Fiber Adhesion Research Articles

The Effect of Phosphoric Acid on the Flame Retardancy and Interfacial Adhesion of Carbon Fiber with Thermoplastic Resin PA6

This study investigated the effect of phosphoric acid treatment on carbon fibers to enhance their flame retardancy, the impact of carbon fiber surface treatment conditions on the interfacial adhesion between carbon fibers and PA6, and the chemical reaction mechanisms on the carbon fiber surface. Phosphoric acid treatment resulted in a flame-retardant effect, with a limited oxygen index of over 52.8%, and V0 level flame retardancy characteristics in the UL-94 test when the concentration exceeded 0.5 vol.%. When the treatment time was fixed at 30 min, the tensile strength increased by approximately 2%, and the interfacial shear strength (IFSS) increased by approximately 11% at 0.5 vol.% phosphoric acid, accompanied by an increase in hydroxyl (C–O), carbonyl (C=O), phosphate (P–O), and phosphoryl (P=O) groups. However, at concentrations higher than 0.5 vol.%, the tensile strength decreased by approximately 90%, and the IFSS decreased by approximately 12%, compared to the untreated nonwoven fabric. When the treatment time was varied at 0.5 vol.% phosphoric acid, both the tensile strength and IFSS increased continuously up to 10 min, with a 31% increase in tensile strength and a 17% increase in IFSS, along with an increase in O=C–O, P–O, and P=O groups, as well as surface energy. After 10 min, the tensile strength decreased by approximately 20%, while the IFSS and surface energy remained relatively unchanged.

Effect of Using Plant Fiber on The Properties of Concrete

With light weight, wide sources, low cost and renewable, plant fiber concrete has become the preferred green building materials. This paper reviews the research status of bamboo fiber, flax, hemp, jute, ramie and other high-strength plant fibers, and discusses their basic properties and defects, such as strength, interface bonding, thermal insulation, as well as fiber corrosion, adhesion, water absorption and workability. In view of these, the strategies of pretreatment, use of mineral admixtures, optimization of bonding materials and improvement of mixing process are put forward. The results show that reasonable improvement measures can significantly improve the performance of plant fiber concrete. This paper provides theoretical and technical support for the application of plant fiber concrete, and looks forward to its wide application prospect in the field of civil engineering.

Assessment of surface treatment methods for strengthening the interfacial adhesion in CARALL fiber metal laminates

Metal and polymer interface bonding significantly influences the mechanical performance of fiber metal laminates (FMLs). Therefore, the effect of surface treatments (mechanical abrasion, nitric acid etching, P2 etching, sulfuric acid anodizing (SAA), and electric discharge machine (EDM) texturing) carried on aluminum 2024-T3 alloy sheets was evaluated considering surface morphology, surface topography, and surface roughness. Further, the influence of surface treatments on interfacial adhesion strength and failure mode between the aluminum alloy and carbon fiber prepreg was investigated. The surface treatments increased the surface roughness of the aluminum substrates. Surfaces treated using SAA, nitric acid, and P2 etchant showed improved wettability, while mechanically abraded and EDM textured substrates showcased hydrophobic behavior. The selected surface treatments significantly affected interfacial adhesion between the epoxy polymer and aluminum alloy. SAA and EDM texturing greatly enhanced the interfacial peel strength of FMLs. In the case of interfacial shear strength, EDM textured substrate showed superior performance, followed by SAA. Moreover, untreated and mechanically abraded specimens exhibited weaker bonding and adhesive failure at the aluminum-epoxy interface, whilst chemical treatments resulted in mixed model failure. EDM textured surface underwent cohesive failure, while a dominant mixed mode failure and fiber adhesion were observed in the SAA-treated specimen.

Mechanical Properties of Concrete Mixes with Selectively Crushed Wind Turbine Blade: Comparison with Raw-Crushing.

