ANTIBACTERIAL ACTIVITY AND GAS CHROMATOGRAPHY–MASS SPECTROMETRY STUDIES OF ALGERIAN ATRIPLEX HALIMUS L.

Objective: The objective of the study was to find out the antibacterial efficacy and identify the main constituents of the essential oil of Atriplex halimus from southwest of Algeria. Methods: The essential oil from the aerial parts of the endemic plant A. halimus (saltbush in English, qataf in Arabic) collected from the region of Sahara southwest of Algeria was isolated by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Antibacterial potency of essential oil from this plant has been tested against Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), and Bacillus cereus (ATCC11778) by disk diffusion assay. Results: The essential oil revealed the presence of 14 components, the dominant compounds arecadina-1(10), 4-diene (10.69%), germacrene D (9.79%), octane (9.37%), pelargonaldehyde (9.06%), 3-Furancarboxaldehyde (6.87%), β-pinene (2.6%), camphene (2.59%), and myrcene (2.10%). The essential oil exhibits very effective antimicrobial activity using disk diffusion assay method with minimum inhibitory concentration ranging from 0.82 μl/ml to 2.4525 μl/ml. Conclusions: This result showed that this native plant may be a good candidate for further biological and pharmacological investigations

CHEMICAL CHARACTERIZATION BY GC-MS FROM THE AERIAL PARTS OF FAGONIA LONGISPINA (ZYGOPHYLLACEAE)

Objective: The objective was to characterize the phytochemical constituents in ethyl acetate (EtOAc) extract from the aerial parts of Fagonia longispina(zygophyllaceae) by gas chromatography-mass spectrometry (GC-MS).Methods: The dried powder of the aerial parts of F. lonjispina was extracted exhaustively with ethanol. The extract was concentrated, diluted withwater and partitioned with EtOAc. The residue of the EtOAc extract was performed using a GC-MS.Results: Chemical constituents of the EtOAcextract of F. Longispina Family (Zygophylaceae) were identified by GC-MS and their relative concentrationswere determined. F. Longispina extract contained 12 compounds: Cis-4-(4 -T-butylcyclohexyl)-4-methyl-2-pentanone (33.33%), 4beta-(tert-butyl)1alpha-(1methylvinyl)cyclohexanemethanol (09.52%), cyclohexyl-2-methylenebutanylketone(14.28%),trans-4-(–t-butylcyclohexyl)-4-methyl2-pentanone(9.52%),2,6,10-trimetyl,14-Ethylne-14pentadecene (6.66%), 2-decen-1-ol(cas) (4.76%), 3,7,11,15-tetramethyl-2-hexadecen-1-ol(2.85%),2-nonen-1-ol (4.76%), citronellylacetate(2.85%), tetratetracontane(3.38%), hexatriacontane(cas) (3.38%), and phytolacetate(4.76%).'Conclusions: This GC-MS study helps to predict the formula and structure of phytoconstituents which can be used as drugs, and further investigationmay leads to the development of drug formulation. These compounds are probably the major players in the antioxidant responses evoked by the plant.Keywords: Etyl acetate extract, Gas chromatography-mass spectrometry analysis, Fagonia longispina

Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence

We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integrations of the model equations

Global Existence and Regularity for the 3D Stochastic Primitive Equations of the Ocean and Atmosphere with Multiplicative White Noise

The Primitive Equations are a basic model in the study of large scale Oceanic and Atmospheric dynamics. These systems form the analytical core of the most advanced General Circulation Models. For this reason and due to their challenging nonlinear and anisotropic structure the Primitive Equations have recently received considerable attention from the mathematical community. In view of the complex multi-scale nature of the earth's climate system, many uncertainties appear that should be accounted for in the basic dynamical models of atmospheric and oceanic processes. In the climate community stochastic methods have come into extensive use in this connection. For this reason there has appeared a need to further develop the foundations of nonlinear stochastic partial differential equations in connection with the Primitive Equations and more generally. In this work we study a stochastic version of the Primitive Equations. We establish the global existence of strong, pathwise solutions for these equations in dimension 3 for the case of a nonlinear multiplicative noise. The proof makes use of anisotropic estimates, $L^{p}_{t}L^{q}_{x}$ estimates on the pressure and stopping time arguments.Comment: To appear in Nonlinearit

