Matrix Degradation Research Articles

Screening of Different Fungi Strains Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 for Degradation of Low-Density Polyethylene

Over the past decade, polyethylene (PE) products have become increasingly important in several industries. Their biggest concerns are plastic material degradation resistance and environmental longevity. Therefore, this study aims to find fungi that are capable of degrading low-density polyethylene (LDPE) efficiently. This study uses Gongronella sp. WICC F60, and Cordyceps sp., WICC F61. The fungi were grown on potato dextrose agar for 30 days. Following that, fungal colonies were placed in potato dextrose broth for incubation. The LDPE sample was then cultured with the fungal strain in a minimum salt medium with a 10% inoculum. After 30 days of biodegradation testing, the analysis was done. These studies measured LDPE sample weight loss, pH, and fungal biomass. It was observed that the LDPE sample weight loss increased with time until the end of inclubation. Gongronella sp. WICC F60 and Cordyceps sp. WICC F61 were able to degrade LDPE plastic. Both fungi show an increase in LDPE weight loss. However, Cordyceps sp. WICC F61 shows more efficiency in LDPE degradation compared to Gongronella sp. WICC F60. The LDPE weight loss using Gongronella sp. WICC F60 was 1.07%, which is lower than Gongronella sp. WICC F60's LDPE weight reduction of 5.56%.

Optimizing Nitrogen Fertilization for Enhanced Rice Straw Degradation and Oilseed Rape Yield in Challenging Winter Conditions: Insights from Southwest China

The crop straw returning to the field is a widely accepted method to utilize and remediate huge agricultural waste in a short period. However, the low temperatures and dry conditions of the winter season in Southwest China can be challenging for the biodegradation of crop straw in the field. With a similar aim, we designed a short-term study where rice straw was applied to the field with different concentrations of nitrogen (N) fertilizer while keeping phosphorus (P) constant; CK, (N0P0); T1, (N0P90); T2, (N60P90); T3, (N120P90); and T4, (N180P90) were added to evaluate its impact on straw degradation during cold weather. We found that high fertilization (T4) significantly improved crop yield, organic matter, and lignocellulose degradation under cold temperatures (21.5–3.2 °C). It also significantly improved soil nitrogen agronomic efficiency, nitrogen use efficiency, and nitrogen physiological efficiency. The yield was highest in T4 (1690 and 1399 kg/ha), while T3 acted positively on soil lignocellulolytic enzyme activity, which in turn resulted in higher degradation of OM and lignocellulosic material. Pearson’s correlation analysis revealed that total nitrogen, total phosphorus, available nitrogen, and available phosphorus were important variables that had a significant impact on soil EC, bulk density, water holding capacity, and soil enzymes. We found that nitrogen application significantly changed the soil bacterial community by increasing the richness and evenness of lignocellulolytic bacteria, which aided the degradation of straw in a short duration. This study’s finding indicates that the decomposition of crop straw in the field under cold weather stress was dependent on nutrient input, and N, in an appropriate amount (N120-180), was suitable to achieve higher yield and higher decomposition of straw in such an environment.

Development of a 3D Digital Model of End-of-Service-Life Buildings for Improved Demolition Waste Management through Automated Demolition Waste Audit

This paper presents the development of a 3D digital model of end-of-service-life buildings to facilitate a step change in preparation of pre-demolition protocols that can eliminate problems of inadequate documentation and extensive time spent in preparing pre-demolition audits. The 3D digital model consists of the following four main components: (i) digitization of paper-based drawings and their conversion to CAD; (ii) automated generation of a 3D digital model from CAD; (iii) corrections to the 3D digital model to account for changes in the lifetime of a building; (iv) a sub-model for performing pre-demolition audit. This paper proposes the innovative approaches of incorporating a minimal amount of human intervention to overcome numerous difficulties in automated drawing analysis, application of augmented reality (AR) in corrections to the 3D digital model, and data compatibility for pre-demolition audit. These processes are demonstrated using one building as case study. Using the digital model, a pre-demolition audit can be prepared in minutes rather than the many days required in current practice without a digital model. The accurate quantification of the quantities and locations of different demolition waste materials and products in buildings to be demolished will enable a systematic and quantitative evaluation of potentials of material and product reuse and eliminate contamination of different demolition waste streams (which may contain hazardous waste), which is the main cause of environmental degradation and downcycling of demolition waste materials.

