Search Results (21,217)

Cobalt disulfide (CoS₂) features highly active catalytic sites and is regarded as a promising candidate for electrocatalytic hydrogen evolution. In this study, molybdenum-doped cobalt disulfide (CoS₂:Mo) was synthesized via a facile hydrothermal approach. XRD analysis confirms that the obtained samples crystallize in a cubic pyrite structure, with diffraction peaks consistently shifting towards lower angles. SEM characterization reveals that the samples exhibit microrod-like morphologies with an average size of approximately 1 μm. Integrated analyses from XRD, XPS, and EDS mapping demonstrate that Mo is uniformly distributed across the surface and successfully doped into the CoS₂ lattice. Electrochemical measurements indicate that the CoS₂:Mo sample delivers a low overpotential of 122 mV and a Tafel slope of 128 mV dec⁻¹ at a current density of 10 mA cm⁻² in alkaline media, significantly surpassing the performance of pure CoS₂ and MoS₂. Moreover, the CoS₂:Mo exhibits an enhanced double-layer capacitance, with a C_dl value of 2.72 mF cm⁻², superior to that of pure CoS₂ (1.63 mF cm⁻²) and MoS₂ (0.31 mF cm⁻²). Mo doping enhances conductivity and active sites, thereby boosting electrocatalysis. This work presents an effective strategy for the development of cost-efficient and high-performance non-precious metal electrocatalysts. Full article

Research based on the similarities between canine and human mammary tumors should extend beyond clinical, pathophysiological, epidemiological, and histopathological characteristics to include applicable molecular markers with prognostic significance. However, despite shared similarities, important differences must also be considered in comparative and translational studies. The nuclear erythroid 2-related factor (NRF2), a nuclear transcription factor that regulates the expression of antioxidant proteins, is pathologically activated during carcinogenesis. The role of NRF2 in human breast cancer is well established, making it a potential prognostic marker. Objectives: This study aimed to evaluate NRF2 tissue expression in mammary neoplasms of female dogs and its association with tumor progression, other prognostic factors, and survival. Methods: A group of 57 female dogs was studied. Tissue samples of mammary glands from 10 healthy dogs and 47 dogs with mammary neoplasms (39 malignant tumors and 8 benign tumors) were examined for NRF2 immunoexpression. Clinicopathological data and immunohistochemical expression, assessed by histochemical score (H-score), were correlated. Results: NRF2 tissue expression showed a predominantly cytoplasmic distribution and a lower H-score in tumors with higher malignancy grading. Dogs with higher NRF2 H-scores had improved survival rates (p = 0.0036). Univariate analysis revealed significant associations between H-scores < 135 and behavior (p = 0.007), tumor size (p = 0.001), and Ki-67 index (p = 0.018). Conclusions: These results suggest that NRF2 also holds prognostic value in the evaluation of canine mammary tumors. Full article

In this article, we introduce and investigate a novel class of graphs that are called Power Congruence Graph PCGs, which are defined over the vertex set V$=\{0,1,2,\dots ,n-1\}$ where two vertices $a,b\in V$ are adjacent if $a^k\equiv b^k(modm)$ for some modulus $m\in M_p$, where $M_p=\{p,p^2,\dots ,p^t\mid p^t<n\}$. We thoroughly characterize the structural features of these graphs, establishing that each PCG decomposes into a union of $d+1$ complete components, where $d={\displaystyle \frac{p-1}{gcd(k,p-1)}}$. The component sizes are explicitly given for n, p, and k. This decomposition highlights symmetry patterns in the component arrangement, emphasizing connectedness and structural balance. We derive key graph-theoretic metrics such as degree distribution, size, chromatic number, clique number and domination number. We also compute the adjacency and Laplacian matrices, as well as their spectra and associated graph energies to better understand the structural similarities and differences among PCGs with different exponents and prime moduli. This paper offers a systematic framework for comprehending power congruence based graph constructs, integrating number theory with structural and spectral graph theory and illustrating the natural symmetry that underpins these combinatorial structures. Full article

