As a novel fluorescent nanomaterial,quantum dots (QDs) have a prospect for wide application. However , the adverse effects of QDs have become a concern among and more researchers. The toxic actions of QDs in vivo are closely associated with the biotransport and bio?transformation of QDs,which can be affected by the exposure pathways,exposure dose,surface modification and the particle size. Among them,the exposure pathways can affect the absorption and distribution of QDs in vivo,the exposure dose can affect the metabolism and excretion,thus influencing the distribution of QDs in vivo ,the surface modification can affect the distribution ,metabolism and excretion of QDs in vivo,the particle size can affect the absorption,distribution and excretion of QDs in vivo,and larger QDs are more likely to remain in the body and difficult to remove. QDs can enter the body through the circulatory system,get accumulated and degraded in the liver,kidney and other organs. The degraded products can be excerted through excrement and urine under the metabolism in the liver,spleen and kidneys. In addition,QDs can interact with biological macromolecules in the body,causing DNA damage,affecting the function and gene expression level of the liver,kidney,nervous system and other organs,and resulting in pathological and functional damage to tissues and organs.

Objective: To study the correlation between electronic screen use and myopia among primary and secondary school students in six provinces and cities in China, in order to provide a scientific basis for comprehensive prevention and control of myopia. Methods: From November 2020 to June 2022, a total of 16 557 primary and secondary school students from six provinces and cities in China (Beijing City, Liaoning Province, Zhejiang Province, Henan Province, Shaanxi Province, Chongqing City) were selected by stratified cluster random sampling and probability smampling methods, and a questionnaire prepared by Beijing Center for Disease Control and Prevention was used to investigate their electronic screen use. According to Screening Criteria for Myopia in Children and Adolescents, 0.5% mass concentration of compound topicamide eye drops was used to paralyze the ciliary muscle and undergo slit lamp optometry. Chisquare test was used to compare the differences between groups, and binary Logistic regression was used to analyze the association between electronic screen use and myopia. Results: About 58.3% of primary and secondary school students used electronic screens for more than two hours a day on average, and 63.4% of primary and secondary school students used continuously electronic products for more than 15 minutes at a time for nonstudy purposes. After adjusting for confounding factors, parents unrestricted use of electronic screen time and electronic screen time ≥2 h/d were positively correlated with myopia (OR=1.27, 1.13, P<0.05). Gender stratified analysis showed that boys who used electronic screen time ≥2 h/d had a higher risk of myopia (OR=1.15, P<0.05). The results of grade stratification analysis showed that parents unrestricted electronic screen use time and electronic screen time ≥2 h/d were positively correlated with myopia in the lower grade of primary school students (OR=1.34, 1.18, P<0.05). Among the higher grade of primary school students, continuous use of electronic screens for nonstudy purposes for more than 15 minutes at one time was positively correlated with myopia (OR=1.18, P<0.05). There was a multiplicative interaction between total screen time and one continuous screen time (OR=1.04, P<0.05). Conclusions Primary and secondary students in six provinces and cities in China reports excessive electronic screen usage which is associated with myopia. Schools and parents should jointly limit the use of electronic screen among primary and secondary students to reduce the occurrence of myopia.

Objective: To analyze the current status and related factors of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing, so as to provide a basis for comprehensive public health interventions for common diseases. Methods: Through stratified cluster random sampling in October 2022, a total of 11 262 junior high school, senior high school, and vocational high school students in 16 districts of Beijing were surveyed with self administered questionnaires, physical examinations and visual acuity examinations. The χ 2 test and binary Logistic regression model were used to analyze group differences in the comorbidity of myopia, obesity and depression symptoms and factors influencing the comorbidity. Stratified analysis was applied to analyze the associations between health risk behaviors and the comorbidity. Results: The detection rate of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing was 3.35%, the comorbidity rate among vocational high school students (4.61%) was higher than that in junior high school students (2.80%) and senior high school students (3.41%). The comorbidity rate was higher among students in suburban areas (3.66%) than that in urban areas (2.92%), and the differences was statistically significant ( χ 2=15.02, 4.63, P <0.05). Binary Logistic regression analyses indicated that middle school students with poor dietary behaviors ( OR =1.59) and excessive screen time ( OR =1.70) were associated with elevated risk of comorbidity of myopia, obesity, and depression symptoms. Both boys and girls with poor dietary behaviors ( OR =1.63, 1.69) and excessive screen time ( OR =1.45, 2.23) had elevated likelihood of comorbidity of myopia, obesity and depression symptoms. Students in junior high school and senior high school with poor dietary behaviors ( OR =2.16, 1.47) and excessive screen time ( OR =2.20, 1.63 ) had elevated likelihood of comorbidity of myopia, obesity, and depression symptoms ( P <0.05). Conclusions The current status of comorbidity of myopia, obesity, and depression symptoms among middle school students in Beijing is concerning. Schools and parents should work together to guide students to develop healthy behaviors such as balanced diet and moderate video, in order to achieve the goal of controlling myopia, obesity and depression symptoms.

