Search Results (1,063)

This article presents the synthesis, electrophysical, and catalytic properties of a La_0.9MnO₃–LaFeO₃ nanocomposite material. The nanocomposite was synthesized via the sol–gel (Pechini) method. X-ray diffraction (XRD) analysis revealed a polycrystalline, biphasic perovskite structure combining both hexagonal and cubic symmetry. The microstructure and elemental composition, examined using field emission scanning electron microscopy (FESEM), indicated an average particle size of approximately 186.9 nm. The composite exhibits semiconducting behavior within the temperature ranges of 293–323 K and 343–393 K. Developing electrocatalysts free of precious metals for the hydrogen evolution reaction (HER) is increasingly important to facilitate the production of hydrogen from renewable sources. In this study, the conductive La_0.9MnO₃–LaFeO₃ composite was deposited on graphite and, for the first time, evaluated as an electrocatalyst for HER in acidic media. The resulting composite films were tested using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) in a glassy carbon electrode (GCE) setup, providing insights into their potential as effective, cost-efficient electrocatalysts. Full article

This article presents a study on the precipitation of copper from the cyanide leaching solutions used for gold–copper ores, both with and without the addition of a sulphidizer (Na₂S). Mathematical models were developed to summarize the effects of the pH, initial copper concentration, and Na₂S stoichiometric ratio on the precipitation process, using an experimental design based on a probabilistic–deterministic method. Varying the stoichiometric ratio of Na₂S has a minimal impact on the precipitation process. However, the presence of a sulphidizer is significant, as the precipitation process occurs at pH levels of 5 and below. The initial concentration of copper in the solution was identified as the most significant factor. At copper concentrations of 0.34% and 1.55% (pH = 3), the precipitation rates were 51.48% and 47.6%, respectively. This study also determined that the most effective method across the entire range of copper concentrations in the solution was the precipitation of copper in the form of copper cyanide hydrate (CuCN∙nH₂O) without the addition of Na₂S. At copper concentrations of 0.34% and 1.55% (pH = 3), the precipitation rates were 86.47% and 85%, respectively. The pH level was the most significant factor influencing this process, as copper deposition without Na₂S did not occur at a pH of 5. The obtained models allow us to accurately predict the influence of factors on the deposition process. Aided by the mathematical model of precipitation (without Na₂S), we selected the conditions for an enlarged experiment using 20 L of solution (Cu = 0.34%, pH = 3.2), which showed the high efficiency of the method. The calculated recovery amounted to 86%, where practical recovery was 87.2%, and divergence was ≥1.2%. Full article

Obesity leads to a chronic inflammatory state throughout the body, with increased infiltration of immune cells and inflammatory factors in skeletal muscle tissue, and, at the same time, the level of intracellular mitochondrial oxidative stress rises. Meanwhile, obesity is closely related to the development of skeletal muscle fibrosis and can affect the metabolic function of skeletal muscle, triggering metabolic disorders such as insulin resistance (IR) and type 2 diabetes (T2D). However, whether there is a mutual regulatory effect between the two pathological states of inflammation and fibrosis in obese skeletal muscle and the specific molecular mechanisms have not been fully clarified. This review focuses on the pathological changes of skeletal muscle inflammation and fibrosis induced by obesity, covering the metabolic changes it causes, such as lipid deposition, mitochondrial dysfunction, and dysregulation of inflammatory factors, aiming to reveal the intricate connections between the two. In terms of intervention strategies, aerobic exercise, dietary modification, and pharmacotherapy can improve skeletal muscle inflammation and fibrosis. This article provides insight into the important roles of inflammation and fibrosis in the treatment of obesity and the management of skeletal muscle diseases, aiming to provide new ideas for the diagnosis and treatment of metabolic diseases such as obesity and IR. Full article

