Search Results (226)

The selective hydrogenation of phenol to cyclohexanone is a pivotal reaction for producing nylon precursors. Conventional Pd/C catalysts, however, suffer from weak metal–support interactions, leading to size heterogeneity and agglomeration of Pd nanoparticles, which degrades their activity and stability. Herein, we report a facile argon plasma treatment to engineer rich defects on an activated carbon (AC) support, resulting in a highly dispersed and stable catalyst (denoted as PL-Pd@AC_Ar). Characterization results indicate that the abundant carbon defects in PL-Pd@AC_Ar enhance the anchoring of Pd precursors, ensure the uniform dispersion of Pd nanoparticles, and effectively modulate their electronic structure. Consequently, the plasma-enabled PL-Pd@AC_Ar catalyst achieves 99.9% phenol conversion with 97% selectivity to cyclohexanone at a mild temperature of 70 °C and maintains exceptional stability over six consecutive cycles. This work provides a robust and efficient strategy for the surface engineering of carbon supports to design high-performance hydrogenation catalysts. Full article

This computational study investigates the thermal decomposition of 1,2,4-triazol-3(2H)-ones and their thione analogues using Density Functional Theory (DFT). The reaction proceeds via a concerted, six-membered cyclic transition state, primarily driven by the breaking of the N–N bond. A key finding is that the accuracy of the calculated activation energies (Ea) strongly depends on the choice of DFT functional. For sulfur-containing systems (thiones), the hybrid functional APFD (with 25% Hartree–Fock exchange) provides the most reliable results, effectively describing their higher polarizability. In contrast, for oxygen-containing systems (triazolones), the dispersion-corrected functional B97D-GD3BJ (with 0% Hartree–Fock exchange) delivers superior accuracy by better modeling electrostatic and dispersion interactions. The -CH₂CH₂CN group at the N-2 position acts not only as a protecting group but also stabilizes the transition state through non-covalent interactions. Electron-withdrawing substituents slightly increase the E_a, while electron-donating groups decrease it. Sulfur analogues consistently show significantly lower activation energies (by ~40 kJ/mol) than their oxygen counterparts, explaining their experimentally observed faster decomposition. This work establishes a dual-methodology computational framework for accurately predicting the kinetics of these reactions, providing valuable insights for the regioselective synthesis of biologically relevant triazole derivatives via controlled pyrolysis. Full article

Alopecia areata (AA) is an autoimmune-mediated nonscarring alopecia with limited therapeutic options and frequent relapses. Exosomes, nanosized extracellular vesicles secreted by various cell types, have recently emerged as potential regenerative and immunomodulatory therapies. The aim of the study is to review the clinical and preclinical evidence regarding the efficacy and safety of EV-based therapies for alopecia areata. a systematic search of PubMed, Embase, Web of Science, and Cochrane Library was performed from 2020 to 2 October 2025. Inclusion criteria were original studies (clinical, preclinical, in vivo, in vitro) investigating exosome-derived interventions for AA. Outcomes of interest were hair regrowth, immune modulation, follicular regeneration, and safety. A total of 499 records were retrieved from electronic database searches. After deduplication and application of the inclusion/exclusion criteria, 40 studies met the eligibility criteria for the review. Of these, two were clinical studies (one retrospective cohort, one case report), while the remainder comprised five animal (in vivo) studies, six in vitro studies, and sixteen mixed translational studies (in vitro/in vivo ± clinical). Experimental studies reported hair coverage improvements of 50–99% and, in one instance, 30% regrowth in totalis and 16% in partialis, with nearly complete regrowth in incipient alopecia. Clinical reports noted density increases of 9–31 hairs per cm² (e.g., from 121.7 to 146.6 hairs/cm², p < 0.001) and improvements in hair count, length, and thickness. Several studies detailed activation of the Wnt/β-catenin pathway along with enhanced dermal papilla and hair follicle stem cell function, as well as anti-inflammatory effects. Reported safety profiles were favorable; when adverse events occurred, they were limited to mild, transient local reactions with no severe systemic issues. EV-based therapy is a novel and biologically plausible approach for AA, but robust randomized controlled trials (RCTs) are lacking. Standardization of small EV sources, doses, and delivery methods is essential before clinical translation. Full article

