Search Results (2,952)

Per- and polyfluoroalkyl substances (PFASs) include thousands of fluorinated organic compounds of anthropogenic origin. Their extensive use, combined with their high stability, has led to the widespread contamination of water and soil resources. Here, single-step foam fractionation enhanced soil washing was carried out for the remediation of PFAS-contaminated soil. Concentrations of target Perfluoroalkyl Carboxylic Acids (PFCAs) and Perfluoroalkane Sulfonic Acids (PFSAs) were monitored in foam and leachate along the duration of the treatment. Among PFCAs, only long-chain compounds peaked in foam at the beginning of the treatment. This was consistent with the increase in the sorption affinity to the air–water interface with chain length. The same behavior was observed also in PFSAs by comparing PFHXs, PFHpS and PFOS. The fraction of PFCAs still in the leachate after 40 min of treatment was found to decrease with chain length, with PFSAs showing a similar trend. PFAS removal significantly increased with soil particle size, ranging from 48.2 ± 3.2% (fraction < 0.063 µm) to 64.1 ± 1.9% (fraction > 2 mm). Final mass balance analyses detail PFAS distribution among soil, leachate, and foam, providing valuable information for the additional treatment required to destroy the PFAS load extracted from the contaminated soil. Full article

Stone heritage deteriorates through physical, chemical, and biological processes driven by water, climate, and microbial colonization. Multifunctional polymeric coatings combining hydrophobic and antimicrobial moieties have emerged as a promising conservation strategy, yet a substantial gap remains between laboratory innovation and real-world performance. This review critically examines advances from 2021 to 2026, covering wetting theory, antimicrobial mechanisms, and material architectures, including molecularly integrated systems, Sol–Gel hybrids, nanocomposites, and layered systems. Long-term studies on the Aurelian Walls in Rome and stone in Reims show that biocidal efficacy typically declines within one to two years despite the chemical persistence of the coatings. In parallel, hydrophobic performance often deteriorates over time due to UV exposure, particulate deposition, and surface chemical changes, leading to increased wettability and reduced protective efficiency. Substrate porosity governs durability and visual compatibility (ΔE* < 5 threshold), while treatments can reshape microbial communities, favoring stress-tolerant meristematic fungi. Regulatory pressure on fluorinated compounds drives the development of more sustainable alternatives. Emerging directions include stimuli-responsive systems, self-healing materials, slippery interfaces, and precision polymer architectures. However, future progress will depend on tailoring formulations to major lithotypes, improving compatibility with porous substrates, and validating performance through standardized accelerated aging and multi-year field trials. Bridging laboratory design with environmental exposure data and conservation practice will be essential for achieving durable and culturally acceptable protection strategies. Full article

Butyrate, a short-chain fatty acid produced by the fermentation of soluble dietary fiber by gut bacteria, also functions as a histone deacetylase inhibitor known to induce apoptosis and promote differentiation in colon tumor cells. During tumorigenesis, cancer cells undergo metabolic reprogramming to meet energetic and biosynthetic demands, increasing glycolytic metabolism and reducing oxidative metabolism—a phenomenon known as the Warburg effect. This study aimed to evaluate the impact of butyrate on the aggressiveness-related metabolic phenotype of three colon cancer cell lines (LS1034, C2BBe1, and WiDr). Butyrate’s effects were assessed through fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) uptake, flow cytometry analysis of cytoplasmic and membrane expression of glucose transporters (GLUT1, GLUT3, GLUT5, and GLUT12), lactate production, and analysis of Krebs cycle turnover and glycolysis–Krebs cycle coupling using nuclear magnetic resonance isotopomer profiling. [¹⁸F]FDG uptake decreased in C2BBe1 and WiDr cells, whereas an opposite response was observed in LS1034 cells, which also exhibited reduced GLUT5 expression. These uptake patterns were consistent with lactate production measurements, and an enhancement of oxidative metabolism was detected in C2BBe1 and WiDr cells. Although butyrate was consumed by all three cell lines, its metabolic handling appeared to differ in LS1034 cells, possibly reflecting cytotoxic stress and/or distinct metabolic regulation mechanisms. Overall, these findings indicate that butyrate exerts cell-line-dependent metabolic effects in colorectal cancer cells. In C2BBe1 and WiDr cells, butyrate exposure was broadly consistent with the attenuation of glycolytic/Warburg-associated features, whereas LS1034 cells displayed a divergent response and were interpreted separately. These data support further investigation of butyrate as a modulator of colorectal cancer cell metabolism, while highlighting the heterogeneity of metabolic responses across tumor models. Full article

