Search Results (3,816)

This study addresses a critical challenge in global conservation: understanding how rare species contribute to ecosystem structure and resilience. The ecological role of the endangered black-and-white snub-nosed monkey in China’s temperate mountain forests was examined, with the hypothesis that its tree-shaking behavior alters forest structure and microclimates to enhance ecosystem health. To assess long-term impacts, current monkey-inhabited forests were compared with historical sites abandoned over decades, by analyzing tree gaps, forest structure, and environmental conditions. Monkeys’ canopy-disturbing actions were also directly observed. Findings revealed monkey activity created more canopy gaps (38.3% in current habitats vs. 29.9~33.5% in abandoned sites) and altered microclimate conditions, which boosted plant diversity and optimized the community’s vertical and age structures. Current forests supported nearly twice as many tree species, 2.5 times as many shrub species, and threefold more herb species than areas abandoned for 40 years. Even 20 years after monkeys disappeared, abandoned sites retained higher diversity and gaps, showing lasting ecological benefits. These results confirm the monkey’s vital role as a resilience promoter, demonstrating how rare species can shape healthier ecosystems. This highlights the need to prioritize protecting such species, as their survival not only preserves biodiversity but also sustains ecosystem functions crucial for human well-being. Full article

The human placenta is a complex organ that supports fetal development and is rich in extracellular matrix proteins and growth factors, making it suitable as a biomaterial in wound care. Placenta-derived amnion-only allografts have traditionally been used in the clinic, but they lack the structural and biochemical complexity of the full three-layer placental membrane, which includes the amnion, intermediate, and chorion layers. Advances in tissue engineering have enabled preservation of multiple layers, giving rise to multilayer placental-based Cellular and Acellular Matrix-like Products (CAMPs) such as Full-Thickness (FT; amnion, intermediate, chorion) and ACA (amnion, intermediate, chorion, amnion). Although these advanced CAMPs are increasingly applied clinically, their molecular composition has not been comprehensively defined. This study presents a global proteomic analysis of FT and ACA, complemented by targeted multiplex analysis of soluble proteins and an in vitro angiogenesis assay. Proteomic profiling identified 8908 structural and bioactive components, with 32.5% of proteins associated with tissue repair and remodeling pathways. Multiplex analysis confirmed accessibility of biologically relevant soluble factors. Endothelial tube formation assays further supported biological relevance, demonstrating that soluble proteins in FT and ACA support angiogenesis. These data provide a molecular characterization of multilayer CAMPs and underscore their potential to deliver durable wound coverage while supporting the local microenvironment. Full article

The impact of counterion structure, especially variations in constitutional and stereochemical isomers, on the properties and performance of AABSs remains under-explored. This study investigates how structural variations, particularly the stereochemistry of diammonium cyclohexane (DACH) counterions, influence the self-assembly behavior of AABSs. Four AABSs: undecanoyl-glycine, -L-alanine, -L-valine, and -L-leucine, were paired with six DACH counterions representing cis/trans isomers of 1,2-, 1,3-, and 1,4-DACH. Critical micelle concentrations (CMCs) were determined via conductimetry, and micellar sizes were measured using dynamic light scattering. The degree of counterion binding (β) was calculated to probe micelle stability, while geometry-optimized structures of the DACH isomers were obtained using density functional theory. Lastly, pH measurements were taken to probe the protonation of DACH counterions at their natural pH, where both the DACH counterion and AABS headgroups intrinsically behave as buffers. Results indicate that while surfactant hydrophobicity primarily dictates CMC in other AABS/DACH combinations, trans-1,3-DACH leads to consistently higher CMCs. This deviation likely arises from its structural conformation, which positions the amine groups an intermediate distance of ~4.4–4.5 Å apart, allowing a small fraction of divalently charged counterions to form strong electrostatic bridging pockets at the micelle interface. These interactions dominate over headgroup effects, leading to elevated and surfactant-independent CMC values. Regarding size and other unusual trends in the systems, cis- isomers formed slightly larger micelles, and trans-1,4-DACH induces abnormal aggregation in undecanoyl-glycine leading to temperature dependent gel formation. These findings highlight the significant influence of counterion structure on AABS behavior and support counterion design as a strategy for enhancing surfactant performance in sustainable applications. Full article