Formulation and Optimization by Experimental Design of Low-Fat Mayonnaise Based on Soy Lecithin and Whey

The main objective of this study is to develop a new formula for a diet mayonnaise-like sauce without cholesterol. Emulsifying power is provided by the use of soy lecithin and the total fat content was limited to 16%. Droplet size measurement of employed mayonnaise samples at different times show that the largest diameter of fat does not exceed 18.5 µm with a yield stress of 56.1 Pa. Results of stability to centrifugation reveal that the absence of the supernatant oily layer ensures the stability of the emulsion. Using the experimental design method, the number of trials can be limited to a number of 16 experiments, and best formulation of the mayonnaise (without cholesterol) was obtained

Novel Technique for In-Body Absorbed Power Density Assessment Based on Free-Space E-Field Measurement

International audienceWe introduce a novel method for measurement of the absorbed power density (APD) above 6 GHz, accounting for antenna/body interaction. A reflectivity-based thin planar solid phantom is used to mimic the scattering characteristics of human skin. This allows to perturb the antenna under test (AUT) in a similar way as it would be perturbed by the presence of the human body. The lower electromagnetic losses in the phantom medium result in an enhanced transmission through the phantom facilitating free-space E -field vector measurement on the opposite to the AUT side of the phantom. The measured E -field is backpropagated in space to retrieve APD using a plane-wave spectrum (PWS) technique. The proposed method is validated at 60 GHz using reference antennas, namely, a cavity-fed dipole array and pyramidal horn with a slot array. A very good agreement is demonstrated between the target APD at the air/skin interface (peak, averaged, and spatial distribution) and the one reconstructed from the simulated and measured E -field. The maximum relative deviations between the computed and measured peak ( pAPD ), 1 cm 2 peak spatial average ( psAPD1cm2 ), and 4 cm 2 peak spatial average ( psAPD4cm2 ) are 13.2% (0.55 dB), 14.9% (0.6 dB), and 15.7% (0.63 dB), respectively. The results demonstrate that the proposed technique is promising for experimental dosimetry and compliance testing of wireless devices operating above 6 GHz

Quadratic phase modulation and diffraction-limited microfocusing generated by pairs of subwavelength dielectric scatterers

Diffractive approaches are needed when refractive microlenses reach their focusing limit at the micron-scale in visible light. Previously, we have reported on micron-sized optical lenses based on the diffraction of metallic nanowires. Here, we extend our study to lenses based on pairs of subwavelength dielectric scatterers. Using simulations by two-dimensional finite element method, we demonstrate that focusing holds for pair spacings as small as the wavelength-size. For pairs with distances between inner walls larger than about 1.2λ, the scattered waves generate a quadratic phase modulation on the total propagating field leading to a diffraction-limited focusing i.e. an effective optical lens effect with high numerical aperture. In addition, they have low sidelobe intensities, long depths of focus, and they have a low sensitivity with polarization. For pairs with inner wall distances smaller than about 1.2λ, the focusing phase modulation is accumulated during the propagation through the dielectric pair structure. In this work, we report only on the experimental demonstration for the case of larger wall separation to emphasize on the scattered wave effect on micro-focusing. A pair of parallel polymer lines (cylindrical lens), and a grid of polymer lines (square microlens array) with 2 μm-spacing were fabricated by two-photon induced polymerization. Their focal lengths are comparable to their separating distances, their spot-sizes are 0.37 μm and 0.28 μm at wavelength 530 nm, and their focusing efficiencies are 70% and 60%, respectively