Polarizable Hydrogen Bonds Research Articles

Searching for the role of membrane lipids in the mechanism of antibacterial effect of hinokitiol

The aim of this work was to investigate the effect of monoterpenoid hinokitiol (β-thujaplicin) on the monolayers and bilayers composed of lipids typical for bacteria membranes and gain insight into the potential role of the lipids in antibacterial activity and selectivity of this compound. To explore this issue, the in vitro studies were performed on different bacterial strains to verify antibacterial potency of hinokitiol. Then, the experiments on E. coli and S. aureus bacteria membrane models (i.e. model multicomponent monolayers and bilayers) were done. Finally, the effect of hinokitiol on one component lipid monolayers was investigated. The lipids used in the experiments included Phosphatidylethanolamines (PEs), Phosphatidylglycerols (PGs) and Cardiolipins differing in the structure of the polar head and/or the hydrophobic chains. This choice allowed the analysis of correlations between the lipid structure and the effect of hinokitiol.In vitro tests confirmed the antimicrobial activity of hinokitiol against most of the strains tested. In addition, the in vitro tests showed that E. coli bacteria were more sensitive to hinokitiol than S. aureus bacteria. Interestingly, the studies on model systems evidenced that hinokitiol molecules are of stronger effect on E.coli film and they are able to insert into these systems even at membrane-related surface pressures. Moreover, the structure of the lipid and its content in the model system correlated with the effect exerted by hinokitiol on the monolayer properties. It was found that hinokitiol differs in the affinity to particular lipids and additionally hinokitiol/lipid interactions may occur according to different mechanisms. Namely, depending on the lipid structure, hinokitiol may incorporate into the lipid film (Cardiolipins and PEs) or interact preferentially with the lipid polar head (PGs) and form hydrogen bonds. The effect of hinokitiol on the lipids was determined by the charge and size of the polar head as well as by the spatial size of the lipid molecule. Moreover, comparing the lipids of the same polar heads, hinokitiol caused stronger expansion of the film formed from the lipid having unsaturated chains. The results obtained may explain the difference in the effect of hinokitiol on particular bacterial strains. In conclusions, it can be suggested that the lipids should be considered as the bacteria membrane structural elements of a possible role in the mechanism of action of hinokitiol.

Effect of anion α-functionalization on the water affinity of thermo-responsive phosphonium acetate-derived ionic liquids

This study presents a facile method for assessing the effect of anion functional group substitution on the water affinity of phosphonium-acetate ionic liquids. By combining the same cation with three different α-substituted carboxylate anions, the effect of anion functional group substitution on the IL miscibility with water and hygroscopicity was experimentally evaluated and rationalized using COSMO-RS sigma profile analysis. Lower critical solution temperature (LCST) phase separation experiments and water vapor partial pressure measurements revealed that there is a stark α-substitution dependency on the affinity of water for acetate [AcO], pivalate [PivO], and trifluoroacetate [TFA] derived tributyl(octyl)phosphonium [P4448] ILs. It was found that the IL water affinities varied as: [P4448][AcO] > [P4448][PivO] > [P4448][TFA]. With the lowest water partial pressure and no LCST driven phase separation, [P4448][AcO] exhibited a high affinity for water. On the other hand, [P4448][PivO] and [P4448][TFA] exhibited LCST-driven phase separation and room temperature immiscibility, respectively, with higher water partial pressures, as a result of relatively weak water affinities. COSMO-RS sigma profile analysis revealed that the aliphatic carboxylate anions should incorporate apolar interactions commensurate with or greater than the polar hydrogen bond acceptor interactions for phase immiscibility of the corresponding IL with water. It was found that the relative magnitudes of apolar and polar interactions, assessed using the anion sigma profile peak intensity ratio (Ir), are directly correlated with the IL water affinity, and inversely correlated with the solution water activity coefficient. Therefore, it was concluded that Ir forms a quantitative link between the structural changes at the molecular level and the bulk water affinity exhibited by the ionic liquid as a whole.

