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Keywords = acidic tailings

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14 pages, 1483 KiB  
Article
Molecular Dynamics Simulation of PFAS Adsorption on Graphene for Enhanced Water Purification
by Bashar Awawdeh, Matteo D’Alessio, Sasan Nouranian, Ahmed Al-Ostaz, Mine Ucak-Astarlioglu and Hunain Alkhateb
ChemEngineering 2025, 9(4), 83; https://doi.org/10.3390/chemengineering9040083 (registering DOI) - 1 Aug 2025
Viewed by 147
Abstract
The contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) presents a global concern due to their extreme persistence, driven by strong C–F bonds. This study investigated the potential of graphene as a filtration material for PFAS removal, focusing on six key [...] Read more.
The contamination of drinking water by per- and polyfluoroalkyl substances (PFASs) presents a global concern due to their extreme persistence, driven by strong C–F bonds. This study investigated the potential of graphene as a filtration material for PFAS removal, focusing on six key compounds regulated by the U.S. EPA: PFOA, PFNA, GenX, PFBS, PFOS, and PFHxS. Using molecular simulations, adsorption energy, diffusion coefficients, and PFAS-to-graphene distances were analyzed. The results showed that adsorption strength increased with molecular weight; PFOS (500 g/mol) exhibited the strongest adsorption (−171 kcal/mol). Compounds with sulfonic acid head groups (e.g., PFOS) had stronger interactions than those with carboxylate groups (e.g., PFNA), highlighting the importance of head group chemistry. Shorter graphene-to-PFAS distances also aligned with higher adsorption energies. PFOS, for example, had the shortest distance at 8.23 Å (head) and 6.15 Å (tail) from graphene. Diffusion coefficients decreased with increasing molecular weight and carbon chain length, with lower molecules like PFBS (four carbon atoms) diffusing more rapidly than heavier ones like PFOS and PFNA. Interestingly, graphene enhanced PFAS mobility in water, likely by disrupting the water structure and lowering intermolecular resistance. These results highlight graphene’s promise as a high-performance material for PFAS removal and future water purification technologies. Full article
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13 pages, 1750 KiB  
Article
Mineral-Based Synthesis of CuFe2O4 Nanoparticles via Co-Precipitation and Microwave Techniques Using Leached Copper Solutions from Mined Minerals
by Carolina Venegas Abarzúa, Mauricio J. Morel, Gabriela Sandoval-Hevia, Thangavel Kavinkumar, Natarajan Chidhambaram, Sathish Kumar Kamaraj, Nagarajan Dineshbabu and Arun Thirumurugan
Minerals 2025, 15(8), 819; https://doi.org/10.3390/min15080819 (registering DOI) - 1 Aug 2025
Viewed by 139
Abstract
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) [...] Read more.
Environmental sustainability and responsible resource utilization are critical global challenges. In this work, we present a sustainable and circular-economy-based approach for synthesizing CuFe2O4 nanoparticles by directly utilizing copper oxide minerals sourced from Chilean mining operations. Copper sulfate (CuSO4) was extracted from these minerals through acid leaching and used as a precursor for nanoparticle synthesis via both chemical co-precipitation and microwave-assisted methods. The influence of different precipitating agents—NaOH, Na2CO3, and NaF—was systematically evaluated. XRD and FESEM analyses revealed that NaOH produced the most phase-pure and well-dispersed nanoparticles, while NaF resulted in secondary phase formation. The microwave-assisted method further improved particle uniformity and reduced agglomeration due to rapid and homogeneous heating. Electrochemical characterization was conducted to assess the suitability of the synthesized CuFe2O4 for supercapacitor applications. Cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements confirmed pseudocapacitive behavior, with a specific capacitance of up to 1000 F/g at 2 A/g. These findings highlight the potential of CuFe2O4 as a low-cost, high-performance electrode material for energy storage. This study underscores the feasibility of converting primary mined minerals into functional nanomaterials while promoting sustainable mineral valorization. The approach can be extended to other critical metals and mineral residues, including tailings, supporting the broader goals of a circular economy and environmental remediation. Full article
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26 pages, 685 KiB  
Article
Novel Research Regarding Topical Use of Diclofenac in Dermatology—Non-Clinical and Clinical Data
by Diana Ana-Maria Nițescu, Horia Păunescu, Mihnea Costescu, Bogdan Nițescu, Laurențiu Coman, Ion Fulga and Oana Andreia Coman
Sci. Pharm. 2025, 93(3), 34; https://doi.org/10.3390/scipharm93030034 - 30 Jul 2025
Viewed by 230
Abstract
Diclofenac, an aryl-acetic acid derivative from the non-steroidal anti-inflammatory drug class, is the subject of multiple non-clinical and clinical studies regarding its usefulness in treating some dermatologic pathologies with an inflammatory, auto-immune, or proliferative component. Diclofenac is now approved for the topical treatment [...] Read more.
