Search Results (816)

Silver-coated copper powder, possessing both excellent electrical conductivity and cost advantages, holds broad application prospects in electronic packaging and conductive materials. This study investigates the surface characteristics of copper powders produced by different methods and the effect of surface modification on electroless silver plating. It also analyses the regulatory role of silver content on coating structure and corrosion resistance. Results indicate varying responses to modifiers among different copper powders: contact angle decreased from 52.9° to 50.3° for physically modified copper powder and from 61.9° to 40.9° for chemically modified copper powder, demonstrating significantly improved surface wettability and enhanced silver layer coverage integrity. As silver content increased from 8 wt% to 15 wt%, the silver layer’s compactness increased, enhancing corrosion resistance. The self-corrosion current densities for physically and chemically modified copper powders decreased from 1.285 × 10⁻⁵ and 1.120 × 10⁻⁵ A·cm⁻² to 4.671 × 10⁻⁶ and 5.075 × 10⁻⁶ A·cm⁻², respectively. At 15 wt% silver content, the emergence of free silver particles on the powder surface led to reduced stability. This study elucidates the synergistic regulation mechanism between the properties of the copper powder matrix and the silver coating content on the silver-coated copper powder structure and its corrosion resistance. It provides experimental evidence for the design and application of high-performance silver-coated copper powders. Full article

In the era of modern technology, tribo coupling components require efficient lubrication to ensure optimal performance, and to avoid significant material loss throughout the entire duty cycle. Solid lubricants, when reinforced with optimal contents, have shown the ability to improve the tribological performance and sustain the lubricious behavior over extended periods. The goal of this study is to improve the reliability and lifetime of tribo components used in a variety of industrial applications. The investigation explores the lubrication mechanisms, and optimizes the tribological behavior of the Ni-based alloy coating impregnated with molybdenum disulfide (MoS₂) and varying contents of silver (Ag). Specifically, four compositions containing 7 wt.% MoS₂ with different contents of Ag, i.e., 5, 10, 15, and 20 wt.%, were developed via the HVOF route and tested from room temperature (RT) to 800 °C. The optimal composition was determined using a parametric experimental optimization approach based on friction and wear minimization. In particular, the coating with 15 wt.% Ag showed the least friction and wear across all tested temperatures. The coating material having 15 wt.% Ag along with 7 wt.% MoS₂ attained a COF of 0.22 and wear rate of 5.3 × 10⁻⁶ mm³/Nm at 800 °C. The optimal content of Ag (15 wt.%) in the coating (NC15) decreased the wear rate by approximately 27% compared to the 20 wt.% Ag variant (NC20) at 800 °C. Overall friction and wear of the derived coatings decreased at 800 °C, with a minor increase at 400 °C. The apparent behavior demonstrated the complex interplay between coating ingredients and testing temperatures. The favorable tribo-chemical reactions and efficient boundary lubrication mechanisms worked together to reduce friction and wear. Full article

Chlorella vulgaris is a microalga with well-established nutritional, antioxidant, anti-inflammatory, and antibacterial potential. The current study aimed to explore the green synthesis of silver nanoparticles (AgNPs) using the ethanolic extract of C. vulgaris and to assess how nanoparticle formation affects the chemical composition, antimicrobial potential, antioxidant capacity, and spasmolytic activity of the extract, building on earlier evidence for its modulatory effects on gastrointestinal smooth muscle. Even though AgNPs from Chlorella have been obtained previously, to the best of our knowledge, their spasmolytic activity has not been evaluated. To assess their properties and stability, ATR-FTIR, TEM images, XRD, DLS, and zeta potential were used. The obtained AgNPs were mostly spherical (with a diameter between 10 and 50 nm) and showed good colloidal stability. The synthesis of AgNPs resulted in significant changes in lipid composition, pigment content, and fatty acid profiles, including a decrease in total chlorophylls and an increase in mono- and polyunsaturated fatty acids. The biosynthesized AgNPs showed moderate to strong antibacterial activity against a variety of Gram-positive and Gram-negative bacteria, yeasts, and fungi. The most pronounced inhibitory effect was observed against A. niger and P. chrysogenum. In ex vivo organ bath experiments, AgNPs modulated the contractile activity and the spasmolytic profile of isolated rat gastric smooth muscle compared with C. vulgaris extract. These results demonstrate that green-synthesized AgNPs present systems with altered smooth muscle activity and improved antibacterial qualities, underscoring their potential for use in functional foods, nutraceuticals, and gastrointestinal therapeutics. Full article

