Search Results (6,437)

The solubilization of poorly water-soluble natural bioactive compounds remains a significant challenge. This study aims to design a ternary inclusion system to enhance the solubility of the poorly water-soluble compound Neohesperidin (NH). Soluble ternary cyclodextrin complexations (t-CDs) containing NH, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), and meglumine (MEG) were prepared and optimized. The optimized t-CDs were further characterized using Scanning Electron Microscopy (SEM), Powder X-ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and molecular docking (MD) techniques. The results suggested that NH formed was associated with MEG through hydrogen bonds with MEG, and was subsequently incorporated into the hydrophobic cavity of HP-β-CD, which may be a key factor in improving its solubility. The solubility of NH in water at 37 °C increased significantly from 0.16 mg/mL to 5.81 mg/mL in the optimized t-CDs (NH/MEG/HP-β-CD). Full article

Novel blend membranes containing S-PVA and PEBAX 1657 with a blend ratio of 8:2 (referred to as SPP) were prepared using a solution-casting technique. In the manufacturing process, sulfonated montmorillonite (S-MMT) in ratios of 0%, 3%, 5%, and 7% was used as a filler. The crystallinity of composite membranes has been investigated by X-ray diffraction (XRD), while the interaction between the components was evaluated using Fourier-transform infrared spectroscopy (FT-IR). With increasing filler content, good compatibility between the components due to hydrogen bonds was established, which ultimately resulted in improved tensile strength and chemical stability. In addition, due to the sulfonated moieties of S-MMT, the highest ion exchange capacity (0.46 meq/g) and water uptake (51.61%) can be achieved at the highest filler content with an acceptable swelling degree of 22.65%. The composite membrane with 7% S-MMT appears to be suitable for application in proton exchange membrane fuel cells (PEMFCs). Amongst the membranes studied, this membrane achieved the highest current density and power density in fuel cell tests, which were 149.5 mA/cm² and 49.51 mW/cm². Our fluorine-free composite membranes can become a promising new membrane family in PEMFC applications, offering an alternative to Nafion membranes. Full article

Extrusion processing of plasticized cassava starch, a prominent industrial crop, with chemical additives offers a thermo-mechanical approach to modify starch structures through physical and chemical interactions. This research investigates the interaction and morphology of thermoplastic cassava starch (TPS) blended with tetrasodium pyrophosphate (Na₄P₂O₇), sodium tripolyphosphate (Na₅P₃O₁₀), sodium hexametaphosphate (Na₆(PO₃)₆), sodium erythorbate (C₆H₇O₆Na), and sodium nitrite (NaNO₂) via twin-screw extrusion. The effects of these additives on the chemical structure, thermal profile, water absorption, and solubility of the TPS were examined. The high temperature and shearing forces within the extruder disrupted hydrogen bonding at α-(1-4) and α-(1-6) glycosidic linkages within anhydroglucose units. Na₄P₂O₇, Na₅P₃O₁₀ and Na₆(PO₃)₆ induced starch phosphorylation, while ¹H NMR and ATR-FTIR analyses revealed that C₆H₇O₆Na and NaNO₂ caused starch hydrolysis. These additives hindered starch recrystallization, resulting in higher amorphous fractions that subsequently influenced the thermal properties and stability of the extruded TPS. Furthermore, the type and content of the added modifier influenced the water absorption and solubility of the TPS due to varying levels of interaction. These modified starch materials exhibited enhanced antimicrobial properties against Escherichia coli and Staphylococcus aureus in polyester blends fabricated via extrusion, with nitrite demonstrating the most potent antimicrobial efficacy. These findings suggest that starch modification via either phosphorylation or acid hydrolysis impacts the thermal properties, morphology, and hydrophilicity of extruded cassava TPS. Full article

Hydrogen barrier coatings with Al₂O₃ as the main component are a good choice for solving the hydrogen embrittlement problem during hydrogen transportation in long-distance pipelines. However, the difference in the coefficients of thermal expansion between the substrate and the Al₂O₃ coating limits its further utilisation and development. In this study, rare earth oxides were added to the molten aluminium solution, and a Fe-Al transition layer was introduced on the surface of X80 steel by hot-dip plating to solve the thermal mismatch. Here, the microstructure and bonding strength of the hot-dip aluminium layer were investigated. It is found that the hot-dip aluminium coating consists of the outermost aluminium-rich layer and the inner Fe-Al alloy layer, and the microstructure of the two will change with the change in dip plating parameters. The best overall performance of the hot-dip aluminium layer was obtained from X80 steel substrate at a dip plating temperature of 700 °C and a dip plating time of 5 min. This coating has a good interface, moderate thickness, and a bond strength of 49 N. This study provides a reference value for solving the thermal mismatch between the steel substrate and the Al₂O₃ hydrogen barrier coating generated by subsequent anodising. Full article