Preparation of double S-scheme NaBiO3/BiO2-x/Bi2O2CO3 heterojunction and the enhancement mechanism of full-spectrum driven degradation activity toward antibiotics

In this work, a series of NaBiO3/BiO2-x/Bi2O2CO3 heterojunction was synthesized via a UV light-assisted chemical precipitation method. Full-solar-spectrum absorption was achieved owing to the localized surface plasmon effect induced by the presence of oxygen vacancies. Furthermore, through the synergistic effect of built-in electric fields and band bending in the interfaces, a Ⅱ-Ⅱ-type structure was successfully transformed into a double S-scheme heterojunction. Consequently, both the separation efficiency and redox ability of photogenerated carriers were simultaneously enhanced, significantly improving the full-solar-spectrum driven photocatalytic performance. Under visible and near-infrared light irradiation, the degradation rates of ofloxacin by the optimal heterojunction could reach 0.1265 min−1 and 0.0075 min−1, respectively, which were 7.27 and 3.95 times higher than those of the one-component NaBiO3. This work provides an efficient strategy for the design and preparation of high-active full-spectrum responsive heterojunction photocatalytic materials for antibiotic degradation.

Tetrazine-based dynamic covalent polymers as degradable extraction materials in sample preparation

BackgroundCurrent trends in Analytical Chemistry are highly focused on the introduction of new extraction materials with a high selectivity towards the target analytes, high extraction capacity as well as sustainable characteristics. In this context, the introduction of smart materials able to respond to an external stimulus constitutes a promising approach in the field. However, investigations regarding the development of such stimuli-responsive polymers have been basically centered on their synthesis and the control of their properties, and hardly on exploiting such properties to generate polymers that, once their extraction function is fulfilled, they can be degraded into fragments with little or negligible toxicity, or even into their constituent monomers for an efficient recycling. ResultsThe applicability of a degradable and recyclable dynamic covalent polymer based on the use of tetrazine as a linker was assessed as sorbent for the extraction of a group of 37 persistent organic pollutants, including 10 polycyclic aromatic hydrocarbons, 11 organochlorine pesticides, 14 polychlorinated biphenyls, and 2 antibacterial agents, from water samples. A microdispersive solid-phase extraction procedure was developed for the selective extraction of the target analytes, while their separation, determination, and quantification were achieved by gas chromatography coupled to mass spectrometry. The optimized procedure was validated for seawater and wastewater obtaining mean relative recovery values between 72 and 112 % for almost all the analytes, with satisfactory relative standard deviation values (<18 %). After extraction, the polymer could be degraded by adding the amino acid L-tyrosine, being possible a quantitative recovery of the initial functional monomer. SignificanceA responsive polymer based on the chemical versatility of the tetrazine ring was used as sorbent in sample preparation providing excellent results, showing good physicochemical properties and the ability to be degraded after use. This polymer constitutes an interesting alternative to reduce chemical waste through the recycling of monomers, contributing to the development of more sustainable analytical methodologies.

Co-composting of dewatered sludge and wheat straw with newly isolated Xenophilus azovorans: Carbon dynamics, humification, and driving pathways

Composting is a biological reaction caused by microorganisms. Composting efficiency can be adequately increased by adding biochar and/or by inoculating with exogenous microorganisms. In this study, we looked at four methods for dewatered sludge waste (DSW) and wheat straw (WS) aerobic co-composting: T1 (no additive), T2 (5% biochar), T3 (5% of a newly isolated strain, Xenophilus azovorans (XPA)), and T4 (5% of biochar-immobilized XPA (BCI-XPA)). Throughout the course of the 42-day composting period, we looked into the carbon dynamics, humification, microbial community succession, and modifications to the driving pathways. Compared to T1 and T2, the addition of XPA (T3) and BCI-XPA (T4) extended the thermophilic phase of composting without negatively affecting compost maturation. Notably, T4 exhibited a higher seed germination index (132.14%). Different from T1 and T2 treatments, T3 and T4 treatments increased CO2 and CH4 emissions in the composting process, in which the cumulative CO2 emissions increased by 18.61–47.16%, and T3 and T4 treatments also promoted the formation of humic acid. Moreover, T4 treatment with BCI-XPA addition showed relatively higher activities of urease, polyphenol oxidase, and laccase, as well as a higher diversity of microorganisms compared to other processes. The Functional Annotation of Prokaryotic Taxa (FAPROTAX) analysis showed that microorganisms involved in the carbon cycle dominated the entire composting process in all treatments, with chemoheterotrophy and aerobic chemoheterotrophy being the main pathways of organic materials degradation. Moreover, the presence of XPA accelerated the breakdown of organic materials by catabolism of aromatic compounds and intracellular parasite pathways. On the other hand, the xylanolysis pathway was aided in the conversion of organic materials to dissolved organics by the addition of BCI-XPA. These findings indicate that XPA and BCI-XPA have potential as additives to improve the efficiency of dewatered sludge and wheat straw co-composting.

