Experimental Molecular Dynamics Research Articles

Anti-Alzheimer chemical constituents of Morus macroura Miq.: chemical profiling, in silico and in vitro investigations.

Herein, we investigated both fruits and leaves of Morus macroura Miq. as a potential source of bioactive compounds against Alzheimer's disease (AD). LC-HRMS-assisted chemical profiling of its extracts showed that they are a rich source of diverse phytochemicals. Among the 29 identified compounds in both the fruit and leaf extracts, moracin D, chrysin, resveratrol, and ferulic acid were predicted to pass the human blood-brain barrier (BBB), and hence, reach their therapeutic targets in the brain. Subsequently, these compounds were subjected to a comprehensive pharmacophore-based screening for their protein targets relevant to AD using two independent software programs (i.e. Swiss Target Prediction and PharmMapper). The results of this initial virtual screening were further refined by a number of docking and molecular dynamic simulation experiments to suggest a number of crucial AD-related proteins (e.g. acetylcholine esterase, β-secretase, and monoamine oxidase) as potential targets for these compounds. Finally, in vitro testing was performed to validate the in silico investigation's results, where chrysin, resveratrol, and ferulic acid were found to inhibit the predicted AD-related enzymes with IC50 values comparable with those of the reference inhibitors. Additionally, they were able to inhibit the aggregation of amyloid-beta, one of the hallmarks in AD pathogenesis, and to exhibit considerable antioxidant capacity. Our results highlighted Morus macroura compounds as future anti-Alzheimer chemical leads.

In silico Studies Predict Efficient Binding of Remdesivir and Favipiravir with 3-chymotrypsin like protease of SARS-CoV-2 for COVID-19 Interventional Therapy

Favipiravir and remdesivir are investigational drugs for coronavirus disease 2019 that is caused by severe acute respiratory syndrome coronavirus 2. The active forms of these drugs are reported to target and inhibit viral RNA dependent RNA polymerase, which is derived from 3-chymotrypsin like protease, a viral replicase enzyme. The present in silico study explores the comparative efficacy of these drugs to inhibit 3-chymotrypsin like protease and RNA dependent RNA polymerase, to plan therapeutic options for patients based on their disease severity. Active favipiravir and remdesivir molecules bind to 3-chymotrypsin like protease with energies of 6.18 and -6.52 kcal/mol in contrast to -5.62 and -3.91 kcal/mol for RNA dependent RNA polymerase. Further, hydrophobic interactions and salt bridge formations cement drug bindings with 3-chymotrypsin like protease, but not with RNA dependent RNA polymerase. Molecular dynamic simulation experiments, performed under certain experimental constraints reveal that the root mean square flexibilities of active residues in drug complexes with 3-chymotrypsin like protease are lower than in free 3-chymotrypsin like protease making the former more stable than the latter because of their rigidity and stabilities. Both drugs may hence serve as good therapeutic options for early stages of coronavirus disease 2019. However, more severe symptoms may be treated better with favipiravir due to its better binding with RNA dependent RNA polymerase, as compared to remdesivir. The “one drug does not fit all” concept is true for coronavirus disease 2019 as it is being currently realized by clinicians all around the world. Hence precise knowledge about critical interactions of these drugs with the viral enzymes will help medicos make vital therapeutic decisions on interventional options for patients who report to hospitals without over symptoms or with varying degrees of disease severity.

