Molecular Dynamics Study Research Articles

In silico Molecular Docking and Dynamic Study of MDM2-p53 Inhibitor Alkaloids Extracted from Withania somnifera Against Tumor Growth

In today’s world, human tumor growth has become a critical health issue. Many patients experience ineffective chemotherapeutic treatments, prompting the need for alternative methods. Our recent research has explored active alkaloid extracts from Withania somnifera as potential inhibitors of the MDM2-p53 interaction, a key factor in tumor growth. Using in silico molecular docking and dynamic approaches, we identified eight effective alkaloids with high docking score are WithanolideD (–10.0Kcal/mol), Withanolide (–10.0Kcal/mol), WithaferinA ( ̶ 9.9Kcal/mol), WithanolideB ( ̶ 9.5Kcal/mol), WithalongolideA ( –9.4Kcal/mol), WithanolideE ( ̶ 9.4Kcal/mol), WithanolideA ( ̶ 9.0Kcal/mol), Withanone ( ̶ 8.9Kcal/mol). Among them, WithaferinA, WithanolideA, WithanolideD, WithanolideE, and Withanone demonstrated the most stable hydrogen bonding, stable RMSD, and RMSF. Lipinski’s rule of five, which assesses drug-like qualities, confirmed their potential through canonical SMILES verification. Molecular dynamics of the protein-ligand complex revealed that these docked complexes remain thermally stable, with consistent bond energy, dihedral angles, and stereochemical conformation over a 100 ns time frame. Our findings suggest that these alkaloids from Withania somnifera hold promise as effective treatments against tumor growth. Further investigation and exploration are necessary to confirm their efficacy in clinical settings.

Intracellular bactericidal activity and action mechanism of MDP1 antimicrobial peptide against VRSA and MRSA in human endothelial cells.

Staphylococcus aureus is a prominent cause of postoperative infections, often persisting within host cells, leading to chronic infections. Conventional antibiotics struggle to eliminate intracellular S. aureus due to poor cell penetration. Antimicrobial peptides are a new hope for tackling intracellular bacteria. Accordingly, this study examines the antimicrobial peptide MDP1, derived from melittin, for its efficacy against intracellular S. aureus. In this study, the physiochemical properties (Prediction of three-dimensional structure, circular dichroism and helical wheel projection analysis) were investigated. Extracellular antibacterial activity and cytotoxicity of MDP1 were also assessed. The mechanism of interaction of MDP1 with S. aureus was evaluated by molecular dynamic simulation, atomic force and confocal microscopy. Bacterial internalization into an endothelial cell model was confirmed through culture and transmission electron microscopy. The effect of the peptide on intracellular bacteria was investigated by culture and epi-fluorescence microscopy. 3D structural prediction proved the conformation of MDP1 as an α-helix peptide. Helical-wheel projection analysis indicated the proper orientation of hydrophobic amino acid residues for membrane interaction. CD spectroscopy of MDP1 showed that MDP1 in SDS 10 and 30 mM adopted 87 and 91% helical conformation. Atomic force and confocal microscopy assessments as well as molecular dynamics studies revealed the peptide-bacterial membrane interaction. MDP1, at the concentration of 0.32 μg mL-1, demonstrated a fold reduction of 21.7 ± 1.8, 1.7 ± 0.2, and 7.3 ± 0.8 in intracellular bacterial load for ATCC, VRSA, and MRSA, respectively. Molecular dynamics results demonstrate a preferential interaction of MDP1 with POPG/POPE membranes, primarily driven by electrostatic forces and hydrogen bonding. In POPC systems, two out of four MDP1 interacted effectively, while all four MDP1 engaged with POPG/POPE membranes. Gathering all data together, MDP1 is efficacious in the reduction of intracellular VRSA and MRSA proved by culture and epi-fluorescent microscopy although further studies should be performed to increase the intracellular activity of MDP1.

