Search Results (7,050)

This study characterizes novel cross-linked polymeric composites based on bisphenol A glycerolate dimethacrylate (BPA.DM) as the primary matrix, incorporating 1-vinyl-2-pyrrolidone (NVP) or 2-hydroxyethyl methacrylate (HEMA) as active diluents, and modified with antimicrobial agents: zinc oxide (ZnO), copper(II) sulfate (CuSO₄), nanosilver (Ag), and benzethonium chloride (BEN). Release kinetics of active components into water and LH medium were measured over 20 days using HPLC (bisphenol A, benzethonium chloride), GF AAS (Cu, Zn, Ag), and GC–MS, revealing highest silver release from HEMA+Ag composites (1671 µg/L), substantial copper release from HEMA (354 mg/L) and NVP (319 mg/L) systems, while benzethonium chloride exhibited significantly lower migration. The effect of NVP- and HEMA-containing composites on the metabolism of the Cerrena unicolor was also assessed. Scanning electron microscopy (SEM) and optical profilometry confirmed extensive surface degradation by C. unicolor mycelium, manifesting as cracks, increased porosity, and altered surface across HEMA- and NVP-based composites after 21-day incubation. Biochemical analysis of the fungus post-culture liquids demonstrated that both composite types markedly enhanced extracellular laccase activity at all tested time points (7, 14, 21 days), with ethanol-sterilized samples inducing a slower-migrating laccase isoform identified via zymography. These materials also increased total protein concentration and superoxide anion radical levels while reducing phenolic compounds relative to controls. The findings demonstrate that antimicrobial-modified BPA.DM composites not only undergo controlled biodegradation by C. unicolor but crucially serve as potential laccase inducers, highlighting their dual utility in bioactive material design and fungal enzyme biotechnology. Full article

The high-rate recycling of scrap steel introduces persistent residual copper (Cu), which accumulates at prior austenite grain boundaries at the surface, during high-temperature reheating, leading to Cu-induced sensitization and deleterious “hot shortness”. To address this, a predictive analytical framework was derived using Fick’s Second Law and the Sekerka, Jeanfils, and Heckel (SJH) approach to model the dissolution of Cu-rich films as a 1D planar moving boundary problem. The validity of this analytical framework was first established through experimentation on controlled Cu-coated steel wire rods, where theoretical concentration profiles showed strong agreement with empirical depth profiles. When applied to a 0.21 wt.% Cu steel at 1000 °C, the model predicted a critical extinction time (t*) of approximately 8.57 min for the complete dissolution of a 20 nm sensitized film. Experimental trials on sensitized wire rods confirmed this prediction, demonstrating an 89% reduction in the frequency of detectable sensitized zones and a significant decrease in zone width following a 10 min thermal dwell. The approach provides a standardized, scalable, and composition-adaptable methodology, grounded in a 1D planar approximation, for optimizing desensitization heat treatments across a range of Cu contents, offering a practical strategy to increase scrap steel utilization while mitigating hot shortness. Full article

Background/Objectives: An ideal bone scaffold should promote bone cell growth and functional vascularization, hence the importance of imbuing biomaterials with pro-angiogenic cues. In this work, silica-based bioactive glasses, either pristine (SBA3) or doped with copper (SBA3_Cu), were embedded in poly(ε-caprolactone) (PCL), which was also used as a control. Methods: In vitro co-cultures of adipose-derived mesenchymal stem/stromal cells (ASCs) and human microvascular endothelial cells (HMEC-1s) were kept in α-MEM, MCDB131, and EndoGRO media to test the biomaterials. The co-cultures were visualized by immunofluorescence and SEM, while flow cytometry was performed to characterize cellular immunophenotype. The angiogenic potential was evaluated using conditioned media of co-cultures to perform a tubulogenesis assay and VEGF-A quantification. Results: Immunophenotypic analysis showed a significant decrease in the endothelial CD31+ cellular subset, whereas the OB-like cellular subset expressing CD105, CD73, CD90, and ALP increased in all culture media over time. In α-MEM, HMEC-1s were unable to form a capillary network independent of the substrates. A more organized network was visible when co-cultures were plated on PCL, in MCDB131 and EndoGRO, or if they were kept in EndoGRO on PCL/SBA3_Cu. The VEGF-A concentrations were similar in the conditioned media from co-cultures grown on PCL/SBA_Cu, in EndoGRO, and on PCL and PCL/SBA3, in MCDB131. Conclusions: The presence of copper did not promote the angiogenic potential of HMEC-1, likely due to the low concentration of released copper ions and the predominant osteoinductive effect of the other ions released by the bioglass. A re-evaluation of formulation and structure of bioglass scaffold could enhance the angiogenic potential. Full article

