Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailNon-adiabatic pulsations in delta Scuti stars
Moya, A.; Garrido, R.; Dupret, Marc-Antoine ULg

in Stellar Structure and Habitable Planet Finding (2004, January 01)

For delta Scuti stars, phase differences and amplitude ratios between the relative effective temperature variation and the relative radial displacement can be derived from multicolor photometric ... [more ▼]

For delta Scuti stars, phase differences and amplitude ratios between the relative effective temperature variation and the relative radial displacement can be derived from multicolor photometric observations. The same quantities can be also calculated from theoretical non-adiabatic pulsation models. We present here these theoretical results, which indicate that non-adiabatic quantities depend on the mixing length parameter alpha used to treat the convection in the standard Mixing Length Theory (MLT). This dependence can be used to test and to constrain, through multicolor observations, the way MLT describes convection in the outermost layers of the star. We will use the equilibrium models provided by the CESAM evolutionary code. The pulsational observables are calculated by using a non-adiabatic pulsation code developed by R. Garridon and A. Moya. In the evolutionary and pulsation codes, a complete reconstruction of the non-grey atmosphere (Kurucz models) is included. The interaction between pulsation and atmosphere, as described by Dupret et al. (2002), is also included in the code. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
See detailNon-adiabatic seismic study of the thin convective envelope of delta Scuti stars
Dupret, Marc-Antoine ULg; Grigahcène, A.; Garrido, R. et al

in IAU Colloq. 193: Variable Stars in the Local Group (2004, May 01)

For delta Sct stars, the theoretical predictions of a non-adiabatic pulsation code are very dependent on the characteristics of the thin convective envelope of the models (Balona and Evers 1999). The ... [more ▼]

For delta Sct stars, the theoretical predictions of a non-adiabatic pulsation code are very dependent on the characteristics of the thin convective envelope of the models (Balona and Evers 1999). The treatment of the non-adiabatic interaction between convection and pulsation also has a significant impact on the results, particularly near the red edge of the instability strip. The non-adiabatic theoretical predictions can be tested upon observations by comparing them to the amplitude ratios and phase differences as observed in different color passbands (Dupret et al. 2003). In the first part of this paper, we compare the results obtained by adopting different treatments of convection in the interior and atmosphere models: mixing-length theory (MLT) and full spectrum of turbulence (FST) (Canuto et al. 1996, CGM). In the second part, we examine the problem of the interaction between convection and pulsation and compare the mode stability obtained with and without including time-dependent convection in our non-adiabatic code. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Full Text
See detailNon-adiabatic seismic study of the triple system DG Leo
Grigahcène, A.; Suárez, J. C.; Dupret, Marc-Antoine ULg et al

in Tidal Evolution and Oscillations in Binary Stars (2005, November 01)

The interest in studying multiple systems comes from the fact that they give a good number of constraints on their components. From the multiplicity we have constraints on mass and age. Moreover, if one ... [more ▼]

The interest in studying multiple systems comes from the fact that they give a good number of constraints on their components. From the multiplicity we have constraints on mass and age. Moreover, if one or more components of the system show oscillating properties as the DG Leo triple system, additional constraints provided by seismology can be obtained once the modes are identified. In this work, we consider an equilibrium model of the DG Leo system constrained by its multiplicity properties, we attempt to check our new Time Depending Convection treatment on the modes identification of the DG Leo system. [less ▲]

Detailed reference viewed: 3 (0 ULg)
Full Text
Peer Reviewed
See detailNon-adiabatic theoretical observables in delta Scuti stars
Moya, A.; Garrido, R.; Dupret, Marc-Antoine ULg

in Astronomy and Astrophysics (2004), 414

Phase differences and amplitude ratios at different colour photometric bands are currently being used to discriminate pulsation modes to facilitate mode identification of kappa-driven non-radial pulsating ... [more ▼]

