Adhesive Stress Research Articles

Three-dimensional finite element analysis of occlusal stress on maxillary first molars with different marginal morphologies restored with occlusal veneers

BackgroundThere are differences in the research results regarding which edge design of occlusal veneers can achieve the best long-term success rate as a relatively new fixed prosthesis restoration method. Further research is needed. The three-dimensional finite element method was used to conduct stress analysis on occlusal veneers of maxillary first permanent molars with different thicknesses and margin preparation designs. The aim of this study was to provide mechanical research evidence and a reference for exploring standardized clinical protocols for the design of occlusal veneer restorations of maxillary first molars.MethodA 3Shape (Intraoral Scanner) was used to scan the maxillary first molar teeth in vitro, after which 3D printing was carried out. Three different edge designs were applied to identical teeth: straight-beveled finishing line(SFL), chamfer finishing line(CFL), and standard cuspal inclination(SCI). Preparation was carried out with a thickness of 0.5 mm. Using the surface deformation feature, the occlusal veneer was thickened to 0.5 mm and 1.0 mm, and periodontal ligaments were added. They were then placed into the upper and lower jaws and dental arches. Finite element analysis was performed after applying bite force dispersion to the loading area on the mandible following dynamic contact.Results(1) As the thickness increased, the maximum Von Mises stress in the occlusal veneers SFL and CFL also increased, while the SCI exhibited the opposite trend. (2). The trend of the maximum Von Mises stress in the adhesive layer decrease gradually with increasing thickness of the occlusal veneer. The stresses of the SFL and CFL is concentrated primarily at the edge position below the functional cusp, resulting in relatively low adhesive stress. However, in the SCI group, the maximum stress at the edge of the adhesive layer exceeds the maximum shear strength of commonly used adhesives.ConclusionsUnder the experimental conditions, the mechanical properties of the maximum Von Mises stress in the SFL, CFL, and SCI occlusal veneers meet clinical needs. Incorporating the minimally invasive concept of tooth preservation, a thickness of 1.0 mm are optimal for glass ceramic occlusal veneers on maxillary first molars.

Adhesive paperboard connections in architectural applications: modelling, characterization, and performance assessment

ABSTRACT Paper-based elements have been researched as cheap and pro-ecological building materials for several decades and bonding is the most widely used method of joining them. However, adhesives may increase the cost, weight, and environmental impact of the component. The suitability of different adhesive types for paper-based building component bonding has not yet been researched. This work evaluates the properties of six types of commercially available adhesives – polyvinyl acetate, dextrin, and synthetic rubber. The results of single-lap tensile tests served as the input for a Goland–Reissner model of adhesive stresses. The elastic properties of the adhesives were estimated based on tensile test results – Shear modulus ranging from 0.626 to 1.097 MPa and Young’s modulus from 0.703 to 2.940 MPa. The modelled shear strength ranged from 1.1922 to 1.6115 MPa and the peel strength from 0.3265 to 0.5894 MPa. Recommendations for adhesive use in paper-based building elements are formulated. Polyvinyl acetate adhesives may be recommended for general use; however, the use of starch/dextrin adhesives should not be neglected. The presented work successfully demonstrates a methodology to obtain properties of adhesives for the mechanical assessment of the bonds from simple tensile tests of single-lap joints.

Research on adhesion properties of tidal flat soil on metal surface and discrete element simulation

The adhesion property of soil on the metal surface was tested by the orthogonal experiment with 4 factors and 3 levels based on piston pull out method. A regression model of adhesion stress and the factors including moisture content(X1), pressing time(X2), settling time(X3) and separation velocity (X4) was established. The experiment results show that the influence of each factor on adhesion stress is ranked as X1≈X2≈X3>X4>X3X4, and the adhesion stress shows an ‘S’ curve with the increase of separation velocity. The DEM parameters of the soil were calibrated based on the test results, and the contact and disturbance state of soil particles during the test were studied by discrete element method (DEM) using JKR model. The simulation tests show that the maximum adhesion stress occurs when the particles are about to separate from the probe surface, and the soil disturbance state is hierarchical.

