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Search Results (241)

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Keywords = La2CuO4

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24 pages, 70177 KiB  
Article
Geology, Structure, Geochemistry, and Origin of Iron Oxide Deposits in Dehbid, Southwest Iran
by Abdorrahman Rajabi, Reza Nozaem, Sara Momenipour, Shojaedin Niroomand, Shahrokh Rajabpour, Somaye Rezaei, Pura Alfonso, Carles Canet, Ahmad Kazemi Mehrnia, Pouria Mahmoodi, Amir Mahdavi, Mansoor Kazemirad, Omid Laghari Firouzjaei and Mohammad Amini
Minerals 2025, 15(6), 590; https://doi.org/10.3390/min15060590 - 30 May 2025
Viewed by 921
Abstract
The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a [...] Read more.
The Dehbid region, located in the southern part of the Sanandaj–Sirjan Zone (SSZ), is a significant iron oxide mining district with over 20 iron oxide deposits (IODs) and reserves of up to 50 million tons of iron oxide ores. The region features a NW–SE oriented ductile shear zone, parallel to the Zagros thrust zone, experienced significant deformation. Detailed structural studies indicate that the iron mineralization is primarily stratiform to stratabound and hosted in late Triassic to early Jurassic silicified dolomites and schists. These ore deposits consist of lenticular iron oxide orebodies and exhibit various structures and textures, including banded, laminated, folded, disseminated, and massive forms of magnetite and hematite. The Fe2O3 content in the mineralized layers varies from 30 to 91 wt%, whereas MnO has an average of 3.9 wt%. The trace elements are generally low, except for elevated concentrations of Cu (up to 4350 ppm) and Zn (up to 3270 ppm). Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis of magnetite reveals high concentrations of Mg, Al, Si, Mn, Ti, Cu, and Zn, with significant depletion of elements such as Ga, Ge, As, and Nb. This study refutes the hypothesis of vein-like or hydrothermal genesis, providing evidence for a sedimentary origin based on the trace element geochemistry of magnetite and LA-ICP-MS geochemical data. The Dehbid banded iron ores (BIOs) are thought to have formed under geodynamic conditions similar to those of BIOs in back-arc tectonic settings. The combination of anoxic conditions, submarine hydrothermal iron fluxes, and redox fluctuations is essential for the formation of these deposits, suggesting that similar iron–manganese deposits can form during the Phanerozoic under specific geodynamic and oceanographic conditions, particularly in tectonically active back-arc environments. Full article
(This article belongs to the Special Issue Mineralogy and Geochemistry of Polymetallic Ore Deposits)
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16 pages, 2310 KiB  
Article
Prediction and Screening of Lead-Free Double Perovskite Photovoltaic Materials Based on Machine Learning
by Juan Wang, Yizhe Wang, Xiaoqin Liu and Xinzhong Wang
Molecules 2025, 30(11), 2378; https://doi.org/10.3390/molecules30112378 - 29 May 2025
Viewed by 642
Abstract
The search for stable, lead-free perovskite materials is critical for developing efficient and environmentally friendly energy solutions. In this study, machine learning methods were applied to predict the bandgap and formation energy of double perovskites, aiming to identify promising photovoltaic candidates. A dataset [...] Read more.
The search for stable, lead-free perovskite materials is critical for developing efficient and environmentally friendly energy solutions. In this study, machine learning methods were applied to predict the bandgap and formation energy of double perovskites, aiming to identify promising photovoltaic candidates. A dataset of 1053 double perovskites was extracted from the Materials Project database, with 50 feature descriptors generated. Feature selection was carried out using Pearson correlation and mRMR methods, and 23 key features for bandgap prediction and 18 key features for formation energy prediction were determined. Four algorithms, including gradient-boosting regression (GBR), random forest regression (RFR), LightGBM, and XGBoost, were evaluated, with XGBoost demonstrating the best performance (R2 = 0.934 for bandgap, R2 = 0.959 for formation energy; MAE = 0.211 eV and 0.013 eV/atom). The SHAP (Shapley Additive Explanations) analysis revealed that the X-site electron affinity positively influences the bandgap, while the B″-site first and third ionization energies exhibit strong negative effects. Formation energy is primarily governed by the X-site first ionization energy and the electronegativities of the B′ and B″ sites. To identify optimal photovoltaic materials, 4573 charge-neutral double perovskites were generated via elemental substitution, with 2054 structurally stable candidates selected using tolerance and octahedral factors. The XGBoost model predicted bandgaps, yielding 99 lead-free double perovskites with ideal bandgaps (1.3~1.4 eV). Among them, four candidates are known compounds according to the Materials Project database, namely Ca2NbFeO6, Ca2FeTaO6, La2CrFeO6, and Cs2YAgBr6, while the remaining 95 candidate perovskites are unknown compounds. Notably, X-site elements (Se, S, O, C) and B″-site elements (Pd, Ir, Fe, Ta, Pt, Cu) favor narrow bandgap formation. These findings provide valuable guidance for designing high-performance, non-toxic photovoltaic materials. Full article
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15 pages, 13896 KiB  
Article
Critical Metal Potential of Tasmanian Greisen: Lithium, Rare Earth Elements, and Bismuth Distribution and Implications for Processing
by Julie Hunt, Jeffrey Oalmann, Mohamed Aâtach, Eric Pirard, Russell Fulton and Sandrin Feig
Minerals 2025, 15(5), 462; https://doi.org/10.3390/min15050462 - 29 Apr 2025
Cited by 1 | Viewed by 565
Abstract
Typical greisen-type ore samples from northeastern Tasmania were investigated for their critical metal potential. The samples contain zinnwaldite (KLiFe2+Al(AlSi3O10)(F,OH)2), a lithium-bearing mica that is prone to excessive breakage during conventional processing, leading to the generation [...] Read more.
