Sample Material Research Articles

АДГЕЗИВНАЯ АКТИВНОСТЬ МИКРООРГАНИЗМОВ К СТОМАТОЛОГИЧЕСКИМ МАТЕРИАЛАМ ДЛЯ 3D ПЕЧАТИ И ВАКУУМНОЙ ФОРМОВКИ

Relevance: The adhesive activity of the oral microbiome to new generation materials is the subject of study by the global medical community, and the issue of choosing structural materials is still being discussed in the scientific community and is of a controversial nature. Objective: To study the adhesion of representatives of the oral microbiome to samples of modern dental materials under experimental conditions (in vitro). Materials and methods: Samples of photopolymer resins for 3D printing: Dental Crown LCD, Dental Sand A1-A2, Dental Clear Pro, (n=30), (1-3 groups), thermoforming plates for vacuum forming: EV Gasket Bleaching 080, Bioplast multicolor 3.0*123 mm, Bioplast color 3.0*125 mm (n=30), (groups 4-6); clinical isolates of the microbiome as test strains: Staphylococcus aureus, Streptococcus oralis, Neisseria subflava, Actinomyces oris, Candida albicans (n=5). Research methods: experimental, microbiological, cultural, analytical and statistical. Results: The degree of adhesion of representatives of the oral microbiome to the studied structural materials is in the range from 0 to 4.91 (Ia) and depends on both the species composition of the microbiome and the physico-chemical properties of the materials. The high adhesion index for all microbiota groups was noted for vacuum forming materials (4.91), and the lowest was Dental Crown LCD (0), which makes it possible to recommend it for practical use. Conclusions: The choice of structural material should be made, including taking into account the adhesive activity of the oral microbiome in order to reduce the risk of complications. It is recommended to give preference to materials with a low adhesive activity index.

Impact Absorption Power of Polyolefin Fused Filament Fabrication 3D-Printed Sports Mouthguards: InVitro Study.

This study aims to evaluate and compare the impact absorption capacities of thermoformed ethylene vinyl acetate (EVA) mouthguards and 3D-printed polyolefin mouthguards used in sports dentistry applications. The objective is to determine whether 3D-printed polyolefin mouthguards offer superior impact toughness compared to traditional EVA mouthguards commonly used in sports settings. Six material samples were assessed: five pressure-formed EVA mouthguards (PolyShok, Buffalo Dental, Erkoflex, Proform, and Drufosoft) and one 3D-printed synthetic polymer (polyolefin). The materials were evaluated using a modified American Society for Testing and Materials (ASTM) D256 Test Method A for Izod pendulum impact resistance of plastics. Polyolefin samples were 3D-printed using fused filament fabrication (FFF) technology. Notably, the FFF process included samples printed with notches placed either parallel or perpendicular to the build direction. This orientation served as a study factor, allowing for comparison of material behavior under different printing conditions. Impact testing was conducted using an Izod impact tester to assess the materials' performance under controlled impact conditions. The study achieved a high power (1.0) in power analysis, indicating strong sensitivity to detect significant differences. Among molded materials, PolyShok showed significantly lower impact toughness compared to others (p = 0.06). The mean impact absorption of EVA materials was 5.4 ± 0.3 kJ/m2, significantly lower than polyolefin materials, which demonstrated 12.9 ± 0.7 kJ/m2 and superior performance (p = 0.0). Horizontal-notched polyolefin samples exhibited higher impact strength compared to vertical-notched samples (p = 0.009). 3D-printed polyolefin mouthguards exhibited significantly higher impact toughness than thermoformed EVA mouthguards. While EVA materials demonstrated structural robustness, their lower impact resistance and observed tearing in other test specimens suggest the need for alternative testing standards to better reflect real-world conditions. 3D-printed mouthguards fabricated with build orientations perpendicular to the direction of impact demonstrate significantly enhanced impact absorption. Further research into manufacturing methods and testing protocols is recommended to optimize mouthguard performance under impact scenarios.

