Search Results (1,103)

A promising direction for the creation of new biologically active derivatives of the alkaloid lupinine is the synthesis of “hybrid molecules” that combine a fragment of the alkaloid and the pharmacophore of 1,2,3-triazole in their structure. From a biological perspective, this work presents the first X-ray diffraction study of a single crystal of (1S,9aR)-1-({4-[4-(Benzyloxy)-3-methoxyphenyl]-1H-1,2,3-triazol-1-yl}methyl)octahydro-2H-quinolizine, a new, recently synthesized 1,2,3-triazole derivative of lupinine. A comparison of theoretically predicted and experimentally observed structural parameters was carried out. The FTIR spectroscopy study and vibrational properties calculations allowed us to interpret the FTIR absorption spectrum and localize specific vibrational modes in quinolizidine, 1,2,3-triazole, and benzene rings. Such information can be fruitful for further characterization of the synthesis process and products. The molecular docking of the compound was performed. It was shown that the studied molecules are capable of interacting with the Mpro binding site via non-covalent and hydrophobic interactions with subsites S3 (Met165, Glu166, Leu167, Pro168) and S5 (Gln189, Thr190, Gln192), which ensure the stabilization of the Mpro substrate. Blocking of the active site of the enzyme in the region of the oxyanion hole does not occur, but stable stacking interactions with the π-system of one of the catalytic amino acids, His41, are observed. Full article

Background: Aggregatibacter actinomycetemcomitans is a Gram-negative, facultative anaerobic, immobile oral bacterium responsible for the secretion of virulence factors, namely leukotoxin (LtxA), a large exotoxin of the RTX family that enables the bacterium to evade the immune system by destroying leukocytes, resulting in aggressive periodontitis (AP) leading to tooth loss. Methods: This study aimed to screen 106 molecules derived from Moroccan propolis in order to identify potential inhibitors of the active sites of LtxA based on molecular docking, ADMET property evaluation, and molecular dynamics (MD) simulation. Results: Epigallocatechin gallate (EGCg), used as a reference compound, showed binding energies of −6.9 kcal/mol, −6.1 kcal/mol, −6.5 kcal/mol, and −5.9 kcal/mol with the four active sites P1, P2, P3, and P4, respectively. By establishing conventional hydrogen bonds, pi-alkyl bonds, and non-covalent pi–pi bonds. Chrysin and luteolin showed favorable binding affinities with the four active sites, named as follows: P1–P4 (P1–chrysin = −7.5 kcal/mol; P2–chrysin = −7.9 kcal/mol; P3–chrysin = −8.1 kcal/mol; P4–chrysin = −6.9 kcal/mol; P1–luteolin = −7.3 kcal/mol; P2–luteolin = −7.6 kcal/mol; P3–luteolin = −8.1 kcal/mol; P4–luteolin = −7.3 kcal/mol). The binding affinity of these two propolis derivatives was stabilized by pi−sigma bonds, pi−alkyl bonds, conventional hydrogen bonds, pi-cation interactions, non-covalent pi–pi bonds, and carbon–hydrogen bonds. According to free energy calculations performed with Prime MM-GBSA, the complexes formed by chrysin demonstrated the most stable interactions due to Van der Waals and lipophilic forces. Luteolin formed significant interactions, but slightly weaker than those of chrysin. These results reveal the inhibitory potential of chrysin and luteolin with protein active sites. MD simulations corroborated the excellent stability of complexes formed by chrysin, as indicated by low RMSD values, suggesting favorable dynamic behavior. Conclusions: These results highlight the potential of chrysin as a versatile inhibitor capable of interacting with the four active sites. These findings are a strong foundation for further experimental confirmations. Full article

This computational study investigates the thermal decomposition of 1,2,4-triazol-3(2H)-ones and their thione analogues using Density Functional Theory (DFT). The reaction proceeds via a concerted, six-membered cyclic transition state, primarily driven by the breaking of the N–N bond. A key finding is that the accuracy of the calculated activation energies (Ea) strongly depends on the choice of DFT functional. For sulfur-containing systems (thiones), the hybrid functional APFD (with 25% Hartree–Fock exchange) provides the most reliable results, effectively describing their higher polarizability. In contrast, for oxygen-containing systems (triazolones), the dispersion-corrected functional B97D-GD3BJ (with 0% Hartree–Fock exchange) delivers superior accuracy by better modeling electrostatic and dispersion interactions. The -CH₂CH₂CN group at the N-2 position acts not only as a protecting group but also stabilizes the transition state through non-covalent interactions. Electron-withdrawing substituents slightly increase the E_a, while electron-donating groups decrease it. Sulfur analogues consistently show significantly lower activation energies (by ~40 kJ/mol) than their oxygen counterparts, explaining their experimentally observed faster decomposition. This work establishes a dual-methodology computational framework for accurately predicting the kinetics of these reactions, providing valuable insights for the regioselective synthesis of biologically relevant triazole derivatives via controlled pyrolysis. Full article

