Search Results (1,013)

In the clinical context of the new medical concept of diseases related to the Major Histocompatibility Complex class I (MHC-I-opathy), contrasting data are available on the possible association among HLA-B*51, Behcet’s disease (BD), and spondyloarthritis (SpA). The aim of this retrospective study on a cohort of HLA-B*51-positive patients who were clinically observed for almost 5 years is primarily to evaluate which classification criteria they satisfy among BD, axial (ax) or peripheral (p) SpA, and psoriatic arthritis (PsA). Furthermore, we characterized the possible impact of different arthritis phenotypes on the most frequent extra-articular clinical manifestations in BD, ax-SpA, p-SpA, and PsA. A comparison with HLA-B*51-negative patients (matched with HLA-B*51-positive patients for age, gender, and diagnosis, by mean propensity score) was also performed to evaluate the true impact on clinical manifestations of HLA-B*51. We conducted a monocentric retrospective study from 2013 to 2025. The inclusion criteria were HLA-B*51 positivity, the availability of the entire MHC-I class test, and rheumatological clinical follow-up of at least 5 years. The exclusion criterion was positivity for clinically important MCH-I loci other than HLA-B*51. A total of 105 patients met the inclusion criteria in an average clinical observation period of 8.4 ± 2.9 years. All patients were Apulian and were HLA-B* 51 positive. During the follow-up, 32 patients (31%) met the BD criteria, 17 (16%) met the PsA criteria, 25 (24%) met the p-SpA criteria, and 13 (12%) met the ax-SpA criteria. Of note, 16% and 34% of BD patients met the ax-SpA and p-SpA ASAS criteria, respectively. Prevalent articular phenotypes in this HLA-B*51 cluster of patients are a polyarticular pattern and enthesis involvement in all disease groups. In BD patients, axial involvement was associated with a significantly higher percentage of neurological manifestations (40% vs. 7%, p = 0.043) and inflammatory bowel disease (IBD) (100% vs. 15%, p = 0.0001), compared to patients with exclusive peripheral joint involvement. This latest data on IBD remains significant, even in comparison with HLA-B*51 negative patients (33%; p = 0.035). In the p-SpA group, a significantly higher rate of uveitis (28%) was observed compared to both ax-SpA with HLA-B*51-positive (0%, p = 0.035) and p-SpA with HLA-B*51-negative patients (4%, p = 0.030). A high percentage of multi-drug failures was highlighted in patients with PsA (60%) and p-SpA (40%). This study provides new data on the association between HLA-B*51 and the onset of BD and/or SpA or PsA, and its possible impact on extra-articular manifestations. We confirm the higher prevalence of the peripheral articular phenotype in BD, but we also highlight a specific association between the rarer axial involvement and gastrointestinal involvement in HLA-B*51 patients. In SpA, the peripheral articular phenotype appears to be associated with a higher occurrence of uveitis in the presence of HLA-B*51. Full article

Tuned mass dampers (TMDs) are commonly used to reduce excessive vibrations in engineering structures. Although their vibration control performance has been widely studied, the reliability of TMD-equipped structures under stochastic excitations has not been sufficiently investigated. In practical applications, random loads and system uncertainties may significantly affect structural safety, and an efficient evaluation of failure probability remains a challenging task. Thus, the applications of these methods are greatly limited in vibration control. In this work, the structural reliability of systems equipped with TMDs is analyzed by adopting the first-passage time (FPT) as the failure criterion. Numerical investigations are performed on continuous beam models with TMDs under different types of stochastic excitation. In addition, an experimental study on a two-story steel frame structure is conducted to further examine the reliability performance of TMD-controlled systems. To reduce the computational cost associated with Monte Carlo simulation, a data-driven classification method is employed to approximate the failure domain based on a limited number of samples. The results indicate that the proposed approach enables accurate reliability estimation with a substantial reduction in computational cost, making it suitable for large-scale reliability analysis of vibration-controlled structures under stochastic excitation. The experimental results further demonstrate the applicability of the proposed reliability assessment method for practical vibration control problems. Full article