Dissolution dynamics of partially protected poly(4-hydroxystyrene) in organic developers investigated by a quartz crystal microbalance (QCM) method

Poly(4-hydroxystyrene) (PHS) molecules in solid films are connected to each other through polar and nonpolar molecular interaction and hydrogen bonds. Although the dissociation of phenolic hydroxyl groups plays a major role in the dissolution of PHS films in tetramethylammonium hydroxide (TMAH) aqueous developer, it is important to clarify the effects of other interactions. In this study, we investigated the dissolution dynamics of partially protected PHS in organic developer by a quartz crystal microbalance method to deepen the fundamental understanding of the dissolution dynamics of chemically amplified resists. The dissolution dynamics in the solvents, in which the phenolic hydroxyl groups are hardly dissociated, was measured. In a 50 vol% methanol aqueous developer, a large swelling was observed. By decreasing the polarity of the developer, the dissolution dynamics was significantly changed. In the hexyl acetate, the dissolution kinetics of PHS films became similar to that in TMAH aqueous developer although the dissolution mechanism is different.

Exploiting Deep Eutectic Solvent-like Mixtures for Fractionation Biomass, and the Mechanism Removal of Lignin: A Review

Green solvents, which include deep eutectic solvent-like mixtures (DES-like mixtures), are categorized as ecological and economical solvents for the pretreatment and fractionation of different types of biomasses. DES-like mixtures represent a group of the most promising green solvents for lignocellulosic pretreatment and are currently used effectively in the biomass pretreatment process. The present work describes the latest applications of DES-like mixtures in biomass delignification processes and, at the same time, summarizes the mechanism of action and influence of DES-like mixture systems on the removal of lignin from different types of biomasses. The results of this review indicate that the physicochemical properties (acidity, hydrogen bond capacity, polarity, viscosity, and water content) of DES-like mixtures have a significant effect on the biomass fractionation process. In addition to the nature of components forming DES-like mixtures, the reaction conditions (temperature, time) influence the efficiency of delignification. Active protons obtained from the hydrogen bond donor facilitate proton-catalyzed bond cleavage during fractionation, where the most significant step is the destruction of the ether and ester bonds between polysaccharides and lignin. DES-like mixtures can depolymerize lignin with subsequent breakdown of the β−O−4 bonds.

Comparative analysis of tropomyosin allergenicity in three different species of molluscs: insights into the role of amino acid composition in IgE epitopes.

Limited research has been conducted on the differences in allergenicity among Alectryonella plicatula tropomyosin (ATM), Haliotis discus hannai tropomyosin (HTM), and Mimachlamys nobilis tropomyosin (MTM) in molluscs. Our study aimed to comprehensively analyze and compare their immunoreactivity, sensitization, and allergenicity while simultaneously elucidating the underlying molecular mechanisms involved. We assessed the immune binding activity of TM utilizing 86 sera from allergic patients and evaluated sensitization and allergenicity through two different types of mouse models. The dot-blot and basophil activation test assays revealed strong immunoreactivity for HTM, ATM, and MTM, with HTM exhibiting significantly lower levels compared to ATM. In the BALB/c mouse sensitization model, all TM groups stimulated the production of specific antibodies, elicited IgE-mediated immediate hypersensitivity responses, and caused an imbalance in the IL-4/IFN-γ ratio. Similarly, in the BALB/c mouse model of food allergy, all TM variants induced IgE-mediated type I hypersensitivity responses, leading to the development of food allergies characterized by clinical symptoms and an imbalance in the IL-4/IFN-γ ratio. The stimulation ability of sensitization and the severity of food allergies consistently ranked as ATM > MTM > HTM. Through an in-depth analysis of non-polar amino acid frequency and polar hydrogen bonds, HTM exhibited higher frequencies of non-polar amino acids in its amino acid sequence and IgE epitopes, in comparison with ATM and MTM. Furthermore, HTM demonstrated a lower number of polar hydrogen bonds in IgE epitopes. Overall, HTM exhibited the lowest allergenic potential in both allergic patients and mouse models, likely due to its lower polarity in the amino acid sequence and IgE epitopes.

