Search Results (8,335)

Background and Objectives: Obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder associated with increased cardiovascular morbidity and mortality. Continuous positive airway pressure (CPAP) is the standard treatment for OSA; however, its effects on cardiovascular outcomes remain incompletely established. This umbrella review synthesized and critically appraised the evidence regarding the effects of CPAP on surrogate, intermediate, and functional cardiovascular outcomes in adults with OSA. Materials and Methods: An umbrella review of systematic reviews and meta-analyses evaluating CPAP therapy in adults with OSA was conducted. A comprehensive literature search was performed in PubMed, Embase, and the Cochrane Library from database inception to 28 February 2026. Eligible reviews assessed cardiovascular outcomes, including blood pressure, cardiac function, autonomic function, cardiovascular biomarkers, and functional cardiovascular measures. Methodological quality was evaluated using AMSTAR 2, and the certainty of evidence for the main outcomes was assessed using the GRADE framework. Results: Thirty-eight systematic reviews and meta-analyses were included. CPAP therapy was consistently associated with reductions in systolic blood pressure (mean difference [MD] −4.8 mmHg) and diastolic blood pressure (MD −3.0 mmHg), with additional improvements in 24 h ambulatory blood pressure. Favorable effects were also observed for left ventricular ejection fraction (MD 3.27), left ventricular diastolic function (weighted mean difference [WMD] 0.22), and sympathetic nervous system activity, reflected by lower circulating noradrenaline levels (standardized mean difference [SMD] −1.10) in randomized controlled trials. Improvements in BNP/NT-proBNP concentrations and New York Heart Association functional class were reported among patients with heart failure, whereas no significant effect was observed on body mass index. The certainty of evidence ranged from low to moderate, and methodological confidence of the included reviews was predominantly moderate, low, or critically low. Conclusions: CPAP therapy was associated with improvements in several surrogate, intermediate, and functional cardiovascular outcomes in adults with OSA, particularly blood pressure, left ventricular function, and sympathetic activity. However, the certainty of evidence ranged from low to moderate, and substantial heterogeneity and methodological limitations warrant cautious interpretation. Current evidence remains insufficient to demonstrate a consistent reduction in major adverse cardiovascular events or cardiovascular mortality. Further high-quality randomized controlled trials with longer follow-up are needed to clarify the long-term cardiovascular impact of CPAP therapy. Full article

Urtica dioica L. (stinging nettle) is a perennial herb with a long ethnomedicinal history and diverse pharmacological potential. This comprehensive review consolidates current knowledge on its phytochemistry, extraction technologies, bioactivities, and molecular mechanisms. However, recent reviews have generally addressed these aspects separately, and an integrated assessment linking green extraction technologies and phytochemical profiles to molecular mechanisms and gene expression modulation is still lacking. U. dioica contains abundant polyphenols (rutin, quercetin, kaempferol, and chlorogenic acid), sterols (β-sitosterol and stigmasterol), vitamins, carotenoids, and the antiviral lectin Urtica dioica agglutinin (UDA). Advances in green extraction technologies, such as ultrasound-assisted extraction, microwave-assisted extraction (MAE), pressurized liquid extraction, and natural deep eutectic solvent (NADES)-based systems, have significantly improved yield, purity, and environmental sustainability compared to conventional maceration and Soxhlet methods. Comprehensive chromatographic and spectroscopic profiling (HPLC, GC–MS, FTIR, NMR, and LC–MS/MS) has established detailed chemical fingerprints linking bioactive constituents to antioxidant, anti-inflammatory, antimicrobial, and antiviral properties. Mechanistic studies reveal that U. dioica exerts its therapeutic effects through modulation of oxidative stress, inhibition of the NF-κB and COX-2 pathways, enhancement of endogenous antioxidant enzymes, and regulation of apoptotic gene expression. Moreover, NADES–MAE extracts demonstrate potential as sustainable, high-efficacy formulations for nutraceutical and cosmetic applications. Despite extensive preclinical evidence, clinical standardization and dosage optimization remain major challenges. This review underscores U. dioica as a multifunctional medicinal plant with significant promise for next-generation phytotherapeutics and molecular nutrition. Full article

