Search Results (3,271)

The rational design of multifunctional electrocatalysts requires synergistic integration of conductive scaffolds with redox-active components. Here, a hierarchical core–shell NiCo₂S₄ grown/anchored on Co₉S₈-loaded carbon nanofibers (NCS/CS/CNFs) was synthesized via an electrospinning and hydrothermal approach and systematically characterized. FESEM/TEM confirmed a core-shell nanofiber structure with a NiCo₂S₄ shell thickness of ~30–70 nm, increasing the fiber diameter to ~290 ± 30 nm, while BET analysis revealed a surface area of 24.84 m² g⁻¹ and pore volume of 0.042 cm³ g⁻¹, surpassing CS/CNFs (6.12 m² g⁻¹) and NCS (4.85 m² g⁻¹). XRD confirmed crystalline NiCo₂S₄ and Co₉S₈ phases, while XPS identified mixed Ni²⁺/Ni³⁺ and Co²⁺/Co³⁺ states with strong Ni-S/Co-S bonding, indicating enhanced electron delocalization. Electrochemical measurements in 1 M KOH demonstrated outstanding OER activity, with NCS/CS/CNFs requiring only 324 mV overpotential at 10 mA cm⁻², a Tafel slope of 125.7 mV dec⁻¹, and low charge-transfer resistance (0.33 Ω cm²). They also achieved a high areal capacitance of 1412.5 μF cm⁻² and maintained a stable current density for >5 h. For methanol oxidation, the composite delivered 150 mA cm⁻² at 0.1 M methanol, ~1.6 times that of CS and 1.3 times that of NCS, while maintaining stability for 18,000 s. This bifunctional activity underscores the synergy between conductive CNFs and hierarchical sulfides, offering a scalable route to durable electrocatalysts for water splitting and direct methanol fuel cells. Full article

Phycocyanin (PC) is a type of alga-derived protein which exerts the role of light harvesting in Spirulina and Cyanophyta cells. Studies have widely proved that phycocyanin exhibits antineoplastic functions, while investigations on its bioactive peptides remain poorly documented. In previous work, three phycocyanin-derived peptides (PCPs: PCP1-3), which exerted anticancer effects in non-small cell lung cancer (NSCLC) cells, were successfully identified. In consideration of the in vitro instability of bioactive peptides, this study firstly investigated the stabilization and function of phycocyanin-derived peptides loaded by nanoparticles (NPs). Herein, Lipid-core NPs (PCPs@LEC–CS–PEG, diameter less than 100 nm) were prepared by interfacial deposition of a polymer using lecithin (LEC, liposome core shell), chitosan (CS, coating material) and polyethylene glycol (PEG, stabilizer). The results indicate that the embedding of LEC liposomes could significantly increase the stability of PCPs through promoting their resistance to high temperature (68.256 ± 3.26%), pH (60.17 ± 3.67%) and protease. Moreover, the modification of NPs by PEG and CS could enhance the protective effects on PCPs. Furthermore, in vitro phenotypic experiments confirmed that the inclusion of PCPs@PEG-CS–LEC NPs also significantly increased the inhibitory activities of PCPs against multiple NSCLC cells including A549, H1299 and LTEP-a2 cells, compared with non-embedded PCPs. The results of this work could lay a theoretical foundation for the further development and utilization of peptides derived from phycocyanin, and also for the investigation of the antineoplastic effects of bioactive peptides. Full article

In this study, core–shell Ln₂O₃@carbon nanoparticles (core = Ln₂O₃ and shell = carbon; Ln = Tb and Ho) were synthesized for the first time by preparing Ln₂O₃ nanoparticles through a polyol method, followed by carbon coating using D-glucose as a carbon precursor in aqueous media. The synthesized Ln₂O₃@carbon nanoparticles exhibited good colloidal stability in solution and very low toxicity in in vitro cellular cytotoxicity tests. They exhibited paramagnetic magnetization values that increased with increasing applied field strength, resulting from spin–orbit magnetic moments of 4f-electrons; hence, they yielded negligible r₁ (<0.1 s⁻¹mM⁻¹) and appreciable r₂ values (3.446 and 3.677 s⁻¹mM⁻¹ for Ln = Tb and Ho, respectively) at 3 T, highlighting their potential as T₂ MRI contrast agents, particularly at high MR fields. In addition, the carbon coating shell exhibited photoluminescence at 460 nm, suitable for applications in fluorescence imaging probes. Full article

