Search Results (454)

This study was performed to elucidate the mechanism underpinning the nodal swelling induced by equinatoxin II (EqtII), a cation-selective pore-forming toxin derived from the sea anemone Actinia equina. Experiments were conducted using frog myelinated nerve fibers as a model system. Application of EqtII led to an approximately two-fold increase in the nodal volume of myelinated axons, but only when extracellular Ca²⁺ was present. Replacing extracellular Cl⁻ with isethionate had no measurable effect on this response, whereas substitution of NaCl with either sucrose or LiCl, an established Na⁺/Ca²⁺ exchanger (NCX) inhibitor, abolished the swelling. The persistence of the effect in the presence of tetrodotoxin indicates that voltage-gated Na⁺ channels are not involved in the underlying mechanism. Our data suggest that Ca²⁺ influx through EqtII-induced membrane pores raises intracellular Ca²⁺ levels, thereby stimulating the NCX in its forward-operating mode. This process promotes Ca²⁺ extrusion in exchange for Na⁺ entry. The resulting accumulation of intracellular Na⁺ increases osmotic pressure within the axon, leading to water influx and nodal swelling. Full article

Antimicrobial resistance genes threaten the effective treatment of infectious diseases, underscoring the importance of their control in line with the EU One Health policy. Wastewater treatment plants are recognized hotspots for antimicrobial resistance. We assessed whether multi-channel mixed-matrix membranes (MCMMMs)—polyethersulfone (PES)/polyvinylpyrrolidone (PVP) ultrafiltration membranes with embedded activated carbon—can concurrently reduce microorganisms and extracellular DNA in wastewater effluent, building on prior reports of micropollutant removal. We evaluated the performance of MCMMMs in removing Escherichia coli and Saccharomyces cerevisiae as model organisms, as well as colony-forming units (CFUs) from wastewater effluent at a transmembrane pressure of 1 bar with a filtration area of 66 cm² over 1 h. DNA was extracted from wastewater effluent following filtration and analyzed to assess changes in microbial community composition. MCMMMs achieved log₁₀ reductions of 5.47 ± 0.42 (Escherichia coli), 5.99 ± 0.46 (Saccharomyces cerevisiae), and 2.79 ± 0.31 (wastewater CFU); reductions by pure PES/PVP membranes were comparable: higher for Escherichia coli and wastewater CFUs, lower for Saccharomyces cerevisiae. Amplicon sequencing showed altered relative abundances in wastewater effluent. Collectively, these findings demonstrate the potential of MCMMMs to simultaneously remove microorganisms, extracellular DNA, and micropollutants, highlighting their suitability for water treatment applications within the One Health framework. Full article

Magnetic resonance techniques have evolved beyond conventional proton-based imaging, enabling access to a broader range of nuclei that provide complementary structural, functional, and molecular information. This review presents a comprehensive overview of multinuclear NMR and MRI in solid and soft materials as well as in biomedical applications, with particular emphasis on ¹H, ¹³C, ³¹P, ²³Na, and ¹⁹F nuclei. Proton-based methods remain the foundation of magnetic resonance due to their high sensitivity and widespread applicability, offering insights into molecular mobility, hydration, and microstructural heterogeneity. In contrast, heteronuclear approaches enable more specific characterization of chemical structure (¹³C), phosphorus-containing functional groups and membranes (³¹P), ionic homeostasis and transport (²³Na), and exogenous tracers with negligible biological background (¹⁹F). Together, these techniques extend magnetic resonance from primarily anatomical imaging toward functional, metabolic, and molecular-level analysis. The review further discusses key hardware aspects, including magnetic field strength and radiofrequency coil design, highlighting the trade-offs between low- and high-field systems and the growing importance of multinuclear coil architectures. For example, because ¹H, ²³Na, ³¹P, and ¹⁹F resonate at different Larmor frequencies, multinuclear experiments require dedicated or multi-tuned RF coils that balance sensitivity, field homogeneity, and decoupling between channels. Mechanisms of contrast generation are examined in detail, distinguishing between endogenous sources—such as water, ions, and metabolites—and exogenous contrast agents, including gadolinium-, manganese-, and fluorine-based compounds, as well as targeted and theranostic platforms. A comparative framework of endogenous and exogenous signals is presented, emphasizing their complementary roles in balancing safety, specificity, and sensitivity. Finally, the opportunities and challenges of multinuclear magnetic resonance are critically evaluated, including limitations in sensitivity, signal-to-noise ratio, data interpretation in heterogeneous systems, and technical complexity. Emerging directions such as ultrahigh-field imaging, advanced RF technologies, hyperpolarization, and artificial intelligence-assisted reconstruction are discussed as key drivers for future development. Overall, multinuclear NMR and MRI represent a powerful and expanding toolbox for probing complex material and biological systems, with the potential to significantly enhance diagnostic capabilities and deepen our understanding of structure–function relationships across multiple scales. Full article

