A Mini Review on Discovery and Synthesis of Remdesivir as an Effective and Promising Drug against COVID-19.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) as a new human coronavirus has begun spreading over Wuhan City/China in December 2019, and then spread rapidly worldwide, causing pneumonia called COVID-19. Up to now, the scientists have extensively attempted to find effective vaccines and drugs for treatment of coronavirus infections. To this end, various pharmaceutical agents are undergoing the clinical studies to assess their potency and efficacy against COVID-19. Based on the new findings, the U.S. food and drug administration (FDA) has issued an emergency use authorization for remdesivir as an effective anti-viral for remedying the hospitalized COVID-19 patients. Recently, the European medicines agency has authorized the use of remdesivir for the treatment of COVID-19. Remdesivir as a nucleotide prodrug exhibits broad-spectrum antiviral activities against RNA viruses. In this short review, we have rendered a brief overview of discovery and synthesis for remdesivir.

Visualizing the influence of point defects on the electronic band structure of graphene.

The supercell approach enables us to treat the electronic structure of defective crystals, but the calculated energy bands are too complicated to understand or compare with angle-resolved photoemission spectra because of inevitable zone folding. We discuss how to visualize supercell band structures more effectively by incorporating unfolded spectral weights and orbital decompositions into them. We then apply these ideas to gain a better understanding of the band structure of graphene containing various types of point defects, including nitrogen impurity, hydrogen adsorbate, vacancy defects and the Stone-Wales defect.

Thioacetamide-induced acute hepatic encephalopathy in rat: behavioral, biochemical and histological changes.

BACKGROUND: As a serious neuropsychiatric disease, hepatic encephalopathy (HE) is a clinical condition with several types regarding chronicity and clinical diversity that can develop as a complication of both acute and chronic liver failure. This study evaluates changes in thioacetamide (TAA)-induced acute hepatic encephalopathy (AHE) in rat as an animal model. METHODS: Both genders of C57BL6, BALB/C mice and Sprague Dawley rats; (10 animals in each group) were compared for induction of AHE to clarify which animal and gender were appropriate. The animals (10 male rats in each group) were categorized in 4 groups according to the dose of the TAA administered (200, 300 and 400 mg/kg of TAA at 24 h intervals for 4 days). A control group was treated with solvent of TAA which was water (5 ml/kg/day). The behavioral, biochemical markers of hepatic failure and histological aspects of thioacetamide (TAA) induced AHE and the correlation between the clinical severity and liver failure biomarkers were evaluated. RESULTS: Rat was shown to be an animal model of choice for AHE while the optimum dosage of TAA to induce AHE was 300 mg/kg/day at 24 h intervals for 4 days. The behavioral score was partially correlated with the rising of some biomarkers and pathological findings. CONCLUSION: Rat can be introduced as the animal of choice for AHE to study the pathophysiology, pharmacology and the survival rate of disease in liver transplant patients.

Tunable band gap in hydrogenated quasi-free-standing graphene.

We show by angle-resolved photoemission spectroscopy that a tunable gap in quasi-free-standing monolayer graphene on Au can be induced by hydrogenation. The size of the gap can be controlled via hydrogen loading and reaches approximately 1.0 eV for a hydrogen coverage of 8%. The local rehybridization from sp(2) to sp(3) in the chemical bonding is observed by X-ray photoelectron spectroscopy and X-ray absorption and allows for a determination of the amount of chemisorbed hydrogen. The hydrogen induced gap formation is completely reversible by annealing without damaging the graphene. Calculations of the hydrogen loading dependent core level binding energies and the spectral function of graphene are in excellent agreement with photoemission experiments. Hydrogenation of graphene gives access to tunable electronic and optical properties and thereby provides a model system to study hydrogen storage in carbon materials.