The topic of the present study is the aerodynamic performance of a Natural Laminar Flow (NLF) wing for UAVs at low speed. The basis is a thoroughly tested NLF airfoil in the wind tunnel of NASA which is well-customized for light aircrafts. The aim of this work is the numerical verification that a typical wing design (tapered with moderate aspect ratio and wash-out), being constructed out of aerodynamically highly efficient NLF airfoils during cruise, can deliver high aerodynamic loading under minimal freestream turbulence as well as realistic atmospheric conditions of intermediate turbulence. Thus, high mission flexibility is achieved, e.g., short take off/landing capabilities on the deck of ship where moderate air turbulence is prevalent. Special attention is paid to the effect of the Wing Tip Vortex (WTV) under minimal inflow turbulence regimes. The flight conditions are take off or landing at moderate Reynolds number, i.e., one to two millions. The numerical simulation is based on an open source CFD code and parallel processing on a High Performance Computing (HPC) platform. The aim is the identification of both mean flow and turbulent structures around the wing and subsequently the formation of the wing tip vortex. Due to the purely three-dimensional character of the flow, the turbulence is resolved with advanced modeling, i.e., the Improved Delayed Detached Eddy Simulation (IDDES) which is well-customized to switch modes between Delayed Detached Eddy Simulation (DDES) and Wall-Modeled Large Eddy Simulation (WMLES), thus increasing the accuracy in the shear layer regions, the tip vortex and the wake, while at the same time keeping the computational cost at reasonable levels. IDDES also has the capability to resolve the transition of the boundary layer from laminar to turbulent, at least with engineering accuracy; thus, it serves as a high-fidelity turbulence model in this work. The study comprises an initial benchmarking of the code against wind tunnel measurements of the airfoil and verifies the adequacy of mesh density that is used for the simulation around the wing. Subsequently, the wing is positioned at near-stall conditions so that the aerodynamic loading, the kinematics of the flow and the turbulence regime in the wing vicinity, the wake and far downstream can be estimated. In terms of the kinematics of the WTV, a thorough examination is attempted which comprises its inception, i.e., the detachment of the boundary layer on the cut-off wing tip, the roll-up of the shear layer to form the wake and the motion of the wake downstream. Moreover, the effect of inflow turbulence of moderate intensity is investigated that verifies the bibliography with regard to the performance degradation of static airfoils in a turbulent atmospheric regime. Full article

Seismic facies recognition constitutes a fundamental task in seismic data interpretation, playing an essential role in characterizing subsurface geological structures, sedimentary environments, and hydrocarbon reservoir distributions. Conventional approaches primarily depend on expert interpretation, which often introduces substantial subjectivity and operational inefficiency. Although deep learning-based methods have been introduced, most rely solely on unimodal data—namely, seismic images—and encounter challenges such as limited annotated samples and inadequate generalization capability. To overcome these limitations, this study proposes a multimodal seismic facies recognition framework named GAT-UKAN, which integrates a U-shaped Kolmogorov–Arnold Network (U-KAN) with a Graph Attention Network (GAT). This model is designed to accept dual-modality inputs. By fusing visual features with knowledge embeddings at intermediate network layers, the model achieves knowledge-guided feature refinement. This approach effectively mitigates issues related to limited samples and poor generalization inherent in single-modality frameworks. Experiments were conducted on the F3 block dataset from the North Sea. A knowledge graph comprising 47 entities and 12 relation types was constructed to incorporate expert knowledge. The results indicate that GAT-UKAN achieved a Pixel Accuracy of 89.7% and a Mean Intersection over Union of 70.6%, surpassing the performance of both U-Net and U-KAN. Furthermore, the model was transferred to the Parihaka field in New Zealand via transfer learning. After fine-tuning, the predictions exhibited strong alignment with seismic profiles, demonstrating the model’s robustness under complex geological conditions. Although the proposed model demonstrates excellent performance in accuracy and robustness, it has so far been validated only on 2D seismic profiles. Its capability to characterize continuous 3D geological features therefore remains limited. Full article

Fermenting seaweed with koji fungi transforms its chemical composition, generating bioactive compounds absent in the raw material. We previously reported that the fungal fermentation of the edible red alga Pyropia yezoensis (Nori) produces betaine structural analogs (such as betaine, stachydrine, and carnitine), which are of particular interest because of their physiological roles and potential health benefits. Using metabolomic profiling, we compared non-fermented Nori with powders fermented by three industrially important fungi: Aspergillus luchuensis mut. kawachii (white koji fungus), Aspergillus oryzae (yellow koji fungus), and Monascus purpureus (red koji fungus). All fermentations enhanced the levels of betaine and carnitine, but stachydrine production was unique to the yellow koji fungus. Precursor patterns revealed distinct metabolic strategies: the yellow koji fungus exhibited an intermediate detectable choline oxidation route and strong proline methylation, the white koji fungus rapidly converted choline without intermediate accumulation, and the red koji fungus favored carnitine and proline but produced little stachydrine. Fermentation also shifted the methylation balance toward a state that supports methyl-dependent pathways. These findings reveal clear species-specific strategies for the production of betaine structural analogs, providing a mechanistic basis for understanding the metabolic divergence among koji fungi and guiding the targeted design of functional seaweed products. Full article

