The proliferation of short video apps has brought to the forefront the issue of adolescent addiction, a challenge that resonates across Chinese society. Despite growing attention, a comprehensive understanding of the factors propelling addiction at various adolescent stages and its impact on academic performance remains scarce. This study aims to fill this void by identifying key growth stages and crafting targeted intervention strategies. Our investigation engaged 1,896 Chinese students, averaging 15 years old, at pivotal educational junctures. Employing a mixed-method approach, we utilized interviews and surveys, enhanced by fixed effects models and instrumental variables, to discern patterns in short video addiction. The study revealed stage-specific catalysts for addiction: social identity in junior high, academic stress in senior high, and personality traits in university students. A concerning trend was the double and triple rate of severe addiction among senior high students compared to their junior high and university counterparts, respectively, with a peak of 52.7% mild addiction in university. Our predictive model provides a holistic perspective on the drivers of addiction. This groundbreaking analysis delineates the complex interplay of adolescent short video addiction in China, under-scoring its profound implications for academic progression in senior high. The findings under-score the urgent need for tailored interventions to counteract the adverse effects of addiction.

The precise editing of genes mediated by CRISPR-Cas9 necessitates the application of donor DNA with appropriate lengths of homologous arms and fragment sizes. Our previous development, SSB/CRISPR-Cas9, has demonstrated high efficiency in homologous recombination and non-homologous end joining gene editing within bacteria. In this study, we optimized the lengths and sizes of homologous arms of the donor DNA within this system. Two sets of donor DNA constructs were generated: one set comprised donors with only 10–100 bp homologous arms, while the other set included donors with homologous arms ranging from 10–100 bp, between which was a tetracycline resistance expression cassette (1439 bp). These donor constructs were transformed into Escherichia coli MG1655 cells alongside pCas-SSB/pTargetF-lacZ. Notably, when the homologous arms ranged from 10 to 70 bp, the transformation efficiency of non-selectable donors was significantly higher than that of selectable donors. However, within the range of 10–100 bp homologous arm lengths, the homologous recombination rate of selectable donors was significantly higher than that of non-selectable donors, with the gap narrowing as the homologous arm length increased. For selectable donor DNA with homologous arm lengths of 10–60 bp, the homologous recombination rate increased linearly, reaching a plateau when the homologous arm length was between 60–100 bp. Conversely, for non-selectable donor DNA, the homologous recombination rate increased linearly with homologous arm lengths of 10–90 bp, plateauing at 90–100 bp. Editing two loci simultaneously with 100 bp homologous arms, whether selectable or non-selectable, showed no difference in transformation or homologous recombination rates. Editing three loci simultaneously with 100 bp non-selectable homologous arms resulted in a 45% homologous recombination rate. These results suggest that efficient homologous recombination gene editing mediated by SSB/CRISPR-Cas9 can be achieved using donor DNA with 90–100 bp non-selectable homologous arms or 60–100 bp selectable homologous arms.

Single-stranded DNA-binding proteins (SSBs) are essential for all living organisms. Whether SSBs can repair DNA double-strand breaks (DSBs) and improve the efficiency of CRISPR/Cas9-mediated genome editing has not been determined. Here, based on a pCas/pTargetF system, we constructed pCas-SSB and pCas-T4L by replacing the λ-Red recombinases with Escherichia coli SSB and phage T4 DNA ligase in pCas, respectively. Inactivation of the E. coli lacZ gene with homologous donor dsDNA increased the gene editing efficiency of pCas-SSB/pTargetF by 21.4% compared to pCas/pTargetF. Inactivation of the E. coli lacZ gene via NHEJ increased the gene editing efficiency of pCas-SSB/pTargetF by 33.2% compared to pCas-T4L/pTargetF. Furthermore, the gene-editing efficiency of pCas-SSB/pTargetF in E. coli (ΔrecA, ΔrecBCD, ΔSSB) with or without donor dsDNA did not differ. Additionally, pCas-SSB/pTargetF with donor dsDNA successfully deleted the wp116 gene in Pseudomonas sp. UW4. These results demonstrate that E. coli SSB repairs DSBs caused by CRISPR/Cas9 and effectively improves CRISPR/Cas9 genome editing in E. coli and Pseudomonas.

Foxtail millet (Setaria italica), a significant C4 model crop known for its exceptional photosynthetic efficiency and robust environmental adaptability, serves as an excellent model for investigating C4 photosynthesis and crop stress resilience. When subjected to abiotic stress, foxtail millet employs a sophisticated signal transduction network to regulate its physiological processes, ensuring sustained high photosynthetic efficiency and normal growth. The mitogen-activated protein kinase (MAPK) family plays a key role in plant growth, development, and stress response. Here, we identified and named a MAPK in S. italica as SiMPK6. Fluorescence quantitative PCR analysis revealed that SiMPK6 is mainly expressed in the leaves during the early shooting stage, with induction under various abiotic stresses such as low temperature, high osmotic pressure, high salt, high temperature, and high light. Overexpressing the SiMPK6 in Arabidopsis thaliana mitigated damage to photosystem II induced by stress, underscoring the gene’s crucial role in foxtail millet’s stress signal transduction and maintenance of high photosynthetic efficiency.

This study develops a “Bio-Social-Cognitive Dynamic Interaction Model” to explore seasonal mental health risks in Chinese adolescents. Using data from cross-sectional surveys (N = 6,121), longitudinal tracking (N = 1,000), and RCTs (N = 200), we assess mental health via PHQ-9, GAD-7, and SADQ scales. We analyze multidimensional indicators (melatonin, vitamin D, academic stress) via SEM and ARIMA, considering school stage and gender. Results show winter has the highest depression and anxiety scores (PHQ-9: M = 14.5 ± 4.8), linked to vitamin D deficiency (β=-0.25, p < 0.001) and social stress. Spring academic stress affects emotional stability via melatonin and sleep issues (β = 0.15, p = 0.002), while summer anxiety is tied to social overload and body dissatisfaction (β = 0.10, p = 0.04). Winter light therapy increases vitamin D (Δ = 8.2 ng/mL, p < 0.001) and reduces depression (ΔPHQ-9=-3.1, p = 0.005). We recommend seasonal interventions like winter light therapy, flexible spring exams, and summer social media literacy programs, and emphasize year-round monitoring for effective risk mitigation.