Matrix Layer Research Articles

High-Cycle Fatigue Fracture Behavior and Stress Prediction of Ni-Based Single-Crystal Superalloy with Film Cooling Hole Drilled Using Femtosecond Laser

A high-temperature, high-cycle fatigue test was conducted on a nickel-based single-crystal superalloy with a pore structure. Optical and scanning electron microscopy were utilized to examine the crack propagation paths and fatigue fracture surfaces at the macro and micro scales. The analysis of crack initiation and propagation related to the pore structure facilitated the development of a crack shape factor reflecting these distinct fracture behaviors. Predictions about the high-cycle fatigue stress experienced by the specimen were made, accompanied by an error analysis, providing critical insights for precise stress calculations and structural optimization in engine blade design. The results reveal that high-cycle fatigue cracks originate from corner cracks at pore edges, with the initial propagation displaying smooth crystallographic plane features. Subsequent stages show clear fatigue arc patterns in the propagation zones. The fracture surface exhibits the significant layering of oxide layers, primarily composed of NiO, with traces of CoO displaying columnar growth. AL2O3 is predominantly found at the interfaces between the matrix and oxide layers. Short and straight dislocations near the oxide layers and within the matrix suggest that dislocation multiplication and planar slip dominate the slip mechanisms in this alloy. The orientation of the fracture surface is mainly perpendicular to the load direction, with minor inclined facets in localized areas. Correlations were established between the plastic zone dimensions at the crack tips and the corresponding fatigue stresses. Without grain boundaries in single-crystal alloys, these dimensions are easily derived as parameters for fatigue stress analysis. The selected crack shape factor, “elliptical corner crack at pore edges”, captures the initiation and propagation traits relevant to porous structures. Subsequent calculations, accounting for the impact of oxide layers on stress assessments, indicated an error ratio ranging from 1.00 to 1.21 compared to nominal stress values.

Supernatant of plant-associated bacteria potency against biofilms formed by foodborne pathogen and food spoilage bacteria

ObjectivesFood products are often contaminated by pathogens and spoilage bacteria. Most of them can form biofilms, a community of cells embedded in protective extracellular matrix layers resistant to harsh conditions, including antibiotics. Therefore, alternative antibiofilm agents are required to overcome biofilm formation. This study aims to determine and quantify the antibiofilm activity of supernatants from plant-associated bacteria against biofilms of foodborne pathogen and food spoilage bacterium, namely Bacillus cereus and Bacillus subtilis.ResultsPlant-associated bacteria (PAB) have shown promising antibiofilm activities against biofilm-forming pathogens in previous studies. Thirteen PAB isolated from Ternate, Indonesia were used in this study. Supernatants of PAB were subjected to antimicrobial activity and quorum quenching detection, both using the well diffusion method. Four supernatants inhibited the growth of B. subtilis, but none affected the growth of B. cereus. Eight supernatants were able to disrupt the quorum sensing system of an indicator bacterium, wild-type Chromobacterium violaceum. Biofilm inhibition and destruction were quantified using 96-well microplates. The highest biofilm inhibition and destruction activities of PAB supernatants against each of B. cereus and B. subtilis biofilms were > 76%, and were later confirmed by light microscope and scanning electron microscope. Brine shrimp lethality assay (BSLA) was conducted and revealed that the selected PAB supernatants were non-toxic. The 16S rRNA gene of PAB were sequenced and they showed similarities to Bacillus, Priestia, and Chryseobacterium. Compounds in the supernatants were determined by GC–MS which revealed contents of fatty acids, ethyl esters, and diketopiperazines. Therefore, PAB supernatants have potential as antibiofilm agents against biofilm formed by Bacillus cereus and Bacillus subtilis.

Efficient Defect-Driven Cation Exchange beyond the Nanoscale Semiconductors toward Antibacterial Functionalization.

