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See detailE.coli prpoS::gfp strain as biosensor of glucose heterogeneity inside industrial bioreactors
Brognaux, Alison ULg; Delvigne, Frank ULg; Thonart, Philippe ULg

Poster (2010, December 08)

• OBJECTIVE: Escherichia coli is a microorganism widely used in the industry for the production of recombinant proteins. The performances obtained at the laboratory level are not reproducible at a large ... [more ▼]

• OBJECTIVE: Escherichia coli is a microorganism widely used in the industry for the production of recombinant proteins. The performances obtained at the laboratory level are not reproducible at a large scale. Actually, the mixing operation is not efficient enough: gradients of glucose and oxygen appear when operating in fed-batch mode (addition of glucose during the culture). These gradients cause adverse impacts on the production of biomass and recombinant protein. The aim of this work is to use the microbial population as biocaptor of the encoutered stress inside heterogeneous industrial bioreactors to better scale-up and regulate these reactors. • MATERIALS AND METHODS: A plasmid carrying a stress promoter followed by the coding sequence of the Green Fluorescent Protein (GFP) is introduced in the bacterial host (in our case, the strain E. coli K12 will be considered as a model organism). When the cell is submitted to given stress condition, GFP synthesis is induced and accumulated into the cytoplasm, leading to the increase of the cell's fluorescence. Flow cytometry detection is used in order to quantify the fluorescence at the single cell level. Obtained results are frequency histograms of fluorescenceintensity in the microbial population • RESULTS: The rpoS gene is a gene of the general stress response, mainly induced at the entrance to stationary phase (during a lack of glucose). The tracking of the GFP fluorescence linked to the activation / repression of the rpoS promoter gives good results. Indeed, there is appearance of a segregation at the level of the GFP content among the microbial population. The intensity of the segregation, as well as its time of appearance during the culture can be related to the bioreactor mixing efficiency. • CONCLUSION: prpoS::gfp strains can be used as biosensors of the heterogeneity of glucose encountered inside industrial reactors. • POTENTIAL APPLICATIONS & KEY BENEFITS: These strains could be used to validate a fed-batch regulation (addition of glucose) at the industrial level. [less ▲]

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See detailAzoxystrobin and epoximazole sensitivity profiles of Mycosphaerella graminicola populations from the Grand-Duchy of Luxemburg in 2007 and 2008
Vrancken, Carine; Dubos, Tiphaine; El Jarroudi, Moussa ULg et al

Poster (2010, December 07)

Mycosphaerella graminicola strains were isolated from symptomatic winter wheat (Triticum aestivum) and spelt (Triticum spelta) leaves sampled across the Grand-Duchy of Luxembourg. In total, 484 strains ... [more ▼]

Mycosphaerella graminicola strains were isolated from symptomatic winter wheat (Triticum aestivum) and spelt (Triticum spelta) leaves sampled across the Grand-Duchy of Luxembourg. In total, 484 strains were isolated from winter wheat, and 31 from spelt leaves. The sensitivity profiles of these strains towards azoxystrobin (Amistar®, Syngenta Agro GmbH, Germany) and against epoxiconazole (Opus®, BASF Belgium NV/S A, Brussels, Belgium) were assessed in microplates, allowing to test 10 different concentrations for each active substance (0, 0.00316, 0.01, 0.0316, 0.1, 0.316, 1, 3.16, 10 and 31.6μg/mL). 100μ g/mL of salicylhydroxamic acid (SHAM) was also added to the medium, in order to prevent the strains from using alternative respiration. Results of the sensitivity tests for azoxystrobin showed a dose-dependent decrease of in vitro growth for all the strains. During both years, strains could be divided into two distinct sub-populations in relation to their azoxystrobin sensitivity, thus forming a bimodal distribution commonly reported to be associated with a single gene-mediated resistance. For wheat, the dominant sub-population was the one showing full resistance to azoxystrobin. The results of the sensitivity tests to epoxiconazole in liquid media showed a dose-dependent decrease of fungal growth for all the strains tested. The EC50 values followed an unimodal distribution. When the sensitivity distribution of the strains collected in 2008 (n=379) was compared to that observed in 2007, although the populations have remained unimodal, a minor shift towards less sensitive populations was observed. Compared to strains originating from wheat, the spelt strains were more sensitive towards both fungicides (p ≤ 0.001). [less ▲]

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See detailEvaluating analytical results reliability using a Bayesian probability criterion
Rozet, Eric ULg; Lebrun, Pierre ULg; Boulanger, Bruno ULg et al

Poster (2010, December 02)

In pharmaceutical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the release of ... [more ▼]

In pharmaceutical industries, quantitative analytical methods such as HPLC play a key role. Indeed, the analytical results obtained from them are used to make crucial decisions such as the release of batches of drugs, the evaluation of safety and efficacy of new drug candidates or the monitoring of patients health. Prior to their routine use, analytical methods are submitted to a stringent validation study where they have to demonstrate that they are fit for their final purpose, i.e. providing accurate result . Typically this demonstration is made by either providing point estimates of systematic error (bias) and random error (variance) or sometimes by providing interval estimates of these statistical parameters at several well defined concentration levels of the target analyte. They are then compared to maximum acceptable levels. More recently, tolerance intervals approaches have been proposed that are evaluated in a similar way at these key concentration levels. However none of these decision approaches allow knowing the probability to obtain accurate results over the whole concentration range of interest. Frequentist approximations have been proposed to estimate this probability but only at the concentration levels experimentally tested and not for the whole range of interest. In this work, a linear hierarchical Bayesian approach is proposed. It takes into account the potential random characteristic of the slope and intercept observed from one analytical run to the other, and also integrates the possible covariance between the parameters. Additionally, heteroscedasticity of the residual variance over the concentration range investigated is taken into account. A situation regularly observed in practice. Finally a reliability profile for the whole concentration range studied is obtained using MCMC sampling. This profile provides the probability (Prel) to obtain accurate results over the full concentration range investigated. This profile is then compared to a minimum reliability probability (Pmin) that will define the valid concentration range of the analytical method. The usefulness of this approach is illustrated through the validation of a bioanalytical method and also compared with a one concentration level at a time frequentist approach derived from tolerance intervals. [less ▲]

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See detailOrgano-mineral imprints in fossil cyanobacterial mats of an Antarctic lake
Javaux, Emmanuelle ULg; Lepot, Kevin ULg; Deremiens, Leo et al

Poster (2010, December)

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See detailA GPS/GNSS dense network used to monitor ionospheric positioning error
Wautelet, Gilles ULg; Lejeune, Sandrine; Warnant, René ULg

Poster (2010, December)

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See detailConservation of endemic plants from the Katanga copper belt (DR Congo)
Lebrun, Julie ULg; Minengo Handjila, Guylain; Weiskopf, Thomas et al

Poster (2010, December)

The Katanga copper belt, where natural outcrops of copper-rich rocks are colonised by highly original plant communities, has been recognised as a hotspot for metallophyte species. The flora comprises more ... [more ▼]

The Katanga copper belt, where natural outcrops of copper-rich rocks are colonised by highly original plant communities, has been recognised as a hotspot for metallophyte species. The flora comprises more than 600 species from which 30 are endemics. These plants represent a valuable phytogenetic resource for revegetation and restoration programs, for the phytostabilisation and for the remediation of heavy metal pollutions. However, the flora of metalliferous soils is threatened by mining activities in Katanga. Actions aiming at preserving these species are therefore urgent. Since 2007, a unique conservation project has been launched by scientists supported by a mining company. The aim is to elaborate a program that allows biodiversity conservation while being compatible with mining activities. The project combines in-situ and ex-situ conservation strategies involving ecosystem reconstruction, species translocations, protected areas designation and the development of seed banks in Belgium and in Katanga. [less ▲]

