A Longitudinal Study of Insomnia, Daytime Sleepiness, and Academic Performance in Chinese Adolescents.

BACKGROUND: Longitudinal data on the associations between sleep disturbances, daytime sleepiness, and daily functioning are limited in the general adolescent population. This study examined the cross-sectional and longitudinal associations between insomnia, excessive daytime sleepiness (EDS), and subject-specific academic performance in a large sample of Chinese adolescents. METHOD: Data were derived from the Shandong Adolescent Behavior and Health Cohort (n = 7,072) study. A self-administered questionnaire was used to assess insomnia, EDS, academic performance (overall, Chinese, mathematics, and English), behavioral and emotional problems, and family demographics. The cross-sectional analysis was conducted with baseline data while the longitudinal analysis was conducted with both baseline and 1-year follow-up data. Logistic regression analyses and mediation models were performed to examine the associations between insomnia, EDS, and academic performance. RESULTS: Logistic regression analyses revealed that insomnia and EDS had significant cross-sectional associations with overall performance and mathematics performance after controlling for age, gender, ever smoking, ever alcohol drinking, frequent snore, sleep duration, chronic disease, anxious/depressive symptoms, parents' education, parents' occupation, and family economic status. Both insomnia (OR = 1.20, 95% CI: 1.00-1.45) and EDS (OR = 1.22, 95% CI: 1.03-1.45) at baseline were significantly associated with poor mathematics performance 1 year later. The effect of insomnia at baseline on poor academic performance 1 year later was mediated by EDS except for the Chinese subject after controlling for the covariates. CONCLUSIONS: Insomnia and daytime sleepiness are significantly associated with poor academic performance, particularly in mathematics. EDS mediates the association between insomnia and poor academic performance. Further research is warranted to investigate the effects of sleep disturbance and daytime sleepiness on the learning process and performance across academic subjects.

PDCD4-mediated downregulation of Listeria monocytogenes burden in macrophages.

INTRODUCTION: Macrophages are effector cells of the innate immune system and defend against invading pathogens. Previous reports have shown that infection with Listeria monocytogenes upregulates miR-21a expression in macrophages. AIM OF THE STUDY: We aimed to verify whether programmed cell death 4 (PDCD4) is involved in the high bacterial burden observed in macrophages during late-stage L. monocytogenes infections. MATERIAL AND METHODS: We examined the expression of miR-21a and its known target PDCD4 in macrophages after L. monocytogenes infection. The macrophages' uptake ability of L. monocytogenes was measured using FluoSpheres Carboxylate-modified microspheres. We depleted PDCD4 by transfecting macrophages with siPDCD4. RESULTS: In macrophages, PDCD4 protein was downregulated 5 h, but not 2 h, after L. monocytogenes infection. Our results validated the hypothesis that PDCD4-depleted macrophages present a higher L. monocytogenes burden. Moreover, we found that the activation of c-Jun and STAT3 accompanied PDCD4 downregulation. CONCLUSIONS: Our results showed that PDCD4 mediated the suppression of L. monocytogenes infection in macrophages via c-Jun/STAT3 signalling activation.

Prolonged Mobile Phone Use Is Associated with Poor Academic Performance in Adolescents.

Prolonged mobile phone use (MPU) is prevalent in adolescents. This study examined the associations between prolonged MPU and academic performance in Chinese adolescents. Participants were 11,831 adolescents who participated in the Shandong Adolescent Behavior and Health Cohort in 2015. We used a self-administered questionnaire to collect data on demographics, weekday and weekend MPU, sleep duration, insomnia, depression, and academic performance. We obtained a subsample's year-end achievement test scores for Chinese, Mathematics, and English, 3 months after baseline survey (n = 856). Results showed that with prolonged MPU from ≥1 hour/day on weekdays and ≥2 hours/day on weekends, the prevalence of self-reported poor academic performance significantly increased, and the achievement test scores significantly decreased. After controlling for adolescent and family covariates, students who used mobile phone ≥2 hours/day on weekdays (OR = 2.12, 95% CI = 1.82-2.47) and ≥5 hours/day on weekends (OR = 1.50, 95% CI = 1.31-1.72) were significantly more likely to report poor overall academic performance and scored significantly lower on Mathematics and English compared with those who used mobile phone <1 hour/day on weekdays and <2 hours/day on weekends, respectively. The mediating effects of reduced sleep duration, insomnia, and depression on the association between prolonged MPU and academic performance was small. In conclusion, prolonged MPU is associated with poor academic performance as measured by self-reports and subject tests in Chinese adolescents. Our findings suggest that adolescents should be advised to limit the time of MPU to minimize its harmful effects on sleep, mental health, and academic performance.

[Effects of nitrogen addition on available nitrogen content and acidification in cold-temperate coniferous forest soil in the growing season].

Based on a low-level and multi-form N addition control experiment, this study took cold-temperate coniferous forest in Daxing'an Ling as the research object. After long-term and continuous nitrogen addition in situ, the available nitrogen (NH4(+) -N & NO3(-) -N) contents and pH values of the soil (0-10 cm) were measured in the early growing season (May) and the peak growing season (August) in 2010, 2012 and 2013. The results showed that, the available nitrogen in the early and peak growing seasons was mainly NH4(+) -N which accounted for over 96% of the inorganic nitrogen content, while the content of NO3(-) -N was very low. With the time extension of nitrogen addition, the effects of nitrogen addition on the NH4(+) -N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH4(+) -N content was mainly affected by the type of nitrogen addition. On the contrary, the NO3(-) -N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO3(-) -N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO3(-) -N. As time went on, the response of NH4(+) -N and NO3(-) -N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0 - 10 cm soil in this cold-temperate coniferous forest was obviously acidified.