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Showing papers by "University of Grenoble published in 1999"


Journal ArticleDOI
TL;DR: In this article, the authors investigated the kinetic effect of specific adsorption interactions on the chemical reduction of uranyl (UVIO22+) by ferrous iron, and derived a rate law for surface-catalyzed U(VI) reduction by Fe(II), d[U(VI)] dt =−k[≡ Fe III OFe II OH 0 ][U( VI)] ads where the bimolecular rate constant k has a value of 399 ± 25 M−1 min−1 at 25°C.

647 citations


Journal ArticleDOI
TL;DR: In this paper, a change in the slope of the curve giving the maximum of consistency is observed at a typical water content, due to the presence of excess free water in industrial soft wheat flour.

199 citations


Journal ArticleDOI
01 Jul 1999
TL;DR: In this paper, a self-supporting film of Co-sorbed hectorite was investigated by polarized EXAFS (P-EXAFS) spectroscopy, and the halfwidth at half maximum of the orientation distribution of individual clay platelets off the film normal was determined by quantitative texture analysis, and found to be equal to 18.9°.
Abstract: The local structural environment of Co sorbed on hectorite (a magnesian smectite) has been investigated by polarized EXAFS (P-EXAFS) spectroscopy on a self-supporting film of Co-sorbed hectorite. This sorption sample was prepared by contacting Co and hectorite at pH 6.5 and at high ionic strength (0.3 M NaNO3) to favor pH-dependent sorption reaction over cation exchange. A self-supporting film was elaborated after 120 h of reacting time, when apparent quasi-equilibrium conditions were attained. The half-width at half maximum of the orientation distribution of c* axis of individual clay platelets off the film normal was determined by quantitative texture analysis, and found to be equal to 18.9°. Co K-edge P-EXAFS spectra were recorded at angles between the incident beam and the film normal equal to 0°, 35°, 50°, and 60°; the 90° spectrum was obtained by extrapolation. Spectral analysis led to the identification of the two nearest cationic subshells containing 1.6 6 0.4 Mg at 3.03 A and 2.2 6 0.5 Si at 3.27 A. These distances are respectively characteristic of edge-sharing linkages between Mg and Co octahedra and of corner-sharing linkages between Co octahedra and Si tetrahedra, as in clay structures. The angular dependence of the Co‐Mg and Co‐Si contributions indicates that Co‐Mg pairs are oriented parallel to the film plane, whereas Co‐Si pairs are not. These results are interpreted by the formation of Co inner-sphere mononuclear surface complexes located at the edges of hectorite platelets, in the continuity of the (Mg, Li) octahedral sheet. © 1999 Academic Press

166 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated correlations between an extensive range of geomorphic properties that can be estimated from a digital elevation model and the uplift rate on geological timescales, focusing on an area in the Siwalik Hills (central Nepal), where lithology and climate can be considered as uniform.
Abstract: The present study investigates correlations between an extensive range of geomorphic properties that can be estimated from a digital elevation model and the uplift rate on geological timescales. The analysis focuses on an area in the Siwalik Hills (central Nepal), where lithology and climate can be considered as uniform. This area undergoes rapid tectonic uplift at rates of up to 15 mm yr^(−1), which are derived from the geometric pattern of a fault-bend model of fold growth. The selected geomorphic properties can be divided in two categories, depending on whether or not the vertical dimension is taken into account. None of the planar properties are significantly correlated to uplift rate, unlike those that include the vertical dimension, such as the mean elevation of basins, hypsometric curve, and hypsometric integral, and relief defined by the amplitude factor of length scaling analysis. Correlation between relief and uplift rate is observed for all length scales of topography shorter than 600 m, which suggests that all orders of the streams are able to adjust to the tectonic signal. Simple mass balance considerations imply that the average elevation is only 10% of surface uplift, suggesting that a dynamic equilibrium has been reached quite rapidly. Using a simple two-process model for erosion, we find that fairly high diffusion coefficients (order of 10 m^2 yr^(−1)) and efficient transport of the material by rivers are required. This unusually high value for mass diffusivity at small length scales may be obtained by either a very efficient linear diffusion or by landsliding. Actually, both processes may be active, which appears likely given the nature of the unconsolidated substratum and the favorable climatic conditions. Local relief in the study area may therefore be used to predict either uplift or denudation, but the prediction is calibrated only for that specific climatic and lithologic conditions and cannot be systematically applied to other contexts.