Ag and Cu in biodegradable Zn alloys have been the focus of research due to their biocompatible corrosion products, as well as their ability to improve the mechanical properties of the alloy. In this research, the impact of Ag and Cu on the fluidity of biodegradable Zn alloys was evaluated through the spiral fluidity test. Zn–xAg and Zn–xCu alloys containing Ag or Cu in pure Zn at proportions of 0.5, 1, 2, and 3 wt.% were prepared. In the first stage of the study, the casting temperature to be used in the fluidity tests of the alloys was determined by casting pure Zn at different temperatures. Spiral castings of the alloys were then produced and the fluidity lengths in the spiral channel were measured. Test results showed that the mold filling distances decreased with increasing amounts of Ag and Cu, with Cu causing a stronger reduction than Ag at comparable addition levels. When the Ag content in Zn was raised from 0.5 wt.% to 1 wt.%, a significant reduction in fluidity was observed. Formation of CuZn₅ and ε–AgZn₃ phases in the microstructures was identified as the main factor limiting melt flow. These findings provide insights into how Ag and Cu additions influence the castability of Zn alloys, offering guidance for optimizing alloy composition for biodegradable implant applications. Full article

Background/Objectives: Ash made from juniper trees and added to cornmeal-based dishes may have provided calcium (Ca) to traditional Indigenous diets. Few studies have quantified the mineral content of juniper ash, including its Ca content. The objective of this study was to determine whether juniper ash could serve as a safe source of non-dairy Ca in an intervention study. Methods: Branches from two varieties of Juniper (Rocky Mountain Juniper, or Juniperus scopulorum and Eastern Red Cedar, or Juniperus virginiana) were harvested and burned to ash in a laboratory setting. Juniper ash from the southwestern U.S. available for retail purchase was used for comparison. All samples were tested for content of 10 nutritive elements (Ca, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, selenium, and zinc) and 20 potentially toxic elements (silver, aluminum, arsenic, barium, beryllium, cadmium, cobalt, chromium, mercury, lithium, molybdenum, nickel, lead, antimony, tin, strontium, thallium, uranium, and vanadium) as well as n = 576 pesticide residues. Results: All samples contained both nutritive and potentially toxic elements. Each teaspoon of ash contained an average of 445 ± 141 mg Ca. However, the samples also contained lead in amounts ranging from 1.09 ppm to 15 ppm. Conclusions: Information on the nutritive and potentially toxic elemental content of juniper ash and how it may interact within a food matrix is insufficient to determine its safety as a Ca source. Further investigation is needed on the bioavailability of calcium oxide and its interaction with other dietary components to clarify the potential role of juniper ash in contemporary food patterns. Full article

This study aimed to develop an environmentally friendly composite film with effective antibacterial and preservation properties. Silver nanoparticles (AgNPs) were green-synthesized using grape skin extract as a natural reducing agent and incorporated into a PVA/chitosan matrix. The composition of the extract and the structural characteristics of the AgNPs were characterized by UPLC-MS and TEM. The barrier, mechanical performance, antibacterial, and fruit preservation properties of the resulting films were systematically evaluated. The results showed that the incorporation of AgNPs significantly improved the water vapor and oxygen barrier properties of the film and imparted excellent broad-spectrum antibacterial activity. In grape storage experiments, films with higher AgNPs content effectively delayed skin aging and moisture loss, maintaining better visual quality of the fruit. This work provides a green and feasible approach for the preparation of nanoparticle-enhanced antibacterial packaging materials based on natural products, with promising application potential. Full article