Background: 8-Quinolinol and its derivatives are drawing significant attention across various disciplines due to their remarkable versatility. These compounds are well-known for their exceptional chelating ability, forming stable metal complexes via their nitrogen and oxygen electron donor atoms. This main characteristic determines their broad utility. Biological activity can also be explained by the chelating capacity, which allows 8-quinolinol to bind to essential metal ions such as Fe, Zn, Cu, and others. This chelation disrupts metal-dependent biological processes in target cells or organisms, leading to a range of effects, including antimicrobial, anticancer, antifungal, and neuroprotective activities. On the other hand, the biological activity of pyrazole derivatives is attributed to their heterocyclic structure, which allows for interactions with biological targets that can lead to enzyme inhibition, receptor antagonism, radical scavenging, and other effects. Objective: This work aimed to synthesize and characterize novel diazene compounds derived from 8-quinolinol or 2-methyl-8-quinolinol and pyrazole amines, and to evaluate their antimicrobial and anticancer activities. Methods: The compounds have been synthesized by coupling diazonium salts obtained from the diazotization of heterocyclic amines with 8-quinolinol and its derivative, 2-methyl-8-quinolinol. The careful selection of reaction conditions enabled the synthesis of high-purity products. The compounds were characterized by 1D and 2D NMR, FT-IR spectroscopy, UV-Vis spectroscopy, and LC-HRMS analysis. The biological activity of the newly synthesized compounds was evaluated following the protocols of EU-OPENSCREEN, a European Research Infrastructure Consortium (ERIC) initiative dedicated to supporting early drug discovery. Results: By combining diazonium salts obtained from 3-methyl-1H-pyrazol-5-amine and ethyl 5-amino-3-methyl-1H-pyrazole-4-carboxylate with the aforementioned coupling agents, four novel 8-quinolinol derivatives were synthesized. The further hydrolysis of the ethoxy carbonyl functional group allowed its conversion to a carboxylic functional group, thus expanding the series of new compounds to six members. Several compounds from the series have proven to be biologically active against several human pathogenic microorganisms and the Hep-G2 cancer cell line. Conclusions: The combination of two well-known biologically active scaffolds through a classic diazo coupling reaction allowed the synthesis of novel biologically active compounds, which showed promising results as possible antifungal and anticancer agents. These results represent a foundation for future studies, which will include a broader biological screening and in vivo studies. Full article

An efficient and sustainable electrochemical method for [4+2] and [2+2] cycloadditions has been developed, enabling the facile synthesis of six- and four-membered carbocycles. This metal-free strategy leverages constant-current electrolysis to generate key radical cation intermediates in situ from electron-rich olefins, eliminating the need for stoichiometric oxidants or transition-metal catalysts. The reaction demonstrates broad compatibility with various cyclopentadiene and styrene derivatives, constructing complex bicyclic frameworks with high efficiency and selectivity. Notably, the practicality of this protocol is demonstrated by its gram-scale implementation. A portion of the desired product could be isolated in good yield simply by filtration, avoiding the need for column chromatography. This work establishes electrosynthesis as a powerful and scalable alternative to conventional thermal and photochemical strategies, aligning with the principles of green chemistry. Full article

Bio-waste from potato shell agro-waste-based photocatalyst is introduced using potato shell integrated with Fe₃O₄ nanoparticles as a novel photocatalyst for photo-Fenton oxidation reaction. The catalyst was prepared via thermal activation of biochar, followed by co-precipitation of magnetite nanoparticles, resulting in a stable and reusable material. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques augmented with the energy dispersive X-ray spectroscopy (EDX) analysis with elemental mapping were used to assess the prepared sample. The prepared material, PtS200–Fe₃O₄, is then applied for oxidizing Procion Blue dye using biochar-supported magnetite catalyst. The oxidation process was evaluated under varying operational parameters, including pH, temperature, catalyst loading, oxidant dosage, and dye concentration. Results revealed that the system achieved complete dye removal within 20 min at 60 °C and pH 3, demonstrating the strong catalytic activity of the composite. Furthermore, the kinetic modeling is evaluated and the data confirmed that the degradation followed first-order kinetics. Also, the thermodynamic parameters indicated low activation energy with PtS200–Fe₃O₄ composite in advanced oxidation processes. The system sustainability is also assessed, and the reusability test verified that the catalyst retained over 70% efficiency after six consecutive cycles, highlighting its durability. The study confirms the feasibility of using biochar-supported magnetite as a cost-effective, eco-friendly, and efficient catalyst for the treatment of textile effluents and other dye-contaminated wastewater. Full article

