Background The job content of aircraft maintenance workers is complex, with high intensity and high requirements, and they are prone to work-related musculoskeletal disorders (WMSDs), but related research is relatively rare. Objective To investigate the positive rate of WMSDs among aircraft maintenance workers, evaluate ergonomic load, and analyze the risk factors of WMSDs. Methods We used a self-compiled questionnaire for WMSDs and the Quick Exposure Checklist (QEC) to investigate the basic situation, positive rate of WMSDs, and the ergonomic load of 2271 male maintenance workers in 6 departments of an aircraft maintenance company, including airline maintenance, overall overhaul, accessory/landing gear overhaul, engine overhaul, product customization, and power assist. We used a logistic regression model to analyze the risk factors of WMSDs in the neck, shoulder, hand/wrist, and lower back. Results The positive rate of WMSDs in the past 12 months was 70.4% (1598/2271) and the positive rate of WMSDs in different body parts ranged from 6.6% to 49.5%, with the top three parts of lower back, neck, and knee, respectively. There were statistically significant differences in the positive rate among different departments (P<0.05). The average QEC scores for neck, hand/wrist, and back (static) were moderate, while those for shoulder and back (dynamic) were high, and the body part specific positive rate of WMSDs increased with the increase of ergonomic load level. Working years (5-<10 years, ≥20 years), working with back flexed or twisted or side bent (moderately, excessively), high maximum force level exerted by one hand, and feeling difficult (sometimes, often) and stressful (moderately, very) while working were associated with higher risks of lower back pain (OR=1.486, 1.505; 2.151, 3.769; 1.637; 2.110, 2.407; 1.637, 1.794; P<0.05). Working years (15-<20 years, ≥20 years), working with head/neck bent or twisted (occasionally, continuously), feeling difficult (sometimes) and stressful (very) while working were associated with higher risks of neck pain (OR=1.731, 1.586; 3.732, 8.341; 1.633; 1.696; P<0.05). Working years (15-<20 years, ≥20 years), working with hands in a high position (at shoulder or above), very frequent shoulder/arm movements, feeling difficult (sometimes, often) and stressful (moderately, very) while working were associated with higher risks of shoulder pain (OR=1.587, 1.709; 1.299; 1.521; 1.643, 2.239; 1.659, 1.977; P<0.05). Working with wrist at deviated or bent angle, high repetition of similar movements, feeling difficult (sometimes, often) and stressful (moderately, very) while working were associated with higher risks of hand/wrist pain (OR=1.692; 1.670; 1.827, 2.884; 2.190, 2.625; P <0.05) . Physical exercise after work (≥3 times·week⁻¹) was associated with a lower risk of neck pain (OR=0.582, P<0.05). Shift workers were at a lower risk of shoulder pain and hand/wrist pain (OR=0.737 and 0.554, P<0.05). Conclusion The high positive rate of WMSDs symptoms among aircraft maintenance workers is related to individual, occupational ergonomic, and psychological factors, and active prevention and intervention should be taken.

Background/Aims: Dexamethasone (DEX) is a widely used exogenous therapeutic glucocorticoid in clinical settings. Its long-term use leads to many side effects. However, its effect on metabolic disorders in individuals on a high-fat diet (HFD) remains poorly understood. Methods: In this study, HFD-fed mice were intraperitoneally injected with DEX 2.5 mg/kg/day for 30 days. Lipid metabolism, adipocyte proliferation, and inflammation were assayed using typical approaches. Results: DEX increased the epididymal fat index and epididymal adipocyte size in HFD-fed mice. The number of epididymal adipocytes with diameters > 70 μm accounted for 0.5% of the cells in the control group, 30% of the cells in the DEX group, 19% of the cells in the HFD group, and 38% of all the cells in the D+H group. Adipocyte proliferation in the D+H group was inhibited by DEX treatment. Adipocyte enlargement in the D+H group was associated with increased the lipid accumulation but not the adipocyte proliferation. In contrast, the liver triglyceride and total cholesterol levels and their metabolism were downregulated by the same treatment, indicating the therapeutic potential of DEX for nonalcoholic fatty liver disease. Conclusions DEX synergizes with HFD to promote lipid deposition in adipose tissues. A high risk of obesity development in patients receiving HFD and DEX treatment is suggested.

