Search Results (843)

Rapid urbanization and inadequate sanitation infrastructure threaten water security in many sub-Saharan African cities. This study aimed to provide an integrated assessment of groundwater, surface water, and wastewater quality in Bangui by characterizing physicochemical parameters, trace metals, and microbiological indicators, and by identifying potential contamination sources and pathways among these water compartments. A total of 28 water samples were collected from groundwater, surface water, and wastewater sites. Physicochemical parameters, major ions, trace metals, and microbiological indicators were analyzed using standardized methods, including ion chromatography, ICP-OES, ICP-MS, and membrane filtration. Results revealed a clear contamination gradient. Wastewater showed the highest electrical conductivity, turbidity, chloride concentrations, and microbial loads, reaching 2.41 × 10⁶ CFU/100 mL for total coliforms and 1.93 × 10⁶ CFU/100 mL for fecal coliforms. Groundwater exhibited high nitrite levels and low dissolved oxygen, indicating vulnerability to sewage infiltration. Surface waters were characterized by high turbidity and widespread fecal contamination despite relatively good oxygenation. In contrast, trace metal concentrations generally remained below World Health Organization guideline values. Geochemical analyses identified distinct elemental signatures for each water type. Microbiological contamination emerged as the dominant water quality concern. High fecal coliform/fecal streptococci ratios (13.08-22.16) indicated predominantly human-derived pollution linked to untreated wastewater and inadequate sanitation systems. The association between elevated nitrite concentrations and fecal indicators suggests active contamination pathways connecting wastewater, surface water, and shallow aquifers. These findings highlight the urgent need for improved wastewater management, groundwater protection, and long-term monitoring to ensure sustainable urban water security in Bangui. Full article

Self-assembled liquid crystal polymer networks build directional transport channels via molecular alignment, enabling efficient and ordered lithium-ion migration, while single-ion conducting polymer electrolytes improve lithium-ion transference number by covalently anchoring anions, which alleviates concentration polarization and effectively suppresses lithium dendrite growth. Herein, a series of substrate-free Li salt-grafted cholesteric liquid crystal elastomers (CLCE) with tunable helical pitches and spiral orientation were fabricated, and quasi-solid electrolyte membranes were obtained through plasticization. It was found that samples with the smallest helical pitch delivered the highest lithium-ion transference number irrespective of the spiral orientation. The optimal CLCE electrolyte membrane achieved a lithium-ion transference number of 0.94, exhibiting characteristic single-ion conductivity. Moreover, after adding small amount of extra free Li salt, the prepared electrolyte membrane delivered a room-temperature ionic conductivity of 2.6 × 10⁻⁴ S·cm⁻¹, an electrochemical stability window of 5.2 V and stable cycling performance, providing new insights into the design of high-performance safe quasi-solid lithium-ion batteries. Full article

Aspergillus westerdijkiae, a filamentous fungus commonly isolated from pickled vegetables and high-salt condiments, can cause spoilage and produce nephrotoxic ochratoxin A (OTA) under saline conditions. However, its adaptive mechanisms to salt stress remain unclear. To address this, the pickle-derived strain NDX1 was subjected to 0, 1.0, 1.5, and 2.0 mol/L NaCl treatments. Colony growth was assessed after 7 days of incubation on PDA plates supplemented with the respective NaCl concentrations. For physiological indices, mycelia were pre-cultured in salt-free PDB for 5 days, followed by the addition of NaCl to final concentrations (0, 1.0, 1.5, and 2.0 mol/L) and further incubation for 2 days, after which relative electrical conductivity (REC) and malondialdehyde (MDA) content were measured. Colony diameters were recorded to evaluate vegetative growth; REC was determined by conductometry to assess cell membrane permeability; and MDA content was measured via the thiobarbituric acid (TBA) colorimetric method to indicate lipid peroxidation levels. Transcriptome sequencing combined with qRT-PCR validation was employed to identify differentially expressed genes (DEGs) involved in osmotic adaptation. Results showed that low salinity (1.0 mol/L NaCl) promoted growth, while higher concentrations (≥1.5 mol/L NaCl) inhibited it, accompanied by increased REC and decreased MDA, forming a distinctive high-permeability, low-lipid-peroxidation phenotype. A total of 3155 DEGs were detected, mainly associated with the HOG-MAPK cascade, glycerol biosynthesis, and ion transport pathways. Eight key HOG-MAPK genes and 21 glycerol metabolic genes were upregulated in a concentration-dependent manner, with the terminal kinase Hog1 coordinating transcription of downstream effectors governing glycerol synthesis and ion homeostasis. These findings demonstrate that A. westerdijkiae integrates de novo glycerol production and intracellular lipid remodeling via the HOG-MAPK pathway to achieve osmotic adaptation under hypersaline stress. This work identifies potential molecular targets for controlling toxigenic spoilage caused by this species in high-salt fermented foods. Full article

