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See detailIdentification of the main parameters controlling the plasticity of ceramic pastes: The case study of the Marrakech region (Morocco)
El Boudour El Idrissi, Hicham ULg; Daoudi, Lahcen; Fontaine, François ULg et al

Poster (2015, July)

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the ... [more ▼]

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the artisans. To reach this goal, we characterize by X-ray diffraction, granulometry and plasticity index (PI) the local raw clayey material. <br />The investigation of 26 whole pastes shows the dominance of quartz (20 to 50%) and clay minerals (25 to 60%) with K-feldspar (2 to 17%), plagioclase (2 to 25%), calcite (0 to 18%), dolomite (0 to 15%), goethite (0 to7%) and trace of hematite and anhydrite (< 3%). Amphibole occurs in trace (< 5%) but only in some samples. The clay minerals are diversified, including illite (10 to 40%), kaolinite (2 to 15%), mixed-layer (ML) (0 to 10%), smectite, vermiculite and chlorite (0 to 5%), and pyrophyllite-talc association (0 to 8%). Sepiolite (12%) is only present in one paste. The grain size is made by variable proportions of sand (5 to 65%), silt (12 to 53%) and clayey fraction (18 to 66%). <br />The Plasticity index (PI) indicates the presence of two principals groups of pastes. <br />(1) The first group is characterized by PI values ranging between 15 to 18. Their moderate plasticity behavior is related either to the low rate of clayey fraction and/or to the absence of plastic clays like smectites and mixed layer with smectitic sheets. <br />(2) The PI of second group ranges between 20 to 32. The high plasticity values are influenced by the presence of specific clayey minerals like talc-pyrophyllite or sepiolite, or by the high content of smectite plus smectitic mixed-layers within the clayey (< 2 micron) fraction. Only one sample without any of these plastic minerals but with a high content of clayey fraction is characterized by a high PI value (24). <br />We concluded that the workability of ceramic paste in Marrakech region is controlled by a combination of factors, dominated by the grain size distribution and the content in plastic clay minerals within the fine fraction. [less ▲]

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See detailGlucosinolates and by-products in rapeseed meal related to hydrothermal processing
Quinsac, A.; Carré, P.; Fauconnier, Marie-Laure ULg et al

Poster (2015, July)

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The ... [more ▼]

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The RSM nutritional quality may be then lowered for monogastrics, due to GSL breakdown products whose reliable and “easy to use” indicators lack. [less ▲]

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See detailEvaluation of phosphorus bioavailability according to the soil organic matter content
Barbieux, Sophie ULg; Colinet, Gilles ULg

Poster (2015, July)

Phosphorus (P) is an essential nutrient for plants. The organic matter contains significant amounts of P which can be mineralized and supply soil solution. We hypothesize that increasing P organic pools ... [more ▼]

Phosphorus (P) is an essential nutrient for plants. The organic matter contains significant amounts of P which can be mineralized and supply soil solution. We hypothesize that increasing P organic pools in soils is a way to improve its progressive release for plants and alleviate risks of immobilization in mineral forms. The main objective of this study is to evaluate the P bioavailability and its uptake by plants according to the soil organic matter (SOM) content. The experimental protocol is based on a micro-culture in pots. The test-plant used is ryegrass (Lolium perenne L.). Eight silty soils were selected from vegetable gardens (5) and from a long-term fertilization trial on field (3). They present a gradient of SOM (from 2 to 9 %) and available P content (from 5 to 55 mg/100g). Plants were first grown in pure sand and P-free Hoagland nutritive solution. Ten days after plant emergence, roots were brought into contact with the studied soil during about one month. The experiment was stopped after three harvests (every 10 days) and three growth cycles. At the end of the experimentation, analyses were performed on plant material (biomass, P content) and on soil (soluble P, available P, microbial P, pH, phosphatase activity, hot water carbon, nitrate). Besides this study, an incubation experiment was carried out with the same soils without plant to assess soil P status at each harvest time. Paper will present the main findings of the experiment. Especially, the following issues should find answers: (1) do higher levels of SOM and organic phosphorus modify the evolution of P content in soil solution and its uptake by plants?, (2) are the biological processes involved in P cycling promoted in soils with higher SOM content? [less ▲]

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See detailNew asteroseismic analysis of the subdwarf B pulsator PG 1219+534
Péters, M.-J.; Van Grootel, Valérie ULg; Dupret, Marc-Antoine ULg et al

Poster (2015, July)

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See detailQuasar radio polarizations align with large quasar group major axes
Pelgrims, Vincent ULg; Hutsemekers, Damien ULg

Poster (2015, July)

Using quasar polarizations and a sample of large quasar groups drawn from the SDSS DR7, we showed that at HIGH REDSHIFTS (z ~ 1.5) the spin axis orientations of black holes are correlated to the major ... [more ▼]

Using quasar polarizations and a sample of large quasar groups drawn from the SDSS DR7, we showed that at HIGH REDSHIFTS (z ~ 1.5) the spin axis orientations of black holes are correlated to the major axes of the groups to which they belong. Inside very rich groups the BH spins are aligned with the major axes. When the richness decreases, the spin axes become preferentially perpendicular. [less ▲]

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See detailDriving Pulsation Modes in Models of the Two Pre-ELM Helium-Core White Dwarfs WASP 0247-25B and WASP 1628+10B
Van Grootel, Valérie ULg; Fontaine, G.; Brassard, P. et al

Poster (2015, July)

Multi-periodic pulsations have recently been detected in two pre-extremely low mass (pre- ELM) helium-core white dwarfs as reported in Maxted et al. (2013, Nature, 498, 463) and Maxted et al. (2014, MNRAS ... [more ▼]

Multi-periodic pulsations have recently been detected in two pre-extremely low mass (pre- ELM) helium-core white dwarfs as reported in Maxted et al. (2013, Nature, 498, 463) and Maxted et al. (2014, MNRAS, 444, 208). As such, they define a new class of pulsating stars in the HR diagram. Both objects are the secondary components in eclipsing close binaries, with solar-type main sequence stars as primaries. They are believed to be the remnants of former red giant stars stripped down of most of their mass through an active phase of binary evolution. The first of those is WASP 0247-25B, characterized by M = 0.186 ± 0.002 Mʘ, log g = 4.576 ± 0.011, and Teff = 11,380 ± 400 K (Maxted et al. 2013). Three pulsation modes have been detected so far, with periods of 381 s, 406 s, and 421 s. The second one, showing two modes with 669 s and 755 s, is WASP 1628+10B, with M = 0.135 ± 0.020 Mʘ, log g = 4.49 ± 0.05, and Teff = 9200 ± 600 K (Maxted et al. 2014). Adiabatic calculations using suitable evolutionary models have been presented in these publications, showing that the pulsation periods correspond to low-degree, mid-order p-mode oscillations (probably including radial modes). The question of the driving mechanism, however, has been left open, and we address that issue here. [less ▲]

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See detailLand erosion and associated evolution of clay minerals assemblages in Mediterranean region (Southern Turkey): Amik Lake
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Lebeau, Helene et al

Poster (2015, July)

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic ... [more ▼]

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to the East Anatolian Fault Zone in the north. The study focuses on the mineralogy and clay mineralogy record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major mineralogical and clay minerals evolution in the area over the last 4000 years and assess changes that would be related to the different land uses during the different Bronze, Roman, Ottoman and Modern civilizations. Sediments were collected at 1 to 2 cm intervals in core sediments up to a depth of 6 meters in the clay deposits. Geochemistry (XRF), mineralogy (XRD) and clay mineralogy are applied to study the sediment records. The age of the record is constrained combining radionuclide and radiocarbon dating. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Abundant mixed-layer and partly disordered minerals characterize the different sedimentary levels recorded in those cores. Levels relatively rich in chlorite, illite and quartz are interpreted as corresponding to relatively dry periods, while more humid periods lead to more intensive weathering and consequently to the dominance of clay minerals more advanced in the relative stability scale, such as kaolinite. Smectite is taken to indicate a climate with contrasting seasons and a pronounced dry season. The sedimentary record clearly shows two periods indicating strong soil erosion in the Lake catchment. The most recent erosion phase is modern. The oldest one would have started during the late Bronze period and lasted until the late Roman Period. The first and older period is attributed to a strong aggradation linked to major increase in erosion. Our study shows that this episode has specific characteristics: mixed-layer clay mineral, high percent in Ni, Cr and Mg coupled with significant amount of organic matter of terrestrial origin. Ni and Mg most probably come from the Amanos Mountains an ophiolitic belt indicating an intensive upland cultivation and possible exploitation of its mineral resource. The second period is attributed to the modern period. The signature of the increase in erosion is different, because most of the soil cover has already been eroded. Only a patchy thin and unmature soil cover exists since the Late Roman time. Erosion is associated with a marked increase of smectite-illite interstratified clay, goethite and hematite found in deep soil horizons. Moreover, a marked increase in Cr is showed and is probably related to an enhanced exploitation of its mineral resource and to a renew land exploitation of the Amanos Mountain Range. [less ▲]

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See detailCan we trust Type Ia Supernovae as cosmological tools? - Critical analysis and alternative processing of SCP Supernovae data
Hauret, Clémentine ULg; Magain, Pierre ULg

Poster (2015, July)

Current processing to standardize Type Ia Supernovae SCP data produces a significant bias in favour of a particular cosmological model, the flat ΛCDM model. To reduce this bias, we develop an alternative ... [more ▼]

Current processing to standardize Type Ia Supernovae SCP data produces a significant bias in favour of a particular cosmological model, the flat ΛCDM model. To reduce this bias, we develop an alternative, model-independent, methodology. [less ▲]

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See detailScreening of medicinal plants from Reunion Island for antimalarial activity
Ledoux, Allison ULg; Bordignon, Annélise ULg; Campos, Pierre-Éric et al

Poster (2015, July)

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See detailClose-in planets around sdB stars: A step toward constraining their masses ?
Charpinet, S.; Grandjean, A. H. M. J.; Fontaine, G. et al

