Search Results (25,576)

The adjustable speed hydro-generating unit has a complex three-phase alternating current excitation structure. The existing rotor winding short circuit (RWSC) fault diagnosis methods are generally difficult to use to locate the fault location and identify the severity of the fault. Therefore, an offline diagnosis method for the internal RWSC of an adjustable speed hydro-generating unit is proposed in this paper. Firstly, after the unit is shut down, the low-voltage pulse signal is repeatedly injected into the rotor winding by the pulse generator. By comparing and analyzing the voltage response characteristics under different types of short circuit faults, an identification method of rotor winding short circuit fault type and fault phase based on detecting the reverse polarity sub-spike is proposed. Furthermore, the short circuit fault point can be accurately located by combining ensemble empirical mode decomposition (EEMD) with the Teager energy operator (TEO). Finally, the fault factor is constructed based on the area between the characteristic waveform and the zero line, and the quantitative evaluation of the severity of the short circuit fault is realized based on this. The effectiveness of the proposed fault diagnosis and location method is verified by the simulation results. Full article

Measuring the service levels and spatial equity of urban parks constitutes a core research topic within the field of environmental justice. Against the backdrop of low-carbon urban transformation and sustainable development, this study constructs an ecological supply indicator calculation model for parks based on landscape ecology theory. Leveraging spatio-temporal big data such as Points of Interest (POI) and second-hand property transactions, it establishes a demand evaluation indicator system centered on human activity intensity. The study employs the Gini coefficient and location entropy to gauge the spatial equity of park supply–demand balance, utilizing the Z-score method to classify supply–demand matching types. An empirical case study is conducted in Shenzhen. Findings indicate that despite Shenzhen possessing abundant global-scale park resources, a Gini coefficient of 0.489 reveals significant deficiencies in the equitable provision of park services, with spatial distribution exhibiting pronounced social stratification. Specifically: (1) location entropy values exhibit an east-high, west-low spatial pattern; (2) areas with high location entropy are predominantly concentrated in Dapeng New District, rich in green space resources, where supply exceeds demand, creating an imbalance; and (3) areas with low locational entropy values are predominantly distributed in industrial clusters such as western Bao’an and western Longgang, exhibiting contradictory characteristics of low supply and high demand. Overall, the distribution of park and green space resources exhibits a polarized pattern. Full article

Rapid changes in Arctic summer sea ice exert substantial influences on the polar climate system, maritime navigation, and resource exploitation, while subseasonal-to-seasonal (S2S) prediction of sea ice state remains highly uncertain. Using daily observations and reanalysis data of sea ice concentration (SIC) and thickness (SIT) from 1979 to 2023, together with concurrent atmospheric and oceanic fields, this study develops a multivariate linear Markov model to perform S2S predictions of Arctic summer sea ice. Sensitivity experiments with different variable combinations, weighting strategies, and modal truncation schemes are conducted, and predictive skill is systematically evaluated against persistence and climatological baselines. Results indicate that the model exhibits stable forecast skill without pronounced error accumulation at extended lead times. SIC predictability is primarily governed by its intrinsic spatiotemporal persistence and is significantly modulated by oceanic thermodynamic forcing, particularly sea surface temperature and surface net energy flux, highlighting a pronounced oceanic memory effect. In contrast, local atmospheric dynamic variables provide limited incremental skill. For SIT, predictability is dominated by its own historical state, with SIC contributing marginal short-term improvement and air–sea coupling exerting weak influence. Overall, the proposed framework effectively extracts dominant predictable signals with clear physical interpretability, providing a computationally efficient statistical approach for S2S prediction of Arctic summer sea ice. Full article

Caking and powder adhesion are widespread challenges in dry powder processes. The influence of process parameters such as humidity and temperature on the adhesion behavior of dry powders has been extensively studied in numerous studies. Besides that, the impact of other process characteristics, such as additional process parameters or wall materials, has received little attention so far. In addition, existing methods to characterize caking behavior do not account for powders in a fluidized state. To address phenomena based on process and material behavior, a test rig was specifically designed to investigate the adhesion of dry particles to different metal walls at varying speeds at a 90° angle, representing the main novelty of this study. The deposition area, deposition mass, and maximum deposition thickness were evaluated, and the correlations were discussed. The investigations revealed that at low velocities (<12 m/s) and for smooth surfaces (Sq < 0.3–0.4 µm), wall materials with a high ratio of dispersive to polar surface energy components (D/P: 13–15.8) exhibit minimal powder adhesion. The test rig has demonstrated its effectiveness as a straightforward method for measuring adhesion across various powder–wall material pairs and could serve as a valuable preliminary test for industrial applications. Full article