To mitigate the gas–liquid mass-transfer bottleneck in anion-exchange membrane water electrolysis (AEMWE), a 3D multiphysics numerical model was developed to systematically investigate the regulatory effects of gradient porosity (GPD) and gradient pore-size distribution (GPSD) on anode reaction kinetics and cell polarization. Single-factor analysis reveals that increasing the GPD/GPSD from the membrane side toward the flow channel side effectively reduces activation overpotential due to the high specific surface area of small pores near the membrane, while simultaneously lowering mass-transfer resistance through high porosity and large pores near the flow channel. Conversely, a decreasing gradient leads to localized gas stagnation and uneven mass transfer, deteriorating cell performance. Furthermore, an innovative synergistic design is proposed featuring a simultaneous linear increase in porosity (0.6 to 0.9) and pore diameter (0.11 to 0.17 mm). This configuration achieves a cell voltage of only 1.812 V at 1100 mA/cm² (1 mol/L KOH, 80 °C), approximately 40 mV lower than that of conventional uniform structures, thereby significantly reducing energy consumption at high current densities. This study provides a mechanistic framework for the precise architectural design of high-performance AEMWE electrodes, highlighting the importance of spatial heterogeneity in optimizing two-phase transport. Full article

Perovskite mixed proton–electron hydrogen-permeable membranes have been widely applied in the field of membrane separation due to their 100% selectivity for hydrogen separation. La_5.5WO_11.25-δ-La_0.87Sr_0.13CrO_3-δ (LWO-LSF) four-channel hollow fiber membranes were prepared by the phase inversion and sintering technique using a one-step thermal processing (OSTP) approach. The effects of temperature, feed gas concentration, sweep gas flow, permeation mode, and water vapor on hydrogen flux were systematically investigated. At 900 °C, the hydrogen permeation flux of 50% H₂/N₂ feed from the shell side to the lumen side was 0.613 mL·min⁻¹·cm⁻², which was 62.59% higher than that from the lumen side to the shell side. The enhanced hydrogen permeation performance is attributed to the lower gas mass transfer resistance under shell-side feeding. Under humidified conditions on the sweep side, the hydrogen flux increased by an additional 3.42%. The presence of water vapor increased the number of proton carriers, effectively enhancing proton–electron-coupled transport and thereby increasing the hydrogen permeation flux. Full article

Solid-contact ion-selective electrodes (SC-ISEs) are typically constructed using ion-selective membrane (ISM)-based configurations. However, such structures often suffer from water-layer formation and the weak mechanical stability of the ISM. Herein, we report an ISM-free K⁺-SC-ISE based on a Prussian blue analogue transducer, KMnFe(CN)₆, eliminating the need for a conventional ionophore-based ISM layer. KMnFe(CN)₆ was synthesized via a one-step citrate-assisted co-precipitation method. The material functions as a bifunctional transducer, in which the open framework structure with ion-transport channels enables selective K⁺ recognition, while the redox-active Mn centers facilitate ion-to-electron transduction. The fabricated KMnFe(CN)₆-based K⁺ sensor exhibits a near-Nernstian response with a sensitivity of 52.3 ± 1.0 mV dec⁻¹ and a rapid response time of 25 s. The linear range and limit of detection were determined to 10⁻⁴ to 10⁻¹ M and 5.8 × 10⁻⁵ M, respectively. The sensor also demonstrates selectivity to representative interfering ions, with log K_ij of −2.39 ± 0.12 (Na⁺), −2.86 ± 0.09 (Li⁺), −3.06 ± 0.09 (Ca²⁺), −2.74 ± 0.12 (Mg²⁺) and −0.95 ± 0.08 (NH₄⁺). By eliminating the ISM layer, the water-layer effect is effectively avoided, resulting in excellent long-term stability with a potential drift of 57.2 ± 6.1 μV h⁻¹ over 7 days. The sensor was further applied to the analysis of K⁺ in real lake water samples, where the measured concentration showed good agreement with ion chromatography results. This work provides an ISM-free SC-ISE strategy for ion analysis in water environments. Full article

