Search Results (232)

Interpreting multispectral remote sensing data for hydrothermal alteration mapping remains challenging in complex mountainous metallogenic belts because dense pixel-level field labels are difficult to obtain and weak spectral responses are affected by lithological background, vegetation, snow/ice cover, and topographic shadow. This study proposes a principal component analysis (PCA)-guided weakly supervised workflow for mapping hydroxyl- and iron-oxide-related spectral anomalies in the Bulong–Maidan–Tuoyun gold–copper metallogenic belt, southwestern Tianshan, China, using Landsat 8 Operational Land Imager (OLI) imagery. PCA was used as a spectral prior to generate PCA-derived positive spectral anomaly samples for model training. A Residual-ECA Alteration Information Extraction (REA-AIE) model was developed to refine PCA-derived anomalies by learning local spectral–spatial features from multispectral image patches. Under the PCA-constrained random sample-level evaluation, REA-AIE achieved F1 scores of 95.90% and 97.09% for hydroxyl- and iron-oxide-related spectral anomalies, respectively; these values indicate agreement with PCA-derived pseudo-labels rather than spatially independent estimates of mapping performance. Petrography-constrained site-level assessment showed that REA-AIE-predicted spectral anomalies occurred within 90 m of 43 of the 53 altered sites, corresponding to a site-level recall of 81.13% and supporting their consistency with field-based geological evidence. Full article

Silicone elastomers are attractive matrices for transdermal drug delivery systems, but the controlled release of poorly water-soluble drugs from hydrophobic silicone networks remains challenging. Medical-grade silicone elastomers are generally regarded as chemically stable, biologically inert, and highly biocompatible polymer matrices, which supports their use in biomedical and pharmaceutical materials. Here, ibuprofen-loaded silicone/polyol composite films were prepared from hydroxyl-terminated polydimethylsiloxane (PDMS-OH) using glycerol- and 1,2-propylene glycol-derived alkoxysilane cross-linkers and amino-terminated PDMS as a metal-free room-temperature-vulcanising catalyst. The effects of cross-linker composition, glycerol, PEG 200 and selected functional additives on film formation, morphology, apparent ibuprofen release and preliminary Strat-M^® permeation were evaluated. FTIR analysis indicated no covalent reaction between ibuprofen and the silicone network, but suggested hydrogen-bonding interactions with polyol-rich domains, particularly in glycerol-containing systems. Raman mapping supported ibuprofen incorporation within the films, while SEM showed phase-separated microdomains whose morphology depended on the formulation. Apparent release into 0.9% NaCl at 37 °C was formulation-dependent over 72 h. The optimised F-9 film showed approximately 83% cumulative apparent release, whereas the F-10 film containing copper oxide nanoparticles and sea buckthorn oil showed the highest numerical cumulative apparent release, approximately 94%. Kinetic analysis of the apparent release data supported a mainly diffusion-controlled contribution, modulated by hydrophilic microdomains. These results provide preliminary materials-development evidence that silicone/polyol films can be used to tune apparent ibuprofen release and merit further optimisation for local topical or transdermal applications; however, efficient skin permeation and biological performance require dedicated validation. Full article

The chemical form of copper is a key determinant of metal bioavailability and may profoundly influence cyanobacterial metabolism and the biological activity of culture-derived products. In this study, Nostoc linckia was cultivated in the presence of metallic copper nanoparticles (CuNPs), copper oxide nanoparticles (CuONPs), or CuSO₄·5H₂O (15 mg Cu L⁻¹). Biomass productivity, biochemical composition, and antioxidant capacity, together with the physicochemical and biochemical characteristics of the culture liquid, were determined. The culture liquid was subsequently evaluated through the seed priming of four maize (Zea mays L.) hybrids. The different copper forms induced distinct metabolic responses in Nostoc linckia. CuONPs promoted biomass accumulation while maintaining protein and photosynthetic pigment contents and inducing an adaptive oxidative response, whereas CuNPs, and particularly CuSO₄, impaired biomass production and primary metabolism. These metabolic changes were reflected in the culture liquid properties and were associated with genotype-dependent differences in maize germination dynamics, seedling vigor, and biochemical composition. Integrated correlation, hierarchical clustering, and principal component analyses revealed coordinated relationships linking cyanobacterial physiology, culture liquid profiles, and plant responses. Collectively, these findings demonstrate that the chemical form of copper drives metabolic remodeling in Nostoc linckia, thereby shaping the biochemical composition and biostimulant properties of its culture liquid. Full article