This study evaluates an integrated approach for recovering lead and silver from lead cake through chlorination roasting followed by acid leaching. The lead cake originates from sulfuric acid leaching of zinc ferrite residues obtained during the hydrometallurgical processing of zinc calcine. The effects of roasting temperature, lead cake-to-NaCl mass ratio, and roasting duration on metal recovery were systematically examined to determine optimal process conditions. Based on the experimental results, roasting at 550 °C for 1.5 h with a lead cake-to-NaCl mass ratio of 1:3, followed by leaching in 1 M HCl, was selected as a representative and sufficiently effective condition for the combined process. Under these conditions, nearly complete dissolution of Pb and Ag was achieved, reducing their contents in the final solid residue to 0.90% and 0.0027%, respectively. Compared to direct chloride leaching, the combined process provided higher extraction efficiencies (Pb 98.67%, Ag 98.09%) and a lower final residue mass (34% vs. 45%). The roasting step enables the solid-state conversion of PbSO₄ into highly soluble chloride phases (PbCl₂ and Pb(OH)Cl), while ZnFe₂O₄, Fe₂O₃ and SiO₂ remain stable and form the inert matrix of the residue. Acid leaching at a lower solid-to-liquid ratio (1:10) ensures near-complete dissolution of Pb and Ag, whereas aqueous leaching at a high ratio (1:100) results in incomplete Pb removal. The compliance leaching test (EN 12457-2) confirmed that the residue produced after the optimized two-step treatment meets the EU criteria for inert waste. Overall, the proposed combined process enhances Pb and Ag recovery, minimizes environmental risk, and offers a technically robust and sustainable route for treating lead-containing industrial residues. Full article

Agomelatine (AG) is a novel antidepressant characterized by distinct mechanism of action and minimal side effects. However, extensive first-pass hepatic metabolism limits its clinical efficacy after oral administration, leading to low bioavailability (<5%). To get around these restrictions, the current study set out to create and assess a rectal thermosensitive in situ gel using biosynthesized AG-silver nanoparticles (AG-AgNPs). AG-AgNPs were successfully synthesized with gum acacia as a stabilizing agent, using silver nitrate as a precursor, and ascorbic acid as a reducing agent. The in situ gel formulation was optimized using a 3² factorial design, and then physicochemical, in vitro, and in vivo assessments were conducted. Nanoparticle formation was also evidenced by the appearance of a visible color change, UV-VIS, TEM, and XRD analysis techniques, which depicted spherical-shaped nanoparticles and a crystalline nature. The formulated optimized thermosensitive in situ gel showed good properties, which included drug content of 91.64%, gelation temperature of 26.63 °C, pH of 7.2, gel strength of 36.98 s, and sustained drug release of 80.24% in 6 h. The relative bioavailability in animal studies showed a remarkable increase in systemic availability with 277.5% relative bioavailability in comparison to an oral tablet formulation. In summary, results show that the AG-AgNP-loaded thermosensitive in situ gel could have potential use as a rectal delivery drug for bypassing first-pass effects and improving bioavailability for the drug Agomelatine. Full article

Background/Objectives: The biogenic synthesis of silver nanoparticles (AgNPs) is a promising alternative method, driven by the presence of metabolites in plant matrices capable of acting as reducing and stabilizing agents. Seasonality is a key factor that influences the phytochemical composition of plants and can directly impact the yield, physicochemical characteristics, stability, and bioactivities of the obtained AgNPs. This study aimed to synthesize AgNPs using aqueous extracts from Paullinia cupana leaves collected during dry and rainy seasons, prepared by two different methods (agitation or infusion), to evaluate the impact of these variables on the biosynthesis and properties of the nanostructures. Methods: The extracts were characterized by UHPLC-HRMS/MS, and their total phenolic compound (TPC) content and antioxidant potential against DPPH and ABTS radicals were determined. The AgNPs were characterized by UV/Vis spectrophotometry, dynamic light scattering (DLS), zeta potential (ZP), nano-particle tracking analysis (NTA), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Results: The metabolic profile results showed a predominance of alkaloids and flavonoids in all extracts, with greater phytochemical diversity in samples prepared by infusion. TPC indicated superior phenolic extraction in extracts prepared by infusion during the rainy season, correlating with greater antioxidant potential via the elimination of free radicals. The evolution of AgNP synthesis was accompanied by a gradual change in the color of the suspensions and the formation of plasmon bands between 410 and 430 nm, characteristic of spherical AgNPs. The nanostructures presented hydrodynamic diameters between 37.49 and 145.5 nm, PdI between 0.222 and 0.755, and Zeta potential between −11.3 and −39.9 mV, suggesting satisfactory colloidal stability. Morphological analyses revealed predominantly spherical particles with average diameters ranging from 33.61 to 48.86 nm and uniform distribution, while EDX spectra confirmed the presence of silver. Conclusions: Thus, our results demonstrate that both seasonality and the method of extract preparation influence the phytochemical composition and, consequently, the morphology, stability, and optical properties of AgNPs, with subtle emphasis on collections made during the rainy season and extracts prepared by infusion. Such knowledge contributes to the advancement of more reproducible and purpose-oriented syntheses in the field of green nanotechnology, enabling applications in various sectors. Full article