Engine high-altitude simulation tests require establishing a stable low test-chamber pressure across a wide range of operating conditions. Existing studies focus predominantly on the local starting mechanisms—namely, shock-wave swallowing, aerodynamic choking, and boundary-layer separation—of individual ejector or diffuser components, with limited investigation of the coupling among shock evolution, chamber pressure response, starting hysteresis, and diffuser starting thresholds during continuous ejection pressure regulation. To address this gap, a two-dimensional axisymmetric Reynolds-averaged Navier–Stokes model with the standard k-ε turbulence model is employed, encompassing the test chamber, engine nozzle, supersonic diffuser, and annular ejector of a large-scale active-ejection test stand (where an annular ejector actively evacuates the test chamber to simulate high-altitude backpressure). The formation, migration, and stabilization of the shock system are revealed under increasing ejection pressure. Hysteresis characteristics are elucidated by comparing pressure-increasing and pressure-decreasing paths. The non-monotonic relationship between chamber pressure and ejector total pressure ratio under zero-secondary-flow conditions is established. The mechanism governing diffuser starting threshold variation under coupled engine gas and ejection flows is identified. Quantitatively, the ejector starting pressure ratio is found to be approximately 16.78 with a hysteresis width of ~13.6% between the starting and unstarting thresholds, and the diffuser starting threshold scales linearly with the ejector total pressure ratio (R² = 0.976). The results reveal the coupling among shock evolution, hysteresis, chamber pressure response, and diffuser starting thresholds and clarify the dual influence of ejection pressure on both chamber pressure regulation and diffuser starting thresholds. These findings provide a theoretical basis for parameter matching and operational control of high-altitude simulation facilities. Full article

Flexible capacitive sensors for electronic skins and soft robotic systems are expected to provide not only high-pressure sensitivity but also multifunctional sensing capabilities. However, conventional dielectric layer designs often suffer from a trade-off among multiple functionalities. To address this challenge, we developed a flexible sensor featuring a hybrid microstructured functional layer for pressure sensing, distance monitoring, and material identification. The functional layer was a polydimethylsiloxane (PDMS) film embedded with micro-sized sugar particles and patterned with microstructures on its surface. The pressure-sensing performance, such as pressing sensitivity, response time, and hysteresis, was first evaluated. The pressure sensitivity reached 3.55 × 10⁻² kPa⁻¹ at an applied force of 1 N, which is significantly greater than that of the sensor using either a flat PDMS layer or a PDMS film embedded solely with sugar particles. The hybrid microstructured sensor also exhibited superior performance in terms of hysteresis and repeatability. Moreover, the sensor was shown to measure the distance to an object with a sensitivity of 0.023 mm⁻¹. Furthermore, the robust identification of materials with different permittivities was demonstrated using the flexible sensor. Given its multifunctional, non-contact, and high-sensitivity capabilities, this flexible sensor holds significant potential for integration into advanced electronic skins, intelligent soft robotics for tactile object sorting, and human–-machine interfaces. Full article