Density Functional Theory Study of Adhesion Mechanism between Epoxy Resins Cured with 4,4'-Diaminodiphenyl Sulfone and 4,4'-Diaminodiphenylmethane and Carboxyl Functionalized Carbon Fiber.

The molecular mechanism of adhesion of two epoxy resins based on diglycidylether of bisphenol A (DGEBA) cured with 4,4'-diaminodiphenyl sulfone (DDS) and 4,4'-diaminodiphenylmethane (DDM) to the carbon fiber (CF) surface is investigated by employing density functional theory (DFT) calculations. The CF surface was modeled by the armchair-edge structure of graphite functionalized with carboxyl (COOH) groups. Two adhesion interfaces were constructed using the CF surface: one with the DGEBA-DDS molecule (CF/DGEBA-DDS interface) and the other with the DGEBA-DDM molecule (CF/DGEBA-DDM interface). The interfacial properties were analyzed by calculating the maximum adhesion stress (Smax) at the interface. The adhesion stress-displacement curve revealed that Smax is 1160.37 MPa, higher for the CF/DGEBA-DDS interface compared to the CF/DGEBA-DDM interface, which is 1060.48 MPa. The energy decomposition analysis showed a similar DFT contribution to adhesion stress for both interfaces, but the dispersion contribution is more significant at the CF/DGEBA-DDS interface. The crystal orbital Hamilton population (COHP) analysis revealed distinct interfacial interactions despite similar DFT contributions. Hydrogen bonding (H-bonding) between the functional groups at both interfaces including feeble OH-π interactions between the benzene rings of epoxy resins and COOH groups on the CF surface were observed. The orbital interaction energies calculated from integrated COHP, i.e., IpCOHP, revealed that the CF/DGEBA-DDS interface has six H-bonding interactions with large absolute IpCOHP values (>1 eV), whereas the CF/DGEBA-DDM interface has five. The interaction between the amine group of the DGEBA-DDM molecule and the CF surface has a large IpCOHP value among all interactions. The sulfone group being at the center of the DDS molecule and its strong surface interaction positioned the DGEBA-DDS molecule closer to the CF surface than the DGEBA-DDM molecule, enhancing dispersion interaction at the CF/DGEBA-DDS interface. Hence, the CF surface exhibits a stronger affinity toward the DGEBA-DDS molecule than the DGEBA-DDM molecule through dispersion interaction.

Effect of repair patch nature on J-integral reduction in notched plates

PurposeThe purpose of this research is to evaluate the effectiveness of different repair patch materials in reducing the stresses at the crack tip of a 2024-T3 aluminum plate. This involves a numerical analysis using the finite element method (FEM) to estimate the reduction in the J-integral value, with the goal of identifying how various parameters related to the patch materials, adhesive properties and loading conditions influence the structural integrity of the repaired plate.Design/methodology/approachThe methodology of this research involves conducting a numerical analysis using the FEM to estimate the reduction in the J-integral value at the crack tip of a 2024-T3 aluminum plate. Three types of patches – metal, composite and functionally graded material (FGM) – were examined under tensile loading conditions, and Adekit-A140 adhesive was used to bond these repair patches to the aluminum plate.FindingsThe analysis considered various parameters, including crack length, the nature of fibers in the composite material, the gradation exponent for FGM patches and the nature of the face in contact with the adhesive for the FGM patch. Additionally, stress analysis was conducted, examining the J-integral values for the plate, shear stress in the adhesive layer and peel stress in the composite patch. The findings highlight that modifying the nature of the repair patch used can significantly enhance the structural integrity of the repaired plate.Originality/valueThe study analyzed J-integral values, shear stress in the adhesive and peel stress in the composite patch. Various parameters, including crack length, fiber type, gradation exponent and adhesive contact face nature, were considered. Results demonstrate that the J-integral value can be significantly reduced by altering the repair patch type, highlighting the effectiveness of customized patch materials in enhancing structural integrity.