Defect engineering is an exciting tool for customizing semiconductors' structural and optoelectronic properties. Elaborating programmable methodologies to circumvent energy constraints in multievent inversions expands our understanding of the mechanisms governing the functionalization of nanomaterials. Herein, we introduce a novel strategy based on defect incorporation and solution rationalization, which triggers energetically unfavorable cation exchange reactions in extended solids. Using Sb2X3 + Ag (I) → Ag: Sb2X3 (X= S, Se) as a system to model, we demonstrate that incorporating chalcogen vacancies and AgSbVX complex defects into initial thin films (TFs) is crucial for activating long-range solid-state ion diffusion. Additional regulation of the Lewis acidity of auxiliary chemicals provides an exceptional conversion yield of the Ag precursor into a solid-state product up to 90%, simultaneously transforming upper matrix layers into AgSbX2. The proposed strategy enables tailoring radiative recombination processes, offers efficiency to invert TFs at moderate temperatures quickly, and yields structures of large areas with substantial antibacterial activity in visible light for a particular inversion system. Similar customization can be applied to most sulfides/selenides with controlled reaction yields.

The effect of positive and reverse current cycles on the wettability, morphology, and corrosion behaviour of electrodeposited nickel matrix layer

ABSTRACT In this study, Ni-TiO2 coatings were formed using a multi-step pulse method with positive and, in some cases, reverse current steps. All coatings were produced at a current density of 4 A dm−2 and a frequency and duty cycle of 10 Hz and 10%, respectively with a thickness of 30 µm. The results showed that by applying the reverse current cycle, the codeposition of TiO2 particles in the coating decreased and the morphology of the coating became irregular. It was found that the effect of the wetting angle of the coating is greater than the incorporation of TiO2 particles on the corrosion behaviour of the coating. Thus, a coating was created with a positive 4-step pulse current with the lowest amount of TiO2 particles (7.7 vol.%) having the highest resistance against corrosion. The sample had compact morphology and high wetting angle (82.61o֯).

The Role of Fabricated Coral Shell Powder in the Healing of Mandibular Bone Gap in Dogs

Background: The reconstruction of mandibular bone defects poses a real challenge and difficulty for surgeons; biomaterial bone substitutes are the most used material for reconstructing mandibular bone defects. Objectives: This study explored the role of fabricated hydroxyapatite (HAp) powder from the coral shell in healing critical size mandible gaps in dogs. Methods: HAp was prepared using the hydrothermal method from coral shells. Characterization of the fabricated coral shell was done by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive x-ray spectroscopy (EDX). The designed research was performed on 18 dogs of both sexes (mean weight: 20±0.5 kg, mean age: 2±0.6 years). The samples were divided into two equal groups. Animals underwent experimental defects at the ventral surface of the lower mandible about 14.5 mm. Results: The results of XRD represented high crystallinity, the EDX results indicated the surface morphology of distributed particles of calcium, phosphorous, carbon, and oxygen, respectively, and the FESEM results suggested that the surface morphology of HAp appears as a spherical particle that regularly distributed within the sample. In the HAp group, at 30 days, the FESEM images show that the defective gap completely closed, and the center of the defect was filled with a thick layer of osteoid matrix. Radiographically, the HAp group at 30 days post-surgery indicated a well-defined circular radiolucent bone gap at the caudal portion of the mandible, with a partially sclerosed margin. Macroscopically, at 30 days, the gap appears very small and is invaded by new bone formation. Conclusion: In conclusion, recycling HAp from coral shells has practical value in the reconstitution of the mandibular gap, and the radiological and critical properties of prepared HAp emphasize this outcome.

