A quantum chemistry investigation of a potential inhibitory drug against the dengue virus

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56562-56570 ◽  
Author(s):  
G. S. Ourique ◽  
J. F. Vianna ◽  
J. X. Lima Neto ◽  
J. I. N. Oliveira ◽  
P. W. Mauriz ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Dengue Virus ◽  
Interaction Energy ◽  
Serine Protease ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Inhibitory Drug

The total interaction energy of the inhibitor Bz-nKRR-H bound to a serine protease of the dengue virus is mainly due to the action of Asn152, Met49, Tyr161, Asp129 and Gly151 (Met84, Met75, Asp81, Asp79 and Asp80) residues at the NS3 (NS2B) subunit.

Zeta-Potential Investigation and Experimental Study of Nanoparticles Deposited on Rock Surface To Reduce Fines Migration

SPE Journal ◽  
2013 ◽  
Vol 18 (03) ◽  
pp. 534-544 ◽  
Author(s):  
M.. Ahmadi ◽  
A.. Habibi ◽  
P.. Pourafshary ◽  
S.. Ayatollahi
Keyword(s):  
Zeta Potential ◽  
Interaction Energy ◽  
Fine Particles ◽  
Rock Surface ◽  
Production Engineering ◽  
Release Process ◽  
Fines Migration ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Potential Test

Summary Fines migration is a noticeable problem in petroleum-production engineering. Plugging of throats in porous media occurs because of detachment of fine particles from sand surfaces. Thus, the study of interactions between fines and pore surfaces and the investigation of governing forces are important factors to consider when describing the mechanism of the fines-release process. The main types of these forces are electric double-layer repulsion (DLR) and London–van der Waals attraction (LVA). It may be possible to alter these forces with nanoparticles (NPs) as surface coatings. In comparison with repulsion forces, NPs increase the effect of attraction forces. In this paper, we present new experiments and simple modeling to observe such properties of NPs. For this purpose, the surfaces of pores were coated with different types of NPs: magnesium oxide (MgO), silicon dioxide (SiO2), and aluminum oxide (Al2O3). A zeta-potential test was used to examine changes in the potential of the pore surfaces. Total interaction energy was then mathematically calculated to compare different states. Total interaction energy is a fitting criterion that gives proper information about the effect of different NPs on surface properties. Consequently, total interaction plots are found to be suitable tools for selecting the best coating material. On the basis of experimental results, the magnitude of change in zeta potential for the MgO NP was 45 mV. Our model demonstrated that the magnitude of the electric DLR in comparison with the LVA of the probe and plate surface was considerably diminished when MgO NPs were used to coat the surface of the plate, which agrees completely with our experimental observation.

DISTRIBUTION OF POINT CHARGES ON A THIN CONDUCTING DISK

2000 ◽  
Vol 11 (05) ◽  
pp. 891-900 ◽  
Author(s):  
H. OYMAK ◽  
Ş. ERKOÇ
Keyword(s):  
Interaction Energy ◽  
Coulomb Potential ◽  
Minimum Energy ◽  
Total Interaction Energy ◽  
Thin Conducting ◽  
Total Interaction ◽  
Energy Configurations

We investigate the minimum energy configuration of N equal point charges interacting via the Coulomb potential 1/r, and placed on an infinitely thin conducting disk. By minimizing total interaction energy, we obtain numerically the minimum energy configurations from which the rules for the distribution of charges on the disk are obtained.

