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17 pages, 972 KiB  
Article
A Preliminary Investigation into Heavy Metal Tolerance in Pseudomonas Isolates: Does the Isolation Site Have an Effect?
by Alessandro De Santis, Antonio Bevilacqua, Angela Racioppo, Barbara Speranza, Maria Rosaria Corbo, Clelia Altieri and Milena Sinigaglia
Agriculture 2025, 15(15), 1692; https://doi.org/10.3390/agriculture15151692 - 5 Aug 2025
Abstract
One hundred presumptive Pseudomonas isolates, recovered from 15 sites impacted by anthropogenic activity in the Foggia district (Italy), were screened for key adaptive and functional traits important for environmental applications. The isolates were phenotypically characterized for their ability to grow under combined pH [...] Read more.
One hundred presumptive Pseudomonas isolates, recovered from 15 sites impacted by anthropogenic activity in the Foggia district (Italy), were screened for key adaptive and functional traits important for environmental applications. The isolates were phenotypically characterized for their ability to grow under combined pH (5.0–8.0) and temperature (15–37 °C) conditions, to produce proteolytic enzymes, pigments, and exopolysaccharides, and to tolerate SDS. Moreover, the resistance to six environmentally relevant heavy metals (Cd, Co, Cu, Ni, Zn, As) was qualitatively assessed. The results highlighted wide inter-strain variability, with distinct clusters of isolates showing unique combinations of stress tolerance, enzymatic potential, and resistance profile. PERMANOVA analysis revealed significant effects of both the isolation site and the metal type, as well as their interaction, on the observed resistance patterns. A subset of isolates showed co-tolerance to elevated temperatures and heavy metals. These findings offer an initial yet insightful overview of the adaptive diversity of soil-derived Pseudomonas, laying the groundwork for the rational selection of strains for bioaugmentation in contaminated soils. Full article
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14 pages, 1527 KiB  
Article
The Effect of the Metal Impurities on the Stability, Chemical, and Sensing Properties of MoSe2 Surfaces
by Danil W. Boukhvalov, Murat K. Rakhimzhanov, Aigul Shongalova, Abay S. Serikkanov, Nikolay A. Chuchvaga and Vladimir Yu. Osipov
Surfaces 2025, 8(3), 56; https://doi.org/10.3390/surfaces8030056 - 5 Aug 2025
Abstract
In this study, we present a comprehensive theoretical analysis of modifications in the physical and chemical properties of MoSe2 upon the introduction of substitutional transition metal impurities, specifically, Ti, V, Cr, Fe, Co, Ni, Cu, W, Pd, and Pt. Wet systematically calculated [...] Read more.
In this study, we present a comprehensive theoretical analysis of modifications in the physical and chemical properties of MoSe2 upon the introduction of substitutional transition metal impurities, specifically, Ti, V, Cr, Fe, Co, Ni, Cu, W, Pd, and Pt. Wet systematically calculated the adsorption enthalpies for various representative analytes, including O2, H2, CO, CO2, H2O, NO2, formaldehyde, and ethanol, and further evaluated their free energies across a range of temperatures. By employing the formula for probabilities, we accounted for the competition among molecules for active adsorption sites during simultaneous adsorption events. Our findings underscore the importance of integrating temperature effects and competitive adsorption dynamics to predict the performance of highly selective sensors accurately. Additionally, we investigated the influence of temperature and analyte concentration on sensor performance by analyzing the saturation of active sites for specific scenarios using Langmuir sorption theory. Building on our calculated adsorption energies, we screened the catalytic potential of doped MoSe2 for CO2-to-methanol conversion reactions. This paper also examines the correlations between the electronic structure of active sites and their associated sensing and catalytic capabilities, offering insights that can inform the design of advanced materials for sensors and catalytic applications. Full article
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21 pages, 1245 KiB  
Article
Geochemical Behaviour of Trace Elements in Diesel Oil-Contaminated Soil During Remediation Assisted by Mineral and Organic Sorbents
by Mirosław Wyszkowski and Natalia Kordala
Appl. Sci. 2025, 15(15), 8650; https://doi.org/10.3390/app15158650 (registering DOI) - 5 Aug 2025
Abstract
The topic of environmental pollution by petroleum products is highly relevant due to rapid urbanisation, including industrial development, road infrastructure and fuel distribution. Potential threat areas include refineries, fuel stations, pipelines, warehouses and transshipment bases, as well as sites affected by accidents or [...] Read more.