AQP8-type water channels are expressed superficially in the plasma membrane or intracellularly in the inner mitochondrial membrane, where they respectively function in osmohomeostasis or as peroxiporins to alleviate oxidative stress. To date only single-copy AQP8 or AQP16 genes are known in tetrapods and two binary gene clusters composed of aqp8aa-aqp8ab and aqp8ba-aqp8bb in teleost fishes. Here, using phylogenomic and synteny analyses, we revise this view and show that bony fish aqp8aa, -ab, -ba and -bb genes are non-canonical co-orthologs that independently arose at chromosomal breakpoints. Conversely, canonical orthologs of tetrapod AQP8 are now detected in all vertebrate classes except hagfishes. In cartilaginous fishes, intact aqp8 orthologs and linked pseudogenes exist in squalomorph sharks and only fractionated aqp8-like pseudogenes in galeomorph sharks. Some isolated aqp8-like exons are detected in batoid ray genomes, while no aqp8-type coding sequences are currently found in holocephalan genomes. In the actinopterygian (ray-finned fish) lineage, the canonical ortholog of tetrapod AQP8 is estimated to have undergone gene translocation in their common ancestor ~400 million years ago but was subsequently inactivated or lost in many descendant lineages. In close temporal proximity to this gene translocation event, the actinopterygian aqp8aa-aqp8ab binary gene cluster was generated in the original syntenic locus, potentially as a result of meiotic recombination. Our data support a model of total chromosomal replication for the generation of AQP16 genes and the teleost aqp8ba-aqp8bb gene cluster. We further uncover additional duplicates in Strepsirrhini primates that provide an eminent example of the stochastic nature of neofunctionalization. The present data thus suggest that that common ancestral genome duplications combined with lineage-level chromosomal translocation, recombination and replication events contributed to the diversification of vertebrate AQP8-type genes. Full article

The cornea of the dromedary camel is essential for maintaining ocular clarity and protecting the eye in dry, dusty, and thermally stressful environments. Aquaporins are membrane channels that facilitate water transport, and AQP1 has been widely implicated in corneal fluid homeostasis in several species. The present work investigated, for the first time, the regional distribution of AQP1 in the camel cornea. Corneas collected from twelve healthy adult camels after slaughter were divided into nine anatomical regions: central (C), middle dorsal (MD), middle ventral (MV), middle nasal (MN), middle temporal (MT), peripheral dorsal (PD), peripheral ventral (PV), peripheral nasal (PN), and peripheral temporal (PT). Histological examination and immunohistochemistry were combined with digital morphometry to assess corneal layer thickness and AQP1 localization. AQP1 labeling was identified in the corneal epithelium, stromal keratocytes, and endothelium. Epithelial staining differed among regions and was most pronounced in the peripheral nasal region, whereas stromal keratocytes and endothelial cells showed strong and relatively uniform immunoreactivity. These findings indicate that AQP1 is broadly expressed in the camel cornea and likely contributes to regional control of hydration and tissue maintenance in an arid-adapted species. Full article