Discovery of novel thiazole derivatives containing pyrazole scaffold as PPAR-γ Agonists, α-Glucosidase, α-Amylase and COX-2 inhibitors; Design, synthesis and in silico study

A novel series of thiazole derivatives with pyrazole scaffold 16a-l as hybrid rosiglitazone/celecoxib analogs was designed, synthesized and tested for its PPAR-γ activation, α-glucosidase, α-amylase and COX-2 inhibitory activities. Regarding the anti-diabetic activity, all compounds were assessed in vitro against PPAR-γ activation, α-glucosidase and α-amylase inhibition in addition to in vivo hypoglycemic activity (one day and 15 days studies). Compounds 16b, 16c, 16e and 16 k showed good PPAR-γ activation (activation % ≈ 72–79 %) compared to that of the reference drug rosiglitazone (74 %). In addition, the same derivatives 16b, 16c, 16e and 16 k showed the highest inhibitory activities against α-glucosidase (IC50 = 0.158, 0.314, 0.305, 0.128 μM, respectively) and against α-amylase (IC50 = 32.46, 23.21, 7.74, 35.85 μM, respectively) compared to the reference drug acarbose (IC50 = 0.161 and 31.46 μM for α-glucosidase and α-amylase, respectively). The most active derivatives 16b, 16c, 16e and 16 k also revealed good in vivo hypoglycemic effect comparable to that of rosiglitazone. In addition, compounds 16b and 16c had the best COX-2 selectivity index (S.I. = 18.7, 31.7, respectively) compared to celecoxib (S.I. = 10.3). In vivo anti-inflammatory activity of the target derivatives 16b, 16c, 16e and 16 k supported the results of in vitro screening as the derivatives 16b and 16c (ED50 = 8.2 and 24 mg/kg, respectively) were more potent than celecoxib (ED50 = 30 mg/kg). In silico docking, ADME, toxicity, and molecular dynamic studies were carried out to explain the interactions of the most active anti-diabetic and anti-inflammatory compounds 16b, 16c, 16e and 16 k with the target enzymes in addition to their physiochemical parameters.

Exploring the anticancer potential of new 3-cyanopyridine derivatives bearing N-acylhydrazone motif: Synthesis, DFT calculations, cytotoxic evaluation, molecular modeling, and antioxidant properties.

3-Cyanopyridine derivatives are known for exhibiting excellent anticancer activity due to their strong capability to inhibit various biological targets, including Pim-1 kinase, survivin, and tubulin polymerization. On the other hand, N-acylhydrazones (NAH) are known to be a very versatile motif in medicinal chemistry and drug design. Based on these data, we report in this paper, the synthesis of novel 3-cyanopyridines incorporating N-acyl hydrazine scaffold, the evaluation of their cytotoxicity on the breast (MCF-7) and ovarian (A-2780) cancer cell lines and their antioxidant properties. Excluding 4a and 4d, all tested molecules exhibited high cytotoxicity against A-2780, with IC50 values ranging from 1.14 to 1.76 µM. Conversely, only four molecules 3d, 4b, 4c, and 4d demonstrated cytotoxicity against MCF-7, with IC50 values ranging from 1.14 to 3.38 µM. On the other hand, all the tested molecules exhibited a moderate antioxidant capacity in both the DPPH and metal chelation assays. Docking and molecular dynamics studies revealed that 2d, 3d, and 4d are potential inhibitors of tubulin and the œstrogen receptor, which may explain their high cytotoxicity. These results are promising to study these newly synthesized 3-cyanopyridine-N-acylhydrazones in depth for use as potential anticancer candidates.

Interactions between basal dislocation and [formula omitted] twin boundary in HCP metal: A molecular dynamics study

