Funding for this research was provided by:
National Natural Science Foundation of China (71503139)
China Postdoctoral Science Foundation (2016M600400)
Natural Science Research of Jiangsu Higher Education Institutions of China (16KJB330002)
Philosophy and Social Science Research of Jiangsu Higher Education Institutions of China (2017SJB0267)
Received: 27 March 2018
Accepted: 26 November 2019
First Online: 5 December 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the Research Ethics Committee of Nanjing University (Nanjing, Jiangsu, China), and written informed consent was obtained from all individual participants included in the study. Parental consent was acquired if any participants were under 16. Throughout data analysis, no personal identifiers were recorded; instead identification code numbers were used.
: Not applicable.
: The authors declare that they have no competing interests.