Search Results (1,616)

In this work, highly water-soluble silk fibroin (SF) is first prepared by recrystallizing degummed silkworm cocoon fibers in concentrated CaCl₂ solution (replacing the conventional Ajisawa’s reagent), and then used as both stabilizing and reducing agents to synthesize copper nanoclusters (Cu@SF NCs) at pH = 11. Due to the existence of unreacted Cu²⁺ ions, the resulting SF-templated Cu NCs form slight aggregates, yielding a purple-colored solution with blue fluorescence. Interestingly, upon adding the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D), the Cu NCs aggregates disassemble and the fluorescence is significantly enhanced, creating a “fluorescence-on” sensor for 2,4-D with a detection limit of 0.65 μM. In contrast, the pollutant p-nitrophenol (p-NP) quenches the fluorescence of Cu NCs via a fluorescence resonance energy transfer mechanism (with a detection limit as low as 1.35 nM), which is attributed to the large overlap between absorption spectrum of p-NP and excitation spectrum of Cu NCs. Other tested analytes (i.e., pyrifenox, carbofuran and melamine) produce negligible fluorescence changes. The distinct sensing mechanisms are elucidated with experimental evidence and density functional theory (DFT) calculations. The evolutions of fluorescence as a function of incubation time and analyte concentration are systematically investigated, demonstrating a versatile platform for sensitive and selective detection of target analytes. These findings provide an effective strategy for optimizing the optical properties of metal nanoclusters and improving their performance in environmental applications. Full article

Sustained abiotic stress severely impairs fruit crop growth and development. As plants’ primary environmental sensing organ, fruit tree roots experience disrupted morphogenesis and physiological functions, reducing yield, lowering fruit quality, and threatening orchard ecosystem stability. Abiotic stress is diverse: water deficit from drought, extreme temperature fluctuations, and salinization-induced ion imbalance, heavy metal accumulation, or nutrient disorders. Its complexity requires synergistic and crosstalk regulation of multiple root-specific signaling modules and pathways in root stress perception and transduction. When responding to stress, roots activate hormone, reactive oxygen species (ROS), and calcium ion (Ca²⁺) signaling. These pathways mediate early stress recognition and regulate downstream gene expression and physiological metabolic reprogramming via transcription factors (TFs) and other regulators, determining stress tolerance and adaptability. Using typical abiotic stresses as models, this review outlines the composition, activation mechanisms, specificity, and synergistic effects of root-specific signaling modules/pathways, along with modern biotechnologies for decoding these modules and current research limitations, aiming to reveal the root signal network’s integration mode. Full article

Lanthanide coordination polymers have been developed at a fast rate during the past two decades due to their appealing applications in the modern field of materials science and emerging technologies like luminescence, magnetism, sensing, gas adsorption, and catalysis. The role of lanthanides in imparting specific properties to the coordination polymers has been fully documented in extensive studies carried out by numerous research groups. It has been shown that because lanthanide(III) ions possess a variable coordination number, they readily build two-dimensional and three-dimensional architectures with definite channels, permanent pores, and distinct surface areas. Due to their strong oxophilic propensity and hard Lewis acid character, lanthanides favor the construction of stable coordination polymers and MOF configurations by strongly binding the coordinating groups of the organic linkers. Associated with palladium complexes, the lanthanide ions provide synergistic effects with Lewis acid sites, beneficial to the catalytic activity. These attractive characteristics of lanthanides enabled them to be fruitfully applied in Pd-Ln coordination polymers with catalytic properties. This review covers an array of Pd-Ln coordination polymers applied as heterogeneous catalysts in Suzuki–Miyaura C(sp²)-C(sp²) cross-coupling reactions. The activity and chemoselectivity of Pd(II) ions and Pd nanoparticles associated in coordination polymers with different lanthanides from a selected array of rare earth elements (Eu, Sm, Eu, Gd, Pr, Nd, Ce, La, or Tb) is discussed. High yields (>99%) are attained under optimized reaction conditions. The specific role of lanthanides and organic ligands in creating sustainable and recyclable heterogeneous Pd catalysts is evidenced. Mechanistic aspects of the C(sp²)-C(sp²) cross-coupling reactions are considered. The synergistic interaction between lanthanides and palladium as well as with the organic ligands is highlighted. Full article