Stress granule formation enables anchorage-independence survival in cancer cells.

Either anoikis stress or loss of adhesion induce stress granule (SG) formationThe Rho-ROCK-PERK-eIF2α axis is a crucial signaling pathway triggered by the absence of adhesion signals, leading to the promotion of SG formation along with the inhibition of the FAK- AKT/mTOR-eIF4F complex under anoikis stress.PERK functions as an oncogene in breast cancer cells, initiating SG formation and activating AKT under anoikis stress.Inhibiting SG formation significantly enhances the sensitivity to Focal Adhesion Kinase (FAK) inhibitors, suggesting a potential for combined therapy to improve cancer treatment efficacy.

IFIT2 mediates iron retention and cholesterol efflux in atherosclerosis

BackgroundAbnormalities in iron and lipid metabolism are recognized as key contributors to atherosclerosis (AS). Therefore, this study proposes to characterize the biomarker related to iron and lipid metabolism in AS using bioinformatics, animal, and cell experiments. MethodsThe limma package was utilized to identify differentially expressed genes (DEGs) in GSE70126 and GSE70619 datasets, and biomarkers were screened using enrichment analysis and PPI networks. IFIT2 was knocked down using shRNA lentivirus in a high fat diet (HFD)-induced APOE-/- AS model to investigate its effects of IFIT2 on the pathology, iron retention, and lipid accumulation. Iron storage-related and cholesterol efflux-related proteins were evaluated following exogenous modulation of IFIT2 expression in ox-LDL-induced foamy macrophages. ResultsCompared to non-foamy macrophages from the aorta, 189 and 4152 DEGs were identified in foamy macrophages within the GSE70126 and GSE70619 datasets, respectively. Moreover, intersecting DEGs may modulate immune responses, cell adhesion, vascular permeability, and oxidative stress through NF-kappa B, Wnt, TNF and HIF-1 signaling pathways. Notably, IFIT2 was significantly upregulated in foamy macrophages and AS models. In vivo, IFIT2 co-localized with foamy macrophages, and its knockdown led to reductions in plasma lipid levels, plaque area, immune infiltration, iron retention, and lipid accumulation. In vitro, IFIT2 knockdown alleviated the ox-LDL-induced increase in iron storage-related proteins (Ferritin-L and Ferritin-H) and iron (Fe2+ and Fe3+) in foamy macrophages. Furthermore, IFIT2 knockdown reduced lipid accumulation and upregulated cholesterol efflux-related proteins (PPARγ, LXRα, ABCA1, and ABCG1) in foamy macrophages. ConclusionIFIT2 knockdown attenuates iron retention and lipid accumulation in AS plaques, and facilitated cholesterol efflux from foamy macrophages via the PPARγ/LXRα/ABCA1-ABCG1 pathway.

Liquid-infused surface on optimized anodic porous aluminum for anti-frost and anti-ice application

Here, we present liquid-infused surfaces (LISs) fabricated on an aluminum substrate using the anodizing method to introduce specific nanofeatures infiltrated by silicone oil to reduce the friction between ice and surface. To achieve various nanostructures on the aluminum substrate, the anodizing conditions are varied. The ice adhesion stress could be significantly plummeted to 21.7 kPa on an LIS with optimized dimensions for nanofeatures. Frost formation tests in environments with a relative humidity of 75 % on the fabricated surfaces with a temperature of −17 ℃ reveal that the fabricated samples can considerably extend the frost formation time. The frosting time for the fabricated sample can reach 47 min, whereas the bare aluminum is completely covered by frost only after 1.5 min

Experimental study of bond-slip relationships in high-performance self-consolidating concrete with plain steel bars

