Molecular Structure Properties Research Articles

Wormlike Micellar Glycerol Solutions Formed from a Double-Tailed Surfactant with Two Quaternary Ammonium Head Groups.

Herein, a quaternary ammonium surfactant with dual heads and tails, N1,N1,N1,N3,N3-pentamethyl-N3-(3-(2-tetradecylhexadecanamido)propyl)propane-1,3-diaminium dibromide, abbreviated as Di-C14-N2, was synthesized. For the first time, clear observation of aggregate structures formed by surfactants in pure glycerol systems was achieved using cryogenic transmission electron microscopy (cryo-TEM). The system's rheological properties were analyzed using both steady-state shear and oscillatory rheological measurements. The lubricating efficiency of the Di-C14-N2 glycerol solution was assessed for its tribological properties using a tribological wear tester, white light interferometer, and scanning electron microscope. In glycerol, Di-C14-N2 formed long wormlike micelles, which resulted in a glycerol solution with the zero-shear viscosity of 1013 Pa·s at 90 mM, which is the most viscous glycerol system up to now. The system displayed distinct rheological properties from the aqueous system, as evidenced by two intersections in the loss and storage moduli. The formed wormlike micelles in glycerol lead to a significant alteration in the viscoelasticity of the system, thus endowing the Di-C14-N2 glycerol solution with potential as an eco-friendly lubricant. The friction coefficient of the system was found to be 23% lower and the wear rate was 83% lower than that of pure glycerol after the addition of Di-C14-N2. This demonstrates that the addition of Di-C14-N2 greatly improves the frictional properties of pure glycerol. This study offers the possibility of directly observing the aggregate structures formed by surfactants in pure glycerol systems. It contributes to the exploration of the self-assembly behavior of surfactants in nonaqueous polar media, thereby aiding in a deeper understanding of the correlation between molecular structure, mesoscale structure, and macroscopic properties.

Ionomeric Binders for High Temperature Proton Exchange Membrane Fuel Cells.

High-temperature proton exchange membrane fuel cell (HT-PEMFC) based on phosphoric acid doped polybenzimidazole membrane (PBI/PA) operating at 120-200 °C can provide insensitivity to carbon monoxide (CO) and simplified managements of water and heat and thus attract significant global attention. However, one significant drawback is its low utilization of precious metal catalysts resulted from the PA poisoning and inefficient three-phase boundary. Studies of binder materials in catalyst layers for HT-PEMFC are gradually emerging and there are few literature reviews on this important topic. The purpose of this review is to describe the various types of binders based on their molecular structure and electrochemical properties, with particular emphasis on catalyst layer for fuel cells. Importantly, this review provides a better understanding of relationship between fuel cell performance and the gas permeability and conductivity of different binders. Then, future directions of research and development in binder materials of HT-PEMFC are pointed out.

Sensing the structural and conformational properties of single-stranded nucleic acids using electrometry and molecular simulations

Inferring the 3D structure and conformation of disordered biomolecules, e.g., single stranded nucleic acids (ssNAs), remains challenging due to their conformational heterogeneity in solution. Here, we use escape-time electrometry (ETe) to measure with sub elementary-charge precision the effective electrical charge in solution of short to medium chain length ssNAs in the range of 5–60 bases. We compare measurements of molecular effective charge with theoretically calculated values for simulated molecular conformations obtained from Molecular Dynamics simulations using a variety of forcefield descriptions. We demonstrate that the measured effective charge captures subtle differences in molecular structure in various nucleic acid homopolymers of identical length, and also that the experimental measurements can find agreement with computed values derived from coarse-grained molecular structure descriptions such as oxDNA, as well next generation ssNA force fields. We further show that comparing the measured effective charge with calculations for a rigid, charged rod—the simplest model of a nucleic acid—yields estimates of molecular structural dimensions such as linear charge spacings that capture molecular structural trends observed using high resolution structural analysis methods such as X-ray scattering. By sensitively probing the effective charge of a molecule, electrometry provides a powerful dimension supporting inferences of molecular structural and conformational properties, as well as the validation of biomolecular structural models. The overall approach holds promise for a high throughput, microscopy-based biomolecular analytical approach offering rapid screening and inference of molecular 3D conformation, and operating at the single molecule level in solution.

