Search Results (2,928)

Surface water-groundwater interaction zones are critical ecohydrological interfaces in arid regions, yet quantitative spatiotemporal patterns and soil-vegetation responses under coupled water-salt-heat gradients remain poorly documented. Based on a one-year monitoring period (August 2024–August 2025) at four sites along a river-to-desert transect (LW3: 25 m, LW2: 200 m, LW1: 300 m, LW4: 400 m from the Niya River) in the hyper-arid Tarim Basin, this study reveals the following quantitative patterns. Groundwater depth increased with distance from the river and followed an annual decrease-increase trend, with an anomalous shallow peak in March 2025 (−20 cm) linked to precipitation recharge. Soil temperature stability increased with depth: the 20 cm layer recorded the widest annual fluctuation (e.g., −1.5 °C to 24 °C at LW1), whereas the 80 cm layer varied only between approximately −0.2 °C and 28 °C. Proximity to the river dampened thermal extremes. Shallow soil moisture was highly dynamic (with a coefficient of variation [CV] reaching 40–50% at LW1 and LW4), while deeper layers remained stable; LW3 near the river stayed saturated year-round (CV = 0). Soil electrical conductivity (EC) decreased with distance from the river: LW3 exhibited the highest surface values (5000–16,000 μS cm⁻¹), whereas LW1 recorded the lowest (1000–2700 μS cm⁻¹). Vegetation performance was governed by coupled water-salt conditions rather than moisture alone: P. australis at LW1 achieved the tallest growth (>200 cm) and highest photosynthetic rates (20.25–37.38 μmol m⁻² s⁻¹), outperforming LW3 (104 cm, winter photosynthesis dropping to 2.01) and LW4 (~100 cm). Correlation analysis further showed strong vertical temperature coupling (r > 0.96 across all depths) and depth-stratified water-salt relationships (e.g., EC-volumetric water content r = 0.95 at 20 cm in LW4), reflecting spatial differentiation driven by freeze-thaw cycles, evaporative enrichment, and homogeneous silt-textured soils (54–96% fine fraction). These quantitative findings provide a detailed observational baseline for riparian ecohydrology in hyper-arid inland rivers and underscore that sustainable vegetation management requires balancing water availability against salinity stress. Full article

This work examines how well a Negative Derivative Feedback (NDF) controller suppresses vibration in a nonlinear electromechanical oscillator that is subjected to mixed excitations. Coupled nonlinear ordinary differential equations are used to model the system and show how mechanical and electrical components interact. The method of multiple scales (MMS) is used to develop analytical approximate solutions up to the second order, specifically for the primary resonance scenario. This study’s main contribution is a thorough bifurcation analysis and proof of the NDF controller’s high efficacy, which effectively lowers the first and second mode resonance amplitudes by roughly $99.8\%$ and $98\%$., respectively, with impressive reported effectiveness values of roughly 590 and 51.5. Additionally, the quantitative error analysis between the numerical simulation and the analytical approximation solution demonstrates a high degree of agreement, with a maximum error of less than ${10}^{-5}\%$ for the second mode and just $0.01\%$ for the first mode. Furthermore, we present the impact of parameters on FRCs. Frequency response curves (FRCs) are used in a thorough comparison analysis to assess the behavior of the system both before and after the controller is activated. A strong degree of connection between the analytical conclusions and numerical simulations carried out using the “fourth-order Runge–Kutta method” rigorously validates the accuracy of the perturbation analysis. Additionally, a performance benchmark between different control techniques, such as the NDF controller, Positive Position Feedback (PPF), and Linear Negative Position Feedback (LNPF), is shown in the paper. When compared to alternative approaches, the NDF controller shows the greatest reduction in oscillation amplitudes and higher robustness, as shown by transient response analysis (time history) at various time intervals. The outcomes validate the NDF approach’s dependability and efficiency in stabilizing intricate nonlinear electromechanical systems. The chaotic response and system periodicity were demonstrated through bifurcation diagrams and Poincaré maps. Full article