Magnetorheological and magnetic actuation behaviour of solvent cast 4D printed styrene-ethylene-butylene-styrene block copolymer based magnetorheological elastomeric materials

In this work styrene-ethylene-butylene-styrene (SEBS) block copolymer based smart magnetorheological elastomeric (MREs) materials have been additively manufactured using solvent-cast 4D Printing (SC-4DP) technique. The effect of carbonyl iron powder (CIP) content on the particle distribution, particle–matrix adhesion, surface and layer morphology of the 4D Printed MRE sample was investigated. CIP particles were observed to be well embedded and dispersed up to 60 wt% content. However, at higher CIP content the tendency of the particles to agglomerate increased significantly. Furthermore, samples with CIP content ≥70 wt% showed poor particle–matrix adhesion and possessed inter-layer coalescence defects. Investigations were also performed to evaluate the magnetic properties of MREs at room temperature. Magnetorheological behaviour was studied to evaluate the effect of varying magnetic field on dynamic viscoelastic properties. Magnetorheological effect increased from ∼79 % to ∼211 % with an increase in CIP content. However, the particle–matrix adhesion also significantly affected the magnetorheological effect for higher CIP content samples. Magnetic actuation capability of flexible MRE samples was evaluated for gripper-based application. SC-4D Printed flexible grippers were able to successfully grip, lift, and drop both the soft deformable and rigid freeform profile objects in different media (air and sodium hydroxide solution) suggesting suitability for remotely actuated gripper-based applications.

Copper‐graphene coatings for improving thermal shielding of CFRPs through electrodeposition techniques

AbstractToday, carbon fiber reinforced plastics (CFRPs) are materials of interest several industrial sectors because of their mechanical properties and low weight. However, applications in high‐temperature areas are limited because of thermal degradation. Thus, thin coatings acting as thermal shielding and ensuring the upkeep of CFRP structural stiffness are of high interest. This work presents an innovative approach to produce copper/graphene bilayer coatings through electrodeposition and electrophoretic deposition; it consists of laser pre‐treatment of the composite surface to remove the matrix layer exposing the carbon fibers, enabling the subsequent deposition. Bi‐layer graphene/copper coatings exhibit an enhancement in copper electrodeposition efficiency of more than 59% resulting in a 97% stiffness improvement compared to the single layer copper electroplating. All the obtained coatings were able to act as a thermal shield of the CFRPs, reducing the maximum temperature of the composite by more than 60%. In particular, due to the synergistic effect of copper and graphene, the GNPs‐Cu coating achieved the highest maximum temperature reduction (81%). Cross‐sectional analysis indicates severe delamination in uncoated CFRPs, whereas double‐layer coatings maintain structural integrity and prevent delamination even under high‐energy exposure. In addition, the coated composites exhibit a higher electrical conductivity compared to the laser cleaned CFRP, with the GNPs‐Cu coating that obtained a 90% enhancement because of the outstanding electrical properties of copper and graphene.Highlights The laser cleaning pretreatment allows the electrodepositions on CFRPs. The GNP‐Cu scenario achieves the highest deposition efficiency. A 97% stiffness improvement was achieved by GNPs‐Cu scenario. GNPs‐Cu coatings exhibit the utmost reduction in resistivity (98%). The GNPs‐Cu coating achieves the highest thermal shielding performance (81%).

Development of dual drug loaded-hydrogel scaffold combining microfluidics and coaxial 3D-printing for intravitreal implantation

Treating diabetic retinopathy (DR) effectively is challenging, aiming for high efficacy with minimal discomfort. While intravitreal injection is the current standard, it has several disadvantages. Implantable systems offer an alternative, less invasive, with long-lasting effects drug delivery system (DDS). The current study aims to develop a soft, minimally invasive, biodegradable, and bioadhesive material-based hydrogel scaffold to prevent common issues with implants. A grid-shaped scaffold was created using coaxial 3D printing (3DP) to extrude two bioinks in a single filament. The scaffold comprises an inner core of curcumin-loaded liposomes (CUR-LPs) that prepared by microfluidics (MFs) embedded in a hydrogel of hydroxyethyl cellulose (HEC), and an outer layer of hyaluronic acid-chitosan matrix with free resveratrol (RSV), delivering two Sirt1 agonists synergistically activating Sirt1 downregulated in DR. Optimized liposomes, prepared via MFs, exhibit suitable properties for retinal delivery in terms of size (<200 nm), polydispersity index (PDI) (<0.3), neutral zeta potential (ZP), encapsulation efficiency (∼97 %), and stability up to 4 weeks. Mechanical studies confirm scaffold elasticity for easy implantation. The release profiles show sustained release of both molecules, with different patterns related to different localization of the molecules. RSV released initially after 30 min with a total release more than 90 % at 336 h. CUR release starts after 24 h with only 4.78 % of CUR released before and gradually released thanks to its internal localization in the scaffold. Liposomes and hydrogels can generate dual drug-loaded 3D structures with sustained release. Microscopic analysis confirms optimal distribution of liposomes within the hydrogel scaffold. The latter resulted compatible in vitro with human retinal microvascular endothelial cells up to 72 h of exposition. The hydrogel scaffold, composed of hyaluronic acid and chitosan, shows promise for prolonged treatment and minimally invasive surgery.

