Les adénomes hypophysaires : du diagnostic au traitement en passant par la contraception, la grossesse et la ménopause

Scientific conference (2013, January)

Le choix entre l’exemption et l’imputation - Cas d’application : la compensation des pertes

in Richelle, Isabelle; Traversa, Edoardo (Eds.) La Fiscalité internationale en Belgique - Tendances récentes (2013)

1. Choix entre taxation territoriale et taxation mondiale 2. La situation en Belgique 3. Incidence de la jurisprudence de la Cour de justice

Transport of dissolved Si from soil to river: a conceptual mechanistic model

in Silicon (2013), 5(1), 115-133

This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a mechanistic model for understanding the transport of Si through a typical podzol ... [more ▼]

This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a mechanistic model for understanding the transport of Si through a typical podzol soil to the river. DSi present in natural waters originates from the dissolution of mineral and amorphous Si sources in the soil. However, the DSi concentration in natural waters will be dependent on both dissolution and deposition/precipitation processes. The net DSi export is controlled by soil composition like (mineralogy and saturated porosity) as well as water composition (pH, concentrations of organic acids, CO2 and electrolytes). These state variables together with production, polymerization and adsorption equations constitute a mechanistic framework determining DSi concentrations. For a typical soil profile in a temperate climate, we discuss how the values of these key controls differ in each soil horizon and how it influences the DSi transport. Additionally, the impact of external forcings such as seasonal climatic variations and land use, is evaluated. This model is a first step to better understand Si transport processes in soils and should be further validated with field measurements. [less ▲]

Modélisation du bilan de masse de surface Antarctique : quelle stratégie et quelle validation ?

Conference (2013, January)

Le bilan de masse de surface (BMS) Antarctique est encore mal connu, bien qu'on sache qu'il contribue de façon significative à l'évolution actuelle du niveau des mers et que sa contribution soit supposée ... [more ▼]

Le bilan de masse de surface (BMS) Antarctique est encore mal connu, bien qu'on sache qu'il contribue de façon significative à l'évolution actuelle du niveau des mers et que sa contribution soit supposée s'intensifier au cours des prochains siècles. Outre son effet direct sur le niveau des mers, le BMS est également un champs de forçage primordial pour les modèles de calotte. Enfin, alors qu'il existe des mesures directes de l'écoulement de la glace vers l'océan et des variations de masse totales (surface+écoulement) de la calotte, il n'existe pas de mesure directe du bilan de masse de surface à l'échelle du continent. La climatologie actuelle du BMS Antarctique est donc estimée principalement à partir de résultats de modélisation. Il est donc crucial de modéliser correctement le bilan de masse de surface Antarctique. Or cette modélisation n'est pas aisée, car il existe peu de modèles de climat, globaux ou régionaux, dont la physique soit appropriée pour modéliser l'atmosphère sur des surfaces englacées. De plus, la résolution a une influence importante sur la représentation du BMS, ce qui oblige à faire des compromis entre résolution et complexité des modèles pour conserver des coûts de calcul raisonnables. Nous présentons la méthodologie que nous avons adoptée pour modéliser le BMS Antarctique sur plusieurs siècles et à haute résolution. Elle s'appuie sur une cascade de modèles adaptés aux conditions polaires à différentes échelles. Nous nous penchons également sur l'épineux problème de l'évaluation du BMS modélisé à partir de données de terrain. En effet, un effort important a été réalisé pour répertorier les données de BMS de qualité en Antarctique, mais ces données restent éparses et échantillonnent mal le continent. L'utilisation d'autres types de données, satellites ou aéroportées par exemple, semble nécessaire et nous ferons un état des lieux des limitations qui restent à dépasser pour y parvenir. [less ▲]

Rates of consumption of atmospheric CO2 through the weathering of loess during the next 100 yr of climate change

in Biogeosciences (2013), 10

Quantifying how C fluxes will change in the future is a complex task for models because of the coupling between climate, hydrology, and biogeochemical reactions. Here we investigate how pedogenesis of the ... [more ▼]

Quantifying how C fluxes will change in the future is a complex task for models because of the coupling between climate, hydrology, and biogeochemical reactions. Here we investigate how pedogenesis of the Peoria loess, which has been weathering for the last 13 kyr, will respond over the next 100 yr of climate change. Using a cascade of numerical models for climate (ARPEGE), vegetation (CARAIB) and weathering (WITCH), we explore the effect of an increase in CO2 of 315 ppmv (1950) to 700 ppmv (2100 projection). The increasing CO2 results in an increase in temperature along the entire transect. In contrast, drainage increases slightly for a focus pedon in the south but decreases strongly in the north. These two variables largely determine the behavior of weathering. In addition, although CO2 production rate increases in the soils in response to global warming, the rate of diffusion back to the atmosphere also increases, maintaining a roughly constant or even decreasing CO2 concentration in the soil gas phase. Our simulations predict that temperature increasing in the next 100 yr causes the weathering rates of the silicates to increase into the future. In contrast, the weathering rate of dolomite – which consumes most of the CO2 – decreases in both end members (south and north) of the transect due to its retrograde solubility. We thus infer slower rates of advance of the dolomite reaction front into the subsurface, and faster rates of advance of the silicate reaction front. However, additional simulations for 9 pedons located along the north–south transect show that the dolomite weathering advance rate will increase in the central part of the Mississippi Valley, owing to a maximum in the response of vertical drainage to the ongoing climate change. The carbonate reaction front can be likened to a terrestrial lysocline because it represents a depth interval over which carbonate dissolution rates increase drastically. However, in contrast to the lower pH and shallower lysocline expected in the oceans with increasing atmospheric CO2, we predict a deeper lysocline in future soils. Furthermore, in the central Mississippi Valley, soil lysocline deepening accelerates but in the south and north the deepening rate slows. This result illustrates the complex behavior of carbonate weathering facing short term global climate change. Predicting the global response of terrestrial weathering to increased atmospheric CO2 and temperature in the future will mostly depend upon our ability to make precise assessments of which areas of the globe increase or decrease in precipitation and soil drainage. [less ▲]

