Matrix Integrity Research Articles

On zeros and spectral property of self-affine measures

In this paper, we study the spectral property of self-affine measures generated by an expanding integer matrix and a finite digit set , i.e. investigate whether the function in has a Fourier expansion. Let and for some integer . Through the discussion of the relationships between and , we establish some criteria to determine whether is spectral or non-spectral. Indeed, under those suitable assumptions, if is a spectral measure, we find its spectrum; otherwise, we give the maximum number of orthogonal exponential functions in . As an application, our results can contain some well-known conclusions.

Incompletely Decellularized Tracheal Matrix Scaffold for Tissue Engineering.

Dense cartilaginous extracellular matrix makes decellularization and repopulation of tracheal cartilage difficult. However, the dense matrix isolates cartilaginous antigens from the recipient's immune system. Therefore, allorejection may be avoided by removing antigens from noncartilaginous tissues. In this study, incompletely decellularized tracheal matrix scaffolds were developed for tracheal tissue engineering. Brown Norway rat tracheae were decellularized with 4% sodium deoxycholate treatment. The cell and antigen removal efficacy, histoarchitecture, surface ultrastructure, glycosaminoglycan, collagen contents, mechanical properties, and chondrocyte viability of the scaffold were evaluated in vitro. Brown Norway rat tracheal matrix scaffolds ( n = 6) were implanted subcutaneously into Lewis rats and observed for 4 weeks. Brown Norway rat tracheae ( n = 6) and Lewis rat scaffolds ( n = 6) were implanted as controls. Histologic analysis of macrophage and lymphocyte infiltration was performed. One decellularization cycle removed all cells and antigens from noncartilaginous tissue. Incomplete decellularization preserved the structural integrity of the tracheal matrix and chondrocyte viability. Except for 31% glycosaminoglycan loss, the scaffold had comparable collagen content and tensile and compressive mechanical properties to those of the native trachea. The allogeneic scaffold showed remarkably reduced CD68 + , CD8 + , and CD4 + cell infiltration compared with the allografts and demonstrated similar cell infiltration to the syngeneic scaffold. It also maintained the three-dimensional tracheal structure and cartilage viability in vivo. Incompletely decellularized trachea did not induce immunorejection and maintained the integrity and viability of cartilage in vivo. Tracheal decellularization and repopulation can be simplified for urgent tracheal replacement. The present study describes the development of an incomplete decellularization protocol that creates a decellularized matrix scaffold for tracheal tissue engineering, aiming to provide preliminary data that this method may generate suitable tracheal scaffolds for use in tracheal replacement.

Acetyl Zingerone: A Photostable Multifunctional Skincare Ingredient That Combats Features of Intrinsic and Extrinsic Skin Aging.

The cumulative damage skin sustains from exposure to environmental stressors throughout life exerts significant effects on skin aging and cancer development. One of the main ways by which environmental stressors mediate their effects within skin is through induction of reactive oxygen species (ROS). In this review, we chronicle the multiple properties by which acetyl zingerone (AZ) as a skincare ingredient can benefit skin (1) by helping manage overproduction of ROS through multiple routes as an antioxidant, physical quencher and selective chelator, (2) by fortifying protection after UV exposure ends to prevent the type of epidermal DNA damage that correlates with development of skin cancer, (3) by modulating matrisome activity and nurturing the integrity of the extracellular matrix (ECM) within the dermis and (4) through its proficient ability to neutralize singlet oxygen, by stabilizing the ascorbic acid precursor tetrahexyldecyl ascorbate (THDC) in the dermal microenvironment. This activity improves THDC bioavailability and may blunt pro-inflammatory effects of THDC, such as activation of type I interferon signaling. Moreover, AZ is photostable and can sustain its properties during UV exposure, in contrast to α-tocopherol. All these properties of AZ translate into measurable clinical benefits to improve the visual appearance of photoaged facial skin and to strengthen the skin's own defenses against sun damage.

Time-Dependent Demineralization of Tilapia (Oreochromis niloticus) Bones Using Hydrochloric Acid for Extracellular Matrix Extraction.

