Intermolecular Interaction Mechanism Research Articles

Investigating the impact of beeswax addition and diacylglycerol profiles on bigel properties and application in bread: insights on intermolecular interaction mechanisms

This study investigates the development of diacylglycerol (DAG)-based bigels as a healthier substitute for baking oil by combining hydroxypropyl methyl cellulose (HPMC)-based hydrogel with beeswax (BW)-based oleogel. Results indicated that increasing the concentration of BW enhances the interpenetration ability between the oleogel and hydrogel, leading to the formation of a stable bi-continuous bigel, as well as improved gel properties and thermal stability. The lipid profiles revealed that DAG's fatty acid composition could result in higher viscosity (0.075 ± 0.00 Pa.s) and lower interfacial equilibrium ability (14.02 ± 0.23 mN/m) compared to triglycerides (TAG). These characteristics contributed to enhanced mechanical properties and the maintenance of oil-water interface stability in the bigel. Spectroscopy and molecular dynamics simulations demonstrated that the DAG-based bigel could exhibit stronger van der Waals forces and hydrogen bonding between molecules compared to the TAG-based bigel. Consequently, DAG-based bigels showed superior gel properties and stability. Furthermore, textural analyses and sensory evaluations indicated that replacing 50% of butter with the DAG-based bigel in bread does not significantly alter the product compared to using 100% butter. This study underscores the potential of DAG in the preparation of bigels, promoting their application as the fat substitutes.

Insight into the degradation mechanism of mixed VOCs oxidation over Pd/UiO-66(Ce) catalysts: Combination of operando spectroscopy and theoretical calculation

Herein, Pd/UiO-66(Ce) catalysts were successfully synthesized by N2H4, H2, and NaBH4 reduction methods with UiO-66(Ce) as support. The best catalyst was selected via utilizing o-xylene as the probe molecule, and its degradation performance of mixed VOCs was further investigated. It was found that the reduction methods greatly influenced the size of Pd nanoparticles, the state of surface Pd, and the support structure in the catalysts, which in turn affected their catalytic performance. Among them, Pd/UiO-66(Ce)-Na exhibited the best o-xylene degradation activity (T90 = 192 °C) due to its smaller average Pd particle size (Pd Average = 2.93 nm) and higher surface Pd0 content (Pd0/Pdtotal = 0.79). The performance and interaction of Pd/UiO-66(Ce)-Na catalyst for degradation of mixed VOCs (o-xylene and toluene/benzene) were investigated by DFT adsorption energy calculation, in situ DRIFTS and GC–MS. Results suggested that the single adsorption energy of o-xylene was −1.20 eV, while in the system with toluene/benzene, the adsorption energy decreased to −0.78 and −0.6 eV, respectively. This showed the competitive adsorption effect between benzene and o-xylene was stronger than that between benzene and o-xylene. Finally, combined with in situ DRIFTS and GC–MS, the degradation path of mixed components was analyzed and studied systematically, and the mechanism of intermolecular interaction of benzene in the degradation process of mixed components was further revealed.

TYPES OF INTERMOLECULAR INTERACTIONS AND THEIR MODERN PHYSICAL SIGNIFICANCE

This article examines the important factors of intermolecular interactions to study the basic properties and physical nature of substances. Various optical methods have been used to study the nature and mechanism of intermolecular interactions. The properties of substances are revealed in detail, what molecules it consists of and how these molecules are located in relation to each other.