A nanostructured sensing platform based on electrospun functionalized multi-walled carbon nanotubes/poly(3-aminobenzylamine) (FMWCNTs/P3ABA) was developed for the electrochemical detection of dopamine (DA) on fluorine-doped tin oxide (FTO) glass substrate. The electrochemical characteristics of the electrodes were investigated by chronocoulometry (CC) and cyclic voltammetry (CV) in phosphate-buffered saline solution containing K₃[Fe(CN)₆] as a redox mediator. The zeta potential analysis confirmed the presence of a stable surface charge that favors electrostatic interaction with DA molecules. The DA detection was performed in human urine by differential pulse voltammetry (DPV) over a potential of −0.2 to 0.8 V and at scan rate of 5 mV s⁻¹, where the FMWCNTs/P3ABA nanofiber electrode exhibited a high sensitivity of 1.502 µA cm⁻² nM⁻¹, a linear detection range of 10–500 nM (R² = 0.992), and a limit of detection of 1.753 nM. The sensor exhibited stable and reproducible responses, and the fibrous composite effectively discriminated DA from common electroactive interferents, including ascorbic acid, uric acid, creatinine, and glucose. Furthermore, reliable dopamine quantification in human urine samples demonstrates the strong potential of the electrospun FMWCNTs/P3ABA composite nanofiber platform for practical bioanalytical and non-invasive sensing applications in the future. Full article

Two-dimensional Ti₃C₂O₂ MXene has emerged as a promising electrode material for non-enzymatic glucose sensing due to its metallic conductivity and biocompatibility. However, the atomic-scale sensing mechanism remains unclear. This DFT study uses the PBE functional with the D3(BJ) dispersion correction to elucidate glucose–MXene interactions under idealized vacuum conditions. Pristine Ti₃C₂O₂ shows metallic behavior with a density of states of about 8.2 states per electron volt at the Fermi level, dominated by Ti 3d states. β-d-glucose adsorbs onto the surface through hydrogen bonding, with an adsorption energy of −0.82 eV at a separation distance of 2.8 angstroms. Bader analysis indicates a transfer of about 0.15 electrons from MXene to glucose, resulting in a Fermi level shift of about −0.15 eV and an 18% reduction in the density of states at the Fermi level. These changes correspond to an estimated sensitivity of approximately 0.6 μA mM⁻¹ cm⁻² and a detection limit of about 17 µM, consistent with reported experimental performance of MXene-based sensors. Comparative adsorption calculations for common sweat interferents yield −0.45 eV for lactate and −0.25 eV for urea, indicating weaker interfacial affinity than glucose; these values reflect thermodynamic binding strength and possible surface occupation rather than definitive electrochemical selectivity, which additionally depends on redox potential, electron-transfer kinetics, and operating bias. We acknowledge three main limitations: first, the model considers only pure oxygen termination rather than mixed oxygen, hydroxyl, and fluorine terminations; second, the calculations are performed under vacuum rather than in aqueous conditions; third, the study is based on static zero kelvin structures rather than finite temperature dynamics. Despite these idealizations, the results provide baseline mechanistic insights to support rational design of MXene-based glucose sensors. Full article

Background: Per- and polyfluoroalkyl substances (PFAS) represent a large class of synthetic fluorinated compounds characterized by highly stable carbon–fluorine bonds that confer exceptional environmental persistence and bioaccumulative properties. Although regulatory measures have restricted the production of several PFAS, including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), their environmental persistence continues to maintain widespread human exposure, while newly introduced replacement compounds raise additional toxicological concerns. Notably, the recent evidence demonstrating PFAS-induced alterations in key cardiac ion channel activity and electrocardiographic parameters suggest potential electrophysiological mechanisms that may contribute to arrhythmogenesis and cardiac arrhythmias including the most frequent one, atrial fibrillation (AF). Methods: We conducted a narrative literature review of experimental, epidemiological, and mechanistic studies investigating and reporting the cardiovascular, electrophysiological, and potential arrhythmogenic effects of PFAS. Results: Available evidence indicates that PFAS exposure is associated with alterations in cardiac electrophysiology, including modulation of ion channel activity (notably sodium, calcium, and potassium channels), disruption of calcium handling, and changes in electrocardiographic parameters such as QT interval prolongation, which are key contributors to arrhythmogenesis and AF. Conclusions: This review highlights the need for improved understanding of PFAS-induced electrophysiological alterations, to clarify the role of PFAS in cardiac arrhythmias including AF. Full article