Self-consolidating concrete is being used more frequently in structures with high density of reinforcement bars or prestressing strands therefore, it is important to carefully consider whether bond stress-slip relations defined for normal strength concrete can be safely applied to high-strength and self-consolidating concrete. This paper aims to investigate the bond behaviour between plain steel bars and high-performance self-consolidating concrete, with a focus on studying the effect of embedment length and concrete compressive strength on bonding performance. The main parameters that were tested are the active bonded length and the compressive strength of the concrete. The value of adhesive bond stress is discussed, as a factor in determining whether the bar slips against the adhering concrete. Based on the results, it can be observed that the maximum bond stress tends to increase with higher concrete compressive strength, while it decreases with longer embedment length of plain steel bar. Conversely, the adhesive bond tends to increase with longer embedment length and higher concrete compressive strength. The experimental investigations indicate that the bond strength increases proportionally to the square root of the compressive strength of concrete, regardless of the concrete compressive strength. Furthermore, a new bond stress-slip model has been analyzed, which takes into account the initial bond strength (adhesive bond) and the lower convex property to predict the post-peak branch. The model has been compared to the test results, and good agreement has been achieved.

Pemphigus vulgaris autoantibodies induce an ER stress response.

Desmosomes are intercellular junctions that mediate cell-cell adhesion and are essential for maintaining tissue integrity. Pemphigus vulgaris (PV) is an autoimmune epidermal blistering disease caused by autoantibodies (IgG) targeting desmoglein 3 (Dsg3), a desmosomal cadherin. PV autoantibodies cause desmosome disassembly and loss of cell-cell adhesion, but the molecular signaling pathways that regulate these processes are not fully understood. Using high-resolution time-lapse imaging of live keratinocytes, we found that ER tubules make frequent and persistent contacts with internalizing Dsg3 puncta in keratinocytes treated with PV patient IgG. Biochemical experiments demonstrated that PV IgG activated ER stress signaling pathways, including both IRE1⍺ and PERK pathways, in cultured keratinocytes. Further, ER stress transcripts were upregulated in PV patient skin. Pharmacological inhibition of ER stress protected against PV IgG-induced desmosome disruption and loss of keratinocyte cell-cell adhesion, suggesting that ER stress may be an important pathomechanism and therapeutically targetable pathway for PV treatment. These data support a model in which desmosome adhesion is integrated with ER function to serve as a cell adhesion stress sensor that is activated in blistering skin disease.

Capillary adhesion of stick insects.

Scientific progress within the last few decades has revealed the functional morphology of an insect's sticky footpads-a compliant pad that secretes thin liquid films. However, the physico-chemical mechanisms underlying their adhesion remain elusive. Here, we explore these underlying mechanisms by simultaneously measuring adhesive force and contact geometry of the adhesive footpads of live, tethered Indian stick insects, Carausius morosus, spanning more than two orders of magnitude in body mass. We find that the adhesive force we measure is similar to the previous measurements that use a centrifuge. Our measurements afford us the opportunity to directly probe the adhesive stress in vivo and use existing theory on capillary adhesion to predict the surface tension of the secreted liquid and compare it to previous assumptions. From our predictions, we find that the surface tension required to generate the adhesive stresses we observed ranges between 0.68 and 12 mN . The low surface tension of the liquid would enhance the wetting of the stick insect's footpads and promote their ability to conform to various substrates. Our insights may inform the biomimetic design of capillary-based, reversible adhesives and motivate future studies on the physico-chemical properties of the secretedliquid.

Evaluation of side and tip resistances for barrette piles using CYCU/Barrette/Side&Tip/64

This study focuses on evaluating the side and tip resistances for barrette piles under compression loading. An extensive dataset from field load tests, designated as CYCU/Barrette/Side&Tip/64, was utilized for analysis. These data were categorized into drained and undrained soils, based on the predominant soil conditions along the pile shaft. In contrast, tip resistance depended on the soil (drained or undrained) or rock condition at the pile tip. Eight interpretation methods were employed to evaluate the measured side and tip resistances of each load test. The predicted side resistance was calculated using the classical α and β methods developed for more common piles such as drilled shafts. For the prediction of tip resistance, end-bearing capacity models for a drilled shaft resting on soil or socketed in rock are considered. Subsequently, a comparison was made between the measured and predicted capacities. Based on these analyses, it was observed that the measured side resistance is the main contributor to the overall capacity of barrette piles. The percentage of measured side resistance ranges from around 80% to 90%. In addition, the predicted side resistance calculated using the α and β methods is smaller than the measured side resistance interpreted using the L2 criterion. To reduce this prediction bias, the adhesion factor (α) and stress factors (K/Ko) for barrette piles were adjusted. For the tip resistance, the trend is opposite – predicted values are larger than the measured values for barrette piles resting on soil or socketed in rock. Another approach to correct for prediction bias called the generalized model factor is presented.