Role of various influencing parameters on high temperature fretting behaviour of different tribopairs in liquid lead

The increasing interest in liquid metal cooled nuclear reactors provides technical and scientific challenges such as the understanding, prevention, and prediction of the degradation of materials in liquid lead. Critical components include the fuel rods, heat exchanger tubes, and pump impellers. These functional elements are exposed to mechanical loading (up to 40 MPa), high temperatures (450–550 °C), and fluid-induced vibrations (up to 25 Hz). Under such conditions, fretting wear occurs between e.g., the spacer wire and the outer surface of the fuel or heat exchanger tubes. This work is aimed to establish a laboratory-scale fretting wear test setup and develop test methodology to enable systematic material characterisation in liquid metal environments. The results obtained by using the described methodology indicate that adhesive wear is the dominant degradation mechanism, and 316L stainless steel shows a higher coefficient of friction but a lower wear volume/tribolayer volume compared to 100Cr6 bearing steel. These results are in agreement with those reported in open literature and demonstrates the suitability of the presented method for conducting fretting tests and analysis for various materials and contact configurations in liquid lead environment.

TBK1 pharmacological inhibition mitigates osteoarthritis through attenuating inflammation and cellular senescence in chondrocytes

ObjectivesTANK-binding kinase 1 (TBK1) is pivotal in autoimmune and inflammatory diseases, yet its role in osteoarthritis (OA) remains elusive. This study sought to elucidate the effect of the TBK1 inhibitor BX795 on OA and to delineate the underlying mechanism by which it mitigates OA. MethodsInterleukin-1 Beta (IL-1β) was utilized to simulate inflammatory responses and extracellular matrix degradation in vitro. In vivo, OA was induced in 8-week-old mice through destabilization of the medial meniscus surgery. The impact of BX795 on OA was evaluated using histological analysis, X-ray, micro-CT, and the von Frey test. Additionally, Western blot, RT-qPCR, and immunofluorescence assays were conducted to investigate the underlying mechanisms of BX795. ResultsPhosphorylated TBK1 (P-TBK1) levels were found to be elevated in OA knee cartilage of both human and mice. Furthermore, intra-articular injection of BX795 ameliorated cartilage degeneration and alleviated OA-associated pain. BX795 also counteracted the suppression of anabolic processes and the augmentation of catabolic activity, inflammation, and senescence observed in the OA mice. In vitro studies revealed that BX795 reduced P-TBK1 levels and reversed the effects of anabolism inhibition, catabolism promotion, and senescence induction triggered by IL-1β. Mechanistically, BX795 inhibited the IL-1β-induced activation of the cGAS–STING and TLR3–TRIF signaling pathways in chondrocytes. ConclusionsPharmacological inhibition of TBK1 with BX795 protects articular cartilage by inhibiting the activation of the cGAS–STING and TLR3–TRIF signaling pathways. This action attenuates inflammatory responses and cellular senescence, positioning BX795 as a promising therapeutic candidate for OA treatment. The translational potential of this articleThis study furnishes experimental evidence and offers a potential mechanistic explanation supporting the efficacy of BX795 as a promising candidate for OA treatment.

