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Compared to conventional metal oxide nanoparticles, metal oxide nanocomposites have demonstrated significantly enhanced efficiency in various applications. In this study, we aimed to synthesize zinc oxide–copper oxide nanocomposites (ZnO-CuO NCs) using a green synthesis approach. The synthesis involved mixing 4 g of Zn(NO3)2·6H2O with different concentrations of mangosteen (G. mangostana) leaf extract (0.02, 0.03, 0.04 and 0.05 g/mL) and 2 or 4 g of Cu(NO3)2·3H2O, followed by calcination at temperatures of 300, 400 and 500 °C. The synthesized ZnO-CuO NCs were characterized using various techniques, including a UV-Visible spectrometer (UV-Vis), photoluminescence (PL) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) analysis and Field Emission Scanning Electron Microscope (FE-SEM) with an Energy Dispersive X-ray (EDX) analyzer. Based on the results of this study, the optical, structural and morphological properties of ZnO-CuO NCs were found to be influenced by the concentration of the mangosteen leaf extract, the calcination temperature and the amount of Cu(NO3)2·3H2O used. Among the tested conditions, ZnO-CuO NCs derived from 0.05 g/mL of mangosteen leaf extract, 4 g of Zn(NO3)2·6H2O and 2 g of Cu(NO3)2·3H2O, calcinated at 500 °C exhibited the following characteristics: the lowest energy bandgap (2.57 eV), well-defined Zn-O and Cu-O bands, the smallest particle size of 39.10 nm with highest surface area-to-volume ratio and crystalline size of 18.17 nm. In conclusion, we successfully synthesized ZnO-CuO NCs using a green synthesis approach with mangosteen leaf extract. The properties of the nanocomposites were significantly influenced by the concentration of the plant extract, the calcination temperature and the amount of precursor used. These findings provide valuable insights for researchers seeking innovative methods for the production and utilization of nanocomposite materials.

Although copper oxide high-temperature superconductors constitute a complex and diverse material family, they all share a layered lattice structure. This curious fact prompts the question of whether high-temperature superconductivity can exist in an isolated monolayer of copper oxide, and if so, whether the two-dimensional superconductivity and various related phenomena differ from those of their three-dimensional counterparts. The answers may provide insights into the role of dimensionality in high-temperature superconductivity. Here we develop a fabrication process that obtains intrinsic monolayer crystals of the high-temperature superconductor Bi 2 Sr 2 CaCu 2 O 8+ δ (Bi-2212; here, a monolayer refers to a half unit cell that contains two CuO 2 planes). The highest superconducting transition temperature of the monolayer is as high as that of optimally doped bulk. The lack of dimensionality effect on the transition temperature defies expectations from the Mermin–Wagner theorem, in contrast to the much-reduced transition temperature in conventional two-dimensional superconductors such as NbSe 2 . The properties of monolayer Bi-2212 become extremely tunable; our survey of superconductivity, the pseudogap, charge order and the Mott state at various doping concentrations reveals that the phases are indistinguishable from those in the bulk. Monolayer Bi-2212 therefore displays all the fundamental physics of high-temperature superconductivity. Our results establish monolayer copper oxides as a platform for studying high-temperature superconductivity and other strongly correlated phenomena in two dimensions. Transport and scanning tunnelling microscopy studies of freestanding monolayers of an unconventional layered copper oxide establish that the superconducting properties of copper oxides are not changed in the 2D limit.

Copper and Copper oxide nanoparticles have garnered a lot of attention among the metal oxide nanoparticles, especially because of their many characteristics and applications in many disciplines, notably nanomedicine and biomedical sciences. We have covered all of the conceivable green production techniques of copper/copper oxide nanoparticles in this review. This manuscript also diagrammatically depicts the exact mechanism of all conceivable biosynthetic routes. We also look at the antibacterial, antifungal, antiviral, and anticancer properties of biosynthesized copper/copper oxide nanoparticles, as well as their effects on plant growth, nutrition, and defense mechanism.

Mycosynthesis of nanoparticle (NP) production is a potential ecofriendly technology for large scale production. In the present study, copper oxide nanoparticles (CuONPs) have been synthesized from the live cell filtrate of the fungus Penicillium chrysogenum. The created CuONPs were characterized via several techniques, namely Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). Furthermore, the biosynthesized CuONPs were performed against biofilm forming Klebsiella oxytoca ATCC 51,983, Escherichia coli ATCC 35,218, Staphylococcus aureus ATCC 25,923, and Bacillus cereus ATCC 11,778. The anti-bacterial activity result was shown with the zone of inhibition determined to be 14 ± 0.31 mm, 16 ± 0.53 mm, 11 ± 0.57 mm, and 10 ± 0.57 mm respectively. Klebsiella oxytoca and Escherichia coli were more susceptible to CuONPs with minimal inhibitory concentration (MIC) values 6.25 and 3.12 µg/mL, respectively, while for Staphylococcus aureus and Bacillus cereus, MIC value was 12.5 and 25 μg/mL, respectively. The minimum biofilm inhibition concentration (MBIC) result was more evident, that the CuONPs have excellent anti-biofilm activity at sub-MIC levels reducing biofilm formation by 49% and 59% against Klebsiella oxytoca and Escherichia coli, while the results indicated that the MBIC of CuONPs on Bacillus cereus and Staphylococcus aureus was higher than 200 μg/mL and 256 μg/mL, respectively, suggesting that these CuONPs could not inhibit mature formatted biofilm of Bacillus cereus and Staphylococcus aureus in vitro. Overall, all the results were clearly confirmed that the CuONPs have excellent anti-biofilm ability against Klebsiella oxytoca and Escherichia coli. The prepared CuONPs offer a smart approach for biomedical therapy of resistant microorganisms because of its promoted antimicrobial action, but only for specified purposes.

