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The relationship between depression and obesity has been confirmed by multiple studies. Compared to conventional measurement indicators such as body mass index or waist circumference, the body roundness index (BRI) demonstrates higher accuracy in assessing body fat content, especially visceral adiposity. Nevertheless, despite the advantages of BRI in measuring fat, the specific link between BRI and depression remains unclear. This study aims to clarify the potential correlation using data from the China Health and Retirement Longitudinal Study (CHARLS). This study used CHARLS data from 2015 and 2020. We screened and included 7,258 middle-aged and older adults without depressive symptoms at baseline. We explored the connection between BRI and depression risk through logistic regression analyses, restricted cubic spline analyses, subgroup analyses, and interaction tests. After adjusting for covariates, a positive correlation was observed between BRI and depression risk. Specifically, a one-unit increase in BRI led to a 14% increase in depression risk (OR =  1.14, 95% CI: 1.09-1.20, P <  0.001). BRI is linked to a higher risk of depression in middle-aged and older adults in China and can be used as a simple indicator to predict depression.

The study of the adsorption characteristics of coal is of great significance to gas prevention and CO 2 geological storage. To explore the adsorption mechanism of coal, this study focuses on columnar anthracite. Adsorption tests on coal rock under a range of physical field conditions were conducted using the volumetric method. The adsorption characteristics of anthracite for CO 2 , CH 4 , and N 2 gases under different conditions were investigated using Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) methods. The results showed that the adsorption capacities of anthracite for these three gases are in the order of CO 2 > CH 4 > N 2 , and that the adsorption capacity increases with increasing gas injection pressure. The CO 2 /CH 4 /N 2 gas molecule adsorption capacity of the anthracite macromolecular structure model decreases with increasing temperature. The increase in temperature has the greatest influence on the CO 2 absorption capacity, followed by the CH 4 and N 2 adsorption capacities. The research offers a theoretical basis for the control of coal mine gas and the geological storage of CO 2 .

The regularized ψ-Hilfer derivative within the sense of Caputo is an improved version of the ψ-Hilfer fractional derivative, primarily because it addresses the issue where the initial conditions of problems involving the ψ-Hilfer fractional derivative lack clear physical significance unless p=1. This article’s main contribution is the use of the ψ-Laplace transform, which is the first to provide an explicit expression for mild solutions to the fractional diffusion equations with the regularized ψ-Hilfer derivative. Additionally, we investigate the existence and attractivity of mild solutions for fractional diffusion equations involving the regularized ψ-Hilfer fractional derivatives. Finally, we provide two examples to illustrate our main results.

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.

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). 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. 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<.001, respectively), while in multivariable-adjusted models, only higher UVCV remained significantly associated with all-cause mortality in patients receiving HD (HR 2.55 (95% CI 1.397-4.654), p=.002). Moreover, subgroup analyses showed that the predictive performance of UVCV was more accurate among older patients, males and patients with comorbidities. Visit-to-visit UV variability, especially UVCV, is a helpful indicator for predicting all-cause mortality in patients receiving HD, especially for older patients, males and those with comorbidities.

To investigate the relationship between load, damage, and fatigue life of complex engineering components under stress, this paper modifies the existing continuous nonlinear damage model based on the distortion energy density theory to reflect the usage and stress characteristics of Q345 steel components in bridges. A nonlinear damage model that accounts for actual complex stress conditions is proposed, and the model parameters are calculated using twist–bending fatigue test data. The cumulative damage predicted by the modified model under varying fatigue stress levels is analyzed as a function of the number of fatigue cycles. Furthermore, the modified model is microscopically validated through scanning electron microscopy (SEM) observation and analysis of twist–bending fatigue unloading specimens. Finally, according to the engineering application of the modified model in the complex load environments of steel bridges, a comparative analysis is conducted between the general nonlinear damage model, the modified nonlinear damage model, and the actual damage observed in bridge components. The actual component damage, calculated based on the component’s natural frequency, closely matches the damage predicted by the nonlinear damage correction model using bridge monitoring data. In contrast, a significant discrepancy exists between the damage values predicted by the nonlinear damage correction model and those from the general nonlinear damage model. The observed discrepancy confirms the improvement effect and engineering significance of the modified nonlinear damage theory. Furthermore, the study reveals that under the same equivalent stress amplitude, reliability decreases nonlinearly as the expected service life increases. Conversely, for a fixed expected service life, reliability declines more rapidly with higher equivalent stress amplitudes.