The interaction of pulsed lasers with matter involving nanomaterials as a pure target or thin layer deposited on a target initiates transient plasma, which shows strong enhancement in a spectral line emission. This domain of research has been explored via two well-established techniques dubbed NELIBS and NELIPS. These Nano-Enhanced Laser-Induced Breakdown or Plasma Spectroscopy techniques entail similarities as well as differences. The newly defined concept of Nano-Enhanced Laser-Induced Plasma Spectroscopy NELIPS is introduced. Thereupon, certain confusion has arisen from various aspects of the similarities as well as differences between the two techniques. In this article, we will investigate the application of either technique to retrieve relevant data about the enhanced spectral line plasma emission phenomenon. To discriminate between these two techniques, a survey on the nature of the target, the origin of enhancement and prevalent theoretical approaches is presented. In this context, the potential achievements, challenges and expected prospects are comparatively highlighted. This review emphasizes the unique contributions of NELIPS, particularly the advanced approach in nanoscale thermal modeling and spectroscopic applications. Full article

The current understanding of organic matter enrichment in marine shales remains highly controversial. Most scholars argue that deeper water environments and warmer climates facilitate the enrichment of organic matter. However, this perspective contradicts the principles of carbon sequestration in environmental science, necessitating a more in-depth discussion of its underlying mechanisms. This article utilizes the Wufeng–Longmaxi shales in the Sichuan Basin as a case study and integrates the primary productivity and carbon sequestration patterns observed in modern water bodies to analyze the processes governing organic matter enrichment in shales. The findings indicate that the Wufeng–Longmaxi shales in the Sichuan Basin did not form in a deep-water shelf environment during a period of large-scale transgression; rather, they developed in a highly enclosed shallow-water environment during a regressive phase. The proximity to ancient land correlates with higher organic matter abundance and gas production, suggesting that the mineralization model closely resembles that of coal, thereby highlighting the significance of proximity to land and the supply of terrigenous materials. It can be concluded that the depositional environment of organic-matter-rich marine shales is characterized by four key attributes: a shallow water depth, proximity to land (with a supply of terrestrial materials), a high enclosure, and a cold climate. Full article

The ASPECT-BET project, or An sdd-SPECTrometer for BETa decay studies, aims to develop a novel technique for the precise measurement of forbidden beta spectra in the 10 keV–1 MeV range. This technique employs a Silicon Drift Detector (SDD) as the main spectrometer with the option of a veto system to reject events exhibiting only partial energy deposition in the SDD. A precise understanding of the spectrometer’s response to electrons is crucial for accurately reconstructing the theoretical shape of the beta spectrum. To compute this response, GEANT4 simulations optimized for low-energy electron interactions are used and validated with a custom-made electron gun. In this article we present the performance of these simulations in reconstructing the electron spectra measured with SDDs of a ¹⁰⁹Cd monochromatic source, both in vacuum and in air. The allowed beta spectrum of a ¹⁴C source was also measured and analyzed, proving that this system is suitable for the application in ASPECT-BET. Full article

The mixing of hydrothermal vent fluids with deep ocean water and near-vent pelagic matter results in particle populations with a complex composition consisting of hydrothermally derived, rock-forming, and biogenic particles. This study is the first investigation of deep sediment trap material collected at the Jan Mayen hydrothermal vent field area at 71° N and 6° W of the southernmost Mohns Ridge in the Norwegian–Greenland Sea. This area is characterized by high magmatic activity, axial volcanic ridges, and mafic-hosted volcanogenic massive sulfide deposits. Data on sinking particle fluxes from two hydrothermal settings, the Troll Wall and Soria Moria vent fields, located about 4 km apart, are discussed in the article. In particular, the study emphasize the differences between two hydrothermal settings from each other that demonstrate the geodiversity of hydrothermal processes within the relatively shallow Jan Mayen hydrothermal vent field area affected by the Iceland and Jan Mayen hotspots. The fluxes of sinking hydrothermally derived particles (barite, gypsum, non-crystalline Fe-Si oxyhydroxides, and Fe, Zn, and Cu sulfides) obtained at the Jan Mayen hydrothermal vents made it possible to elucidate the characteristic features of their buoyancy plumes and compare them with similar data reported for other submarine hydrothermal systems. In terms of the composition of the deep-sea hydrothermal particles from buoyant plumes, the studied vent fields are most similar to the Menez Gwen and Lucky Strike vent fields affected by the Azores hotspot. The supply of hydrothermally derived matter is accompanied by normal pelagic/hemipelagic sedimentation, which is dominated by biogenic particles, especially in the upper water layers. Full article

