Le gecko : une figure du décentrement

La société angolaise voit la coexistence d’une société créole, qui vit à Luanda (monde citadin et moderne), et de sociétés traditionnelles. La première a servi de laboratoire expérimental à la classe politique et gouvernante qui a décidé d’inculquer les valeurs créoles, d’encourager le mélange racial et ethnique, de faire adopter la langue portugaise à toute la nation et ce en créant le concept « d’angolanité ». La prétention d’un tel projet sera au cœur des débats qui traversent la littérature angolaise actuelle.  « Si on veut comprendre ce qui se passe aujourd’hui en Angola, on doit connaître son passé, selon José Edouardo Agualusa qui renchérit que l’Angola actuelle n’est pas celle qu’on nous avait promise. Ceux qui se sont battus pour son indépendance considèrent que ce n’est pas cette Angola qu’ils souhaitaient » (Entretien avec l’écrivain José Edouardo Agualusa par Dominique Stoenesco, Luso Journal, octobre 2011).  Cette déclaration d’Agualusa nous aura permis de comprendre que son écriture a pour finalité d’interroger le passé sans qui l’identité n’existerait pas. Il fait partie de cette génération d’écrivains angolais qui font appel, d’après certaines critiques africanistes, au « réalisme africain » où la référence historique se mêle à la satire sociale.  En effet, deux cas de figure se posent en Angola à savoir les anciennes familles créoles (leur mémoire est faite de richesses et de pouvoir) face au nouveaux riches qui le sont devenus illégalement et qui sont à la recherche d’une nouvelle mémoire qui leur permettrait de justifier leur enrichissement rapide et ce sont ces gens- là qui constituent les clients du Marchand de passés 

Stalk formation as a function of lipid composition studied by X-ray reflectivity

AbstractWe have investigated the structure and interaction of solid-supported multilamellar phospholipid bilayers in view of stalk formation as model systems for membrane fusion. The multi-component bilayers were composed of ternary and quaternary mixtures, containing phosphatidylcholines, phosphatidylethanolamines, sphingomyelin, cholesterol, diacylglycerol, and phosphatidylinositol. Analysis of the obtained electron density profiles and the pressure–distance curves reveals systematic changes in structure and hydration repulsion. The osmotic pressure needed to induce stalk formation at the transition from the fluid lamellar to the rhombohedral phase indicates how membrane fusion properties are modified by bilayer composition

The impact of cigarette/e-cigarette vapour on simulated pulmonary surfactant monolayers under physiologically relevant conditions

Deviation in pulmonary surfactant structure–function activity can impair airway patency and lead to respiratory disorders. This novel study aims to evaluate the influence cigarette/e-cigarette vapour has on model surfactant films located within a simulated pulmonary environment using a lung biosimulator. Chromatographic analysis confirmed that nicotine levels were consistent with the sampling regimen employed. On exposure to smoke vapour, Langmuir isotherms exhibited condensed character and a significant reduction in maximum surface pressure was noted in all cases. Langmuir isocycles, reflective of the human breathing cycle, demonstrated condensed character on smoke vapour delivery. A reduction in themaximumsurface pressure was clear only in the case of cigarette vapour application. The components of cigarette vapour can cause oxidative damage to pulmonary surfactant and impair recycling. Neutral nicotine molecules can weaken the structure of the monolayer and cause destabilisation. A protective effect was evident in the case of repeated surfactant compression – relaxation cycles (i.e. the ability to reduce the surface tension term was impaired less), demonstrating a likely innate biological defensive mechanism of the lung. E-cigarette vapour appeared to have a reduced impact on surfactant performance, which may hold value in harm reduction over the longer term

The pH Dependent Interaction between Nicotine and Simulated Pulmonary Surfactant Monolayers with Associated Molecular Modelling

Pulmonary surfactant is an endogenous material that lines and stabilises the alveolar air-liquid interface. Respiratory mechanics can be compromised by exposure to environmental toxins such as cigarette vapour, which contains nicotine. This study aims to determine the influence of nicotine on the activity of simulated lung surfactant at pH 7 and pH 9. In all cases, the addition of nicotine to the test zone caused deviation in surfactant film performance. Importantly, the maximum surface pressure was reduced for each system. Computational modelling was applied to assess key interactions between each species, with the Gaussian 09 software platform used to calculate electrostatic potential surfaces. Modelling data confirmed either nicotine penetration into the two-dimensional structure or interfacial / electrostatic interactions across the underside. The results obtained from this study suggest that nicotine can impair the ability of pulmonary surfactant to reduce the surface tension term, which can increase the work of breathing. When extrapolated to gross lung function alveolar collapse and respiratory disease (e.g. chronic airway obstruction) may result. The delivery of nicotine to the (deep) lung can cause a deterioration in lung function and lead to reduced quality of life

Tailoring a symmetry for material properties of tellurite glasses through tungsten(vi) oxide addition: Mechanical properties and gamma-ray transmissions properties

