Search Results (621)

Protein molecularly imprinted polymers (MIPs), as artificial antibodies, are promising for protein separation due to their low cost, easy preparation, and high stability, but their performance is limited by poor mass transfer, imprecise imprinting, and single interaction modes. Herein, dendritic mesoporous silica nanoparticles (DMSNs) were used as the support, and a self-designed multifunctional poly(ionic liquid) macromonomer (p(VIMCD-co-VAIM-co-VSIM-co-VVIM)) served as the functional monomer to achieve directional anchoring of cytochrome C (Cyt-C). Surface-imprinted microspheres (DMSNs@MPS@PILs-MIPs) were prepared via free-radical copolymerization for Cyt-C recognition. The DMSNs possessed interconnected mesoporous channels, good dispersibility, an average particle size of ~80 nm, and a specific surface area of 267.97 m²/g. Ionic liquid monomers were synthesized via alkylation, and the macromonomer was constructed through a two-step method. Molecular dynamics simulations and spectroscopic characterization revealed the macromonomer-stabilized Cyt-C conformation, with interactions dominated by van der Waals forces. The DMSNs@MPS@PILs-MIPs featured a thin imprinted layer (~5 nm) to reduce mass-transfer resistance. Adsorption studies showed Cyt-C adsorption followed Langmuir and pseudo-second-order models, with a maximum capacity of 383.14 mg/g and an imprinting factor of 2.17. Only 12% capacity loss occurred after repeated cycles, indicating robust regeneration stability. This study provides a feasible strategy for constructing protein surface-imprinted polymers based on multifunctional synergistic interactions and conformational stabilization. Full article

Presently, there is little to no literature that investigates the effect of electron beams on para-aramid (Kevlar^®) fiber polymer (KFRP) composites. Therefore, we assessed the effect of homogeneous low-potential electron beam irradiation (HLEBI) on Kevlar-reinforced recyclable thermoplastic (TP) polypropylene (PP) (KFRPP). Samples were assembled in an interlayered configuration of four-sized KF plies between five PP sheets [PP1-KF1-PP2-KF2-PP3-KF2-PP2-KF1-PP1] designated [PP]₅[KF]₄, which were hot-pressed at 493 K at 4 MPa for 7 min. Experimental results show when an HLEBI setting of 250 kV cathode potential (V_c) at an 86 kGy dose is applied to finished sample surfaces, the Charpy impact strength (a_uc) at median fracture probability (P_f of 0.50) is increased 59% from 72.5 kJ/m² when untreated to 115.6 kJ/m² thereafter, while a 170 kV–129 kGy setting increased a_uc about 15%, to 83.3 kJ/m², when compared to the untreated sample. Scanning electron microscopy (SEM) showed the 250 kV–86 kGy HLEBI increases KF/PP adhesion with increased consolidation and KF bundling, while the electron spin resonance (ESR) showed HLEBI generates dangling bonds (DBs) in KF and PP, which is evidence of the strengthening KF/PP interface. X-ray photoelectron spectroscopy (XPS) of the N1s spectrum of Kevlar fiber from the fracture region of the untreated sample showed a dominant peak at 399.5 eV with 82.7% area, which is characteristic of the Kevlar backbone N–(C=O)–, indicating poor adhesion with fiber pullout. However, the dominant peak was shifted in the 250 kV–86 kGy sample to that of strongly bonded imines, –C=N–, at 398.6 eV and 36.8%, indicating strong bonds generated at the KF/PP interface. Together, the N1s, C1s and O1s spectra indicate increased polar groups, reduced weak Van der Waals forces, and the generation of a strong active nitrogen-containing interphase, acting to reduce fiber pullout to increase the impact strength of the [PP]₅[KF]₄ composite system. Full article