This study investigates the flow behavior of gyroid scaffolds using computational fluid dynamics (CFD) and three rheological models, Newtonian, Power-law, and Carreau, to assess the influence of pore size, inlet velocity, and scaffold size on wall shear stress (WSS) and permeability. The results show that non-Newtonian models yield substantially higher and broader WSS distributions than the Newtonian model, reflecting the importance of shear-dependent viscosity for physiologically realistic simulations. Larger pore size reduces the WSS and increases the permeability. Nevertheless, localized high-shear regions persist, particularly for the non-Newtonian fluids. Higher inlet velocities produce an increase in both WSS and permeability. However, this effect is lees remarkable for the Newtonian model. Comparisons between small and large scaffolds show lower wall shear stress levels in the larger geometry due to reduced local velocity gradients and a more evenly distributed flow field. Overall, rheological models influence the magnitude and heterogeneity of WSS. These findings highlight the need to incorporate non-Newtonian models when evaluating the scaffold performance in tissue engineering applications. Full article

The Qilian Mountains serve as a crucial ecological security barrier in western China, and the soil structural stability of alpine meadows directly affects regional ecological security and the sustainable utilization of grasslands. However, current research on grazing mostly relies on short-term artificially controlled experiments, which differ greatly from the pattern of long-term natural grazing. Herein, this study abandoned the artificially controlled grazing method and selected sampling areas with stable grazing regimes for more than a decade. Taking no grazing (CK) as the control, four treatments were established, including light grazing (LG), moderate grazing (MG), heavy grazing (HG) and extreme grazing (EG). The particle size distribution and stability of mechanically stable and water-stable soil aggregates in different soil layers were determined. Combined with environmental and biological factors, the effects of grazing on the structure and stability of soil aggregates were elucidated. The results showed that no grazing improved the mechanical stability of soil aggregates but reduced their water stability. Light and moderate grazing maintained a balanced and resistant soil structure, with the surface soil being more fragile than the subsurface soil. Heavy and extreme grazing led to severe structural degradation, with the subsurface soil being more fragile than the surface soil. Soil aggregate stability was jointly regulated by elevation, soil properties, root biomass, nitrogen forms, mineralization and microbial biomass. In conclusion, from the perspective of soil structural stability and sustainable utilization, light and moderate grazing represent the optimal utilization mode for the alpine meadows of the Qilian Mountains. This mode not only maintains the structural stability of subsurface soil aggregates but also balances biological cementation and physical disturbance, thus avoiding the insufficient water stability under no grazing and the risk of structural fragmentation under heavy or extreme grazing. Environmental and biological factors mediated the divergent responses of mechanical and water stability to different grazing intensities. The findings of this study provide a scientific basis and new insights for the rational grazing management and soil conservation of alpine meadows in the Qilian Mountains. Full article

Seasonal permafrost areas undergo long-term freeze–thaw cycles, severely compromising the strength of foundation soils. Consequently, deformation and settlement under long-term cyclic traffic loads are greater than in normal temperature areas, leading to potential safety hazards. This study focuses on soft clay soils in seasonal permafrost areas. Remoulded soft clay is subjected to freeze–thaw cycles, followed by a series of long-term cyclic traffic load tests using the GDS dynamic triaxial testing system and pore size analyses using the nuclear magnetic resonance (NMR) technology. The study aims to investigate the effects of varying freeze–thaw cycles, compaction coefficients, and types of curing agents on the cumulative plastic strain of soft clay. The findings indicate that under identical freeze–thaw conditions, both the presence of curing agents and the increase of the soil’s compaction coefficient significantly restrain the deformation of freeze–thawed soils. In the micro perspective, freeze–thaw cycles cause irreversible fracturing of the soil’s internal framework, while the addition of curing agents effectively mitigates the pore enlargement effect. The resulting pore size distribution differs by about 4% from the original distribution, which is consistent with the patterns observed in dynamic triaxial tests. Full article

