Search Results (1,618)

Soil water availability, salinity dynamics, and nitrate transport are key factors controlling agricultural sustainability in arid environments characterized by limited water resources and high evaporative demand. This study evaluated the combined effects of soil texture, nitrate–nitrogen application, and sawdust mulching on soil water retention, evaporation losses, salinity redistribution, and nitrate movement in loamy sand and sandy clay loam soils under controlled greenhouse conditions. Results showed that soil texture was the dominant control on hydrochemical behavior, with sandy clay loam exhibiting higher water retention and lower drainage than loamy sand. Sawdust mulching significantly improved soil water conservation by reducing evaporation and stabilizing moisture distribution, while the 4 cm mulch treatment achieved the highest overall CSI performance. Evaporation strongly governed salinity accumulation in surface layers, whereas mulching reduced salt build-up and promoted a more uniform salinity profile. Nitrate transport closely followed water fluxes, resulting in higher leaching in loamy sand and greater retention in sandy clay loam. Increasing nitrogen application enhanced nitrate mobility and leaching in both soils. A Composite Sustainability Index (CSI) was developed to integrate soil water conservation, evaporation reduction, salinity control, and nitrate retention into a unified metric. Sensitivity analysis demonstrated that treatment rankings were largely unaffected by alternative weighting schemes, confirming the robustness of the CSI framework. The CSI identified mulch application, particularly the 4 cm mulch treatment, as the most effective management option based on overall sustainability performance. The CSI framework provides an integrated decision-support tool for evaluating coupled water–salt–nitrate interactions and improving water use efficiency and salinity management in arid agricultural systems. This study offers a novel integrated CSI-based framework for simultaneously quantifying hydrological and hydrochemical soil responses under mulch management in arid environments. Full article

Ambient-curing epoxy–urethane reactive polymer composites require a balance between initial flowability and subsequent structure buildup. In this study, epoxy–urethane reactive polymer composites containing precipitated calcium carbonate were prepared and referred to as EUPC formulations. Their rheological evolution was characterized by flow sweep, temperature sweep, time sweep, three-interval thixotropy tests (3ITT), amplitude sweep, and oscillatory time sweep. The formulations exhibited distinct initial flow resistance and strong temperature sensitivity, with apparent viscosity decreasing as temperature increased. During ambient curing, viscosity increased continuously, indicating progressive rheological buildup under the selected testing conditions. The 3ITT results showed high-shear-induced apparent viscosity reduction followed by recovery-stage viscosity evolution after returning to the low-shear condition, indicating that the recovery index should be interpreted as an apparent post-shear recovery index rather than a purely thixotropic recovery parameter. Oscillatory measurements revealed a gradual transition from viscous-dominated to more elastic-dominated behavior, and the apparent gel time followed the sequence EUPC-2 < EUPC-4 < EUPC-1 < EUPC-3 < EUPC-5 < EUPC-6. These results indicate that EUPC processability and structure buildup should be evaluated by integrating initial viscosity, temperature sensitivity, post-shear response, and operational viscous-to-elastic transition. Full article

Lost circulation in fractured formations is a major challenge during drilling operations, while conventional plugging evaluation methods relying solely on pressure-bearing curves and fluid-loss data often fail to accurately distinguish effective internal plugging from ineffective plugging behavior. To address this issue, a visualized plugging evaluation apparatus with high pressure-bearing capacity and large-window observation capability was developed to directly observe the plugging process and evaluate plugging performance under different fracture conditions. Based on the Ideal Packing Theory and the D₉₀ rule, plugging formulations were systematically evaluated under different fracture-width coefficients, slurry concentrations, and fracture-width conditions. The results showed that excessively large fracture-width coefficients or excessively high slurry concentrations could lead to premature “external plugging,” in which plugging materials accumulated near the fracture entrance without forming effective internal plugging structures. Although such cases exhibited rapid pressure buildup, visual observations confirmed that the fracture itself remained insufficiently sealed. Under the present experimental conditions, the optimized formulation with a fracture-width coefficient of 0.8 W and a slurry concentration of 25% exhibited the best overall plugging performance. The formulation reached 10 MPa in approximately 2650 s and successfully formed stable internal plugging structures under different fracture-width conditions, with the maximum variation in plugging time remaining within 7%. Field applications in Well BD-X further validated the effectiveness of the proposed method and optimized formulations under real drilling conditions. The developed apparatus and evaluation method provide a reliable experimental approach for optimizing plugging formulations and preventing lost circulation in fractured formations. Full article

