Search Results (2,438)

Current tumor diagnostics rely on fluorodeoxyglucose (FDG)-PET imaging, but FDG’s short half-life and high cost limit its widespread use. Infrared (IR) probes are emerging as non-radioactive alternatives to conventional tracers for tissue section and other in vitro imaging applications. Because cells and tissues are relatively free of absorption peaks between 1800 and 2200 cm⁻¹, metal-carbonyl complexes, especially cyclopentadienylrhenium(I) tricarbonyl (Cp[Re(CO)₃]) derivatives, absorb strongly in this window and provide robust platforms for bioconjugation. Furthermore, Cp[Re(CO)₃] fragments can be introduced into organic substrates via an elegant three-component reaction that simultaneously forges the cyclopentadienyl-metal and cyclopentadienyl-substituent bonds. As a result, the functionalized half-sandwich complex is obtained in a single step without any special handling issues. We have therefore properly modified a glucose molecule with that complex and developed a novel glucoconjugated Cp[Re(CO)₃] probe that enables IR-based visualization of diseased cells at 2100 cm⁻¹, offering a non-invasive, non-radioactive histological tool and a promising basis for future medical imaging devices. Full article

Mixed amine/sulfolane (TMS) biphasic solutions have gained attention for their adjustable structure–activity relationships and lower regeneration energy. In this study, monoethanolamine (MEA) is employed as the main absorbent and polyamine as the co-absorbent, which are subsequently mixed with the phase separation promoter sulfolane (TMS) to form ternary biphasic solvent systems. Polyamine co-absorbents include 3-Dimethylaminopropylamine (DMAPA), 3-Diethylaminopropylamine (DEAPA), and Diethylenetriamine (DETA). Phase separation, absorption, and desorption performances were systematically studied. Reaction and phase separation mechanisms were elucidated through ¹³C nuclear magnetic resonance (NMR) spectroscopy. The overall mass transfer coefficients (K_G) were measured using a wetted wall column (WWC). Variations in the amine-to-sulfolane concentration ratio showed minimal impact on phase volume, while temperature and solvent composition significantly influenced phase separation behavior. All three solvents exhibited superior CO₂ capture performance, with CO₂ loadings in the rich phases ranging from 4.09 to 4.71 mol/L and over 96.82% of CO₂ concentrated in them, cyclic capacities reached or exceeded 3 mol/L, and regeneration energy consumption was 29.63–55.51% lower than 5 M MEA. ¹³C NMR analysis indicated that multiple N atoms in polyamines promoted the formation of additional ionic species during CO₂ absorption, thereby enhancing phase separation completeness. Furthermore, K_G values for the ternary systems exceeded that of conventional MEA, with the MEA/DEAPA/TMS system exhibiting a 1.7-fold increase. These findings demonstrated the industrial potential of MEA/polyamine/TMS biphasic solvents for efficient CO₂ capture. Full article

The existing scientific literature indicates that flowable short fiber-reinforced composites (SFRCs) can be used for direct restoration due to their favorable mechanical properties. However, there is a lack of data on the mechanical properties of SFRCs designed specifically for indirect CAD/CAM restorations. This study aims to fabricate a novel experimental SFRC CAD/CAM block and evaluate its fracture toughness and polishability as an indirect restoration in comparison with different conventional resin-based CAD/CAM blocks with different compositions. Fourier-transform infrared spectroscopy (FTIR) was employed to analyze the chemical structure of the Experimental SFRC group, while the microstructure of specimens from each group was examined using scanning electron microscopy (SEM). Then, this study divided the specimens into three groups—Group 1 (Grandio blocks), Group 2 (Cerasmart 270), and Group 3 (Experimental SFRC)—with 30 specimens in each group. Each group was then subdivided into sub-groups for the fracture toughness test, which evaluated resistance to crack propagation, and the surface roughness test, which assessed surface topography. FTIR analysis showed that the experimental SFRC exhibited distinct spectral changes after polymerization, confirming successful chemical reactions and network formation. SEM analysis showed that the Experimental SFRC block had a polymeric matrix with randomly oriented, well-dispersed short fibers. Grandio blocs exhibited a dense nanohybrid structure with irregular fillers, while Cerasmart 270 displayed a more uniform microstructure with evenly dispersed nano-sized spherical fillers. The Experimental SFRC showed the highest fracture toughness (2.758 MPa·√m), surpassing the other groups (p < 0.05) and highlighting its superior resistance to crack propagation. Regarding surface roughness Ra, the novel Experimental SFRC group (0.182) presented a significant difference compared to other groups (p < 0.05) but within clinical acceptance, and they can be well polished for clinical use after milling. The Cerasmart 270 block showed the lowest surface roughness Ra (0.135) among the groups, which is attributed to its filler size, geometry, and composition, resulting in a smoother surface. The higher fracture toughness of the Experimental SFRC among the groups suggests superior resistance to crack propagation, attributed to the incorporation of short fibers that enhance energy absorption and reduce brittleness, thereby supporting its suitability for high-stress-bearing clinical applications. Full article