Effects of glycation modifications of different glycosylating agents on the molecular structure and gel properties of sheep's hoof gelatin

In this study, we utilized sheep's hoof gelatin as a raw material to modify gelatin by non-enzymatic glycation reactions using five different monosaccharides (D-glucose, D-sorbose, D-fructose, D-ribose, and D-erythrose) and five different polysaccharides (pectin, inulin, carrageenan, xanthan gum, and konjac glucomannan) and comparatively analyzed the properties (rheological properties, textural properties, and thermal stability) of differently glycosylated sheep's hoof gelatin to determine the mechanism of different glycosylating agents on the molecular properties and gel performance of sheep's hoof gelatin. The results showed that the reactivity (DG value) and phase transition temperature (Td value) of gelatin modified with monosaccharide glycosylates were notably higher (p < 0.05) compared to those modified with polysaccharides, resulting in a micro-network structure with finer pore size. Conversely, polysaccharide glycosylation significantly enhanced the mechanical properties and rheological characteristics of gelatin (p < 0.05). The formation of a mosaic network structure in the polysaccharide-glycosylated gelatin group played a pivotal role in enhancing gel properties. Notably, the gel strength (584.62 ± 6.34 g), viscosity (η-value), and gel melting temperature (37.85 ± 0.20°C) of the polysaccharide S-PEC were significantly higher than the other treatment groups (p < 0.05). This research not only provides a new perspective for modifying gelatin derived from sheep's hooves but also offers an important theoretical basis for the exploration and application of gelatin materials in the food industry.

Aqueous ozone effects on wheat gluten: Yield, structure, and rheology.

This study investigates the impact of aqueous ozone (AO) on the yield, molecular structure, and rheological properties of wheat gluten separated using the batter procedure. Employing strong gluten flour (SGF) and weak gluten flour (WGF), we demonstrate that AO pretreatment significantly enhances the yield and purity of separated starch and gluten. Surface hydrophobicity, free sulfhydryl groups, Fourier transform infrared spectroscopy (FTIR), Raman, and size exclusion-high-performance liquid chromatography (SE-HPLC) analyses were used to evaluate the effects of AO on the molecular structure of gluten. Our analysis reveals that low concentrations of AO induce specific modifications in gluten proteins. AO treatment increases cross-linking in glutenin macropolymer (GMP), reduces surface hydrophobicity, and stabilizes secondary and tertiary structures. These changes include an increase in β-sheet content by approximately 9% and a corresponding decrease in β-turn structures, leading to enhanced viscoelastic properties of the gluten. The research highlights AO's potential as a sustainable and efficient agent in wheat flour processing, offering advancements in both product quality and eco-friendly processing techniques. Future research should optimize AO treatment parameters and explore its effects on different cereal types further to enhance its applicability and benefits in food processing. PRACTICAL APPLICATION: Our work substantially advances the existing knowledge on wheat flour processing by demonstrating the multifaceted benefits of AO pretreatment. We unveil significant improvements in the yield and purity of starch and gluten when compared to conventional separation methods. Moreover, our in-depth analysis of molecular changes induced by AO, including increased cross-linking, alterations in surface hydrophobicity, and modifications in glutenin macropolymer content, provides new insights into how AO affects the viscoelastic properties of gluten. This contribution is pivotal for the development of more efficient, sustainable, and eco-friendly wheat flour processing technologies.