For hexagonal close-packed (HCP) metals having a c/a<3, basal <a> slip is the most common slip system, and {112̅2} twinning is one of the primary plastic deformation modes when compressive stress is applied along the c-axis. In this work, molecular dynamics simulations have been applied to reveal the interaction mechanism between different basal <a> dislocations and {112̅2} twin boundaries (TBs) in Mg, Zr and α-Ti. When the 000113[112̅0] dislocation interacts with the {112̅2} TB, it is transmuted into a 112̅2-{112̅1} double twin (DT). With increasing shear stress, the growth of the 112̅2-{112̅1} DT is impeded by the other side of the {112̅2} TB, it transmutes into (0001)13<101̅0> dislocations and twin dislocations (TDs). Furthermore, the {112̅1} TB is capable of transforming into a {112̅2} TB and a new co-zone {112̅1} TB, which then forms a twin-twin junction (TTJ) to release stress concentration. When the 000113[21̅1̅0] dislocation interacts with {112̅2} TBs, it transmuted into a I2 SFs in the twin and a TD with one-layer height on the {112̅2} TB. But the 000113[1̅21̅0] dislocation would be impeded by the {112̅2} TB and couldn’t be transmuted further.

The Role of Molecular Dynamics Simulations in Elucidating Interactions between Antimicrobial Peptides and Model Biological Membranes

In addressing the global problem of antimicrobial resistance, an emerging class of molecules called antimicrobial peptides (AMPs) are being widely studied. Their interactions with cell membranes are instrumental in their killing action, usually by forming pores or translocating to act on an internal target. Molecular dynamics (MD) simulations have played an essential role in understanding the atomistic mechanisms of such interactions. This review will highlight key findings from various MD studies, such as the formation of nanoaggregates and different types of pores. We will also discuss the role of selecting the membrane model composition, the level of detail in the simulation, and the choice of force field. It is evident in this review that our understanding of the interactions of AMPs and membranes has grown over the recent years through the help of MD simulations. Still, remaining concerns in MD studies of such systems must be addressed to gain more information.

Evolution of shielding cloud under oscillatory external forcing in strongly coupled ultracold neutral plasma

This paper investigates the dynamics of crystalline clusters observed in Molecular Dynamics (MD) studies conducted earlier (Yadav et al., 2023) for ultra-cold neutral plasmas. An external oscillatory forcing is applied for this purpose, and the evolution is tracked with the help of MD simulations using the open-source LAMMPS software. Interesting observations relating to cluster dynamics are presented. The formation of a pentagonal arrangement of particles is also reported.

Ignition and combustion of AlH3-nanoparticles: A molecular dynamics study

AlH3 has tremendous potential for hydrogen energy storage and energetic applications. The structure and thermodynamic properties of core-shell AHNP with different oxidation degrees from ignition to combustion are studied using ReaxFF molecular dynamics simulations. Two models covered by different alumina shells are built. Results indicate that the thinner shell is ready to form an Al-rich environment, which is crucial for accelerating ignition and subsequent combustion processes. In ignition period, the influence of shell is investigated by comparing surface oxygen adsorption rates, oxidation degree of Al and H atoms, and stress evolution of AHNP. AHNP with thinner shell exhibits a higher O adsorption rate to form an O-rich environment, which accelerates the oxidation process of Al atoms. A thicker shell significantly inhibits the thermal diffusion of core Al and H atoms, while H atoms are still able to penetrate it with a low diffusion rate. Stress analysis shows the thickness of the shell directly affect the thermal diffusion rate of Al atoms. The combustion of AHNP can be divided into three stages: rapid, slow, and self-sustaining combustion. The combustion process is controlled by the particle and external O atoms diffusion behaviors. A detailed structural evolution process during AHNP combustion has also been clarified through the displacement analysis. The findings provide a theoretical foundation for the diffusion-dominated combustion mechanism of AHNP from an atomic view. Novelty and Significance StatementAlH3 has tremendous potential for hydrogen energy storage and energetic applications. At present, the combustion mechanism of AlH3-nanoparticles (AHNP) is still not well understood, and the atomic-scale evolution process and reaction mechanism are also poorly studied, which is difficult to obtain in experiments. In this study, the ignition and combustion mechanisms of AHNP is revealed based on the ReaxFF molecular dynamics simulations, and the influence of oxidation degree on the ignition and combustion of AHNP is also clarified, which can provide theoretical guidance for the application of AHNP as a clean fuel and preparing for the combustion research of AHNP coated with different materials.