Betacyclodextrin (β-CD)-assisted extracts of green rooibos displayed elevated polyphenolic content and antioxidant activity compared with aqueous extracts. This study aimed to analyse the physicochemical properties of aqueous green rooibos and 15 Mm β-CD at 40 °C for 60 min. Sorption isotherms and colour (L*a*b*C*) were evaluated. Thermogravimetric analysis and Fourier transform infrared were conducted to verify encapsulation. Sorption isotherm studies revealed that β-CD reduced water uptake, resulting in a reduction in the monolayer value of GRE (7.90) to 6.40 for β-GRE. Betacyclodextrin contributed to increased lightness (L*) and decreased redness (a*) of green rooibos. However, storing extracts at varied water activity resulted in a reduction in L* and chroma (C*), with a higher reduction observed for GRE than β-GRE. Thermogravimetric analysis revealed that GRE degraded at 180 °C, followed by β-GRE at 260 °C and β-CD at 340–375 °C. Betacyclodextrin increased the thermal stability of green rooibos; as a result, β-GRE displayed a superposition of GRE and β-CD in its thermogram, confirming the formation of inclusion complexes. Fourier transform infrared spectra indicated the disappearance or shifting of characteristic peaks, with the formation of hydrogen bonds between GRE and β-CD at the 1255 cm⁻¹ band depicting C–O stretching of carboxylic acid. Full article

Self-healing, stretchable, and moldable hydrogels have a great potential application in tissue engineering and soft robotics. Despite great success in reported hydrogels, it is still a great challenge to construct the moldable hydrogels with an ultrafast self-healing performance. Herein, the composite hydrogels (PBLH) with ultrafast self-healing, stretchable, and moldable properties were successfully constructed by poly (vinyl alcohol) (PVA), borate (B), ε-poly-L-lysine (EPL), and hyaluronic acid (HA) based on an efficient one-pot method. Fourier transform infrared spectroscopy, X-ray diffraction, and rheological measurements confirmed the formation of a dynamic network among PVA, B, EPL, and HA through the cross-linking of dynamic borate bonds, electrostatic interaction, and hydrogen bonding. Having fabricated the dynamic network structure, the damage gap of the composite hydrogels can heal within 1 min, presenting an excellent self-healing ability. Simultaneously, the composite hydrogels can be molded into various shapes, and the length of the composite hydrogels can be stretched to 15 times their original length. In addition, the composite hydrogels exhibited an excellent antibacterial property against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Our results illustrated that the composite hydrogels not only retain the advantages of traditional hydrogels but also possess ultrafast self-healing, outstanding stretchable and antibacterial properties, presenting a prospective candidate for constructing biomedical materials. Full article

In this study, amino-functionalized magnetic particles (iron oxide@SiO₂-NH₂) with core-shell structures were synthesized and evaluated for rapid boron removal from aqueous solutions. The results showed that the specific surface area of the iron oxide@SiO₂-NH₂ (131.24 m²⋅g⁻¹) increased greatly compared to pure iron oxide (30.98 m²⋅g⁻¹). The adsorption equilibrium was less than 2 h, with an adsorption capacity of 29.76 mg⋅g⁻¹ at pH = 6 at 15 °C. The quasi-second-order kinetic model described the boron adsorption process well, and both the Langmuir and Freundlich models were suitable for characterizing the adsorption isotherms. The zeta potential and XPS analysis before and after adsorption revealed that the main adsorption mechanism was the hydrogen bonding formation between the terminal -NH₂ groups of the adsorbent and the boric acid. In addition, the adsorbent still maintained a high adsorption performance after five adsorption–desorption cycles, which illustrated that the iron oxide@SiO₂-NH₂ may be a potential adsorbent for environmental boron removal treatment. Full article

The geometric and electronic structures and the bonding of U₅M⁺ and T₅M⁺ (U = uracil, T = thymine, M = Ag, Au) cluster cations have been investigated with density functional theory methods. They have a perfectly planar structure with C_5h symmetry and significant stability, containing self-complementary N-H···O hydrogen bonds and five Au-O or Ag-O contacts. The energy gap between the LUMO and HOMO in the U₅Ag⁺ cluster is 4.2 eV, which is twice as large as the HOMO-LUMO gap observed in the U₅Au⁺ cluster. This notable difference clearly indicates that the U₅Ag+ cluster possesses substantially greater stability compared to the U₅Au⁺ cluster. This finding is consistent with the results from the energy decomposition analyses, which show that the total interaction energy of U₅Ag⁺ is significantly higher than that of U₅Au⁺. The same trend is observed in T₅M⁺ as well. The interaction between the metal atoms, whether gold (Au) or silver (Ag), and the nucleobase is not predominantly controlled by electrostatic forces, as initially believed. Instead, it is primarily characterized by pronounced covalent bonding effects. Full article

