Search Results (6,606)

Dynamic knowledge representation in curved manifolds conventionally relies on integer-order Markovian sequence encoders, intrinsically yielding exponential memory decay. This paradigm fails to model the anomalous diffusion and heavy-tailed historical dependencies inherent in complex evolutionary networks and dense physical environments. This manuscript proposes the Fractional–Temporal Lorentz Graph Convolutional Network (FTL-GCN), formalizing temporal evolution as a continuous fractional geometric flow explicitly defined on the tangent bundle of the Lorentz manifold. Analytical derivations demonstrate that the discrete Grünwald–Letnikov memory kernel establishes a non-exponential, power-law lower bound for historical state retention, preventing topological manifold collapse over extended temporal horizons. Empirical evaluations demonstrate that FTL-GCN achieves competitive forecasting accuracy against the latest 2025–2026 state-of-the-art discrete models within specific temporal windows, while uniquely mitigating predictive degradation by up to 52% in long-horizon dependency stress tests and maintaining sub-millisecond latency for physical control. The architecture is subsequently deployed within an in silico biophysical simulation for autonomous micro–nano robotic navigation in the Tumor Microenvironment (TME). By establishing a physical-mathematical structural analogy—mapping the empirical fractional viscoelasticity of the extracellular matrix to the cognitive network’s fractional derivative order—FTL-GCN sustains continuous-space navigation policies in dense anomalous environments where standard integer-order models experience mechanical slip. Full article

While diabetic retinal disease (DRD) has classically been viewed as a microvascular complication, emerging evidence places the photoreceptor at the center of its pathogenesis. Recognizing this central role provides a critical framework for resolving a major clinical paradox in diabetes: why the retina exhibits profound susceptibility to hyperglycemic damage, whereas closely related neural tissues like the brain are mostly spared. In this review, we synthesize the evidence for photoreceptor-driven DRD pathology by evaluating two primary mechanistic paradigms. In the first, hyperglycemia-induced damage to the blood vessels limits perfusion, creating an ischemic environment that selectively devastates tissues dependent on exceptionally high blood flow and energy delivery—specifically, the photoreceptors. In the second paradigm, hyperglycemia induces a direct shift in the metabolic profile of photoreceptors, triggering oxidative stress and dysregulated lipogenesis that subsequently place pathological strain on the local microvasculature. Regardless of whether the initial insult is vascular or neuronal, the photoreceptor remains the critical node of disease progression. Because current and investigational DRD treatments predominantly target downstream vascular consequences, exploring these dual mechanisms highlights an urgent need and a significant opportunity to develop novel therapies that target the photoreceptor to address DRD at its root. Full article

Individuals with diabetes mellitus (DM) experience impaired wound healing, where the healing process is often compromised by a complex, hostile microenvironment characterized by persistent inflammation, high oxidative stress, and dysfunctional angiogenesis. The hyperglycemic environment damages the blood vessels and disturbs the normal hypoxia-induced upregulation of vascular endothelial growth factors, causes poor vascularization and insufficient production of new blood vessels, and leads to impaired perfusion and thickened and dysfunctional capillary basement membranes, which reduce blood flow to the wound, leading to delayed wound healing. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are the main effectors of intercellular communication and have emerged as a potent cell-free strategy for the acceleration of tissue repair. MSC-EVs can be isolated from various adult tissues, but increasing evidence suggests that pla Full article

Background: Glioblastoma (GBM) is characterized by high morbidity and mortality due to its localization and often locally invasive growth. Current treatment options for GBM are limited, with conventional therapies achieving a median survival of only 15 months. Mechanotherapy has been proposed as a new therapeutic strategy in oncology. Low-intensity focused ultrasound (LIFU), a form of mechanotherapy, has demonstrated inhibitory effects on GBM. However, its underlying mechanisms remain poorly understood. The present study aimed to evaluate the therapeutic effects of LIFU on GBM and investigate its mechanisms of action. Methods: Cell viability and proliferation were evaluated using cell counting kit-8, EdU and colony formation assays, while the effects of LIFU on GBM cell apoptosis were evaluated by flow cytometry. Transcriptome sequencing, immunofluorescence, reverse transcription-quantitative polymerase chain reaction, Western blot, bioinformatics analysis, dual-luciferase reporter assay and chromatin immunoprecipitation were used to investigate the molecular mechanisms underlying the effects of LIFU on GBM. The therapeutic efficacy of LIFU was further validated in a subcutaneous xenograft tumor model, in which tumor size, survival rate and immunohistochemical changes were monitored. Results: The results of the present study demonstrated that LIFU exerts anti-GBM effects by activating Piezo1 and modulating the downstream ATF3/PPP1r15a pathway to regulate apoptosis. LIFU therapy holds promise as a new treatment strategy for GBM, with the potential to improve patient prognosis. Conclusions: LIFU suppresses GBM progression through the Piezo1/ATF3/PPP1r15a axis by activating endoplasmic reticulum stress. Full article