Sequence-Structure Based Comparison of Structurally Homologous Thermophilic and Mesophilic Polyethylene Terephthalate (PET) Hydrolases

Protein structure has a direct impact on thermostability. Deviations in the primary sequence can affect structural changes, leading to alterations in thermostability properties. However, the molecular basis of protein thermostability is unspecified; thus, elucidation of key factors that role particular protein thermostability is required when engineering proteins to be thermostable. To address this challenge, the amino acid composition, hydrophobicity/hydrophilicity ratio, cysteine bridges, and intrinsic features of two structurally homologous but different thermostability, poly(ethylene terephthalate) hydrolase (PETase) were compared. According to the findings, thermostable and thermolabile PETases have similar folds, compactness, and disulfide bridges. Interestingly, an abundance gap of aromaticity, hydrophobic cluster area, polar amino acid and hydrogen bond network compositions demonstrated dominant trends of variations for both PET hydrolases, indicating a pivotal role of these features in the thermostability of PET hydrolase. Furthermore, increased hydrophobic amino acid frequency in the inner surface of thermostable proteins contributed significantly to thermostability by forming more internal hydrophobic interactions and a less hydrophobic patch. There are no consistent trends in insertions and deletions between both PETases. Taken together, these observations demonstrate that hydrophobicity and hydrogen bond networks are essential factors in thermostability of thermostable PETase.

Anion-Dependent Hydrogen-Bond Polarity Switching in Ethylene-bridged Urea Oligomers.

The reversible coordination of anions to an N,N'-disubstituted 3,5-bis(trifluoromethyl)phenylurea located at a terminus of a linear chain of ethylene-bridged hydrogen-bonded ureas triggers a cascade of conformational changes. A series of hydrogen-bond polarity reversals propagates along the oligomer, leading to a global switch of its hydrogen-bond directionality. The induced polarity switch, transmitted through four reversible urea groups, results in a change in emission and excitation wavelengths of a fluorophore located at the opposite terminus of the oligomer. The molecule thus behaves as a chemical sensor with a relayed remote spectroscopic response to variations in anion concentration. The polarity switch induced by anion concentration constitutes an artificial communication mechanism for conveying information through oligomeric structures.

Spectroscopic and molecular docking study of three kinds of cinnamic acid interaction with pepsin

In this work, under simulated physiological conditions (pH = 2.2, glycine hydrochloric acid buffer solution), the interactions of cinnamic acid (CA), m-hydroxycinnamic acid (m-CA) and p-hydroxycinnamic acid (p-CA) with pepsin were studied by fluorescence spectroscopy, ultraviolet–visible absorption spectroscopy, circular dichroism (CD) spectroscopy, Fourier transform infrared spectroscopy (FTIR), molecular docking and molecular dynamic simulation (MD). The spectrogram results showed that these three kinds of CA had a strong ability to quench the intrinsic fluorescence of pepsin, and the quenching effects were obvious with the increase of concentration of these three kinds of molecules. The quenching mechanism of CA, m-CA and p-CA on the fluorescence of pepsin was static quenching. In addition, a stable complex was formed between three kinds of CA with pepsin. Thermodynamic data and docking information suggested that three kinds of CA combine with pepsin were mainly driven by electrostatic force and hydrogen bond. The binding constant and the number of binding sites were determined. The interaction of CA, m-CA and p-CA with pepsin was spontaneous, and accompanied by non-radiative energy transfer. The results from CD, FTIR, UV–Vis and synchronous fluorescence spectra measurements manifested that the secondary structure of pepsin was changed by the binding of three kinds of CA. The β-sheet of pepsin increased after the interaction with three kinds of CA. The assay results of pepsin activity showed that three kinds of CA led to a decrease in pepsin activity within the investigated concentrations. Molecular docking investigation revealed the formation of polar hydrogen bonds as well as hydrophobic interactions between three kinds of CA with pepsin, and the ligand within the binding pocket of pepsin. MD results implied the formation of a stable complex between three kinds of CA and pepsin. The research suggested that cinnamic acid and its derivatives could be a potential effect on the structure and properties of digestive enzyme.