The copper industry generates nearly 25 million tons of slag annually, which is stockpiled or landfilled, leading to land occupation and the potential for soil and water contamination alongside the environmental burden of the construction sector, which accounts for up to 9% of global CO₂ emissions and massive raw material consumption. The need for low-carbon, resource-efficient binders has spurred interest in geopolymerization, or the alkali activation of aluminosilicate residues, as a pathway to valorize industrial by-products. The objective of this review is to analyze, synthesize, and critically evaluate the scientific evidence on alkali-activated materials derived from Cu slag, emphasizing the synthesis parameters, mechanical and durability behavior, and environmental performance. The review applies the PRISMA 2020 methodology. The analysis of the 57 reports shows that copper slag—used alone or with metakaolin or blast furnace slag—can produce alkali-activated materials with high compressive strength, refined pore structures, and cradle-to-gate CO₂ reductions of up to 80%. Cu slag is not a chemically homogeneous precursor, and its influence on performance depends on the activation strategy and dosage rather than the slag content alone. Overall, this review consolidates dispersed findings, identifies research gaps, and proposes a framework for sustainable valorization in the form of low-carbon construction materials. Full article

Chitosan-based copper composites have attracted considerable interest for biomedical and antimicrobial uses due to their biocompatibility, adjustable dielectric characteristics, and ion-mediated antimicrobial effectiveness. In this study, chitosan films doped with Cu(NO₃)₂, containing 3, 6, and 9 wt% of copper nitrate were produced using a solution-casting method at room temperature. This was done to explore the relationship between structural interactions, dielectric relaxation, optical properties, and antimicrobial efficacy. The resulting composite has been investigated physically using FTIR, XRD, optical analysis, and dielectric spectroscopy, and biologically for its antimicrobial activity. FTIR revealed the molecular structure of Cs-Cu(NO₃)₂ and changes resulting from new bond(s) formation and/or decomposition. XRD indicated that there are no peaks assigned for CuO, which weakens the composite antimicrobial activity. Optical analysis showed an increase in the band gap with copper (II) nitrate concentration over 3%. Additionally, the electrical impedance of the resulting composite increased by approximately one decade. A detailed electrical analysis of the charge-carrier types is provided. Moreover, the antimicrobial activity of chitosan is slightly enhanced by the additive copper (II) nitrate in a dose-dependent manner. The current research offers a mechanistic understanding of the structure–property relationships that govern the behavior of Cu(NO₃)₂–chitosan composites, emphasizing the significant influence of processing conditions on adapting of their dielectric and biological properties. Full article

This study presents a multi-analytical investigation of two Baroque gilded terracotta sculptures—Hercules and the Nemean Lion (Hercules A) and Hercules and the Lernaean Hydra (Hercules B)—attributed to Lorenzo Vaccaro (1655–1706) and preserved at the Museo Civico Gaetano Filangieri in Naples. This research aimed to reconstruct the original manufacturing technique, characterize materials introduced by successive restoration interventions, and identify active degradation mechanisms. A systematic diagnostic approach integrating UV fluorescence imaging, digital optical microscopy, portable energy-dispersive X-ray fluorescence spectroscopy (EDXRF), Raman spectroscopy, Fourier-transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and spectrocolorimetry was applied. The original gilding system—comprising a ferruginous silico-aluminous terracotta substrate, a calcium sulfate ground, a lead-white imprimitura, an iron-rich bole, and a thin gold leaf—is consistent with documented Baroque mission gilding practices in Southern Italy. Analytical evidence further documented extensive non-original interventions, including copper-based artificial patination, bronze powder (porporina) integration, poly (vinyl acetate) adhesives, and acrylic protective coatings. Raman spectroscopy identified the in situ conversion of intentionally applied tenorite (CuO) to malachite (Cu₂CO₃(OH)₂) as an active degradation pathway. Spectrocolorimetric measurements quantified chromatic alterations of up to ΔE = 52 attributable to accumulated surface deposits. The proposed integrated methodology constitutes a replicable diagnostic framework for investigating gilded terracotta artefacts in museum collections. Full article