Fruit color is a key quality indicator for apples and directly influences their market value. The process of fruit ripening encompasses various physiological and biochemical changes, such as the breakdown of chlorophyll and the buildup of anthocyanins and carotenoids. This study investigated the mechanism of chlorophyll degradation in apple peels using ‘Granny Smith’ varieties. The experiments involving the treatment with methyl jasmonate (MeJA) indicated that a concentration of 10 µM MeJA led to a reduction in chlorophyll degradation, while a higher concentration of 1500 µM MeJA enhanced this degradation, which aligned with the variations observed in the expression of genes associated with chlorophyll degradation. The key chlorophyll degradation gene MdSGR1 was cloned and found to be induced by methyl jasmonate. MdSGR1 encodes a 283-amino-acid protein belonging to the stay-green superfamily. The promoter possesses inducible cis-acting elements that respond to methyl jasmonate, low temperature and light, while the protein is localized to chloroplasts. Overexpression and silencing vectors were constructed. Overexpression of MdSGR1 induced chlorosis in tobacco leaves and ‘Granny Smith’ apple peels, decreased chlorophyll content, and upregulated related gene expression. Conversely, silencing MdSGR1 produced opposite effects. Arabidopsis thaliana plants overexpressing MdSGR1 exhibited low chlorophyll content, reduced photosynthetic rate, upregulated expression of genes associated with chlorophyll degradation. The results of yeast one-hybrid and dual-luciferase reporter assays indicated that the MdMYC2 transcription factor interacts with the promoter region of MdSGR1. In conclusion, MdSGR1 is crucial for the degradation of chlorophyll in apple peel, and it is regulated both by the MdMYC2 transcription factor and different concentrations of MeJA. This study preliminarily elucidated the regulatory mechanism of methyl jasmonate on chlorophyll degradation in fruit peel, and these findings provide an important theoretical basis for controlling degreening and color quality in apple fruit. Full article

This study evaluated the retention force between milled polyetheretherketone (PEEK) posts with different surface treatments and resin composites for core build-up, and the effect of thermal cycling on the retention force. Four groups of PEEK posts were prepared: untreated group (NT), mechanically treated group with sandblasting (SB), chemically treated group with primer application (AD), and a group combining mechanical and chemical treatments (SB+AD). Pull-out tests were conducted on these groups. The specimens were divided into two subgroups: one stored in a humid environment at 37 °C for one week (TC0) and the other subjected to 10,000 cycles of thermal cycling between 5 °C and 55 °C (TC10,000). Data were analyzed using two-way ANOVA and Tukey’s test. Additionally, the effect of thermal cycling on each group was examined using Student’s t-test. Both surface treatment and thermal cycling factors had statistically significant effects on retention force (p < 0.05). The interaction between these factors was also statistically significant (p < 0.05). The results showed that the retention force of the treated groups was significantly improved compared to the untreated group, with the SB+AD group exhibiting the highest retention force, followed by the SB group and then the AD group. Thermal cycling did not affect the retention force in the NT, SB, and SB+AD groups. These findings suggest that the combination of mechanical and chemical surface treatments is the most effective method for improving the retention force between PEEK posts and resin composites for core build-up. Furthermore, appropriate surface treatment of PEEK posts may influence their long-term durability. Full article