Development of a competitive array for discriminative determination of amphenicols in egg based on ribosomal protein L16

Abstract Object The amphenicols (chloramphenicol, thiamphenicol and florfenicol) can cause aplastic anaemia and other severe side effects to the consumers, so it is very necessary to inspect their residues in foods of animal origin. However, there has been no paper reporting the use of amphenicols receptor for the determination of their residues, and all the previously reported immunoassays for amphenicols can not differentiate the specific species. Materials and Methods In this study, the ribosomal protein L16 of Escherichia coli was first expressed, and its intermolecular interaction mechanisms with the three amphenicols were studied by using molecular docking technique. Then the protein was combined with three enzyme labeled conjugates to develop a direct competitive array on microplate for determination of the three drugs in egg. Results Due to the use of principal component analysis to analyze the data, this method could discriminate the three drugs in the range of 0.1-10 ng/mL, and the limits of detection for the three drugs were in the range of 0.0002-0.0009 ng/mL. The analysis results for the unknown egg samples were consistent with a liquid chromatography tandem mass spectrometry method, and the method performances were superior to the previous immunoassays for amphenicols. Conclusion This is the first paper reporting the use of ribosomal protein L16 to develop a competitive array for discriminative determination of amphenicols in food sample.

The structural evolution of CL-20-based energetic host–guest solvates at decomposition temperature according to the perceptions of THz spectroscopy

This work employed variable-temperature THz spectroscopy to analyze the structural evolution of host–guest energetic CL-20/H2O2 and CL-20/H2O solvates, as well as the mechanism of intermolecular interactions using DFT calculation and MD simulation.

METTL16 participates in haemoglobin H disease through m6A modification.

Haemoglobin H (HbH) disease is caused by a disorder of α-globin synthesis, and it results in a wide range of clinical symptoms. M6A methylation modification may be one of the mechanisms of heterogeneity. Therefore, this article explored the role of methyltransferase like 16 (METTL16) in HbH disease. The results of epigenetic transcriptome microarray were analysed and verified through bioinformatic methods and qRT-PCR, respectively. The overexpression or knock down of METTL16 in K562 cells was examined to determine its role in reactive oxygen species (ROS), cell cycle processes or iron overload. YTH domain family protein 3 (YTHDF3) was knocked down in K562 cells and K562 cells overexpressing METTL16 via siRNA to investigate its function. In addition, haemoglobin expression was detected through benzidine staining. qRT-PCR, WB, methylated RNA Immunoprecipitation (MeRIP) and (RNA Immunoprecipitation) RIP experiments were conducted to explore the mechanism of intermolecular interaction. METTL16, YTHDF3 and solute carrier family 5 member 3 (SLC5A3) mRNA and the methylation level of SLC5A3 mRNA were downregulated in HbH patients. Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) mRNA expression was negatively correlated with HGB content among patients with HbH-CS disease. Overexpression of METTL16 increased ROS and intracellular iron contents in K562 cells, changed the K562 cell cycle, reduced hemin-induced haemoglobin synthesis, increased the expressions of SLC5A3 and HBG and increased SLC5A3 mRNA methylation levels. Knockdown of METTL16 reduced ROS and intracellular iron contents in K562 cells. Hemin treatment of K562 cells for more than 14 days reduced the protein expressions of METTL16 and SLC5A3 and SLC5A3 mRNA methylation levels. Knockdown of YTHDF3 rescued the intracellular iron content changes induced by the overexpression of METTL16. The RIP experiment revealed that SLC5A3 mRNA can be enriched by METTL16 antibody. METTL16 may affect the expression of SLC5A3 by changing its m6A modification level and regulating ROS synthesis, intracellular iron and cycle of red blood cells. Moreover, METTL16 possibly affects the expression of haemoglobin through IGF2BP3, which regulates the clinical phenotype of HbH disease.

Production of AmpC β-Lactamase and Development of a Competitive Array for Discriminative Determination of Cephalosporins in Milk.

In this study, AmpC β-lactamase of Escherichia coli was expressed, and its intermolecular interaction mechanisms with 15 cephalosporins (CPs) were studied by using a molecular docking technique. Results showed that this enzyme mainly interacted with the β-lactam ring of these CPs, and the key contacting amino acids were Ser80 and Ser228. The AmpC β-lactamase was combined with 5 horseradish peroxidase-labeled conjugates to develop a direct competitive array on a microplate for determination of 15 drugs in milk. Due to the use of principal component analysis method to analyze the data, this method could discriminate the 15 drugs at the concentration as low as 10 ng/mL. The detection results for the unknown milk samples were consistent with those obtained by the liquid chromatography-mass spectrometry method. As a general comparison, this method is better than the previous antibody-based and receptor-based detection methods for CPs. This is the first paper reporting a competitive array for discriminative determination of a class of small-molecule substances.

