Search Results (2,112)

In this paper, we investigated the efficient metal-free phosphorus–nitrogen (PN) catalyst and used the PN catalyst to degrade waste PU with two-component binary mixed alcohols as the alcohol solvent. We examined the effects of reaction temperature, time, and other factors on the hydroxyl value and viscosity of the degradation products; focused on the changing rules of the hydroxyl value, viscosity, and molecular weight of polyols recovered from degradation products with different dosages of the metal-free PN catalyst; and determined the optimal experimental conditions of reaction temperature 180 °C, reaction time 3 h, and PN dosage 0.08%. The optimal experimental conditions were 180 °C, 3 h reaction time, and 0.08% PN dosage, the obtained polyol viscosity was 3716 mPa·s, the hydroxyl value was 409.2 mgKOH/g, and the number average molecular weight was 2616. The FTIR, ¹H, NMR, and other tests showed that the waste urethanes were degraded into oligomers successfully, the recycled polyether polyols were obtained, and a series of recycled polyurethanes with different substitution ratios were then prepared. A series of recycled polyurethane materials with different substitution rates were then prepared and characterized by FTIR, SEM, compression strength, and thermal conductivity tests, which showed that the recycled polyurethane foams had good physical properties such as compression strength and apparent density, and the SEM test at a 20% substitution rate showed that the recycled polyol helped to improve the structure of the blisters. Full article

This study investigates the thermoelectric properties of Se-rich β-Ag₂Se synthesized via a mechanochemical method followed by spark plasma sintering (SPS) in less than 30 min of the total reaction time. Importantly, only a short 10 min milling process followed by appropriate SPS was enough to produce single-phase Ag₂Se_1+x samples with varying selenium content (where x = 0, 0.01, 0.02, 0.04). The introduction of excess selenium significantly influenced the thermoelectric performance, optimizing the carrier concentration during synthesis and resulting in substantial thermoelectric improvements. The sample with nominal composition Ag₂Se_1.01 exhibited a high dimensionless figure-of-merit (ZT) >0.9 at 385 K, which is nearly six times higher than the reference sample (β-Ag₂Se). Our findings bring valuable insight into the technology of optimization of thermoelectric characteristics of Se-rich β-Ag₂Se, highlighting its potential for applications in thermoelectric devices. The study demonstrates the energetically efficient and environmental advantage of our mechanochemical route to produce Se-rich β-Ag₂Se, providing a solvent-free and commercially viable alternative synthesis for energy (thermoelectric and solar energy). Full article

Improving the low-temperature performance of lithium-ion batteries is critical for their widespread adoption in cold environments. In this study, we designed a novel LHCE featuring a solvent polarity gradient, designed to maximize both room- and low-temperature ion mobility. Extremely polar fluoroethylene carbonate (FEC) and low-freezing-point, −135 °C, non-polar nonaflurobutyl methyl ether (NONA) were supplemented by two intermediate solvents with incremental step-downs in polarity. The intermediate solvents consist of methyl (2,2,2-triflooethyl) carbonate (FEMC) and either diethylene carbonate (DEC), ethyl methyl carbonate (EMC), or dibutyl carbonate (DBC). The four solvents were combined with 1 M lithium bis(fluorosulfonyl)amide (LiFSI) salt and were able to accommodate 37.5% diluent volume, resulting in ultra-low electrolyte freezing points below −120 °C. This contrasts with our previously investigated three-solvent LHCE, which only allowed for a 14% diluent volume and a −85 °C freezing point. Localized high salt concentrations were shown by less than 3% of FSI- anions being free in solution. The gradient LHCEs also showed room-temperature ionic conductivities above 10–3 S/cm and maintained high ion mobility below −40 °C. Lithium metal coin cells with LiFePO4 (LFP) cathodes featuring the gradient LHCEs, a reference three-solvent LHCE, and commercial (1 M LiPF6 in 1:1 EC:DEC) electrolyte were constructed. All gradient LHCEs outperformed both the three-solvent and commercial electrolytes at all temperatures, with the DEC-based gradient LHCE showing the best performance of 159.7 mAh/g at 25 °C and 109.2 mAh/g at −50 °C, corresponding to a 68% capacity retention. These findings highlight the potential of LHCE systems to improve battery performance in low-temperature environments and propose a new gradient design strategy for electrolytes to yield advantages of both polar and weakly polar solvents. Full article