Size-exclusion chromatography (SEC) or gel-permeation chromatography (GPC) is an essential tool for determining the molecular weight and polydispersity of water-soluble polymers, including biopolymers used in hydrogels, sealants, bioinks, and other biomedical materials. However, aqueous SEC of polyelectrolytes, i.e., charged polymers, is often complicated by non-size interactions among polymer chains, porous column beads, pore surfaces, frits, tubing, and mobile phase. Salt addition to eluent is commonly used to screen these interactions, but the minimum salt concentration required to restore reliable SEC behavior remains poorly defined, and excessive salt may introduce tailing, refractive-index artifacts, deposits, or instrument concerns. In this study, aqueous SEC with refractive index (RI) and right-angle light scattering (RALS) detection was used to evaluate the effect of salt ($\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$) concentration on poly(ethylene oxide) (PEO), a nominally neutral reference standard polymer, and sodium alginate as a model anionic biopolymer. PEO retained a single bell-shaped peak across the tested salt range, but its elution volume and SEC/RALS-derived molecular weights varied slightly with salt concentration, showing that even a nominally neutral reference polymer is affected by mobile-phase conditions. Alginate showed much stronger salt dependence: eluent at very low salt concentration produced broad, noisy, and convoluted chromatograms, whereas increasing salt concentration progressively narrowed the main peak. The first condition that produced a clear, approximately symmetric RI/RALS main peak was $6.25\times {10}^{-3} \mathrm{M}$ $\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$, identifying it as the minimum effective salt concentration for this alginate/column/instrument system. To rigorously validate these observations, we propose a set of both qualitative and quantitative peak analyses that objectively confirm the optimal mobile-phase conditions. Ultimately, these results provide a practical workflow for identifying the minimum effective salt concentration required for reliable SEC analysis of water-soluble polymers. Full article

We introduce and study a class of multi-composite sigmoid neural network operators for Banach space-valued approximation. The proposed operators are generated by density-type kernels induced by finite compositions of seven standard sigmoid-type activation functions. The approximation is considered for continuous functions on compact intervals of the real line and on the whole real line, with values in an arbitrary Banach space $(X,\parallel ·\parallel )$. We prove quantitative pointwise and uniform convergence results by means of Jackson-type inequalities expressed through the first modulus of continuity. Higher-order and fractional approximation results are also obtained in terms of Banach space-valued derivatives and Caputo–Bochner fractional derivatives. The associated feed-forward neural network representation has one hidden layer and uses the multi-composite sigmoid function as its activation. Numerical experiments are presented to validate the theoretical estimates and to illustrate the approximation behavior of the proposed operators. In particular, we compare classical tanh-based operators, normalized self-composed activation operators, and heterogeneous multi-composite activation operators. The results show that self-composition and heterogeneous composition may improve the uniform approximation error for certain activation families and parameter choices, while also indicating that the observed improvement is activation-dependent and influenced by the composition order, kernel localization, and the regularity of the target function. Full article

During horizontal drilling in coal-rock gas reservoirs, the particle size distribution (PSD) of drilled cuttings directly affects drilling efficiency, hole cleaning, and wellbore stability. However, the evolution of cuttings PSD and its controlling mechanisms during coal-rock fragmentation remain insufficiently understood. In this study, a drill bit–coal-rock interaction model was established using the discrete element method (DEM) and calibrated against uniaxial compression experiments. The effects of weight on bit (WOB), rotational speed, and depth of cut (DOC) on cuttings PSD were quantitatively investigated. The results show that the relative influence on the maximum cutting size followed the order of DOC > WOB > rotational speed, whereas the influence on the average cutting size followed the order of rotational speed > WOB > DOC. Increasing DOC from 0.5 mm to 1.5 mm increased the maximum cutting size from 11.6 mm to 29.4 mm. Increasing WOB promoted the generation of medium- and large-sized cuttings, thereby increasing hole-cleaning requirements. Meanwhile, increasing rotational speed from 40 rpm to 90 rpm reduced the average cutting size and shifted the dominant cutting fraction from 4–6 mm to 1–4 mm. DEM observations reveal that cutting PSD evolution is jointly controlled by primary brittle fracture and secondary particle breakage through a five-stage fragmentation process involving stress concentration, microcrack initiation, crack propagation and coalescence, fragment detachment, and secondary fragmentation. Field validation using 146 cutting samples demonstrated the applicability of the proposed optimization strategy. Under the investigated drilling conditions, a DOC of approximately 0.5 mm and a rotational speed of 70–90 rpm were found to effectively limit oversized cutting generation. These findings improve the mechanistic understanding of cutting PSD evolution and provide practical guidance for drilling parameter optimization and hole-cleaning management in coal-rock gas horizontal wells. Full article