In this work, a stable silver nanoparticle (AgNPs) with strong surface plasmon resonance absorption (Abs) signals was synthesized using light-wave technology. In the absence of aptamers, AgNPs can aggregate in a given concentration of salt solution, resulting in significant changes in color. After adding the aptamer (Apt), it was observed that the aptamer can coordinate with AgNPs and adsorb on the surface of AgNPs, thereby maintaining the stability of the nanosol. In the presence of mercury ions (Hg²⁺), their high-affinity reaction with the aptamer compromised the latter’s protective effect on AgNPs, causing the color of the system to change again. Based on this, a simple and rapid new Abs method for detecting Hg²⁺ can be constructed. The linear range was 2.5 × 10⁻³–10.00 μmol/L, and the detection limit (DL) of the system was 2.03 nmol/L. Full article

The paper presents the results of experimental testing of a PLA-based composite, modified with powdered cork and a compatibilizer. The purpose of applying these additives was to evaluate their influence upon the physical, structural and functional properties of the obtained material. Specimens with various cork and compatibilizer contents were analyzed to evaluate the synergic interaction between the polymer base and the filler. The tests of the mechanical properties, water absorption and FTIR analysis were carried out. The results confirmed that the cork filler improved the PLA-based composite both in terms of the utility and ecological aspects. Despite a certain mechanical deterioration, the properties remain fully acceptable for packaging applications. Also, the improvement of hardness at higher cork content was observed, which points to effective phase interaction and a good adherence of the components. The FTIR spectroscopy confirmed chemical stability of the base and the lack of unwanted degradation reactions. The obtained composite is an innovative, biodegradable polymer material that utilizes natural waste in a way which is both economic and environmentally friendly. The obtained results point to a high application potential of this kind of composite, mainly in the packaging industry and in the field of ecological utility materials. Full article

Mancozeb (MCZ), a widely used fungicide in agricultural production, has been reported as an environmental endocrine disruptor, posing serious risks to ecosystems and human health. In this work, multivalent Co-MOF nanozymes (MVCM) with excellent oxidase-like activity were synthesized, which can promote the oxidation of 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) into a blue oxidative product (ABTS^•+), with an obvious absorption peak at 415 nm. With the addition of MCZ, the ABTS^•+ was reduced to colorless ABTS through the REDOX reactions between MCZ and ABTS^•+. Based on the unique reducing behavior of MCZ, a nanozyme-based colorimetric detection platform was proposed for the detection of MCZ, with a linear range of 3–27 μM and a detection limit (LOD) of 0.15 μM. Furthermore, the sensor was integrated with smartphones and test strips, establishing a portable smartphone-based platform for the real-time, on-site, and visual quantitative detection of MCZ. The detection concentration range was 15–90 μM, with LOD as low as 15 μM. The assay exhibited high adaptability in practical applications. In summary, this work provided a simple, accurate, and low-cost approach for visual determination of MCZ without complicated instruments and procedures. Full article

Hydrogen peroxide (H₂O₂) is a widely used green oxidant, yet its conventional industrial production via the anthraquinone process is energy-intensive and environmentally unfriendly. Photocatalytic oxygen reduction reaction (ORR) presents a sustainable alternative for H₂O₂ synthesis, but its practical application is limited by inefficient light absorption, low charge separation efficiency, and sluggish reaction kinetics. In this work, we developed a metal-free carbon-based photocatalyst (QCDs) acquired by modifying quercetin with carbon dots (CDs) for efficient photogeneration of H₂O₂. The optimized QCDs achieved a H₂O₂ production rate of 1116.32 μmol·h⁻¹·g⁻¹, which is 40.3% higher than that of pristine quercetin. Comprehensive analysis with transient potential scanning (TPS), transient photovoltage (TPV), and photocurrent transient (TPC) measurements reveal that the photocatalytic ORR follows a two-step single-electron pathway. It is worth noting that CDs not only promote the generation and transfer of photogenerated electrons but also boost oxygen adsorption. Our work demonstrates the synergy of integrating biomass-derived materials with nanostructural engineering and optimizing the system with data-driven approaches for enhanced photocatalysis. Full article

