Electrostatic Analysis Research Articles

Physical‐organic aspects along with linear and nonlinear optical properties of benzene sulfonamide compounds: In silico analysis

AbstractThe sulfonamides class of drugs is known due to superb biological and notable nonlinear optical (NLO) applications. The current study reports detailed computational and spectroscopic studies of 16 novel benzene sulfonamides compounds. Computational studies on these compounds (1–16) have been performed with the aid of density functional theory (DFT) at B3LYP/6‐31G (d,p) basis set. B3LYP with the conjunction of 6‐31G(d,p) has been used to gain optimized geometries of these compounds. Different key parameters have been performed to analyze the structural‐property relationship, stability, reactivity, charge transferability, and NLO response of these novel compounds. Electronic properties including frontier molecular orbitals (FMOs) alignment, natural bond orbital (NBO) analysis, spectroscopic fourier‐transform infrared spectroscopy (FT‐IR), and NLO properties were calculated using B3LYP/6‐31G(d,p) and M06‐2X/6‐31G(d,p) basis sets. Natural bonding orbital analysis confirmed the successful electron transferability between donor moiety and acceptor moiety. The molecular electrostatic potential analysis unveils the intramolecular hydrogen bonding along with different reactive sites in these compounds 1–16. Global indices of reactivity were analyzed using energies of frontier molecular orbitals of compounds 1–16, which suggested that these compounds are chemically hard and stable compounds. Absorption maxima of all compounds were estimated with aid of time‐dependent DFT at B3LYP/6‐31G(d,p) basis set which disclosed the best agreement between experimental and DFT‐based recorded spectra. FT‐IR analysis (at B3LYP/6‐31G(d,p)) confirmed different modes of vibration in all the title compounds and also exhibit a concrete relation with experimentally recorded IR spectrums. Moreover, all the compounds (1–16) show good NLO response. NLO responses of 1–16 compounds were computed at the same level of B3LYP/6‐31G (d,p), which is found to be greater than the standard molecule. All these analyses suggest that 1–16 benzene sulfonamides compounds are found to be suitable candidates for biological and NLO applications.

Molecular mechanisms of cardiac actomyosin transforming from rigor state to post-rigor state.

Sudden cardiac death contributed to half of all deaths from cardiovascular diseases. The mechanism of the kinetic cycle of cardiac myosin is crucial for heart protection and drug development. The state change in the myosin kinetic cycle from the rigor state to the post-rigor state is fundamental to explain binding and dissociation. Here, we used β-cardiac myosin in the rigor and post-rigor states to model the actomyosin complexes. Molecular dynamics simulations, electrostatic analysis, and energetic analysis of actomyosin complexes were performed in this work. The results showed that there are fewer interactions and lower electrostatic binding strength in the post-rigor state than in the rigor state. In the post-rigor state, there were higher free binding energy, fewer salt bridges, and fewer hydrogen bonds. The results showed a lower binding affinity in the post-rigor state than in the rigor state. The decrease in the binding affinity provided important conditions for dissociation of the myosin from the actin filament. Although previous studies focused mostly on the binding process, this study provides evidence of dissociation, which is even more important in the myosin kinetic cycle. This research on the mechanism of myosin kinetic cycles provides a novel direction for future genetic disease studies.

Density functional theoretical study, spectroscopic characterization and molecular docking of the diuretic drug, spironolactone, adsorbed on AuNPs surface and in-vitro studies based on anticancer activity studies against A549 lung cancer cell line

In this study, the geometry, intramolecular charge transfer interactions, and harmonic vibrational frequencies of the diuretic drug, Spironolactone (SPL) and SPL adsorbed on gold nanoparticle (SPLA molecule) were investigated with the help of density functional theory method. Both molecules were found to be stabilized by intramolecular hydrogen bonds C7-H37. O27 and C16-H47. O2, as well as intramolecular charge transfer interactions. These interactions were quantitatively confirmed using natural localized molecular orbitals (NLMOs) analysis. The frontier molecular orbital analysis provided a comparative picture of the reactivity, showing a low value of the energy gap, revealing electron transport in the molecule. The most reactive sites of the molecules were predicted by the molecular electrostatic potential map analysis together with the study of local and global reactivity descriptors. FT-IR and Raman spectral analysis confirmed the existence of significant hydrogen bonding, and charge delocalization in the molecules. Molecular docking performed for the biological activity screening of both molecules along with the SERS and MTT assay (in vitro) analysis confirmed their cancer activity. All the comparative results lead to the conclusion that SPLA possess enhanced therapeutic activity than SPL and hence can be used for effective label-free monitoring of cells in-vitro.