Diclofenac, an aryl-acetic acid derivative from the non-steroidal anti-inflammatory drug class, is the subject of multiple non-clinical and clinical studies regarding its usefulness in treating some dermatologic pathologies with an inflammatory, auto-immune, or proliferative component. Diclofenac is now approved for the topical treatment of actinic keratoses (AK), pre-malignant entities that have the risk of transformation into skin carcinomas. The hypothesis that diclofenac increases granular layer development in the mice tail model, having an anti-psoriatic effect, was demonstrated in a previous study in which 1% and 2% diclofenac ointment was evaluated. The aim of the present study was to perform experimental research on the topical effect of diclofenac in the mice tail model, by testing 4% and 8% diclofenac ointment, which is presented in the first part of the manuscript. In the second part of the manuscript, we also aimed to conduct a literature review regarding topical diclofenac uses in specific dermatological entities by evaluating the articles published in PubMed and Scopus databases during 2014–2025. The studies regarding the efficacy of topical diclofenac in dermatological diseases such as AK and field cancerization, actinic cheilitis, basal cell carcinoma, Bowen disease, Darier disease, seborrheic keratoses, and porokeratosis, were analyzed. The results of the experimental work showed a significant effect of 4% and 8% diclofenac ointment on orthokeratosis degree when compared to the negative control groups. Diclofenac in the concentration of 4% and 8% significantly increased the orthokeratosis degree compared to the negative control with untreated mice (p = 0.006 and p = 0.011, respectively, using the Kruskal–Wallis test) and to the negative control with vehicle (p = 0.006 and p = 0.011, respectively, using the Kruskal–Wallis test). The mean epidermal thickness was increased for the diclofenac groups, but not significantly when compared to the control groups. The results are concordant with our previous experiment, emphasizing the need for future clinical trials on the use of topical diclofenac in psoriasis. Full article
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11 pages, 2647 KiB  
Communication
The Interaction of pT73-Rab10 with Myosin Va, but Not Myosin Vb, Is Regulated Though a Site in the Globular Tail Domain
by Lynne A. Lapierre, Elizabeth H. Manning, Kyra S. Thomas, Catherine Caldwell and James R. Goldenring
Cells 2025, 14(15), 1140; https://doi.org/10.3390/cells14151140 - 24 Jul 2025
Viewed by 262
Abstract
The phosphorylation of Rab10 (pT73-Rab10) by LRRK2 promotes the establishment of epithelial cell polarity by controlling the trafficking to the primary cilia membrane of cilia-resident proteins and signaling proteins. Previous studies have identified a site in the globular tail domain of MYO5A that [...] Read more.