The RNA binding protein IGF2BP2/IMP2 alters the cargo of cancer cell-derived extracellular vesicles supporting tumor-associated macrophages

BackgroundTumor cells release extracellular vesicles (EVs) that contribute to the polarization of macrophages towards tumor-associated macrophages (TAMs). High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. However, there is a lack of understanding of whether IMP2 affects the cargo of cancer cell-derived EVs, thereby modulating macrophage polarization.MethodsEVs were isolated from IMP2-expressing HCT116 parental cells (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells. EVs were characterized according to MISEV guidelines, microRNA cargo was assessed by microRNA-Seq, and the protein cargo was analyzed by proteomics. Primary human monocyte-derived macrophages (HMDMs) were polarized by EVs, and the expression of genes and surface markers was assessed using qPCR and flow cytometry, respectively. Morphological changes of macrophages, as well as the migratory potential of cancer cells, were assessed by the Incucyte® system and macrophage matrix degradation potential by zymography. Changes in the metabolic activity of macrophages were quantified using a Seahorse® analyzer. For in vivo studies, EVs were injected into the yolk sac of zebrafish larvae, and macrophages were isolated by fluorescence-activated cell sorting.ResultsEVs from WT and KO cells had a similar size and concentration and were positive for 25 vesicle markers. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs than KO EVs, while the expression of TNF and IL6 was reduced. A similar pattern was observed in macrophages from zebrafish larvae treated in vivo. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. MicroRNA-Seq revealed a significant difference in the microRNA composition of WT and KO EVs, particularly a high abundance of miR-181a-5p in WT EVs, which was absent in KO EVs. Inhibitors of macropinocytosis and phagocytosis antagonized the delivery of miR-181a-5p into macrophages and the downregulation of the miR-181a-5p target DUSP6. Proteomics data showed differences in protein cargo in KO vs. WT EVs, with the differentially abundant proteins mainly involved in metabolic pathways. WT EV-treated macrophages exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate than KO EV-treated cells.ConclusionOur results show that IMP2 determines the cargo of EVs released by cancer cells, thereby modulating the EVs' actions on macrophages. Expression of IMP2 is linked to the secretion of EVs that polarize macrophages towards a tumor-promoting phenotype.

The Phylogeny and Metabolic Potentials of an Aromatics-Degrading Marivivens Bacterium Isolated from Intertidal Seawater in East China Sea.

Lignocellulosic materials, made up of cellulose, hemicellulose, and lignin, constitute some of the most prevalent types of biopolymers in marine ecosystems. The degree to which marine microorganisms participate in the breakdown of lignin and their impact on the cycling of carbon in the oceans is not well understood. Strain LCG002, a novel Marivivens species isolated from Lu Chao Harbor's intertidal seawater, is distinguished by its ability to metabolize lignin and various aromatic compounds, including benzoate, 3-hydroxybenzoate, 4-hydroxybenzoate and phenylacetate. It also demonstrates a broad range of carbon source utilization, including carbohydrates, amino acids and carboxylates. Furthermore, it can oxidize inorganic gases, such as hydrogen and carbon monoxide, providing alternative energy sources in diverse marine environments. Its diversity of nitrogen metabolism is supported by nitrate/nitrite, urea, ammonium, putrescine transporters, as well as assimilatory nitrate reductase. For sulfur assimilation, it employs various pathways to utilize organic and inorganic substrates, including the SOX system and DSMP utilization. Overall, LCG002's metabolic versatility and genetic profile contribute to its ecological significance in marine environments, particularly in the degradation of lignocellulosic material and aromatic monomers.

Microstructural characterization and electrochemical behaviour of HVOF sprayed WC-Co-Cr coatings on 316L boiler steel stainless steel

Corrosion is the gradual erosion of metal, primarily because of electrochemical attacks especially under gaseous and alkaline conditions owing to the presence of sulphur and Alkali metals may cause rapid material degradation called Hot corrosion and result in untimely failure of components. To improve surface qualities for corrosion applications, the austenitic 316L stainless steel (SS) in this study was coated with Wc-10%Co–4%Cr utilizing the High-velocity oxy-fuel (HVOF) spray method. After the coated sample was heated to 800 °C for an hour, XRD was used to confirm the coating powder's composition. Using the FESEM technique, the microstructure features were examined, and XRD analysis was performed to ascertain the phase and composition of the substrate. Investigations were also conducted on the electrochemical corrosion characteristics that were impacted by the heat treatment after coating. SEM and EDAX technologies were used to characterize the sample and study its microstructure.

