Inhibiting effects of 2-mercapto-1-methylimidazole on copper corrosion in 0.5M sulfuric acid

AbstractThe inhibiting efficiency of 2-mercapto-1-methylimidazole (MMI) on copper corrosion in sulfuric acid was investigated at 30°C. Its effectiveness was assessed through electrochemical impedance spectroscopy, potentiodynamic polarization and gravimetric measurements. The results of study reveal that the inhibition efficiency of MMI depends on its concentration and attains approximately 81% at 10−4M. The inhibitor was adsorbed on the copper surface according the Langmuir adsorption isotherm model. The value of standard free energy of adsorption was calculated from this isotherm

Research Paper Polyclonal antibodies production against Staphylococcus aureus protein A: ELISA technique optimization for milk quality control

The main aim of this project is to produce polyclonal antibodies directed against the Staphylococcus aureus protein A and their use to appreciate bacteriological analysis of milk quality. In this context, an immunization produce was set up to test and detect in a batch of animals the convenient responder to the injected antigen. Furthermore, to optimize all parameters of retained ELISA test, a cross-table was conceived by using various concentrations of different reagents and has allowed selecting the optimaldilutions as follows: 1) 1/1000 for anti-Staphylococcus aureus protein A mouse antibodies and 1/2000 for anti-Staphylococcus aureus protein A rabbit antibodies. 2) 1/4000 for anti-Staphylococcus aureus treated by heat mouse antibodies and 1/500 for anti-Staphylococcus aureus protein A rabbit antibodies. 3) 1/2000 for anti-Staphylococcus aureus treated by NaClO mouse antibodies and 1/500 for anti-Staphylococcus aureus protein A rabbit antibodies. The application of optimized ELISA test to searchand detect Staphylococcus aureus germs in different samples of milk has shown very satisfying results when compared to those obtained by bacteriological method. Indeed, the sensitiveness and the reproducibility, as well as the possibility to analyze a great number of samples in the same time at a reduced manner make the immunochemical method a best choice of test able to replace recent bacteriological methods

Deflection angle and Shadows by Black Holes in Starobinsky-Bel-Robinson Gravity from M-theory

Motivated by M-theory compactifications, we investigate optical properties of black holes in the Starobinsky-Bel-Robinsion gravity. Precisely, we study the shadows and the deflection angle of light rays by non-rotating and rotating black holes in such a novel gravity. We start by discussing the shadows of the Schwarzschild-type solutions. As expected, we obtain perfect circular shadows where the size decreases with a stringy gravity parameter denoted by $\beta$. We show that this parameter is constrained by the shadow existence. Combining the Newman-Janis algorithm and the Hamilton-Jacobi mechanism, we examine the shadow behaviors of the rotating solutions in terms of one-dimensional real curves. Essentially, we find various sizes and shapes depending on the rotating parameter and the stringy gravity parameter $a$ and $\beta$, respectively. To inspect the shadow geometric deformations, we investigate the astronomical observables and the energy emission rate. As envisaged, we reveal that $a$ and $\beta$ have an impact on such shadow behaviors. For specific values of $a$, we remark that the obtained shadow shapes share certain similarities with the ones of the Kerr black holes in plasma backgrounds. Using the Event Horizon Telescope observational data, we provide predictions for the stringy gravity parameter $\beta$ which could play a relevant role in M-theory compactifications. We finish this work by a discussion on the behaviors of the light rays near to such four dimensional black holes by computing the deflection angle in terms of a required moduli space.Comment: Latex, 27 pages, 10 figures. Authors in alphabetical orde

Antioxidant activity of phenolic extracts from olive mill wastewater and their influence on virgin olive oil stability

Fresh olive oil mill wastewaters (OMW) were collected in northern Morocco from industrial mills operating with three extraction systems (dual [C2] and triple phase [C3] centrifugation decanters and super-pressure system [SP]) during the 2017 growing season. Physicochemical and microbiological characteristics of these effluents were examined. OMW phenolic extracts were prepared and their antioxidant activities were evaluated. Moreover, the improvement of virgin olive oil stability by the addition of OMW phenolic extracts (at 100, 300 and 500 ppm) was investigated. Results from the present work confirmed the pollutant load of these effluents characterized by an acidic pH, strong organic content, and considerable amounts of mineral matter. Concerning the microbiological counts, yeasts and molds were the most abundant. Among extraction system, C2 displayed OMW with the high levels for all measured parameters, except for total phenols that were more abundant in C3. Findings from DPPH and FRAP tests showed a good antiradical potential and an important reducing power capacity and were both concentration-dependent. For the two tests, antioxidant activity of OMW phenolic extracts from C2 was the most important. The addition of phenolic extracts to virgin olive oil, stocked at 60°C, resulted in lower values of PV, K232 and K270 compared to the control, indicating a good protective effect against oil oxidation. The great antioxidant effect of OMW extracts was at 500 ppm, similar to that of ascorbic acid

Light Behaviors around Black Holes in M-theory

We study the deflection angle and the trajectory of the light rays around black holes in M-theory scenarios. Using the Gauss-Bonnet theorem, we first compute and examine the deflection angle of the light rays near four and seven-dimensional AdS black holes obtained from the M-theory compactifications on the real spheres on $S^7$ and $S^4$, respectively. We discuss the effect of the M-theory brane number and the rotating parameter on such an optical quantity. We then investigate the trajectories of the light rays using the equation of motion associated with $M2$ and $M5$ branes.Comment: Latex, 22 pages, 8 figure

Composition en antioxydants et activité coagulante des artichauts sauvage et cultivé au Maroc (Cynara cardunculus L.)