The topic of environmental pollution by petroleum products is highly relevant due to rapid urbanisation, including industrial development, road infrastructure and fuel distribution. Potential threat areas include refineries, fuel stations, pipelines, warehouses and transshipment bases, as well as sites affected by accidents or fuel spills. This study aimed to determine whether organic and mineral materials could mitigate the effects of diesel oil pollution on the soil’s trace element content. The used materials were compost, bentonite and calcium oxide. Diesel oil pollution had the most pronounced effect on the levels of Cd, Ni, Fe and Co. The levels of the first three elements increased, while the level of Co decreased by 53%. Lower doses of diesel oil (2.5 and 5 cm3 per kg of soil) induced an increase in the levels of the other trace elements, while higher doses caused a reduction, especially in Cr. All materials applied to the soil (compost, bentonite and calcium oxide) reduced the content of Ni, Cr and Fe. Compost and calcium oxide also increased Co accumulation in the soil. Bentonite had the strongest reducing effect on the Ni and Cr contents of the soil, reducing them by 42% and 53%, respectively. Meanwhile, calcium oxide had the strongest reducing effect on Fe and Co accumulation, reducing it by 12% and 31%, respectively. Inverse relationships were recorded for Cd (mainly bentonite), Pb (especially compost), Cu (mainly compost), Mn (mainly bentonite) and Zn (only compost) content in the soil. At the most contaminated site, the application of bentonite reduced the accumulation of Pb, Zn and Mn in the soil, while the application of compost reduced the accumulation of Cd. Applying various materials, particularly bentonite and compost, limits the content of certain trace elements in the soil. This has a positive impact on reducing the effect of minor diesel oil pollution on soil properties and can promote the proper growth of plant biomass. Full article
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15 pages, 1752 KiB  
Article
Acetate-Assisted Preparation of High-Cu-Content Cu-SSZ-13 with a Low Si/Al Ratio: Distinguishing Cu Species and Origins
by Dongxu Han, Ying Xin, Junxiu Jia, Jin Wang and Zhaoliang Zhang
Catalysts 2025, 15(8), 741; https://doi.org/10.3390/catal15080741 - 4 Aug 2025
Abstract
The rational design of high-performance Cu-SSZ-13 catalysts with enhanced low-temperature activity represents a critical challenge for meeting stringent Euro VII emission standards in diesel aftertreatment systems. Elevating Cu loading can theoretically improve catalytic performance; however, one-time ion exchange using common CuSO4 solution [...] Read more.