The second most prevalent neurodegenerative illness in the world, Parkinson’s disease (PD), currently has no viable treatments. Although it is yet unknown if mitochondrial dysfunction is an initial event or evolves as a result of neurodegeneration, it is thought to be a crucial component of Parkinson’s disease etiology. From the perspective of mitochondrial quality control (MQC), which includes PINK1/Parkin-mediated mitophagy, mitochondrial dynamics, and mitochondrial proteostasis, this article examines mitochondrial dysfunction. Together, these processes preserve mitochondrial homeostasis and prevent the buildup of damaged mitochondria. Dysfunctional mitochondria gradually build up and cause oxidative stress and aberrant cellular signaling when mitochondrial quality control is compromised. According to available data, mitochondrial reactive oxygen species (mtROS) primarily worsen pre-existing mitochondrial damage by encouraging α-synuclein aggregation, cardiolipin remodeling, and dopamine oxidation. In addition, innate immune pathways like cGAS–STING and TLR9 signaling can be triggered by mitochondrial damage-associated molecular patterns (mtDAMPs), especially mitochondrial DNA, which can lead to long-term neuroinflammatory reactions in PD. While new research suggests that m⁶A RNA modification may be involved in the regulation of mitochondrial stress, the PINK1/Parkin pathway is crucial for maintaining mitochondrial homeostasis. Therapeutic approaches that target mitophagy augmentation, neuroinflammatory signaling, and mitochondrial protection have garnered increasing attention. In an attempt to improve mitochondrial function and lessen persistent neuroinflammatory activation, future research will probably need to concentrate on combination treatment techniques. Full article

This research provides new insights into the materials, methods of application and modification of the black lines used by Piet Mondrian (1872–1944) in his Neoplastic works. Interesting information was gained from letters and studio photographs, the making of mock-ups and reconstructions, and the in-depth study of four paintings, dated between 1921 and 1938, in the collection of Fondation Beyeler (Riehen/Basel, Switzerland)—Tableau I (1921–1925), Composition with yellow and blue (1932), Composition with double line and blue (1935) and Picture no. III (1938)—as well as the examination of an unfinished painting, Composition with red (1934, private collection). The four paintings were investigated with high-magnification stereomicroscopy, technical photography in transmitted light and raking light, X-rays and infrared reflectography. Detailed information about the buildup and composition of the layers was gathered with the study of cross sections and microsamples, using optical microscopy and chemical analyses. It was shown that Mondrian frequently moved the lines and changed their width up to the very last working phase and, probably, did not use a ruler in the traditional sense to achieve straight lines. In one of the works, Mondrian even employed a pencil, tracing a groove in the wet paint to accentuate straight edges. The black lines consist of multiple paint layers of diluted bone black oil paint, added with small amounts of coloured paint, alternated with thin oil-resin layers, sometimes containing lead white particles. Finally, a thin (pigmented) oil-resin finish was applied on top of the black line. Full article

With increasingly stringent restrictions on SF₆ greenhouse gas emissions, C₄F₇N-based gas mixtures have attracted considerable attention as promising alternatives for high-voltage circuit breakers; however, their relatively weaker arc-quenching capability poses significant challenges for interruption chamber design at high voltage levels. In this study, a 3.5% C₄F₇N/83.5% CO₂/13% O₂ gas mixture was used as the arc-extinguishing medium in a 550 kV environmentally friendly gas circuit breaker. Based on a magnetohydrodynamic (MHD) model considering PTFE nozzle ablation effects, systematic optimization studies were conducted on key structural parameters of the puffer-type interruption chamber, including the exhaust hole diameter, nozzle throat diameter and length, arcing contact diameter, and downstream expansion angle. Simulations under arcing times of 9.9 ms and 11.4 ms were performed to evaluate chamber pressure, axial temperature, extinction peak voltage, and post-arc conductance characteristics. The results indicate that extending the nozzle throat straight section to 70 mm, enlarging the exhaust hole, and increasing the moving contact radius can effectively enhance pressure buildup, reduce arc-core temperature, and improve dielectric recovery capability. Under the 11.4 ms arcing condition, the optimized structure achieved an extinction peak voltage of 6972.4 V and a G200 value of 0.731 ms, demonstrating substantially improved interruption performance. These findings reveal the synergistic relationship between arcing time and structural parameters and provide theoretical guidance for the engineering design of environmentally friendly high-voltage gas circuit breakers. Full article