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See detailVaccine against human papillomavirus (HPV)-associated lesions induces collaboration between natural killer and dendritic cells in vitro.
Langers, Inge ULg; Reschner, Anca ULg; Renoux, Virginie ULg et al

Poster (2010, December)

Cervical cancer, the second most frequent gynaecological malignancy in the world, is caused by infection with high-risk human papillomaviruses (HPV). HPV16 and/or 18 are detected in more than 70% of these ... [more ▼]

Cervical cancer, the second most frequent gynaecological malignancy in the world, is caused by infection with high-risk human papillomaviruses (HPV). HPV16 and/or 18 are detected in more than 70% of these tumours. Prophylactic HPV-L1 virus like particle (VLP) vaccines are highly efficient to protect against HPV16 and HPV18 infection, but not against established infection. In this context, we study the effect of HPV-VLP on natural killer cells (NK) and on the crosstalk between NK and Dendritic Cells (DC). In order to know if HPV-VLP are able to enter in NK cells, we used fluorescent HPV-VLP with flow cytometry and confocal microscopy. HPV-VLP were internalised more rapidly in NK cells than in DC. They were already detected inside NK cells after 10 min of contact at 37°C. We also observed in CD107 assays, that HPV-VLP induce degranulation of NK cytotoxic granules. Previous works have shown that HPV-VLP were able to activate DC. We confirmed these results and observed an increase of CD69 cell surface expression and IFN-γ production by NK cells in the presence of DC activated by VLP. Interestingly, NK cells seemed to further activate DC in the presence of VLP as shown by an up-regulation of HLA-DR and CD86 on DC. Moreover, NK cells in the presence of HPV-VLP induced the production of IL12p70, but not the immunosuppressive cytokine IL10. Our results suggest that NK cells could play a role in the activation of DC induced by HPV-VLP during the vaccination against cervical cancer. Supported by the Belgian FNRS-Télévie [less ▲]

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See detailNANOTRIBOLOGICAL AND NANOMECHANICAL CHARACTERIZATIONS OF MEMS MATERIALS
Pustan, Marius ULg; Rochus, Veronique; Golinval, Jean-Claude ULg

Poster (2010, December)

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See detailResearch activities in 3D sound and Auralization (in Intelsig)
Embrechts, Jean-Jacques ULg

Poster (2010, December)

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See detailDiscovery of pulsed polar flares in the Jovian aurorae
Bonfond, Bertrand ULg; Vogt, M~F; Grodent, Denis ULg et al

Poster (2010, December)

The most active part of the aurora at Jupiter is certainly the polar region, i.e. the emissions located poleward of the main auroral oval. This region is known to occasionally show localized but dramatic ... [more ▼]

The most active part of the aurora at Jupiter is certainly the polar region, i.e. the emissions located poleward of the main auroral oval. This region is known to occasionally show localized but dramatic enhancements of its brightness, referred to as polar flares. These emissions have been associated with the polar cusp, based on their location in the polar cap. In summer 2009, right after the refurbishment of the Space Telescope Imaging Spectrograph camera, the Hubble Space Telescope acquired the longest high-time resolution sequence ever of images of the Jovian aurora. We report the first observations of a quasi-periodicity in the occurrence of these flares, with a timescale of ~2-3 minutes. By using a magnetic flux mapping model, we show that these features originate from a region located at a radial distance ranging from 80 to 100 Jovian radii and local times between 10:00 and 15:00. As a consequence, by analogy with similar behaviors observed in the Earth aurora, we suggest that these emissions could be attributed to pulsed reconnections in the dayside magnetopause. [less ▲]

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See detailOPTIMIZACIÓN DE BIOMATERIALES PARA MODIFICACIÓN DE LA SUPERFICIE CELULAR
Cerda-Cristerna, B.I.; Flores, H; Pozos, A et al

Poster (2010, December)

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See detailRank-constrained linear regression: a Riemannian approach
Meyer, Gilles ULg; Bonnabel, Silvère; Sepulchre, Rodolphe ULg

Poster (2010, December)

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See detailAlternative photosynthetic electron pathways in different clades of Symbiodinium: the Mehler reaction
Roberty, Stéphane ULg; Poulicek, Mathieu ULg; Franck, Fabrice ULg

Poster (2010, December)

The high productivity of coral reef ecosystems is largely attributed to the mutualistic symbiosis between reef-building corals and their intracellular dinoflagellate in the genus Symbiodinium commonly ... [more ▼]

The high productivity of coral reef ecosystems is largely attributed to the mutualistic symbiosis between reef-building corals and their intracellular dinoflagellate in the genus Symbiodinium commonly referred to as zooxanthellae. These photosynthetic algae translocate a majority of their photosynthetically fixed carbon to the host and contribute greatly to their metabolic needs (Muscatine, 1990) and the calcification process (Gattuso, 1999). In the natural environment the holobiont have to cope with significant daily variations in light intensities that sometimes exceed Symbiodinium photosynthetic capacity. Fortunately, photosynthetic organisms possess regulatory features that help to ensure that high light intensities can be endured without the accumulation of photodamage. Thus, the regulation of photosynthesis can be viewed as a dynamic balance between photosynthetic efficiency (photochemical quenching) and photoprotection processes (i.e. non-photochemical quenching). Among them, the role of O2 as an alternative electron acceptor within the chloroplast could play a critical role (Ort & Baker, 2002). Under particular environmental conditions when sinks for photosynthetic electrons are scarce, the direct reduction of oxygen by the PSI could sustain significant levels of photosynthetic electron flux by initiating the ΔpH formation and of NPQ, regulating the ratio of ATP/NADPH to match the requirements of carbon reduction. However, this process leads to the formation of reactive oxygen species that are rapidly detoxified by superoxide dismutase and ascorbate peroxidase. An additional electron flux associated with this oxygen pathway is directed to the reduction of monodehydroascorbate (MDA), which is generated as a result of peroxide reduction by ascorbate (Asada, 2000). The present study aimed to highlight the existence of alternative photosynthetic electron pathways and more especially the Mehler ascorbate peroxidase pathway in different clades of Symbiodinium, cultivated at low and high light intensities. -Muscatine L (1990) The role of symbiotic algae in carbon and energy flux in reef corals. In: Dubinsky Z(ed) Ecosystems of the world: coral reefs. Elsevier, Amsterdam, pp 1-9. -Gattuso JP, Allemand D and M Frankignoulle (1999) Photosynthesis and calcification at cellular, organismal and community levels in coral reefs: A review on interactions and control by carbonate chemistry. American Zoologist 39(1): 160-183. -Ort, D. R. and N. R. Baker (2002). A photoprotective role for O2 as an alternative electron sink in photosynthesis? Current Opinion in Plant Biology 5(3): 193-198. -Asada, K. (2000) The water-water cycle as alternative photon and electron sinks. Philosophical Transactions of the Royal Society B-Biological Sciences 355(1402): 1419–1431. [less ▲]

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See detailPattern of early eukaryote evolution in Precambrian oceans
Javaux, Emmanuelle ULg

Poster (2010, December)

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See detailRelating Jupiter's auroral features to magnetospheric sources
Vogt, Marissa F.; Kivelson, Margaret G.; Khurana, Krishan K. et al

Poster (2010, December)

In order to understand the physical processes that produce the various auroral features we must first understand how the auroral emissions are linked to magnetospheric sources. However, magnetic mapping ... [more ▼]

