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To improve the energy dissipation capacity of rubber isolation bearings, it is important to find a new rubber material with good applicability and high damping properties. Two types of blends were prepared using nitrile rubber (NBR), brominated butyl rubber (BIIR) and ethylene-vinyl acetate copolymer (EVA): NBR/BIIR and NBR/BIIR/EVA. The vulcanization, mechanical and damping properties of the blends were analyzed. The results show that both blends exhibit excellent vulcanization plateaus and mechanical properties. For NBR/BIIR, as the BIIR content increases, the complementary effects of NBR and BIIR afforded by blending are enhanced. Two damping peaks appeared in the tanδ-T curve and shifted toward lower and higher temperatures, respectively, which clearly widened the effective damping temperature range. However, the damping value in the valley of the tanδ-T curve was as low as 0.39. For NBR/BIIR/EVA, the addition of EVA greatly increased damping in the valley of the tanδ-T curve to approximately 0.54. EVA was observed to be the optimal polymer for improving the compatibility of the NBR/BIIR blend. Moreover, hot air thermal aging tests showed that both blends demonstrated good stability.

Background In the context of scaling up free antiretroviral therapy (ART), healthcare equality is essential for people living with HIV. We aimed to assess socioeconomic-related inequalities in uptake of continuous care for people living with HIV receiving ART, including retention in care in the last six months, routine toxicity monitoring, adequate immunological and virological monitoring, and uptake of mental health assessment in the last 12 months. We also determined the contributions of socioeconomic factors to the degree of inequalities. Methods A hospital-based cross-sectional survey was conducted among consecutive clients visiting an HIV treatment center in Kunming, China in 2019. Participants were 702 people living with HIV aged ≥18 years (median age: 41.0 years, 69.4% male) who had been on ART for 1–5 years. Socioeconomic-related inequality and its contributing factors were assessed by a normalized concentration index (CIn) with a decomposition approach. Results The uptake of mental health assessment was low (15%) but significantly higher among the rich (CIn 0.1337, 95% CI: 0.0140, 0.2534). Retention in care, toxicity, and immunological monitoring were over 80% but non-significant in favor of the rich (CIn: 0.0117, 0.0315, 0.0736, respectively). The uptake of adequate virological monitoring was 15% and higher among the poor (CIn = -0.0308). Socioeconomic status positively contributed to inequalities of all care indicators, with the highest contribution for mental health assessment (124.9%) and lowest for virological monitoring (2.7%). Conclusions These findings suggest virological monitoring and mental health assessment be given more attention in long-term HIV care. Policies allocating need-oriented resources geared toward improving equality of continuous care should be developed.

To evaluate the predictive effect of T-lymphoid subsets on the conversion of common covid-19 to severe. The laboratory data were collected retrospectively from common covid-19 patients in the First People's Hospital of Zaoyang, Hubei Province, China and the Third People's Hospital of Kunming, Yunnan Province, China, between January 20, 2020 and March 15, 2020 and divided into training set and validation set. Univariate and multivariate logistic regression was performed to investigate the risk factors for the conversion of common covid-19 to severe in the training set, the prediction model was established and verified externally in the validation set. 60 (14.71%) of 408 patients with common covid-19 became severe in 6–10 days after diagnosis. Univariate and multiple logistic regression analysis revealed that lactate (P = 0.042, OR = 1097.983, 95% CI 1.303, 924,798.262) and CD8+ T cells (P = 0.010, OR = 0.903, 95% CI 0.835, 0.975) were independent risk factors for general type patients to turn to severe type. The area under ROC curve of lactate and CD8+ T cells was 0.754 (0.581, 0.928) and 0.842 (0.713, 0.970), respectively. The actual observation value was highly consistent with the prediction model value in curve fitting. The established prediction model was verified in 78 COVID-19 patients in the verification set, the area under the ROC curve was 0.906 (0.861, 0.981), and the calibration curve was consistent. CD8+ T cells, as an independent risk factor, could predict the transition from common covid-19 to severe.

IntroductionVarious drugs are first line anti-TB drugs for more than thirty years. Since ferulic acid have shown promising inhibition growth of M. tuberculosis and M. smegmatis cell.ObjectiveIn this study, we have explored the inhibitory effect of ferulic acid against Mycobacterium tuberculosis topoisomerase I. We further investigated the mechanism of ferulic acid by various experiments.MethodsDNA relaxation assays was done for supercoiled pUC18 DNA, oligonucleotide cleavage assay was performed for 5ʹ-end-labeled 32-mer harboring the STS (Strong Topoisomerase Site) annealed to a complimentary sequence. Growth inhibition (MIC) values were calculated by performing resazurin reduction microplate assay (REMA).ResultsIn this study, we describe the growth inhibition of M. tuberculosis and M. smegmatis through Mycobacterium tuberculosis topoisomerase I (MttopoI) by ferulic acid. We have further investigated the mechanism of ferulic acid by analysing the two step of topoisomerase 1 (topoI) reaction cycle. Ferulic acid was able to stimulate cleavage which further leads to cleavage-relegation equilibrium. Moreover, it was shown that ferulic acid inhibited topoI overexpressing cells at low minimum inhibitory concentration (MIC). Ferulic acid affects the activity of DNA relexation in the mutations in DxDxE motif of metal binding mutants which contributes to the reaction of enzyme with the drug.ConclusionIn conclusion, our results indicate that ferulic acid leads to combat microbial infection and act as toxins to MstopoI and MttopoI. Moreover, targeting metal coordination to topoisomerases might be a general strategy to develop new lead molecules.