The phosphorylation of Rab10 (pT73-Rab10) by LRRK2 promotes the establishment of epithelial cell polarity by controlling the trafficking to the primary cilia membrane of cilia-resident proteins and signaling proteins. Previous studies have identified a site in the globular tail domain of MYO5A that specifically binds to only the phosphorylated form of Rab10. In this work, we have demonstrated that pT73-Rab10 does not associate with the globular tail of MYO5B. We have mapped the putative binding site to a required three amino acids (MEN, 1473–1475) in the MYO5A globular tail domain that are not found in the MYO5B globular tail. Substitution of the MEN amino acid sequence found in MYO5A into the paralogous position in the MYO5B globular tail conferred the ability to associate with pT73-Rab10. The results demonstrate that the interactors with MYO5A and MYO5B are not completely overlapping and that the interaction of pT73-Rab10 is specific to the MYO5A globular tail domain. Full article
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18 pages, 1052 KiB  
Article
Assessment of Tailings Contamination Potential in One of the Most Important Gold Mining Districts of Ecuador
by Daniel Garcés, Samantha Jiménez-Oyola, Yolanda Sánchez-Palencia, Fredy Guzmán-Martínez, Raúl Villavicencio-Espinoza, Sebastián Jaramillo-Zambrano, Victoria Rosado, Bryan Salgado-Almeida and Josué Marcillo-Guillén
Minerals 2025, 15(8), 767; https://doi.org/10.3390/min15080767 - 22 Jul 2025
Viewed by 374
Abstract
Mining waste presents significant environmental and public health risks due to the potential release of toxic substances when improperly managed. In this study, four tailings samples were taken to evaluate the environmental risks in the Ponce Enríquez mining area in Ecuador. Chemical characterization [...] Read more.
Mining waste presents significant environmental and public health risks due to the potential release of toxic substances when improperly managed. In this study, four tailings samples were taken to evaluate the environmental risks in the Ponce Enríquez mining area in Ecuador. Chemical characterization and X-ray Fluorescence Spectrometry (XRF) were used to analyze the content of potentially toxic elements (PTEs) of interest (As, Cd, Cr, Cu, Ni, Pb, and Zn), and X-ray Diffraction (XRD) for mineralogical characterization. The contamination index (IC) was calculated to assess the potential hazard associated with the content of PTEs in the mining wastes. To assess environmental risks, leaching tests were carried out to evaluate the potential release of PTEs, and Acid-Base Accounting (ABA) tests were conducted to determine the likelihood of acid mine drainage formation. The results revealed that the PETs concentration exceeded the maximum permissible limits in all samples, according to Ecuadorian regulations: As, Pb, and Cd were identified as critical contaminants. Mineralogically, quartz was the dominant phase, followed by carbonates (calcite, dolomite and magnesite), phyllosilicates (chlorite and illite), and minor amounts of pyrite and talc. The IC indicated high to very high contamination risk levels, with As being the predominant contributor. Although leaching tests met the established limits for non-hazardous mining waste, the ABA test showed that all samples had a high potential for long-term acid generation. These results underscore the need for implementing management strategies to mitigate the environmental impacts and the development of plans to protect local ecosystems and communities from the adverse effects of mining activities. Full article
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19 pages, 920 KiB  
Article
Natural Alternatives for Pain Relief: A Study on Morus alba, Angelica archangelica, Valeriana officinalis, and Passiflora incarnata
by Felicia Suciu, Oana Cristina Șeremet, Emil Ștefănescu, Ciprian Pușcașu, Cristina Isabel Viorica Ghiță, Cerasela Elena Gîrd, Robert Viorel Ancuceanu and Simona Negreș
J. Mind Med. Sci. 2025, 12(2), 39; https://doi.org/10.3390/jmms12020039 - 19 Jul 2025
Viewed by 275
Abstract
Background: Chronic pain poses a major global health burden, often inadequately managed by conventional analgesics due to limited efficacy and side effects. In this context, plant-based therapies offer a promising alternative. This study aimed to evaluate the antioxidant and analgesic potential of four [...] Read more.