Poster (2015, July)

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See detailDevelopment of quantification methods applied to HSS alloys for carbides volume fraction and grain size assessments
Tchuindjang, Jérôme Tchoufack ULg; Paydas, Hakan ULg; Hashemi, Seyedeh Neda ULg et al

Poster (2015, July)

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly ... [more ▼]

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly due to the presence of primary carbides within the microstructure. Depending of the initial chemical composition several types of carbides can precipitate in HSS such as MC (Nb and V-rich), M2C (Mo and W-rich), Cr-rich M7C3, etc. Two groups of HSS were analysed in this study, which are the so-called cast HSS grades that are manufactured by a centrifugal casting process and the cladded HSS manufactured by laser cladding. Purpose: Quantify the carbide volume fractions and the grain size within HSS grades in order to set correlations between the microstructure and both the mechanical and the tribological properties of the materials. Findings: The metallurgical features such as carbides nature and shape have been determined that are related to the manufacturing process of the studied material, and several methods have been used to quantify the carbide volume fractions and to assess the grain size. [less ▲]

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See detailThe Period-Effective Temperature Relation for DBV White Dwarfs
Fontaine, G.; Van Grootel, Valérie ULg; Bergeron, P. et al

Poster (2015, July)

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See detailTowards precision β-decay measurements with laser cooled 35Ar
Glover, Rohan ULg; Lenaers, Florence ULg; Velten, Philippe et al

Poster (2015, July)

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See detailThe microbiome from the Lyme disease principal reservoir host in southern Quebec (Peromyscus leucopus)
André, Adrien ULg; Mouton, Alice ULg; Millien, Virginie et al

Poster (2015, June 25)

The emergence of the Lyme disease in Southern Quebec appears directly linked to the recent arrival in the region of the rodent Peromyscus leucopus. Indeed, this species is considered to be the principal ... [more ▼]

The emergence of the Lyme disease in Southern Quebec appears directly linked to the recent arrival in the region of the rodent Peromyscus leucopus. Indeed, this species is considered to be the principal reservoir of the bacteria Borrelia Burgdorferei, responsible of the Lyme disease and the recent climatic warming has allowed the mice to colonize higher latitude territories. Other factors, like the regulation made by pathogens might as well play an important role in the dynamic of expansion of P. leucopus. In our project, we sampled several populations of P. leucopus from the North American border, where the species is thought to be present for 30 years, to the most recently colonized zones, situated approximatively 150km inside of the Quebec province. A characterisation of their microbiome was then performed from their liver, spleen and lungs. Our objectives are threefold: First, we settled a protocol based on NGS methods for the detection of Borrelia Burgdorferei in micro-mammal internal organs. Second, we plan to identify the Borreliosis infection zones and to study their spatio-temporal evolution. Third, we aim to test which of the central-marginal hypothesis or the enemy release hypothesis is best describing the scenario presently happening in southern Quebec concerning the distribution’s expansion of P. leucopus. These information will be of great interest to understand the dynamic of emergence of the Borreliosis and to predict the current and future distribution of this disease in order to inform the Canadian health authorities. [less ▲]

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See detailA hydrochemical - isotopic approach for assessing factors controlling the regional pollution of an urban aquifer
Gesels, Julie ULg; Orban, Philippe ULg; Popescu, Ileana-Cristina et al

Poster (2015, June 24)

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ... [more ▼]

The alluvial aquifer of the Meuse River is contaminated at regional scale in the urbanized and industrialized area of Liège in Belgium, in particular inorganics pollutants such as sulfate, nitrate and ammonium. The sources of those contaminants are numerous: brownfields, urban waste water, subsurface acid mine drainage from former coal mines, atmospheric deposits related to former pollutants emissions in the atmosphere ... Sulfate, nitrate and ammonium are both typical pollutants of the aquifer and tracers of the possible pollution sources. In the Water Framework Directive context, a detailed hydrogeochemical characterization of groundwater was performed. The aim is to determine the origin of the inorganic contaminations, the main processes contributing to poor groundwater quality and the spatial extent of the contaminations. A large hydrochemical sampling campaign was performed, based on 71 selected representative sampling locations, to better characterize the different vectors (end-members) of contamination of the alluvial aquifer and their respective contribution to groundwater contamination in the area. Groundwater samples were collected and analyzed for major and minor compounds and metallic trace elements. The analyses also include stable isotopes in water, sulfate, nitrate, ammonium, dissolved inorganic carbon, boron and strontium. Different hydrogeochemical approaches are combined to obtain a global understanding of the hydrogeochemical processes at regional scale. Hydrochemical interpretations are based on classical diagrams, spatial distribution maps, geochemical equations, multivariate statistics such as self-organizing maps and isotopic analyses. With this combined approach, the location of the contaminant sources and most contaminated sectors of the alluvial aquifer together with a better understanding of geochemical processes involved are obtained. Redox processes strongly influence the composition of groundwater, specifically for compounds degrading the quality of groundwater in the area (sulfate, nitrate and ammonium). The highest concentrations of sulfate can be associated with the post-mining stage in the acid mine drainage process. Various reactions involving nitrogen compounds have been identified and allow a better understanding of causes of high concentrations of ammonium and nitrate. Denitrification and sulphate reduction are also demonstrated based on isotopic ratios. [less ▲]

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See detailFULLY AUTOMATED ELECTROPHORETICALLY MEDIATED MICROANALYSIS SYSTEM FOR CYP1A1 ACTIVITY MONITORING
Farcas, Elena ULg; Servais, Anne-Catherine ULg; Lamalle, Caroline ULg et al

Poster (2015, June 23)

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The ... [more ▼]

Introduction Since the efficacy and toxicity of drugs are closely related to their pharmacokinetics, a good understanding of metabolic pathways is important at an early stage of development. The identification of the enzymes involved in drug metabolism is thus of critical importance for the design of further clinical studies. The availability of specifically expressed human CYPs, namely supersomes, allows the investigation of the contribution of a single metabolic enzyme to the biotransformation pathway of the compound under investigation. CYP1A1, a member of the cytochrome P450 superfamily, was studied in this project. Interestingly, it has been described to be over expressed in various types of cancer. Consequently, CYP1A1 has emerged as a particularly interesting target for cancer therapy. Methods All the experiments were carried out on a HP3DCE system equipped with an on-column DAD. The EMMA procedure was performed by injecting a plug containing CYP1A1 supersomes, followed by a plug that contained the co-factor and the substrate, then another plug of CYP1A1 supersomes. The reaction was triggered by the application of a voltage switch. The voltage was then turned off to allow the metabolic reaction to occur. The separation of the components was then performed at -25 kV. Results The present study describes the development of a fully automatized in-capillary method to follow metabolization of 7-hydroxycoumarin and screen CYP1A1 inhibitors. After preliminary studies, satisfying results were obtained using CYP1A1 at a concentration of 200 pmol/mL, while the incubation time was settled to 15 min. Equal reactant plugs were injected at -50 mbar for 6 sec. The short-end injection performed gave rise to a baseline separation of the molecules (substrate, product, CYP1A1 and NADPH) in less than 2 minutes. Adequate plugs overlap was obtained using electrophoretic mixing. The DoE performed highlighted that the voltage switch has a great impact on the metabolite formation. The amount of product obtained in the optimal conditions was found to be comparable to the one detected after conventional off-line metabolization. Besides the interest of developing an automatized CE approach for metabolisation studies, we also wanted to investigate the potentiality of this approach to screen CYP1A1 inhibitors. The ability of our system to monitor CYP1A1 inhibition was undertaken with apigenin, a well-known inhibitor. It is noteworthy that the compatibility of our system with MEKC ensures its applicability to a large variety of molecules. Novel aspect Monitoring CYP1A1 activity using a rapid and fully automated EMMA method that could be used for new anticancer agents screening. [less ▲]

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See detailFate of the coactivator in the induction of BlaP β-lactamase in Bacillus licheniformis 749/I
Dauvin, Marjorie ULg; Amoroso, Ana Maria ULg; Joris, Bernard ULg

Poster (2015, June 23)

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external ... [more ▼]

In bacteria, the production of a β-lactamase, an hydrolase specific to β-lactam antibiotics, may be constitutive or inducible. In Bacillus licheniformis 749/I the presence of a β-lactam in the external media is detected by a protein relay producing an intracellular signal which leads to the induction of BlaP β-lactamase expression. The blaP gene is included in a divergeon along with blaI, coding for a cytoplasmic repressor, and blaR1, coding for a penicillin membrane receptor. Both, the acylation of the extracellular domain of BlaR1 by a β-lactam together with cellular stress due to the presence of the antibiotic outside the cell generate a dipeptide (coactivator) resulting from the peptidoglycan turnover that destabilizes BlaI repressor-DNA complex, leading to the expression of β-lactam resistance. [less ▲]

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See detailRecovery of language comprehension in the minimally conscious state studied by FDG-PET
Wannez, Sarah ULg; Thibaut, Aurore ULg; Vitali-Roscini, Gaia et al

Poster (2015, June 21)

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See detailBaltic seagrass meadows as a sediment carbon sink
Jankowska, Emilia; Włodarska-Kowalczuk, Maria; Michel, Loïc ULg et al

Poster (2015, June 17)

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See detailUse of 16S rDNA Metagenetics and classical Microbiology to Assess the bacterial superficial Contamination Patterns in Bovines Classically Slaughtered or following the Halal Ritual
Korsak Koulagenko, Nicolas ULg; Taminiau, Bernard ULg; Hupperts, Caroline et al

Poster (2015, June 17)

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining ... [more ▼]