In recent years, electrochemical pressure (ECP) sensors with self-powered and both dynamic and static pressure detection capabilities have received widespread attention. To improve pressure sensing performances while reducing the thickness of conventional sandwich structure ECP sensors, we propose an ECP sensor with a simple electrode coplanar structure. Specifically, it consists of Cu/Zn foil electrodes and LiCl/polyvinyl alcohol (PVA) modified filter paper. Among them, the Cu/Zn coplanar electrodes are used for redox reactions, the LiCl provides conductive ions, and the PVA is used to provide a humid environment to promote the ionization and conduction of LiCl. The rough surface microstructure of the filter paper is used to enhance the pressure sensing performances of the sensor. The results show that the ECP sensor with an electrode coplanar structure can spontaneously output current in the pressure range of 0.4–100 kPa, with sensitivities of 0.273 kPa⁻¹ (0.6–20 kPa) and 0.036 kPa⁻¹ (20–100 kPa). Specifically, compared to ECP sensors with a sandwich structure, it has a wider response range and higher sensitivity. Through the current response, morphological characterizations, and redox reactions, the pressure sensing mechanism is elucidated. Furthermore, the proposed ECP sensor can be used for respiratory state recognition combined with machine learning. This research provides a new approach for developing a high-performance ECP sensor with a simple electrode coplanar structure. Full article

Background/Objectives: Essential amino acids’ (EAAs) biological effects depend on both gastrointestinal stability and intestinal bioavailability. A commercially available EAA blend has previously shown to be highly bioaccessible and able to inhibit the DPP-IV enzyme both directly and at a cellular level following simulated digestion in vitro. In light with this consideration, the present study aimed to evaluate the intestinal in vitro bioavailability of GAF subjected to INFOGEST digestion (iGAF) and to investigate the metabolic effects of its bioavailable fraction on muscle cells using an integrated Caco-2/C2C12 co-culture model. Methods: Differentiated Caco-2 cell lines were treated with iGAF, and amino acid transport was quantified by ion-exchange chromatography. The basolateral fraction containing bioavailable EAAs was used to treat differentiated C2C12 myotubes for 24 h. Western blot analyses were performed to assess the activation of anabolic and metabolic pathways, including mTOR, Akt, GSK3, AMPK and GLUT-4. Results: More than 50% of each EAA present in iGAF crossed the Caco-2 monolayer, with BCAAs and phenylalanine particularly enriched in the basolateral fraction. Exposure of C2C12 myotubes to the bioavailable iGAF stimulated mTORC1 activation and increased the phosphorylation of Akt and GSK3, indicating an enhanced anabolic response. At a cellular level, iGAF also elevated the p-AMPK/AMPK ratio, suggesting activation of energy-sensing pathways. Moreover, GLUT4 protein levels and glucose uptake were significantly increased. Conclusions: The study focuses exclusively on a cellular model, and results suggested that iGAF is highly bioavailable in vitro and that its absorbed fraction activates key anabolic and metabolic pathways of skeletal muscle cells, enhancing both protein synthesis signaling and glucose utilization in vitro. Full article

Nitrite, as a widely present nitrogen oxide compound in nature, and is extensively distributed in production and daily life; precise and rapid detection of it is of great significance for ensuring human health. This study developed nitrogen-doped carbon dots (N-CDs) using malic acid and 3-diethylaminophenol as precursors by one-step hydrothermal treatment. The obtained N-CDs exhibited strong green fluorescence with a high quantum yield of 20.86%. More importantly, they served as a highly effective fluorescent probe for NO₂⁻ sensing, demonstrating a low detection limit of 28.33 μM and a wide linear response range of 400 to 1000 μM. The sensing mechanism was attributed to an electrostatic interaction-enhanced dynamic quenching process. Notably, the probe enabled dual-mode detection: a distinct color change from light pink to dark brown under daylight for visual semi-quantification, and quantitative fluorescence quenching. The N-CDs showed excellent selectivity over common interfering ions. Furthermore, their low cytotoxicity and good biocompatibility allowed for successful bioimaging of exogenous and endogenous NO₂⁻ fluctuations in live HeLa cells. This work presents a facile green strategy to synthesize multifunctional N-CDs that realized the sensitive, selective, and visual detection of NO₂⁻ in environmental and biological systems. Full article

