Chemical Papers最新文献

The prospective uses of flexible and freestanding solar cells in lightweight, portable, and flexible energy-harvesting systems have attracted a lot of attention over the last few years. Metal organic chemical vapour deposition (MOCVD) stands out as a crucial approach for producing high-quality gallium arsenide (GaAs) films among the different processes used to produce high-performance thin-film solar cells. This review highlights the main growth processes, issues and crucial factors that affect material quality and device efficiency, while it critically investigates the use of MOCVD to produce flexible and freestanding GaAs-based solar cells. The optimization of MOCVD growth conditions, such as substrate selection, precursor flow rates, and temperature control, is given particular attention. The paper also looks at recent developments in remote epitaxy, a promising method that removes the limitations of conventional substrate-lattice matching and facilitates the production of freestanding GaAs films. The review also outlines the main obstacles, such as strain, scalability problems, and material imperfections, and it addresses performance metrics like efficiency and stability. Finally, future research and development efforts are described, with a focus on the necessity of additional growth technique optimization, the investigation of novel substrate materials, and improvements in the marketing of flexible GaAs solar cells.

This study focuses on the synthesis of boron oxide nanofibers and their use as reinforcement materials in composites. Nanofiber synthesis was carried out by electrospinning method from solutions containing of boric acid (H₃BO₃), polyvinylpyrrolidone (PVP), and sodium dodecyl sulfate (SDS). Electrospun nanofibers were characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) to find out the morphological structure, fiber diameter size, and chemical properties that change with temperature. Then they were calcined with different thermal programs. B₂O₃ formation in calcined nanofibers was proven by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The diameter distribution of the calcined fibers was visualized by SEM, with an average fiber diameter size of 76.9 ± 3.7 nm. Calcined nanofibers were functionalization with [3 (Methacryloxy)propyl] trimethoxysilane for the composites productions. The matrix was prepared from bisphenol A-glycidyl methacrylate, triethylene glycol dimethacrylate and diurethanedimethacrylate monomers. Three-point bending tests were conducted to measure the flexural strength of B₂O₃ reinforced composites, and it was determined that 7% wt of B₂O₃ nanofiber reinforcement increased the flexural strength of the pure matrix by 123.2%. When the flexural strengths of B₂O₃ fibers and particles were compared, composites reinforced with B₂O₃ particles showed 42.2% less mechanical strength.

This paper offers a novel approach featuring homogenous liquid-phase microextraction and beta-cyclodextrin for detecting azole antifungal medicines like clotrimazole and climbazole in diverse matrices. Switchable hydrophilicity solvents can be miscible or immiscible based on sample pH and vary from monophasic to biphasic depending on a trigger as extraction solvents. Adding beta-cyclodextrin to the extraction phase may boost efficiency by promoting supramolecular host–guest azole antifungal compounds. This order used dipropylamine for extraction. The recommendation is greener, faster, easier, reproducible, and cheaper. The method was easier without centrifugation. The work examined the impact of operational extraction factors including concentrations of beta-cyclodextrin, volume of dipropylamine, amounts of acid/base solution, and ionic strength of the sample. Under optimal conditions, vortex assisted-switchable hydrophilicity solvents-homogeneous liquid-phase microextraction, extraction time: around 2 min, showed good linearity in the range of 40.0–11000.0 ng.mL⁻¹ and determination coefficients 0.9998 for climbazole, 10.0–11000.0 ng.mL⁻¹ determination coefficients 1.0000 for clotrimazole, and the limits of detection were found to be 12.0 ng.mL⁻¹ for climbazole and 3.0 ng.mL⁻¹ for clotrimazole. The vortex-assisted-beta-cyclodextrin-Switchable hydrophilicity solvents-homogeneous liquid-phase microextraction method quantified azole fungicides in water, milk, plasma, and tablet samples. Spiking recoveries of 98.2–101.8% revealed the approach can detect imidazole fungicides in samples.

Graphical abstract

This study examined biofilm-producing Staphylococcus epidermidis isolates from Menoufia University Hospitals, Egypt, and the antibiofilm effects of AgNPs, chlorhexidine, and iodine. About 162 staphylococcal isolates from clinical samples were phenotypically identified as S. epidermidis using Vitek 2, with 71 (43.82%) verified. Tissue culture plate detection and conventional PCR genotyping for ica genes revealed biofilm-producing phenotypes. S. epidermidis isolates developed biofilms (94.36%, 67/71) when subjected to various antiseptic concentrations and durations, including chlorhexidine digluconate (0.025%, 0.035%, and 0.05%), povidone-iodine (3.5%, 7.5%, and 10%), and AgNPs (100, 75, 50, and 25 μg/ml). All biofilms were suppressed by chlorhexidine at 0.05% concentration and varying exposure durations. All povidone-iodine concentrations worked at 10 min; however, 3.5% was ineffective at 5 min. Only 10% concentration prevented biofilm growth at 1 min. AgNPs' antibiofilm impact is concentration-dependent, with the most effective concentration at 100 μg/ml (79.42%), followed by 75 μg/ml (74.91%), 50 μg/ml (70.71%), and 25 μg/ml (62.83%). Chlorhexidine was efficacious in vitro at a therapeutically available concentration of 0.05% and a short exposure duration of 1 min, but povidone-iodine required greater concentrations and longer exposure times. The study found that AgNPs have varying antibiofilm effects, with the most robust inhibition at 100 μg/ml concentration.