APPLICATION OF ATHERMAL RECOMBINATION CORRECTED DPA MODEL IN NUCLEAR DATA PROCESSING CODE NECP-ATLAS

The Displacement per Atom (DPA) is an important factor used to quantify the irradiation damage of materials. The radiation damage energy production cross section obtained by nuclear data processing code is an essential nuclear data used to calculate the DPA of materials. Nuclear data processing code, such as NJOY, adopts NRT-DPA model to calculate the radiation damage energy production cross section. However, the NRT-DPA model has several well-known limitation. Especially, the number of radiation defects produced in energetic cascades in metals is only ~1/3 the NRT-DPA model prediction. To improve the precision accuracy of DPA calculation, the state-of-the-art Athermal Recombination Corrected DPA (ARC-DPA) model is adopted in heat production and radiation damage energy production cross section module of nuclear data processing code NECP-Atlas. ARC-DPA model can be obtained by simply multiplying with the new efficiency function. The parameters in the new efficiency function are material constants that can be determined for a given material from Molecular Dynamics (MD) simulations or experiments. The material constants of some materials are obtained by MD simulations firstly in this paper. Numerical results show that the radiation damage cross section produced by nuclear data processing code NECP-Atlas adopting NRT-DPA model can agree well with the NJOY code. What’s more, the results from NECP-Atlas adopting ARC-DPA model can provide more physically realistic descriptions of primary defect and agree well with the results from MD simulation numerically.

In silico study of natural compounds from sesame against COVID-19 by targeting Mpro, PLpro and RdRp.

Natural products and traditional medicine products with known safety profiles are a promising source for the discovery of new drug leads. Natural products as sesame were reported to exhibit potential to protect from COVID-19 disease. In our study, the total methanolic extract of Sesamum indicum L. seeds (sesame) were led to isolation of seven known compounds, five lignan; sesamin 1, sesamolin 2, pinoresinol 3, hydroxymatairesinol 6, spicatolignan 7, together with two simple phenolic compounds; ferulic acid 4 and vanillic acid 5. All isolated compounds were evaluated in silico against three important SARS-CoV-2 protein targets; main protease (Mpro), papain-like protease (PLpro) and RNA-dependent RNA polymerase (RdRp) which possessed crucial role in replication and proliferation of the virus inside the human cell. The results revealed that compound 6 has the high affinity against the three main proteins, specially towards the SARS-CoV-2 Mpro that exceeded the currently used SARS-CoV-2 Mpro inhibitor darunavir as well as, exhibiting a similar binding energy at SARS CoV-2 PLpro when compared with the co-crystallized ligand. This activity continued to include the RdRp as it displayed a comparable docking score with remdesivir. Inferiorly, compounds 1 and 2 showed also similar triple inhibitory effect against the three main proteins while compound 7 exhibited a dual inhibitory effect against SARS CoV-2 PLPro and RdRp. Further molecular dynamic simulation experiments were performed to validate these docking experiments and to calculate their binding free energies (ΔGs). Compounds 1, 2, 3, 6, and 7 showed comparable binding stability inside the active site of each enzyme with ΔG values ranged from −4.9 to −8.8 kcal mol−1. All the compounds were investigated for their ADME and drug likeness properties, which showed acceptable ADME properties and obeying Lipinski's rule of five parameters. It can be concluded that the isolated compounds from sesame lignans could be an alternative source for the development of new natural leads against COVID-19.

Catalysis mechanism of solution loss reaction of metallurgical coke in blast furnace: Experimental and modeling study

Carbon solution loss (SL) reaction significantly affects the performance of metallurgical coke in blast furnace. Unfortunately, the mechanism of SL of coke remains unclear to date. This work investigated the catalytic mechanism of coke SL with both molecular dynamic modeling and experiments using cokes loaded Na2CO3, CaCl2, FeCl3 and H3BO3. The positive catalysis of Na2CO3, CaCl2 and FeCl3 while the counter catalysis of H3BO3 were observed with experiments. Kinetic analysis revealed that the positive catalysts notably reduced while the counter catalyst improved the activation energy of SL reaction of coke. The catalytic mechanisms were further elucidated with the molecular dynamics simulation. The planar nucleophilic semi-quinone structures formed between coke molecule and Na or Fe atoms promoted SL reaction thus showing positive catalysis. On the contrary, the electrophilic B2O3 resulted from the combination of B atoms and CO2 inhibited the SL reaction hence manifesting counter catalysis.