This study characterized the biological response of MG-63 cells to synthetic, hydroxyapatite scaffolds (HAsint) fabricated via fused filament fabrication. Scaffolds were compared to 2D plate-adherent cultures using six assays: cell morphology and distribution with scanning electron microscopy and confocal laser scanning microscopy; cell proliferation and cytotoxicity via WST-1 tetrazolium assay; relative osteogenic gene expression through reverse-transcription–quantitative polymerase chain reaction, and protein synthesis via multiplex immunoassay. Data were analyzed using one-way ANOVA. Results confirmed high cell viability and uniform distribution on HAsint scaffolds. Proliferation increased significantly over 7 days, though direct cytotoxicity also increased, likely due to the static conditions of the experiment and, subsequently, the high ion reprecipitation from scaffold degradation. Importantly, HAsint scaffolds significantly enhanced osteogenic marker expression of phosphatase alkaline (ALPL), osteopontin (OPN), and osteocalcin (OCN) genes, and elevated concentrations of interleukins (IL)-6, IL-8 and matrix metalloproteinase 1 compared to plate-adherent controls. It can be concluded that 3D-printed HAsint scaffolds support robust osteogenic differentiation and proliferation despite inducing a transient cytotoxic response in vitro. The marked upregulation of key osteogenic genes and proteins confirms the scaffolds’ bioactivity and highlights their potential for bone tissue engineering applications. Full article

Recently, researchers have been focused on the recycling as well as transforming of bio-waste streams into a valuable resource. Banana peels are promising for such application, due to their wide availability. In this context, the integration of banana peel-derived biochar with environmentally benign magnetite has significantly broadened its potential applications as a solar photocatalyst compared to the conventional photocatalysts. The materials are mixed in varied proportions of Ban-Char500-Mag@-(0:1), Ban-Char500@Mag-(1:1) and Ban-Char500@Mag-(2:1) and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) augmented with dispersive X-ray spectroscopy (EDX). Such modification is leading to an improvement in its application as a solar photocatalyst using the photochemical solar collector facility. The study discusses the factors controlling acetaminophen removal from aqueous effluent within 30 min of solar illumination time. Furthermore, the highlighted optimum parameters are pH 3.0, using 10 mg/L of the Ban-Char500@Mag-(1:1) catalyst and 100 mg/L of the hydrogen peroxide as a Fenton combination system for removing a complete acetaminophen from wastewater (100% oxidation). Also, the temperature influence in the oxidation system is studied and the high temperature is unfavorable, which verifies that the reaction is exothermic in nature. The catalyst is signified as a sustainable (recoverable, recyclable and reusable) substance, and showed a 72% removal even though it was in the six cyclic uses. Further, the kinetic study is assessed, and the experimental results revealed the oxidation process is following the first-order kinetic reaction. Also, the kinetic–thermodynamic parameters of activation are investigated and it is confirmed that the oxidation is exothermic and non-spontaneous in nature. Full article

The paper describes the conversion of carbon dioxide into methanol in a chemical reactor under standard operating conditions. Electro-analytical techniques, cyclic voltammetry, and chrono-amperometry characterize the process. The electrochemical redox reaction develops using various catalyzers to evaluate the performance of the carbon dioxide conversion into methanol process under variable chemical conditions. The results of the applied technique showed an incomplete redox reaction with an electronic change of z = 2.84 on average, below the ideal number, z = 6, that may be due to methanol decomposition (reverse reaction) because the system operates with a reaction constant above the equilibrium value. The methanol production may improve by draining the methanol/water solution from the chemical reactor to reduce the methanol concentration in the electrochemical cell, shifting the forward reaction towards the formation of methanol, increasing the electron change number, which approaches the ideal value, and improving the methanol production efficiency. The draining process shows a significant increase in methanol formation, which depends on the draining flow rate and the catalyzer type. A simulation process shows that if we operate in optimum conditions, with no methanol decomposition through a reverse reaction, the redox reaction fulfills the ideal condition of maximum electronic change. The experimental tests validate the simulation results, showing a relevant increase in the electron change number with values up to z = 4.2 for optimum draining flow rate conditions (0.2 L/s). The experimental results show a relative increase factor of 4.7 in methanol production, meaning we can produce more than four times more methanol compared with no draining techniques. The data analysis shows that the draining flow rate has a threshold of 0.2 L/s, beyond which the extent of the reaction reverses, reducing the methanol formation due to a chemical reaction disequilibrium. The paper concludes that using the draining method, the methanol production mass rate increases significantly from an average value of 20.9 kg/h for non-draining use, considering all catalyzer types, to a range between 91.9 kg/h and 104.3 kg/h, depending on the flow rate. Averaging all values for different flow rates and comparing with the non-draining case, we obtain an absolute methanol production mass rate of 77 kg/h, meaning an incremental percentage of 469.1%, more than four times the initial production. Although the proposed methodology looks promising, applying this procedure on an industrial scale may suffer from restrictions since the chemical reactions intervening in the methanol formation do not perform linearly. According to experimental tests, the best option among the six catalyzers used for methanol production is the plain copper, with copper oxides (Cu₂O, CuO) and copper Sulphur (CuS) as feasible alternatives. Full article