The oral pathogen Filifactor alocis encodes a repeats-in-toxin (RTX) protein, FtxA, that is encoded by the ftxA gene; it is present in approximately 50% of known isolated strains from various infected oral sites, including periodontitis, peri-implantitis, and root canal infections. It has been determined from PCR assessment of periodontally diseased cohorts in Ghana and Australia. Based on current knowledge, ftxA appears to be associated with both the progress and severity of periodontitis. This finding could potentially be linked to enhanced levels of ftxA-positive F. alocis, relative to ftxA-negative strain, and/or, in addition, a synergy between ftxA-positive strains and other periodontal pathogens. The exact mechanism remains unclear but may depend on an FtxA-mediated shifting of the host cell response toward immunosuppression. The main objective of the present work was to evaluate the prevalence and loads of F. alocis and the presence of ftxA in subgingival plaque in patients recruited for periodontal treatment in Sweden. This observational study included all samples that were received from external clinics over one full year (n = 71 patients). Our findings revealed that F. alocis was carried by 49 (69%) of the individuals, with the prevalence of ftxA amounting to 42.9% (n = 21). In 32 of the 71 samples, F. alocis could be quantitatively assessed. In this sub-population of F. alocis-positive patients, high loads of the bacterium were not related to age, and high loads were more frequently observed upon carriage of ftxA. The presence of, and co-colonization with, F. alocis with four additional periodontal pathogens was also evaluated. F. alocis was notable in that it co-colonized with all of the other species. Moreover, it was detected alongside two and even three of the other species within the same sample. Full article

To investigate the early-stage flame propagation and pressure response of premixed H₂-O₂ combustion under ultra-high-pressure constant-volume conditions, a transient CFD model was developed for a large-volume confined chamber. The numerical framework combines a density-based solver, the Peng–Robinson real equation of state, large eddy simulation, and a reduced H₂-O₂ chemical kinetic mechanism. Simulations were conducted at initial pressures of 30 and 40 MPa, H₂/O₂ molar ratios of 8:1 and 12:1, and three-, four-, and five-point ignition configurations. The results show that increasing the initial pressure from 30 MPa to 40 MPa advances the pressure rise onset from approximately 1.65 ms to 1.28 ms and increases the maximum pressure rise rate from 18.6 MPa·ms⁻¹ to 27.4 MPa·ms⁻¹ under the H₂/O₂ = 8:1 and three-point ignition condition. Under the investigated fuel-rich conditions, increasing the H₂/O₂ molar ratio from 8:1 to 12:1 delays the pressure rise onset from approximately 1.28 ms to 1.46 ms and reduces the maximum pressure rise rate from 27.4 MPa·ms⁻¹ to 21.1 MPa·ms⁻¹. For the 30 MPa and H₂/O₂ = 8:1 cases, the four-point ignition case produces the largest pressure rise rate of approximately 23.5 MPa·ms⁻¹, whereas the five-point ignition case shows a lower pressure fluctuation amplitude of approximately 3.6 MPa. The present conclusions are based on CFD quantitative engineering predictions and should be further validated using quantitative experimental measurements. Full article

