Search Results (36,110)

Territorial space serves as a common platform for both ecosystem carbon sink functions and socioeconomic functions. Rapid urbanization has intensified the competition between carbon source and carbon sink areas, making the measurement of carbon sink conflicts critical for carbon emission reduction and land use optimization. This study takes Hangzhou as its research area and uses districts and counties as the basic evaluation units. Drawing on three dimensions—spatial carbon emission pressure, spatial carbon sequestration capacity, and spatial instability—the study develops a model to assess the intensity of territorial carbon sink conflicts. It systematically evaluates the conflict intensity across Hangzhou’s 13 districts and counties in 2020 and analyzes land use change from 2010 to 2020. The results indicate that (1) from 2010 to 2020, Hangzhou’s built-up areas expanded to some extent, leading to intensified spatial conflicts between carbon sources and carbon sinks; and (2) in 2020, light and general conflict areas were mainly distributed in outlying counties (e.g., Lin’an, Chun’an); moderate conflict areas were in the urban periphery (e.g., Fuyang, Binjiang); and intense to severe conflict areas were in central urban districts (e.g., Shangcheng, Gongshu, Xiaoshan). Overall, carbon sink conflicts exhibited a concentric pattern of “uncontrolled core—periphery on the verge—distant suburbs under control.” This study provides a scientific basis for mitigating future carbon sink conflicts in Hangzhou and offers a perspective for identifying and managing such conflicts in other rapidly urbanizing regions. Full article

Oxygen vacancies are a key factor determining the efficiency of the CO₂ hydrogenation reaction and play a crucial role in CO₂ adsorption and activation. However, effectively regulating the concentration of oxygen vacancies to enhance the performance of the light-driven reverse water gas shift (RWGS) reaction remains a challenge. To address this, this study successfully developed Pt/TiO₂ catalysts with varying oxygen vacancy concentrations by controlling the morphology of TiO₂. Structural characterization results indicate that, compared to Pt/TiO₂-NR, Pt/TiO₂-NB exhibits a higher oxygen vacancy (O_V) concentration and greater CO₂ absorption. Catalytic performance evaluation results showed that under an irradiance of 2.5 W/cm², the CO production rates of the Pt/TiO₂-NB catalyst reached 57.03 mol·g_Pt⁻¹·h⁻¹. Furthermore, the catalyst maintained excellent catalytic stability during 45 h of continuous operation, demonstrating good potential for practical applications. Full article

Background and Objectives: Hypoxia-inducible factor-1 alpha (HIF-1α) is a central regulator of cellular responses to hypoxia and has been implicated in the pathophysiology of several neurological disorders. Parkinson’s disease (PD) and restless legs syndrome (RLS) have both been associated with alterations in oxygen sensing, mitochondrial dysfunction, and disturbances in amino acid metabolism; however, the relationship between HIF-1α and amino acid metabolic pathways in these disorders remains incompletely understood. The present study investigated circulating HIF-1α concentrations and amino acid metabolite profiles in patients with PD and RLS. Materials and Methods: In this cross-sectional study, 55 participants were enrolled, including 30 healthy controls, 12 patients with PD, and 13 patients with RLS. Plasma HIF-1α concentrations were measured using an enzyme-linked immunosorbent assay, and amino acid metabolites were quantified by liquid chromatography–tandem mass spectrometry. Group comparisons were performed using non-parametric methods with FDR correction. Age- and sex-adjusted regression analyses, correlation analyses, and PCA were used to assess metabolic relationships and group discrimination. Results: Significant group differences were observed for HIF-1α and multiple amino acid metabolites. Compared with controls, both PD and RLS patients exhibited significantly higher concentrations of arginine, citrulline, homocitrulline, and HIF-1α, whereas ornithine concentrations were significantly lower. Arginine demonstrated the largest effect size among all biomarkers (ε² = 0.713). HIF-1α concentrations showed a progressive increase across groups, with the highest levels observed in RLS. Correlation analyses revealed strong positive associations of HIF-1α with arginine, citrulline, and homocitrulline, and an inverse association with ornithine. These findings remained significant after adjustment for age and sex. PCA showed clear separation between controls and disease groups. Conclusions: PD and RLS are characterized by a shared metabolic signature involving elevated HIF-1α, increased arginine-pathway metabolites, and reduced ornithine concentrations. The detected associations between HIF-1α and metabolites of the arginine–citrulline–ornithine pathway suggest a potential link between hypoxia-related signaling and metabolic dysregulation in both disorders. These findings support further investigation of HIF-1α-associated metabolic pathways as potential biomarkers and therapeutic targets in neurodegenerative and movement disorders. Full article

