Search Results (517)

Over efficient photocatalysts, CO₂ photoreduction typically converts CO₂ into low-carbon chemicals, which serve as raw materials for downstream synthesis processes. Here, an efficient composite photocatalyst heterojunction (Cu₂O-u/g-C₃N₄) has been fabricated to reduce CO₂. Graphitic carbon nitride (g-C₃N₄) was synthesized via thermal polymerization of urea at 550 °C, while pre-dispersed Cu₂O derived from urea pyrolysis (Cu₂O-u) was prepared by thermal reduction of urea and CuCl₂·2H₂O at 180 °C. The heterojunction Cu₂O-u/g-C₃N₄ was subsequently constructed through hydrothermal treatment at 180 °C. This heterojunction exhibited a bandgap of 2.10 eV, with dual optical absorption edges at 485 nm and above 800 nm, enabling efficient harvesting of solar light. Under 175 W mercury lamp irradiation, the heterojunction catalyzed liquid-phase CO₂ photoreduction to formic acid, acetic acid, and methanol. Its formic acid production activity surpassed that of pristine g-C₃N₄ by 3.14-fold and TiO₂ by 8.72-fold. Reaction media, hole scavengers, and reaction duration modulated product selectivity. In acetonitrile/isopropanol systems, formic acid and acetic acid production reached 579.4 and 582.8 μmol·h⁻¹·g_cat⁻¹. Conversely, in water/triethanolamine systems, methanol production reached 3061.6 μmol·h⁻¹·g_cat⁻¹, with 94.79% of the initial conversion retained after three cycles. Finally, this work ends with the conclusions of the CO₂ photocatalytic reduction to formic acid, acetic acid, and methanol, and recommends prospects for future research. Full article

Background/Objectives: PEGylated liposomes are widely recognized for their biocompatibility and capacity to extend systemic circulation via “stealth” properties. However, the PEG corona often limits tumor penetration and cellular internalization. Targeting matrix metalloproteinase-2 (MMP-2), frequently upregulated in breast cancer stroma, presents an opportunity to enhance tissue-specific drug delivery. In this study, we engineered MMP-2-responsive GPLGVRG peptide-modified cleavable PEGylated liposomes for targeted paclitaxel (PTX) delivery. Methods: Molecular docking simulations employed the MMP-2 crystal structure (PDB ID: 7XJO) to assess GPLGVRG peptide binding affinity. A cleavable, enzyme-sensitive peptide-PEG conjugate (Chol-PEG_2K-GPLGVRG-PEG_5K) was synthesized via small-molecule liquid-phase synthesis and characterized by ¹H NMR and MALDI-TOF MS. Liposomes incorporating this conjugate (S-Peps-PEG_5K) were formulated to evaluate whether MMP-2-mediated peptide degradation triggers detachment of long-chain PEG moieties, thereby enhancing internalization by 4T1 breast cancer cells. Additionally, the effects of tumor microenvironmental pH (~6.5) and MMP-2 concentration on drug release dynamics were investigated. Results: Molecular docking revealed robust GPLGVRG-MMP-2 interactions, yielding a binding energy of −7.1 kcal/mol. The peptide formed hydrogen bonds with MMP-2 residues Tyr A:23 and Arg A:53 (bond lengths: 2.4–2.5 Å) and engaged in hydrophobic contacts, confirming MMP-2 as the primary recognition site. Formulations containing 5 mol% Chol-PEG_2K-GPLGVRG-PEG_5K combined with 0.15 µg/mL MMP-2 (S-Peps-PEG_5K +MMP) exhibited superior internalization efficiency and significantly reduced clonogenic survival compared to controls. Notably, acidic pH (~6.5) induced MMP-2-mediated cleavage of the GPLGVRG peptide, accelerating S-Peps-PEG_5K dissociation and facilitating drug release. Conclusions: MMP-2-responsive, cleavable PEGylated liposomes markedly improve PTX accumulation and controlled release at tumor sites by dynamically modulating their stealth properties, offering a promising strategy to enhance chemotherapy efficacy in breast cancer. Full article