Methane aromatization mainly proceeds at 650–750 °C. Simultaneous separation of hydrogen and oxygen can boost conversion efficiency and mitigate catalyst coking, yet most non-electrochemical membrane reactors fail to achieve synchronous hydrogen–oxygen separation within this temperature range. Accordingly, an electrochemical membrane reactor is adopted in this work, and steam is introduced to improve gas separation efficiency. BZCY hollow fiber membranes with mixed proton and oxygen ion conductivity are selected as the research material, and the influences of three distinct steam feeding modes (anode side only, cathode side only, simultaneous feeding on both sides) on H₂ and O₂ permeation and separation are systematically investigated. Experimental results reveal that steam humidification significantly enhances the permeation fluxes of hydrogen and oxygen. Notably, such promotional effect strongly depends on the steam feeding location. At 700 °C and 1.5 V, the hydrogen permeation flux increases to 1.469 mL⋅min⁻¹⋅cm⁻², in sharp contrast to 0.189 mL⋅min⁻¹⋅cm⁻² under dry atmosphere. Meanwhile, the oxygen permeation flux reaches 0.824 mL⋅min⁻¹⋅cm⁻² at 700 °C with steam, which is approximately four times that under dry conditions. This study verifies the intrinsic H₂ and O₂ permeation capability of electrochemical membrane reactors and the remarkable promotion effect originating from steam, facilitating further practical applications of such membrane reactors in methane aromatization. Full article

To survive, cells are able to adapt to a wide range of adverse conditions, such as varying pH from optimal (~7.4). They do this through mechanisms including acid-sensing ion channels, which alter cytosolic ion content and thus the cell’s electrophysiological profile. However, the impact of this adaptation on cellular electrophysiology remains unexplored. We investigated the effects of culture at a range of extracellular pH on the electrophysiological features of breast cancer cell lines MDA-MB-231 and MCF-7. Cells were subject to an acid–neutral–base pH from 3.0 to 9.2, after which their membrane potential (V_m), cytoplasm conductivity σ_cyto, effective membrane conductance G_eff, and ζ-potential were measured. Cells were also analyzed after permeabilization, to examine whether observed changes were due to cell surface chemistry, or to V_m. Both cell lines exhibited different electrophysiological phenotypes in acidic environments (pH < 6.7); MDA-MB-231 exhibited statistically significant differences in ζ-potential, V_m, G_eff and σ_cyto; MCF-7 only exhibited significant differences in σ_cyto. These findings suggest cells adapt to acidic microenvironments by altering V_m and potentially ζ-potential, reducing the extracellular potential, and hence potentially lowering proton concentration at the extracellular membrane surface. This offers new insights into potential therapeutic avenues to target the pH-dependent adaptations of cancer cells. Full article

Voltage-sensitive ion channels are glycoprotein macromolecules that carry ion currents across membranes of nerve and muscle fibers. The hypothesis presented helps explain the changes that convert an insulating ion channel into an ion conductor, stating that it undergoes a structural transformation on threshold reduction in the voltage across the membrane. Experimental data show that the excitable membrane is a ferroelectric liquid crystal. The Channel Activation by Electrostatic Repulsion hypothesis proposes the following: electrical attractions between boundary surface charges compress the polar channel into a compact smectic phase with induced dipoles. Critical depolarization eliminates surface charges and dipoles, decreasing the dielectric permittivity of the ion channel. This increases the repulsive electrostatic forces between positively charged residues in the four S4 segments. These forces form a selectivity filter dome and cause a proteinquake to a chiral nematic phase. The selectivity filter allows ions to enter as it strips their hydration waters. The permeant ions occupy hydrogen bonds of ion-conducting helices, displacing protons. Disordered regions between adjacent helices form liquid line defects. In the thermal chaos of physiological temperature, a line defect occasionally connects the inner and outer surfaces, forming a transient ion pathway that carries unpredictable surges of permeant ion currents, as observed in experiments. Tests for this hypothesis are proposed. Full article