Identifying Potent Breast Cancer Inhibitors Against ERα Target Using Pharmacophore Model, 3D‐QSAR and MD Studies

Abstractthe current investigation, 109 known ERα inhibitors have been developed in the current research; pharmacophore modeling, Molecular docking, MM‐GBSA, and MD study have been performed to investigate the binding affinity of 9‐anilinoacridines with heterocyclic substitutes as selective ERα inhibitors for breast carcinoma. Pharmacophore model have been developed by Schrodinger suite 2019–2 phasemodule. To predict binding free energy of the ligands in complex with PDB and post docked energy minimization was performed by Prime, MM‐GB/SA module. The Induced fit docking studies were performed on the ligand modulated dynamic behaviour of the protein molecular dynamics study. A statistical substantial 3D ‐ QSAR design was created using the pharmacophore hypothesis. 109 known ERα inhibitors have been developed with pIC50 values between 4.0 and 6.0 and were used in ligand‐based pharmacophore modelling and 3D‐QSAR analysis. R2 (0.8294), Q2 (0.7~0.8), and F value (83.5) were used to statistically validate the developed five‐point hypothesis DHRRR1 employing a minimum square of four. Molecular dynamics simulations were run to comprehend the conformational changes and ligand stability at the protein active pocket. The predicted 3D‐QSAR model significantly correlated with experimentally reported in‐vitro antitumor activity. These in‐silico discoveries will help in the future search for potent ERα inhibitors with desirable pharmacophoric properties.

In silico advancements in Peptide-MHC interaction: A molecular dynamics study of predicted glypican-3 peptides and HLA-A*11:01

Our study employed molecular dynamics (MD) simulations to assess the binding affinity between short peptides derived from the tumor-associated antigen glypican 3 (GPC3) and the major histocompatibility complex (MHC) molecule HLA-A*11:01 in hepatocellular carcinoma. We aimed to improve the reliability of in silico predictions of peptide-MHC interactions, which are crucial for developing targeted cancer therapies. We used five algorithms to discover four peptides (TTDHLKFSK, VINTTDHLK, KLIMTQVSK, and STIHDSIQY), demonstrating the substantial potential for HLA-A11:01 presentation. The Anchored Peptide-MHC Ensemble Generator (APE-Gen) was used to create the initial structure of the peptide-MHC complex. This was followed by a 200 ns molecular dynamics (MD) simulation using AMBER22, which verified the precise positioning of the peptides in the binding groove of HLA-A*11:01, specifically at the A and F pockets. Notably, the 2nd residue, which serves as a critical anchor within the 2nd pocket, played a pivotal role in stabilising the binding interactions.VINTTDHLK (ΔGSIE = −14.46 ± 0.53 kcal/mol and ΔGMM/GBSA = −30.79 ± 0.49 kcal/mol) and STIHDSIQY (ΔGSIE and ΔGMM/GBSA = −14.55 ± 0.16 and −23.21 ± 2.23 kcal/mol) exhibited the most effective binding potential among the examined peptides, as indicated by both their binding free energies and its binding affinity on the T2 cell line (VINTTDHLK: IC50 = 0.45 nM; STIHDSIQY: IC50 = 0.35 nM). The remarkable concordance between in silico and in vitro binding affinity results was of particular significance, indicating that MD simulation is a potent instrument capable of bolstering confidence in in silico peptide predictions. By employing MD simulation as a method, our study provides a promising avenue for improving the prediction of potential peptide-MHC interactions, thereby facilitating the development of more effective and targeted cancer therapies.

Suppression effect of CO2 on ignition and combustion of AlH3-nanoparticles: A molecular dynamics study

AlH3 is a high-capacity hydrogen storage material but is prone to explosion. Thermodynamic and structural properties of AlH3-nanoparticles at different CO2 inerting systems from ignition to combustion are studied using ReaxFF-MD method. The influence of CO2 on AlH3-nanoparticles ignition and combustion is investigated by comparing the changes of surface O adsorption rates, particle charge, temperature rise rates and so on. Results indicate that an increase in CO2 is crucial for suppressing AlH3-nanoparticles ignition and combustion by impeding the formation of an Al-rich environment. In contrast to three stages of AlH3-nanoparticles combustion in pure O2 system: surface combustion, slow temperature rise, and self-sustaining combustion, the process of CO2 inerting system is different, with third stage is slow temperature rise at a constant rate. When CO2 concentration reaches to 90%, the dehydrogenation rate reduces by 70.0%, the temperature rise rate decreases by 78.6%, and the ignition delay time reaches 45 ps.

