The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is the cause of coronavirus disease 2019 (COVID-19); a severe respiratory distress that has emerged from the city of Wuhan, ...Hubei province, China during December 2019. COVID-19 is currently the major global health problem and the disease has now spread to most countries in the world. COVID-19 has profoundly impacted human health and activities worldwide. Genetic mutation is one of the essential characteristics of viruses. They do so to adapt to their host or to move to another one. Viral genetic mutations have a high potentiality to impact human health as these mutations grant viruses unique unpredicted characteristics. The difficulty in predicting viral genetic mutations is a significant obstacle in the field. Evidence indicates that SARS-CoV-2 has a variety of genetic mutations and genomic diversity with obvious clinical consequences and implications. In this review, we comprehensively summarized and discussed the currently available knowledge regarding SARS-CoV-2 outbreaks with a fundamental focus on the role of the viral proteins and their mutations in viral infection and COVID-19 progression. We also summarized the clinical implications of SARS-CoV-2 variants and how they affect the disease severity and hinder vaccine development. Finally, we provided a massive phylogenetic analysis of the spike gene of 214 SARS-CoV-2 isolates from different geographical regions all over the world and their associated clinical implications.
This study addresses the impacts of metabolites from different microbial taxa on the fabrication and multifunctional biological properties of spherical silver nanoparticles (Ag-NPs). Three microbial ...taxa, a bacterial (Bacillus cereus A1-5), actinomycetes (Streptomyces noursei H1-1), and fungal (Rhizopus stolonifer A6-2) strains were used for Ag-NPs biosynthesis, whereas Streptomyces noursei is demonstrated for the first time. These isolates were identified using either 16S rRNA or ITS gene sequencing. Characterization of Ag-NPs was done using color change analysis, Uv-Vis spectroscopy, FT-IR spectroscopy, XRD, TEM, SEM-EDX, DLS, and Zeta potential analysis. All biosynthesized NPs exhibited spherical shape with different sizes ranged from 6‒50 nm, 6–30 nm and 6–40 nm for NPs obtained by A1-5, H1-1 and A6-2, respectively. The crystalline center cubic face of Ag-NPs was confirmed using XRD at 2θ values 38.08o, 44.27o, 64.41o and 77.36o. FT-IR analysis revealed varied intense absorption peaks for biomolecules required for NPs synthesize by each microbial strain. The stability of spherical Ag-NPs was confirmed due to highly DLS negative surface charge of ‒17.5mV, ‒18.9mV, and ‒15.6mV for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Ag-NPs exhibited a broadspectrum of antibacterial activity against Gram-positive and Gram-negative bacteria with varied effectiveness. They also exhibited a cytotoxic effect against cancer cell line (caco-2) in a dose-dependent pattern with IC50 of 8.9 ± 0.5, 5.6 ± 3.0, 11.2 ± 0.5 μg/ml for NPs synthesized by strains A1-5, H1-1, and A6-2, respectively. Moreover, these spherical Ag-NPs showed larvicidal activity against the 3rd instar larvae of the dengue vector Aedes aegypti.
Materials Science; Nanotechnology; Agriculture; Spherical silver nanoparticles; Ag-NPs biosynthesis; Antibacterial; Antitumor activities; Larvicidal; Aedes aegypti
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•4-Chloro benzaldehyde was coupled with chitosan to prepare Schiff base I.•Benzophenone was coupled with chitosan to prepare Schiff base II.•The chemical structures of the Schiff ...bases verified through FT-IR, TGA and DSC.•The antimicrobial activities of the Schiff bases increased more than chitosan.•The new Schiff bases could be applied as antimicrobial wound dresser.
Recently, there have been significant scientific interests to scientists for the chemical modifications of chitosan to increase its applications. The main objective of this study was to prepare two aromatic chitosan Schiff bases (I and II) via coupling with 4-chloro benzaldehyde and benzophenone respectively for improvement the antimicrobial property of chitosan. The chemical structures of the prepared Schiff bases verified through FT-IR, TGA and DSC. However, degrees of substitution were estimated using potentiometric analysis, and they were 7.9% and 4.17% for Schiff bases (I and II) respectively. Antimicrobial activities evaluation were conducted against three Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Salmonella sp.), two Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Candida albicans strain. The antimicrobial activities of the new derivatives increased significantly more than chitosan in most microorganisms. The minimum inhibitory concentration (MIC) of Schiff base (I) with concentration (50μg/ml) exhibited the highest activity against C. Albicans with growth inhibition up to 27.42%. While, 50μg/ml of Schiff base (II) showed high activity against E. coli, Salmonella sp., S. aeureus and B. cereus more than chitosan. The results clearly suggested that the new Schiff bases could be applied as antimicrobial wound dressing agents to ameliorate wound healing.
