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COVID-19 is still widespread worldwide and up to now there is no established antiviral able to control the disease. Main protease is responsible for the viral replication and transcription; thus, its inhibition is a promising route to control virus proliferation. The present study aims to examine detail interactions between main protease and recently reported ninety-seven inhibitors with available X-ray crystallography to define factors enhance inhibition activity; thirty-two of most potent inhibitors were examined to identify sites and types of interaction. The study showed formation of covalent bond, H-bond and hydrophobic interaction with key residues in the active side. Covalent bond is observed in seventeen complexes, all of them by attack of the 145Cys thiol group on Michael acceptor, aldehyde or its hydrate, a-ketoamide, double bond or acetamide methyl group; the latter type requires H-bonding between acetamide carbonyl oxygen and at least one of 143Gly, 144Ser or 145Cys. Potent inhibitors, disulfiram and ebselen docked in the same binding site. Accordingly, factors identify inhibition include forming covalent bond and existing terminal hydrophobic groups and amidic or peptidomimetic structure. Binding affinity was found correlated with topological diameter up to 24 bond, molecular size, branching, polar surface area up to 199 A ˚2 and hydrophilicity.

Disposal of oil‐contaminated wastewater is associated with serious environmental problems since it is drained in seawater or into the ground. These routes of disposal can dangerously affect the lives of both humans and aqua creatures. Therefore, this research study introduces the recovery of petroleum wastewater through the usage of polystyrene‐based adsorbents. High internal phase emulsion polymerization was the used methodology to provide the introduced structures where new approaches have been presented. Unlike the common, the influence of the fabrication parameters of polymeric adsorbents on the oil removal has been investigated. Particularly, different dosing and mixing times were utilized during the preparation stage. Their effect on the polymers surface properties and molecular weights were traced. The obtained adsorbents were subjected to the oil removal stage where optimization of synthesis conditions was taken place. Nearly 92% of the oil content (80 ppm) in the wastewater was removed using the optimized adsorbent. This adsorbent showed surface area of 28.8 m2/g and molecular weight equal 279,970 g/mol. It was acquired by applying 20 min as a dosing time and reaction time of 120 min.

The purpose of this study aims to investigate the surface morphology and roughness of Aluminum induced glass texturing (AIT) substrate after different surface treatments. Aluminum layers were deposited in thickness 370 nm and 240 nm on corning glass sheet using Radio Frequency (RF) power. The effect of different concentrations of hydrofluoric acid (HF), 4%, 5% and 6% on morphology, optical absorption and surface roughness of glass was described. The dipping time of coated glass sheet in HF for 2 min and 5 min created very rough and soft surface, respectively. Optical absorption of AIT substrate after dipping in HF was measured. The optimum texturing process achieved by deposition of aluminum layer 240 nm of thickness and dipping the substrate in 5% HF. The AIT substrate was characterized by low angle X-ray diffraction (XRD), ultraviolet-visible spectrophotometer (UV-VIS), stylus profiler and scanning electron microscope (SEM).