The mechanism for the upscale deposition of energy into the atmosphere from molecules and photons up to organized wind systems is examined. This analysis rests on the statistical multifractal analysis of airborne observations. The results show that the persistence of molecular velocity after collision in breaking the continuous translational symmetry of an equilibrated gas is causative. The symmetry breaking may be caused by excited photofragments with the associated persistence of molecular velocity after collision, interaction with condensed phase surfaces (solid or liquid), or, in a scaling environment, an adjacent scale having a different velocity and temperature. The relationship of these factors for the solution to the Navier–Stokes equation in an atmospheric context is considered. The scale invariant version of Gibbs free energy, carried by the most energetic molecules, enables the acceleration of organized flow (winds) from the smallest planetary scales by virtue of the nonlinearity of the mechanism, subject to dissipation by the more numerous average molecules maintaining an operational temperature via infrared radiation to the cold sink of space. The fastest moving molecules also affect the transfer of infrared radiation because their higher kinetic energy and the associated more-energetic collisions contribute more to the far wings of the spectral lines, where the collisional displacement from the central energy level gap is greatest and the lines are less self-absorbed. The relationship of events at these scales to macroscopic variables such as the thermal wind equation and its components will be considered in the Discussion section. An attempt is made to synthesize the mechanisms by which winds are generated and sustained, on all scales, by appealing to published works since 2003. This synthesis produces a view of the general circulation that includes thermodynamics and the defining role of turbulence in driving it. Full article

Inorganic nanoparticles (NPs) have been synthesised via mixing and coalescence of droplets containing precursors and entrained by gaseous streams. The droplets have been generated by ultrasonic aerosolisation of two different liquid phases, each containing the respective reagent. The as-produced NPs are trapped by mixing with a liquid phase in a Venturi nozzle, acting simultaneously as a collector and concentrator of the solid nanosized phase produced. Commercial electrically powered ultrasonic aerosolising devices have been adapted to atomise salt solutions characterised by high electrical conductivity. This process allowed the synthesis of calcium carbonate NPs with an average diameter in the range of (34–52) nm, according to the concentration of precursors in the aerosolised phases. This closed-loop method of synthesis, where neither capping agents were used nor demanding operating conditions were adopted, can represent a safe and viable eco-friendly technique for NP production free of undesirable compounds, as required for pharmaceutical preparations and theranostic uses. Full article

In the chemistry of bio-based furans, the Diels–Alder reaction plays an important role as a renewable route for the synthesis of fuels, fine chemicals, and monomers. Nonetheless, the unfavorable kinetic and thermodynamic parameters inherent to the Diels–Alder reaction involving furans as dienes often lead to the reversibility of cycloaddition, resulting in decreased equilibrium conversion and diastereoselectivity. In this study, we present a new strategy for overcoming the problem of reversibility in chemical reactions. We demonstrate that conducting the reaction under solvent-free conditions can facilitate the transition from a molten state formed by the initial reactants to a solid phase containing the reaction product along with an excess of the initial substrate. According to our results, such a liquid-to-solid transition of the reaction mixture can lead to exceptionally high conversion and diastereoselectivity in the furan–maleimide Diels–Alder reaction, particularly for challenging electron-poor furanic substrates. Our approach enables the reversible furan–maleimide Diels–Alder reaction to be performed in a cleaner and more environmentally friendly manner, free from the complexities associated with the use of solvents and the need for purification from side products. Full article

Millimeter-wave (mmWave) antennas and antenna arrays have gained significant attention due to their pivotal role in emerging wireless communication, sensing, and imaging technologies. With the rapid deployment of 5G and the transition toward 6G networks, the demand for compact, high-gain, and reconfigurable mmWave antennas has intensified. This article highlights recent advancements in mmWave antenna technologies, including hybrid beamforming using phased arrays, dynamic beam-steering enabled by liquid crystal and MEMS-based structures, and high-capacity MIMO architectures. We also examine the integration of metamaterials and metasurfaces for miniaturization and gain enhancement. Applications covered include wearable antennas with low-SAR textile substrates, conformal antennas for UAV-based mmWave relays, and high-resolution radar arrays for autonomous vehicles. The study further analyzes innovative fabrication methods such as inkjet and aerosol jet printing, micromachining, and laser direct structuring, along with advanced materials like Kapton, PDMS, and graphene. Numerical modeling techniques such as full-wave EM simulation and machine learning-based optimization are discussed alongside experimental validation approaches. Beyond communications, we assess mmWave systems for biomedical imaging, security screening, and industrial sensing. Key challenges addressed include efficiency degradation at high frequencies, interference mitigation in dense environments, and system-level integration. Finally, future directions, including AI-driven design automation, intelligent reconfigurable surfaces, and integration with quantum and terahertz technologies, are outlined. This comprehensive synthesis aims to serve as a valuable reference for advancing next-generation mmWave antenna systems. Full article