In order to understand the physical processes that produce the various auroral features we must first understand how the auroral emissions are linked to magnetospheric sources. However, magnetic mapping of Jupiter’s polar auroral emissions to equatorial regions in which source currents are plausibly generated is highly uncertain because the available field models are inaccurate beyond ~30 Jovian radii. We have related auroral features to their magnetospheric sources through a flux equivalence calculation, where we require that the magnetic flux in some specified region at the equator equals the magnetic flux in the area to which it links in the ionosphere. This approach is preferred to tracing model field lines for mapping the auroral polar regions, because the latter method is inaccurate at large distances. Here we present our results, highlighting new mappings for the southern hemisphere, and will compare our mapping to auroral observations from both hemispheres. In particular we relate equatorial regions in which reconnection events have been identified with the locations of polar dawn spots and other possible auroral signatures of tail reconnection. We find that the mapping reproduces several other key auroral features. The polar auroral active region maps to just outside the dayside magnetopause, a region that we identify as the Jovian polar cusp. The polar auroral swirl region maps to open tail field lines and is interpreted as the Jovian polar cap. These interpretations are consistent with some earlier predictions based on auroral observations. We identify the boundary between open and closed flux in the ionosphere, which previously was not well defined. We show that the magnetic flux through the regions interpreted as the polar caps in both hemispheres closely matches the estimated flux through the tail lobe, consistent with the suggestion that this area maps to open field lines. [less ▲]

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See detailUsing 3D to understand human motion
Schwartz, Cédric ULg; Forthomme, Bénédicte ULg; Bruls, Olivier ULg et al

Poster (2010, December)

The understanding and tracking of human motion has been a subject of interest in the scientific community for more than one century. The long history of human motion analysis comes from the large scope of ... [more ▼]

The understanding and tracking of human motion has been a subject of interest in the scientific community for more than one century. The long history of human motion analysis comes from the large scope of applications of such measurement that can be found in medicine, biomechanics, sport, ergonomics, and even civil engineering. More recently, those technologies have also been widely exploited for the development of animation movies and games. Needless to say, the techniques used one century ago significantly differ from those used today. This paper describes in a first part the evolution of the technological capabilities for motion analysis and the actual limitations. From this analysis and in a second part, we describe the experience related to the creation of a motion analysis laboratory at the University of Liège and show how such a platform could be the center of a multidisciplinary research and provide valuable information to various communities. [less ▲]

Detailed reference viewed: 313 (70 ULg)
See detailRoutes for the preparation of advanced polymer/carbon nanoparticles based materials
Vuluga, Daniela ULg; Thomassin, Jean-Michel ULg; Huynen, Isabelle et al

Poster (2010, November 29)

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See detailChitosan nanofiber membranes for tissue engineering - synthesis, characterization and properties
Toncheva, Natalia ULg; Aqil, Abdelhafid ULg; Croisier, Florence ULg et al

Poster (2010, November 29)

This poster was presented by Natalia Toncheva

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See detailNew fluorinated surfactants for nanogels preparation in supercritical CO2
Alaimo, David ULg; Beigbeder, Alexandre; Dubois, Philippe et al

Poster (2010, November 29)

Detailed reference viewed: 42 (7 ULg)
See detailElectrografting and LbL deposition for the elaboration of antimicrobial coatings
Aqil, Abdelhafid ULg; Cécius, Michaël; Jérôme, Christine ULg

Poster (2010, November 29)

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See detailPMMA/carbon nanotube nanocomposites foams for EMI shielding application
Thomassin, Jean-Michel ULg; Molenberg, Isabel; Huynen, Isabelle et al

Poster (2010, November 29)

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See detailTight Glycemic Control Models for Critically Ill Patients in Intensive Care Units
Penning, Sophie ULg; Le Compte, Aaron; Desaive, Thomas ULg et al

Poster (2010, November 26)

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See detailComputational modelling of calcium mediated bone regeneration
Carlier, Aurélie ULg; Chai, Yoke Chin; Theys, Tina et al

Poster (2010, November 26)

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See detailInfluence of thermoelectric coupling on ectopic beats generated by mechano-electric feedback (MEF) in a one-dimensional cardiac fiber model
Collet, Arnaud ULg; Desaive, Thomas ULg; Pierard, Luc ULg et al

Poster (2010, November 26)

The influence of thermal processes on electrophysiology has clearly been underlined by Bini et al., using a FitzHugh--Nagumo-type (FHN-type) model. When the temperature is raised, the action potential ... [more ▼]

The influence of thermal processes on electrophysiology has clearly been underlined by Bini et al., using a FitzHugh--Nagumo-type (FHN-type) model. When the temperature is raised, the action potential duration (APD) has been shown to shorten, while the action potential (AP) amplitude decreases, and the conduction velocity increases. In this research, we investigate the effects of thermoelectric coupling on mechano-electric feedback (MEF), and more specifically, on ectopic beats generated by MEF. To investigate these effects, thermoelectric coupling is introduced in a one-dimensional electromechanical model of a cardiac fiber, which considers excitation-contraction coupling (ECC), as well as MEF. [less ▲]

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See detailModeling the instantaneous pressure-volume relationship in the left ventricle
Lucas, Alexandra ULg; Dauby, Pierre ULg; Kolh, Philippe ULg et al

Poster (2010, November 26)

Pressure-volume loops are a common modeling tool of the cardiovascular system. They are very useful because they characterize the global function of the cardiac pump and can also be analyzed ... [more ▼]

Pressure-volume loops are a common modeling tool of the cardiovascular system. They are very useful because they characterize the global function of the cardiac pump and can also be analyzed by considering the various phases of the cardiac cycle and marking each point of a cycle with the corresponding time. When several loops are considered, the points corresponding to the same time t in each loop can be joined to define a curve named isochrone. In this work, we are interested in models of the instantaneous pressure-volume relationship, i.e. isochrone models. More precisely, we concentrate on the 6 models considered by Lankhaar et al. [1] and we propose a critical analysis of the work of these authors and suggest some improvement of their procedure. [1] Lankhaar J.W. et al. Annals of Biomedical Engineering, Volume 37, Number 9, 1710-1726, 2009. [less ▲]

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See detailA Boolean network model of the growth plate
Kerkhofs, Johan ULg; Roberts, Scott J; Luyten, Frank P et al

Poster (2010, November 26)

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See detailMultiple Material Mesh Generation For Biomedical Applications
D'Otreppe, Vinciane ULg; Boman, Romain ULg; Ponthot, Jean-Philippe ULg

Poster (2010, November 26)

The finite element (FE) method is commonly used in biomedical applications for the simulation of the behaviour of biological structures. A key component in FE simulation is the creation of a finite ... [more ▼]

The finite element (FE) method is commonly used in biomedical applications for the simulation of the behaviour of biological structures. A key component in FE simulation is the creation of a finite element mesh. In medical applications, the meshes should be directly generated from the medical scans. Moreover, biological structures are usually composed of several inner regions that need to be separately segmented, labelled and meshed to be able to apply different material properties in the finite element model. A procedure to create surface meshes from a multi-valued volume data sets is proposed. Following properties are guaranteed: (1) The generated mesh consists of a set of non manifold triangle meshes that separate each connected component in the labelled data set. These interface meshes join each other consistently along their boundaries, i.e., no T junctions nor gaps may appear. (2) The surface mesh is a geometrically accurate representation of the data represented in the medical scans. However, it is not be tainted by the typical aliasing and staircase artifacts that are due to the discrete nature of the voxels. [less ▲]

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See detailMinimal cardiovascular system model including physiological mitral valve opening
Paeme, Sabine ULg; Moorhead, Katherine ULg; Chase, J. Geoffrey et al

Poster (2010, November 26)

This research describes a new closed-loop cardiovascular system (CVS) model including a model of the left atrium and a model describing the progressive aperture of the mitral valve