Development of Technology for Providing Antimicrobial Properties to Medical Disposable Masks

Wearing masks to protect against communicable diseases is an effective tool used in many countries affected by the COVID-19 pandemic. The antibacterial activity, antibacterial efficiency, microbial purity, and breathability properties of medical disposable masks are very important. Ag is most commonly applied to antimicrobial textiles. In this work, three antimicrobial additives were used. Four compositions of the binders with antimicrobial additives were prepared and applied to one-layer non-woven PP material. The influence of the binder antimicrobial polymer coating on the breathability and antibacterial activity of the non-woven PP material was evaluated. The results show that the composition of the polyacrylic acid binder had the least effect on their breathability and samples with the silver chloride formulation showed the best antimicrobial response. Based on the microbiological and air permeability results of the samples of the one-layer non-woven material with coating, the samples of two layers and three layers of the medical mask model were prepared. Microbiological studies have shown that a three-layered medical mask model with silver chloride composition in the middle layer, on both sides of the model, has antibacterial efficiency against three pathogens (E. Coli, K. Pneumoniae, and S. Aureus). The performance of this medical mask model has been found to meet the requirements for type I medical masks according to the EN 14863 standard. Studies have shown that the microbial purity of the mask model is CFU/g < 3.

No evidence for interstellar fireballs in the CNEOS database

Context. The detection of interstellar meteors, especially meteorite-dropping meteoroids, would be transformative, as this would enable direct sampling of material from other stellar systems on Earth. One candidate is the fireball observed by U.S. government sensors on January 8, 2014. It has been claimed that fragments of this meteoroid have been recovered from the ocean floor near Papua New Guinea and that they support an extrasolar origin. Based on its parameters reported in the Center for Near Earth Object Studies (CNEOS) catalog, the fireball exhibits a hyperbolic excess velocity that indicates an interstellar origin; however, the catalog does not report parameter uncertainties. Aims. To achieve a clear confirmation of the fireball’s interstellar origin, we assessed the underlying error distributions of the catalog data. Our aim was also to confirm whether the fragments of this meteoroid survived passage through the atmosphere and assess all conditions needed to unambiguously determine the fragments’ origin. Methods. We approached the investigation of the entire catalog using statistical analyses and modeling, and we provide a comprehensive analysis of the individual hyperbolic CNEOS cases. Results. We have developed several independent arguments indicating substantial uncertainties in the velocity and radiant position of the CNEOS events. We determined that all the hyperbolic fireballs exhibit significant deviations from the majority of the events in one of their velocity components, and we show that such mismeasurements can produce spurious parameters. According to our estimation of the speed measurement uncertainty for the catalog, we found that it is highly probable that such a catalog containing only Sun-bound meteors would show at least one event that appears highly unlikely to be Sun-bound. We also establish that it is unlikely that any fragments from a fireball traveling at the high inferred velocities could survive passage through the atmosphere. When assuming a much lower velocity, some fragments of this meteoroid could survive; however, they would be of a common Solar System origin and thus highly probable to be indistinguishable from the quantity of other local micrometeorites that have gradually accumulated on the sea floor. Conclusions. We conclude that there is no evidence in the CNEOS data to confirm or reject the interstellar origin of any of the nominally hyperbolic fireballs in the CNEOS catalog. Therefore, the claim of an interstellar origin for the fireball recorded over Papua New Guinea in 2014 remains unsubstantiated. We have also gathered arguments that refute the claim that the collected spherules from the sea floor originated in the body of this fireball.

Desorption efficiency and holding capacity of acid-treated filters for nicotine sampling in vape shops.

Efficient sampling materials are essential for assessing nicotine levels in vape shops and other settings where nicotine exposures may exist. Two different treatments of Whatman glass fiber type A (GF/A) filters (sodium bisulfate treated and citric acid treated) were evaluated for nicotine capture, desorption efficiency, and holding capacity using Gas Chromatography-Mass Spectrometry (GC-MS). The Filters were treated with 0.8mL of 0.1 M sodium bisulfate or citric acid solution and oven-dried (80 °C) for 30min. Nicotine was desorbed off the filters using a modified analytical method. The average nicotine desorption efficiency for sodium bisulfate-treated GF/A filters (98.4%) was significantly higher than that of citric acid-treated GF/A filters (60.9%) over a range of 1-100 µg nicotine. Sodium bisulfate-treated and citric acid-treated GF/A filters experienced a 10% nicotine breakthrough after being dosed with about 550 and 2,750 µg of nicotine, respectively compared to 75 µg for untreated GF/A filters. Citric acid-treated GF/A filters had a much greater nicotine-holding capacity, but nicotine desorption from citric acid-treated GF/A filters was below the recommended criteria. Therefore, we recommend that sodium bisulfate-treated GF/A filters are employed for sample of nicotine with the GC-MS method.