Tilapia (Oreochromis niloticus) is a widely cultivated fish in tropical and subtropical regions such as the Philippines, generating substantial waste during processing, including bones that are a valuable source of extracellular matrix (ECM). However, the extraction of ECM from fish bones requires an essential step of demineralization. This study aimed to assess the efficiency of tilapia bone demineralization using 0.5 N HCl at different time durations. By evaluating the residual calcium concentration, reaction kinetics, protein content, and extracellular matrix (ECM) integrity through histological analysis, composition assessment, and thermal analysis, the effectiveness of the process was determined. Results revealed that after 1 h of demineralization, the calcium and protein contents were 1.10 ± 0.12% and 88.7 ± 0.58 μg/mL, respectively. The study found that after 6 h, the calcium content was almost completely removed, but the protein content was only 51.7 ± 1.52 μg/mL compared to 109.0 ± 1.0 μg/mL in native bone tissue. Additionally, the demineralization reaction followed second-order kinetics with an R2 value of 0.9964. Histological analysis using H&E staining revealed a gradual disappearance of the basophilic components and the emergence of lacunae, which can be attributed to decellularization and mineral content removal, respectively. As a result, organic components such as collagen remained in the bone samples. ATR-FTIR analysis showed that all demineralized bone samples retained collagen type I markers, including amide I, II, and III, amides A and B, and symmetric and antisymmetric CH2 bands. These findings provide a route for developing an effective demineralization protocol to extract high-quality ECM from fish bones, which could have important nutraceutical and biomedical applications.

On the maximal number of columns of a Δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta $$\\end{document}-modular integer matrix: bounds and computations

We study the maximal number of pairwise distinct columns in a Δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varDelta $$\\end{document}-modular integer matrix with m rows. Recent results by Lee et al. provide an asymptotically tight upper bound of Om2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {O}\\left( m^2\\right) $$\\end{document} for fixed Δ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varDelta $$\\end{document}. We complement this and obtain an upper bound of the form O(Δ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal {O}(\\varDelta )$$\\end{document} for fixed m, and with the implied constant depending polynomially on m.

Alteration in Mechanical Compliance via Mast Cell Activation in Juvenile and Adult Urinary Bladder

Balance between bladder wall stiffness and mechanical compliance is essential to maintain normal bladder function. These biomechanical properties are directly influenced by the integrity of the extracellular matrix (ECM) and its interaction with urinary bladder smooth muscle (UBSM). While it is clear that normal storage and voiding functions differ between juveniles and adults, it is unclear if these differences are due solely to increases in bladder size. Differences in the mechanical properties of the wall may also exist and are unexplored. Changes in mechanical compliance are implicated in the pathophysiology of many lower urinary tract symptoms (LUTS) such as overactivity and fibrosis due to inflammation. Interestingly, juvenile bladders are particularly susceptible to inflammatory LUTS by various factors (e.g., early life stress) compared to their adult counterparts. We were interested in how bladders from juvenile and adult mice respond to inflammation, specifically driven by mast cell degranulation. We hypothesized that: (1) juvenile bladders are inherently more compliant than adult bladders and (2) mast cell degranulation increases mechanical compliance in both juvenile and adult mouse bladders.Whole mouse bladders from juvenile (4–5 weeks old) and adult (12–14 weeks old) C57Bl/6 male mice were dissected and mounted in a custom designed pentaplanar reflected image macroscopy (PRIM) system for simultaneous measurement of transient pressure events, intravesical pressure, bladder volume, wall stress, and wall stretch during ex vivo bladder filling. Mechanical properties of the bladder wall were measured as the relationship between mechanical stress versus stretch. Properties of the transient contractions were calculated using acquired pressure-volume curves. Measurements were performed in the absence or presence of the mast cell activator Compound 48/80 (10 μg/mL).In the absence of Compound 48/80, the average stress-stretch curves had no significant shift for adult mice compared to young mice, implying no changes in mechanical compliance. However, the mechanical stress in adult mouse bladders was higher compared to juvenile bladders, implying that adult bladders were stiffer. In presence of Compound 48/80, both age groups show similar effects. Mechanical compliance increased with a paradoxical increase in amplitude of transient contractions. Together, these data suggest that while juvenile mouse bladders are less stiff, they respond to mast cell activation in a similar manner as adult bladders. Consequently, rapid degranulation of mast cells in juvenile bladders leads to increased mechanical compliance and contractility. Thus, preventing mast cell degranulation could represent a viable target for treating LUTS in children as well as adults. R01-DK119615 (NRT) and P20-DK127554 (SR and NRT) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