In Belgium and in several European countries, two cattle slaughtering protocols exist: the classical method, that encompasses a stunning step before the sticking procedure, and the halal method, combining the stunning and the sticking in one single step. The main difference lies in the fact that, in the halal protocol, a single cut with a sharp knife is practiced directly on live cattle, instead of two cutting steps with two different knives for the sticking in the classical slaughtering technique. The unique section in the halal technique results generally in the cross section of trachea and esophagus of cattle. The aim of this study was to seek if the two slaughtering techniques were similar regarding the superficial contamination of carcasses, swabbed between 2 and 4 hours after the killing step. For this purpose, classical microbiological tests (TVC and Enterobacteriaceae) and 16S rDNA metagenetic analysis were carried out from 20 cattle carcasses (swabbing of “legal” zone – 1.600 cm2 – and in the neck area – 200 cm2). The classical microbiological results revealed no significant differences between the two slaughtering practices. Statistical analysis of pyrosequencing data showed that differences in bacterial population abundance between slaughtering methods were mainly found in the “legal” swabbing zone compared to the neck area. Bacterial genera belonging to Actinobacteria (Brevibacterium, Corynebacterium) were more aundant in “Halal” samples whereas populations from the Proteobacteria (Caulobacteraceae, Comamonadaceae, Bradyrhizobiaceae) and Firmicutes (Lactobacillus) were more abundand in the “classical” group. The analysis of OTU abundance of bacteria from the digestive or respiratory tract revealed no differences beteween groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis to the genus level underlines differences between methods, the legal swabbing zone being still the best sampling zone compared to the neckline. The next step will be the identification of precise contamination origin of the differences found between slaughtering methods. [less ▲]

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See detailMorphological and functional characterization of Carnobacterium maltaromaticum isolated from vacuum-packed beef with long shelf life
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Ndedi Ekolo, François ULg et al

Poster (2015, June 17)

Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the ... [more ▼]

Temperatures near the freezing point of meat (−1.5 °C), associated with vacuum packaging, allows the preservation of this product up to several months, which makes possible the meat trade across the planet without resorting to freezing. Other the type of packaging and the storage temperature, the shelf-life of meat is directly related to its initial microbiological ecosystem and its evolution. Carnobacterium maltaromaticum is a lactic acid bacterium, and many lactic acid bacteria associated with meat are known for their bactericidal or bacteriostatic activity against other strains, species or genera of bacteria. In this way, the presence of certain lactic acid bacteria adapted to a low temperature in fresh meat could extend the shelf life and improve the microbial stability and safety of this product. The aim of this study was to perform a morphological and functional characterization of a C. maltaromaticum strain (lab. ref. CFAUS2/DLC/4/E1) with potential bioprotective effect isolated from commercial vacuum packaged long shelf life beef. The morphological, biochemical and enzymatic profiles, the influence of different temperatures and atmospheres, and the microbial stability of fresh beef inoculated with the C. maltaromaticum strain were evaluated. Morphological, biochemical and enzymatic profiles of the isolated C. maltaromaticum strain were similar to those of two reference strains (LMG 11393 and LMG 22902). The evaluation of the influence of different atmospheres showed that the growth of C. maltaromaticum was the slowest in an atmosphere containing 70 % O2 and 30 % CO2. Vacuum packaging is therefore more suitable for the growth of this bacterium. An antimicrobial effect against Enterobacteriaceae was highlighted on inoculated fresh meat. The functional characterization of this strain will be further pursued by genotypic characterization and its potential bioprotective effect will also be studied. [less ▲]

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See detailModélisation de la mortalité de larves d'Hylotrupes bajulus (L.) par traitement anoxique pour la conservation d'objets d'intérêt patrimonial
de Streel, Géraud; Henin, Jean-Mac; Mercier, Emmanuelle et al

Poster (2015, June 16)

Au cours des dernières décénnies, les preuves scientifiques concernant les dangers des insecticides utilisés pour éliminer les insectes présents dans les œuvres d’art des points de vue de la santé du ... [more ▼]

Au cours des dernières décénnies, les preuves scientifiques concernant les dangers des insecticides utilisés pour éliminer les insectes présents dans les œuvres d’art des points de vue de la santé du personnel et des visiteurs, des risques environnementaux et des risques pour les œuvres ont conduit le monde de la conservation patrimoniale à se tourner vers des techniques alternatives de désinsectisation. Le traitement par anoxie fait partie de ces techniques. Il s’agit de soumettre les insectes à une atmosphère à faible teneur en oxygène (généralement < 0.1%) pendant une certaine durée pour les éliminer sans causer de dégât à l’œuvre ni laisser de résidus toxiques. Cette technique souffre toutefois de deux inconvénients majeurs. Le premier concerne l’importante durée de traitement nécessaire et le second concerne la sensibilité des résultats à un grand nombre de paramètres environnementaux. Cette étude a pour but d’analyser l’impact des températures élevées comme moyen pour accélérer le traitement ainsi que d’établir des modèles de mortalité intégrant certain paramètres qui influencent l’efficacité du traitement en vue de faciliter la détermination de la durée de ce dernier. Cette étude est réalisée en collaboration avec l’Institut Royal du Patrimoine Artistique (IRPA), et a également pour but de leur fournir un protocole permettant d’assurer une efficacité de traitement proche de 100%. Il a été montré que, conformément à ce qui existe dans la littérature, la température, la durée de traitement et le poids initial des larves influencent significativement la probabilité de mortalité des larves soumises au traitement tandis que le fait que la larve se situe dans une boite de Pétri ou dans une planchette de bois ne joue pas de rôle significatif. Il est également mis en évidence que, si la déshydratation des insectes lors du traitement joue un rôle important sur la mortalité, ce n’est pas le seul mécanisme impliqué. Des recherches supplémentaires sont nécessaires à ce sujet. Des modèles ont également pu être établis et ils permettent de déterminer qu’à température ambiante et 50% d’humidité du flux de gaz, la durée de traitement nécessaire pour éliminer 99% des insectes est de 26 jours [less ▲]

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See detailImpacts of Plant Growth-Promoting Rhizobacteria on Wheat Growth under Greenhouse and Field Conditions
Nguyen, Minh ULg; du Jardin, Patrick ULg; Jijakli, Haissam ULg et al

Poster (2015, June 16)

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for ... [more ▼]

Plant Growth-Promoting Rhizobacteria (PGPR) are well-known on stimulating root growth, enhancing mineral availability, and nutrient use efficiency in crops, and therefore become promising tool for sustainable agriculture. The aim of this project is to screen PGPR strains to enhance wheat growth and yield in combination with an optimised nitrogen (N) fertilizer dose, and thus finally reduce the use of N fertilizer with equivalent yield as the recommended N dose. A list of PGPR has been collected, including (1) Mix1 (a mix of Azospirillum sp., Azorhizobium sp., and Azoarcus sp.), (2) Mix2 (a mix of Mix1 plus with two strains phosphorus-solubilizing Bacillus sp.), (3) Bacillus amyloliquefaciens a, (4) Bacillus subtilis, and (5) Bacillus amyloliquefaciens b. The PGPR were screened in both greenhouse and field condition 2014. There was significant increase in root dry weight and in root per shoot ratio of plants inoculated with Mix1 in the greenhouse. Under field condition, besides the first factor PGPR, an additional factor, i.e. four N fertilizer doses, was applied in the combination with PGPR. Without or at low N fertilizer doses, the results showed that the grain yield declined significantly. The highest grain yield increase was fifteen per cent above the control and achieved by inoculating Bacillus subtilis without application of N fertilizer. However, there was statistically insignificant in all treatments due to variability between plot replicates. Based on these results, a modified protocol plus new strategies for PGPR selection has been built up for 2015 trial to reduce the influence of variability on field and possibly achieve the higher yield increase. [less ▲]

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See detailMicrobial diversity and function during different bioremediation strategies of diesel-polluted soil
Masy, Thibaut ULg; Hiligsmann, Serge ULg; Thonart, Philippe ULg et al

Poster (2015, June 16)

In numerous hydrocarbon-polluted sites, oxygen and pollutant bioavailability constitutes the main limiting factors for biodegradation because of the strong adsorption of hydrocarbons on organic soil ... [more ▼]

In numerous hydrocarbon-polluted sites, oxygen and pollutant bioavailability constitutes the main limiting factors for biodegradation because of the strong adsorption of hydrocarbons on organic soil particles (clay and peat). Therefore, several strategies such as biostimulation (with air/H2O2 and/or nutrients) or bioaugmentation are used, but often without understanding the endogenous microflora degrading capacity. This lack of differentiation between indigenous and added microorganisms could lead to poor predictability of the biodegradation efficiency. In addition, anaerobic degradation remains less applied in industrial settings for such compounds (especially for saturated hydrocarbons) as this process remains slow. In this context, the main objective of our study was to understand how the bacterial community evolves, in terms of species and degrading gene diversities, during the application of three different bioremediation strategies in a heavily diesel-polluted clay soil: (i) anaerobic natural attenuation, (ii) bioventing and (iii) bioaugmentation with Rhodococcus erythropolis T902.1. In addition to the supply of new degrading genes, bioaugmentation with this biosurfactant-producing strain should facilitate the bioassimilation of desorbed hydrocarbons by the whole degrading microflora. This hypothesis is strengthened by previous results obtained during several microcosm- and pilot-scale experiments. Aerobic and anaerobic microcosms were set up with three different soil samples coming from the same polluted site. Initially, their global organic content was identical but their hydrocarbon and peat concentrations were different, which led to differential oxygen consumption. Soils were sampled every 10 days to extract the DNA to measure changes in bacterial populations (with RISA analysis and 16S rRNA gene sequencing) and function (with qPCR and sequencing of degrading genes). Further analyses of the hydrocarbon content by GC-MS and of the genetic diversity by MiSeq metagenomic analysis provided detailed chemical and functional microbial data related to compound degradation and relative gene increases. Initial results showed significant differences in the microbial community structure. Moreover, Rhodococci seem to be maintained in the soil after inoculation. [less ▲]

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See detailComparative effects of freeze-drying, fluidized bed-drying and heat moisture treatment on the in vitro digestibility of dry matter, starch and protein of corn grain
Odjo, Djosse Psijus Sylvanus ULg; Malumba Kamba, Paul ULg; Migan, Sabé et al

Poster (2015, June 15)