Impact of waxy protein deletions on the crystalline structure and physicochemical properties of wheat V-type resistant starch (RS5)

This study investigated the effects of waxy (Wx) protein on wheat V-type resistant starch (RS5) formation, molecular structure, and physicochemical properties. We discovered that waxy protein deletions led to a rise in B- and C-type starch granules, while reducing A-type starch granules, amylose, and slowly digestible starch contents. Further, dodecyl gallate (DG) addition significantly increased RS5 content, and molecular dynamics simulations indicated that amylose and DG can form stable complexes. Molecular docking indicated that DG could potentially aid in protecting wheat starch from digestion by human α-glucosidase. RS5 content was significantly reduced by waxy protein deletions. X-ray powder diffraction, Fourier-transform infrared spectroscopy, and laser confocal microscopy-Raman analyses revealed that waxy protein deletions decreased long-range crystalline structures and relative crystallinity and increased short-range crystalline structures，and full width at half maximum at 480 cm−1 of RS5. Pearson correlation analysis showed that RS5 content was highly correlated with its crystal structure, functional characteristics, and digestive characteristics. Principal component analysis revealed that five parameters (amylopectin, long-range crystalline structures, amylose, relative crystallinity, and RS5 content) had significant effect on the crystalline structure and functionality of RS5.

Ab initio study of the interaction between the charged system (FH+) and the He atom

We investigated the molecular structure and spectroscopic properties of the charged system (FH+) in interaction with a helium atom using an ab initio quantum chemistry approach in Jacobi coordinates. Our study focused on the ground state X2Π of (FH+) with various theoretical methods including UCCSD, UCCSD(T) and UCCSD(T)-F12, alongside basis sets like aug-cc-pVnZ (n = T, Q, 5, and 6) and cc-pVQZ-F12. We evaluated how these methods and basis sets affect the minimum energies We assessed the impact of the methods, basis sets, and extrapolation approaches on the minimum energies. Potential energy surfaces (PES) were generated using the correlated UCCSD(T)-F12 method with cc-pVQZ-F12 for hydrogen and fluorine, and cc-pVQZ-F12/optri for helium. These surfaces, considering spin-orbit coupling, are degenerate for linear geometries (θ=0° and θ=180°) of the (FH+)-He complex and correlate with the doubly degenerate X2Π state of (FH+). Our results reveal a strong anisotropic character at short and intermediate distances and a quasi-isotropic character upon dissociation into FH+ and He. We compared the spectroscopic parameters of the (FH+)-He complex with existing theoretical data, finding that the linear arrangement exhibits the highest stability, consistent with previous results for similar complexes. This conclusion is supported by the Milliken atomic charge distribution and a three-dimensional map of the Molecular Electrostatic Potential. Additionally, we used the LEVEL program, to calculate the bound rovibronic levels of the (FH+)-He complex for angular momentum values Ω=1/2 and Ω=3/2. Utilizing our ab initio results and a general interpolation approach based on the Reproducing Kernel Hilbert Space method, we generated contour maps illustrating the analytical potential for the (FH+)-He system. These findings will be employed to study the stabilities, geometries, energetics, and structures of the FH+ charged system within helium clusters.

On physical analysis of topological indices for iron disulfide network via curve fitting model

In this study, we conduct a comprehensive physical analysis of topological indices for the Iron Disulfide (FeS2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document}) network using a curve-fitting model. Iron Disulfide is a cubic compound. In metamorphic rock, sedimentary rock, and quartz veins, it is typically found in combination with other sulfides or oxides. The numerical properties of molecular structures are referred to as topological indices. There are several different kinds of topological indices, including those that are based on distance, degree, or counting, among other factors. The real process of creating a topological index involves turning a chemical structure into a numerical value. In this paper, we calculate the iron disulfide network topological indices using the degrees of vertices in a chemical network of Iron Disulfide (FeS2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document}). Thereafter, we discovered the physical parameters of FeS2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document} production, such as heat of formation. We then fitted curves between the thermodynamic properties and several indices. Several techniques based on rationality, linearity, and nonlinearity were used to fit curves in MATLAB. These quantitative results imply that a variety of thermodynamic characteristics of semiconducting materials may be accurately predicted by topological indices. These findings have significant ramifications as they provide the groundwork for the application of topological indices in semiconducting network design and optimization, which might result in more effective and economical material creation.