The Mechanism of Activated Sludge Flocculation under Al3+ Dosin

2014 ◽  
Vol 675-677 ◽  
pp. 106-110
Author(s):  
Wan Lin Zheng ◽  
A Sheng Cao ◽  
Yue Wen ◽  
Hai Rong Chen ◽  
Qi Zhou
Keyword(s):  
Zeta Potential ◽  
Activated Sludge ◽  
Interaction Energy ◽  
Equivalent Dose ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Total Interaction Energy ◽  
Total Interaction ◽  
Continuous Dosing ◽  
Opposite Tendency

The mechanism governing activated sludge flocculation under Al3+ dosing was studied in this paper. Activated sludge was cultivated in sequencing batch reactors (SBR) at 22°C. Batch dosages of Al3+ were 0.00, 0.125, 0.5, 1 and 1.5meq/L respectively, and continuous dosage was 0.1meq/L. As batch dosage increased, the total interaction energy, zeta potential and turbidity tended to decline, which suggested that batch dosing promoted sludge flocculation. Under the equivalent dose, the zeta potential of continuous dosing was higher, while the LB-EPS content showed the opposite tendency and turbidity reduction was similar. Both batch and continuous dosing promoted flocculation performance: in terms of interaction energy, batch dosing was more effective; while in terms of EPS, it was on the contrary.

Modeling the Precipitation of Polydisperse Nanoparticles Using a Total Interaction Energy Model

2011 ◽  
Vol 115 (11) ◽  
pp. 4603-4610 ◽  
Author(s):  
Steven R. Saunders ◽  
Mario R. Eden ◽  
Christopher B. Roberts
Keyword(s):  
Interaction Energy ◽  
Energy Model ◽  
Total Interaction Energy ◽  
Total Interaction

The use of nanotechnology to prevent and mitigate fine migration: a comprehensive review

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Madadizadeh ◽  
Alireza Sadeghein ◽  
Siavash Riahi
Keyword(s):  
Porous Media ◽  
Zeta Potential ◽  
Interaction Energy ◽  
Production Equipment ◽  
Petroleum Reservoir ◽  
Comprehensive Review ◽  
Total Interaction Energy ◽  
Initial Injection ◽  
Total Interaction ◽  
Core Flood

AbstractFine migration is a serious problem in petroleum reservoir that causes damage to the reservoir and production equipment. One of the methods to solve this problem is using nanotechnology. Nanoparticles can reduce fine migration by various mechanisms such as reducing the zeta potential, changing the total interaction energy between surfaces, pH, and roughness of the particle’s surfaces. This study presents a review of the methods such as sand pack test, core flood test, and proppant test that study the nanoparticles’ influence on fine migration. Also, there are two different scenarios for the use of nanoparticles to mitigate fine migration. One of these scenarios is the co-injection of nanoparticles and particles suspended fluid, and another scenario is the initial injection of nanoparticles into the porous media (pre-flush). The results of the studies have shown that pre-flush of nanoparticles has a better effect on the control of fine migration.

scholarly journals Quantitative Analysis of Membrane Fouling Mechanisms Involved in Microfiltration of Humic Acid–Protein Mixtures at Different Solution Conditions

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1306 ◽  
Author(s):  
Chunyi Sun ◽  
Na Zhang ◽  
Fazhan Li ◽  
Guoyi Ke ◽  
Lianfa Song ◽  
...  
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Interaction Energy ◽  
Membrane Fouling ◽  
Calcium Ion ◽  
Ion Concentration ◽  
Total Interaction Energy ◽  
Quantitative Understanding ◽  
Total Interaction ◽  
Calcium Ion Concentration

A systematical quantitative understanding of different mechanisms, though of fundamental importance for better fouling control, is still unavailable for the microfiltration (MF) of humic acid (HA) and protein mixtures. Based on extended Derjaguin–Landau–Verwey–Overbeek (xDLVO) theory, the major fouling mechanisms, i.e., Lifshitz–van der Waals (LW), electrostatic (EL), and acid–base (AB) interactions, were for the first time quantitatively analyzed for model HA–bovine serum albumin (BSA) mixtures at different solution conditions. Results indicated that the pH, ionic strength, and calcium ion concentration of the solution significantly affected the physicochemical properties and the interaction energy between the polyethersulfone (PES) membrane and HA–BSA mixtures. The free energy of cohesion of the HA–BSA mixtures was minimum at pH = 3.0, ionic strength = 100 mM, and c(Ca2+) = 1.0 mM. The AB interaction energy was a key contributor to the total interaction energy when the separation distance between the membrane surface and HA–BSA mixtures was less than 3 nm, while the influence of EL interaction energy was of less importance to the total interaction energy. The attractive interaction energies of membrane–foulant and foulant–foulant increased at low pH, high ionic strength, and calcium ion concentration, thus aggravating membrane fouling, which was supported by the fouling experimental results. The obtained findings would provide valuable insights for the quantitative understanding of membrane fouling mechanisms of mixed organics during MF.