This study assesses regional science and technology (S&T) innovation efficiency across 30 Chinese provinces from 2011 to 2022, incorporating a sustainable development perspective. Employing a non-oriented global frontier super-slack-based measure (SBM) model that accounts for undesirable outputs, along with kernel density estimation, cluster analysis, and Moran’s I, the research investigates the spatiotemporal evolution of innovation dynamics. The findings demonstrate a marked upward trend, with the national average efficiency score rising from 0.260 to 0.703. Temporally, efficiency advanced through three stages: an initial period of universally low efficiency, a phase of widening disparities, and a final stage of overall improvement and stabilization. Spatial analysis reveals a persistent “strong in the east, weak in the west” disequilibrium; however, absolute β-convergence tests indicate a significant reduction in regional disparities (p < 0.05). Kernel density estimation reveals a shift from a polarized “pyramid” shape to a more balanced “spindle-shaped” distribution. This is evidenced by a decrease in kurtosis and a rightward shift in the median. Spatial autocorrelation, as measured by the Global Moran’s I, evolved from a statistically insignificant distribution in 2011 to a strong positive correlation (0.223, p < 0.05) by 2022. This progression reflects a transition from isolated “unipolar” hubs to integrated “multi-center block linkages.” The results suggest that, although polarization is diminishing and the national innovation baseline is improving, policy efforts should prioritize the development of emerging innovation corridors to address the remaining east–west divide. Full article

Desulfovibrio spp. are sulfate-reducing bacteria (SRB) associated with conditions such as inflammatory bowel disease (IBD) that are linked to intestinal barrier dysfunction (leaky gut). Previously, we reported that Desulfovibrio vulgaris (DSV) caused increased intestinal permeability by upregulating nuclear transcription factor Snail. However, the signaling mechanisms underlying this effect remain unclear. Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase that maintains intestinal barrier integrity and negatively regulates Snail and promotes its degradation by proteasomes. Rapamycin has been shown to protect the intestinal barrier and is also known to activate GSK-3. In this study, we investigated whether DSV disrupts intestinal barrier function through modulation of GSK-3 signaling and whether rapamycin could counteract these effects. Using a previously established DSV-induced paracellular permeability model using polarized Caco-2 monolayers, here, we showed that DSV induced inhibitory phosphorylation of GSK-3. Pretreatment of cells with rapamycin prevented DSV- induced phospho- inactivation of GSK-3, suppressed Snail expression and nuclear localization, and significantly reduced DSV-induced barrier permeability. Inhibition of proteasomal degradation with MG132 abolished the protective effects of rapamycin on barrier permeability, supporting a role for GSK-3–mediated proteasomal regulation of Snail. Together, these findings identify GSK-3 signaling as a novel mechanism underlying DSV-induced intestinal barrier dysfunction and highlight rapamycin as a potential therapeutic approach strategy to protect intestinal barrier integrity in response to DSV. Specifically, targeting the GSK-3/Snail pathway may represent a promising strategy to mitigate SRB-associated intestinal barrier disruption. Full article

This study develops a machine learning-based predictive model for identifying high-level clouds (HLCs). The model uses meteorological parameters as input features and is trained against human-recorded meteorological observations. A statistical analysis of the relationship between two independent methods of registering HLCs—lidar and meteorological observations—has been performed. Optimal thresholds for the total amount of cloud cover, at which meteorological data are consistent with lidar data, have been determined. The results demonstrate the promising performance of ML models in identifying the links between weather conditions and the probability of HLC detection, which is confirmed by ROC AUC (Area Under the Curve of the Receiver Operating Characteristic) values in the range of 0.87–0.88 for the presence and 0.77–0.78 for the absence of clouds, as well as balanced metrics Precision, Recall, and F1. The XGBoost (eXtreme Gradient Boosting) model proved to be the most robust, demonstrating the ability to effectively integrate data of various types for reliable prediction in various conditions. Full article

From falcons spotting prey to humans recognizing faces, the ability to rapidly process visual information depends on a foveated retinal organization that provides high-acuity central vision while preserving low-resolution peripheral vision. This organization is conserved along early visual pathways, yet remains under-explored in machine learning. Here, we examine the impact of embedding a foveated retinotopic transformation as a preprocessing layer on convolutional neural networks (CNNs) for image classification. By applying a log-polar mapping to off-the-shelf models and retraining them, we achieve comparable accuracy while improving robustness to scale and rotation. We demonstrate that this architecture is highly sensitive to shifts in the fixation point and that this sensitivity provides an effective proxy for defining saliency maps that facilitate object localization. Our results demonstrate that foveated retinotopy encodes prior geometric knowledge, providing a solution for visual searches and a meaningful classification robustness and localization trade-off. These findings provides a proof of concept in order to connect principles of biological vision with artificial networks, suggesting new, robust and efficient approaches for computer vision systems. Full article