Abstract
The present paper evaluates the photocatalytic degradation (
PCD
) performance of the biofabricated hematite nanoparticles (
α-HNPs
) for the degradation approach of the Cefotaxime (
Cfm
). ...The optimum pH of the solution to achieve the best
PCD
was found to be 10.5. The kinetics study for the
PCD
of the
Cfm
via
α-HNPs
has been investigated and the reaction was found to be fellow pseudo-first-order at R
2
= 0.992. The mass loading impact of
α-HNPs
was investigated and estimated for the maximum degradation of
Cfm
0.4 mg/mL. UV–Vis confirmed that
α-HNPs
had a direct transition bandgap at 3.78 eV at a maximum absorption wavelength of 362 nm with suspension stability for 7 days. The probable mechanism of the
Cfm PCD
via
α-HNPs
and the degradation pathway was conducted. The validation of the suspension stability of the
α-HNPs
(−68.6 ± 11.8 mV) was determined using the zeta potential investigation test. XRD investigation was conducted after
Cfm PCD
showing an average crystallite size of 27.0 nm. XRD, TEM, SEM, EDX, and FT-IR analyses have been conducted for the
α-HNPs
before and after
Cfm PCD
confirming the high efficiency for the reusability of the current biocatalyst
α-HNPs
for further use. TEM results of the particle sizes of
α-HNPs
were found at 19.2 ± 4.4 and 20.6 ± 7.4 nm respectively before and after
Cfm PCD
. The efficiency of the
Cfm PCD
was found to be 99.1% after 6 h. High potent as an antibacterial agent of
α-HNPs
was investigated either
α-HNPs
alone or after its
PCD
activity against
Cfm
. The antibacterial activity revealed high sensitivity, especially toward Gram-positive species indicating its promising ability against pathogenic issues. Interestingly,
Cfm@α-HNPs
showed superior anti-proliferative activity as tested by MTT assay and were able to induce apoptosis in MCF7 and HepG2 cell lines using the flow cytometry technique at 20.7% and 17% respectively. Also, The IC
50
of hydrogen peroxide scavenging was estimated and it was manifested that 635.8 and 665.6 μg/mL of
α-HNPs
before and after the
PCD
process of
Cfm
respectively.
Chronic hepatitis B viral (HBV) infection remains a significant global health problem. Evidence‐based guidelines are needed to help providers determine when treatment should be initiated, which ...medication is most appropriate, and when treatment can safely be stopped. The American Association for the Study of Liver Diseases HBV guideline methodology and writing committees developed a protocol a priori for this systematic review. We searched multiple databases for randomized controlled trials and controlled observational studies that enrolled adults ≥18 years old diagnosed with chronic HBV infection who received antiviral therapy. Data extraction was done by pairs of independent reviewers. We included 73 studies, of which 59 (15 randomized controlled trials and 44 observational studies) reported clinical outcomes. Moderate‐quality evidence supported the effectiveness of antiviral therapy in patients with immune active chronic HBV infection in reducing the risk of cirrhosis, decompensated liver disease, and hepatocellular carcinoma. In immune tolerant patients, moderate‐quality evidence supports improved intermediate outcomes with antiviral therapy. Only very low‐quality evidence informed the questions about discontinuing versus continuing antiviral therapy in hepatitis B e antigen‐positive patients who seroconverted from hepatitis B e antigen to hepatitis B e antibody and about the safety of entecavir versus tenofovir. Noncomparative and indirect evidence was available for questions about stopping versus continuing antiviral therapy in hepatitis B e antigen‐negative patients, monotherapy versus adding a second agent in patients with persistent viremia during treatment, and the effectiveness of antivirals in compensated cirrhosis with low‐level viremia. Conclusion: Most of the current literature focuses on the immune active phases of chronic HBV infection; decision‐making in other commonly encountered and challenging clinical settings depends on indirect evidence. (Hepatology 2016;63:284–306)
An efficient power management control for microgrids with energy storage is presented in this paper. The proposed control scheme increases the reliability and resiliency of the microgrid based on ...three distributed energy resources (DERs), namely Photovoltaic (PV), battery, and diesel generator with local active loads. Coordination among the DERs with energy storage is essential for microgrid management. The system model and the control strategy were developed in Real Time Digital Simulator (RTDS). Decoupled d-q current control strategy is proposed and implemented for voltage source converters (VSCs) used to interface the PV and battery sources to the AC grid. A dc-dc buck converter with a maximum power point tracking function is implemented to maximize the intermittent energy generation from the PV array. A controller is proposed and employed for both grid connected and island modes of operation. In grid connected mode, the system frequency and voltage are regulated by the grid. During a fault in island mode, the diesel generator controls the system frequency and voltage in isochronous mode. Results based on the real time digital simulator are provided to verify the superiority and effectiveness of the proposed control scheme.