The rational design of high-performance Cu-SSZ-13 catalysts with enhanced low-temperature activity represents a critical challenge for meeting stringent Euro VII emission standards in diesel aftertreatment systems. Elevating Cu loading can theoretically improve catalytic performance; however, one-time ion exchange using common CuSO4 solution makes it hard to accomplish high Cu-ion contents. Herein, we demonstrate that the conventional ion-exchange method, adopting Cu(CH3COO)2 as precursor in NH4-SSZ-13 zeolite with a low Si/Al ratio (≈6–7), can achieve higher Cu content while maintaining superior dispersion of active sites. Comprehensive characterizations reveal a dual incorporation mechanism: canonical Cu2+ ion exchange and unique adsorption of the [Cu(CH3COO)]+ complex. In the latter case, the surface-adsorbed [Cu(CH3COO)]+ ions form high-dispersion CuOx species, while the framework-confined ones convert to active Z[Cu2+(OH)]+ ions. The Cu(CH3COO)2-exchanged Cu-SSZ-13 catalyst exhibits superior low-temperature SCR activity and hydrothermal stability to its CuSO4-exchanged counterpart, making it particularly suitable for close-coupled SCR applications. Our findings provide fundamental insights into Cu speciation control in zeolites and present a scalable, industrially viable approach for manufacturing next-generation SCR catalysts capable of meeting future emission regulations. Full article
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15 pages, 5007 KiB  
Article
In Situ Construction of Thiazole-Linked Covalent Organic Frameworks on Cu2O for High-Efficiency Photocatalytic Tetracycline Degradation
by Zhifang Jia, Tingxia Wang, Zhaoxia Wu, Shumaila Razzaque, Zhixiang Zhao, Jiaxuan Cai, Wenao Xie, Junli Wang, Qiang Zhao and Kewei Wang
Molecules 2025, 30(15), 3233; https://doi.org/10.3390/molecules30153233 - 1 Aug 2025
Viewed by 155
Abstract
The strategic construction of heterojunctions through a simple and efficient strategy is one of the most effective means to boost the photocatalytic activity of semiconductor materials. Herein, a thiazole-linked covalent organic framework (TZ-COF) with large surface area, well-ordered pore structure, and high stability [...] Read more.
The strategic construction of heterojunctions through a simple and efficient strategy is one of the most effective means to boost the photocatalytic activity of semiconductor materials. Herein, a thiazole-linked covalent organic framework (TZ-COF) with large surface area, well-ordered pore structure, and high stability was developed. To further boost photocatalytic activity, the TZ-COF was synthesized in situ on the surface of Cu2O through a simple multicomponent reaction, yielding an encapsulated composite material (Cu2O@TZ-COF-18). In this composite, the outermost COF endows the material with abundant redox active sites and mass transfer channels, while the innermost Cu2O exhibits unique photoelectric properties. Notably, the synthesized Cu2O@TZ-COF-18 was proven to have the heterojunction structure, which can efficiently restrain the recombination of photogenerated electron–hole pairs, thereby enhancing the photocatalytic performance. The photocatalytic degradation of tetracycline demonstrated that 3-Cu2O@TZ-COF-18 had the highest photocatalytic efficiency, with the removal rate of 96.3% within 70 min under visible light, which is better than that of pristine TZ-COF-18, Cu2O, the physical mixture of Cu2O and TZ-COF-18, and numerous reported COF-based composite materials. 3-Cu2O@TZ-COF-18 retained its original crystallinity and removal efficiency after five cycles in photodegradation reaction, displaying high stability and excellent cycle performance. Full article
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22 pages, 1289 KiB  
Article
Assessment of Heavy Metal Contamination and Human Health Risk in Parapenaeus longirostris from Coastal Tunisian Aquatic Ecosystems
by Walid Ben Ameur, Ali Annabi, Kaddachi Rania and Mauro Marini
Pollutants 2025, 5(3), 23; https://doi.org/10.3390/pollutants5030023 - 1 Aug 2025
Viewed by 215
Abstract
Seafood contamination by heavy metals is a growing public health concern, particularly in regions like Tunisia where seafood is a major dietary component. This study assessed concentrations of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in the muscle tissue of the [...] Read more.