Developing sensitive and reversible CO sensors requires precise control of material–analyte interactions. Using DFT, we investigate CO sensing on bimetallic (Fe, Pt) anchored on N-doped graphene (TM₂–N₄–C), focusing on active-site density effects. Three densities are considered: low (12.7 Å), medium (8.5 Å), and high (4.2 Å). FePt–N₄–C band gaps exhibit non-monotonic tuning, approaching metallicity at high density. CO chemisorbs on Fe sites, but physisorbs on Pt sites. FePt exhibits stronger synergistic adsorption than homonuclear counterparts. While adsorption generally strengthens with density, spin-polarized calculations qualitatively reorder this trend via spin delocalization. High temperatures drastically improve recovery; low-density FePt–N₄–C reaches 65 s at 498 K. Three design principles emerge: low-density heteronuclear systems for reversible sensing, medium-density high-spin states for ultra-sensitive capture, and high-density configurations for work function sensors. This work establishes active site density as a key electronic and kinetic knob for graphene-based CO sensors. Full article

Bioelectricity plays a vital role in regulating cellular behavior. During the process of tissue repair and regeneration, surface electrical signals provided by biomaterials are found to be helpful. The characteristics of these electrical signals typically vary depending on the specific tissue repair requirements. In this study, zinc oxide nanorod (ZNR) arrays were loaded onto a poly(vinylidene fluoride-trifluoroethylene) (PVTF) substrate via the hydrothermal method. The nanorods were subsequently tilted by uniaxial stretching to form a ZNR/PVTF composite film with in-plane, horizontally aligned ZNRs along the stretching direction on the surface. The distribution of ZNRs created a heterogeneous potential across the PVTF substrate. Under ultraviolet (UV) irradiation, the surface potential of the ZNRs increased by approximately 76 mV due to a photoelectric response, enabling the formation of an adjustable millivolt-level surface potential. After corona polarization, the dipoles within the PVTF were aligned to achieve piezoelectric properties. The existence of oriented surface ZNRs enhanced the piezoelectric response of the ZNR/PVTF film, allowing for volt-level dynamic electrical signals through a force-voltage coupling mechanism. The output voltage increased from 1.32 V (PVTF) to 2.42 V (ZNR/PVTF) under the same 30° bending condition. Moreover, the ZNR/PVTF film exhibited excellent short-term biocompatibility toward bone marrow stem cells (BMSCs). Overall, this work presents an effective strategy for generating multiscale electrical signals through external field applications, demonstrating strong potential for tissue repair and regeneration. Full article

The rise in emerging viral outbreaks has intensified the need for novel antiviral therapies and highlighted the untapped potential of natural products. Influenza viruses, particularly avian strains, continue to evolve rapidly, yet the antiviral properties of Jordan’s native plants remain largely unexplored. This study focused on avian influenza and screened twelve endemic plant species, using ethanol to selectively extract polar phytochemicals likely to interact with the hydrophilic active site of neuraminidase (NA). Among these, Arbutus andrachne leaf and fruit extracts emerged as potent in vitro inhibitors of recombinant N9 neuraminidase, a key enzyme in influenza replication, with IC₅₀ values of 31.6 µg/mL and 32.9 µg/mL, respectively. LC-MS analysis identified hyperoside as the major shared flavonoid in both extracts, which may contribute to the observed inhibitory activity. These findings support the potential of A. andrachne as a natural source for herbal preparations with antiviral activity. Full article

This study examines a low-processed, food-grade extraction concept for peppermint leaves (Mentha × piperita L.) using solvents consistent with the principles of green chemistry and an infusion-like protocol. Primary extraction (2–30 min; 50–100 °C) was carried out using water, plasma-treated nanowater, a glycerol–water mixture (65%), an ethanol–water mixture (50%; at room temperature and at 50 °C), and rapeseed oil. To evaluate the potential use of biomass within a circular economy model, the residue remaining after the first extraction was subjected to secondary extraction under identical time–temperature conditions. Primary and secondary extracts were characterized in terms of total phenolic content (TPC), total flavonoid content (TFC), essential oil (EO) recovery, and antioxidant activity (DPPH and FRAP), and extraction yields were expressed relative to a 70% methanolic reference (TPC/TFC) and to the initial EO content in the plant material. Under the most favorable conditions (10 min; 100 °C; ethanol–water at 50 °C), the highest extraction yields of polar phytochemicals (TPC and TFC) were obtained with water and nanowater, whereas the ethanol–water mixture (50%) and rapeseed oil provided the greatest recovery of essential oil (up to complete depletion after the second extraction). Antioxidant activity showed a similar dependence on solvent type, with water and nanowater extracts exhibiting the highest DPPH/FRAP values. Importantly, secondary extraction contributed a substantial share of the total recovered bioactive compounds (often >30% of combined TPC/TFC), confirming that post-extraction residues remain a valuable raw material. The results support a practical, sequential strategy for designing peppermint extracts: aqueous and glycerol systems for phenolic-rich extracts, and ethanol and oil systems for essential-oil-enriched preparations, with secondary extraction enabling simple, low-energy biomass valorization. Full article