Mercury (Hg) bioaccumulation in freshwater fish represents a major pathway of human exposure, particularly in cascade reservoir systems where hydrological retention and legacy contamination can enhance methylmercury (MeHg) formation and trophic transfer. This study quantified total mercury (THg) concentrations in seven tissues of seven fish species from the Arda River cascade (Bulgaria). Multi-tissue measurements were integrated with morphometric predictors, multivariate statistical analyses, and combined deterministic and probabilistic human-health risk assessments. Muscle and liver contained the highest THg concentrations, whereas gills and gonads exhibited the lowest levels. Predatory species and larger individuals accumulated significantly more Hg, reflecting trophic magnification and size-dependent exposure. A longitudinal gradient across the cascade reservoirs suggests hydrological retention effects influencing mercury distribution. Species- and tissue-specific size–Hg relationships further indicate heterogeneous bioaccumulation dynamics among taxa. Risk assessment indicated acceptable exposure for adults and pregnant women at average consumption (140 g·week⁻¹), but elevated exposure for children consuming high-Hg predators. Monte Carlo simulations (N = 30,000) revealed upper-tail risks, while Safe Weekly Intake thresholds provided species-specific consumption limits. These findings highlight the value of integrating multi-tissue monitoring with probabilistic risk modelling to support evidence-based fish-consumption advisories in contaminated freshwater systems. Full article

With the continuous renewal of urban greening, pollen released by allergenic tree species has become a prominent environmental issue affecting residents’ health. However, existing research still lacks city-wide, rapidly replicable methods for identifying allergenic tree species and assessing exposure risks. Taking Beijing’s central urban districts as a case study, this research establishes a method for the automated identification of allergenic tree species and the assessment of pollen exposure risks based on high-resolution satellite imagery. This study coupled tree species distribution results derived from model inference with population density per unit area to delineate three tiers of exposure risk zones. Subsequently, these risk zones were overlaid with the road network within the study area to determine the distribution of roads with low, medium, and high exposure risk. Public transport stop locations were then introduced as a proxy variable for areas of high population mobility. Lorenz curves and Gini coefficients were calculated to quantify the spatial equity of pollen exposure risk. The results indicate that the model reliably identifies target tree species, with approximately 117,000 valid targets. Exposure risks exhibit significant clustering characteristics and can form continuous expansions along road networks. Incorporating population factors shows minimal change in risk concentration, suggesting pollen exposure risk is primarily driven by the spatial clustering of allergenic tree species and their accessibility within road networks. This risk is highly correlated with the spatial distribution patterns and accessibility characteristics of allergenic tree species, rather than being solely determined by population size. This study provides foundational data and methodological support for urban tree species identification, pollen exposure risk management, and optimised greening configurations. Full article

Background/Objectives: Accurate determination of active pharmaceutical ingredient (API) particle size within dry powder inhaler (DPI) formulations is essential for ensuring effective pulmonary delivery but remains analytically challenging due to low API content and micronized particle size. Methods: In this study, scanning electron microscopy (SEM) coupled with energy-dispersive X-ray microanalysis (EDX) was used to directly identify and calculate the API particle size within several different commercial DPI products fit for purpose under regulatory constraints. The method exploits unique elemental markers inherent to each API, enabling reliable discrimination from excipients without prior sample modification or API extraction. Results: Large-area SEM–EDX mapping was used to localize API particles, followed by high-magnification imaging and confirmatory spot microanalysis. Particle sizes were manually measured for at least 50 API particles per formulation using image analysis software, and particle size distribution parameters were calculated from equivalent spherical diameters. Conclusions: The methodology was successfully applied to Spiriva^®, Anoro^® Ellipta, and Relvar^® Ellipta inhalation powders, revealing micronized APIs with distinct morphological features and verifying systematic application across products. Cross-validation against laser diffraction measurements of pure APIs demonstrated statistical equivalence, confirming the robustness and analytical utility of the proposed method for particle size assessment in DPI formulations. Full article