Enhancing access to missionary archives: the role of digital libraries and online repositories

Purpose The purpose of the paper is to explore how digital libraries and online repositories enhance access to missionary archives. It investigates how the digitalization of missionary archives fosters the access, searchability, interactivity, dissemination and preservation of the historical and cultural knowledge of missionary documents and legacies. The selected topic stems from a genuine and deeply ingrained desire and interest to explore the digital archiving landscape, majorly in the context of missionary archives. Design/methodology/approach The study relied heavily on the literature review of the most current scholarly articles. Additionally, the study relied on case studies on missionary institutions and churches that rely on technology to digitize missionary archives and online repositories to make them accessible. Generally, reliance on scholarly articles relevant to the topic was an avenue for examining the existing studies and projects affiliated with digitizing and using missionary archives. Findings Missionary archives and records provide a distinct perspective regarding the realities faced by missionaries and indigenous populations. Digital libraries and online repositories are invaluable and instrumental in improving access to missionary archives. They help users overcome physical barriers while supporting the preservation of fragile materials. Additionally, the digitization efforts of various institutions foster the broader dissemination of missionary records. Digital platforms and online repositories foster collaborative research globally in remote settings. Online repositories are instrumental in enhancing access to missionary archives. They achieve this by providing centralized access points to digitalized collections of historical documents, photographs, manuscripts and artifact. Major challenges include substantial costs affiliated with digitization, environmental factors heightening degradation of the original materials and intellectual property dictations and copyright. Originality/value By using scholarly and authoritative sources of information and evidence, the study contributes to the existing literature by providing insights into the instrumentalism of digital libraries and online repositories to enhance access to missionary archives. There should be comprehensive digitization, adherence to preservation standards, commitment to stakeholder engagement and collaborative decision-making.

Preparation and piezoelectric assisted photocatalytic degradation of BaTiO3/SrTiO3 nanocomposites

Piezoelectric materials capable of generating an inherent electric field under strain, exhibit promising applications in in-situ piezocatalysis and enhanced photocatalytic activities. SrTiO3 (STO) is a photocatalytic material, but it faces challenges such as low efficiency in photogenerated carrier separation and transfer, as well as limited reduction and oxidation reactions. To address these issues, this study utilized the piezoelectric properties of tetragonal BaTiO3 (BTO) nanoparticles and the photocatalytic properties of STO to prepare BaTiO3/SrTiO3 composite materials for piezoelectric assisted photocatalytic degradation of dyes. Disperse BTO nanoparticles with different mass ratios in STO spinning solution to produce a suspension, which is electrospun to form BTO-STO-1:x. The optimal degradation performance and catalytic activity of BTO-STO-1:x were determined through testing to identify the best composite material. It provides a robust foundation for underpinning the coupling mechanism between the enhancement of piezoelectricity and photocatalytic effect, offering an efficient pathway for advancing the field of piezoelectric assisted photocatalysis.

Synthesis and photocatalytic mechanism study of visible light-driven Z-type Ag/AgBr/Bi2MoO6 composite materials for efficient degradation of organic dyes

The synthesis of the Ag/AgBr/Bi2MoO6 nanocomposite was achieved through a facile hydrothermal method combined with in situ photodeposition. Subsequently, its efficacy in catalyzing the degradation of Rhodamine B (RhB) under visible light irradiation was systematically investigated. The Bi2MoO6 samples and the Ag/AgBr/Bi2MoO6 nanocomposites underwent comprehensive characterization using a suite of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The analyses unveiled a homogeneous distribution of Ag nanoparticles on the surface of AgBr/Bi2MoO6, indicative of the successful formation of the composite. To assess the photocatalytic efficiency, the degradation of RhB under visible light irradiation was employed as a benchmark. Notably, the incorporation of Ag nanosheets, serving as electron mediators and Schottky barriers, facilitated efficient electron transfer between Bi2MoO6 and AgBr. Consequently, the photocatalytic activity of the ternary Z-type heterogeneous Ag/AgBr/Bi2MoO6 nanocomposites surpassed that of the pure Bi2MoO6 and AgBr samples. Remarkably, under 12 min of visible light irradiation, the photocatalytic activity of the Ag/AgBr/Bi2MoO6 nanocomposites reached an impressive 99.99 %.