Typical greisen-type ore samples from northeastern Tasmania were investigated for their critical metal potential. The samples contain zinnwaldite (KLiFe2+Al(AlSi3O10)(F,OH)2), a lithium-bearing mica that is prone to excessive breakage during conventional processing, leading to the generation of very-fine-sized particles (i.e., slimes, <20 µm), eventually ending up in tailings and resulting in lithium (Li) loss. To assess whether the natural grain size of valuable minerals could be preserved, the samples were processed using electric pulse fragmentation (EPF). The results indicate that EPF preferentially fragmented along mica-rich veins, maintaining coarse grain sizes, although a lower degree of liberation was observed in fine-grained, massive samples. In addition, the critical metal distribution within zinnwaldite was examined using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) techniques. The results reveal differences in Li content between groundmass zinnwaldite and vein-hosted zinnwaldite and that the zinnwaldite contains the critical elements rubidium (Rb), cesium (Cs), and rare earth elements (REEs: La, Ce, Pr, and Nd). Vein-hosted zinnwaldite has a higher average Li content, whereas groundmass mica contains higher concentrations of Rb, Cs, and REEs. Both mica types host inclusions of bismuth–copper–thorium–arsenic (Bi-Cu-Th-As), which are more abundant in vein-hosted mica. In some of the samples, Bi, Cu, Th, and REEs also occur along the mica cleavage planes, as well as in mineral inclusions. The Li, Rb, and Cs grades are comparable to those of European deposits, such as Cínovec and the Zinnwald Lithium Project. Full article
(This article belongs to the Special Issue Microanalysis Applied to Mineral Deposits)
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8 pages, 3501 KiB  
Communication
Angle-Engineered Bi0.94La0.06CuSeO Thin Films for High-Performance Transverse Thermoelectric Devices
by Mingjing Chen, Chenming Yue, Tianchang Qin, Haixu Liu, Guoying Yan and Shufang Wang
Sensors 2025, 25(9), 2791; https://doi.org/10.3390/s25092791 - 29 Apr 2025
Viewed by 378
Abstract
BiCuSeO has emerged as a highly promising material for transverse thermoelectric (TTE) applications, with its performance significantly enhanced through La doping. In this study, we investigate the effect of inclination angle on the TTE performance of inclined Bi0.94La0.06CuSeO thin [...] Read more.
BiCuSeO has emerged as a highly promising material for transverse thermoelectric (TTE) applications, with its performance significantly enhanced through La doping. In this study, we investigate the effect of inclination angle on the TTE performance of inclined Bi0.94La0.06CuSeO thin films fabricated using the pulsed laser deposition technique. A huge output voltage of 31.4 V was achieved in the 10° inclined Bi0.94La0.06CuSeO film under 308 nm ultraviolet pulsed laser irradiation. Furthermore, the films also exhibited significant response with excellent linearity when exposed to continuous-wave lasers across a broad spectral range (360 nm to 10,600 nm) and a point-like heat source. Notably, the voltage is directly proportional to sin2θ, where θ is the inclination angle. These findings not only provide a clear optimization strategy for TTE performance through inclination angle engineering but also highlight the material’s great potential for developing high-performance optical and thermal sensing TTE devices. Full article
(This article belongs to the Section Nanosensors)
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15 pages, 4158 KiB  
Article
The Effect of Surfactant P123 on the KCuLaZrO2 Catalysts in the Direct Conversion of Syngas to Higher Alcohols
by Jiaqian Yang, Jiayu Jin, Duomei Xue, Lifei Zhi, Zhongqiang Wang and Kai Sun
Catalysts 2025, 15(5), 431; https://doi.org/10.3390/catal15050431 - 28 Apr 2025
Viewed by 600
Abstract
The direct conversion of coal-based syngas to HA (higher alcohols) is of great significance, but it remains challenging stemming from the complexity of the reaction and the difficulty in regulating the alcohol distribution. P123, as a structure-directing agent, is of great [...] Read more.