Drawing inspiration from the structural resemblance between a natural product N-(3-carboxypropyl)-2-acetylpyrrole and phenylbutyric acid, a pioneer HDAC inhibitor evaluated in clinical trials, we embarked on the design and synthesis of a novel array of HDAC inhibitors containing an N-linked 2-acetylpyrrole cap by utilizing the pharmacophore fusion strategy. Among them, compound 20 exhibited potential inhibitory activity on HDAC1, and demonstrated notable potency against RPMI-8226 cells with an IC₅₀ value of 2.89 ± 0.43 μM, which was better than chidamide (IC₅₀ = 10.23 ± 1.02 μM). Western blot analysis and Annexin V-FTIC/propidium iodide (PI) staining showed that 20 could enhance the acetylation of histone H3, as well as remarkably induce apoptosis of RPMI-8226 cancer cells. The docking study highlighted the presence of a hydrogen bond between the carbonyl oxygen of the 2-acetylpyrrole cap group and Phe198 of the HDAC1 enzyme in 20, emphasizing the crucial role of introducing this natural product-inspired cap group. Molecular dynamics simulations showed that the docked complex had good conformational stability. The ADME parameters calculation showed that 20 possesses remarkable theoretical drug-likeness properties. Taken together, these results suggested that 20 is worthy of further exploration as a potential HDAC-targeted anticancer drug candidate. Full article

A zeolitic sample, named MT-ZLSH, was synthesized using mining tailings (MT) as the precursor material, resulting in a structure comprising: Linde type A (LTA) and sodalite-hydroxysodalite (ZLSH). This naming convention reflects the material’s origin and its structural characteristics. The material was further modified by incorporating lithium, producing MT-ZLSH-Li⁺. Physicochemical characterizations were performed, and the material was evaluated for its potential to remove methylene blue (MB) from synthetic wastewater through adsorption and photocatalysis. Efficient adsorption was observed under typical wastewater pH conditions, with a maximum adsorption capacity of 23.4 mg·g⁻¹, which fit well with the Langmuir isotherm model. The key mechanisms governing MB adsorption were identified as ion exchange, electrostatic attraction, and hydrogen bonding. The adsorption process was exothermic, with kinetic data fitting both the pseudo-second order and intraparticle diffusion models, achieving 82% removal and a maximum adsorption capacity of 40 mg·g⁻¹ over 12 h. MB adsorption followed a two-step process, initially involving film diffusion, followed by intraparticle diffusion. Additionally, photocatalytic degradation of MB achieved 77% degradation within 180 min. However, a decrease in reusability was observed during a second cycle of MB adsorption and photodegradation, highlighting the need for further optimization to enhance the material’s long-term performance. Full article

Hydrogen boride (HB) sheets are emerging as a promising two-dimensional (2D) boron material, with potential applications as unique electrodes, substrates, and hydrogen storage materials. The 2D layered structure of HB was successfully synthesized using an ion-exchange method. The chemical bonding and structure of the HB sheets were investigated using Fourier Transform Infrared (FT–IR) spectroscopy and Transmission Electron Microscopy (TEM), respectively. X-ray photoelectron spectroscopy (XPS) was employed to study the chemical states and transformation of the components before and after atomic hydrogen adsorption, thereby elucidating the atomic hydrogen adsorption process on HB sheets. Our results indicate that, upon atomic hydrogen adsorption onto the HB sheets, the B-H-B bonds were broken and converted into B-H bonds. This research highlights and demonstrates the changes in chemical states and component transformations of the boron element on the HB sheets’ surface before and after atomic hydrogen adsorption, thus providing a clearer understanding of the unique bonding and structural characteristics of the HB sheets. Full article