Background: Chronic pain poses a major global health burden, often inadequately managed by conventional analgesics due to limited efficacy and side effects. In this context, plant-based therapies offer a promising alternative. This study aimed to evaluate the antioxidant and analgesic potential of four medicinal plants traditionally used for pain relief: Morus alba, Angelica archangelica, Valeriana officinalis, and Passiflora incarnata. Methods: Phytochemical analyses quantified total phenolic acid, flavonoid, and polyphenolic acid contents in the extracts. Antioxidant activity was assessed using the ABTS radical scavenging assay. Analgesic effects were evaluated in vivo using the hot-plate and tail-flick tests in mice treated for 14 days with plant extracts or paracetamol. Results: Morus alba showed the highest polyphenolic content and strongest antioxidant activity (IC50 = 0.0695 mg/mL). In analgesic tests, Angelica archangelica demonstrated the most significant effect in the hot-plate test (72.2% increase in latency), while Valeriana officinalis had the highest efficacy in the tail-flick test (41.81%), exceeding paracetamol’s performance in that model. Conclusions: While antioxidant activity correlated with polyphenol content, analgesic effects appeared to involve additional mechanisms. These findings support the potential of Angelica archangelica and Valeriana officinalis as effective natural alternatives for pain relief. Full article
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34 pages, 3875 KiB  
Article
Basis for a New Life Cycle Inventory for Metals from Mine Tailings Using a Conceptual Model Tool
by Katherine E. Raymond, Mike O’Kane, Mark Logsdon, Yamini Gopalapillai, Kelsey Hewitt, Johannes Drielsma and Drake Meili
Minerals 2025, 15(7), 752; https://doi.org/10.3390/min15070752 - 18 Jul 2025
Viewed by 261
Abstract
Life Cycle Impact Assessments (LCIAs) examine the environmental impacts of products using life cycle inventories (LCIs) of quantified inputs and outputs of a product through its life cycle. Currently, estimated impacts from mining are dominated by long-term metal release from tailings due to [...] Read more.
Life Cycle Impact Assessments (LCIAs) examine the environmental impacts of products using life cycle inventories (LCIs) of quantified inputs and outputs of a product through its life cycle. Currently, estimated impacts from mining are dominated by long-term metal release from tailings due to inaccurate assumptions regarding metal release and transport within and from mine materials. A conceptual model approach is proposed to support the development of a new database of LCI data, applying mechanistic processes required for the release and transport of metals through tailings and categorizing model inputs into ‘bins’. The binning approach argues for accuracy over precision, noting that precise metal release rates are likely impossible with the often-limited data available. Three case studies show the range of forecasted metal release rates, where even after decades of monitoring within the tailings and underlying aquifer, metal release rates span several orders of magnitude (<100 mg/L to >100,000 mg/L sulfate at the Faro Mine). The proposed tool may be useful for the development of a new database of LCI data, as well as to analyze mine’s regional considerations during designs for risk evaluation, management and control prior to development, when data is also scarce. Full article
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16 pages, 2021 KiB  
Article
The Cytoplasmic Tail of Ovine Herpesvirus 2 Glycoprotein B Affects Cell Surface Expression and Is Required for Membrane Fusion
by Colleen M. Lynch, Maria K. Herndon, McKenna A. Hull, Daniela D. Moré, Katherine N. Baker, Cristina W. Cunha and Anthony V. Nicola
Viruses 2025, 17(7), 994; https://doi.org/10.3390/v17070994 - 16 Jul 2025
Viewed by 371
Abstract
Ovine herpesvirus 2 (OvHV-2) causes the fatal veterinary disease malignant catarrhal fever (MCF). Fusion is an essential step in the host cell entry of enveloped viruses and is an important target for vaccine development. OvHV-2 cannot be propagated in vitro, so a robust [...] Read more.