In this study, the use of surfactant-free water-in-oil gelled emulsions containing benzyl alcohol (BAl/w) is proposed as an alternative to the more traditional use of organic solvents for removing varnishes. To mitigate the strong swelling and solvent action of benzyl alcohol and protect the paint and the underlying layers, temporary hydrophobization with cyclomethicone D5 has been proposed. The aim of this study was to evaluate the application of BAl/w surfactant-free, constructed with three different gelling agents of the aqueous dispersing phase (xanthan gum, agar-agar, and polyacrylate) on the surface of an oil painting varnished with and without preliminary saturation with D5. The role of pH, which can influence the ionization, and therefore the water solubility of terpene molecules and all other acid species present on the surface, was also studied. Fourier transform infrared (FT-IR) and Raman spectroscopies were used to characterize the pigments and the surface before and after varnish removal. Elemental analysis and any morphological changes were evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The leaching efficiency of each surfactant-free emulsion applied on the paint surface was evaluated using a gas chromatography/mass spectroscopy (GC/MS) analysis: the fatty acid content was established in each sample before and after the treatments. Full article

An imbalance in the body’s pH or temperature may modify the immune response and result in ailments such as autoimmune disorders, infectious diseases, cancer, or diabetes. Dual pH- and thermo-responsive carriers are being evaluated as advanced drug delivery microdevices designed to release pharmaceuticals in response to external or internal stimuli. A novel drug delivery system formulated as hydrogel was developed by combining a pH-sensitive polymer (the “biosensor”) with a thermosensitive polymer (the delivery component). Thus, the hydrogel was created by cross-linking, using a solvent-free thermal approach, of poly(N-isopropylacrylamide-co-N-hydroyethyl acrylamide), P(NIPAAm-co-HEAAm), and poly(methylvinylether-alt-maleic acid), P(MVE/MA). The chemical structure of the polymers and hydrogels was analyzed using Fourier-transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopies. The pH/thermosensitive hydrogel loses its thermosensitivity under physiological conditions but, remarkably, can recover the thermosensitive capabilities when certain physiologically active biomolecules, acting as triggering agents, electrostatically interact with pH-sensitive units. Our research aimed to develop a drug delivery system that could identify the disturbance of normal physiological parameters and instantaneously send a signal to thermosensitive units, which would collapse and modulate the release profiles of the drug. Full article

Triboelectric separation, a solvent-free method, was investigated as a tool for protein enrichment in wheat flour. Gluten–starch model mixtures, flour, and reground flour fractions were evaluated for their separation characteristics (selectivity and efficiency). Mass yield, protein content, particle size distribution, and SEM analysis were used to assess performance. Selectivity and efficiency increased with gluten concentration, peaking at 63% for the 50% gluten mixture, but declined at higher concentrations. The 15% gluten benchmark demonstrated effective protein separation, with protein enrichment occurring in the ground electrode fraction and a corresponding depletion in the positive electrode fraction. In contrast, flour and reground flour fractions exhibited reduced separation efficiency, showing protein depletion in both electrode fractions due to agglomeration. The benchmark achieved the highest separation efficiency (47%), followed by reground flour (41%) and flour (7%). Finer particles in reground flour enhanced chargeability and GE deposition, while larger agglomerates in flour reduced efficiency, leading to material accumulation in the cups. Pre-milling helped detach protein and starch to some extent but also triggered re-agglomeration. Larger particles were influenced more by gravitational forces. These findings highlight the complexity of wheat flour fractionation and the need to optimize particle size and charge distribution to improve protein enrichment through triboelectric separation. Full article

Cyclen-based ligands are prominent tools for transferring radioisotopes through the human body. A crucial criterion is the stability of their complexes, which is partly determined by the stabilization of the free ligand in solution. For the assessment of the later property, the favored conformation(s) in the solution must be known. In the present study, the conformational space of four neutral cyclen-based ligands was elucidated by a multi-step procedure: the survey of the conformational space using molecular mechanics (MM) was followed by Density Functional Theory (DFT) calculations on the low-energy conformers and evaluation of the solvent effects. The results revealed several low-energy conformers in aqueous solution. In terms of electronic energies, a significant preference of symmetric structures (C₄ or C₂—similar to the ligand arrangements in their metal complexes) was obtained. The thermal contributions to the Gibbs free energy (mainly the vibrational ones) tend to decrease this preference by several kJ/mol against non-symmetric structures. Nonetheless, the advantage of compact symmetric structures was confirmed in all the four studied cases. Full article