Effect of steel fibers and the fiber-concrete adhesion stress on the nonlinear shear behavior of beams

In this article, a theoretical model in nonlinear elasticity is presented to analyze the influence of the percentage of steel fibers and the effect of the fiber-concrete bond stress on the shear force at the rupture of beams subjected to the combined effect of bending moment, normal force, and shear force. For a given beam section, it is defined by a succession of layers of concrete and longitudinal steel elements. Each layer is defined by its height hi, width bi, and position relative to one end of the section YGi. Each longitudinal steel element is also defined by its cross-sectional area and position relative to one end of the section. The steel fibers are defined by volume percentages of 0.5%, 1%, 1.5%, and 2%, taking into account the mechanical nonlinearity of the materials. This model is based on the multilayer analysis of sections and an iterative solution procedure for each layer and each section, considering a given longitudinal deformation state and shear stress. The global equilibrium of the sections is analyzed under the assumption of flat longitudinal deformations but with, in principle, an interdependence of longitudinal normal stresses and shear stresses. In this study, using the principle of virtual work, equilibrium equations for deformations and stresses, as well as partial compatibility equations between concrete deformations and mean deformations, are derived. Comparative examples between ordinary reinforced concrete beams with variable shapes and reinforcement details, and those reinforced with steel fibers, are presented to demonstrate the accuracy of the proposed model for simulating the nonlinear shear response of beams.

Experimental, theoretical and numerical study on the shear stress of adhesive layer in FRP-bamboo scrimber composite beams

The adhesive layer is an important factor affecting the mechanical properties of FRP- bamboo scrimber composite beams (FBSCB). However, studies on the interfacial shear stresses in the adhesive layers with both ends of FRP and bamboo scrimber beam aligned have been rarely reported. To this end, a two-parameter theoretical calculation model and a finite element model (FEM) based on cohesive zone model were hereby established to solve for the adhesive layer interface shear stresses, which was verified by four-point bending experiments. The results show that both the two-parameter theoretical model and the FEM can effectively compute the shear stress of the adhesive layer. Meanwhile, the FEM simulation results not only reflect the detailed changes of the shear stress, but also provide a better analysis of the shear stress at the adhesive layer with a small fluctuation range. There are three zones of shear stress at the adhesive layer of FBSCB under four-point bending load, i.e., the bending and shearing zone, the transition zone and the pure bending zone. In the bending and shearing zone, the shear stress of the adhesive layer interface increases 2.61 times and 2.5 times, respectively when the thickness and elastic modulus of FRP increase three times. However, the stress remains constant at zero in the pure bending zone.

Probing local adhesion: A miniaturized multi-photon lithography design demonstrated on silanized vs. untreated surfaces

As multi-photon lithography technology matures, advanced integrated device design concepts become possible, positioned onto small surfaces, such as optical fibres. Only local adhesion anchors the printed object on the surface and ensure proper print-development without structure loss and long-term usability. Although surface treatments such as silanization are well known to considerably increase adhesion strength, quantification of adhesion is not straightforward and commonly assessed indirectly by surface characteristics and technological methods. The present work aims to quantify adhesion on a micrometer scale through SEM in situ tension experiments, that utilize a newly developed specimen geometry. Multiple specimens, with various footprints, were manufactured on both silanized and untreated fused silica substrates, allowing the comparable quantification of adhesion stresses between different surface conditions. Specimens on an untreated substrate failed with a high scatter in detaching force, whereas specimens on a silanized substrate tend to fail within the photoresist, either at the gauge section or just above the substrate, rather than at the interface itself. Thus, the adhesion stress was increased at least by a factor of 1.4 by the silanization treatment. Generally, a novel approach was developed, that can quantify local adhesions properties in realistic packaging or integrated circuits.