The objective of this systematic review (SR) was to select studies on the activity of glycerol as a molecule that induces disease resistance in plants. We sought to evaluate articles deposited in five electronic databases using a search string and predefined inclusion and exclusion criteria. The most studied crops are Arabidopsis thaliana, Glycine max, and Coffea spp. The most commonly cited biotic agents include Pseudomonas syringae, Blumeria graminis, and Colletotrichum higginsianum. Numerous doses of glycerol were studied, and concentrations ranged from 0.004 to 9.21%, with a 3% concentration of glycerol being considered most effective for most plant species, where greater resistance was observed with increased glycerol-3-phosphate (G3P) and decreased oleic acid levels. The main means of application of the product were spraying and immersion. The SR also revealed the evaluation of resistance-inducing genes, such as PR proteins (PR-1, PR2, PR-5, etc.), HPS70, HSP90, SCAM4, and Tapr1, among others. The information collected in this SR helps to understand the state of the art on the use of glycerol as a molecule inducing resistance against biotic stressors to understand the mechanisms involved in most host–pathogen relationships. This information will be useful in plant breeding programs and for growers/producers. Full article

In this article, we report on the research on the synthesis of composites based on a porous, highly ordered silica material modified by a metallic nanophase and chitosan biofilm. Due to the ordered pore system of the SBA-15 silica, this material proved to be a good carrier for both the biologically active nanophase (highly dispersed silver nanoparticles, AgNPs) and the adsorption active phase (chitosan). The antimicrobial susceptibility was determined against Gram-positive Staphylococcus aureus ATCC 25923, Gram-negative bacterial strains (Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 700603, and Pseudomonas aeruginosa ATCC 27853), and yeast Candida albicans ATCC 90028. The zones of microbial growth inhibition correlated with the content of silver nanoparticles deposited in the composites and were the largest for C. albicans (14–21 mm) and S. aureus (12–17 mm). The suitability of the composites for the purification of water and wastewater from anionic pollutants was evaluated based on kinetic and equilibrium adsorption studies for the dye Acid Red 88. The composite with the highest amount of the chitosan component showed the greatest adsorption capacity (a_m) of 0.57 mmol/g and the most effective kinetics with a rate constant (log k) and half-time (t_0.5) of −0.21 and 1.62 min, respectively. Due to their great practical importance, AgNP–chitosan–silica composites can aspire to be classified as functional materials combining the environmental problem with microbiological activity. Full article

This article compares the properties of the diamond-like carbon (DLC) coating with those of ZrN and (Zr,Hf)N coatings deposited on the Ti-6Al-4V titanium alloy substrate. To improve substrate adhesion during the deposition of the DLC coating, preliminary etching with chromium ions was conducted, ensuring the formation of a chromium-saturated diffusion surface layer in the substrate. A Si-DLC layer followed by a pure DLC layer was then deposited. The hardness of the coatings, their surface morphology, fracture strength in the scratch test, and tribological properties and wear resistance in the pin-on-disk test in contact with Al₂O₃ and steel indenters were investigated. The structure of the DLC coating was studied using transmission electron microscopy, and its corrosion resistance in an environment simulating blood plasma was also investigated. In the pin-on-disk test in contact with Al₂O₃ and AISI 52100 indenters, the DLC-coated sample demonstrates a much lower friction coefficient and significantly better wear resistance compared to the nitride-coated and uncoated samples. Both nitride coatings—(Zr,Hf)N and ZrN—and the DLC coating slow down the corrosive dissolution of the base compared to the uncoated sample. The corrosion currents of the (Zr,Hf)N-coated samples are 37.01 nA/cm², 20% higher than those of the ZrN-coated samples. The application of (Zr,Hf)N, ZrN, and DLC coatings on the Ti-6Al-4V alloy significantly inhibits dissolution currents (by 30–40%) and increases polarization resistance 1.5–2.0-fold compared to the uncoated alloy in 0.9% NaCl at 40 °C. Thus, the DLC coating of the described structure simultaneously provides effective wear and corrosion resistance in an environment simulating blood plasma. This coating can be considered in the manufacture of medical products (in particular, implants) from titanium alloys, including those functioning in the human body and subject to mechanical wear (e.g., knee joint endoprostheses). Full article