The coexistence of emulsified oil, dissolved organics, and heavy metal ions in industrial oily wastewater makes one-step treatment highly challenging. Herein, an organic-inorganic co-modified PVDF composite membrane (MTSP) was fabricated via nonsolvent-induced phase separation, with tea polyphenols, SiO₂, and fibrous MXene synergistically incorporated. The resulting membrane exhibited a superhydrophilic/underwater oleophobic surface, with a water contact angle of 1° and an underwater oil contact angle of ~136°, owing to the optimized surface chemistry and hierarchical pore structure. As a result, the MTSP membrane effectively suppressed oil fouling while enabling rapid water transport. At 0.1 bar, the optimized membrane delivered an oil/water separation efficiency of ~99.5% and a high flux of 2420–2670 L·m⁻²·h⁻¹, while maintaining >99% separation efficiency for various emulsified oils, including kerosene, edible oil, n-hexane, and 1,2-dichloroethane. It also showed excellent recyclability and chemical stability, retaining >98–99% efficiency after five cycles and after 24 h exposure to pH 1 and pH 12 conditions. Notably, for complex simulated wastewater containing emulsified kerosene, phenol, and Fe³⁺, Cu²⁺, Zn²⁺, and Cd²⁺, the membrane maintained ~99% oil/water separation efficiency and simultaneously removed ~79% of phenol and 70–86% of heavy metal ions in a single filtration process. The superior performance is attributed to the synergistic effects of the superhydrophilic/underwater-oleophobic membrane surface, hierarchical transport channels enabling rapid water permeation, and multifunctional sites that adsorb/coordinate dissolved pollutants. This work provides a simple, scalable design strategy for PVDF-based membranes that integrate high-flux separation, antifouling performance, and multi-pollutant remediation for the treatment of complex oily wastewater. Full article

Two-dimensional (2D) MXene membranes have emerged as a focal platform for ionic separations owing to their exceptional mechanical flexibility, intrinsic hydrophilicity, abundant surface terminations, and high electrical conductivity. This review summarizes recent advances in MXene-based membranes, with an emphasis on structural engineering strategies and their translation to ion-separation applications. We first outline representative fabrication routes for MXene membranes. We then discuss how separation mechanisms can be understood and deliberately tuned across four key scenarios: monovalent/monovalent ion separations, monovalent/multivalent ion separations, anion/cation separations, and heavy-metal ion separations. Finally, we highlight outstanding challenges and future opportunities, aiming to provide actionable guidance for the rational design and scalable manufacturing of high-performance MXene membranes for ionic separations. Full article

The potential of water-soluble membrane proteins (wsMPs) has not been fully realized. In this article, we exploit the nearly identical functionality of wsMPs with their membrane-bound counterparts and show that we can create water-soluble membrane proteins that incorporate into the plasma membranes of cells and alter their fate. As a proof of concept, we demonstrate the functional properties of water-soluble engineered pore-forming proteins, K⁺ ionic channels (MthK), and constitutively active GPCRs—among them frizzled receptors—both in vitro and in vivo. We call this method in vivo deployment of recombinant viable MPs, iDRIVE. Furthermore, we demonstrate that our strategy mediates the unidirectional insertion of MPs into the plasma membrane, and through constitutively active receptors, we present evidence for similar signaling pathway activation between small molecules and our water-soluble proteins using model phenotypes and molecular signaling assays. We present three examples where wsMPs are functional in dictating cellular fate, both in vitro and in vivo. Lastly, we show the induction of similar differential methylation via the activation of the Wnt signaling pathway using the conventional small molecule agonist, CHIR99021, or our wsFrizzled receptors (iDRIVE-FZD) in human embryonic kidney (HEK 293) embryoid spheroids (ESs). Additionally, we show that Wnt activation via wsFrizzled receptors results in even more biologically relevant epigenetic changes than via the small molecule CHIR99021. Future work will employ iDRIVE to differentiate stem cells in the production of research and clinically relevant organoids. Full article

Structural optimization of the cathode flow field is a viable approach to homogenize multi-physical field distributions and boost the output of air-cooled proton exchange membrane fuel cells (PEMFCs). This work develops a three-dimensional non-isothermal model to systematically evaluate the performance of graded flow channel designs. The results indicate that the graded structure promotes fluid transport in the central zone, thereby improving oxygen distribution uniformity at the gas diffusion layer/catalyst layer (GDL/CL) interface. Compared to the traditional parallel flow channel (with an average oxygen mass fraction of 0.051% and a uniformity index of 0.779), this configuration yields a 6.4% increase in the average oxygen mass fraction and a 0.96% enhancement in distribution uniformity. However, increased gradient flow reduces the flow velocity within the channels and raises the operating temperature, posing challenges for water and thermal management. The curved channel design, featuring longer channels at the ends and shorter channels in the center, compensates for the uneven air supply caused by the fan, thus balancing the flow distribution. Among the tested configurations, the 10° curved structure exhibits optimal performance, achieving the best compromise between gas distribution and liquid water removal. It effectively promotes oxygen diffusion and uniform water distribution, significantly alleviating mass transfer polarization and yielding a more uniform interface temperature distribution due to evaporative cooling. Both excessively small and large curvature angles lead to performance degradation, primarily due to inadequate water removal and flow separation, accompanied by excessive pressure drop, respectively. In contrast, the 10° curved channel strikes an optimal balance, offering significant advantages in overall cell performance and water–thermal management, which provides critical guidance for optimizing PEMFC flow field designs. Full article