Background: Inhaled therapy is the mainstay of asthma management, yet many patients are prescribed pressurized metered-dose inhalers (pMDIs) with valved holding chambers (VHCs) based on a presumed low inspiratory capacity, often without objective measurement. The USE-DPI study aimed to determine how many of these patients can generate sufficient peak inspiratory flow (PIF) to use a dry powder inhaler (DPI). Methods: This multicenter, observational, cross-sectional study included 346 patients with asthma treated with pMDI and VHC. PIF was measured using the In-Check Dial at two resistance settings (R2 and R4). The primary outcome was the proportion of patients achieving PIF ≥ 30 L/min. Results: Almost all patients reached the 30 L/min threshold (99.4% at R2 and 98.7% at R4). Using a higher threshold of 60 L/min (R2), 76.1% met this criterion. Lower PIF (<60 L/min) was associated with older age, reduced lung function (FEV1 ≤ 80% predicted), and poorer asthma control. No significant variables were associated with failure to reach 30 L/min. Conclusions: Most patients using pMDI with VHC can generate sufficient inspiratory flow for medium- to high-resistance DPIs. Objective PIF assessment may help guide inhaler selection, although its clinical impact requires further study. Full article

Existing methods for assessing the stability of deep tunnel face rarely account for the weakening effect of rock mass parameters caused by excavation disturbance. This paper employs a vertical discretization method to divide the rigid failure body into vertical strip elements with fixed horizontal widths. By considering the weakening effect of rock mass parameters, a stability analysis model for the tunnel face is established. The equivalent cohesion and internal friction angle of the rock mass are obtained using the Hoek–Brown criterion and the equivalent Mohr–Coulomb transformation. Combined with the disturbance weakening factor, these yield the equivalent rock mass parameters after disturbance. Stability is solved using limit analysis and the principle of virtual power. The accuracy of the established model is verified through numerical simulation, demonstrating that the proposed analytical approach requires only about 90 s per run compared to approximately 7 h for 3D numerical models. The results indicate that the importance of parameters, in descending order under the specified reference conditions for deep-buried tunnels, is GSI > D_r > h₁ > m_i, where GSI play a dominant role. Excavation disturbance significantly reduces rock mass strength numerically. Assessing GSI and controlling the blasting disturbance are key to ensuring the stability of deep tunnels. Full article

Pile-supported geosynthetic-reinforced embankments, as effective foundation improvements, are being used increasingly often in the construction of highway and railway engineering at present. The geosynthetic-reinforced load transfer platform in the horizontal direction was simulated to the thin plate, and then the differential equation of the curved surface and the nonlinear foundation model were used to solve the analytical expression of the post-construction settlement of the reinforced area, and the engineering example was used to verify it. Furthermore, a finite element model was developed to simulate the settlement. The analysis utilized a static general step and incorporated a linear elastic–perfectly plastic model with the Mohr–Coulomb failure criterion. The numerical result of 19.7 mm was consistent with the theoretical prediction of 20.1 mm, demonstrating a mere 2.0% relative error and substantiating the validity and accuracy of the theoretical model. The analysis examined how bending stiffness, the subgrade reaction coefficient, pile spacing, and embankment height affect post-construction settlement. The results demonstrate that the settlement increases with larger pile spacings or lower values of the subgrade reaction coefficient and bending stiffness. Notably, the settlement increases with embankment height only until a critical height—calculated from the bearing capacity of the inter-pile soil—is exceeded. Based on this, it was found that the subgrade reaction coefficient was identified as the most influential parameter, followed by pile spacing and then bending stiffness. These findings lead to practical recommendations for engineering practice. Full article

Coal is inherently soft, characterized by well-developed cleat systems, low strength, and significant anisotropy. Existing models that treat coal as a continuous medium or consider only a single plane of weakness fail to capture the synergistic effects of multiple weaknesses on wellbore instability. This study addresses this gap by integrating the strength criteria of weakness planes with wellbore stress theory. First, in situ stresses were transformed into the coordinate system of the weakness planes to derive the acting stress components. A strength criterion incorporating multiple structural planes—accounting for the coal matrix, bedding, face cleats, and butt cleats—was then applied to establish a coupled wellbore stability criterion. A corresponding collapse pressure program was developed using Visual Basic to analyze the effects of stress state, wellbore trajectory, and weakness orientation. The results show that the presence of multiple weakness planes significantly increases the sensitivity of wellbore stability to trajectory. Drilling parallel to the direction of minimum horizontal stress minimizes shear stress and collapse pressure, whereas drilling at high angles or parallel to the maximum horizontal stress activates the weakness planes, leading to a sharp increase in collapse pressure. The presence of these weaknesses results in a highly non-uniform and direction-dependent collapse pressure distribution, with their synergistic interactions further exacerbating the risk of localized failure. Full article