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See detailTendon lesion and platelet-rich plasma (PRP) injection
Kaux, Jean-François ULg; Drion, Pierre ULg; Renouf, Julien et al

Poster (2010, November 25)

Introduction: For a few years, the positive effects of platelets on the healing process of different tissues (skin, bones...) were demonstrated. In fact platelets contain lots of growth factors which can ... [more ▼]

Introduction: For a few years, the positive effects of platelets on the healing process of different tissues (skin, bones...) were demonstrated. In fact platelets contain lots of growth factors which can be release locally and enhance the healing process. Thus the aim of our experiment was to ascertain by an original mechanical measure whether the use of PRP was of interest for accelerating the healing process of rats’ Achilles tendons after surgical induced lesion. Methods: A 5mm defect was surgically induced in 90 rats’ Achilles tendon. Rats were divided into 2 groups of 45: (A) control (no treatment) and (B) PRP treatment. Rats of group B received a PRP injection in situ after the surgery. Afterwards, rats of both groups were placed in their cages without immobilization. After 5, 15 and 30 days, 10 traumatized Achilles tendons of each group were dissected and removed. Immediately after sampling, tendons were submitted to a biomechanical tensile test up to rupture, using a “Cryo-jaw”. After that, transcriptomic analyses were made on the tendon samples, to study the expression of type III collagen, matrix metalloproteases and tenomodulin. A hydroxyproline dosage was finally realised to quantify the collagen in the tendon during its healing process. Tendons of the 15 remaining rats of each group were subjected to a histological study, respectively at day 5, 15 and 30 (5 rats for each time). Results: We demonstrated that (1) the stress (F) during biomechanical tensile test up to tendon rupture was significantly greater for tendons which had been submitted to an injection of PRP compared to the control group; (2) the surface (S) area of the section of the tendon was greater in the PRP group during the 15 first days, but this section was similar after 30 days in the 2 groups; (3) the ration F/weight of the rat was significantly greater in the PRP group at each time; (4) constrain was similar after the 15 first days but was significantly greater in the PRP group after 30 days. Histological study showed that PRP could enhance cells proliferation, angiogenesis and collagen organisation. Our biochemical analyses did not explain beneficial effects of PRP. Indeed, there was no significant difference between the expressions of different studied genes. Conclusion: Our animal study demonstrated that an injection of PRP could accelerate the tendons healing process and improve its quality. [less ▲]

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See detailTendon lesion and VEGF-111 injection
Kaux, Jean-François ULg; Drion, Pierre ULg; Libertiaux, Vincent ULg et al

Poster (2010, November 25)

Introduction: Tendon lesion is one of the most frequent pathology in sports and by physical workers. This pathology often becomes chronic. For this reason, it is of interest to develop new treatments ... [more ▼]

Introduction: Tendon lesion is one of the most frequent pathology in sports and by physical workers. This pathology often becomes chronic. For this reason, it is of interest to develop new treatments. Injection of platelet-rich plasma (PRP) seems to be a promising one by releasing growth factors (GF) locally. Among all the GF released by activated platelets, the vascular endothelial growth factor-A (VEGF-A) is known to induce positive effects on vascular function and angiogenesis, and could be implicated in the healing process of tendons. Recently, a novel VEGF-A isoform was identified, the VEGF-111, a biologically active and proteolysis-resistant VEGF-A isoform, also known to present beneficial effects on ischemic diseases. This prompted us to evaluate whether VEGF-111 would have a therapeutic interest within the framework of the tendon pathology. Methods: 60 Rats were divided into 2 groups: A: control (no injection), B: VEGF-111 treatment. A 5mm defect was surgically induced in rat Achilles tendon after resection of plantaris tendon. Rats received a local injection of VEGF-111 (100ng) in situ after the surgery and were placed in their cages without immobilization. After 5, 15 and 30 days, the traumatized Achilles tendons of 10 rats of both groups were removed and dissected during their healing process. Immediately after sampling, tendons were submitted to a biomechanical tensile test up to rupture, using a “Cryo-jaw”. Rats were then euthanized. Statistical analyses were made with an ANOVA. Values are significant when p-value is below 0.05. Results: Our results showed that the developed force necessary to induce tendon rupture during biomechanical tensile test was greater for tendons which had received an injection of 100ng of VEGF-111. These results were already noticed from day 5 onwards. The ratio between force and weight increased with time in both groups, but this ratio was greater for tendons which had been submitted to an injection of VEGF111. The surface area of the section of the tendons increased between 5 and 15 days followed by a stabilization. After 30 days, sections in both groups were similar. Thus, the constraint was similar after 5 and 15 days but was better for VEGF111 group after one month. Discussion - Conclusion: This experimentation has shown that a 100ng injection of VEGF-111 stimulated tendon healing process as suggested by the increased force needed to break tendons during its healing process and the increased of constraint in comparison with the control group. Other experimentations with different concentration of VEGF111 are now in process. Acknowledgement : This experimentation was partially financed by “Standard de Liège 2007” and “Lejeune-Lechien 2008” grants. [less ▲]

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See detailIntrinsic modification of tendon structure after concentric or excentric training
Kaux, Jean-François ULg; Drion, Pierre ULg; Besançon, Benoît et al

Poster (2010, November 25)

Introduction: It is well known that eccentric training is a successful way of treating chronic tendinopathy. Although clinical results are very positive, beneficial morphological and histological effects ... [more ▼]

Introduction: It is well known that eccentric training is a successful way of treating chronic tendinopathy. Although clinical results are very positive, beneficial morphological and histological effects have not yet been elucidated. The aim of our experiment was to determine if there exist any intrinsic modifications in a tendon trained in concentric or eccentric modes, in a rat model, using an original method of measurement (cryo-jaws). Methods: 18 rats were divided into 3 groups: 6 for the control group, without physical restraint; 12 for a training of1 hour, 3 times a week, for 5 weeks, at a speed of 17m/min (1km/h), on a inclined treadmill: 6 rats running uphill at +15° for the concentric effort (group C) and 6 rats running downhill at -15° for the eccentric effort (group E). After this training period, the Achilles, patellar and tricipital tendons of both limbs were surgically removed in all 18 rats. Tendons taken from five rats of each group were subjected to a tensile test up to rupture using a “cryo” jaw. Tendons of the remaining rat of each group were subjected to a histological study. Results: The results showed significant changes in group E only: (1) an increase of the force required to rupture the patellar and tricipital tendons; (2) an improvement of the ratio between the force necessary to rupture the tricipital tendon and the body mass of the rats; (3) an increase of the surface area of the section of the tricipital tendon. No significant change was observed as far as constraint was concerned between groups. Histologically, we saw, in the group E, more peripheral blood vessels and a greater proportion of collagen. Conclusion: This study showed that the mechanical properties of tendon tissue are enhanced by eccentric training. Tendons become stronger, the amount of collagen increases and there is probably more interaction between collagen fibers (mechanotransduction). [less ▲]

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See detailValorisation de la Carte des Sols dans un cadre inattendu - Le tourisme à caractère scientifique
Rekk, Samantha; Legrain, Xavier ULg; Bock, Laurent ULg et al

Poster (2010, November 24)

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See detailEvaluation des risques de compaction des sols en Région wallonne
Rosiere, Charlotte ULg; Verbrugge, Jean-Claude; Destain, Marie-France ULg

Poster (2010, November 24)

Le projet de directive européenne COM(2006)232 établit un cadre général pour la protection des sols. Le projet prévoit que les états membres identifient les zones susceptibles d’être touchées par des ... [more ▼]