The role of transforming growth factor-β in lung damage in COVID-19: clinical and diagnostic parallels

BACKGROUND: Coronavirus 2 (SARS-CoV-2), which causes severe acute respiratory syndrome in COVID-19, leads to complex immune reactions, hyperactivation of immunocompetent cells, including increased degranulation activity of mast cells and the release of their secretome products. The SARS-CoV-2 virus and the subsequent strong immune and inflammatory response, as well as a violation of the regulation of coagulation and fibrinolytic pathways, cause massive activation of latent TGF-β in the lungs, as well as the latent pool of TGF-β in the blood of patients with COVID-19. AIMS: To assume the participation of transforming growth factor-β (TGF-β) in lung damage in patients with COVID-19 by determining its quantitative level in autopsy lung samples in patients with COVID-19 and to conduct a correlation analysis with clinical and laboratory parameters. MATERIALS AND METHODS: The study included samples of lung autopsy material obtained from patients who died from severe COVID-19. A correlation analysis of TGF-β-positive cells and clinical and laboratory parameters was also performed. RESULTS: Extensive representation of TGF-β-positive cells was found in lung tissues of patients who died from COVID-19.A negative correlation was revealed: between TGF-β and the content of nucleated neutrophils in the blood (r = - 0,617; p = 0,033); between TGF-β and the level of C-reactive protein (CRP) according to the results of blood biochemistry (r = - 0,491; p = 0,013). A positive correlation was revealed between TGF-β and the content of blood platelets (r = 0,384; p =0,012);TGF-β with the level of erythrocyte sedimentation rate (ESR) (r = 0,409; p = 0,025). A positive correlation was also found between TGF-β and the presence of cough in the patient at the beginning of hospitalization (r = 0,367; p = 0,046). CONCLUSIONS: Activation of TGF-β in the lungs of patients who died from severe COVID-19 correlates with the level of neutrophils, platelets, ESR, CRP and the presence of cough in the patient. Further research is needed on the activation, release of TGF-β and its interactions in larger cohorts of patients. These correlations suggest the negative involvement of the transforming growth factor and consider the therapeutic possibilities of regulatory influence on its activation.

Fungal microbiota of biodamages of various polymeric materials.

Data on microbial fouling of various synthetic polymer materials, including those used in space technology, are summarized. It has been established that the dominant groups of microbiota of polymer fouling are the genera of mitosporous fungi Aspergillus, Penicillium, Alternaria, Trichoderma. The enzymatic properties of fungal strains from the collection of microbial cultures of the Microbial Depository Center of the National Academy of Sciences of Armenia were studied. It has been shown that Aspergillus fumigatus, Penicillium chrysogenum, P. steckii, Juxtiphoma eupyrena and a number of other fungi have biofouling activity towards polyethylene, polyethylene terephthalate and some other synthetic polymers. New fungal kits have been developed and proposed to evaluate the fungal resistance of polymeric materials. They include fungi isolated from bio-damaged polymers used in space technology and contain 2 to 5 fungal strains instead of 7 to 9 strains in previously used kits. Taking into account the obtained data, a comparative assessment of the fungal resistance of samples of synthetic polymeric materials of various classes that passed accelerated climatic tests has been carried out. It has been established that the kits of biodegradant fungi, composed of cultures of bio-damaged space technology, generally exceeded the activity of the previously used kits, based on which one can judge the obvious advantages of strains isolated from bio-damaged space technology. In the future, these kits could find application not only for biodegradation of polymers, but also for testing the biostability of various polymers, to use for the construction of aviation and space techniques. Moreover, new optimized kits may be developed based on the strains involved in this study.

The Mechanical Properties of Orthodontic Aligners of Clear Aligner After Intraoral Use in Different Time Periods.