There is some evidence that the chemical composition and nutritional value of corn is variable and may be influenced by heat treatment. This study compares the modifications induced by freeze-drying (as ... [more ▼]

There is some evidence that the chemical composition and nutritional value of corn is variable and may be influenced by heat treatment. This study compares the modifications induced by freeze-drying (as control), fluidized-bed drying and heat-moisture treatment (at 54, 90 and 130°C) of a flint corn grain and flour harvested at two different moisture content (33 and 28%, wet basis) on its digestibility assessed through in vitro methodologies. High temperature applied during fluidized-bed drying and heat-moisture treatment lead to the increase of the in vitro digestibility of dry matter. This is associated to a partial gelatinization of corn starch granules during heat treatments making them more suitable for digestion by porcine pancreatic amylase. This assumption is demonstrated by the increase of the in vitro digestibility of starch recorded with the increase of drying and heat-treatment temperature. It must be noted however, that at the same time, the digestibility of corn proteins decreased, probably because of denaturation undergo by proteins during heat treatment. It seems that there is an interaction between digestion of starch and protein, the corn starch granule being tightly embedded in a protein matrix. The extent of all of these phenomena strongly depends on availability of water which play a key but non clear role in the effect thermal history of corn grain in its nutritive value. [less ▲]

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See detailIn vitro evaluation of an anti-apoptotic drug, Z-VAD-FMK, for further use in ovarian tissue transplantation
Fransolet, Maïté ULg; HENRY, Laurie ULg; LABIED, Soraya ULg et al

Poster (2015, June 14)

Study question: In a model reproducing early ischemia after ovarian tissue transplantation, does the pan-caspase inhibitor Z-VAD-FMK could prevent granulosa cell apoptosis? Summary answer: Results ... [more ▼]

Study question: In a model reproducing early ischemia after ovarian tissue transplantation, does the pan-caspase inhibitor Z-VAD-FMK could prevent granulosa cell apoptosis? Summary answer: Results obtained with HGL5 granulosa cell line suggest that Z-VAD-FMK is efficient to protect granulosa cells from etoposide or CoCl2 induced apoptosis. What is known already: Removal, cryopreservation and subsequent graft of ovarian strips after cancer treatment have been successfully used to re-establish female fertility. However, the pregnancy rate after autografting of cryopreserved tissue is about 30%. Indeed, the major problem after transplantation is follicular loss due to ischemic reperfusion injury. Study design, size, duration: Three human granulosa cell lines (GC1a, HGL5 and COV434) were cultured during 48h with Z-VAD-FMK with or without etoposide to induce apoptosis. To reproduce the ischemic phase of the graft, cells were cultured without serum under reduced O2 (1%) or with CoCl2 (chemical hypoxia). Participants/materials, setting, methods: Granulosa cells were used as a model since they are essential for oocyte survival. Metabolic cell activity was evaluated by the WST-1 assay. Cell apoptosis was analyzed by flow cytometry after annexin V-FITC and propidium iodide double staining. The mRNA levels and protein expression of apoptotic markers were evaluated using RT-qPCR and western blot analysis. Main results and the role of chance: Flow cytometry showed that cells co-treated with etoposide and Z-VAD-FMK displayed a higher percentage of viable cells as compared to etoposide alone. When in vivo ischemic stage was mimicked (1% O2), no beneficial effect of the Z-VAD-FMK was detected. However, a significant decrease of the number of early apoptotic cells was evidenced by flow cytometry for HGL5 cells treated with Z-VAD-FMK. RT-qPCR and western blot analysis revealed that apoptotic molecules were not modulated. Metabolic activity of the 3 cell lines was reduced by CoCl2. For HGL5 cells, this decrease was partially reversed by Z-VAD-FMK. The number of viable cells was reduced by CoCl2 in HGL5 cells but Z-VAD-FMK allowed to preserve a similar number of viable and apoptotic cells than in control condition. Limitations, reasons for caution: In this study we used 3 different cell lines but granulosa cells represent only a part of the cell types present in ovarian tissue biopsies. Experiences on the effect of Z-VAD-FMK on primary culture of granulosa cells have not yet been realized. Wider implications of the findings: This study suggests that the use of an antiapoptotic drug could be efficient to improve ovarian tissue transplantation outcomes. Ovarian tissue grafting studies using our xenograft murine model will be performed to test the potential efficacy of this drug to improve tissue viability and primordial follicles preservation after transplantation. [less ▲]

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See detailStudying the great potential of cultivable bacteria associated with the brown alga Ascophyllum nodosum
Martin, Marjolaine ULg; Martin, Renée ULg; Barbeyron, Tristan et al

Poster (2015, June 09)

Bacteria associated with algae differ markedly from those living freely in seawater and represent great potential for the production of diverse bioactive compounds as they interact in multiple complex ... [more ▼]

Bacteria associated with algae differ markedly from those living freely in seawater and represent great potential for the production of diverse bioactive compounds as they interact in multiple complex ways with their host. Here we identified new bacterial species, and their polysaccharolytic activities, associated with the brown alga Ascophyllum nodosum. To isolate cultivable microorganisms, algal thalli of Ascophyllum nodosum were swabbed with sterile cotton tips and marine agar plates were inoculated. Three-hundred isolated bacteria were screened for agarase, kappa- or iota-carrageenase activities on specific marine media. Thirty-two bacteria with polysaccharolytic activities were isolated and a part of their 16S rDNA (8F-1492R) were amplified and sequenced. Twenty-seven were classified as Flavobacteriia and five as Gammaproteobacteria. Putative new strains and species of Zobellia, Maribacter, Cellulophaga, Shewanella, Glaciecola, Pseudoalteromonas and Colwellia were identified by phylogenetic analysis. Genomics libraries with their DNA were constructed in Escherichia coli and Bacillus subtilis and are currently screened for diverse enzymatic activities (agarases, iota-and kappa-carrageenases, cellulases, beta-glucosidases, sulfatases and amylases). In an era where high throughput sequencing is mostly used to study bacterial communities, cultivation methods are underestimated. Here, we revealed that only ten percent of the cultivable bacteria on this brown alga could degrade algal polysaccharides, which lead to asking us; who and what are the 90 other percents doing there? Furthermore, by this cultivation method we could also identify putative new bacterial strains/species, which are screened for polysaccharidases. Novel glycoside hydrolases from unknown marine bacteria represent great biotechnological potential as they should have original industrial properties. [less ▲]

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See detail‘Ex-situ’ preservation and characterization of Antarctic cyanobacteria in the BCCM/ULC collection
Kleinteich, Julia ULg; Renard, Marine ULg; Simons, Véronique et al

Poster (2015, June 09)

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. An ISO9001 certificate was obtained for the public deposition and distribution of ... [more ▼]

The BCCM/ULC public collection of (sub)polar cyanobacteria is funded since 2011 by the Belgian Science Policy Office. An ISO9001 certificate was obtained for the public deposition and distribution of strains, as part of the multi-site certification for the BCCM consortium. BCCM/ULC is currently holding 160 public cyanobacterial strains and the catalogue is available on http://bccm.belspo.be/catalogues/ulc-catalogue-search. Continuous maintenance of living cultures, some of which are also cryopreserved, ensure the preservation and the possibility to rapidly deliver strains to clients for fundamental and applied research. The main holding of the collection concerns (sub)polar strains isolated from different biotopes and representative of a large taxonomic diversity. The molecular characterization is underway, on the basis of 16S rRNA and ITS sequences, but also Multiple Locus Sequence Analysis and genome sequencing. In addition, cyanobacteria are known to produce a range of secondary metabolites (e.g. alkaloides, cyclic and linear peptides, polyketides) with various bioactive potential. The presence of genes involved in the production of microcystin is currently studied by PCR, and analytical methods are used to confirm the toxin production. Due to the geographic isolation and the strong environmental stressors of the habitat, the exploration of these metabolites in Antarctic cyanobacterial strains seems especially promising for biotechnology or biomedical applications. [less ▲]

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See detailExpression study of FRD3 in Arabidopsis relatives
Scheepers, Maxime ULg; Charlier, Jean-Benoit ULg; Spielmann, Julien ULg et al

Poster (2015, June 08)

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene ... [more ▼]

Transcriptomic studies identified genes which are constitutively over-expressed in A. halleri compared to A. thaliana and which may have a role in metal tolerance or accumulation (1-3). A candidate gene encodes FRD3, a member of the MATE family of membrane transporters (56 members in A. thaliana). It is a citrate transporter involved in iron homeostasis (4-6) and playing a role in zinc tolerance in A. thaliana (7). We are aiming to analyse the FRD3 high expression in A. halleri and the FRD3 function in zinc and iron homeostasis in A. thaliana. [less ▲]

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See detailCharacterization of YbjG, a pyrophosphate phosphatase from E. coli involved in the lipid carrier undecaprenyl phosphate metabolism
Delbrassine, François ULg; Auger, Rodolphe; El Ghachi, Meriem ULg et al

Poster (2015, June 08)

•Background Undecaprenyl phosphate (C55-P) is an essential lipid carrier involved in the biosynthesis of cell surface carbohydrate polymers such as the peptidoglycan. C55-P is the result of the ... [more ▼]

•Background Undecaprenyl phosphate (C55-P) is an essential lipid carrier involved in the biosynthesis of cell surface carbohydrate polymers such as the peptidoglycan. C55-P is the result of the dephosphorylation of the undecaprenyl pyrophosphate (C55-PP) by specific phosphatases. In Escherichia coli this dephosphorylation can be performed by four integral membrane proteins, BacA, and three members of the type 2 phosphatidic acid phosphatase family (PAP2), PgpB, YbjG, and LpxT. •Objectives The aim of this project is to characterize YbjG and contributes to the understanding of the physiological role and mechanism of action of this enzyme in the C55-P metabolism. The C55-PP phosphatases could become an interesting target in the search for new molecules with antibacterial activity. •Methods In parallel the stability of YbjG and its activity against C15-PP were assessed in 94 different detergents. Moreover the enzymatic activity of YbjG was studied: substrate specificity, optimum pH and temperature, effect of detergent concentration. •Conclusions For the first time, YbjG has been purified and we show its ability to dephosphorylate C15-PP, DGPP and C55-PP in vitro with respectively decreasing efficiency. No activity has been detected on five other potential substrates (PPi, PA, C5-PP, G6P & PNPP). The phosphatase activity on C15-PP is maximum at pH 6,5 and 25 °C. Moreover Cymal6, LMNG, & ωUDM are good detergent both for the stability and the C15-PP phosphatase activity of YbjG, but approximately half of the 94 tested detergents show C15-PP phosphatase activity on the qualitative enzymatic test. [less ▲]