Amylose complexation with diacylglycerols involves multiple intermolecular interaction mechanisms

Molecular complexation mediated by amylose can delay the oxidation of diacylglycerol (DAG) but the mechanism remains unclear, and little attention has been paid to starch–DAG complexes (SDCs). Herein, SDCs with different chain lengths (12−18 carbons) were prepared via co-precipitation and the underlying complexation mechanism was comprehensively explored. The results revealed nano-scale (∼150−500 nm) features and fewer weakly bound DAGs of SDCs with increasing chain length, attributed to complicated interchain and/or intrachain crosslinking with complexing indices ranging from 73% to 91%. X-ray diffraction, differential scanning calorimetry and thermogravimetry analysis unveiled the involvement of tight and weak intermolecular interaction mechanisms between starch and DAGs, and the former exhibited higher short-range structure order, confirmed by Fourier transform infrared spectroscopy and Raman spectroscopy. Molecular dynamics simulation showed that amylose tended to form V6-type helices around dimyristoyl- and distearoyl-glycerol with average helical cavity sizes of 9.4 and 11.3 Å, respectively, predominantly driven by hydrophobic interactions. SDCs significantly enhanced the oxidative stability of DAGs and delayed the in vitro starch digestion rate. The findings provide a paradigm for the intensive processing of DAGs to improve their oxidative stability and health-promoting efficacy.

TRAF Family Member 4 Promotes Cardiac Hypertrophy Through the Activation of the AKT Pathway.

Background Pathological cardiac hypertrophy is a major cause of heart failure morbidity. The complex mechanism of intermolecular interactions underlying the pathogenesis of cardiac hypertrophy has led to a lack of development and application of therapeutic methods. Methods and Results Our study provides the first evidence that TRAF4, a member of the tumor necrosis factor receptor-associated factor (TRAF) family, acts as a promoter of cardiac hypertrophy. Here, Western blotting assays demonstrated that TRAF4 is upregulated in cardiac hypertrophy. Additionally, TRAF4 deletion inhibits the development of cardiac hypertrophy in a mouse model after transverse aortic constriction surgery, whereas its overexpression promotes phenylephrine stimulation-induced cardiomyocyte hypertrophy in primary neonatal rat cardiomyocytes. Mechanistically, RNA-seq analysis revealed that TRAF4 promoted the activation of the protein kinase B pathway during cardiac hypertrophy. Moreover, we found that inhibition of protein kinase B phosphorylation rescued the aggravated cardiomyocyte hypertrophic phenotypes caused by TRAF4 overexpression in phenylephrine-treated neonatal rat cardiomyocytes, suggesting that TRAF4 may regulate cardiac hypertrophy in a protein kinase B-dependent manner. Conclusions Our results revealed the regulatory function of TRAF4 in cardiac hypertrophy, which may provide new insights into developing therapeutic and preventive targets for this disease.

More simple, efficient and accurate food research promoted by intermolecular interaction approaches: A review

The investigation of intermolecular interactions has become increasingly important in many studies, mainly by combining different analytical approaches to reveal the molecular mechanisms behind specific experimental phenomena. From spectroscopic analysis to sophisticated molecular simulation techniques like molecular docking, molecular dynamics (MD) simulation, and quantum chemical calculations (QCC), the mechanisms of intermolecular interactions are gradually being characterized more clearly and accurately, leading to revolutionary advances. This article aims to review the progression in the main techniques involving intermolecular interactions in food research and the corresponding experimental results. Finally, we discuss the significant impact that cutting-edge molecular simulation technologies may have on the future of conducting deeper exploration. Applications of molecular simulation technology may revolutionize the food research, making it possible to design new future foods with precise nutrition and desired properties.