The glass fiber-reinforced polymer (GFRP) materials of wind turbine blades can be recovered and recycled by crushing, thereby solving one of the most perplexing problems facing the wind energy sector. This process yields selectively crushed wind turbine blade (SCWTB), a novel waste that is almost exclusively composed of GFRP composite fibers that can be revalued in terms of their use as a raw material in concrete production. In this research, the fresh and mechanical performance of concrete made with 1.5%, 3.0%, 4.5%, and 6.0% SCWTB is studied. Once incorporated into concrete mixes, SCWTB waste slightly reduced slumps due to the large specific surface area of the fibers, and the stitching effect of the fibers on mechanical behavior was generally adequate, as scanning electron microscopy demonstrated good fiber adhesion within the cementitious matrix. Thus, despite the increase in the content of water and plasticizers when adding this waste to preserve workability, the compressive strength only decreased in the long term with the addition of 6.0% SCWTB, a value of 45 MPa always being reached at 28 days; Poisson's coefficient remained constant from 3.0% SCWTB; splitting tensile strength was maintained at around 4.7 MPa up to additions of 3.0% SCWTB; and the flexural strength of mixes containing 6.0% and 1.5% SCWTB was statistically equal, with a value near 6.1 MPa. Furthermore, all mechanical properties of the concrete except for flexural strength were improved with additions of SCWTB compared to raw crushed wind turbine blade, which apart from GFRP composite fibers contains approximately spherical polymer and balsa wood particles. Flexural strength was conditioned by the proportion of fibers, their dimensions, and their strength, which were almost identical for both waste types. SCWTB would be preferable for applications in which compression stresses predominate.

Mechanical, machinability and water absorption properties of novel kenaf fiber, glass fiber and graphene composites reinforced with epoxy

This paper aims to fabricate a novel kenaf fiber, glass fiber, graphene composite reinforced with epoxy, and to study its water absorption, mechanical and machining properties. Natural fiber composites seek numerous applications nowadays due to its high strength is to weight ratio, high impact resistance, thermal stability, and recyclability. The literature study on natural fiber composites indicates lack of research on Kenaf fibers reinforced with E-glass fibers in conjunction with 0.5% and 1.0% of graphene. Hence, this research focuses on Kenaf fiber with percentage composition of graphene was varied as 0.5%, and 1.0%, by weight of the holding matrix and with/without incorporation of glass fiber. Suitable surface modifications were done by treating natural fibres by 0.5% NaOH for better adhesion of fibre and epoxy resin. Sonication and Cetyl trimethyl ammonium bromide (CTAB) treatments were also done to realize the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were prepared as per D-638 ASTM standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. The main objectives of this study are to conduct tensile, flexural, Impact, water absorption, machinability, and FTIR test. Result shows that the incorporation of graphene in natural fiber composites showed an increase in tensile strength, flexural strength, and water absorption properties by 27.7%, 53%, and 15% on average, respectively. The composites used in this research find their use in potential applications such as defence, biomedical aids, automobiles, packaging, actuators, etc. These often generate great interest, whenever there is a demand for fabricating lightweight and high strength material.

Effects of plasma modification of hybrid Kevlar/PTFE fabric surface on adhesive and tribological properties

A study on surface modification with Ar and N2 plasma of hybrid PTFE/Kevlar fabrics was conducted. The chemical and molecular structure changes of the PTFE and Kevlar fibers were analyzed as well as their surface properties i.e. roughness, morphology, wettability, and surface energy. The results show that the treatment caused etching and defluorination on the PTFE fiber surface improving its hydrophilicity, surface energy, and adhesion of the Kevlar fiber without weakening its mechanical strength. The plasma treatment contributed to improving the interfacial strength of the composite, enhancing its adhesion to the metal substrate. The long-term friction and wear behaviors were also investigated to obtain a better understanding of the tribological properties of the hybrid Kevlar/PTFE-epoxy/phenolic composites. The results illustrate that the treated fabric composite showed better wear resistance and self-lubrication performance due to the improved wettability and adhesive properties of the fabrics. The modification effect of the sample treated with Ar plasma is better; however, N2 is economical, and the effect is also significant.