Synthesis, characterization and photocatalytic activity of alginate based hybrid material for efficient degradation of organic pollutants under UV light and sunlight irradiation

This study reports the development of alginate based hybrid material (Alg/CuO-gC₃N₄) with copper oxide (CuO) and graphitic carbon nitride (gC₃N₄). The Alg/CuO-gC₃N₄ hydrogel bead was prepared by two step process is as follows: formation of CuO-gC₃N₄ by co-precipitation method and incorporation of CuO-gC₃N₄ in the calcium alginate (Alg) by ionotropic gelation method. The structural and morphological features of the Alg/CuO-gC₃N₄ was characterized using different techniques namely Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), UV Diffuse Reflectance spectroscopy (UV-DRS) and Scanning electron microscopy (SEM). The photocatalytic activity of the Alg/CuO-gC₃N₄ was extensively evaluated by degrading methylene blue (MB) under UV–vis and sunlight irradiation. The influence of various parameters like pollutant type, initial dye concentration, catalyst dosage, effect of pH, light intensity and reusability was investigated. The Alg/CuO-gC₃N₄ achieved a maximum degradation efficiency of 86.26 % and 85.15 % for MB at a dye concentration of 1 × 10−5 M under UV–vis and sunlight irradiation respectively, within 60 min using 0.3 wt% of catalyst dosage. The Alg/CuO-gC₃N₄ exhibited excellent stability and reusability over multiple cycles. Additionally, the incorporation of CuO-gC₃N₄ in alginate facilitates in reducing the bandgap (2.54 to 2.28 eV) for efficient charge separation, further enhancing the overall photocatalytic activity.

Indoor paint life cycle particle release: Safer-by-design products and the importance of choosing the right formula

In 2020, the European Commission published a regulation that states all producers of white paints containing titanium dioxide (TiO2) must provide a warning label on their products. Exposure during the production and application of products containing TiO2 can be harmful, and therefore these products must be labeled as “may cause cancer.” The paint industry is a major user of TiO2 pigment. This study focuses on pigment release from three TiO2-based paints and discusses the effect of paint formulation, more precisely the Pigment Volume Concentration (PVC), to predict TiO2 pigment release from the paints during a simulated use phase and at the end of life (EoL). The use phase considered mild abrasion of painted panels that simulated cleaning or touching. The EoL phase was studied using leaching tests simulating landfill disposal. TiO2 release during both activities was evident with a high discrepancy between the three paints. While dry rubbing was similar for all paints, activities involving water present a high release link to paint matrix degradation. The paint pigment volume concentration and the paint permeability determines the TiO2 release during wet rubbing and leaching. This work represents an attempt to identify the paint permeability as a matrix-related parameter to predict TiO2 release and a way to use of this parameter to develop safer products.

SP1‑mediated ADAMTS5 transcription promotes IL‑1β‑induced chondrocyte injury via Wnt/β‑catenin pathway in osteoarthritis.

Osteoarthritis (OA) is a chronic disease that involves chondrocyte injury. ADAMTS5 has been confirmed to mediate chondrocyte injury and thus regulate OA progression, but its underlying molecular mechanisms remain unclear. In the present study, interleukin‑1β (IL‑1β)‑induced chondrocytes were used to mimic OA in vitro. Cell proliferation and apoptosis were assessed by MTT assay, EdU assay and flow cytometry, and protein levels of ADAMTS5, specificity protein 1 (SP1), matrix‑related markers and Wnt/β‑catenin pathway‑related markers were examined using western blotting. In addition, ELISA was performed to measure the concentrations of inflammation factors, and oxidative stress was evaluated by detecting SOD activity and MDA levels. The mRNA expression levels of ADAMTS5 and SP1 were determined by reverse transcription‑quantitative PCR, and the interaction between SP1 and ADAMTS5 was analyzed using a dual‑luciferase reporter assay and chromatin immunoprecipitation assay. IL‑1β suppressed proliferation, but promoted apoptosis, extracellular matrix degradation, inflammation and oxidative stress in chondrocytes. ADAMTS5 was upregulated in IL‑1β‑induced chondrocytes, and its knockdown alleviated IL‑1β‑induced chondrocyte injury. SP1 could bind to the ADAMTS5 promoter region to promote its transcription, and SP1 knockdown relieved IL‑1β‑induced chondrocyte injury by reducing ADAMTS5 expression. The SP1/ADAMTS5 axis activated the Wnt/β‑catenin pathway, and the Wnt/β‑catenin pathway agonist, SKL2001, reversed the protective effect of ADAMTS5 knockdown on chondrocyte injury induced by IL‑1β. To the best of our knowledge, the present study was the first to reveal the interaction between SP1 and ADAMTS5 in OA progression and indicated that the SP1/ADAMTS5 axis mediates OA progression by regulating the Wnt/β‑catenin pathway.