Ovine herpesvirus 2 (OvHV-2) causes the fatal veterinary disease malignant catarrhal fever (MCF). Fusion is an essential step in the host cell entry of enveloped viruses and is an important target for vaccine development. OvHV-2 cannot be propagated in vitro, so a robust virus-free cell–cell membrane fusion assay is necessary to elucidate its entry mechanism. OvHV-2 cell–cell fusion requires three conserved herpesviral envelope glycoproteins: gB, gH, and gL. OvHV-2 fusion activity is detectable but low. We hypothesize that enhancing the cell surface expression of gB, which is the core herpesviral fusogen, will increase cell–cell fusion. We generated C-terminal truncation mutants of gB and determined their cell surface expression, subcellular distribution, and fusion activity. Two mutants, including one that lacked the entire cytoplasmic tail domain, failed to function in the cell–cell fusion assay, despite wild-type levels of surface expression. This suggests that the OvHV-2 gB cytoplasmic tail is critical for fusion. A gB mutant truncated at amino acid 847 showed increased surface expression and fusion relative to the wild type. This suggests that the robust fusion activity of gB847 is the result of increased surface expression. gB847 may be used in place of wild-type gB in an improved, more robust OvHV-2 fusion assay. Full article
(This article belongs to the Section Animal Viruses)
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23 pages, 9408 KiB  
Article
Pullout Behaviour of Snakeskin-Inspired Sustainable Geosynthetic Reinforcements in Sand: An Experimental Study
by Xin Huang, Fengyuan Yan and Jia He
Sustainability 2025, 17(14), 6502; https://doi.org/10.3390/su17146502 - 16 Jul 2025
Viewed by 286
Abstract
In recent years, there has been a growing interest in the frictional anisotropy of snake scale-inspired surfaces, especially its potential applications in enhancing the bearing capacity of foundations (piles, anchor elements, and suction caissons) and reducing materials consumption and installation energy. This study [...] Read more.
In recent years, there has been a growing interest in the frictional anisotropy of snake scale-inspired surfaces, especially its potential applications in enhancing the bearing capacity of foundations (piles, anchor elements, and suction caissons) and reducing materials consumption and installation energy. This study first investigated the frictional properties and surface morphologies of the ventral scales of Cantor’s rat snakes (Ptyas dhumnades). Based on the findings on the snake scales, a novel snakeskin-inspired geosynthetic reinforcement (SIGR) is developed using 3D-printed polylactic acid (PLA). A series of pullout tests under different normal loads (25 kPa, 50 kPa, and 75 kPa) were performed to analyze the pullout behavior of SIGR in sandy soil. Soil deformation and shear band thickness were measured using Particle Image Velocimetry (PIV). The results revealed that the ventral scales of Ptyas dhumnades have distinct thorn-like micro-protrusions pointing towards the tail, which exhibit frictional anisotropy. A SIGR with a unilateral (one-sided) layout scales (each scale 1 mm in height and 12 mm in length) could increase the peak pullout force relative to a smooth-surface reinforcement by 29% to 67%. Moreover, the peak pullout force in the cranial direction (soil moving against the scales) was found to be 13% to 20% greater than that in the caudal direction (soil moving along the scales). The pullout resistance, cohesion, and friction angle of SIGR all showed significant anisotropy. The soil deformation around the SIGR during pullout was more pronounced than that observed with smooth-surface reinforcement, which suggests that SIGR can mobilize a larger volume of soil to resist external loads. This study demonstrates that SIGR is able to enhance the pullout resistance of reinforcements, thereby improving the stability of reinforced soil structures, reducing materials and energy consumption, and is important for the sustainability of geotechnical engineering. Full article
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22 pages, 5061 KiB  
Article
Urolithin A Exhibits Antidepressant-like Effects by Modulating the AMPK/CREB/BDNF Pathway
by Yaqian Di, Rui Xue, Xia Li, Zijia Jin, Hanying Li, Lanrui Wu, Youzhi Zhang and Lei An
Nutrients 2025, 17(14), 2294; https://doi.org/10.3390/nu17142294 - 11 Jul 2025
Viewed by 496
Abstract
Background/Objectives: Urolithin A (UA), a gut-derived metabolite of ellagitannins or ellagic acid, has recently gained attention for its potential benefits to brain health. The present research aimed to assess the antidepressant-like properties of UA in both in vitro and in vivo models and [...] Read more.