Background/Aims: Dexamethasone (DEX) is a widely used exogenous therapeutic glucocorticoid in clinical settings. Its long-term use leads to many side effects. However, its effect on metabolic disorders in individuals on a high-fat diet (HFD) remains poorly understood. Methods: In this study, HFD-fed mice were intraperitoneally injected with DEX 2.5 mg/kg/day for 30 days. Lipid metabolism, adipocyte proliferation, and inflammation were assayed using typical approaches. Results: DEX increased the epididymal fat index and epididymal adipocyte size in HFD-fed mice. The number of epididymal adipocytes with diameters > 70 μm accounted for 0.5% of the cells in the control group, 30% of the cells in the DEX group, 19% of the cells in the HFD group, and 38% of all the cells in the D+H group. Adipocyte proliferation in the D+H group was inhibited by DEX treatment. Adipocyte enlargement in the D+H group was associated with increased the lipid accumulation but not the adipocyte proliferation. In contrast, the liver triglyceride and total cholesterol levels and their metabolism were downregulated by the same treatment, indicating the therapeutic potential of DEX for nonalcoholic fatty liver disease. Conclusions DEX synergizes with HFD to promote lipid deposition in adipose tissues. A high risk of obesity development in patients receiving HFD and DEX treatment is suggested.

Background/Aims: Dexamethasone (DEX) is a widely used exogenous therapeutic glucocorticoid in clinical settings. Its long-term use leads to many side effects. However, its effect on metabolic disorders in individuals on a high-fat diet (HFD) remains poorly understood. Methods: In this study, HFD-fed mice were intraperitoneally injected with DEX 2.5 mg/kg/day for 30 days. Lipid metabolism, adipocyte proliferation, and inflammation were assayed using typical approaches. Results: DEX increased the epididymal fat index and epididymal adipocyte size in HFD-fed mice. The number of epididymal adipocytes with diameters > 70 μm accounted for 0.5% of the cells in the control group, 30% of the cells in the DEX group, 19% of the cells in the HFD group, and 38% of all the cells in the D+H group. Adipocyte proliferation in the D+H group was inhibited by DEX treatment. Adipocyte enlargement in the D+H group was associated with increased the lipid accumulation but not the adipocyte proliferation. In contrast, the liver triglyceride and total cholesterol levels and their metabolism were downregulated by the same treatment, indicating the therapeutic potential of DEX for nonalcoholic fatty liver disease. Conclusions DEX synergizes with HFD to promote lipid deposition in adipose tissues. A high risk of obesity development in patients receiving HFD and DEX treatment is suggested.

OBJECTIVE To investigate the effects and potential mechanism of persimmon leaf （PL） extract against ferroptosis induced by H2O2 in IEC-6 cells. METHODS Using IEC-6 cells as object， the effects of ferroptosis inhibitor ferrostatin-1 on IEC-6 cell viability induced by H2O2 were investigated； IEC-6 cells were divided into control group， H2O2 group， H2O2+PL 25 μg/mL group and H2O2+PL 50 μg/mL group. The levels of oxidant stress indexes [content of malondialdehyde （MDA）， activity of superoxide dismutase （SOD）， and levels of reactive oxygen species （ROS）]， mitochondrial membrane potential （MMP） as well as mRNA and protein expressions of nuclear factor-erythroid-2 related factor 2 （Nrf2）， heme oxygenase-1 （HO-1）， NADPH/quinone oxidoreductase-1 （NQO-1）， cystine/glutamate anti-porter （xCT）， glutathione peroxidase 4 （GPX4） and ferritin heavy chain （FTH） were detected. RESULTS Ferroptosis inhibitor ferrostatin-1 could significantly increase the survival rate of H2O2-induced cells （P＜ 0.01）. Compared with the control group， MDA content， ROS level， mRNA expressions of Nrf2 and NQO-1 as well as protein expressions of Nrf2 and HO-1 were increased or up-regulated significantly， while SOD activity， MMP， mRNA expressions of xCT， GPX4 and FTH as well as protein expressions of GPX4 and FTH were decreased or down-regulated significantly （P＜0.01 or P＜0.05）. Compared with the H2O2 group， oxidative stress Δ indexes of H2O2+PL 25， 50 μg/mL groups were reversed to different extents， MMP level was increased significantly， as well as mRNA and protein expressions of Nrf2， HO-1， NQO-1，xCT， GPX4 and FTH were up-regulated to different extents；there were statistical significances in some indexes between groups （P＜0.01 or P＜0.05）. CONCLUSIONS PL extract can alleviate mitochondrial membrane damage and abnormal accumulation of ROS caused by H2O2， which may be related to the inhibition of ferroptosis by activating the Nrf2/HO-1 signaling pathway.

