Effet des conditions d'apprentissage sur le pouvoir discriminant de sujets effectuant le profil sensoriel de jus d'orange

1996

National audience

Mesure des arômes

1996

National audience

Effect of Peripheral Substitution and Extended Conjugation on the Redox Potentials of Nickel Porphycenes

1996

Eight different nickel porphycenes bearing substituents on the pyrrole β and/or ethylenic carbon positions of the macrocycle were investigated as to their redox properties in benzonitrile containin...

NbxRu6-xTe8, New Chevrel-Type Clusters Containing Niobium and Ruthenium,

1996

Phases of composition Nb(x)()Ru(6)(-)(x)()Te(8) were prepared by reacting stoichiometric mixtures of the elements at high temperature in evacuated silica ampules. The structure of Nb(3.33)Ru(2.67)Te(8) was refined from X-ray powder data using the Rietveld method. Nb(3.33)Ru(2.67)Te(8) crystallizes isotypic with Mo(6)Q(8) (Q = S, Se, Te) in the rhombohedral space group Rthremacr; with the hexagonal lattice parameters a = 10.34106(5) Å, c = 11.47953(7) Å, and Z = 3. Its structure consists of M(6)Te(8) mixed-metal clusters (M = Nb, Ru) which are connected by intercluster M-Te bonds to form a three-dimensional network. Metal-metal bonding in these phases is analyzed in terms of Pauling bond ord…

New Insights into the Coupling of $\eta $ and $f_1$ Mesons to the Nucleon

1996

We show that the contact couplings of neutral pseudoscalar and axial mesons to the nucleon are proportional to $\Delta s$, the fraction of nucleon spin carried by the strange quark sea, and thus are strongly suppressed relative to the couplings of charged mesons to the nucleon. On the other side, recent high accuracy data on $\eta $ photoproduction at threshold reveal the need for non--negligibile $\eta NN$ vertices, while fitting $\bar N N$ phase shifts by means of effective meson exchange potentials requires a substantial presence of $f_1$ mesons there. We here advocate the idea to attribute the couplings of neutral pseudoscalar and axial vector mesons to effective triangular diagrams con…

Unitary Approach to Vibrational Spectra of Polyatomic Molecules: Generalized Infrared Intensity Model.

1996

Alternative assay procedures for cytokines and soluble receptors of the IL-6 family.

1996

Human hepatoma cells (HepG2 cells) were transfected with expression vectors for human IL-6 (hIL-6) and rat IL-6R (rIL-6-R). The cell lines were used for testing the biological activity of different IL-6 species, soluble hIL-6R (shIL-6R) and some members of the IL-6 cytokine family by means of an ELISA procedure. The assay is based on induction of the gene expression of the acute phase protein haptoglobin in hepatoma cells and provides an alternative bioassay taking advantage of the hepatocyte stimulatory activity of IL-6 (as opposed to the B9 proliferative assay). A dose-response experiment with IL-6 showed that half-maximal stimulation was achieved with approx. 5 ng/ml of hIL-6 in HepG2 ce…

Lymphoproliferative disorders in Sotos syndrome: Observation of two cases

1996

Sotos syndrome is included among the overgrowth disorders, most of which have an increased risk of neoplasms. Sotos syndrome does not appear to be related to a specific tumor type, but rather to the development of solid tumors of ectodermal or mesodermal origin in general. We report on two Sotos syndrome patients who developed a non-Hodgkin lymphoma and an acute lymphoblastic leukaemia, respectively. Our experience suggests that there may exist a high frequency of lymphoproliferative disorders in Sotos syndrome, and points out the importance of a long-term follow-up of Sotos syndrome patients, to detect a possible neoplastic evolution. ©1996 Wiley-Liss, Inc.

Multiplicity of Reaction Pathways in the Processes of Oxygen Transfer to Secondary Amines by Mo(VI) and W(VI) Peroxo Complexes.

