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The management of SARS-CoV-2 has not yet been clearly determined and is based on potential therapies evaluated during the SARS-CoV and MERS-CoV outbreaks. An emerging potential therapeutic approach currently being evaluated in numerous clinical trials is the remdesivir agent, which acts on COVID-19 by interfering with key steps in the virus replication cycle. It is considered a therapeutic option to be evaluated against COVID-19, based on data on its in vitro and in vivo activity against MERS-CoV and SARS-CoV coronaviruses. In this work, we provide an overview of remdesivir's discovery, mechanism of action, and the current studies exploring its clinical effectiveness. Recommendations for its use against COVID-19 infection are also summarized. [ABSTRACT FROM AUTHOR]

Synthesis of apatites, Na 1− x K x CaPb 3 (PO 4 ) 3 0 ⩽ x ⩽ 1, with anion vacancy were carried out using solid state reactions. The solid solution of apatite-type structure crystallize in the hexagonal system, space group P6 3 /m (No. 176). Rietveld refinements showed that around 90% of Pb 2+ cations are located in the (6 h ) sites, the left amount of Pb 2+ cations are located in the (4 f ) sites; 27–31% of Ca 2+ cations are located in the (6 h ) sites, the left amount of Ca 2+ cations are located in the (4 f ) sites. The ninefold coordination sites (4 f ) are also occupied by the K + and Na + monovalent ions. The structure can be described as built up from [PO 4 ] 3− tetrahedra and Pb 2+ /Ca 2+ of sixfold coordination cavities (6 h positions), which delimit void hexagonal tunnels running along [0 0 1]. These tunnels are connected by cations of mixed sites (4 f ) which are half occupied by Pb 2+ /Ca 2+ and half by Na + /K + mixed cations. The assignment of the observed frequencies in the Raman and infrared spectra is discussed on the basis of a unit cell group analysis and by comparison with other apatites. Vibrational spectra of all the compositions are similar and show some linear shifts of the frequencies as a function of the composition toward lower values due the substitutions of Na + by K + with a larger radius. [ABSTRACT FROM AUTHOR]

Emerging viruses are a major public health problem. Most zoonotic pathogens originate in wildlife, including human immunodeficiency virus (HIV), influenza, Ebola, and coronavirus. Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus called SARS-associated coronavirus (SARS-CoV). Viruses are charged colloidal particles that have the ability to adsorb on surfaces depending on pH. Their sorptive interaction with solid particles has important implications for their behavior in aquatic environments, soils, sewage sludge, and other solid materials and their removal or concentration by water treatment processes. Current state of knowledge on the potential of wastewater surveillance to understand the COVID-19 pandemic is reviewed. This study also identified wastewater irrigation systems with a higher risk of COVID-19 transmission. Emphasis was placed on methodologies for the detection and quantification of SARS-CoV-2 in wastewater. Unlabelled Image • Evidence for the presence of COVID-19 in wastewater • Detection methods and prevalence of viruses in wastewater • Knowledge needs for public health. • Recommendations on research and investigation priorities [ABSTRACT FROM AUTHOR]

This paper reports on the fabrication of material comprised of chitosan stabilized silver nanoparticles on the carbon paste and its electro-catalytic reduction toward 4-nitroaniline. The synthesized material was obtained when AgNO 3 was mixed with chitosan as a stabilizing agent and NaBH 4 as a reducing agent. The developed Chitosan-AgNPs has been confirmed using UV–Vis spectroscopy, X-Ray diffraction analysis, scanning electron microscopy (SEM) and infrared spectroscopy. The synthesized chitosan-Ag NPs exhibit particle size around 51 nm. To build a voltammetric sensor (Chitosan-Ag NPs/CPE), a carbon paste electrode has immersed in the liquid suspension of chitosan-Ag NPs, thus, it could be employed for electro-catalytic reduction of 4-NA in 0.1 M Britton-Robinson buffer solution (B-R, pH 2). Therefore, the reduction over-potential of 4-NA shifted from −752.26 mV at CPE to −304 mV at chitosan-Ag NPs/CPE, and then showing a surface controlled process with the catalytic rate constant (Kcat) of 0.125 × 10−3 M−1 s−1 and a coefficient of diffusion (D) of 2.20 × 10−6 cm2 s−1 with an enhanced current response. Under optimized conditions, the electro-catalytic reduction peak current of 4-NA increased linearly with increasing of 4-NA concentration over the range of 1 μM to 0.5 mM (R2 = 0.9866) with a detection limit of 0.86 μM (3 × Sb/P). • CS@Ag/CPE has excellent electrocatalytic activity toward p-NA reduction. • The catalytic effect was studied using cyclic voltammetry and chronoamperometry. • All parameters affecting the detection of p-nitroaniline were optimized. • The results indicated the efficiency of proposed electrode to determine p-NA using DPV. [ABSTRACT FROM AUTHOR]