The SARS-CoV-2 main protease (Mpro, also known as 3CLpro) is a key target for antiviral therapy due to its critical role in viral replication and maturation. This study investigated the inhibitory effects of Bofutrelvir, Nirmatrelvir, and Selinexor on 3CLpro through molecular docking, molecular dynamics (MD) simulations, and free energy calculations. Nirmatrelvir exhibited the strongest binding affinity across docking tools (AutoDock Vina: −8.3 kcal/mol; DiffDock: −7.75 kcal/mol; DynamicBound: 7.59 to 7.89 kcal/mol), outperforming Selinexor and Bofutrelvir. Triplicate 300 ns MD simulations revealed that the Nirmatrelvir-3CLpro complex displayed high conformational stability, reduced root mean square deviation (RMSD), and a modest decrease in solvent-accessible surface area (SASA), indicating enhanced structural rigidity. Gibbs free energy analysis highlighted greater flexibility in unbound 3CLpro, stabilized by Nirmatrelvir binding, supported by stable hydrogen bonds. MolProphet prediction tools, targeting the Cys145 residue, confirmed that Nirmatrelvir exhibited the strongest binding, forming multiple hydrophobic, hydrogen, and π-stacking interactions with key residues, and had the lowest predicted IC₅₀/EC₅₀ (9.18 × 10⁻⁸ mol/L), indicating its superior potency. Bofutrelvir and Selinexor showed weaker interactions and higher IC₅₀/EC₅₀ values. MM/PBSA analysis calculated a binding free energy of −100.664 ± 0.691 kJ/mol for the Nirmatrelvir-3CLpro complex, further supporting its stability and binding potency. These results underscore Nirmatrelvir’s potential as a promising therapeutic agent for SARS-CoV-2 and provide novel insights into dynamic stabilizing interactions through AI-based docking and long-term MD simulations. Full article

Calcium and barium carbonates were synthesized via biologically induced mineralization using Bacillus subtilis. The biogenic materials were characterized by using infrared and Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. These biogenic carbonates were then tested as basic heterogenous catalysts for the solvent-free Knoevenagel reaction between 5-HMF derivatives and active methylene compounds, producing 3-(furan-2-yl)acrylonitrile derivatives in 71–87% yields. Optimal catalytic performance was achieved with a 50:50 Ca:Ba ratio, attributed to the synergistic interaction between baritocalcite and vaterite, which enhances the availability of active basic sites and surface interactions. This method offers operational simplicity, reduced reaction times, good yields, excellent (E)-selectivity, and minimal catalyst loading. Full article

Pandan, a tropical crop, is rich in squalene (SQ), known for its antioxidant and hypoglycemic properties, and 2-acetyl-1-pyrroline (2-AP), which imparts a characteristic aroma. This study focuses on the extraction of the two bioactive compounds from Pandan leaves and investigates the effects of drying methods, extraction solvents, and conditions on the yield of SQ and 2-AP. Results show that hot air-dried Pandan leaves when extracted using the binary solvent system of ethanol and n-hexane (EH), yield higher SQ content while maintaining an adequate content of 2-AP. To further optimize the extraction process, a single-factor experiment was followed by optimization using Box–Behnken design (BBD) and response surface methodology (RSM). The optimal extraction conditions were determined as follows: ultrasound time of 60 min, a temperature of 50 °C, power of 300 W, and a solid-to-liquid ratio of 1:5 g/mL. Under these conditions, an SQ yield of 1229.98 ± 13.09 μg/DW 1 g Pandan leaves and a 2-AP yield of 80.72 ± 0.88 μg/DW 1 g Pandan leaves were achieved, representing increases of 3.30% and 9.82% compared to pre-optimization values. Additionally, the antioxidant activities of EH extracts were evaluated through various in vitro assays. The extracts demonstrated significant DPPH and ABTS free radical scavenging activity (12.46 μmol TE/g DW and 22.14 μmol TE/g DW, respectively), along with ferric and cupric ion reducing power (10.629 μmol TE/g DW and 14.275 μmol TE/g DW, respectively). The extracts also exhibited notable inhibitory effects on α-amylase and α-glucosidase. The findings suggest that these extracts are a promising natural source of antioxidants with potential applications in health and nutrition. Full article

