Search Results (191)

Background/Objectives: Understanding the unique properties of human neurons is crucial for advancing knowledge of brain function and facilitating clinical translation. This study explores the use of photopharmacology, specifically a photoswitchable ligand, Phthalimide-Azo-Iperoxo (PAI), to modulate cortical activity in human brain slices. Methods: Human cortical tissue was obtained from patients undergoing resective neurosurgery for pharmacoresistant epilepsy. The inactive cis isomer of PAI (200 nM) was bath-applied to brain slices exhibiting slow-oscillatory activity, producing no effect on the ongoing network activity. Subsequent illumination of the slices with white light induced photoconversion to trans-PAI, the active form of the compound. Results: Photoactivation of PAI selectively activated M₂ muscarinic acetylcholine receptors, resulting in a significant increase in oscillatory frequency accompanied by reductions in both Up-state and Down-state durations. Conclusions: In this proof-of-concept study, our findings provide preliminary evidence that photopharmacology can selectively modulate slow oscillations in human cortical circuits, highlighting its potential as a tool for investigating human cortical dynamics. By extending observations previously made in animal models to human tissue, this work establishes the feasibility of photopharmacological modulation in human cortical tissue and provides a foundation for future translational research. Full article

Synthetic dyes from textile effluents represent a major environmental concern due to their persistence and toxicity. Reactive Black 5 (RB5) is widely used in the textile industry and is commonly applied as a model azo compound in sorption studies. This study comparatively evaluates the sorption performance of raw and carbonized sorbents derived from industrial hemp (Cannabis sativa L.) biowaste using an integrated experimental and theoretical approach. The sorbents were prepared through washing, drying, and phosphoric acid-assisted carbonization followed by pyrolysis. Structural and physicochemical properties were characterized using elemental analysis, FTIR spectroscopy, and SEM microscopy. Sorption performance toward RB5 was investigated through batch kinetic and equilibrium experiments, supported by kinetic (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models) and isotherm (Langmuir, Freundlich, and Temkin) modeling. Molecular docking simulations were performed to provide mechanistic insight into dye–sorbent interactions. Both materials exhibited rapid sorption kinetics, reaching equilibrium within approximately 45 min, with the pseudo-second-order model suggesting that surface-controlled interactions dominate the sorption rate. Molecular modeling, based on extensive conformational sampling, indicated a strong binding affinity between RB5 and cellulose-based structures, primarily associated with hydrogen bonding and other favorable noncovalent interactions. In contrast, graphene-based models revealed sorption governed by π–π interactions and confinement effects, supporting the experimentally observed differences between raw and carbonized sorbents. Full article

The discharge of metal-complex dyes from textile industries poses significant environmental challenges due to their chemical stability and resistance to conventional biological treatment. This study examined the degradation of Acid Black 194 (AB–194), a 1:2 chromium-complex azo dye, using Co²⁺-activated peroxymonosulfate (PMS). A central composite design based on response surface methodology was used to evaluate the effects of Co²⁺ (5.93–20.07 µM), PMS (1.67–7.33 mM), and dye (13.79–56.21 mg L⁻¹) concentrations on decolorization and mineralization. The polynomial models demonstrated strong predictive accuracy (R² > 0.9896), identifying Co²⁺ and dye concentrations as the most influential factors. Under optimal conditions (18.0 µM Co²⁺, 6.5 mM PMS, 20.0 mg L⁻¹ dye), 99.19% decolorization was achieved at 30 min and 41.43% TOC removal at 240 min. Degradation kinetics were described by a mechanistic model incorporating 15 elementary reactions that comprise the Co²⁺/Co³⁺ redox cycle, radical generation, and dye oxidation, yielding a global R² of 0.9617. Estimated rate constants for dye oxidation (k₁₄ = 3.52 × 10⁹ M^–1 s^–1 for and k₁₅ = 2.00 × 10¹⁰ M^–1 s^–1 ) were consistent with values reported for aromatic compounds in sulfate radical systems. Radical contribution analysis confirmed sulfate radicals as the principal oxidizing species, accounting for 96.75% of the overall process. Full article