Electrochemical CO₂ reduction reactions (CO₂RR) offer a viable approach to mitigating anthropogenic CO₂ while simultaneously generating value-added chemicals. Among diverse electrocatalyst classes, metal–organic framework (MOF)-based materials have been extensively explored owing to their excellent tunability of chemical structure, high surface area, and the ability to tailor the coordination/electronic environment of active centers. This state-of-the-art review provides a critical assessment of recent progress in the development of pristine Cu-based MOFs, Cu MOF-derived catalysts, and hybrid Cu@MOFs for the selective production of C₁ products such as CO, CH₄, and formate/formic acid. Theoretical investigations into the roles of the copper center, ligands, pore structures, and interfacial effects reveal that product selectivity is influenced by more than just the oxidation state of Cu sites. Mixed-valence Cu⁺/Cu⁰ junctions, defect-rich surfaces, conductive frameworks, and coordination site tuning constitute fundamental design strategies for steering CO₂ reduction pathways. In addition to electrocatalytic performance, this review emphasizes the importance of life cycle assessment (LCA). Current studies identify electricity demand, separation steps, and operational lifetime as the dominant environmental impact factors in LCA analyses. Combining molecular-level catalyst design with systems-level sustainability considerations, this review highlights key challenges and future prospects for advancing Cu-MOF electrocatalysts toward efficient and sustainable C₁ formation from CO₂. Full article

This study focuses on the synthesis of Co_0.5Cu_0.5Fe₂O₄ mixed ferrites supported on nanoporous carbon materials. The carbon supports were derived from two mixtures: a mixture of spent motor oil and pine wood chips (designated as AC-A), and a mixture of spent motor oil and crushed coal obtained from the Chukurovo mine (designated as AC-B). Additionally, two types of carbon components—nanodiamond and graphene oxide—were used for the synthesis of nanosized ceria-based hybrid nanocomposites. The results revealed that the active phase deposited on the carbon supports consists of a complex mixture of finely dispersed ferrite nanoparticles as well as small CeO₂ crystallites in the case of hybrid nanocomposites. The dispersion and phase composition of the deposited copper–cobalt ferrites depends on the textural properties of the carbon supports. Among the investigated materials, the graphene oxide-modified composites exhibited the highest catalytic activity at 670 K, achieving a methanol conversion of 90%. Full article

Efficient photocatalytic degradation of azo dyes requires coordinated control of nanostructure, surface chemical environment, and interfacial charge transport. In this work, rare-earth-modified copper-oxalate-derived CuO nanostructures (RE = Ce, Sm, Er, Tm, and Yb) were prepared through hydrothermal synthesis of a copper oxalate precursor, followed by calcination and ultrasonic-assisted RE modification. Structural, spectroscopic, optical, and electrochemical analyses show RE-associated apparent lattice perturbation, modified surface oxygen environments, stronger visible-region optical responses, higher apparent majority-carrier-density descriptors, and lower fitted interfacial charge-transfer resistance relative to pristine CuO. Among the samples, Ce-CuO exhibited the best performance, with a band gap of 1.48 eV, an apparent majority-carrier density of (1.94 ± 0.04) × 10²¹ cm⁻³, and a charge-transfer resistance of 216 Ω·cm². It achieved 91.59% methyl orange (MO) decolorization within 9 min under simulated solar irradiation, corresponding to a 23.7-fold higher apparent rate constant than pristine CuO, and retained 75.8% decolorization efficiency after eight cycles. Scavenger experiments suggested that h⁺ was the principal oxidative species under the investigated conditions, while ·OH and ·O₂⁻ also contributed to MO transformation. Overall, the results show that rare-earth modification is associated with changes in the structural, surface-chemical, optical, and interfacial electrochemical characteristics of copper-oxalate-derived CuO photocatalysts. Full article

Thyroid hormone synthesis involves several key steps culminating in the organification of iodide into iodothyronines, thyroxine, and triiodothyronine. To date, there is no clear mechanistic evidence of extrathyroidal iodothyronine synthesis. Upon iodine (KI/I₂) loading, human neutrophils produced significant amounts of de novo iodothyronines as determined by diagnostic immunoassay and LCMS/MS. Treatment of neutrophils with sodium iodide resulted in a lower hormone yield, which was enhanced following the addition of copper chloride to culture media. The appearance of thyroid hormones was observed only after induction of the oxidative burst with PMA. Synthesis of hormones was abolished by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, DPI. Essential components for iodothyronine synthesis included hydrogen peroxide, myeloperoxidase, and either serum or thyroglobulin serving as an iodination substrate. In a series of novel experiments, we show a serine protease requirement for liberation of thyroid hormones from reservoirs of iodinated proteins. Serine proteases, proteinase K, and neutrophil-derived elastase, but not cysteine protease cathepsin B, released thyroxine from in vitro iodinated or native thyroid-derived thyroglobulin, respectively. Our studies show that neutrophil-mediated iodothyronine synthesis is an extracellular, multi-step, enzymatic process initiated upon cellular activation, but is independent of neutrophil viability window. Overall, this report presents a series of cellular and enzymatic experiments demonstrating the induction of thyroid hormones by non-classical mechanisms that can potentially regulate localized levels of iodothyronines. Full article

