Manifestations neurologiques de l’infection par SARS-Cov-2

L'apparition en décembre 2019 du coronavirus SARS-Cov-2 (severe acute respiratory syndrome coronavirus 2) responsable de l'infection COVID-19, a totalement bouleversé le système de santé et a entrainé une situation inédite tant sur le plan scientifique que social. Depuis sa propagation rapide à travers le monde et sa qualification de pandémie par l'Organisation mondiale de la santé (OMS), l'explosion du nombre de cas de COVID-19 a permis de décrire plusieurs formes cliniques concomitantes avec les mutations de ce virus. Bien que le COVID19 soit surtout connu pour son tropisme respiratoire (syndrome respiratoire aigu impliquant les voies aériennes supérieures ou basses), il peut également provoquer plusieurs atteintes extrapulmonaires telles que les manifestations neurologiquesL'apparition en décembre 2019 du coronavirus SARS-Cov-2 (severe acute respiratory syndrome coronavirus 2) responsable de l'infection COVID-19, a totalement bouleversé le système de santé et a entrainé une situation inédite tant sur le plan scientifique que social. Depuis sa propagation rapide à travers le monde et sa qualification de pandémie par l'Organisation mondiale de la santé (OMS), l'explosion du nombre de cas de COVID-19 a permis de décrire plusieurs formes cliniques concomitantes avec les mutations de ce virus. Bien que le COVID19 soit surtout connu pour son tropisme respiratoire (syndrome respiratoire aigu impliquant les voies aériennes supérieures ou basses), il peut également provoquer plusieurs atteintes extrapulmonaires telles que les manifestations neurologique

Amelioration De La Maturite Des Entreprises En Gestion Des Risques Par La Maintenance

Statistics on accidents at work, particularly in Morocco, remain worryingly high. This situation raised a general awareness in the country and many decisions have been taken and corrective actions have been elaborated in order to enhance enterprise risk management maturity. This maturity is based on several key factors including maintenance.In this paper we propose a methodology to mitigate and control maintenance generated risks which in turn will allow enterprises to enhance their maturity in risk management

The Effect of NiNO3 on Optical Properties for (PVA- PEG) Composites Polymers

The present paper is aimed to modification of the optical properties of poly-vinyl alcohol and poly-ethylene glycol with different concentrations of ( NiNO3). The absorption and transmission spectra have been recorded in the wavelength range     (200-800)nm . The absorption coefficient and energy gap of the indirect allowed and forbidden transition have been determined, Also, extinction coefficient, index coefficient, real and imaginary part of dielectric constant have been calculated. Keywords: optical properties, polymer composites, optical constants, polyethylene glycol

Evaluation of the Physical Stability of Zinc Oxide Suspensions Containing Sodium Poly-(acrylate) and Sodium Dodecylsulfate.

The physical stability of zinc oxide (ZnO) aqueous suspensions has been monitored during two months by different methods of investigation. The suspensions were formulated with ZnO at a fixed concentration (5 wt%), sodium poly-(acrylate), as a viscosifier, and sodium dodecylsulfate (SDS), as a wetting agent. The rheological study shows that the suspensions exhibit a non-Newtonian, most often shear-thinning behavior and their apparent viscosity increases with polymer concentration. The rheograms of most of the ZnO suspensions do not vary during the experimental period. The viscoelastic properties of these suspensions, such as elastic or storage modulus (G′), viscous or loss modulus (G″) and phase angle (δ) were also examined. For% strains lower than 10%, all the formulations show strong elastic properties (G′ > G″, δ varies between 5 and 15°). Beyond 10% strain, the rheological behavior changes progressively from elastic to viscous (G″ > G′ for % strain >80%). Consistently, δ increases and reaches the 50–70° zone. Multiple light scattering (back-scattered intensity), measured with the Turbiscan ags, was used to characterize suspension physical stability (early detection of particle or aggregate size variations and particle/aggregate migration phenomena). Suspensions containing 0.4 and 0.6 wt% polymer remain stable and macroscopically homogeneous, without being affected by the change of particle size observed with a laser particle sizer. Sedimentation tests, pH, and ζ potential measurements versus time, also confirmed these findings