1996

Oxidation of N,N-benzylmethylamine, N,N-benzylisopropylamine, and N,N-benzyl-tert-butylamine by both anionic and neutral Mo(VI) and W(VI) oxodiperoxo complexes yields the corresponding nitrones quantitatively. The oxidation reactions employing anionic oxidants were performed in CHCl(3) and follow second-order kinetics, first order with respect to the amine and to the oxidant. The data were rationalized on the basis of a rate-determining nucleophilic attack of the amine onto the peroxide oxygen of the oxidant, with a transition state in which N-O bond formation and O-O bond cleavage occur in a concerted way (electrophilic oxygen transfer mechanism). This attack yields the corresponding hydro…

Représentativité des extraits d'arômes réalisés au laboratoire

1996

44 ref.; National audience

En brazos de la mujer madura... (Acercamiento a la tipología de la mujer madura en Francia, siglos XVII-XVIII: de la realidad a la ficción).

1996

Cuando Candido, el heroe que da su nombre al cuento filosofico de Voltaire, vuelve a encontrar a su amada Cunegonda tras tormentosas tribulaciones por esos mundos de Dios, elle ya no es la joven de 17 anos, fresca, maciza y apetitosa. Aquella por la que Candido merecio su expulsion del edenico castillo de Westfalia con una patada en el trasero se ha convertido en una mujer «triste, con ojos roncos, garganta seca, mejillas arrugadas, brazos enrojecidos y escamados», en suma todo lo que puede provocar la repulsa del personaje que no puede evitar sentirse sobrecogido de horror (asi lo dice el cuento). Claro que el tiempo ha pasado, y no en vano para Cunegonda, aunque no sepamos cuanto con exac…

A quantitative test of the mode-coupling theory of the ideal glass transition for a binary Lennard-Jones system

1996

Using a molecular dynamics computer simulation we determine the temperature dependence of the partial structure factors for a binary Lennard-Jones system. These structure factors are used as input data to solve numerically the wave-vector dependent mode-coupling equations in the long time limit. Using the so determined solutions, we compare the predictions of mode-coupling theory (MCT) with the results of a previously done molecular dynamics computer simulation [Phys. Rev. E 51, 4626 (1995), ibid. 52, 4134 (1995)]. From this comparison we conclude that MCT gives a fair estimate of the critical coupling constant, a good estimate of the exponent parameter, predicts the wave-vector dependence …

Crystal size distribution in Jurassic Ferrar flows and sills (Victoria Land, Antarctica): evidence for processes of cooling, nucleation, and crystall…

1996

Jurassic Ferrar rocks in Victoria Land (Antarctica) occur predominantly as basaltic or andesitic flows and sills. Both show characteristic petrographical and chemical variations, which can be related to in-situ differentiation processes. Such characteristics have been investigated at one flow (“Colonnade flow”) and one sill (“Thumb Point sill”) in the Prince Albert Mountains (Central Victoria Land) based on a statistical grain size analysis and the application of the crystal size distribution theory. A third magma body (“HiTi-unit”), which in previous literature was described as a flow, does not show clear similarities to either the flow or sill. Sill and flow are in-situ differentiated wit…

Impaired HLA-class-I stability in a sarcoma cell line which stimulates exclusively HLA-class-II-restricted autologous T cells

1996

Defects in the generation and transport of antigenic peptides within tumor cells will lead to the expression of unstable HLA-class-I molecules on the cell surface. These defects will allow tumor cells to escape an MHC-class-I-restricted T-cell response. Recently, we described an exclusively HLA-class-II-restricted autologous T-cell response against a human sarcoma cell line MZ-MES-1 in vitro. Here, we show that surface HLA-class-I molecules of MZ-MES-1 cells are unstable at physiological temperature. HLA-class-I surface expression of MZ-MES-1 cells could be strongly enhanced by culture at low temperature in contrast to various other cell lines analyzed in parallel. Furthermore, culture at l…

Subcellular distribution of ras in human and murine fibroblasts.

1996

Abstract Ras proteins play a significant role in signal transduction in response to growth factors and in cell transformation. To be active, ras has to be translocated to the cell membrane. Since subcellular distribution has been mainly studied in vector-transformed cells which highly express ras proteins, and it has been difficult to detect ras in cells expressing the protein at physiological levels, we studied subcellular distribution in human and murine fibroblasts. Here we show for the first time that a significant amount of ras is associated with the membrane skeleton and the cytoskeleton.