White light generation by regulating hydrogen bond-sensitive ESPT of naphthalimide dyes

White light emitting systems of pure organic materials have attracted extensive research interest due to their better compatibility and functional scalability. The reported organic white light materials are mainly based on the multi-channel emission regulation of the compound itself or the mixing of multicolor luminescence materials, but studies on the dependence between multicolor luminescence and the external environment are lacking, which limits the application of these materials in areas such as identification and sensing. This paper reports that the 4- or 3‑hydroxyl-substituted naphthalimides NapH1 and NapH2 form intermolecular hydrogen bonds with adjacent molecules in the environment, and undergo excited-state intermolecular proton transfer under irradiation, resulting in blue-yellow or blue-red dual fluorescence emission, respectively. Since the two compounds have different two-color luminescence channels and the two-color intensity ratio is affected by the environment, and the intermolecular hydrogen bond is determined by the hydrogen bond receptor, polarity, and temperature in the environment, the full spectrum from blue to red light and white light emission can be obtained by adjusting the mixing ratio of the two dyes and the solvent polarity and the ambient temperature. This environmentally sensitive white emission is used to detect the alkalinity of different papers, and the dyed paper can be used as a test strip for acid-base vapor detection.

Measuring Nintedanib esylate solubility in binary mixed solvents: Molecular dynamic simulation, solid-liquid phase equilibrium and thermodynamic analysis

By laser monitoring method, the solid–liquid phase equilibrium solubility of Nintedanib esylate in the four binary mixtures (including methanol (MeOH) + ethyl acetate (EtOAC), N,N-Dimethylformamide(DMF) + ethyl acetate (EtOAC), N,N-Dimethylacetamide (DMAC) + ethyl acetate (EtOAC), and methanol (MeOH) + methyl tert-butyl ether(MTBE)) was achieved at different temperatures and atmospheric pressure. The result demonstrated that the solubility in the four binary mixed solvents was positively correlated with temperature and the mass fractions of DMAC, DMF and MeOH at a certain temperature. Correlation fitting was performed for the solubility data through Apleblat model, Ma model, λh model, CNIBS/R-K model and NRTL model, and the result showed that the CNIBS/R-K model had much lower relative average deviations than the others for the four solvents being researched. By using RDF and MD simulation, the intermolecular interactions of Nintedanib esylate and the chosen solvents proved that the ranks of the interactions between solute and solvent, as well as solvent and solvent, were bound up with the order of the saturation solubility of Nintedanib esylate in the chosen solvents. The calculation of Hansen solubility parameters of the solute molecules showed that the Hansen solubility parameters could explain the solubility of the solute in the four binary solvents and the solubility of the solute in the four binary solvents was affected by various factors such as dispersion force, hydrogen bond force and polarity force between molecules. The NRTL model and Van't Hoff equation were used to calculate the thermodynamic properties of the solute mixing process and the apparent thermodynamics of the solute dissolution process in the mixed solvent. The results show that: The mixing process of Nintedanib esylate in the selected four mixed solvents is spontaneous and entropy increasing process, and the dissolution process is enthalpy driven, endothermic and non-spontaneous process.

Structural, thermal and dielectric properties of glycerolized hydrogen‐bonded polyvinyl alcohol films

AbstractIn order to evaluate the influence of plasticizers on the behavior of the dielectric properties of polymers intended for the elaboration of flexible sensors, we have studied the influence of the addition of glycerol (10 wt%–40 wt%) in polyvinyl alcohol (PVA). Once processed, the PVA films were not subjected to any particular annealing and they were dried at room temperature for 24 h before being characterized. This choice allows both to take advantage of the presence of water in the bulk of the material, which will help to make the PVA more flexible (increase of plasticization effect produced by extra‐H‐bonding) and avoid a transient behavior of water absorption into the material, as we could verify. DSC and FTIR investigations confirm good intermolecular interaction between vinyl polymer chains, glycerol, and water molecules. Dielectric spectroscopy analysis, carried out in [25°C–110°C] temperature and [0.1 Hz–1 MHz] frequency ranges, reveals a significant increase in the dielectric constant when the glycerol content is higher (at 0.1 Hz: 322 for pure PVA, 1.3 × 106 with 40 wt% of glycerol). Polar hydrogen bonds introduced by the glycerol are the main reason for this increase. Ionic conductivity induced by these dipoles dominates the loss tangent response of the material. The activation energy obtained from the DC conductivity plateau obeys to a conventional Arrhenius law with a decreasing value at highest glycerol contents (1.35 eV for pure PVA against 0.46 eV with 40 wt% of glycerol).

Relating Crystal Structure to Surface Properties: A Study on Quercetin Solid Forms.