The radial heat transfer mechanism of compacted conductors in overhead insulated cables is unclear, and the insulation layer complicates the thermal boundary conditions, limiting the direct applicability of existing ampacity calculation methods. Based on the Morgan model framework, this paper proposes an ampacity calculation method that accounts for the “plastic-then-elastic” deformation characteristics of compacted conductors. Material plastic flow and elastic deformation of the substrate are incorporated to refine the formulations for interlayer thermal contact conductance and thin-layer air gap thickness, while the equivalent distance of air voids is corrected using the fill factor. An iterative convergence procedure for the insulation outer surface temperature is established to accurately evaluate conductor Joule losses. Validated by wind tunnel tests on JKLGYJ 240/30 cables, the proposed method yields a radial temperature difference of 2.41 °C, closely matching the measured 2.6 °C, with an error of 7.4% compared to 13.5% for the conventional Morgan model. Parametric analysis reveals that equivalent radial thermal conductivity is independent of external environmental factors. Conductor stress has a negligible effect on the ampacity (variation < 0.1%). Under low wind speeds (0–5 m/s), the ampacity increases substantially with wind speed. Full article

Multi-output, single-switch, hard-switched Pulse-Width Modulated (PWM) converters suffer from high switching losses, which strictly limit their power density. To significantly reduce these losses, this work proposes a novel family of non-isolated multi-output DC-DC converters based on a quasi-resonant, single-switch cell operating in the megahertz (MHz) range. Sixteen configurations are derived to enhance power density and minimize component stress. A comprehensive analysis derives the fundamental analytical expressions for operation, switching conditions, and power flow. These expressions form the basis of a design tool that facilitates parametric component selection and optimization. The developed tool calculates voltage and current stresses, alongside power losses, using RMS current analysis and user-defined parameters such as ESR and semiconductor non-idealities. Finally, experimental results from prototypes operating at approximately 1 MHz in both full-wave and half-wave modes, with step-up and step-down capabilities, confirm the accuracy of the analytical design tool and the simulation model. Full article

Riverbed dynamics and erosion processes remain an important research issue, particularly under increasing anthropogenic pressure on river systems. This study investigates long-term channel changes and bed-incision processes in selected Carpathian rivers—the Skawa, Raba, and Dunajec—with particular emphasis on bridge-affected reaches. The analysis combined hydrological and geomorphological data with one-dimensional MIKE 11 hydraulic modelling to assess local changes in flow parameters and indicators of erosion potential under Q1% flow conditions. In the analysed cross-sections, riverbed lowering ranged from 1.0 to more than 3.5 m over the observation period, confirming the occurrence of long-term channel degradation. The results indicate that this process was primarily related to historical gravel extraction and channel regulation, whereas bridges mainly modified local hydraulic conditions. In the vicinity of bridge structures, flow velocity increased to as much as 7.31 m/s, and local changes in water surface elevation reached 0.90 m, indicating increased susceptibility to local scour near piers and abutments. The modelling also showed marked local increases in bed shear stress. At the same time, the results do not support the conclusion that bridges are the primary cause of systemic erosion at the scale of entire river reaches. This research contributes to sustainable development because it provides the knowledge needed for better management of rivers and bridge infrastructure in a way that is environmentally, socially, and economically safe: it shows that long-term riverbed degradation results mainly from earlier anthropogenic transformations, such as aggregate extraction and river regulation, while bridges primarily alter local flow conditions and may increase the risk of erosion around piers and abutments. Full article

Conventional wiped-film molecular distillers(WFMDs) often show limited hydrodynamic renewal and mixing when processing high-viscosity materials because of liquid pooling and weak secondary flow. This study investigates a novel grooved scraper design for a wiped-film molecular distiller handling an ethylene glycol/glycerol mixture (42.0 mol% ethylene glycol; density 1196.0 kg/m³; dynamic viscosity 0.222 Pa·s), used here as a representative high-viscosity, heat-sensitive system. Three-dimensional multiphase CFD simulations were performed to examine the combined effects of groove width (2.0–10.0 mm) and scraper tip angle (30–75°) on flow behavior. The results show that a groove width of 7.0 mm increases vorticity gain by 9% and wall shear stress gain by 20% relative to the inline scraper baseline. The grooved geometry generates periodic shear disturbances, promotes radial secondary flow, and strengthens turbulent mixing. A balance between radial mixing enhancement and axial transport continuity is required. Among the tested angles, a tip included angle of 45° produces the highest average vorticity magnitude and more coherent vortex structures. These findings clarify the hydrodynamic regulation mechanism of scraper micro-geometry and support its use as a process-intensification strategy for distiller parameter selection. Full article