Detection of Interstitial Oxygen Molecules in SiO2Glass by a Direct Photoexcitation of the Infrared Luminescence of SingletO2

1996

The presence of interstitial oxygen molecules in glassy ${\mathrm{SiO}}_{2}$ has been demonstrated directly by 1064.1 nm $({\ensuremath{\nu}}^{\ensuremath{'}\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)\ensuremath{\rightarrow}({\ensuremath{\nu}}^{\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1)$ excitation of the forbidden ${O}_{2}$ molecule $^{1}\ensuremath{\Delta}_{g}({\ensuremath{\nu}}^{\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)\ensuremath{\rightarrow}^{3}\ensuremath{\Sigma}_{g}({\ensuremath{\nu}}^{\ensuremath{'}\ensuremath{'}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0)$ luminescence transition at 1272 nm in S…

Hartree - Fock simulation of the Ag/MgO interface structure

1996

The atomic and electronic structure of the Ag/MgO interface are calculated using an ab initio Hartree - Fock computer code and a supercell model of a silver monolayer atop three layers of MgO substrate. The band structure, electronic density distribution and densities of states are analysed in detail for isolated and interacting slabs of a metal and MgO. The energetically most favoured adsorption position for Ag atoms is found to be above the O atoms, with the binding energy of 0.20 eV and the equilibrium Ag - O distance of 2.64 A. Neither appreciable charge transfer in the interfacial region, nor considerable population of bonds between the silver monolayer and the insulating substrate tak…

Applicability Of The Hauser-Feshbach Approach For The Determination of Astrophysical Reaction Rates

1996

Nuclear Astrophysics requires the knowledge of reaction rates over a wide range of nuclei and temperatures. In recent calculations the nuclear level density - as an important ingredient to the statistical model (Hauser-Feshbach) - has shown the highest uncertainties. In a back-shifted Fermi-gas formalism utilizing an energy-dependent level density parameter and employing microscopic corrections from a recent FRDM mass formula, we obtain a highly improved fit to experimental level densities. The resulting level density is used for determining criteria for the applicability of the statistical model on neutron-induced reactions.

Kicked neutron stars and microlensing

1996

Due to the large kick velocities with which neutron stars are born in supernovae explosions, their spatial distribution is more extended than that of their progenitor stars. The large scale height of the neutron stars above the disk plane makes them potential candidates for microlensing of stars in the Large Magellanic Cloud. Adopting for the distribution of kicks the measured velocities of young pulsars, we obtain a microlensing optical depth of $\tau \sim 2 N_{10} \times 10^{-8}$ (where $N_{10}$ is the total number of neutron stars born in the disk in units of $10^{10}$). The event duration distribution has the interesting property of being peaked at $T \sim 60$--80 d, but for the rates t…

Coherent pion production in neutrino nucleus collision in the 1 GeV region

1996

We calculate cross sections for coherent pion production in nuclei induced by neutrinos and antineutrinos of the electron and muon type. The analogies and differences between this process and the related ones of coherent pion production induced by photons, or the (p,n) and $(^3 He, t)$ reactions are discussed. The process is one of the several ones occurring for intermediate energy neutrinos, to be considered when detecting atmospheric neutrinos. For this purpose the results shown here can be easily extrapolated to other energies and other nuclei.

Cationisation des esters de coenzyme A dans une matrice basique en LSIMS

1996

National audience

Calculation of phase diagrams not requiring the derivatives of the Gibbs energy for multinary mixtures

1996

A method for the calculation of phase diagrams (tie lines and binodal, spinodal, critical points and their stability) based exclusively on the Gibbs energy of mixing with no need of its derivatives with respect to the composition variables is extended to multinary mixtures for any number of components. The mathematical description of the (K-1)-dimensional phase diagram of a K-component mixture is presented. The method is demonstrated for a quinternary blend of five polymers exhibiting a closed miscibility gap; all binary, ternary and quaternary subsystems are completely miscible. The phase separation in the quinternary system is caused by very favorable interactions in the ternary subsystem…

Simultaneous Determination of Adrenaline and Noradrenaline by First Derivative Spectrophotometry in a Fia Assembly

1996

Abstract This article deals with the design of an unsegmented-flow injection manifold for the simultaneous determination of adrenaline and noradrenaline two structurally related compounds with overlapping spectra. An FIA manifold is proposed for the simultaneous determination in which the sample solution is directly injected into a carrier-reagent stream of aqueous NaOH. The selected wavelengths (first derivative) were 394 and 342 nm, for noradrenaline and adrenaline, respectively with an integration time of 0.4 s. The calibration graphs are linear over the range 2.0–30 ppm for both drugs. The method is applied to different synthetic mixtures of both drugs.

