Background As internet use becomes more widespread, the screen time (ST) of elementary school students increases yearly. It is known that longer durations of ST can affect obesity, physical activity, dry eye disease, and learning ability. However, the effects of ST just before bedtime have not been clarified. Therefore, we examined ST duration and timing effects on elementary school children. Methods We conducted a survey of 7419 elementary school students in Tokyo, Japan using a questionnaire on food education. ST duration and timing (just before bedtime) served as the explanatory variables, and the relationship between obesity, physical activity, dry eyes, and learning ability was analyzed using logistic regression analysis. Gender, school year, height, and weight were considered confounding factors. First, we examined whether ST duration and timing were related to each objective variable, using a univariate model to examine all variables. Thereafter, we performed multivariate logistic regression analyses for all variables showing a significant difference in the univariate models. Results A significant association was observed between ST duration and obesity, physical activity, and academic performance, indicating that a longer ST duration may lead to obesity, decreased physical activity, and decreased academic performance. ST timing was associated with obesity, dry eyes, and academic performance, and ST immediately before bedtime contributed to obesity, dry eyes, and reduced academic performance. Furthermore, the results of investigating the combined effect of ST duration and timing (immediately before bedtime) on these factors revealed that ST timing has a greater effect on dry eyes, and ST duration has a greater effect on academic performance. Conclusion Our findings indicate that ST in school children is related to obesity, physical activity, dry eyes, and learning ability, and they suggest that not only the duration but also the timing of ST is important.

The circadian clock maintains our health by controlling physiological functions. Social jet lag is one factor that can disrupt the body clock. This is caused by the difference in sleeping hours between weekdays when we live according to social time and holidays when we live according to our body clock. The body clock can be altered by exercise, nutrition, and stress, and several studies have reported that these factors can be used to improve a disturbed body clock. Here we focused on exercise and examined whether continuous wheel-running could improve the disordered body clock in a mouse model that mimics social jet lag. The results showed that the wheel-running exercise group showed faster synchronization of the onset of activities on weekdays which had been delayed by social jet lag and the results were even more pronounced in the high-fat diet feeding condition. Also, when the expression rhythms of the clock genes were examined, they experienced a sudden time shift in the advance light condition or social jet lag condition, it was found that the wheel-running group had a higher ability to adapt to the advance direction. Thus, it is possible that the effective inclusion of exercise in human, especially those who eat high-fat foods, life can improve the disordered body clock in terms of social jet lag.

A calf of two weeks old showed purple spots and hemorrhages in several parts of the skin. At necropsy, petechiae and ecchymosis were observed in the skin, subcutaneous tissue and serosal surface of visceral organs. Hematologically, no thrombocytes could be detected in blood smears and clot retraction did not occur. Light microscopy revealed multiple hemorrhages in the subcutis, submucosa and serosa of the intestinal tract, and in the other internal organs. In the bone marrow, megakaryocytes appeared normal but slightly increased in number, whereas thrombocytes were decreased. The number of thrombocytes markedly decreased, when blood samples from normal calves were mixed with blood plasma of the diseased calf or when the rabbits were injected intravenously with the serum from the diseased calf. In the former case, aggregates of thrombocytes were frequently seen. It suggested the presence of a platelet agglutinating factor in the patient plasma. Based on the data collected, the present case was diagnosed as thrombocytopenic purpura.

Background: As internet use becomes more widespread, the screen time (ST) of elementary school students increases yearly. It is known that longer durations of ST can affect obesity, physical activity, dry eye disease, and learning ability. However, the effects of ST just before bedtime have not been clarified. Therefore, we examined ST duration and timing effects on elementary school children. Methods: We conducted a survey of 7,419 elementary school students in Tokyo, Japan using a questionnaire on food education. ST duration and timing (just before bedtime) served as the explanatory variables, and the relationship between obesity, physical activity, dry eyes, and learning ability was analyzed using logistic regression analysis. Gender, school year, height, and weight were considered confounding factors. First, we examined whether ST duration and timing were related to each objective variable, using a univariate model to examine all variables. Thereafter, we performed multivariate logistic regression analyses for all variables showing a significant difference in the univariate models.Results: The results showed that the relationship between the ST duration and obesity, physical activity, and learning ability was statistically significant. The relationship between ST timing and obesity, dry eyes, and learning ability was also statistically significant. Therefore, ST timing has a greater effect on dry eyes, and ST duration has a greater effect on academic performance. Conclusion: Our findings indicate that ST in school children is related to obesity, physical activity, dry eyes, and learning ability, and they suggest that not only the duration but also the timing of ST is important.