Seafood contamination by heavy metals is a growing public health concern, particularly in regions like Tunisia where seafood is a major dietary component. This study assessed concentrations of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in the muscle tissue of the red shrimp Parapenaeus longirostris, collected in 2023 from four coastal regions: Bizerte, Monastir, Kerkennah, and Gabes. Metal analysis was conducted using flame atomic absorption spectroscopy. This species was chosen due to its ecological and economic importance. The study sites were chosen based on their differing levels of industrial, urban, and agricultural influence, providing a representative overview of regional contamination patterns. Mean concentrations were 1.04 µg/g for Zn, 0.59 µg/g for Cu, 1.56 µg/g for Pb, and 0.21 µg/g for Cd (dry weight). Pb was the most prevalent metal across sites. Statistically significant variation was observed only for Cu (p = 0.0334). All metal concentrations were below international safety limits set by FAO/WHO and the European Union. Compared to similar studies, the levels reported were similar or slightly lower. Human health risk was evaluated using target hazard quotient (THQ), hazard index (HI), and cancer risk (CR) values. For adults, THQ ranged from 5.44 × 10−6 to 8.43 × 10−4, while for children it ranged from 2.40 × 10−5 to 3.72 × 10−3. HI values were also well below 1, indicating negligible non-carcinogenic risk. CR values for Cd and Pb in both adults and children fell within the acceptable risk range (10−6 to <10−4), suggesting no significant carcinogenic concern. This study provides the first field-based dataset on metal contamination in P. longirostris from Tunisia, contributing valuable insights for seafood safety monitoring and public health protection. Full article
(This article belongs to the Special Issue Marine Pollutants: 3rd Edition)
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13 pages, 1866 KiB  
Article
Application of Humate-Containing Agent for Sorbing Trace Metals in Simulated Solutions and Surface Waters from Tunnels at the ‘Degelen’ Site
by Madina Dyussembayeva, Yerbol Shakenov, Vladimir Kolbin, Azhar Tashekova, Assan Aidarkhanov, Umirzak Dzhusipbekov, Gulzipa Nurgalieva, Zamira Bayakhmetova, Dulat Duisenbay and Ulzhan Aksakalova
Sustainability 2025, 17(15), 6921; https://doi.org/10.3390/su17156921 - 30 Jul 2025
Viewed by 169
Abstract
This article presents the potential use of a humic agent called ‘Superhumate’, obtained from weathered coal from the Shubarkol deposit in Kazakhstan. The experiment was conducted using model solutions and surface mine water samples from the “Degelen” site at the Semipalatinsk Test Site. [...] Read more.
This article presents the potential use of a humic agent called ‘Superhumate’, obtained from weathered coal from the Shubarkol deposit in Kazakhstan. The experiment was conducted using model solutions and surface mine water samples from the “Degelen” site at the Semipalatinsk Test Site. The adsorption of heavy metals and toxic elements using the “Superhumate” agent was carried out under dynamic conditions using a chromatographic column. Tests were conducted at a natural pH range of 5–8 (mine waters) and with a model solution at pH 1.7. Assessing the sorption efficiency of this preparation revealed that at pH 1.7, the agent does not adsorb elements such as Cd, Cu, Pb, and Zn. Under dynamic experimental conditions, using the preparation for mine waters at natural pH levels (pH 5–8), elements such as Be, Sr, Mo, Cd, Cs, Zn, and U were efficiently adsorbed at levels of 60–95%. The sorption efficiency of Pb ions was found to be almost independent of pH. The experimental results obtained with mine water samples indicate that alkaline solutions have the highest sorption efficiency, with pH ≥ 7, which is attributed to the solubility of the agent. Full article
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13 pages, 5877 KiB  
Article
Effect of Interval Time Between Pre-Deformation and Artificial Aging on Mechanical Properties of Er-Containing 7075 Aluminum Alloy
by Yingze Liu, Zhiqian Liao, Desheng Wang, Guoyuan Liu, Jiangyi Ren, Wenfu Li, Yunao Yang, Lingjie Chen and Yue Wang
Metals 2025, 15(8), 841; https://doi.org/10.3390/met15080841 - 28 Jul 2025
Viewed by 181
Abstract
In order to obtain the optimal heat treatment process of Er-containing 7075 aluminum alloy, the effects of pre-stretching and the interval time between pre-stretching and aging on the microstructure and mechanical properties of Er-containing 7075 aluminum alloy during solution treatment followed by pre-stretching [...] Read more.