Harmonic reducers exhibit non-stationary and phase-dependent degradation behavior during long-term service, challenging the ability of classical stochastic degradation models to accurately assess reliability. To address phase-dependent differences in degradation behavior, this paper proposes a reliability assessment model based on a two-phase hybrid stochastic degradation process. In the proposed framework, the Wiener process is employed to characterize early-phase gradual degradation dominated by stochastic fluctuations, while the Inverse Gaussian process is used to describe later-phase monotonically accelerated degradation driven by cumulative damage. The framework allows for sample-level variability in transition times to more realistically capture individual degradation behavior. The Schwarz Information Criterion is also adopted to detect change points. Maximum likelihood estimation is performed for model parameter inference, and analytical expressions for the reliability function, cumulative distribution function, and probability density function are derived. Numerical results indicate that a change point exists for each tested product and that the proposed model achieves the best goodness of fit among the considered candidates, demonstrating its superiority in capturing phase-dependent characteristics of harmonic reducer degradation. In terms of reliability assessment bias, the proposed model (0.06%) significantly outperforms the Wiener degradation model (32%) and the IG degradation model (9.9%). These results further confirm that, under an identical failure threshold, the proposed approach yields more accurate and realistic reliability assessment outcomes. Full article

The dominant agri-food system’s well-documented failures—biodiversity loss, deepening rural inequalities, and the erosion of small-scale farming livelihoods—have elevated SSE initiatives and social innovation in the agri-food sector and bioeconomy from a niche policy concern to a structural priority. This paper examines how SSE arrangements drive meaningful transformation in agri-food chains while advancing sustainable development at local and regional scales. Through a narrative review of interdisciplinary peer-reviewed literature and key institutional sources, the paper synthesizes evidence that SSE initiatives generate transformation through three interconnected mechanisms: (a) the reconfiguration of governance structures; (b) the deepening of producer–consumer relationships through spatial proximity and relational transparency; and (c) the more equitable redistribution of value across agri-food territories. These findings suggest that place-based SSE models occupy a central—rather than peripheral—role in sustainability transitions and local development. The paper presents a structured analytical framework linking SSE practices to agri-food chain transformation and develops nine concrete policy implications for scaling and sustaining SSE innovations through coordinated collaboration among public, private, and social economy stakeholders. The findings contribute to a sharper understanding of the conditions under which SSE-driven models can foster sustainable, socially inclusive, and community-oriented agri-food systems and of why the solidarity dimension, rather than organisational form alone, is the decisive criterion for identifying genuinely transformative initiatives. Full article

This study proposes an innovative structural wall system and evaluates its compressive performance. The wall consists of GLPB manufactured using laminated bonding (along the grain direction) and assembled using a staggered interlocking masonry method. Two key geometric parameters controlling the mechanical response of the GLPB wall—the slenderness ratio (β) and the eccentricity (e)—were selected as the primary design variables. Using a combined experimental and numerical approach, the study systematically investigated the compressive mechanical behavior and performance evolution of the wall, including compressive strength and deformation behavior. Through axial and eccentric compression tests, six sets of specimens with varying geometric parameters β and e were analyzed, yielding relevant data and characteristics regarding failure modes, ultimate load-carrying capacity, load–displacement response, crack resistance, and wall deformation. To further characterize the compressive mechanical performance of GLPB walls, a refined nonlinear finite element model was developed in ABAQUS (version 2020). This model incorporates the anisotropic constitutive behavior of wood, the Hill yield criterion, and the mechanical interactions at the interlocking and bonding interfaces. The study indicates that the average compressive strength of GLPB walls is 2.63 MPa, with a crack-to-failure load ratio ranging from 0.68 to 0.83. GLPB walls demonstrate comparable load-bearing capacity. The total axial vertical strain ranges from 0.033 to 0.041, indicating that the walls possess good deformation capacity. Based on Chinese masonry design standards and experimental evidence, a preliminary predictive formula for the load-bearing capacity of this wall was derived. A comparison of the aforementioned experimental measurements with simulation results showed errors of less than 10%, verifying the model’s validity and accuracy. Numerical simulation can, to a certain extent, compensate for the limitations of experimental methods in capturing internal mechanical states. Full article