Aiming to address the problems of shield chamber blockage and poor muck discharge faced by earth pressure balance shields during tunneling in sandy strata, bentonite slurry is used for muck improvement. Using a multi-scale approach combining macro-scale experiments, micro-scale analysis, and molecular dynamics simulations, this study systematically investigates the interface interactions between particles of sandy soil in shield tunneling and the improvement mechanism of sodium-based bentonite slurry additives. Through the macroscopic experiment, the sodium bentonite slurry soil–water ratio of 1:7 and injection ratio of 25% showed the best improvement effect. After improvement, the permeability coefficient decreased by 99.72%; the cohesion of the excavated soil increased from 3.055 kPa to 11.458 kPa, representing a 275.06% increase; and the angle of internal friction decreased from 42.318° to 36.985°, a decrease of 12.60%. The improvement was significant. Through SEM, XRD, and FTIR microanalysis, it is found that bentonite slurry forms a flexible film on the surface of sandy soil. By coating sand particles, filling voids in the soil, and enhancing interparticle cohesion, it improves the properties of the soil. On the nanoscale, a Na-MMT/SiO₂ system model is established based on molecular dynamics simulations to elucidate the interactions between bentonite slurry and sand particle interfaces. The results indicate the presence of van der Waals forces and hydrogen bonds between Na-MMT and SiO₂. Interlayer water molecules form a hydrogen bond network that strengthens interfacial bonding, enabling bentonite slurry to tightly adhere to soil particle surfaces. This improves the microstructure of the soil, thereby enhancing its macroscopic properties. Full article

This study presents the synthesis and use of a novel bamboo-derived magnetic activated carbon (BMAC) for the effective removal of cationic and anionic dyes, specifically methylene blue (MB), methyl orange (MO), and sunset yellow (SY), from aqueous solutions. The adsorbent was synthesized using thermal carbonization and subsequent inclusion of magnetic oxide, yielding a porous structure with improved adsorption and magnetic separation properties. Thorough characterization utilizing SEM, EDX, BET, FTIR, XRD, and TGA/DTA validated the creation of a highly porous material including uniformly dispersed magnetic particles and several surface functional groups. Batch adsorption tests were performed to examine the influences of contact time, adsorbent dosage, initial dye concentration, pH, and temperature. The findings indicated rapid adsorption kinetics, with equilibrium reached in around 60–70 min, and adsorption capacity ranked as MB > MO > SY. Augmenting adsorbent dosage enhanced removal efficiency but diminished adsorption capacity per unit mass due to site unsaturation. The maximum adsorption capacities (q_m) of BMAC were 58.9, 56.3, and 32.7 mg/g for MB, MO, and SY, respectively, as determined from the Langmuir isotherm model, indicating superior performance compared with other reported magnetic activated carbon. The adsorption process was determined to be exothermic and spontaneous, as evidenced by thermodynamic characteristics. The equilibrium data were optimally characterized by the Langmuir isotherm model, indicating monolayer adsorption, whereas the kinetic studies conformed to the pseudo-second-order model, signifying that chemisorption is predominant. The adsorption mechanism encompasses electrostatic interactions, π–π stacking, hydrogen bonding, van der Waals forces, pore filling, and surface complexation with magnetic oxides. The findings indicate that BMAC is an efficient, sustainable, and magnetically recoverable adsorbent for the elimination of both cationic and anionic dyes from wastewater. Full article