Le projet de directive européenne COM(2006)232 établit un cadre général pour la protection des sols. Le projet prévoit que les états membres identifient les zones susceptibles d’être touchées par des processus de dégradation (érosion, compaction, salinisation, …) et qu’ils proposent des mesures afin de réduire les risques. La compaction peut affecter la macroporosité, les mouvements de l’eau et de l’air dans le sol, les mécanismes de croissance racinaire, le développement de la faune du sol. De ce fait, elle est donc souvent à l’origine d’une diminution du rendement des cultures. En Région wallonne, les machines destinées à la récolte de betteraves risquent d’engendrer une compaction du sol car elles sont souvent utilisées alors que le sol est humide et que les charges à l’essieu sont importantes. Les machines d’exploitation forestière présentent également des risques pour la compaction du sol. La contrainte de préconsolidation (Pc) est considérée comme la valeur à ne pas dépasser pour éviter que le sol subisse des dégâts difficilement réversibles. Si les contraintes appliquées sont supérieures à Pc, le sol garde un comportement élastique (état réversible) et il n’y a pas de modification dans l’organisation de la porosité du sol. Par contre, si les contraintes appliquées sont supérieures à Pc, le sol entre en plasticité et ses fonctions naturelles sont perturbées. Dans un premier temps, des cartes de sensibilité du sol à la compaction sont élaborées. Elles évaluent la contrainte de préconsolidation des sols de la Région wallonne, au moyen des fonctions de pédotransfert (FPT) de Lebert et Fleige (2003). L’impact des engins sur le sol est étudié au niveau du ‘subsoil’, sous la couche de labour, là où le sol ne peut pas être régénéré par des outils classiques de travail du sol. Les paramètres des FPT sont accessibles au sein de Aardewerk ou sont trouvés dans la littérature. Les valeurs de Pc sont classées selon 6 niveaux de sensibilité, à deux états hydriques différents. Dans un deuxième temps, la distribution des contraintes verticales générées par le passage d’engins ‘types’, caractérisés par les dimensions des pneus, la charge à l’essieu et la pression de gonflage, est calculée à l’aide du logiciel Soilflex. Les Pc du sol sont alors comparées aux contraintes verticales induites par les engins, pour aboutir à des cartes de risque de compaction. Celles-ci simulent 4 scénarios : deux teneurs en eau et deux types d’engins. Afin de valider ces deux types de cartes, des tests oedométriques destinés à mesurer Pc sont réalisés sur des sols agricoles et forestiers. Pour faciliter la démarche et calculer les FPT de Lebert et Fleige avec une plus faible incertitude, il serait utile que la CNSW comporte des données relatives aux fractions granulométriques, à la matière organique des sols, la cohésion, l’angle de frottement interne, la masse volumique apparente sèche de sol, … [less ▲]

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See detailInfluence du type de sol et de son occupation sur la distribution des éléments traces métalliques entre les différents compartiments du sol : Stratégie et démarche d’échantillonnage
Lienard, Amandine ULg; Colinet, Gilles ULg

Poster (2010, November 24)

En Région wallonne, les sols contaminés en éléments traces métalliques (ETM) par retombées atmosphériques parsèment les anciennes régions industrielles du bassin sambro-mosan. C’est le cas du paysage ... [more ▼]

En Région wallonne, les sols contaminés en éléments traces métalliques (ETM) par retombées atmosphériques parsèment les anciennes régions industrielles du bassin sambro-mosan. C’est le cas du paysage entourant la réserve de Sclaigneaux (commune d’Andenne) connue pour ses pelouses calaminaires. Celles-ci trouvent leur origine dans les retombées de poussières contaminées provenant des cheminées d’évacuation d’une usine de zinc et plomb durant plus d’un siècle (1856 à 1978). Les cheminées, situées au sommet de la falaise sur la rive gauche de la Meuse, ont été détruites en 1982. Par cette étude, nous souhaitons observer la distribution des ETM dans les différents compartiments du sol et l’influence sur celle-ci du type de sol et de l’occupation du sol. La zone d’étude choisie est une maille circulaire de 3km de rayon centrée sur la zone des cheminées d’évacuation. Ce choix de maille permettra d’étudier l’offre en ETM du sol sur une distance constante dans toutes les directions. Elle est située dans le bassin hydrographique de la Meuse entre la Hesbaye, au nord, et le Condroz, au sud. Un plan d’échantillonnage stratifié par ordre d’importance des facteurs a été mis en place. Tout d’abord, une première sélection de sols a été opérée parmi les principaux types de sols répartis sur la zone sur base de l’ensemble de leur couverture cartographique. Les sols non cartographiés ou artificiels ainsi que les regroupements de complexes de sols pour lesquels les informations en notre possession sont insuffisantes ont ainsi été abandonnés. Une deuxième sélection porte sur les occupations de sols suivantes, cultures - prairies – forêts ; seuls six sols types de sols sont présents sous les trois occupations. Enfin, le choix final se porte sur les sols présents dans les quatre directions suivantes nord, est, ouest et sud. Au final, seulement trois unités de sols satisfont les exigences décrites ci-dessus. Les lieux d’échantillonnage sont répartis pour chaque combinaison sol-occupation sur les quatre directions. En tout, plus de 250 sondages seront réalisés sur cette zone d’environ 2.800ha pour optimiser la représentativité de l’échantillonnage. [less ▲]

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See detailMéthodologie d’acquisition d’une collection d’échantillons de sols liés aux matériaux parentaux en Wallonie
Legrain, Xavier ULg; Renneson, Malorie ULg; Genot, Valérie ULg et al

Poster (2010, November 24)

Malgré l'exiguïté de son territoire, la Wallonie est dotée d’un contexte géologique particulièrement varié et contrasté. Des grandes géostructures aux formations lithostratigraphiques, cette diversité se ... [more ▼]

Malgré l'exiguïté de son territoire, la Wallonie est dotée d’un contexte géologique particulièrement varié et contrasté. Des grandes géostructures aux formations lithostratigraphiques, cette diversité se reflète au niveau des situations pédologiques rencontrées. En effet, l’altération des roches, à l’origine du matériau parental, constitue un des processus majeurs indispensables à la formation d’un sol. Par ailleurs, à travers sa nature et sa composition, ce matériau d’origine est reconnu comme un des facteurs prépondérants influençant la pédogenèse, et de ce fait, les propriétés des sols. Fort de ce constat, l’Unité de Science du Sol de Gembloux Agro-Bio Tech, à travers la collaboration de divers projets, a entrepris la collecte d’échantillons de sols, en relation avec les matériaux parentaux à l’origine de la majorité des sols présents en Wallonie. L’objectif poursuivi est (i) d’acquérir des données à caractère « permanent », intrinsèques à ces matériaux parentaux, afin d’en dégager une signature chimique, physico-chimique, physique et spectrale, et (ii) de mettre en évidence l’influence tant du matériau parental que de l’occupation du sol sur les propriétés des horizons de surface. L’originalité du travail réside en partie dans la stratégie d’échantillonnage, basée sur une stratification pédologique et géographique, par la prise en compte respectivement de la Carte des Principaux Types de Sols de Wallonie et des Unités de l’Espace Rural. Les choix opérés ont conduit à la sélection de 12 matériaux parentaux, chacun faisant l’objet de prélèvements en 10 points (surface et profondeur). La localisation précise de ces points a été déterminée sur base d’une analyse et de la confrontation de documents cartographiques existants, se rapportant essentiellement aux sigles pédologiques, aux formations lithostratigraphiques, au relief et à l’occupation des sols. Un total de 258 échantillons a ainsi été prélevé en 120 points (76 en culture, 15 en prairie temporaire et 29 en prairie permanente). Parmi les analyses déjà réalisées citons, outre le menu d’analyse classique en pédologie (pH H2O et KCl, carbonates, granulométrie, COT, CEC, …), la détermination des formes du phosphore (total, minéral, organique ou disponible), des teneurs totales en éléments traces métalliques, la mesure de paramètres physiques ou hydriques tels que les limites d’Atterberg ou les courbes pF, ainsi que diverses analyses par spectroscopie proche infrarouge. Parmi les mesures envisagées à l’avenir, citons des analyses minéralogiques et des mesures de stabilité structurale. [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of Grand-Duchy of Luxembourg
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 23)