PM₁₀ filters provide short-term quantitative information on particle-bound potentially toxic elements (PTEs), whereas mosses integrate deposition and accumulation over longer periods but do not provide air-volume-normalised concentrations. Their combined use may therefore provide a more complete assessment of atmospheric PTE deposition. The study aimed to assess whether active moss biomonitoring and filter-based PM₁₀ monitoring provide complementary information on atmospheric deposition of PTEs under comparable exposure conditions. During the six-month campaign in Opole, PM₁₀ was collected during repeated 24 h sampling events, while three moss species: Pleurozium schreberi, Sphagnum fallax, and Dicranum polysetum were exposed cumulatively. PTE concentrations were determined by ICP-MS; particle-size descriptors, including Q₁₀, Q₅₀, and Q₉₀, were analysed for a subset of filters, whereas net concentration change and RAF were calculated relative to identically processed unexposed moss controls. Spearman correlation, PCA, and Bray–Curtis dissimilarity were used for data analysis. The material retained on the PM₁₀ filters was dominated by Fe, Zn, and Pb, whilst elevated peak values for Cd, Zn, and Pb indicated episodic enrichment in some samples. In mosses, Pb and Co showed the most consistent relative enrichment, while mean RAF exceeded 1.0 for five elements in P. schreberi and two elements each in D. polysetum and S. fallax. PCA separated PM₁₀ from moss profiles, with the first two components explaining 80.4% of the variance, while PM₁₀-moss Bray–Curtis distances ranged from 0.75 to 0.81. The results indicate that PM₁₀ filters and mosses record different but complementary aspects of the atmospheric PTE signal. The simultaneous use of both methods allows the atmospheric PTE signal to be interpreted at two levels: the short-term composition of PM₁₀ material retained on the filters, and the long-term retention and accumulation of elements within the moss matrix. Full article

Evidence from clinical trials indicates that dietary protein plays an important and often underappreciated role in lipoprotein lipid metabolism. For this narrative review, literature searches were conducted in the PubMed and Cochrane Central Register of Controlled Trials databases for articles describing randomized controlled trials (RCTs) and systematic reviews and meta-analyses of RCTs, as well as dietary guidelines and dyslipidemia management recommendations, using search terms for protein quantity, source (e.g., animal- and plant-based), and type (e.g., dairy, meat, soy, and nuts) and effects on lipids and lipoproteins in humans. Findings indicated that dietary intakes of both animal-based and plant-based proteins, when replacing refined carbohydrates or saturated fatty acids, lower circulating concentrations of atherogenic lipoproteins. Protein from plant sources appears to produce a somewhat larger effect on lipoprotein lipid concentrations than protein from animal sources. Individual amino acids (e.g., branched-chain amino acids), protein food fractions (e.g., whey), and food-derived peptides may independently impact lipoprotein lipid metabolism. Beyond the effect of replacing one macronutrient for another, the biochemical pathways responsible for the effects of dietary protein on lipoprotein lipid metabolism in humans have not been fully defined. The importance of dietary protein in a healthy diet is emphasized in recent dietary recommendations for the general population and for individuals with dyslipidemias. Additional research is warranted to determine the amount of dietary protein and the best balance of food source(s) to optimize its benefits on lipoprotein lipid concentrations, as well as the mechanisms for these effects. Full article

Methane partial oxidation (POM) offers a promising pathway for syngas production, but achieving optimal catalyst performance requires precise control of promoter loading. We systematically investigated cerium (Ce) promotion on nickel-based catalysts supported on aluminum oxide (Ni/Al₂O₃) catalysts across 1–3 wt.% loadings and identified a critical discovery: catalyst performance exhibits a pronounced non-monotonic response to Ce concentration. The 1 wt.% Ce-promoted catalyst (Ni+1Ce/Al) achieved the superior performance with 65% methane conversion and 60% hydrogen yield at 650 °C, maintaining stable output over 275 min time-on-stream. This smaller Ce amount tunes NiO reducibility, oxygen mobility, and metal–support interactions, resulting in improved activity performance of Ni+1Ce/Al. Notably, Ce promotion shifts the H₂/CO ratio from 2.5 to 2.9, with the increased hydrogen yield arising from enhanced water–gas shift chemistry and indirect oxidation pathways. Excess cerium (2–3 wt.%) causes performance deterioration, Ni particle agglomeration, and thus loss of Ni active sites, demonstrating that Ce operates as a structural promoter with a well-defined appropriate concentration window. Moreover, the best performing catalyst (Ni+1Ce/Al) remained stable during 20-h long-term POM. An artificial neural network model achieved exceptional predictive accuracy (R = 0.9758 overall), validating the experimental findings. These results indicate that the best Ce loading for industrial application is 1 wt.% and the traditional alumina supports can be competitive in performance with the advantage of thermal stability and cost-effectiveness when doped with rare-earth elements. Full article