This study examines how assessments of coastal extreme sea levels depend on the separability and reconstructability of the astronomical tide in hourly sea-level records. Using a global tide-gauge network, it proposes an ensemble-learning correction framework that integrates a physical-baseline threshold with multi-criteria consistency testing to determine whether machine-learning enhancement is genuinely effective across stations and time windows. The analysis uses hourly records from 528 UHSLC tide gauges, with 31-day short sequences used to reconstruct 180-day sea-level variability. Taking the physical tidal model as the baseline, residuals are corrected using Extremely Randomized Trees, Random Forest, and Gradient Boosting. To avoid false improvement driven solely by error reduction, a hierarchical decision framework is established. Baseline model quality is first screened using NSE and the coefficient of determination, after which mathematical artefacts are identified through diagnostics of peak suppression and variance shrinkage. A five-level classification is then derived from the convergent evidence of twelve performance metrics and four statistical significance tests. The results show a consistent global pattern across all three algorithms. Approximately 57% of stations meet the criterion for genuine improvement, whereas about 42% are associated with an unreliable physical baseline, indicating that the dominant source of failure arises not from the ensemble-learning algorithms themselves, but from spatially varying limitations in the underlying physical baseline. Spatially, the credibility of machine-learning correction is strongly conditioned by baseline quality: stations with effective correction are more continuous along the eastern North Atlantic and European coasts, whereas stations with ineffective correction are more concentrated in the Gulf of Mexico, the Caribbean, and the marginal seas and archipelagic regions of the western Pacific. These results indicate that the observed spatial heterogeneity primarily reflects geographically varying physical and dynamical conditions that control baseline reliability and residual learnability, rather than a standalone difference in the intrinsic capability of ensemble learning itself. Full article

Composite materials have traditionally been employed in the aerospace sector due to their ability to withstand highly demanding service conditions. In recent years, their application has expanded significantly into other engineering domains, including wind energy, shipbuilding, and the automotive industry. The design of composite structures often involves geometric discontinuities, such as cut-outs for access or fastener holes for mechanical joining, which typically become critical regions under load. Consequently, the stress concentrations induced by notches represent a major concern, as they can lead to substantial reductions in strength compared with unnotched laminates. A comprehensive understanding of the behaviour of notched specimens is therefore essential for the design of complex composite assemblies, where components are commonly joined using bolts and rivets. The objective of this study is to examine the tensile response and notch sensitivity of carbon fibre-reinforced polymer (CFRP) laminates with different stacking sequences, through a comparative analysis of unnotched and open-hole specimens. A central circular hole was introduced to reproduce the geometric discontinuities frequently encountered in structural applications, enabling a detailed assessment of stress concentration effects. The experimental results indicate that unidirectional laminates exhibit the highest sensitivity to notches, whereas quasi-isotropic configurations among the multidirectional laminates display the most pronounced reduction in strength, approaching 50%. Moreover, the Point Stress Criterion (PSC) and the Average Stress Criterion (ASC) were employed to determine the characteristic lengths of the specimens, revealing significant differences among the values obtained for each lay-up configuration. Overall, the findings highlight the strong influence of stacking sequence on the mechanical response of notched CFRP laminates and underscore the need to further refine existing failure criteria to accommodate novel laminate architectures, including Bouligand-type helicoidal bioinspired stacking sequences. Full article

This study investigates the interaction between the skin and stiffeners under tension and the structural failure mechanisms of aluminum alloy stiffened panels after battle damage, employing an integrated approach of experimental testing and numerical simulation. The variation in the residual strength of the stiffened panels with the characteristics of ruptures was explored, and an assessment method for residual strength was proposed based on the net-section failure criterion. The results indicate that the residual strength of the stiffened panels is closely related to the location and size of the rupture. For panels with ruptures of equal area, the residual strength is lowest for those with web damage, followed by those with flange damage, and highest for those with skin damage only. By employing an area-based conversion method, the three-dimensional stiffened panel was simplified to a two-dimensional plate. A stress averaging coefficient was introduced for large eccentric ruptures, while a conversion factor was applied for small eccentric ruptures to modify the residual strength assessment. The results demonstrate high accuracy. This study provides an efficient and precise method for evaluating the residual strength of damaged stiffened panels, offering a theoretical basis for aircraft battle damage repair. Full article