The surface energy and surface chemistry of a crystal are of great importance when designing particles for a specific application, as these will impact both downstream manufacturing processes as well as final product quality. In this work, the surface properties of two different quercetin solvates (quercetin dihydrate and quercetin DMSO solvate) were studied using molecular (synthonic) modeling and experimental techniques, including inverse gas chromatography (IGC) and contact angle measurements, to establish a relationship between crystal structure and surface properties. The attachment energy model was used to predict morphologies and calculate surface properties through the study of their growth synthons. The modeling results confirmed the surface chemistry anisotropy for the two forms. For quercetin dihydrate, the {010} facets were found to grow mainly by nonpolar offset quercetin–quercetin stacking interactions, thus being hydrophobic, while the {100} facets were expected to be hydrophilic, growing by a polar quercetin–water hydrogen bond. For QDMSO, the dominant facet {002} grows by a strong polar quercetin–quercetin hydrogen bonding interaction, while the second most dominant facet {011} grows by nonpolar π–π stacking interactions. Water contact angle measurements and IGC confirmed a greater overall surface hydrophilicity for QDMSO compared to QDH and demonstrated surface energy heterogeneity for both structures. This work shows how synthonic modeling can help in the prediction of the surface nature of crystalline particles and guide the choice of parameters that will determine the optimal crystal form and final morphology for targeted surface properties, for example, the choice of crystallization conditions, choice of solvent, or presence of additives or impurities, which can direct the crystallization of a specific crystal form or crystal shape.

Spectroscopic, electronic structure, molecular docking, and molecular dynamics simulation study of 7-Trifluoromethyl-1H-indole-2-carboxylic acid as an aromatase inhibitor

The present work encompasses a combined experimental and theoretical investigation of the molecular structure, vibrational wavenumbers, electronic structure at the ground and electronic excited states, molecular electrostatic potential surface of 7-(Trifluoromethyl)-1H-indole-2-carboxylic acid (TICA) and possibility of the title molecule as an aromatase inhibitor using molecular docking and molecular dynamic simulations. A stable conformer has been obtained using potential energy scans by varying appropriate dihedral angles. The obtained minimum energy conformer was further optimized at the 6–311++G (d, p) basis set by applying the most accepted B3LYP functional. A good agreement between experimental and calculated normal modes of vibration has been observed. The hydrogen-bonded interaction between two monomeric units of TICA has been investigated using NBO,QTAIM, and NCI (noncovalent interactions) analysis. Molecular docking of TICA with human placental aromatase (PDB ID: 3S79) reveals the formation of polar hydrogen bonds as well as hydrophobic interactions between the ligand and the protein, right in the binding cavity. TICA satisfies all pharmacokinetic filters (Lipinski rule of five, the Veber rule, Ghose rule, Egan rule, as well as the Muegge rule) and has a high bioavailability score of 0.85. Dynamic stability of the ligand within the binding pocket of the target protein has been confirmed by 100 ns molecular dynamics simulation results. The present study provides an excellent starting point for additional in vivo research, and TICA may eventually serve as a significant therapeutic candidate for the treatment of breast cancer.

Reversible Capture and Release of a Ligand Mediated by a Long-Range Relayed Polarity Switch in a Urea Oligomer.

Ethylene-bridged oligoureas characterized by a continuous, switchable chain of hydrogen bonds and carrying a binding site (an N,N′-disubstituted urea) for a hydrogen-bond-accepting ligand (a phosphine oxide) were synthesized. These oligomers show stronger ligand binding when the binding site is located at the hydrogen-bond-donating terminus than when the same binding site is at the hydrogen-bond-accepting terminus. An acidic group at the terminus remote from the binding site allows hydrogen bond polarity, and hence ligand binding ability, to be controlled remotely by a deprotonation/reprotonation cycle. Addition of base induces a remote conformational change that is relayed through up to five urea linkages, reducing the ability of the binding site to retain an intermolecular association to its ligand, which is consequently released into solution. Reprotonation returns the polarity of the oligomer to its original directionality, restoring the function of the remote binding site, which consequently recaptures the ligand. This is the first example of a synthetic molecular structure that relays intermolecular binding information, and these “dynamic foldamer” structures are prototypes of components for chemical systems capable of controlling chemical function from a distance.

Impact of Ultrafast Electric Field Changes on Photoreceptor Protein Dynamics.