Efficient energy harvesting from open-channel flows offers a sustainable solution for powering distributed sensing systems in water infrastructure. This study investigates a piezoelectric wake-excited membrane vortex-induced vibration (VIV) energy harvester through a combined numerical and mechanical approach. The device features an upstream cylindrical bluff body that generates a periodic vortex street, exciting a downstream flexible membrane equipped with surface-mounted piezoelectric patches. A one-way coupled CFD–FEM framework implemented in ANSYS was employed to assess the effects of membrane length, material stiffness, and flow conditions on hydrodynamic loading, structural deformation, and deformation power. Results show that membrane length mainly affects oscillation amplitude and force levels, whereas material stiffness has a stronger influence on membrane deformation and RMS mechanical power. Among the investigated materials, low-stiffness polyethylene yields the highest deformation power, while none of the analysed configurations reaches a full lock-in condition within the explored parameter range. Complementary mechanical analysis revealed that the stiffness of commercial piezoelectric patches significantly reduces local strain, thereby constraining the practically harvestable energy in the present baseline configuration. Spectral power density analysis identified the dominant shedding frequency and its harmonics, confirming that the flow response is governed by a coherent periodic excitation. These findings highlight key design trade-offs in wake-excited membrane harvesters and provide useful guidance for the future optimisation of self-powered hydraulic monitoring systems. Full article

This work presents a novel, membrane-inspired hybrid framework composed of Ag₂Mo₃O₁₀·1.8H₂O nanowires grown in situ on carbon fiber cloth (CFC) for the continuous and selective recovery of high-value sulfur-containing molecules from organic wastewater. The framework forms an integrated hierarchical porous network rich in micro-/nano-channels, which facilitates efficient, capillary-driven water transport. Owing to its mesoporous texture and specific Ag–S coordination affinity, the material shows exceptional selectivity toward sulfur-containing dyes, enabling rapid adsorption (>94% removal of methylene blue within 10 min) and high specificity in mixed solutions. The hybrid also exhibits excellent reusability, maintaining high recovery efficiency over repeated adsorption–desorption cycles. When configured into a continuous-flow system, the framework operates without external pressure and achieves a water transport rate of 1875 mL·h⁻¹·m⁻². These findings underscore the potential of the Ag₂Mo₃O₁₀·1.8H₂O/CFC hybrid as an efficient, scalable, and sustainable platform for resource-oriented wastewater treatment. Full article

Phytochemicals, including flavonoids, stilbenoids, alkaloids, terpenoids, and structurally related synthetic small molecules, exhibit a broad spectrum of beneficial pharmacological effects. These effects stem not only from interactions with specific protein targets but also from their capacity to modify the physical properties of biological membranes. A key membrane property influenced by these plant-derived compounds is the electrical potential drop at the membrane–water interface, which plays a crucial role in numerous cellular processes. Changes in membrane potential impact the function of embedded proteins and ion channels, thereby modulating cell signaling, transport, and pharmacological responses. This review compiles data on how diverse plant and synthetic small molecules alter membrane physical characteristics, particularly the dipole component of the boundary potential in lipid bilayers primarily composed of phosphatidylcholine, a predominant membrane lipid in mammals and fungi. In-depth analysis of structure–activity relationships in this context elucidates how various structural modifications affect the compounds’ ability to shift membrane electrical potential. Understanding these relationships can pinpoint molecular features that drive membrane interactions and facilitate the discovery and design of more potent dipole-modifying agents with therapeutic potential. Full article