Impact of freeze-thaw cycles on the physicochemical properties and structure-function relationship of potato starch with varying granule sizes in frozen dough

Starch, as a critical component of dough, significantly influences quality preservation during the freezing process. In particular, the fine structure of potato (B-type) starch in frozen processing is a subject of considerable interest. This study aims to investigate the intrinsic differences of B-type starch and the impact of freeze-thaw (F/T) treatment on its molecular structure and physicochemical properties. Chain length distribution and X-ray photoelectron spectroscopy were utilized to examine the structural characteristics of natural potato starch with different granule sizes. Furthermore, the fine structure, thermal properties, and rheological properties of the isolated starches after F/T treatment were analyzed. The results indicate that potato starch with smaller particle sizes exhibits higher surface CC and PO content along with a higher proportion of very short chains (DP < 6, 8.17 %) and long B chains (DP > 25, 20.68 %). The study found that after F/T treatment, the surface of small-sized starch granules was initially damaged, exhibiting threads on the surface centered on the umbilical point. Following F/T treatment, both the crystallinity (very large (VL): 24.52–18.36 %; small (S): 17.03–16.69 %) and short-range order (VL: 2.97–2.61; S: 2.71–2.35) of starch particle size decreased. Both the amylose content (20.88–14.57 %) and ΔH (10.15–8.62 J/g) of isolated starch after freeze-thaw-treated dough exhibited a decrease to varying degrees. With the exception of the fifth cycle, small-size starch particles exhibited relatively higher G' and G" values and showed significant changes as a result of F/T treatment, demonstrating high hardness and complex viscosity. Clarifying the physicochemical properties of potato starches with different granule sizes is expected to expand their applications in frozen dough.

Modulation of Mechanical Properties of Silica-Filled Silicone Rubber by Cross-Linked Network Structure.

Associating molecular structure and mechanical properties is important for silicone rubber design. Although silicone rubbers are widely used due to their odourless, non-toxic, and high- and low-temperature resistance advantages, their application and development are still limited by their poor mechanical properties. The mechanical properties of silicone rubbers can be regulated by designing the cross-link density and cross-linking structure, and altering the molar contents of vinyl in the side groups of methyl vinyl silicone rubber (MVQ) leads to different cross-linking structures and cross-linking densities in the vulcanized rubber. Therefore, this study investigated the differences in molecular parameters and molecular chain structures of unprocessed MVQ rubbers with different vinyl contents. The results showed that MVQ rubbers with high vinyl contents were branched polymers, better facilitating the cross-linking reaction than MVQ rubbers with low vinyl contents. In addition, silicone rubbers with different vinyl contents were co-cross-linked to introduce an inhomogeneous cross-linked network in the silicone rubber to improve its mechanical properties. The cross-linked network properties were analysed by the Flory-Rehner model and Mooney-Rivlin plots, and it was found that the long chains in the sparsely cross-linked domains of the network favoured high elongation at break and the short chains in the densely cross-linked domains contributed to high modulus, which could satisfy the functions of reinforcing and toughening the rubber materials at the same time. It was also found by analysing the filler network and aggregate morphology that the inhomogeneous cross-linked network led to an improvement in the dispersion of silica in the rubber and a significant improvement in the mechanical properties of silicone rubber.

Microwave Synthesis of New Co-Polypyrrole-Polyketone Anion Exchange Membranes

Polyketones can be easily converted in a series of new polymeric anion exchange membranes (AEMs) with a stable polypyrrole-polyketone backbone structure from which the ion exchange side-groups stem [1-3]. Here we present our findings on the functionalization with two different cycloaliphatic primary amines of a commercial and inexpensive terpolymer polyketone (PK) through the Paal-Knorr chemistry. We also studied the possibility to drastically reduce the reaction time by investigating alternative and greener heating sources such as microwave heating. The molecular structure, thermal and conductive properties of the membranes were studied in order to shed light on and compare the effect of the different heating methods on the materials behavior [4], and to lead the way to their further optimization for the possible application in electrochemical devices. The obtained membranes showed a promising anion conductivity in the hydroxide form, up to 10mScm-1, and an exceptional thermal stability, about 250°C.[1] G.Nawn, K.Vezzù, G.Cavinato, G.Pace, F.Bertasi, G.Pagot, E.Negro, V. Di Noto, Adv. Funct. Mater. 2018, 1706522[2] N.Ataollahi, F.Girardi, E.Cappelletto, K.Vezzù, V.Di Noto, P.Scardi, E.Callone, R.Di Maggio. Journal of Applied Polymer Science. 2017, 134, 45485.[3] A.R.Alvi, K.Vezzù, , G.Pagot, P.Sgarbossa, G.Pace, V.Di Noto, Macromolecular Chemistry & Physics. 2022, 223, 2100409.[4] S.Bonizzoni, D.Stucchi, T.Caielli, E.Sediva, M.Mauri, P.Mustarelli, ChemElectroChem. 2023, e202201077. Figure 1