Temperature-responsive hydrogels are sophisticated stimuli-responsive biomaterials that undergo rapid, reversible sol–gel phase transitions in response to subtle thermal stimuli, most notably around physiological temperature. This inherent thermosensitivity enables non-invasive, precise spatiotemporal control of material properties and bioactive payload release, rendering them highly promising for advanced biomedical applications. This review critically surveys recent advances in the design, synthesis, and translational potential of thermo-responsive hydrogels, emphasizing nanoscale and hybrid architectures optimized for superior tunability and biological performance. Foundational systems remain dominated by poly(N-isopropylacrylamide) (PNIPAAm), which exhibits a sharp lower critical solution temperature near 32 °C, alongside Pluronic/Poloxamer triblock copolymers and thermosensitive cellulose derivatives. Contemporary developments increasingly exploit biohybrid and nanocomposite strategies that incorporate natural polymers such as chitosan, gelatin, or hyaluronic acid with synthetic thermo-responsive segments, yielding materials with markedly enhanced mechanical robustness, biocompatibility, and physiologically relevant transition behavior. Cross-linking methodologies—encompassing covalent chemical approaches, dynamic physical interactions, and radiation-induced polymerization are rigorously assessed for their effects on network topology, swelling/deswelling kinetics, pore structure, and degradation characteristics. Prominent applications include on-demand drug and gene delivery, injectable in situ gelling systems, three-dimensional matrices for cell encapsulation and organoid culture, tissue engineering scaffolds, self-healing wound dressings, and responsive biosensing platforms. The integration of multi-stimuli orthogonality, nanotechnology, and artificial intelligence-guided materials discovery is anticipated to deliver fully programmable, patient-specific hydrogels, establishing them as pivotal enabling technologies in precision and regenerative medicine. Full article

Biodegradable starch-based films often suffer from insufficient mechanical strength, which limits their practical applications. To enhance film performance, this study optimized the preparation of composite thermoplastic starch (CTPS) films composed of corn starch, sorbitol, whey protein isolate (WPI), and gallic acid (GA). The optimized formulation—0.074 g/mL corn starch, 47.5% sorbitol, 5.6% WPI, and 2.0 mg/mL GA—yielded films with a tensile strength of 3.11 ± 0.31 MPa and an elongation at break of 43.35 ± 0.69%, achieving a desirable balance between flexibility and strength. Mechanistic investigations using in situ Fourier-transform infrared spectroscopy (FTIR), low-field nuclear magnetic resonance (LF-NMR), confocal laser scanning microscopy (CLSM), and molecular docking revealed a ternary interaction system among starch, WPI, and GA. These components primarily interacted through hydrogen bonding and van der Waals forces. Such non-covalent interactions enhanced the short-range molecular ordering of the starch matrix, stabilized the secondary structure of WPI, and facilitated water redistribution during film formation. The resulting interaction network among starch, proteins, and polyphenols significantly improved the mechanical properties and antioxidant capacity of the CTPS films. Full article

The rhenium(I) tricarbonyl complex fac-[Re(CO)₃(5,6-epoxy-5,6-dihydro-1,10-phenanthroline)Br] (ReL) has previously demonstrated promising luminescent properties, enabling its direct application as a probe for walled cells such as Candida albicans and Salmonella enterica. In this new study, we present a significantly expanded and comprehensive characterization of ReL, incorporating a wide range of experimental and computational techniques not previously reported. These include variable-temperature ¹H and ¹³C NMR spectroscopy, CH-COSY, single-crystal X-ray diffraction, Hirshfeld surface analysis, DFT calculations, Fukui functions, non-covalent interaction (NCI) indices, and electrochemical profiling. Structural analysis confirmed a pseudo-octahedral geometry with the bromide ligand positioned cis to the epoxy group. NMR data revealed the coexistence of cis and trans isomers in solution, with the trans form being slightly more stable. DFT calculations and aromaticity descriptors indicated minimal electronic differences between isomers, supporting their unified treatment in subsequent analyses. Electrochemical studies revealed two oxidation and two reduction events, consistent with ECE and EEC mechanisms, including a Re(I) → Re(0) transition at −1.50 V vs. SCE. Theoretical redox potentials showed strong agreement with experimental data. Biological assays revealed a dose-dependent cytotoxic effect on HeLa cells, contrasting with previously reported low toxicity in microbial systems. These findings, combined with ReL’s luminescent and antimicrobial properties, underscore its multifunctional nature and highlight its potential as a bioactive and imaging agent for advanced therapeutic and microbiological applications. Full article