The direct conversion of coal-based syngas to HA (higher alcohols) is of great significance, but it remains challenging stemming from the complexity of the reaction and the difficulty in regulating the alcohol distribution. P123, as a structure-directing agent, is of great significance for the preparation of mesoporous materials with specific pore sizes and pore structures. Therefore, a series of KCLZ-xP (KCuLaZrO2-xP123) catalysts with varying P123 contents were prepared via the coprecipitation method and applied for HA synthesis. The KCLZ-30P catalyst exhibits a high CO conversion of 63.1%, a C2+OH/MeOH ratio of 0.98, and a comparable STYROH (space-time yield of total alcohol). Notably, it can selectively form linear alcohols in HAS while suppressing the formation of i-C4 (branched alcohols). The results show that P123 remarkably boosts catalytic activity through enlarging the specific surface area and facilitating the generation of t-ZrO2. Simultaneously, P123 suppresses the formation of i-C4 alcohols by reducing the number of basic sites and weakening the strength of high-strength basic sites. Remarkably, the abundant CHx and non-dissociated CO adsorbed on Cu0 facilitate the CO insertion process, thereby enhancing the C-C chain growth capability in linear alcohols, particularly favoring the formation of ethanol. These findings may offer the potential designing efficient catalysts for HAS (higher alcohol synthesis) from syngas. Full article
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26 pages, 6113 KiB  
Article
Geochemical Characteristics of Organic-Enriched Shales in the Upper Ordovician–Lower Silurian in Southeast Chongqing
by Changqing Fu, Zixiang Feng, Chang Xu, Xiaochen Zhao and Yi Du
Minerals 2025, 15(5), 447; https://doi.org/10.3390/min15050447 - 26 Apr 2025
Cited by 1 | Viewed by 352
Abstract
A variety of variables, such as organic matter input, redox conditions, depositional rates, and terrigenous input, affect the deposition of black shale. Furthermore, because of the significant regional variations in paleodepositional environments, these factors have a complex role in organic matter enrichment. Global [...] Read more.
A variety of variables, such as organic matter input, redox conditions, depositional rates, and terrigenous input, affect the deposition of black shale. Furthermore, because of the significant regional variations in paleodepositional environments, these factors have a complex role in organic matter enrichment. Global geological events influenced sedimentary conditions, organic enrichment, and the development of organic-enriched shales during the Late Ordovician to Early Silurian. The Wufeng–Longmaxi Formation black shales in Southeastern Chongqing were analyzed for X-ray diffraction (XRD), major and trace element geochemistry, and total organic carbon (TOC) data; this led to further analysis of the relationship between the depositional environment and organic matter aggregation and rock type evolution. The primary minerals found in the Wufeng–Longmaxi shale are quartz, feldspar, carbonatite (calcite and dolomite), and clay. The high index of compositional variability (ICV) values (>1) and the comparatively low chemical index of alteration (CIA) values (52.6–72.8) suggest that the sediment source rocks are juvenile and are probably experiencing weak to moderate chemical weathering. The selected samples all show negative Eu anomalies, flat heavy rare earth elements, and mildly enriched light rare earth elements. The ratios of La/Th, La/Sc, Th/Sc, ΣREE-La/Yb, TiO2-Ni, and La/Th-Hf suggest that acidic igneous rocks were the main source of sediment, with minor inputs from ancient sedimentary rocks. The correlations of paleoclimate proxies (Sr/Cu, CIA), redox proxies (V/Cr, V/Ni, V/(V + Ni), Ni/Co, U/Th), paleoproductivity proxies (Baxs, CuEF, NiEF), and water mass restriction proxies (Mo/TOC, UEF, MoEF) suggest a humid–semiarid, anoxic, moderate–high paleoproductivity, and moderate–strongly restricted environment. On the basis of the aforementioned interpretations, the paleoenvironment of the Wufeng–Longmaxi Formations was established, with paleoredox conditions and restricted water masses likely being the primary factors contributing to organic matter enrichment. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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23 pages, 8291 KiB  
Article
Cu1Ni2/Al2O3 Catalyst from Its Hydrotalcite Precusor with Highly Active Sites for Efficient Hydrogenation of Levulinic Acid Toward 2-Methyltetrahydrofuran
by Jie Qin, Guohong Chen, Kaiqi Zheng, Jiajun Wu, Fanan Wang, Xueping Liu and Rengui Weng
Catalysts 2025, 15(5), 416; https://doi.org/10.3390/catal15050416 - 23 Apr 2025
Viewed by 446
Abstract
2-Methyltetrahydrofuran (2-MTHF), a hydrogenated derivative of levulinic acid (LA), is a biomass-derived platform compound with diverse and significant applications as a biofuel, gasoline additive, green solvent, and pharmaceutical synthesis intermediate. This study investigates the preparation of a Cu1Ni2/Al2 [...] Read more.