The Allura Red dye is classified as an azo-type dye, known for its carcinogenic and mutagenic properties. It is commonly discharged into the environment through various industrial effluents, including those from the textile, food, drug, and cosmetic industries. This study is focused on investigating the degradation of Allura Red dye utilizing advanced oxidation techniques such as hydrogen peroxide, Fenton, hydrodynamic cavitation (HC), and hybrid methods (HC/H₂O₂ and HC/Fenton) for the first time. Initially, the study examined individual process parameters including pH, H₂O₂ concentration, Fe²⁺/H₂O₂ ratio, and inlet pressure to determine their optimal values for maximum dye degradation. The highest degradation of the dye, reaching 68.9%, was achieved with an H₂O₂ concentration of 11.47 × 10^–3 mol. L⁻¹ at pH = 3. Fenton reagent (Fe² + /H₂O₂) achieved a degradation rate of 85.90% at a molar ratio of 1:30. Inlet pressure was found to significantly affect the HC-based method, with maximum degradation observed at 5 bar and pH = 3, resulting in a degradation efficiency of 76.48% over 90 min. Subsequent experiments with HC/ H₂O₂ and HC/Fenton conducted at 5 bar pressure and pH 3 revealed maximum degradation rates of 97.6% in 120 min and complete decolorization within 1 min for HC/Fenton. HC/Fenton also demonstrated the highest reduction in chemical oxygen demand (COD) at 76.43%. Kinetic analysis indicated that the degradation followed pseudo-first-order kinetics for all methods, with the HC/Fenton process exhibiting the fastest rate constant of 2.99 × 10^–2 min⁻¹. Additionally, the electrical energy efficiency of HC-based methods was evaluated and compared. The study suggests that the HC/Fenton process shows promise for efficiently treating dye-contaminated water.

This research delves into developing an efficient screening process for selecting an economical methodology, appropriate catalyst loading, and batch size for reactor occupancy in hydrogenation of 3-nitro-9-ethylcarbazole (NC-3). The main objective was to prepare the 3-Amino-9-ethylcarbazole (AC-3) using a Raney nickel heterogeneous catalyst from NC-3 and to minimize reaction time. The mass transfer coefficient (k_L.a) was estimated, and the effects of agitation and occupancy (based on the change in hydrogen gas pressure) on k_L.a were investigated. The primary focus was to effectively assess optimizing process parameters like hydrogenation pressure (range of 3–10 bar) and temperatures (up to 135 °C) in the presence of Raney nickel catalyst (of loading range from 3.5 to 12%). The reaction methodology is described based on hydrogen uptake concerning the theoretical requirements and process optimized for a Raney nickel loading of 5.4% at a temperature of 130 °C and 7 bar pressure in approximately 4–6 h. Findings revealed that the major hurdle is the limitation of the surface-aerated hydrogenation technique due to the constraint of the laboratory reactor.

Triplochiton scleroxylon, commonly known as Ayous, is a tropical non-edible biomass that generates many residues when exploited. These residues have added value when the different lignocellulosic components, cellulose, hemicellulose, and lignin, are separated. This work aims to determine the optimal conditions for microwave-assisted extraction (MAE) of cellulose and hemicellulose biopolymers from Ayous sawdust. The one-factor-at-a-time methodology was used to establish the ranges for the principal factors affecting microwave-assisted extraction, namely microwave power (W), irradiation time (min), and NaOH concentration (%). Subsequently, response surface methodology, specifically central composite design, was employed to determine the optimal extraction conditions for the biopolymer’s cellulose and hemicellulose. The biopolymers obtained under these optimal conditions were then characterized using infrared spectroscopy. The results indicated that, after factor screening, the experimental domains were microwave power 500–600 W, irradiation time 30–40 min, and NaOH concentration 20–30%. Optimal conditions were found to be 466 W of power, 39 min of irradiation, and 33% NaOH concentration, which resulted in extraction yields of 88% for cellulose. Optimum extraction conditions for hemicellulose (75%) are identical to those for cellulose but with a shorter irradiation time of 26 min. Infrared analysis of biopolymers obtained under initial conditions revealed functional groups characteristic of synthetic biopolymers. In conclusion, the study provides a robust methodology for optimizing MAE processes, offering valuable insights for the efficient recovery of high-quality biopolymers from lignocellulosic biomass.