Study of the effect of rare-earth oxide addition on the magnetic and dielectric properties of Sr-hexaferrites

Magnetic and dielectric properties of M-type Sr-hexaferrites of composition (SrO)1-x (La2O3)x 5.7 Fe2O3, where x = 0.00, 0.04, 0.08 prepared by conventional ceramic technology at different sintering temperatures using magnetite of Cox’s Bazar beach sand, Bangladesh have been investigated in the present work. Investigations have been carried out by permeability, loss tangent, quality factor and dielectric constant measurements of various samples of Sr-hexaferrites with the addition of La2O3. In our entire study, magnetic and dielectric properties of Srhexaferrites have been found to be strongly dependent upon the additives, temperature and frequency

Preparation and Study of Optical Properties of (Polymer-Nickel Nitrate) Composite

Polymer composite of polyvinyl alcohol (PVA), nickel nitrate  have been prepared by solution cast method for different doping concentrations of nickel nitrate. The optical characterization has been done by analyzing the absorption spectra in the spectral region 200–800 nm. It was found that the optical energy gap decreases with increasing NiNO3 content.  The refractive index (n), extinction coefficient (k), static dielectric constant have been calculated for the investigated films. The optical constants are changing with increase the weight percentages of nickel nitrate. Key words: composite, polymer,  optical constants, nickel nitrate 

Studying the Effect of KCl Addition on the Electrical Properties of Polystyrene

In this work, samples of pure polystyrene and polystyrene (PS) doped with (KCl) were prepared using casting method .The effect of addition of different concentrations of potassium chloride on electrical properties of polystyrene have been studied, also the effect of temperature on (PS-KCl) composite , then the variation of activation energy of D.C electrical conductivity with KCl concentrations was studied. The results show that the electrical conductivity was increased with increasing the KCl concentration and temperature and the activation energy was decreased with increasing KCl concentration. Key words: polymer, PS, potassium chloride, electrical properties, conductivity

Numerical Study on Shear Stress Variation of RC Wall with L Shaped Section

In recent years, and after the 2003 Boumerdes earthquake, a new type of building is being constructed in Algeria. The new concept is based on the concentration of reinforced concrete shear walls with L shape at the building corners. The seismic behavior of such configuration is not well known nowadays. Numerical investigation was carried out on reinforced concrete structure to evaluate the stress distribution at the base of the corner L shaped walls. Influence of number of stories, length of the shear wall as well as the thickness of the wall was considered in our investigation. In total, more than 200 numerical models were crated and analyzed. The analyses showed that, reinforced concrete wall with 15 cm, or less, in thickness should have a minimum length of 10 times the thickness; however, for RC walls with a thickness of more than 20 cm, the length of the wall should be greater than 7  times the thickness. In this paper the main results of this investigation are presented

Analysis and Design of Plug Shape of an Aerospike Nozzle

The present work investigates the influence of gas at high temperature on the design and analysis of two-dimensional plug nozzle. The thermochemical and combustion studies of liquid launchers propellants make it possible to choose the gases to be studied. For example, four cases of bi-propellants engines have been studied. The combinations studied are: H2/O2, RP1/O2, CH4/O2 et MMH/N2O4. The selected gas are: CO2, H2O H2, N2 and CO. Once the profile is generated, an analysis of the thermodynamic-parameters evolution (such as: length, Mach number, mass, thrust coefficient) and aerodynamic performances is conducted. Some results were presented and compared with previous research using air. The comparison shows that the presence of H2O and CO2 gases considerably increases the performance of nozzles. The percentage of gases in the combustion has an influence on these increases. In order to minimize the weight of this nozzle, the truncation of Plug nozzle in order to increase their performances is studied in this research