The use of fish skin grafts as xenografts is a promising alternative for wound healing. Several studies have shown fish skin grafts to be a safer and more effective option compared to other alternatives, due to the large amount of fatty acids, including omega-3, which have been proven to promote wound healing. The purpose of this study was to evaluate the efficacy of fish skin grafts as wound dressing. A literature search up to March 2024 was conducted using the electronic databases of PubMed, Cochrane, and ScienceDirect. A total of 158 patients from six studies were included in this systematic review. All studies showed early wound healing using fish skin grafts; one study showed that wound healing was halved compared to paraffin gauze. Complete wound healing using fish skin grafts was noted as early as 30 days. Out of 114 patients treated with fish skin grafts, 1 patient showed signs of infection, and no patients showed allergic reactions. One study also found that fish skin grafts provide satisfactory wound scar quality. This study concludes that fish skin grafts are a great alternative and should be considered in wound treatment. The high omega-3 component that is preserved in fish skin grafts promotes faster wound healing and contains antibacterial agents that prevent infection. However, randomized control trials with a larger sample size are recommended to further assess the efficacy of fish skin grafts. Full article

The phase equilibria of the Si-C-Cu ternary system at 700 °C and 810 °C were experimentally investigated for the first time. Fifteen key alloys were prepared via powder metallurgy and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Isothermal sections were constructed based on the identified equilibrium phases. At 700 °C, eight single-phase regions and six three-phase regions—(C)+(Cu)+hcp, (C)+hcp+γ-Cu₃₃Si₇, (C)+γ-Cu₃₃Si₇+SiC, γ-Cu₃₃Si₇+SiC+ε-Cu₁₅Si₄, SiC+ε-Cu₁₅Si₄+η-Cu₃Si(ht), and SiC+(Si)+η-Cu₃Si(ht)—were determined. At 810 °C, nine single-phase regions and seven three-phase regions were identified. The solubility of C and Si/Cu in the various phases was quantified and found to be significantly higher at 810 °C compared to 700 °C. Key differences include the presence of the bcc (β) and liquid phases at 810 °C. The results demonstrate that higher temperatures promote increased mutual solubility and reaction tendencies among Cu, C, and Si. Motivated by these findings, the influence of vacuum hot pressing parameters on SiC-fiber-reinforced Cu composites (SiC_f/Cu) was investigated. The optimal processing condition (1050 °C, 60 MPa, 90 min) yielded a high bending strength of 998.61 MPa, attributed to enhanced diffusion and interfacial bonding facilitated by the high-temperature phase equilibria. This work provides essential fundamental data for understanding interactions and guiding processing in SiC-reinforced Cu composites. Full article

Cyclic voltammetry (CV) is an accessible, readily available, non-expensive technique that can be used to search for the interaction of compounds with DNA and detect the strongest DNA-binding from a set of compounds, therefore allowing for the optimization of the number of cytotoxicity assays. Focusing on this electrochemical approach, the study of twenty-seven camphorimine silver complexes of six different families was performed aiming at detecting interactions with calf thymus DNA (CT-DNA). All of the complexes display at least two cathodic waves attributed respectively to the Ag(I)→Ag(0) (higher potential) and ligand based (lower potential) reductions. In the presence of CT-DNA, a negative shift in the potential of the Ag(I)→Ag(0) reduction was observed in all cases. Additional changes in the potential of the waves, attributed to the ligand-based reduction, were also observed. The formation of a light grey product adherent to the Pt electrode in the case of {Ag(OH)} and {Ag₂(µ-O)} complexes further corroborates the interaction of the complexes with CT-DNA detected by CV. The morphologic analysis of the light grey material was made by scanning electronic microscopy (SEM). The magnitude of the shift in the potential of the Ag(I)→Ag(0) reduction in the presence of CT-DNA differs among the families of the complexes. The complexes based on {Ag(NO₃)} exhibit higher potential shifts than those based on {Ag(OH)}, while the characteristics of the ligand (^AL-Y, ^BL-Y, ^CL-Z) and the imine substituents (Y,Z) fine-tune the potential shifts. The energy values calculated by docking corroborate the tendency in the magnitude of the interaction between the complexes and CT-DNA established by the reaction coefficient ratios (Q_[Ag-DNA]/Q_[Ag]). The molecular docking study extended the information regarding the type of interaction beyond the usual intercalation, groove binding, or electrostatic modes that are typically reported, allowing a finer understanding of the non-covalent interactions involved. The rationalization of the CV and cytotoxicity data for the Ag(I) camphorimine complexes support a direct relationship between the shifts in the potential and the cytotoxic activities of the complexes, aiding the decision on whether the cytotoxicity of a complex from a family is worthy of evaluation. Full article