Chloride-induced corrosion is a major threat to excavated bronze artifacts, yet conventional alkaline desalination requires repeated solution replacement and generates secondary chemical waste. Herein, a series of BiOCl-loaded carbon nanofiber composites (CNFs@BiOCl-X) were prepared by KOH activation followed by hydrothermal growth of BiOCl, aiming to develop regenerable electrodes for chloride removal in capacitive deionization systems. Alkali activation regulated the surface roughness, oxygen-containing functional groups, hydrophilicity, and BiOCl loading of CNFs, while the three-dimensional conductive network helped immobilize BiOCl nanostructures and buffer the volume variation associated with reversible Bi/BiOCl conversion. Electrochemical analyses confirmed the pseudocapacitive chloride-storage behavior of the composites, with ion removal governed by the coupled effects of BiOCl redox activity, charge transfer, and interfacial ion transport. In a fixed-electrode membrane capacitive deionization system, CNFs@BiOCl-2 exhibited the best overall performance, delivering a salt adsorption capacity of 100.44 mg g⁻¹ at 1.4 V and retaining 93.17% of its desalination capacity after 35 cycles at 1.2 V. For flow-electrode capacitive deionization, the higher BiOCl-loading CNFs@BiOCl-5 showed superior utilization of active sites and achieved 94.75% NaCl removal from a 1000 mg L⁻¹ solution within 3 h, with an average desalination rate of 15.48 μg cm⁻² min⁻¹ and an energy consumption of 0.88 kWh kg⁻¹-NaCl. These findings demonstrate that rationally matching BiOCl loading with electrode configuration enables efficient and sustainable chloride management, offering a promising electrochemical strategy for conservation electrolytes and related desalination applications. Full article

Proton-exchange membranes are crucial for water electrolyzers and fuel cells, but their performance declines under low humidity due to dehydration. Existing reviews mainly list experimental results without analyzing the mechanisms of proton conductivity stabilization. This review systematically summarizes approaches to enhance moisture-independent proton conductivity and evaluates their prospects. Key factors governing conductivity include microstructure, sulfonic group concentration, and hydration level. Stability under dry conditions depends on water retention and thermal resistance. Main strategies involve hybrid composite membranes, ionomer structure control via pre-treatments, and novel proton-conducting polymers. Promising directions include oriented channel structures, MOFs, and graphene-based materials. The stabilization mechanism relies on retaining water through hydrophilic additives that form stable hydrates, enabling proton transport even under harsh conditions (up to 120 °C and 50% RH, per US DOE targets). Among Nafion alternatives, sulfonated aromatic polymers and phosphoric-acid-doped polybenzimidazole demonstrate good performance at elevated temperatures (100–200 °C), though durability remains a challenge for the latter. Despite ongoing research, Nafion-based composites still offer one of the best overall balances of conductivity, stability, and processability. A significant research gap persists: long-term membrane performance is poorly studied, and many additives degrade over time or block proton transport sites due to ion exchange with metal cations. Full article

The electrical behavior of cellular membranes plays a fundamental role in neuronal communication and in many physiological processes involving excitable cells. Mathematical modeling has become an essential tool for understanding the physical mechanisms underlying membrane dynamics and the generation of action potentials. The classical Hodgkin–Huxley model represents the cornerstone of conductance-based descriptions of neuronal activity, providing a quantitative framework in which ionic currents across the membrane are represented through nonlinear differential equations. Over the years, numerous extensions of this model have been developed in order to incorporate additional biophysical mechanisms, including dendritic processing, temperature dependence and electromagnetic effects. However, increasing experimental evidence has shown that neuronal activity is intrinsically stochastic due to the probabilistic nature of ion-channel gating and other microscopic processes. As a consequence, stochastic modeling approaches have been introduced to complement deterministic formulations and to capture the variability observed in real neuronal systems. In this review, we focus on a selected class of membrane models grounded in physical or biophysical principles, namely models that describe membrane dynamics through electrical analogies, conductance-based equations, stochastic channel kinetics, or memory-dependent circuit elements. These approaches can be viewed as extensions, reformulations, or generalizations of the Hodgkin–Huxley framework, developed to address specific physiological or computational limitations. The review focuses on the physical and mathematical structure of selected HH-derived models rather than on their experimental validation, and aims to compare representative physically motivated modeling strategies in terms of their assumptions, interpretability, and domains of applicability. Full article

