The Royal Society of Chemistry最新文献

Based on dispersive micro solid phase extraction, a magnetic ion imprinted polymer-metal organic framework (Fe₃O₄@ZIF-8@IIP) nanocomposite was prepared in this work as a selective and effective sorbent to extract and preconcentrate cadmium(II) ions in dairy samples. An effective extraction process was made possible by the magnetic properties of iron oxide nanoparticles, metal-organic framework's large specific surface area, and ion imprinted polymer's selectivity toward Cd(II) ions. Fourier transform infrared spectrometry and scanning electron microscopy were used to characterize the produced sorbent. Effective optimization factors were examined and optimized, including the volume and type of desorption solvent, the type and duration of stirring, the pH of solution, and the quantity of the sorbent. The limits of detection and quantification under optimal extraction conditions were 0.09 and 0.30 μg L^-1, respectively. The linear range, which was 0.30-100 μg L^-1, had a coefficient of determination of 0.9927. A satisfactory match was observed in the data collected after testing a certified reference material (NIST SRM 1549 powder milk) to verify the established procedure. When Cd(II) ions were determined at 10 μg L^-1 (n = 5), the approach produced relative standard deviation values of ≤3.1%. The developed technique was effectively used to determine Cd(II) ions concentration in several dairy products.

Gas sensors are essential tools for safeguarding public health and safety because they allow the detection of hazardous gases. To advance gas-sensing technologies, novel sensing materials with distinct properties are needed. Metal-organic frameworks (MOFs) hold great potential because of their extensive surface areas, high porosity, unique chemical properties, and capabilities for preconcentration and molecular sieving. These attributes make MOFs highly suitable for designing and creating innovative resistive gas sensors. This review article examines resistive gas sensors made from pristine, doped, decorated, and composite MOFs. The first part of the review focuses on the synthesis strategies of MOFs, while the second part discusses MOF-based resistive gas sensors that operate based on changes in resistance.

The evolution of granular flows generally involves solid boundaries, which add complexity to their dynamics and pose challenges to understand relevant natural and industrial phenomena. While an interesting "teapot effect" has been observed for liquid flowing over the solid surface of a teapot's spout, a similar phenomenon for discrete particles receives far less attention. In this work, we experimentally investigated the interactions between granular flows and a wedge-shaped solid edge (spout), showing that the trailing edge of the solid boundary plays a key role in causing velocity non-uniformity and splitting the flow into "dispersed" and "uniform" regions. Tuning the parameters (inclination angle, particle diameter, radii and surface roughness of the trailing edge) of the granular flow, a dimensionless number was summarized and successfully predicted the dispersion of the granular flows. Moreover, we also proved that introducing stronger cohesive forces between particles could harness the granular flows from heterogenous structures to grain clusters, which can be employed to switch between different flow regimes and regulate the dispersion behavior of particle flows. This study reveals the interaction of granular flow over complex solid boundaries, potentially offering new insights into particle-dominated flow dynamics.

Active colloids powered by self-generated gradients are influenced by nearby solid boundaries, leading to their reorientation. In this study, the tilt angles (the angle between where an active colloid moves and where it faces) were measured to be 13.3° and -33.9° for 5 μm polystyrene microspheres half coated with 10 nm Pt caps moving in 5% H₂O₂ along the bottom and top glass wall, respectively, indicating that the colloids moved with their PS (forward) caps tilted slightly toward the wall. The speeds and tilt angles of Pt Janus colloids increased consistently with increasing H₂O₂ concentration (0.5 to 10 v/v%) and Pt cap thickness (5 to 50 nm). We propose that the tilt results from a balance between gravitational torque (caused by the Pt cap's weight) and chemical activity-induced torque (from self-generated chemical gradients), qualitatively supported by finite element simulations based on self-electrophoresis. Our findings are useful for understanding how chemically active colloids move in, and interact with, their environment.