Phase differences and amplitude ratios at different colour photometric bands are currently being used to discriminate pulsation modes to facilitate mode identification of kappa-driven non-radial pulsating stars. In addition to physical inputs (e.g., mass, T_eff, etc.), these quantities depend on the non-adiabatic treatment of the atmosphere. This paper presents theoretical results concerning delta Scuti pulsating stars. The envelope of each of these stellar structures possesses a convection zone whose development is determined by various factors. An interacting pulsation-atmosphere physical treatment is introduced which supplies two basic non-adiabatic physical quantities: the relative effective temperature variation and the phase lag phi[SUP]T[/SUP], defined as the angle between effective temperature variation and radial displacement. These quantities can be used to derive the phase differences and amplitude ratios. Numerivalues for these quantities depend critically on the alpha MLT parameter used to calculate the convection in the envelope. The dependence on alpha was analyzed and it was found that the use of colour observations may be of considerable importance in testing the MLT. Finally, examples are given of how alpha introduces uncertainties in the theoretical predictions regarding phases and amplitudes of photometric variations in delta Scuti pulsating stars. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailNon-adiabatic wave packet dynamics for charge exchange processes in ion-atom collisions: application to C4+ + H
Vaeck, Nathalie; Desouter, Michèle ULg; Liévin, Jacques

in Journal of Physics : B Atomic Molecular & Optical Physics (1999), 32

Detailed reference viewed: 4 (0 ULg)
Peer Reviewed
See detailNon-alcoholic steatohepatitis.
Luyckx, Françoise ULg; Scheen, André ULg; Lefebvre, Pierre ULg

in Lancet (1999), 354(9186), 1298-9

Detailed reference viewed: 13 (1 ULg)
Peer Reviewed
See detailNon-alcoholic steatohepatitis: association with obesity and insulin resistance, and influence of weight loss.
Luyckx, Françoise ULg; Lefebvre, Pierre ULg; Scheen, André ULg

in Diabètes & Métabolism (2000), 26(2), 98-106

Non-alcoholic steatohepatitis (NASH) is a disease of emerging identity and importance, and is now considered as one of the commonest liver diseases in western countries. It is frequently associated with ... [more ▼]

Non-alcoholic steatohepatitis (NASH) is a disease of emerging identity and importance, and is now considered as one of the commonest liver diseases in western countries. It is frequently associated with severe obesity, especially abdominal adiposity, and is intimately related to various clinical and biological markers of the insulin resistance syndrome. Especially, both the prevalence and the severity of liver steatosis are related to male sex, body mass index, waist circumference, hyperinsulinaemia, hypertriglyceridaemia and impaired glucose tolerance or type 2 diabetes. A substantial weight loss following gastroplasty is accompanied by a marked reduction in the prevalence and the severity of the various biological abnormalities of the metabolic syndrome and, concomitantly, by an important regression of liver steatosis in most obese patients. However, in some patients, this rapid and drastic weight loss may result in a mild increase in inflammatory lesions (hepatitis), despite the regression of steatosis, which might result from the rapid mobilization of fatty acids or cytokines from adipose tissue, especially visceral fat. The intimate relationship between NASH and obesity leads to the concept that NASH may be considered as another disease of affluence, as is the insulin resistance syndrome and perhaps being part of it. [less ▲]

Detailed reference viewed: 33 (2 ULg)
Full Text
Peer Reviewed
See detailNON-ANTHOCYANIN POLYPHENOLS QUANTIFICATION IN EUTERPE OLERACEA FRUITS BY A UHPLC−LTQ-ORBITRAP MS METHOD
Dias, Aecio; Rozet, Eric ULg; Chataigné, G et al

Poster (2013, May)

High antioxidant and anti-inflammatory activities have been observed from non-anthocyanin polyphenols of E. oleracea fruits [1-2]. The aim of this work was to quantify major non-anthocyanin polyphenols by ... [more ▼]