Accurate modeling and simulation of lower limb rehabilitation exoskeleton (LLRE) enables effective control resulting in enhanced performance and ensuring efficient rehabilitation. There are two primary objectives of this study. First is to validate the existing models and second is to identify the optimal modeling approach for exoskeletons. For validation, firstly a lower limb rehabilitation exoskeleton is modeled using three different modeling approaches which include analytical modeling, bond graph modeling, and modeling through Simscape (SS). Thereafter, dynamic responses of analytical and graphical modeling are compared with SS model using key dynamic response parameters, including rise time, peak time, and others. The SS-based physical model can be employed for validation because SS, unlike mathematical modeling, uses unit-consistent physical domain data and, therefore, serves as an intermediate step between mathematical modeling and hardware validation. Secondly, to identify the most suitable modeling approach, a structured and comprehensive comparison of different modeling approaches based on aspects such as control domain, complexity, ease of use, and other relevant factors is carried out. The results highlight the qualitative strengths and limitations of the three approaches. Previous studies focus on individual methods and lack such comparison. This work contributes to the validation of models and identification of an efficient and effective modeling methodology for LLRE. The findings reveal that Simscape™ is the most suitable approach for modeling LLREs as it provides multidisciplinary system modeling and supports real-time simulation. The validated model can now be employed for advancements in model-based control design. Moreover, the identified optimal approach provides an insight to researchers and engineers for model selection in early-stage design and control development of complex mechatronic systems. Future work includes comparison of dynamic responses with actual hardware responses to experimentally validate the effectiveness of the model for real-world patient assistance and mobility restoration. Full article

Oxidative stress induces reactive oxygen species (ROS) accumulation, which compromises sperm DNA integrity, cellular homeostasis, and semen quality in Hainan black goats. This study aimed to mitigate ROS-mediated sperm damage by examining the protective effects of curcumin on metabolic regulation and sperm structural integrity. Semen samples were treated in vitro with varying concentrations of curcumin (5, 25, 50 μmol/L) under oxidative stress conditions. The intermediate concentration (25 μmol/L) was most effective at enhancing sperm quality. Following treatment, sperm motility, membrane integrity, and acrosome stability were significantly improved (p < 0.05), while ROS levels and apoptosis rates decreased. Antioxidant enzyme activities—glutathione peroxidase (GPX, p < 0.05), catalase (CAT, p < 0.05), and superoxide dismutase (SOD, p < 0.05)—were markedly elevated. Metabolomic analysis identified 48 differential metabolites (p < 0.05), including gluconic acid, 3-hydroxybutyric acid, and argininosuccinic acid, which were mainly involved in antioxidant defense, energy metabolism (e.g., the citrate cycle), and osmoregulatory pathways. Lipidomics revealed reduced lipid peroxidation and increased polyunsaturated fatty acid content, correlating with enhanced membrane stability. Transmission and scanning electron microscopy revealed preservation of sperm ultrastructure, with reduced mitochondrial and chromatin damage. Quantitative PCR further indicated curcumin-mediated downregulation of pro-apoptotic genes (BAX, Caspase3, and FAS) and upregulation of the anti-apoptotic gene BCL2 (p < 0.05). These findings demonstrate that Curcumin at 25 μM mitigated menadione-induced oxidative stress in goat sperm in vitro, improving antioxidant status, mitochondrial function and membrane integrity while reducing apoptosis. Multi-omic profiling supported redox and lipid homeostasis restoration. These findings establish proof-of-principle in an acute oxidative model. Full article

Furfural and 5-hydroxymethylfurfural are considered as essential platform molecules for the chemical industry, acting as precursors and intermediates of numerous products. They are produced from pentoses and hexoses, respectively, in an acid medium. In this work, biomass from a green macroalgae, Ulva rigida, was treated under acidic conditions provided by heterogeneous catalysts in order to promote the dehydration of its monosaccharides into furfural and 5-hydroxymethylfurfural. Particularly, two functionalized mesoporous silicas, HMS and SBA-supported metal oxides (Nb₂O₅ and ZrO₂), were used as catalysts. Their textural, structural, and acid properties were deeply studied, providing excellent BET surface areas (ranging 424 to 1204 m²/g) and a high concentration of acid sites (220–460 µmol/g), which then translated into great catalytic performances (77.8% and 64.1% of furfural and HMF molar yields, respectively, using HMS-Nb) after a 4 h of reaction time at 180 and 160 °C, respectively. The catalyst showed excellent stability and recyclability as it could be reused for up to five reaction runs with only a slight decrease in performance. Full article

