Search Results (5,752)

The process of exploiting hydrocarbon deposits is subject to many complications, some of which can make exploitation very difficult or impossible. These factors include damage to the wellbore zone by drilling fluid, which impedes the flow of reservoir fluid from the production zone to the well. This article presents the results of research conducted to develop drilling fluid compositions with the best possible ability to form a tight sealing sediment on the borehole wall. In addition to traditional carbonate blockers, modern organic agents were used as bridging agents. Research was conducted on the selection of the drilling fluid composition, the rheological parameters of which would ensure the suspension of the solid phase in the form of various types of blockers. After preparing the base drilling fluid, its composition was modified by adding different configurations of blockers. The sets of blockers added to the fluid varied in both chemical structure and particle size. Such modified fluids were then subjected to tests of technological properties, such as rheological parameters, API filtration, and pH. In the next stage, sealing tests of the filter cake formed by the tested fluids were carried out on the surface of the rock core using the PPT—Pore Pressure Transmission Test. Based on the obtained results, it can be concluded that the new type of organic blockers used allows the rapid formation of a tight filter cake on the borehole wall, and thus significantly reduces drilling fluid filtration. During PPT, the sediment formation time (t_pmax) for OB2 was 45 min; for the combination of OB1 and the carbonate inhibitor, it was 8 min; and for the carbonate inhibitor alone, it was 150 min. Full article

Formation damage caused by wellbore fluids remains a key concern in carbonate reservoirs, where pore plugging and filtrate invasion can severely reduce permeability. This study investigates the influence of filtrate-control components in cellulose-based polymeric fluids on the potential for formation damage in carbonate rocks and evaluates the performance of HPA starch as an alternative to cellulose, focusing on its comparative effects on formation permeability. Experimental tests were performed using Indiana Limestone cores to measure filtration behavior and permeability recovery after exposure to different polymeric solutions. The results revealed distinct mechanisms associated with each additive: PAC LV controlled fluid loss mainly by adsorption and pore plugging, while HPA starch formed more deformable and permeable structures. Glycerin, when used alone, did not induce formation damage but increased fluid viscosity, favoring more stable dispersion of the polymeric phase. Micronized calcite enhanced external cake consolidation through particle bridging. The combined use of PAC LV, glycerin, and calcite provided the most efficient filtration control and minimized formation damage. These findings contribute to understanding the isolated and synergistic roles of filtrate-control agents and support the design of optimized polymer-based fluids for well intervention and abandonment operations. Full article

Macroscopic fatigue tests, mesoscopic finite element simulations, and microscopic molecular dynamics simulations were composed to study the damage and failure of drainage asphalt mixtures in multiscale. The applicability of the fatigue models fit by strain, stress, and the linear fitting slope of the indirect tensile modulus curves were compared. The mesoscopic damage and failure distribution and evolution characteristics were studied, considering the single or coupling effect of traffic loading, hydrodynamic pressure, mortar aging, and interfacial attenuation. The microscopic molecular mechanism of the interface adhesion failure between the aggregate and mortar under water-containing conditions was analyzed. Results show that the fatigue model based on the linear fitting slopes of the indirect tensile modulus curves has significant applicability for drainage asphalt mixtures with different void rates and gradations. The damage and failure have an obvious leap development when traffic loading increases from 0.7 MPa to 0.8 MPa. The hydrodynamic pressure significantly increases the stress of the mortar around the voids and close to the aggregate, promoting damage development and crack extension, especially when it is greater than 0.3 MPa. With the aging deepening of the mortar, the increase rate of the damage degree gradually decreases from the top to the bottom of the mixture. With the development of interfacial attenuation, the damage and failure of interfaces continue increasing, while that of the mortar increases first and then decreases, which is related to the loading concentration in the interface and the stress decrease in the mortar. Under the coupling effects, whether the cracks mainly generate in the mortar or interface depends on their damage degrees, thus causing the stripping of the aggregate wrapped or not wrapped by the mortar, respectively. The van del Waals force is the main molecular effect of interface adhesion, and both acidic and alkaline aggregate components significantly tend to form hydrogen bonds with water rather than asphalt, thus attenuating the interface adhesion. Full article