The textile industry wastewater contaminated by azo dyes usually contains a certain amount of salinity. Therefore, screening for microorganisms capable of degrading azo dyes in saline environments is of great significance. In this study, the decolorizing activity of azo dye methyl red (MR) by Klebsiella aerogenes WH2 (WH2), newly isolated from soil, was evaluated. WH2 was able to decolorize 92.4% and 86.0% of MR at concentrations of 200 mg/L and 300 mg/L within 24 h, respectively. Given that WH2 exhibited enhanced growth and superior degradation capacity in the presence of 2.5% NaCl compared to salt-free conditions, it can be classified as a slight halophile. Approximately 87.7% of MR was removed by WH2 in the presence of 10.0% NaCl within 24 h. Azoreductase activity assays indicated that WH2 retained higher enzyme activity in the presence of NaCl concentrations not exceeding 7.5%. The degradation products and putative metabolic pathways for MR degradation by WH2 were analyzed using FTIR and LC-MS. Phytotoxicity analysis based on seed germination of Vigna radiata indicated that the degradation products of MR exhibited less toxicity than the parent compound. The high degradation efficiency of MR under high salt concentrations makes WH2 a promising candidate for the treatment of saline textile wastewater. Full article

Azo dyes in textile industry effluents cause major environmental problems, highlighting the need to remove these compounds before discharge. The Nyex Rosalox™ (NR) process, a water treatment process that combines adsorption, electrochemical oxidation, and in situ regeneration using a patented novel graphite-based adsorbent (Nyex™ 2000 media), could potentially be used to remove azo dyes before being discharged. In this study the efficiency of the NR process for removing these compounds is assessed. Analyses indicate that (i) the Nyex™ media was able to adsorb all azo dyes quickly, with 50% of the total dye absorbed being absorbed in the first 30 min and >10% in the first minute alone and (ii) all azo dyes used were completely oxidised during the NR process without the formation of any detectable harmful byproducts that were previously observed during the electrochemical oxidation of azo dyes, with only a relatively small amount of energy needed to enable optimal electrochemical oxidation. The Nyex™ media can be consistently regenerated, maintaining its adsorptive capacity after extensive reuse, albeit the use of fresh adsorbent will always have a slightly greater adsorptive capacity. Combined, these findings suggest that the NR process can effectively destroy azo dyes with relatively low energy, proving an effective method of water treatment without producing harmful secondary pollutants. Full article

Cannabis use is generally restricted worldwide because it contains the narcotic compound Δ⁹-tetrahydrocannabinol (Δ⁹-THC). Although cannabis is detected at crime scenes using color-based primary screening methods, the details of the reaction mechanism have not yet been elucidated. In this study, we isolated the products generated during the color reaction between the diazonium salt prepared from para-nitroaniline and nine cannabinoids and determined their structures. Azo compounds 6, 11, 16, and 17 were produced from cannabidiol, cannabigerol, cannabichromene, and cannabidiolic acid, respectively, while quinoneimines 7–10 and 12–15, which contained positional isomers, were produced from cannabinol, Δ⁹-THC, and hexahydrocannabinol. The reaction barely proceeded with Δ⁹-THC acetate and HHC acetate. Full article

The main objective of the work was to prepare a series of new activated biocarbons by chemical activation of black chokeberry seed and to assess their suitability for removing cationic and anionic dyes from an aqueous medium. Activation of the precursor was performed at 550 °C with orthophosphoric acid, using conventional or microwave-assisted heating. The activated biocarbons were characterized in terms of elemental composition, textural parameters, surface morphology, acid-base character of the surface, as well as electrokinetic properties. Adsorption tests were carried out against two organic compounds: methylene blue (thiazine dye of cationic character) and Congo red (azo dye of anionic character). The influence of the initial dye concentration (5–120 mg/L), temperature (20–40 °C), and solution pH (2–10) on dye removal efficiency from the liquid phase was investigated. Additionally, kinetic adsorption tests were carried out to determine the rate and mechanism of the dyes removal process. Microwave-assisted chemical activation with H₃PO₄ proved to be a very effective approach for generating a high specific surface area (884 m²/g) and a micro/mesoporous structure, which directly increases the adsorption capacity of activated biocarbons towards cationic and anionic synthetic dyes. The maximum adsorption capacities for methylene blue and Congo red were 194.5 and 68.6 mg/g, respectively. It was also confirmed that the choice of heating method at the activation stage plays a key role in determining the physicochemical properties and adsorption performance of the activated biocarbons prepared from waste biomass. In general, carbonaceous adsorbents derived from black chokeberry seeds exhibit high potential for the treatment of dye-contaminated wastewater. Full article