In this study, a polyvinyl alcohol/carboxymethyl chitosan (PVA/CCTS) hydrogel was synthesized via free radical polymerization and employed for the adsorption of Rhodamine B (RhB) from aqueous solution. The hydrogel was systematically characterized by FTIR, SEM, XPS, and BET analyses, confirming its interconnected porous network and functional group composition. Under optimized conditions (adsorbent dosage = 0.1 g, pH = 6, RhB concentration = 65 mg·L⁻¹, and T = 298.15 ± 2 K), the maximum adsorption capacity reached 15.88 mg·g⁻¹. Kinetic analysis showed that the pseudo-second-order model best described the adsorption behavior under optimal conditions, indicating that the uptake of RhB is governed by multiple interaction mechanisms rather than simple physisorption alone. The equilibrium data were best fitted by the Freundlich isotherm (R² = 0.976), indicating surface heterogeneity of the hydrogel. Thermodynamic evaluation revealed an endothermic (ΔH = 28.38 ± 4.40 kJ·mol⁻¹), with adsorption efficiency improving at elevated temperatures. The hydrogel retained appreciable adsorption capacity after three adsorption–desorption cycles (5.78 mg·g⁻¹ at the third cycle). Density functional theory (DFT) calculations identified -COOH and -NH₂ groups as the primary active sites, and molecular electrostatic potential analysis confirmed that electrostatic interactions between the negatively charged hydrogel surface and cationic RhB drive the initial adsorption. Molecular dynamics (MD) simulations over 100 ns further demonstrated that van der Waals forces constitute the dominant driving force, supplemented by electrostatic interactions and hydrogen bonding, with the hydrogel’s cross-linked network stabilizing adsorbed RhB molecules. The integrated experimental computational approach provides a comprehensive mechanistic understanding of RhB adsorption on PVA/CCTS hydrogel, offering guidance for the rational design of polysaccharide-based adsorbents for dye-contaminated wastewater treatment. Full article

4-Methyl- (1) and 4-ethyl-8-hydroxyquinoline (2) crystallize from a mixture of diethyl ether and chloroform in the triclinic space group P$\overline{1}$. X-ray analysis reveals that both compounds form discrete molecular dimers stabilized by intermolecular O-H∙∙∙N and C-H∙∙∙O hydrogen bonds, resulting in $R_2^2\left(5\right)$ cyclic synthons. This pattern of hydrogen bonds is further stabilized by intramolecular O-H∙∙∙N bonds so that the quinoline nitrogen atom acts as a bifurcated binding site. The dimers exhibit a planar geometry and arrange into layer-like structures held together by π∙∙∙π stacking and van der Waals forces. While the fundamental bonding motifs are similar, the increased steric demand of the ethyl group in compound 2 induces a shift in the crystallographic orientation of the layers and alters the degree of π-overlap compared to the methyl-substituted analogue 1. Full article

To promote green chemistry and improve the utilization of plant resources, flavonoids from Dalbergia pinnata (Lour.) Prain were extracted in this study by combining NADES (natural deep eutectic solvents) with UAE (ultrasound-assisted extraction). Among the 13 synthesized NADES, choline chloride (ChCl)–urea (NADES-13) exhibited the highest extraction rate, outperforming traditional organic solvents. The optimal conditions determined by response surface methodology (RSM) were as follows: ChCl–urea molar ratio of 1:3, moisture content of 60%, liquid-to-material ratio of 28.5 mL/g, ultrasonic extraction time of 49 min, and temperature of 62 °C. Under these conditions, the extraction rate reached 117.95 ± 5.97 mg/g, a 73.5% improvement compared with 80% EtOH extraction. The comparison of the two algorithms showed that RSM (R = 0.9981, RMSE = 0.6570) had better fitting accuracy and prediction stability under small sample conditions than MLP (R = 0.9427, RMSE = 5.261) and RF (R = 0.9431, RMSE = 5.2442). DFT (density functional theory) analysis demonstrated that hydrogen bonds, Van der Waals forces, and cation–π interactions mediate the interaction between NADES-13 and flavonoids. Ultrasonic cavitation-induced cell wall damage and the hydrogen-bond network of NADES-13 were confirmed separately by SEM (scanning electron microscopy) and FTIR (Fourier transform infrared spectroscopy). In vitro experiments showed that the extract possessed concentration-dependent antioxidant activity and strong antibacterial activity, with an inhibition rate of 96.87 ± 5.09% against Escherichia coli at a concentration of 0.04 mg/mL. In this study, a “Smart Optimization–Molecular Mechanism–Activity Verification” green extraction system was developed, which offers an efficient and environmentally friendly strategy for extracting plant bioactive components and contributes to the progress of green chemistry. Full article