Pleurotus pulmonarius (Fr.) Quél. is a commercially important edible mushroom recognized for its nutritional and nutraceutical value. However, the influence of alternative agricultural waste substrates on its biochemical composition remains insufficiently characterized. This study investigated the effect of four cultivation substrates, coconut waste (PpC), paddy husk (PpP100), paddy husk supplemented with sawdust (PpP20) and rubberwood sawdust as control (PpS), on the macro- and microelement profile, secondary metabolite composition, and antioxidant activity of P. pulmonarius fruiting bodies. Analytical methods included ICP-MS and FAAS for elemental analysis; GC-MS for fatty acid, carbohydrate and phenolic profiling; Kjeldahl method for total protein; FTIR spectroscopy for structural characterization; and four complementary antioxidant assays (DPPH, ABTS, CUPRAC, FRAP). Coconut waste substrate promoted the highest protein accumulation and elevated concentrations of iron, zinc, and specific phenolic acids (vanillic, protocatechuic). Paddy husk-based substrates favored carbohydrate accumulation, particularly trehalose, while sawdust supported the greatest lipid content, dominated by linoleic acid. Potassium was the predominant macroelement across all variants. Antioxidant activity was highest in PpP100 and PpC across all four assays. FTIR confirmed a mushroom-specific polysaccharide, protein, and lipid profile in all samples. The results demonstrate that agricultural waste represents sustainable, value-added alternatives to conventional sawdust, capable of maintaining or enhancing the nutritional and nutraceutical quality of oyster mushrooms to enhance agricultural production. Full article

Programmable electromagnetic environments, including reconfigurable intelligent surface (RIS)-assisted systems, are often described in terms of physical or controllable degrees of freedom. Such counts, however, do not determine which channel or operator directions can actually be distinguished by a finite measurement architecture. This paper develops an operator-space formulation of observable degrees of freedom for programmable propagation systems. We distinguish three nested layers: the physical operator space generated by the family of physically admissible propagation operators, the effective operator space selected by architectural constraints, and the observable subspace induced by a finite probing architecture. Once the effective space is fixed, observability is characterized by the spectrum of the associated measurement Gram operator. To remove arbitrary amplitude scaling, we introduce a common probe-energy normalization and define the resolution-dependent observable dimension $N_{\mathrm{obs}}\left(\eta \right)$ from the normalized Gram spectrum. The same spectrum also yields an observability condition number, which quantifies the stability of the visible subspace. We then extend the construction to symmetry-resolved operator spaces, showing how invariant probing can create sectorial blind subspaces and how controlled symmetry breaking produces second-order restricted visibility inside the original blind subspace. The mathematical ingredients are standard finite-dimensional tools from operator theory, frame theory, representation theory, and matrix concentration; the contribution is their integration into a measurement-oriented degrees-of-freedom framework for programmable electromagnetic environments. Numerical experiments with normalized probing families, sectorial decompositions, controlled symmetry breaking, and a canonical narrowband RIS-inspired model illustrate that architectures with the same effective dimension and probing budget can exhibit substantially different observable dimensions and conditioning. The results support the view that practical electromagnetic design should optimize not only the number of accessible modes or control states, but also the Gram geometry through which those directions are measured. Full article

This study presents a computational analysis of degradation caused by cavitation and hydro-abrasive erosion in a low-head axial microturbine ($H=4\mathrm{m}$), incorporating strategic air injection as a passive mitigation technique. Using Computational Fluid Dynamics (CFD) within ANSYS CFX 2025 R2, the study investigates hydrodynamic performance and the spatial distribution of surface wear across the runner blades. The turbine geometry was developed from aerofoil profiles mapped onto cylindrical coordinates, using a structured three-dimensional mesh with localized refinement to ensure grid independence. Physical modeling employed the Shear Stress Transport (SST) turbulence model, with cavitation dynamics governed by the Rayleigh–Plesset equation and sediment transport modeled using a Lagrangian framework incorporating the Finnie erosion model. The numerical framework showed good agreement with reference characteristic curves, confirming its predictive accuracy. The results indicate that vapor cavities form predominantly on the suction side, whereas solid particle erosion highly concentrated on the pressure side of the blades, where the outer $20\%$ of the span accounts for over $91\%$ of the total erosion intensity. Parametric assessments of controlled air injection revealed a highly non-linear mitigation response, identifying IAVF 2 as the optimal air-injection case. This configuration reduced integrated erosion by $0.95\%$ and maximum localized erosion by $6.17\%$. In contrast, excessive air volumes accelerated material removal due to localized flow distortion. The findings indicate that carefully controlled air injection is a viable strategy for extending the operational lifespan of small-scale hydropower assets. Full article