The main emphasis of the current study is to develop an eco-friendly method for producing silver nanoparticles (AgNPs) using an aqueous flower extract from Talipariti tiliaceum L., and to evaluate the photocatalytic degradation of azo dyes. The synthesized AgNPs were characterized using various spectroscopical and microscopical methods. The photocatalytic capacity of AgNPs was assessed through the degradation of methylene blue (MB) and methyl orange (MO) dye under solar irradiation. The results revealed that the AgNPs were spherical in morphology and 4–15 nm in size. The phytochemical analysis showed that the bioactive compounds from the flower extract aided in the reduction of silver ions to nanoparticles. Both visual observations and spectroscopic methods confirmed the photocatalytic degradation of MB and MO dyes. The degradation processes adhered to a pseudo-first-order kinetic model, demonstrating that photocatalytic activity is time-dependent. In addition, the AgNPs demonstrated stability and reusability through four consecutive cycles with little decline in efficiency. This research contributes significantly to sustainable nanotechnology, offering a practical solution for mitigating water pollution caused by industrial dye discharges. Full article

The contamination of water bodies by industrial dyes is a critical environmental challenge due to the toxicity and persistence of these compounds in aquatic ecosystems. This study evaluated the efficiency of Trichoderma koningiopsis immobilized on Luffa cylindrica matrices for the decolorization of the azo dye Direct Black 22 (DB22), proposing a biotechnological approach for wastewater treatment. The fungus was cultivated and immobilized on matrices characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Experiments under different temperature, pH, and initial dye concentration conditions demonstrated that the immobilized system achieved up to 96% decolorization within 24 h under optimized conditions of 50 °C and pH 4, significantly outperforming the free fungus. The Luffa cylindrica matrix provided mechanical stability and a larger contact area for DB22 decolorization. Thus, the immobilized Trichoderma koningiopsis system on Luffa cylindrica stands out as a sustainable, cost-effective, and efficient alternative for dye removal from textile effluents, contributing to safer and more effective environmental practices. Full article

A review of studies has shown that aromatic azo and hydrazo derivatives are used in a wide spectrum of fields, including food, pharmaceutical, and cosmetic products, as well as in technical and electronic technologies, which has contributed to the development of new such compounds. In this work, the structures of newly obtained 4-methyl-3,5-dinitro-2-(2-phenylhydrazinyl)pyridine (4MDNPHP) and its azo derivative, 4-methyl-3,5-dinitro-2-[(E)-phenyldiazenyl]pyridine (4MDNPAP), were established by spectroscopic (NMR, IR, Raman, and UV-Vis) and emission studies. Single-crystal X-ray diffraction analysis was used to determine the molecular structure of the studied compounds, and the results were compared with DFT calculations (B3LYP/6-311G(2d,2p)). The collected X-ray data revealed that the crystal of the hydrazo compound (4MDNPHP) belongs to the triclinic space group P$\overline{1}$ (Z = 2), whereas the crystal of the azo compound (4MDNPAP) follows the symmetry of the monoclinic space group P2₁/n (Z = 4). Both presented derivatives crystallized with one molecule in the asymmetric unit. Specific properties of the hydrazo bridge C_ϕ-NH-NH-C_θ moiety and its azo counterpart C_ϕ-N=N-C_θ were considered in detail. Full article

The textile industry releases effluents containing toxic contaminants such as azo dyes, which severely affect water quality and aquatic ecosystems. This study optimized the Fe⁰/H₂O₂/UV photo-Fenton process through Response Surface Methodology (RSM) using a Box–Behnken design applied to real textile wastewater. The process relies on in situ hydroxyl radicals (•OH) generation, which degrades refractory organic compounds. Under optimal conditions (pH 3.5, 0.5 g Fe⁰, and 0.55 mL H₂O₂), the system achieved complete color removal, 91% aromatic structures degradation, and an 80% COD reduction within 3 h. Statistical validation indicated an excellent model fit (R² = 1.0; Q² = 1.0), with strong correlation between experimental and predicted results. Spectroscopic analyses (UV–Vis and FTIR) further confirmed the cleavage of chromophoric and aromatic structures, indicating efficient pollutant degradation. Overall, the findings indicate that the Fe⁰/H₂O₂/UV system is an effective and sustainable technology for treating textile wastewater, offering strong potential for industrial-scale application. Full article