Studies on photoreceptors provide a wealth of information on cofactor and protein dynamics on the microsecond to seconds time-scale. Up to now, ultrafast dynamics addresses mainly the cofactor or chromophore, but ultrafast protein dynamics are poorly understood. Increasing evidence show that protein responses can occur even faster than the cofactor dynamics. The causal reason for the ultrafast protein response cannot be explained by the localized cofactor excitation or its excited-state decay, alone. We propose a Coulomb interaction mechanism started by a shock wave and stabilized by a dipole moment change at least partially responsible for coherent oscillations in proteins, protonation changes, water dislocations, and protein changes prior to and beyond chromophore's excited-state decay. Photoexcitation changes the electron density distribution of the chromophore within a few femtoseconds: The Coulomb shock wave affects polar groups, hydrogen bonds, and protein bound water molecules. The process occurs on a time-scale even faster than excited-state decay of the chromophore. We discuss studies on selected photoreceptors in light of this mechanism and its impact on a detailed understanding of protein dynamics.

BaTiO3/Polyurethane Dielectric Composites with Diels-Alder Bond for Improved Self-Healing Properties

In general, self-healing dielectric composites are mainly composed of polar hydrogen bonds, which have high hydrophilicity and are unsuitable for humid environment. Dielectric composite with Diels-Alder (D-A) bond contains covalent bonds, it can be adopted as an efficient self-healing material. Here, we construct self-healing barium titanate (BT)/polyurethane (PU) dielectric composites by adopting PU with D-A bond as matrix (BT/ PU-DA). The prepared 10% BT/PU-DA composite exhibits superior self-healing ability than that of PU-DA. Moreover, its dielectric constant can reach 9.3 with a loss of only 0.04 at 1000 Hz and maintain 93% repair effi- ciency of tensile strength. The experimental analysis suggests the introduction of D-A bond can enhance the thermostability and self-healing ability of BT/PU-DA composite. In addition, the incorporation of BT nanoparticles and D-A bond in the self-healing composite contributes to the lower dielectric loss and excellent tensile strength after healing. The adopted strategy is a promising and facile approach to develop highly efficient self-healing dielectric material, which will be conducive to reuse and sustainable development of the electronic packaging material in aqueous medium or wet environment.

Facile anchoring mussel adhesive mimic tentacles on biodegradable polymer cargo carriers via self-assembly for microplastic-free cosmetics

Enhancing the deposition of fragrance delivery systems contained in personal care products on target surfaces is crucial for increasing the longevity of scent, efficiently utilizing expensive functional compounds and limiting the generation of microplastics in domestic waste water. In this work, we designed and synthesized a new type of biomimetic macromolecules, chitosan-graft-L-lysine-L-DOPA (C-L-D), as a versatile biodegradable adhesion promoter to facilitate the deposition of biodegradable fragrance carriers on diverse surfaces including hair, cotton and skin. The C-L-D has hyperbranched chain architecture with many oligopeptide adhesive tentacles, each being a simple mimic of mussel adhesive proteins. It also exhibits unique amphiphilic characteristic. As a result, it could be facilely anchored on cargo-loaded poly(lactic-co-glycolic acid) nanoparticle surface via self-assembly in the particle preparation process. The C-L-D-modified nanoparticles show significantly higher deposition efficiencies than polyvinyl alcohol- and chitosan-coated particles when deposited on the target surfaces in different aqueous media as the lysine and DOPA units are capable of providing multi-noncovalent interactions, including electrostatic, polar, hydrophobic interactions, and bidentate hydrogen bonds, with the target surfaces, and possibly also inducing oxidative cross-linking. A much higher retention rate of the C-L-D-modified nanoparticles on cotton surface is also observed after washing with a soap solution, which could be attributed to the significant role played by bidentate hydrogen bonds. These findings suggest that C-L-D is a versatile biodegradable adhesion promoter and has the potential to be applied for various personal care applications and beyond.