With the rapid advance of digital technologies, the service industry has become a key driver of sustainable economic growth and the restructuring of international trade. Drawing on value-added trade flows for five pivotal service industries—construction, air transportation, postal telecommunications, financial intermediation, and education—over 2013–2021, this study examines the spatial evolution of the global service value chain (GSVC). Using social network analysis combined with a Temporal Exponential Random Graph Model (TERGM), we assess the dynamics of the GSVC’ core–periphery structure and identify heterogeneous determinants shaping their spatial networks. The findings are as follows: (1) Exports across the five industries display an “East rising, West declining” pattern, with markedly heterogeneous magnitudes of change. (2) The construction industry is Europe-centered; air transportation exhibits a U.S.–China bipolar structure; postal telecommunications show the most pronounced “East rising, West declining” shift, forming four poles (United States, United Kingdom, Germany, China); financial intermediation contracts to a five-pole core (China, United States, United Kingdom, Switzerland, Germany); and education becomes increasingly multipolar. (3) The GSVC core–periphery system undergoes substantial reconfiguration, with some peripheral economies moving toward the core; the core expands in air transportation, while postal telecommunications exhibit strong regionalization. (4) Digital technology, foreign direct investment, and manufacturing structure promote network evolution, whereas income similarity may dampen it; the effects of economic freedom and labor-force size on spatial network restructuring differ significantly by industry. These results underscore the complex interplay of structural, institutional, and geographic drivers in reshaping GSVC networks and carry implications for fostering sustainable services trade, enhancing interregional connectivity, narrowing global development gaps, and advancing an inclusive digital transformation. Full article

Chitosan films obtained by solution casting were investigated by broadband dielectric spectroscopy (BDS) to explore both their glass transition and the effects of thermal annealing on molecular dynamics, deriving from residual water content as well as from cold crystallization. Glass transition at low temperatures could be evidenced in as-produced as well as thermally annealed films, where non-Arrhenian dielectric relaxation processes, consistent with a structural (α) relaxation, could be detected. The process detected at low temperatures could reflect the dynamics of residual water slaved by the polymer matrix. Secondary (β) relaxations, along with a slow process ascribed to interfacial polarization at the amorphous/crystalline interfaces, were concurrently detected. In most cases, a further Arrhenian process at intermediate temperatures (α_c) was present, also indicative of crystallization. Notably, the α processes, due to the primary relaxation of the polymer matrix plasticized by water, could be discriminated from other processes, present in the same frequency range, thanks to improvements in the dielectric fitting strategy. All relaxation processes showed the expected dependence on T_a. The more accurate exploration of the glass transition for chitosan helps to better rationalize its crystallization behavior, in view of an optimized application of this biopolymer. Full article

Soil bacterial communities are vital for ecosystem functioning in the humid tropics, yet their response to land-use change remains poorly understood. This knowledge gap is exacerbated by the lack of long-term studies. We employed a space-for-time substitution approach to assess the effects of land-use intensification on soil bacterial communities across a gradient of anthropogenic disturbance in Trinidad. Three sub-watersheds (Arouca = pristine, Maracas = intermediate, Tacarigua = intensive) were selected, each containing adjacent forest, grassland, and agricultural land uses. We combined geophysical soil apparent electrical conductivity (ECa-directed) sampling with 16S rDNA gene amplicon sequencing to characterize bacterial communities and their relationships with soil and landscape properties. Soil properties were the primary determinant of bacterial community structure, explaining 56% of the variation (p < 0.001), with pH, clay content, hygroscopic water, and nutrient availability as key drivers. Bacterial α-diversity differed significantly among sub-watersheds (p < 0.01), with Tacarigua exhibiting lower richness and diversity compared to Arouca and Maracas, but not across land uses. While a core microbiome of ten bacterial families was ubiquitous across land uses, indicating a stable foundational community, land-use intensification significantly altered β-diversity (p < 0.01 among sub-watersheds). Agricultural soils showed the greatest divergence from forest soils (p < 0.05), with a marked decline in key Proteobacterial families (e.g., Xanthomonadaceae, Pseudomonadaceae) involved in nutrient cycling and plant growth promotion. Although inherent soil properties shape the core microbiome, land-use intensification acts as a strong secondary filter, shifting soil bacterial communities toward more stress-resistant Firmicutes with potentially less diverse functions. Our findings demonstrate the utility of integrating space-for-time substitution with molecular profiling to predict long-term microbial responses to environmental change in vulnerable tropical ecosystems. Full article