In order to obtain the optimal heat treatment process of Er-containing 7075 aluminum alloy, the effects of pre-stretching and the interval time between pre-stretching and aging on the microstructure and mechanical properties of Er-containing 7075 aluminum alloy during solution treatment followed by pre-stretching and two-stage aging processes were investigated by mechanical property tests, metallographic tests, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the mechanical properties of Er-containing 7075 aluminum alloy can be significantly improved by increasing the extrusion ratio. Pre-stretching provides nucleation sites for the precipitation of reinforcing phases, accelerates the aging strengthening process, and shortens the peak aging time. The crack source of fracture in Er-containing 7075 aluminum alloy is attributed to the segregated second phases containing Cu and Er in the alloy. The research results have significant engineering significance for the optimization of the heat treatment process of Er-containing 7075 aluminum alloy. Full article
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18 pages, 1555 KiB  
Review
Immobilization of Cadmium, Lead, and Copper in Soil Using Bacteria: A Literature Review
by Saulius Vasarevičius and Vaida Paliulienė
Land 2025, 14(8), 1547; https://doi.org/10.3390/land14081547 - 28 Jul 2025
Viewed by 303
Abstract
The heavy metal contamination of soils is a global environmental challenge threatening water quality, food safety, and human health. Using a systematic literature review approach, this study aimed to assess the potential of bacterial strains to immobilize cadmium (Cd2+), lead (Pb [...] Read more.
The heavy metal contamination of soils is a global environmental challenge threatening water quality, food safety, and human health. Using a systematic literature review approach, this study aimed to assess the potential of bacterial strains to immobilize cadmium (Cd2+), lead (Pb2+), and copper (Cu2+) in contaminated soils. A total of 45 articles were analyzed, focusing on studies that reported heavy metal concentrations before and after bacterial treatment. The analysis revealed that bacterial genera such as Bacillus, Pseudomonas, and Enterobacter were most commonly used for the immobilization of these metals. Immobilization efficiencies ranged from 25% to over 98%, with higher efficiencies generally observed when microbial consortia or amendments (e.g., phosphate compounds and biochar) were applied. The main immobilization mechanisms included biosorption, bioprecipitation (such as carbonate-induced precipitation), bioaccumulation, and biomineralization, which convert mobile metal ions into more stable, less bioavailable forms. These findings highlight the promising role of microbial-assisted immobilization in mitigating heavy metal pollution and reducing ecological risks. Further laboratory and field studies are needed to optimize the use of these microbial strains under site-specific conditions to ensure effective and sustainable soil remediation practices. Full article
(This article belongs to the Section Land Use, Impact Assessment and Sustainability)
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22 pages, 6926 KiB  
Article
Exploring Heavy Metals Exposure in Urban Green Zones of Thessaloniki (Northern Greece): Risks to Soil and People’s Health
by Ioannis Papadopoulos, Evangelia E. Golia, Ourania-Despoina Kantzou, Sotiria G. Papadimou and Anna Bourliva
Toxics 2025, 13(8), 632; https://doi.org/10.3390/toxics13080632 - 27 Jul 2025
Viewed by 928
Abstract
This study investigates the heavy metal contamination in urban and peri-urban soils of Thessaloniki, Greece, over a two-year period (2023–2024). A total of 208 composite soil samples were systematically collected from 52 sites representing diverse land uses, including high-traffic roadsides, industrial zones, residential [...] Read more.