This article aims to explore the existence and stability of solutions to differential equations involving a ψ-Hilfer fractional derivative in the Caputo sense, which, compared to classical ψ-Hilfer fractional derivatives (in the Riemann–Liouville sense), provide a clear physical interpretation when dealing with initial conditions. We discovered that the ψ-Hilfer fractional derivative in the Caputo sense can be represented as the inverse operation of the ψ-Riemann–Liouville fractional integral, and used this property to prove the existence of solutions for linear differential equations with a ψ-Hilfer fractional derivative in the Caputo sense. Additionally, we applied Mönch’s fixed-point theorem and knowledge of non-compactness measures to demonstrate the existence of solutions for nonlinear differential equations with a ψ-Hilfer fractional derivative in the Caputo sense, and further discussed the Ulam–Hyers–Rassias stability and semi-Ulam–Hyers–Rassias stability of these solutions. Finally, we illustrated our results through case studies.

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.

Hemodialysis patients frequently experience chronic inflammation and malnutrition, while C-reactive protein to prealbumin ratio (CP ratio) is a comprehensive assessment approach of inflammatory and nutritional status. Howerer, there is limited research on the prognostic value of the CP ratio specifically in hemodialysis patients infected with the Omicron variant. Data from 847 hemodialysis patients, diagnosed with Omicron across 6 hemodialysis centers between December 2022 and February 2023, were analyzed. Hazard ratios were estimated using univariate and multivariable Cox regression, and receiver operating characteristic curves were used to evaluate the predictive abilities. Survival rate differences between higher and lower CP ratio groups were analyzed using the Kaplan-Meier method. From the total, 98 patients (11.6%) succumbed, with a majority (80/98) within a month post-infection. C-reactive protein, prealbumin, and CP ratio were all associated with all-cause mortality in the crude model. After adjusting for other confounding factors, the CP ratio remained an independent risk factor for all-cause mortality (HR 1.97; 95% CI 1.07-3.63;  = 0.029). In addition, we also found that the CP ratio has better discriminatory ability, than the C-reactive protein to albumin ratio (areas under the curve; 0.84 vs. 0.80; Z-test;  = 0.001). This study underscores that CP ratio substantially influence the mortality rates in hemodialysis patients following Omicron infection. Careful monitoring and consideration of the CP ratio could inform more effective patient management strategies, potentially leading to reduced mortality rates in this vulnerable group.

There is ample evidence to suggest that patients infected with SARS-CoV-2 Omicron variant may experience liver dysfunction. However, the impact of pre-infection liver function on postinfection mortality rates remains inadequately researched. Data from 847 hemodialysis (HD) patients, diagnosed with Omicron across six HD centers between December 2022 and February 2023, were analyzed. Initial liver function assessments were conducted, following which patients were monitored for mortality outcomes. The stepwise multivariable Cox regression analysis and receiver operating characteristic (ROC) curves were utilized to identify the predictors of mortality. From the total, 98 patients (11.6%) succumbed, with a majority (80/98) within a month postinfection. The deceased patients were observed to be mostly older males with an increased prevalence of diabetes and tumors, signifying higher AST and C-reactive protein levels. These patients also exhibited lower hemoglobin, albumin, and prealbumin levels. An elevated AST [per 1 IU increment; HR 1.04 (95% CI 1-1.04),  = 0.026], AST/ALT ratio [per 1 increment; HR 1.52 (95% CI 1.27-2.36),  = 0.004], and reduced prealbumin [per 10 mg/L increment; HR 0.93 (95% CI 0.9-0.96),  < 0.001] were discovered to be independent indicators of an increased mortality risk. Notably, AST, AST/ALT ratio, and prealbumin proved significant predictors of mortality (AUC values were 0.59, 0.65, and 0.79 respectively). This study underscores that pre-infection liver function, specifically AST, AST/ALT ratio, and prealbumin levels, substantially influence the mortality rates in HD patients following Omicron infection. Therefore, careful consideration of these liver function parameters could guide superior patient management strategies and potentially decrease mortality rates within this at-risk population.