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See detailLe dopage
Kaux, Jean-François ULg

Conference (2012, March 15)

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See detailUse of microbial biosensors to detect substrate heterogeneities at the single cell level and assess microbial viability: Validation of a mini-bioreactor platform
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Conference (2012, March 15)

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor ... [more ▼]

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In this work, we have used these biosensors for the elaboration of a mini-bioreactor platform that can be used as a scale-down tool. Three green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli, i.e. uspA::gfp, csiE::gfp and yciG::gfp. Our previous studies have shown that these kinds of promoters are induced in response of substrate limitation and exhibit a strong fluorescence attenuation when cultivated in heterogeneous bioreactors. This sensitivity to substrate limitation has been confirmed in the case of the csiE and yciG biosensors. A mini scale-down platform has been proposed as a high throughput tool to investigate rapidly the usefulness of a given microbial biosensor. This platform is composed of shake flask able to operate in fed-batch mode either by using the slow release or the intermittent feeding principle. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. Local heterogeneities have thus been reproduced at the level of these mini-bioreactors and these one have caused a decrease of GFP expression, as in conventional scale-down reactor. The presence of GFP in supernatants has also been noticed and seems to be correlated with the substrate limitation signal for the three cultivation systems considered in this work (i.e., chemostat, conventional and mini-bioreactors) and with the membrane permeability. [less ▲]

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See detailLes laboratoires scientifiques amazoniens: Dynamique des relations entre acteurs scientifiques et locaux dans les aires protégés (Équateur)
Escobar Jimenez, Kelly ULg

Learning material (2012)

Le document présente la problématique, l’état des connaissances, la méthodologie, les outils théoriques, les résultats et certaines conclusions de la thèse intitulée: "QUAND LES LIMITES DES SCIENCES ET ... [more ▼]

Le document présente la problématique, l’état des connaissances, la méthodologie, les outils théoriques, les résultats et certaines conclusions de la thèse intitulée: "QUAND LES LIMITES DES SCIENCES ET LES SENTIERS DE CHASSE S’ENTRECROISENT: UNE ETHNOGRAPHIE DE LABORATOIRES SCIENTIFIQUES AMAZONIENS EN PARTENARIAT AVEC LES COMMUNAUTÉS LOCALES AUTOCHTONES" [less ▲]

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See detailQuantifications équivariantes
Radoux, Fabian ULg

Scientific conference (2012, March 15)

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See detailBiomarkers of renal disease
CAVALIER, Etienne ULg

Conference (2012, March 15)

Detailed reference viewed: 4 (0 ULg)
See detailUne prothèse discale!? Ca marche ?! C'est remboursé ?!
Martin, Didier ULg

Scientific conference (2012, March 14)

Detailed reference viewed: 116 (7 ULg)
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See detailRation comparée conventionnelle - bio en élevage de bovin viande et lait
Beckers, Yves ULg

Conference given outside the academic context (2012)

Detailed reference viewed: 25 (1 ULg)
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Peer Reviewed
See detailImpact of Protective Compounds on the Viability, Physiological State and Lipid Degradation of FreezeDried Pseudomonas Fluorescens BTP1 during Storage
Mputu Kanyinda, Jean-Noël ULg; Pierart, C.; Weekers, F. et al

in International Journal of Biotechnology and Biochemistry (2012), 8(4), 17-26

The drying of bacteria remains a major alternative in order to keep them long term. After centrifugation, the bacterial pellet of Pseudomonas fluorescensBTP1 was divided in two fractions one with ... [more ▼]

The drying of bacteria remains a major alternative in order to keep them long term. After centrifugation, the bacterial pellet of Pseudomonas fluorescensBTP1 was divided in two fractions one with protecting compounds (2% glycerol or 5% maltodextrine) and one without and freeze-dried. After freeze drying, powders were sealed in aluminium bag under vacuum and stored at 4 or 20°C. The parameters such as viability, the conductivity and the ratio of polyunsaturated fatty acids/saturated fatty acids were used to investigate the viability of freeze-dried powders during storage. For example cell concentration of powder with glycerol (PG) at CFU/g before storage is 4.109 and after 7 month 2.108 at 4°C and 3,5.107 at 20°C). The ratio of polyunsaturated fatty acids/saturated fatty acids decrease in function of time (e.g. at 4°C the ratios of C18:3 and C18:2 by C16:0 decreases respectively of 0,013 to 0,001 and 0,05 to 0,03 after 60 days of storage). In the present study, flow cytometric analysis was applied to evaluate the state in which the cells are at the end of storage time. We compared the survival results of bacteria obtained by plate count with the flow cytometric analysis results. [less ▲]