Hyperbranched bio-based waterborne sizing coating for enhancing the wettability of carbon fibre and interfacial adhesion of fibre/epoxy composites

Novel castor oil-based waterborne polyurethane (CWPU) sizing coatings prepared by replacing traditional petroleum-based petrochemical products with natural renewable bio-extracts are attracting the attentions in the carbon fibre (CF) reinforced epoxy (EP) composites industries. However, CWPU coatings prepared using only castor oil (CO), diisocyanate, and carboxylate hydrophilic chain extender suffer from poor thermal stability, insufficient mechanical strength and weak adhesion. For enhancing the thermo-mechanical properties of CWPU coatings, as well as the surface wettability and interfacial adhesion to the substrates when serving as fibre sizing coatings and as interphases of the CF/EP composites, a compound cross-linker with tri-acrylate branched and tri-isocyanate chain-endings was synthesized and used to prepare hyperbranched CWPU with CO-acrylate-isocyanate interpenetrating cross-linking networks. CWPU coatings revealed favourable thermodynamic performance achieving a T5% decomposition temperature and toughness of 271.8 °C and 36.2 MJ/m3. CWPU coatings imparted excellent wettability to CF through oxygen-containing polar groups and synergy between covalent/hydrogen bonding, resulting in an increase in fibre surface energy to 61.0 mN/m. Stable and robust interphases were constructed in the CF/EP composites by CWPU coatings through "polar similarity compatibility" and multiple physico-chemical reactions. The flexural modulus, interlaminar shear strength, and interfacial shear strength of CWPU-CF/EP were increased by 54.8 %, 36.6 %, and 58.9 %, respectively, compared with those of the unsized CF/EP composites. The research contributes to the development and industrial production of high-performance, eco-friendly bio-based water soluble organic coatings.

Thermo‐mechanical performance of oil palm/bamboo fiber reinforced bio epoxy hybrid composites

AbstractThe aim of this work to fabricate bamboo (B)/oil palm (O) fibers based biocomposites to assess mechanical, thermal and morphological properties. Flexural strength and modulus of hybrid biocomposite (7B:3O) exhibited a higher value (71.18 MPa and 5.24GPa) respectively among all biocomposite samples. On the other hand, pure biocomposite (B) showed a higher impact strength value (6977.8 J/m2) compared to other biocomposites. The results of TGA showed that thermal stability was observed significantly for hybrid biocomposites compared to other samples. In addition, the maximum decomposition temperature values were displayed in the hybrid biocomposite (5B5O), which was 377.82°C. Through DMA, it was likely to find the storage modulus curves (E′), loss modulus (E″) and damping factor (tan δ) for the biocomposites. The E′ showed an increase in the (3736.84 MPa) contrasted to other corresponding samples which were 3121.81 MPa, and 3209.67 MPa for 3B7O MPa and 5B5O samples, respectively. Overall, the results of DMA displayed an enhancement in the storage modulus (E′) in terms of the hybrid biocomposites representing greater stiffness and lower damping factor. SEM micrographs were utilized to understand the fiber bonding and fiber adhesion with the epoxy matrix. Furthermore, it confirmed SEM results that hybrid natural fibers enhance the complete characterisations of bio‐epoxy materials. Additionally, SEM images of the tensile fracture surfaces discovered voids and cracks. Finally, it can be concluded that the selection for the developed hybrid biocomposites provides excellent and economical lightweight biomaterials for automotive, aerospace, contractions and building components.Highlights Green hybrid biocomposites by oil palm/bamboo fiber/bioepoxy resin. Mechanical, thermal, DMA of hybrid composites carried out. Hybrid biocomposite(7B:3O) exhibited higher flexural strength value (71.18 MPa). TGA showed that the biocomposites are thermally further stable. DMA displayed an enhancement in the storage modulus (E′).

Enhancing the Interfacial Property Between UHMWPE Fibers and Epoxy Through Polydopamine and SiO2 Surface Modification.