Non-covalent contacts play a significant role in binding between fragments in supramolecular assemblies. Understanding the non-covalent binding capabilities of closo-borate anions and their derivatives is a significant research challenge, due to their ability to interact with biomolecules. The present work was focused on the theoretical study of non-covalent complexes between glycine and closo-borate anions [B_nH_n−1X]^y− (X = H, NH₃, OH, SH, F; n = 10, 12; y = 1, 2). The main binding patterns between glycine and cluster systems were defined, and the effect of the exo-polyhedral substituent on the stability of non-covalent complexes was analysed. Complexes based on ammonium and hydroxy derivatives of closo-borate anions [B_nH_n−1X]^y− (X = NH₃, OH; n = 10, 12; y = 1, 2) were the most stable among all the derivatives considered. The findings of this work can be applied to the design of non-covalent complexes of closo-borate systems with biomolecules. Full article

Background: Rapidly growing mycobacteria (RGM) are microorganisms with variable pathogenicity, which can cause different clinical forms of mycobacterioses. They can form structured communities at the liquid-air interface and adhere to animate and inanimate solid surfaces, characterizing one of their most powerful mechanisms of resistance and survival, named biofilms. Objectives: Here, a novel series of sulfamethoxazole (SMTZ) Schiff bases were obtained by the condensation of the primary amine from SMTZ core with six different aldehydes to evaluate their antimicrobial and antibiofilm activities, as well as physicochemical and in silico characteristics. Methods: The compounds L1–L6 included: pyridoxal hydrochloride (L1), salicylaldehyde (L2), 3-methoxysalicylaldehyde (L3), 2-hydroxy-1-naphthaldehyde (L4), 3-allylsalicylaldehyde (L5), and 4-(diethylamino)salicylaldehyde (L6). MIC determination was performed against standard strains and seven clinical isolates. Time-kill assays, biofilm inhibition assays, atomic force microscopy, and peripheral blood mononuclear cell cytotoxicity assays were carried out. Density functional theory (DFT) calculations using quantum descriptors, Mulliken charges, Fukui functions, non-covalent interactions (NCI), and reduced density gradient (RDG), along with molecular docking calculations to DHS, LasR, and PqsR, supported the experimental trend. Results: The compounds L1–L6 showed a significant capacity to inhibit the growth of RGM, with MIC values in the range of 0.61 to 1.22 μg mL⁻¹, which are significantly lower than those observed for the parent compound SMTZ, demonstrating superior antimicrobial potency. To deepen antimicrobial activity assays, L1 was chosen for further evaluations and showed a significant ability to inhibit the growth of RGM in both planktonic and biofilm forms. In addition, atomic force microscopy views great changes in topography, electrical force, and nanomechanical properties of microorganisms. The cytotoxic assays with the peripheral blood mononuclear cell model suggest that the new compound may be considered as an antimicrobial alternative, as well as a safe substance showing selectivity indexes in the range of efficacy. Conclusions: Density functional theory (DFT) calculations were performed to obtain quantum descriptors, Mulliken charges, Fukui functions, non-covalent interactions (NCI), and reduced density gradient (RDG), which, with molecular docking calculations to DHS, LasR, and PqsR, supported the experimental trend. Full article