Bingham fluids, also called Bingham plastics, are used in different industries including the production of food, pharmaceuticals, household products, construction and oil and gas drilling. The behavior of Bingham fluids is viscous above a critical shear stress and rigid-body below the threshold stress value. Knowledge of the size of the entrance region has several applications including hemodynamics and microfluidics. A model for steady Bingham fluid flow in the entrance region between parallel plates is developed using the inlet-filled region concept. A boundary layer model is used to solve the fluid flow dynamics in the inlet region up to the point where the critical shear stress is reached at the edge of the boundary layer. Beyond that point, the boundary layer does not grow, while the velocity profile keeps readjusting in the filled region to asymptotically reach the fully developed flow. The results include boundary layer thickness profiles, dimensionless pressure drop, centerline velocity, friction factor and inlet and entrance region sizes as functions of the Bingham number. The results are validated against the results for the Newtonian fluid case (Bingham fluid yield stress equal to zero) and CFD results, using the finite element method, for nonzero Bingham numbers. In addition, the results are found to asymptotically reach the fully developed flow values for the general Bingham fluid flow case. The effects of the Bingham number are addressed and compared with the literature. The present model is largely analytical, requiring minor numerical tasks. Full article

Aortic arch aneurysms are uncommon but clinically significant due to their rapid growth and increasing rupture risk. Analyzing flow changes associated with aneurysm enlargement is essential for understanding mechanisms of disease progression. However, computational studies focusing on the aortic arch aneurysm remain limited. In this study, computational fluid dynamics (CFD) simulations were conducted under pulsatile flow conditions to investigate flow characteristics across different aneurysm sizes. A patient-specific aortic geometry was reconstructed and modified to generate three idealized aneurysm models with diameters of 45, 55, and 65 mm, along with a healthy reference model. Key hemodynamic parameters, including velocity distribution, flow recirculation, wall shear stress (WSS), oscillatory shear index (OSI) and helicity, were analyzed. The results demonstrated that increasing aneurysm size significantly disrupts normal flow patterns, leading to reduced flow velocities and progressively enhanced recirculation zones, particularly during the deceleration phase of the cardiac cycle. Enlarged aneurysms also exhibited consistently low WSS, elevated OSI, and disrupted helical flow patterns along the vessel walls. These adverse hemodynamic conditions are associated with intraluminal thrombus (ILT) formation, localized wall thinning, and increased risk of dissection or rupture. Overall, this study highlights the critical role of aneurysm size in shaping aortic arch hemodynamics and provides a computational framework for assessing disease progression and rupture potential. Full article

This paper presents the results of numerical calculation of steady-state magnetorheological fluid flow in the gap of an eccentric seal subjected to an external radial magnetic field. A coupled problem combining magnetic field analysis and laminar viscoplastic flow with Bingham rheology is solved to obtain pressure and velocity distributions within the seal gap, from which the hydrodynamic reaction forces of the fluid film and the rotor friction torque are determined. A parametric study was conducted in the ranges of rotor angular velocity ω = 100–400 rad/s, relative eccentricity ε = 0–0.9, and magnetic flux density B₀ = 0–0.5 T at the pressure differential Δp = 2 atm. Analysis of the results shows that increasing the magnetic flux density from 0 to 0.5 T leads to an increase in the seal reaction force from 12 N to 642 N and the friction torque from 0.35 N·m to 11.23 N·m. The most intensive growth of both characteristics is observed in the range B₀ = 0–0.3 T, beyond which saturation occurs as the MRF yield stress reaches its plateau value. An optimal control range of B₀ = 0.1–0.2 T was determined, ensuring maximum seal energetic efficiency as quantified by the load capacity-to-friction torque ratio, which is maximized at 70 N/(N·m). Based on the obtained results, the consequences of using magnetorheological seals on the performance of the rotor system are discussed, including the analysis of the sealing effect on rotor-dynamic stability. Within the proposed optimal range, it is shown that an increase in magnetic flux density leads to a sign reversal of the horizontal reaction F₂, while the monotonic growth of the ratio |F₂|/F₁ indicates an intensification of cross-coupling and a corresponding reduction in the rotordynamic stability margin at higher values of B₀. Full article