Here, a combination of dopamine self-polymerization and epoxy modified SiO2 (M-SiO2) grafting was proposed, with the purpose of increasing interfacial adhesion of UHMWPE fiber. Inspired by mussel adhesion, polydopamine (PDA) was deposited onto the surface of UHMWPE fiber to form a thin layer with amino and hydroxyl groups. M-SiO2 nanoparticles were then adhered to fiber surface via chemical reactions by a "two-step" or "one-step" technology. In the "two-step" technique, the M-SiO2 nanoparticles were adhered to the surface of PDA modified UHMWPE fiber via reactions between epoxy and amino groups. In the "one-step" method, M-SiO2 and dopamine were added into the UHMWPE/Tris solution at the same time. Surface morphology and thermal properties of various UHMWPE fibers were tested by SEM and TGA, respectively. Surface wettability of different UHMWPE fibers were evaluated by dynamic contact angle. The results proved that PDA and M-SiO2 were successfully adhered to the surface of UHMWPE fibers. The mechanical property of modified UHMWPE/Epoxy composites was investigated, and 43.7 % improvement was obtained, compared with unmodified UHMWPE/Epoxy composite. Additionally, micro-bond test revealed that the interfacial property (IFSS value) of modified UHMWPE fiber via the "one-step" method was 6.08 MPa, significantly higher than that of unmodified UHMWPE fiber (2.47 MPa).

The Evaluation of Sandwich Composite Materials with Vegetable Fibers in a Castor Oil Polyurethane Matrix with Their Faces and Honeycomb Core Made in a 3D Printer.

Sandwich panels are widely used in the naval and aerospace industries to withstand the normal tensile, compressive, and shear stresses associated with bending. The faces of sandwich composites are usually made of metals such as aluminum and, in some studies with composites, using a polymeric matrix, but there are no studies in the literature using a castor oil polyurethane matrix. The core of the panel must keep the faces apart and be rigid perpendicular to them. To begin the work, a study was carried out on the influence of alkaline treatment on sisal fibers to increase the fibers' adhesion to castor oil polyurethane. There are no relevant studies worldwide on the use of this resin and the adhesion of vegetable fibers to this polyurethane. In this work, a study was carried out through a three-point bending test of sandwich panels using faces of composite material with sisal fibers subjected to an alkaline treatment of 10% by weight of sodium hydroxide and an immersion time of 4 h in the dissolution, which was the best chemical treatment obtained initially in a castor oil polyurethane matrix. The honeycomb cores were made by 3D printer and in this study two different printing filament materials, PETG and PLA, and two different core heights were compared. As a result of a traction test, it was observed that sisal fibers with chemical treatment in a castor oil polyurethane matrix can be used in composites, although the stress levels obtained are 50% lower than the stresses obtained in other matrixes such as epoxy resin. The combination of sisal faces in a castor oil polyurethane matrix and honeycomb cores made in a 3D printer showed good properties, which allows the use of renewable, sustainable and less aggressive materials for the environment. In all tests, PETG was 21% to 32% stronger than PLA. Although there was no rupture in the test specimens, the PETG cores deformed 0.5% to 3.6% less than PLA. The composites with PLA were lighter, because the core density was 13.8% lower than the PETG cores. Increasing the height of the honeycomb increased its strength.

Development and characterization of a clay-based composite reinforced with doum fibers

This paper investigates the effects of Doum fiber as a local materials, on the mechanical strength properties of cylindrical earth samples with a diameter of 3 cm and a height of 4.5 cm. Untreated and Alkali treated Doum fiber with a NaOH concentration of 1%, 4%, 6% are introduced in local clay with a ratio of 0.5%, 1% and 1.5% by weight of the earth samples. A tensile test of the Doum fiber and a compressive strength test of the elaborated specimens is conducted. The study findings outline an improvement in the mechanical properties of the earth samples and adherence between surface fiber and soil when the fiber is treated. And a dosage of 0.5% by weight of Alkali treated Doum fiber with a NaOH concentration of 1% is sufficient to achieve higher mechanical performances. Modifying the fiber surface through NaOH treatment enhances fiber adhesion to clay and improves the mechanical behavior of the biocomposite.

