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This study aims to explore the relationship between locus of control, grit, self-esteem and mental health among college students. A questionnaire survey was used to conduct a study on the mental health of 923 E-learning college students from 10 universities in Guangxi, China. In this study, Pearson correlation analysis was used to test the correlation between the study variables, and Bootstrap was used to test the mediating effect and effect ratio of grit and self-esteem. The results show that, locus of control, grit, and self-esteem can predict the mental health of college students. Grit plays a mediating role between locus of control and mental health; self-esteem plays a mediating role between locus of control and mental health; grit and self-esteem have a chain mediating effect between locus of control and mental health. Specifically, internal locus of control can effectively prevent college students from mental health problems through the chain mediation effect of grit and self-esteem. Powerful others and opportunity as the external locus of control will not only reduce the grit and self-esteem of college students, but also lead to more psychological problems. These research results provide suggestions to the university management on how to manage the mental health of E-learning students, especially those with psychological problems.

Coproporphyrin III (CP III), a natural porphyrin derivative, has extensive applications in the biomedical and material industries. S. cerevisiae has previously been engineered to highly accumulate the CP III precursor 5-aminolevulinic acid (ALA) through the C4 pathway. In this study, a combination of cytoplasmic metabolic engineering and mitochondrial compartmentalization was used to enhance CP III production in S. cerevisiae. By integrating pathway genes into the chromosome, the CP III titer gradually increased to 32.5 ± 0.5 mg/L in shake flask cultivation. Nevertheless, increasing the copy number of pathway genes did not consistently enhance CP III synthesis. Hence, the partial synthesis pathway was compartmentalized in mitochondria to evaluate its effectiveness in increasing CP III production. Subsequently, by superimposing the mitochondrial compartmentalization strategy on cytoplasmic metabolic engineered strains, the CP III titer was increased to 64.3 ± 1.9 mg/L. Furthermore, augmenting antioxidant pathway genes to reduce reactive oxygen species (ROS) levels effectively improved the growth of engineered strains, resulting in a further increase in the CP III titer to 82.9 ± 1.4 mg/L. Fed-batch fermentations in a 5 L bioreactor achieved a titer of 402.8 ± 9.3 mg/L for CP III. This study provides a new perspective on engineered yeast for the microbial production of porphyrins.

Objective: The aim of this study was to investigate the value of genetic testing using exome sequencing (ES) in oligohydramnios pregnancies with or without other structural abnormalities. Materials and methods: A total of 110 singleton pregnancies complicated by oligohydramnios were enrolled, including 52 of isolated oligohydramnios and 58 of non-isolated oligohydramnios. All fetal samples were first tested by quantitative fluorescent polymerase chain reaction (QF-PCR) and followed by chromosomal microarray analysis (CMA). Those with normal CMA were informed of the option of trio ES. Results: QF-PCR detected chromosomal abnormality in 4 cases (4/110, 3.6%), including 1 of XXY, 1 of XYY and 2 of triploidy. The remaining 106 cases were tested by CMA, with pathogenic copy number variations (CNVs) detected in 5 cases (5/106, 4.7%), and uniparental disomy (UPD) in 2 cases (2/106, 1.9%). As an option for cases with a normal CMA, ES was accepted by 12 non-isolated cases, and pathogenic or likely pathogenic variants were detected in 5, involving the following genes: PBX1, FREM2, PKHD1 and BBS2, with a 41.7% (5/12) diagnostic rate. Conclusion: We provided further evidence of using advanced genetic approaches for oligohydramnios pregnancy. Non-isolated oligohydramnios increases the risk of having monogenetic conditions.

The investigation was motivated by the widespread use of ultra-high-strength steels in cable-stayed bridges and armor steel plates. These structures are exposed to elevated risks from extreme loads, including vehicle impacts and blast loadings. The study aimed to investigate the mechanical properties of 1770 steel for applications in extreme conditions. The strain rates and temperatures ranged from 0.00095 s−1 to 1303 s−1 and 20 °C–900 °C, respectively. Tensile tests were conducted at various strain rates using a Split Hopkinson Tension Bar for dynamic testing and a universal testing machine for quasi-static testing at room temperature (20 °C). Quasi-static tension at elevated temperatures was carried out using an electromechanical testing machine coupled with a heating device. A uniform temperature distribution inside the specimens was ensured by a 30-min holding time. The results of the tensile test indicate that the 1770 steel displays notable thermal softening effects and strain rate hardening that differ from mild steel. The standard Johnson-Cook (J-C) model was found to be inadequate in accurately predicting the strain rate effects of this specimen. To address this issue, the strain rate parameter C in the standard model was adjusted to create the modified J-C model, which demonstrated good agreement with the experimental results. To further demonstrate the modified model and the identified parameters, drop hammer impact tests and corresponding numerical simulations were conducted. The impact test and numerical simulation results showed good agreement in terms of deformation and contact force. The mechanical properties and the constitutive models can serve as a design reference for the ultra-high-strength 1770 steel in extreme envirnments, as well as a theoretical basis for fitting material models of similar ultra-high-strength steels.