Fabricating self‐stratifying coating for superhydrophobic cotton textile

AbstractIn this paper, a type of superhydrophobic cotton textile was designed and prepared. Particularly, it was obtained by coating a type of acrylic‐silicone hybrid resin onto the cotton fabric. With self‐stratifying character, the cured coating can be formed into two layers, in which the acrylic component in the bottom layer enables polar bond or hydrogen bond linkage with cellulose molecules on the fiber surface, while the amino silicone oil resin on the surface layer acts as a functional part and adds new surface features to the cotton fabric. As a result, the coated cotton fabric displayed superhydrophobicity, with a water contact angle above 150° and a rolling angle less than 8°. The experimental findings indicated that the fabricated textile had adequate mechanical strength to withstand sandpaper abrasion for 20‐cycles abrasion by pressing a constant load of 500 g. Additionally, the modified textiles exhibited stable oil–water separation abilities, therefore showing multifunctional properties that have potential applications in many cotton textile surface treatments.

Prediction of degradability of micropollutants by sonolysis in water with QSPR - a case study on phenol derivates

The increasing quantity and variety of organic contaminants discharged into surface and groundwater increase the necessity of additional and suitable water treatment methods, which can be incorporated into existing wastewater treatment plants. The huge variety of micropollutants and local variability of the composition of the organic load or matrix effects paired with multiple possible degradation processes lead to the requirement of a recommendation tool for the best possible water treatment method under given local conditions. Due to the diversity of physicochemical properties of micropollutants, such predictions are challenging. In this study, a quantitative correlation between the structural properties of certain micropollutants and their degradability using high-frequency sonolysis has been investigated. Therefore, Quantitative Structure-Property Relationship (QSPR) has been applied on a set of phenol derivates. To obtain the kinetic data, all experiments have been conducted in standardized, constant conditions for all 32 investigated phenol derivates. QSPR modelling was then executed using the software PaDEL for descriptor calculation and the software QSARINS for the overall modelling process including genetic algorithm (GA) and multiple linear regression (MLR). The final model consisting of 5 molecular descriptors was selected using a multi-criteria decision-making method based on extensive statistical parameters. The predictive power and robustness of the model was evaluated by means of internal cross validation and external validation using an independent validation set. The final selected model showed very good values for regression abilities, predictive power as well as stability (R2adj = 0.9455, CCCtr = 0.9777, Q2loo = 0.9285, CCCext = 0.9797 and Q2ext-F1 = 0.9711). The applicability domain of the QSPR model was defined based on the Williams plot and Insubria plot. The five OECD principles for the application of QSPR/QSAR modelling in industry and regulation were fulfilled in the whole process to the best of our knowledge, including the collection of the underlying experimental data as well as the entire modelling process. The final QSPR model included the molecular polarity and occurrence of hydrogen bonds as major influences on the reaction rate constants in accordance with previous studies. Nevertheless, potential biases in the selection of these descriptors due to the small size of the dataset were highlighted.

Epigallocatechin-3-Gallate Allosterically Activates Protein Kinase C-α and Improves the Cognition of Estrogen Deficiency Mice.

Protein kinase C (PKC) isozymes play essential roles in biological processes, and activation of PKC is proposed to alleviate the symptoms of a variety of diseases. It would be of great significance to find effective pharmacological modulators of PKC isozymes that can be translated for clinical use. Here, using in vitro activity assay, we demonstrated that green tea extract (-)-epigallocatechin-3-gallate (EGCG) dose-dependently activated PKCα with a half effective concentration (EC50) of 0.49 μM. We also performed surface plasmon resonance analysis and found that EGCG binds PKCα with an equilibrium dissociation constant (KD) value of 4.11 × 10-6 mol/L. Further computational flexible docking analysis revealed that EGCG interacted with the catalytic C3-C4 domain of PKCα (PDB: 4RA4) through establishing polar hydrogen bonds with V420, T401, E387, and K368 of PKCα, and the benzene ring group of EGCG hydrophobically interacted with the hydrophobic pocket formed by L345, M470, I479, and V353 of PKCα. Interestingly, the PKCα-selective blocker Ro-32-0432 could compete with EGCG for the same substrate-binding pocket of PKCα. Moreover, we found that EGCG dose-dependently improved the spatial memory, object recognition ability, and hippocampal long-term potentiation of ovariectomized mice, which was offset by Ro-32-0432. Collectively, our findings reveal a novel PKCα agonist and open the way to a new perspective on PKCα pharmacology and the treatment of PKCα-related diseases, including cognitive impairment.