Phosphatic deposits from the Lower Cambrian Pedroche Formation (Sierra de Córdoba, Spain) provide key insights into early diagenetic mineralization processes during the Cambrian radiation. This study applies an integrated multi-analytical approach combining Raman spectroscopy, SEM–EDS, LA-ICP-MS, and ToF-SIMS to investigate mineralogical, elemental, and molecular signatures of phosphatized bioclastic carbonates and associated siliciclastic facies from the Los Lagares-1 borehole. Results reveal a systematic phosphatization gradient from carbonate-dominated skeletal rims to phosphate-rich interiors composed of carbonate fluorapatite with variable carbonate and hydroxyl substitution. Trace-element systematics and REE patterns indicate seawater-influenced phosphogenesis under suboxic porewater conditions, coupled to iron reduction and early diagenetic clay mineral formation. In contrast, the siliciclastic siltstone facies preserves poorly crystalline phosphate phases associated with detrital aluminosilicates and chlorite, reflecting distinct porewater chemistry and crystallization kinetics. ToF-SIMS mapping demonstrates spatial coupling between fluorine and phosphate within fossil structures, confirming fluorapatite formation and localized organic matter entombment. These results highlight the strong control of host lithology on phosphate crystallization pathways and trace-element redistribution, and provide new constraints on microbially mediated phosphogenesis in restricted Early Cambrian reef–lagoon systems along the northern Gondwanan margin. Full article

There is a strong and growing need for low environmental impact, fluorine-free finishes that deliver durable water repellency and stain resistance to leather while preserving its original appearance. This work successfully addresses this need by introducing a simple, robust, and scalable two-step coating strategy that endows leather surfaces with excellent hydrophobic and self-cleaning properties. The process relies on a straightforward spray application of functionalized silica nanoparticles followed by a hydrophobic silane, namely hexadecyltrimethoxysilane (HDTMS), enabling precise control over surface properties through the number of applied layers. Comprehensive characterization by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS) confirmed the effective formation and uniformity of the coating. Performance testing demonstrated excellent functional outcomes: the optimized coating achieved a water contact angle (WCA) of 128° and maintained values above 125° even after abrasion, highlighting its durability. Treated leather exhibited resistance to common liquid stains such as tea and coffee, maintaining a clean surface. These functional gains were achieved without compromising the leather’s natural look or soft feel, even after multiple coating cycles. This work delivers a fluorine-free solution offering an effective route to high-value water- and stain-resistant leather finishes that respect both environmental and aesthetic requirements. Full article

To address the drag reduction requirements of superhydrophobic surface coatings for underwater vehicle hulls, this study designed a synthesis method based on resin substrate modification and filler modification according to superhydrophobic coating synthesis techniques. Three types of superhydrophobic microstructured surface coatings were prepared: polyurethane resin, silicone resin, and fluororesin. The coatings were fabricated by incorporating fluorine-modified SiO₂ nanoparticles into the modified resin matrices to construct hierarchical micro/nanostructures. The main components and synthesis processes for each coating were determined. Performance tests were conducted to evaluate mechanical properties (thickness, hardness, adhesion, wear resistance), functional characteristics (surface morphology, static/dynamic hydrophobic angles), and environmental resistance (seawater immersion, salt spray stability, thermal stability). Five surface coating test plans for underwater vehicle hull models were proposed, and drag reduction experiments were carried out to compare total drag, drag coefficient, and drag reduction rate across coating plans. Experimental results indicated that the silicone resin superhydrophobic coating with F660 + 8% SiO₂ exhibited the best comprehensive performance, while the PU + 6% SiO₂ superhydrophobic coating achieved optimal drag reduction at speeds below 9 m/s, meeting the performance criteria for underwater vehicle hull applications. Full article

