Matrix Integrity Research Articles

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.

An Injectable Engineered Cartilage Gel Improves Intervertebral Disc Repair in a Rat Nucleotomy Model.

Lower back pain is a major problem caused by intervertebral disc degeneration. A common surgical procedure is lumbar partial discectomy (excision of the herniated disc causing nerve root compression), which results in further disc degeneration, severe lower back pain, and disability after discectomy. Thus, the development of disc regenerative therapies for patients who require lumbar partial discectomy is crucial. Here, we investigated the effectiveness of an engineered cartilage gel utilizing human fetal cartilage-derived progenitor cells (hFCPCs) on intervertebral disc repair in a rat tail nucleotomy model. Eight-week-old female Sprague-Dawley rats were randomized into three groups to undergo intradiscal injection of (1) cartilage gel, (2) hFCPCs, or (3) decellularized extracellular matrix (ECM) (n = 10/each group). The treatment materials were injected immediately after nucleotomy of the coccygeal discs. The coccygeal discs were removed six weeks after implantation for radiologic and histological analysis. Implantation of the cartilage gel promoted degenerative disc repair compared to hFCPCs or hFCPC-derived ECM by increasing the cellularity and matrix integrity, promoting reconstruction of nucleus pulposus, restoring disc hydration, and downregulating inflammatory cytokines and pain. Our results demonstrate that cartilage gel has higher therapeutic potential than its cellular or ECM component alone, and support further translation to large animal models and human subjects.

Exploring the impact of temperature and oxygen partial pressure on the spent nuclear fuel oxidation during its dry management

The management of Spent Nuclear Fuel (SNF) comprises different stages in which security is demonstrated. Nevertheless, fundamental research can lead to other design options that must be considered. Currently, one of the focuses is the dry interim storage option, as the shortest-term solution until final repositories are available. During this stage, one concern is the oxidation of the fuel. If UO2 (SNF matrix) is exposed to air at high-enough temperature, formation of U3O8 takes place. The larger volume of this phase could entail stresses on the SNF clad, which is the first barrier to prevent radioactive material release. It is known that this oxidation is a temperature-dependent reaction and ensuring an inert atmosphere discards any effect during SNF dry management. However, at what extent temperature and oxygen concentration would have an impact on the U3O8 formation is not established, being the available experimental data very scarce. We follow this oxidation in representative ranges of temperature and oxygen concentration of dry storage facilities by using in-situ Raman spectroscopy. The results show that temperature is a more-affecting factor than the oxygen concentration at the studied conditions. Therefore, efforts to limit temperatures would yield more benefits in preserving fuel matrix integrity.

Power-product matrix: nonsingularity, sparsity and determinant

In this paper, we are interested in a special class of integer matrices, namely the power-product matrix, defined with two positive integers n and d. Each matrix element is computed by a power-product of two weak compositions of d into n parts. The power-product matrix has several interesting applications such as the power-sum representation of polynomials and the difference-of-convex-sums-of-squares decomposition of polynomials. We investigate some properties of this matrix including: nonsingularity, sparsity and determinant. Based on techniques in enumerative combinatorics, we prove that the power-product matrix is nonsingular and the number of nonzero entries can be computed exactly. This matrix shows sparse structure which is a good feature in numerical computation of its inverse required in some applications. Special attention is devoted to the computation of the determinant for n = 2 whose explicit formulation is obtained.

The R ∞ R_{\infty} property for nilpotent quotients of Generalized Solvable Baumslag–Solitar groups

Abstract We say a group 𝐺 has property R ∞ R_{\infty} if the number R ⁢ ( φ ) R(\varphi) of twisted conjugacy classes is infinite for every automorphism 𝜑 of 𝐺. For such groups, the R ∞ R_{\infty} -nilpotency degree is the least integer 𝑐 such that G / γ c + 1 ⁢ ( G ) G/\gamma_{c+1}(G) has property R ∞ R_{\infty} . In this work, we compute the R ∞ R_{\infty} -nilpotency degree of all Generalized Solvable Baumslag–Solitar groups Γ n \Gamma_{n} . Moreover, we compute the lower central series of Γ n \Gamma_{n} , write the nilpotent quotients Γ n , c = Γ n / γ c + 1 ⁢ ( Γ n ) \Gamma_{n,c}=\Gamma_{n}/\gamma_{c+1}(\Gamma_{n}) as semidirect products of finitely generated abelian groups and classify which invertible integer matrices can be extended to automorphisms of Γ n , c \Gamma_{n,c} .