Understanding thermo-oxidative degradation of polyacrylic ester elastomer and its nanocomposites through molecular dynamics simulation and experiments

Acrylic rubber is a special class of synthetic rubber with outstanding hydraulic oils, engine oils and transmission fluids resistant properties. A further improvement in the heat resistance of the elastomer is required in view of the stringent application requirements. This can be achieved by adding suitable nanofillers inside the elastomer matrix to enhance the degradation resistance of polyacrylicester elastomer under thermo-oxidative condition. However, polymer recycling and sustainability require knowledge of degradation behaviour. Reactive molecular dynamics simulations were executed on a polyacrylicester model compound composed of ten monomer units (ACM10) to study its thermal decomposition in the presence of oxygen. With the addition of model silica and graphene oxide, initial as well as final decomposition temperature was improved, while the rate of degradation was reduced for ACM10. The simulation method gave an insight into the degradation pathway of ACM10 by analysing different fragmented products like alkenes, alkyl radicals, and carbon dioxide. Pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) technique was employed to verify the results further. The activation energy of degradation calculated both from the simulation and thermogravimetric analysis were also comparable. This investigation would assist to understand and enhance the heat-resistant properties of different elastomers for industrial applications.

Gelation mechanism and tribological performances of two-component cholesterol-based supramolecular gel lubricant

A novel and simple method for the preparation of two-component gel lubricant and some evaluation of its physicochemical and lubricating properties are reported. The addition of two-component gelator including bis(2-ethylhexyl) sulfosuccinate and cholesterol to white oil can result in self-assembly to form a gel. The gelation mechanism was characterized by the combination of atomistic molecular dynamics simulation and experiment. It not only has excellent thermal stability, but also possesses thermal reversibility, creep recovery and thixotropic properties. Noticeably, the gel can significantly enhance lubricous and AW performances of base oil. Obtained by FIB-TEM, EDS, XPS and QCM characterization, we speculate that the gelator forms an effective adsorption and tribochemical reaction film, so it can protect the contact surface from being worn.

Identification of a New Potential SARS-COV-2 RNA-Dependent RNA Polymerase Inhibitor via Combining Fragment-Based Drug Design, Docking, Molecular Dynamics, and MM-PBSA Calculations.

The world has recently been struck by the SARS-Cov-2 pandemic, a situation that people have never before experienced. Infections are increasing without reaching a peak. The WHO has reported more than 25 million infections and nearly 857,766 confirmed deaths. Safety measures are insufficient and there are still no approved drugs for the COVID-19 disease. Thus, it is an urgent necessity to develop a specific inhibitor for COVID-19. One of the most attractive targets in the virus life cycle is the polymerase enzyme responsible for the replication of the virus genome. Here, we describe our Structure-Based Drug Design (SBDD) protocol for designing of a new potential inhibitor for SARS-COV-2 RNA-dependent RNA Polymerase. Firstly, the crystal structure of the enzyme was retrieved from the protein data bank PDB ID (7bv2). Then, Fragment-Based Drug Design (FBDD) strategy was implemented using Discovery Studio 2016. The five best generated fragments were linked together using suitable carbon linkers to yield compound MAW-22. Thereafter, the strength of the binds between compound MAW-22 and the SARS-COV-2 RNA-dependent RNA Polymerase was predicted by docking strategy using docking software. MAW-22 achieved a high docking score, even more so than the score achieved by Remdesivir, indicating very strong binding between MAW-22 and its target. Finally, three molecular dynamic simulation experiments were performed for 150 ns to validate our concept of design. The three experiments revealed that MAW-22 has a great potentiality to inhibit the SARS-COV-2 RNA-dependent RNA Polymerase compared to Remdesivir. Also, it is thought that this study has proven SBDD to be the most suitable avenue for future drug development for the COVID-19 infection.