Alumina (Al₂O₃) reinforced copper matrix composites are widely used in the electronic industry, rail transit, and other fields due to their excellent electrical conductivity, ductility, and wear resistance. However, due to problems such as non-wetting and thermal expansion differences between alumina and Cu, weak interfacial bonding can easily reduce physical and thermal properties. A uniform silver layer was deposited on Al₂O₃ via chemical plating to enhance interface bonding with copper. Al₂O₃@Ag/Cu composites with 1–3 wt.% Al₂O₃ were prepared by rapid hot-press sintering. The effects of plating temperature and Al₂O₃ content on microstructure and properties were investigated. The results show that the optimum coating temperature is 25 °C, and a thin and uniform silver coating can be formed. This effectively improved Al₂O₃–Cu interface bonding while maintaining 77.8% of copper’s thermal conductivity (320.7 W/(m·K)). The composites showed improved wear resistance with increasing Al₂O₃ content. At 3 wt.% Al₂O₃@Ag, the wear rate was 3.36 × 10⁻⁵ mm³/(N·m), 84.4% lower than pure copper, with plow groove wear as the main mechanism. Full article

This paper presents the experimental and computational results characterizing the phase formation of multielement nanoparticles synthesized by the electrically exploding joint-twisted wires. The joint-twisted wires with different element compositions are exploded to investigate the influence of immiscible elements on the phase states of the multielement nanoparticles. The element contents of the multielement nanoparticles deviate from their initial element proportions of the joint-twisted wires due to the non-synchronous exploding process. The silver element enriches the nanoparticle surface, while aluminum, iron, cobalt, and nickel elements show a homogeneous distribution within the nanoparticle. The phase segregation can be adjusted by changing the initial proportion of the silver element in the joint-twisted wires. The decrease in the proportion of silver in joint-twisted wires promotes the homogeneity of silver in the multielement nanoparticles with the phase structure transition from the BCC phase to the FCC phase. A molecular dynamics simulation suggests that both higher initial temperature and more uniform initial mixing conditions facilitate the homogeneous merging of all elements. This study helps with gaining a deep understanding of the phase formation of multielement nanoparticles synthesized by the electrically exploding joint-twisted wires. Full article

Post-industrial heaps are a major environmental problem. They require remediation and reclamation, in which natural succession plays a key role in ecosystem development. This study aimed to assess the effect of heaps formed from materials of different origins on the nutrient content of silver birch (Betula pendula Roth), a pioneer species in this process. We analyzed nutrient contents in biomass fractions (fine and coarse roots, stemwood, bark, coarse and fine branches, leaves) and in soils sampled from 0 to 10, 10 to 20, 20 to 40, and 40 to 80 cm. Basic soil properties and the contents of N, P, K, Ca, Mg, S, Fe, Mn, Cu, and Zn in both soil and biomass were determined. The soils were poor in total organic carbon and differed in pH, texture, and nutrient status. Leaves and roots contained the highest nutrient contents, whereas stemwood contained the lowest. Statistical analyses revealed significant differences in all studied elements between heaps. Among macronutrients, N, P, and Mg were most abundant, followed by K, Ca, and S. Among micronutrients, Mn dominated, followed by Fe, Zn, and Cu. Findings underscore that silver birch growing on contaminated post-industrial heaps cannot be considered a hyperaccumulator of trace elements. Full article