The Late Triassic Bolila Formation in the central Qiangtang Basin is a typical carbonate buildup deposited during a regional transgression in the eastern Tethyan realm. Understanding its sedimentary evolution and reservoir-forming mechanisms is crucial for hydrocarbon exploration. This study integrates petrology, detrital zircon U-Pb geochronology, carbon-oxygen isotopes, and reservoir property analysis of the Quemudongda section. The results show: (1) detrital zircon dating provides a maximum depositional age of 225.7–235.7 Ma (Carnian–Norian), correcting the previous Jurassic misassignment on the 1:250,000 geological map. Carbon-oxygen isotopes (average δ¹³C = +3.2‰, δ¹⁸O = −11.1‰) are consistent with the global Carnian–Norian positive δ¹³C excursion. (2) The section reveals a platform-margin reef (hexactinellid and calcareous sponges) and slump breccia (seven layers) association, representing a steep-rimmed carbonate platform margin. The sedimentary evolution comprises three stages: reef initiation, reef flourishing with frequent slumping, and reef decline with dolomitization. (3) Reservoirs are mainly breccia and reef dolostones, with intergranular, intercrystalline, and fracture-related pores. Porosity averages 2.8% (0.8%–7.2%), permeability averages 0.35 mD (0.001–8.5 mD), defining a low-porosity, ultra-low-permeability fracture-pore reservoir. Breccia dolostone has better properties (porosity 3.71%, permeability 2.412 mD). (4) Reservoir formation is controlled by sedimentation (platform-margin facies), diagenesis (dolomitization generates pores, but high-temperature recrystallization causes densification), and tectonics (microfractures enhance permeability). High-quality reservoirs occur where breccia dolostone and fractures overlap. (5) The Bolila reef-shoal complex and the overlying Bagong Formation source rocks form a “lower reservoir—upper source” assemblage, representing a new exploration target in the Tuonamu area. The breccia dolostone–fracture overlap zone is the core “sweet spot”. Full article

This study aimed to assess the effect of etching protocols on the bonding performance of three universal adhesives to dentin under different aging conditions. Specimens were obtained from human molars and randomly allocated to 6 groups (n = 10) according to adhesive type (Clearfil S3 Bond Universal (CBU), Clearfil Universal Bond Quick (CUBQ), and Zipbond Universal (ZBU)) and application strategy (self-etch or etch-and-rinse). Each adhesive was applied according to the manufacturer’s instructions for the respective strategy, followed by composite resin build-up. Resin–dentin beams were prepared and subjected to three aging conditions: storage in distilled water at 37 °C for 24 h, 10,000 thermocycles, or pH cycling. Microtensile bond strength was measured, and the degree of conversion was evaluated using Fourier-transform infrared spectroscopy. Data were evaluated using analysis of variance and Weibull statistics (α = 0.05). Both adhesive type and application protocol significantly influenced bond strength (p < 0.05), whereas aging conditions had no significant effect (p > 0.05). At 24 h, ZBU in the etch-and-rinse strategy showed the highest bond strength and significantly outperformed CUBQ. After thermocycling and pH cycling, no significant differences were found among adhesives. All adhesives demonstrated higher reliability when used in the self-etch mode. Weibull analysis indicated that ZBU in the self-etch mode had the lowest probability of failure, with fractures occurring at higher stress levels. CUBQ showed the lowest degree of conversion. Full article