Green mold, induced by the fungal phytopathogen Penicillium digitatum, is one of the major causes of postharvest losses in citriculture. To minimize mold infections oranges are treated harshly with fungicides, edible coatings, or physical treatment, leading to evolving resistance, low consumer acceptance, or reduced crop quality, respectively. Photodynamic Inactivation (PDI) might represent an ecofriendly alternative for treatment of P. digitatum spoilage, especially if based on natural photosensitizers. Here, we introduce PDI using three formulations consisting of different concentrations of the natural photosensitizer sodium magnesium chlorophyllin (Chl), Na₂EDTA as cell-wall permeabilizing agent and a surfactant for postharvest treatment of P. digitatum. As experimental model systems (i) mycelial spheres in liquid suspension, (ii) fungal spores or (iii) a newly developed experimental setup using orange peel plugs are employed. Illumination was done by an LED device with a main wavelength of 395 nm (106 J cm^-2). The lowest concentrated photosensitizer formulation (219 µM Chl) effectively photokilled samples of model systems (i) and (ii) with 100% and 62.5% dead samples, respectively. Orange peel plugs of model system (iii) were best disinfected using the mid-concentrated formulation (475 µM Chl, 70% dead samples). Additionally, model systems (ii) and (iii) were treated with the mid-concentrated formulation and illuminated by sunlight. Eradication of P. digitatum liquid spore culture (ii) was enhanced when illuminating with sunlight (300 J cm^-2). Further, a complete disinfection of orange peel plugs (iii, 100% dead samples) was achieved with sunlight (300 J cm^-2). To evaluate the antioxidant scavenging activity post-PDI treatment with LED light (395 nm, 106 J cm^-2) a DPPH assay was performed on model system (iii). The treatment with the mid- and low-concentrated Chl formulations and LED light showed little to no change in DPPH scavenging activity when compared to the not-illuminated controls. Concisely, with this study we demonstrate that PDI using Chl-based photosensitizer formulations has an in vitro antifungal effect against P. digitatum, without altering the antioxidant scavenging activity of the fruit. Different model systems, to mimic the different stages of green mold infection, were effectively treated with Chl and sunlight.

Circadian rhythms in gut microbiota composition are crucial for metabolic function and disease progression, yet the diurnal oscillation patterns of gut microbiota in atherosclerotic cardiovascular disease (ASCVD) and their role in disease progression remain unknown. Here, we investigated gut bacterial dynamics in Apoe^-/- mice over 24 hours and elucidated dynamic changes in fecal microbiota composition and function among C57BL/6 and Apoe^-/- mice with standard chow diet or high-fat/high-cholesterol diet under ad libitum conditions. Compared with C57BL/6 mice, Apoe^-/- mice exhibited significant differences in fecal microbial composition. Rhythmicity analysis revealed that the temporal dynamics of fecal microbiota composition and function in Apoe^-/- mice differed significantly from those in C57BL/6 mice, particularly in B. coccoides-dominated oscillatory modules. Functional annotation showed that rhythmic B. coccoides strains inhibited ASCVD progression by enhancing intestinal and endothelial barrier functions. These findings demonstrate that diurnal oscillations in gut microbiota are closely associated with ASCVD progression and provide new insights for microbiota-targeted precision therapies.

Herein, using reductive radical-polar crossover as a key process, a robust and practical protocol for the N → C acyl migration reaction has been successfully developed. A variety of enamides could react with carboxylic acids for modular access to α-(hetero)aryl-α-aminoketones enabled by redox-neutral photocatalysis. This decarboxylative radical addition/acyl migration cascade process features a broad substrate scope, good functional compatibility, and mild reaction conditions.

This study presents an eco-friendly approach for synthesizing iron oxide nanoparticles using an extract from Argemone mexicana leaves, which function as reducing and stabilizing agents. The nanoparticles were thoroughly characterized using a range of techniques, including ultraviolet-visible (UV-vis) spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta potential analysis. The synthesized Fe-NPs demonstrated notable antioxidant activity, as confirmed by assays involving 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results highlight the significant antioxidant potential of these Fe-NPs. This research introduces a sustainable and innovative synthesis method for Fe-NPs, emphasizing their promising applications, particularly in fields related to antioxidant properties, as evidenced by the conducted antioxidant assays.

A multicomponent Biginelli reaction was used to produce biologically active dihydropyrimidones that were then combined with ZnO nanoparticles. Biginelli compounds synthesized with various alkyl chains were characterized using high-resolution mass spectrometry as well as ¹H- and ¹³C-NMR spectroscopy. Efficient antibacterial gels were developed by introducing the prepared Biginelli compounds and ZnO nanoparticles into a carbomer polymer matrix. Antibacterial screening revealed that the ABS-G4 gel exhibited the highest antibacterial potential, with minimum inhibitory concentrations of 16 ± 2 and 12 ± 2 μg mL⁻¹ against Escherichia coli and Staphylococcus aureus, respectively. The ABS-G4 gel was characterized using rheological studies, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and atomic force microscopy. The ABS-G4 gel was showing more antibacterial efficacy toward Gram-positive strains of bacteria than Gram-positive ones. An antibacterial dressing was formed by coating the developed gel onto a gauze dressing.

Spatially controlled confinement of catalytic enzymes within nanoshells holds substantial potential for applications in bioreactors, synthetic cells, and artificial spores. The utilization of amorphous calcium phosphate (CaP) precursors enables the extremely rapid (<5 seconds) construction of thick (∼400 nm) CaP nanoshells, stratified with distinct enzymes, on various tannic acid-primed substrates. Saccharomyces cerevisiae cells are nanoencapsulated with enzyme-embedded, multilayered CaP nanoshells in a cytocompatible manner, providing an advanced chemical tool for interfacing living cells with functional entities in a spatially controlled configuration.