An epoxy resin can be crosslinked with an imidazole-based ionic liquid (IL), whose excess, provided its high melting temperature, can potentially form a dispersed phase to store thermal energy and produce a phase-change material (PCM). This work investigates the crosslinking of diglycidyl ether of bisphenol A (DGEBA) using 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) at its mass fractions of 5, 10, 20, 40, and 60%. The effect of [EMIM]Cl on the viscosity, curing rate, and curing degree was studied, and the thermophysical properties and morphology of the resulting crosslinked epoxy polymer were investigated. During the curing, [EMIM]Cl changes its role from a crosslinking agent (an initiator of homopolymerization) and a diluent of the epoxy resin to a plasticizer of the cured epoxy polymer and a dispersed phase-change agent. An increase in the [EMIM]Cl content accelerates the curing firstly because of the growth in the number of reaction centers, and then the curing slows down because of the action of the IL as a diluent, which reduces the concentration of reacting substances. In addition, a rise in the proportion of [EMIM]Cl led to the predominance of the initiation over the chain growth, causing the formation of short non-crosslinked molecules. The IL content of 5% allowed for curing the epoxy resin and elevating the stiffness of the crosslinked product by almost 7 times compared to tetraethylenetriamine as a usual aliphatic amine hardener (6.95 GPa versus 1.1 GPa). The [EMIM]Cl content of 20–40% resulted in a thermoplastic epoxy polymer capable of flowing and molding at elevated temperatures. The formation of IL emulsion in the epoxy matrix occurred at 60% [EMIM]Cl, but its hygroscopicity and absorption of water from surrounding air reduced the crystallinity of dispersed [EMIM]Cl, not allowing for an effective phase-change material to be obtained. Full article

Titanium dioxide (TiO₂) nanoparticles (NPs) have garnered significant attention as photocatalysts for degrading organic pollutants, particularly synthetic dyes such as rhodamine B (RhB), methylene blue, methyl orange, and others. The impact of several synthesis methods, including sol–gel, hydrothermal, and chemical vapor deposition (CVD) techniques, on the electrical and morphological properties of TiO₂ NPs has been studied, emphasizing the distinctive physicochemical properties of TiO₂ NPs, including their extensive surface area, significant oxidative capacity, and remarkable chemical stability, which are important in the recent advancements in their use for RhB degradation. A detailed examination of TiO₂’s photocatalytic mechanism shows that it is based on the generation of reactive oxygen species (ROS) by photoinduced electron–hole pair formation under ultraviolet (UV) light exposure. In wastewater treatment, TiO₂ degrades RhB into less harmful byproducts by the generation of electron–hole pairs that initiate redox reactions under sunlight. This study includes a thorough overview of significant factors influencing photocatalytic efficacy. The parameters include particle size, crystal phase (anatase, rutile, and brookite), surface changes, and the incorporation of metal or non-metal dopants to enhance visible light absorption. Researchers continually seek methods to overcome challenges, including restricted visible-light responsiveness and rapid electron–hole recombination. The investigated approaches include heterojunction generation, composite development, and co-catalyst insertion. This review article aims to address the deficiencies in our understanding of TiO₂-based photocatalysis for the degradation of RhB and to propose enhancements for these systems to enable more efficient and sustainable wastewater treatment in the future. Full article