Background/Objectives: Urolithin A (UA), a gut-derived metabolite of ellagitannins or ellagic acid, has recently gained attention for its potential benefits to brain health. The present research aimed to assess the antidepressant-like properties of UA in both in vitro and in vivo models and explored the molecular mechanisms underlying these effects. Methods: We investigated the antidepressant effects and mechanisms of UA in a model of corticosterone-induced damage to PC12 cells and in a model of chronic socially frustrating stress. Results: Our results demonstrate that UA treatment (5 and 10 μM) significantly alleviated cellular damage and inflammation in corticosterone (CORT)-treated PC12 cells. Furthermore, UA administration (50 and 100 mg/kg) significantly reduced immobility time in the mouse tail suspension test (TST) and forced swim test (FST), indicating its antidepressant-like activity. Additionally, treatment with UA led to the activation of the cAMP response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling cascade and triggered the activation of adenosine monophosphate-activated protein kinase (AMPK) during these processes. Importantly, pretreatment with AMPK-specific inhibitor Compound C abolished UA’s cytoprotective effects in PC12 cells, as well as its behavioral efficacy in the FST and TST, and its neurotrophic effects, highlighting the critical role of AMPK activation in mediating these effects. Furthermore, in the chronic social defeat stress (CSDS) mouse model, UA treatment (50 and 100 mg/kg) significantly alleviated depression-like behaviors, including reduced sucrose preference in the sucrose preference test, increased social avoidance behavior in the social interaction test, and anxiety-like behaviors, including diminished exploration, in the elevated plus maze test, suggesting the antidepressant-like and anxiolytic-like activities of UA. Moreover, UA treatment reversed elevated serum stress hormone levels, hippocampal inflammation, and the decreased AMPK/CREB/BDNF signaling pathway in the hippocampus of CSDS mice. Conclusions: Together, these results provide compelling evidence for UA as a viable dietary supplement or therapeutic option for managing depression. Full article
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17 pages, 2498 KiB  
Article
Lemongrass Alleviates Primary Dysmenorrhea Symptoms by Reducing Oxidative Stress and Inflammation and Relaxing the Uterine Muscles
by Sheikh Safeena Sidiq, Qaiser Jabeen, QurratUlAin Jamil, Muhammad Saeed Jan, Iram Iqbal, Fatima Saqib, Mohammed Aufy and Shahid Muhammad Iqbal
Antioxidants 2025, 14(7), 838; https://doi.org/10.3390/antiox14070838 - 8 Jul 2025
Viewed by 450
Abstract
Primary dysmenorrhea (PD) is characterized by lower abdominal spasms and painful cramps during menstruation in females with a normal pelvic anatomy. Cymbopogon citratus (DC.) Stapf, commonly known as lemongrass, is consumed in the form of herbal tea around the world. It has been [...] Read more.
Primary dysmenorrhea (PD) is characterized by lower abdominal spasms and painful cramps during menstruation in females with a normal pelvic anatomy. Cymbopogon citratus (DC.) Stapf, commonly known as lemongrass, is consumed in the form of herbal tea around the world. It has been traditionally used for menstrual disorders in several communities. This study aims to evaluate the traditional use of C. citratus for its efficacy in alleviating the symptoms of PD. C. citratus extract (CcE) was chemically characterized using HPLC and GCMS, which indicated the presence of several phenolic compounds and long-chain fatty acids. The anti-inflammatory activity of CcE was assessed by COX-I, COX-II, and 5-LOX enzyme inhibition with IC50 values of 143.7, 91.7, and 61.5 µg/mL, respectively, and showed good total antioxidant capacity and free radical scavenging activity. PD was induced in female Wistar rats by administering estradiol valerate followed by oxytocin to induce PD symptoms. CcE efficacy was assessed at 30, 100, and 300 mg/kg concentrations and compared with ibuprofen. CcE 300 mg/kg reduced abdominal contortions and inflammation in the rat uterus. The inflammatory (COX-II, TNFα and IL-10) and oxidative stress (TAC, TOS, MDA and SOD) markers in uterine tissue homogenate were also improved. An in vivo analgesic assessment through hot-plate, tail-flick, and acetic acid-induced writhing assays showed good analgesic activity by CcE, while ex vivo experiments described tocolytic effects in rat uterine muscles. CcE alleviates PD by its antioxidant, anti-inflammatory, analgesic, and tocolytic effects. Full article
(This article belongs to the Section Natural and Synthetic Antioxidants)
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16 pages, 3918 KiB  
Article
Improvements in Wettability and Tribological Behavior of Zirconia Artificial Teeth Using Surface Micro-Textures
by Yayun Liu, Guangjie Wang, Fanshuo Jia, Xue Jiang, Ning Jiang, Chuanyang Wang and Zhouzhou Lin
Materials 2025, 18(13), 3117; https://doi.org/10.3390/ma18133117 - 1 Jul 2025
Viewed by 319
Abstract
Zirconia ceramics are promising materials for restoration and are widely used in the field of artificial teeth. However, wear resistance affects the longevity of artificial teeth. In this study, peacock tail feather micro-textures and groove micro-textures are prepared on the surfaces of zirconia [...] Read more.