Recognized for its dual nutritional and therapeutic value, the fungus Hericium erinaceus is increasingly acknowledged as a rich resource of naturally derived α-glucosidase inhibitors. In this study, eight compounds were isolated from H. erinaceus, including three novel compounds designated as erinacerins X−Z (1, 2, and 6). Their absolute configurations were definitively elucidated using a combination of NMR, HR-MS, and ECD calculations. Furthermore, an integrated screening strategy combining molecular docking, molecular dynamics (MD) simulations, and surface plasmon resonance (SPR) analysis identified two isoindolin-1-ones (2 and 3) as potent naturally derived α-glucosidase inhibitors. Notably, in vitro testing established compounds 2 and 3 as robust α-glucosidase inhibitors, affording IC₅₀ values of 17.80 ± 1.03 μM and 19.50 ± 1.33 μM, respectively. MD simulations revealed that electrostatic interactions and van der Waals forces are the primary drivers of this intermolecular association. These findings were further corroborated by SPR analysis, which quantified their high-affinity binding kinetics to the enzyme. Overall, this combined approach establishes a solid foundation for the discovery and development of natural α-glucosidase inhibitors from H. erinaceus. Full article

Alzheimer’s disease (AD) is a common neurodegenerative disorder linked to cholinergic dysfunction, with butyrylcholinesterase (BChE) being a key therapeutic target for moderate–severe AD. Cortex Mori Radicis, a traditional Chinese medicinal herb, is rich in Diels–Alder adducts with potential neuroprotective effects; here, eighteen Diels–Alder adducts (four new: morusalbanol B–E, 1–4) were isolated and identified from its 80% ethanol extract. Their cholinesterase inhibitory activities were assessed via Ellman’s method, with enzyme kinetics and molecular docking performed for active compounds. Most compounds showed selective BChE inhibition, with kuwanon X (14) being the most potent (IC₅₀ = 2.3 μM). morusalbanol B (1), cathayanon A (8), and kuwanon G (12) acted as noncompetitive inhibitors, while Morusalbanol C (2) and kuwanon X (14) were mixed competitive inhibitors. Molecular docking suggested that potent inhibitors occupied the BChE active pocket via hydrogen bonds, π-π stacking, and hydrophobic interactions with Trp82, His438, and Phe329. MD simulations and MM-GBSA binding free energy analysis further verified that all three representative complexes (1, 8, and 14) achieved favorable thermodynamic and structural stability, with binding driven primarily by van der Waals forces. Residue decomposition revealed that Trp82 and Phe329 served as core binding hotspots for all tested inhibitors. Structure–activity analysis indicated that a cis-trans methylcyclohexene configuration, shorter aliphatic ester chains, and more prenyl groups enhanced BChE inhibition. This study provides new lead compounds and a systematic molecular mechanism basis for developing novel anti-AD BChE inhibitors from natural products. Full article

Adsorption properties of graphene oxide (GO) and its organo-modified analog (GO-HDTMA), treated with the hexadecyltrimethylammonium (HDTMA) cationic surfactant, were evaluated for the removal of persistent pharmaceutical products (PPs): an anionic diclofenac (DCF) anti-inflammatory, a cationic metoprolol (MTP) beta-blocker, and a nonionic sulfamethoxazole (SMX) antibiotic. Adsorption isotherms, fitted by Langmuir and Freundlich models, together with FTIR data, demonstrate that both GO and GO-HDTMA are effective adsorbents for DCF. The adsorption is primarily governed by both π–π and van der Waals interactions, leading to saturation of the accessible C sp² carbon domains at a maximum uptake of 4.2 mmol g⁻¹. In contrast, due to its cationic nature, MTP is not removed using GO-HDTMA, while it is effectively adsorbed at about 0.5 mmol g⁻¹ for GO via electrostatic attractive forces. SMX is adsorbed by both materials, although its uptake remains limited on GO. The presence of hydrophobic domains in GO-HDTMA enhances SMX adsorption through weak intermolecular interactions. These results highlight the tunability of GO-based hybrid materials and their potential for the selective removal of a large spectrum of emerging pharmaceutical contaminants. Full article