Numerical simulations, unlike experimental studies, eliminate material and setup costs while significantly reducing testing time. In this study, a random distribution program for steel-recycled polyethylene terephthalate hybrid fiber recycled concrete (SRPRAC) was developed in Python (3.11), enabling direct generation in Abaqus. Mesoscopic simulation parameters were calibrated through debugging and sensitivity analysis. The simulations examined the compressive failure mode of SRPRAC and the influence of different factors. Results indicate that larger recycled coarse aggregate particle sizes intensify tensile and compressive damage in the interfacial transition zone between the coarse aggregate and mortar. Loading rate strongly affects outcomes, while smaller mesh sizes yield more stable results. Stronger boundary constraints at the top and bottom surfaces lead to higher peak stress, peak strain, and residual stress. Failure was mainly distributed within the specimen, forming a distinct X-shaped damage zone. Increasing fiber content reduced the equivalent plastic strain area above the compressive failure threshold, though the effect diminished beyond 1% total fiber volume. During initial loading, steel fibers carried higher tensile stresses, whereas recycled polyethylene terephthalate fibers (rPETF) contributed less. After peak load, tensile stress in rPETF increased significantly, complementing the gradual stress increase in steel fibers. The mesoscopic model effectively captured the stress–strain damage behavior of SRPRAC under compression. Full article

Understanding the microstructure–property relationship in aluminum extrusions is crucial to leverage their potential in automotive lightweighting. The sensitivity of the processing history to the microstructure and through-thickness variations poses a major challenge since it leads to strong directionality in plasticity and fracture. Reliable characterization of the mechanical response under relevant stress states is crucial for the development of modeling strategies and performance ranking in alloy design. To this end, tensile and 3-point bend tests were performed for an aluminum extrusion produced on a laboratory-scale extrusion press at Rio Tinto Aluminium. Direct measurements of surface strains during bending using stereoscopic digital image correlation revealed that a larger bend angle in the VDA238-100 test does not necessarily imply a higher fracture strain. The T4 sample tested in the extrusion direction sustained a bend angle of 104° compared to 68° in T6 for the same nominal bend severity (ratio of sheet thickness to punch radius), despite comparable major fracture strains of 0.60 and 0.58, respectively. It is proposed that the work-hardening behavior governs the strain distribution on the outer bend surface. The higher hardening rate in the T4 condition helped distribute deformation in the bend zone more uniformly. This delayed fracture to larger bend angles since strain is accumulated at a lower rate. To assess whether the effect of the hardening behavior is manifest at a microstructural lengthscale, microcomputed tomography (μ-CT) scans were conducted on interrupted bend samples. The distribution and severity of damage in the form of cracks on the outer bend surface were distinct to the temper and thus the hardening rate. Full article

This study investigates the thermoelastic frictional contact and wear behavior during reciprocating sliding of a conductive cylindrical punch on a functionally graded piezoelectric material (FGPM)-coated half-plane. The thermo-electro-elastic properties of the coating vary continuously along the thickness direction according to arbitrary gradient functions, with thermal parameters being temperature-dependence. A theoretical framework for the coupled thermo-electro-elastic frictional contact problem is developed and solved using the finite element method. A sequential coupling approach is employed to integrate thermoelastic frictional contact with piezoelectric effects. Furthermore, wear on the coating surface is modeled using an improved Archard formulation, accounting for its impact on thermal sliding frictional contact characteristics. Numerical simulations examine the influence of wear, cycle number, friction coefficient, gradient index and gradient form on the coupled thermo-electro-elastic response of the FGPM coating structure. The numerical results demonstrate the gradient index and gradient form can effectively mitigate thermo-electrical contact-induced damage and reduce friction and wear in piezoelectric materials. Full article