Improved Gentry–Halevi's fully homomorphic encryption‐based lightweight privacy preserving scheme for securing medical Internet of Things

AbstractInternet of Medical Things (IoMT) solutions have proliferated rapidly in the COVID‐19 pandemic era. The smart medical sensors capture real‐time data from remote patients and communicate it to medical servers in a secure and privacy‐preserving manner. It is a herculean challenge to guarantee security and privacy in Medical IoT applications. Hence, an improved Gentry–Halevi's fully homomorphic encryption‐based (IGHFHE) lightweight privacy preserving user authentication scheme is proposed in this work. The scheme is proposed with an integer matrix computation strategy for securing data computation with privacy protection. It adopts the translation process of Gentry–Halevi's fully homomorphic encryption process for performing homomorphic addition and multiplication, then encrypt an integer matrix modulo that represents a positive integer. Extensive informal investigation and simulation of the proposed IGHFHE scheme shows that it is more resistant to well‐known attacks for preventing authentication breaches. Also, the proposed IGHFHE scheme reduced computational and storage overhead by 4.98% and 5.78% respectively on average in comparison to other prevailing schemes.

Aging effects in the extracellular matrix of the clitoris: A scanning electron microscopic analysis

The present work aims to observe the clitoris' extracellular matrix in young and old women with a scanning electron microscope. After approval of the local research ethics committee, samples of the clitoris body were obtained from cadavers of women between 20 and 40 old (G1) and from cadavers over the age of 60 (G2). The samples were decellularized with NaOH to maintain the extracellular matrix framework, submitted to silver sputter coating, and observed under a scanning electron microscope. The mean age of the cadavers in G1 was 28 years old and 75±6 years old in G2. The groups were composed of 10 cadavers each. It was observed that the collagen was arranged in a disorganized fashion in the samples from the G2 in several regions. There was also a decrease in elastic fibers that anchored the collagen in these samples. The concentration of collagen showed an increase in the older samples in comparison to the G1 samples. Conclusions Female sexual dysfunction is a condition prevalent in a significantly large portion of women and it is more common in elderly women. It is known that the tumescence mechanism requires integrity of the extracellular matrix. The changes observed herein may alter the function of the organ and are similar to observations in studies of men with erectile dysfunction. Female sexual dysfunction is a condition prevalent in a significantly large portion of women and it is more common in elderly women. It is known that the tumescence mechanism requires integrity of the extracellular matrix. The changes observed herein may alter the function of the organ and are similar to observations in studies of men with erectile dysfunction. .

Tumor decellularization reveals proteomic and mechanical characteristics of the extracellular matrix of primary liver cancer

Tumor initiation and progression are critically dependent on interaction of cancer cells with their cellular and extracellular microenvironment. Alterations in the composition, integrity, and mechanical properties of the extracellular matrix (ECM) dictate tumor processes including cell proliferation, migration, and invasion. Also in primary liver cancer, consisting of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), the dysregulation of the extracellular environment by liver fibrosis and tumor desmoplasia is pertinent. Yet, the exact changes occurring in liver cancer ECM remain uncharacterized and underlying tumor-promoting mechanisms remain largely unknown. Herein, an integrative molecular and mechanical approach is used to extensively characterize the ECM of HCC and CCA tumors by utilizing an optimized decellularization technique. We identified a myriad of proteins in both tumor and adjacent liver tissue, uncovering distinct malignancy-related ECM signatures. The resolution of this approach unveiled additional ECM-related proteins compared to large liver cancer transcriptomic datasets. The differences in ECM protein composition resulted in divergent mechanical properties on a macro- and micro-scale that are tumor-type specific. Furthermore, the decellularized tumor ECM was employed to create a tumor-specific hydrogel that supports patient-derived tumor organoids, which provides a new avenue for personalized medicine applications. Taken together, this study contributes to a better understanding of alterations to composition, stiffness, and collagen alignment of the tumor ECM that occur during liver cancer development.

Asymptotic Properties of Random Contingency Tables with Uniform Margin

Let $C\geq 2$ be a positive integer. Consider the set of $n\times n$ non-negative integer matrices whose row sums and column sums are all equal to $Cn$ and let $X=(X_{ij})_{1\leq i,j\leq n}$ be uniformly distributed on this set. This $X$ is called the random contingency table with uniform margin. In this paper, we study various asymptotic properties of $X=(X_{ij})_{1\leq i,j\leq n}$ as $n\to\infty$.