An electrostatic finite element analysis of the electrospinning process of bilayer constructs using a parallel-plate collector

Fundamental knowledge of the deposition process of electrospun fibers is of paramount importance to the fabrication of constructs with fibers oriented in specific directions, depending on the mandrel geometry. This paper presents an electrostatic finite element analysis of a parallel-plate electrospinning configuration that reveals the effects of the electric potential intensity and directionality on the deposition of aligned and randomly oriented fibers, resulting in the formation of a fibrous bilayer construct. Simulations demonstrate that polymer deposition between the collector plates yields a local effect on the electric field. This study provides a computational methodology for investigating other collector configurations and guidance for designing electrospinning setups capable of producing microfibrous constructs with tailored morphologies.

Design and Simulations of High-Sensitivity Multi-Directional Inertial Sensor

This paper proposed the high sensitive linear and rotational based differential capacitive inertial sensor. The designed sensor consists of a proof of mass, which resides in an air medium — the acceleration measured along with a change of displacement and the differential capacitance. Sensor modeling and simulation have done with CoventorWare software. SOIMUMPS fabrication process has described because it allows pattern on both sides of an SOI wafer. Solid mechanics and electrostatic analysis have applied for measurement of acceleration. The high sensitivity of 981.28fF/g has observed. The simulated results have tabulated. Finally, performance and future scope of the inertial sensor has discussed.

Electrostatic Potential Distribution Analysis of Silicon Nanowire Field Effect Transistor with Various Channel Length

Silicon nanowire FET plays a vital role in building of nanoscale electronic device applications. In this article, the silicon nanowire field effect model is designed with different channel lengths. By using the SiNW FET device model, various electrostatic potential distribution studies are done. This SiNW FET model is reducing the complexity in design. Two types of the device geometries are studied by changing the silicon nanowire channel length as 1000 nm and 200 nm. The 1000 nm channel provides high penetration to the active region of the nanowire FET than the 200 nm channel. This silicon nanowire FET model can apply to many nanoscale biochemical elements sensing applications.

Quantum Chemical Computations of an Efficient Push-Pull NLO Chromophore 3-[4-Nitrophenyl Azo]- 9H- Carbazole-9-Ethanol

Electric-optic (EO) materials are being explored for applications ranging from fiber and satellite telecommunications, optical gyroscopes, to photonic detection of radar etc. Dipolar push-pull Organic chromophores that exhibit extended π-conjugation, in particular, show enhanced second order NLO properties. The present investigation reports the quantum chemical computations of the high efficiency push-pull NLO molecule 3-[(4-Nitrophenyl Azo)] - 9H-Carbazole-9-Ethanol (NPACE). The organic push-pull molecule is optimized in gaseous and in various solvent condition using Exchange correlation function (B3LYP/MP2). Molecular electrostatic potential, thermal properties and NBO analysis have also been performed in detail. The effective electron cloud moment in the molecule is mainly governed by the physical process termed intramolecular Charge Transfer (ICT).

Synthesis, spectroscopic characterization, molecular docking and in vitro cytotoxicity investigations on 8-Amino-6-Methoxy Quinolinium Picrate: a novel breast cancer drug