2-Methyltetrahydrofuran (2-MTHF), a hydrogenated derivative of levulinic acid (LA), is a biomass-derived platform compound with diverse and significant applications as a biofuel, gasoline additive, green solvent, and pharmaceutical synthesis intermediate. This study investigates the preparation of a Cu1Ni2/Al2O3 catalyst through the calcination–reduction of CuNiAl hydrotalcite as a precursor, which was subsequently utilized in the hydrogenation of LA to produce 2-MTHF. The calcination–reduction process applied to CuNiAl hydrotalcite results in a lattice confinement effect. This method not only disperses the active metal sites but also alters the bonding patterns of the active metals, thereby enhancing the activity and stability of the Cu1Ni2/Al2O3 catalyst. The results indicate that complete conversion of LA and a 2-MTHF yield of 87.6% can be achieved under optimal conditions of 190 °C, 5 MPa hydrogen, and a reaction time of 5 h, demonstrating an efficient one-step conversion process. Additionally, the catalyst’s recyclability was assessed through multiple reuse tests, with a loss of activity of only 9.2% after six cycle experiments, suggesting its feasibility and reliability for industrial applications. Full article
(This article belongs to the Section Catalytic Materials)
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17 pages, 16145 KiB  
Article
Conversion of Levulinic Acid to γ-Valerolactone Using Hydrotalcite-Derived Cu-Ni Bimetallic Catalyst
by Shikang Zhao, Guohong Chen, Kaiqi Zheng, Shaojie Li, Jiaqi Xu, Fanan Wang, Xueping Liu and Rengui Weng
Processes 2025, 13(4), 1110; https://doi.org/10.3390/pr13041110 - 7 Apr 2025
Viewed by 606
Abstract
γ-Valerolactone (GVL) is a promising bio-based platform molecule with significant potential for energy applications. The production of GVL via biomass-based levulinic acid (LA) is an important reaction. To enhance the conversion and selectivity of non-precious-metal catalysts in the LA-to-GVL process and to better [...] Read more.
γ-Valerolactone (GVL) is a promising bio-based platform molecule with significant potential for energy applications. The production of GVL via biomass-based levulinic acid (LA) is an important reaction. To enhance the conversion and selectivity of non-precious-metal catalysts in the LA-to-GVL process and to better understand the key factors influencing this conversion, we conducted a series of experiments. In this study, supported Cu-Ni bimetallic catalysts (Cu-Ni2/Al2O3) were prepared using layered double hydroxides (LDHs) as a precursor. Compared with Cu-Ni catalysts synthesized via the conventional impregnation method, the Cu-Ni2/Al2O3 catalysts exhibit higher catalytic activity and stability. The results demonstrated that efficient conversion was achieved with isopropanol as the hydrogen donor solvent, a reaction temperature of 180 °C, and a reaction time of 1 h. The yield of GVL reached nearly 90%, with a decrease of approximately only 6% after six consecutive cycles. The Cu-Ni2/Al2O3 catalyst proved to be effective for converting biomass-derived LA to GVL, offering a route that not only reduces production costs and environmental impact but also enables efficient biomass-to-energy conversion. Full article
(This article belongs to the Section Catalysis Enhanced Processes)
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20 pages, 4493 KiB  
Article
Copper Molybdate-Catalyzed Esterification of Levulinic Acid: A Heterogeneous Approach for Biofuel Synthesis
by Alyne Pereira de Oliveira Ribeiro, Wyvirlany Valente Lobo, Talles André Feitosa de Carvalho, José Milton Elias de Matos, Flávio Augusto de Freitas, Yurimiler Leyet Ruiz, Robert S. Matos, Ştefan Ţălu, Henrique Duarte da Fonseca Filho, Lianet Aguilera Domínguez, Walter Ricardo Brito and Francisco Xavier Nobre
Catalysts 2025, 15(4), 357; https://doi.org/10.3390/catal15040357 - 6 Apr 2025
Cited by 1 | Viewed by 742
Abstract
The catalytic esterification of levulinic acid (LA) to methyl levulinate (ML) was investigated using copper molybdate (Cu3(MoO4)2(OH)2) as a heterogeneous catalyst. The catalyst, synthesized via chemical precipitation, exhibited a monoclinic structure with self-assembled nanoplates forming [...] Read more.