This study investigated the effects of tamarind seed polysaccharide (TSP) on the structural characteristics, digestibility, and emulsifying properties of waxy maize starch (WMS), as well as their interaction mechanisms. WMS-TSP complexes were prepared via complexes to improve starch’s physical and functional properties. Native WMS showed smooth spherical granules, while WMS-TSP samples formed freeze-drying-induced honeycomb structures (~200–250 μm). In vitro digestion indicated that WMS-TSP systems (5–15%) reduced RDS by 20.1–24.11% relative to native WMS (41% ± SD), suggesting a potential to attenuate postprandial glycemic responses. Fourier-transform infrared (FT-IR) spectroscopy revealed that TSP interacted with WMS mainly through non-covalent bonds such as hydrogen bonding, while influencing the degree of crystallinity without generating new crystalline polymorphs. In corn oil-based emulsions, the WMS-TSP composites showed strong viscoelastic behavior, with elevated storage (G′) and loss (G″) moduli, together with improved storage stability. These findings highlight the synergistic potential of WMS and TSP in enhancing the functionality of starch-based systems and provide insights into the role of polysaccharides in food structure and digestion regulation. Full article

The study explores the impact of incorporating Polygonatum cyrtonema flour (PCF) into wheat flour on dough functionality and steamed bread quality. The results show that PCF enhanced dough hydration, rheology, and protein network stability through hydrophilic and non-covalent interactions, particularly hydrogen bonding. At the optimal level, steamed bread demonstrates improved specific volume, elasticity, and cohesiveness, accompanied by reduced hardness and chewiness, with hardness decreasing by 29%, chewiness by 25.80%, and gumminess by 26.30%. Microstructural analyses have confirmed enhanced water retention, strengthened gluten matrices, and favorable secondary structure transitions. The ultraviolet visible absorption spectroscopy and fluorescence spectroscopy analyses revealed that PCF enhanced the interactions between proteins and starch, accompanied by a red shift and decreased fluorescence intensity, indicating a more compact protein conformation. These findings suggest that PCF regulates protein secondary structures through hydrogen bonding and hydrophobic interactions, thereby stabilizing the gluten network. PCF supplementation boosted antioxidant activity and modulates starch digestibility; at a 10% substitution level, resistant starch (RS) decreases from approximately 60% in the control to 34%. This reduction indicates that PCF disrupts the integrity of the starch protein matrix, increasing amylase accessibility to starch granules and thus promoting starch hydrolysis. Incorporating 4% PCF in the formulation enhances both the technological performance and nutritional quality of the product while maintaining its overall integrity. These findings highlight the dual role of PCF in improving technological functionality and nutritional attributes. PCF emerges as a promising natural fortification ingredient for steamed bread, offering quality enhancement and additional health value. Full article

The anion, cation, and radical structural forms of B₂N ^(−,0,+) were studied in the case of symmetry breaking (SB) inside a (5, 5) BN nanotube ring and were also compared in terms of non-covalent interaction between these two parts. The non-bonded system of B₂N ^(−,0,+) and the (5, 5) BN nanotube not only causes SB for BNB but also creates an energy barrier in the range of 10⁻³ Hartree of due to this non-bonded interaction. Moreover, several SBs appear via asymmetry stretching and symmetry bending normal mode interactions according to the multiple second-order Jahn–Teller effect. We also demonstrated that the twin minimum of BNB’s potential curve arises from the lack of a proper wave function with permutation symmetry, as well as abnormal charge distribution. Through this investigation, considerable enhancements in the energy barriers due to the SB effect were also observed during the electrostatic interaction of BNB (both radical and cation) with the BN nanotube ring. Additionally, these values were not observed for the isolated B₂N ^(−,0,+) forms. This non-bonded complex operates as a quantum rotatory model and as a catalyst for producing a range of spectra in the IR region due to the alternative attraction and repulsion forces. Full article

Artificial neural networks in drug discovery have shown remarkable potential in various areas, including molecular similarity assessment and virtual screening. This study presents a novel multimodal Siamese neural network architecture. The aim was to join molecular electrostatic potential (MEP) images with the texture features derived from reduced density gradient (RDG) diagrams for enhanced molecular similarity prediction. On one side, the proposed model is combined with a convolutional neural network (CNN) for processing MEP visual information. This data is added to the multilayer perceptron (MLP) that extracts texture features from gray-level co-occurrence matrices (GLCM) computed from RDG diagrams. Both representations converge through a multimodal projector into a shared embedding space, which was trained using triplet loss to learn similarity and dissimilarity patterns. Limitations associated with the use of purely structural descriptors were overcome by incorporating non-covalent interaction information through RDG profiles, which enables the identification of bioisosteric relationships needed for rational drug design. Three datasets were used to evaluate the performance of the developed model: tyrosine kinase inhibitors (TKIs) targeting the mutant T315I BCR-ABL receptor for the treatment of chronic myeloid leukemia, acetylcholinesterase inhibitors (AChEIs) for Alzheimer’s disease therapy, and heterodimeric AChEI candidates for cross-validation. The visual and texture features of the Siamese architecture help in the capture of molecular similarities based on electrostatic and non-covalent interaction profiles. Therefore, the developed protocol offers a suitable approach in computational drug discovery, being a promising framework for virtual screening, drug repositioning, and the identification of novel therapeutic candidates. Full article