The persistent residue of antibiotics in aquatic environments and the subsequent global spread of antibiotic resistance (AMR) pose major threats to ecological security and public health. Advanced oxidation processes based on peroxymonosulfate (PMS) activation, which generate highly reactive species such as sulfate radicals, hydroxyl radicals, singlet oxygen, and high-valent metal-oxo species, have shown remarkable potential for the advanced treatment of antibiotic-contaminated wastewater. In recent years, copper-based single-atom catalysts (Cu SACs), featuring atomically dispersed active centers, nearly 100% atomic utilization, and highly tunable coordination microenvironments, have emerged as a research frontier in PMS activation. This review systematically summarizes the current status of antibiotic pollution and associated eco-health risks, and comprehensively discusses the main synthesis strategies for Cu SACs (e.g., MOF-pyrolysis, salt-assisted templating, nanoconfinement, multi-site synergistic systems, and biomass-derived methods) as well as structural characterization techniques. It focuses on the regulation mechanisms of PMS activation pathways through precise chemical strategies including coordination number regulation, heteroatom doping (S, P, etc.), axial/second-shell coordination engineering, and atomic inter-site spacing modulation. The competitive and synergistic relationships among radical, singlet oxygen, high-valent copper-oxo, and electron transfer pathways are systematically analyzed. Furthermore, this review evaluates the intrinsic activity, selectivity, wide pH adaptability, mineralization efficiency, catalyst stability, and performance in real water matrices for antibiotic degradation by Cu SACs. Finally, it highlights the key scientific challenges and future directions, including the precise construction of single-atom-cluster synergistic systems, integration of in situ/operando characterization with multiscale simulation, scalable synthesis and engineering lifetime validation, machine-learning-assisted high-throughput rational design, and holistic control of environmental risks throughout the treatment chain. Full article

Plant-pathogenic bacteria threaten crop productivity and quality, yet chemical options remain limited compared with those for fungal and oomycete diseases. Current management relies mainly on copper bactericides, limited antibiotics, induced-resistance agents, biocontrol and resistant cultivars. However, copper and streptomycin resistance, efflux-mediated multidrug tolerance and rapid pathogen adaptation have weakened these strategies. Target-oriented research provides a framework for exploring agricultural antibacterials, anti-virulence agents, anti-colonization strategies, resistance sensitizers and host-resistance interventions, but many of these approaches remain conceptual, model-system, greenhouse or medical-bacteriology-derived rather than proven field solutions. This review classifies bacterial control targets into two interconnected groups: growth-essential targets, including peptidoglycan biosynthesis, membrane/envelope systems, nucleic-acid processes, protein synthesis, metabolism, nutrient transport and cell division; and anti-virulence/anti-adaptation targets, including secretion systems, quorum sensing, biofilms, motility, adhesion, cell-wall-degrading enzymes, tolerance systems, oxidative-stress responses and host susceptibility factors. Using “Candidatus Liberibacter asiaticus” (CLas) as a case study, genome annotation and infection-stage transcript-abundance data prioritized Sec-dependent secretion, outer-membrane/surface proteins, Bam assembly, nutrient transporters, Clp proteostasis, redox adaptation and core cellular processes as candidate target classes. Envelope-associated, secretion/anti-virulence, nutrient-acquisition and stress-sensitization modules may represent potential directions for downstream validation, but CLas candidates remain hypothesis-generating priorities requiring validation for essentiality, conservation, druggability, delivery feasibility, crop safety and field performance. Full article