This study investigates the fracture development and caving mechanisms in longwall coal mining using powered roof supports (PRSs), simulated with the Finite–Discrete Element Method (FDEM) in Geomechanica’s Irazu platform. It is presented as an application study demonstrating the ability of this established FDEM platform to simulate fracture evolution and caving in a longwall environment, rather than as the development of a new model, criterion, or algorithm. A numerical model of a longwall face, including canopy, shield, and base components, was constructed in SolidWorks and imported for simulation. Fractured and intact coal zones were defined, and boundary conditions were applied to represent the mining advance sequence. Stress redistribution, fracture initiation, and subsequent caving behind supports were analyzed both with Irazu’s native tools and through advanced visualization in ParaView. Results revealed that fracture initiation occurs at the roof–canopy interface, propagating towards the gob and floor, eventually forming an elliptical caving pattern. Stress analysis highlighted critical loading at both canopy–roof and base–floor contacts, consistent with patterns reported in field and theoretical studies. Energy maps reveal elastic energy buildup prior to first break and its stepwise release during fracture propagation and caving. This application demonstrates the potential of FDEM to capture both the mechanical response of supports and the evolution of coal fractures, offering valuable insights for optimizing support design and ensuring roadway stability. These findings contribute to improved prediction and management of strata behavior in underground coal mining, bridging numerical modeling with practical engineering applications. Full article

Salinity stress severely inhibits crop growth and reduces yield. Exogenous selenium (Se) enhances plant abiotic stress tolerance, but how different selenium forms exert their impacts and pathways in mitigating salinity remains ambiguous. Under salt stress, this work compared two Se forms, selenate [Se(VI)] and selenite [Se(IV)], regarding their impacts on development, photosynthetic performance, antioxidative system, osmotic regulators, Se buildup, and stress-related gene expression in Nicotiana tabacum L. Both Se species significantly promoted tobacco growth. (1) Under 150 mmol/L NaCl stress, biomass, net photosynthetic rate and antioxidant enzyme activities decreased significantly, while soluble sugar, free proline, Na⁺/K⁺, Na⁺/Ca²⁺, H₂O₂, MDA contents and NtROS2a, NtLEA5 expression increased significantly. (2) Exogenous Se increased biomass, photosynthetic parameters; antioxidant enzyme activities and NtNAC2, NtCDPK12, NtROS2a expression; elevated Se deposition in roots and leaves; and reduced oxidative damage, ion imbalance and NtLEA5 expression in salt-stressed tobacco, suggesting that Se may improve salt tolerance by regulating these physiological processes and stress-related gene expression. (3) Compared with Se(IV), Se(VI) significantly increased root length, chlorophyll content, stomatal conductance, K⁺ content, SOD/CAT activities, leaf and root Se accumulation as well as and NtNAC2, NtCDPK12 expression, while Se(IV) resulted in higher root diameter, free proline content, Na⁺/K⁺ ratio and NtROS2a expression. In conclusion, both sodium selenate and sodium selenite effectively enhanced tobacco salt tolerance. The salt stress alleviation effect of Se(VI) may be associated with upregulating NtNAC2 and NtCDPK12 to improve antioxidant capacity and photosynthesis, thereby potentially maintaining cell membrane integrity and ion balance, while Se(IV) may exert its effect through upregulating NtROS2a to promote root thickening, reactive oxygen species scavenging and osmotic adjustment. At the tested concentrations, selenate was more effective. Full article

Metabolic dysfunction and proteinopathy are hallmarks of neurodegenerative disease, yet their mechanistic interplay remains poorly understood. Here, we show that loss of the neuronal NAD⁺-synthesizing enzyme Nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) disrupts amyloid precursor protein (APP) processing in cortical neurons, leading to accumulation of APP C-terminal fragments (APP-CTFs). NMNAT2 deficiency lowers the NAD⁺/NADH redox ratio coincident with APP-CTF buildup. Temporal profiling reveals a biphasic increase in APP-CTFs, with an initial gradual rise followed by rapid accumulation, paralleling the expansion of differentially expressed proteins. Pathway analysis indicates early activation of JNK/MAPK signaling, followed by late-stage suppression of mitochondrial pathways and induction of endoplasmic reticulum stress and unfolded protein response programs. Seahorse analyses reveal early glycolytic impairment followed by deficits in mitochondrial respiration. Knockdown of the NAD⁺ hydrolase sterile alpha and TIR motif-containing protein 1 (SARM1) restores mitochondrial function and normalizes APP-CTF levels in NMNAT2 knockout neurons, whereas NAD⁺ supplementation provides only modest rescue. Together, these data demonstrate that neuronal NAD⁺ depletion drives progressive, SARM1-dependent disruption of glucose metabolism and proteostasis, impairing APP processing. The NMNAT2–SARM1 axis thus links metabolic stress to proteinopathy and highlights SARM1 as a central mediator of neurodegenerative dysfunction. Full article