The bioactive potential of Jeju-Baek-Seohyang (JBS), scientifically known as Daphne jejudoensis M. Kim, was extensively investigated. The antioxidant activity of JBS was relatively lower compared to ascorbic acid in the DPPH and ABTS⁺ assays. Despite this, JBS exhibited significant anti-inflammatory effects in lipopolysaccharide-stimulated RAW 264.7 cells showing an IC₅₀ value of 187.0 µg mL⁻¹, which was relatively lower than that of the Centella asiatica sample (77.0 µg mL⁻¹). Furthermore, the JBS sample evaluated in the cytotoxicity assay showed more than 100% RAW 264.7 cell viability even at 250 ppm, a higher concentration than the C. asiatica sample. To characterize the phytochemicals responsible for these bioactivities, LC-ESI/MS and HPLC analyses were employed wherein daphnetin 7-O-glucoside (57.5 mg g⁻¹) and daphnetin (6.5 mg g⁻¹) were identified as the primary flavonoids in the extracts. This study contributes to the evaluation of the potential of JBS, a recently reclassified species that remains understudied, as a valuable medicinal and industrial substance. Further studies are proposed to fully characterize the medicinal properties of this plant.

On a global basis, the utilization of metallic nanoparticles for improving residual oil recovery has grown dramatically, and nanofluids are widely used in hydrocarbons containing reservoirs to promote the recovery of hydrocarbons. An experimental study was conducted at nominal salinity (NaCl 2.0 wt%) to examine the significance with the addition of magnesium oxide (MgO) and titanium dioxide (TiO₂) with Pure bore produced nanofluid to improve the recovery of oil that was further validated with statistical analysis. The experimental study used particle size analysis in conjunction with TDS, pH, EDX, FTIR, and XRD of MgO and TiO₂ to completely comprehend the nanofluid. To get insight into structure, the microstructure of MgO, TiO₂, and nanofluid was examined. The effect of Pure bore concentration (0.10–0.50wt%) with MgO and TiO₂ concentrations (0.05–0.40wt%) in brine solution (NaCl 2.0wt%) with Pure bore. Analysis of the stability of the nanofluid was aided by the microscopic analysis and validated with statistical analysis using CCD. Additionally, the outcome of pH, viscosity, and salt was investigated. The optimum concentrations of the nanofluid MgO 0.10 wt%, TiO₂ 0.10 wt%, and Pure bore 0.40 wt% were attained at low–medium-salinity conditions (NaCl 2.0 wt%). Its suitability for use in minimal–moderate reservoirs was further validated through 2D contour map, interaction plot, and surface plot with CCD in MINITAB software. It can be noted that nanofluid prepared with Pure bore (0.40 wt%) with TiO₂ (0.10 wt%) marks better results and can be applied in low-salinity (NaCl 2.0 wt%) reservoirs to improve oil recovery.

Thrombosis poses a significant global health challenge due to its life-threatening complications. While traditional antithrombotic drugs like clopidogrel and warfarin are effective, they carry risks such as bleeding. This study uses computational techniques to explore natural compounds as safer alternatives, including ADMET analysis, molecular docking, 100-ns molecular dynamics simulations, and binding energy assessments via MM-PBSA and MM-GBSA methods. Human transglutaminase 2, an enzyme crucial to clot formation, served as the target protein. The selected 48 ligands underwent pharmacokinetic and physicochemical evaluations using SwissADME and pkCSM tools. Among these, 45 adhered to Lipinski’s rule of five, demonstrating favorable drug-like properties and promising ADMET profiles, including high intestinal absorption and blood–brain barrier penetration. Molecular docking identified robust interactions between TG2’s active site residues (TRP 241, TRP 332, and CYS 277) and two standout ligands, oleanolic acid, and ursolic acid lactone, with binding affinities of − 9 kcal/mol and − 9.4 kcal/mol, respectively, surpassing reference drugs. Extended MD simulations confirmed the stability of the ligand–protein complexes, with RMSD and RMSF analyses indicating minimal fluctuations in active site residues. MM-PBSA and MM-GBSA energy calculations revealed significant contributions from electrostatic and van der Waals interactions, supporting the observed binding stability. This study underscores the potential of oleanolic acid and ursolic acid lactone as promising antithrombotic agents. Their favorable pharmacokinetics and stable interactions with TG2 highlight their potential for developing safer, target-specific antithrombotic therapies.

Graphical abstract