The catalytic esterification of levulinic acid (LA) to methyl levulinate (ML) was investigated using copper molybdate (Cu3(MoO4)2(OH)2) as a heterogeneous catalyst. The catalyst, synthesized via chemical precipitation, exhibited a monoclinic structure with self-assembled nanoplates forming spherical mesostructures. Structural characterization confirmed its high crystallinity, while textural analysis revealed a BET surface area of 70.55 m2 g−1 with pore sizes in the nanometric range (1–6 nm). The catalytic performance was systematically evaluated under varying reaction conditions, including temperature, catalyst dosage, reaction time, methanol-to-LA molar ratio, alcohol type, and catalyst reusability. Optimal conversion of 99.3% was achieved at 100 °C, a 1:20 methanol-to-LA molar ratio, 5% catalyst loading, and a reaction time of 4 h. Comparative analysis with other heterogeneous catalysts demonstrated superior efficiency and stability of Cu3(MoO4)2(OH)2, with minimal activity loss over four reuse cycles (final conversion of 77.1%). Mechanistic insights suggest that its high activity is attributed to Lewis and Brønsted acid sites, facilitating efficient esterification. This study underscores the potential of copper molybdate as a sustainable and recyclable catalyst for biofuel additive synthesis, advancing green chemistry strategies for biomass valorization. Full article
(This article belongs to the Special Issue Sustainable Catalysis for Green Chemistry and Energy Transition)
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28 pages, 6120 KiB  
Article
Machine Learning Classification of Fertile and Barren Adakites for Refining Mineral Prospectivity Mapping: Geochemical Insights from the Northern Appalachians, New Brunswick, Canada
by Amirabbas Karbalaeiramezanali, Fazilat Yousefi, David R. Lentz and Kathleen G. Thorne
Minerals 2025, 15(4), 372; https://doi.org/10.3390/min15040372 - 2 Apr 2025
Cited by 1 | Viewed by 758
Abstract
This study applies machine learning (ML) techniques to classify fertile [for porphyry Cu and (or) Au systems] and barren adakites using geochemical data from New Brunswick, Canada. It emphasizes that not all intrusive units, including adakites, are inherently fertile and should not be [...] Read more.
This study applies machine learning (ML) techniques to classify fertile [for porphyry Cu and (or) Au systems] and barren adakites using geochemical data from New Brunswick, Canada. It emphasizes that not all intrusive units, including adakites, are inherently fertile and should not be directly used as the heat source evidence layer in mineral prospectivity mapping without prior analysis. Adakites play a crucial role in mineral exploration by helping distinguish between fertile and barren intrusive units, which significantly influence ore-forming processes. A dataset of 99 fertile and 66 barren adakites was analyzed using seven ML models: support vector machine (SVM), neural network, random forest (RF), decision tree, AdaBoost, gradient boosting, and logistic regression. These models were applied to classify 829 adakite samples from around the world into fertile and barren categories, with performance evaluated using area under the curve (AUC), classification accuracy, F1 score, precision, recall, and Matthews correlation coefficient (MCC). SVM achieved the highest performance (AUC = 0.91), followed by gradient boosting (0.90) and RF (0.89). For model validation, 160 globally recognized fertile adakites were selected from the dataset based on well-documented fertility characteristics. Among the tested models, SVM demonstrated the highest classification accuracy (93.75%), underscoring its effectiveness in distinguishing fertile from barren adakites for mineral prospectivity mapping. Statistical analysis and feature selection identified middle rare earth elements (REEs), including Gd and Dy, with Hf, as key indicators of fertility. A comprehensive analysis of 1596 scatter plots, generated from 57 geochemical variables, was conducted using linear discriminant analysis (LDA) to determine the most effective variable pairs for distinguishing fertile and barren adakites. The most informative scatter plots featured element vs. element combinations (e.g., Ga vs. Dy, Ga vs. Gd, and Pr vs. Gd), followed by element vs. major oxide (e.g., Fe2O3T vs. Gd and Al2O3 vs. Hf) and ratio vs. element (e.g., La/Sm vs. Gd, Rb/Sr vs. Hf) plots, whereas major oxide vs. major oxide, ratio vs. ratio, and major oxide vs. ratio plots had limited discriminatory power. Full article
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22 pages, 9031 KiB  
Article
Characterizing the Behavior and Microstructure of Cu-La2O3 Composite Processed via Equal Channel Angular Pressing
by Lenka Kunčická and Radim Kocich
Metals 2025, 15(4), 368; https://doi.org/10.3390/met15040368 - 27 Mar 2025
Viewed by 425
Abstract
Cu-based alloys and composites are popular to prepare electroconductive parts. However, their processing can be challenging, especially in case of composites strengthened with oxides. To save the necessary time and costs, numerical simulations can be of help when determining the deformation behaviour of [...] Read more.