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See detailTowards the identification of mechanisms underlying the high expression of HMA4, an essential gene for zinc hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Poster (2015, June 08)

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and ... [more ▼]

To maintain metal homeostasis within physiological limits independently of metal concentrations present in soil, plants developed a complex network including metal uptake, chelation, trafficking, and storage processes. In this network, transporters have a central role. To study the molecular basis of zinc homeostasis in plants, we are using A. halleri, a zinc- and cadmium-tolerant and zinc-hyperaccumulating species representing the extreme end of natural variation in terms of metal homeostasis. Indeed, A. halleri stores high amount of metals in vacuoles of above-ground tissues (>1% Zn or 0.01% Cd in shoot dry weight). Cross-species transcriptomic studies identified about thirty genes which are constitutively over-expressed in A. halleri compared to its non-tolerant and non-hyperaccumulator sister species, Arabidopsis thaliana (1-3). HMA4 is one of these genes. It encodes a Zn/Cd plasmamembrane pump involved in xylem loading/unloading which is a key step in the hyperaccumulation process (4-5). The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies (5). We aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. [less ▲]

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See detailA lysine cluster in domain II of Bacillus subtilis PBP4a plays a role in the membrane attachment of this C1 PBP.
Vanden Broeck, Arnaud; Dauvin, Marjorie ULg; Sauvage, Eric et al

Poster (2015, June 08)

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them: K86, K114 ... [more ▼]

Bacillus subtilis PBP4a belongs to the class-C1 PBPs characterized by two internal additional domains of unknown function. Seven lysine residues (K) are protruding from domain II. Four of them: K86, K114, K119 and K265 have been mutated in glutamine residues (Q). Both proteins (WT and Mut4KQ PBP4a) have been produced without signal peptide in E. coli and their sub-cellular localizations determined by measuring the DD-carboxypeptidase activities in the different compartments (cytoplasmic vs membrane attached proteins). After purification, their binding to B. subtilis membranes has been compared: WT PBP4a interacts in vitro with membranes isolated from this organism in contrast to Mut4KQ PBP4a that remains entirely unbound. In absence of any amphiphilic peptide in PBP4a, the crown of positive charges on the surface of domain II is likely responsible for the PBP cellular localization in interaction with the cytoplasmic membrane. [less ▲]

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See detailUNRAVELLING THE ROLES OF LYSINE ACETYLATION BY ELP3 DURING INNER EAR DEVELOPMENT
Mateo Sanchez, Susana ULg; Delacroix, Laurence ULg; Freeman, Stephen ULg et al

Poster (2015, June 06)

Given the importance of acetylation homeostasis in controlling developmental processes [1-3], we planned to investigate its role in inner ear formation and focused our attention on Elp3 acetyl-transferase ... [more ▼]

Given the importance of acetylation homeostasis in controlling developmental processes [1-3], we planned to investigate its role in inner ear formation and focused our attention on Elp3 acetyl-transferase, a member of the Elongator complex recently implicated in neurogenesis [4]. To determine the role of Elp3 in the inner ear, we first analysed the spatio-temporal pattern of ELp3 mRNA expression and showed that it was expressed in the entire early otocyst at E11.5 and persisted later in the sensory epithelium of the cochlea (the organ of Corti), in the spiral ganglion, in the stria vascularis and in the vestibule. To unravel in vivo functions of Elp3 in the inner ear, we used conditional knock-out mice in which Elp3 gene is deleted from early otocyst (Elp3 cKO). We submitted these mice to a battery of vestibular testing (i.e. stereotyped circling ambulation, head bobbing, retropulsion, and absence of reaching response in the tail-hanging test) and found significant abnormalities. Besides, the auditory brain stem response of Elp3 cKO indicated that these mice are severely deaf. At the cellular level, we did not find any structural abnormalities nor cell patterning defects that could explain deafness or balance dysfunction in Elp3 cKO mice. However, we detected some defaults in the planar orientation of their auditory hair cell bundle. We were also able to demonstrate an increased level of apoptosis in the Elp3 cKO spiral ganglion at E14.5 leading to a reduced number of neurons and fibers innervating the cochlear hair cells as well as a reduced number of their synaptic ribbons at P15. Moreover, the remaining spiral ganglion neurons extend processes showing clearly defects regarding hair cells innervation (misorientation of fibers). In conclusion, our results clearly show a role for Elp3 both in hearing and balance. We plan to go deeper in the mechanisms involved through the identification of the proteins that are targeted for acetylation by Elp3. [less ▲]

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See detailCXCR7/ACKR3 is activated by chemokines from both CXC and CC subfamilies
Szpakowska, Martyna ULg; Counson, Manuel; Beaupain, Nadia et al

Poster (2015, June 05)

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See detailSpatio-temporal dynamics of β-tubulin isotypes and acetyl-alpha tubulin during the development of the sensory auditory organ in rodents.
Renauld, Justine ULg; Thelen, Nicolas ULg; Johnen, Nicolas ULg et al

Poster (2015, June 05)

The auditory organ is a highly specialized structure composed by specific cellular types. The sensory cells are characterized by stereocilia at their apex and are necessary for the sound perception. These ... [more ▼]

The auditory organ is a highly specialized structure composed by specific cellular types. The sensory cells are characterized by stereocilia at their apex and are necessary for the sound perception. These cells are supported by supporting cells. Supporting cells possess a characteristic cytoskeleton in direct relation with their morphological features and their development. There are different β-tubulin isoforms in microtubules of vertebrate tissues. However, their functional significance is still largely unknown. In the present study, we investigated the localization of five β-tubulin isotypes (β 1 to 5) as well as acetyl-α-tubulin within the hearing organ during development in rodents. By using confocal microscopy, we showed that with the exception of the β3-tubulin isoform that was specific to nerve fibres, all the different β-tubulin isoforms and acetyl-α-tubulin were mainly present in the supporting cells. Contrary to β1-4-tubulins, we also found that the β5-tubulin isoform appeared only at a key stage of the postnatal development in specific cell types (pillar cells and Deiters’ cells). By using transmission electron microscopy, we revealed further that this developmental stage coincided with the formation of two separate bundles of microtubules from a unique one in these supporting cells. In conclusion, these results suggest that the β5-tubulin isoform might be involved in the generation of new microtubule bundles from a pre-existing one. [less ▲]

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See detailDesign and synthesis of PET-probes targeting AMPA-subtype receptors
Deverdenne, François ULg; Claes, Giselle ULg; Goffin, Eric ULg et al

Poster (2015, June 05)

The AMPA subtype of glutamatergic receptors is the main actor in the excitatory neurotransmission in the mammalian central nervous system. These receptors are involved in the expression and the ... [more ▼]

The AMPA subtype of glutamatergic receptors is the main actor in the excitatory neurotransmission in the mammalian central nervous system. These receptors are involved in the expression and the maintenance of the long-term potentiation, a phenomenon closely linked to cognitive and memorization processes. Based on experimental data collected in recent years, the use of AMPA potentiators seems to be an interesting approach in the treatment of cognitive deficits (e.g. Alzheimer disease), schizophrenia or depression. Such AMPA signal potentiation could be mediated by positive allosteric modulators (PAMs) of the AMPA receptors, a class of compounds able to produce a fine signal tuning in the presence of the endogenous ligand in the synapse, providing less toxicity than direct agonists. With this approach, the laboratory of Medicinal Chemistry of Liège university developed many series of AMPA potentiators , among which 1,2,4-benzothiadiazine 1,1-dioxides (BTDs). In order to better understand the in vivo mapping of AMPA receptors and its evolution in neurological diseases, the present work aims at developing the design and the synthesis of BTDs positive allosteric modulators radiolabeled with a fluorine-18 atom. Based on previously synthesized series in this field, we investigate the synthesis of a new class of high-affinity AMPA potentiators characterized by the presence of a fluorine atom at selected positions on the structure of the AMPA potentiators. Thanks to in vitro pharmacological evaluations, we will further determine the best candidates for their fluorine-18 radiolabeling. [less ▲]

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See detailSimulations of the auroral signatures of Jupiter’s magnetospheric injections
Dumont, Maïté ULg; Grodent, Denis ULg; Radioti, Aikaterini ULg et al

Poster (2015, June 04)

Jupiter’s ultraviolet auroral emissions are divided into four main components: the polar emissions, the main emission, the satellite footprints and the outer emissions. The morphology of the outer ... [more ▼]

Jupiter’s ultraviolet auroral emissions are divided into four main components: the polar emissions, the main emission, the satellite footprints and the outer emissions. The morphology of the outer emissions can be either diffuse, arc-shaped or compact emissions. In the present study, we focus on outer emissions clearly detaching from the main emission and forming compact structures that are evolving regardless of the rest of the auroral emission. These auroral features were selected because they have the same appearance as the auroral signature of a clearly identified injection previously observed by Mauk et al. [2002] at Jupiter, based on simultaneous Galileo spacecraft and Hubble Space Telescope measurements. Here, we report on the evolution of those ultraviolet auroral features appearing in Hubble Space Telescope images of the northern and southern Jovian hemispheres. We investigate the possibility that those ultraviolet auroral structures are associated with energetic particle injections. For this study, we analyze the temporal variations of the longitudinal extent and of the brightness of the auroral structures. Indeed, the injected charged particles drift at different rates due to energy-dependent gradient and curvature drifts, which leads to an increase with time of the longitudinal extent of the feature and of its associated auroral signature. Since the injected energy follows the same trend, the brightness decreases with time. Different processes can generate auroral signatures of plasma injections. We simulate them by considering that pitch angle diffusion is generated by the precipitating energy flux in the ionosphere and whistler-mode waves through electron scattering. We compare the characteristics of the simulated signature with the observed parameters. Following this comparison, we are able to test whether the aforementioned mechanism is responsible for the auroral emission and to infer the typical energy and the spectral index of the energy distribution of the electrons involved in the injection process. [less ▲]