Background: Brazilian wasp venoms represent a clinically relevant yet underexplored source of bioactive molecules with important implications for allergy, toxicology, and neuropharmacology. This review discusses the biological and immunological activities of venoms from Neotropical wasp species prevalent in Brazil, particularly within the genera Polybia, Synoeca, Polistes, and Agelaia, with emphasis on venom composition, IgE-mediated hypersensitivity, and ion-channel modulation. Methods: A narrative literature review was conducted using studies focused on venom characterization, electrophysiological effects, immune responses, and clinical manifestations associated with Brazilian and other Hymenoptera species. Results: Brazilian wasp venoms contain a diverse repertoire of peptides, enzymes, and low-molecular-weight compounds that act synergistically on multiple cellular targets. Among these, mastoparan-like peptides exhibit antimicrobial, immunomodulatory, and membrane-disruptive activities, contributing to inflammation and cellular dysfunction. In addition, several venom components interact with ion channels and neuronal receptors, modulating neuronal excitability and synaptic signaling, which highlights their potential applications in neuropharmacology. Simultaneously, allergenic proteins can induce IgE sensitization and immediate hypersensitivity reactions ranging from localized manifestations to systemic anaphylaxis. The marked taxonomic and biochemical diversity of Brazilian wasps contributes to substantial variability in venom composition and clinical outcomes. Conclusions: Overall, these venoms constitute a valuable and still insufficiently explored source of biologically active compounds with potential applications in allergy diagnosis, venom immunotherapy, and drug development. Full article

PFAS form a class of synthetic chemicals that has become an area of increasing concern because of its impact on the environment and the threat it poses to human health. The structure of PFAS makes them highly resistant to degradation. As a result, they are highly effective at bioaccumulation. Certain water treatment technologies have been proven to remove PFAS from contaminated water sources. This study reviews the most promising treatment technologies used for the treatment of PFAS-contaminated waters. Well-established treatment technologies, such as granular activated carbon, ion exchange resin, reverse osmosis, and nanofiltration, were quantitatively compared. The removal efficiency was assessed by collecting the data of individual PFAS species from the literature and grouping them into five groups: PFAS (all species), PFSA, PFCA, long chain, and short chain. The results identified that, for all PFAS groups, the most effective treatment technologies were in the following order: reverse osmosis, nanofiltration, ion exchange resin, and granular activated carbon. The performance of reverse osmosis and nanofiltration did not appear to significantly differ between the different PFAS groups, as opposed to ion exchange resin and granular activated carbon, where there was a greater degree of variation in performance between different PFAS groups. Overall, it was identified that membrane technologies outperformed adsorbent technologies. However, the cost associated with membrane technologies may limit its economic viability when compared with adsorbent technologies, which are typically a more viable option except under specific circumstances. For example, contaminated water with high concentrations of other contaminants that need to be treated simultaneously. Lack of standardised experimental and operational conditions limited the available data. While this work provides guidance on which treatment is more likely to be appropriate based on the concentration and composition of different species of PFAS, more data are needed to conduct a more accurate statistical analysis and enable accurate modelling of treatment performance. Full article

The longissimus dorsi (LD) and biceps femoris (BF) muscles are important meat-producing regions in camels. Investigating differences in meat quality and proteomic profiles between the LD and BF muscles in Junggar Bactrian camels can provide a molecular basis for regulating camel meat quality and genetic improvement. In this study, 20 healthy adult male Junggar Bactrian camels were selected. Following slaughter, muscle samples were collected from the splenius (SP), triceps brachii (TB), LD, external oblique (EO), gluteus medius (GM), and BF. Meat quality parameters (pH, meat color, shear force, drip loss, and cooking loss) were measured. The LD exhibited the highest meat quality among the six cuts, in contrast to the BF, which showed the lowest. Proteomic analysis of LD and BF from 6 Junggar Bactrian camels was conducted to identify proteins associated with meat quality, yielding 81 differentially expressed proteins (DEPs). Gene Ontology (GO) enrichment analysis highlighted several significantly enriched terms among the DEPs (p < 0.05), including calcium-dependent phospholipid binding, zinc ion binding, and metal ion binding. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis (p < 0.05) further indicated notable enrichment in cytoskeletal organization, 2-oxocarboxylate metabolism, and the citric acid cycle. DEPs associated with meat quality were identified, including tubulin α-chain-like 3 and synaptic function regulator FMR1 isoform X15, which can serve as candidate DEPs for shear force. Protein phosphatase 1 regulatory subunit 14C isoform X1 can serve as a candidate differentially expressed protein for pH. Protein phosphatase 1 regulatory subunit 14C isoform X and anchoring protein repeat domain 1 can serve as candidate DEPs for cooking loss. Membrane-associated protein A4 and membrane-associated protein A7 isoform X1, as well as the transcriptional activator of cytochrome c oxidase 1, can serve as candidate DEPs for color a*. These data may serve as a reference for further studies on how different cuts affect meat quality and for practical efforts to improve camel meat quality. Full article