Developing bifunctional electrocatalysts that simultaneously enable green hydrogen production and water purification is essential for advancing sustainable energy and environmental technologies. In this study, we present Cu@Pd core–shell nanostructures fabricated through template-assisted electrodeposition of Cu, followed by galvanic Pd modification on pyrolytic graphite electrodes (PGEs). The optimised catalyst exhibited superior hydrogen evolution reaction (HER) activity, with an onset potential of 70 mV, a low Tafel slope of 33 mV dec⁻¹ and excellent stability during prolonged HER operation. In addition to hydrogen evolution, Cu@Pd/PGE shows significantly enhanced nitrate reduction reaction (NRR) activity compared to Cu/PGE in both alkaline and neutral conditions. Under ideal conditions, the catalyst achieved 60% nitrate removal with high selectivity towards ammonia and minimal nitrite formation, emphasising its superior performance. This enhanced bifunctionality arises from the synergistic Cu–Pd interface, facilitating efficient nitrate adsorption and selective hydrogenation. Despite their high catalytic activity for both HER and NRR, the Cu@Pd nanostructures could often emerge as a versatile platform for integration into sustainable hydrogen production and an effective denitrification process. Full article

Background. MiR-218 is a micro-RNA expressed in two isoforms (miR-218-1 and miR-218-2) in the brain and, within the mesencephalic area, it represents a specific regulator of differentiation and functional maturation of the dopamine-releasing neurons (DAn). Deletion of miR-218 isoforms within the midbrain alters the expression of synaptic mRNAs, the neuronal excitability of DAn of the substantia nigra pars compacta (SNpc), and their ability to release dopamine (DA) within the dorsal striatum. Objectives. Here we have investigated if miR-218 impacts the function of the DAn population adjacent to SNpc, the mesencephalic ventral tegmental area (VTA) innervating the nucleus accumbens (NAcc), and the medial prefrontal cortex. Methods. With the use of miR-218-1, miR-218-2, and double conditional knock-out mice (KO1, c-KO2, c-dKO), we performed electrophysiological recordings in VTA DAn to investigate firing activity, measurements of DA release in NAcc slices by constant potential amperometry (CPA), and in vivo behavioral analysis. Results. We find that KO1 VTA neurons display hyperexcitability in comparison with c-KO2, c-dKO, and wild type (WT) neurons. DA efflux in the NAcc core and shell is reduced in all single- and double-conditional KO striatal slices in comparison with controls. The KO1 mice display a tendency toward an anxiety-like trait, as revealed by the elevated plus maze test. Conclusions. Our data indicate that miR-218-1 is the isoform that mainly regulates VTA DA neuron excitability whereas both miR-218-1 and miR-218-2 impair DA release in the mesoaccumbens pathway. Full article

Encapsulation of lubricating agents has many advantages, as it helps to protect them from external factors, oxidation and degradation, can support their controlled and prolonged release, and also preserves the environment from accidental contamination with these substances. In our experiments various types of thermo-responsive, paraffin wax capsules capable of safely transporting liquid and semi-solid lubricants were designed, fabricated and tested. Lubricating oils were primarily encapsulated inside hemispherical wax shells closed with special caps, but also in wax spherocylinders and two-compartment structures. Greases were protected with wax coatings with the thickness ranging from 0.187 to 0.774 mm. The payload release from our core–shell capsules occurred not only due to the exerted mechanical force but also in a controlled manner upon prolonged contact with a heated surface. The wax shells of the capsules lying on the plate, whose temperature was increased at a rate of 0.025°C/s, began to melt gradually, starting from ≈55.5 °C. This temperature-triggered lubricant liberation can be useful when, for example, a machine element becomes excessively hot due to friction. The wax itself also has lubricating properties, so the crushed or melted coating cannot be treated as waste, but only as an additional factor supporting lubrication. The practical applications of our wax capsules were demonstrated with five examples. Full article

The direct deposition of highly concentrated polyelectrolyte complexes based on poly(ethyleneimine) (PEI) and poly(sodium methacrylate) (PMANa) onto inorganic sand microparticles (F100 and F200) resulted in the formation of versatile core-shell composites with fast removal properties in dynamic conditions toward anionic charged pollutants. Herein, in situ-generated nonstoichiometric PEI/PMANa polyelectrolyte complexes were directly precipitated as a soft organic shell onto solid sand microparticles at a 5% mass ratio (organic/inorganic part = 5%, w/w%). The sorption of an anionic model pollutant (Indigo Carmine (IC)) onto the composite particles in dynamic conditions depended on the inorganic core size, the flow rate, the bed type (fixed or fluidized) and the initial dye concentration. The maximum sorption capacity, after 10 cycles of sorption/desorption of IC onto F100@P5% and F200@P5%, was between 16 and 18 mg IC/mL composite. The newly synthesized core-shell composites could immobilize IC at a high flow rate (8 mL/min), either from concentrated (C_IC = 60 mg/L) or very diluted (C_IC = 0.2 mg/L) IC aqueous solution, demonstrating that this type of material could be promising in water treatment or efficient in solid-phase extraction (concentration factor of 2000). Full article

