Discovery of Potential Antiviral Compounds against Hendra Virus by Targeting Its Receptor-Binding Protein (G) Using Computational Approaches

Hendra virus (HeV) belongs to the paramyxoviridae family of viruses which is associated with the respiratory distress, neurological illness, and potential fatality of the affected individuals. So far, no competitive approved therapeutic substance is available for HeV. For that reason, the current research work was conducted to propose some novel compounds, by adopting a Computer Aided Drug Discovery approach, which could be used to combat HeV. The G attachment Glycoprotein (Ggp) of HeV was selected to achieve the primary objective of this study, as this protein makes the entry of HeV possible in the host cells. Briefly, a library of 6000 antiviral compounds was screened for potential drug-like properties, followed by the molecular docking of short-listed compounds with the Protein Data Bank (PDB) structure of Ggp. Docked complexes of top two hits, having maximum binding affinities with the active sites of Ggp, were further considered for molecular dynamic simulations of 200 ns to elucidate the results of molecular docking analysis. MD simulations and Molecular Mechanics Energies combined with the Generalized Born and Surface Area (MMGBSA) or Poisson–Boltzmann and Surface Area (MMPBSA) revealed that both docked complexes are stable in nature. Furthermore, the same methodology was used between lead compounds and HeV Ggp in complex with its functional receptor in human, Ephrin-B2. Surprisingly, no major differences were found in the results, which demonstrates that our identified compounds can also perform their action even when the Ggp is attached to the Ephrin-B2 ligand. Therefore, in light of all of these results, we strongly suggest that compounds (S)-5-(benzylcarbamoyl)-1-(2-(4-methyl-2-phenylpiperazin-1-yl)-2-oxoethyl)-6-oxo-3,6-dihydropyridin-1-ium-3-ide and 5-(cyclohexylcarbamoyl)-1-(2-((2-(3-fluorophenyl)-2-methylpropyl)amino)-2-oxoethyl)-6-oxo-3,6-dihydropyridin-1-ium-3-ide could be considered as potential therapeutic agents against HeV; however, further in vitro and in vivo experiments are required to validate this study.

Proposal of a Facile Method to Fabricate a Multi-Dope Multiwall Carbon Nanotube as a Metal-Free Electrocatalyst for the Oxygen Reduction Reaction

In this study, a one-pot, low-temperature synthesis method is considered for the fabrication of heteroatom dope multiwall carbon nanotubes (MWCNT). Doped MWCNT is utilized as an effective electrocatalyst for oxygen reduction reaction (ORR). Single, double, and triple doping of boron, nitrogen and sulfur elements are utilized as the dopants. A reflux system with temperature of 180 °C is implemented in the doping procedure. Actually, unlike the previous studies in which doping on the carbon structures was performed using a furnace at temperatures above 700 °C, in this green and sustainable method, the triple doping on MWCNT is conducted at atmospheric pressure and low temperature. The morphology and structure of the fabricated catalysts were evaluated by Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. According to the results, the nanoparticles were encapsulated in the carbon nanotubes. Aggregated clusters of the sulfur in the case of S-MWCNT are considerable. Cyclic voltammetry (CV), rotating disk electrode, linear sweep voltammetry (LSV), and chronoamperometry electrochemical tests are employed for assessing the oxygen reduction activity of the catalysts. The results illustrate that by using this doping method, the onset potential shifts to positive values towards the oxidized MWCNT. It can be deduced that by doping the N, B, and S atoms on MWCNTs, the defects in the CNT structure, which serve as active sites for ORR application, increase. The N/S/B-doped graphitic layers have a more rapid electron transfer rate at the electrode/electrolyte interface. Thus, this can improve the electrochemistry performance and electron transfer of the MWCNTs. The best performance and electrochemical activity belonged to the NB-MWCNT catalyst (−0.122 V vs. Ag/AgCl). Also, based on the results gained from the Koutecky–Levich (KL) plot, it can be said that the ORR takes place through the 4 e− pathway.