Rationally designed N-phenylsulfonylindoles as a tool for the analysis of the non-basic 5-HT6R ligands binding mode

Among all of the monoaminergic receptors, the 5-HT6R has the highest number of non-basic ligands (approximately 5% of compounds stored in 25th version of ChEMBL database have the strongest basic pKa below 5, calculated using the Instant JChem calculator plugin). These compounds, when devoid of a basic nitrogen, exhibit high affinity and remarkable selectivity. Despite a decade of research, no clues have been given for explanation of such an intriguing phenomenon. Here, a series of analogs of four known 5-HT6R ligands, has been rationally designed to approach this issue. For each of the synthesized 42 compounds, a binding affinity for 5-HT6R has been measured, together with a selectivity profile against 5-HT1AR, 5-HT2AR, 5-HT7R and D2R. Performed induced fit docking and molecular dynamics experiments revealed that no particular interaction was responsible for the activity of non-basic compounds. In fact, a plain N-phenylsulfonylindole (1e) was found to possess a moderate (5-HT6R, Ki=159nM) affinity. No other monoaminergic receptor has as simple and selective ligand as this one. Thus, it is stated that it binds to the receptor solely based on its conformation and as such, possesses a minimum amount of features, required for binding. Also, any functional group able to form an additional interaction with the receptor increase the binding affinity, like in the case of two highly active non-basic compounds 3e and 5g (5-HT6R, Ki=65nM and 38nM, respectively).

Effect of Dodecyl Trimethyl Ammonium Bromide on the Migration of Water Molecules in the Pores of Lignite: An Experimental and Molecular Simulation Study.

Molecular dynamics simulations and experiments were used to study the influence of dodecyl trimethyl ammonium bromide (DTAB) on the migration of water molecules in the pores of lignite. To simulate the accuracy, 13C NMR was used to confirm the structure of Shengli lignite. It was found through adsorption experiments that DTAB reduces the specific surface area and pore volume of lignite. Molecular simulations indicate that the lignite and water molecules are primarily connected by hydrogen bonding. DTAB impedes the movement of water molecules in the pores of lignite and the storage space of compressed water molecules. Water molecules are mainly present in the pores of lignite in a posture parallel to the XOY plane, which facilitates the formation of hydrogen-bonding networks. However, this also leads to a decrease in the mobility of water molecules. Experimental and simulation results show that DTAB can enter lignite pores, reducing the water absorption in lignite. This is highly significant for the processing and utilization of lignite.

On the Mechanisms of Coalescence of Nanodroplets and Sintering of Solid Particles

The droplet coalescence theory, which implies the refinement and further development of the Frenkel approach, has, for the first time, been used for predicting the characteristic time of coalescence of nanodroplets. The coalescence times obtained for gold nanodroplets agree, in the order of magnitude, with the results of our molecular-dynamics experiments. In addition, the characteristic times of coalescence have been evaluated theoretically for macroscopic droplets of epoxy resin. The results obtained are in good agreement with Geguzin’s experimental data. It has been concluded that the viscous flows arising in coalescing droplets and the corresponding dissipation of the surface free energy underlie the coalescence mechanism of not only macroscopic, but also nanosized droplets. At the same time, the results of our molecular-dynamics calculations and available experimental data indicate that the sintering of crystalline nanoparticles cannot be explained by the Frenkel mechanism of solid body viscous flow.

Atomic diffusion behavior and diffusion mechanism in Fe–Cu bimetal casting process studied by molecular dynamics simulation and experiment

A molecular dynamics (MD) method with an embedded atomic method (EAM) was proposed to study the atomic diffusion behavior and diffusion mechanism in the Fe–Cu bimetal casting process. The results indicated that the diffusion coefficient of the Cu atoms was larger than that of the Fe atoms at the same temperature, but the Fe atoms predominantly diffused into the Cu side in the process of diffusion bonding. Moreover, the relationship between diffusion distance and temperature was predicted by the established model, and the optimal temperature for interface diffusion bonding of Fe–Cu bimetal ranged from 1473K to 1753 K. The diffusion behavior was mainly due to vacancies, which played a key role in the formation of the Cu cluster, and the accumulation of Cu atoms decreased the system energy. Finally, FeAcknowledgmentsCu bimetal casting was prepared to validate the simulated results of the diffusion behavior and diffusion distance, and the simulated results were consistent with the experimental ones.

Flavonoids as Potential anti-MRSA Agents through Modulation of PBP2a: A Computational and Experimental Study.