Evaluating physico-mechanical properties of NaOH-treated natural fibres: Effects of polyolefin

The bottle gourd plant fibres (BGPF) and okra fibres were processed and refined (w/w 6 % NaOH) before being incorporated with polyolefin (polypropylene) for composite fabrication using a blending technique. The polyolefin matrix is used to develop composites with 5 % okra fibres and varying percentages (25, 30, 35 and 40 %) of BGPF. The results indicated that the "35 % BGPF +5 % okra +60 % polypropylene" composition achieved remarkable mechanical properties with tensile strength (26.95 MPa), tensile modulus (3.16 GPa), decreased elongation at break (1.71 %), bending strength (52.53 MPa), bending modulus (3.45 GPa), impact strength (14.25 kJ/m2), and hardness (69 D-shore). Moreover, these composites absorbed minimal water when a specific portion was submerged. The scanning electron microscopy (SEM) test on the composites revealed good fibre adhesion and adherence content between BGPF and okra fibres. Additionally, the thermo-gravimetric analysis and differential scanning calorimetry exhibited weight loss of composites during maximum cellulose degradation (80 %) at 483 °C. In the composites of the fibre-PP matrix, two distinct physical changes were observed indicating glass transition and degradation. However, the mechanical properties decreased after soil degradation. Thus, remarkable properties were achieved for the fibres-fibres and fibres-polyolefin (polypropylene) interfacial interactions.

Study of alkali and acetylation treatments on sisal fibers compatibility with low-amine/epoxy stoichiometric ratio

Sisal fibers are one of the most commercially utilized as reinforcing agents in composite materials. However, sisal fibers are very hydrophilic because they contain many hydroxyl groups, so their interfacial bonding is low when mixed with a non-polar polymer matrix. One method to improve the fiber-matrix interfacial bond is to modify the sisal fiber surface with chemical treatment. This study evaluated the influence of various chemical treatments on the tensile properties and interfacial adhesion of sisal fibers reinforced with low-amine/epoxy stoichiometric ratio resin. The sisal fibers were subjected to a series of treatments, including 2 wt% alkali for 4 h, acetylation for 1 h, and a combined alkali and acetylation treatment. The FT-IR analysis confirmed the success of the acetylation process by the presence of the carbonyl signal (1728 cm−1). The XRD analysis indicated that the crystallinity index of the sisal fiber (65 %) was increased after alkali (75 %) and acetylation (66 %) treatments. The alkali-treated sisal fibers showed the highest tensile strength (728 MPa) but the lowest interfacial shear strength (17.7 MPa). The acetylated-treated sisal fibers exhibited the highest tensile modulus (44.5 GPa) and interfacial shear strength (25 MPa). However, the combination of alkali and acetylation treatments reduced the tensile strength of the fiber from 659 to 619 MPa. The TGA results revealed that the maximum degradation temperature of sisal fibers (344 °C) was increased after alkali (349 °C), acetylation (348 °C), and a combination of alkali and acetylation (350 °C) treatments. The results suggest that acetylation treatment is highly beneficial for advanced composite applications.

Investigation of Titanium Nitride as an Effective Interphase for Carbon-Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites.

Ceramic matrix composites (CMCs) have played a significant role in increasing the efficiency of gas turbine engines. CMCs combine the high temperature resistance of ceramics with the high mechanical strength of ceramic fibers into a single unit. Interphase layers are a crucial component in CMCs, as they prevent ceramic fibers from oxidation and introduce strengthening mechanisms into the composite. Hexagonal boron nitride and pyrolytic carbon are the most commonly used interphase layers in the aerospace industry. Other than that, very few materials have been evaluated as interphase layers. In this study, we explore the possibilities of using titanium nitride as an interphase layer in single-tow CMCs (mini composite) representative of a unidirectional composite at a smaller scale. T-300 carbon fibers were coated with TiN by atmospheric pressure chemical vapor infiltration using TiCl4, N2, and H2. The deposition temperature, precursor flow rate ratio, total precursor flow rate, and deposition time were optimized to obtain high-quality coatings. The best coating was produced at 800 °C, 4:1 H2 [TiCl4]/N2 ratio, 125 standard cubic centimeters per minute (N2 + H2 [TiCl4]) total flow precursor flow rate, and 2 h of deposition time. At these conditions, the coatings displayed good fiber coverage, good fiber adhesion, minimum fiber linkage, and minimum surface roughness. There was minimum fiber degradation after TiN coating, with a retention of 95% of the initial Young's modulus and 26% of the ultimate tensile strength of the carbon fiber. Adding the TiN interphase coating to the Cf/SiC CMC increased the ultimate tensile strength of the composite by 1122% and Young's modulus by 150%.

