3,815 publications found
Sort by
Probing the mechanical and deformation behaviour of CNT-reinforced AlCoCrFeNi high-entropy alloy – a molecular dynamics approach

ABSTRACT This present study investigates the mechanical and deformation behaviour of pristine and carbon nanotube (CNT)-reinforced AlCoCrFeNi high-entropy alloys (HEAs) using molecular dynamics (MD) simulations. The results reveal that an increase in the atomic fraction of Al in pristine AlCoCrFeNi HEAs leads to reduced mechanical behaviour. The mechanical behaviour of the pristine AlCoCrFeNi HEAs notably improves following CNT reinforcement, particularly when using CNT with higher chirality. As the chirality of the CNT increases from (6,6) to (15,15), Young's modulus, yield stress, and toughness of the (15,15) CNT-Al20CoCrFeNi HEA enhance by 17.34%, 29.44%, and 44.44% compared to the (6,6) CNT – Al20CoCrFeNi HEA. HEAs with lower Al fractions experience more substantial stress drops due to rapid structural changes. CNT reinforcement, particularly with higher chirality, decelerates this structural transformation, enhancing yield strength greatly. The analysis of the dislocation evolution revealed that the CNT-reinforced HEA exhibits higher dislocation density compared to the pristine HEA, indicating strain hardening from CNT reinforcement. Furthermore, examination of atomic shear strain reveals confined deformation along shear bands in CNT-reinforced HEAs, leading to the deformation and eventual fracture of CNTs. This study provides valuable insights for enhancing the mechanical behaviour of CNT-reinforced AlCoCrFeNi HEAs, aiding in their design and development.

Size effects on dislocation starvation in Cu nanopillars: a molecular dynamic simulations study

ABSTRACT Size plays an important role on the deformation mechanism of nanopillars. With decreasing size, many FCC nanopillars exhibit dislocation starvation which is responsible for their high strength. However, many details about the dislocation starvation like how often it occurs, and how much is its contribution to the total plastic strain, are still elusive. Similarly, the size below which the dislocation starvation occurs is not clearly established. In this context, atomistic simulations have been performed on the compression of <110> Cu nanopillars with size (d) ranging from 5 to 21.5 nm. Molecular dynamics (MD) simulation results indicate that the nanopillars deform by the slip of extended dislocations and exhibit dislocation starvation mainly at small sizes (<20 nm). The frequency of the occurrence of dislocation starvation is highest in small-sized nanowires and it decreases with increasing size. Above the size of 20 nm, no dislocation starvation has been observed. Furthermore, we define the dislocation starvation strain and based on this, it has been shown that the contribution of the dislocation starvation to the total plastic strain decreases from 70% in small-sized nanopillars to below 5% in large-sized pillars. The present results suggest that dislocation starvation is a dominant phenomenon in small-sized nanopillars.

Open Access
Exploration of anti-tumour inhibitors from colchicine derivatives based on 3D-QSAR, molecular docking and molecular dynamics simulations

ABSTRACT Microtubulin is an important research target for anti-tumour drugs, which can be used to inhibit microtubulin polymerisation and improve the efficacy of tumour therapy. In this paper, 61 microtubule protein inhibitors with anticancer activity are selected as the data set for building a stable and effective QSAR (Topomer CoMFA) model, resulting in a Topomer CoMFA model with validation coefficients of  = 0.737 and  = 0.922. Fifteen new inhibitors with theoretically high activity are designed by screening the zinc database for new fragments with good activity through the contribution descriptors obtained by Topomer CoMFA. After simulating the binding affinity and interaction of the inhibitors with the proteins by molecular docking, all these compounds formed strong interactions such as hydrogen bonds with multiple amino acids in the receptor proteins. Furthermore, molecular dynamics results show that the predicted highly active compounds exhibited stable and favourable binding patterns to the active pocket. In addition, these new compounds exhibit good ADMET properties. The present work establishes a reliable QSAR model for computational simulation screening of microtubulin drug development and provides a basis for further access to novel microtubulin inhibitors.

In-silico and in-vitro identification of triazole based compounds as potential EGFR inhibitors targeting lung cancer

ABSTRACT The use of FDA-approved drugs for the therapy of lung cancer through drug repurposing is a noteworthy approach. We retrieved all the FDA-approved triazole-based drugs from Drugbank and conducted docking-based virtual screening of the triazole-based FDA-approved drugs against the EGFR target. Deferasirox demonstrated hydrogen bonding interactions with residues Thr 830, Asp 831, Lys 721 and Met 769 of the EGFR-TKD receptor (PDB ID: 1M17) and Posaconazole showed hydrogen bonding with residues Met 769 and Glu 734 of the similar EGFR receptor along with the binding energies of −9.60, −9.50, kcal/mol respectively. The dock score for reference molecule found to be −6.70 (kcal/mol). Best two ligands (Deferasirox and Posaconazole) were selected on the basis of dock score from the virtual screening results for in vitro NRU assay using A549 cells to determine their cytotoxicity and cell viability. During the in vitro NRU experiment, Deferasirox and Posaconazole demonstrated IC50 values of 114.9 and 910.2 µM, respectively. MD simulations were performed to investigate the dynamic behaviour and stability, and interactions were compared to the standard inhibitor for the EGFR target. DFT studies were carried out to determine their molecular properties, including their electronic structure, bond lengths and bond energies. The results of the in silico and in vitro studies were analysed to assess the potential of Deferasirox and Posaconazole for use as anticancer agents in the mitigation of lung cancer symptoms. This study focused on repurposing FDA-approved triazole-based compounds to identify their potential as effective lung cancer treatments with anticancer properties.

Identification of small-molecule glucokinase activator for type-2-diabetes treatment: a structure-based virtual screening approach

ABSTRACT Glucokinase (GK, EC is a crucial enzyme that catalyses the conversion of glucose to glucose-6-phosphate. It is used to treat type-2 diabetes (T2D), a serious metabolic disorder that is still at the forefront without proper medication. Fast Rigid Exhaustive Docking (FRED) was carried out for 400,000 compounds from the Zinc database to identify novel glucokinase activators. The hit compounds ZINC69775727, ZINC9114647, ZINC91773667, ZINC9305321, and ZINC96165848 interacted strongly with allosteric site residues and, formed hydrogen bonds with ARG 63. The hit compounds met the criterion for drug-likeness, according to the ADME prediction. The compounds were then subjected to 100 ns of molecular dynamics simulation and MM-GBSA calculation using DESMOND. The findings demonstrated that the compounds had good stability and minimal fluctuation throughout the course of the simulation, pointing to the potential of the chosen compounds for glucokinase activation. The compound ZINC69775727 in particular has the lowest binding energy of −111.1 kcal/mol, which is lower than the native ligand’s binding energy of −102.84 kcal/mol and the binding energies of the control compounds PSN-GK1 and Piragliatin, which are −102.49 kcal/mol and −107.767 kcal/mol, respectively. Therefore, the information from this work may be useful in finding novel small molecules as GKAs.