This study investigates the heavy metal contamination in urban and peri-urban soils of Thessaloniki, Greece, over a two-year period (2023–2024). A total of 208 composite soil samples were systematically collected from 52 sites representing diverse land uses, including high-traffic roadsides, industrial zones, residential neighborhoods, parks, and mixed-use areas, with sampling conducted both after the wet (winter) and dry (summer) seasons. Soil physicochemical properties (pH, electrical conductivity, texture, organic matter, and calcium carbonate content) were analyzed alongside the concentrations of heavy metals such as Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn. A pollution assessment employed the Geoaccumulation Index (Igeo), Contamination Factor (Cf), Pollution Load Index (PLI), and Potential Ecological Risk Index (RI), revealing variable contamination levels across the city, with certain hotspots exhibiting a considerable to very high ecological risk. Multivariate statistical analyses (PCA and HCA) identified distinct anthropogenic and geogenic sources of heavy metals. Health risk assessments, based on USEPA models, evaluated non-carcinogenic and carcinogenic risks for both adults and children via ingestion and dermal contact pathways. The results indicate that while most sites present low to moderate health risks, specific locations, particularly near major transport and industrial areas, pose elevated risks, especially for children. The findings underscore the need for targeted monitoring and remediation strategies to mitigate the ecological and human health risks associated with urban soil pollution in Thessaloniki. Full article
(This article belongs to the Special Issue Distribution and Behavior of Trace Metals in the Environment)
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14 pages, 728 KiB  
Article
Groundwater Quality Analysis: Assessing the Impact of a Closed Landfill—A Case Study on Physico-Chemical and Microplastic Contaminants
by Grzegorz Przydatek, Józef Ciuła, Narcis Barsan, Diana Mirila and Emilian Mosnegutu
Appl. Sci. 2025, 15(15), 8223; https://doi.org/10.3390/app15158223 - 24 Jul 2025
Viewed by 306
Abstract
In the context of increasing concern over long-term environmental impacts of closed landfill sites, this study investigates the composition of groundwater and leachate at a municipal waste landfill in southwestern Poland, two decades after its closure. The research, conducted in 2023, aimed to [...] Read more.
In the context of increasing concern over long-term environmental impacts of closed landfill sites, this study investigates the composition of groundwater and leachate at a municipal waste landfill in southwestern Poland, two decades after its closure. The research, conducted in 2023, aimed to assess groundwater quality using 11 physico-chemical and 13 microplastic indicators. Groundwater and leachate samples were collected seasonally to assess of groundwater quality around landfill, including presence of heavy metals (Cd, Cr6+, Cu, Pb), PAHs and TOC, and microplastics. The results revealed persistent environmental degradation, with elevated concentrations of total organic carbon (24.8 mg/L) and cadmium (0.0211 mg/L), particularly in the second half of the year. Additionally, PET microplastics were detected in correlation with increased precipitation and leachate generation. These findings indicate that pollutants continue to migrate from the waste deposit into the surrounding groundwater, with seasonal patterns amplifying their presence. The study confirms that even decades after closure, municipal landfills can remain significant sources of both chemical and microplastic contamination, underlining the need for long-term monitoring and remediation strategies to protect groundwater resources. Full article
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18 pages, 1829 KiB  
Article
The Red Shift in Estrogen Research: An Estrogen-Receptor Targeted aza-BODIPY–Estradiol Fluorescent Conjugate
by Tamás Hlogyik, Noémi Bózsity, Rita Börzsei, Benjámin Kovács, Péter Labos, Csaba Hetényi, Mónika Kiricsi, Ildikó Huliák, Zoltán Kele, Miklós Poór, János Erostyák, Attila Hunyadi, István Zupkó and Erzsébet Mernyák
Int. J. Mol. Sci. 2025, 26(15), 7075; https://doi.org/10.3390/ijms26157075 - 23 Jul 2025
Viewed by 216
Abstract
Estradiol (E2) plays an important role in cell proliferation and certain brain functions. To reveal its mechanism of action, its detectability is essential. Only a few fluorescent-labeled hormonally active E2s exist in the literature, and their mechanism of action usually remains unclear. It [...] Read more.