This study focused on the inhibitory effects of wheat bran feruloyl oligosaccharides (FOs) on the formation of AGEs in three bovine serum albumin (BSA)-based non-enzymatic glycation models, namely BSA-fructose, BSA-methylglyoxal (MGO), and BSA-glyoxal (GO). In the BSA-fructose model, FOs at 0.25 mg/mL achieved a 62% inhibition rate of fructosamine, equivalent to approximately 78% of the activity of the positive control aminoguanidine (AG), and reduced fluorescent AGEs by over 50% on day 12. Additionally, FOs suppressed the accumulation of α-dicarbonyl compounds, key intermediates in the glycation pathway. In the BSA-MGO and BSA-GO system, the decreased fluorescence intensity of tryptophan residues indicated that FOs bound to BSA, inducing conformational changes in the protein microenvironment; this binding also inhibited protein carbonyl formation and the loss of thiol groups, thereby modulating the protein glycation process. Compared with their precursors (ferulic acid, FA; xylooligosaccharides, XOS), FOs exhibited comparable or even superior inhibitory activity against specific AGE subtypes, suggesting a synergistic effect between the feruloyl and oligosaccharide moieties. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that FOs reduced the band intensity of 90 kDa AGEs in the glycation system, indicating the inhibition of protein-fructose cross-linking. Fluorescence spectroscopy confirmed that FOs dynamically quenched BSA with a single binding site, and thermodynamic calculations demonstrated that the binding was spontaneous (ΔG < 0), primarily driven by hydrogen bonds and van der Waals forces (ΔH < 0, ΔS < 0). This study systematically investigated the anti-glycation activities of FOs and their precursors. The findings demonstrate that FOs are promising natural glycation inhibitors and provide important theoretical and experimental support for related research. Furthermore, this study establish a basis for the green and high-value utilization of agricultural by-products like wheat bran. Full article

Boundary lubrication plays a crucial role in determining the service performance and operational lifespan of mechanical components. However, continuum mechanics models and experimental studies are unable to elucidate the dynamic evolution of intermolecular interactions at the interface under boundary lubrication from a microscopic perspective, including phenomena such as asperity contact and lubricant film rupture. In this study, a molecular dynamics simulation approach was employed to construct a boundary lubrication friction model incorporating lubricant molecules, aiming to investigate the influence of applied load and asperity height on the dynamic evolution of atomic interactions at the interface from the perspective of energy variation, under conditions both with and without asperity contact. The results indicate that van der Waals interactions dominate the frictional response, and severe asperity contact leads to a sharp increase in van der Waals energy, which in turn results in a decrease in normal force, thereby increasing the friction coefficient. When the upper and lower surfaces remain separated by the lubricant, an increase in van der Waals energy leads to higher friction force, consequently elevating the friction coefficient. In the absence of contact, the friction coefficient decreases with increasing load; however, once asperity contact occurs, higher loads accelerate lubricant film failure and intensify direct interfacial contact, leading to more pronounced stick–slip oscillations and increased wear. This study provides atomic-scale insights for the design and performance optimization of boundary lubrication interfaces. Full article