SYMMETRICAL MATRICES CHARACTERISTIC OF INTEGERS WITH INTEGER EIGEN VALUE

Estes (1992) stated that the set of eigen values from symmetrical matrices of Z is a set of totally real algebraic integers. Estes was not able to ensure that eigen values of a symmetrical matrices are integers. Mckee and Smyth (2007) observed more about the eigen value of symmetrical integer matrices. James and Chris proved that symmetrical integer matrices have eigen value with interval ranging in [-2,2]. Contrary to that, Martin and Wong (2009), stated that almost all integer matrices have no integer eigen value. Previous studies that could not show the characteristic of the eigen value made Cao and Koyunco studied and tried to determine the characteristic of symmetrical integer matrices for rank 2 and rank 3. The result shows that they have integer eigen value. In accordance to Cao and Kuyonco study, this article elaborates the characteristic of a symmetrical integer matrices for rank 4, and 5 to show the characteristic of a symmetrical integer matrices with integer eigen value for rank 1, 2, 3 and for rank 4 and 5.

Flue gas carbonation curing of steel slag blocks: Effects of residual heat and water vapor

To make full use of residual heat (temperature) and water vapor (relative humidity, RH) retained in flue gas, the compound effects of temperature (60–140 °C) and RH (2–60 %) of 2-hour CO2 curing on the compressive strength and CO2 fixation of basic oxygen furnace slag (BOFS) blocks were systematically investigated. The results indicated that, in general, an increase of curing temperature increased the compressive strength of the blocks. The high early compressive strength gain (31.3 MPa) at 2-hour for carbonated BOFS blocks was directly related to the microstructure densification and pore refinement due to rich formation of calcite. It should be noted that the supply of sufficient water vapor (≥40 % RH) is particularly important at high temperature (e.g. ≥ 120 °C) to offset the water loss due to water evaporation. Furthermore, under an extremely dry environment (2 % RH), the continuous flow-through of CO2 gas at high temperature not only resulted in no carbonation reaction at the outer layer of the freshly pressed blocks, but may also deteriorate the integrity of the pore structure matrix.

The Ebola virus VP40 matrix layer undergoes endosomal disassembly essential for membrane fusion

Ebola viruses (EBOVs) assemble into filamentous virions, whose shape and stability are determined by the matrix viral protein 40 (VP40). Virus entry into host cells occurs via membrane fusion in late endosomes; however, the mechanism of how the remarkably long virions undergo uncoating, including virion disassembly and nucleocapsid release into the cytosol, remains unknown. Here, we investigate the structural architecture of EBOVs entering host cells and discover that the VP40 matrix disassembles prior to membrane fusion. We reveal that VP40 disassembly is caused by the weakening of VP40–lipid interactions driven by low endosomal pH that equilibrates passively across the viral envelope without a dedicated ion channel. We further show that viral membrane fusion depends on VP40 matrix integrity, and its disassembly reduces the energy barrier for fusion stalk formation. Thus, pH‐driven structural remodeling of the VP40 matrix acts as a molecular switch coupling viral matrix uncoating to membrane fusion during EBOV entry.

Balancing permuted copies of multigraphs and integer matrices

Given a square matrix A over the integers, we consider the Z-module MA generated by the set of all matrices that are permutation-similar to A. Motivated by analogous problems on signed graph decompositions and block designs, we are interested in the completely symmetric matrices aI+bJ belonging to MA. We give a relatively fast method to compute a generator for such matrices, avoiding the need for a very large canonical form over Z. Several special cases are considered. In particular, the problem for symmetric matrices answers a question of Cameron and Cioabǎ on determining the eventual period for integers λ such that the λ-fold complete graph λKn has an edge-decomposition into a given (multi)graph.