Dry reforming of methane and ethanol is a promising catalytic process for the conversion of carbon dioxide and hydrocarbon feedstocks into synthesis gas (H₂/CO), which serves as a key platform for the production of fuels and chemicals. Over the past decade, substantial progress has been achieved in the design of catalysts with enhanced activity and stability under the demanding conditions of these strongly endothermic reactions. This review summarizes the latest developments in catalyst systems for DRM and EDR, including Ni-based catalysts, perovskite-type oxides, MOF-derived materials, and high-entropy alloys. Particular attention is given to strategies for suppressing carbon deposition and preventing metal sintering, such as oxygen vacancy engineering in oxide supports, rare earth and transition metal doping, strong metal–support interactions, and morphological control via core–shell and mesoporous architectures. These approaches have been shown to improve coke resistance, maintain metal dispersion, and extend catalyst lifetimes. The review also highlights emerging concepts such as multifunctional hybrid systems and innovative synthesis methods. By consolidating recent findings, this work provides a comprehensive overview of current progress and future perspectives in catalyst development for DRM and EDR, offering valuable guidelines for the rational design of advanced catalytic materials. Full article

We synthesized emeraldine salts of poly(aniline-co-aniline-2-sulfonic acid) capped with camphorsulfonic acid (CSA), forming spherical nanoparticles (NPs), i.e., CSA-capped P(ANi-co-ASNi), and demonstrated their efficacy as gas sensor elements. The synthesized core–shell spherical NPs, averaging 265 nm in diameter, feature a CSA shell with a porous thin-film morphology, characterized by the uneven distribution of fine particulate domains across the outer surface of the positively charged P(ANi-co-ASNi) cores. This uniquely heterogeneous shell architecture facilitates stable charge transport at the core–shell interface, enhances resistance to ambient humidity, and promotes efficient interaction with organic gas molecules. The CSA-capped P(ANi-co-ASNi) sensors reliably detected low concentrations of acetone (1–5 ppm) and water vapor (1–28% RH) under ambient conditions. Furthermore, the sensors exhibited superior stability across varying temperature, humidity, and cyclic performance, outperforming conventional pure PANiNi. Full article

Crop diseases cause significant losses in agricultural production; early capture and identification of disease spores enable disease monitoring and prevention. This study experimentally optimized the preparation of Au@Ag NRS (Gold core@Silver shell Nanorods) sol as a Surface-Enhanced Raman Scattering (SERS) enhancement reagent via a modified seed-mediated growth method. Using an existing microfluidic chip developed by the research group, disease spores were separated and enriched, followed by combining Au@Ag NRS with Crop Disease Spores through electrostatic adsorption. Raman spectroscopy was employed to collect SERS fingerprint spectra of Crop Disease Spores. The spectra underwent baseline correction using Adaptive Least Squares (ALS) and standardization via Standard Normal Variate (SNV). Dimensionality reduction preprocessing was performed using Principal Component Analysis (PCA) and Successive Projections Algorithm combined with Competitive Adaptive Reweighted Sampling (SCARS). Classification was then executed using Support Vector Machine (SVM) and Multilayer Perceptron (MLP). The SCARS-MLP model achieved the highest accuracy at 97.92% on the test set, while SCARS-SVM, PCA-SVM, and SCARS-MLP models attained test set accuracy of 95.83%, 95.24%, and 96.55%, respectively. Thus, the proposed Au@Ag NRS-based SERS technology can be applied to detect airborne disease spores, establishing an early and precise method for Crop Disease detection. Full article

A sheet-type sinter-bonding material was developed to form thermally stable and highly heat-conductive joints suitable for wide-bandgap (WBG) semiconductor dies and high-heat-flux devices, and its bonding characteristics were investigated. To enhance the cost-competitiveness of the bonding material, Ag-coated Cu (Cu@Ag) particles were employed as fillers instead of conventional Ag particles. To facilitate accelerated sintering, a bimodal particle size distribution comprising several micron- and submicron-sized particles was adopted by synthesizing and mixing both size ranges. For sheet fabrication, a decomposable resin was used as the essential binder component, which could be removed during the bonding process via thermal decomposition. This approach enabled the formation of a sintered bond line composed entirely of Cu@Ag particles. Thermogravimetric and differential thermal analyses revealed that the decomposition of the resin in the sheet occurred within the temperature range of 290–340 °C. Consequently, sinter-bonding conducted at 350 °C and 370 °C exhibited significantly superior bondability compared to bonding at 330 °C. In particular, sinter-bonding at 350 °C for just 60 s resulted in a highly densified joint microstructure with a low porosity of 7.6% and high shear strength exceeding 25 MPa. The formation of the bond line was initiated by sintering between the outer Ag shells of the adjacent particles. However, with increasing bonding time or temperature, sintering driven by Cu diffusion from the particle cores to the outer Ag shells, particularly in the submicron-sized particles, was progressively enhanced. These results obtained from the fabricated sheet-type materials demonstrate that, even with the use of resin, rapid solid-state sintering between filler particles combined with the removal of resin through decomposition enables the formation of a metallic bond line with excellent thermal conductivity. Full article