Curing kinetics and mechanical properties of the epoxy vitrimer based on transesterification and its composite laminates

AbstractThe resin is a fundamental factor in determining the performance and usage conditions of its composites. The epoxy vitrimer, which combines both thermoplastic and thermosetting properties, shows significant potential in extending the service life of material. The curing process significantly affects the macroscopic properties of the vitrimer and the resulting carbon fiber reinforced plastics (CFRP). Effective control of curing parameters constitutes the critical factor for the assurance of product quality. In the study, a differential scanning calorimetry (DSC) was utilized to establish a curing kinetics model for a modified, self‐healable epoxy vitrimer based on transesterification. Then the molecular structure, thermodynamic, and mechanical properties of the cured vitrimer were analyzed. Next vitrimeric CFRP (vCFRP) laminates were fabricated, and the tensile and bending properties of the vCFRP laminates were investigated. The results showed the curing process was obtained: 95°C/1 h + 150°C/2 h + 170°C/2 h. The thermodynamic and mechanical properties of cured vitrimer could meet practical requirements. The minimal differences observed in the stress–strain curves of the specimens indicated that the curing process was appropriately configured. The prepared laminates exhibited performance comparable to that of commercial thermosetting composites.

Density functional theory and spectroscopic analysis of stigmasterol from Garcinia wightii: Deciphering its inhibitory potential against drug-resistant tuberculosis via insilico molecular docking and molecular dynamics simulations

This study investigates the molecular structure and electronic properties of stigmasterol, isolated from Garcinia wightii, using density functional theory (DFT) alongside experimental techniques including FT-IR, FT-Raman, UV–Vis, 1H and 13C NMR spectroscopy. Theoretical predictions are compared with experimental results, facilitated by vibrational energy distribution analysis for unambiguous vibrational wavenumber assignments. Natural bond orbitalanalyzes reveal donor-acceptor bond energies and electron densities, while Fukui functions identify reactive sites susceptible to electrophilic and nucleophilic attacks. Electronic properties are further explored through various analyzes, unveiling reactive surface sites. Non-covalent interactions are examined using reduced density gradient analysis. Assessment of absorption, distribution, metabolism, and excretion attributes aids in drug discovery efforts. Molecular docking studies against 20 target proteins for antitubercular screening show a stable glide score of -9.52 kcal/mol for the protein 4FDO (Mycobacterium tuberculosis DprE1 in complex with CT319). Molecular dynamics simulations over 100 ns indicate the stability of the ligand-protein complex, suggesting its potential as an antituberculosis agent. Stigmasterol's structural, vibrational, electronic, and topological properties are thoroughly investigated, revealing its ring skeleton with a flexible isooctyl side chain, adhering to C1 point group symmetry. Steric and stereo electronic interactions play crucial roles in conformation and binding to target proteins. Theoretical and experimental analyzes align, confirming the compound's bioactive properties. This comprehensive investigation underscores stigmasterol's potential as a tuberculosis treatment option, providing valuable insights into its structural characteristics and therapeutic possibilities.