Bioengineered tissue and cell therapy products are efficiently cryopreserved with pathogen-inactivated human platelet lysate-based solutions

BackgroundThere remains much interest in improving cryopreservation techniques for advanced therapy medicinal products (ATMPs). Recently, human platelet lysate (hPL) has emerged as a promising candidate to replace fetal bovine serum (FBS) as a xeno-free culture supplement for the expansion of human cell therapy products. Whether hPL can also substitute for FBS in cryopreservation procedures remains poorly studied. Here, we evaluated several cryoprotective formulations based on a proprietary hPL for the cryopreservation of bioengineered tissues and cell therapy products.MethodsWe tested different xenogeneic-free, pathogen-inactivated hPL (ihPL)- and non-inactivated-based formulations for cryopreserving bioengineered tissue (cellularized nanostructured fibrin agarose hydrogels (NFAHs)) and common cell therapy products including bone marrow-derived mesenchymal stromal cells (BM-MSCs), human dermal fibroblasts (FBs) and neural stem cells (NSCs). To assess the tissue and cellular properties post-thaw of NFAHs, we analyzed their cell viability, identity and structural and biomechanical properties. Also, we evaluated cell viability, recovery and identity post-thaw in cryopreserved cells. Further properties like immunomodulation, apoptosis and cell proliferation were assessed in certain cell types. Additionally, we examined the stability of the formulated solutions. The formulations are under a bidding process with MD Bioproducts (Zurich, Switzerland) and are proprietary.ResultsAmongst the tissue-specific solutions, Ti5 (low-DMSO and ihPL-based) preserved the viability and the phenotype of embedded cells in NFAHs and preserved the matrix integrity and biomechanical properties similar to those of the standard cryopreservation solution (70% DMEM + 20% FBS + 10% DMSO). All solutions were stable at − 20 °C for at least 3 months. Regarding cell-specific solutions, CeA maintained the viability of all cell types > 80%, preserved the immunomodulatory properties of BM-MSCs and promoted good recovery post-thaw. Besides, both tested solutions were stable at − 20 °C for 18 months. Finally, we established that there is a 3-h window in which thawed NFAHs and FBs maintain optimum viability immersed in the formulated solutions and at least 2 h for BM-MSCs.ConclusionsOur results show that pathogen-inactivated solutions Ti5 allocated for bioengineered tissues and CeA allocated for cells are efficient and safe candidates to cryopreserve ATMPs and offer a xenogeneic-free and low-DMSO alternative to commercially available cryoprotective solutions.

The shrinking target problem for matrix transformations of tori: Revisiting the standard problem

Let T be a d×d matrix with real coefficients. Then T determines a self-map of the d-dimensional torus Td=Rd/Zd. Let {En}n∈N be a sequence of subsets of Td and let W(T,{En}) be the set of points x∈Td such that Tn(x)∈En for infinitely many n∈N. For a large class of subsets (namely, those satisfying the so called bounded property (B) which includes balls, rectangles, and hyperboloids) we show that the d-dimensional Lebesgue measure of the shrinking target set W(T,{En}) is zero (resp. one) if a natural volume sum converges (resp. diverges). In fact, we prove a quantitative form of this zero-one criteria that describes the asymptotic behaviour of the counting function R(x,N):=#{1≤n≤N:Tn(x)∈En}. The counting result makes use of a general quantitative statement that holds for a large class measure-preserving dynamical systems (namely, those satisfying the so called summable-mixing property). We next turn our attention to the Hausdorff dimension of W(T,{En}). In the case the subsets En are balls, rectangles or hyperboloids we obtain precise formulae for the dimension. These shapes correspond, respectively, to the simultaneous, weighted and multiplicative theories of classical Diophantine approximation. The dimension results for balls generalises those obtained in [25] for integer matrices to real matrices. In the final section, we discuss various problems that stem from the results proved in the paper.

Characterizing Osteochondral Allograft Biomechanics for Optimizing Transplant Success: A Systematic Review.