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In ... [more ▼]

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In order to understand the SWD variability and its influence on winter wheat disease, the objective of this study was to (i) determine the sensitivity of our model on varying input plant parameters and (ii) to evaluate the influence of simulated SWD to meteorological variations in three different climatic regions of the Grand-Duchy of Luxembourg (EVERLANGE, OBERCORN and SCHIMPACH). In this work, an agrometeorological model known as the Surface Wetness Energy Balance (SWEB) was applied for the simulation of SWD. The model was previously applied in another study for winter wheat cultivars and was adapted for use with agrometeorological data easily available from standard meteorological monitoring stations. Based on weather data and simulated SWD data, sensitivity analyses were performed to compare the effects of relative humidity, air temperature, wind speed and net radiation on wetness duration over one growing season (March-July) at three test sites. The results indicated that the sensitivities were very similar at three sites and there was no spatial trend (i.e. difference between locations) in the sensitivities. However, the model is most sensitive to relative humidity and differences between 0.5 and 25 h (per month) SWD were found when increasing/decreasing relative humidity by 10%. The model was least sensitive to changes in air temperature, showing differences of only 0.5–2 h (per month) in SWD. Intermediate sensitivity is found for rainfall, net radiation and wind speed. Among the input plant parameters values, SWD was most sensitive to the maximum fraction of canopy allowed as wet surface area, leaf area index, maximum water storage per unit area and least sensitive to crop height. The sensitivity to parameter values was less important compared to the sensitivity to the meteorological variable relative humidity. [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of the Grand-Duchy of Luxembourg
Mahtour, Abdeslam; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 22)

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See detailFrozen Splash
Delon, Giles ULg; Terwagne, Denis ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that ... [more ▼]

We have studied the splashing dynamics of water drops impacting granular layers. Depending on the drop kinetic energy, various shapes are observed for the resulting craters. Experimental parameters that have been considered are : the size of the millimetric droplets ; the height of the free fall, ranging from 1.5 cm to 100 cm ; and, the diam- eter of the grain. As the drop is impacting the sand layer, energy is dissipated and a splash of sand occurs. Meanwhile, surface tension, in- ertia and viscosity compete, leading to strong deformations of the drop which depend on the experimental conditions. Just after the drop en- ters into contact with the sand, imbibition takes place and increases the apparent viscosity of the fluid. The drop motion is stopped by this phenomenon. Images and fast-video recordings of the impact allowed to find scaling laws for the crater morphology and size. <br />This abstract is related to a fluid dynamics video for the APS DFD gallery of fluid motion 2010. [less ▲]

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See detailA fountain of droplets
Terwagne, Denis ULg; Delon, Giles ULg; Adami, Nicolas ULg et al

Poster (2010, November 21)

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges ... [more ▼]

A vessel is plunged upside down into a pool of 50 cSt silicone oil. An air bell is then created. This bell is vertically shaken at 60 Hz that leads to the oscillation of the air/oil interface. The edges of the immersed vessel generate surface waves that propagate towards the center of the bell. When the amplitude of the oscillation increases, wave amplitude increases. We study the influence of the angle between successive sides on the wave patterns. Two kinds of vessel have been studied: a triangular and a square prism. The shape of the air/oil meniscus depends on the angle between the sides of the considered prism. As the amplitude of the oscillation is increased, the triple line, which is the contact line between the solid and the air/oil interface, moves up and down. Above a given acceleration that depends on the immersion depth and on the shape vessel, wave goes under the corner edge of the bell. During the oscillation, the wave generates at the edges presents a singularity that leads eventually to a jet and a drop ejection. A drop is ejected at each oscillation. More complicated ejection can be produced with further increase of the amplitude. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailProjet thérapeutique n°99 "Personnes âgées"
Squelard, Gilles ULg; Vilain, Anne; Jacob, Bernard

Poster (2010, November 19)

ès avril 2011, la fonction de concertation fera l’objet d’un financement structurel pour les soins en santé mentale en Belgique. Cette fonction va se construire en partie sur base de l’expérience des ... [more ▼]

ès avril 2011, la fonction de concertation fera l’objet d’un financement structurel pour les soins en santé mentale en Belgique. Cette fonction va se construire en partie sur base de l’expérience des projets thérapeutiques « réseaux et circuits de soins ». Ces recherches actions se concrétisent par l’organisation de réunions de concertation pluridisciplinaires autour de situations chroniques et complexes. Plus spécifiquement, le projet thérapeutique n°99 « personnes âgées » a pour objectifs de favoriser le maintien à domicile de personnes âgées, de garantir la continuité des soins et du projet de vie, d’améliorer la qualité de la réintégration au domicile, d’éviter les réhospitalisations, de mieux cerner les conditions d’une réhospitalisation, et d’aborder les problématiques d’isolement, de solitude, voire de maltraitance. Objectif Communication de recommandations concernant l’organisation de réunions de concertation et la participation des intervenants sur base de l’expérience du projet thérapeutique n°99 « Personnes âgées » en Province de Liège. Méthodologie Le projet thérapeutique n°99 vise les personnes âgées de 65 ans et plus, habitant en Province de Liège et présentant une pathologie psychiatrique spécifique : démence, abus d’alcool, abus d’opiacés, abus d’hypnotiques, anxiolytiques ou sédatifs, schizophrénie, ou trouble schizo-affectif. Le projet repose sur une démarche empirique. Il consiste en l’organisation de réunions de concertation pluridisciplinaires autour de patients et de leur famille dont la finalité est la mise en place d’un suivi individualisé. Résultats L’âge moyen de la population suivie est de 79,21 ± 6.71. Elle se constitue majoritairement d’hommes (51%). Les diagnostiques les plus fréquents à l’inclusion sont la démence (Alzheimer, vasculaire,..) et l’abus d’alcool. Pour chaque situation, un agent de suivi est choisi. Son rôle sera de rester en contact avec l’usager et de faire le lien avec les différents intervenants. C’est également à lui que revient l’organisation des réunions de concertation. Cette tâche demande de tenir compte des emplois du temps des différents professionnels concernés. Les médecins sont des intervenants essentiels mais parfois difficile à mobiliser pour une réunion d’une heure. Le projet 99 arrive à des résultats satisfaisants quant à la participation des médecins tant d’un point de vue quantitatif que qualitatif. Nous avons pu dégager des pratiques facilitant leur participation en réunion de concertation. Enfin, l’agent de suivi est le garant de la place laissée à chacun pour s’exprimer lors de la réunion et en particulier à l’usager/famille. Des recommandations ont également pu être formulées à ce sujet. Discussion/conclusion L’expérience du projet thérapeutique n°99 s’est avérée extrêmement fructueuse, par l’atteinte des objectifs centrés sur l’usager et leur famille, mais également à travers les nombreux échanges interprofessionnels. La concertation pluridisciplinaire s’est avérée être un excellent moyen de découverte des partenaires, en amenant une représentation plus concrète de leur offre de soins et de leur mode de fonctionnement. [less ▲]

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See detailA mathematical model of calcium ion influence on the activity of osteogenic cells
Carlier, Aurélie ULg; Chai, Yoke Chin; Theys, Tina et al

Poster (2010, November 19)