134 citations


Journal ArticleDOI
TL;DR: The authors investigated the effect of short-term asymmetrical outcome dependency (one form of power) on person perception in interpersonal and intergroup situations and found that, in the interpersonal condition only, targets' power (perceiver outcome dependency) led to individuating impression-formation processes (attention and dispositional inferences), consistent with the continuum model of impression formation.

131 citations


Journal ArticleDOI
TL;DR: In this paper, asphaltene samples extracted from archeological and geological bitumens from the Middle East, France, and Spain were studied by sulfur K- and L-edge X-ray absorption near-edge structure (XANES) spectroscopy in combination with isotopic analyses (d 13 C and dD).

118 citations


Journal ArticleDOI
TL;DR: A new algorithm to compute the set of rational solutions of a system of linear differential equations with coefficients in K(x)logx is proposed and implemented in Maple V and it turns out to be faster than cyclic vector computations.

116 citations


Journal ArticleDOI
TL;DR: The mechanism of Co uptake from aqueous solution onto hectorite (a magnesian smectite) and its impact on the stability of this clay mineral were investigated as a function of Co concentration and ionic strength by combining kinetics measurements and Co K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy as discussed by the authors.

95 citations


Journal ArticleDOI
TL;DR: Comparison of the action of cellulosomes with that of fungal enzymes indicated that the degradation of cellulose crystals by cellulosome occurred with only limited levels of processivity, in contrast with the observations reported forFungal enzymes.
Abstract: The action of cellulosomes from Clostridium thermocellum on model cellulose microfibrils from Acetobacter xylinum and cellulose microcrystals from Valonia ventricosa was investigated. The biodegradation of these substrates was followed by transmission electron microscopy, Fourier-transform IR spectroscopy and X-ray diffraction analysis, as a function of the extent of degradation. The cellulosomes were very effective in catalysing the complete digestion of bacterial cellulose, but the total degradation of Valonia microcrystals was achieved more slowly. Ultrastructural observations during the digestion process suggested that the rapid degradation of bacterial cellulose was the result of a very efficient synergistic action of the various enzymic components that are attached to the scaffolding protein of the cellulosomes. The degraded Valonia sample assumed various shapes, ranging from thinned-down microcrystals to crystals where one end was pointed and the other intact. This complexity may be correlated with the multi-enzyme content of the cellulosomes and possibly to a diversity of the cellulosome composition within a given batch. Another aspect of the digestion of model celluloses by cellulosomes is the relative invariability of their crystallinity, together with their Ialpha/Ibeta composition throughout the degradation process. Comparison of the action of cellulosomes with that of fungal enzymes indicated that the degradation of cellulose crystals by cellulosomes occurred with only limited levels of processivity, in contrast with the observations reported for fungal enzymes. The findings were consistent with a mechanism whereby initial attack by a cellulosome of an individual cellulose crystal results in its 'commitment' towards complete degradation.

80 citations


Journal ArticleDOI
TL;DR: The positive effect of walnut consumption on blood HDL cholesterol and apo A1 is of special interest since these lipid parameters have been shown to be negatively correlated with cardiovascular morbidity.

79 citations


Journal ArticleDOI
TL;DR: While 17 strains depleted isoproturon over 50% only 4 depleted diuron and 2 chlortoluron at the same level and the best results were obtained with Bjerkandera adusta and Oxysporus sp which were the most efficient towards the 3 substrates.

Journal ArticleDOI
TL;DR: In this paper, the authors performed Particle Induced X-ray Emission (PIXE) and PIGE analyses with an external proton millibeam on archaeological bones to determine possible alteration processes in their burial environment (dissolution, uptake and diffusion of foreign ions).
Abstract: We have performed Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma-ray Emission (PIGE) analyses with an external proton millibeam on archaeological bones in order to determine possible alteration processes in their burial environment (dissolution, uptake and diffusion of foreign ions). The PIXE method enables us to quantify the post-mortem alteration by determining the concentration profile of several trace elements like Al, Si, S, Mn, Fe, Cu, Zn and Sr in transverse bone sections, while that of fluorine is inferred from PIGE analysis. Examples of concentration profiles of archaeological bone cross sections from the Seine river site in Paris, Bercy (4000 B.C.), are shown.