Nowadays, polycrystalline lead telluride is one of the premier substances for thermoelectric devices while remaining a hopeful competitor to current semiconductor materials used in mid-infrared photonic applications. Notwithstanding that, the development of reliable and reproducible routes for the synthesis of PbTe thin films has not yet been accomplished. As an effort toward this aim, the present article reports progress in the growth of polycrystalline indium-doped PbTe films and their study. The introduction foregoing the main text presents an overview of studies in these and closely related research fields for seven decades. The main text reports on the electron-beam-assisted physical vapor deposition of n-type indium-doped PbTe films on two different amorphous substrates. This doping of PbTe is unique since it sets electron density uniform over grains due to pinning the Fermi level. In-house optimized parameters of the deposition process are presented. The films are structurally characterized by a set of techniques. The transport properties of the films are measured with the original setups described in detail. The infrared transmission spectra are measured and simulated with the original optical-multilayer modeling tool described in the appendix. Conclusions of films’ quality in terms of these properties altogether are drawn. Full article

This article is devoted to the study of the Quaternary aeolian sands of the boreal zone of north Asia. Using the example of the study reference sections of the Selenga Dauria (Western Transbaikalia), it was established that the activation of aeolian processes is determined by the complex interaction of natural and anthropogenic factors. Natural factors include neotectonic movements; wide distribution of alluvial and lacustrine-alluvial deposits; a sharply continental semi-arid climate; and forest-steppe and steppe vegetation. Among the anthropogenic factors, the leading ones are deforestation, plowing of land and construction of new settlements, roads and other line structures. The obtained radiocarbon dating of buried soils and coal from ancient fire pits indicates the activation of aeolian processes during the Holocene. The main sources for aeolian transport (winnowing) are sands located in the areas of river and lake beaches, floodplains and river terraces. Almost all aeolian sands of the boreal zone were formed as a result of short-range wind transport. They form mini-deserts unfixed by vegetation, with active aeolian processes, dunes, barkhans and deflationary basins. Aeolian swells and blowout basins characterize aeolian landscapes weakly fixed by vegetation. It is noted that aeolian deposits of the boreal zone of north Asia, in contrast to similar sands of the subtropical and tropic zones, consist of coarser-grained material. Medium- and fine-grained sands dominate their composition, which is polymineral and well-sorted. In subtropical and tropical deserts, they are predominantly monomineral, fine and fine-grained. At the same time, mainly minerals that are unstable to weathering (feldspars, plagioclases, pyroxenes and amphiboles) represent the mineralogical composition of the studied aeolian sands. Weathering-resistant minerals dominate the sands of classical deserts: quartz, leucoxene, ilmenite, epidote, zircon, garnets, tourmaline, rutile and others. Modern aeolian landscapes are a unique natural formation for the boreal zone of north Asia and can be successfully used for the development of ecotourism. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a refined categorization of non-alcoholic fatty liver disease (NAFLD), highlighting the intricate relationship between hepatic steatosis and metabolic dysfunction. Abdominal obesity (AO), a key diagnostic criterion for metabolic dysfunction, predominantly results from inappropriate diet and unhealthy dietary habits. To comprehensively investigate which dietary factors contribute to MASLD through AO and to understand the underlying biological mechanisms, we initially conducted a systematic review of meta-analysis articles in the PubMed database from the past decade, summarizing dietary factors that affect AO. Subsequently, we conducted targeted searches in the PubMed database for these dietary factors and provided a narrative review of the mechanisms of how these dietary factors lead to AO and how AO exacerbates MASLD. A diet characterized by excessive intake of energy, carbohydrates, fructose, or ultra-processed foods (UPFs) is considered inappropriate. Inappropriate diet leads to the formation of MASLD and AO by enhancing pathways such as de novo lipid synthesis (DNL) in the liver, insulin resistance (IR), gut–liver dysfunction, and inflammation. Dietary interventions for inappropriate diets can effectively intervene in and improve MASLD and AO. The mechanism of inappropriate diet on abdominal fat deposition is through excessive energy or the activation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) to increase endocortisol secretion. Then, the excessive accumulation of visceral fat facilitates a rapid and augmented flux of free fatty acids (FFAs) to the liver and initiates a series of deleterious effects, including oxidative stress (OS), endoplasmic reticulum stress (ERS), activation of protein kinase C (PKC) pathways, and inflammation. Additionally, FFAs may mediate excessive lipid deposition and hepatocellular damage through the action of hormones. These pathways to liver damage exacerbate MASLD and progression to metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis. Furthermore, investigating other potential mechanisms by which AO may influence MASLD could offer new recommendations for the treatment guidelines of MASLD. Full article