The development of low-cost, environmentally friendly, and electrochemically stable electrode materials remains a significant challenge for supercapacitors. In the present study, composite materials based on a montmorillonite K10 clay support were synthesized and characterized. Coconut shell-derived activated carbon, manganese dioxide (MnO₂), and/or activated carbon (YP-80F) modified with silver nanoparticles were utilized as functional additives to the clay matrix. The aim of this work is to enhance the specific capacitance and electrochemical stability of the materials through a synergistic effect between these individual components. The novelty of this study lies in the integration of montmorillonite K10-based nanocomposites with an ion-exchange hydrogel membrane and in the investigation of the synergistic effects of different functional additives on the electrochemical performance of supercapacitors. The electrodes were fabricated using a casting method, while a commercial membrane, pre-soaked in a sodium sulfate solution, was employed as both separator and electrolyte. The membrane functions as an ion-exchange hydrogel, contributing to high ionic conductivity and reduced interfacial resistance. The electrochemical results indicate that the presence of additives significantly improves electron transport within the system, while the K10 clay support acts as a stable structural framework. The obtained results demonstrate the potential of clay-based nanocomposites integrated into gel-polymer systems for the development of efficient, low-cost, and environmentally friendly next-generation supercapacitors. Full article

Silage maize (Zea mays L.) serves as a key source of high-quality roughage for ruminants, yet its production and the development of the silage maize industry in Xinjiang are severely constrained by saline–alkali stress. In this study, root growth phenotypes, root energy metabolism, cell membrane stability, osmotic regulatory substances, and reactive oxygen species (ROS) metabolism were examined to elucidate the mechanisms by which iron chlorin e6 (ICe6) enhances saline–alkali tolerance in maize roots. The results showed that saline–alkali stress significantly suppressed root growth in maize seedlings, leading to increased malondialdehyde (MDA) content and relative conductivity. This suggests that membrane lipid peroxidation has intensified, resulting in increased cell membrane permeability. Meanwhile, ICe6 enhanced antioxidant enzyme (SOD, POD, CAT, and APX) activities, scavenged H₂O₂ accumulation, reduced MDA content, and stabilized cell membrane integrity, as indicated by reduced ion leakage. Moreover, ICe6 optimized root respiratory pathways, improved root vigor, and ATP synthesis to provide adequate energy for growth, while decreasing free proline accumulation to maintain cellular osmotic balance. These findings demonstrate that ICe6 mitigates saline–alkali stress in silage maize roots through coordinated regulation of energy metabolism, antioxidant defense, and osmotic adjustment. Full article

Voltage-gated ion channels (VGICs) are traditionally associated with electrically excitable cells; however, increasing evidence indicates that they are also expressed in non-excitable cells, including vascular endothelial cells. This review aims to summarize the current knowledge on the expression, regulation, and functional role of VGICs in the vascular endothelium, and to highlight their potential contribution to endothelial signaling. We examined the molecular structure, biophysical properties, and functional roles of voltage-gated Na⁺ (Na_V), Ca²⁺ (Ca_V), and K⁺ (K_V) channels in vascular endothelial cells. Particular attention was given to studies investigating VGIC activity in native endothelium and to emerging mechanisms regulating their activation. Endothelial cells express multiple VGIC subtypes at low densities, which are insufficient to generate action potentials but can modulate membrane potential (V_M) and Ca²⁺-dependent signaling. The dynamic regulation of the endothelial V_M, through the interplay between hyperpolarizing and depolarizing conductances, emerges as a key determinant of VGIC availability and activation. VGICs contribute to essential endothelial functions, including angiogenesis, vasomotor responses, blood–brain barrier permeability, and inflammation. Dysregulated VGIC expression and/or activity may be implicated in several pathological conditions, such as atherosclerosis, calcific aortic stenosis, and tumor vascularization. VGICs represent an unexpected but functionally relevant component of endothelial signaling. Elucidating their role in native vascular beds and disease contexts may uncover novel mechanisms of endothelial regulation and identify new therapeutic targets in cardiovascular and cancer biology. Full article