Density Functional Theory (DFT) studies of the 8-Amino-6-Methoxy Quinolinium Picrate (8A6MQP) molecule have been carried out with extensive and accurate investigations of detailed vibrational and spectroscopic investigations as well as validated experimentally. The 8A6MQP sample was synthesized and characterized using FT-IR, FT-Raman, FT-NMR and UV-Vis spectroscopic techniques. Subsequently, the optimized molecular structure and harmonic resonance frequencies of the molecule were computed based on DFT/B3LYP method with a 6-311G++(d,p) basis set using the Gaussian 09 program. The experimental and calculated vibrational wavenumbers were assigned. The absorption spectrum of the molecule was computed in the liquid phase (ethanol), which exhibits n to л* electronic transition and compared with the observed UV-Vis spectrum. Frontier molecular orbital analysis shows the molecular reactivity and kinetic stability of the molecule. The Mulliken atomic charge distribution and molecular electrostatic potential surface analysis of the molecule validate the reactive site of the molecule. The natural bond orbital analysis proves the bioactivity of the molecule. Molecular docking analysis indicates that the 8A6MQP molecule inhibits the action of DNA topoisomerase 2-alpha protein, which is associated with breast cancer. In addition, the in vitro cytotoxicity analysis of the 8A6MQP molecule against human cervical cancer cell lines (ME180) and human breast cancer cell lines (MDA MB 231) were determined by MTT assay, which evidences that the title molecule exhibits higher inhibition against the breast cancer cell lines compared to that of cervical cancer cell lines. Hence, the present study paves the way for the development of novel drugs in the treatment of breast cancer. Communicated by Ramaswamy H. Sarma

Multi-objective optimization and extraction mechanism understanding of ionic liquid assisted in extracting essential oil from Forsythiae fructus

Presently, the essential oils are obtained by hydro-distillation, which demand long extracting time and great energy. Consequently, efficiently obtaining essential oils needs to be considered. In this work, microwave-assisted ionic liquids treatment followed by hydro-distillation (MILT-HD) is used to extract essential oils. The purpose is to use the multivariate analysis model to investigate the effects of process parameters on extraction efficiency and explore the mechanism for enhancing extraction yields. Through multi-objective optimization, optimum parameters are ionic liquid ratio of 70.00%, irradiation time of 6.00 min and irradiation power of 30.00%. Under these conditions, MILT-HD can significantly increase the extraction efficiency. And it can reduce energy demands. Furthermore, the mechanism for efficient extraction is innovatively explored by electrostatic potential analysis and temperature profile. The ionic liquid has a strong interaction with cellulose, and can better absorb microwave energy and quickly convert it into heat. Under the synergistic interactions of ionic liquids-cell wall and ionic liquids-microwave, the MILT-HD can strongly destroy the cell wall structure. It makes the essential oil efficiently diffuse. Based on this work, it provided a way to obtain Forsythiae fructus essential oils efficiently. And It is helpful to improve the comprehensive understanding of the extraction process of MITL-HD.

Simulation and dynamic control of removal phenols from coal gasification wastewater by synergistic extraction

Coal chemical wastewater has a high organic content and poor biochemical performance. The phenolic substances in wastewater cannot meet the discharge standard, which damages the environment and endangers human health. In this study, to remove phenolic substances from coal chemical wastewater, a process of dephenol treatment was studied, which integrated the selection of extractant, process simulation, and dynamic control. In view of the low removal rate of polyphenols, a new extraction solvent was designed to reduce the polyphenol content. The four synergistic extraction solvents of Mesityl oxide + n-pentanol, MPK + n-pentanol, MIPK + n-pentanol, and MIBK + n-pentanol were optimized and calculated by molecular simulation, and electrostatic potential analysis, NBO analysis, interaction energy analysis, and non-covalent interaction analysis were used to elucidate the nature of the synergy between molecules. The results show that the interaction energy of mesityl oxide + n-pentanol + phenol and mesityl oxide + n-pentanol + catechol is higher than other solvents, which are − 46.13 kJ mol−1 and − 40.36 kJ mol−1, respectively. The difference of the interaction energy of mesityl oxide + n-pentanol + phenol and mesityl oxide + n-pentanol + water is − 14.30 kJ mol−1 and that of mesityl oxide + n-pentanol + catechol and mesityl oxide + n-pentanol + water is −8.53 kJ mol−1, which shows the superiority of mesityl oxide + n-pentanol for the extraction and recovery of phenols. The results showed that the extraction performance of the synergistic extractants is stronger than that of the single extractants. Aspen Plus software was used to simulate the extraction and recovery of phenols with mesityl oxide + n-pentanol as the extractant, and the operation parameters were optimized with the smallest total annual cost as the target. The amount of fresh extractant added is only 0.95 kg/h, and the removal rate of phenol and catechol reached 99.95% and 97.97%, respectively, and the total phenol concentration dropped from 6499 mg/L to 56 mg/L. In addition, the little difference between experimental data and simulation results also indicates that mesityl oxide + n-pentanol is an effective extraction solvent. Finally, Aspen dynamic simulation investigated the dynamic response results under disturbances in the feed flow rate and feed component, and the results showed that the process operation under disturbances can quickly restore a stable value. The control scheme is effective.