Although the technique of orthodontic aligners has risen in popularity, their mechanical properties have not been thoroughly investigated. The aim of this study was to evaluate the mechanical properties of the orthodontic aligners Clear Aligner after intraoral use for 7, 10 and 14 days, and to compare them with as-received aligners (0 days). It was also sought to examine the properties of the unprocessed raw material (polyethylene glycol terephthalate) used to manufacture these aligners. Thirty-two aligners by four patients were evaluated and studied at 0, 7, 10, 14 days of use. Each aligner was divided into three segments (two posterior and one anterior), which resulted in 96 samples. Also, 16 samples of unprocessed material were studied. For all samples, elastic modulus, ultimate tensile stress (UTS) and yield stress were calculated by conducting tensile testing. Additionally, material hardness was tested. The two-tailed Mann-Whitney test was performed, having set the level of significance at p = 0.05. Analysis of the measurements indicated a statistically significant decrease in elastic modulus between days 0 and 14 of use, of UTS between days 0 and 7, 7 and 10, and of yield stress between days 0 and 7. For hardness, in every period, posterior segments demonstrated significantly higher values than anterior segments. All properties of the unprocessed material were statistically significantly higher than the processed samples. The unprocessed material presented significant differences in every property tested in comparison to the processed aligners. The processed material showed further deterioration over time during use. The present study provides evidence that thermoforming and ageing affect the mechanical properties of the aligners.

Geomechanical aspects of stabilizing arsenic trioxide roaster waste in cemented paste backfill at the Giant Mine, Canada

Giant Mine, an abandoned gold mine near Yellowknife in the Northwest Territories of Canada, generated significant arsenic trioxide roaster waste (ATRW) during its operations, posing a substantial environmental hazard. This study explored the feasibility of stabilizing ATRW by incorporating it into cemented paste backfill (CPB). Using response surface methodology (RSM), CPB samples with varying mixing ratios were analyzed to identify key parameters influencing strength. Unconfined compressive strength (UCS) tests assessed physical stability, while saturated hydraulic conductivity and computed tomography (CT) analyses examined the microstructure of the CPB. The results revealed that CPB samples prepared with general use (GU) cement exhibited significantly higher strength than those with a GU and lime kiln dust (LKD) mixture. Binder and solid contents were identified as the most critical factors influencing UCS, with binder content having a more pronounced influence. Curing time was found to be non-significant. Higher binder and solid contents correlated with higher UCS values in the CPB samples. The addition of 10% wt. ATRW reduced the UCS by over 30%, particularly in samples with lower binder and solid contents. Although microstructure differences were not evident in saturated hydraulic conductivity tests, CT scans showed increased formation of high-density arsenic-containing materials in samples with the highest UCS, especially those using GU binder. These findings suggest that optimizing binder and solid contents is crucial for enhancing CPB strength and effectively stabilizing ATRW.

Deformation localisation in stretched liquid crystal elastomers

We model within the framework of finite elasticity two inherent instabilities observed in liquid crystal elastomers under uniaxial tension. First is necking, which occurs when a material sample suddenly elongates more in a small region where it appears narrower than the rest of the sample. Second is shear striping, which forms when the in-plane director rotates gradually to realign and become parallel with the applied force. These phenomena are due to the liquid crystal molecules rotating freely under mechanical loads. To capture necking, we assume that the uniaxial order parameter increases with tensile stretch, as reported experimentally during polydomain-monodomain transition. To account for shear striping, we maintain the uniaxial order parameter fixed, as suggested by experiments. Our finite element simulations capture well these phenomena. As necking in liquid crystal elastomers has not been satisfactorily modelled before, our theoretical and numerical findings related to this effect can be of wide interest. Shear striping has been well studied, yet our computed examples also show how optimal stripe width increases with the nematic penetration depth measuring the competition between the Frank elasticity of liquid crystals and polymer elasticity. Although known theoretically, this result has not been confirmed numerically by previous nonlinear elastic models.

Developing a DNA Methylation Signature to Differentiate High-Grade Serous Ovarian Carcinomas from Benign Ovarian Tumors.