To address the low efficiency of tetracycline (TC) ozonation caused by low ozone solubility, short aqueous half-life, and mass-transfer limitations, an ozone micro-nano bubble (O₃-MNBs) oxidation system was designed and systematically compared with conventional ozone sparging (Conv-O₃). Thus, this study assessed the bubble size distribution, zeta potential, ozone dissolution and decay behaviors in water, ·OH concentration, and TC oxidation products, elucidating the degradation pathways and underlying mechanisms enabled by O₃-MNBs. Relative to Conv-O₃, O₃-MNBs increased the steady-state dissolved ozone concentration by 2.57–4.33 times, reduced the ozone decay rate constant by 41.3%, and enhanced ·OH generation by 2.3 times. TC degradation in the O₃-MNB system exhibited a distinct two-stage kinetic behavior, following second-order kinetics in the initial period (0–30 s) and first-order kinetics thereafter (30–120 s). Accordingly, the TC removal efficiency of O₃-MNBs reached 96.25% within 120 s, which was 81.25% higher than that of Conv-O₃. Notably, TC removal under Conv-O₃ obeyed first-order kinetics throughout, with an apparent rate constant only 7.14% of that obtained with O₃-MNBs. These improvements were attributed to the sustained and efficient supply of oxidants, high dissolved ozone and ·OH radicals, promoting the conversion of TC intermediates toward low m/z small-molecule end products, with greater ring opening and skeletal fragmentation. Our findings suggest that the enhanced biodegradability results in a markedly reduced burden and environmental risk for subsequent biological or advanced treatment processes. Therefore, this study highlights the potential of O₃-MNBs to enhance ozone utilization and oxidation intensity, providing mechanistic insights and technical support for rapid pretreatment of antibiotic-containing wastewater. Full article

In this study, we investigated the long-term evolutionary dynamics of human norovirus GII.17[P17] using the RNA-dependent RNA polymerase (RdRp) region and the VP1 capsid gene, integrating phylogenetics, time-scaled inference, phylodynamics, and structure-based analyses. Maximum-likelihood phylogenies of both genomic regions consistently resolved four major clades (Clades 1–4). VP1 patristic-distance distributions indicated higher within-clade diversity in the phylogenetically basal Clades 1 and 3, whereas Clades 2 and 4 showed lower diversity, consistent with recent demographic expansion. Similarity-plot analysis identified pronounced variability in the VP1 P2 domain, while the S and P1 domains remained comparatively conserved, supporting P2 as the primary hotspot of diversification. Bayesian time-scaled analyses estimated the most recent common ancestor around 1993 (VP1) and 2000 (RdRp) and revealed two major lineages (Clade 1/2 and Clade 3/4), with the split between Clades 3 and 4 occurring around 2016–2017. Bayesian skyline plots showed a marked increase in effective population size after 2013, and substitution-rate estimates indicated faster evolution in VP1 than in RdRp, with higher VP1 rates in the Clade 3/4 lineage than in Clade 1/2. Capsid dimer modeling further mapped high-confidence conformational B-cell epitopes and positively selected residues predominantly to the distal surface of P2, with broadly conserved spatial patterns across clades. Compared with the Clade 1 reference (Kawasaki323), Clade 2 accumulated numerous P2 substitutions, whereas Clades 3 and 4 retained fewer changes and remained closer to Clade 1 at the amino-acid level. Together, these results suggest lineage turnover within GII.17[P17] driven by constrained diversification at the P2 surface, potentially contributing to the recent predominance of the Clade 3/4 lineage. Full article

To enhance the early-age properties of steel slag cement mortar and promote the resource utilization of metallurgical solid waste, in this study, nano-SiO₂ (KH-NS) was modified using a KH550 silane coupling agent. The hydration kinetics and microstructure evolution were systematically analyzed by means of a macroscopic performance test (setting time and compressive strength) and multi-scale microscopic characterization (characterized by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, Thermogravimetry-Differential Thermal Analysis, and isothermal calorimetry). The influence mechanism of its content on the early performance of the steel slag cement system was systematically studied. Research findings indicate that at a given dosage, increasing the proportion of KH-NS results in a shorter setting time for steel slag mortar. When the KH-NS dosage reaches 1.5%, the initial and final setting times of steel slag mortar decrease by 24.21% and 21.20%, respectively. The addition of KH-NS effectively enhances the compressive strength of mortar, with a particularly pronounced effect on early strength prior to 14 h of curing. At a KH-NS dosage of 1.5%, the onset of the accelerated phase of hydration heat release in steel slag cement mortar is advanced by 2.5 h. Mechanistic studies indicate that KH-NS accelerates cement hydration by promoting C₃S dissolution and C-S-H gel nucleation through interactions between surface silanol groups (Si-OH) and amino groups (-NH₂). Furthermore, KH-NS refines the pore structure via a micro-aggregate filling effect, reducing the number of harmful pores and improving the pore size distribution. KH-NS continuously consumes Ca(OH)₂ through pozzolanic reactions to generate C-S-H, with its reactivity increasing with higher dosage. Research confirms that KH-NS significantly enhances the early strength and density of steel slag mortar, providing both theoretical justification and technical support for developing low-carbon building materials based on solid waste with high dosage. Full article