Engineering computer graphics education frequently exhibits a gap between procedural CAD software (e.g. CATIA 2022) training and the strategic engineering reasoning required by industrial practice. This paper documents a holistic redesign of two advanced CAD courses. The study is framed within the Scholarship of Teaching and Learning (SoTL) tradition as a practitioner-led reflective case study. The redesign integrates four pedagogical mechanisms within an enterprise-CAD context: authentic problem-based learning, dual-layered asynchronous video scaffolding, software-agnostic heuristics (including pre-modelling cognitive mapping), and cognitive apprenticeship. The analysis triangulates three institutional data sources: quantitative Course Experience Survey indicators, qualitative student response themes, and twelve consecutive years of cohort-level academic performance records (2013–2024). The 2022 intervention iteration coincided with a marked elevation in academic performance. Grades reached approximately two standard deviations above the historical baseline. Concurrently, qualitative themes highlighted perceived industrial relevance and platform-portable confidence. However, performance in the post-intervention iterations (2023 and 2024) partially regressed. While scores remained above the historical mean, they did not sustain the 2022 peak. This pattern indicates partial sustainment, rather than evidence of a stable or definitive sustained pedagogical effect. This case is reported as descriptive rather than inferential. While the observed patterns align strongly with theoretical predictions, they do not establish definitive causal effects. Ultimately, the primary contribution of this study lies in documenting the integrated operationalization of these four mechanisms. Furthermore, it highlights longitudinal pedagogical sustainability as a critical, under-examined dimension that single-iteration evidence systematically obscures. Full article

Background/Objectives: Bile acid synthesis disorders (BASDs) represent a distinct category of progressive familiar cholestatic liver disease. A novel targeted mass spectrometry assay was developed for the accurate measurement of the major urinary atypical bile acids and bile alcohols that are biomarkers for HSD3B7, AKR1D1, CYP7B1 and CYP27A1 deficiencies, the four most common BASDs. Methods: Stable-isotope dilution UPLC tandem mass spectrometry was used for the simultaneous quantification of 12 key atypical bile acid biomarkers in urine from patients with BASD. Typical concentration ranges for these metabolites were established from urine samples from patients with biochemically and/or genetically confirmed BASD and compared with non-cholestatic and cholestatic controls. Results: The separation of major 3β-hydroxy-Δ⁵-bile acid sulfates, taurine- and glycine-conjugated 3-oxo-Δ⁴-bile acids, and bile alcohol glucuronides was achieved in a 20 min chromatographic run with intra- and inter-batch imprecisions of <15% for all metabolites. The mean ± SEM urinary concentration of total 3β-sulfated-Δ⁵-cholenoic acids in patients with HSD3B7 deficiency was 704 ± 204 µmol/L (n = 22), approximately 2000-fold higher than in cholestastic patients (n = 168) or non-cholestatic controls (n = 127). Similarly, the concentration of 5β-cholestane-3α,7α,12α,24,25-pentol-glucuronide, the major bile alcohol, in patients with CYP27A1 deficiency was 95 ± 17 µmol/L (n = 12). For CYP7B1 deficiency, two confirmed cases showed elevated levels (average, 7.5 µmol/L) of the glycine conjugate of 3β-sulfooxy-Δ⁵-bile acid. In AKR1D1 deficiency, total 3-oxo-Δ⁴-bile acids in urine were elevated (81 ± 16 µmol/L, n = 48), but concentrations showed overlap with cholestatic and non-cholestatic controls. Conclusions: A novel quantitative tandem mass spectrometry assay is described for the measurement of the major atypical metabolites and biomarkers in urine applicable to the accurate monitoring of treatment responses, and for the first time typical concentration ranges are established for each of these BASDs. Full article

Mineralising avian tendon is a widely used experimental model for studying collagen-guided mineralisation. Yet, the three-dimensional organisation and topology of its internal canal system have never been quantitatively characterised. We combined high-resolution micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) to provide the first morphometric and topological analysis of the canalicular network in mineralised turkey gastrocnemius tendon. micro-CT revealed that unmineralised canals occupy approximately 34.6% of the mineralised tissue volume and form a single continuously connected network (99.8% of void volume), with a connectivity density of ~1.3 × 10² mm⁻³, a fractal dimension of 2.58, a degree of anisotropy DA = 0.87 [BoneJ convention, range 0–1], and a closed-loop topology. SEM revealed marked ultrastructural heterogeneity of the mineral phase across fascicle cross-sections, consistent with graded intrafibrillar-to-interfibrillar deposition. These findings establish the first quantitative morphometric framework for physiologically mineralising collagen tissue and support the use of turkey gastrocnemius tendon as a tractable model for studying mineralisation dynamics, enthesis biology, and the design of biomimetic scaffolds with controlled porosity and anisotropy. Full article