The phasing out of high-GWP refrigerants and the growing diversity of working fluids used across heat pumps, refrigeration systems, and closed-cycle power applications have made drop-in fluid replacement a question of significant practical interest. Centrifugal compressors are designed around the thermophysical properties of a specific fluid, and the performance penalty is incurred when working fluid is replaced without redesigning the impeller. This study presents a CFD comparison of direct drop-in fluid replacement in a fixed geometry centrifugal compression system. Eight working fluids that span the property range relevant to current drop-in substitutions are evaluated: air, nitrogen, argon, carbon dioxide, R22, R134a, R1234yf, and R1234ze(E). A reference centrifugal impeller was reconstructed in ANSYS BladeGen, meshed in ANSYS TurboGrid using the Automatic Topology and Meshing method, and simulated in ANSYS CFX (2024 R2) as a single periodic passage with Frozen Rotor interfaces and Spalart–Allmaras turbulence closure. Performance maps were generated for each fluid across a range of rotational speeds and mass flow rates, with a common inlet reference condition applied across all cases to isolate the influence of fluid properties from an inlet state. The resulting dataset enables a like-for-like comparison of pressure ratio, efficiency, and shaft power requirement, providing a basis for assessing the aerodynamic implications of drop-in fluid substitution in centrifugal compression systems. Air, nitrogen, argon and carbon dioxide achieved similar peak efficiencies (~88%) and comparable pressure ratios (PR), indicating they can be used as drop-in substitutes without performance loss. Refrigerants R1234yf and R1234ze(E) matched R134a in efficiency (peak ~90%) while offering higher pressure ratios and significantly lower power requirements at peak efficiency. At 20,000 RPM and a mass flow rate of 2 kg/s, compared to a PR of 1.45 for air, nitrogen, carbon dioxide and argon achieved PRs of 1.4, 1.9 and 2.4, respectively. At the same settings, R134a and R1234 refrigerants reached PRs of 5 and 6, respectively. The power requirement was ~8 × 10⁴ W for air and similar fluids, and ~11 × 10⁴ W for refrigerants. Full article

Fractal analysis has been widely applied to characterize the complexity of pore systems in tight sandstone reservoirs. However, fractal parameters derived from different experimental techniques are frequently interpreted without sufficient consideration of their distinct physical meanings. In this study, tight sandstones from the Fuyu Formation in the Songliao Basin were investigated using cast thin sections, scanning electron microscopy, high–pressure mercury intrusion porosimetry, and nuclear magnetic resonance. The objective was to establish a comparative interpretation framework that distinguishes capillary–pressure–controlled geometric fractal dimensions from NMR–derived apparent relaxation–response fractal parameters (ARR fractal parameters). The pore–throat system is dominated by medium– to fine–sized throats, with the dominant pore–throat radii concentrated between 0.05 and 0.15 μm. Mercury–intrusion–derived fractal parameters primarily characterize the geometric heterogeneity of relatively large and fine pore–throat systems, whereas NMR–derived parameters mainly reflect the apparent relaxation response associated with pore–scale fluid occurrence rather than strict geometric complexity. In the present MICP–NMR subset, comparative regression trends indicate that the geometric fractal parameter representing fine pore throats is more responsive to median pore–throat radius and movable–fluid saturation, whereas the NMR–derived apparent relaxation–response parameter associated with longer relaxation times shows a relatively closer relationship with log–transformed permeability. These relationships should be regarded as exploratory response trends rather than universal predictive models. These findings demonstrate that the two types of fractal parameters provide complementary rather than interchangeable information for reservoir evaluation. The proposed comparative framework offers a physically constrained basis for integrating pore–throat geometry, relaxation response, fluid occurrence, and seepage properties in the characterization of tight sandstone reservoirs. Full article

This study investigates an SAC-type injector nozzle used in a diesel high-pressure common-rail fuel-injection system. The mixture multiphase-flow model, RNG k-ε turbulence model, and Schnerr–Sauer cavitation model were employed to compare the internal flow characteristics of circular and elliptical nozzle orifices under different operating and geometric parameters. The results show that, as the inlet pressure increased from 110 to 170 MPa, the outlet velocity and mass flow rate of the elliptical orifice reached 495.80 m/s and 27.28 g/s, respectively, while the outlet vapor volume fraction increased to 0.161. As the outlet back pressure increased from 5 to 20 MPa, the outlet vapor volume fraction of the elliptical orifice was 41.32–46.49% lower than that of the circular orifice, whereas its mass flow rate was 4.84–23.54% higher. The geometric-parameter analysis indicated that superior internal flow performance was obtained at a nozzle-orifice angle of 75° and an inlet rounding radius of 0.03 mm. The converging elliptical orifice increased the outlet velocity and mass flow rate by 18.3% and 23.29%, respectively. These results demonstrate that the converging elliptical orifice can effectively mitigate flow separation and cavitation while improving outlet-flow uniformity and fuel-delivery performance. Full article