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See detailApplications de la résonance magnétique nucléaire à la chimie des actinides et au retraitement des combustibles nucléaires.
Vidick, Geoffrey ULg

Doctoral thesis (2012)

This research work is dedicated to develop and bring to light the contribution of nuclear magnetic resonance (NMR) in the study of the actinide ions and their complexes in aqueous or in organic solvents ... [more ▼]

This research work is dedicated to develop and bring to light the contribution of nuclear magnetic resonance (NMR) in the study of the actinide ions and their complexes in aqueous or in organic solvents. We use several advanced NMR techniques. The dispersion of the longitudinal relaxation time T1 of solvent nuclei with the magnetic field (NMRD) yields information on the magnetic properties of paramagnetic actinide ions. The sensitivity of NMR to the exact nature of the ground state of actinide ions is also illustrated by detailed studies on the complexes of U, Np, Pu, Am and Cm in different oxidation states. It will be shown that the paramagnetic shifts induced by the actinide ions originate from both a through space dipolar contribution and a through bonds contact contribution. The latter gives access to delocalized unpaired electron densities that are directly related to the covalency of the actinide-ligand bonds. However, electronic densities can only be obtained after separation of the two contributions. This separation made thanks three different methods based on studies with variable temperature and by synthesizing highly symmetric and anisotropic complexes. The use of dipolar contribution can be, as for her, related to the geometry of complexes formed in solution. This method of determination of solution structure is illustrated in the case of four specially designed N-polyaromatic ligands actinide/lanthanide partitioning by liquid-liquid extraction, an essential step for the ultimate nuclear fuel reprocessing. Besides their structure determination, the use of NMR techniques allowed of determined the stoechiometry and speciation in solution of these complexes. [less ▲]

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See detailSensitivity of the Oxygen Dynamics in the Black Sea North Western Shelf to physical and biogeochemical processes : 3D model approach
Capet, Arthur ULg; Beckers, Jean-Marie ULg; Grégoire, Marilaure ULg

Conference (2012, March 13)

The presentation evidences the role of benthic oxygen consumption in the seasonal hypoxia afecting the Norht western shelf of the Black Sea. Spatial variability of related processes is evidenced and ... [more ▼]

The presentation evidences the role of benthic oxygen consumption in the seasonal hypoxia afecting the Norht western shelf of the Black Sea. Spatial variability of related processes is evidenced and finally interanual variability of hypoxia severity is quantified and related to nitrogen riverine inputs. [less ▲]

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See detailDispersal ability and speciation mechanisms in bryophytes
Hutsemekers, Virginie ULg

Doctoral thesis (2012)

Detailed reference viewed: 41 (9 ULg)
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See detailMéthodologie de dimensionnement et de confection d’un Seepage Meter artisanal
NITCHEU Martial; MIDEKOR Akoly; Sauret, Elie ULg

Report (2012)

This document is a guideline for the design of seepage meter to direct flux measurements of water exchanged at the interface "groundwater - river". It describes the principles, limitations and advantages ... [more ▼]

This document is a guideline for the design of seepage meter to direct flux measurements of water exchanged at the interface "groundwater - river". It describes the principles, limitations and advantages of the use of seepage meters and provides technical details relevant to the design and manufacture a seepage meter based of the simplified model of Lee (1977). Direct measurements on the Kou River in Burkina Faso (West Africa) is proposed. [less ▲]

Detailed reference viewed: 24 (1 ULg)
See detailThe long period eccentric orbit of the particle accelerator HD167971 revealed by long baseline interferometry
De Becker, Michaël ULg

Conference (2012, March 12)

Particle acceleration and non-thermal emission processes in colliding-wind massive binaries constitute key issues in massive stars physics. The investigation of such processes requires a good knowledge of ... [more ▼]