Spent coffee grounds, the main by-product of the coffee-brewing process, were valorized as a renewable source of lipids for the synthesis of novel wax esters and as an alternative and sustainable oil-structuring agent for the production of oleogels. The lipase-catalyzed reactions were implemented using fatty alcohols both under solvent-free conditions and with limonene as an environmentally friendly solvent. Wax esters were evaluated for their ability to formulate olive oil oleogels through the determination of the physical properties of oleogels. Results showed that high conversion yields were achieved when cetyl and behenyl alcohols were applied under solvent-free conditions, achieving a maximum yield of 90.3% and 91.7%, respectively. In the presence of limonene, the highest conversion yields were 88.9% and 94.5% upon the use of cetyl and behenyl alcohols, respectively. The behenyl wax esters exhibited greater oil-structuring properties, regardless of whether they were derived from solvent or solvent-free conditions. Rheological curves showed that the produced oleogels exhibited a strong gel strength, which was enhanced as the wax ester concentration increased. Frequency sweep curves confirmed the formation of a stable three-dimensional oleogel network and revealed the low dependence of the storage modulus on frequency. Overall, this study demonstrated that producing wax esters from renewable lipid sources has the potential to serve as an effective circular economy paradigm for creating novel oleogels with a broad range of applications. Full article

The metallocenyl-containing β-diketonato rhodium(I) dicarbonyl complexes of [Rh(FcCOCHCOR)(CO)₂] where R = CF₃, 10; Fc = ferrocenyl = Fe^II(C₅H₅)(C₅H₄), 11; Rc = ruthenocenyl = Ru^II(C₅H₅)(C₅H₄), 12; and Oc = osmocenyl = Os^II(C₅H₅)(C₅H₄), 13 were synthesized. Complexes 10–13 were then subjected to an electrochemical study utilizing cyclic voltammetry (CV), square wave voltammetry (SWV), and linear sweep voltammetry (LSV) in the non-coordinating solvent/supporting electrolyte medium CH₂Cl₂/0.1 mol dm⁻³ [N(ⁿBu)₄][B(C₆F₅)₄]. The formal reduction potential for the electrochemical reversible Fc^0/+ couples in 10–13 was identified in the range 0.156 ≤ E^o′ ≤ 0.328 V while the electrochemically irreversible osmocenyl and ruthenocenyl oxidations were observed at peak anodic potentials of E_pa = 0.640 V and E_pa = 0.751 V, respectively. Resolution between the closely overlapping CV-determined Fc^0/+ and Rh^I/II couples was too poor for unambiguous measurement of the Rh^I/II redox potential, but square wave voltammetry allowed estimates of E^o′ (Rh^I/II) in the range 0.156 ≤ E^o′ ≤ 0.398 V. FT-IR spectroelectrochemistry confirmed the one-electron oxidation of Rh^I by the appearance of CO vibrational bands at stretching frequencies, which are associated with rhodium(II) and not rhodium(III). Cytotoxicity tests on 10 (IC₅₀ = 19.2 µM) showed it to be substantially less cytotoxic than the free β-diketone, FcCOCH₂COCF₃, and [Rh(FcCOCHCOCF₃)(cod)]. Full article

As an environment-friendly biodegradable material, poly (vinyl alcohol) (PVA) has been focused on improving performance and expanding its applications. In this study, improved performance lignin nanoparticle/PVA composite film was prepared by phenolation of bagasse lignin (BL) using a novel ternary deep eutectic solvent (DES). The effects of introduction of DES-phenolated lignin (DL) nanoparticles with different additions (1, 3, 5, 10 wt%) on the properties of DL/PVA composite film were comprehensively studied by mechanical performance test, UV-shielding performance test, contact angle measurement, thermogravimetric analyses and DPPH free radical scavenging activity. The experimental results indicated that lignin nanoparticles (LNPs) were homogeneously distributed in a biodegradable PVA matrix due to hydrogen bonds between the PVA matrix and lignin nanoparticles. With the introduction of DES pretreatment on native bagasse lignin, the various performances of DL/PVA composite films, such as tensile strength, surface hydrophobicity, UV-shielding and thermal stability, were enhanced in comparison with both pure PVA film and BL/PVA composite film incorporated with DES-untreated BL. The tensile strength of DL/PVA composite film with 3 wt% addition increased to 97.79 MPa from 69.41 MPa for pure PVA film, and the water contact angle increased from 43.7° to 84.2°. DL/PVA composite film with 10 wt% addition shielded 95.8% of the UV spectrum (400–200 nm). Moreover, after incorporating the DL nanoparticles into the PVA matrix, the as-obtained DL/PVA composite films displayed good antioxidant activity by eliminating most of the DPPH free radicals. With 10 wt% addition of DL nanoparticles, the DPPH radical scavenging activity of DL/PVA composite film increased by about 76% compared with pure PVA film. These enhanced properties were attributed to the more phenolic hydroxyl groups of DL nanoparticles than of BL and the hydrogen-bonding interactions. In conclusion, the DES-phenolation pretreatment of lignin clearly improved the properties of PVA composite films. Furthermore, as both lignin and PVA are biodegradable, the lignin nanoparticle/PVA composite film may be a promising candidate for fully biodegradable robust coating materials with vital potential applications, such as UV-shielding and food packaging, etc. Full article