Benzo[b]fluoranthene damages coronary artery and affects atherosclerosis markers in mice and umbilical vein endothelial cells

Polycyclic aromatic hydrocarbons (PAHs) exposure is associated with cardiovascular diseases. Toxic effects of PAHs are diverse, while cardiovascular consequences of benzo[b]fluoranthene (B[b]F) are unclear. Here, we reported the impacts of B[b]F on coronary artery and atherosclerosis markers both in mice and umbilical vein endothelial EAhy.926 cells. In mice, we found that B[b]F decreases heart-to-body weight ratio, affects aortic physiology, elevates serum low-density lipoprotein and total cholesterol, increases aortic levels of collagen fiber and atherosclerotic marker vascular cell adhesion molecule-1 (VCAM-1), and downregulates oxidative stress related nuclear factor erythroid 2-related factor 2 (Nrf2). In EAhy.926 cells, we showed that B[b]F inhibits cell proliferation and migration in a dose-dependent manner, induces cell cycle arrest and apoptosis, increases reactive oxygen species, upregulates VCAM-1 level, and suppresses expression of Nrf2. Taken together, our findings reveal that B[b]F exposure may contribute to coronary artery damage and potentially induce atherosclerosis, possibly via the Nrf2-related signaling pathways.

Analyses and control of interphase structures and adhesion properties of epoxy resin/epoxy resin for development of CFRP adhesion systems

In the adhesion of carbon fiber reinforced plastics (CFRP), the boundary regions were composed of only epoxy resins of CFRP matrix and adhesives, and their similar epoxy structures pose significant difficulty in studying the adhesion mechanism. Herein, we focused on structure and properties of laminates of epoxy resin substrates and adhesives with different curing conditions of substrates. We prepared laminates using deuterated epoxy adhesives or fluorinated epoxy adhesives, and their boundary regions were identified through confocal Raman scattering measurements. The regions were distributed into “penetration” and “interphase”. In particular, the penetration phase is a key of the adhesion properties. The penetration behaviors strongly depended on the crosslinking densities of the adherends, suggesting that the penetration regions would be directly impacted by the curing conditions of the substrates and molecular size of epoxy adhesive precursors. Our findings provide insights into novel designs of the reliable adhesion-based manufacturing systems of CFRP.

Effect of fiber surface treatment with silane coupling agents and carbon nanotubes on mechanical properties of carbon fiber reinforced polyamide 6 composites

AbstractThe mechanical properties of carbon fiber (CF) reinforced thermoplastic polymer composites are primarily governed by the interphase between CFs and matrix. However, the inherent inertness of CF surfaces combined with the high viscosity and processing temperatures of thermoplastic resin often result in relatively weak interfacial bonding. This study aims to enhance the interfacial adhesion of carbon fiber reinforced polyamide 6 composites to improve their mechanical properties. CFs were de‐sized and oxidized, followed by re‐sizing with silanized carbon nanotubes. Fracture morphology and composition analysis of the fibers were conducted, and the fibers were subsequently incorporated into composites for mechanical testing. Results revealed a 20.0% increase in tensile strength, a 25.11% increase in flexural strength, and a 24.88% increase in interlaminar shear strength for the resized‐carbon fiber reinforced polyamide 6 composites compared to the pristine‐carbon fiber reinforced polyamide composites. The cross‐sectional morphology of the modified composites exhibited a zig‐zag fracture pattern. Dynamic mechanical analysis indicated that the modified fibers required higher activation energy for the free movement of the polyamide 6 molecular chain. These findings suggest that surface treatment enhances the interfacial adhesive between CF and resin, thereby significantly improving the mechanical properties of carbon fiber reinforced polyamide 6 composites.Highlights An efficient and reliable carbon fiber surface treatment method is proposed. Surface modification improves surface chemical activity of carbon fibers. Composites show substantial improvements in mechanical properties. Interfacial performance enhancement mechanism of composite was revealed.