A new correlation model of entrainer properties and process economics for ternary azeotrope separation by extractive distillation

A correlation model was explored and established for the first time, linking the properties of entrainers to the process economics of extractive distillation separation for ternary azeotropes. Firstly, the extraction process of ternary azeotrope (methyl tert-butyl ether/ethanol (EtOH)/water) with common entrainers was optimized using a multi-objective optimization method based on a genetic algorithm. The optimal process parameters were obtained, and dimethyl sulfolone emerged as the best entrainer for the system. An economic correlation model was developed using machine learning to link the properties of entrainers and total annual cost (TAC). The model exhibited a determination coefficient of 0.993 and a single percentage error of less than 2% for each data set, indicating a significant fitting degree and prediction accuracy. The feasibility of selecting the optimal entrainer and calculating the economic benefit of the model was verified through another ternary azeotrope system (i.e., tetrahydrofuran/EtOH/water). The model provides valuable insights into energy savings and entrainer screening in extractive distillation. Additionally, the influence of the heat integration process with different entrainers on the economic benefit was analyzed, and the optimum entrainer changed to glycerol after the heat integration process. This finding suggests that determining the optimum entrainer should consider the possible heat integration process design. Finally, the relationship between the intermolecular interaction mechanism and separation effect was revealed through quantum chemical calculations.

Investigating the Molecular Rearrangement of Polar Liquid Mixtures Using Terahertz Frequency Domain Reflection Spectroscopy.

A special data processing method for the terahertz frequency domain reflection spectroscopy system has been proposed to analyze the characteristics of a polar mixed liquid. This novel and practical measurement system is characterized by a simpler optical structure and a tunable output frequency range of 0.1-1 THz. By Hilbert transform, stationary wavelet transform, and time domain zero setting method, the reflection coefficient that has been eliminated by the noise and the Fabry-Pérot effect can be obtained by the self-reference calibration method. Then, the dielectric function of the ethanol/n-hexane and propanol/n-hexane mixtures with different mixture ratios can be extracted by this method. In addition, a significant deviation can be observed between the imaginary part of the measured dielectric function and the ideal calculated value. These results indicate that during the mixing process of polar and nonpolar liquids, the hydroxyl functional groups of alcohols significantly change the molecular arrangement pattern of the mixture. The arrangement pattern will result in the formation of the new permanent dipole moment. This study lays a solid foundation for future research on the microscopic mechanism of intermolecular interaction using terahertz frequency domain reflection spectroscopy.

A multifunctional and sustainable poly(ionic liquid)-quaternized chitosan hydrogel with thermal-triggered reversible adhesion

A quaternized chitosan (QCS)@poly(ionic liquid) (PIL) hydrogel adhesive was prepared by in-situ ultraviolet (UV)-induced copolymerization of 1-vinyl-3-butyl imidazolium bromide ([BVIm][Br]) and methacryloyloxyethyl trimethylammonium chloride (DMC) in QCS aqueous solution without using any crosslinkers, which was stably crosslinked by reversible hydrogen bonding together with ion association and exhibited excellent adhesion, plasticity, conductivity and recyclability properties. Moreover, its thermal/pH-responsive behaviors and intermolecular interaction mechanism of thermal-triggered reversible adhesion were discovered, meanwhile good biocompatibility, antibacterial properties, repeated stickiness and degradability were also proved. The results showed that the newly developed hydrogel could make various tissues, organic, inorganic or metal materials adhered tightly within 1 min; after 10 binding-peeling cycles, the adhesive strength to glass, plastic, aluminum and porcine skin still remained beyond 96 %, 98 %, 92 % and 71 % of the original, respectively. The adhesion mechanism involves ion dipole interaction, electrostatic interaction, hydrophobic interaction, coordination, cation-π interaction, H-bonding and van der Waals force. For above merits, the new tricomponent hydrogel is expected to be applied in biomedical field to achieve adjustable adhesion and on-demand peeling.