Wildfires are becoming more frequent in Central Europe, raising questions about the mechanical and chemical integrity of fire-affected conifer wood. Because commercial species such as silver fir (Abies alba), Norway spruce (Picea abies), and Scots pine (Pinus sylvestris) are not evolutionarily adapted to fire, their thermo-mechanical response remains poorly quantified. This study investigates oven-dry density, static bending strength, compressive strength parallel to the grain, Brinell hardness, chemical composition, elemental composition, and heat of combustion of wood collected from a recent post-fire stand in Poland. Fire exposure resulted in a slight reduction in oven-dry density, while compressive and bending strengths increased relative to reported reference values, likely due to moisture depletion and partial thermal modification of cell-wall polymers. Chemical analyses showed moderate thermally induced shifts, including higher lignin and carbon content with depth, consistent with progressive carbonization of the affected tissues. Although surface-affected wood retained measurable mechanical capacity and energy value, its structural applicability remains constrained by potential brittleness and the limited sampling depth. These findings provide essential baseline data for evaluating post-fire conifer wood and its potential use in low-grade material and bioenergy applications. Full article

Numerous commercial products are used in poultry farms to maintain water quality and prevent pathogen dispersion, but their actual impact on broiler chicks’ performance and gut health remains underreported. This study aimed to investigate the effects of three commercial poultry water disinfectants on broiler chicks’ performance and the physicochemical characteristics of gastrointestinal content when continuously added to drinking water. A total of 144 one-day-old Ross^® 308 broiler chicks were randomly allocated into four treatment groups: Group A (negative control), Group B (0.01–0.025% v/v Product A [H₂O₂ + silver complex]), Group C (0.01–0.04% v/v Product B [H₂O₂ + peracetic acid]), and Group D (0.05–0.1% w/v Product C [peroxides]). Body weight (BW) was measured weekly, while average daily weight gain (ADWG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were calculated for different time periods. Additionally, on days 15 and 40, the pH of the crop, gizzard, duodenum, jejunum, and cecum contents was assessed, while the viscosity of jejunal and ileal contents were also measured. Statistical analysis revealed that all water disinfectants significantly (p ≤ 0.05) reduced BW, ADWG, and ADFI during the early growth phase, followed by either recovery or stabilization in the later stages. Drinking water disinfectants induced significant changes in intestinal physicochemical parameters, including reductions in pH of the content in the jejunum (p ≤ 0.05) during early growth and increased gizzard pH (p ≤ 0.05) and digesta viscosity (p ≤ 0.05) at later ages. These findings suggest that continuous water disinfection can suppress broiler chicks’ performance during the early stages of growth while significantly altering the physicochemical characteristics of gastrointestinal content. Further research is needed to investigate the mechanism that underlaying these results and optimize dosage schemes that balance pathogen control with the health, welfare, and performance of broilers. Full article

There is limited understanding regarding the potential toxicity of nano-silver to crayfish. This study aims to evaluate the histopathological changes, oxidative stress, transcriptomics, and intestinal microbiota changes in different tissues of crayfish after exposure to nano-silver. The results showed that exposure to nano-silver caused pathological changes in the muscles, hepatopancreas, and gills of crayfish. Damage to muscular tissue progressively worsened with increasing concentrations of nano-silver, leading to a gradual widening of the gaps between muscle fibers. Nano-silver enlarged hepatopancreatic lumen and epithelial vacuolation, while the structure of the gills became disorganized, with severe damage to the gill membranes. The activities of peroxidase (CAT), superoxide dismutase (SOD), and glutathione reductase (GSH), as well as the content of malondialdehyde (MDA) in the muscles, hepatopancreas, and gills, were altered due to nano-silver exposure. Furthermore, along with the alteration of intestinal flora, there were alterations in the diversity of intestinal microbiota, an increase in the abundance of Bacteroides and Ca_Bacilloplasma, and a decrease in the abundance of Citrobacter. The abundance of harmful bacteria increased, causing intestinal inflammatory damage. Totals of 1549 and 1305 differently expressed genes (DEG) were found in the muscles and hepatopancreas, according to transcriptome analysis. Significantly affected pathways included the PPAR signaling pathway. These findings provide valuable insights into the use of nano-silver in the aquaculture of crayfish. Full article