A LaFeO₃/Bi₄Ti₃O₁₂ heterojunction photocatalyst composite was constructed for the removal of tetracycline (TC). The structure, morphology, and elemental composition of the composite were systematically characterized using tools such as XRD, SEM, and XPS. The results from characterization jointly verified the successful construction of a LaFeO₃/Bi₄Ti₃O₁₂ heterojunction. UV–vis DRS analysis further revealed a narrowing of the optical bandgap from 3.29 eV to 2.24 eV, which enhanced visible-light absorption. Characterization via XPS identified the presence of Fe²⁺/Fe³⁺ mixed valence states, while bismuth predominantly existed in the stable Bi³⁺ state. Under simulated sunlight (300 W xenon lamp) irradiation, the photocatalytic performance of LaFeO₃/Bi₄Ti₃O₁₂ was systematically evaluated. The results demonstrated that the LaFeO₃/Bi₄Ti₃O₁₂ composite achieved a removal efficiency of 95% for TC within 120 min, with a reaction rate constant of 0.023 min⁻¹. The construction of heterojunction greatly increased not only the removal efficiency but also the reaction rate. For instance, the first-order reaction rate constants of LaFeO₃/Bi₄Ti₃O₁₂ were 3.8 and 4.7 times higher than those of pure LaFeO₃ and Bi₄Ti₃O₁₂. TC removal by the composite was affected by dosage, initial TC concentration, and pH of the water. The composite exhibited the best performance at a dosage of 1.6 g/L with a pH around 7–8 and an initial TC concentration less than 20 mg/L. Anions such as Cl⁻ and NO₃⁻ had minimal impact on its photocatalytic activity, whereas H₂PO₄⁻, humic acid, showed inhibitory effects. Free radical trapping experiments further confirmed that holes (h⁺) and hydroxyl radicals (·OH) were the primary active species in the process. Full article

Bio-oil’s high chlorine content severely hinders its application, because of its high corrosivity. Catalytic pyrolysis is an effective method for the dechlorination of bio-oil. Herein, the performances of the acidified-γ-Al₂O₃ modified with alkaline and alkaline earth metal compounds were investigated. It was found that NaOH was a better loading material than Ca(NO₃)₂ or Mg(NO₃)₂ in the support of acidified-γ-Al₂O₃. The optimal loading amount of NaOH was 5 wt% in the range of 1 wt%–15 wt%, and the better calcination temperature was 600 °C, compared with 800 °C. When catalyzed with Na/Al₂O₃ (5%, 600 °C), the organic chlorides content in bio-oil from the pyrolysis of corn straw at 500 °C was significantly reduced from 150 ppm to 29 ppm, while the inorganic chlorides content barely changed. NaAlO₂ was generated in Na/Al₂O₃ from the solid-phase reaction between NaOH and Al₂O₃ by calcination. When Na/Al₂O₃ (5%,600 °C) and Na₂CO₃ were both used in two layers in a fixed-bed reactor, the organic and inorganic chlorides in bio-oil simultaneously significantly decreased, respectively, to 57 ppm and 23 ppm. The decrease in chlorides benefits the deep dechlorination of bio-oil by absorption or catalytic hydrodechlorination in a post-treatment process, which reduces the consumption of absorbent or hydrogen. Full article

The use of photocatalytic CO₂ reduction as a green technology has attracted the attention of scholars. Nevertheless, the lower visible-light utilisation and photocatalytic efficiency of catalysts remain a challenge. In this work, Bi_xO_yBr_z photocatalysts were synthesised using a hydrothermal method by adjusting the molar ratio of Bi(NO₃)₃·5H₂O and C₁₉H₄₂BrN (Bi:Br ratio) and the pH value of the precursor solution. The obtained samples were characterised, and the CO₂ reduction performance was tested. The results showed that the phase composition for most of the samples was Bi₄O₅Br₂, and BiOBr or Bi₅O₇Br was also confirmed in a small number of samples. Owing to the effects of pH and the Bi:Br ratio on the reaction process, BiOBr→Bi₄O₅Br₂→Bi₅O₇Br transformation occurred. Acidic conditions are conducive to the formation of BiOBr. In alkaline environments, bismuth-rich Bi₄O₅Br₂ or even Bi₅O₇Br easily forms. Bi₄O₅Br₂ has self-assembled microsphere and irregular polyhedron morphologies. The polyhedron Bi₄O₅Br₂ results in CO and CH₄ yields of 10.34 μmol·g⁻¹·h⁻¹ and 1.86 μmol·g⁻¹·h⁻¹ in CO₂ reduction, respectively. Although the microsphere Bi₄O₅Br₂ has a maximum light absorption wavelength of 438 nm, the polyhedron Bi₄O₅Br₂ has the best photocatalytic CO₂ reduction performance and CO selectivity. This work describes the controllable preparation of Bi₄O₅Br₂ at various pH values and Bi:Br ratios and the optimisation of its photocatalytic performance. Full article