Soil conditioning of clay based on interface adhesion mechanism: Microscopic simulation and laboratory experiment

Clogging frequently occurs in the cutter head, excavation chamber or screw conveyor when an earth pressure balance (EPB) shield machine is tunneling in soft or silty clay ground with high clay mineral content. In this paper, montmorillonite, kaolinite, and illite were selected as research objects, and molecular dynamics simulation and laboratory experiment were adopted. At the microscopic scale, dynamic contact behavior and interfacial mechanical behavior of the interface between clay minerals and water/surfactant solution was simulated and the interfacial adhesion and conditioning mechanism between clay minerals and water/surfactant solution was revealed. Thus, sodium dodecyl benzene sulfonate surfactant was selected as the main composition of the soil conditioner. Then, the adhesion stress before and after soil conditioning and the contact angles between clay minerals and water/surfactant solution were tested and analyzed at the macroscopic scale. The result shows that the contact angle between droplet and clay mineral surface is an important parameter to characterize soil adhesion. The simulation rules of the microscopic contact angle are consistent with the experiment results. Furthermore, the adsorption energy between microscopic substances is dominated by electrostatic force, which can reflect the adhesion stress between macroscopic substances. Soil adhesion stress can be effectively decreased by adding the surfactant to the soil conditioner.

Synergistic enhancement of hydrophobic dental adhesives: autonomous strengthening, polymerization kinetics, and hydrolytic resistance

The leading cause of composite restoration failure is recurrent marginal decay. The margin between the composite and tooth is initially sealed by a low-viscosity adhesive, but chemical, physical, and mechanical stresses work synergistically and simultaneously to degrade the adhesive, destroying the interfacial seal and providing an ideal environment for bacteria to proliferate. Our group has been developing self-strengthening adhesives with improved chemical and mechanical characteristics. This paper reports a self-strengthening adhesive formulation that resists hydrolysis-mediated degradation by providing intrinsic reinforcement of the polymer network through synergistic stimulation of free-radical polymerization, sol-gel reaction, and hydrophobicity. Hydrophobic resin formulation (NE1) was developed using HEMA/BisGMA 28/55w/w and 15 wt% MPS. Control (NC1) contained HEMA/BisGMA 28/55 w/w and 15 wt% MES. The polymerization kinetics, water sorption, leachates, and dynamic mechanical properties of the resin samples were investigated. The NC1 and NE1 samples showed comparable polymerization kinetics, degrees of conversion and water sorption. In contrast, NC1 showed significantly higher levels of HEMA and BisGMA leachate, indicating faster degradation in ethanol. At day 3, cumulative HEMA leachate for NC1 was ten times greater than NE1 (p < 0.05). Dynamic mechanical properties were measured at 37 and 70°C in both dry and wet conditions. Under dry conditions, the storage moduli of NC1 and NE1 were comparable and the glass transition temperature (Tg) of NC1 was statistically significantly lower (p < 0.001) than NE1. Under wet conditions, the storage modulus of NC1 was lower than NE1 and at 70°C there was a threefold difference in storage modulus. At this temperature and under wet conditions, the storage modulus of NC1 is statistically significantly lower (p < 0.001) than NE1. The results indicated that in the wet environment, NE1 provided lower chain mobility, higher crosslink density, and more hydrogen bonds. The newly formulated methacrylate-based adhesive capitalizes on free-radical polymerization, sol-gel reactions, and hydrophobicity to provide enhanced mechanical properties at elevated temperatures in wet environments and hydrolytic stability under aggressive aging conditions.