Background: Arterial hypertension in childhood is an increasing health concern, often associated with structural and functional cardiovascular or renal alterations. This study aimed to investigate the prevalence and type of non-stenotic renal artery anatomical variants in children with systemic hypertension and to assess their possible association with cardiac involvement. Methods: A total of 107 children and adolescents with hypertension (mean age 15.4 ± 2.7 years) were evaluated. Hypertension was defined as blood pressure persistently above the 95th percentile for over one year, confirmed by 24 h ambulatory blood pressure monitoring. Patients with known secondary causes were excluded. All underwent renal vascular imaging by CT or MRI and echocardiographic assessment of left ventricular morphology and function. Results: Renal artery anatomical variants were found in 69 of 107 patients (65%), mainly unilateral or bilateral accessory polar arteries. Other anomalies found (left renal vein narrowing or duplication, severe left renal artery stenosis) were excluded from the statistical analysis. Normal renal vasculature was observed in only 32%. Left ventricular hypertrophy was detected in 41%, highlighting a significant prevalence of target-organ involvement. No statistically significant differences were found in terms of hypertension or hypertrophy between patients with renal artery anatomical variants and those without. However, patients with renal anomalies more frequently required dual antihypertensive therapy (p = 0.025). Conclusions: Renal artery anatomical variants, even in the absence of overt stenosis, may contribute to the pathogenesis of pediatric hypertension and complicate its management. Systematic evaluation of renal vasculature should be considered in the diagnostic workup to improve risk stratification and guide management strategies. Full article

Atherosclerosis is a complex, multifactorial disease that progresses through distinct stages: initiation, progression, and complication, ultimately leading to acute coronary syndromes (ACS). Endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages are central players in this process, influencing plaque stability and vulnerability. Insulin-Like Growth Factor 1 (IGF-1), soluble-Klotho (S-Klotho), and the Growth Hormone Receptor exon 3 deletion polymorphism (GHRd3) have emerged as key modulators of vascular health, impacting these cellular components through various mechanisms. IGF-1 supports endothelial function, enhances VSMC survival and migration, and mitigates inflammation by inhibiting macrophage recruitment and activation, ultimately reducing the risk of plaque destabilization. S-Klotho, an anti-aging protein with potent anti-inflammatory and antioxidant properties, has been linked to vascular protection, with its deficiency associated with endothelial dysfunction, vascular calcification, and impaired VSMC survival. Evidence suggests that IGF-1 may enhance Klotho shedding, indicating a potential synergistic role in maintaining vascular integrity. This narrative review aims to outline the fundamental stages of atherosclerosis progression, consolidate current evidence on the roles of IGF-1 and S-Klotho in modulating key cellular components of atherosclerosis, and shed light on their potential involvement in plaque healing—an area that remains largely unexplored. By integrating established molecular mechanisms, we explore how these factors may contribute to endothelial integrity, VSMC survival, and macrophage activation and polarization, potentially shaping a more stable plaque phenotype and influencing future therapeutic strategies in cardiovascular disease. Full article

Gut ischemia/reperfusion (I/R) injury releases damage-associated molecular patterns (DAMPs), such as extracellular cold-inducible RNA-binding protein (eCIRP). Milk fat globule–epidermal growth factor VIII-derived oligopeptide 3 (MOP3) is a novel peptide enabling macrophage uptake of eCIRP via αvβ3-integrin. MOP3 reduces inflammation in gut I/R, but its mechanisms are not completely understood. We hypothesized MOP3 promotes macrophage polarization toward an anti-inflammatory, M2-like phenotype in gut I/R. We induced gut I/R in mice through 60 min of superior mesenteric artery occlusion followed by 4 h of reperfusion. Intestines were evaluated for macrophage polarization by flow cytometry and immunofluorescence histology. Peritoneal cavity macrophages were isolated from mice and treated with eCIRP, MOP3, α_vβ₃-antibody, and/or naïve IgG for 4 or 24 h. Polarity was assessed by flow cytometry, qPCR, and ELISA. Compared to the sham, the M2 proportion after gut I/R decreased by 22.7%, and the M1 proportion increased by 241%. MOP3 treatment increased the M2 proportion by 64.3%, and the M1 proportion decreased by 22.7%. In eCIRP-stimulated macrophages, MOP3 treatment increased M2-like and reduced M1-like cell-surface markers, gene expression, and cytokine levels. α_vβ₃ antibody dramatically reduced MOP3′s effects. MOP3 promotes M2 polarization through α_vβ₃ integrin-mediated clearance of eCIRP, a novel mechanism whereby MOP3 reduces gut I/R injury. Full article