Magnetic Ionotropic Hydrogels Based on Carboxymethyl Cellulose for Aqueous Pollution Mitigation

In this work, stabilized ionotropic hydrogels were designed using sodium carboxymethyl cellulose (CMC) and assessed as inexpensive sorbents for hazardous chemicals (e.g., Methylene Blue, MB) from contaminated wastewaters. In order to increase the adsorption capacity of the hydrogelated matrix and facilitate its magnetic separation from aqueous solutions, sodium dodecyl sulfate (SDS) and manganese ferrite (MnFe2O4) were introduced into the polymer framework. The morphological, structural, elemental, and magnetic properties of the adsorbents (in the form of beads) were assessed using scanning electron microscopy (SEM), energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy (FTIR), and a vibrating-sample magnetometer (VSM). The magnetic beads with the best adsorption performance were subjected to kinetic and isotherm studies. The PFO model best describes the adsorption kinetics. A homogeneous monolayer adsorption system was predicted by the Langmuir isotherm model, registering a maximum adsorption capacity of 234 mg/g at 300 K. The calculated thermodynamic parameter values indicated that the investigated adsorption processes were both spontaneous (ΔG < 0) and exothermic (ΔH < 0). The used sorbent can be recovered after immersion in acetone (93% desorption efficiency) and re-used for MB adsorption. In addition, the molecular docking simulations disclosed aspects of the mechanism of intermolecular interaction between CMC and MB by detailing the contributions of the van der Waals (physical) and Coulomb (electrostatic) forces.

Спектральные проявления механизмов межмолекулярного взаимодействия модифицированных малеимидом полиэлектролитных капсул, используемых в таргетной терапии

Mechanisms of intermolecular interaction between components of polyelectrolyte target delivery capsules and maleimide, which enhances the therapeutic action of the capsule, are investigated by quantum chemical modeling methods based on Density Functional Theory (DFT). Molecules of polymer polyelectrolyte capsule components - polyarginine and dextran sulfate and maleimide molecule are investigated. Based on calculation of molecular complexes structures and corresponding IR spectra with analysis of formed hydrogen bonds parameters it was revealed that there was a strong enough hydrogen bonding between maleimide and arginine, included in capsule composition. This allows us to conclude that modification of arginine with maleimide promotes stronger hydrogen bonding with amino acids contained in human body, which is confirmed by calculations, and gives the possibility of using maleimide as an "anchor" to hold the capsule in the tissue.

Kidney Tubules — Scientific and Applied Value

Currently, there is a high scientific interest in studying the features of the structure and functions of the tubules of the kidneys. The relevance of the topic is due to the potential possibility of identifying various markers of tubular dysfunction and using them for early diagnosis of not only tubulopathies, but also glomerular disorders. In clinical practice, markers of tubular dysfunction are used insufficiently. The article presents information about the anatomical and functional features of the proximal and distal parts of the tubular apparatus, outlines highly organized mechanisms of intermolecular interaction, presents the main biologically active substances, the change in the concentration of which is a consequence of damage to the tubules. The presented manuscript is the product of a deep analysis and systematization of the available data in Russian and foreign information and analytical portals.

Luminous Self-Assembled Fibers of Azopyridines and Quantum Dots Enabled by Synergy of Halogen Bond and Alkyl Chain Interactions

Herein, a simple approach for the fabrication of luminous self-assembled fibers based on halogen-bonded azopyridine complexes and oleic acid-modified quantum dots (QDs) is reported. The QDs uniformly align on the edge of the self-assembled fibers through the formation of van der Waals force between the alkyl chain of oleic acid on the QD surface and the alkyl chain of the halogen-bonded complexes, 15Br or 15I. Furthermore, the intermolecular interaction mechanism was elucidated by using Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and density functional theory (DFT) calculations. This approach results in retention of the fluorescence properties of the QDs in the fibers. In addition, the bromine-bonded fibers can be assembled into tailored directional fibers upon evaporation of the solvent (tetrahydrofuran) when using capillaries via the capillary force. Interestingly, the mesogenic properties of the halogen-bonded complexes are preserved in the easily prepared halogen-bonded fluorescent fibers; this provides new insight into the design of functional self-assembly materials.