Poor breathability, inadequate flexibility, bulky wearability, and insufficient gas-adsorption capacity always limit the developments and applications of conventional chemical protective clothing (CPC). To create a lightweight, breathable, and flexible fabric with a high gas-absorption capacity, activated carbon (AC)-loaded poly(m-phenylene isophthalamide) (PMIA) porous composite fibres were fabricated from a mixed wet-spinning process integrated with a solvent-free phase separation process. By manipulating the pore parameters of as-spun composite fibres, the exposure-immobilization of AC particles on the fibre surface can offer a higher gas-absorption capacity and better AC-loading stability. To improve the mechanical properties of AC-loaded porous as-spun fibres and further optimize the pore-locking structures, the impact of the hot-drawing process on the evolution of pore parameters and the corresponding properties (including the gas absorption capacity, the mechanical performance, and the stability of AC particles during loading) was clarified. After the hot-drawing process, the inhomogeneous pore morphologies composed of mesopores/micropores from as-spun fibres changed into homogeneous and decreased mesopores. With the decrease in structural defects in homogeneous morphologies, the tensile strength of AC-loaded PMIA porous-drawn fibres increased to 1.5 cN/dtex. Meanwhile, the greater total pore volume and specific surface area after hot drawing also maintained the gas-absorption capacity of drawn composite fibres at 98.53 mg/g. Furthermore, the AC-loaded PMIA porous composite fibres also showed comparable performance to the commercial FFF02 absorption layer in terms of static absorption behaviour for different gas molecules and absorption–desorption multi-cycling evaluations. In addition, due to the size reduction in mesopores after the hot-drawing process, the loading stability of AC particles in the stretched composite fibres was more substantial. Full article

Parkinson’s disease (PD) is the second most common neurodegenerative disorder globally that lacks any disease-modifying drug for prevention or treatment. Oxidative stress has been identified as one of the key pathogenic drivers of Parkinson’s disease (PD). Edaravone, an approved free-radical scavenger, has proven to have potential against PD by targeting multiple key pathologies, including oxidative stress, focal mitochondria, and neuroinflammation. However, its bioavailability is potentially restricted due to its poor solubility and short half-life. This study aims to develop a simple and effective drug delivery system for edaravone to enhance its solubility, stability, and bioavailability to improve its neuroprotective efficacy. An MPEG-2000-DSPE-edaravone (MDE) micelle was prepared via solvent evaporation using MPEG-2000-DSPE as a carrier to encapsulate edaravone. The morphology, particle size, zeta potential, chemical structure, and edaravone loading of MDE were evaluated. We then investigated whether such targeted edaravone delivery could provide enhanced neuroprotection. A cell model of PD was established in PC12 cells through exposure to rotenone. The effects of MDE on PC12 cells treated with or without rotenone were evaluated using a cell counting kit-8, calcein acetoxymethyl ester (AM)–propidine iodide (PI) staining, and flow cytometry. Cell migration was evaluated using a wound healing assay. Additionally, the intracellular antioxidant study was performed using an ROS-level-detecting DCFH-DA probe, and the mitochondrial membrane potentials were evaluated using a JC-1 assay. MDE with a drug-loading content of 17.6% and an encapsulation efficiency of 92.8% was successfully prepared. The resultant MDE had a mean particle size of 112.97 ± 5.54 nm with a zeta potential of −42 mV. Cytotoxicity assays confirmed that the MDE (≤200 ug/mL) exhibited promising cytocompatibility with no significant effect on cell viability, cell cycle regulation, or apoptosis levels. Likewise, compared with the free edaravone, no effect on cell migration was noted for MDE. MDE might be able to target edaravone delivery into PC12 cells, increasing the mitochondrial membrane potential and providing a significant local antioxidant effect. The results demonstrated that MPEG-2000-DSPE could be a promising material for enhancing edaravone’s aqueous solubility, stability, and antioxidant effects. MDE could be a potential drug formulation for treating PD and other diseases in which oxidative stress plays a key role in pathogenesis. Full article