Effects of surfactin on membrane models displaying lipid phase separation.

in Biochimica et Biophysica Acta (2013), 1828(2), 801-815

Surfactin, a bacterial amphiphilic lipopeptide is attracting more and more attention in view of its bioactive properties which are in relation with its ability to interact with lipids of biological ... [more ▼]

Surfactin, a bacterial amphiphilic lipopeptide is attracting more and more attention in view of its bioactive properties which are in relation with its ability to interact with lipids of biological membranes. In this work, we investigated the effect of surfactin on membrane structure using model of membranes, vesicles as well as supported bilayers, presenting coexistence of fluid-disordered (DOPC) and gel (DPPC) phases. A range of complementary methods was used including AFM, ellipsometry, dynamic light scattering, fluorescence measurements of Laurdan, DPH, calcein release, and octadecylrhodamine B dequenching. Our findings demonstrated that surfactin concentration is critical for its effect on the membrane. The results suggest that the presence of rigid domains can play an essential role in the first step of surfactin insertion and that surfactin interacts both with the membrane polar heads and the acyl chain region. A mechanism for the surfactin lipid membrane interaction, consisting of three sequential structural and morphological changes, is proposed. At concentrations below the CMC, surfactin inserted at the boundary between gel and fluid lipid domains, inhibited phase separation and stiffened the bilayer without global morphological change of liposomes. At concentrations close to CMC, surfactin solubilized the fluid phospholipid phase and increased order in the remainder of the lipid bilayer. At higher surfactin concentrations, both the fluid and the rigid bilayer structures were dissolved into mixed micelles and other structures presenting a wide size distribution. [less ▲]

Metabolic Changes in the Spinal Cord After Brachial Plexus Root Re-implantation

in Neurorehabilitation & Neural Repair (2013), 27(2), 118-124

Comprehensive clinical and molecular analysis of 12 families with type 1 recessive cutis laxa.

in Human Mutation (2013), 34(1), 111-21

Autosomal recessive cutis laxa type I (ARCL type I) is characterized by generalized cutis laxa with pulmonary emphysema and/or vascular complications. Rarely, mutations can be identified in FBLN4 or FBLN5 ... [more ▼]

Autosomal recessive cutis laxa type I (ARCL type I) is characterized by generalized cutis laxa with pulmonary emphysema and/or vascular complications. Rarely, mutations can be identified in FBLN4 or FBLN5. Recently, LTBP4 mutations have been implicated in a similar phenotype. Studying FBLN4, FBLN5, and LTBP4 in 12 families with ARCL type I, we found bi-allelic FBLN5 mutations in two probands, whereas nine probands harbored biallelic mutations in LTBP4. FBLN5 and LTBP4 mutations cause a very similar phenotype associated with severe pulmonary emphysema, in the absence of vascular tortuosity or aneurysms. Gastrointestinal and genitourinary tract involvement seems to be more severe in patients with LTBP4 mutations. Functional studies showed that most premature termination mutations in LTBP4 result in severely reduced mRNA and protein levels. This correlated with increased transforming growth factor-beta (TGFbeta) activity. However, one mutation, c.4127dupC, escaped nonsense-mediated decay. The corresponding mutant protein (p.Arg1377Alafs(*) 27) showed reduced colocalization with fibronectin, leading to an abnormal morphology of microfibrils in fibroblast cultures, while retaining normal TGFbeta activity. We conclude that LTBP4 mutations cause disease through both loss of function and gain of function mechanisms. [less ▲]

A micro–macro approach of permeability evolution in rocks excavation damaged zones

in Computers & Geotechnics (2013), 49

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress ... [more ▼]

Excavation damaged zone, with significant irreversible deformations and nonnegligible changes in flow and transport properties generally occurs in indurated clay around underground structures. The stress perturbation around the excavation could lead to a significant increase of the permeability physically due to diffuse and/or localized microcracks growth in the material. In the present study, we investigate microcracks-induced damage processes together with the subsequent modification in permeability. The proposed approach is based on a homogenization-based upper bound extended to the context of micro-cracked media in presence of initial stress. Application of this approach is done on a borehole excavation problem related to the Selfrac in situ experiments on Opalinus Clay. Although, the model fails to quan-titatively account for the in situ permeability change (which may also originated from existing macro-fractures), its prediction shows a significant evolution of the material permeability around the borehole. This is in qualitative agreement with available data. [less ▲]

Mapping Magnetic Near-Field Distributions of Plasmonic Nanoantennas

in ACS Nano (2013)

We present direct experimental mapping of the lateral magnetic near-field distribution in plasmonic nanoantennas using aperture scanning nearfield optical microscopy (SNOM). By means of full-field ... [more ▼]

We present direct experimental mapping of the lateral magnetic near-field distribution in plasmonic nanoantennas using aperture scanning nearfield optical microscopy (SNOM). By means of full-field simulations it is demonstrated how the coupling of the hollow-pyramid aperture probe to the nanoantenna induces an effective magnetic dipole which efficiently excites surface plasmon resonances only at lateral magnetic field maxima. This excitation in turn affects the detected light intensity enabling the visualization of the lateral magnetic near-field distribution of multiple odd and even order plasmon modes with subwavelength spatial resolution. [less ▲]