Acid-sensing ion channels (ASICs), activated under acidic conditions, play a critical role in ischemic brain injury, but the detailed mechanisms and signaling pathways remain unclear. Our previous studies have shown that activation of ASIC1a channels contributes to acidosis-induced neuronal injury, partially mediated by increased calcium influx. In this study, we provide evidence that activation of ASIC2a-containing channels induces zinc influx. In cultured mouse cortical neurons, ASIC currents that were insensitive to PcTx1 inhibition were potentiated by extracellular zinc. In Chinese Hamster Ovary cells transfected with different ASIC subunits, large inward currents were recorded upon a pH drop from 7.4 to 5.0 in cells expressing homomeric ASIC1a, ASIC2a, or heteromeric ASIC1a/2a channels when normal Na⁺-rich extracellular fluid (ECF) was used. However, when ECF was modified to one containing zinc as the primary cation, the same pH drop induced an inward current only in cells expressing homomeric ASIC2a or heteromeric ASIC1a/2a, but not homomeric ASIC1a. Fluorescence imaging revealed rapid zinc influx in cells expressing ASIC2a but not ASIC1a when zinc was applied with the acidic ECF. Additionally, at pH values where ASIC2a-containing channels were activated, acid-mediated neurotoxicity was exacerbated by zinc. Thus, ASIC2a-containing channels may represent a novel pathway for zinc entry and activation of these channels might contribute to zinc-mediated neurotoxicity. Full article

Lithium-ion batteries (LIBs) face the safety hazard of thermal runaway (TR). Gas-sensing-based monitoring is one of the viable warning approaches for batteries during operation, and TR warning using semiconductor gas sensors has garnered widespread attention. This review presents a comprehensive analysis of the latest advances in this field. It details the gas release characteristics during the TR failure process and identifies H₂, electrolyte vapor, CO, CO₂, and CH₄ as effective TR warning markers. The core of this review lies in an in-depth critical analysis of gas-sensing materials designed for these target gases, systematically summarizing the design, performance, and application research of semiconductor gas-sensing materials for each aforementioned gas in battery monitoring. We further summarize the current challenges of this technology and provide an outlook on future development directions of gas-sensing materials, including improved selectivity, integration, and intelligent advancement. This review aims to provide a roadmap that directs the rational design of next-generation sensing materials and fast-tracks the implementation of gas-sensing technology for enhanced battery safety. Full article

Zinc (Zn), a ubiquitous environmental transition metal primarily existing as Zinc ions (Zn²⁺), plays a critical role in various biological processes. Its extensive application in agriculture, industry, and healthcare has led to significant environmental contamination. However, the mechanistic contribution of Zn²⁺ to bacterial antibiotic resistance and virulence remains insufficiently understood. This review explores the sources, cycling, and environmental accumulation of Zn²⁺ in a One Health context, emphasizing their impact on bacterial antibiotic resistance and virulence. Zn²⁺ promote bacterial antibiotic resistance by regulating efflux pumps, biofilm formation, expression and transfer of antibiotic resistance genes, as well as synergistic effects with other heavy metals and antibiotics. Meanwhile, Zn²⁺ promote bacterial virulence by regulating quorum sensing, secretion and metal homeostasis systems, as well as oxidative stress response and virulence factor expression. Additionally, it highlights the potential of targeting Zn homeostasis as a strategy to combat environmental antibiotic resistance. Collectively, these findings provide key insights into the mechanisms by which Zn²⁺ regulate bacterial antibiotic resistance and pathogenicity, offering valuable guidance for developing strategies to mitigate the global threat of antibiotic resistance. Full article