Zirconia ceramics are promising materials for restoration and are widely used in the field of artificial teeth. However, wear resistance affects the longevity of artificial teeth. In this study, peacock tail feather micro-textures and groove micro-textures are prepared on the surfaces of zirconia ceramics via the laser ablation technique to improve their tribological properties. The effects of micro-textures on the surface wettability and tribological properties of zirconia ceramics are studied. The micro-textures improve the surface wettability and tribological properties of zirconia ceramics. The average coefficient of friction of peacock tail feather micro-textured samples decreases by 53% compared to that of the samples without micro-textures. Different operating conditions affect the friction properties of zirconia ceramics. The samples have the best friction performance when the rotational speed, load, and acid/alkaline environment are 200 r/min, 15 N, and weakly alkaline, respectively. Furthermore, the mechanism by which surface micro-textures reduce frictional wear is as follows: the textured grooves store debris, and the bottom edge of the textured groove acts as a cutting tool to cut debris, preventing debris from scratching the surface. The micro-textures store lubricant and form a liquid film on the ceramic surface to reduce wear. Full article
(This article belongs to the Section Biomaterials)
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26 pages, 9572 KiB  
Article
Geochemical Characteristics and Risk Assessment of PTEs in the Supergene Environment of the Former Zoige Uranium Mine
by Na Zhang, Zeming Shi, Chengjie Zou, Yinghai Zhu and Yun Hou
Toxics 2025, 13(7), 561; https://doi.org/10.3390/toxics13070561 - 30 Jun 2025
Viewed by 289
Abstract
Carbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soils and sediments, particularly [...] Read more.
Carbonaceous–siliceous–argillaceous rock-type uranium deposits, a major uranium resource in China, pose significant environmental risks due to heavy metal contamination. Geochemical investigations in the former Zoige uranium mine revealed elevated As, Cd, Cr, Cu, Ni, U, and Zn concentrations in soils and sediments, particularly at river confluences and downstream regions, attributed to leachate migration from ore bodies and tailings ponds. Surface samples exhibited high Cd bioavailability. The integrated BCR and mineral analysis reveals that Acid-soluble and reducible fractions of Ni, Cu, Zn, As, and Pb are governed by carbonate dissolution and Fe-Mn oxide dynamics via silicate weathering, while residual and oxidizable fractions show weak mineral-phase dependencies. Positive Matrix Factorization identified natural lithogenic, anthropogenic–natural composite, mining-related sources. Pollution assessments using geo-accumulation index and contamination factor demonstrated severe contamination disparities: soils showed extreme Cd pollution, moderate U, As, Zn contamination, and no Cr, Pb pollution (overall moderate risk); sediments exhibited extreme Cd pollution, moderate Ni, Zn, U levels, and negligible Cr, Pb impacts (overall extreme risk). USEPA health risk models indicated notable non-carcinogenic (higher in adults) and carcinogenic risks (higher in children) for both age groups. Ecological risk assessments categorized As, Cr, Cu, Ni, Pb, and Zn as low risk, contrasting with Cd (extremely high risk) and sediment-bound U (high risk). These findings underscore mining legacy as a critical environmental stressor and highlight the necessity for multi-source pollution mitigation strategies. Full article
(This article belongs to the Special Issue Assessment and Remediation of Heavy Metal Contamination in Soil)
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22 pages, 5365 KiB  
Article
Machine Learning-Based Analysis of Heavy Metal Migration Under Acid Rain: Insights from the RF and SVM Algorithms
by Jie Yao, Jianping Qian and Dongru Ji
Minerals 2025, 15(6), 663; https://doi.org/10.3390/min15060663 - 19 Jun 2025
Viewed by 413
Abstract
Acid rain alters soil chemistry significantly and is a key driver of heavy metal pollution. This study investigates the environmental impact of acid rain-induced heavy metal migration in the Siding Lead–Zinc mining area in south China. Tailings, surrounding soils, and riverbed sediments were [...] Read more.