High antioxidant and anti-inflammatory activities have been observed from non-anthocyanin polyphenols of E. oleracea fruits [1-2]. The aim of this work was to quantify major non-anthocyanin polyphenols by an accurate UHPLC−LTQ-Orbitrap MS method. Fruits were harvested in Pará state (Brazil), processed to pulp and lyophilised. 0.5g of dry pulp powder was defatted by sonication with petroleum ether. The residue was then extracted five times with 5mL MeOH each time for 30 min (optimized conditions giving recovery rates > 90%). The extract was evaporated to dryness with a RapidVap® evaporator at 35°C. Solubilization of the dried extract was realised using 40% MeOH. For the UHPLC quantification, a HSS C18 column (1.8µm) was used with a gradient elution of MeOH and H2O both with 0.1% HCOOH and the ionisation source (ESI) was operated in NI mode. 26 compounds were identified, among them 7 identified for the first time in this fruit. Total error and accuracy profiles were used as validation criteria. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness, repeatability, intermediate precision, selectivity, response function, linearity and LOD/LOQ for 12 non-anthocyanin phenolic compounds were evaluated and the quantification method validated. [1] J. Kang et al., Food Chem. 122 (2010) 610–617. [2] J. Kang et al., Food Chem. 128 (2011) 152–157. [less ▲]

Detailed reference viewed: 49 (4 ULg)
Full Text
Peer Reviewed
See detailNon-aqueous capillary electrophoretic enantioseparation of N-derivatized amino acids using cinchona alkaloids and derivatives as chiral counter-ions.
Piette, Véronique; Fillet, Marianne ULg; Lindner, W. et al

in Journal of Chromatography. A (2000), 875(1-2), 353-60

A non-aqueous capillary electrophoretic method developed with quinine and tert.-butyl carbamoylated quinine as chiral selectors for the enantioseparation of N-protected amino acids was applied to the ... [more ▼]

A non-aqueous capillary electrophoretic method developed with quinine and tert.-butyl carbamoylated quinine as chiral selectors for the enantioseparation of N-protected amino acids was applied to the investigation of other quinine derivatives as chiral additives. The optimum composition of the background electrolyte was found to be 12.5 mM ammonia, 100 mM octanoic acid and 10 mM chiral selector in an ethanol-methanol (60:40, v/v) mixture. Under these conditions, a series of chiral acids, as various benzoyl, 3,5-dinitrobenzoyl and 3,5-dinitrobenzyloxycarbonyl amino acid derivatives were investigated with regards to selectand-selector relationships and enantioselectivity employing quinine, quinidine, cinchonine, cinchonidine, tert.-butyl carbamoylated quinine, tert.-butyl carbamoylated quinidine, dinitrophenyl carbamoylated quinine and cyclohexyl carbamoylated quinine as chiral selector. [less ▲]

Detailed reference viewed: 19 (2 ULg)
Full Text
Peer Reviewed
See detailA non-canonical caleosin from Arabidopsis efficiently epoxidizes physiological unsaturated fatty acids with complete stereoselectivity
Bléé, Elizabeth; Flenet, Martine; Boachon, Benoit et al

in FEBS Journal (2012), 279

Detailed reference viewed: 14 (3 ULg)
See detailNon-classical Radiation from Two Atoms and Quantum Search Algorithms
Agarwal, G. S.; von Zanthier, J.; Bastin, Thierry ULg

Conference (2005)

Detailed reference viewed: 6 (1 ULg)
Full Text
Peer Reviewed
See detailA Non-Cofactor Role of Thiamine Derivatives in Excitable Cells?
Bettendorff, Lucien ULg

in Archives of Physiology & Biochemistry (1996), 104(6), 745-751

Thiamine diphosphate (TDP) is an important cofactor of pyruvate (PDH) and alpha-ketoglutarate (KGDH) dehydrogenases and transketolase. Thiamine deficiency leads to reversible and irreversible brain ... [more ▼]

Thiamine diphosphate (TDP) is an important cofactor of pyruvate (PDH) and alpha-ketoglutarate (KGDH) dehydrogenases and transketolase. Thiamine deficiency leads to reversible and irreversible brain lesions due to impaired oxidative metabolism. A specific non-cofactor role for thiamine has also been proposed in excitable cells and thiamine triphosphate (TTP) might be involved in the regulation of ion channels. Thiamine is taken up by neuroblastoma cells through a high affinity transporter. Inside the cells, it is rapidly phosphorylated to TDP. This high turnover TDP pool is the precursor for TTP. Most of the TDP however has a low turnover and is associated with PDH and KGDH in mitochondria. In excised inside-out patches from neuroblastoma cells, TTP, at a concentration of 1 microM, activates chloride channels of large unitary conductance, the so-called maxi-Cl- channels. These channels are inhibited by oxythiamine from the outide. In addition to the role of TTP in the regulation of chloride channels, thiamine itself, or a presently unknown analog, may have trophic effects on neuronal cells. [less ▲]