The present work focuses on the nonlinear seismic response of transmission tower systems when subjected to successive earthquake ground motions. To this end, nonlinear time-history analyses were carried out by applying multiple ground motion records in sequence, thereby replicating realistic scenarios in which structures endure repeated seismic loading during and following major earthquakes. The structural behavior was examined through two distinct modeling frameworks: a pinned configuration, where tower members are considered to resist axial forces only, and an SSI-based model, which captures the interaction between the structure and the supporting soil. Both frameworks were assessed in terms of several critical response quantities, namely peak displacements, permanent displacements following each seismic event, acceleration demands, and base shear forces developed at the foundation level. The comparative evaluation of the two models brought to light considerable discrepancies in the computed response, confirming that the dynamic characteristics of the soil and its coupling with the structure have a pronounced effect on the overall seismic performance of transmission towers. In addition, it was shown that the cumulative effect of successive seismic excitations drives a gradual buildup of deformations, yielding displacement demands that far exceed those obtained from conventional single-earthquake analyses. These outcomes point to the necessity of incorporating SSI and multi-sequence seismic loading into both the design and the seismic assessment of transmission infrastructure, as approaches relying solely on single-event excitation are likely to significantly underestimate the true seismic demand imposed on such structures. Full article

Fractured–vuggy carbonate reservoirs are characterized by highly discrete storage structures, and the number, spatial distribution, and volume of cavities strongly affect well-test responses and reservoir development decisions. This study develops a PEBI-grid finite-volume implementation of a wave–seepage-coupled model for pressure-transient interpretation in reservoirs containing irregular cavities. The objective is not to introduce a new general-purpose finite-volume method but to embed irregular cavities as special control volumes into a locally orthogonal PEBI grid so that the cavity volume, geometry, and well–cavity distance can be represented explicitly in bottom-hole pressure calculations. The model is formulated as a thickness-averaged two-dimensional system in which the fracture–matrix region is treated as an equivalent seepage continuum, and each cavity is assigned a spatially uniform pressure governed by a wave–seepage exchange relation. For the limiting case of zero cavity volume, the numerical bottom-hole pressure agrees closely with the analytical solution and the material-balance estimate. A further cylindrical-cavity benchmark against an analytical wave–seepage solution gives a pressure-drawdown relative L2 error of 4.38%, where the relative L2 error denotes the Euclidean norm of the pressure error vector normalized by that of the reference solution, providing additional validation of the cavity-coupled formulation. Sensitivity analysis shows that increasing the cavity volume delays the characteristic extrema of the pressure derivative and strengthens the contrast between the minimum and maximum, whereas increasing the well–cavity distance mainly shifts the onset of the cavity-dominated response and weakens its amplitude. A field pressure-buildup case from the Fuyuan oilfield is interpreted using the proposed workflow. The matched model indicates a pentagonal cavity with a volume of 169,770 m³, a well–cavity distance of 158.4 m, a permeability of 5.535 md, and an initial reservoir pressure of 86.66 MPa. The results demonstrate that the proposed PEBI-FVM wave–seepage-coupled model can support practical well-test interpretation of irregular cavities, while its reliability depends on the validity of the equivalent-continuum and uniform-cavity-pressure assumptions. Full article