Waste printed circuit boards (WPCBs) account for approximately 3%–6% of electrical and electronic equipment (WEEE) and contain high concentrations of valuable metals such as copper, often at levels higher than those in natural ores. Consequently, WPCB recycling represents an important opportunity for resource recovery through urban mining and supports the transition toward a circular economy. This study investigates the application of a Falcon centrifugal concentrator for the gravity separation of metallic and non-metallic fractions from WPCBs, with a focus on fine particles below 300 μm. Despite its potential, this method has received little attention, particularly in research. Optimal operating conditions were identified as 80 Hz rotation frequency and 1 LPM water flow rate for particles −100 μm, and 30 Hz rotation frequency and 3 LPM water flow rate for particles in the −300 + 100 μm range. Under these conditions, copper recovery reached 98.25% with Cu content of 10.34% for the coarse fraction and 95.97% with Cu content of 4.47% for the fine fraction after a cleaner stage. The results demonstrate that Falcon gravity concentration is an efficient technique for recovering fine metallic particles and outperforms the multi-gravity separator (MGS). A sustainable beneficiation flowsheet is proposed to enhance metal recovery and reduce environmental impacts. Full article

Precise control of copper electrodeposition is essential for electrochemical additive manufacturing based on layer-by-layer growth. In this work, the influence of selected organic additives, nicotinic acid, benzotriazole, thiourea and urea in sulfate-based electroplating baths was investigated with respect to their applicability in electrodeposition-driven 3D printing. Linear sweep voltammetry (LSV) was used to analyze the electrochemical behavior of Cu(II) reduction, while copper layers were deposited under potentiostatic conditions in a flow-assisted system (potential controlled conditions). The obtained deposits were characterized by SEM/EDS and quantitative measurements of layer thickness and dendrite height. The results show that the additives strongly affect both deposition kinetics and the morphology of electrodeposited layers. Benzotriazole acts as a strong inhibitor, producing fine-grained structures but reducing deposition efficiency and not fully suppressing vertical growth instabilities. Thiourea leads to highly unstable deposition with excessive dendritic growth and increased impurity incorporation. Nicotinic acid enables relatively thick deposits with moderate dendrite formation within an optimal concentration range. In contrast, urea provides the most stable growth, yielding uniform layers with minimal dendritic development and high copper purity. The dendrite height-to-layer thickness ratio proved to be an effective descriptor of electrodeposition growth stability. These findings highlight the critical role of additive selection in optimizing electroplating baths for electrochemical 3D printing applications. Full article

Repurposing mineral processing waste offers both environmental and economic benefits, reducing the disposal burden while enabling mineral resource recovery. A magnetic adsorbent, with an Fe₃O₄ content of 71.0%, collected from waste copper converter slag was utilized to recover gold (Au³⁺) from chloride solution. The adsorbent was separated from the slag samples by crushing, grinding to an average particle size of 30 μm, and magnetic separation. Batch adsorption experiments were performed to evaluate the effects of pH, contact time, chloride concentration, and initial gold concentration on gold uptake amount. The material recovered over 99% of gold from chloride solution under acidic conditions and in the near-neutral pH range. The gold sorption rate was also relatively fast and over 98% recovery was achieved after just 15 min of contact time. Increasing chloride concentration did not influence gold uptake. Parameter studies and spectrometric analyses suggest that chalcocite (Cu₂S) and metallic copper present in magnetite slag reduced the gold chloride complex to metallic gold. These results suggest that converter magnetite slag is a potentially effective sorbent to recover gold from secondary sources due to its selectivity and low cost. Moreover, gold-loaded magnetite slag can be easily separated from the solution by magnetic separation and then recirculated to the smelting stage of copper processing to recover the deposited gold and other precious metals. Overall, this work highlights a pathway to transform waste into opportunity, reinforcing sustainability in mineral processing operations. Full article