Production of COx-Free Hydrogen and Few-Layer Graphene Nanoplatelets by Catalytic Decomposition of Methane over Ni-Lignin-Derived Nanoparticles

Nickel (Ni)-lignin nanocomposites were synthesized from nickel nitrate and kraft lignin then catalytically graphitized to few-layer graphene-encapsulated nickel nanoparticles (Ni@G). Ni@G nanoparticles were used for catalytic decomposition of methane (CDM) to produce COx-free hydrogen and graphene nanoplatelets. Ni@G showed high catalytic activity for methane decomposition at temperatures of 800 to 900 °C and exhibited long-term stability of 600 min time-on-stream (TOS) without apparent deactivation. The catalytic stability may be attributed to the nickel dispersion in the Ni@G sample. During the CDM reaction process, graphene shells over Ni@G nanoparticles were cracked and peeled off the nickel cores at high temperature. Both the exposed nickel nanoparticles and the cracked graphene shells may participate the CDM reaction, making Ni@G samples highly active for CDM reaction. The vacancy defects and edges in the cracked graphene shells serve as the active sites for methane decomposition. The edges are continuously regenerated by methane molecules through CDM reaction.

Pilot-Scale Studies of WO3/S-Doped g-C3N4 Heterojunction toward Photocatalytic NOx Removal

Due to the rising concentration of toxic nitrogen oxides (NOx) in the air, effective methods of NOx removal have been extensively studied recently. In the present study, the first developed WO3/S-doped g-C3N4 nanocomposite was synthesized using a facile method to remove NOx in air efficiently. The photocatalytic tests performed in a newly designed continuous-flow photoreactor with an LED array and online monitored NO2 and NO system allowed the investigation of photocatalyst layers at the pilot scale. The WO3/S-doped-g-C3N4 nanocomposite, as well as single components, were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller surface area analysis (BET), X-ray fluorescence spectroscopy (XRF), X-ray photoemission spectroscopy method (XPS), UV–vis diffuse reflectance spectroscopy (DR/UV–vis), and photoluminescence spectroscopy with charge carriers’ lifetime measurements. All materials exhibited high efficiency in photocatalytic NO2 conversion, and 100% was reached in less than 5 min of illumination under simulated solar light. The effect of process parameters in the experimental setup together with WO3/S-doped g-C3N4 photocatalysts was studied in detail. Finally, the stability of the composite was tested in five subsequent cycles of photocatalytic degradation. The WO3/S-doped g-C3N4 was stable in time and did not undergo deactivation due to the blocking of active sites on the photocatalyst’s surface.

Synthesis of Ag–decorated vertical graphene nanosheets and their electrocatalytic efficiencies

Herein, we report the successful preparation of Ag–decorated vertical–oriented graphene sheets (Ag/VGs) via helicon wave plasma chemical vapor deposition (HWP–CVD) and radio frequency plasma magnetron sputtering (RF–PMS). VGs were synthesized in a mixture of argon and methane (Ar/CH4) by HWP–CVD, and then the silver nanoparticles on the prepared VGs were modified using the RF-PMS system under different sputtering times and RF power levels. The morphology and structure of the Ag nanoparticles were characterized by scanning electron microscopy (SEM), and the results revealed that Ag nanoparticles were evenly dispersed on the mesoporous wall of the VGs. X-ray diffraction (XRD) results showed that the diameter of the Ag particles increased with the increase of silver loading, and the average size was between 10.49 nm and 25.9 nm, which were consistent with transmission electron microscopy (TEM) results. Ag/VGs were investigated as effective electrocatalysts for use in an alkaline aqueous system. Due to the uniquely ordered and interconnected wall structure of VGs, the area of active sites increased with the Ag loading, which made the Ag/VGs have high oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) performance. The double–layer capacitance (Cdl) of the Ag/VGs under different silver loadings were studied, and the results showed that highest silver content is the best (1.04 mF/cm2). The results showed that, Ag/VGs expected to be a credible electrocatalytic material.