Background/Objectives: Ceratonia siliqua L. (carob) is a rich source of bioactive compounds with potential health-promoting properties. This study investigated the kinetics of serum metabolites following the consumption of a carob beverage and evaluated associated changes in circulating antioxidant status. Methods: Fifteen apparently healthy adult men completed an acute postprandial intervention; only male participants were included to minimize the biological variability related to sex-dependent differences in phytochemical kinetics and antioxidant responses. Participants consumed a beverage from carob pod powder (30 g) dispersed in water (200 mL). Blood samples were collected at baseline and every 30 min for 6 h following intake. Serum metabolic profiling was performed using a non-targeted liquid chromatography–time-of-flight mass spectrometry (LC-TOF-MS) approach. Antioxidant responses were assessed by measuring ferric-reducing antioxidant power (FRAP) and serum resistance to copper sulphate-induced oxidation. Results: Twenty-four putative metabolites were detected, including phenolic compounds, fatty acids, amino acids, dipeptides, monosaccharides, pyridoxine, and gut microbiota-derived metabolites. Urolithin B appeared at 30 min (28.0 ± 4.0 × 10² a.u.), while p-cresol sulfate increased from 53.3 ± 6.5 × 10² a.u. at baseline to 130.0 ± 7.0 × 10² a.u. at 30 min. FRAP values did not change significantly over time (p = 0.332), whereas oxidation lag time showed a significant time effect (p = 0.001), reaching its highest mean at 180 min (9093.5 ± 1885.1 s). Conclusions: Carob beverage consumption resulted in a diverse postprandial serum metabolite profile. Antioxidant responses appeared to be only partly explained by circulating phenolics, suggesting that additional pathways and bioactive constituents may contribute. Full article

Copper oxide (CuO) is a narrow-bandgap p-type semiconductor promising for visible-light photocatalysis, yet it suffers from rapid charge recombination and low carrier transfer efficiency. In this study, two distinct CuO photocatalysts were fabricated via different routes: two-dimensional CuO nanosheets derived from annealing a CuBDC metal–organic framework (MOF) precursor, and oriented one-dimensional CuO nanoflower arrays prepared by electrochemical deposition, followed by annealing. The crystal structure, morphology, optical absorption, and photoelectrochemical properties were systematically characterized by XRD, SEM, XPS, UV-Vis spectroscopy, transient photocurrent response, EIS, and PL spectroscopy. The CuO nanoflower thin film exhibits a broad visible-light absorption, a markedly higher photocurrent density (42.25 μA cm⁻²), and lower charge-transfer resistance compared to CuO nanosheets. When evaluated for visible-light photocatalytic degradation of methylene blue (MB), rhodamine B (RhB), and malachite green (MG), the CuO thin film completely degraded MB within 15 min, with an apparent rate constant of 20.15 h⁻¹—approximately three times that of CuO nanosheets. It also showed 1.2- and 1.28-fold higher activity for RhB and MG, respectively. The enhanced performance is attributed to the oriented nanoflower architecture that provides continuous charge transport pathways, suppresses carrier recombination, and extends light propagation via multiple reflections. This work demonstrates that microstructural engineering is an effective strategy to overcome the intrinsic limitations of CuO photocatalysts for wastewater treatment. Full article

The mineral system model formalizes the critical geological processes and mappable parameters that control ore formation, which can then be translated into spatial predictors used as input features in machine learning (ML)-based mineral prospectivity mapping (MPM). In most MPM studies, exploration evidence features are indeed derived from the mineral system model of the targeted deposit type. However, not all features produced in this way are necessarily informative or favorable for prospectivity analysis. This challenge can be addressed by using feature selection frameworks to identify the most relevant features before applying ML and deep learning (DL) algorithms for mathematical integration. To address this need, this study employs an unsupervised variational autoencoder (VAE) framework to evaluate and rank exploration evidence layers. The VAE quantifies feature importance through a systematic strategy that measures the sensitivity of reconstruction-error components, mean squared error (MSE), mean absolute error (MAE), and Kullback–Leibler (KL) divergence, to individual feature variations. In this way, the VAE ranks the exploration features and helps to identify those that are the most useful for prospectivity mapping. The proposed approach was applied to a real geo-dataset from a porphyry copper district in Iran. Based on the conceptual model of porphyry copper mineralization, 15 evidence layers were generated, including proximity to phyllic, argillic, propylitic, iron oxide, and silicification alteration zones; proximity to intrusive rocks, faults, and fault intersections; and geochemical maps of Cu, Mo, Sb, Pb, Zn, As, and W. The VAE-based ranking indicated that evidence layers related to hydrothermal alterations, intrusive rocks, and faults were the most influential exploration features, whereas geochemical evidence layers showed lower relative importance. Based on this evaluation, two modeling scenarios were considered: in the first, all available features were used, and in the second, only the features selected by the VAE framework were included. In both cases, the final prospectivity model was produced by an autoencoder (AE). For comparison, the prediction-area (P–A) plots of the two prospectivity models were generated using 14 known mineral occurrences as positive ground-truth labels, indicating that the model based on the selected features achieved a higher prediction rate (80%) than the model based on all features (72%). These results demonstrate that the evidence layers derived from the mineral system approach can benefit from unsupervised VAE-based evaluation, leading to improved performance of the prospectivity modeling. Full article