Ab initio study of the (BH)2 dimer

1980 ◽  
Vol 45 (12) ◽  
pp. 3270-3282 ◽  
Author(s):  
Miroslav Urban ◽  
Soňa Hrivnáková ◽  
Pavel Hobza
Keyword(s):  
Perturbation Theory ◽  
Ab Initio ◽  
Interaction Energy ◽  
Multipole Expansion ◽  
Coulomb Energy ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Linear Arrangement ◽  
Total Interaction Energy ◽  
Total Interaction

The total interaction energy between two BH molecules was calculated as a sum of the SCF and correlation interaction energies. The latter was obtained either semiempirically or by the 2nd and 3rd order perturbation theory. It appeared to be the main contribution to the total interaction energy with some geometries. Important differences in the SCF interaction energy of different geometrical configurations of the dimer were explained by the utilization of higher terms of the Coulomb energy multipole expansion. Unexpectedly the geometry of highest stability does not correspond to the linear arrangement of the dimer but rather to the T-shaped structure.

scholarly journals In Silico Study of Pacific oyster Antiviral Polypeptides as Potential Inhibitory Compounds for SARS-CoV-2 Main Protease

2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Mehrdad Mohammadi ◽  
Sajjad Rajabi ◽  
Ahmad Piroozmand ◽  
Seyed Ali Mirhosseini
Keyword(s):  
Molecular Docking ◽  
Interaction Energy ◽  
Pacific Oyster ◽  
Data Bank ◽  
Positive Control ◽  
Protein Data Bank File ◽  
Total Interaction Energy ◽  
Molegro Virtual Docker ◽  
Main Protease ◽  
Total Interaction

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel pathogen that has triggered a pneumonia outbreak, and despite the measures, the pandemic still continues to occur. Objectives: The molecular docking analysis was used to test whether the human immunodeficiency virus 1 (HIV-1) protease inhibitory peptides. These marine polypeptides were isolated from the hydrolysate of Pacific oyster. Methods: Molecular docking process was performed using Molegro Virtual Docker software. The protein data bank file of the crystal structure of COVID-19 main protease in complex with an inhibitor N3 (ID 6LU7) was obtained from the PubChem data source. After preparing protein and removing water and internal ligand, the major cavity was selected for the next step, the docking procedure. Afterward, the MolDock score, Rerank score, Total interaction energy (between energy), and HBond item were calculated. The Remdesivir was used as a positive control in the docking project. Results: The results of the docking step were evaluated based on several bioinformatics docking scores, including MolDock score, Rerank score, Total interaction energy (between energy), and HBond. The hydrogen bond of remdesivir was -6.03673, and Leu-Leu-Glu-Tyr-Ser-Ileu polypeptide was -6.44185. The Rerank score of remdesivir was -98.9254 and for Leu-Leu-Glu-Tyr-Ser-Ileu polypeptide was -107.821. Of the two screened Pacific oyster polypeptides, the score of Leu-Leu-Glu-Tyr-Ser-Ileu ligand was higher than remdesivir. Conclusions: This study demonstrated that Pacific oyster compounds may have the potency to be evolved as an anti-COVID-19 main protease drug to fight against the novel coronavirus; however, preclinical and clinical trials are needed for further experimental and/or clinical scientific validation.

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