To address the supply–security pressures and hosting capacity assessment challenges arising from the high penetration of renewable energy into power systems, this paper proposes a comprehensive evaluation method for grid renewable energy hosting capacity based on the entropy weight method, technique for order preference by similarity to ideal solution, and grey relational analysis (EWM-GRA-TOPSIS). First, a multi-dimensional comprehensive evaluation index system is established, encompassing security and stability, operational economy, flexible power supply security, and renewable energy penetration. Subsequently, a comprehensive hosting capacity evaluation model is formulated. Within the operational simulation layer, key evaluation metrics across diverse renewable energy deployment alternatives are quantified based on time-series production simulation and power flow calculations. In the data processing layer, the EWM is employed to determine index weights, while GRA measures the morphological similarity between alternatives and the ideal sequence. Concurrently, TOPSIS evaluates their geometric proximity, enabling a coordinated trade-off among multi-dimensional metrics and the final ranking of the alternatives. Finally, the result output layer yields the comprehensive assessment outcomes and the prioritized ranking of the proposed scenarios. Simulation results demonstrate that the proposed method effectively evaluates the hosting capacity of various development scenarios, thereby providing a robust decision-making basis for power system planning and operation that balances high grid capacity with optimal comprehensive benefits. Full article

Artificial intelligence (AI) marketing systems increasingly plan campaigns, generate messages, assess performance, and revise outputs with limited human input. In such multi-agent systems (MAS), commercial optimization pressure may produce ethical compliance drift: gradual movement from acceptable persuasion toward detector-defined manipulation-risk signals. We examine this problem in a controlled OpenClaw simulation of a three-role AI marketing team. The study varies optimization pressure across baseline, moderate-pressure, and high-pressure operating regimes while holding the model backend, prompt pool, agent roles, and monitoring process constant. Optimization pressure significantly affected detector-defined manipulation-risk scores, and the observed pattern was non-monotonic. The moderate-pressure condition produced the highest observed mean, but moderate and high pressure were not statistically distinguishable in the pairwise comparison. These results reflect detector-based risk indicators in simulated marketing-agent outputs, not direct evidence of consumer harm, deception, or real-world behavioral manipulation. The findings support pressure-aware auditing as a standards-informed monitoring practice consistent with IEEE value-sensitive design principles, while also identifying the need for human annotation, hybrid detectors, and real-user validation before stronger governance claims are made. Full article

Urban flood resilience depends not only on the scale of infrastructure investment, but also on whether such investment can be translated into observable flood-mitigation outcomes. Focusing on the transformation from infrastructure response to flood outcomes, this study uses panel data for 21 prefecture-level cities in Guangdong Province from 2016 to 2022. Annual maximum monthly precipitation is used to represent rainfall pressure, stormwater pipe density to represent infrastructure scale, and the number of reported flood events to represent the outcome variable. A two-way fixed-effects Poisson pseudo-maximum likelihood (PPML) model is employed. The results show that, in the full sample, rainfall pressure is positively, but not significantly, associated with reported flood occurrence, while stormwater pipe density does not exhibit a stable negative moderating effect. The main conclusion remains broadly unchanged when alternative outcome and precipitation indicators are used, when pipe density is lagged by one period, and when a conservative sample is adopted. Extended analysis provides only limited weak negative evidence for Pearl River Delta cities, and this evidence is not robust across alternative specifications. The findings indicate that pipe length per unit of built-up area primarily reflects the scale of infrastructure provision and cannot be directly equated with the operational performance of the drainage system. By separating response inputs from outcome performance, this study reveals the conditional nature of the transformation from infrastructure scale to operational performance in urban flood resilience research and provides empirical support for a shift from infrastructure expansion toward performance-oriented and integrated governance in high-density coastal cities. Full article