Synthesis, structural, spectroscopic and docking studies on (E)-1-Ferrocenyl-3-phenyl­propen-1-one by the density functional theory

ABSTRACT The complete geometrical parameters of the synthesised compound (E)-1-Ferrocenyl-3-phenyl­propen-1-one were calculated by the Density Functional Theory method. The Fourier-transform infrared spectra and Fourier-transform -Raman spectra of (E)-1-Ferrocenyl-3-phenyl­propen-1-one molecule were analysed by comparing the experimental results with the theoretical calculations. Natural bond orbital analysis analyses the intramolecular contacts of (E)-1-Ferrocenyl-3-phenyl­propen-1-one molecule. Ultraviolet–visible spectra of the (E)-1-Ferrocenyl-3-phenyl­propen-1-one molecule have been recorded, and the electronic properties have been computed with the time-dependent density functional theory method. The chemical reactive sites have been revealed by the Fukui function and molecular electrostatic potential analysis. Docking studies were performed for (E)-1-Ferrocenyl-3-phenyl­propen-1-one molecule using the molecular docking software with four topoisomerasesfrom Protein Data Bank. In vitro antibacterial assay showed inhibitive growth of (E)-1-Ferrocenyl-3-phenyl­propen-1-one molecule against bacterial pathogens staphylococcus aureus and pseudomonas aeruginosa.

Synthesis, growth, DFT, and HOMO-LUMO studies on pyrazolemethoxy benzaldehyde single crystals

Pyrazolemethoxy benzaldehyde (PMB) was synthesized and crystals were grown by slow evaporation solution growth method. PMB was crystallized in a monoclinic crystal system with a centrosymmetric C2/c space group, according to single-crystal X-ray diffraction analysis. The crystalline planes were identified using powder X-ray diffraction analysis. FTIR - FT-Raman spectroscopic techniques were performed to determine the vibrational modes of functional groups for the grown crystal. UV-visible spectral analysis and photoluminescence studies were taken to investigate the linear optical properties of the grown crystal. Thermogravimetric and differential thermal analysis (TG/DTA) were used to determine the thermal stability of the PMB crystal. In addition to this density functional theory (DFT) calculations such as frontier molecular orbital's (FMOs), global chemical reactivity parameters, hyperpolarizability, natural bond orbital (NBO) analysis, Mullikan atomic charge distribution, and molecular electrostatic potential map analysis were carried out in gaseous phase using B3LYP/6-311G* basis set.

Systematic study of cooperative interplay between single-electron pnicogen bond and halogen bond in X3C···PH2Y···ClY (X=H, CH3; Y=CN, NC) complexes in two different minima configuration

UMP2 calculations with aug-cc-pVTZ basis set used to analyse intermolecular interactions in X3C···PH2Y···ClY (X = H, CH3; Y = CN, NC) complexes constructed via halogen bond and single-electron pnicogen bond in two discovered minima in the potential energy surface. The first minima presents short P−C distances and, in all cases, high interaction energies compared to the second one that shows long P−C distances with a typical weak pnicogen bond interaction. The impacts of the halogen bonds on the single-electron pnicogen interaction in each complex are systematically investigated by the means of cooperative effects. In all cases studied, a favorable cooperativity is observed but these values are much higher for first minima, which ranges from −19.73 to −36.82 kJ mol−1, than second minima with cooperative energy values between −0.75 and −4.69 kJ mol1. In order to unveil the mechanism of the cooperativity, these effects are analysed in terms of geometric, energetic, electrostatic potential analysis, electron charge density analysis performed using (QTAIM), many-body interaction analysis and electron density analysis.