The catalytic activity of monolayer and bilayer boron-doped edge black phosphorene nanoribbons (BPNRs) as electrocatalysts for the nitrogen reduction reaction (NRR) was investigated using first-principles calculations based on density functional theory (DFT). The results indicate that boron incorporation facilitates effective N₂ adsorption at specific BPNR edges, thereby achieving superior NRR electrocatalytic performance. Through NRR screening criteria, six candidate edges (B@ZZ₃-1, B@ZZ₄-1, B@AC₀-1, B@ZZ₀^AA-1, B@ZZ₁^AB-3, and B@ZZ₄^AA-3) were identified. Electronic property analysis revealed that boron doping significantly reduces the bandgap of BPNRs and enhances catalytic activity by promoting electron accumulation at boron sites. Free energy pathway calculations demonstrated that B@AC₀-1, B@ZZ₀^AA-1, and B@ZZ₁^AB-3 exhibit overpotentials of 0.19 V, 0.28 V, and 0.15 V, respectively, during the NRR process, outperforming other phosphorus-based catalysts in activity. Full article

This work investigated the optical characteristics of BaWO₄ nanoparticles that were produced through direct mechanochemical synthesis at varying speeds and times. This research expands upon our previous study. We demonstrated that the mechanochemical activation of the precursor of BaCO₃ and WO₃, at elevated milling speeds (850 rpm), facilitates the formation of tetragonal BaWO₄ in a reduced reaction time. The final products were characterized by scanning electron microscopy (SEM), as well as Raman, infrared (IR), UV-Vis diffuse reflectance, and photoluminescence spectroscopies. The crystallite sizes and particles shapes were determined by X-ray diffraction and SEM analysis. Round particles with a size below 50 nm formed under different milling conditions. The Raman spectra of the synthesized samples confirmed the presence of a scheelite-type structure with the typical six distinct vibrational peaks. The symmetry of the structural WO₄ groups was determined by IR spectroscopy. The absorption spectra of both samples exhibited intensive peaks at 210 nm, and the calculated optical band gaps of BaWO₄ were 5.10 eV (3 h/500 rpm) and 5.24 eV (1 h/850 rpm). A strong (400 nm) and weak (465 nm) emission were observed for the BaWO₄ that was obtained at a higher milling speed, while wider emission at 410 nm was visible for the BaWO₄ that was prepared at a lower milling speed. The CIE coordinates of the mechanochemically synthesized BaWO₄ were located within the blue area, exhibiting various positions. Full article

Zinc-halogen batteries are usually based on two-electron transfer reactions from X⁻ to X₂. However, the halogen is capable of being further oxidized to higher valence states, thereby achieving the higher capacity of zinc- halogen batteries. Here, a six-electron reaction based on I⁻/I⁺ and Br⁻/Br⁰ is activated successfully by introducing KI into the electrolyte. ZIF-8-derived porous carbon (ZPC), serving as the host of halogen, effectively suppresses polybromide/polyiodide shuttle owing to the chemisorption/physical adsorption. Additionally, the adsorption of I⁻ on the surface of the zinc anode effectively inhibits the growth of dendrites and the formation of by-products. Consequently, zinc-bromine batteries exhibit outstanding electrochemical performance, including a specific capacity of 345 mAh g⁻¹ at 1 A g⁻¹ and an excellent capacity retention of 80% after 3000 cycles at 2 A g⁻¹. This strategy provides a novel way for enhancing the electrochemical performance of zinc-halogen batteries. Full article