To investigate the hydrogen leakage dispersion and explosion characteristics of fuel cell vehicles in an underground parking garage, experimental and numerical simulation studies were conducted. The results show that the hydrogen leakage concentration exhibits an evolutionary pattern of a rising stage followed by a plateau stage, with a stratified distribution characterized by higher concentration at the top and lower concentration at the bottom. Higher leakage flow rate leads to a faster concentration growth rate, while the two are not in a direct proportional relationship. The hydrogen concentration near the leakage outlet was relatively low. The maximum explosion overpressure reached 194 kPa at a hydrogen concentration of 20%, with higher overpressure observed on the walls. Flame propagation followed a four-stage law, and a Laval nozzle effect appeared at the leakage outlet. Ventilation can rapidly suppress hydrogen accumulation, and the ventilation effect approached optimality at a wind speed of 8 m/s. The explosion venting area exerted the most significant influence: when the venting area increased from 0.36 m² to 1.44 m², the overpressure decreased by 76%. The explosion venting position was the second most influential factor, while the vent shape had negligible effects. This study provides a scientific basis for the safety prevention and control of hydrogen energy applications in underground spaces. Full article

The dynamics of methane (CH₄), nitrous oxide (N₂O) and carbon dioxide (CO₂) in groundwater have rarely been investigated. As dissolved gases they may be transported to distant sites and, hence, to the atmosphere. Crumps Cave (CC) is located on a perched aquifer in south-central Kentucky. Water was sampled at a waterfall within the cave located 15 m below the surface, at two adjacent surface wells 15 m and 50 m deep, providing samples from the epikarst and regional aquifer, respectively. Dissolved gases and geochemistry parameters were analyzed for seasonal changes across three years of weekly monitoring (2015–2017) using Kruskal–Wallis H tests and Bonferroni-corrected pairwise comparisons. Dissolved CO₂ concentrations are mainly controlled by percolation through the epikarst, influenced by soil respiration, and vary with rainfall and seasonal temperature fluctuations. CH₄ showed a site-dependent pattern: concentrations were significantly elevated in warm seasons at the shallow and deep wells, where anaerobic conditions and agriculturally derived organic matter promote methanogenesis; no seasonal variation was detected at the cave site, where oxic conditions limit CH₄ year-round. N₂O was significantly elevated in cold seasons at all three sites, driven by cold-season denitrification of agriculturally derived nitrates. N₂O did not differ between sites, indicating seasonal temperature-driven denitrification as the primary control rather than site hydrology, with cold-season denitrification of agriculturally derived nitrates from fertilizer application. Indirect gas emissions are characteristic of karst systems and may be transported or stored in aquifers through complex interactions of groundwater recharge, microbial activity, and seasonal land-use variability. Full article

Three-dimensional numerical investigations into the synergistic mechanism of composite pile retaining systems consisting of large-diameter bored cast-in-place piles and small-diameter micro-grouted steel pipe piles remain limited. To address this gap, a refined three-dimensional finite element model was established using ABAQUS based on the Hutan Park Station excavation project of Dalian Metro Line 5. Five design cases were analyzed by varying pile diameter, pile spacing, and the presence or absence of micro piles. The main findings are as follows: (1) The maximum horizontal soil displacement in all cases remained below 8 mm, indicating satisfactory excavation stability. (2) The inclusion of micro piles promoted stress redistribution within the inter-pile soil and was associated with a more pronounced soil arching tendency, as indicated by the displacement contour patterns. (3) Based on the comparison between Case 3 and Case 5, where the spacing between bored cast-in-place piles increased from 2.0 m to 3.0 m while maintaining the composite support configuration, the maximum horizontal displacement and maximum bending moment decreased by approximately 12% and 9%, respectively. The inserted micro-grouted steel pipe piles participated in lateral load transfer, enhanced stress redistribution, and reduced local stress concentrations acting on the primary bored piles. Under the investigated geological and support conditions, the numerical results suggest that the introduction of micro steel pipe piles may improve deformation control and load-sharing performance in composite pile-supported excavations. The proposed support configuration shows potential for reducing the number of large-diameter bored piles while maintaining acceptable excavation performance and overall support stability. Full article