Objective: To investigate the comorbidity of screening myopia and scoliosis among primary and secondary school students in Beijing from 2019 to 2022 and its influencing factors, in order to provide new ideas for comprehensive prevention and control of myopia and scoliosis in children and adolescents. Methods: From 2019 to 2022, 34 923, 34 321, 36 008 and 35 598 primary and secondary school students in Beijing were selected by stratified cluster random sampling method, and visual acuity examination, scoliosis examination and questionnaire survey were conducted on them. Chisquare test was used to analyze the intergroup differences between screening myopia and scoliosis among primary and secondary school students, and the correlation factors between screening myopia and scoliosis were analyzed by multivariate Logistic regression. Results: From 2019 to 2022, the prevalence of screening myopia increased by year,while scoliosis decreased by year, and the comorbidity rate in 2022 (0.69%) decreased by 1.62% compared with 2019 (2.31%). In 2022, screening myopia with scoliosis rates (0.98%) than urban suburbs (0.50%), high school students (1.65%) >professional high school students (1.21%) >junior middle school students (0.76%) >primary school students (0.22%) (χ2=28.97, 153.55, P<0.01). The results of multivariate Logistic analysis found that insufficient sleep time and parents did not limit the use of electronic screen time were the risk factors for screening myopia and scoliosis [OR(95%CI)=1.59(1.20-2.12), 1.34(1.02-1.76), P<0.05]. Teachers often or always remind that reading and writing posture and one hour or more of moderateintensity physical activity every day were protective factors for screening myopia and scoliosis [OR(95%CI)=0.70(0.52-0.96), 0.56(0.34-0.92), P<0.05]. Conclusions The comorbidity of acadmic screening myopia and scdiosis is not optimistic in Beijing. Attention should be paid to the reading and writing posture and related behavioral habits of children and adolescents, and ensure that children in each school section have sufficient sleep time, so as to prevent the occurrence and development of screening myopia and scoliosis.

Severe muscle injury is hard to heal and always results in a poor prognosis. Recent studies found that extracellular vesicle-based therapy has promising prospects for regeneration medicine, however, whether extracellular vesicles have therapeutic effects on severe muscle injury is still unknown. Herein, we extracted apoptotic extracellular vesicles derived from mesenchymal stem cells (MSCs-ApoEVs) to treat cardiotoxin induced tibialis anterior (TA) injury and found that MSCs-ApoEVs promoted muscles regeneration and increased the proportion of multinucleated cells. Besides that, we also found that apoptosis was synchronized during myoblasts fusion and MSCs-ApoEVs promoted the apoptosis ratio as well as the fusion index of myoblasts. Furthermore, we revealed that MSCs-ApoEVs increased the relative level of creatine during myoblasts fusion, which was released via activated Pannexin 1 channel. Moreover, we also found that activated Pannexin 1 channel was highly expressed on the membrane of myoblasts-derived ApoEVs (Myo-ApoEVs) instead of apoptotic myoblasts, and creatine was the pivotal metabolite involved in myoblasts fusion. Collectively, our findings firstly revealed that MSCs-ApoEVs can promote muscle regeneration and elucidated that the new function of ApoEVs as passing inter-cell messages through releasing metabolites from activated Pannexin 1 channel, which will provide new evidence for extracellular vesicles-based therapy as well as improving the understanding of new functions of extracellular vesicles.
Creatine/metabolism* ; Extracellular Vesicles ; Muscle, Skeletal/metabolism* ; Myoblasts/metabolism* ; Regeneration ; Connexins/metabolism*