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See detailCritical periods and critical values explaining fluxes inter-annual variability in a temperate mixed forest
Hurdebise, Quentin ULg; Vincke, Caroline; De Ligne, Anne ULg et al

Poster (2015, June 04)

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the ... [more ▼]

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the regression between annual NEE and cumulated NEE on a mobile window. •Identification of critical values of a threshold used to decompose annual and seasonal NEE in two components. [less ▲]

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See detailThe Main Auroral Emission at Jupiter: Altitude profile and Dawn-Dusk Asymmetry
Bonfond, Bertrand ULg; Gustin, Jacques ULg; Gérard, Jean-Claude ULg et al

Poster (2015, June 04)

The main auroral emission at Jupiter generally forms a quasi-continuous curtain around each magnetic poles. This emission magnetically maps to the middle magnetosphere and is related to the corotation ... [more ▼]

The main auroral emission at Jupiter generally forms a quasi-continuous curtain around each magnetic poles. This emission magnetically maps to the middle magnetosphere and is related to the corotation enforcement of the plasma originating from the volcanic satellite Io. The first models of corotation enforcement current system at Jupiter assumed symmetry around the magnetic axis. However, observations and further development of these models outlined the importance of local time variability of such currents. In this presentation, we show the results of two studies of this local time variability relying on the large dataset of Far-UV observations from the Hubble Space Telescope (HST). Knight’s theory of field aligned current predicts that the auroral precipitating energy flux and the energy of the precipitating electrons are correlated. Since the altitude of the auroral emissions decreases as the energy increases, it is thus expected that the altitude of the auroral brightness peak varies as a function of the local time following the variations of the field aligned currents. We compare the altitude of the main emission on the post-dusk side as seen in the visible domain by Galileo’s Solid State Imager and the same altitude for the night side as seen by the Advanced Camera for Surveys (ACS) on board HST in the Far-UV domain. We show some significant differences between the two data sets. Unfortunately, a careful analysis involving both spectral observations and simulations indicates that the Far-UV vertical profiles are hampered by observational ambiguities due to absorption by hydrocarbon molecules. Only additional and judiciously designed new observations could reveal the actual amount of methane along the line of sight. The second study consists in a comparison of the emitted power in local time sectors corresponding to dawn and dusk. Results in the northern hemisphere are difficult to interpret because the magnetic anomaly probably causes a decrease of the auroral brightness in regions of strong magnetic field. In the southern hemisphere, where the field magnitude is more uniform along the main oval, the dusk sector is ~3 times brighter than the dawn sector. In accordance with measurements of magnetic field divergence in the equatorial plane by Galileo, these results suggest the presence of a partial ring current in the night side of the magnetosphere with upward currents in the dawn side and downward currents in the dusk side. [less ▲]

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See detailImpact of biomaterial physical characteristics on bone regeneration: Comparison of three hydroxyapatites
LAMBERT, France ULg; Bacevic, Miljana ULg; Schupbach, P et al

Poster (2015, June 03)

Bone regeneration biomaterials with identical chemical compositions are frequently considered by clinicians as similar. However, the clinical performance of regenerative biomaterial may be influenced by ... [more ▼]

Bone regeneration biomaterials with identical chemical compositions are frequently considered by clinicians as similar. However, the clinical performance of regenerative biomaterial may be influenced by other parameters such as topographical properties. [less ▲]

Detailed reference viewed: 16 (3 ULg)
See detailPolyplex Based on Polycarbonate Polymers for an Efficient Delivery of HDAC5 and HDAC7 siRNA
Frère, Antoine ULg; Tempelaar, Sarah; Peulen, Olivier ULg et al

Poster (2015, June 02)

Detailed reference viewed: 17 (5 ULg)
See detailEx Parrot: The Aarhus-Sydney gamma Dor experiment on pulsations and rotation
Antoci, V.; Ouazzani, R.; Murphy, S. et al

Poster (2015, June 01)

γ Doradus stars, exhibiting pure gravity modes pulsations, occupy the region between the solar-like oscillators and the delta Sct stars in the HRD. The Kepler mission delivered data of unprecedented ... [more ▼]

γ Doradus stars, exhibiting pure gravity modes pulsations, occupy the region between the solar-like oscillators and the delta Sct stars in the HRD. The Kepler mission delivered data of unprecedented quality spanning up to 4 years, allowing to resolve closely spaced modes to measure, e.g., period spacings and to infer internal rotation profiles. Here we present an ensemble study of all γ Doradus stars observed with the Kepler mission. We investigate among others the range of excited modes, their amplitudes and the impact of rotation on these quantities. Our aim is to better understand the pulsation excitation as well as the mode selection mechanism in these stars. Our results may help to also explain the lack of solar-like oscillators exhibiting g-modes pulsations on the main sequence, although the instability domains of γ Doradus and solar-like stars overlap. [less ▲]

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See detailBIOREFINE Project – Recovery of useful nutrients from organic wastes produced in five European countries (3AV.3.55)
Tarayre, Cédric ULg; De Clercq, Lies; Michels, Evi et al

Poster (2015, June 01)

At this time, many wastes are used or eliminated through processes that do not really consider their potential applications. Such wastes contain useful nutrients (nitrogen, phosphorus and potassium), the ... [more ▼]

At this time, many wastes are used or eliminated through processes that do not really consider their potential applications. Such wastes contain useful nutrients (nitrogen, phosphorus and potassium), the importance of which has been demonstrated in agriculture for many years. The composition of wastes is highly heterogeneous, which makes treatment techniques more difficult to apply on a large scale. Sewage sludge is usually used as a fertilizer in agriculture, in energy production or in the field of construction. The main use of manure is agriculture, although considerable amounts of nutrients are lost and cause pollution. Digestate is also used in agriculture, but other alternatives have been proposed. Ashes should also be highlighted, although they do not contain nitrogen, which is lost into the atmosphere during the combustion process. Finally, household and industrial wastes are resources that should be considered as well. Those different types of wastes could be recycled to produce environment-friendly fertilizers. Here, we propose to investigate these opportunities inside five European countries (Belgium, France, Germany, United Kingdom and The Netherlands) through five work packages with the BioRefine Project. [less ▲]

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See detailWhat can we learn from asteroseismology of beta Cephei stars?
Salmon, Sébastien ULg; Montalban, J.; Miglio, A. et al

Poster (2015, June 01)

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See detailHubble Space Telescope observations of variation of the O I 135.6 nm/ O I 130.4 nm ratio in Ganymede’s atmosphere
Molyneux, P. M.; Nichols, J. D.; Bannister, N. P. et al

Poster (2015, June)

We present new high-sensitivity HST/COS measurements of the atmospheric O I 135.6 nm/ O I 130.4 nm ratio at Ganymede, which we show exhibits significant spatial and temporal variability. Specifically, the ... [more ▼]

We present new high-sensitivity HST/COS measurements of the atmospheric O I 135.6 nm/ O I 130.4 nm ratio at Ganymede, which we show exhibits significant spatial and temporal variability. Specifically, the ratios observed on Ganymede’s leading hemispheres vary between 2.14±0.03 and 2.67±0.02, while on the trailing hemisphere the ratios are observed to be between 0.98±0.02 and 1.53±0.03. These high-sensitivity observations increase the signal to noise of these measurements by an order of magnitude over previous HST/STIS observations of the same [1], thus confirming that the temporal variation suggested by these previous observations is real. The emissions are excited through electron-impact excitation of Ganymede’s oxygen atmosphere by electrons which are locally accelerated within its magnetosphere [2,3]. The variation in the ratio magnitude may be explained either by variations in the ratio of atomic to molecular oxygen in the atmosphere or by a change in the temperature of the electrons exciting the emissions. An increase in the proportion of molecular oxygen acts to increase the ratio, as does a cooler electron temperature.References [1] Feldman, P. D., McGrath, M. A., Strobel, D. F., Moos, H. W., Retherford, K. D. and Wolven, B. C., HST/STIS ultraviolet imaging of polar aurora on Ganymede, Astrophys. J., Vol. 535, pp. 1085-1090, 2000. [2] Hall, D. T., Feldman, P. D., McGrath, M. A. and Strobel, D. F., The far-ultraviolet oxygen airglow of Europa and Ganymede, Astrophys. J., Vol. 499, pp. 475-481, 1998. [3] Eviatar, A., Strobel, D. F., Wolven, B. C., Feldman, P. D., McGrath, M. A. and Williams, D. J., Excitation of the Ganymede ultraviolet aurora, Astrophys. J., Vol. 555, pp. 1013-1019, 2001. [less ▲]

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See detailCross-modal identification of six subregions within the left PMd and their functional characterization
Genon, Sarah ULg; Li, Hai; Fan, Lingzhong et al

Poster (2015, June)

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See detailThe class IIa HDACs prevent degradation of RBFOX2 by Chaperone-Mediated Autophagy
Detiffe, Cécile ULg; Dequiedt, Franck ULg; Rambout, Xavier ULg

Poster (2015, June)

By modulating the acetylation level of histones, histone deacetylases (HDACs) are enzymes playing a key role in the control of gene expression. In addition to histones, HDACs also have non-histone ... [more ▼]