Recently, the interest in plant-derived antimicrobial agents has increased. However, there are no sufficient studies dealing with their modes of action. Herein, we investigate an in-house library of common plant-based phenolic compounds for their potential antibacterial effects against the methicillin-resistant Staphylococcus aureus (MRSA), a widespread life-threatening superbug. Flavonoids, which are considered major constituents in the plant kingdom, were found to be a promising class of compounds against MRSA, particularly the non-glycosylated ones. On the other hand, the glycosylated derivatives, along with the flavonolignan silibinin A, were able to restore the inhibitory activity of ampicillin against MRSA. To explore the mode of action of this class, they were subjected to an extensive inverse virtual screening (IVS), which suggested penicillin-binding protein 2a (PBP2a) as a possible target that mediates both the antibacterial and the antibiotic-synergistic effects of this class of compounds. Further molecular docking and molecular dynamic simulation experiments were conducted to support the primary IVS and the in vitro results and to study their binding modes with PBP2a. Our findings shed a light on plant-derived natural products, notably flavonoids, as a promising and readily available source for future adjuvant antimicrobial therapy against resistant strains.

Effect of Surface Force on Nanoconfined Shale-Gas Flow in Slit Channels

Summary A model for gas transport in nanoscale channels in shale-gas reservoirs (SGRs) is proposed using a new effective mean free path (MFP) model, which considers the effects of surface/gas interaction and the geometrical termination of a nanochannel boundary. In addition, the influences of the nanochannel dimension, formation-burial depth, surface type, and gas type on nanoconfined gas flow in slit channels are addressed. The nanoconfined gas-flow behavior is investigated for a wide range of temperature and pressure in this work because of the large prospects of shale gas in deep and ultradeep formations with pressure up to 100 MPa and temperature up to 480 K. The newly developed effective MFP model and the gas-flow-rate model are successfully validated with data from molecular dynamics (MD) simulations and experiments. Results show that the effect of surface force reduces the MFP and gas-flow capacity, which increases with a decreasing pressure, a decreasing channel size, and an increasing temperature; that the nanoconfinement effect has weaker influence on gas-transport capacity as the formation-burial depth increases and greater influence as formation pressure decreases during hydrocarbon production from SGRs; that a surface type affects the gas transport, and the gas-flow capacity in carbon (C) channels (organic channels) is stronger than that in silicon (Si) channels (inorganic channels) with the same size; and that the differences among the transport capacities of nitrogen (N2), argon (Ar), and methane (CH4) are not obvious, while the transport capacities of helium (He) are greatly lower compared with CH4 at both the SGR temperature and the laboratory temperature.

Experimental cum computational investigation on interfacial and mechanical behavior of short glass fiber reinforced dental composites

Achieving strong filler/matrix interactions is essential in the design and manufacturing of composite systems. Molecular dynamics simulation has played a vital role in the investigation of interfacial behavior by predicting the mechanical properties of polymer-based composites. There has been, however, a big gap for clearly establishing a correlation between simulations and experiments because of limitations in size and time scale. Herein, a comparative analysis on the interfacial adhesion behavior of the short glass fiber and dental resin matrix is performed combining the atomistic simulations and single fiber/microdroplet pull-out tests in micro-scale. The interfacial shear strength is measured at the molecular level by applying the scale factor on the glass fiber, and the simulations are compared with the experimental results of the pull-out tests. The enhanced reinforcement effects induced by the surface modification via silane coupling agents grafting on the glass fibers are verified in both studies. Moreover, the mechanical properties and dynamic behavior of the dental composites under the longitudinal and transverse tension loadings are examined with quantifying the free volume changes. The findings of this research provide the optimized design guidelines to precisely predict the mechanical performances of the short fiber reinforced dental composites via molecular dynamics simulations and experiments.

Molecular Characterization and Cytotoxic Activity of McTI, a Novel Cystine-Knot Inhibitor from Momordica charantia.

