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Objectives The study aims to identify the outcome and the related factors of unvaccinated patients with end-stage kidney disease during the Omicron pandemic.Design A multicentre retrospective study of patients with end-stage kidney disease undergone maintenance haemodialysis (HD) in China.Setting 6 HD centres in China.Participants A total of 654 HD patients who tested positive for SARS-CoV-2 were ultimately included in the study.Outcome measures The primary outcomes of interest were adverse outcomes, including hospitalisation due to COVID-19 and all-cause mortality.Results The average age of the patients was 57 years, with 33.6% of them being over 65 years. Among the patients, 57.5% were male. During the follow-up period, 158 patients (24.2%) experienced adverse outcomes, and 93 patients (14.2%) died. The majority of patients (88/158) developed adverse outcomes within 30 days, and most deaths (77/93) occurred within 1 month. An advanced multivariable Cox regression analysis identified that adverse outcomes were associated with various factors while all-cause mortality was related to advanced age, male gender, high levels of C reactive protein (CRP) and low levels of prealbumin. The Kaplan-Meier curves demonstrated significantly higher all-cause mortality rates in the older, male, high CRP and low prealbumin subgroups.Conclusions Among unvaccinated HD patients with confirmed Omicron infections, various factors were found to be linked to adverse outcomes. Notably, age, sex, CRP and prealbumin had a substantial impact on the risk of all-cause mortality.

Because of the prevalent time-delay characteristics in real-world phenomena, this paper investigates the existence of mild solutions for diffusion equations with time delays and the Hilfer fractional derivative. This derivative extends the traditional Caputo and Riemann–Liouville fractional derivatives, offering broader practical applications. Initially, we constructed Banach spaces required to handle the time-delay terms. To address the challenge of the unbounded nature of the solution operator at the initial moment, we developed an equivalent continuous operator. Subsequently, within the contexts of both compact and non-compact analytic semigroups, we explored the existence and uniqueness of mild solutions, considering various growth conditions of nonlinear terms. Finally, we presented an example to illustrate our main conclusions.

We primarily investigate the existence of solutions for fractional neutral integro-differential equations with nonlocal initial conditions, which are crucial for understanding natural phenomena. Taking into account factors such as neutral type, fractional-order integrals, and fractional-order derivatives, we employ probability density functions, Laplace transforms, and resolvent operators to formulate a well-defined concept of a mild solution for the specified equation. Following this, by using fixed-point theorems, we establish the existence of mild solutions under more relaxed conditions.

AbstractPurpose Little is known about the effect of visit-to-visit ultrafiltration volume (UV) variability on the outcome. In this study, we investigated the association between visit-to-visit UV variability and all-cause mortality in patients receiving hemodialysis (HD).Methods We consecutively enrolled patients who received maintenance HD in our center from March 2015 to March 2021. UV variability was defined using standard deviation (UVSD) and coefficient of variation (UVCV) (standard deviation divided by the mean). The relationship between UV variability and all-cause mortality was assessed using univariate and multivariate Cox proportional hazard regression models. Receiver operating characteristic curves were used to evaluate the predictive abilities of UVSD and UVCV for short-term and long-term survival rates.Results A total of 283 HD patients were included. The mean age was 57.54 years, and 53% were males. Follow-up was done for a median of 3.38 years (IQR 1.83–4.78). During the follow-up period, 73 patients died. Cox proportional hazards models indicated that UVSD and UVCV (higher versus lower) were positively associated with all-cause mortality (p=.003 and p

The impact of vaccination on the outcomes of dialysis patients with Omicron infections in China remains unknown. This study aimed to examine the relationship between vaccination and hospitalization as well as all-cause mortality. We included patients who had undergone maintenance hemodialysis (HD) for at least three months at our center. The follow-up period spanned from December 2022 to February 2023. We assessed the connections between vaccination and hospitalization as well as all-cause mortality using univariable and multivariable logistic regression models. Receiver operating characteristic (ROC) curves were used to assess the diagnostic accuracy for hospitalization and all-cause mortality. Ultimately, a total of 427 HD patients with confirmed SARS-CoV-2 infections were included. The patients had a mean age of 54 years, and 59.4% of them were male. Prior to the investigation, 108 patients had received vaccinations, with 81 of them having completed or received booster vaccinations. Throughout the follow-up period, 81 patients were admitted to the hospital, and 39 patients died. Multivariable logistic regression revealed that vaccination significantly decreased all-cause mortality (OR 0.25, 95% CI 0.07–1.94, P = .04). Moreover, completed or booster vaccinations were effective in reducing the hospitalization rate (OR 0.41, 95%CI 0.17–0.99, P = .047). It is noteworthy that both unvaccinated and vaccinated individuals experienced mild symptoms, and the hospitalization rates were relatively low in both groups. Despite the reduced pathogenicity of Omicron compared to previous strains in dialysis patients, both vaccinated and unvaccinated, vaccination still provides benefits for improving the prognosis.