Analytical and experimental studies on 245 kV gas insulated surge arrester

The voltage distribution across gas insulated surge arrester (GISA) is highly non-uniform as compared to conventional porcelain-clad surge arresters. The aim of the present paper is to optimize design of grading shield in such a way that the non-uniformity voltage factor across GISA must be less than ±10%. To achieve this order of non-uniformity factors, special grading shields like window based cylindrical and conical shields are proposed. In the present paper, 245 kV GISA model has been considered to analyze voltage distribution across the metal-oxide (MO) blocks. The electrostatic field and voltage distribution analyses are carried out on surge arrester by considering various shield configurations using numerical techniques. Further, design of shield and development is verified by performing dielectric duties on GISA assembly without MO blocks as per IEC 62,271–203. The lightning and switching impulse discharge current tests were carried out on the developed 245 kV GISA residual voltages were recorded. These voltage levels for above discharge currents are found to be in the order of 2.8 – 3.2 p. u. and are at acceptable levels as per IEC 60,099–4. Finally, protection level or V-I characteristics of GISA is established by measuring residual voltages for the entire current range.

Electrostatic Charges of Abrasive Powders: The Role of Particle Size and Humidity

Electrostatically coated abrasives have drawn vast attention in many industrial applications. Therefore, influence of humidity on the electrical properties of α-SiC and α-Al2O3 abrasive powders with three μm-range particle sizes are here investigated using electrostatic charge and DC resistivity analysis. From the three particle size ranges used, 15–16 μm, 60–63 μm and 153–156 μm, the intermediate one (60–63 μm) is found to be associated with the highest charge values, measured using a double Faraday cup method, as well as the highest resistivity for both materials. However, comparing SiC and Al2O3 powders, the latter ones present about twice larger charges in dry and normal humidity states accompanied by several orders of magnitude larger resistivity. Under humid conditions all the powders reveal diminishing charge and resistivity values.

The differential analysis for temperature distribution diagnostics of arc current-carrying region in sheet slanting tungsten electrode inert gas welding with the electrostatic probe

Abstract An electrostatic probe differential analysis method is used to diagnose the arc current-carrying region of the sheet slanting tungsten electrode. Based on the local thermal equilibrium condition and energy transition model with charged particles collision, the temperature distribution in the current-carrying region of different welding process parameters is solved by saturated ion current. The results show that the temperature distribution range in the width direction of sheet slanting tungsten electrode expands, the arc high-temperature region shifts integrally, and the temperature in the thickness direction of sheet slanting tungsten electrode would be symmetrical. The guide effect of the hypotenuse of sheet slanting tungsten electrode for arc current and the inertia drag effect of arc would mainly change the temperature distribution. The variation of the inclination angle of the hypotenuse of sheet slanting tungsten electrode will aggravate the shift of the arc high-temperature region. The larger inclination angle will enhance the guiding effect, and then the inertia drag effect would be in a dominant position with a smaller inclination angle. With the increase of welding current, both the arc stiffness and the guiding effect would be intensified, the latter should make the arc high-temperature zone shift to the position with a small discharge gap.

DiffBond: A Method for Predicting Intermolecular Bond Formation.

Many tools that explore models of protein complexes are also able to analyze interactions between specific residues and atoms. A comprehensive exploration of these interactions can often uncover aspects of protein-protein recognition that are not obvious using other protein analysis techniques. This paper describes DiffBond, a novel method for searching for intermolecular interactions between protein complexes while differentiating between three different types of interaction: hydrogen bonds, ionic bonds, and salt bridges. DiffBond incorporates textbook definitions of these three interactions while contending with uncertainties that are inherent in computational models of interacting proteins. We used it to examine the barnase-barstar, Rap1a-raf, and Smad2-Smad4 complexes, as well as a subset of protein complexes formed between three-finger toxins and nAChRs. Based on electrostatic interactions established by previous experimental studies, DiffBond was able to identify ionic and hydrogen bonds with high precision and recall, and identify salt bridges with high precision. In combination with other electrostatic analysis methods, DiffBond can be a useful tool in helping predict influential amino acids in protein-protein interactions and characterizing the type of interaction.