Granulosa cell ferroptosis is a critical factor in follicular atresia and premature ovarian insufficiency (POI). As a regulated form of programmed cell death, ferroptosis is gaining significant attention in reproductive medicine research. MicroRNAs (miRNAs) play a crucial role in regulating key aspects of ferroptosis, including the glutathione-GPX4 pathway, glutamate/cystine transport, and iron and lipid metabolism. The present study demonstrates that miR-26a positively modulates ferroptosis by targeting SLC7A11, a member of the solute carrier family. We found that oocytes and granulosa cells are susceptible to the ferroptosis inducer erastin, and employed RNA sequencing to delineate the miRNA expression profiles during erastin-induced damage and ferroptosis. Notably, miR-26a expression was significantly upregulated in erastin-treated oocytes. Importantly, overexpression of miR-26a promoted ferroptosis in granulosa cells, while its knockdown inhibited this process. Ectopic miR-26a expression suppressed SLC7A11, thereby increasing ferroptosis. Our findings indicate that miR-26a influences ferroptosis by inhibiting glutathione synthesis, reducing cellular antioxidant capacity, and suggesting a potential strategy to enhance reproductive potential. Full article

Diabetic nephropathy (DN) remains the leading cause of end-stage renal disease worldwide, with proximal tubular epithelial cells (PTECs) playing a central role in its pathogenesis. Under hyperglycemic conditions, PTECs drive a pathological triad of inflammation, apoptosis, and fibrosis. Recent advances reveal that these processes interact synergistically to form a self-perpetuating vicious cycle, rather than operating in isolation. This review systematically elucidates the molecular mechanisms underlying this crosstalk in PTECs. Hyperglycemia induces reactive oxygen species (ROS) overproduction, advanced glycation end products (AGEs) accumulation, and endoplasmic reticulum stress (ERS), which collectively activate key inflammatory pathways (NF-κB, NLRP3, cGAS-STING). The resulting inflammatory milieu triggers apoptosis via death receptor and mitochondrial pathways, while apoptotic cells release damage-associated molecular patterns (DAMPs) that further amplify inflammation. Concurrently, fibrogenic signaling (TGF-β1/Smad, Hippo-YAP/TAZ) promotes epithelial–mesenchymal transition (EMT) and extracellular matrix (ECM) deposition. Crucially, the resulting fibrotic microenvironment reciprocally exacerbates inflammation and apoptosis through mechanical stress and hypoxia. Quantitative data from preclinical and clinical studies are integrated to underscore the magnitude of these effects. Current therapeutic strategies are evolving toward multi-target interventions against this pathological network. We contrast the paradigm of monotargeted agents (e.g., Finerenone, SGLT2 inhibitors), which offer high specificity, with that of multi-targeted natural product-based formulations (e.g., Huangkui capsule, Astragaloside IV), which provide synergistic multi-pathway modulation. Emerging approaches (metabolic reprogramming, epigenetic regulation, mechanobiological signaling) hold promise for reversing fibrosis. Future directions include leveraging single-cell technologies to decipher PTEC heterogeneity and developing kidney-targeted drug delivery systems. We conclude that disrupting the inflammation–apoptosis–fibrosis vicious cycle in PTECs is central to developing next-generation therapies for DN. Full article

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are forms of primary large vessel vasculitis (LVV) affecting the aorta and its major branches. Timely diagnosis and accurate monitoring are essential to prevent irreversible damage. Current assessment strategies rely heavily on symptoms, physical examination, and inflammatory markers, which lack sensitivity and specificity, particularly in patients treated with IL-6 inhibitors. This narrative review provides a comprehensive overview of the role of imaging in monitoring LVV. Ultrasound, magnetic resonance imaging, and positron emission tomography better reflect disease activity and treatment response compared to conventional clinical and laboratory measures. Notably, emerging imaging-based tools such as the OMERACT GCA Ultrasound Score, the Takayasu Ultrasound Index, and the TAK Integrated Disease Activity Index (TAIDAI) are promising treat-to-target instruments. While computed tomography is primarily used to assess structural damage, conventional angiography now plays a more limited role, mainly reserved for procedural planning and haemodynamic evaluation. A key challenge remains: interpreting persistent vascular abnormalities, which may indicate active disease, vascular remodelling, or irreversible damage. Standardisation of imaging protocols and interpretation is needed, alongside further research on the prognostic value of imaging for relapse risk. This review supports a multimodal, patient-tailored approach in which imaging is central to the long-term management of LVV. Full article