Osteochondral allograft (OCA) transplantation has been largely successful in treating symptomatic articular cartilage lesions; however, treatment failures persist. While OCA biomechanics have been consistently cited as mechanisms of treatment failure, the relationships among mechanical and biological variables that contribute to success after OCA transplantation have yet to be fully characterized. The purpose of this systematic review was to synthesize the clinically relevant peer-reviewed evidence targeting the biomechanics of OCAs and the impact on graft integration and functional survival toward developing and implementing strategies for improving patient outcomes. The Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, MEDLINE, PubMed, Cumulative Index to Nursing and Allied Health (CINAHL), Google Scholar, and EMBASE were searched to identify articles for systematic review. This review of relevant peer-reviewed literature provided evidence that the biomechanics related to OCA transplantation in the knee have direct and indirect effects on functional graft survival and patient outcomes. The evidence suggests that biomechanical variables can be optimized further to enhance benefits and mitigate detrimental effects. Each of these modifiable variables should be considered regarding indications, patient selection criteria, graft preservation methodology, graft preparation, transplantation, fixation techniques, and prescribed postoperative restriction and rehabilitation protocols. Criteria, methods, techniques, and protocols should target OCA quality (chondrocyte viability, extracellular matrix integrity, material properties), favorable patient and joint characteristics, rigid fixation with protected loading, and innovative ways to foster rapid and complete OCA cartilage and bone integration to optimize outcomes for OCA transplant patients.

Endothelial nitric oxide synthase rs1799983 gene polymorphism is associated with the risk of developing intracranial aneurysm.

The intracranial aneurysm (IA) rupture is associated with a subarachnoid hemorrhage. One third of patients die, and one third remain depend for daily activities. Genetic factors are crucial in the formation and clinical evolution of IAs. Multiple loci have been associated with AIs, much of them implicating multiple pathways related to vascular endothelial maintenance and extracellular matrix integrity. Thus, the aim of our study was to characterize whether polymorphisms in genes implicated in the vascular endothelial maintenance could modify the risk of developing IAs. We have studied 176 patients with IA recruited in the Service of Neurosurgery at the University Hospital of Valladolid (Spain) and a control group if 150 sex-matched healthy subjects. Clinical variables were collected from each patient. We have analyzed VEGFA rs833061, VEGFR2 rs2071559, endothelin rs5370, endoglin rs3739817, and eNOS rs1799983 polymorphisms. Our results showed that allele T of the eNOS rs1799983 polymorphism is correlated with decreased risk of developing the disease; thus, allele G of the eNOS rs1799983 polymorphism increased the risk of developing IA. The association of eNOS rs1799983 polymorphism with the risk to suffer IA reinforces the hypothesis that genetic variants in eNOS gene could be crucial in the pathogenesis of IA.

Preparation, Characterization and Evaluation of Flavonolignan Silymarin Effervescent Floating Matrix Tablets for Enhanced Oral Bioavailability.

The convenient and highly compliant route for the delivery of active pharmaceutical ingredients is the tablet. A versatile platform of tablets is available for the delivery of therapeutic agents to the gastrointestinal tract. This study aimed to prepare gastro retentive drug delivery floating tablets of silymarin to improve its oral bioavailability and solubility. Hydroxypropyl methylcellulose (HPMCK4M and HPMCK15), Carbopol 934p and sodium bicarbonate were used as a matrix, floating enhancer and gas generating agent, respectively. The prepared tablets were evaluated for physicochemical parameters such as hardness, weight variation, friability, floating properties (floating lag time, total floating time), drug content, stability study, in vitro drug release, in vivo floating behavior and in vivo pharmacokinetics. The drug-polymer interaction was studied by Differential Scanning Calorimetry (DSC) thermal analysis and Fourier transform infrared (FTIR). The floating lag time of the formulation was within the prescribed limit (<2 min). The formulation showed good matrix integrity and retarded the release of drug for >12 h. The dissolution can be described by zero-order kinetics (r2 = 0.979), with anomalous diffusion as the release mechanism (n = 0.65). An in vivo pharmacokinetic study showed that Cmax and AUC were increased by up to two times in comparison with the conventional dosage form. An in vivo imaging study showed that the tablet was present in the stomach for 12 h. It can be concluded from this study that the combined matrix system containing hydrophobic and hydrophilic polymers min imized the burst release of the drug from the tablet and achieved a drug release by zero-order kinetics, which is practically difficult with only a hydrophilic matrix. An in vivo pharmacokinetic study elaborated that the bioavailability and solubility of silymarin were improved with an increased mean residence time.