PVA/PEO/PVA-g-APEG nanofiber membranes with cytocompatibility and anti-cell adhesion for biomedical applications

To prepare novel medical dressings with excellent comprehensive properties, this work uses the polyvinyl alcohol-allyl polyethylene glycol graft copolymer (PVA-g-APEG) synthesized in our previous work as a modifier. The polyvinyl alcohol (PVA)/polyethylene oxide (PEO)/PVA-g-APEG nanofiber membranes with different PVA-g-APEG contents are successfully prepared by electrospinning technology. The biomimetic natural extracellular matrix structure of nanofiber membranes is achieved by regulating the PVA-g-APEG contents. As the content of PVA-g-APEG is 4 wt%, the diameter distribution of nanofibers is the narrowest. The average diameter of nanofibers reaches the minimum value of 267.18 nm, and the porosity of nanofiber membranes reaches the maximum value of 77.90%. Meanwhile, nanofiber membranes possess excellent biocompatibility. The absorption capacity of the nanofiber membranes for different liquids is improved with higher PVA-g-APEG content. The nanofiber membranes become soft and slippery after contact with liquid, effectively avoiding adhesion with cells. The cell proliferation rate is higher than 100%, and the cytotoxicity grade is 0. Additionally, the mechanisms of intermolecular interactions, crystallization and mechanical properties change of nanofiber membranes are discussed systematically. It provides a method and idea for preparing high-strength PVA/PEO nanofiber membranes and realizing the practical application of PVA/PEO composite systems in medical dressings.

Insights into Molecular Mechanisms of EGCG and Apigenin on Disrupting Amyloid-Beta Protofibrils Based on Molecular Dynamics Simulations.

The fibrillization and deposition of amyloid-beta (Aβ) protofibrils are one of the important factors leading to Alzheimer's disease. Molecular dynamics simulations can offer information on intermolecular interaction mechanisms between Aβ protofibrils and Aβ fibrillization inhibitors. Here, in this work, we explore the early molecular mechanisms of (-)-epigallocatechin-3-gallate (EGCG) and apigenin on disrupting Aβ42 protofibrils based on molecular simulations. The binding modes of EGCG and apigenin with the Aβ42 protofibril are obtained. Furthermore, we compare the behavioral mechanisms of EGCG and apigenin on disturbing the Aβ42 protofibril. Both EGCG and apigenin are able to decrease the proportion of the β-sheet and bend structures of the Aβ42 protofibril while inducing random coil structures. The results of hydrogen bonds and D23-K28 salt bridges illustrate that EGCG and apigenin have the ability of destabilizing the Aβ42 protofibril. Meanwhile, the van der Waals interactions between the EGCG and Aβ42 protofibril are shown to be larger than that of apigenin with the Aβ42 protofibril, but the electrostatic interactions between apigenin and the Aβ42 protofibril are dominant in the binding affinity. Our findings may help in designing effective drug candidates for disordering the Aβ protofibril and impeding Aβ fibrillization.

Physical mechanisms of intermolecular interactions from symmetry-adapted perturbation theory.

Symmetry-adapted perturbation theory (SAPT) is a method for computational studies of noncovalent interactions between molecules. This method will be discussed here from the perspective of establishing the paradigm for understanding mechanisms of intermolecular interactions. SAPT interaction energies are obtained as sums of several contributions. Each contribution possesses a clear physical interpretation as it results from some specific physical process. It also exhibits a specific dependence on the intermolecularseparationR. The four major contributions are the electrostatic, induction, dispersion, and exchange energies, each due to a different mechanism, valid at anyR. In addition, at large R, SAPT interaction energies are seamlessly connected with the corresponding terms in the asymptotic multipole expansion of interaction energy in inverse powers of R. Since such expansion explicitly depends on monomers' multipole moments and polarizabilities, this connection provides additional insights by rigorously relating interaction energies to monomers' properties.