With the accelerating global population aging process, home health care (HHC) has emerged as a promising service mode to satisfy surging elderly medical care needs and alleviate the pressure of offline medical institutions. As a core operational optimization problem in the HHC service system, the home health care routing and scheduling problem (HHCRSP) has attracted extensive research attention in recent years. Different from traditional HHCRSP research, this work proposes a bi-objective mixed-integer programming model for HHC, which integrates facility location, caregiver allocation, route planning and skill-matching rules. The model simultaneously minimizes two competing objectives: total operational cost and total penalty incurred from time window violations. To tackle the high-complexity NP-hard characteristics of this integrated optimization problem, an enhanced non-dominated sorting genetic algorithm (E-NSGA) is designed by introducing dedicated local search operators to improve solution quality. Comparative numerical experiments are carried out on 12 test instances extended from the classic Vidal benchmark, covering four patient scales of 70, 80, 90 and 100 patients. Four state-of-the-art multi-objective metaheuristics, i.e., MOEA/D, MOGWO, NSGA-II and NSGAII-MLS, are selected as baseline comparison algorithms. Experimental results reveal prominent performance advantages of E-NSGA over all comparison methods. In terms of the IGD metric, E-NSGA achieves IGD reductions of 20.19%, 86.30%, 24.98% and 37.72% against MOEA/D, MOGWO, NSGA-II and NSGAII-MLS, respectively. In terms of the Hypervolume metric, E-NSGA obtains performance improvements of 6.22%, 2019.42%, 10.36% and 18.04% relative to the four baseline algorithms. Such quantitative evidence verifies the strong comprehensive optimization capacity of the proposed E-NSGA for addressing the investigated problem. Full article

Climate change and rapid urbanization are reshaping the spatial relationship between flood risk and socioeconomic development, yet basin-scale evidence on where risk pressure and development capacity diverge remains limited. Taking 54 cities in China’s Pearl River Basin as the study area, this study adopts a dual-system evaluation framework integrating game-theory weighting, coupling coordination analysis, and spatial autocorrelation. Flood risk is characterized through hazard, exposure, vulnerability, and Resilience, while socioeconomic development is represented by economic scale, urban construction, and population agglomeration. This design extends previous Pearl River Delta-centered analyses to the entire basin and enables city-scale identification of risk–development imbalance. The results reveal a pronounced downstream–upstream gradient. The Pearl River Delta has the highest flood exposure (mean exposure index = 0.2603, 117% higher than the basin average of 0.1208), but strong Resilience and socioeconomic capacity prevent high exposure from translating into the highest overall risk. By contrast, east-central Guangxi emerges as a critical hotspot where moderate to high hazard overlaps with high vulnerability and weak Resilience. Coupling coordination remains generally low, shifting from basic coordination in parts of the Pearl River Delta to severe imbalance in upstream Guizhou, Guangxi, and Yunnan. The global Moran’s I is 0.4261 and significant at the 1% level, indicating marked spatial clustering, with high-high clusters concentrated in core Pearl River Delta cities and low–low clusters in eastern Yunnan and southwestern Guizhou. By distinguishing high exposure cities from high priority intervention areas, this study provides a potentially transferable framework for differentiated flood governance, infrastructure investment, and Resilience enhancement across large river basins. Full article