N-heterocycles with quinoline structures hold significant importance within the chemical and pharmaceutical industries. However, achieving their efficient transformations remains a vital yet challenging endeavor. Herein, a series of W-doped Ga₂O₃-NC catalysts were synthesized using a Ga-MOF-derived strategy through a simple solvothermal method, with a remarkably high activity and selectivity towards the oxidative dehydrogenation of N-heterocycles. Furthermore, the MOF-derived W-doped Ga₂O₃-NC catalysts exhibit remarkable substrate tolerance and recyclability. The outstanding catalytic activity was attributed to the robust synergistic interaction between the W species and the Ga₂O₃-NC carrier, which facilitates the activation of hydrogen atoms in the C-H and C=N bonds on both the oxygen molecule and the substrate to produce H₂O₂. Additionally, the solvent effect of methanol can significantly enhance dehydrogenation due to its strong ability to donate and accept protons of hydrogen bonding. The present work provides a new approach to MOF-derived non-precious metal catalysts for achieving the efficient oxidation dehydrogenation of N-heterocycles. Full article

Carbon materials supported Fe-based catalysts possess great potential for the thermal-catalytic hydrogenation of CO₂ into valuable chemicals, such as alkenes and oxygenates, due to the excellent active sites’ accessibility, appropriate interaction between the active site and carbon support, as well as the excellent capacities in C-O bond activation and C-C bond coupling. Even though tremendous progress has been made to boost the CO₂ hydrogenation performance of carbon-supported Fe-based catalysts, e.g., additives modification, the choice of different carbon materials (graphene or carbon nanotubes), electronic property tailoring, etc., the effect of carbon support porosity on the evolution of Fe-based active sites and the corresponding catalytic performance has been rarely investigated. Herein, a series of porous carbon samples with different porosities are obtained by the K₂CO₃ activation of petroleum pitch under different temperatures. Fe-based active sites and the alkali promoter Na are anchored on the porous carbon to study the effect of carbon support porosity on the physicochemical properties of Fe-based active sites and CO₂ hydrogenation performance. Multiple characterizations clarify that the bigger meso/macro-pores in the carbon support are beneficial for the formation of the Fe₅C₂ crystal phase for C-C bond coupling, therefore boosting the synthesis of C₂₊ chemicals, especially C₂₊ alcohols (C₂₊OH), while the limited micro-pores are unfavorable for C₂₊ chemicals synthesis owing to the sluggish crystal phase evolution and reactants’ inaccessibility. We wish our work could enrich the horizon for the rational design of highly efficient carbon-supported Fe-based catalysts. Full article

The clean and efficient utilization of coal is a promising way to achieve carbon neutrality. Coking coal is a scarce resource and an important raw material in the steel industry. However, the presence of pyrite sulfur affects its clean utilization. Nonetheless, this pyrite could be removed using depressants during flotation. Commonly used organic depressants (sodium lignosulfonate (SL), calcium lignosulfonate (CL), and pyrogallol (PY)) and inorganic depressants (calcium oxide (CaO) and calcium hypochlorite (Ca(ClO)₂)) were chosen in this study. Their inhibition mechanism was discussed using FTIR, XPS, and molecular dynamics (MD) methods. The desulfurization ability of organic depressants was shown to be better than inorganic ones. Among the organic depressants, PY proved to be advantageous in terms of low dosage. Physical adsorption was identified as the main interaction form of SL, CL, and PY onto the surface of pyrite, as evidenced from FTIR and XPS analyses. Similarly, MD simulation results showed that hydrogen bonds played a proactive role in the interactions between PY and pyrite. The diffusion coefficient of water molecules on the pyrite surface was also observed to decrease when organic depressants were present, indicating an increase in the hydrophilicity of pyrite. This research is of great significance to utilize sulfur-containing coal and minerals. Full article

This study characterized the binding mechanisms of the lectin cMoL (from Moringa oleifera seeds) to carbohydrates using spectroscopy and molecular dynamics (MD). The interaction with carbohydrates was studied by evaluating lectin fluorescence emission after titration with glucose or galactose (2.0–11 mM). The Stern–Volmer constant (Ksv), binding constant (Ka), Gibbs free energy (∆G), and Hill coefficient were calculated. After the urea-induced denaturation of cMoL, evaluations were performed using fluorescence spectroscopy, circular dichroism (CD), and hemagglutinating activity (HA) evaluations. The MD simulations were performed using the Amber 20 package. The decrease in Ksv revealed that cMoL interacts with carbohydrates via a static mechanism. The cMoL bound carbohydrates spontaneously (ΔG < 0) and presented a Ka on the order of 10², with high selectivity for glucose. Protein–ligand complexes were stabilized by hydrogen bonds and hydrophobic interactions. The Hill parameter (h~2) indicated that the binding occurs through the cMoL dimer. The loss of HA at urea concentrations at which the fluorescence and CD spectra indicated protein monomerization confirmed these results. The MD simulations revealed that glucose bound to the large cavity formed between the monomers. In conclusion, the biotechnological application of cMoL lectin requires specific methods or media to improve its dimeric protein structure. Full article