Epithelial ovarian cancer (EOC) represents a significant health challenge, with high-grade serous ovarian cancer (HGSOC) being the most common subtype. Early detection is hindered by nonspecific symptoms, leading to late-stage diagnoses and poor survival rates. Biomarkers are crucial for early diagnosis and personalized treatment OBJECTIVE: Our goal was to develop a robust statistical procedure to identify a set of differentially methylated probes (DMPs) that would allow differentiation between HGSOC and benign ovarian tumors. Using the Infinium EPIC Methylation array, we analyzed the methylation profiles of 48 ovarian samples diagnosed with HGSOC, borderline ovarian tumors, or benign ovarian disease. Through a multi-step statistical procedure combining univariate and multivariate logistic regression models, we aimed to identify CpG sites of interest. We discovered 21 DMPs and developed a predictive model validated in two independent cohorts. Our model, using a distance-to-centroid approach, accurately distinguished between benign and malignant disease. This model can potentially be used in other types of sample material. Moreover, the strategy of the model development and validation can also be used in other disease contexts for diagnostic purposes.

Optimizing ZnSe nanorods with La doping for structural, electrical, and dielectric properties in device applications

Nano-materials, pure Zinc Selenide (ZnSe), and rare earth (Lanthanum) doped ZnSe (Zn1-xLaxSe, x = 0.00, 0.02, 0.04, 0.06) were synthesized via a facile and low-cost hydrothermal method. X-ray diffraction (XRD) demonstrated that the nanoparticles grow in cubic crystal phase with high degree crystallinity, and the measured crystallite size of La-doped ZnSe ranges from 31.95 to 31.11 nm. Mitigation in crystallite size was observed with the inclusion of La and enhancement in the lattice constant ‘a’ from 5.6565 Å to 5.6818 Å. Morphological study (FESEM) depicts synthesized materials' morphologies as nanorods. The FESEM images indicate the random distribution of the nanorods across the crystal lattice, regardless of the accumulation of the nanorods, showing lumps in the synthesized material sample. The estimated grain size of pure ZnSe nanorods ranges from 137.6 to 496.9 nm. Electrical features revealed that direct current (DC) electrical conductivity ‘σdc’ enhances with temperature, affirming the semiconducting behavior of the materials. Increased lanthanum content enhances the ‘σdc’ from 3.08 × 10–5 (Ω cm)-1 to 5.94 × 10–5 (Ω cm)-1 at 303 K while lessening the activation energy value from 0.134 to 0.104 eV. Dielectric features, including relative permittivity (ε'), loss factor or dielectric loss (ε''), tangent loss (tanδ), as well as AC conductivity (σac), indicate a direct proportionality with temperature, and elevated values of all the dielectric parameters are noted with La-doping. An increase in dielectric constant with doping concentration displayed that the prepared nanocrystals have valuable dielectric and capacitive behavior. The outcomes of electrical and dielectric features display that the prepared nanorods have vital characteristics for developing optoelectronic devices, solar cells, photocatalysts, and light-emitting diode applications.

Organophosphate esters (OPEs) in the air and dust of new vehicle cabins: Concentrations, sources and contributions

Vehicles cabin represents unique indoor environment characterized by its limited space and multiple interior materials. For the first time, OPEs levels in vehicles and OPEs content in cabin materials were measured, and the material contributions were also analyzed. Between May and July in 2023, air, dust and materials samples were collected from 32 new vehicles. The detection rates were as high as 71%–100 % in dust and 100 % in selected cabin materials. The median of ∑OPEs in air-phase (both gas and particles) was significantly higher at 589.26 ng/m3 compared to those in other vehicle investigations. Material content analysis revealed that the top three were cushion textile, mat and lubricant, with ∑OPEs ranging from 85.94 μg/g to 1406.04 μg/g, which were three orders of magnitude higher than those in toys. Chlorinated forms such as TCIPP and TDCIPP were predominant among all air, dust and material samples analyzed. Particle-phase OPEs provided statistic diversity on manufactures and seat materials. Positive Matrix Factorization (PMF) analysis found that the combination of cushion textile, seat leather, and carpet substrate textile contributed significantly, accounting for 68 % of cabin OPEs.