Voluntary exercise modulates pathways associated with amelioration of retinal degenerative diseases.

Background: Exercise has been shown to promote a healthier and longer life and linked to a reduced risk of developing neurodegenerative diseases including retinal degenerations. However, the molecular pathways underpinning exercise-induced cellular protection are not well understood. In this work we aim to profile the molecular changes underlying exercise-induced retinal protection and investigate how exercise-induced inflammatory pathway modulation may slow the progression of retinal degenerations. Methods: Female C57Bl/6J mice at 6weeks old were given free access to open voluntary running wheels for a period of 28days and then subjected to 5days of photo-oxidative damage (PD)-induced retinal degeneration. Following, retinal function (electroretinography; ERG), morphology (optical coherence tomography; OCT) and measures of cell death (TUNEL) and inflammation (IBA1) were analysed and compared to sedentary controls. To decipher global gene expression changes as a result of voluntary exercise, RNA sequencing and pathway and modular gene co-expression analyses were performed on retinal lysates of exercised and sedentary mice that were subjected to PD, as well as healthy dim-reared controls. Results: Following 5days of PD, exercised mice had significantly preserved retinal function, integrity and reduced levels of retinal cell death and inflammation, compared to sedentary controls. In response to voluntary exercise, inflammatory and extracellular matrix integrity pathways were significantly modulated, with the gene expression profile of exercised mice more closely trending towards that of a healthy dim-reared retina. Conclusion: We suggest that voluntary exercise may mediate retinal protection by influencing key pathways involved in regulating retinal health and shifting the transcriptomic profile to a healthy phenotype.

Effect of Flame Treatment on Bonding Performance of GF/EP Pultrusion Sheets Used for VARI Process

This paper presents an easy and low-cost flame treatment method to improve the bonding performance of GF/EP (Glass Fiber-Reinforced Epoxy) pultrusion plates, which are using widely for large size wind blades. In order to explore the effect of flame treatment on the bonding performance of the precast GF/EP pultruded sheet vs. the infusion plate, the GF/EP pultruded sheets were treated with different flame treatment cycles and were embedded in the fiber fabrics during the vacuum-assisted resin infusion process (VARI). The bonding shear strengths were measured by tensile shear tests. It is found that after 1, 3, 5, and 7 flame treatments, the tensile shear strength between the GF/EP pultrusion plate and infusion plate increased by 8.0%, 13.3%, 22.44%, and -2.1%, respectively. This indicates that the maximum tensile shear strength can be obtained after five times of flame treatment. In addition, DCB and ENF tests were also adopted to characterize the fracture toughness of the bonding interface with the optimal flame treatment. It is found that the optimal treatment gives increments of 21.84% and 78.36% for G I C and G II C, respectively. Finally, the surficial topography of the flame-treated GF/EP pultruded sheets were characterized by optical microscopy, SEM, contact angle test, FTIR, and XPS. The results show that flame treatment plays an impact on the interfacial performance through the combination of physical meshing locking and chemical bonding mechanism. Proper flame treatment would remove the weak boundary layer and mold release agent on the surface of the GF/EP pultruded sheet, etch the bonding surface and improve the oxygen-containing polar groups, such as C-O and O-C=O, to improve the surface roughness and surface tension coefficient of pultruded sheet to enhance the bonding performance. Excessive flame treatment destroys the integrity of epoxy matrix on bonding surface which results into the exposure of the glass fiber, and the carbonization of release agent and resin on the surface loosen the surficial structure, which reduces the bonding properties.