Cu-based alloys and composites are popular to prepare electroconductive parts. However, their processing can be challenging, especially in case of composites strengthened with oxides. To save the necessary time and costs, numerical simulations can be of help when determining the deformation behaviour of (newly introduced) materials. The study presents a combined method of strengthening of Cu by adding 5 wt.% of La2O3 particles and performing shear-based deformation by equal channel angular pressing (ECAP). The effects of the method on the microstructure, mechanical properties, and thermal stability of the composite are examined both numerically and experimentally. The results showed that the La2O3 addition caused the maximum imposed strain to be higher for the composite than for commercially pure Cu, which led to the development of subgrains and shear bands within the microstructure, and a consequent increase in microhardness. The numerical predictions revealed that the observed differences could be explained by the differences in the material plastic flow (comparing the composite to commercially pure Cu). The work hardening supported by the addition of La2O3 led to a significant increase in stress and punch load during processing, as well as contributed to a slight increase in deformation temperature in the main deformation zone of the ECAP die. Certain inhomogeneity of the parameters of interest across the processed workpiece was observed. Nevertheless, such inhomogeneity is typical for the ECAP process and steps prospectively leading to its elimination are proposed. Full article
(This article belongs to the Special Issue Design and Development of Metal Matrix Composites)
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17 pages, 2893 KiB  
Article
Anti-Virulence Properties of Curcumin/CuO-NPs and Their Role in Accelerating Wound Healing In Vivo
by Amr M. Shehabeldine, Bahaa M. Badr, Fathy M. Elkady, Toru Watanabe, Mostafa A. Abdel-Maksoud, Abdulaziz M. Alamri, Salman Alrokayan and Amer M. Abdelaziz
Medicina 2025, 61(3), 515; https://doi.org/10.3390/medicina61030515 - 17 Mar 2025
Viewed by 715
Abstract
Background and Objectives: This study introduces an innovative approach to accelerating wound healing by leveraging the bactericidal properties of mycosynthesized copper oxide nanoparticles (CuO-NPs) and their combination with curcumin against Pseudomonas aeruginosa. The study aims to evaluate their antimicrobial efficacy, impact [...] Read more.
Background and Objectives: This study introduces an innovative approach to accelerating wound healing by leveraging the bactericidal properties of mycosynthesized copper oxide nanoparticles (CuO-NPs) and their combination with curcumin against Pseudomonas aeruginosa. The study aims to evaluate their antimicrobial efficacy, impact on quorum sensing-associated virulence factors, and potential therapeutic applications in wound healing. Materials and Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CuO-NPs were determined to be 25 μg/mL and 50 μg/mL, respectively. At sub-inhibitory concentrations (0.5 MIC, 0.25 MIC, and 0.125 MIC), their effects on P. aeruginosa growth and quorum sensing-associated virulence factors were assessed. Antioxidant activity and cytotoxicity were also evaluated. Additionally, the combination of CuO-NPs and curcumin (CUR) was tested for its enhanced wound-healing efficacy. Results: While CuO-NPs did not inhibit P. aeruginosa growth at sub-inhibitory concentrations, they significantly reduced quorum sensing-associated virulence factors in a dose-dependent manner: LasB elastase (81.8%, 60.6%, and 53.03%), LasA protease (70%, 68.5%, and 57.1%), and pyocyanin (85.7%, 71.4%, and 55.9%). CuO-NPs exhibited strong antioxidant activity by scavenging free radicals. The combination of CuO-NPs and CUR demonstrated the highest wound-healing efficacy, outperforming the negative control and Mebo ointment by 193.9% and 61.6%, respectively. Additionally, CuO-NPs exhibited selective cytotoxicity against HepG2 cancer cells while displaying minimal toxicity toward normal human skin cells. Conclusions: CuO-NPs, particularly in combination with CUR, show promising potential as a therapeutic agent for wound healing by inhibiting quorum sensing-associated virulence factors, exhibiting strong antioxidant activity, and demonstrating selective cytotoxicity. These findings highlight their potential biomedical applications. Full article
(This article belongs to the Section Pharmacology)
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28 pages, 9029 KiB  
Article
Petrogenesis, Geochemistry, and Geological Significance of the Kongco Granitic Porphyry Dykes in the Northern Part of the Central Lhasa Microblock, Tibet
by Anping Xiang, Hong Liu, Wenxin Fan, Qing Zhou, Hong Wang and Kaizhi Li
Minerals 2025, 15(3), 283; https://doi.org/10.3390/min15030283 - 11 Mar 2025
Viewed by 780
Abstract
The Kongco area of Nima in the northern part of the Lhasa terrane has a suite of alkaline granitic porphyry dykes associated with Early Cretaceous granites and accompanied by Cu/Mo mineralization. LA-ICP-MS 206Pb/238U zircon geochronology performed on the dykes produced [...] Read more.