Concrete slabs in composite bridges are inevitably subjected to heavy vehicular loads during their service life. To evaluate the fatigue performance of the prestressed concrete slabs in composite bridges, two full-scaled models of prestressed concrete slabs were first designed and tested, with the load amplitude was selected as the variable. To simulate the damage caused by the initial passage of heavy vehicles, this was simplified into the form of a static cyclic load. The mechanical deformation state and crack distribution of the slab were analyzed. Further, a finite-element model was established, and a parametric analysis based on the variation in loading form, such as monotonic displacement loading, static cyclic loading followed by monotonic displacement loading, and cyclic displacement loading, was conducted to discuss the performance-enhancement mechanism of prestressed concrete slabs. Finally, in consideration of the influence of static cyclic damage on the fatigue performance of prestressed concrete slabs, evaluation parameters were proposed to account for static cyclic damage by considering the effects of stresses in concrete, tensile rebar, prestressed tendons, and external loading. A comprehensive fatigue performance evaluation method for prestressed concrete slabs, which neglects the tensile hardening behavior of cracked concrete in the tension zone, was established and verified by test results. The results indicate that the damage caused by static cyclic loading has a significant influence on the fatigue performance of the slab. Applying prestress can significantly mitigate the influence of initial damage on the mechanical and deformation behavior of the slab, which benefits from the prestress compensating for the cracking stress at the bottom of the slab. The proposed fatigue performance-evaluation method for prestressed concrete slabs, which considers static cyclic damage, can predict fatigue deformation behavior with an error of less than 10%, while reasonably determining the fatigue life and failure modes of prestressed concrete slabs. The parametric analysis reveals that when the prestress value exceeds 9 MPa, the failure mode of the prestressed concrete slab transfers from rebar fracture to concrete failure. Full article

The majority of Aeromonas strains are opportunistic pathogens for both humans and animals, causing a variety of diseases and posing a considerable risk to their health. In the current study, triploid cyprinid fish (TCF) were infected with a novel pathogenic Aeromonas sp. AS1-4 for pathological analysis. TCFs receiving Aeromonas sp. AS1-4 challenge exhibited oxidative damage in the liver and spleen, along with significant changes in immune-related gene expressions. Metabolomics assay indicated that strain AS1-4 challenge may exhibit a significant impact on metabolic processes of amino acids, with methylsuccinic acid (MSA) identified as vital biomarker. Following that, three potential probiotics designated Enterobacter strains fkY27-2, fkY84-1 and fkY84-4 were isolated from the intestine of TCFs, displaying excellent safety characteristics. In addition, intestinal Enterobacter strains exhibited multiple probiotic traits, including high degrees of hydrophobic activity, aggregation performance, biofilm-forming activity (BFA) and nutrient decomposing ability. Moreover, these probiotic isolates markedly coaggregated with Aeromonas sp. AS1-4 and Edwardsiella tarda 1l-4 and then suppressed their pathogenic biofilm-forming abilities, along with possessing robust antioxidant potential against various free radicals. These findings may provide valuable insights into metabolic response in fish post infection and health management in aquaculture. Full article

Background/Objective: Riboflavin transporter deficiency (RTD) is a rare neurodegenerative disease, with under 500 cases genetically confirmed since the early 2000s. Thus far, three separate subtypes of RTD2 are described—type 1, 2 and 3—but, previously, RTD was classified as two separate genetic defects: Brown–Vialetto–Van Laere syndrome and Fazio–Londe syndrome, caused by mutations in the SLC52A2 and SLC52A3 genes, respectively. The most prominent symptoms found in patients include encephalopathy, expressed as peripheral and cranial nerve neuropathy, which in turn lead to a series of complications: decreased muscle strength, hypotonia, visual impairment, sensorineural hearing loss, bulbar palsy, sensory ataxia and respiratory insufficiency secondary to diaphragmatic paresis. At the cellular level, riboflavin is modified into active flavin cofactors: FMN, mediating riboflavin phosphorylation through riboflavin kinase, and FAD, involved in FMN adenylation through the flavin dinucleotide 1 synthesis. FMN and FAD are two of approximately 100 proteins collectively described as the ‘flavoproteome’. Most of them are mitochondrial oxidoreductases, catalyzing the electron transport in many metabolic reactions, as well as regulating important cell processes, such as the production of reactive oxygen species, protein conformation and damage repair. FMN and FAD are also responsible for the conversion of B6 and B9 vitamins into their active forms, which allows for healthy cell growth and immune function. Methods: In this article, the authors describe two children, a 6-year-old girl and her 5-year-old sister, both presenting with RTD2 caused by mutations in the SLC52A2 gene (c.916G>C (p.Gly306Arg); c.477C>G (p.Cys159Trp)), in whom the disease progression was successfully inhibited by vitamin B₂ supplementation in varying doses. Results: Their clinical image consists of psychomotor developmental delay, ataxia, horizontal nystagmus, hearing loss and a lack of visual fixation. Conclusions: The phenotype and clinical signs presented by the described sisters are further discussed in relation to the previously published reports of RTD2 cases. Full article