This paper presents a novel submersible seaweed cultivation infrastructure designed to enhance seaweed growth through deep cycling. The system consists of a square grid of ropes for growing seaweed, supported by buoys, mooring lines, and innovative SubTractors—movable buoys that enable controlled submersion. The grid ropes are stabilized by four SubTractors, an array of small buoys, intermediate sinker weights and mooring lines anchored to the seabed. The SubTractors facilitate dynamic positioning, allowing the seaweed rope grid to be submerged below the thermocline—at depths of 100 m or more—where nutrient-rich deep water accelerates seaweed growth in offshore sites with low surface nutrient levels. Small buoys attached to the grid provide buoyancy, keeping the seaweed rope grid planar and near the surface to optimize photosynthesis when not submerged. This paper first describes the seaweed cultivation infrastructure, then develops a hydroelastic model of the proposed cultivation system, followed by a hydroelastic analysis under varying wave and current conditions. The results provide insights into the system’s dynamic behaviour, informing engineering design and structural optimization. Full article

This study investigates the effect of hydrogen embrittlement on the fracture toughness of 9% Ni steel and STS 316L stainless steel under cryogenic conditions ranging from −80 °C to −253 °C. Hydrogen charging was performed using electrochemical methods, and hydrogen uptake was quantitatively analyzed using thermal desorption spectroscopy (TDS). Fracture toughness was evaluated using crack tip opening displacement (CTOD) testing per ISO 12135, both without hydrogen (WO-H) and with hydrogen (W-H). The results showed a gradual decrease in CTOD values with decreasing temperature in both steels under hydrogen-free conditions, with ductile fracture maintained even at −253 °C. In contrast, hydrogen-charged specimens exhibited significant toughness degradation at intermediate subzero temperatures (−80 °C to −130 °C), particularly in 9% Ni steel due to its BCC crystal structure. However, at −160 °C and below, the effect of hydrogen embrittlement was suppressed mainly owing to the reduced hydrogen diffusivity. Scanning electron microscopy (SEM) analysis confirmed the transition from ductile to brittle fracture with decreasing temperature and hydrogen influences. At −253 °C, fully brittle fracture surfaces were observed in all specimens, confirming that at ultra-low temperatures, fracture behavior is dominated by temperature effects rather than hydrogen. These findings identify a practical temperature limit (approximately −160 °C) below which hydrogen embrittlement becomes negligible, providing critical insights for the design and application of structural materials in hydrogen cryogenic environments. Full article

Background: Adhesion to enamel is influenced by surface preparation, which affects the micromechanical retention of resin-based materials. Sodium hypochlorite (NaOCl) deproteinization has been proposed as a pretreatment to improve acid etching efficacy, but the optimal application time remains unclear. Methods: This in vitro study evaluated the effect of 5% NaOCl pretreatment at three exposure times (15, 30, and 60 s) on shear bond strength (SBS), the adhesive remnant index (ARI), and enamel etching patterns. Extracted human premolars (n = 140) were divided into four groups: the control (acid etching only) and three experimental groups. SBS was tested per ISO 11405, while ARI scores were assessed under stereomicroscopy, and surface morphology was examined by scanning electron microscopy (SEM). Results: The 30-s NaOCl group exhibited the highest SBS (20.9 MPa) compared with the control (15.9 MPa, p < 0.05) and 15-s (14.9 MPa, p < 0.05) groups. SEM analysis showed predominantly Type I–II etching patterns for the 30-s group, irregular Type III for 15 s, and overetched Type IV with loss of prism definition for 60 s, compromising the adhesive interface. ARI scores indicated 86.7% of samples in the 30-s group retained all adhesive on enamel (score 3). Conclusions: A 30-s 5% NaOCl pretreatment before acid etching improved enamel micromorphology and bonding performance compared to shorter or longer exposures. The intermediate duration provided effective deproteinization without structural damage, whereas prolonged exposure degraded the enamel microstructure. This protocol may offer a simple, cost-effective method to enhance clinical adhesive procedures, though prolonged exposure (60 s) should be avoided due to structural degradation of the enamel microstructure. Full article