Textile dyeing wastewater, rich in recalcitrant organic compounds such as azo and anthraquinone dyes, poses significant environmental concerns. This study investigates the degradation of methyl orange (MO) using two ozone (O₃) oxidation systems—O₃/H₂O₂ and O₃/K₂S₂O₈—and analyzes the degradation products and toxicity via ESR characterization. The O₃/K₂S₂O₈ system shows a higher removal rate in the initial stage (<4 min) due to rapid ·SO₄^- radical generation. However, O₃/H₂O₂ produces more ·OH radicals, leading to better overall degradation performance. The O₃/K₂S₂O₈ system is more effective for pollutants with electron-rich groups, such as Congo red and sulfamethoxazole, while O₃/H₂O₂ performs better in natural lake water. Mechanistic studies reveal that ·O₂^- is the dominant oxidizing species in O₃/H₂O₂, while ·SO₄^- and ·O₂^- dominate in O₃/K₂S₂O₈. The toxicity of degradation products is assessed, showing lower bioaccumulation and developmental toxicity in most intermediate products compared to MO. This research provides valuable insights into the use of combined ozonation-peroxidation coupling technology for effective wastewater treatment. Full article

Organophosphate (OP) and carbamate pesticides are widely employed in agriculture to facilitate the production of economically viable crops. However, pesticide contamination of food, water, and air leads to undesired human exposure. Neuronal tissue may be particularly vulnerable to pesticide toxicity during periods of neurodevelopment. Hence, this study aimed to investigate the neurotoxicity of three pesticide compounds, namely chlorpyrifos-oxon (CPO), azamethiphos (AZO), and aldicarb, on human neural progenitor cells (hNPCs) and whether toxicity differed between undifferentiated and differentiated stem cells. Undifferentiated and differentiated hNPCs were exposed to these neurotoxicants at concentrations of 0–200 µM for 24 h, and cell viability was evaluated using 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. The impact of the neurotoxicants on cellular bioenergetics was determined by quantifying cellular ATP levels and the production of reactive oxygen species (ROS) using a 2′,7′-dichlorofluorescein diacetate (DCFDA) assay. Concentration–response curves were also generated to measure their relative inhibition of AChE. The neurotoxicants induced concentration-dependent reductions in cell viability (p < 0.0001), cellular ATP levels (p < 0.0001), and the inhibition of AChE (p < 0.0001). Notably, differentiated neurons displayed higher sensitivity than undifferentiated neural stem cells (NSCs), with a toxicity threshold of ≥1 µM. ROS levels were significantly increased (p < 0.0001) following neurotoxicant exposures, more so in differentiated cells, with levels that correlated with cytotoxicity, cell death, and the induction of oxidatively damaged proteins in surviving cells. These findings suggest a central role of oxidative stress and protein oxidation in mediating the neurotoxic effects of pesticide compounds on NSCs. Furthermore, the heightened susceptibility of NSCs to pesticide toxicity after differentiation is indicative of human vulnerability during periods of neurodevelopment. Full article

The search for bioactive compounds with antioxidant properties is critical in combating oxidative stress-related diseases and advancing novel therapeutic agents. Azo dyes, traditionally used in textiles, food, and cosmetics, have recently attracted attention due to their emerging biological activities, including antioxidant potential. In this study, we synthesized and characterized 267 azo dyes derived from natural phenolic cores such as salicylic acid, syringol, and 5,6,7,8-tetrahydro-2-naphthol. Eighteen of these compounds are novel. Structural characterization was performed using NMR, UV-Vis, IR spectroscopy, and mass spectrometry. Antioxidant activity was assessed using in vitro assays with ABTS radical scavenging method. SAR analysis revealed that dyes derived from syringol and 5, 6, 7, 8-tetrahydro-2-naphthol showed the most consistent and potent antioxidant activity. Notably, azo dyes bearing fluoro and nitro substituents in the para position exhibited the lowest IC₅₀ values, highlighting the influence of electron-withdrawing groups and substitution patterns on antioxidant behavior. This work establishes a precedent for SAR-driven evaluation of azo dyes using ABTS and supports their further exploration as functional antioxidant agents in medicinal chemistry. Full article

Although cannabis is used in a wide range of fields, including medicine and pharmacology, its use is prohibited in Japan because it contains Δ⁹-tetrahydrocannabinol (Δ⁹-THC), a compound that exhibits narcotic effects. While cannabis is primarily detected via color-based screening methods at crime scenes, the reaction products and mechanisms associated with these screening methods have not been fully elucidated. To address this issue, the colored products were isolated via the diazo-coupling reactions of the major cannabinoids (cannabidiol, cannabinol, and Δ⁹-THC) in cannabis with the Fast Blue RR diazonium salt, and their structures were determined using NMR spectroscopy. As expected, azo compound 2 was formed from cannabidiol, whereas cannabinol and Δ⁹-THC produced quinoneimines 3 and 4, respectively. This study is expected to lead to the future development of more sensitive color-based reagents that produce fewer false positives. Full article