More than 30 years after the discovery of high-temperature superconductivity in copper oxides, its mechanism remains a mystery. Electron pairing mediated solely by lattice vibrations—phonons—is thought to be insufficient to account for the high transition temperatures. He et al. found a rapid and correlated increase of the superconducting gap and electron-phonon interactions as the chemical composition of their bismuth-based cuprate samples was varied across a critical doping concentration. The interplay of electron-phonon with electron-electron interactions may lead to enhanced transition temperatures. Science , this issue p. 62 Angle-resolved photoemission uncovers an interplay between various types of interaction in a cuprate superconductor. Electron-boson coupling plays a key role in superconductivity for many systems. However, in copper-based high–critical temperature ( T c ) superconductors, its relation to superconductivity remains controversial despite strong spectroscopic fingerprints. In this study, we used angle-resolved photoemission spectroscopy to find a pronounced correlation between the superconducting gap and the bosonic coupling strength near the Brillouin zone boundary in Bi 2 Sr 2 CaCu 2 O 8+δ . The bosonic coupling strength rapidly increases from the overdoped Fermi liquid regime to the optimally doped strange metal, concomitant with the quadrupled superconducting gap and the doubled gap-to- T c ratio across the pseudogap boundary. This synchronized lattice and electronic response suggests that the effects of electronic interaction and the electron-phonon coupling (EPC) reinforce each other in a positive-feedback loop upon entering the strange-metal regime, which in turn drives a stronger superconductivity.

Versatile nature of copper oxide nanoparticles (CuO NPs) has made them an imperative nanomaterial being employed in nanomedicine. Various physical, chemical, and biological methodologies are in use for the preparation of CuO NPs. The physicochemical and biological properties of CuO NPs are primarily affected by their method of fabrication; therefore, selectivity of a synthetic technique is immensely important that makes these NPs appropriate for a specific biomedical application. The deliberate use of CuO NPs in biomedicine questions their biocompatible nature. For this reason, the present review has been designed to focus on the approaches employed for the synthesis of CuO NPs; their biomedical applications highlighting antimicrobial, anticancer, and antioxidant studies; and most importantly, the in vitro and in vivo toxicity associated with these NPs. This comprehensive overview of CuO NPs is unique and novel as it emphasizes on biomedical applications of CuO NPs along with its toxicological assessments which would be useful in providing core knowledge to researchers working in these domains for planning and conducting futuristic studies.Key Points• The recent methods for fabrication of CuO nanoparticles have been discussed with emphasis on green synthesis methods for different biomedical approaches.• Antibacterial, antioxidant, anticancer, antiparasitic, antidiabetic, and antiviral properties of CuO nanoparticles have been explained.• In vitro and in vivo toxicological studies of CuO nanoparticles exploited along with their respective mechanisms.

Background Copper oxide (CuO) nanoparticles (NPs) are known to trigger cytotoxicity in a variety of cell models, but the mechanism of cell death remains unknown. Here we addressed the mechanism of cytotoxicity in macrophages exposed to CuO NPs versus copper chloride (CuCl 2 ). Methods The mouse macrophage cell line RAW264.7 was used as an in vitro model. Particle uptake and the cellular dose of Cu were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The deposition of Cu in lysosomes isolated from macrophages was also determined by ICP-MS. Cell viability (metabolic activity) was assessed using the Alamar Blue assay, and oxidative stress was monitored by a variety of methods including a luminescence-based assay for cellular glutathione (GSH), and flow cytometry-based detection of mitochondrial superoxide and mitochondrial membrane potential. Protein aggregation was determined by confocal microscopy using an aggresome-specific dye and protein misfolding was determined by circular dichroism (CD) spectroscopy. Lastly, proteasome activity was investigated using a fluorometric assay. Results We observed rapid cellular uptake of CuO NPs in macrophages with deposition in lysosomes. CuO NP-elicited cell death was characterized by mitochondrial swelling with signs of oxidative stress including the production of mitochondrial superoxide and cellular depletion of GSH. We also observed a dose-dependent accumulation of polyubiquitinated proteins and loss of proteasomal function in CuO NP-exposed cells, and we could demonstrate misfolding and mitochondrial translocation of superoxide dismutase 1 (SOD1), a Cu/Zn-dependent enzyme that plays a pivotal role in the defense against oxidative stress. The chelation of copper ions using tetrathiomolybdate (TTM) prevented cell death whereas inhibition of the cellular SOD1 chaperone aggravated toxicity. Moreover, CuO NP-triggered cell death was insensitive to the pan-caspase inhibitor, zVAD-fmk, and to wortmannin, an inhibitor of autophagy, implying that this was a non-apoptotic cell death. ZnO NPs, on the other hand, triggered autophagic cell death. Conclusions CuO NPs undergo dissolution in lysosomes leading to copper-dependent macrophage cell death characterized by protein misfolding and proteasomal insufficiency. Specifically, we present novel evidence for Cu-induced SOD1 misfolding which accords with the pronounced oxidative stress observed in CuO NP-exposed macrophages. These results are relevant for our understanding of the consequences of inadvertent human exposure to CuO NPs.