A flexible and visually meaningful multi-image compression, encryption and hiding scheme based on 2D compressive sensing

Background: Encrypting plain images into noise-like cipher images is a common method in image encryption. However, when noise-like images appear in public networks, they are more likely to attract attention and suffer more cryptanalysis. To solve this problem, researchers propose the concept of visually meaningful image encryption scheme, which encrypts a plain image into a visually meaningful cipher image. Objective: In order to realize the visual security of cipher image and increase information capacity, this paper proposes a flexible visually secure multi-image compression, encryption and hiding scheme based on two-dimensional compressive sensing (2DCS), which can flexibly complete the compression and encryption of multiple plain images without increasing the amount of ciphertext data. Methods: The scheme is divided into encryption process and embedding process. In the encryption process, the plain image is randomly scrambled and non-linear gray value transformed to obtain a pre-encrypted integer matrix, then 2DCS is used to compress the pre-encrypted integer matrix to get the secret image. Repeat this process for multiple plain images to obtain multiple secret images. In the embedding process, integer wavelet transform and bit-plane decomposition are used to embed multiple secret images into the quantized coefficient matrix of host image to get the modified coefficient matrix, and then the inverse integer wavelet transform is used to transform the modified coefficient matrix into spatial space to get the visually meaningful cipher image. Result: The simulation experiment verifies the feasibility and effectiveness of the visually meaningful multi-image encryption scheme, and users can choose to improve the system's encryption capacity or cipher image's visual security according to their own needs.

Incremental Interval Assignment by Integer Linear Algebra with Improvements

Interval Assignment (IA) is the problem of selecting the number of mesh edges (intervals) for each curve for conforming quad and hex meshing. The intervals x is fundamentally integer-valued. Many other approaches perform numerical optimization then convert a floating-point solution into an integer solution, which is slow and error prone. We avoid such steps: we start integer, and stay integer. Incremental Interval Assignment (IIA) uses integer linear algebra (Hermite normal form) to find an initial solution to the meshing constraints, satisfying the integer matrix equation Ax=b. Solving for reduced row echelon form provides integer vectors spanning the nullspace of A. We add vectors from the nullspace to improve the initial solution, maintaining Ax=b. Heuristics find good integer linear combinations of nullspace vectors that provide strict improvement towards variable bounds or goals. IIA always produces an integer solution if one exists. In practice we usually achieve solutions close to the user goals, but there is no guarantee that the solution is optimal, nor even satisfies variable bounds, e.g. has positive intervals. We describe several algorithmic changes since first publication that tend to improve the final solution. The software is freely available.

Chondroitin Sulfate-Tyramine-Based Hydrogels for Cartilage Tissue Repair.

The degradation of cartilage, due to trauma, mechanical load or diseases, results in abundant loss of extracellular matrix (ECM) integrity and development of osteoarthritis (OA). Chondroitin sulfate (CS) is a member of the highly sulfated glycosaminoglycans (GAGs) and a primary component of cartilage tissue ECM. In this study, we aimed to investigate the effect of mechanical load on the chondrogenic differentiation of bone marrow mesenchymal stem cells (BM-MCSs) encapsulated into CS-tyramine-gelatin (CS-Tyr/Gel) hydrogel in order to evaluate the suitability of this composite for OA cartilage regeneration studies in vitro. The CS-Tyr/Gel/BM-MSCs composite showed excellent biointegration on cartilage explants. The applied mild mechanical load stimulated the chondrogenic differentiation of BM-MSCs in CS-Tyr/Gel hydrogel (immunohistochemical collagen II staining). However, the stronger mechanical load had a negative effect on the human OA cartilage explants evaluated by the higher release of ECM components, such as the cartilage oligomeric matrix protein (COMP) and GAGs, compared to the not-compressed explants. Finally, the application of the CS-Tyr/Gel/BM-MSCs composite on the top of the OA cartilage explants decreased the release of COMP and GAGs from the cartilage explants. Data suggest that the CS-Tyr/Gel/BM-MSCs composite can protect the OA cartilage explants from the damaging effects of external mechanical stimuli. Therefore, it can be used for investigation of OA cartilage regenerative potential and mechanisms under the mechanical load in vitro with further perspectives of therapeutic application in vivo.