Channel state estimation (CSE) is essential for orthogonal frequency division multiplexing (OFDM) wireless systems to deal with multipath channel fading. To attain a high data rate with the use of ...OFDM technology, an efficient CSE and accurate signal detection are required. The use of machine learning (ML) to improve channel estimates has attracted a lot of attention lately. This is because ML techniques are more adaptable than traditional model-based estimation techniques. The present study proposes a receiver for low-spectrum usage in OFDM wireless systems on Rayleigh fading channels using deep learning (DL) long short-term memory (LSTM). Before online deployment and data retrieval, the proposed DL LSTM estimator gathers channel state information from transmit/receive pairs using offline training. Based on the simulation results of a comparative study, the proposed estimator outperforms conventional channel estimation approaches like minimum mean square error and least squares in noisy and interfering wireless channels. Furthermore, the proposed estimator outperforms the DL bidirectional LSTM (BiLSTM)-based CSE model. In particular, the proposed CSE performs better than other examined estimators with a reduced number of pilots, no cycle prefixes, and no prior knowledge of channel statistics. Because the proposed estimator relies on a DL neural network approach, it holds promise for OFDM wireless communication systems.
Abstract Metabolites exploration of the ethyl acetate extract of Fusarium solani culture broth that was isolated from Euphorbia tirucalli root afforded five compounds; 4-hydroxybenzaldehyde ( 1 ), ...4-hydroxybenzoic acid ( 2 ), tyrosol ( 3 ), azelaic acid ( 4 ), malic acid ( 5 ), and fusaric acid ( 6 ). Fungal extract as well as its metabolites were evaluated for their anti-inflammatory and anti-hyperpigmentation potential via in vitro cyclooxygenases and tyrosinase inhibition assays, respectively. Azelaic acid ( 4 ) exhibited powerful and selective COX-2 inhibition followed by fusaric acid ( 6 ) with IC 50 values (2.21 ± 0.06 and 4.81 ± 0.14 μM, respectively). As well, azelaic acid ( 4 ) had the most impressive tyrosinase inhibitory effect with IC 50 value of 8.75 ± 0.18 μM compared to kojic acid (IC 50 = 9.27 ± 0.19 μM). Exclusive computational studies of azelaic acid and fusaric acid with COX-2 were in good accord with the in vitro results. Interestingly, this is the first time to investigate and report the potential of compounds 3 – 6 to inhibit cyclooxygenase enzymes. One of the most invasive forms of skin cancer is melanoma, a molecular docking study using a set of enzymes related to melanoma suggested pirin to be therapeutic target for azelaic acid and fusaric acid as a plausible mechanism for their anti-melanoma activity.
The impact of bio-organic amendments on crop production is poorly understood in saline calcareous soils. The aim in the present study was to determine the effects of the application of organic manure ...along with lactic acid bacteria (LAB) on soil quality, and morpho-physio-biochemical responses, seed yield (SY) and essential oil yield (EOY) of fennel plants (Foeniculum vulgare Mill.) grown in saline calcareous soils. Eight treatments of farmyard manure (FM) or poultry manure (PM) individually or combined with Lactobacillus plantarum (Lp) and/or Lactococcus lactis (Ll) were applied to saline calcareous soil in two growing seasons. Either FM or PM combined with LAB had beneficial effects on lowering ECe, pH and bulk density and increasing total porosity, organic matter, and water and nutrient retention capacities in addition to total bacterial population in the soil. Growth, nutrient uptake, SY and EOY of plants were also enhanced when fennel seeds were inoculated with Lp and/or Ll and the soil was amended with any of the organic manures under unfavorable conditions. Compared to control (no bio-organic amendments), FM + Lp + Lt or PM + Lp + Lt treatment signficantlly (P ≤ 0.05) increased plant height by 86.2 or 65.0%, total chlorophyll by 73 or 50%, proline by 35 or 45%, glutathione by 100 or 138%, SY by 625 or 463% and EOY by 300 or 335%, respectively, in fennel plants. Co-application of the naturally occurring microorganisms (i.e., LAB) and organically-derived, nutrient-rich fertilizer (i.e., FM or PM) is recommended to improve yield of fennel plants in saline calcareous soils.
Hemorrhage is the major hindrance over the wound healing, which triggers microbial infections and might provoke traumatic death. Herein, new hemostatic and antibacterial PVA/Kaolin composite sponges ...were crosslinked using a freeze-thawing approach and boosted by penicillin-streptomycin (Pen-Strep). Physicochemical characteristics of developed membranes were analyzed adopting Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), a thermal gravimetric analyzer (TGA), and differential scanning calorimetry (DSC). Furthermore, the impacts of kaolin concentrations on porosity, swelling behavior, gel fraction, and degradation of the membranes were investigated. SEM analyses revealed a spongy-like structure of hydrogels associated with high dispersion of kaolin inside PVA matrix. The thermal characteristics of PVA/Kaolin were significantly ameliorated compared to the prime PVA. Moreover, the results exhibited significant variations of swelling performance, surface roughness and pore capacity due to the alterations of kaolin contents. Besides, the adhesive strength ability was manifestly enhanced for PVA-K0.1 sponge. Biomedical evaluations including antibacterial activity, blood clotting index and thrombogenicity of the membranes were studied. The contact of PVA/Kaolin to blood revealed notable augmentation in blood clotting. Furthermore, the incorporation of kaolin into PVA presented mild diminution in antibacterial activities. Moreover, PVA/Kaolin composites illustrated no cellular toxicity towards fibroblast cells. These remarkable features substantiate that the PVA-K0.1 sponge could be applied as a multifunctional wound dressing.
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