This study explores the challenge of using anthocyanin-rich natural deep eutectic solvent (NADES) extracts to produce electrospun nanofibers for biodegradable freshness indicators. Red cabbage was extracted with two choline chloride-based NADESs (with citric or lactic acid), modified with 10–50% ethanol to lower viscosity, and compared with a standard 50% ethanol-water solvent. The citric acid NADES with 30% ethanol gave the highest anthocyanin yield (approx. 0.312 mg/mL, more than 20 times higher than the ethanol extract at approx. 0.014 mg/mL). For fiber fabrication, a polymer carrier blend of poly(ethylene oxide) (PEO) and sodium alginate (Alg) was employed, known to form hydrogen-bonded networks that promote chain entanglement and facilitate electrospinning. Despite this, the NADES extracts could not be electrospun into nanofibers, while the ethanol extract produced continuous, smooth fibers with diameters of approximately 100 nm. This highlights a clear trade-off; NADESs improve anthocyanin recovery, but their high viscosity and low volatility prevent fiber formation under standard electrospinning conditions. To leverage the benefits of NADES extracts, future work could focus on hybrid systems, such as multilayer films, core-shell fibers, or microcapsules, where the extracts are stabilized without relying solely on direct electrospinning. In storage tests, ethanol-extract nanofibers acted as effective pH-responsive indicators, showing visible color change from day 4 of meat storage. At the same time, alginate films with NADES extract remained unchanged after 12 days. These results highlight the importance of striking a balance between chemical stability and sensing sensitivity when designing anthocyanin-based smart packaging. Full article

Low-temperature oxidation of titanomagnetite in oceanic basalts distorts the primary thermoremanent magnetization (TRM) signal essential for reconstructing Earth’s magnetic field history, though the specific impact of magma intrusion-induced oxidation on paleointensity preservation remains poorly constrained. This investigation simulates such oxidation processes using a novel experimental design involving isothermal annealing (260 $°$C; 50 µT field; durations 12.5–1300 h) of Red Sea rift basalts (P72/4), employing the Thellier-Coe method to quantify how chemical remanent magnetization (CRM) overprinting affects TRM fidelity under controlled field orientations aligned either parallel or perpendicular to the initial TRM. Results demonstrate two-sloped Arai-Nagata diagrams with reliable TRM preservation below 360 $°$C but significant alteration artifacts above this threshold. Crucially, field orientation during oxidation critically influences accuracy: parallel configurations maintain fidelity (±3% deviation at $Z=0.48$), while perpendicular fields introduce systematic biases (38% overestimation at $Z=0.15$; 20% underestimation at $Z>0.48$), which is attributable to magnetostatic interactions in core-shell grain structures. These findings establish that paleointensity reliability in basalt prone to low-temperature oxidation depends fundamentally on the alignment between oxidation-era magnetic fields and primary TRM direction, necessitating stringent sample selection and directional constraints in marine paleomagnetic research to mitigate CRM-TRM interference. Full article

The synthesis of lanthanide fluorescent nanoparticles and the investigation of their fluorescence sensing applications have attracted a great deal of attention in materials science over the past decades. In this study, we designed and synthesized a core–shell fluorescent nanoparticle based on dual-center emission from the europium and terbium complexes, and demonstrated its application as a ratiometric fluorescence sensor for the detection of 2,6-pyridinedicarboxylic acid (DPA). The europium complex is embedded in the inner core, providing a stable fluorescence signal at 617 nm, while the terbium complex is positioned in the outer shell and exhibits a fluorescence “Turn-ON” response at 545 nm upon interaction with DPA molecules. The fluorescence intensity ratio F₅₄₅/F₆₁₇ exhibits a sensitive response to the DPA concentration. Experimental results demonstrate that the as-prepared SiO₂@Eu@SiO₂@Tb nanoparticle exhibits a linear response in the DPA concentration range of 10–100 μM, with a detection limit (LOD) of 1.38 μM and well selectivity for DPA sensing. This strategy offers new insights into the development of novel lanthanide-based ratiometric fluorescence sensors. Full article