Estradiol (E2) plays an important role in cell proliferation and certain brain functions. To reveal its mechanism of action, its detectability is essential. Only a few fluorescent-labeled hormonally active E2s exist in the literature, and their mechanism of action usually remains unclear. It would be of particular interest to develop novel labeled estradiol derivatives with retained biological activity and improved optical properties. Due to their superior optical characteristics, aza-BODIPY dyes are frequently used labeling agents in biomedical applications. E2 was labeled with the aza-BODIPY dye at its phenolic hydroxy function via an alkyl linker and a triazole coupling moiety. The estrogenic activity of the newly synthesized fluorescent conjugate was evaluated via transcriptional luciferase assay. Docking calculations were performed for the classical and alternative binding sites (CBS and ABS) of human estrogen receptor α. The terminal alkyne function was introduced into the tetraphenyl aza-BODIPY core via selective formylation, oxidation, and subsequent amidation with propargyl amine. The conjugation was achieved via Cu(I)-catalyzed azide–alkyne click reaction of the aza-BODIPY-alkyne with the 3-O-(4-azidobut-1-yl) derivative of E2. The labeled estrogen induced a dose-dependent transcriptional activity of human estrogen receptor α with a submicromolar EC50 value. Docking calculations revealed that the steroid part has a perfect overlap with E2 in ABS. In CBS, however, a head-tail binding deviation was observed. A facile, fluorescent labeling methodology has been elaborated for the development of a novel red-emitting E2 conjugate with substantial estrogenic activity. Docking experiments uncovered the binding mode of the conjugate in both ABS and CBS. Full article
(This article belongs to the Section Biochemistry)
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15 pages, 2059 KiB  
Article
Strain Engineering of Cu2O@C2N for Enhanced Methane-to-Methanol Conversion
by Shuxin Kuai, Bo Li and Jingyao Liu
Molecules 2025, 30(15), 3073; https://doi.org/10.3390/molecules30153073 - 23 Jul 2025
Viewed by 235
Abstract
Inspired by the active site of methane monooxygenase, we designed a Cu2O cluster anchored in the six-membered nitrogen cavity of a C2N monolayer (Cu2O@C2N) as a stable and efficient enzyme-like catalyst. Density functional theory (DFT) [...] Read more.
Inspired by the active site of methane monooxygenase, we designed a Cu2O cluster anchored in the six-membered nitrogen cavity of a C2N monolayer (Cu2O@C2N) as a stable and efficient enzyme-like catalyst. Density functional theory (DFT) calculations reveal that the bridged Cu-O-Cu structure within C2N exhibits strong electronic coupling, which is favorable for methanol formation. Two competing mechanisms—the concerted and radical-rebound pathways—were systematically investigated, with the former being energetically preferred due to lower energy barriers and more stable intermediate states. Furthermore, strain engineering was employed to tune the geometric and electronic structure of the Cu-O-Cu site. Biaxial strain modulates the Cu-O-Cu bond angle, adsorption properties, and d-band center alignment, thereby selectively enhancing the concerted pathway. A volcano-like trend was observed between the applied strain and the methanol formation barrier, with 1% tensile strain yielding the overall energy barrier to methanol formation (ΔGoverall) as low as 1.31 eV. N2O effectively regenerated the active site and demonstrated strain-responsive kinetics. The electronic descriptor Δε (εd − εp) captured the structure–activity relationship, confirming the role of strain in regulating catalytic performance. This work highlights the synergy between geometric confinement and mechanical modulation, offering a rational design strategy for advanced C1 activation catalysts. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Physical Chemistry, 3nd Edition)
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23 pages, 2483 KiB  
Article
A Unionid Mussel Biodiversity Hotspot Experiencing Unexplained Declines: Evaluating the Influence of Chemical Stressors Using Caged Juveniles
by W. Aaron Wilson, Christine Bergeron, Jennifer Archambault, Jason Unrine, Jess Jones, Braven Beaty, Damian Shea, Peter R. Lazaro, Jody L. Callihan, Jennifer J. Rogers and W. Gregory Cope
Diversity 2025, 17(8), 503; https://doi.org/10.3390/d17080503 - 22 Jul 2025
Viewed by 297
Abstract
Unionid mussel populations in a section of the Clinch River in Virginia, USA, has declined substantially, but the causes of the decline remain unknown. To investigate this zone of decline (ZOD), we deployed juvenile freshwater mussels (Villosa iris in 2012 and Lampsilis [...] Read more.