The Kongco area of Nima in the northern part of the Lhasa terrane has a suite of alkaline granitic porphyry dykes associated with Early Cretaceous granites and accompanied by Cu/Mo mineralization. LA-ICP-MS 206Pb/238U zircon geochronology performed on the dykes produced an age of 104.15 ± 0.94 Ma (MSWD = 0.98), indicating the Early Cretaceous emplacement of the dykes. The dykes exhibit high silica (SiO2 = 76.22~77.90 wt.%), high potassium (K2O = 4.97~6.21 wt.%), high alkalinity (K2O + Na2O = 8.07~8.98 wt.%), low calcium (CaO = 0.24~0.83 wt.%), low magnesium (MgO = 0.06~0.20 wt.%), and moderate aluminum content (Al2O3 = 11.93~12.45 wt.%). The Rieterman index (σ) ranges from 1.93 to 2.34. A/NK (molar ratio Al2O3/(Na2O + K2O)) and A/CNK (molar ratio Al2O3/(CaO + Na2O + K2O)) values of the dykes range from 1.06 to 1.18 and 0.98 to 1.09, respectively. The dykes are relatively enriched in Rb, Th, U, K, Ta, Ce, Nd, Zr, Hf, Sm, Y, Yb, and Lu, and they show a noticeable relative depletion in Ba, Nb, Sr, P, Eu, and Ti, as well as an average differentiation index (DI) of 96.42. The dykes also exhibit high FeOT/MgO ratios (3.60~10.41), Ga/Al ratios (2.22 × 10−4~3.01 × 10−4), Y/Nb ratios (1.75~2.40), and Rb/Nb ratios (8.36~20.76). Additionally, they have high whole-rock Zr saturation temperatures (884~914 °C), a pronounced Eu negative anomaly (δEu = 0.04~0.23), and a rightward-sloping “V-shaped” rare earth element pattern. These characteristics suggest that the granitic porphyry dykes can be classified as A2-type granites formed in a post-collisional tectonic environment and that they are weakly peraluminous, high-potassium, and Calc-alkaline basaltic rocks. Positive εHf(t) values = 0.43~3.63 and a relatively young Hf crustal model age (TDM2 = 826~1005 Ma, 87Sr/86Sr ratios = 0.7043~0.7064, and εNd(t) = −8.60~−2.95 all indicate lower crust and mantle mixing. The lower crust and mantle mixing model is also supported by (206Pb/204Pb)t = 18.627~18.788, (207Pb/204Pb)t = 15.707~15.719, (208Pb/204Pb)t = 39.038~39.110). Together, the Hf, Sr and Pb isotopic ratios indicate that the Kongco granitic porphyry dykes where derived from juvenile crust formed by the addition of mantle material to the lower crust. From this, we infer that the Kongco granitic porphyry dykes are related to a partial melting of the lower crust induced by subduction slab break-off and asthenospheric upwelling during the collision between the Qiangtang and Lhasa terranes and that they experienced significant fractional crystallization dominated by potassium feldspar and amphibole. These dykes are also accompanied by significant copper mineralization (five samples, copper content 0.2%), suggesting a close relationship between the magmatism associated with these dykes and regional metallogenesis, indicating a high potential for mineral exploration. Full article
(This article belongs to the Special Issue Using Mineral Chemistry to Characterize Ore-Forming Processes)
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21 pages, 8306 KiB  
Article
Magmatic–Hydrothermal Processes of the Pulang Giant Porphyry Cu (–Mo–Au) Deposit, Western Yunnan: A Perspective from Different Generations of Titanite
by Mengmeng Li, Xue Gao, Guohui Gu and Sheng Guan
Minerals 2025, 15(3), 263; https://doi.org/10.3390/min15030263 - 3 Mar 2025
Viewed by 767
Abstract
The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry [...] Read more.
