AUTHOR=Xu Zhenguo , Niu Menghui , Du Wenxiu , Dang Tongtong TITLE=The effect of sleep quality on learning engagement of junior high school students: the moderating role of mental health JOURNAL=Frontiers in Psychology VOLUME=16 YEAR=2025 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2025.1476840 DOI=10.3389/fpsyg.2025.1476840 ISSN=1664-1078