We report a correlation outcome for mechanical and gamma-ray transmission properties of tellurite glasses by increasing tungsten(vi) oxide concentration in glass structure. The mechanical properties as well as Poisson's ratio (σ) of the studied glasses are estimated by applying Makishima-Mackenzie model. Gamma-ray attenuation properties using various fundamental parameters are determined in 0.015-15 MeV energy range. Poisson's ratio (σ) decreased from 0.43017 to 0.42711, while all elastic moduli increased linearly with the molar increment of either [WO3] or [TeO2] in the molecular structure of the glass network. Moreover, gamma-ray attenuation properties are enhanced as a function of increasing WO3 substitution amount from 30 to 50% mol in the glass structure. Half-value layer values at 15 MeV are found to be between 2.648 and 2.8614 cm. I4 samples with a composition of 20TeO2-50WO3-30GdF3 and density of 6.0530 g/cm3 was found to have superior material properties in terms of elastic and gamma-ray attenuation properties. It can be concluded that maximized WO3 contribution into the tellurite glasses may be considered as a critical tool in terms of establishing a symmetry between mechanical and gamma-ray attenuation properties for high-density tellurite glasses for their potential utilization in nuclear waste management, radiation shielding, and radioactive source transportation purposes. © 2023 the author(s), published by De Gruyter

A Promising Glass Type in Electronic and Laser Applications: Elastic Moduli, Mechanical, and Photon Transmission Properties of WO3 Reinforced Ternary-Tellurite Glasses

We report the symmetry of mechanical and gamma-ray attenuation properties for some tellurite glasses through elastic moduli, mechanical, and transmission properties as a function of varied WO3 amount in glass configuration. Four glass samples, along with different molar compositions as well as WO3/GdF3 substitution ratios, are investigated. Transmission properties using several essential parameters, such as attenuation coefficients, half-value layers, effective atomic numbers, effective conductivity, and buildup factors, are calculated in the 0.015–15 MeV energy range. Moreover, elastic moduli and Poisson’s ratios (σ) of the studied glass are calculated using the Makishima–Mackenzie model. The M4 sample with the highest WO3 addition is found with superior photon attenuation properties among the glasses investigated. Poisson’s ratio (σ) is increased, while all elastic moduli are decreased. Young’s modulus is reported as 62.23 GPa and 36.45.37 GPa at the highest and lowest WO3 mol%, respectively. It can be concluded that WO3 is a functional and monotonic tool in ternary-tellurite glasses for multiple modifications and enhancement purposes on gamma-ray attenuation, elastic moduli, and mechanical properties. It can also be concluded that increasing the WO3 amount in tellurite glasses may be considered a tool in terms of providing symmetry for mechanical and gamma-ray attenuation properties. © 2023 by the authors.PNURSP2023R149; Princess Nourah Bint Abdulrahman University, PNUPrincess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2023R149), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Effect of bilayer charge on lipoprotein lipid exchange

Lipoproteins play a key role in the onset and development of atherosclerosis, the formation of lipid plaques at blood vessel walls. The plaque formation, as well as subsequent calcification, involves not only endothelial cells but also connective tissue, and is closely related to a wide range of cardiovascular syndromes, that together constitute the number one cause of death in the Western World. High (HDL) and low (LDL) density lipoproteins are of particular interest in relation to atherosclerosis, due to their protective and harmful effects, respectively. In an effort to elucidate the molecular mechanisms underlying this, and to identify factors determining lipid deposition and exchange at lipid membranes, we here employ neutron reflection (NR) and quartz crystal microbalance with dissipation (QCM-D) to study the effect of membrane charge on lipoprotein deposition and lipid exchange. Dimyristoylphosphatidylcholine (DMPC) bilayers containing varying amounts of negatively charged dimyristoylphosphatidylserine (DMPS) were used to vary membrane charge. It was found that the amount of hydrogenous material deposited from either HDL or LDL to the bilayer depends only weakly on membrane charge density. In contrast, increasing membrane charge resulted in an increase in the amount of lipids removed from the supported lipid bilayer, an effect particularly pronounced for LDL. The latter effects are in line with previously reported observations on atherosclerotic plaque prone regions of long-term hyperlipidaemia and type 2 diabetic patients, and may also provide some molecular clues into the relation between oxidative stress and atherosclerosis

Majida Khattari : Le défilé de mode

Khattari Majida. Majida Khattari : Le défilé de mode. In: Les Cahiers du GRIF, Hors-Sérien°2, 1996. Âmes fortes, esprits libres. pp. 128-128

Kacha (Cover)

general vie

L'épanouissement de l’individu dans Ia nouvelle littérature marocaine d'expression française: L'homme qui descend des montagnes de Serhane et Le fond de la jarre de Laâbi

This article provides a study of Abdelhak Serhane's The Man Who Descends from the Mountains and The Bottom of the Jar by Abdellatif Laâbi. While religion and tradition have had a long impact on the Arab and Muslim countries, the argument is made that the new Moroccan literature is mediating the birth of a new subject who interacts with his/her environment with the aim of constructing and bestowing meaning on the world to which they belong. Besides, Maghrebi (North African) literature is both a response and a challenge to the order that has long been dominant. The author shows how the stifling authority of the patriarch which has long been revered is now challenged. Through a study of the two novels, the author traces the markers of an emergent narrative of new subjectivities