Curtailing the Ambient Air Ageing Effect on Mechanical Properties of Vacuum Evaporated Al2O3 Thin Films Using Vapor Chopping Technique

Here, we studied the 30-day ambient air exposed vacuum evaporated Al2O3 thin films. The ageing effect on mechanical properties like intrinsic stress as well as adhesion was studied. Vapor chopping technique (VCT) was used during deposition. To find ageing effect in vapor chopped (VC) and as deposited i.e. nonchopped (NC) Al2O3 thin films comparative study was done. VC and NC Al2O3 thin films’ X-ray diffraction (XRD) patterns remain the same even after 30 days ageing, i.e., no structural variation was found due to ageing. Adhesion degradation was observed in deposited films i.e. NC films showed reduction from 266±5×103 to 189±5×103 N/m2 whereas VC thin films showed 355±5×103 to 332±5×103 N/m2. Intrinsic stress increased from 41±2×107 to 61±2×107 N/m2 in NC and 31±2×107 to 39±2×107 N/m2 in VC Al2O3 thin films. Even though, overall VC films showed higher adhesion and smaller intrinsic stress than NC Al2O3 thin films i.e., curtailing ambient air ageing effect in VC thin films was perceptible.

Effect of Adhesive Type on the Adhesively Bonded Stepped Joint: A Numerical Investigation

Single-lap joints are by far the most widely used adhesive joints and have been the subject of considerable research over the years. It is used in the automobile and aerospace industry where bolted or riveted joints are impossible. The joint strength in adhesively bonded joints depends on the adhesive and adherend properties and adherend geometry. In this paper, both the adhesive property and adherend geometry are considered. Two types of adhesives, i.e., SBT9244 (flexible) and DP460 (stiff), and three types of adherend geometry, Single Lap Joint (SLJ), One Step Lap Joint (OSLJ), and Three Step Lap Joint (TSLJ) are considered, and the effect of these are investigated by using a commercially available software Abaqus. The maximum peel stress occurs in a lap joint towards the edges of the joint and is minimum around the center region. The maximum peel stress is responsible for the failure of the joints, and the objective of this research was to reduce the peel stress, i.e., provide a more uniform stress distribution. Soft adhesive maximum peel stress and shear stress occur in [Type-I] 8.6 MPa and 6.4 MPa, respectively. Similarly, stiff adhesive maximum peel stress and shear stress occur in [Type-I] 37.14 MPa and 20.44 MPa, respectively. It is found from this investigation that if a relatively soft adhesive (SBT9244) is used in the joint, then the stress distribution reduces compared to a stiff adhesive (DP460). On the other hand, if steps are introduced in the bonded region, the stress distribution becomes more uniform and increases the bond strength.

Unveiling the Impact of Hemodynamics on Endothelial Inflammation-Mediated Hepatocellular Carcinoma Metastasis Using a Biomimetic Vascular Flow Model.

Hepatocellular carcinoma (HCC) hematogenous dissemination is a leading cause of HCC-related deaths. The inflammatory facilitates this process by promoting the adhesion and invasion of tumor cells in the circulatory system. But the contribution of hemodynamics to this process remains poorly understood due to the lack of a suitable vascular flow model for investigation. This study develops a vascular flow model to examine the impact of hemodynamics on endothelial inflammation-mediated HCC metastasis. This work finds the increasing shear stress will reduce the recruitment of HCC cells by disturbing adhesion forces between endothelium and HCC cells. However, this reduction will be restored by the inflammation. When applying high FSS (4-6dyn cm-2) to the inflammatory endothelium, there will be a 4.8-fold increase in HCC cell adhesions compared to normal condition. Nevertheless, the increase fold of cell adhesions is inapparent, around 1.5-fold, with low and medium FSS. This effect can be attributed to the FSS-induced upregulation of ICAM-1 and VCAM-1 of the inflammatory endothelium, which serve to strengthen cell binding forces. These findings indicate that hemodynamics plays a key role in HCC metastasis during endothelial inflammation by regulating the expression of adhesion-related factors.