The new method proposed in this study, featuring a one-finger gripper, uses three types of forces—van der Waals force, capillary force, and coupling force due to ice—to grip and release microobjects to submillimeter-sized objects (5 to 300 µm). The gravitational force of an object can be neglected in the case of microobjects, but this is not the case for submillimeter-sized objects. This is the first reason that we use the coupling force due to ice; the second reason is that the shape of a micro- or submillimeter-sized object does not matter in this case. The usage of all three forces yields greater versatility regarding objects of different sizes and shapes and, consequently, greater overall reliability in gripping or releasing compared with methods that use only one or two of the mentioned forces. In this study, the laboratory set-up involved the active control of the temperature for both the one-finger gripper and the releasing surface for objects from −25 °C to 40 °C in a closed dust-free chamber in atmospheric air at relative humidity (RH) = 30%. A relatively low RH was achieved with the RH controller, enabling the release or grip procedures to last approx. 2–3 s for microobjects and 6 s for submillimeter-sized objects with the same equipment. Full article

Hypertension is a severe global public health issue. Food-derived angiotensin-converting enzyme (ACE)-inhibitory peptides have shown great potential as safe and effective alternatives to synthetic antihypertensive drugs. Camel milk is rich in bioactive peptides. This study aimed to screen for ACE-inhibitory peptides from hydrolyzed camel casein, explore their inhibitory mechanisms and endothelial protective effects in vitro, and reveal their potential antihypertensive pathways using network pharmacology. This study screened three peptides with angiotensin-converting enzyme (ACE) inhibitory activity from enzymatically hydrolyzed camel casein components: MVPFLQPK, VPFLQPKVM, and QKWKFL, with IC₅₀ values of 277.1, 396.9, and 486.9 μmol/L, respectively. Enzyme inhibition kinetics analysis indicated that MVPFLQPK exhibited a non-competitive inhibition pattern, VPFLQPKVM exhibited a mixed inhibition pattern, and QKWKFL exhibited a competitive inhibition pattern. Molecular docking revealed that all three peptides formed hydrogen bond interactions with ACE, and QKWKFL and VPFLQPKVM directly bound to the enzyme’s active site to inhibit substrate catalysis. Molecular dynamics simulation further confirmed the high stability of the three peptide–ACE complexes, with binding free energies from −34.24 to −51.19 kcal/mol. The primary contributing forces include hydrogen bonds, van der Waals interactions, electrostatic forces, and nonpolar solvation effects. Network pharmacology analysis suggested that these peptides may exert synergistic antihypertensive effects by regulating multiple blood pressure-related pathways, including the renin–angiotensin system, renin secretion, and calcium signaling pathways, by acting on key targets such as ACE, REN, SRC, and MMP9. Cell experiments demonstrated that all three peptides exhibited no cytotoxicity in the Ang II-induced HUVEC injury model, significantly promoted NO release, inhibited ET-1 secretion, and possessed endothelial protective potential. This study investigated the in vitro ACE-inhibitory mechanism of peptides derived from camel milk and their potential role in blood pressure regulation, providing experimental evidence for subsequent in vivo activity validation and the development of functional camel milk protein products. Full article

Pancreatic lipase (PL) plays a central role in dietary lipid digestion and is a promising target for food-derived inhibitors. In this study, pea protein hydrolysates (PPHs) with PL inhibitory activity were prepared by enzymatic hydrolysis and characterized for their functional and peptidomic properties. Compared with pea protein isolate, PPH showed lower surface hydrophobicity, and moderate antioxidant activity. Peptidomic analysis identified 1740 peptides in the active hydrolysate. Combined in silico screening and in vitro validation further identified three peptides, GFSL, WFE, and FGF, as effective PL inhibitors, with IC₅₀ values of 337.81 ± 17.32, 473.32 ± 19.61, and 689.45 ± 39.32 μM, respectively. Molecular simulations indicated that these peptides interact with the catalytic pocket of PL mainly through hydrophobic interactions, van der Waals forces, and hydrogen bonding, with Ile79 serving as a key residue for peptide recognition. Overall, these findings indicate the potential of pea-derived peptides as natural PL inhibitors and support their application as functional food ingredients for modulating lipid digestion. Full article