Acid rain alters soil chemistry significantly and is a key driver of heavy metal pollution. This study investigates the environmental impact of acid rain-induced heavy metal migration in the Siding Lead–Zinc mining area in south China. Tailings, surrounding soils, and riverbed sediments were examined through simulated acid rain soil column leaching experiments. Leachate parameters—including pH, redox potential (Eh), total dissolved solids (TDSs) and heavy metal concentrations—were used to develop machine learning models (Random Forest and Support Vector Machine) to quantify the influence of environmental factors on metal migration. The results showed that leachates were generally alkaline and reductive after leaching, with Cd, Pb, and Zn as the dominant migrating metals. Leachates from tailings and nearby soils exceeded safe drinking water standards, with significantly higher cumulative metal release than other samples. The RF model outperformed the SVM model in predicting heavy metal concentrations. Feature importance analysis revealed that, beyond sample characteristics, pH and Eh were critical factors driving metal migration. Zn and Cd showed strong sensitivity to these parameters, with pH and Eh contributing over 80% to their migration. The findings highlight that acid rain can enhance the solubility and migration of heavy metals, posing a serious threat to the quality of surrounding water and underscoring the requirement for effective mitigation strategies to protect the ecological environment in mining areas. Full article
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24 pages, 6692 KiB  
Article
Application of Flotation Tailings as a Substitute for Cement in Concrete Structures for Environmental Protection and Sustainable Development—Part I: Sulfide Neutralization
by Vanja Đurđevac, Novica Staletović, Lidija Đurđevac Ignjatović, Violeta Jovanović, Nikola Vuković and Vesna Krstić
Materials 2025, 18(12), 2804; https://doi.org/10.3390/ma18122804 - 14 Jun 2025
Viewed by 452
Abstract
Flotation tailings (FT), as a product of the exploitation and processing of copper ore, represent a significant environmental and health risk due to the high content of heavy metals and sulfide compounds. Contemporary concepts of sustainable development and circular economy increasingly emphasize the [...] Read more.
Flotation tailings (FT), as a product of the exploitation and processing of copper ore, represent a significant environmental and health risk due to the high content of heavy metals and sulfide compounds. Contemporary concepts of sustainable development and circular economy increasingly emphasize the need for rational use of resources and minimization of all types of waste, including mining waste. In this context, the reuse of flotation tailings in the construction industry represents a significant step towards closing the material flow in the mining and construction sectors. In order to reduce the negative impact of FT on the environment, the possibility of its application as a substitute for a portion of cement in the production of concrete was investigated. The main challenge is to reduce the negative impact of sulfides, originating from sulfide compounds, in order to achieve the desired concrete quality. Limestone aggregates of different size fractions (0/4, 4/8, 8/16 mm) were used for sulfide neutralization. Pyrite concentrate was used as a sulfide source, which together with FT provides the mixtures FT-7, FT-14, FT-25, and FT-40, with sulfur contents of 7.56, 13.84, 25.02, and 39.82%, respectively. FT mixtures were used as a substitute for Portland cement (PC) in the preparation of concrete. Test methods included XRD (X-ray diffraction), XRF (X-ray fluorescence), SEM (scanning electron microscopy), LP (leaching procedure), TCLP (toxicity characterization leaching procedure), assessment of acid eluate generation potential (AP—acid potential, NP—neutralization potential, and NNP—net neutralization potential), NEN (determination of heavy metals in cured concrete eluate), and UCS (uniaxial compressive strength of cured concrete). The results showed that the chemical characteristics of FT, as well as the chemical and mechanical properties of hardened concrete, allow the efficient use of these tailings in concrete mixes, which significantly utilizes FT, reduces the generation of mining waste, and contributes to the reduction of the negative impact on the environment and achieving sustainable development in mining. Full article
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