We report a defect-selective luminescence response in calcium-deficient hydroxyapatite (HAp) induced by electron and ion irradiation. Compacted HAp pellets prepared from hydrothermally grown nanofibers were investigated to analyze defect-related luminescence using photoluminescence (PL) and cathodoluminescence (CL) techniques, both before and after compaction. Low-energy electron beam irradiation (15 keV) produced a two-stage luminescent response, an initial enhancement arising from field-assisted activation of OH-channel vacancies (V_OH and V_OH + H_i), followed by an exponential decay attributed to defect annealing. Monochromatic transient CL measurements show that this rise–decay behavior is selective to the OH-related bands at 2.57 and 2.95 eV, whereas the 3.32 and 3.67 eV emissions exhibit only a monotonic exponential decay. The corresponding decay constants further indicate that the activated OH-channel vacancies anneal more rapidly than the other centers, consistent with their higher electron-capture probability and lower structural stability. In contrast, ${\mathrm{Ga}}^{+}$ ion irradiation (30 keV, 1.4 × 10⁻¹³ A/µm²) induced progressive monotonic luminescence quenching, primarily driven by selective annealing of oxygen vacancies in $\mathrm{P}{\mathrm{O}}_4^{3-}$ groups. These complementary pathways, electron-induced activation and ion-driven suppression, demonstrate that irradiation serves as a versatile tool for defect engineering in hydroxyapatite. Beyond providing fundamental insights into vacancy stability, these results open new routes for tailoring the optical, sensing, and bioimaging functionalities of HAp through controlled irradiation. Full article

The field of electrochemical devices, encompassing energy storage, fuel cells, electrolysis, and sensing, is fundamentally reliant on the electrode materials that govern their performance, efficiency, and sustainability. Traditional materials, while foundational, often face limitations such as restricted reaction kinetics, structural deterioration, and dependence on costly or scarce elements, driving the need for continuous innovation. Emerging electrode materials are designed to overcome these challenges by delivering enhanced reaction activity, superior mechanical robustness, accelerated ion diffusion kinetics, and improved economic feasibility. In energy storage, for example, the shift from conventional graphite in lithium-ion batteries has led to the exploration of silicon-based anodes, offering a theoretical capacity more than tenfold higher despite the challenge of massive volume expansion, which is being mitigated through nanostructuring and carbon composites. Simultaneously, the rise of sodium-ion batteries, appealing due to sodium’s abundance, necessitates materials like hard carbon for the anode, as sodium’s larger ionic radius prevents efficient intercalation into graphite. In electrocatalysis, the high cost of platinum in fuel cells is being addressed by developing Platinum-Group-Metal-free (PGM-free) catalysts like metal–nitrogen–carbon (M-N-C) materials for the oxygen reduction reaction (ORR). Similarly, for the oxygen evolution reaction (OER) in water electrolysis, cost-effective alternatives such as nickel–iron hydroxides are replacing iridium and ruthenium oxides in alkaline environments. Furthermore, advancements in materials architecture, such as MXenes—two-dimensional transition metal carbides with metallic conductivity and high volumetric capacitance—and Single-Atom Catalysts (SACs)—which maximize metal utilization—are paving the way for significantly improved supercapacitor and catalytic performance. While significant progress has been made, challenges related to fundamental understanding, long-term stability, and the scalability of lab-based synthesis methods remain paramount for widespread commercial deployment. The future trajectory involves rational design leveraging advanced characterization, computational modeling, and machine learning to achieve holistic, system-level optimization for sustainable, next-generation electrochemical devices. Full article

Calcium ions (Ca²⁺) serve as universal second messengers regulating endocrine, neuronal, and metabolic processes. In children and adolescents, tight calcium signaling control is crucial for growth, hormone homeostasis, neuromuscular function, and neurodevelopment. Disruptions in Ca²⁺-dependent pathways—whether genetic, metabolic, or acquired—underlie a spectrum of pediatric endocrine diseases often presenting with neurological manifestations This review summarizes calcium’s roles in hormone secretion, parathyroid and vitamin D metabolism, and neuronal excitability, and discusses monogenic and metabolic disorders affecting calcium sensing and signaling, including CASR, GNA11, AP2S1, STIM1, and ORAI1 mutations. Diagnostic challenges, therapeutic strategies, and future directions for precision medicine in pediatric neuroendocrinology are highlighted, emphasizing early recognition and improved clinical outcomes. Full article

