INHIBITIVE ACTION OF IMIDAZOLES FOR COPPER CORROSION IN SULFURIC ACID MEDIUM

The corrosion inhibition of copper in the presence of 10-3 M of imidazole derivatives; Imidazole (IM), 2-Methyle imidazole (MIM), Benzimidazole (BIM) has been investigated in 1.0 M H2SO4 solution using  potentiodynamic  polarization and electrochemical impedance spectroscopy (EIS). Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT) at the B3LYP/6-31+G(d,p) level. Inhibition efficiency of these compounds which has been evaluated via experimental methods was accorded with reported theoretical ones, and following the same order as BIM ˃ MIM ˃ IM

Iron corrosion inhibition by olive mill wastewaters in acid medium

In this paper, the effect of olive mill wastewater (OMW) as corrosion inhibitor for iron in molar hydrochloride solution was investigated by using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. As results, both used techniques gave nearly the same efficiency of inhibition. Polarisation curves indicated that the OMW act as mixed inhibitor without variation of the hydrogen reduction mechanism. The inhibition efficiency increases by increasing OMW concentration to reach a maximum value of 84% at 4ppm. The effect of temperature on the corrosion of iron has also been studied without and with the inhibitor in the range from 298 to 318K. It was found that the rate of corrosion increases with temperature. OMW was adsorbed on the iron surface according to the model of the Langmuir adsorption isotherm. 

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

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A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa.

The progression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Africa has so far been heterogeneous, and the full impact is not yet well understood. In this study, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations predominantly from Europe, which diminished after the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1, and C.1.1. Although distorted by low sampling numbers and blind spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants

www.mdpi.org/ijms/ C- versus O-Arylation of an Enol-Lactone Using Potassium tertbutoxide

Abstract: The use of potassium tert-butoxide as the base in arylation reactions of an enollactone with a series of benzyl halides was explored. Our work demonstrates that the ratio of C-arylation to O-arylation varies with the substitution pattern of the aryl halide

Contamination microbiologique résiduelle des endoscopes digestifs

Les endoscopes sont des dispositifs médicaux qui ne peuvent faire l’objet de mesures de stérilisation en raison de leur caractère complexe et notamment de la sensibilité à la chaleur de certains de leurs constituants. La complexité de leur structure rend possible une accumulation de souillures organiques ou minérales qui peuvent elles-mêmes renfermer des agents infectieux. Une fréquence ou une qualité insuffisante de la procédure de désinfection peut aboutir à la formation d’un biofilm. L’objectif de notre travail est de faire une évaluation de la contamination microbiologique des endoscopes après désinfection dans une unité d’endoscopie du service d’hépato- gastro-entérologie du CHU Hassan II de Fès, Maroc. Les prélèvements ont concerné 13 endoscopes. Ils ont été réalisés en deux phases : l’injection d’une solution de décrochage dans les canaux de l’endoscope, et l’écouvillonnage de l’embout distal, puis insufflation et aspiration. L’eau du rinçage terminal ainsi que la solution de désinfection ont également été contrôlées. Les résultats obtenus ont montré une contamination résiduelle de la flore mésophile aérobie totale (FMAT) de l’ordre de 3,6.103 UFC/endoscope. Nous avons identifié 60 micro- organismes. Pseudomonas sp. est la bactérie la plus fréquemment rencontrée dans nos prélèvements (35 %), Acinetobacter sp. (13 %), Micrococcus sp. (17,5 %), Escherichia sp. (15 %), Staphylococcus sp.et Streptococcus sp. (11 %), Bacillus sp. (6 %), et Candida sp. (3 %). La modification dans la procédure de désinfection adoptée dans le service a permis de ramener la contamination à un niveau cible (FMAT < 10 UFC/endoscope). Le respect des principes de bases de l’hygiène hospitalière et l’application de procédures de nettoyage et de désinfection rigoureuses sont des éléments majeurs dans la prévention et la lutte contre les infections nosocomiales

Corrosion Inhibition of 3003 Aluminum Alloy in Molar Hydrochloric Acid Solution by Olive Oil Mill Liquid By-Product

According to the literature, the works on the inhibition of aluminum alloy corrosion using naturally occurring compounds are limited. For this, the inhibiting effect of oil mill liquid by-product (OMW) on the corrosion of 3003 aluminum alloy (AA3003) in molar hydrochloric acid solution was evaluated using electrochemical techniques. In parallel, a computational approach based on DFT/B3LYP and Monte Carlo methods was used to understand the inhibition process under electronic and atomic scales, respectively. The experimental results reveal that OMW has a good inhibiting effect on the corrosion of AA3003 alloy in the tested solution and acts as a cathodic inhibitor. The inhibitory efficiency increases by increasing OMW concentration to attain 89% at 6.0 ppm. The effect of temperature shows that the inhibition efficiency of OMW decreases with temperature rising. Nevertheless, a good prevention capacity of 83% is obtained at 338 K. Such interesting achieved protection property was attributed to the adsorption of OMW constituents onto the alloy surface via a mixed physichemisorption process. This process is found to obey the Langmuir adsorption isotherm. Furthermore, the activation thermodynamic parameters of the corrosion process of AA3003 alloy were also determined and discussed. The computational outcomes outlined the ability of the OMW components to interact favorably with the metal surface, hence the formation of a protective layer, which justified the observed inhibition behaviors. Conferring to the present study, OMW can be used as a good green corrosion inhibitor for AA3003 alloy in the acidic medium