A theoretical determination of the electronic spectrum of Methylenecyclopropene

1996

The vertical electronic spectrum of methylenecyclopropene, the prototype of the nonalternant hydrocarbons known as fulvenes, has been studied using multiconfigurational second-order perturbation theory. The calculations comprise three valence states and the 3s, 3p, and 3d members of the Rydberg series converging to the first π ionization limit. Vertical excitation energies to three valence states are found at 4.13, 6.12, and 6.82 eV. The second of them corresponds to an excitation from the highest occupied σ orbital to a π* orbital, while the other two are π → π* excitations. The third transition gives rise to the most intense feature in the electronic spectrum. The results are rationalized…

Langmuir films and Langmuir-Blodgett multilayers incorporating mechanically-threaded molecules-pseudorotaxanes

1996

This paper describes the synthesis of a π-electron rich aromatic lipid containing a polyether thread intercepted by a 1,5-dioxynaphthalene moiety. The terminus of one end of the polyether is a methoxyl group and the other a glycerol unit linked via the 2-oxo position, while the 1,3-oxo functions are covalently attached to octadecyl chains. This compound, when cospread at the air-water interface with the tetracationic cyclophane, cyclobis(paraquat-p-phenylene), and the phospholipid, dimyristoylphosphatidic acid, as its monoanion, forms self-assembled pseudorotaxanes which are self-organized into a two-dimensional supramolecular array at the interface. The electrostatic interactions between t…

About entangled networks of worm-like micelles: a rejected hypothesis

1996

We report new results from small-angle neutron scattering on d(1 2)-cyclohexane/lecithin/water micellar solutions performed as a function of the water content (w(o)), temperature (T) and dispersed phase volume fraction (phi). The data from dilute samples are interpretable in terms of the existence of giant cylindrical reverse micelles and are well fit with a core-shell model (that provides the micelle structure and dimensions) with values of 28 and 45 Angstrom for the inner core and the outer shell radii, almost independent on temperature and concentration. Such a result could appear consistent with the current idea that worm-like micelles are living polymers. On the contrary, the appearanc…

1H NMR spectra of Ph2SbX, PhSbX2, and Ph3SbX2 (XCl, Br, I); 121Sb Mössbauer spectra of PhSbX2 and crystal structure of Ph2SbI1

1996

1H NMR spectroscopic data of Ph2SbX, PhSbX2, and Ph3SbX2 (XCl, Br, I) have been determined by iterative simulation. 121Sb Mossbauer spectra of PhSbX2 (XCl, Br, I) have been measured. The synthesis of Ph2SbI is achieved by reaction of Ph2SbCl with NaI in ethanol. The crystal structure of Ph2SbI consists of molecules with pyramidal C2SbI units.

Der Satz von Tits für PGL2(R), R ein kommutativer Ring vom stabilen Rang 2

1996

Certain permutation groups on sets with distance relation are characterized as groups of projectivities PGL2(R) on the projective line over a commutative ring R of stable rank 2, thus generalizing a classical result of Tits where R is a field.

Group-Theoretic analysis of the mixing angle in the electroweak gauge group

1996

In this paper the authors provide strong mathematical support for the idea that the experimentally measured magnitude 1 - M{sub W}{sup 2}/M{sub Z}{sup 2} associated with sin{sup 2}{theta}{sub w} in the standard model of electroweak interactions cannot be simultaneously identified with the squared quotient of the electric charge by the SU(2) charge, e{sup 2}/g{sup 2}. In fact, the natural, mathematical requirement that the Weinberg rotation between the gauge fields associated with the third component of the {open_quotes}weak isospin{close_quotes} (T{sub 3}) and the hypercharge (Y) proceeds from a global Lie-group homomorphism of the SU(2) {circle_times} U(1){sub y} gauge group in some locall…

Chemical variations in clay minerals of the Archaean Barberton Greenstone Belt (South Africa)