To mitigate welding defects in copper wire conductors induced by their high laser reflectivity and thermal conductivity during laser welding, this study combines numerical simulation and experimental testing to investigate the influences of laser processing parameters on the mechanical properties, molten pool dynamic evolution, and microstructural characteristics of copper self-fusion welds and pure Ni powder-filled welds. The results demonstrate that, for self-fusion welding, a moderate increase in laser power and welding time elevates the heat input, which promotes weld penetration and forming quality. The optimal parameter combination (3900 W, 1.0 s) yields a balanced internal densification and grain refinement, with the joint tensile strength reaching a peak of 245 MPa. For Ni powder-filled welding, the infinite solid solubility between Cu and Ni improves interfacial metallurgical bonding. Under the optimal parameters (3500 W, 1.2 s), the joint tensile strength increases to 282 MPa. Heat input exerts a significant effect on the temperature field evolution in both welding processes, yet the molten pool expansion behaviors differ: self-fusion welding exhibits continuous expansion with rising heat input, whereas Ni powder-filled welding displays complex nonlinear variations. Full article

Nanoparticles (NPs) are becoming more commonly used in agricultural practices for cultivating plants under Controlled Environment Agriculture (CEA). The foliar application of copper oxide (CuO) NPs can enhance the production of bioactive compounds in lettuce without adversely affecting yield. However, there is a lack of data regarding the effects of NPs on plants under various lighting conditions, which is a crucial aspect of CEA. The study aims to find out how different lighting conditions can lead to Cu accumulation, to determine the effects of CuO NPs on lettuce growth, antioxidant potential and mineral elements, and to investigate the potential risk of these NPs’ uptake to human health. Plants were grown in Ebb-type hydroponic systems with red-blue and white-red-blue LED lighting at daily light integral 8.64 and 14.4, sprayed with aqueous suspensions of CuO NPs (40 nm, 30 ppm). The influence was determined on lettuce growth, the enzymatic (GR, APX, CAT, SOD, MDHAR, DHAR) and non-enzymatic (TPC, DPPH, ABTS, FRAP) antioxidants, mineral elements and hazard quotients. Our study showed the synergistic effect of foliar application of CuO NPs and lighting on lettuce. We found that CuO NPs positively influenced lettuce growth and stimulated the antioxidant system, particularly the non-enzymatic components such as phenols, carotenoids, and total antioxidant capacity. This effect was enhanced under a broader wavelength range of white-red-blue light and with a higher daily light integral value of 14.4. The application of CuO NPs significantly increased the Cu content in lettuce. Importantly, the concentration of the used CuO NPs did not reach the limit of Cu ions dangerous to humans, as the calculated intake level remained below safe limits, but it is not determined how much of them remained in the form of NPs. Full article

The transition metal copper (Cu) is an essential trace element for humans and serves as a cofactor for numerous enzymes. Therefore, intracellular Cu homeostasis must be tightly regulated. Meanwhile, Cu is increasingly used in industrial and biomedical applications, particularly in nanoparticle (NP) form. However, studies have demonstrated that Cu(II) oxide (CuO) NPs are highly toxic. Therefore, understanding the underlying toxic effects of such compounds is of the utmost importance. In this context, transcriptomic profiling is regarded as a valuable tool. Nevertheless, comparative studies addressing organ-relevant models, such as the liver and lungs, are scarce. Furthermore, no transcriptomic studies have been conducted on human bronchial lung epithelial cells exposed to CuO NPs and Cu²⁺. In this study, we compared the cellular effects of human bronchial lung epithelial cells exposed to both CuO NPs and Cu²⁺ to the effects in human liver cells exposed to Cu²⁺ by applying RNA sequencing. Although cytotoxicity was comparable, we showed that Cu uptake was highly dependent on both the cell type and the form of Cu. The most pronounced concentration-dependent transcriptional changes were observed with CuO NP exposure in BEAS-2B cells. The only differentially expressed genes (DEGs) found by all exposures and treatments were metallothioneins (MTs). The most sensitive targets of Cu-induced toxicity were related to nuclear factor erythroid 2-related factor 2 (NRF2), nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB), and mitogen-activated protein kinase (MAPK) signaling. Furthermore, the effects observed at the transcriptome level were studied at the functional level, such as cell cycle regulation and cytokine release. Thus, we demonstrated that the two cell types differ in susceptibility, and that complementing transcriptome profiling with functional studies provides important mechanistic insights. Full article