Medicinal plants are rich source of pharmaceutically active peptides and proteins. Momordica charantia, a traditional medicinal plant commonly known as bitter melon, is a member of a family Cucurbitaceae and has been explored for various human diseases such as diabetes, peptic ulcer, malaria, infectious diseases, and cancer. Yet, to date only a handful of studies are available related to the therapeutic potential of Momordica charantia seed proteins. In present study, a novel trypsin inhibitor McTI was purified by 2D-LC technique from ammonium sulphate precipitated crude seed proteins of Momordica charantia. The crude seed proteins and gel filtration fractions were explored for their cytotoxic response against MDA-MB-231 cells. Later, for deeper understanding, complete amino acid sequence of McTI was established by Edman protein sequencing and 3D structure was predicted by comparative homology modeling using template trypsin inhibitor 3 from spiny bitter cucumber. In silico molecular docking and dynamic simulation experiments were also performed to study the interaction of McTI with bovine trypsin. The results revealed that McTI is a 30 amino acids peptide having a molecular mass of 3388.4 Da and showed sequence similarity with previously reported cystine knot trypsin inhibitors from plant. McTI is a disulfide rich peptide having 6 cysteine residues that can form 3 disulfide bonds (Cys3-Cys20, Cys10-Cys22 and Cys16-Cys28). Six hydrogen bond interactions of McTI with bovine trypsin were observed in molecular docking whereas, additional hydrogen bond interactions were noticed in molecular dynamic simulation studies. In cytotoxicity analysis against MDA-MB-231 cells, crude seed proteins and F12 exhibited a significant dose dependent response with an IC 50 values of 82.10 ± 6.46 µg/ml and 81.13 ± 4.26, respectively. These findings suggest Momordica charantia proteins as a possible anticancer agent. Furthermore, McTI is a valuable addition in the squash inhibitor family.

Nephroprotective effect of Combretum micranthum G. Don in nicotinamide-streptozotocin induced diabetic nephropathy in rats: In-vivo and in-silico experiments

Ethnopharmacological relevanceCombretum micranthum G. Don (CM) is extensively used in traditional medicine throughout West Africa and commonly known as “long-life herbal tea” or “plant to heal”. Further, traditional healers frequently use the title plant to mitigate of renal disorders. Aim of the studyTo explore the nephroprotective property of standardised hydroalcoholic extract of Combretum micranthum in nicotinamide-streptozotocin induced diabetic nephropathy in rats. In addition, in-silico computational experiments were performed with bioactive compounds of the title plant against PPARα and PPARγ. Material and methodsMale rats were made diabetic by a single intraperitoneal (ip) injection of STZ (50 mg/kg), 15 min after ip administration of NA (100 mg/kg) dissolved in normal saline. The diabetic rats received CM extract (200 and 400 mg/kg p.o.) daily, for eight weeks. Body weights and blood glucose (non-fasting and fasting) of rats were measured weekly. Daily food and water consumption were also measured. After 8 weeks of treatment, urine biochemical parameters such as N-Acetyl-β-D-Glucosaminidase (NAG), urea (UR), uric acid (UA), creatinine (CRE), and serum markers of diabetes, kidney damage and liver damage such as insulin, lipid parameters), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (γGT), albumin (Alb), magnesium (Mg2+), calcium (Ca2+), phosphorus (P), were estimated. Blood glycosylated hemoglobin (HbA1C) were also estimated. kidney and liver were used for biochemical estimation of oxidative stress markers such as lipid peroxidation, superoxide dismutase (SOD) activity and glutathione peroxidase (GPx) activity. The kidney and pancreas were used for histopathological study. Further, HPLC chemoprofiling of CM extract and in-silico molecular simulation experiments were performed. ResultsAt the end of eight weeks, renal damage induced by the consequence of prolong diabetic condition was confirmed by altered levels of serum and urine kidney and liver function markers, oxidative stress markers and histopathological variations in kidney. Treatment with CM extract ameliorated the diabetes mellitus-induced renal biochemical parameters and histopathological changes. Further, HPLC-UV & MS experiments revealed that CM extract contains several bioactive compounds including hyperozide (62.35 μg/mg of extract) and quercitrin (19.07 μg/mg of extract). In-silico experiment exhibited cianidanol (−17.133), epicatechin (−15.107) exhibited higher docking score against PPARα and luteoforol (−11.038), epigallocatechin (−10.736) against PPARγ. Based on docking and drug likeness score, four bioactive compounds were selected for molecular dynamic experiments. Cianidanol and epigallocatechin out of the 30 compounds are concluded as a potential candidate for the treatment of DN through activating PPARα and PPARγ target protein. ConclusionsTaken together, the present study provided the scientific footage for the traditional use of Combretum micranthum.