Physicochemical, structural and functional properties of pomelo peel pectin extracted by combination of pulsed electric field and cellulase hydrolysis

In this study, pectin extracted from pomelo peel was investigated using three different combination methods of pulsed electric field (PEF) and cellulase. Three action sequences were performed, including PEF treatment followed by enzymatic hydrolysis, enzymatic hydrolysis followed by PEF treatment, and enzymatic hydrolysis simultaneously treated by PEF. The three corresponding pectins were namely PEP, EPP and SP. The physiochemical, molecular structural and functional properties of the three pectins were determined. The results showed that PEP had excellent physiochemical properties, with the highest yield (12.08 %), total sugar (80.17 %) and total phenol content (38.20 %). The monosaccharide composition and FT-IR analysis indicated that the three pectins were similar. The molecular weights of PEP, EPP and SP were 51.13, 88.51 and 40.00 kDa, respectively. PEP showed the best gel properties, emulsification stability and antioxidant capacity among the three products, due to its high galacturonic acid and total phenol content, appropriate protein and low molecular weight. The mechanism of PEF-assisted cellulase hydrolysis of pomelo peel was also revealed by SEM analysis. These results suggested that PEF pretreatment was the best method, which not only improved the efficiency of enzymatic extraction, but also reduced resource waste and increased financial benefits.

Design Strategy for the Synthesis of Self-Doped n-Type Molecules.

n-Type organic conductive molecules play a significant role in organic electronics. Self-doping can increase the carrier concentration within the materials to improve the conductivity without the need for additional intentional dopants. This review focuses on the various strategies employed in the synthesis of self-doped n-type molecules, and provides an overview of the doping mechanisms. By elucidating these mechanisms, the review aims to establish the relationship between molecular structure and electronic properties. Furthermore, the review outlines the current applications of self-doped n-type molecules in the field of organic electronics, highlighting their performance and potential in various devices. It also offers insights into the future development of self-doped materials.

Tailoring molecular structure and electromechanical properties of polydimethylsiloxane elastomer for enhanced energy conversion efficiency

AbstractThe molecular structure of dielectric elastomers dictates their mechanical, electrical, and properties to react under external stimuli, influencing their suitability for applications such as actuators, sensors, and energy harvesting devices. The molecular structure of polymers can be tailored by incorporating plasticizers and particulate fillers to achieve multifunctional properties. However, achieving a balance between flexibility and maintaining mechanical strength due to incorporation of fillers induced phase separation and compromised intermolecular interactions remains challenging. In the present work, polydimethylsiloxane (PDMS) composites are synthesized using plasticizer and particulate fillers, polyethylene glycol (H‐(OCH2CH2)nOH) and titanium diboride (TiB2) respectively in various concentrations using shear mixing and doctor blade casting technique. Molecular structure of synthesized PDMS composite is confirmed by observing peaks of Raman spectra sift, which exhibits robust CO bonds dominating for both fillers. Chain entanglement due to filler incorporation significantly affects the crosslink density of PDMS composite, it increases with the concentration of plasticizer and possesses inverse relation for particulate. Furthermore, interdependence of the filler types and concentration are found on the mechanical as well as electrical properties. The specific deformation energy exhibits a significant increase of 118.9% when comparing particulate to the plasticizer at concentration of 8 wt.%. Although plasticizer increases the actuation strain and energy conversion efficiency but decreases the electrical breakdown voltage in comparison to particulate. By systematically varying fillers concentration, subtle changes in multifunctional properties are achieved. Overall, this investigation provides a framework for tailoring dielectric elastomer composites with desired electromechanical characteristics through the amalgamation of filler types and crosslinking densities, all intricately tied to the molecular architecture for electromechanical sensors.Highlights Filler incorporation changes DE molecular structure and materials properties. Formation of additional bonds and micro‐capacitors in DE enhances capacitance. Actuation strain in DE depends on filler type and concentration. Energy conversion efficiency varies with the concentration of filler.