The global rise in the incidence and severity of invasive fungal infections, particularly among immunocompromised and immunodeficient patients, has created an urgent need for rapid and accurate diagnostic techniques. Therefore, fungal-specific positron emission tomography imaging agents are increasingly in demand, as they offer the potential for early-stage detection of fungal infections. Recently, 2-deoxy-2-[¹⁸F]fluorocellobiose ([¹⁸F]FCB), a fluorine-18-labeled analog of cellobiose that is selectively metabolized by fungal pathogens possessing cellulose-degrading mechanisms (cellulolytic), was developed for the targeted imaging of Aspergillus infections. However, the final [¹⁸F]FCB contained less than 2% unreacted 2-deoxy-2-[¹⁸F]fluoroglucose ([¹⁸F]FDG), which can potentially interfere with image interpretation. Accordingly, this study aims to eliminate residual [¹⁸F]FDG from the final product by enzymatically converting it to [¹⁸F]FDG-6-phosphate through hexokinase-mediated phosphorylation. A Trasis AllInOne (Trasis AIO) module was used to automate the radiolabeling procedure. The reagent vials contain [¹⁸F]FDG, glucose-1-phosphate, cellobiose phosphorylase, adenosine triphosphate (ATP), and hexokinase. A Sep-Pak cartridge was used to purify the tracer. The overall radiochemical yield was 45–50% (n = 3, decay-corrected) in a 40 min synthesis time, with a radiochemical purity of >99% (no detectable [¹⁸F]FDG). This is a highly reliable protocol to produce current good manufacturing practice (cGMP)-compliant [¹⁸F]FCB for clinical PET imaging. Full article

The persilylated Si₃–Si₇ analogues of the C₃–C₇ aromatic molecules and ions with all hydrogen or all fluorine atoms at silicon have been calculated at high levels of theory, up to MP2/aug-cc-pVTZ for all species and CCSD/6-311++G** for Si₃ and Si₄ species, both in the gas phase and in a polar solvent (water). The aromaticity of the calculated species was estimated using structural, energetic, and NMR criteria. (SiF)₃⁺ cations are more aromatic than (SiH)₃⁺ by the NICS (nuclear-independent chemoical shift) but less aromatic by the ASE (aromatic stabilization energy) criterion. Dications (SiX)₄²⁺ are planar (X = H) or slightly puckered (X = F); the ASE decreases by 4–5 kcal/mol upon going from gas to solution, or from X = H to X = F. Dianions (SiX)₄²⁻are nonplanar and antiaromatic. The ASE for the slightly distorted-from-planarity anion Si₅H₅⁻ is ~53 kcal/mol, vs. 85 kcal/mol for its carbon analogue. The structure of Si₆X₆ molecules strongly depends on the level of calculations. The NICS and ASE values have been calculated for planar Si₆H₆ and (SiH)₇⁺ but not for strongly distorted Si₆F₆ and (SiF)₇⁺ species. Full article

Both Co-free and lithium- and manganese-rich layered oxide Li(Li_0.2Mn_xNi_yFe_z)O₂ (MNF) cathodes have recently attracted attention in lithium-ion battery (LIB) research due to their high capacities of over 250 mAhg⁻¹, as well as being more eco-friendly and inexpensive than commercial NMC and LiCoO₂. However, they still suffer from lower experimental capacity as well as capacity decay, voltage fade, poor rate capability, and thermal instability. In this paper, fluorine (F)-doped Li_1.2(Mn_0.5Ni_0.2Fe_0.1)O_2(1−x)F_2x (MNF502010, x = 0, 0.025, 0.05, 0.075, 0.1) cathode materials have been synthesized in the nanoscale via sol–gel and subsequent solid-phase calcination to address some of these problems. The resulting 5% F-doped MNF502010 cathode demonstrates the advantage of fluorine doping, which makes a significant contribution to the formation of a well-ordered layer structure with a minimal LiM₂O₄ spinel phase as an impurity. This composition achieves an initial discharge capacity of 252 mAhg⁻¹ (1C = 250 mAhg⁻¹) and a 156 mAhg⁻¹ discharge capacity at 0.3 C on the 100th discharge, with an average voltage fade of 0.24 V. The optimization of fluorine composition results in an enhancement in the activation of the Li₂MnO₃-type monoclinic phase, as well as an increase in the electronic conductivity compared to the fluorine-free cathode. To understand the structural origin of this improved performance, X-ray absorption spectroscopy (XAS) measurements were carried out on pristine and cycled MNF electrodes. Full article