Integration of Transcriptome and Metabolome Reveals Wax Serves a Key Role in Preventing Leaf Water Loss in Goji (Lycium barbarum)

Drought stress is one of the main abiotic stresses that limit plant growth and affect fruit quality and yield. Plants primarily lose water through leaf transpiration, and wax effectively reduces the rate of water loss from the leaves. However, the relationship between water loss and the wax formation mechanism in goji (Lycium barbarum) leaves remains unclear. ‘Ningqi I’ goji and ‘Huangguo’ goji are two common varieties. In this study, ‘Ningqi I’ goji and ‘Huangguo’ goji were used as samples of leaf material to detect the differences in the water loss rate, chlorophyll leaching rate, wax phenotype, wax content, and components of the two materials. The differences in wax-synthesis-related pathways were analyzed using the transcriptome and metabolome methods, and the correlation among the wax components, wax synthesis genes, and transcription factors was analyzed. The results show that the leaf permeability of ‘Ningqi I’ goji was significantly lower than that of ‘Huangguo’ goji. The total wax content of the ‘Ningqi I’ goji leaves was 2.32 times that of the ‘Huangguo’ goji leaves, and the epidermal wax membrane was dense. The main components of the wax of ‘Ningqi I’ goji were alkanes, alcohols, esters, and fatty acids, the amounts of which were 191.65%, 153.01%, 6.09%, and 9.56% higher than those of ‘Huangguo’ goji, respectively. In the transcriptome analysis, twenty-two differentially expressed genes (DEGs) and six transcription factors (TFs) were screened for wax synthesis; during the metabolomics analysis, 11 differential metabolites were screened, which were dominated by lipids, some of which, like D-Glucaro-1, 4-Lactone, phosphatidic acid (PA), and phosphatidylcholine (PE), serve as prerequisites for wax synthesis, and were significantly positively correlated with wax components such as alkanes by the correlation analysis. A combined omics analysis showed that DEGs such as LbaWSD1, LbaKCS1, and LbaFAR2, and transcription factors such as LbaMYB306, LbaMYB60, and LbaMYBS3 were strongly correlated with wax components such as alkanes and alcohols. The high expression of DEGs and transcription factors is an important reason for the high wax content in the leaf epidermis of ‘Ningqi I’ goji plants. Therefore, by regulating the expression of wax-synthesis-related genes, the accumulation of leaf epidermal wax can be promoted, and the epidermal permeability of goji leaves can be weakened, thereby reducing the water loss rate of goji leaves. The research results can lay a foundation for cultivating drought-tolerant goji varieties.

Comparing the Efficacy of the Medicinal Products Expresstabs® and Inspector Quadro in Treating Otodectosis in Foxes in Fur Farming Conditions

Introduction. Fur farming is a cost-effective sector of Russian agriculture, therefore the livestock health issues are relevant. The growth, development and productivity of fur caged breeding animals are affected by various biotic and abiotic factors. Among the biotic factors are diseases, in particular invasive ones, caused, among other things, by ectoparasites. Pathogens associated with ectoparasites often infect fur animals and are widespread. The aim of our work is to study the efficacy of using the medicinal products ExpressTabs® and Inspector Quadro Tabs in treating the otodectosis in foxes in fur farming conditions.Materials and Methods. The study was carried out with 30 caged breeding foxes aged 2 years at Fur Farm “Savvatevo” LLC (Tver Region, Savvatevo village). Foxes were divided into 2 experimental and 1 control groups. Foxes were preliminarily examined clinically, samples of material from the auricles and external auditory canals were taken to find the ear mites Otodectes cynotis. The ExpressTabs® was used in foxes for the first time. The ExpressTabs® and Inspector Quadro Tabs were used according to the instructions, individually, perorally, with a small amount of feed and subsequent observation. To assess the efficacy of the medicinal products, control sampling and microscopy of material from the auricles and external auditory canals were carried out 48 hours, 7 days and 28 days after the start of the experiment. Blood samples were also taken to monitor the parameters before and after administration of the ExpressTabs®.Results. Based on the results of the experiment, we have established the high efficacy of the antiparasitic drugs ExpressTabs® and Inspector Quadro Tabs in treating fox otodectosis in caged breeding conditions. When using the ExpressTabs®, the efficacy was 90% against the ear mite O. cynotis: on the 28th day after the start of using the medicinal product, during the examination of foxes using microscopy, we found only one animal having 4 specimens of O. cynotis in the material from the auricles and external auditory canals, however, all the mites were motionless and without signs of life. The efficacy of the Inspector Quadro Tabs against the ear mite O. cynotis was 80%: on the 28th day, during the examination, only two animals were found to have mites in the scrapings, however, also without signs of life. According to the blood test results, the drug ExpressTabs® proved to have no any pronounced toxic effect on the body of foxes and is safe for use in caged keeping conditions.Discussion and Conclusion. The drugs ExpressTabs® and Inspector Quadro Tabs have shown high efficacy in foxes with otodectosis. These medicinal products can be introduced into the veterinary practices of the fur farms for treating foxes with otodectosis.