This study used finite element analysis (FEA) to model the effects of adhesive Z-connections on the thickness swelling of laminated wood composites exposed to water. We hypothesized that the area density, diameter, and spatial distribution of adhesive Z-connections will influence the ability of Z-connections to restrain thickness swelling of the composites. We tested this hypothesis by modelling a wood composite in ANSYS FEA software v. 17.0 to explore the effect of moisture on the thickness swelling of the wood composite. The results were compared with those obtained experimentally. We then examined the effect of the area density, size (diam.), and spatial distribution of the adhesive Z-connections on the thickness swelling of wood composites. Our results showed a positive correlation between the number of adhesive Z-connections in the composites and restriction of thickness swelling following 72 h of simulated moisture diffusion. Similarly, increasing the size of adhesive Z-connections also restricted thickness swelling. In contrast, different spatial distributions of Z-connections had little effect on restraining thickness swelling. Our modelling approach opens up opportunities for more complex designs of adhesive Z-connections, and also to examine the effect of wood properties, such as permeability, density, and hygroscopic swelling ratios on the thickness swelling of laminated wood composites.

The utilization of recycled coarse aggregate (RCA) from construction and demolition waste (CDW) is a sustainable solution to protect the fragile natural environment and save the diminishing natural resources. The current study was aimed at exploring the impact resistance and mechanical properties of recycled aggregate concrete (RAC) affected by hooked-end steel fiber (HF) and crimped steel fiber (CF). Fifteen concrete mixtures considering different RCA substitution ratio, steel fiber dosage, and steel fiber shapes were designed. Meanwhile, a statistical analysis method-based Weibull distribution was introduced to evaluate the variations of impact test results, presented using a reliability function. Lastly, the microstructural morphologies of interfacial transition zones at the cement paste/aggregate and cement paste/fiber interfaces were observed using a scanning electron microscope (SEM). The experimental results showed that the impact resistance and mechanical properties mildly decreased with the increase in substitution ratio of RCA, whereas they conclusively increased with the increase in steel fiber content. Steel fiber recycled aggregate concrete (SFRAC) with 1.5% steel fiber content had the best impact resistance, and its initial cracking times and final failure times were 3.25–4.75 and 8.78–29.08 times those of plain RAC, respectively. HF has better impact resistance than CF. The SEM observations of microstructures indicated that the hardened cement paste of natural aggregate concrete (NAC) was more compact than that of RAC. Steel fiber had a better connection with the cement paste interface than that of aggregate and cement paste owing to better thermal conductivity. This research could be a guide for SFRAC as a structural material in practical engineering, steering the construction industry toward the circular economy.

In this paper we test the hypothesis that adhesive through-reinforcement in combination with glass-fibre reinforcement of adhesive bond lines will significantly improve the fracture toughness of a laminated birch wood composite. We test this hypothesis using a model composite consisting of perforated veneer that allowed a polyurethane adhesive to penetrate and reinforce veneers within the composite. Model composite specimens were tested for mode I fracture properties, and scanning electron microscopy was used to examine the microstructure of fracture surfaces. Our results clearly show that through-reinforcement, and also reinforcing adhesive bond lines with glass-fibre, significantly improved fracture toughness of the birch wood composite. Our results also indicate that improvements in fracture toughness depended on the level of reinforcement. Improvements in fracture toughness were related to the ability of the reinforcement to arrest crack development during fracture testing and the fibre bridging effect of glass-fibre in adhesive bond lines. We conclude that through-reinforcement is an effective way of improving the fracture toughness of laminated wood composites, but further research is needed to develop practical ways of creating such reinforcement in composites that more closely resemble commercial products.