The nature of the pseudogap phase of the copper oxides (‘cuprates’) remains a puzzle. Although there are indications that this phase breaks various symmetries, there is no consensus on its fundamental nature 1 . Fermi-surface, transport and thermodynamic signatures of the pseudogap phase are reminiscent of a transition into a phase with antiferromagnetic order, but evidence for an associated long-range magnetic order is still lacking 2 . Here we report measurements of the thermal Hall conductivity (in the x – y plane, κ xy ) in the normal state of four different cuprates—La 1.6− x Nd 0.4 Sr x CuO 4 , La 1.8− x Eu 0.2 Sr x CuO 4 , La 2− x Sr x CuO 4 and Bi 2 Sr 2− x La x CuO 6+ δ . We show that a large negative κ xy signal is a property of the pseudogap phase, appearing at its critical hole doping, p *. It is also a property of the Mott insulator at p  ≈ 0, where κ xy has the largest reported magnitude of any insulator so far 3 . Because this negative κ xy signal grows as the system becomes increasingly insulating electrically, it cannot be attributed to conventional mobile charge carriers. Nor is it due to magnons, because it exists in the absence of magnetic order. Our observation is reminiscent of the thermal Hall conductivity of insulators with spin-liquid states 4 – 6 , pointing to neutral excitations with spin chirality 7 in the pseudogap phase of cuprates. The so-called pseudogap phase in hole-doped cuprate superconductors is associated with an unusually large thermal Hall effect that attains unprecedented levels as the parent Mott insulator is approached.

In the past couple of years, hybrid nanofluids have garnered substantial attention due to their augmented flow and thermal properties. When such fluids propagate through a pipe, they reveal characteristics that make them applicable in a variety of different fields for geothermal energy extraction. Hence, this article presents a discussion on the behavior of hybrid nanofluid flow using a model based on third-grade sodium alginate. Sodium alginate has the potential to be used in the extraction of geothermal energy. To investigate the current flow, two kinds of nanoparticles are proposed: zinc oxide (ZnO) and copper oxide (CuO). Additionally, the effects of electric and magnetic fields are taken into consideration in the current flow. The fully evolved, incompressible fluid is moving through a pipe. The energy equation takes into consideration a variety of factors, including viscous dissipation and joule heating. The homotopy perturbation approach is used for obtaining the series solutions of nonlinear differential equations (DEs). The resultant differential equations have been solved up to third-order solutions. It is worth concluding that the electric field and the thermal Grashof number significantly impact the velocity profile, resulting in a solid symmetrical pattern. The nanoparticles increased the fluid’s viscosity, perhaps slowing it down. The integration of nanoparticles decreases the amount of the thermal profile over the whole pipe. Still, when copper oxide nanoparticles are absent, the thermal profile is at its most considerable magnitude. The pressure decreases equally impact the velocity and thermal properties.

The use of metal and metal oxide nanoparticles is frequently regarded as a potential solution to the issue of bacterial antibiotic resistance. Among the proposed range of nanoparticles with antibacterial properties, copper oxide nanoparticles are of particular interest. Although the antibacterial properties of copper have been known for a considerable period of time, studies on the effects of copper oxide nanomaterials with respect to biological systems have attracted considerable attention in recent years. This review presents a summary of the antibacterial properties of copper oxide nanoparticles, the mechanisms by which the antibacterial effect is realized, and the key reported methods of modifying these nanoparticles to improve their antibacterial activity. A comparative analysis of the effectiveness of these nanoparticles is presented depending on the type of microorganism, the shape of the nanoparticles, and the Gram classification of bacteria based on data from published sources. In addition, the review addresses the biological activities of copper oxide nanoparticles, including their antifungal and cytotoxic properties, as well as their “antioxidant” activity. According to the conducted analysis of the literature data, it can be concluded that copper oxide nanoparticles have a significant bacteriostatic potential with respect to a wide range of microorganisms and, in some cases, contribute to the inhibition of fungal growth. At the same time, the sensitivity of Gram-positive bacteria to the effect of copper oxide nanoparticles was often higher than that of Gram-negative bacteria.