Platform-mediated short-term rental (STR) markets concentrate intensely in heritage urban cores, yet the temporal stability of this concentration remains poorly understood. This study examines spatial dynamics of STR concentration in Dubrovnik’s UNESCO-listed historic core across five biennial cross-sections (2017–2025) using complete administrative eVisitor registration data and an H3 hexagonal grid at resolution 11. Global and local spatial autocorrelation (Moran’s I, LISA, Getis-Ord Gi*), Emerging Hot Spot Analysis for spatiotemporal typologies, and bivariate LISA to distinguish capacity saturation from fragmentation were applied. Results demonstrate structural persistence: Moran’s I remained highly significant (p < 0.001) across all periods including COVID-19 disruption (range 0.417–0.467, CV = 4.4%), despite 53% supply growth and only 3.7% spatial expansion. Consecutive hotspots dominated typological classification, indicating active consolidation. Capacity analysis revealed concordant High–High patterns (56.8% of significant cells) with zero High–Low associations, confirming saturation not fragmentation. Findings support spatial lock-in in STR markets: concentration persists because locational advantages are properties of place rather than market volume, requiring spatially differentiated regulation rather than aggregate supply controls. Full article

The spreading and film formation of organic polymer solutions on liquid surfaces are key processes in coating, printing, and interfacial processing. However, the mechanisms by which aqueous polymers regulate spreading kinetics and film morphology are not yet fully understood. In this study, the free spreading of Poly(3-hexylthiophene-2,5-diyl) (P3HT)/chlorobenzene solution on poly(vinyl alcohol) (PVA) aqueous surface was employed as a model system to investigate how PVA concentration, molecular weight, degree of hydrolysis, and temperature collectively govern spreading behavior and film formation. Video recording was used to monitor the evolution of the spreading and front-edge morphology, while step-profilometry, UV–visible absorption spectroscopy, and atomic force microscopy were employed to characterize the resulting films in terms of thickness distribution, optical uniformity, and surface roughness. The results reveal that PVA can significantly regulate both the spreading kinetics of P3HT/chlorobenzene droplets and the final film morphology. PVA concentration exhibited a non-monotonic effect on spreading behavior, with intermediate concentrations favoring larger spreading areas and more continuous films. Increasing the PVA molecular weight altered the concentration-dependent spreading window and enhanced asymmetry at the spreading front, whereas reducing the degree of hydrolysis decreased interfacial tension and thereby increased the thermodynamic driving force for spreading, yet the actual spreading rate remained constrained by molecular diffusion, interfacial adsorption, and chain-segment rearrangement. Temperature and a saturated chlorobenzene vapor atmosphere further modulated the interplay among solvent evaporation, interfacial driving force, and viscous dissipation. Under optimized conditions, the resulting P3HT films displayed uniform thickness profiles, consistent optical absorption, and nanoscale surface roughness, and could be repeatedly transferred, assembled into well-defined multilayer structures, and printed onto flexible and curved substrates. These findings demonstrate that PVA aqueous subphase provides a tunable low-shear route for transferable P3HT thin-film fabrication and suggests its potential applicability to other polymer film-forming systems. Full article

The preparation of platelet-rich plasma (PRP) requires precise density-based centrifugation of anticoagulated whole blood to achieve an optimal hematologic bioformulation while enhancing platelet recovery efficiency. Commercial PRP systems exhibit substantial heterogeneity in processing architecture, with variable platelet yields and inconsistent cellular composition profiles. In this clinical PRP device evaluation, 70 sequential samples sourced from two independent clinical facilities were used to evaluate the performance characteristics of the XCELL 60 mL single-spin centrifugation platform. Two different PRP preparations were consistently prepared as per physician preferences: PRP-1 and PRP-2. The main differences between these two preparations were the concentration of leukocytes and reduction in red blood cells. The system was evaluated based on critical PRP performance metrics. The results demonstrated the following: (1) A consistent 8-fold increase in platelet concentration relative to baseline whole blood was achieved. (2) The average platelet capture rate (PCR) was 83%. (3) The total available platelets (TAPs) in the PRP specimen produced from both groups combined were 10.8 ± 2595 billion platelets within a final product volume of 6 mL. (4) Hematocrit values were reduced to <2–6% across sites (reduction of 94% and 84% in RBCs, respectively). Finally, (5) a customizable leukocyte content (20.9–25.4 × 10⁹/L) was achieved without comprising platelet yield. This single-spin centrifugation architecture achieved performance parity with historically preferred double-spin systems while reducing the processing time and number of preparation steps. Engineering analysis established that high-precision platelet recovery and bioformulation control are achievable through optimized single-spin centrifugal design, enabling standardized therapeutic dosing for autologous regenerative medicine applications. Full article