By modulating the acetylation level of histones, histone deacetylases (HDACs) are enzymes playing a key role in the control of gene expression. In addition to histones, HDACs also have non-histone substrates, which may relate to potential roles for HDACs outside of gene regulation. Because HDACs are key regulators of major cellular processes such as cell division, apoptosis and differentiation, it is not surprising that these enzymes have emerged as attractive therapeutic targets for cancer. While the in vivo antitumoral activities of several small molecules HDACs inhibitors have generated a lot of hope, these molecules often showed dramatic side-effects. It is suspected that these side effects could be related to unknown functions of HDACs. The goal of this project is to identify novel, unsuspected functions of HDACs that will help developing more efficient and specific HDAC-based antitumoral therapies. To identify novel functions of HDACs, we used a high-throughput yeast two hybrid (Y2H) approach. This led to the first comprehensive interactomic map of class IIa HDACs that includes 84 protein partners. Among new HDACs partners, we identified several RNA-binding proteins (RBPs) involved in mRNA processing. In this work, we focused on one, the alternative splicing regulator RBFOX2, and investigated its regulation by class IIa HDACs. Through various approaches, we verified that HDAC7 interacts with RBFOX2. In addition, we found that silencing of HDAC7 correlates with a decrease in stability of RBFOX2. Because we identified a potential CMA-specific KFERQ motif in RBFOX2, we tested the possibility that RBFOX2 might be degraded through Chaperone-Mediated Autophagy (CMA). Supporting this hypothesis, we found that RBFOX2 interacts with the co-chaperone HSC70. RBFOX2 levels are sensitive to CMA inducers, including serum starvation and 6AN. Interestingly, we found that a lysine residue in the KFERQ motif of RBFOX2 is acetylated, suggesting that HDAC7 might control RBFOX2 degradation through reversible acetylation. Indeed, degradation of RBFOX2 following HDAC7 silencing was reverted with an inhibitor of autophagy, bafilomycin A1. Analysis of RNA splicing pattern in cells depleted for HDAC7 showed that absence of HDAC7 is associated with 159 alternative splicing events. These events mostly include exon skipping that is known to be the major splicing event in which RBFOX2 is involved. In addition, we observed a highly statistically overlap between splicing events associated with RBFOX2 and HDAC7 depletion. [less ▲]

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See detailDeciphering the metabolism of polyprenyl-phosphate: The universal glycan lipid carrier at the membrane frontier
Manat, Guillaume; Roure, Sophie; El Ghachi, Meriem ULg et al

Poster (2015, June)

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See detailGenetic depletion of the dual specificity protein phosphatase DUSP3 promotes LLC Lung tumour metastasis
Vandereyken, Maud ULg; Amand, Mathieu; Van Overmeire, Eva et al

Poster (2015, June)

DUSP3, also called Vaccinia-H1 Related (VHR) is a small dual specificity phosphatase dephosphorylating both tyrosine and serine/threonine phosphorylated residues. DUSP3 plays an important role in cell ... [more ▼]

DUSP3, also called Vaccinia-H1 Related (VHR) is a small dual specificity phosphatase dephosphorylating both tyrosine and serine/threonine phosphorylated residues. DUSP3 plays an important role in cell cycle regulation and is up-regulated in several human cancers. The physiological role of this phosphatase is, however, poorly understood. We have recently generated a DUSP3 knockout mouse by homologous recombination. The obtained mice have no spontaneous phenotype or pathology. However, DUSP3 deficiency prevented neo-vascularization of subcutaneously transplanted Matrigel plugs and Lung Lewis Carcinoma (LLC) tumours, suggesting an involvement of DUSP3 in tumour angiogenesis. Considering the importance of angiogenesis in metastatic formation, our study aimed to investigate the role of DUSP3 in metastatic dissemination. To do so, we used the LLC experimental metastasis model that shortcuts the intravasation/extravasation processes by injecting intravenously the LLC and the B16 (metastatic melanoma cell line) cells. Surprisingly, LLC, but not B16, lung metastasis developed twice faster in DUSP3-KO than WT mice. The enhanced LLC metastatic growth in DUSP3-/- mice was transferable to WT mice via DUSP3-/- bone marrow adoptive transfer, suggesting an involvement of the hematopoietic compartment in the observed phenotype. This was confirmed by a higher infiltration of neutrophils and macrophages in the lungs of DUSP3-KO compared to WT mice after LLC injection. This infiltration was correlated with higher expression of the chemokine receptor CCR2 in LLC-bearing DUSP3-KO lungs macrophages. Interestingly, LLC, but not B16 cells, were found to secrete high level of CCL2/MCP1, the CCR ligand chemokine. In line with this observation, we found that DUSP3-/- bone marrow derived-macrophages have a higher migration potential in response to LLC, but not B16, -conditionned medium. Altogether, our results suggest that DUSP3 plays an important role in metastatic dissemination/growth by a mechanism involving the control of CCR2-CCL2 chemoattraction axis in macrophages. [less ▲]

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See detailComparison of PLS and SVM discriminant analysis for NIR hyperspectral data of wheat roots in soil
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

Poster (2015, June)

The aim of this work was to compare the chemometric tools PLS and SVM on near infrared spectra in order to reach the most accurate discrimination between spectra of soil, root and crop residues of winter ... [more ▼]

The aim of this work was to compare the chemometric tools PLS and SVM on near infrared spectra in order to reach the most accurate discrimination between spectra of soil, root and crop residues of winter wheat on hyperspectral images. [less ▲]

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See detailStudy of N-linked glycosylation in different life stages of the red flour beetle (Tribolium castaneum)
Smargiasso, Nicolas ULg; Walski, Tomasz; Van Damme, Els et al

Poster (2015, June)

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See detailThe mysteries of droplet birth in microfluidic cross junctions
Van Loo, Stéphanie ULg

Poster (2015, June)

In microfluidics flow focusing is widely used to produce water-in-oil droplets in microchannels at high frequency. Nevertheless, the scaling laws associated to droplet length, speed and frequency could ... [more ▼]

In microfluidics flow focusing is widely used to produce water-in-oil droplets in microchannels at high frequency. Nevertheless, the scaling laws associated to droplet length, speed and frequency could not be identified yet, owing to the large number of parameters involved (incl. complex geometry). We here present an experimental study of droplet formation in a microfluidic cross-junction with a minimum number of geometrical parameters. We mostly focus on the dripping regime. The formation sequence is decomposed in two steps, inflation and squeezing, that vary differently according to both water and oil flow rates. These variations reveal several insights about the fluid flows in both phases. From there we infer the scaling law that relates droplet volume and frequency to the Capillary number associated to each inlet flow rate. This law involves a minimum of fitting parameters. We finally discuss the influence of inlet control (flow rate vs. pressure) and surfactants on the formation dynamics. [less ▲]

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See detailCoherent backscattering in the Fock space of a disordered Bose-Hubbard system
Engl, Thomas; Dujardin, Julien; Tisserond, Emilie et al

Poster (2015, June)

We predict a generic signature of quantum interference in many-body bosonic systems resulting in a coherent enhancement of the average return probability in Fock space [1]. This enhancement is robust with ... [more ▼]

We predict a generic signature of quantum interference in many-body bosonic systems resulting in a coherent enhancement of the average return probability in Fock space [1]. This enhancement is robust with respect to variations of external parameters even though it represents a dynamical manifestation of the delicate superposition principle in Fock space. It is a genuine quantum many-body effect which lies beyond the reach of any mean-field approach. Using a semiclassical approach based on interfering paths in Fock space, we calculate the magnitude of the backscattering peak and its dependence on gauge fields that break time-reversal invariance. We confirm our predictions by comparing them to exact quantum evolution probabilities in Bose-Hubbard models, and discuss their relevance in the context of many-body thermalization. We furthermore propose a specific experimental setup in order to detect this many-body coherent backscattering phenomenon with ultracold bosonic atoms. [1] T. Engl, J. Dujardin, A. Argüelles, P. Schlagheck, K. Richter, and J. D. Urbina, Phys. Rev. Lett. 112, 140403 (2014). [less ▲]

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See detailWhat are the determinants of the operational losses severity distribution ? A multivariate analysis based on a semiparametric approach.
Hambuckers, julien ULg; Heuchenne, Cédric ULg; Lopez, Olivier

Poster (2015, June)

In this paper, we analyse a database of around 41,000 operational losses from the European bank UniCredit. We investigate three kinds of covariates: firm-specific, fi- nancial and macroeconomic covariates ... [more ▼]

In this paper, we analyse a database of around 41,000 operational losses from the European bank UniCredit. We investigate three kinds of covariates: firm-specific, fi- nancial and macroeconomic covariates and we study their relationship with the shape parameter of the severity distribution. To do so, we introduce a semiparametric approach to estimate the shape parameter of the severity distribution, conditionally to large sets of covariates. Relying on a single index assumption to perform a dimension reduction, this approach avoids the curse of dimensionality of pure multivariate nonparametric techniques as well as too restrictive parametric assumptions. We show that taking into account variables measuring the economic well being of the bank could cause the required Operational Value-at-Risk to vary drastically. Especially, high pre-tax ROE, efficiency ratio and stock price are associated with a low shape parameter of the severity distribution, whereas a high market volatility, leverage ratio and unemployment rate are associated with higher tail risks. Finally, we discuss the fact that the considered approach could be an interesting tool to improve the estimation of the parameters in a Loss Distribution Approach and to offer an interesting methodology to study capital requirements variations throughout scenario analyses. [less ▲]

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See detailCharacteristics of Jupiter's auroral acceleration region
Ray, Licia; Gustin, Jacques ULg; Grodent, Denis ULg

Poster (2015, June)

Jupiter’s dynamic auroral region is the signature of magnetosphere-ionosphere coupling. The magnetospheric drivers of the emission are relatively well understood, yet the high-latitude characteristics of ... [more ▼]

Jupiter’s dynamic auroral region is the signature of magnetosphere-ionosphere coupling. The magnetospheric drivers of the emission are relatively well understood, yet the high-latitude characteristics of the interaction have not been measure in-situ. Ahead of Juno’s arrival next summer, we use HST STIS observations of Jupiter’s auroral emission to infer the location of Jupiter’s auroral acceleration region and the properties of the precipitating auroral electrons. We analyze two images of Jupiter’s northern emission, determining the precipitating electron energy and incident energy flux for the main aurora, Io spot, Ganymede footprint, and flare regions. The resulting relationships between energy flux and electron precipitation energy for the main auroral emission are compared to the theoretical relationship derived by Lundin & Sandahl [1978] for a range of auroral region locations, and temperatures and densities appropriate for the jovian system. [less ▲]