This study presents a custom-built, portable multispectral imaging (MSI) system integrated with computer vision for sodium nitrite detection via the Griess reaction on paper-based substrates. The MSI system was used to investigate the absorption characteristics of sodium nitrite at concentrations from 0 to 10 ppm across nine spectral bands spanning 360–940 nm on para-aminobenzoic acid (PABA) and sulfanilamide (SA) substrates. Upon forming azo dyes with N-(1-naphthyl) ethylenediamine (NED), the PABA and SA substrates exhibited strong absorption near 545 nm and 540 nm, respectively, as measured by a spectrometer. This agrees with the 550 nm MSI images, in which higher sodium nitrite concentration regions appeared darker due to increased absorption. A concentration-correlation analysis was conducted for each spectral band. The normalized difference index (NDI), constructed from the most and least correlated bands at 550 nm and 940 nm, showed a stronger correlation with sodium nitrite concentration than the single best-performing band for both substrates. The NDI increased the coefficient of determination (R²) by approximately 19.32% for PABA–NED and 19.89% for SA–NED. This improvement was further confirmed under varying illumination conditions and through comparison with a conventional smartphone RGB imaging approach, in which the MSI-based NDI showed substantially superior performance. The enhancement is attributed to improved contrast, illumination normalization by the NDI, and the narrower spectral bands of the MSI compared with RGB imaging. In addition, the NDI framework enabled effective image segmentation, classification, and visualization, improving both interpretability and usability and providing a practical guideline for developing more robust models with larger training datasets. The proposed MSI system offers strong advantages in portability, sub-minute acquisition time, and operational simplicity, enabling rapid, on-site, and non-destructive chemical analysis. Full article

Cysteine (Cys) is an essential thiol in food and biological systems, yet its selective quantification remains challenging due to interference from structurally related analytes such as homocysteine (Hcy) and glutathione (GSH). Here, we report a hemicyanine-based, turn-off fluorescent probe (PRH) that undergoes Cys-triggered cyclization to release PRH-OH, resulting in fluorescence quenching. PRH exhibits near-infrared emission at 630 nm, enabling low self-absorption and reduced background. The probe affords a broad linear range (0–100 μM) with a detection limit of 0.344 μM, along with high selectivity over Hcy, GSH, and 18 other amino acids. In food matrices (garlic, onion, and dried red pepper), PRH achieved recoveries of 98.8–101.3% with RSD < 2% (n = 3), demonstrating analytical robustness. Live-cell imaging in HeLa cells further verified practical responsiveness: N-ethylmaleimide-mediated thiol depletion increased PRH fluorescence, whereas Cys replenishment decreased it, consistent with the probe’s turn-off behavior. DFT calculations support an intramolecular charge-transfer change upon Cys reaction, correlating with the observed spectral shift. Overall, PRH provides a simple and selective platform for reliable Cys quantification in food samples and for visualizing Cys dynamics in cells. Full article

Five types of fruit seed oils have been described from the perspective of their potential use in the synthesis of biopolyols. The overall goal is to increase the participation of biopolyurethanes in polymer production, aligning with the European Green Deal. Blackcurrant, cherry, grape, pomegranate, and watermelon seed oils were characterized by iodine value, acid value, density, average molecular weight, viscosity, and fatty acid profile. The thermal properties of the oils were also determined using thermogravimetry (TGA) and differential scanning calorimetry (DSC). In order to obtain reactive compounds for the synthesis of biopolyols, the vegetable oils were modified using the transesterification reaction with triethanolamine. The resulting biopolyols were characterized by their hydroxyl number, acid number, density, average molar mass, and viscosity. The biopolyols were then used to produce thermal-insulating polyurethane foams by completely replacing petrochemical polyols with counterparts derived from fruit seeds. The obtained foams were described by their closed cell content, apparent density, thermal conductivity coefficient, dimensional stability, maximum stress at 10% deformation, thermal stability, oxygen index, and water absorption. In addition, an analysis of the foaming process revealed that the properties of fruit seed oil after chemical modification had an impact on the properties of the open-cell polyurethane foams and the foaming process itself. Full article