The development of sustainable electrocatalysts for clean energy by modifying biomass-derived activated carbon with nitrogen and transition metals is presented. Activated carbon (AWC) material was obtained using alder wood char as a precursor, while nitrogen and cobalt or copper nanoparticles were incorporated with the aim of creating efficient materials for hydrazine oxidation (HzOR) and direct hydrazine–hydrogen peroxide fuel cells (DHHPFC, N₂H₄–H₂O₂). The composition, structure, and surface morphology of the created materials were examined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The activity of the AWC, AWC–Co–N, and AWC–Cu–N catalysts for HzOR was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). N₂H₄–H₂O₂ fuel-cell tests were performed by applying the catalysts as both the anode and cathode. It was found that all materials retained a hierarchical porous carbon framework, while metal incorporation altered surface compactness. Cobalt doping produced well-dispersed Co nanoparticles and abundant Co–N–C coordination sites, whereas Cu introduction resulted in moderately compact structures with uniformly distributed Cu-based nanoparticles. Electrochemical measurements demonstrated that both metal dopants enhanced HzOR activity, with the catalytic performance following the order of AWC–Co–N > AWC–Cu–N > AWC. Fuel-cell testing further confirmed this trend: AWC–Co–N achieved the highest maximum power density (30.4 mW cm⁻²), outperforming AWC–Cu–N (17.7 mW cm⁻²). These results identify AWC–Co–N as a highly effective bifunctional electrocatalyst for DHHPFCs. Full article

The development of low-cost and highly sensitive electrochemical sensing platforms for pesticide monitoring has attracted significant attention in recent years. In this study, coke-derived carbon (CDC) was successfully synthesized from petroleum coke through high-temperature carbonization under a nitrogen atmosphere. Subsequently, a CDC@CuO-NP nanocomposite was fabricated by depositing copper oxide nanoparticles onto the CDC matrix. The morphology, structure, and elemental composition of the synthesized materials were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and elemental mapping analyses, confirming the successful formation of the composite and the uniform distribution of CuO nanostructures on the carbon surface. Electrochemical characterization demonstrated that the incorporation of CuO significantly enhanced the electrochemical performance of CDC by increasing the electroactive surface area and facilitating electron transfer. The CDC@CuO-NP-modified glassy carbon electrode was applied for the electrochemical detection of dichlorvos (DDVP) using electrochemical impedance spectroscopy (EIS). The sensor exhibited a concentration-dependent increase in charge-transfer resistance and showed a linear response in the concentration range of 247–3770 nM, with the regression equation y = 47.1458C + 111.8162 and a correlation coefficient of R² = 0.9832. The developed sensor achieved a low limit of detection (LOD) of 2.3 nM, demonstrating high sensitivity toward DDVP. These results indicate that the CDC@CuO-NP nanocomposite is a promising, low-cost, and efficient electrode material for the sensitive determination of organophosphorus pesticides and has considerable potential for environmental monitoring and food safety applications. Full article

Polyphenolic compounds extracted from Taraxacum officinale (dandelion) were used as natural chelating ligands to synthesize copper–polyphenol complexes, which were subsequently immobilized on sericite to obtain hybrid organic–inorganic materials. The complexes were prepared under controlled pH and temperature conditions, yielding structures with different Cu–polyphenol ratios. Structural characterization confirmed the formation of Cu(II)–polyphenol chelates, partial reduction to Cu(I) species at higher pH values, and the deposition of mixed Cu₂O/CuO phases on the layered sericite substrate. Copper–polyphenol superstructures, copper nanoparticles, and copper oxide crystallites were heterogeneously distributed depending on synthesis conditions and metal–ligand ratios. The hybrid materials exhibited modified optical properties, combining the intrinsic reflectance of sericite with UV absorption from polyphenols and copper species. When incorporated into an emulsion matrix, the materials showed promising UV-screening performance, with SPF-equivalent values ranging from 7 to 33 depending on concentration. Antimicrobial evaluation demonstrated that copper–polyphenol complexes displayed enhanced activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Candida albicans compared to the natural extract, while sericite-supported hybrids retained selective efficacy, particularly against Gram-positive bacteria and C. albicans. These results indicate the potential of dandelion-derived copper complexes and their sericite hybrids as multifunctional bioactive agents for cosmetic dermatology applications. Full article