Unionid mussel populations in a section of the Clinch River in Virginia, USA, has declined substantially, but the causes of the decline remain unknown. To investigate this zone of decline (ZOD), we deployed juvenile freshwater mussels (Villosa iris in 2012 and Lampsilis fasciola in 2013) in both cages and silos at sites within the Clinch River System. We analyzed mussel tissues for trace element and organic contaminant concentrations, shells for trace elements, and environmental media (total water, dissolved water, particulate sediment, and bedload sediment) for both inorganic and organic contaminants. We found a few differences between mussels deployed in cages and those deployed in silos: survival was slightly lower in cages due to periodic sedimentation. Our results identified the ZOD based on the accumulation of trace elements (notably As, Cu, Fe, Mn, Ni, and Sr), polycyclic aromatic hydrocarbons (PAHs), and δ15N enrichment, with especially high concentrations found in the human-impacted tributaries, Dumps Creek and Guest River. Some correlations were found between environmental media and both mussel tissues and shells. In particular, PAHs and Mn had several significant relationships between bioaccumulated concentrations and environmental concentrations. Finally, Co, Cu, Fe, and V in soft tissues negatively correlated with mussel growth, whereas bioaccumulated PAH concentrations correlated negatively with resident mussel densities. Full article
(This article belongs to the Special Issue Freshwater Biodiversity Hotspots in 2025)
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28 pages, 3926 KiB  
Article
Could the Presence of Ferrihydrite in a Riverbed Impacted by Mining Leachates Be Linked to a Reduction in Contamination and Health Indexes?
by Asunción Guadalupe Morales-Mendoza, Ana Karen Ivanna Flores-Trujillo, Luz María Del-Razo, Betsy Anaid Peña-Ocaña, Fanis Missirlis and Refugio Rodríguez-Vázquez
Water 2025, 17(15), 2167; https://doi.org/10.3390/w17152167 - 22 Jul 2025
Viewed by 347
Abstract
Taxco de Alarcón (Mexico) has been affected by mining activities and the presence of potentially toxic elements (PTEs). In this study, water samples from the Acamixtla, Taxco, and San Juan rivers were analyzed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to determine [...] Read more.
Taxco de Alarcón (Mexico) has been affected by mining activities and the presence of potentially toxic elements (PTEs). In this study, water samples from the Acamixtla, Taxco, and San Juan rivers were analyzed using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to determine PTE concentrations. Statistical analyses included principal component analysis, Pearson’s correlation, the Pollution Index, and a Health Risk Assessment. Additionally, solid samples from the San Juan River with leachate from the “La Guadalupana” Mine (RSJMG S2.3) were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Identified PTEs included As, Cr, Ni, Zn, Fe, Mn, Cu, Cd, Pb, Se, and Li. Principal component analysis explained 94.8% of the data variance, and Pearson’s correlation revealed significant associations (p < 0.05) among Fe, As, Cu, Cd, Pb, and Zn. The RSJMG S2.3 site exhibited the highest Pollution Index value (8491.56) and the highest health exposure risks. Lower contamination levels at other sites may be attributed to the complexation of PTEs with ferrihydrite, which was identified in the RSJMG S2.3 site through microscopy and infrared analyses. These findings suggest that the in situ formation of ferrihydrite may enhance the adsorption of PTEs, thereby mitigating environmental contamination and potential health risks. Full article
(This article belongs to the Section Water Quality and Contamination)
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