Journal ArticleDOI
TL;DR: The results suggest that the Tat protein, via direct or indirect mechanisms, increases proliferation, sensitizes cells to apoptosis, and changes the conformation of Sp1, affecting its ability to bind to its cognate DNA sequence and to retain its zinc.

Journal ArticleDOI
TL;DR: Although the detection of the minus‐strand HCV RNA reliably identifies the presence of replicating HCV in its target organ, the quantitative measurement of viremia remains the clinically meaningful “golden standard” for assessing the level of HCV replication.

Journal ArticleDOI
TL;DR: In this article, a ductile shearing event is recognized in gneisses and barite veins of the crystalline internal massifs of the Alpine Maghrebides in Algeria.

Journal ArticleDOI
P. Abreu1, Wolfgang Adam2, Tim Adye3, Petar Adzic  +562 moreInstitutions (51)
TL;DR: In this paper, infrared and collinear safe event shape distributions and their mean values are determined using the data taken at five different centre of mass energies above MZ with the DELPHI detector at LEP from the event shapes, the strong coupling αs is extracted in View the MathML source(αs2), NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz

Journal ArticleDOI
TL;DR: In this paper, the authors prove a bijection between the slopes of a holonomic D -module and its characteristic exponants, and then define its Newton Polygon, where the exponant is related to the growth of solutions, and the slopes are rational numbers calculated algebraically from the micro-characteristic varieties.
Abstract: The aim of this paper is to prove a bijection between the slopes of a holonomic D -module and its characteristic exponants, and then to define its Newton Polygon. The slopes are rational numbers which are calculated algebraically from the micro-characteristic varieties, while the characteristic exponants are related to the growth of solutions.

Journal ArticleDOI
TL;DR: In this article, the authors construct approximate solutions to the time-dependent Schrodinger equation for small values of ħ. If V satisfies appropriate analyticity and growth hypotheses and \(\, these solutions agree with exact solutions up to errors whose norms are bounded by ħ and σ > 0.
Abstract: We construct approximate solutions to the time–dependent Schrodinger¶equation $$$$ for small values of ħ. If V satisfies appropriate analyticity and growth hypotheses and \(\), these solutions agree with exact solutions up to errors whose norms are bounded by $$$$ for some C and γ>0. Under more restrictive hypotheses, we prove that for sufficiently small T′, \(\) implies the norms of the errors are bounded by $$$$ for some C′, γ′>0, and σ > 0.

Journal ArticleDOI
TL;DR: This paper presents a synthesis of the mathematical properties of both neural oscillator versions, and achieves the coupling of two oscillators in order to study how synaptic connections affect the phase lag.

Journal ArticleDOI
TL;DR: It is shown that efficient gene transfer can be achieved in vitro using as a vector a polyvalent peptide derived from the N-terminal sequence of the human adenovirus fiber protein.
Abstract: New strategies to improve the outcome of gene therapy often employ a nonviral gene delivery, which is most likely to fulfil microbiological safety criteria and be retained in the clinical setting. Here we show that efficient gene transfer can be achieved in vitro using as a vector a polyvalent peptide derived from the N-terminal sequence of the human adenovirus fiber protein. The level of transfection is better than that obtained with the two liposomes, DOTAP and DOSPER. Internalization was studied by confocal microscopy using fluorescently marked peptide and DNA. The peptide alone is targeted to the nucleus and concentrated within the nucleolus. Similarly, DNA complexed with peptide also enters the nucleolus, where it is retained for at least 48 h. Peptide I appears to attach to cells by a saturable process, as preincubation of cells with peptide blocks transfection and there is no transfection at 4°C. The peptide contains three domains: a nuclear localization signal of adenovirus fiber protein; a domain containing hydrophobic and polar residues harboring an internalization signal for receptor-mediated endocytosis; and a stretch of lysines. Each of these domains is required for optimum gene transfer. Peptide I may be an interesting alternative to known vectors for gene transfer, for local administration and for ex vivo applications.