Exploring the potential of tomato juice (Solanum lycopersicum L.) patch for tooth bleaching.

Tomato, renowned for its tooth-whitening properties due to its hydrogen peroxide and peroxidase enzyme content, requires formulation for enhanced applicability. This study assessed the dental whitening efficacy of a patch containing tomato juice as the active ingredient. Tomato juice patches were formulated at concentrations of 55%, 60%, and 65%. A control group (C) containing a 12% hydrogen peroxide patch was also included. A matrix layer of the patches was prepared using the solvent casting method at 40 for 18 h, with TegadermTM applied as the backing layer. For the dental whitening procedure, each group of patches was applied to the labial surface of anterior stained teeth (n=6/group) for 3 h, repeated 14 times. Tooth brightness was evaluated qualitatively and quantitatively using digital dental photo CIEL*a*b* analysis. Meanwhile, enamel surfaces were examined under a scanning electron microscope (SEM). Repeated-measures analysis of variance (ANOVA) was employed for statistical analysis. The application of tomato juice patches led to enhanced tooth brightness. The patch containing 65% tomato juice significantly improved stained tooth brightness (P<0.05). SEM analysis revealed less enamel erosion with the 65% tomato juice patch compared to the 12% hydrogen peroxide patch. Tomato juice patches effectively increased tooth brightness while minimizing demineralization. Further research is needed to optimize formulation and explore its potential.

A tough Janus poly(vinyl alcohol)-based hydrogel for wound closure and anti postoperative adhesion

Traditional adhesive hydrogels perform well in tissue adhesion but they fail to prevent postoperative tissue adhesion. To address this challenge, a biodegradable Janus adhesive hydrogel (J-AH) was designed and fabricated by the assembly of three different functional layers including anti-adhesive layer, reinforceable layer, and wet tissue adhesive layer. Each layer of J-AH serves a specific function: the top zwitterionic polymeric anti-adhesive layer shows superior resistance to cell/protein and tissue adhesion; the middle poly(vinyl alcohol)/tannic acid reinforceable matrix layer endows the hydrogel with good mechanical toughness of ∼2.700 MJ/m3; the bottom poly(acrylic acid)/polyethyleneimine adhesive layer imparts tough adhesion (∼382.93 J/m2 of interfacial toughness) to wet tissues. In the rat liver and femoral injury models, J-AH could firmly adhere to the bleeding tissues to seal the wounds and exhibit impressive hemostatic efficiency. Moreover, in the in vivo adhesion/anti-adhesion assay of J-AH between the defected cecum and peritoneal walls, the top anti-adhesive layer can effectively inhibit undesired postoperative abdominal adhesion and inflammatory reaction. Therefore, this research may present a new strategy for the design of advanced bio-absorbable Janus adhesive hydrogels with multi-functions including tissue adhesion, anti-postoperative adhesion and biodegradation. Statement of significanceDespite many adhesive hydrogels with tough tissue adhesion capability have been reported, their proclivity for undesired postoperative adhesion remains a serious problem. The postoperative adhesion may lead to major complications and even endanger the lives of patients. The injectable hydrogels can cover the irregular wound and suppress the formation of postoperative adhesion. However, due to the lack of adhesive properties with tissue, it is difficult for the hydrogels to maintain on the wound surface, resulting in poor anti-postoperative adhesion effect. Herein, we design a Janus adhesive hydrogel (J-AH). J-AH integrates together robust wet tissue adhesion and anti-postoperative adhesion. Therefore, this research may present a new strategy for the design of advanced bio-absorbable Janus adhesive hydrogels.