Synthesis & characterization of heterocyclic disazo - azomethine dyes and investigating their molecular docking & dynamics properties on acetylcholine esterase (AChE), heat shock protein (HSP90α), nicotinamide N-methyl transferase (NNMT) and SARS-CoV-2 (2019-nCoV, COVID-19) main protease (Mpro)

In the study, by using 5-amino-4-arylazo-3-methyl-1H-pyrazole derivatives and 2‑hydroxy-5-(phenyldiazenyl) benzaldehyde; eight novel heterocyclic disperse disazo-azomethine dyes were synthesized, their chemical structures were characterized via FT-IR and 1H NMR studies. Synthesized compounds were also investigated computationally by performing various techniques. In the computational part of the study, geometry optimizations, frequency analyses, frontier molecular orbital (FMO) calculations, molecular electrostatic potential (MEP) map calculations, FT-IR and NMR spectral analyses were performed on the compounds. Additionally, to reveal their potentials against SARS-CoV-2 main protease (SARS-CoV-2 Mpro), acetylcholine esterase (AChE), heat shock protein (HSP90α) and nicotinamide N-methyl transferase (NNMT), molecular docking calculations were also performed on the synthesized compounds. Molecular dynamics (MD) simulations were carried out on the top-scoring ligand-receptor complexes to evaluate the stability of the complexes and the interactions between ligands and receptors in more detail. Results showed that synthesized compounds can interact with all these four receptors effectively and can be promising structures for further studies.

Electrostatic Potential Analysis in Polyelectrolyte Brush-Grafted Microchannels Filled with Polyelectrolyte Dispersion

In this study, the model framework that includes almost all relevant parameters of interest has been developed to quantify the electrostatic potential and charge density occurring in microchannels grafted with polyelectrolyte brushes and simultaneously filled with polyelectrolyte dispersion. The brush layer is described by the Alexander-de Gennes model incorporated with the monomer distribution function accompanying the quadratic decay. Each ion concentration due to mobile charges in the bulk and fixed charges in the brush layer can be determined by multi-species ion balance. We solved 2-dimensional Poisson–Nernst–Planck equations adopted for simulating electric field with ion transport in the soft channel, by considering anionic polyelectrolyte of polyacrylic acid (PAA). Remarkable results were obtained regarding the brush height, ionization, electrostatic potential, and charge density profiles with conditions of brush, dispersion, and solution pH. The Donnan potential in the brush channel shows several times higher than the surface potential in the bare channel, whereas it becomes lower with increasing PAA concentration. Our framework is fruitful to provide comparative information regarding electrostatic interaction properties, serving as an important bridge between modeling and experiments, and is possible to couple with governing equations for flow field.

Structural, spectral elucidation, wavefunctional properties, natural bond orbitals, and molecular docking analysis of synthesized 1-phenyl-3(4-methoxyphenyl)-2-propenone: protease kinase inhibitor

In this present work, structural, spectral, and electronic properties of newly synthesized 1-phenyl-3(4-methoxyphenyl)-2-propenone compounds are examined by making the use of the density functional theory Gaussian 16 W tool. Optimized structural parameters, topological properties (Electron localization function and Localized orbital locators) are investigated in the aqueous phase. Experimental spectroscopic (Fourier transform infrared spectroscopy and Fourier transform Raman spectroscopy) investigation and quantum chemical analysis are performed on the title compound. Non-covalent interaction analysis is performed in different solutions. Bandgap energies are calculated from molecular orbital energies in various solvent atmospheres. Electrophilic site strength of headline compound is identified and analyzed from molecular electrostatic potential surface and Mulliken atomic charges analysis in different polar and non-polar liquids. Experimental and theoretical chemical shift values are recorded and predicted in a nonpolar solvent by Nuclear magnetic resonance spectral investigation. Hyperconjucative interactions are studied from the natural bond orbitals method. Drug likeness and mol inspiration properties are calculated. Moreover, a Molecular docking study is performed with breast cancer and anti-malarial receptors.