Design, synthesis, molecular dynamics studies and biological evaluations of 4-hydroxy-5-pyrrolinone-3-carbohydrazides as HIV-1 integrase inhibitors

Acquired immune deficiency syndrome (AIDS) diseases despite the efficacy of anti-HIV therapy, remain one of the human's most serious problems. Hence, the introduction of novel anti-HIV agents as first-line therapy is still required. HIV integrase lacking human enzyme homologous is an interesting target for developing new anti-HIV drugs. Following our attempts to describe active integrase inhibitor structures, here a series of novel 4-Hydroxy-5-pyrrolinone-3-carbohydrazides as HIV integrase inhibitor agents were identified. Biological results showed that all compounds could inhibit integrase strand transfer reaction and also exhibited anti-HIV activity in a cell-based assay. The interaction between integrase and designed compounds was investigated using molecular docking and molecular dynamics simulations.

Diverse Microstructures and Quasi-Ionic Liquid-like Transport Mechanisms in Concentrated "Water-in-Salt" Lithium Salt Electrolytes: A Molecular Dynamics Study.

"Water-in-salt"(WIS) electrolytes as potential green and nonflammable electrolytes are currently applied in various energy storage devices, such as lithium-ion batteries and supercapacitors. However, the microstructure at molecular scale and fast ion transport mechanism in such aqueous electrolytes are still under heavy debate due to the complex interactions among ions and water. Here, molecular dynamics simulations are used to study the microstructure and ion transport behaviors from the very dilute LiTFSI/water solution to the highly concentrated WIS electrolytes. It revealed that the diverse microstructures such as completely hydrated ions, ion complexes, and bridge-water molecules are jointly responsible for the electrochemical stability of WIS electrolytes. Diffusion model analysis showed that the Li+ ions exhibit a vehicular transport mechanism with first shell water molecules and structural diffusion mechanism with TFSI- anions. The lithium ion and its first hydration shell act as a single cationic entity. The entity forms a quasi-ionic liquid-like dynamic transport structure with associated anions. Our study challenges previous findings that the high transport dynamics of lithium ions arises from their transport in water-rich nanodomains in high-concentration WIS systems.

Exploration of green catalytic Hantzsch process for synthesis of polyhydroquinoline derivatives and their in silico & in vitro evaluation as anti-tubercular agents

Polyhydroquinolines (PHQ) were long known for various pharmacological activities and numerous methods were reported for their synthesis by using different reaction conditions and catalysts. An attempt has been made to synthesize PHQs by following the environmental friendly green chemical approaches by using reusable and recyclable catalyst and solvent materials. Twelve compounds (2A-2L) were synthesized with varied substitutions on the aromatic ring by following the Hantzsch one-pot approach with bleaching earth clay and polyethylene glycol. Use of novel reaction conditions has improved the yield and drastically reduced the time required for the completion of the reaction. The DFT analysis revealed the structural features and the stability of the compound, and later the compounds were subjected to molecular docking against two key proteins of the M. tuberculosis H37 Ra InhA and DprE1. It was found that few of the compounds showed excellent binding interactions compared to the co-crystalized ligand. Later, all the synthesized compounds were subjected to the in vitro antimycobacterial activity using the Kirby-Bauer disk diffusion method, MICs were calculated by REMA assay and the hemolytic assay was performed to check cytotoxicity. Compounds 2K and 2E were found to show better inhibitory activity than the standard rifampin. The antimycobacterial activity of the PHQ compounds might be due to the interaction of the InhA and DprE1, which can be correlated positively and supported by the structural features and the in silico interaction data. Parallelly, molecular dynamic simulation studies were carried out with ligand 2K for the time frame of 100 ns against both targets InhA and DprE1 revealing the formation of stable complexes which further validate the ligand 2K as a potential lead molecule for further studies. The compounds can be further subjected to lead optimization for improved activity.

