ISOLATION AND CHARACTERIZATION OF N-HEPTACOSANYL OLEATE FROM THE WHOLE AERIAL PARTS OF CENTELLA ASIATICA LINN.

ABSTRACTVarious studies have already been performed involving the whole aerial parts of Centella asiatica (L.) (Umbelliferae), commonly known as gotu kola orjalbrahmi, and thus, the present investigation has been carried out for the phytochemical study of an ethanolic extract of the aerial parts of C. asiatica.To perform this activity, the drug (1.5 kg) was exhaustively extracted in 95% ethanol using Soxhlet apparatus. The column chromatography wasperformed then for isolating the various phytoconstituents using the solvents of increasing polarity from petroleum ether to methanol. The isolatedcompounds were structurally elucidated using various spectral data analysis, i.e. infrared,1H nuclear magnetic resonance (NMR),13C NMR, and positiveion fast atom bombardment mass spectrometry. One of the isolated compounds was characterized as n-heptacosanyl oleate.Keywords: Whole aerial parts, Centella asiatica, Soxhlet, Column, Heptacosanyl oleate

Hydrogen induced resistance and optical transmittance of pulsed laser deposited Pd/Mg thin films

The hydrogen detection is an important issue for the societal acceptance of H2 as energy carrier. In present research work, we have investigated hydrogen sensing and optical properties of Pd/Mg thin films on glass substrate deposited by pulsed laser (PL). As-deposited thin films have been exposed (hydrogenation) to H2 gas (2 bar) at room temperature in a hydrogenation unit. Hydrogenated and dehydrogenated (at different temperatures) samples have been characterized using X-ray diffractometer (XRD), field-emission scanning electron microscopy (FE-SEM), UV-Vis-NIR spectrophotometer, atomic force microscopy (AFM). XRD results confirm the formation of hydride (MgH2) tetragonal phase upon hydrogenation of Pd/Mg films. Hydrogen induced resistance response of Pd/Mg films has been measured in-situ during hydrogenation/dehydrogenation process by using two- probe electrical method. The response time (sensitivity) of Pd/Mg films for hydrogen gas is ~ 60 s at room temperature. The study of optical transmittance of hydrogenated Pd/Mg films indicates their switchable mirror behavior

Electrochemical sensing of hydrogen peroxide based on nano γ-Fe2O3 modified glassy carbon electrode

162-166Maghemite (γ-Fe2O3) nanoparticles were prepared using chemical synthesis method and used for sensing the hydrogen peroxide. The morphology of the γ-Fe2O3 nanoparticles was characterized by scanning electron microscopy. The γ-Fe2O3 nanoparticles were used to modify glassy carbon electrode (GCE) to form nano γ-Fe2O3 modified GC electrode for electrochemical sensing of hydrogen peroxide (H2O2). A potential controlled cyclic voltammetric (CV) technique was performed to sense hydrogen peroxide using nano γ-Fe2O3 modified GC electrode. The nano γ-Fe2O3 modified GC electrode showed excellent electrocatalytic ability towards H2O2 in 0.1M KCl supporting electrolyte. A significant enhancement in anodic peak current was observed for the nano γ-Fe2O3 modified GC electrode than those of bare electrode. The electrochemical characteristics of hydrogen peroxide on nano γ-Fe2O3 modified GC electrode  had been explored in this research communication

Electrochemical sensing of hydrogen peroxide based on nano γ-Fe2O3 modified glassy carbon electrode

Maghemite (γ-Fe2O3) nanoparticles were prepared using chemical synthesis method and used for sensing the hydrogen peroxide. The morphology of the γ-Fe2O3 nanoparticles was characterized by scanning electron microscopy. The γ-Fe2O3 nanoparticles were used to modify glassy carbon electrode (GCE) to form nano γ-Fe2O3 modified GC electrode for electrochemical sensing of hydrogen peroxide (H2O2). A potential controlled cyclic voltammetric (CV) technique was performed to sense hydrogen peroxide using nano γ-Fe2O3 modified GC electrode. The nano γ-Fe2O3 modified GC electrode showed excellent electrocatalytic ability towards H2O2 in 0.1M KCl supporting electrolyte. A significant enhancement in anodic peak current was observed for the nano γ-Fe2O3 modified GC electrode than those of bare electrode. The electrochemical characteristics of hydrogen peroxide on nano γ-Fe2O3 modified GC electrode  had been explored in this research communication