Hydration effects on molecular structure, vibrational, electronic properties, drug-likeness analysis, molecular docking, and molecular dynamics studies of (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one

This study examines how solvation models, including COSMO, CPCM, PCM, and SMD, affect the conformations, molecular structure, vibrational behaviors, and electronic properties of the (Z)-3-(2-oxo-2-phenylethylidene)indolin-2-one (Z3-2O2PEI) molecule within the framework of the B3LYP/cc-pVTZ model chemistry, along with its potential effectiveness as a drug for treating COVID-19. The most stable molecular conformation of the studied coùpound was identified in the presence of the COSMO solvent. The theoretical vibrational frequencies matched the experimentally observed FT-IR and Raman data. Solvent influences on the UV–vis spectra of Z3-2O2PEI revealed electronic transitions from n to π* and π to π* orbitals, along with evidence of intermolecular charge transfer (ICT) supported by analyses of Frontier Molecular Orbitals (FMO) and Natural Bond Orbitals (NBO). The examinations of Mulliken atomic charge distributions and molecular electrostatic potential surfaces reveal the electrophilic and nucleophilic sites of the molecule under study. Non-covalent Interaction (NCI) analysis confirmed the presence of steric effects and Van der Waals interactions within the compound. According to molecular docking studies, the Z3-2O2PEI molecule exhibits significant binding affinity for PLpro, a protein targeted in COVID-19 treatment. This finding is supported by subsequent molecular dynamics analysis, validating the docking results.

Structural, quantum chemical, spectroscopic (UV, FT-IR, and NMR), and molecular docking studies of novel azo compounds

A set of novel azo compounds were created, and their structures were identified using spectroscopic methods such as FT-IR, 13C NMR, 1H NMR, and HR-MS. The DFT/TD-DFT approach using the B3LYP/6–311++G(d,p) was employed to calculate the molecular structure and electronic properties of novel azo compounds. Comparative analysis has been conducted between theoretical spectral data and experimental data, revealing a significant degree of concordance. An analysis was performed on the vibrational frequencies (IR), UV–vis absorption wavelengths, and NMR chemical shifts of novel azo compounds. Furthermore, molecular docking analyses were conducted to examine the interactions between the 1M17 and 4ASD target proteins and newly synthesized azo compounds. The docking results suggest that the azo compounds have the potential to be formulated into a cancer therapeutic.

Effect of wheat TaDOF6 overexpression on the molecular structure and physicochemical properties of grain starch and resistant starch

This study examined the effects of overexpressing the DOF (DNA binding with one finger protein) transcription factor gene, TaDOF6, on wheat grain native starch and Ⅲ-type resistant starch (RS3). Overexpression of TaDOF6 in the endosperm resulted in a significant increase in amylopectin content, particularly in long-branched chains, as well as larger starch particle size. Additionally, there was an increase in both rapidly and slowly digestible starches, along with an elevated level of native resistant starch. The enhanced crystallinity and orderliness of native starch, along with improved pasting properties, were also observed. However, TaDOF6 overexpression negatively impacted RS3 by reducing its crystal order, thermal stability, and pasting performance. Principal component analysis highlighted the substantial role of amylopectin in determining the crystal structure and physicochemical properties of starch. Moreover, a significant correlation was found between the particle size of RS3 and its physicochemical characteristics. Overall, these findings demonstrate that TaDOF6 overexpression alters the composition of grain starch, leading to improvements in its molecular structure and physicochemical properties.

Rifaximin: A Comprehensive Review of Structure, Uses, Mechanisms of Action, and Assay Methods

Rifaximin, a derivative of rifamycin, has emerged as a promising therapeutic tool in gastroenterology. This review explores rifaximin's intricate molecular structure and pharmacokinetic properties, highlighting its minimal systemic absorption and targeted action within the gut. The multifaceted mechanisms of action, including direct antibacterial effects and modulation of gut microbiota, are discussed. The review then examines the efficacy of rifaximin in treating various gastrointestinal disorders like traveler's diarrhea, Irritable Bowel Syndrome with Diarrhea (IBS-D), and Small Intestinal Bacterial Overgrowth (SIBO). Dosage recommendations and the well-tolerated safety profile of rifaximin are presented. Finally, the importance of quality control measures using techniques like HPLC and spectroscopy is emphasized to ensure the drug's effectiveness and safety.