The Effect of Synthetic Polyamine BPA-C8 on the Fertilization Process of Intact and Denuded Sea Urchin Eggs.

Sea urchin eggs are covered with layers of extracellular matrix, namely, the vitelline layer (VL) and jelly coat (JC). It has been shown that sea urchin eggs' JC components serve as chemoattractants or ligands for the receptor on the fertilizing sperm to promote the acrosome reaction. Moreover, the egg's VL provides receptors for conspecific sperm to bind, and, to date, at least two sperm receptors have been identified on the surface of sea urchin eggs. Interestingly, however, according to our previous work, denuded sea urchin eggs devoid of the JC and VL do not fail to become fertilized by sperm. Instead, they are bound and penetratedby multiple sperm, raising the possibility that an alternative pathway independent of the VL-residing sperm receptor may be at work. In this research, we studied the roles of the JC and VL using intact and denuded eggs and the synthetic polyamine BPA-C8. BPA-C8 is known to bind to the negatively charged macromolecular complexes in the cells, such as the JC, VL, and the plasma membrane of echinoderm eggs, as well as to the actin filaments in fibroblasts. Our results showed that, when added to seawater, BPA-C8 significantly repressed the Ca2+ wave in the intact P. lividus eggs at fertilization. In eggs deprived of the VL and JC, BPA-C8 binds to the plasma membrane and increases fibrous structures connecting microvilli, thereby allowing the denuded eggs to revert towards monospermy at fertilization. However, the reduced Ca2+ signal in denuded eggs was nullified compared to the intact eggs because removing the JC and VL already decreased the Ca2+ wave. BPA-C8 does not cross the VL and the cell membrane of unfertilized sea urchin eggs to diffuse into the cytoplasm at variance with the fibroblasts. Indeed, the jasplakinolide-induced polymerization of subplasmalemmal actin filaments was inhibited in the eggs microinjected with BPA-C8, but not in the ones bath-incubated with the same dose of BPA-C8.

Investigation on 2D SiCf/SiC composite scribing mechanism by single- and double-grit

To validate the proposed removal mechanism of 2D SiCf/SiC composite, single- and double-grit scribing experiments were conducted on the fiber woven surface (WS) and stacking surface (SS) along the 0°, 45°, and 90°. The results indicate that transverse fibers mainly undergo shear, tensile, and bending fractures. The removal modes of normal fibers are shear and bending fractures. The longitudinal fibers are damaged by tensile (cut-in side) and bending (cut-off side) fractures, accompanied by fiber peel-off. The removal forms of the matrix include crack propagation, ductile scratch, powdery removal, and brittle peel-off. The order of scribing force is FSS0 > FWS45 > FSS90 > FWS0. The maximum and minimum scribing force occur on SS0 and WS0, respectively, due to the powdery removal of matrix and fibers + matrix peel-off. The 2nd grit scribes the matrix layer and fiber tip in a very low depth to cause powdery and ductile removal, which exhibit the different material removal mechanism with the 1st grit. The scribing damage formed by 1st grit greatly reduces the force required by the 2nd grit for the same material removal volume. The coupling effect among grits in multi-grit scribing and grinding cannot be ignored.