Drug repositioning for rosacea disease: Biological TARGET identification, molecular docking, pharmacophore mapping, and molecular dynamics analysis

Rosacea is a chronic dermatological condition that currently lacks a clear treatment approach due to an uncomprehensive knowledge of its pathogenesis. The main obstacle lies in understanding its etiology and the mode of action of the different drugs used. This study aims to clarify these aspects by employing drug repositioning. Using an in silico approach, we performed a transcriptomic analysis comparing samples from individuals with diverse types of rosacea to those from healthy controls to identify genes deregulated in this disease. Subsequently, we realized molecular docking and molecular dynamics studies to assess the binding affinity of drugs currently used to treat rosacea and drugs that target proteins interacting with, and thus affecting, proteins deregulated in rosacea. Our findings revealed that the downregulation of SKAP2 and upregulation of S100A7A in rosacea, could be involved in the pathogenesis of the disease. Furthermore, considering the drugs currently used for rosacea management, we demonstrated stable interactions between isotretinoin and BFH772 with SKAP2, and permethrin and PAC-14028 with S100A7A. Similarly, considering drugs targeting SKAP2 and S100A7A interactome proteins, we found that pitavastatin and dasatinib exert stable interactions with SKAP2, and lovastatin and tirbanibulin with S100A7A. In addition, we determine that the types of bonds involved in the interactions were different in SKAP2 from S100A7A. The drug-SKAP2 interactions are hydrogen bonds, whereas the drug-S100A7A interactions are of the hydrophobic type. In conclusion, our study provides evidence for the possible contribution of SKAP2 and S100A7A to rosacea pathology. Furthermore, it provides significant information on the molecular interactions between drugs and these proteins, highlighting the importance of considering structural features and binding interactions in the design of targeted therapies for skin disorders such as rosacea.

A High–Throughput Molecular Dynamics Study for the Modeling of Cryogenic Solid Formation

To predict the favorable thermodynamical conditions and characterize cryogenic pellet formations for applications in nuclear fusion reactors, a high–throughput molecular dynamics study based on a unified framework to simulate the growth process of cryogenic solids (molecular deuterium, neon, argon) under gas pressure have been designed. These elements are used in fusion nuclear plants as fuel materials and to reduce the damage risks for the plasma-facing components in case of a plasma disruption. The unified framework is based on the use of workflows that permit management in HPC facilities, the submission of a massive number of molecular dynamics simulations, and handle huge amounts of data. This simplifies a variety of operations for the user, allowing for significant time savings and efficient organization of the generated data. This approach permits the use of large-scale parallel simulations on supercomputers to reproduce the solid–gas equilibrium curves of cryogenic solids like molecular deuterium, neon, and argon, and to analyze and characterize the reconstructed solid phase in terms of the separation between initial and reconstructed solid slabs, the smoothness of the free surfaces and type of the crystal structure. These properties represent good indicators for the quality of the final materials and provide effective indications regarding the optimal thermodynamical conditions of the growing process.

Benzohydroxamate and nitrobenzohydroxamate affect membrane order: Correlations between spectroscopic and molecular dynamics to approach tuberculosis