Detailed reference viewed: 24 (9 ULg)
Full Text
See detailNon-competition concerns under the ECMR - An overview
Petit, Nicolas ULg

in Concurrences : Revue des Droits de la Concurrence (2008), 4-2008

This article lists the EC merger cases where noncompetition concerns were raised (industrial policy, social concerns, personal data protection etc.). It summarizes the issues raised by non-competition ... [more ▼]

This article lists the EC merger cases where noncompetition concerns were raised (industrial policy, social concerns, personal data protection etc.). It summarizes the issues raised by non-competition concerns in the ECMR. [less ▲]

Detailed reference viewed: 89 (3 ULg)
Full Text
Peer Reviewed
See detailNon-conforming element for accurate modelling of MEMS
Rochus, Véronique ULg; Rixen, Daniel J.; Golinval, Jean-Claude ULg

in Finite Elements in Analysis & Design (2007), 43(10), 749-756

In this work different modelling techniques are investigated to simulate the dynamic behaviour of slender structures on which electrostatic forces are acting. In particular, non-conforming elements are ... [more ▼]

In this work different modelling techniques are investigated to simulate the dynamic behaviour of slender structures on which electrostatic forces are acting. In particular, non-conforming elements are tested to model micro- mechanical devices (or MEMS) having a very large aspect ratio. These elements are constructed on linear shape functions enriched by internal second-order polynomials. As a consequence the element compatibility is not exactly satisfied, but such elements can efficiently model beam- or shell-like structures with a small number of degrees of freedom. The advantage of non-conforming elements compared to shell or beam elements is that they are volume elements and can therefore easily be combined with other volume finite elements. For micro-mechanical systems the structure must be coupled to the electrostatic domain with the so-called electro-mechanical elements that solve for the electrostatic potential and generate the electrostatic forces. This paper shows that constructing coupled electro-mechanical models for high aspect ratio systems is then greatly simplified when non-conforming finite elements are used. The theory is presented for small deformations and also for large displacements where geometric non-linearities must be accounted for. The elements proposed in this paper are based on non-conforming formulations published earlier. The efficiency of the non-conforming approach combined with specific electro-mechanical elements is highlighted in the analysis of two simple MEMS for which the pull-in voltage is computed. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 29 (5 ULg)
See detailNon-conventional Political Participation as an outcome of Discrimination Feeling
Gavray, Claire ULg; Born, Michel ULg

Scientific conference (2012, April 17)

Detailed reference viewed: 23 (3 ULg)
Full Text
Peer Reviewed
See detailNon-conventional.illegal political participation of male and female youths
Gavray, Claire ULg; Fournier; Born, Michel ULg

in Human Affairs (2012), 22

Detailed reference viewed: 30 (7 ULg)
Full Text
Peer Reviewed
See detailNon-confined jet-slot-cavity oscillator: flow-acoustic interaction modeling
Glesser, Martin; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2006, May)

Disturbing whistling due to self-sustained oscillations can be produced in a wide variety of geometries where a sheared subsonic flow impinges on a downstream obstacle. When those self-sustained ... [more ▼]