Tunnel oxide passivating contact cells have become the mainstream form of high-performance photovoltaic cells; however, the key factor restricting the further improvement of tunnel oxide passivating contact cell performance lies in the deposition process technology of high-quality polysilicon films. The experimental optimization cost for the deposition of large-sized polysilicon films in low-pressure chemical vapor deposition reactors is enormous when conducted in the temperature range of 800–950 K; hence, the necessity to develop effective computer simulation models becomes urgent. In recent years, our research group has conducted two-dimensional simulation research on large-sized, low-pressure chemical vapor deposition. This article focuses on analyzing the influence of gas-phase chemical reactions on the contribution rate of polysilicon film deposition under a mixed atmosphere of H₂ and SiH₄. The findings indicate that when using SiH₄ as the precursor reactants with a gas pressure not exceeding 100 Pa, SiH₄ contributes more than 99.6% to the deposition of polysilicon films, while the contribution rate of intermediates from chemical reactions to film deposition is less than 0.5% with 860–900 K. The influence of temperature on the contribution rate of gas-phase intermediates is negligible. It is found that simulating complex multi-step chemical reactions is highly resource-intensive, making it difficult to achieve the three-dimensional simulations of large-sized tubular LPCVD reactors. Based on the in-depth analysis of the mechanism and simulation results, a simplified model neglecting the complex multi-step chemical reaction process has been proposed. Through employing this refined and simplified model, the two-dimensional simulation of the polysilicon thin films deposition process in the large-sized tubular low pressure chemical vapor deposition reactor will become more effective and resource efficient. Full article

In recent years, 3D printing has emerged as a promising technology in energy storage, particularly for the fabrication of Li-ion battery electrodes. This innovative manufacturing method offers significant material composition and electrode structure flexibility, enabling more complex and efficient designs. While traditional Li-ion battery fabrication methods are well-established, 3D printing opens up new possibilities for enhancing battery performance by allowing for tailored geometries, efficient material usage, and integrating multifunctional components. This article examines three key 3D printing methods for fabricating Li-ion battery electrodes: (1) material extrusion (ME), which encompasses two subcategories—fused deposition modeling (FDM), also referred to as fused filament fabrication (FFF), and direct ink writing (DIW); (2) material jetting (MJ), including inkjet printing (IJP) and aerosol jet printing (AJP) methods; and (3) vat photopolymerization (VAT-P), which includes the stereolithographic apparatus (SLA) subcategory. These methods have been applied in fabricating substrates, thin-film electrodes, and electrolytes for half-cell and full-cell Li-ion batteries. This discussion focuses on their strengths, limitations, and potential advancements for energy storage applications. Full article