Background: This narrative literature review aims to evaluate the evolution, current concepts, indications and clinical evidence of total scaphoid replacement as a treatment option for non-reconstructable scaphoid pathology. Particular emphasis is placed on implant design, materials, fixation strategies, and the biomechanical rationale underlying modern patient-specific prosthetic approaches. Methods: A comprehensive literature search was performed in PubMed, Scopus, Embase, and Google Scholar and was supplemented by reference screening and relevant book chapters. Studies reporting full scaphoid replacement were included, while partial replacements, non-original articles, and publications outside predefined languages were excluded. Data were synthesized qualitatively with respect to anatomy, biomechanics, implant materials, surgical techniques, fixation strategies, and clinical outcomes. Results: A total of 397 records were identified through database and manual searches. After removal of duplicates, non-topic-related articles, and non-retrievable studies, 33 publications were included in the final analysis. Early acrylic and silicone prostheses showed high complication rates, with implant removal required in up to 70% of early acrylic series and secondary procedures reported in approximately 24% of silicone implant cases. Radiographic abnormalities, including cyst formation and carpal malalignment, were reported in up to 43% of silicone implants despite acceptable short-term clinical outcomes. Modern metallic and patient-specific prostheses demonstrated improved resultsand implant removal required in a minority of cases. Functional outcomes, assessed by DASH and PRWE scores where available, showed significant postoperative improvement, and pain relief was reported in more than 90% of patients in larger titanium implant series. However, follow-up durations varied widely, ranging from 6 months to 43 years, and most studies consisted of small retrospective case series. Conclusions: Total scaphoid replacement has progressed from a spacer-based salvage concept to a patient-specific reconstructive strategy informed by anatomy and biomechanics. Quantitative evidence suggests that modern prostheses can achieve high rates of pain relief and acceptable complication profiles in carefully selected patients. Nevertheless, the current literature is limited by small sample sizes, heterogeneous methodologies, and a lack of long-term prospective data. Further studies with standardized outcome measures and dynamic assessment of wrist kinematics are required to define the long-term role of total scaphoid replacement. Full article

This study aimed to characterize metabolomic changes in the eye lens of senescence-accelerated OXYS rats in comparison with control Wistar rats, and to identify biochemical shifts associated with genotype, age, and cataract progression. Cataract severity was clinically graded. Rats’ lenses were analyzed using quantitative ¹H NMR spectroscopy at 3.6 and approximately 4.5 months of age. A total of 43 metabolites were quantified. We found that at 3.6 months of age, OXYS lenses exhibited a significant accumulation of 17 metabolites, primarily amino acids, compared to Wistar rats, suggesting an imbalance between amino acid uptake and crystallin biosynthesis. However, by 4.5 months, OXYS lenses exhibited rapid metabolic changes characterized by significant decreases in amino acid, glucose, and key energy/antioxidant markers, including NAD, adenylate energy charge, and hypotaurine. Clinical cataract grade (Grade 2 vs. 3) had a negligible impact on the overall metabolomic profile. Our results indicate that profound metabolic reorganization, including an initial amino acid excess followed by energy and antioxidant depletion, precedes the morphological manifestation of cataracts in OXYS rats. We suggest that a biochemical “point of no return” occurs early in cataractogenesis, while subsequent increase in lens opacification is a secondary consequence of preexisting metabolic disturbances. Full article