Impact of fortificants on the powder properties of a gluten-free porous starch matrix of puffed rice flour

Iron and zinc fortified pulverized expanded porous starch matrix of puffed rice (EPSMPR) flours of different particle sizes (50–150, 150–300, 300–425, 425–500, and 500–710 μm) were analyzed for powder properties and compared with un-fortified EPSMPR flours. Both fortified and control EPSMPR flour samples showed flow stability values close to 1, signifying the integrity of the flour matrix to various flow conditions. At higher rotor speed (up to 100 mm/s), no significant increase in the compaction coefficient was observed for both fortified and control EPSMPR flour of varying particle size, indicating flow speed independency. Increase in caking strength (up to 61%), water absorption capacity (up to 16%), and swelling capacity (up to 20%) of EPSMPR flour was observed with particle size. PCA analysis revealed a negative correlation between tapped and untapped densities and water absorption index: the angle between them was approximately 180°. Similarly, the angle of repose correlated negatively with the caking index.

Reversible De-identification of Specific Regions in Biomedical Images and Secured Storage by Randomized Joint Encryption

In many circumstances, de-identification of a specific region of a biomedical image is necessary. De-identification is used to hide the subject’s identity or to prevent the display of the objectionable or offensive region(s) of the image. The concerned region can be blurred (de-identified) by using a suitable image processing technique guided by the region-defining mask. The proposed method provides lossless blurring, which means the original image can be recovered fully with zero loss. The blurred image and the region-defining mask, along with the digital signature, are jointly encrypted to form the composite cipher matrix, and it is stored in the cloud for further distribution. The composite cipher matrix is decrypted to recover the blurred image by the conventional end user. Further, using the deblur key, the original image can be recovered with zero loss by the fully authorized special end users. On decryption, the digital signature is available for both types of end users. The proposed method uses randomized joint encryption using integer matrix keys in a finite field. The experimental results show that the proposed method achieves a reduction in the average execution time of encryption by 30 to 40 percent compared to its nearest competitor. Additionally, the proposed scheme achieves very nearly ideal performance with reference to the correlation coefficient, entropy, pixel change rate, and structural similarity index. Overall, the proposed algorithm performs substantially better than the other similar existing schemes for large-sized images.

Novel structural feature-descriptor platform for machine learning to accelerate the development of organic photovoltaics

Although the evolution of organic photovoltaics (OPVs) has been remarkable, the discovery of new combinations of materials for ideal bulk heterojunction (BHJ) blend systems remains challenging because of their numerous considerations. Aiming to eliminate the typically labor-intensive trial-and-error approaches, machine learning (ML) models coupled with quantitative structure-property relationships are constructed to efficiently predict the photovoltaic parameters. To this end, a unique structural-feature descriptor that fragments a molecular structure into functional group (FG) units is designed. These units are indexed and the indices are combined to translate the molecular structure into a concise matrix of integers. Our novel descriptor allows the ML models to trace the FGs with ease and assign larger weights to those FGs that significantly contribute to the photovoltaic performance. Furthermore, the descriptor enables the expansion of OPV ML to ternary or multicomponent BHJ systems because of its concise expression. The proposed ML model achieves a high correlation coefficient of 0.86 between experimental and predictive power conversion efficiency of OPVs, despite using only the molecular structure information without any additional input data. Combined with the superior prediction capabilities, our novel approach promises to perfectly screen numerous BHJ cadidates, resulting in accelerating the development of the OPV.

Aberrant claustrum structure in preterm-born neonates: an MRI study

The human claustrum is a gray matter structure in the white matter between insula and striatum. Previous analysis found altered claustrum microstructure in very preterm-born adults associated with lower cognitive performance. As the claustrum development is related to hypoxia–ischemia sensitive transient cell populations being at-risk in premature birth, we hypothesized that claustrum structure is already altered in preterm-born neonates.We studied anatomical and diffusion-weighted MRIs of 83 preterm- and 83 term-born neonates at term-equivalent age. Additionally, claustrum development was analyzed both in a spectrum of 377 term-born neonates and longitudinally in 53 preterm-born subjects. Data was provided by the developing Human Connectome Project.Claustrum development showed increasing volume, increasing fractional anisotropy (FA), and decreasing mean diffusivity (MD) around term both across term- and preterm-born neonates. Relative to term-born ones, preterm-born neonates had (i) increased absolute and relative claustrum volumes, both indicating increased cellular and/or extracellular matter and being in contrast to other subcortical gray matter regions of decreased volumes such as thalamus; (ii) lower claustrum FA and higher claustrum MD, pointing at increased extracellular matrix and impaired axonal integrity; and (iii) aberrant covariance between claustrum FA and MD, respectively, and that of distributed gray matter regions, hinting at relatively altered claustrum microstructure.Results together demonstrate specifically aberrant claustrum structure in preterm-born neonates, suggesting altered claustrum development in prematurity, potentially relevant for later cognitive performance.