Background/Aims: Dexamethasone (DEX) is a widely used exogenous therapeutic glucocorticoid in clinical settings. Its long-term use leads to many side effects. However, its effect on metabolic disorders in individuals on a high-fat diet (HFD) remains poorly understood. Methods: In this study, HFD-fed mice were intraperitoneally injected with DEX 2.5 mg/kg/day for 30 days. Lipid metabolism, adipocyte proliferation, and inflammation were assayed using typical approaches. Results: DEX increased the epididymal fat index and epididymal adipocyte size in HFD-fed mice. The number of epididymal adipocytes with diameters > 70 μm accounted for 0.5% of the cells in the control group, 30% of the cells in the DEX group, 19% of the cells in the HFD group, and 38% of all the cells in the D+H group. Adipocyte proliferation in the D+H group was inhibited by DEX treatment. Adipocyte enlargement in the D+H group was associated with increased the lipid accumulation but not the adipocyte proliferation. In contrast, the liver triglyceride and total cholesterol levels and their metabolism were downregulated by the same treatment, indicating the therapeutic potential of DEX for nonalcoholic fatty liver disease. Conclusions DEX synergizes with HFD to promote lipid deposition in adipose tissues. A high risk of obesity development in patients receiving HFD and DEX treatment is suggested.

Background/Aims: Dexamethasone (DEX) is a widely used exogenous therapeutic glucocorticoid in clinical settings. Its long-term use leads to many side effects. However, its effect on metabolic disorders in individuals on a high-fat diet (HFD) remains poorly understood. Methods: In this study, HFD-fed mice were intraperitoneally injected with DEX 2.5 mg/kg/day for 30 days. Lipid metabolism, adipocyte proliferation, and inflammation were assayed using typical approaches. Results: DEX increased the epididymal fat index and epididymal adipocyte size in HFD-fed mice. The number of epididymal adipocytes with diameters > 70 μm accounted for 0.5% of the cells in the control group, 30% of the cells in the DEX group, 19% of the cells in the HFD group, and 38% of all the cells in the D+H group. Adipocyte proliferation in the D+H group was inhibited by DEX treatment. Adipocyte enlargement in the D+H group was associated with increased the lipid accumulation but not the adipocyte proliferation. In contrast, the liver triglyceride and total cholesterol levels and their metabolism were downregulated by the same treatment, indicating the therapeutic potential of DEX for nonalcoholic fatty liver disease. Conclusions DEX synergizes with HFD to promote lipid deposition in adipose tissues. A high risk of obesity development in patients receiving HFD and DEX treatment is suggested.

In the context of the emphasis on the claims of multiple subjects in fourth-generation educational evaluation, the subjective experience of students has gradually become one of the key contents of educational evaluation. However, there is still a vague understanding of the conceptual source, specific definition, and measurement indicators of the student experience theory, and a more systematic theoretical system has not yet been formed. With the UE user experience thinking in the business field as the core meta-theory, this article integrates value-added evaluation and the idea of three-source flow, elaborates on the core concept connotation of compound student experience teaching evaluation, and builds a five-dimensional evaluation model for student experience with "aesthetic experience, interactive experience, emotional experience, behavioral experience, and discursive experience" as the first-level indicators based on literature research, expert interviews, and multi-round group discussions. It is hoped that student evaluation will force teachers to improve the contents and form of teaching and help to achieve breakthrough reform of the teaching system as a whole.

Objective:To optimize the dispensing method of national drug standard substances and develop a novel adjustable quantitative dispensing device for improving dispensing efficiency and production quality.Methods:Stain-less steel was used to fabricate an adjustable volume tank and a matching scraper for dispensing powder samples of fixed volume.Results:31 types of uniform powder samples,including chemicals and pharmaceutical excipients,were dispensed using the dispensing device.It showed a small test fluctuation range,high accuracy,and consistent effectiveness among different samples.The dispensing efficiency was improved by 147％compared to the conventional method of single-weight dispensing using a balance.Conclusion:The device can significantly reduce dispensing time,increase production efficiency,and meet the dispensing specifications for drug standard substances,which brings remarkable convenience and value to the production and preparation of drug standard substances.

In order to meet the needs of the comprehensive development of life sciences and medicine,and fulfill the coher-ence and intersectionality of undergraduate experimental courses,it is necessary to break the teaching contents of conventional single experiment courses,and carry out the teaching reform of tumor comprehensive experimental course.Molecular biology and immuno-logy are two basic subjects which are closely related to the scientific research of life science,basic medicine and clinical medicine.Meantime,they are important sources for students to acquire skill training and scientific thinking as well.In this study,we try to inte-grate the experimental courses about the analysis and intervention of tumor-related genes based on the molecular biology and immunology technologies,facilitating to establish a new tumor comprehensive experimental course system.The course focuses on the development of students'logical thinking,and simulates the scientific research process through database screening,experimental operation,experi-mental report and paper writing,so as to significantly improve undergraduates'interest in scientific research and their ability to com-bine theory with practice,and cultivate students'rigorous scientific and innovative thinking ability as well as their ability to compre-hensively analyze and solve problems.It lays a solid foundation for future postgraduate related scientific research.At the same time,it is helpful to train teachers with multi-disciplinary knowledge reserves,and promote the coordinated development of scientific research through teaching.