Although the long-term behavior of ground anchors depends fundamentally on interfacial behavior, the independent effect of the strand–grout interface on load loss has not been comprehensively investigated. This study establishes a physical model testing method that isolates the strand–grout interface and systematically investigates both short-term and long-term load loss behavior. Pull-out tests and long-term monitoring tests were conducted using grout uniaxial compressive strength ($q_u$ = 18–30 MPa) and bond length ($L_b$ = 900–1500 mm) as primary design variables. Long-term monitoring confirmed that prestress loss at the strand–grout interface is induced by the progressive pull-out displacement of the strand over time, following a logarithmic decay pattern. The load reduction coefficient n was significantly more sensitive to $L_b$ than to $q_u$; n increased sharply from 0.015 to 0.069 as $L_b$ decreased. Anchors with insufficient bond length exhibited secondary load reduction behavior that disrupted the stable log-linear decay, posing significant risk to long-term performance. Based on RMSE analysis of the fitted logarithmic model, a minimum monitoring period of approximately 50 days is recommended for reliable long-term prediction when bond length is adequate. These findings identify $q_u$ and $L_b$ as the governing parameters, providing a quantitative basis for optimizing prestress design and enhancing the long-term reliability of anchor systems. Full article

Earth-based materials are promising candidates for balancing thermal performance, hygrothermal regulation, and environmental sustainability. The objective of this study is to evaluate and compare the hygrothermal behavior of two earthen materials, structural cob and lightweight insulating earth, against conventional reference concrete, taking into account not only their insulating properties but also their ability to regulate coupled heat and moisture transfers. Experimental tests show a significantly higher hygroscopic buffering capacity for earth-based materials, with an MBV of 2.23 g/(m²∙%RH) for the structural material and 1.21 g/(m²∙%RH) for the insulation material, compared to less than 0.5 g/(m²∙%RH) for concrete. The sorption isotherms confirm distinct water storage behaviors, with an average sensitivity to relative humidity of 10.47% for the insulation material, compared to 3.8% for concrete and 2.25% for the structural material, in addition to an average reduction of 26% in the adsorption capacity between 23 °C and 45 °C for both earthen materials. Coupled heat–moisture simulations in COMSOL quantitatively demonstrate the hygrothermal superiority of bio-based materials over conventional concrete, as concrete promotes interstitial moisture accumulation due to its low vapor permeability. The parametric sensitivity analysis highlights the effect of hygrothermal properties, where diffusivity controls transport kinetics and sorption governs water storage, while thermal conductivity modulates the spatial redistribution of thermo-hygric fields. The next and final step made it possible to link the phenomena observed at the material scale to the actual energy performance of the building, confirming the potential of the double-wall cob + lightweight earth system to reduce heating and cooling requirements and maintain stable indoor comfort, where the annual heating demand is reduced by approximately 24% compared to the conventional prototype. Full article

Asymmetric SiC membranes with surface pore sizes ranging from 0.12 to 0.31 μm at a constant open porosity of approximately 42% were fabricated by dip-coating SiC support followed by sintering from 1700 to 2000 °C. The effect of membrane structural constants (hydraulic resistance (k₁), pore size exponent (k₂), and shape factor (k₃)) on PWP were evaluated by comparing the symmetric and asymmetric structures. In addition, the experimentally determined values of PWP were quantitatively analyzed by comparing with theoretically predicted values obtained using the Kozeny–Carman (K–C) and Hagen–Poiseuille (H–P) models. Despite having a smaller pore size, the asymmetric membranes exhibited high PWP (1257-3883 LMH) due to decreased flow resistance (low k₁), enhanced pore size effect (high k₂), and improved flow network (high k₃) as compared to symmetric membranes. The hydrophilicity of the prepared membranes improved remarkably, with increasing average surface roughness (102.3 nm to 161.0 nm) due to an increase in pore size, which also caused a decrease in water contact angle (WCA) from approximately 27.44° to 21.67° with increasing sintering temperature (1700–2000 °C). Furthermore, the prepared membrane separation performance was found to be affected by its pore size, and the 1900 °C sintered SiC membrane showed optimal gradient profile and pore structure, demonstrating its practical reusability and scalability for O/W wastewater treatment. Full article