Poly(acrylonitrile-butadiene-styrene) (ABS) is a common polymer used in toys, automobile parts, and membranes. Membranes fabricated with this copolymer commonly employ toxic solvents and have a dense architecture, which may not work in all applications. This work investigates the synthesis of ABS membranes, using green solvents and the influence of additives on the phase inversion process during the non-solvent-induced phase separation. The addition of water-soluble additives, ethanol, and acetone is hypothesized to provide additional control over viscosity and volatility, and, consequently, impact the phase inversion process. Membranes were fabricated with PolarClean and with various additive concentrations and evaporation times. The resulting membranes were characterized using scanning electron microscopy (SEM) and a pycnometer to visualize the pore structure and obtain porosity information. Membrane performance, including water flux and bovine serum albumin rejection, was evaluated using dead-end cell filtration. Membranes fabricated using only PolarClean had fingerlike pore morphology and relatively low protein rejection. The addition of additives resulted in a change in pore architecture and rejection, which is hypothesized to be a result of additives’ volatility, humidity, and destabilization of liquid–liquid separation. This study provides a more detailed understanding of the impact of additives on the resulting ABS membrane structure and performance, with a focus on safer solvents. Full article

Rapid mixing is widely prevalent in the field of microfluidics, encompassing applications such as biomedical diagnostics, drug delivery, chemical synthesis, and enzyme reactions. Mixing efficiency profoundly impacts the overall performance of these devices. However, at the micro-scale, the flow typically presents as laminar flow due to low Reynolds numbers, rendering rapid mixing challenging. Leveraging the vortices within a droplet of the Taylor flow and inducing chaotic convection within the droplet through serpentine channels can significantly enhance mixing efficiency. Based on this premise, we have developed a droplet micromixer that integrates the T-shaped channels required for generating Taylor flow and the serpentine channels required for inducing chaotic convection within the droplet. We determined the range of inlet liquid flow rate and gas pressure required to generate Taylor flow and conducted experimental investigations to examine the influence of the inlet conditions on droplet length, total flow rate, and mixing efficiency. Under conditions where channel dimensions and liquid flow rates are identical, Taylor flow achieves a nine-fold improvement in mixing efficiency compared to single-phase flow. At low Reynolds number (0.57 ≤ Re ≤ 1.05), the chip can achieve a 95% mixing efficiency within a 2 cm distance in just 0.5–0.8 s. The mixer proposed in this study offers the advantages of simplicity in manufacturing and ease of integration. It can be readily integrated into Lab-on-a-Chip devices to perform critical functions, including microfluidic switches, formation of nanocomposites, synthesis of oxides and adducts, velocity measurement, and supercritical fluid fractionation. Full article

Proton exchange membrane fuel cells (PEMFCs) have been widely studied as an efficient and environmentally friendly energy conversion technology in recent years. However, the high cost, easy poisoning and complex synthesis methods of noble metal catalysts have hindered their commercialization. Therefore, in this paper, a non-noble metal composite catalyst CuFeCo/C for the oxygen reduction reaction (ORR) was prepared by using a facile liquid-phase reduction method. The ORR kinetic performance of CuFeCo/C was evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and rotating ring-disk electrode (RRDE) tests. The results show that the oxygen reduction peak of CuFeCo/C appears at about 0.64 V, the half-wave potential is about 0.73 V, the limiting current density is about −16.51 A·m⁻², and the Tafel slope is about −0.08. The 10,800 s chronoamperometry test shows that the catalyst has a very good long-term cycle stability. This indicates that the CuFeCo/C composite catalyst has strong stability, good conductivity and ORR catalytic activity under alkaline conditions, which can promote the large-scale commercial application of PEMFCs. Full article