Background/Objectives: Snow Chrysanthemum (Coreopsis tinctoria Nutt.), a traditional medicinal and edible plant rich in flavonoids (TFSC) with antihypertensive and neuroprotective activities, has unclear effects and mechanisms on vascular dementia (VaD) comorbid with hypertension, a key risk factor accelerating VaD. This study aimed to investigate TFSC’s ameliorative effects on cognitive impairment in hypertensive VaD rats and elucidate its holistic therapeutic mechanisms. Methods: Spontaneously hypertensive rats (SHRs) with unilateral common carotid artery ligation were used to establish the hypertensive VaD model. TFSC was intragastrically administered for 11 weeks. Systolic blood pressure (BP) and cerebral blood flow (CBF) were monitored; cognitive function was assessed via open field, novel object recognition and Morris water maze tests. Histopathological changes were evaluated by H&E and Nissl staining, serum oxidative stress and inflammatory markers were measured, and hippocampal transcriptome sequencing plus RT-qPCR was performed to identify key pathways and genes. Results: The chemical profile of TFSC was characterized, showing a total flavonoid content of 84.96%; 49 compounds were identified, 39 of which were flavonoids. TFSC reduced BP, improved CBF, alleviated cognitive dysfunction and neuronal damage, enhanced antioxidant capacity (increased SOD, CAT, GSH; decreased ROS), and exerted anti-inflammatory effects (reduced TNF-α, IL-1β, IL-6, Ang-II). It modulated multiple pathways, with the PI3K-Akt and MAPK pathways enriched, and validated key differentially expressed genes. Conclusions: This study provides preliminary evidence for the holistic therapeutic potential of TFSC against hypertensive VaD. With integrated vascular regulatory and neuroprotective effects, TFSC serves as a promising candidate for VaD by targeting both vascular risk factors and neuropathological damage. Full article

The objective of this study was to compare the protective effects of native and nanostructured quercetin on the initiation of oxidative stress in human keratinocytes exposed to tert-butyl hydroperoxide (tBHP). Quercetin was encapsulated within gelatin-based nanocontainers, forming nanoparticles with diameters ranging from 140 to 180 nm. Two formulations were prepared: uncoated gelatin nanoparticles (NP1) and gelatin nanoparticles coated with a shell composed of dextran sulfate and a chitosan–dextran copolymer (NP2). Cell viability was assessed using PrestoBlue™ reagent. Apoptotic and necrotic cell populations were identified via flow cytometry using an Annexin V-FITC/PI staining kit. DNA damage was evaluated using the comet assay. The results demonstrate that gelatin nanoparticles effectively encapsulate quercetin, and the nanostructured form enables its application in aqueous suspensions without compromising its antioxidant, gene-protective, and cytoprotective effects under conditions of cellular oxidative stress. These findings suggest that gelatin nanoparticles are suitable carriers for quercetin, owing to their high aqueous solubility, which may improve its potential for oral or topical delivery. Full article

Large retail developments act as strong trip attractors and can substantially alter traffic demand patterns at adjacent urban intersections. This paper analyzes the operational impacts of a major shopping center on two nearby signalized intersections in Novi Sad, Serbia, and evaluates the effects of reconstructing one of them into a turbo roundabout. Traffic data collected before and after the shopping center opening, as well as before and after the intersection reconstruction, were analyzed using calibrated and validated microsimulation models. Results indicate that peak-hour traffic volumes increased by 8.38% and 6.96% at the analyzed intersections following the shopping center opening, leading to increased delays and operational stress under fixed signal control, particularly under unbalanced turning demands. The conversion of the three-leg signalized intersection into a turbo roundabout resulted in substantial reductions in average delay and improvements in level of service under identical traffic demand conditions, mainly due to the elimination of left-turn signal phases and reduced conflict interactions. The findings confirm that turbo roundabouts can provide significant operational benefits in dense urban environments characterized by strong directional flows; however, their effectiveness is highly context-dependent and influenced by traffic composition and geometric constraints. The results are interpreted as representative of typical weekday peak conditions, acknowledging data and temporal limitations. Full article

Low-temperature stress severely restricts the engineering application of anaerobic ammonia oxidation (anammox) technology in municipal mainstream wastewater treatment, leading to its slower large-scale implementation relative to industrial wastewater and reject water treatments. The inhibitory effects of low temperatures on the anammox process cannot be merely ascribed to conventional microbial metabolic responses. Elucidating the specific mechanisms underlying low-temperature impacts on anammox bacteria is therefore critical for formulating targeted mitigation strategies. In this study, a meta-analysis was performed to compare the response patterns of specific anammox activity (SAA) and nitrogen removal rate (NRR) to temperature variations. SAA declines gradually with decreasing temperature, while NRR displays a more dramatic and stepwise reduction. The T₅₀ values (temperature corresponding to 50% of the performance at 30 °C) for these two parameters are 20 °C and 15 °C, respectively. Low-temperature inhibition of anammox is a multifaceted process, encompassing direct physiological disturbances to individual anammox cells and impaired nitrite bioavailability within the microbial community. To address these temperature-related bottlenecks, a conceptual hybrid nitrogen removal system was rationally optimized by integrating conventional strategies with an innovative split-flow influent regulation strategy. This hybrid system is anticipated to enhance the stability and treatment efficiency of anammox under low-temperature conditions, thus facilitating its broader engineering application in cold climate regions. Full article