A sensitive, selective and reproducible electrochemical method has been established for the electroanalysis of 4-nitroaniline (4-NA) using a carbon paste electrode modified with a chitosan solution gelled in acetic acid (CS@CPE). The modified electrode was then characterized spectroscopically using Fourier Transform Infrared (FTIR) spectroscopy. In addition, the electrochemical and interfacial characteristics of the as-prepared modified electrode were assessed by potentiodynamic cyclic voltammetry (CV) and AC electrochemical impedance spectroscopy (EIS). Differential pulse voltammetry (DPV) was additionally used to deduce the trace amounts of (4-NA) in phosphate buffered saline (PBS) of pH 7.0 as an ideal electrolyte. Under optimized conditions, the peak current of 4-NA increased linearly with the increasing 4-NA concentration over the range of 0.1 μM to 0.1 Mm. The calibration curve presents two linear ranges of current versus 4-NA concentration with a detection limit of 93.4 nM (3sb / B). The repeatability of the current peak registered at CS@CPE was performed at a level of 0.5 μM 4-NA employing one sensor on the same day for eight measurements. The relative standard deviation was 3.5%. Unlabelled Image • CS@CPE was used to detect 4-nitroaniline by differential pulse voltammetry. • All experimental parameters that affected 4-NA detection were optimized. • The results indicated the feasibility to determine 4-NA in wastewater. [ABSTRACT FROM AUTHOR]

The electrochemical oxidation of ibuprofen was investigated at a montmorillonite-doped carbon paste electrode (Mt–CPE). A well-defined oxidation peak was observed at around 1.02 V/AgCl in phosphate buffer (pH 8). The experimental condition was optimized by varying chemical and electrochemical parameters. The oxidation peak current is linear to the ibuprofen concentration in the ranges 1.0 × 10 − 3 –1.0 × 10 − 6 mol L − 1 and 1.0 × 10 − 6 − 1.0 × 10 − 7 mol L − 1 with a detection limit of 6.80 × 10 − 8 mol L − 1 . The precision (n = 8) assessed as relative standard deviation (R.S.D.) were 1.24% for 1.0 × 10 − 6 mol L − 1 and 1.07% for 4.0 × 10 − 5 mol L − 1 respectively. Possible interferences were tested and evaluated in 1.0 × 10 − 5 mol L − 1 ibuprofen in the presences of common organic and inorganic interfering agents. Based on its high sensitivity and good selectivity, the Mt–CPE was successfully applied to determine ibuprofen in river water and commercial tablets. The satisfactory obtained results confirm the applicability of this sensor in practical analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of graphene by some top-down and bottom-up approaches. • Fabrication mechanism discussion for graphene and its oxide. • Various synthesis methods of different electrodes-based graphene and its derivatives for some pesticides detection. • The principal pesticide categories analysis was addressed. • Future perspectives of graphene-based applications. The unmatched electrochemical properties of graphene have incited the creative mind of electrochemists everywhere in the world. The integration of a suitable sensitive sensor if possible, with a compacted system that could enable displaying real-time data in a portable device and/or reporting it remotely for post analysis, which is essential for long-term control. In this review, we provide an overview of the methods devoted to the fabrication of graphene along with the electrochemical detection of some pesticides with graphene-related materials. Herein, we scrutinize the synthesis procedures frequently adopted for graphene and its derivatives, and how the material properties could be influenced along with the responsible mechanisms of each technic. Some pesticides can act on a broad spectrum of crop-damaging pests, insects and herbs, generally harmful at low levels, the discreet monitoring is vital for improved food quality and mandatory in the industry of food essentially in the agriculture sector, some examples of pesticides molecules are discussed, as the behavior of graphene toward their reduction/oxidation. [ABSTRACT FROM AUTHOR]