Aquaculture is the fastest-growing food production sector, supplying more than half of the world’s seafood and projected to expand further to meet rising global protein demands. Among the various pressures confronting this industry, harmful algal blooms (HABs) rank among the most alarming. Ichthyotoxic flagellates are microalgae known for producing toxins or inducing gill damage that leads to widespread fish mortality. Their increasing frequency poses a critical threat to aquaculture, emphasizing the urgent need for effective and environmentally sustainable strategies to regulate and mitigate these harmful episodes. This study investigated the responses of three ichthyotoxic flagellates renowned for impacting aquaculture operations (Prymnesium parvum, Heterosigma akashiwo, and Fibrocapsa japonica) and tested their susceptibility to two routinely applied chemical agents, hydrogen peroxide (H₂O₂) and copper sulfate (CuSO₄). Mortality, viability, and motility were assessed alongside trajectory-based metrics, including mean squared displacement (MSD) and probability density function (PDF). The results revealed species-specific sensitivities: P. parvum was highly susceptible to H₂O₂, while H. akashiwo and F. japonica were more susceptible to copper toxicity. Ichthyotoxic flagellates exhibited differential sensitivities to chemical treatments, with copper sulfate generally achieving lower EC₅₀ thresholds and greater inhibition of motility than hydrogen peroxide, except in P. parvum. The rapid attenuation of motility at sublethal concentrations highlights swimming behavior as a functional vulnerability, reinforcing the potential for behavior-based mitigation strategies that minimize chemical loading and reduce unintended impacts on cultured fish and surrounding ecosystems. Full article

Aiming at the urgent heat dissipation demands of high-power, high-integration electronic devices, Cu/Al composite heat sinks combine the high thermal conductivity of copper and the lightweight advantage of aluminum, becoming a mainstream solution for advanced thermal management systems. The significant physicochemical differences between Cu and Al, however, make high-quality joining a technical bottleneck. In this study, flux-free ultrasonic brazing with a Zn-based filler metal was used to join 6061 aluminum alloy and industrial pure copper. Gradient heat treatment (55–300 °C) was subsequently applied to systematically investigate its effect on the microstructure, microhardness, and thermal properties of the joints. The results show that the as-brazed joint exhibited excellent bonding (97.3% bonding rate) and shear strength (95.24 MPa). The weld seam consisted of Zn solid solution, Cu solid solution, and Al-Cu-Zn ternary compounds. Heat treatment did not induce new phases but led to the coarsening of Zn-Al-Cu compounds and aggregation of the eutectic structure, reducing grain boundaries. Consequently, the microhardness at the weld center varied non-monotonically, and the thermal conductivity of the joint showed an overall increasing trend with rising heat treatment temperature. This enhancement is attributed to reduced phonon scattering at diminished grain boundaries. This study clarifies the heat treatment–microstructure–thermal properties relationship, providing important guidance for the thermal performance optimization of Cu/Al composite heat sinks. Full article

This work presents a novel one-step plasma–solution synthesis of Prussian Blue (PB) and copper hexacyanoferrate (Cu-PBA) nanoparticles via underwater pulsed DC discharge. For the first time, the direct plasma-assisted formation of these coordination polymers is reported. The obtained materials were examined by X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM). These analyses confirmed that the desired phases had formed, along with small amounts of oxide byproducts (α-Fe₂O₃, CuO) arising from the erosion of the electrodes. Photocatalytic activity was evaluated through the degradation of organic dyes (Reactive Red 6C, Rhodamine B, and Methylene Blue) under UV-light irradiation. Both catalysts achieved complete dye degradation within 90 min of UV irradiation (after an initial 30 min dark adsorption step, total experiment time 120 min). Notably, selective performance was observed: PB exhibited higher activity toward the cationic dye Methylene Blue, while Cu-PBA was more effective for the anionic dye Reactive Red 6C. This selectivity is attributed to the specific oxide impurities forming heterojunctions that facilitate charge separation and generate distinct reactive oxygen species. The plasma–liquid method offers a rapid and environmentally benign route to functional PBA-based composites, with potentially scalable characteristics pending further engineering optimization. These findings highlight the potential of utilizing synthesis-induced impurities to tailor photocatalytic selectivity for water purification applications. Full article