The peritrophic matrix delays Nosema ceranae infection in the honey bee Apis mellifera midgut

AbstractThe midgut of bees plays a significant role in digestion and absorption and is a gateway for pathogens. As a protection for the organism, the midgut lumen is lined by a peritrophic matrix rich in chitin fibrils, associated with proteins that form multiple resistant layers with gelatinous consistency, with several functions, including the mechanical barrier against infection by pathogens. The obligate intracellular microsporid Nosema ceranae is an important pathogen that decreases honey production, increases pesticide susceptibility, and may cause mortality in the honey bee Apis mellifera. This study evaluated whether the peritrophic matrix has a protective function against infection by N. ceranae in A. mellifera adult workers. The peritrophic matrix integrity was changed by feeding the bees with calcofluor white (CFW), followed by an artificial infection with N. ceranae spores. Results shown that 0.5% CFW affect the integrity of the peritrophic matrix with areas of interruption of this envelope. This disorganization of the peritrophic matrix reduces the life cycle period of N. ceranae from eight to four days, after inoculation, and increases the concentration of new spores released in the midgut lumen. This is the first report on the importance of the peritrophic matrix as a protective barrier against N. ceranae infection in A. mellifera.

Use of Lightweight Sintered Fly Ash Aggregates in Concrete at High Temperatures

This study addresses the issue of the resistance to high temperatures of lightweight concrete lightweighted with sintered fly ash aggregate. Lightweight concretes with different amounts of lightweighting and their properties after loading temperatures of 600, 800 and 1000 °C were investigated. In particular, the effect of high temperature on the mechanical properties of the concrete was determined on the test specimens, and the effect on the microstructure was investigated by X-ray diffraction analysis and scanning electron microscopy. It was found that there is an increase in compressive strength between 0 and 21% up to 800 °C, where the increase in strength decreases with increasing degree of lightening. At 1000 °C, the internal structure of the lightweight concrete destabilized, and the compressive strength decreased in the range of 51–65%. After loading at 1000 °C, the scanning electron microscope showed the formation of spherical-shaped neoplasms, which significantly reduced the internal integrity of the cement matrix in the lightweight concrete due to the increase in their volume. It was found that the lightweight concretes with higher lightweighting showed significantly less degradation due to higher temperature.

Recent Advances in Proteomics-Based Approaches to Studying Age-Related Macular Degeneration: A Systematic Review.

Age-related macular degeneration (AMD) is a common ocular disease characterized by degeneration of the central area of the retina in the elderly population. Progression and response to treatment are influenced by genetic and non-genetic factors. Proteomics is a powerful tool to study, at the molecular level, the mechanisms underlying the progression of the disease, to identify new therapeutic targets and to establish biomarkers to monitor progression and treatment effectiveness. In this work, we systematically review the use of proteomics-based approaches for the study of the molecular mechanisms underlying the development of AMD, as well as the progression of the disease and on-treatment patient monitoring. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) reporting guidelines were followed. Proteomic approaches have identified key players in the onset of the disease, such as complement components and proteins involved in lipid metabolism and oxidative stress, but also in the progression to advanced stages, including factors related to extracellular matrix integrity and angiogenesis. Although anti-vascular endothelial growth factor (anti-VEGF)-based therapy has been crucial in the treatment of neovascular AMD, it is necessary to deepen our understanding of the underlying disease mechanisms to move forward to next-generation therapies for later-stage forms of this multifactorial disease.

The Jones polynomial from a Goeritz matrix

AbstractWe give an explicit algorithm for calculating the Kauffman bracket of a link diagram from a Goeritz matrix for that link. Further, we show how the Jones polynomial can be recovered from a Goeritz matrix when the corresponding checkerboard surface is orientable, or when more information is known about its Gordon–Litherland form. In the process we develop a theory of Goeritz matrices for cographic matroids, which extends the bracket polynomial to any symmetric integer matrix. We place this work in the context of links in thickened surfaces.