Natural plant extracts are sustainable alternatives to chemical food additives with less side effects. Wild and cultivated artichoke bracts (cynara cardunculus L.) were evaluated for their bioactive content and scavenging activity on two stages (bracts stage) I and (full bloom stage) II. Head flowers were collected from the second stage and analyzed for their coagulating properties. Phenolic compounds, flavonoids total content in bracts extracts of wild artichoke significantly exceeded those of the cultivated plant; a decrease of these compounds was noted from stage I to stage II for both plants. Flowers Enzymatic extract of both plants exhibited a reduced clotting time and a lower proteolytic activity. Indeed, 280 μg tyr / ml was measured for microbial rennet, 90 μg tyr / ml for the wild artichoke flower extract and 85 μg tyr / ml for the cultivated artichoke flower. This study revealed the potential interest of valorization of artichoke different parts commonly considered as dietary waste in different food and health applications.Les extraits naturels de plantes sont des alternatives durables aux additifs alimentaires chimiques avec moins d'effets secondaires. Les bractées d'artichaut sauvage et cultivé (cynara cardunculus L.) ont été évaluées pour leur teneur en composés bioactifs et leur activité de piégeage sur deux stades (stade des bractées) I et (stade de pleine floraison) II. Les fleurs des capitules d’artichaut ont été récoltées en pleine floraison et analysées pour leurs propriétés coagulantes. Les résultats ont démontré que les composés phénoliques, les teneurs en flavonoïdes dans les extraits de bractées d'artichaut sauvage dépassaient significativement celles de la plante cultivée ; une diminution de ces composés a été notée du stade I au stade II pour les deux plantes. L'extrait enzymatique des fleurs des deux plantes a présenté un temps de coagulation réduit et une activité protéolytique plus faible. En effet, 280 μg tyr/ml a été mesuré pour la présure microbienne, 90 μg tyr/ml pour l'extrait de fleur d'artichaut sauvage et 85 μg tyr/ml pour la fleur d'artichaut cultivée. Cette étude a révélé l'intérêt potentiel de la valorisation des différentes parties de l'artichaut communément considérées comme des déchets alimentaires dans différentes applications alimentaires et de santé

CARACTERISATION D’HUILES D’OLIVE PRODUITES DANS DES COOPERATIVE PILOTES (LAKRARMA ET KENINE) AU NIVEAU DU MAROC ORIENTAL

In Eastern Morocco, olive tree growing has agreat economic and social importance. Itoccupies about 10% of the national olivegrowingsurface. Olive oil is the principalproduct; more than 70% of the olive productionis intended to trituration. In this region most ofthe olive orchards were established andcultivated by traditional methods, and olive oilextraction is generally carried out by artisanalmethods which can compromise its quality.Classical methods of analysis were used for apreliminary characterisation of olive oilproduced by regional cooperatives (Lakrarma,Kenine localised in Taourirt-Tafoughalt corridor). Analyses relating to free acidity, peroxide index, chlorophyll content and standardvalues of absorption, were realized. In comparison with International Olive Oil Council our results showed that analyzed olive oils have physico-chemical characteristics of a virgin orextra virgin olive oil.Au niveau du Maroc oriental l’oléiculturerevêt une grande importance économique et sociale, elle représente un peu moins de 10% de la superficie oléicole nationale. L’huile d’olive est le principal produit, du fait que plus de 70% de la production oléicole est destinée à la trituration. Dans cette région, la filière reste encore artisanale et mal organisée. L’extraction de l’huile d’olive s’effectue généralement par des méthodes traditionnelles qui peuvent compromettre sa qualité. Pour la caractérisation d’huile d’olive, provenant des coopératives régionales (Lakrarma, Kenine) du couloir Taourirt Tafoughalt, des analyses physicochimiques concernant l’acidité libre, l’indice de peroxyde, la teneur en chlorophylle et les valeurs standards d'absorption en UV ont été réalisées. Les résultats obtenus et selon la norme commerciale du Conseil Oléicole International, montrent que les huiles analysées possèdent des caractéristiques physicochimiques d’huile d’olive vierge à extra vierge

Zirconia and hafnia polymorphs: Ground-state structural properties from diffusion Monte Carlo

Zirconia (zirconium dioxide) and hafnia (hafnium dioxide) are binary oxides used in a range of applications. Because zirconium and hafnium are chemically equivalent, they have three similar polymorphs, and it is important to understand the properties and energetics of these polymorphs. However, while density functional theory calculations can get the correct energetic ordering, the energy differences between polymorphs depend very much on the specific density functional theory approach, as do other quantities such as lattice constants and bulk modulus. We have used highly accurate quantum Monte Carlo simulations to model the three zirconia and hafnia polymorphs. We compare our results for structural parameters, bulk modulus, and cohesive energy with results obtained from density functional theory calculations. We also discuss comparisons of our results with existing experimental data, in particular for structural parameters where extrapolation to zero temperature can be attempted. We hope our results of structural parameters as well as for cohesive energy and bulk modulus can serve as benchmarks for density-functional theory based calculations and as a guidance for future experiments