Microhardness and Pushout Bond Strength of Glass Fiber Post-to-Canal Dentin Irrigated with Boric Acid, Nd: YAP, AgNPs, and Curcumin Activated with Microbubble Emulsion. A SEM, EDX Analysis

This study aimed to assess the microhardness (MH) and push-out bond strength (PBS) of fiber post-to-canal dentin when boric acid (BA), Nd: YAP, silver nanoparticles (AgNPs), and microbubble emulsion (MBE) with curcumin were used as irrigants. Canal therapy was performed and the post space was prepared. Prior to glass fiber post (GFP) insertion, the post space was irrigated using 2.5% NaOCl+17% EDTA, 10% BA+EDTA, Nd: YAP laser+EDTA, AgNP+EDTA, and MBE (curcumin)+EDTA. Following disinfection, microhardness was evaluated. GFP was then inserted and PBS was assessed at the coronal, middle, and apical levels, along with the examination of debonded surfaces via stereomicroscope. The data were analyzed using ANOVA and a Post Hoc Tukey HSD test. The results showed that MH was highest in the group treated with AgNP+EDTA and lowest in the group treated with 10% BA+EDTA. Within the cervical region, the Nd: YAP laser+EDTA group showed the lowest PBS, while the highest PBS was observed in the group treated with MBE (curcumin)+EDTA. In the middle region, the GFP bonded to canal dentin disinfected with 2.5% NaOCl+EDTA was comparable to that treated with Nd: YAP laser+EDTA. In the apical region, the PBS of GFP was highest in the canal disinfected with MBE (curcumin)+EDTA. The study concluded that silver nanoparticles+EDTA and curcumin photosensitizer via microbubble emulsion+EDTA have the potential to be used as alternatives to conventional methods for improving the adhesion of glass fiber post-to-canal dentin, along with enhancing microhardness.

Research on the spatial quantity distribution of fibers in ultra high performance concrete slabs based on image recognition method

In this paper, the detection of fiber distribution in six UHPC slabs with fiber content of 1%, 2%, 3%, and horizontal pouring and vertical pouring is studied by image recognition method. The results show that: firstly, the fiber distribution can be identified by a series of processing steps, such as grayscale and binarization of fiber source image, extraction of initial detection area, extraction of fiber contour and segmentation of fiber adhesion area. Furthermore, it is proposed that the scaling curve of n-e detection area per pixel of fiber number can anchor the effective recognition area range of fiber. Secondly, the statistical analysis of the identification results can visually draw the fiber distribution maps of different types of UHPC slabs in different directions, and quantitatively characterize the fiber distribution uniformity of UHPC slabs by quoting the evaluation index of fiber distribution coefficient. Finally, the cross-sectional fiber Scatter Density Plot can perceptually show the degree of fiber dispersion and its position distribution. The more uniform the color, the more uniform the fiber distribution in the cross-section of the specimen.

TLNRD1 is a CCM complex component and regulates endothelial barrier integrity.

We previously identified talin rod domain-containing protein 1 (TLNRD1) as a potent actin-bundling protein in vitro. Here, we report that TLNRD1 is expressed in the vasculature in vivo. Its depletion leads to vascular abnormalities in vivo and modulation of endothelial cell monolayer integrity in vitro. We demonstrate that TLNRD1 is a component of the cerebral cavernous malformations (CCM) complex through its direct interaction with CCM2, which is mediated by a hydrophobic C-terminal helix in CCM2 that attaches to a hydrophobic groove on the four-helix domain of TLNRD1. Disruption of this binding interface leads to CCM2 and TLNRD1 accumulation in the nucleus and actin fibers. Our findings indicate that CCM2 controls TLNRD1 localization to the cytoplasm and inhibits its actin-bundling activity and that the CCM2-TLNRD1 interaction impacts endothelial actin stress fiber and focal adhesion formation. Based on these results, we propose a new pathway by which the CCM complex modulates the actin cytoskeleton and vascular integrity.