Transition metal (TM)-doped zinc oxide (ZnO) and zirconium dioxide (ZrO₂) nanocrystals exhibit complex correlations between crystal structure, defect chemistry, vibrational properties, and magnetic behavior that are strongly governed by synthesis route and dopant incorporation mechanisms. This review critically summarizes recent progress on Fe-, Mn-, and Co-doped ZnO and ZrO₂ nanocrystals synthesized by wet chemical, hydrothermal, and microwave-assisted hydrothermal methods, with emphasis on synthesis-driven phase evolution and apparent solubility limits. ZnO and ZrO₂ are treated as complementary host lattices: ZnO is a semiconducting, piezoelectric oxide with narrow solubility limits for most 3d dopants, while ZrO₂ is a dielectric, polymorphic oxide in which transition metal doping may stabilize tetragonal or cubic phases. Structural and microstructural studies using X-ray diffraction, electron microscopy, Raman spectroscopy, and Mössbauer spectroscopy demonstrate that at low dopant concentrations, TM ions may be partially incorporated into the host lattice, giving rise to diluted or defect-mediated magnetic behavior. When solubility limits are exceeded, nanoscopic secondary oxide phases emerge, leading to superparamagnetic, ferrimagnetic, or spin-glass-like responses. Magnetic measurements, including DC magnetization and AC susceptibility, reveal a continuous evolution from paramagnetism in lightly doped samples to dynamic magnetic states characteristic of nanoscale magnetic entities. Vibrational spectroscopy highlights phonon confinement, surface optical phonons, and disorder-activated modes that sensitively reflect nanocrystal size, lattice strain, and defect populations, and often correlate with magnetic dynamics. Rather than classifying these materials as diluted magnetic semiconductors, this review adopts a synthesis-driven and correlation-based framework that links dopant incorporation, local structural disorder, vibrational fingerprints, and magnetic response. By emphasizing multi-technique characterization strategies required to distinguish intrinsic from extrinsic magnetic contributions, this review provides practical guidelines for interpreting magnetism in TM-doped oxide nanocrystals and outlines implications for applications in photocatalysis, sensing, biomedicine, and electromagnetic interference (EMI) shielding. Full article

Magnesium (Mg²⁺) ions require sensitive and selective detection due to their low concentrations and coexistence with similar ions in matrices. This study developed a potentiometric ISE using a new modified polyurethane membrane. The membrane’s negative surface charge facilitates selective interaction with Mg²⁺ ion. Optimal performance was obtained at 0.0061% (w/w) κ-carrageenan and 0.0006% (w/w) D2EHPA. The ISE exhibited a near-Nernstian response of 29.49 ± 0.01 mV/decade across a 10⁻⁹–10⁻⁴ M concentration range (R² = 0.992), with a detection limit of 1.25 × 10⁻¹⁰ M and a response time of 200 s. It remained stable in the pH range 6–8 for one month and demonstrated high selectivity over K⁺, Na⁺, and Ca²⁺ ($K_{ij}$ < 1). The repeatability and reproducibility tests yielded standard deviations of 0.15 and 0.39, while recovery rates confirmed analytical reliability. The water contact angle analysis showed a reduction from ~80° to ~69° after membrane conditioning, indicating increased hydrophilicity and improved interfacial for ion diffusion. FTIR analysis confirmed successful modification by reduced O–H peak intensity, while XRD verified the amorphous structure. SEM revealed a dense top layer with concave morphology, favorable for minimizing leakage and ensuring efficient ion transport within the sensing system. Full article

Osteoarthritis (OA) is a multifactorial degenerative joint disease in which aberrant mechanical cues act in concert with metabolic dysregulation and chronic low-grade inflammation, with chondrocyte hypertrophy representing a key pathological event driving cartilage degeneration. Alterations in extracellular matrix (ECM) properties—including mechanical loading, stiffness and viscoelasticity, topological organization, and surface chemistry—regulate hypertrophic differentiation and matrix degradation in a zone-, stage-, and scale-dependent manner. Microscale measurements often reveal localized stiffening in superficial zones during early OA, whereas bulk tissue testing can show softening or heterogeneous changes in deeper zones or advanced stages, highlighting the context-dependent nature of ECM mechanics. These biophysical signals are sensed by integrin-based adhesion complexes, primary cilia, mechanosensitive ion channels (TRP/Piezo), and the actin cytoskeleton–nucleus continuum, and are transduced into intracellular pathways with zone- and stage-specific effects, governing chondrocyte fate under physiological and osteoarthritic conditions. Mechanism-based anti-hypertrophic strategies include biomimetic scaffold design for focal defects, dynamic mechanical stimulation targeting early OA, and multimodal approaches integrating mechanical cues with biochemical factors, gene modulation, drug delivery, or cell-based therapies. Collectively, this review provides an integrated mechanobiological framework for understanding cartilage degeneration and highlights emerging opportunities for disease-modifying interventions targeting chondrocyte hypertrophy. Full article