Molecular Dynamics Simulation of Cumulative Microscopic Damage in a Thermosetting Polymer under Cyclic Loading.

To develop durable composite materials, it is crucial to elucidate the correlation between nanoscale damage in thermosetting resins and the degradation of their mechanical properties. This study aims to investigate this correlation by performing cyclic loading tests on the cross-linked structure of diglycidyl ether bisphenol A (DGEBA) and 4,4'-diaminodiphenyl sulfone (44-DDS) using all-atom molecular dynamics (MD) simulations. To accurately represent the nanoscale damage in MD simulations, a bond dissociation algorithm based on interatomic distance criteria is applied, and three characteristics are used to quantify the microscopic damage: stress-strain curves, entropy generation, and the formation of voids. As a result, the number of covalent bond dissociations increases with both the cyclic loading and its amplitude, resulting in higher entropy generation and void formation, causing the material to exhibit inelastic behavior. Furthermore, our findings indicate the occurrence of a microscopic degradation process in the cross-linked polymer: Initially, covalent bonds align with the direction of the applied load. Subsequently, tensioned covalent bonds sequentially break, resulting in significant void formation. Consequently, the stress-strain curves exhibit nonlinear and inelastic behavior. Although our MD simulations employ straightforward criteria for covalent bond dissociation, they unveil a distinct correlation between the number of bond dissociations and microscale damage. Enhancing the algorithm holds promise for yielding more precise predictions of material degradation processes.

Mantis shrimp appendages-inspired Ag-CuO contact: Synergistically enhancing the erosion and impact resistance via gradient-layered scatter-island/chain-skeleton structure

Materials degradation induced by repeated arc erosion and impact poses a considerable challenge for Ag-based contacts. Fortunately, nature has evolved efficient strategies to construct complex gradient-layered structure that exhibit exceptional erosion and impact resistance. Drawing inspiration by the mantis shrimp appendages, a chain-like CuO nanofibre-reinforced Ag-CuO contact material with a gradient-layered scatter-island/chain-skeleton structure was designed and fabricated. Employing a combined experimental and simulation approach, the evolution of the microstructure during the erosion process was investigated. Results indicated that the interaction between the mantis shrimp appendage-like structure and the chain-like CuO nanofibres effectively suppressed the formation of cracks and pores on the contact surface. Particularly, the scatter-island layer not only played a crucial role in maintaining the viscosity of the molten pool and establishing stable electrical and thermal pathways, but also functioned as a “supplement” to continuously supply a steady source of Ag onto the molten pool surface, effectively promoting CuO skeleton restructuring. Meanwhile, the CuO skeleton diffusive-continuous restructuring of the chain-skeleton layer restricted molten pool flow, significantly enhancing contact erosion resistance. Furthermore, the strong synergistic effect between the gradient-layered structures dispersed stress and deformation concentration on the contact surface. It effectively delayed the defects formation and suppressed interfacial debonding, thereby endowing the contact with excellent impact resistance. Our work presents a fascinated route for designing novel biomimetic Ag-based contacts.

Genome-wide development of simple sequence repeats markers and genetic diversity analysis of chayote

BackgroundChayote is a high economic crop in the Cucurbitaceae family, playing an important role in food production, disease treatment and the production of degradable materials in industries. Due to the harsh environment, such as high temperature, drought and frost, some chayote resources are gradually disappearing. It is crucial to collect, characterize, and conserve chayote resources. However, the genetic diversity of chayote resources in China has not been studied so far.ResultsIn this study, we collected 35 individuals of chayote from 14 provinces in China. Subsequently, we found 363,156 SSR motifs from the chayote genome and designed 57 pairs of SSR primers for validation. Out of these, 48 primer pairs successfully amplified bands, with 42 of them showing polymorphism. These 42 primer pairs detected a total of 153 alleles, averaging 3.64 alleles per locus. The polymorphic information content ranged from 0.03 to 0.78, with an average value of 0.41, indicating a high level of polymorphism. Based on the analysis using STRUCTURE, PCoA, and UPGMA methods, the 35 chayote individuals were divided into two major clusters. Through further association analysis, 7 significantly associated SSR markers were identified, including four related to peel color and three related to spine.ConclusionsThese molecular markers will contribute to the analysis of genetic diversity and genetic breeding improvement of chayote in the future.