A comparison of physical, morphological, and mechanical properties of bio‐polyester hybrid nanocomposites

AbstractIt is imperative to improve the physical, morphological, and mechanical properties of biodegradable polymers like polylactic acid (PLA), poly (butylene adipate‐co‐terephthalate) (PBAT), and polycaprolactone (PCL) in order to employ them on a larger scale. The development of hybrid nanocomposite materials using nano inclusions can improve desired qualities. Here we introduced an interactive nano reinforcement approach to improve the properties by combining graphene oxide (GO) and carboxyl functionalized MWCNT (f‐MWCNT), to provide for their chemical bonding for synergic reinforcement. A constant filler 2 wt.% was added to the biopolyesters by melt blending process and examined the different physical properties like water absorption, intrinsic viscosity, and hardness. To completely evaluate the functionalization of the nanofillers, wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy and Fourier transform infrared radiation (FTIR) analyses were used. The paired nanoparticles and polymer matrix appear to mix well together, as shown by electron microscopy, which also reveals good dispersion and the creation of a reinforcing network microstructure across the matrix layer. A thorough analysis of the results showed that effective stress transmission, delaying the start of faults and generating microcracks, and dissipating additional mechanical energy all contributed to efficient hybrid network formation, which improved the mechanical properties of hybrid filler nanocomposites except some nanocomposites. These findings offer a viable technique for chemically altering biodegradable polymers, like PLA, PBAT, and PCL for use in biomedical, wastewater management, and agricultural applications.

Harnessing the Biomimetic Effect of Macromolecular Crowding in the Cell-Derived Model of Clubfoot Fibrosis.

Fibrotic changes in pediatric clubfoot provide an opportunity to improve corrective therapy and prevent relapses with targeted drugs. This study defines the parameters of clubfoot fibrosis and presents a unique analysis of a simple pseudo-3D in vitro model for disease-specific high-throughput drug screening experiments. The model combines clubfoot-derived fibroblasts with a biomimetic cultivation environment induced by the water-soluble polymers Ficoll and Polyvinylpyrrolidone, utilizing the principle of macromolecular crowding. We achieved higher conversion of soluble collagen into insoluble collagen, accelerated formation of the extracellular matrix layer and upregulated fibrosis-related genes in the mixed Ficoll environment. To test the model, we evaluated the effect of a potential antifibrotic drug, minoxidil, emphasizing collagen content and cross-linking. While the model amplified overall collagen deposition, minoxidil effectively blocked the expression of lysyl hydroxylases, which are responsible for the increased occurrence of specific collagen cross-linking in various fibrotic tissues. This limited the formation of collagen cross-link in both the model and control environments. Our findings provide a tool for expanding preclinical research for clubfoot and similar fibroproliferative conditions.

Interface construction of crosslinked hyperbranched polyamidoamine between silver layer and poly(meta-phenylene isophthalamide) fiber to enhance conductivity and its resilience to adverse conditions

High-performance silvered poly(meta-phenylene isophthalamide) (PMIA) fiber can be applied in antistatic, conductive, electromagnetic interference shielding and other fields, whereas achieving good interface bonding of silver layer to PMIA matrix remains a grand challenge. This paper studies a method of constructing multi-structure interface between silver layer and PMIA fiber. First, crosslinked hyperbranched polyamidoamine (HPAMAM), referred to as xHP-Qy, was introduced onto PMIA by means of a dip-coating method. Then, the modified fiber was surface metallized by silver ammonia solution and glucose solution to prepare a silver-coated fiber. The structure, morphology and properties of as-prepared materials were characterized systematically. The results show that the final fiber exhibits a low electrical resistivity (5.95 × 10−5 Ω·cm) without sacrificing the thermal stability and mechanical performance of the PMIA itself, which is attributed to the distinct antenna-shaped structure of xHP-Qy between PMIA matrix and Ag layer. In addition, the functionalized composite fiber preserves low resistivity even after subjecting harsh environment and mechanical deformation. The strategy paves a promising avenue for the fabrication of high-performance fiber with enormous potential application for electromagnetic interference shielding, electrical heating and flexible sensor materials.

