
Received: 9 March 2018
Accepted: 9 April 2019
First Online: 24 April 2019
Ethics approval and consent to participate
: The study was approved by the Biomedicine Ethical Committee of Anhui Medical University. The participants were fully informed of the purpose of the study and were invited to participate voluntarily. Written informed consent was obtained from the school, each participating student and one of the student’s parents.
: Not applicable.
: The authors have no conflict of interests to declare.
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