Effects of Humidity on Mycelium-Based Leather.

Leather is a product that has been used for millennia. While it is a natural material, its production raises serious environmental and ethical concerns. To mitigate those, the engineering of sustainable biobased leather substitutes has become a trend over the past few years. Among the biobased materials, mycelium, the fungal "root" of a mushroom, is one of the promising alternatives to animal leather, as a material with tunable physicomechanical properties. Understanding the effect of humidity on mycelium-based leather material properties is essential to the production of durable, competitive, and sustainable leather products. To this end, we measured the water sorption isotherms on several samples of mycelium-based leather materials and investigated the effects of water sorption on their elastic properties. The ultrasonic pulse transmission method was used to measure the wave speed through the materials while measuring their sorption isotherms at different humidity levels. Additionally, the material's properties were mechanically tested by performing uniaxial tensile tests under ambient and immersed conditions. An overall reduction in elastic moduli was observed during both absorption and immersion. The changes in the measured longitudinal modulus during water sorption reveal changes in the elasticity of the test materials. The observed irreversible variation of the longitudinal modulus during the initial water sorption can be related to the material production process and the presence of various additives that affect the mechanical properties of the leather materials. Our results presented here should be of interest to material science experts developing a new generation of sustainable leather products.

Pre‐oxidized Recycled MgO–Steel Composite Material for Possible Application in Cryolitic Melts

Recycled MgO–C lining bricks and 316L stainless steel are used to manufacture composite material for inert anode samples for aluminum electrolysis cell. The microstructure of the composite material is characterized after preoxidation thermal treatments at 800, 900, and 1000 °C as well as in its sintered state. Preoxidation (PO) process is designed to enhance the material's corrosion resistance in molten cryolite environments by developing robust Fe–Mg–O, Fe–Cr–O‐ containing phases. Analytical techniques including scanning electron microscopy, electron backscatter diffraction, and energy dispersive X‐ray spectrometry are applied to characterize the phase formation, revealing the potential of these composites for use as inert anodes in aluminum electrolysis cells. PO at 800 °C is not sufficient to form adequate protective oxide layers. Whereas, PO at 900 and 1000 °C leads to the formation of protective oxide layers containing Mg–O Fe–O halite‐like solid solutions and (Cr,Fe)3O4 spinel phase. Sample, preoxidized at 1000 °C is sealed in Mg–Fe–O spinel phase.

МОДЕЛЮВАННЯ ТА ОПТИМІЗАЦІЯ РЕЖИМУ ТЕРМООБРОБКИ ТРУБЧАСТИХ ЕЛЕМЕНТІВ ФЕРМЕННИХ КОНСТРУКЦІЙ ЛІТАЛЬНИХ АПАРАТІВ З ВУГЛЕПЛАСТИКУ