Countercurrent Imbibition in Porous Media with Dense and Parallel Microfractures: Numerical and Analytical Study

Summary Countercurrent imbibition is the process in which the wetting fluid spontaneously displaces the nonwetting fluid, while the nonwetting fluid is recovered at the wetting fluid inlet. It is a major mechanism for the recovery of shale oil, shale gas, and tight oil. In shale and tight formations, microfractures are highly developed. Specifically, some typical formations, such as continental shales, consist of dense and parallel microfractures (DPFs). In DPF systems, microfractures are segregated by low-permeability matrix layers, while the very close distance betwen neighboring microfractures results in strong capillary correlation. The underlying assumptions of the classical dual-porosity (DP) model break down. Despite extensive studies on layered media, there is still no suitable model to describe imbibition in the DPF system at the representative elementary volume (REV) scale. In this study, we first numerically simulate countercurrent imbibition in DPF systems with fine grids, adopting typical continental shale parameters. For imbibition parallel to microfractures, two distinct stages are identified: an early stage where fractures are not correlated and a late stage where neighboring fractures are strongly correlated by capillarity. In both stages, cumulative oil production (Q) is proportional to the square root of imbibition time (t1/2), while the prefactors are very different. The late stage is the dominant stage in oil recovery. We note that the matrix permeability rarely contributes to imbibition parallel to microfractures at the late time, indicating that the matrix’s role here is to store fluid rather than to provide flow resistance. In addition, we rationalize the failure of the classical DP model, as it significantly overestimates fracture-matrix fluid exchange near the displacement front. Similarly, for imbibition perpendicular to microfractures, Q is also proportional to t1/2 in the late stage. After elucidating the mechanisms of fracture-fracture capillary interaction, we successfully derive analytical solutions for uni-directional countercurrent imbibition kinetics in DPF systems at the late stage, for imbibition parrallel and perpendicular to microfractures, respectively. We accordingly propose an equivalent REV scale model and examine it with fine-grid simulations. We highlight the importance of adopting anisotropic relative permeability in this DPF system at REV scale for reservoir simulation rather than simply adopting anisotropic absolute permeability. This presents a new challenge for numerical simulations at reservoir scale.

Alternative Strategy to Analyze In Vitro Cell Invasion of 3D Cultures.

Spheroid culture is a 3D model that provides an improved replication of the in vivo microenvironment compared to traditional two-dimensional (2D) cultures. Invasion is a cellular outcome of utmost interest in cancer biology. In this protocol, we have devised an alternative strategy for evaluating cancer cell invasion in vitro, employing heterospheroids comprised of oral squamous cell carcinoma (OSCC), cancer-associated fibroblasts (CAF), and monocytes. These heterospheroids aim to mimic the tumor microenvironment (TME), including two relevant non-neoplastic cell types alongside the cancer cells. Each cell type was labeled with vital fluorescent markers emitting in distinct wavelengths before spheroid formation. Once formed, heterospheroids were seeded onto a layer of human leiomyoma-derived extracellular matrix in the upper compartment of a microporous membrane. Invasion was assessed in the z-axis using confocal microscopy. Digital images were obtained in the corresponding fluorescent channels at 10 µm intervals, covering a depth of 90 µm in the z-axis. Analysis was performed using freeware image software by calculating the integrated fluorescence intensity in each image and fluorescence channel. This approach enables a more dynamic analysis of cell invasion patterns in a multilayered context, as well as the examination of spatial co-localization of different cell types during invasion.

Numerical and Experimental Study on Balanced Performance and Axial Stiffness of Fiber-Reinforced Rubber Pipe.

Balanced fiber-reinforced rubber (FRR) pipes not only provide displacement compensation when transporting pressurized media but also prevent additional forces and displacements from being exerted on the connected pipeline system. Investigating the balanced performance of FRR pipes and the axial stiffness of balanced pipes is crucial for optimizing pipeline design and improving the reliability of pipeline systems. This paper develops a numerical model of FRR pipes that considers the nonlinearity of the rubber material and the interaction between the rubber matrix and fiber-reinforced layers. Using this model, the balanced performance of the pipe is calculated, and its axial stiffness under combined internal pressure and axial load is analyzed. Numerical results are compared with experimental data for validation. The results indicate that the pipe's balance is achieved through the combined effects of the elongation and rotation of the reinforcing fibers and the deformation of the rubber matrix, highlighting the significant impact of the rubber matrix on the mechanical performance of the FRR pipe. Furthermore, the pipe's balanced performance and axial stiffness are highly sensitive to the winding angle of reinforcing fibers. The proposed numerical model fills the gap in using numerical methods to evaluate the balanced performance of FRR pipes and provides valuable insights for their design and optimization.