Self-Deicing Electrolyte Hydrogel Surfaces with Pa-level Ice Adhesion and Durable Antifreezing/Antifrost Performance.

Despite the remarkable advances in mitigating ice formation and accretion, however, no engineered anti-icing surfaces today can durably prevent frost formation, droplet freezing, and ice accretion in an economical and ecofriendly way. Herein, sustainable and low-cost electrolyte hydrogel (EH) surfaces are developed by infusing salted water into a hydrogel matrix for avoiding icing. The EH surfaces can both prevent ice/frost formation for an extremely long time and reduce ice adhesion strength to ultralow value (Pa-level) at a tunable temperature window down to −48.4 °C. Furthermore, ice can self-remove from the tilted EH surface within 10 s at −10 °C by self-gravity. As demonstrated by both molecular dynamic simulations and experiments, these extreme performances are attributed to the diffusion of ions to the interface between EH and ice. The sustainable anti-icing properties of EH can be maintained by replenishing in real-time with available ion sources, indicating the promising applications in offshore platforms and ships.

Determining the effect of the non-ionic surfactant AEO9 on lignite adsorption and wetting via molecular dynamics (MD) simulation and experiment comparisons

By combining a molecular dynamics (MD) simulation approach with experimental measurements, this study elucidated the molecular interactions between the fatty alcohol polyoxyethylene ether-9 (AEO9; i.e., a surfactant) and lignite. Moreover, the micro-dynamic process of wetting and adsorption of surfactant molecules onto coal dust molecules were also studied. In the wettability test, the evaporation rate of coal decreased significantly after AEO9 addition. The measured contact angle first decreased and then increased with increased AEO9 concentration. A lower contact angle was indicative of better wetting performance. Using the Materials Studio software, the motion process of the water/AEO9/lignite system was simulated. The resulting structural chart indicated that AEO9 can be adequately adsorbed onto the coal surface. By analyzing the changes in the relative concentration curves along the Z-axis and water mobility before and after AEO9 addition, it was found that AEO9 can enhance the hydrophilicity of lignite. The simulated adsorption isotherms and the calculated interaction energy between molecules suggested simultaneous adsorption onto the lignite surface. X-ray photoelectron spectroscopy (XPS) analysis also revealed that the elemental C content of the surface decreased while the O content increased after coating the lignite surface with AEO9. Given that a great number of oxyethylene groups are present in AEO9, we concluded that AEO9 efficiently adsorbed onto the lignite surface. The present study is of great significance to the enhancement of dust suppressant performance and reducing coal dust hazards.

Stability of a Two-Layer Silicene on a Nickel Substrate upon Intercalation of Graphite

The processes of lithization and delithization of a perfect and defective (containing monovacancies) silicene channel located on an Ni(111) substrate are studied in a molecular-dynamic (MD) experiment. It is shown that such a system can exist up to 1 ns in time without destruction. The limiting amount of lithium ions intercalated into the silicene channel modified by monovacancies is 20% higher than for a defect-free structure. At the same time, the silicene sheets are not destroyed and retain their integrity. The predominant observed arrangement of lithium atoms in the channel is above the centers of the hexagonal silicon rings. In the channel formed by perfect silicene, the lithium mobility coefficient is twice as high as in a defective structure. In general, nickel as a substrate for a silicene channel can be a promising material in terms of achieving high dynamic capacity of a silicene electrode for lithium-ion batteries.