The effect of the chemical composition of two low-carbon steels, C18E and 22MnB5, on their behavior after forming by fine blanking was investigated. A specific tool, adaptable to a tensile testing machine, was designed to replicate an industrial half-cutting process. This tool allows for the production of samples with simple geometries and easy modification of the processing conditions. Residual elements in the raw material, concentrated in segregation bands, appear to play a key role in crack initiation within the shear zone during the blanking process. The role of non-metallic inclusions is discussed to explain the presence of large cracks in C18E, while 22MnB5 only shows damage nucleation. After fine blanking, a carbonitriding heat treatment process was performed to modify the initial microstructure and achieve the required mechanical properties in the final parts. Continuous cooling transformation diagrams were created for both steels to guide this process. The results of this study demonstrate the better formability of 22MnB5 by fine blanking, compared to that of C18E. Full article

Steatotic liver disease (SLD) has become one of the most prevalent chronic liver diseases, representing a significant health burden worldwide. The complex pathogenesis of SLD results in a lack of specific therapeutic targets and effective drug treatment modalities. Copper (Cu) is a trace element that plays a critical role in various physiological processes, particularly hepatic metabolism. Meanwhile, Cu overload can induce cellular toxicity, which is generally explained by its capacity to induce oxidative damage. In 2022, a novel form of programmed cell death, designated as cuproptosis, was identified. In essence, excess Cu ions bind to the lipoylated components of the tricarboxylic acid cycle, resulting in proteotoxic stress and subsequent cell death. The role of cuproptosis in the pathologies of Cu overload-induced diseases has gained considerable attention. However, the association between SLD and Cu overload, particularly cuproptosis, remains to be elucidated. This review provides a concise overview of cuproptosis. The significance of Cu overload in SLD, as well as the potential association between cuproptosis and SLD, is explored. This review aims to offer insights into the potential of cuproptosis as a therapeutic target for SLD. Full article

Tunnel engineering is frequently undertaken in complex geological environments, which present heightened risks during construction and operation, particularly in active fault zones. This necessitates the enhancement of fault resistance. This study investigates the combined application of Steel–polypropylene Fiber Concrete Linings and Combined Seismic Joints through numerical simulation using ABAQUS 2023 (Dassault Systèmes, France). The findings demonstrate that this combination significantly enhances the fault resistance of tunnel structures, exhibiting substantial synergistic effects. In comparison with the utilization of Steel–polypropylene Fiber Concrete Linings as a standalone measure, the maximum reductions in longitudinal tensile and compressive strain were found to be 40.1% and 46.7%, respectively. Furthermore, peak equivalent compressive and tensile plastic strains were reduced by 60.3% and 51.1%, and tensile and compressive damage by 4.9% and 17.3%. Further analysis reveals that the steel fiber aspect ratio and the content of both steel and polypropylene fibers have varying effects on suppressing different damage forms in tunnel linings. It is evident that an augmentation in the steel fiber aspect ratio most effectively suppresses plastic zone deformation, while an increase in polypropylene fiber content significantly reduces tensile strain and tensile damage. The optimal level of fault resistance performance is achieved when the steel fiber content is set at 1.90%, the aspect ratio is 60, and the polypropylene fiber content is 0.15%. Furthermore, the adjustment of the combined arrangement parameters enables tunnel structures to adapt more effectively to diverse operational conditions, thus providing flexible design solutions for practical engineering applications. Full article