This paper presents a theoretical framework for predicting molten jet breakup at the outlet of a rotating granulation system operating without forced excitation. The study focuses on the critical regime in which mechanical excitation is absent, and jet disintegration is governed solely by intrinsic hydrodynamic instabilities. The analysis is based on the linear stability theory of viscous liquid jets, employing the Rayleigh–Plateau and Tomotika approaches adapted to melt conditions typical of industrial granulation processes. The Navier–Stokes equations are formulated in a cylindrical coordinate system for an axisymmetric, incompressible viscous jet with appropriate kinematic and dynamic boundary conditions at the free surface. The breakup mechanism is characterized using key dimensionless parameters, including the Ohnesorge, Weber, Reynolds, and Capillary numbers, enabling identification of the dominant instability regime. Analytical expressions are derived for the most unstable wavelength, perturbation growth rate, breakup time, and characteristic droplet diameter. These relationships are evaluated for representative thermophysical properties of molten urea. Theoretical predictions obtained from classical Rayleigh theory, viscosity-corrected models, and modern empirical correlations show strong agreement, with deviations not exceeding 7%. Sensitivity analysis indicates limited dependence of the predicted droplet diameter on moderate variations in viscosity, surface tension, and jet velocity. The proposed model provides a physically grounded basis for predicting and controlling granule size distribution in rotating granulation systems operating without external mechanical excitation. Full article

The large volumes of fine flotation tailings constitute a persistent challenge for the conventional treatment of minerals due to their wide particle size distribution and their low metal contents. In this work, the potential of passive inertial microfluidics for the selective redistribution of mineral particles from actual copper flotation tailings is studied. A suspension of tailings was treated in a rectangular microfluidic channel in a laminar regime, without an external magnetic field or sheath flux. The solid fractions obtained were characterized in terms of particle size distribution, phase composition and element content. The microfluidic treatment induced a systematic distribution of the particles between the output fractions. The central fraction was enriched with coarser particles, the median particle size increasing from about 15 µm in the feed to about 20 µm, and had high concentrations of Cu, Fe, Ag and Zn, with enrichment factors reaching 2.0 to 2.7 depending on the element. On the other hand, the lateral fraction was mainly composed of finer particles (D50 ≈ 13 µm) and depleted in metalliferous phases. The elemental mass balance confirmed that the observed enrichment results from selective redistribution rather than from a loss of material. These results indicate that the separation of the particles cannot be explained solely by size effects and are consistent with a preferential migration of the denser and metal-rich particles towards stable inertial focusing trajectories. Full article

This study explores the feasibility of using municipal solid waste incineration bottom ashes (MSWIBAs) as a partial replacement for cement in concrete with respect to the fresh and hardened properties of concrete. MSWIBA samples from five Swedish incineration plants (BA1–BA5) were collected and analyzed for their mineral composition and particle size distribution (PSD). The samples (BA3 and BA5), exhibiting better pozzolanic behavior and particle sizes closer to those of conventional cement, were selected for further detailed study. Mechanical activation was performed on the BA3 and BA5 samples. Concrete mixes were prepared with 10% and 20% (by mass) cement replacements utilizing raw and activated BA3 and BA5 samples. The resulting concrete specimens were evaluated through slump, density, and compressive strength tests at 7, 28, and 56 days. The results showed that activated MSWIBAs improved the workability of the concrete specimens compared with the control concrete mix, and the density of the concrete decreased with increasing the MSWIBA content. The compressive strength of the concrete mixes generally decreased as the replacement level of MSWIBAs increased. At 56 days, the concrete mix with 10% raw BA5 reached about 77% of the compressive strength of the control concrete mix, whereas mixes with 20% raw or activated MSWIBAs reached about 58%. The concrete mix with BA3 performed better than the mix with BA5 at 7 days, while the concrete mix with BA5 showed higher later-age compressive strength. In addition, mechanical activation of MSWIBAs did not significantly improve compressive strength of concrete mixes. Despite the reduction in compressive strength when using MSWIBAs, this sustainable concrete contributes to the development of climate-friendly concrete and offers potential environmental benefits. Full article