Anthropogenic pressure on aquatic environments is currently associated not only with the inflow of nutrients, but also with the presence of municipal micropollutants and complex mixtures of sewage origin. This study aimed to evaluate the growth response of Lemna minor (L. minor) and the behavior of the plant–medium system under conditions of a controlled chemical gradient reflecting an increasing degree of anthropogenic transformation of the aquatic environment. The experimental setup included four synthetic media: two variants of river water with varying anthropogenic loads and two variants of synthetic wastewater, one of which was enriched with caffeine as a marker of municipal pressure. The experiment was conducted in two independent 14-day series, analyzing changes in nitrate and orthophosphate concentrations, pH, conductivity, plant morphological condition, and final biomass. The most favorable growth conditions for L. minor were found in the river variants, especially in the medium with higher loading, whereas the wastewater variants caused growth inhibition, deterioration in plant condition, and greater instability of physicochemical parameters. In the wastewater media, nitrate concentrations did not show a consistent net decrease, while orthophosphate concentrations remained high. These observations indicate that the measured nutrient forms were not effectively reduced under the tested conditions. However, the processes responsible for their temporal patterns could not be identified from the monitored parameters. The addition of caffeine modified the system’s response, but its effect was not quantitatively consistent across both series. The results confirm the usefulness of synthetic media for modeling anthropogenic pressure gradients. Full article

Hydrophobic deep eutectic solvents (HDESs) have been recognized as effective environmentally friendly extraction media for the recovery of lipophilic bioactive chemicals. Nonetheless, their incorporation with sophisticated delivery systems remains mostly unexamined. This study aimed to develop a curcuminoid-rich powder formulation from turmeric (Curcuma longa L.) and to evaluate its physicochemical properties, antioxidant activity, and effects on cell metabolic activity in vitro. Initially, 30 HDES systems based on thymol or menthol were prepared and compared in terms of their curcuminoid extraction performance. The thymol/lactic acid system (2:1, molar ratio) produced the highest total curcuminoid concentration among the screened HDES systems. The extraction parameters were subsequently optimized using a Box–Behnken response surface design. Under the optimized conditions, the total curcuminoid concentration in the analyzed extract solution was 6692.12 ppm. Then, the obtained extracts were incorporated into a double-layer emulsification system by high-pressure homogenization and converted into encapsulated powder form by spray-drying. The particle distribution index (PDI) of the prepared emulsion system was determined as 0.282, indicating a homogeneous distribution of particles within the emulsion system. The total curcuminoid-based encapsulation efficiency of turmeric powders obtained using a double-layer encapsulation system was determined to be 87.33%. Under separately simulated gastric and intestinal conditions, the detected curcuminoid recovery values were similar, at 31.24% and 31.10%, respectively. The ABTS radical-scavenging activity measured after the simulated intestinal treatment reached 81.57%. However, the possible contribution of residual HDES components to this activity could not be determined. The encapsulated powder caused a concentration-dependent reduction in the metabolic activity of DU-145 prostate cancer and Caco-2 colorectal adenocarcinoma cells in the MTT assay. To conclude, the integrated approach enabled the production of a curcuminoid-rich powder with high encapsulation efficiency. The findings support further investigation of the formulation’s technological and biological properties. Full article

Stratospheric airship navigation requires accurate wind field measurements at a ~20 km altitude, where low pressure and density limit the effectiveness of conventional wind sensors. To address this, we present a compact direct-detection Rayleigh Doppler wind lidar based on the molecular double-edge technique. The system utilizes a 532 nm fiber-coupled pulsed laser (0.5 W, 5 ns) and a fixed-cavity dual-channel Fabry–Perot etalon as the frequency discriminator. A liquid crystal variable retarder (LCVR) combined with a polarization beam splitter (PBS) enables non-mechanical, high-speed beam switching between two orthogonal line-of-sight (LOS) directions for horizontal wind measurement. Systematic tests are performed in controlled wind fields within Mie-dominated and Rayleigh-dominated regimes. The lidar effectively captures the sharp radial velocity profiles at wind speeds up to 7.6 m/s. Comparative experiments with a reference anemometer show that the system delivers reliable performance at 0.48 m range resolution, with measurement uncertainty below 0.34 m/s. With its compact, lightweight, and high-precision design, the developed lidar demonstrates reliable wind measurement capability under laboratory conditions, indicating its potential for future deployment on stratospheric airships. Full article