This work correlates the effects of benzohydroxamate (BH) and nitrobenzohydroxamate (NBH) anions in two membrane models which may be used for anti-tuberculosis (anti-TB) spectroscopic studies and/or computational studies. Firstly, the BH and NBH influence in the physico-chemical properties of soy asolectin (ASO)-based large multilamellar vesicles (MLVs) were evaluated by spectroscopic and calorimetric studies. In parallel, the BH and NBH interaction with a Mycobacterium tuberculosis (Mtb) inner membrane model, composed of phosphatidyl-myo-inositol-dimannoside (PIM2), was investigated by molecular dynamics (MD) simulations. Spectroscopic data showed a localization of BH close to the lipid phosphate group, while NBH was found close to the choline region. The BH ordered the ASO choline, phosphate and carbonyl regions and disrupted the acyl methylenes, reducing the membrane packing of the lipid hydrophobic region. On the other hand, NBH showed an ordering effect in all the lipid groups (polar, interface and hydrophobic ones). By MD studies, it was found that NBH enhanced the stability of the PIM2 membrane more than BH, while also being positioned closer to its mannosyl oxygens. As in ASO MLVs, BH was localized close to the PIM2 phosphate group and disrupted its acyl chains. However, higher values of lateral diffusion were observed for NBH than BH. Despite this, BH and NBH increased the membrane thickness by 35 %, which suggests a global ordering effect of both drugs. Findings of this work reinforce the accordance and complementarity between MLVs based on ASO and the PIM2 MD model results to study the drug effects in Mtb membrane properties.

Synthesis, Characterization, Antibacterial, and Molecular Docking and Dynamics Studies of Novel 2-thioxoimidazolidin-4-one Analogue

Synthesis, Characterization, Antibacterial, and Molecular Docking and Dynamics Studies of Novel 2-thioxoimidazolidin-4-one Analogue

Molecular dynamics study of the groove-forming mechanism of mechanically scratched grating multilayer aluminum films

For a long time, the forming quality of large area diffraction gratings is restricted by the one-time coating quality and uniformity of large thickness and large area aluminum films. Large thickness coatings, low accuracy of large depth grooves and diamond tool wear problems were the main reasons for the failure of the test to inscribe large area diffraction gratings. Therefore, the use of layered coating process can effectively ensure the uniformity and consistency of large-area and large-thickness grating blanks coated with aluminum film, and improve the high precision of large depth diffraction grating slot type. In order to reveal the mechanism of the groove-forming process of multilayer aluminum films, the microstructure and mechanical properties of different aluminum films were observed. In this article, the removal behavior and mechanism of nanomechanically scratched multilayer aluminum film materials are investigated using a molecular dynamics approach, and the characteristics of multilayer aluminum films scratched into grooves are analyzed in terms of surface morphology, scratching force, structural evolution, dislocation distribution, von Mises stress and shear strain. The results indicate that in the scratching simulation process, multilayer aluminum film has a higher number of removed atoms and a larger atomic displacement compared to single layer aluminum film, which is conducive to precise shape control of the groove. The average tangential force and normal force of multilayer aluminum film show a decreasing trend compared to single layer aluminum film, which helps to scratch grooves and reduce tool wear. The total length of the dislocation lines of the multilayer aluminum film is large, and the distribution area is large, which improves the precision of scratching the grooves. Therefore, an appropriate increase in the number of aluminum film layers has a precise control effect on the groove shape. This study has certain reference significance for analyzing the complex grooving deformation law of grating aluminum film, improving the diffraction efficiency of grating aluminum film, and further improving the manufacturing process of grating aluminum film.

Experimental investigation and molecular dynamics study on the influence of non-ionic fluorocarbon solutions on the fast-wetting mechanism of coal dust

To explore methods for enhancing the wetting performance of coal dust to mitigate its hazards, this study selected four different structures of non-ionic fluorocarbon solutions: perfluorinated propyl acrylate (PFPA), perfluorooctyl acrylate (PFTA), perfluorooctyl sulfonyl phenyloxy ethyl methylacrylate (PPM), and perfluoro propanoic acid (PFA). The dynamic wetting performance and mechanisms of these solutions on coal dust were measured and analyzed through kinetic calculations. The results indicate that all four fluorocarbon solutions achieve optimal wetting performance at a concentration of 0.3 %. Comprehensive analysis shows that their wetting ability follows the order PFPA > PFTA > PPM > PFA. Further analysis reveals that coal dust treated with PFPA shows an increase in structures such as COOH and CO. The relative concentration distribution indicates partial overlap between the fluorocarbon solution and water, with an overlap range of 8.2 Å. Additionally, the maximum diffusion coefficient is 0.577 Å/ps, and the system’s adsorption energy is the highest at −5757.25 kcal/mol.