The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry (skarn) type Cu–Mo ± Au polymetallic deposits, the largest of which is the Pulang Cu (–Mo–Au) deposit with proven Cu reserves of 5.11 Mt, Au reserves of 113 t, and 0.17 Mt of molybdenum. However, the relationship between mineralization and the potassic alteration zone, phyllic zone, and propylitic zone of the Pulang porphyry deposit is still controversial and needs further study. Titanite (CaTiSiO5) is a common accessory mineral in acidic, intermediate, and alkaline igneous rocks. It is widely developed in various types of metamorphic rocks, hydrothermally altered rocks, and a few sedimentary rocks. It is a dominant Mo-bearing phase in igneous rocks and contains abundant rare earth elements and high-field-strength elements. As an effective geochronometer, thermobarometer, oxybarometer, and metallogenic potential indicator mineral, titanite is ideal to reveal the magmatic–hydrothermal evolution and the mechanism of metal enrichment and precipitation. In this paper, major and trace element contents of the titanite grains from different alteration zones were obtained using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to define the changes in physicochemical conditions and the behavior of these elements during the process of hydrothermal alteration at Pulang. Titanite in the potassic alteration zone is usually shaped like an envelope. It occurs discretely or is enclosed by feldspar, with lower contents of CaO, Al, Sr, Zr and Hf; a low Nb/Ta ratio; high ∑REE + Y, U, Th, Ta, Nb, and Ga content; and high FeO/Al2O3 and LREE/HREE ratios. This is consistent with the characteristics of magmatic titanite from fresh quartz monzonite porphyry in Pulang and other porphyry Cu deposits. Titanite in the potassium silicate alteration zone has more negative Eu anomaly and a higher U content and Th/U ratio, indicating that the oxygen fugacity decreased during the transformation to phyllic alteration and propylitic alteration in Pulang. High oxygen fugacity is favorable for the enrichment of copper, gold, and other metallogenic elements. Therefore, the enrichment of copper is more closely related to the potassium silicate alteration. The molybdenum content of titanite in the potassium silicate alteration zone is 102–104 times that of the phyllic alteration zone and propylitic alteration zone, while the copper content is indistinctive, indicating that molybdenum was dissolved into the fluid or deposited in the form of sulfide before the medium- to low-temperature hydrothermal alteration, which may lead to the further separation and deposition of copper and molybdenum. Full article
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14 pages, 10847 KiB  
Article
Promoting Effect of Copper Doping on LaMO3 (M = Mn, Fe, Co, Ni) Perovskite-Supported Gold Catalysts for Selective Gas-Phase Ethanol Oxidation
by Lijun Yue, Jie Wang and Peng Liu
Catalysts 2025, 15(2), 176; https://doi.org/10.3390/catal15020176 - 13 Feb 2025
Cited by 1 | Viewed by 958
Abstract
Developing more effective gold–support synergy is essential for enhancing the catalytic performance of supported gold nanoparticles (AuNPs) in the gas-phase oxidation of ethanol to acetaldehyde (AC) at lower temperatures. This study demonstrates a significantly improved Au–support synergy achieved by copper doping in LaMO [...] Read more.
Developing more effective gold–support synergy is essential for enhancing the catalytic performance of supported gold nanoparticles (AuNPs) in the gas-phase oxidation of ethanol to acetaldehyde (AC) at lower temperatures. This study demonstrates a significantly improved Au–support synergy achieved by copper doping in LaMO3 (M = Mn, Fe, Co, Ni) perovskites. Among the various Au/LaMCuO3 catalysts, Au/LaMnCuO3 exhibited exceptional catalytic activity, achieving an AC yield of up to 91% and the highest space-time yield of 764 gAC gAu−1 h−1 at 225 °C. Notably, this catalyst showed excellent hydrothermal stability, maintaining performance for at least 100 h without significant deactivation when fed with 50% aqueous ethanol. Comprehensive characterization reveals that Cu doping facilitates the formation of surface oxygen vacancies on the Au/LaMCuO3 catalysts and enhances Au–support interactions. The LaMnCuO3 perovskite stabilizes the crucial Cu+ species, resulting in a stable Au-Mn-Cu synergy within the Au/LaMnCuO3 catalyst, which facilitates the activation of O2 and ethanol at lower temperatures. The optimization of the reaction conditions further improves AC productivity. Kinetic studies indicate that the cleavages of both the O-H bond and the α-C-H bond of ethanol are the rate-controlling steps. Full article
(This article belongs to the Special Issue New Insights into Synergistic Dual Catalysis)
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