Journal ArticleDOI
TL;DR: In this paper, sufficient conditions for existence and uniqueness of rate boundary value problems were proved for incrementally non-linear models not descending from a rate potential and thus are not included into the Hill theory framework.

Journal ArticleDOI
TL;DR: In this article, a novel protoberberine-type alkaloid, along with palmatine, has been isolated and characterized from an anti-HIV active extract from Enantia chlorantha.

Journal ArticleDOI
P. Abreu1, Wolfgang Adam2, Tim Adye3, Petar Adzic  +557 moreInstitutions (51)
TL;DR: In this article, the DELPHI measurements at 130, 136, 161, 172 and 183 GeV are presented as a function of the variables rapidity, ξp, p and transversal momenta.

Journal ArticleDOI
TL;DR: In this paper, a family of random functions with a characterization of its finite dimensional law is described for the purpose of numerically studying sahelian storm rainfields, and two solutions to bypass those problems are provided, according to the regularity properties of the marginal cumulative distribution function.
Abstract: For the purpose of numerically studying sahelian storm rainfields, a family of random functions is described with a characterization of its finite dimensional law. Some problems appearing when fitting its functional parameters are put forward and two solutions to bypass those problems are provided, according to the regularity properties of the marginal cumulative distribution function. An illustration of this method is implemented on a set of sahelian rainfields of event accumulation displaying a strong spatial intermittency.

Journal ArticleDOI
TL;DR: The ring imaging Cherenkov detectors of DELPHI represent a large-scale particle identification system which covers almost the full angular acceptance as mentioned in this paper, and have been used for more than five years at full physics performance.
Abstract: The Ring Imaging Cherenkov detectors of DELPHI represent a large-scale particle identification system which covers almost the full angular acceptance of DELPHI. The combination of liquid and gas radiators (C4F10, C5F12, and C6F14) provides particle identification over the whole secondary particle momentum spectrum at LEP I and LEP II. Continuing optimisation on the hardware as well as on the online and offline software level have resulted in a stable operation of the complete detector system for more than five years at full physics performance.

Journal ArticleDOI
TL;DR: In this article, it was shown that MinEnt (Y) ∥Y∥ = MinEnt(X) √ X ∥X∥, for manifolds Y whose fundamental group is a subexponential extension of the fundamental group of some negatively curved, locally symmetric manifold X, is a particular case of a more general result holding for an arbitrary representation ρ : π1 (Y), →π1 (X), which relates the minimal entropy and the simplicial volume of X to some invariants of the couple (Y, ker (ρ)).
Abstract: We prove that MinEnt (Y) ∥Y∥ = MinEnt(X) ∥X∥, for manifolds Y whose fundamental group is a subexponential extension of the fundamental group of some negatively curved, locally symmetric manifold X. This is a particular case of a more general result holding for an arbitrary representation ρ : π1 (Y) →π1 (X), which relates the minimal entropy and the simplicial volume of X to some invariants of the couple (Y, ker (ρ)). Then, we discuss some applications to the minimal volume problem and to Einstein metrics.

Journal ArticleDOI
P. Abreu1, Wolfgang Adam2, Tim Adye3, Petar Adzic  +554 moreInstitutions (48)
TL;DR: In this paper, a search event with one jet and at most one isolated lepton used data taken at LEP-2 by the DELPHI detector at a center-of-mass energy of 183 GeV.

Journal ArticleDOI
TL;DR: In this article, 4-mercaptophenylboronic acid derivatives were obtained by a metallation/boration sequence from S-protected 4-bromothiophenols; the tbutyldimethylsilylthioether was found suitable to allow subsequent regeneration of the mercapto group after boration.

Journal ArticleDOI
TL;DR: A selection of 39 strains of micromycetes known as good degraders of polychlorinated aromatic compounds, mostly isolated from soil and belonging to various taxonomic groups, have been investigated for fluoranthene degradation.