The widespread implementation of anaerobic digestion (AD) systems for organic waste treatment is increasingly challenged by emerging contaminants, including microplastics (MPs), antibiotics, and heavy metals (HMs), which exhibit environmental persistence and pose risks to ecological and human health. This review critically examines the sources, transformation pathways, and advanced mitigation strategies for these contaminants within AD systems. MPs, primarily derived from fragmented plastics and personal care products, accumulate in digestates and act as vectors for adsorbing toxic additives and pathogens. Antibiotics, introduced via livestock manure and wastewater, exert selective pressures that propagate antibiotic resistance genes (ARGs) while disrupting methanogenic consortia. HMs, originating from industrial and agricultural activities, impair microbial activity through bioaccumulation and enzymatic interference, with their bioavailability modulated by speciation shifts during digestion. To combat these challenges, promising mitigation approaches include the following: (1) bioaugmentation with specialized microbial consortia to enhance contaminant degradation and stabilize HMs; (2) thermal hydrolysis pretreatment to break down MPs and antibiotic residues; (3) chemical passivation using biochar or sulfides to immobilize HMs. Co-digestion practices inadvertently concentrate these contaminants, with MPs and HMs predominantly partitioning into solid phases, while antibiotics persist in both liquid and solid fractions. These findings highlight the urgency of optimizing mitigation strategies to minimize contaminant mobility and toxicity. However, critical knowledge gaps persist regarding the long-term impacts of biodegradable MPs, antibiotic transformation byproducts, and standardized regulatory thresholds for contaminant residues in digestate. This synthesis underscores the necessity for integrated engineering solutions and policy frameworks to ensure the safe resource recovery from AD systems, balancing energy production with environmental sustainability. Full article

Dispersive liquid–liquid microextraction (DLLME) is an economical, rapid, sensitive, and environmentally friendly miniaturized liquid–liquid extraction format. It has been successfully applied in trace element analysis since 2006 when it was first proposed. This article describes a new dispersive liquid–liquid microextraction method for the determination of trace amounts of Co²⁺. In brief, this method involves the extraction of Co²⁺ from the sample to the trichloromethane phase by the dispersive action of methanol after the formation of a complex with a novel 9-(methylaminomethyl)anthracene-Ni(II) phthalocyanine (MAMA Ni(II)Pc 2) as a sensor. The first step in this study was the synthesis and characterisation of the sensor. Later, the proposed method was optimized with respect to various parameters such as extraction and dispersive solvents and their amounts, pH, sensor concentration, and centrifugation time and rate. The calibration graph was linear between 0.40 and 260 µg/L, with an R² of 0.9978. The limit of detection and limit of quantification were found to be 0.19 µg/L and 0.46 µg/L, respectively. To evaluate the precision of this method, the analysis of a 50 µg/L Co²⁺ solution was carried out. The intra-day and inter-day relative standard deviation values were calculated as 1.7% and 2.4%, respectively (n = 7). The accuracy of the proposed method was investigated by means of a standard addition/recovery test. Full article

Cholesterol plays an essential role in biological membranes and is crucial for maintaining their stability and functionality. In addition to biological membranes, cholesterol is also used in various synthetic lipid-based structures such as liposomes, proteoliposomes, and nanodiscs. Cholesterol regulates membrane properties by influencing the density of lipids, phase separation into liquid-ordered (Lo) and liquid-disordered (Ld) areas, and stability of protein–membrane interactions. For planar bilayers, cholesterol thickens the membrane, decreases permeability, and brings lipids into well-ordered domains, thereby increasing membrane rigidity by condensing lipid packing, while maintaining lateral lipid mobility in disordered regions to preserve overall membrane fluidity. It modulates membrane curvature in curved bilayers and vesicles, and stabilizes low-curvature regions, which are important for structural integrity. In liposomes, cholesterol facilitates drug encapsulation and release by controlling bilayer flexibility and stability. In nanodiscs, cholesterol enhances structural integrity and protein compatibility, which enables the investigation of protein–lipid interactions under physiological conditions. In proteoliposomes, cholesterol regulates the conformational stability of embedded proteins that have implications for protein–lipid interaction. Developments in molecular dynamics (MD) techniques, from coarse-grained to all-atom simulations, have shown how cholesterol modulates lipid tail ordering, membrane curvature, and flip-flop behavior in response to concentration. Such simulations provide insights into the mechanisms underlying membrane-associated diseases, aiding in the design of efficient drug delivery systems. In this review, we combine results from MD simulations to provide a synoptic explanation of cholesterol’s complex function in regulating membrane behavior. This synthesis combines fundamental biophysical information with practical membrane engineering, underscoring cholesterol’s important role in membrane structure, dynamics, and performance, and paving the way for rational design of stable and functional lipid-based systems to be used in medicine. In this review, we gather evidence from MD simulations to provide an overview of cholesterol’s complex function regulating membrane behavior. This synthesis connects the fundamental biophysical science with practical membrane engineering, which highlights cholesterol’s important role in membrane structure, dynamics, and function and helps us rationally design stable and functional lipid-based systems for therapeutic purposes. Full article