Water scarcity compels wastewater reuse, but lax discharge standards generate a regulatory mirage, misleading the public about safety. Here, “regulatory mirage” refers to situations where formal compliance with discharge standards creates a false perception of safety while ecological risks and degradation persist. Despite formal compliance, treated effluent severely harms Iran’s effluent-dependent Kashaf River, driving eutrophication, salinization, and the downstream transport of unregulated contaminants of emerging concern, including fluorinated substances (PFAS) and pharmaceuticals. These pressures extend beyond the river channel to adjacent natural wetlands, which act as de facto nature-based treatment systems yet are progressively transformed into sacrificial sinks for excess nutrients, salts, heavy metals, and micropollutants. By benchmarking the Iranian Wastewater Discharge Standards (IWDS) against international guidelines (WHO, EU, FAO), this study quantifies a “Permissibility Gap” frequently greater than 10 for key parameters such as BOD₅, nutrients, and trace metals, revealing how concentration-based limits ignore cumulative mass load and mixture toxicity at the basin scale. The Kashaf River case demonstrates that current end-of-pipe regulation undermines both natural wetlands and planned nature-based solutions, including constructed wetlands, in arid regions where effluent reuse is unavoidable. The study argues that aligning discharge standards with global benchmarks, adopting mass-based permits, and explicitly regulating contaminants of emerging concern are prerequisites for truly safe wastewater reuse and for protecting wetland ecosystems in effluent-dependent basins. This study shows that permissive, concentration-based discharge standards in effluent-dependent basins create a regulatory mirage that accelerates river and wetland degradation, and that stricter, mass-based limits are essential for safe wastewater reuse. Full article

Sodium metal batteries (SMBs) are promising energy storage systems, yet their practical application is hindered by unstable solid electrolyte interphases (SEIs) and safety issues associated with flammable electrolytes. Although the flame-retardant solvent trimethyl phosphate (TMP) is widely used in rechargeable batteries, its application in SMBs remains constrained due to uncontrolled and accumulated parasitic reactions with sodium metal anodes. Here, we propose a novel synergistic strategy that combines a fluorinated additive (FEC) with a low-cost, high-concentration NaClO₄ to stabilize the electrode–electrolyte interface in TMP-based electrolytes. This approach enables the formation of a robust, NaF-rich SEI while restructuring the Na⁺ solvation sheath to coordinately trap TMP molecules, thereby suppressing parasitic reactions between sodium metal and TMP. As a result, the Na|Na₃(VOPO₄)₂F cell achieves exceptional cycling stability with 89.04% capacity retention over 1000 cycles at 1C. This work provides a cost-effective and practical pathway toward safe and long-lasting SMBs using non-flammable phosphate electrolytes. Full article

The HVAC/R sector in Europe is undergoing significant transformation driven by climate policy, technological innovation, and increasing digitalization of industrial services. This study examines the sustainability and digital transformation of the Slovak business-to-business (B2B) HVAC/R market in the context of EU F-gas regulation and emerging workforce constraints. The research applies a qualitative–interpretive design supported by structured secondary-data analysis, a review of European and Slovak regulatory frameworks, comparative benchmarking against selected European markets, and exploratory semi-structured interviews with industry professionals. The analysis indicates that regulatory pressure associated with the phase-down of fluorinated greenhouse gases, rising demand for energy-efficient systems, and the growing role of digital communication channels are reshaping procurement behaviour and market competition. At the same time, the sector faces structural barriers, particularly the limited availability of certified technicians and uneven digital adoption among small and medium-sized enterprises. The findings suggest that firms integrating transparent sustainability communication, environmental performance indicators, and digital engagement strategies can strengthen their competitive positioning within the evolving European HVAC/R ecosystem. Full article