In the last few decades, pharmaceuticals, credited with saving millions of lives, have emerged as a new class of environmental contaminants. These compounds can have both chronic and acute harmful effects on aquatic ecosystems and consequently on human health. Therefore, there is an urgent need for the development of extremely sensitive, portable, and low-cost devices to perform analysis. In the present review article, recent reports on the application of various voltammetric and photo-electrochemical techniques using different electrode materials for the determination of antibiotic Ciprofloxacin (CIPRO) are reported. This review provides an insight into direct and indirect electrochemical approaches as well as the photoelectrochemical methods used for the determination of CIPRO. Emphasis is put on the applications of unmodified and modified carbon-based electrodes considering the modifier, supporting electrolytes, analytical method, concentration range, limit of detection, and real matrices. Carbon-based electrodes are the most used materials attributed to their commercial availability, reduced cost, high chemical stability, and non-toxicity. [Display omitted] • Antibiotics have emerged as a new class of environmental contaminants. • Recent carbon-based electrodes with their performances are summarized. • Electrochemical application for each modified/unmodified electrode is briefly discussed. • Direct and indirect approaches for Ciprofloxacin monitoring are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • ODZ and MTZ antibiotics are effective in the treatment of infections in humans and animals. • Electrochemical detection of MTZ/ODZ in various environmental samples. • Future recommendations for quantitative analysis of ODZ/MTZ have been require. Metronidazole (MTZ) and ornidazole (ODZ) are antibiotics veterinary pharmaceuticals that are primarily used to treat and prevent various bacterial and protozoal illnesses in poultry and pigs. They were also utilized as feed additives to promote growth and increase feed efficiency. However, because of their possible detrimental impacts on human health, they have been banned in many countries from usage in animal food production. As a result, sensitive and dependable analytical techniques for monitoring the residues of these chemicals in comestible animal tissues, food, environmental sample...etc are required. Many analytical techniques for determining antibiotics MTZ/ODZ have been described till now. In recent decades, electrochemical techniques with high sensitivity, quick response, ease of handling, and low cost have been frequently used to detect antibiotic residues. This study compiles recent studies on the uses of modified electrodes, taking into account the substrate electrode, modifier, analytical technique, supporting electrolyte, linear dynamic range, and limit of detection, which may be useful to researchers interested in working in this area. [ABSTRACT FROM AUTHOR]

[Display omitted] • Detection/quantification of 4-HNB in contaminated environments are presented. • Redox pathway and reaction mechanism of 4-HNB are described. • Electrochemical application for each modified electrode is briefly discussed. • Recent electrodes with their performances reported for 4-HNB are summarized. Environmental pollution has become a global concern due to indiscriminate use of chemicals to increase crop productivity and also due to rapid industrialization which largely results in the earth's atmosphere being contaminated with undesirable recalcitrant chemicals and xenobiotics compounds. 4-hydroxy-nitrobenzene (4-HNB) is listed as a priority pollutant by the U.S. Environmental Protection Agency. The compound is a major carcinogen in its own right and tends to persist in water and soil. This has prompted researchers to develop a wide range of analytical tools for its determination and assessment. This review intends to provide an overview of recent advances in the application of various voltammetric techniques using different electrode materials for the electrochemical determination of 4-HNB. Among techniques used to detect 4-HNB at low concentrations, some chromatographic techniques are also reviewed. The toxicity and harmful effects caused by the abundance of nitrophenol compounds are highlighted. Researchers with the interest to use electrochemical techniques for determination of electroactive analytes like nitrophenol compounds will benefit from this review how modified electrodes can increase method selectivity and sensitivity. [ABSTRACT FROM AUTHOR]