THE FIRST REPORT OF A POSSIBLE SARS-CoV-2 REINFECTION IN NEPAL

oai:ojs2.jebas.org:article/1Since August 2020, a growing number of confirmed SARS-CoV-2 cases, after approximately three months, in most of them, again presented a new infection episode, which has been defined as reinfection. So far, no cases have been reported in Nepal, and still there is limited the number of them, especially of those fully confirmed. Here, we report a case and discuss its multiple implications in the ongoing COVID-19 pandemic

Carbon-Based Nanomaterials: Promising Antiviral Agents to Combat COVID-19 in the Microbial-Resistant Era

Therapeutic options for the highly pathogenic human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the current pandemic coronavirus disease (COVID-19) are urgently needed. COVID-19 is associated with viral pneumonia and acute respiratory distress syndrome causing significant morbidity and mortality. The proposed treatments for COVID-19 have shown little or no effect in the clinic so far. Additionally, bacterial and fungal pathogens contribute to the SARS-CoV-2-mediated pneumonia disease complex. The antibiotic resistance in pneumonia treatment is increasing at an alarming rate. Therefore, carbon-based nanomaterials (CBNs), such as fullerene, carbon dots, graphene, and their derivatives constitute a promising alternative due to their wide-spectrum antimicrobial activity, biocompatibility, biodegradability, and capacity to induce tissue regeneration. Furthermore, the antimicrobial mode of action is mainly physical (e.g., membrane distortion), characterized by a low risk of antimicrobial resistance. In this Review, we evaluated the literature on the antiviral activity and broad-spectrum antimicrobial properties of CBNs. CBNs had antiviral activity against 13 enveloped positive-sense single-stranded RNA viruses, including SARS-CoV-2. CBNs with low or no toxicity to humans are promising therapeutics against the COVID-19 pneumonia complex with other viruses, bacteria, and fungi, including those that are multidrug-resistant

COVID-19 Vaccines and Thrombosis—Roadblock or Dead-End Street?

Two adenovirus-based vaccines, ChAdOx1 nCoV-19 and Ad26.COV2.S, and two mRNA-based vaccines, BNT162b2 and mRNA.1273, have been approved by the European Medicines Agency (EMA), and are invaluable in preventing and reducing the incidence of coronavirus disease-2019 (COVID-19). Recent reports have pointed to thrombosis with associated thrombocytopenia as an adverse effect occurring at a low frequency in some individuals after vaccination. The causes of such events may be related to SARS-CoV-2 spike protein interactions with different C-type lectin receptors, heparan sulfate proteoglycans (HSPGs) and the CD147 receptor, or to different soluble splice variants of the spike protein, adenovirus vector interactions with the CD46 receptor or platelet factor 4 antibodies. Similar findings have been reported for several viral diseases after vaccine administration. In addition, immunological mechanisms elicited by viral vectors related to cellular delivery could play a relevant role in individuals with certain genetic backgrounds. Although rare, the potential COVID-19 vaccine-induced immune thrombotic thrombocytopenia (VITT) requires immediate validation, especially in risk groups, such as the elderly, chronic smokers, and individuals with pre-existing incidences of thrombocytopenia; and if necessary, a reformulation of existing vaccines

A unique view of SARS-COV-2 through the lens of ORF8 protein

Immune evasion is one of the unique characteristics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) attributed to its ORF8 protein. This protein modulates the adaptive host immunity through down-regulation of MHC-1 (Major Histocompatibility Complex) molecules and innate immune responses by surpassing the host\u27s interferon-mediated antiviral response. To understand the host\u27s immune perspective in reference to the ORF8 protein, a comprehensive study of the ORF8 protein and mutations possessed by it have been performed. Chemical and structural properties of ORF8 proteins from different hosts, such as human, bat, and pangolin, suggest that the ORF8 of SARS-CoV-2 is much closer to ORF8 of Bat RaTG13-CoV than to that of Pangolin-CoV. Eighty-seven mutations across unique variants of ORF8 in SARS-CoV-2 can be grouped into four classes based on their predicted effects (Hussain et al., 2021) [1]. Based on the geo-locations and timescale of sample collection, a possible flow of mutations was built. Furthermore, conclusive flows of amalgamation of mutations were found upon sequence similarity analyses and consideration of the amino acid conservation phylogenies. Therefore, this study seeks to highlight the uniqueness of the rapidly evolving SARS-CoV-2 through the ORF8

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe