21 research outputs found
Reconstruction 3D de sténoses par modélisation markovienne à partir de plus de deux images d'angiographie rotative par rayons X
No full text- Dans cette contribution, nous proposons une méthode de reconstruction tridimensionnelle (3D) locale de sténoses à partir de plus de deux images ou projections extraites d'une séquence d'images d'angiographie rotative par rayons X. Cette méthode utilise une modélisation markovienne dont l'énergie comprend un terme décrivant l'a priori sur la structure vasculaire à reconstruire ainsi qu'un terme d'ajustement aux projections. Cette modélisation est une généralisation de celle introduite dans [1]. En effet, l'énergie d'ajustement est modifiée afin de prendre en compte un nombre de projections supérieur à deux. Cette généralisation augmente le nombre de contraintes ce qui diminue le nombre de minima globaux de l'énergie markovienne. Les simulations réalisées dans ce travail montre que cela améliore sensiblement la qualité de la reconstruction dans le cas de présence de sténoses de formes complexes
Novel N-Heterocyclic Carbene Silver(I) Complexes: Synthesis, Structural Characterization, Antimicrobial and Cytotoxicity Potential Studies
No full textIn this study, a series of unsymmetrical N,N-disubstituted benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) (2a-2j) and their Ag-I complexes. Their structures were characterized by elemental analyses, H-1 and C-13 nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy techniques. Further, both the salts and their silver(I)-NHC complexes have been evaluated for their potential antibacterial properties against a panel of bacterial strains namely, Micrococcus luteus, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus and Pseudomonas aeruginosa. The results show that silver complexes are effective against Salmonella Typhimurium, Listeria monocytogenes, and Micrococcus luteus with moderate to high activity, and their minimum inhibitory concentrations ranging from 0.0034 to 1.26 mg mL(-1). In addition, the benzimidazoles salts 2a-2j and silver-NHC complexes 3a-3j were screened for their antitumor activity. Complex 3e exhibited the highest antitumor effect with half-maximal inhibitory concentration (IC50) value of 4.2 mu g mL(-1) against MCF-7.King Saud University, Riyadh, Saudi Arabia [RSP2019/75]This work was supported by the Research Supporting Project (RSP2019/75), King Saud University, Riyadh, Saudi Arabia
The use of newly isolated<i>Streptomyces</i>strain TN258 as potential biocontrol agent of potato tubers leak caused by<i>Pythium ultimum</i>
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Oxydation humide des polluants organiques par l'oxygène moléculaire activée par le couple H²O²/Fe²+: Optimisation des paramètres opératoires
No full textL'oxydation humide par l'oxygène moléculaire (procédé WAO) activée par le couple (H202/Fe2+) a été mise en oeuvre pour l'oxydation de la pollution organique aqueuse à travers deux composés modèles: l'acide succinique, normalement oxydable, et l'acide acétique, réputé réfractaire. L'influence des différents facteurs a été étudiée par la planification d'expériences. Après leur recensement, une étape préliminaire de criblage a été menée à bien en utilisant une matrice de Plackett et Burman. Seuls les paramètres les plus influents ont été gardés pour l'étape ultérieure d'établissement de modèles prévisionnels à partir d'une matrice composite centrée orthogonale. Les modèles établis ont été validés et ont permis de déterminer les conditions optimales de fonctionnement. L'effet de la température fait apparaître un optimum, à environ 200 °C, au-delà duquel la décomposition du peroxyde devient trop rapide. L'effet de la quantité de peroxyde d'hydrogène introduit est déterminant et l'ajout de moins de 20 % de la quantité stoechiomé- trique permet d'obtenir à 200 °C, avec environ 10 ppm de sels de fer, une efficacité de traitement d'environ 70% pour un composé normalement oxydable. Dans des conditions analogues, le procédé conventionnel sans promoteur conduit à une efficacité inférieure à 5 %.Wet air oxidation (WAO) is a liquid phase oxidation process using molecular oxygen at high temperature (250-300°C) and high pressure (50-150 bar). It can help treating toxic organic aqueous wastes from chemical industries with efficiencies up to 98% after 1 hour. The process can also help treating sludges from domestic sewage treatment facilities. It is usually very cost effective because of the very high operating pressure.This paper deals with the promoted wet air oxidation of acetic acid, rnodel compound for refractory wastes, and succinic acid, model for readily oxidized wastes. The study was conducted in order to determine the promoting effect when adding small dosages of hydrogen peroxide (with iron salts) during oxidation by molecular oxygen. It was previously shown that the initiating step is very temperature dependent (Reaction I) and limits the overall oxidation process The addition of small amounts of H2O2/Fe2+ (Fenton's reagent) can promote the forrnation of very reactive OH• radicals able to develop R• radicals (Reaction IV), even at a low temperature. Then, the oxidation (Reactions VI and VII) continues using molecular oxygen, but the peroxide should be added continuously during a batch test in order to maintain the initiating step.An optimal design methodology was used in order to assess the dependency of the oxidation effrciency on the various parameters and mainly on the promotors. At frrst, a Plackett and Burman design of experiments (PE1) was used to screen the most important variables among those likely to have an effect. The design of experiments, the conditions of the runs and the results (tables 1 to 3) allowed the determination of a new experimental domain and the selection of the four most important variables for the further design of experiments. At the same time, the effect of an addition of phenol (able to reduce iron to the ferrous species, more efficient) was considered. For succinic acid oxidation, a central composite optimal design (PE2) was used (tables 4 and 5). The results allowed us to establish a predictive model (Relationship lX, table 6 and figure 2) and typical results are presented in figures 3 and 4. Approximately 50% oxidation efficiencies could be obtained at 200°C; without peroxide addition, only 5% efficiency is obtained under similar conditions. Moreover, it was observed that the optimum temperature is around 205°C and that phenol is not compatible with peroxide as a promotor. A third optimal design (PE3) was used to predict the efficiency of the method for the treatrnent of acetic acid, a model for a refractory waste. It is composed only of a fractional factorial design (table 7 and 8) and the bias corresponds to the main quadratic effect of temperature (Relationship XIII and table 10). The optimum temperâture is also 205°C and greater than 20% oxidation efficiencies are obtained; at such a temperature, acetic acid cannot be oxidized with the conventional process.The results obtained for the two model compounds validate this oxidation technique. The addition of about 10 ppm of ferrous iron and of less than 20% of the stoichiometric amount in hydrogen peroxide can turn a high pressure WAO process into a medium pressure one
13C NMR study of the effect of aerobic treatment of olive mill wastewater (OMW) on its lipid-free content
No full textOlive mill wastewater was treated by an aerobic bio-process at different values of pH (with or without addition of lime), for 45 days on a laboratory scale, to evaluate the reduction of the organic load. The lipid content showed an appreciable change in relation to the applied treatment both for total lipids and for the different fractions (neutral lipids, monoglycerides and phospholipids). 13C NMR spectroscopy was performed on initial and final samples both raw and after lipid extraction. The main spectral differences were observed in the C-alkyl region (0–50 ppm), in the C O-alkyl/N-alkyl region (50–110 ppm), and in the C-carboxylic (160–200 ppm) region, providing information on the alterations occurring in the different biochemical entities composing this complex biomatrix (e.g. lipids and carbohydrates) according to the treatment
Copper-catalyzed azide–alkyne cycloaddition (CuAAC) under mild condition in water: Synthesis, catalytic application and biological activities
No full textThe impact of curved-tip propeller geometry on hovering drone performance for air quality monitoring
No full textInternational audienceThe success or failure of a drone mission depend on several elements, including the drone’s mass and payload, the surrounding environment, the battery’s state, and the propulsion system’s performance. Several studies have been undertaken addressing the propeller performance of this final component, particularly for fixed-wing or quad copter drones with ducted propellers. However, the shape of propeller blades used on tiny civil drones has not drawn as much attention. In this research work, the performance characteristics of a 10 × 4.7-inch curved tip propeller were explored, with the Advanced Precision Composite drone propeller serving as a design reference. This study seeks an alternative to ducted propellers when mass or size limitations prevent their use. The Computational Fluid Dynamics model was confirmed by comparing simulation results to the experimental propeller data source established by the University of Illinois at Urbana-Champaign, starting with a standard type propeller and using thrust coefficient as the key performance indicator. Moreover, the data analysis for the bended tip propeller replicating the well-established model, revealed the benefits as well as the drawbacks of such propellers on the mission profile and the battery lifespan of a quad copter Unmanned Air Vehicle
HYPERTENSION MANAGEMENT IN TUNISIAN ELDERLY PEOPLE (ABOUT A COHORT OF 1572 CASES): PP.7.276
No full textIR spectroscopic observation windows and analysis for environmental issues: application to CO2
No full textInternational audienceUnderstanding the phenomena that can occur in a given medium necessitates a clear grasp of its chemical composition. In this context, various techniques including infrared (IR) spectroscopy were developed. In this work, we determined the bond force constants of CO2 molecule in gas phase state and trapped in a nanocage by applying group theory to the normal vibrational modes of the symmetric (16O12C16O, 626) and the asymmetric (16O12C18O, 628) CO2 isotopic species. Wilson’s force, F and inverse-mass, G matrices, were calculated for the CO2 (626 and 628) species. The effect of Fermi resonances was included in the analysis. Results are given in terms of bond force constants for stretching and bending modes of CO2 molecule trapped in nanocages of rare gas matrices and of clathrate hydrates. The comparison with the gas phase values demonstrated that the condensed phase effect can be constrained at the harmonic level. A database of vibrational frequencies can then be built from the calculated values with a pseudo-uncertainty range to enhance automatic analysis of observed data pertaining to CO2 in an unknown media by IR sensors. The study of CO2 trapped in nanocages using group theory to calculate force constants has received little theoretical consideration in previous works. Here, we provide an additional approach to evaluate the uncertainty measurement in IR spectroscopy. Similar outcomes should be achievable for other molecules, providing the possibility to improve spectroscopic IR observation and analysis from sensors specially designed for mobile sensing applications