In marine renewable energy applications, offshore steel pipelines are subjected to complex combined loads during installation and operation, leading to significant plastic deformation and potential catastrophic fracture. To accurately characterize pipeline fracture failure, this study develops an enhanced failure assessment framework based on the Modified Mohr–Coulomb (MMC) criterion, integrating experimental parameter evaluation with numerical simulation for in-service offshore pipelines. The key parameters of the MMC model were determined directly from in-service pipeline samples to account for operational degradation. First, the plastic parameters were obtained by fitting the Swift hardening law to uniaxial tensile tests. Fracture parameters were then calibrated using a suite of five notched tensile specimens. Mesh sensitivity was analyzed using CT experiments to establish a suitable mesh size for the MMC-based damage model, enabling precise characterization of crack evolution from initiation to final tearing. Unlike prior applications, this framework is employed to investigate the response of X80 pipelines under combined tension, bending, and external pressure loading. Three-dimensional finite element models were developed to systematically analyze the stress–strain response, moment–curvature behavior, and evolution of hoop stress distribution. Results show that while the failure stress remains relatively stable under varying external pressure, both the critical strain and critical curvature increase markedly with pressure, by up to 20.9%. They also reveal a pronounced hierarchy in the influence of crack geometry on the failure behavior. Crack depth dominates failure sensitivity, affecting critical strain and pressure response far more than crack width or length. The reduction in failure stress for deep cracks under 12 MPa external pressure is over three times greater than for shallow cracks. In contrast, variations in crack length exert the most negligible influence on failure characteristics, with observed discrepancies of less than 6%. Overall, this research provides a high-precision failure prediction framework for in-service pipelines by quantitatively analyzing failure behavior under combined loads. It effectively characterizes failure evolution paths that differ from design conditions and dynamically tracks the residual fracture resistance after time-dependent degradation, offering a fundamental reference for the reliability assessment of pipelines in complex marine environments. Full article

Repeated impact loading can induce progressive fatigue delamination in composite laminates, in which both damage accumulation and strain-rate sensitivity of the interlaminar interface play important roles. In this work, an adopted rate-dependent fatigue cohesive formulation is extended to a three-dimensional framework for simulating interlaminar delamination in composite laminates subjected to repeated impact. The constitutive formulation incorporates separation-rate-dependent critical tractions and fracture toughness together with cumulative fatigue damage, enabling a unified description of dynamic rate effects and progressive interface degradation. A time-incremental algorithm is developed and implemented in ABAQUS 2020/Explicit through a user-defined cohesive element subroutine (VUEL). The cohesive formulation is further coupled with the Hashin intralaminar failure criterion to represent the interaction between interlaminar delamination and intralaminar damage. Numerical simulations are conducted for composite laminates with three structural configurations—conventional, drop-off, and wrapped drop-off—to systematically examine the influence of rate dependence on fatigue delamination under repeated impact. The results show that the developed framework captures the progressive evolution of delamination and impact response under repeated impact and indicate that the sensitivity to rate-dependent interlayer properties depends on both laminate configuration and impact velocity. The present study provides a feasible computational framework for the comparative simulation and assessment of fatigue delamination under repeated impact and offers numerical insight into the role of structural configuration and interfacial rate dependence in composite laminates. Full article

This study investigated the failure mechanism and load-bearing capacity of ultra-high-performance concrete (UHPC) columns confined with high-strength spiral stirrups under axial compression. Based on tests of 75 specimens, a structural stability analysis method was employed to convert multi-point strain measurements into the normalized generalized strain energy density (E_j,norm). The mutation point (Point U) on the E_j,norm-F_j curve, identified via the Mann–Kendall criterion, was proposed as a novel indicator for structural instability and the practical failure load. Parametric analysis showed that increasing the UHPC compressive strength from 100 MPa to 180 MPa raised the failure load by 63%, while increasing the stirrup volumetric ratio from 0.9% to 2.0% yields a further 7.5% increase in the failure load. In contrast, the yield strength of stirrups exerts a negligible influence on the failure load, as the stirrups do not reach their yield strength at the failure load of the concrete columns. A new predictive model for the failure load was developed, which exhibited excellent agreement with test results (mean ratio = 1.000, standard deviation = 0.046, errors within ±13%). The proposed method provided a reliable and stable approach for evaluating the failure load-bearing capacity of confined UHPC columns. The validated predictive model enabled engineers to determine the failure load of confined UHPC columns through simple calculation rather than expensive experimental testing, reducing project costs by 5–10% through optimized material selection and accelerating design timelines by weeks, thereby making UHPC columns more economically competitive for mainstream infrastructure applications. Full article