1996

Abstract Four rock profiles of shales, carbonates and greywacke-type sediments were sampled from the mafic compositional influenced sedimentary Fig Tree Group and from overlying, more felsic related, sedimentary Moodies Group of the Archaean Barberton Greenstone Belt in South Africa. Clay separates of forty sedimentary rocks were examined by XRD and SEM to study the mineralogical, chemical and morphological variations of the constitutive illite and chlorite. The clay minerals showed a significant K-enrichment in the illites and Mg- and Fe-depletions in the chlorites upwards the stratigraphic sequence. Three independent parameters influenced these variations: (1) a change in the origin of th…

Temperature-dependent phase transitions in water-oil-surfactant mixtures: Experiment and theory

1996

We investigate temperature induced phase transitions in mixtures of water, oil, and a nonionic surfactant. By microcalorimetric measurements it is shown that the droplet-lamellar transition shows hysteresis so that it is strongly first order. The position of this transition and of the emulsification boundary are quantitatively described by an interfacial model which considers solely the temperature dependence of the spontaneous curvature. There is no fit parameter in the model. Remarkably, the positions of both boundaries do not depend on the bending moduli. \textcopyright{} 1996 The American Physical Society.

Phase separation of blends of polydisperse polymers: Comparison between experiment and theory for the system poly(dimethylsiloxane)/poly(ethylmethyls…

1996

Cloud point curves were measured turbidimetrically for blends (upper critical solution temperatures ; UCSTs) of poly(ethylmethylsiloxane) (PEMS) and four different samples of poly(dimethylsiloxane) (PDMS) ; the weight average molar masses in kg/mol are 31.2 for PEMS and 10.4, 15.5, 18.1 and 24.0 for PDMS ; all components have polydispersity indices D (= M w /M n ) within the range from 1.82 to 2.67. Corresponding calculations on the basis of the Flory-Huggins theory (three adjustable parameters) account for the polydispersity; molecular weight distributions are represented by the generalized Schulz-Flory equation. Calculated cloud point curves agree very well with those measured, if individ…

An approach to predictive testing of contact sensitizers in vitro by monitoring their influence on endocytotic mechanisms.

1996

Endocytotic activation of epidermal Langerhans cells (LC) by immunogenic haptens is an early event during development of allergic contact dermatitis. In this work a fast and objective flow-cytometric assay for predictive in vitro testing of contact sensitizers by monitoring their influence on endocytotic mechanisms in murine LC was developed. Epidermal cell suspensions were labelled with a monoclonal antibody directed to MHC class II molecules and pH-sensitive fluorochrome-coupled second-step reagents. For untreated LC a significant quenching of fluorescence intensity by internalization of the MHC-antibody complexes into acidic compartments was noticed. Similar results were obtained in the …

The belief in an unjust world: An egotistic delusion

1996

The main hypothesis of Lerner's just world theory says that people are inclined to think that their physical and social environment is just and that individuals generally get what they deserve and deserve what they get. Contrary to Lerner's assumption, however, it is suggested in the article that in some situations, people may perceive the world as unjust because such a belief has a specific “ego-defensive” compoment for an individual. It is likely, for instance, that the belief in an unjust world, though in itself a legitimate block to success, may be aggrvated in conditions diagnostic for competence and hence can be used as a special form of self-handicapping strategy. This assumption has…

Environmental conflict as a social construction: Nuclear waste conflicts in Finland

1996

Environmental conflicts are a familiar phenomenon in all industrial societies, and social scientists have produced a great number of studies of different environmental conflicts. One conventional way to conceptualize them is known as NIMBY ("not in my backyard"). Although the recent NIMBY literature has revealed the complexity of the issue, the approach continues to be beset by a number of problems. It has been difficult to conceptualize the dynamic character of a conflict from this perspective. This paper suggests that the theory of environmental conflicts should shift in an epistemological and social interactionist direction, toward social constructionist theory. This paper offers a const…

The influence of nimodipine on chromatolysis of motoneurons following axotomy with and without reinnervation: A quantitative image analysis

1996

Using a recently developed image analysis method to quantify the time course of chromatolysis in injured motorneurons we tested the effect of the calcium entry blocker nimodipine (1000 ppm in food pellets) on regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal anastomosis with complete regeneration and following facial and hypoglossal nerve resection which causes a partial neuronal degeneration and postoperative survival times of 4 to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial sections with a VIDASplus image analyzer. Monitoring alterations of the Ni…