Objective To observe in vitro the effect of mechanical stress at different intensities on the pro-liferation, apoptosis and extracellular matrix of degenerative human nucleus pulposus cells. Methods The cells were isolated and cultured in vitro, and divided into a control group, a low-intensity group, a medium-intensity group and a high-intensity group. The low-, medium- and high-intensity groups were stretched mechanically by 1000 μ, 2000μor 4000μrespectively for 6 hours using a four-point bending system, while the control group was not stressed. Flow cytometry was used to explore any changes in the cell cycle and the proliferation index ( PI) . The expression of proliferating cell nuclear antigen ( PCNA) , B-cell lymphoma-2 ( BCL-2)/Bax, collagen II and aggrecan were meas-ured using real-time quantitative polymerase chain reactions. Results The mechanical stretching significantly influ-enced proliferation, apoptosis and the extracellular matrices compared with the control group. The PI and PCNA ex-pression increased at first and then decreased gradually with the exercise intensity. Compared with the control group, the mRNA expression level of Bcl-2/Bax increased significantly to 1.53 times that of the control group after 1000 μstretching, but to only 0.71 times that of the control group at 2000μand 0.43 times at 4000μ. The gene expression of collagen II increased significantly by 1. 1 times and that of aggrecan by 1. 3 times after 1000 μ stress stimulation compared with the control group ( P≤0.05) . However, the expression of collagen II and aggrecan was inhibited sig-nificantly at 2000 and 4000 μ , with the lowest levels at 4000 μ (P≤0.05). Conclusion Stretching at different intensities has different effects on the proliferation, apoptosis and extracellular matrix of human pulposus cells with degenerate nuclei.

Background: Previous studies have shown that body composition is associated with chronic kidney disease (CKD), and perimenopause is associated with increased fat mass and decreased lean body mass. Muscle wasting is common among patients with CKD. Sarcopenic obesity (SO) refers to excess adiposity with decreased muscle mass. However, little is known about the relationship between SO and renal function decline. Here, we identified the relationship between SO and decreased estimated glomerular filtration rate (eGFR) in postmenopausal women. Methods: We conducted a cross-sectional study based on the data from the Korea National Health and Nutrition Examination Survey (2008–2011). We analyzed 4,560 postmenopausal women who underwent dual energy X-ray absorptiometry. Sarcopenia was defined based on weight-adjusted appendicular skeletal muscle mass. Obesity was defined based on body mass index. The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Subjects were classified into four groups: normal, obese, sarcopenic, and sarcopenic obese. Logistic regression analysis was performed to examine the association between SO and decreased eGFR. The results were adjusted for variable confounders. Results: In the unadjusted model, the odds ratio (OR) of decreased eGFR for SO was 1.67 (95% confidence interval [CI], 1.23–2.26). The obese and sarcopenic groups had ORs of 0.67 (95% CI, 0.44–1.03) and 0.70 (95% CI, 0.44–1.10), respectively. After controlling for confounding variables, there was also a significant association between SO and decreased eGFR (adjusted OR, 1.48; 95% Cl, 1.05–2.07). Conclusion SO was independently associated with decreased eGFR in postmenopausal Korean women.

Objective Developing a new type of full-face respiratory protective mask for nuclear facility sites to enhance the sound transmission function and improve the facial adaptability. Methods Combined with feedback from on-site practical needs, this study utilized finite element simulation and ergonomic design methods to investigate the voice transmission units of full-face masks and the facial features of workers at key nuclear facilities. Based on the research results, a new full-face respiratory protection mask structure was designed. Results The optimized structure of passive thin film voice transmission unit significantly enhanced voice transmission efficiency, reducing average voice transmission loss by approximately 70% compared to the control group using thin plate units of equivalent thickness. The existing facial feature test panels insufficiently cover and unevenly classify the facial features of workers at key nuclear facilities. In this study, a specialized test panel based on measurement data achieved a total coverage of 98.5% with high distribution uniformity within each class, providing effective guidance for redesigning full-face mask structural parameters. In comparison to foreign products currently utilized in nuclear facilities, the newly designed full-face mask structure exhibited excellent tightness and structural safety and reliability, and can be cleaned, decontaminated, and reused. Conclusion The results of this study provide significant guidance for improving and optimizing full-face respiratory protection mask used at nuclear facilities, as well as promoting domestic production of high-quality full-face respiratory protection masks.