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See detailDevelopment of a field test to evaluate colostral immunity transfer in young calves
Guyot, Hugues ULg; Dubreucq, Pierre ULg; Lebreton, Pascal et al

Poster (2015, June)

Failure of transfer of immunity from dam’s colostrum generates a negative effect on calves’ health leading to increased morbidity and mortality (De Nise et al., 1989; Wittum and Perino, 1995). Unawareness ... [more ▼]

Failure of transfer of immunity from dam’s colostrum generates a negative effect on calves’ health leading to increased morbidity and mortality (De Nise et al., 1989; Wittum and Perino, 1995). Unawareness of the colostral quality and variation in the calf’s capability to efficiently absorb immunoglobulins (IgG) supports the need for specific evaluation of the immunity transfer at a herd level. The aim of the study was to evaluate the performances of a field test for passive immunity transfer (PIT) in calves. [less ▲]

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See detailControlled clinical trial of repeated left prefrontal transcranial direct current stimulation in patients with chronic minimally conscious state
Martial, Charlotte ULg; Thibaut, Aurore ULg; Wannez, Sarah ULg et al

Poster (2015, June)

A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (LDLPF) transiently improves consciousness in 43% of ... [more ▼]

A recent study showed that single-session anodal transcranial direct current stimulation (tDCS) applied to the left dorsolateral prefrontal cortex (LDLPF) transiently improves consciousness in 43% of patients in minimally conscious state (MCS) (Thibaut et al., 2014). We here test the potential effects and safety of repeated tDCS in severely brain-damaged patients with MCS. In this double-blind cross-over sham-controlled experimental design, we delivered two sessions of repeated (5 days of stimulation) tDCS, either anodal or sham in a randomized order. We stimulated the LDLPF cortex during twenty minutes in 20 MCS patients (12 men, aged 48±16 years, time since onset 78±95 months, 12 post-traumatic). Consciousness was assessed by the French adaptation of the Coma Recovery Scale Revised (CRS-R; Schnakers et al., 2008) before and after each stimulation. A treatment effect was observed for the comparison between CRS-R total scores at baseline and after 5 days of real tDCS (p<0.01). Behaviorally, 10/20 patients showed a tDCS-related improvement; 5 patients responded after the first stimulation and 5 other patients responded after 2, 3 or 4 days of stimulation. No side effect (e.g. epilepsy) was reported. Our results demonstrate that repeated (5 days) anodal LDLPF tDCS is safe and might improve signs of consciousness in about half of patients in MCS. It is important to note that the first session is not predictive for a future positive effect of the efficacy of the non-invasive electrical stimulation. [less ▲]

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See detailOptimisation de milieux de culture pour Bifidobacterium bifidum et Bifidobacterium crudilactis et étude de l’effet antimicrobien des surnageants de culture
Bondue, Pauline ULg; Delcenserie, Véronique ULg; Crevecoeur, Sébastien ULg et al

Poster (2015, June)

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est ... [more ▼]

Modulé entre autre par notre alimentation, le microbiote intestinal influence notre santé. Un enfant allaité sera en meilleure santé qu’un enfant nourri avec des formulations commerciales. Ceci est notamment dû à la présence d’oligosaccharides complexes dans le lait maternel (HMO). Les oligosaccharides ajoutés au lait maternisé sont d’origine végétale et leur structure est très éloignée de celle des HMO. Parce que les HMO ressemblent aux glycans de la paroi épithéliale, les pathogènes intestinaux infantiles s’y fixent et sont expulsés naturellement. Le lait de vache possède des oligosaccharides complexes (BMO), dont la structure est très similaire à celle des HMO. Les bifidobactéries rencontrées majoritairement dans les matières fécales d’un nourrisson devraient pouvoir métaboliser les BMO, tout comme celles isolées dans le lait de vache. Les objectifs de cette étude étaient d’étudier le potentiel de croissance de bifidobactéries d’origine bovine ou humaine sur des milieux de culture enrichis en lactosérum et BMO. Le deuxième objectif était de vérifier si le catabolisme de ces sucres complexes induisaient une synthèse de métabolites influençant l’expression de virulence de certains pathogènes tels qu’Escherichia coli O157 :H7. Une souche de Bifidobacterium bifidum, isolée à partir des matières fécales d’un nourrisson exclusivement allaité et une souche de Bifidobacterium crudilactis, isolée à partir de fromage au lait cru, ont été mises en culture dans des milieux contenant différentes sources d’hydrates de carbone (glucose, lactosérum naturellement riche en lactose et BMO, et 3’-syalillactose (3’SL)). Le 3’SL est un oligosaccharide complexe majoritaire parmi les BMO. Les surnageants des différents milieux de culture ont été prélevés et concentrés par lyophilisation puis mis en contact avec E. coli O157 :H7. L’expression relative de différents gènes de virulence d’E. coli O157:H7, fliC, ler, stx2b et luxS a été étudiée. Dans le futur, les BMO et certaines souches d’origine bovine ou humaine pourraient s’avérer être des compléments alimentaires intéressants pour maintenir ou rétablir la santé intestinale des jeunes enfants. [less ▲]

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See detailNonlinear Interpolation on Manifold of Reduced Order Models in Magnetodynamic Problems
Paquay, Yannick ULg; Bruls, Olivier ULg; Geuzaine, Christophe ULg

Poster (2015, June)

Proper Orthogonal Decomposition (POD) is an efficient model order reduction technique for linear problems in computational sciences, recently gaining popularity in electromagnetics. However, its ... [more ▼]

Proper Orthogonal Decomposition (POD) is an efficient model order reduction technique for linear problems in computational sciences, recently gaining popularity in electromagnetics. However, its efficiency has been shown to considerably degrade for nonlinear problems. In this paper, we propose a reduced order model for nonlinear magnetodynamic problems by combining POD with an interpolation on manifolds, which interpolates the reduced bases to efficiently construct the desired solution. [less ▲]

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See detailControlled synthesis of multi-functional polymers bearing pendant catechols for surface modifications
Patil, Nagaraj ULg; Aqil, Abdelhafid ULg; Jérôme, Christine ULg et al

Poster (2015, June)

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility ... [more ▼]

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility. However, limited by its poor adhesion towards surfaces, demands an addition modification strategies. Mussel adhesive proteins (MAPs) are potential models for adhesive polymers, which exhibits underwater adhesion towards dissimilar materials under environmentally challenging conditions. Most often experimentally simple, but structurally complex poly(dopamine) has been used as an analogues of MAPs for metal chelation, cross-linking and surface binding purposes. Inspired by MAPs, we have developed catechol-bearing copolymers for surface adhesion of stainless steel. This study describes the synthesis and reversible addition−fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA). A series of well-defined P(PEGAm-b-ADAn) and P(ADMAn-b-PEGMAm) copolymers across a range of molar masses (13−42 kg/mol) with low molar mass dispersities (Đ = 1.12−1.25) were reported for the first time. Post polymerization TFA treatment yields block copolymers bearing free –catechol units in quantitative yields (>95%). The self-assembling nature of amphiphilic block-copolymers was studied by 1H-NMR, DLS and TEM. Surface functionalization and anti-fouling experiments were performed in real time using quartz crystal microbalance coupled with dissipation (QCM-D). The copolymer upon oxidation yields reactive quinones, which can be exploited to cross-link with chitosan (also, polymers with free –NH2 and –SH groups), thereby producing nano(macro)gels. In general, these novel class of block copolymeric ligand systems can be foreseen as versatile ingredients in material chemistry to obtain biocompatible multifunctional systems, benefited by high water solubility with inherent stealth ability and protein-repellency, as well as effective chelating groups, and may find application for a variety of biomedical fields, of which we have illustrated an important example. [less ▲]

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See detailThe neuroimaging meta-analysis database: A data-sharing initiative for neuroimaging meta-analyses
Reid, Andrew; Bzdok, Danilo; Genon, Sarah ULg et al

Poster (2015, June)

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See detailEmpowering NGS technologies for the study and diagnostic of plant viruses - European COST Action FA1407
Massart, Sébastien ULg; Gentit, Pascal; Olmos, Antonio et al

Poster (2015, June)

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See detailExtracellular peptidase hunting for improvement of protein production in plant cells and roots
Lallemand, Jérôme ULg; Bouché, Frédéric ULg; Desiron, Carole et al

Poster (2015, June)

Plant-based biopharmaceuticals have gained a lot of interest in the past decade due to their reduced cost and relative safety compared to mammalian cell cultures. While the first plant-made recombinant ... [more ▼]

Plant-based biopharmaceuticals have gained a lot of interest in the past decade due to their reduced cost and relative safety compared to mammalian cell cultures. While the first plant-made recombinant proteins are now reaching the market, the production systems still need improvements to maximize their competitiveness, proteolysis being one of the main factors limiting the yields. Identifying and inhibiting in vivo endogenous proteases involved in the degradation of recombinant proteins could then lead to a significant increase in production yields. In this study, we focused on two different production systems in Arabidopsis thaliana: rhizosecretion and cell suspensions. Extracellular proteases of both systems were used in vitro to study the conditions of target protein degradation (Bovine Serum Albumine, BSA). First, proteases from both systems degrade BSA at both acidic and neutral-to-basic pH conditions. Then, serine and metallopeptidases were shown to be the main protease classes responsible for BSA degradation by rhizosecreted proteomes or extracellular cell culture media, respectively. Finally, the biochemical tests were coupled to a bioinformatics analysis of publicly available transcriptomic data, in order to reduce the number of the proteases most likely involved in BSA degradation. Using this method, only five serine proteases and two metallopeptidases remain candidates for an amiRNA-mediated in vivo inhibition. [less ▲]

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