Background: Including Chronic Myeloid Leukemia (CML) patients with deep molecular responses (MR4.5) and those with suboptimal responses provides valuable insights into treatment-associated metabolic changes. This study aimed to characterize the metabolomic alterations associated with CML and identify potential biomarkers for treatment response, particularly in patients achieving a deeper molecular response versus those with poorer responses. Methods: Plasma samples were collected from 51 chronic-phase CML patients and 24 healthy controls. CML patients were classified into two groups based on molecular responses: T1 (BCR-ABL1 IS ≤ 0.0032%) and T2 (BCR-ABL1 IS > 0.0032%, <1%). Metabolomic profiling was conducted using quadrupole time-of-flight liquid chromatography/mass spectrometry. The data analysis involved a partial least squares discriminant analysis, variable importance in projection (VIP) scores, and a pathway enrichment analysis. Significant metabolites were identified. Results: The PLS-DA revealed distinct metabolomic profiles between CML patients and healthy controls as well as between the T1 and T2 groups. Key differentiating metabolites with VIP scores > 1.5 included glutamate, hypoxanthine, and D-galactonic acid. In the T2 group, significant increases in malate and 5-aminoimidazole-4-carboxamide ribonucleotide were observed, reflecting disruptions in purine metabolism, the tricarboxylic acid cycle, and amino acid metabolism. The pathway enrichment analysis highlighted significant alterations in CML energy metabolism, nucleotide synthesis, and amino acid biosynthesis. Conclusions: CML patients exhibit pronounced metabolic changes, particularly in energy and nucleotide metabolism, which are linked to treatment response. These findings provide novel insights into CML biology and suggest potential biomarkers for monitoring treatment efficacy and predicting outcomes and therapeutic targets for improving treatment outcomes and overcoming tyrosine kinase inhibitor resistance. Full article

Galaxamide, an N-methylated cyclo-pentapeptide containing five D-leucines isolated from Galaxaura filamentosa, has shown significant antitumor activity. This unique cyclo-pentapeptide offered a fresh skeleton for structural modifications. Herein, galaxamide and its 23 analogs (Gala01~Gala24) were designed and synthesized by substituting D-leucine with various proteinogenic amino acids or altering the amino acid configuration using the “3 + 2” strategy, and the in vitro antitumor activity of these cyclopeptides was studied utilizing the CCK-8 assay against two human tumor cell lines (A549 and K562) and one human normal cell line (293T). The total yields of galaxamide and its analogs reached 9.7% and 9.1–16.0%, respectively. CCK-8 assays demonstrated that these compounds showed broad-spectrum antitumor activity, with Gala04 exhibiting outstanding activity against K562 cells (IC₅₀ = 4.2 µM). The anticancer efficacy of galaxamide analogs against tumor cell lines was significantly influenced by the quantity of D-leucines and the D-leucine position. Full article

The gas-liquid sulfonation of α-olefin sulfonate (AOS) in falling film reactors faces significant limitations, primarily due to poor mass transfer efficiency and excessive byproduct formation. To overcome these challenges, a novel cross-shaped microchannel reactor was developed for the continuous gas-liquid sulfonation of α-olefin (AO) with gaseous sulfur trioxide (SO₃). The influence of key process parameters, including gas-phase flow rate, reaction temperature, SO₃/AO molar ratio, and SO₃ volume fraction, on product characteristics and their interactions was systematically investigated using the single-factor experiment and response surface methodology (RSM). A high-precision empirical model (coefficient of determination, R² = 0.9882) to predict product content was successfully constructed. To achieve multi-objective optimization considering product active substance content and energy efficiency, a strategy combining a two-population genetic algorithm with the entropy-weighted TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) method was implemented. Optimal conditions were determined as follows: gas-phase flow rate of 228 mL/min, reaction temperature of 52 °C, SO₃/AO molar ratio of 1.27, and SO₃ volume fraction of 4%. Compared to conditions optimized solely by RSM, this multi-objective approach achieved a significant 10% reduction in energy efficiency, with only a marginal 3.8% decrease in active substance content. This study demonstrates the feasibility and advantages of microreactors for the efficient and green synthesis of AOS. Full article