Disturbing whistling due to self-sustained oscillations can be produced in a wide variety of geometries where a sheared subsonic flow impinges on a downstream obstacle. When those self-sustained oscillations are coupled with an acoustic resonator, the acoustic production can reach dramatically high levels. The configuration known as jet-slot oscillator is studied in the particular case where the resonator is the flow-supply duct and the source region is unconfined. This sound production is due to flow-acoustic interactions and can be modeled by using the vortex-sound theory. It allows one to express the acoustic power generated by the interaction between the acoustic, velocity, and vorticity fields. They are obtained separately by using rather simple models together with experimental input data. The vorticity field is modeled with the assumption that the shear layer is rectilinear and the vorticity is only concentrated on discrete vortex-points convected at constant velocity. The vorticity being non null only in the shear layer, the velocity field is calculated only in this region where it is equal to the vortices convection speed. The source region dimensions being small compared to the acoustic wavelength, this field is considered, in harmonic regime, as a sinusoidal temporal fluctuation of a potential field. This field can be taken as resulting from the flow produced by the radiation of the flow supply duct's acoustic resonance. It is obtained by solving the Poisson equation in a simplified geometry obtained by Schwarz-Christoffel mapping. The configuration studied here presents some specific problems which must be addressed to correctly model its sound production. Experimentations are used to specify the missing parameters. The major one is the synchronisation between the vorticity field and the acoustic field which governs the way that the vortices interact with the resonant acoustic field. At last, comparison between experimental data and modeling results permits to validate the study, in terms of emitted frequency. Further developments of the model will allow to predict the emitted sound level. [less ▲]

Detailed reference viewed: 34 (0 ULg)
Full Text
Peer Reviewed
See detailThe non-core regions of human lysozyme amyloid fibrils influence cytotoxicity.
Mossuto, Maria F; Dhulesia, Anne; Devlin, Glyn et al

in Journal of Molecular Biology (2010), 402(5), 783-96

Identifying the cause of the cytotoxicity of species populated during amyloid formation is crucial to understand the molecular basis of protein deposition diseases. We have examined different types of ... [more ▼]

Identifying the cause of the cytotoxicity of species populated during amyloid formation is crucial to understand the molecular basis of protein deposition diseases. We have examined different types of aggregates formed by lysozyme, a protein found as fibrillar deposits in patients with familial systemic amyloidosis, by infrared spectroscopy, transmission electron microscopy, and depolymerization experiments, and analyzed how they affect cell viability. We have characterized two types of human lysozyme amyloid structures formed in vitro that differ in morphology, molecular structure, stability, and size of the cross-beta core. Of particular interest is that the fibrils with a smaller core generate a significant cytotoxic effect. These findings indicate that protein aggregation can give rise to species with different degree of cytotoxicity due to intrinsic differences in their physicochemical properties. [less ▲]

Detailed reference viewed: 26 (8 ULg)
Full Text
Peer Reviewed
See detailA non-cytosolic protein of Trypanosoma evansi induces CD45-dependent lymphocyte death.
Antoine-Moussiaux, Nicolas ULg; Cornet, Anne ULg; Cornet, François ULg et al

in PLoS ONE (2009), 4(5), 5728

In a recent study dealing with a mouse model of Trypanosoma evansi-associated disease, a remarkable synchrony between the parasitaemia peak and the white-blood-cell count nadir was noticed. The present ... [more ▼]

In a recent study dealing with a mouse model of Trypanosoma evansi-associated disease, a remarkable synchrony between the parasitaemia peak and the white-blood-cell count nadir was noticed. The present study was designed to establish whether there is a direct causal link between the parasite load during its exponential phase of growth and the disappearance of peripheral blood leukocytes. In vitro experiments performed with trypanosomes and purified peripheral blood mononucleated cells revealed the existence of a lymphotoxin embedded in the T. evansi membrane: a protein sensitive to serine proteases, with a molecular mass of less than 30 kDa. Lymphocytes death induced by this protein was found to depend on the intervention of a lymphocytic protein tyrosine phosphatase. When lymphocytes were exposed to increasing quantities of a monoclonal antibody raised against the extracellular portion of CD45, a transmembrane protein tyrosine phosphatase covering over 10% of the lymphocyte surface, T. evansi membrane extracts showed a dose-dependent decrease in cytotoxicity. As the regulatory functions of CD45 concern not only the fate of lymphocytes but also the activation threshold of the TCR-dependent signal and the amplitude and nature of cytokinic effects, this demonstration of its involvement in T. evansi-dependent lymphotoxicity suggests that T. evansi might manipulate, via CD45, the host's cytokinic and adaptive responses. [less ▲]

Detailed reference viewed: 74 (29 ULg)