The article analyzes the current state of development of dimensionally stable tubular elements (TE) and technological problems arising during their production. It is shown that along with empirical methods of studying the influence of various technological schemes on the dimensional stability of tubular elements, it is useful to use the optimal temperature-time mode for heat treatment and, based on it, select the optimal technological scheme. Modeling and determination of the optimal mode of heat treatment of tubular elements were performed. The study of the TE heat treatment mode was carried out in two stages, first by methods of mathematical modeling and optimization, and then by empirical enumeration of various technological schemes. At the first stage, the material properties, which are parameters of the mathematical model, were studied, and the optimal curing modes were calculated. At the second stage, the calculated optimal curing modes were supplemented with various technological methods that cannot be mathematically modeled, and a study was carried out on the influence of the resulting combined heat treatment mode on the geometric characteristics and dimensional stability of carbon fiber TE. The mathematical model of the process of heat treatment and curing of TE in a heat chamber, when heated by a heating air flow, is a system of differential equations: thermal conductivity and curing kinetics. A mathematical model of the process of heat treatment of tubular elements manufactured by the winding method is proposed, the ways of optimizing the curing mode of carbon fiber TE are shown. A numerical calculation of temperature-conversion fields during curing and calculation of optimal curing modes of tubular elements are performed taking into account various process schemes. The values of heat capacity C and thermal conductivity l are calculated depending on the temperature T, the degree of curing b and the filling coefficient g, Безфітингова ферма з вуглепластику Безфітингова ферма з вуглепластику Безфітингова ферма з вуглепластику the power of heat release W and the thermal effect of the curing reaction Q of carbon fiber. Optimum curing modes for a plate made of composite polymer material are obtained, calculated from the data obtained as a result of studying material samples. Temperature-time curing modes are obtained, which are optimized for different thicknesses of the studied material. The statistical hypothesis about the significance of the influence of the process flow chart and reinforcement pattern on the wall thickness of a tubular element and its compressive strength was proved by the dispersion analysis method. The influence of process flow charts and heat treatment modes on the geometric and mechanical characteristics of carbon fiber tubular elements of aircraft truss structures was studied. The statistical hypothesis about the significance of the influence of the process flow chart and reinforcement pattern on the deviation of the wall thickness of tubular elements and their strength characteristics was tested. The significance of the influence of process flow charts with different heat treatment modes on the average wall thickness of a carbon fiber tubular element was statistically proven.

Development of an intelligent geographic information system for mountain roads monitoring: Ground data collection and analysis

This study examines the development of an intelligent geographic information system for mountain road monitoring. To make well-informed and timely management decisions in the planning, construction, and maintenance of mountain roads, and to anticipate potential critical situations and their effects on road conditions, it is imperative to employ modern methodologies. This study involves data collection from a specific section of a mountain road situated near Almaty, Kazakhstan. We gathered data on the road section through visual assessment, measurements of the coefficient of adhesion, and the acquisition of material samples from the structural layers of the roadbed. Based on the visual assessment and surface adhesion measurements, it became evident that the deformation of the studied road section, which includes a network of cracks and "non-standard" transverse cracks, is attributed to mountain mass shifts and water flows from slopes. Laboratory analysis of the collected samples revealed that excessive water saturation could result in cracks during freeze-thaw cycles, while a low resistance coefficient would lead to softening during humid conditions. An Intelligent Geographic Information System (IGIS) will incorporate the collected data alongside open remote sensing and weather data. The objective is to utilize this integrated system in the future for forecasting road conditions and maintenance requirements for similar roads in mountainous regions of the area. The measurements are carried out according to the state standards. That makes the system useful for government management purposes.

Acoustic materials based on the Gosper curve

In this work, slotted acoustic materials based on a space filling curve called the Peano-Gosper curve are proposed and investigated. The slits in such materials form a complex pattern because they are divided by walls built along lines generated by the Gosper curve algorithm. The pattern can be twisted around an axis normal to its surface to increase the tortuosity inside the material, and therefore, modify its acoustic properties, which can be controlled by the turning angle or pitch of the twist. A highly efficient semi-analytical model has been developed to accurately predict the acoustic properties, in particular the sound absorption of such materials. It only requires a representative part of the pattern, or better, scanning the surface of the fabricated material so that the actual geometry and dimensions (in particular slit widths) are well reproduced in a two-dimensional finite element mesh generated on a representative fluid domain. The mesh is used to solve a dedicated Poisson problem and determine a few key parameters, and the rest of the modelling is based on analytical formulas. Material samples with straight and twisted slit patterns were 3D printed and then measured in an impedance tube to confirm semi-analytical sound absorption predictions.