The dielectric relaxation and optical properties of the chlorobenzene-iodobenzene-n-hexane ternary system were investigated in the microwave region (lambda = 0.75-6.32 cm) over the temperature range from -40 to +30 degrees C using dielectric spectroscopy combined with Density Functional Theory (DFT) calculations. The influence of temperature and composition on dielectric relaxation behavior was analyzed. It was established that increasing iodobenzene content enhances relaxation time and dielectric strength due to stronger dipole-dipole interactions and higher molecular polarizability, whereas the addition of n-hexane weakens intermolecular interactions and reduces relaxation times. The relaxation processes exhibit thermally activated non-Debye behavior. DFT calculations provided microscopic insight into the dielectric and optical response through analysis of the dielectric function, polarizability, refractive index, optical conductivity, and electric susceptibility. The results indicate that iodine-induced polarizability and n-hexane-mediated dielectric screening govern the relaxation behavior and optical response of the ternary system. These findings contribute to the understanding of dielectric relaxation in multicomponent aromatic liquid systems and may be relevant for the design of dielectric and microwave materials.
The pH and viscosity of the microenvironment play a crucial role in numerous processes that significantly affect the normal functioning of cells. As a rule, abnormal levels of pH and viscosity are associated with cellular disorders leading to cancer, diabetes, cardiovascular and neurodegenerative diseases. Therefore, the design and synthesis of molecular sensors for simultaneous detection of pH and viscosity are enjoyed increasing research interest. However, the reported probes for pH and viscosity detection were rarely identified as molecular logic gates, and their logic behavior was largely undisclosed. Herein, we report on the synthesis of a new water-soluble fluorescent probe based on 1,8-naphthalimide and 4-amino-1,2,4-triazole for simultaneous detection of temperature, pH and viscosity as an excellent platform for molecular logic gates, thanks to the existence of a temperature-, viscosity- and pH-sensitive TICT process. Due to its remarkable properties, the new probe is capable of executing classical AND and INH logic gates at the molecular level, as well as a molecular logic gate using binary input-ternary output. The excellent biocompatibility, high cell permeability and lack of toxicity as well as the presence of a suitable anchor group at the N-1,8-naphthalimide position, capable of targeting different intracellular sites, demonstrate the great potential of the new compound as a promising DNA recognition stain for real-time imaging of nuclear pH and viscosity in cancer cells, and as an auspicious tool in diagnostics- and drug-delivery-related studies in medicine and cell biology.
Streptomycin sulfate (SM), a representative aminoglycoside antibiotic, is widely used for the treatment of tuberculosis and Gram-negative bacterial infections, but residues in water and food-related matrices may pose risks to human health. Here, we developed a portable sensing platform for on-site antibiotic residue monitoring. The platform uses carbon dots prepared from 4-aminobutyric acid and 5-amino-o-cresol by a hydrothermal route as a composite fluorescent nanoprobe. The probe showed a quantum yield of 3.8% in water and enabled both visual recognition and quantitative detection of SM. As the SM concentration increased, the probe color shifted from blue-green to yellow, allowing direct visual readout. The fluorescence assay showed a linear response over 0-500 & micro;M with a limit of detection (LOD) of 0.47 & micro;M, whereas the smartphone-assisted colorimetric readout was linear over 0-600 & micro;M with an LOD of 0.21 & micro;M. Selectivity, interference-resistance and spiked-recovery tests in real samples indicate that the method provides a sensitive, stable and matrix-tolerant route for low-cost screening of SM in food and environmental samples.
Recently, the application of photocatalysis on the treatment of antibiotics contamination has been received increasing attention. Developing high active photocatalytic material is crucial to realize the efficient degradation of antibiotics. In the present work, a hierarchical 1D/3D S-scheme heterostructure Bi4V2O11/In2S3 was successfully fabricated with facile hydrothermal strategy. The synthesized Bi4V2O11/In2S3 was characterized by s series of measures. The combination of in-situ X-ray photoelectron spectroscopy (XPS), band alignment, and generation of reactive species demonstrate the S-scheme charge migration mechanism of Bi4V2O11/In2S3 heterojunction. The catalytic performance of Bi4V2O11/In2S3 was assessed by the photocatalytic degradation of tetracycline (TC). Bi4V2O11/In2S3 heterojunction exhibits significantly enhanced photoactivity relative to the bare Bi4V2O11 and In2S3. The optimal heterojunction (BI-20%) shows superior photocatalytic activity toward TC degradation, achieving an TC removal efficiency of 87% after visible-light irradiation of 120 min. In addition, BI-20% demonstrated satisfactory mineralization ability, excellent structural stability, good recyclability, and strong resistance to coexisting ions, humic substances, and pH variation. The enhanced photocatalytic performance originated from the synergistic effect of multidimensional configuration and S-scheme charge migration in promoting the separation and migration of photogenerated charge carriers. As well as, the rational design of energy band arrangement of Bi4V2O11 and In2S3 enables center dot O2- , center dot OH, and h+ to serve as the principal active species. The current work supplies a feasible strategy for constructing efficient photocatalytic materials for the environment restoration.
Melanin formation represents a fundamental research focus that bridges diverse fields, including cell biology, medicine, food science, cosmeceutical science, and materials science. Nevertheless, the molecular mechanisms that drive this process, particularly the common principle behind light-accelerated food browning and skin pigmentation, remain poorly understood. Using a tyrosinase-catalyzed monophenol oxidation model, we found that light exposure affects neither the initial enzymatic oxidation of monophenols to dopachrome (DC) nor the subsequent polymerization of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into melanin. Instead, our findings reveal that light enhances melanin formation by specifically acting on the DC intermediate. Visible light promotes melanin formation via an excited-state proton transfer mechanism within DC. By contrast, under UV irradiation, a competing photolysis reaction involving the phenolic hydroxyl group of DC occurs at a higher excited state, which diminishes the efficiency of melanin formation. This stronger promoting effect of visible light, relative to UV light, was consistently demonstrated in both homogeneous solutions and mushroom systems. Our work elucidates a key photochemical pathway in melanin formation and provides a mechanistic basis for developing strategies to regulate photo-induced pigmentary disorders and control food browning.