Geothermal energy, recognized as a sustainable and clean resource, is playing an increasingly critical role in the global shift toward low-carbon energy systems. Nevertheless, the exploitation of fractured geothermal reservoirs is often impeded by severe lost circulation during drilling, where conventional plugging materials fail under high-temperature, high-salinity, and high-pressure conditions due to inadequate mechanical strength, poor thermal resistance, and lack of self-adaptive sealing behavior. In response, self-healing materials have emerged as an innovative strategy for developing intelligent lost circulation control technologies. Herein, we report a novel self-healing gel (XFFD) synthesized via inverse emulsion polymerization using acrylamide (AM), acrylic acid (AA), p-nitroblue tetrazolium (PNBT), and modified silica nanoparticles (PAS). The resulting material exhibits exceptional thermal stability, with decomposition onset above 356 °C, as determined by thermogravimetric analysis. Rheological and mechanical assessments reveal outstanding viscoelasticity, moderate swelling capacity (4.17-fold in deionized water), and a high self-recovery efficiency of 91.15%, accompanied by a bearing strength of 3.65 MPa. Mechanistic investigations indicate that the autonomous repair capability stems from dynamic non-covalent interactions—primarily hydrogen bonding and ionic associations—enabled by amide and carboxyl groups within the polymer network. Sand bed filtration tests under simulated geothermal conditions (150 °C, 8% salinity) demonstrate that XFFD forms a robust sealing barrier with significantly shallower invasion depth compared to conventional materials such as sulfonated asphalt and calcium carbonate. This work presents an effective self-healing gel system that ensures reliable wellbore strengthening and fluid loss control in challenging high-temperature, high-salinity geothermal drilling operations. Full article

Milk coffee is a composite beverage in which interactions among dairy proteins, lipids, and coffee polyphenols govern flavor, texture, and stability. This review synthesizes recent research to guide formulation and processing, covering conventional Ultra-high temperature sterilization (UHT) and innovative routes including blending-after-sterilization (BAS), high-pressure homogenization (HPH), ultrasound/pulsed electric field (PEF)/cold plasma (CP), microencapsulation, and plant-based matrices. Key findings show that non-covalent protein–polyphenol complexes and interfacial partitioning at fat-globule membranes control volatile retention, astringency, droplet structure, and phenolic bioaccessibility; appropriate fat levels and HPH refine microstructure; BAS better preserves aroma; and matrix or decaffeination choices modulate antioxidant capacity. Guided by these insights, we propose a concise “process–activity–stability” framework linking parameters to functionality and shelf life to accelerate the development of high-quality, nutritious, enjoyable, and more sustainable milk coffee products. Full article

Leading-edge erosion (LEE) of wind-turbine blades, driven primarily by rain erosion, particulate erosion, and environmental ageing, remains one of the most pervasive causes of performance loss and maintenance cost in offshore and onshore wind farms. Self-healing coatings, which autonomously or semi-autonomously restore barriers and mechanical function after damage, promise a paradigm shift in blade protection by combining immediate impact resistance with in-service reparability. This review surveys the state of the art in self-healing coating technologies (intrinsic chemistries such as non-covalent interactions or dynamic covalent bonds; extrinsic systems including micro/nanocapsules and microvascular networks) and evaluates their suitability for anti-erosion, mechanical robustness, and multifunctional protection of leading edges. The outcomes of theoretical, experimental, modelling and field-oriented studies on the leading-edge protection and coating characterisation identify which self-healing concepts best meet the simultaneous requirements of toughness, adhesion, surface finish, and long-term durability of wind blade applications. Key gaps are highlighted, notably trade-offs between healing efficiency and mechanical toughness, challenges in large-area and sprayable application methods, and the need for standardised characterisation and testing of self-healing coating protocols. We propose a roadmap for targeted materials research, accelerated testing, and field trials. This review discusses recent studies to guide materials scientists and renewable-energy engineers toward promising routes to deployable, multifunctional, self-healing anti-erosion coatings, especially for wind-energy infrastructure. Full article