2,497 research outputs found

    Polyphenol alkyl ester inhibits membrane cholesterol domain formation through an antioxidant mechanism based, in nonlinear fashion, on chain length

    Get PDF
    Under conditions of oxidative stress, cholesterol aggregates into discrete membrane bilayer domains that precipitate the formation of extracellular crystals, a hallmark feature of the advanced atheroma in cardiovascular disease. Molecular intervention using membrane-directed antioxidants, such as polyphenolic esters, alkylated to increase their lipophilicity and bioavailability, may reduce cholesterol domain formation and associated pathology. In this study, we tested the effects of rosmarinic acid (R0) and rosmarinic esters, with alkyl chain lengths ranging from 4 to 16 carbons (R4-R16), on membrane lipid oxidation and cholesterol domain formation. Model membranes were prepared as binary mixtures of dilinoleoylphosphatidylcholine and cholesterol (at a cholesterol-to-phospholipid mole ratio of 0.6:1), in the absence or presence of each of the various rosmarinic compounds, and exposed to oxidative conditions for up to 72 hr. Changes in lipid hydroperoxide (LOOH) and cholesterol domain formation were measured using iodometric and small angle x-ray diffraction approaches, respectively. Rosmarinic acid and the various esters were observed to have differential effects on LOOH formation based on alkyl chain length. R8 had the greatest antioxidant effect, reducing LOOH levels by 60 ± 18% as compared to vehicle. R8 also inhibited cholesterol domain formation. By contrast, R0 and R16 failed to inhibit LOOH formation (6 ± 19% reduction, 5 ± 13% increase compared to vehicle, respectively), resulting in cholesterol domain formation. These data indicate that the membrane antioxidant potential of rosmarinic acid esters is dependent, in a nonlinear manner, on alkyl chain length. The mechanism for this effect is attributed to the influence of alkyl chain length on the optimal depth of the polyphenols into the lipid bilayer. These findings provide insight into novel atheroprotective benefits of polyphenol esters that are dependent on their membrane location

    Advanced microwave radiometer antenna system study

    Get PDF
    The practicability of a multi-frequency antenna for spaceborne microwave radiometers was considered in detail. The program consisted of a comparative study of various antenna systems, both mechanically and electronically scanned, in relation to specified design goals and desired system performance. The study involved several distinct tasks: definition of candidate antennas that are lightweight and that, at the specified frequencies of 5, 10, 18, 22, and 36 GHz, can provide conical scanning, dual linear polarization, and simultaneous multiple frequency operation; examination of various feed systems and phase-shifting techniques; detailed analysis of several key performance parameters such as beam efficiency, sidelobe level, and antenna beam footprint size; and conception of an antenna/feed system that could meet the design goals. Candidate antennas examined include phased arrays, lenses, and optical reflector systems. Mechanical, electrical, and performance characteristics of the various systems were tabulated for ease of comparison

    Less is more ? The Commission proposal on access to EU documents and the proper limits of transparency

    Get PDF
    Transparency is now seen as a key tool of democratic governance. The European Union's commitment to transparency is now at the centre of a crucial debate between the Commission and the Parliament on the future of citizen's right of access to information. This article presents the main characteristics of the current regime and questions the pertinence of the proposed changes in light of the international drive at modernising access to information laws and the attempt at identifying the ̳proper limits of transparency'. The questions raised range from the identification of what can be accessed to the definition of exemption and the protection of competing interests

    Description sensorielle de la carotte - recherche et mise au point d'une méthodologie

    Get PDF
    En évaluation sensorielle, la description des caractéristiques organoleptiques d\u27un produit par la méthode de profil sensoriel demande, dans un premier temps, de déterminer les descripteurs qui vont être pertinents dans la caractérisation du produit. Cet article présente les différentes étapes de mise en place d\u27une liste de descripteurs appliquée à la carotte. La carotte étant un produit consommé cru ou cuit et sous différentes formes, trois modes d\u27usage (carotte crue râpée, cuite entière, crue en rondelle...) vont être comparés, afin de déterminer quel est l\u27apport de chacune des méthodes dans la description du produit

    Alignment dependent enhancement of the photo-electron cutoff for multi-photon ionization of molecules

    Get PDF
    The multiphoton ionization rate of molecules depends on the alignment of the molecular axis with respect to the ionizing laser polarization. By studying molecular frame photo-electron angular distributions from N2_2, O2_2 and benzene, we illustrate how the angle-dependent ionization rate affects the photo-electron cutoff energy. We find alignment can enhance the high energy cutoff of the photo-electron spectrum when probing along a nodal plane or when ionization is otherwise suppressed. This is supported by calculations using a tunneling model with a single ion state.Comment: 4 pages, 4 figure

    French consumer preferences reveal a potential for segmentation in carrot

    Get PDF
    Gustatory differentiation is one possible means of segmentation. Consumer preferences of carrot were studied within the framework of the CosiVeg project. The characteristics of batches offered for consumer assessment enables their preferences to be evaluated. In preparation for a hedonic test of raw grated carrots that was carried out in autumn 2011, the carrot sensory space was studied in 2010 using 48 batches that were evaluated using quantative descriptive sensory analysis. The cultivars were representative of different types, Nantais, Imperator, Flakkee, coloured carrots and genetic resources. . Significant differences were observed for all criteria, allowing varieties to be grouped based on their sensory characteristics. Texture, flavor and aroma contribute to the “identity” of carrots. Overall aroma is correlated with perceptions of bitterness, sharpness and chemical aroma. Fourteen orange carrot varieties were selected for sowing in 2011. In 2010, although maximum scores were obtained for pungent and bitter attributes, this was not the case in 2011. In spite of this, the selected batches allowed the different profiles of the sensory characteristics of the carrots to be determined. Ten batches of carrot that represented a wide range of variability were tasted by a trained panel as well as a consumer panel; the product was presented as raw grated carrot. The sensory measurements obtained were used to map preferences, underlining preferences for a carrot that is juicy, aromatic and sweet. However bitter and chemical flavour carrots were not appreciated. Three types of consumer exist each having different expectations in terms of quality. Almost 20 % of people questioned are looking for a high quality product, for 33 % of consumers carrots are a staple food and they have no specific expectations and 48 % are satisfied with the current product but are potentially interested by a product that would distinguish itself as regards to quality. It means that segmentation with a high gustatory quality will be of interest for one consumer for 5

    Qualité organoleptique de la carotte : variabilité des critères sensoriels selon le type variétal

    Get PDF
    La différenciation gustative est une voie possible de segmentation. L\u27étude a porté sur la variabilité des critères sensoriels dans le matériel végétal. Trente-trois varié - tés des types Nantais, Imperator, Flakkee, de carottes de couleur et de ressources génétiques ont été caractérisées en analyse sensorielle descriptive quantitative et par des mesures physico-chimiques. Des différences significatives pour tous les critères existent et permettent de regrouper les variétés sur la base de leurs caractéristiques sensorielles. Texture, saveur et arôme contribuent à la typicité de la carotte ; l\u27arôme global est corrélé aux perceptions d\u27amer, de piquant et d\u27arôme chimique. La mesure des sucres ne permet pas d\u27évaluer la perception en bouche du sucre du fait de l\u27influence du potentiel d\u27amertume
    corecore