Cellular endosomal potassium ion flux regulates arenavirus uncoating during virus entry.

Lymphocytic choriomeningitis virus (LCMV) is an enveloped and segmented negative-sense RNA virus classified within the Arenaviridae family of the Bunyavirales order. LCMV is associated with fatal disease in immunocompromised populations and, as the prototypical arenavirus member, acts as a model for the many highly pathogenic members of the Arenaviridae family, such as Junín, Lassa, and Lujo viruses, all of which are associated with devastating hemorrhagic fevers. To enter cells, the LCMV envelope fuses with late endosomal membranes, for which two established requirements are low pH and interaction between the LCMV glycoprotein (GP) spike and secondary receptor CD164. LCMV subsequently uncoats, where the RNA genome-associated nucleoprotein (NP) separates from the Z protein matrix layer, releasing the viral genome into the cytosol. To further examine LCMV endosome escape, we performed an siRNA screen which identified host cell potassium ion (K+) channels as important for LCMV infection, with pharmacological inhibition confirming K+ channel involvement during the LCMV entry phase completely abrogating productive infection. To better understand the K+-mediated block in infection, we tracked incoming virions along their entry pathway under physiological conditions, where uncoating was signified by separation of NP and Z proteins. In contrast, K+ channel blockade prevented uncoating, trapping virions within Rab7 and CD164-positive endosomes, identifying K+ as a third LCMV entry requirement. K+ did not increase GP-CD164 binding or alter GP-CD164-dependent fusion. Thus, we propose that K+ mediates uncoating by modulating NP-Z interactions within the virion interior. These results suggest K+ channels represent a potential anti-arenaviral target.IMPORTANCEArenaviruses can cause fatal human disease for which approved preventative or therapeutic options are not available. Here, using the prototypical LCMV, we identified K+ channels as critical for arenavirus infection, playing a vital role during the entry phase of the infection cycle. We showed that blocking K+ channel function resulted in entrapment of LCMV particles within late endosomal compartments, thus preventing productive replication. Our data suggest K+ is required for LCMV uncoating and genome release by modulating interactions between the viral nucleoprotein and the matrix protein layer inside the virus particle.

Simple double shooting approach with bisection for FRCM reinforced curved masonry prisms subjected to shear

In this study, curved masonry pillars reinforced with FRCM subjected to standard shear tests are analyzed through a novel mono-dimensional model, where failure is governed by Mode II. Three approaches with different accuracy are proposed: i) the first, where the outer matrix is neglected; ii) the second, where the inner matrix is assumed rigid; and iii) the third which considers both matrix layers. Matrix and fiber are assumed subjected to a monoaxial state of stress and exchange tangential stresses at the interfaces. The load is applied by incrementing the displacement at the free fiber edge. Material properties of matrix, fiber and interfaces are assumed constant on small portions of the bonded length. Non-linearity is considered penalizing the elastic modulus using the results of the previous time step. The substrate is assumed rigid. The substrate curvature influence is manifested through interface normal stresses, incorporated into the bond-slip constitutive behavior via the Mohr-Coulomb law. The normal stresses can be determined by enforcing radial equilibrium. For the first two models, the field problem is constituted by a system of two 2nd order differential equations into two variables, namely the displacement of the inner (or outer) layer of mortar and of the fiber textile. A 1D shooting is employed, after having converted the boundary value problem (BVP) into an initial value one (IVP), being the latter fully explicit. For the third model, the field problem is constituted by a system of three 2nd order differential equations, and an additional displacement variable is introduced, necessitating a 2D shooting. The validation is carried out through comparisons with existing experimental data. Good predictions of the load-slip curves, for different strengthening configurations (extrados and intrados with two curvature radii), are observed. In addition, an insight into local stress distributions and material degradation for matrix layers and interfaces is obtained.