Particle acceleration and non-thermal emission processes in colliding-wind massive binaries constitute key issues in massive stars physics. The investigation of such processes requires a good knowledge of their stellar, stellar wind and orbital parameters. In this short contribution, I will present the latest results related to the case of HD167971, a system recently resolved by the VLTI. The information on the separation and on the luminosity ratio derived from these observations will also be discussed in the context of the so-called 'standard scenario' for particle acceleration and non-thermal processes in massive stars. [less ▲]

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See detailBudget : Après la rigueur douce, la concurrence dure?
Petit, Nicolas ULg

Article for general public (2012)

L’un des maux endémiques de l’économie belge tient aux pressions concurrentielles insuffisantes sur de nombreux marchés de produits. Faute d’un cadre de surveillance effectif, les prix des biens et ... [more ▼]

L’un des maux endémiques de l’économie belge tient aux pressions concurrentielles insuffisantes sur de nombreux marchés de produits. Faute d’un cadre de surveillance effectif, les prix des biens et services demeurent – comme le décrivent maintes études – plus élevés que dans d'autres États membres, et ce spécialement dans le secteur de la vente au détail et dans les industries de réseaux (énergie, télécommunications, transport ferroviaire, etc.). [less ▲]

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See detailLes sanctions dans la religion grecque antique
Delli Pizzi, Aurian ULg

Scientific conference (2012, March 12)

Detailed reference viewed: 19 (8 ULg)
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See detailPhase retarders in liquid crystals polymers
Piron, Pierre ULg

Scientific conference (2012, March 12)

Liquid crystals polymers posses birefringent properties and they are locally orientable, they allow the realization of space variant optical retarders which creates non uniformly polarized beam. To ... [more ▼]

Liquid crystals polymers posses birefringent properties and they are locally orientable, they allow the realization of space variant optical retarders which creates non uniformly polarized beam. To realize a retarder, liquid crystals are exposed to a UV linearly polarized beam, the optical axis of the retarder will be parallel to the incident polarization. We shall present an innovative way to produce space-variant retarders without mechanical interaction polarization holography . Superposing several beams differently polarized, results in a non-uniformly polarized recording beam used to realize space variant retarders. We shall also present our research retarders for two applications based on this method polarization analysis and coronagraphy. [less ▲]

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See detailApplication of mixed polygenic model to control for cryptic/genuine relatedness and population stratification.
Gusareva, Elena ULg; Mahachie John, Jestinah ULg; Isaacs, Aaron et al

Poster (2012, March 12)

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several ... [more ▼]

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several methods have been proposed for association testing in the presence of population stratification. Among these, principal components-based approaches are the most popular. Principal component analysis (PCA) allows data transformation to a new coordinate system such that the projection of the data along the first new coordinate (called the PC1) has the largest variance; the second PC has the second largest variance, and so on. In practice, two components are usually enough to adjust or to control for population stratification. They can easily be included in parametric association models as covariates. Despite the success of this strategy, there are still some caveats which need further attention. Among these are that principal component-based methods generally do not account for cryptic relatedness (kinship) between supposedly unrelated individuals, are not straightforwardly adapted to accommodate family-based designs or mixtures of families and unrelated individuals, and do not always take proper account of the trait under investigation. In this work, we present an easy-to-use alternative that addresses the aforementioned issues. For quantitative traits, we propose to first use the mixed polygenic model (possibly taking into account important non-genetic confounders as covariates), second to derive “polygenic” residuals from this model – hereby removing genomic kinship relationships, and third to consider these residuals as new traits in a classical genome-wide QTL analysis for “unrelated individuals”. The polygenic component of the aforementioned mixed polygenic model describes the contribution from multiple independently segregating genes, all having a small additive effect on the trait under investigation. Via an extensive simulation study, with various settings of population stratification and admixture, we show that this approach not only removes most of the “relatedness” between individuals (cryptic relatedness or known relatedness), but also removes most of the remaining substructures caused by population stratification or admixture. As a proof of concept, we demonstrate the efficiency of this robust method to control for population stratification on real-life genome-scale data from the SNP Health Association Resource (SHARe) Asthma Resource project (SHARP) (dbGaP accession number phs000166.v2.p1). We also provide leads to extend this method to dichotomous traits. [less ▲]

Detailed reference viewed: 49 (16 ULg)