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See detailGenital re-excretion of Murid gammaherpesvirus 4 following intranasal infection
François, Sylvie ULg; Vidick, Sarah ULg; Sarlet, Michaël ULg et al

Poster (2010, November 18)

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections ... [more ▼]

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections of immunocompetent hosts. Thus, infected individuals simultaneously both elicit antiviral protective immune response and secrete infectious virions. The best studied gammaherpesviruses are Human herpesvirus 4 and Human herpesvirus 8. As these viruses have no well-established in vivo infection model, related animal gammaherpesviruses are an important source of information. We are studying Murid herpesvirus 4 (MuHV-4), a virus that has originally been isolated from bank voles (Myodes glareolus). Although MuHV-4 has not been isolated from house mice (Mus musculus), infection of inbred laboratory mouse strains is commonly accepted as a good model for studying gammaherpesviruses in vivo. To date, it has however never been possible to monitor viral reexcretion and virus transmission in this species suggesting that this model could be imperfect. In order to identify potential re-excretion sites, intranasally infected mice were followed through global luciferase imaging for up to six months after infection. By this technique, we were able to detect appearance of viral replication in mice genital tract at various times post-infection. Typically, it firstly occurred between days 20 to 30 after infection, a period at which it is admitted that latency is established. Ex vivo imaging, quantitative PCR and immunohistochemistry helped us to determine that virus genomes were present in high quantity in the vaginal tissue and that viral replication occurred mainly at the vaginal external border. Finally, we highlighted the presence of free infectious viruses in the vaginal cavity at the moment of the observation of viral replication. In conclusion, we experimentally indentified for the first time a reexcretion site for MuHV-4 in mice that had been intranasaly infected. It therefore suggests potential genital transmission, either horizontal or vertical, of this virus in mice populations. In the future, these results could help us to better understand the biology of gammaherpesviruses but should also allow us to develop vaccinal strategies that could prevent the spread of these viruses in natural populations. [less ▲]

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See detailAuditory forebrain activation in the female canary is modulated by male song quality.
Barker, Jennifer ULg; Monbureau, Marie; Leboucher, Gerard et al

Poster (2010, November 17)

One of the chief functions of birdsong is to attract and stimulate females. In canaries (Serinus canaria), specific phrases (“A” phrases) sung by males have been identified as especially attractive for ... [more ▼]

One of the chief functions of birdsong is to attract and stimulate females. In canaries (Serinus canaria), specific phrases (“A” phrases) sung by males have been identified as especially attractive for females. These phrases unite a number of characteristics that are particularly difficult to combine, including large frequency bandwidth, high repetition rate and multiple-note syllables. Females exposed to “A” phrases produce more copulation displays and deposit more testosterone into their eggs. However, the neuroendocrine pathway underlying the translation of song audition to changes in testosterone deposition in yolks is not understood. Increased expression of several immediate early genes including c-fos and zenk (also called egr-1 in mammals) in other songbird species has been observed in the auditory forebrain of females hearing attractive song, and such differential activation may represent a first step in signal processing linking auditory input to egg testosterone deposition. Female canaries in breeding condition were exposed to 60 minutes of “sexy” song with a preponderance of “A” phrases, “non-sexy” song lacking “A” phrases, or white noise. Thirty minutes after the end of song playback, brains were collected, fixed in acrolein and sectioned and stained by immunohistochemistry for quantification of the Fos protein, an indicator of neuronal activity, in several regions involved in audition and auditory processing. The endocrine condition of each female was determined by measuring ovarian and oviduct weight at the time of autopsy. In the caudomedial mesopallium (CMM), Fos expression was higher in females that had heard sexy song than those that heard non-sexy song or white noise. Expression of Fos in the caudomedial nidopallium (NCM), the nucleus spiriformis medialis (SPM), the nucleus ovoidalis (OV), and the song nucleus HVC was unaffected by song quality. Thus differential auditory processing in the CMM may be an initial stage in the assessment by a female of song information to differential testosterone deposition in the egg. [less ▲]

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See detailBinding properties of clozapine and related compounds on native D2 dopamine receptors in normal and oxidative medium
Liégeois, Jean-François ULg; Dilly, Sébastien ULg

Poster (2010, November 16)

Despite the presence of several side effects, clozapine remains a valuable drug in treating schizophrenia. The presence of haematological toxicity was proposed to be related to the formation of nitrenium ... [more ▼]

Despite the presence of several side effects, clozapine remains a valuable drug in treating schizophrenia. The presence of haematological toxicity was proposed to be related to the formation of nitrenium species (1). Indeed, nitrogen derivatives like clozapine or olanzapine are very sensitive to oxidation while oxygen or sulphur isosteres such as loxapine, clothiapine and JL13, possess a very low sensitivity to oxidation (2-4). In the present study, we explore the impact of oxidation conditions on the binding of these drugs on native rat dopamine D2 receptors. Rats brains were quickly removed after cerebral dislocation and dissected on ice to get striata. After weighting, tissues were homogenized in buffer and washed three times by centrifugation. The final pellet was dispersed in the appropriate volume of incubation buffer (Tris 50 mM, MgCl2 5 mM, EDTA (Na2) 1 mM buffered at pH 7.4 with 4N HCl) depending on the experimental conditions. In oxidative conditions, horseradish peroxidase (1.25 µg/tube) and H2O2 (50 µM) were added to the incubation buffer. [3H]-Spiperone was used as radioligand and the non specific binding was determined in the presence of haloperidol (10 µM). Incubation temperature and time were 27°C and 60 min respectively. Competition experiments were done with different molecules such as haloperidol and various tricyclic derivatives. In our previous studies (2,3), we had observed that compounds like clozapine or olanzapine are significantly affected by oxidative conditions. In the present report, we show that this sensitivity is also associated with a dramatic decrease of binding affinity. Unlike such diazepine analogues, the binding of loxapine and JL13, two oxygen isosteres is slightly affected in oxidative conditions. Firstly, these results show that the distal nitrogen is not affected by the oxidative conditions. Secondly, the nitrenium formation (1) might lead to a tridimensional change that would reduce the interactions in the binding pocket. The oxidative effect of HRP/H2O2 mixture can be prevented by addition of ascorbic acid to the incubation medium. Thus depending on the oxidant character of the extracellular medium in physiological or pathophysiological conditions, interaction of molecules with different targets can be modified significantly. [less ▲]

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See detailInfluence of brain-derived neurotrophic factor val66met human polymorphism on declarative memory consolidation
Mascetti, Laura ULg; Foret, Ariane ULg; Matarazzo, Luca et al

Poster (2010, November 15)

The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain regulates long-term potentiation. In humans, valine (val) to methionine (met) substitution in the 5’ pro-region of ... [more ▼]

The Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin which in the adult brain regulates long-term potentiation. In humans, valine (val) to methionine (met) substitution in the 5’ pro-region of the BDNF protein is associated with poorer episodic memory. Neurons transfected with met-BDNF-Green Fluorescence Protein showed lower depolarization-induced secretion, while constitutive secretion is unchanged. Here, we hypothesized that the differences in BDNF release determined by this polymorphism would influence memory consolidation and that in comparison with the val/met (=val/met or met/met), val/val individuals would show higher memory performance and different brain responses during a 16h-delayed rather than immediate retrieval session. Participants encoded a series of neutral faces in the afternoon. Retrieval sessions took place one hour after the encoding session, and in the following morning, during the acquisition of functional Magnetic Resonance Imaging (fMRI) time series with a 3 Tesla Allegra scanner. During retrieval, studied faces and new ones were presented in random order. For each stimulus, the subjects indicated whether they could retrieve the encoding episode with (“Remember”), or without details (“Know”), or if they thought the item had not been presented during encoding (“New”). A repeated-measure ANOVA on discrimination index (d’) showed significant effects of group (F(1, 27)=8.65, p=0.007, n(val/val)=14, n(val/met)=15) and session (F(1, 27)=24.64, p=0.000), although the group by session interaction was not significant (F(1, 27)=1.29, p=0.267). fMRI results showed a significant genotype (val/val > val/met) by session (delayed > immediate retrieval) by memory type (Remember > Know) interaction in the right inferior occipital gyrus (x=42, y=-78, z=0, p=0.004, Z=3.77), the left inferior parietal lobule (x=-56, y=-40, z=48, p=0.013, Z=3.43), the posterior cingulate cortex (x=14, y=-42, z=42, p=0.019, Z=3.29) and the right hippocampus (x=28, y=-22, z=-22, p=0.03, Z=3.11). Val/val individuals demonstrate higher memory performance than met-carriers but the change in memory performance between immediate and delayed retests is similar in both allelic groups. In contrast, neural correlates of recollection change between sessions differently according to genotype: responses increase significantly more in val/val than in val/met individuals in brain areas involved in the retrieval, accumulation and binding of perceptual memory details during delayed, relative to immediate retest. These data suggest that activity-dependent BDNF release promotes memory consolidation during the first post-training hours. [less ▲]

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See detailNeural correlates of cognitive control at the item level in the Stroop task.
Grandjean, Julien ULg; D'Ostilio, Kevin ULg; Fias, Wim et al

Poster (2010, November 15)

Detailed reference viewed: 25 (1 ULg)
See detailGestion des zones d'activité économique existantes. Gestion parcimonieuse du sol et mixité raisonnée des fonctions
Girolimetto, F.; Labeeuw, F.-L.; Lambotte, Jean-Marc ULg et al

Poster (2010, November 08)

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See detailL'agame papillon géant, Leiolepis guttata (Cuvier, 1829), adapté à l'herbivorie, se nourrit-il également d'insectes ?
Tran, Tinh ULg; Rochette, Anne-Julie; De Martynoff, Abigail et al

Poster (2010, November 06)

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See detailL'entomologie forensique: c'est quoi?
Frederickx, Christine ULg; Dekeirsschieter, Jessica ULg; Haubruge, Eric ULg

Poster (2010, November 06)

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See detailAMYLOLYSIN, A LANTIBIOTIC PRODUCED BY BACILLUS AMYLOLIQUEFACIENS GA1.
Arguelles Arias, Anthony ULg

Poster (2010, November 05)

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See detailInterests of using a regional model to forecast wind power production
Doutreloup, Sébastien ULg

Poster (2010, November 05)

European policies have decided to reduce the greenhouse gas emissions of 20% and to reach 20% of renewable power production by 2020. Increasing wind power is one of the numerous solutions to reach these ... [more ▼]

European policies have decided to reduce the greenhouse gas emissions of 20% and to reach 20% of renewable power production by 2020. Increasing wind power is one of the numerous solutions to reach these goals. However, this kind of energy production depends on the meteorological conditions and gives it an intermittent behaviour. The wind speed variations cause voltage and frequency fluctuations that are unacceptable for the power grid. Therefore, forecasting production will become essential with the aim of integrating this kind of energy production into the power grid. We have developed and compared two forecasting models which give as outputs the wind power production every 15 minutes over the Belgian territory: the first one uses the outputs from the global model GFS (available at a horizontal resolution of 0.5° every 3h) and the second one uses the regional climate model WRF-NMM (using a horizontal resolution of 4km). Both of these models predict the wind speed and transform wind speed into wind power production, using a power curve which depends on the wind turbines and their characteristics. The first model using the GFS outputs is not precise enough in space and time to correctly forecast the wind speed in punctual wind farms. That is why we apply some specific tunings on these forecasts. These tunings depend on the air density, the wind direction and the stability of the air mass. The second model using the WRF-NMM outputs runs over the Belgian territory. Initial conditions are forced by the GFS outputs at 0.5° and WRF computes a physical based spatio-temporal downscaling of the meteorological variables. The outputs have a spatial resolution of 4 km and a time resolution of 15 minutes. Some tunings are also needed to adjust the wind power forecasts by comparison to the wind power observations. We present here some results of both models and the interest of using a regional model for more precise wind power forecasting. [less ▲]

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See detailHigh resolution modelling of the Greenland ice sheet surface mass balance using the regional climate model MAR coupled with a downscaling interface
Franco, Bruno ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2010, November 05)

We are developing a coupling interface downscaling the 25km-atmosphere fields simulated by the regional climate MAR (Modèle Atmosphérique Régional) model onto a 5km-grid in order to resolve the surface ... [more ▼]

We are developing a coupling interface downscaling the 25km-atmosphere fields simulated by the regional climate MAR (Modèle Atmosphérique Régional) model onto a 5km-grid in order to resolve the surface processes at high resolution with the SISVAT (Sea Ice Soil Vegetation Atmosphere Transfer) snow-ice module. This coupling interface improves the representation of the topography and ablation zone of the Greenland ice sheet (GrIS) in the MAR model, and therefore will provide higher resolution estimations of the GrIS surface mass balance (SMB) without additional computing time. By using outputs from previously-gauged global circulation models (GCM) as forcing fields, the MAR model coupled with the downscaling interface will then perform 5km future simulations of the GrIS SMB for different IPCC greenhouse gas emissions scenarios for the 21st century. [less ▲]

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See detailFunctional and physicochemical properties of starches isolated from sorghum cultivars cultivated in algerian hyperarid regions
Boudries, Nadia; Sindic, Marianne ULg; Belhaneche, Naima et al

Poster (2010, November 03)

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See detailSéchage convectif d’un milieux poreux humide. Obtention des coefficientS des echanges de surface
Kahlerras, Loubna ULg; Belhamri

Poster (2010, November 03)

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le ... [more ▼]

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le transfert de chaleur et de masse dans un milieu poreux, ayant les caractéristiques du béton renforcé avec des coupeaux de bois. Pendant l'opération de séchage, beaucoup de problèmes sont produits comme consommation d'énergie élevée, cinétiques du séchage et le changement de la forme finale du produit. En fait l'amélioration de la technique du séchage devient une nécessité. Parmi les auteurs qui ont approché ce problème, nous pouvons citer les travaux de [1], [2], [3], [4], [5]. Le but est donc analysé le comportement hydrique du milieu poreux, montrer l’effets de la variabilité du coefficient d’échange massique sur le transfert de masse à l’intérieur du milieu poreux et aussi l’effet de certains paramètres pertinents du matériau comme l’humidité initiale, sur le processus du séchage. [less ▲]

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See detailMolecular analysis of the FOLR genes in patients with cerebral folate deficiency
SEGERS, Karin ULg; Hanson, J; RAMAEKERS, Vincent ULg et al

Poster (2010, November 02)

Detailed reference viewed: 9 (0 ULg)
See detailKisspeptin in the developing and adult rat brain
Desroziers, Elodie ULg; Mikkelsen, Jens; Caraty, Alain et al

Poster (2010, November)

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See detailThe Tibetan Singing Bowl
Terwagne, Denis ULg; Bush, John

Poster (2010, November)

The Tibetan singing bowl is a type of standing bell. Originating from Himalayan fire cults as early as the 5th century BC, they have since been used in religious ceremonies, for shamanic journeying, exor ... [more ▼]

The Tibetan singing bowl is a type of standing bell. Originating from Himalayan fire cults as early as the 5th century BC, they have since been used in religious ceremonies, for shamanic journeying, exor- cism, meditation and shakra adjustment. A singing bowl is played by striking or rubbing its rim with a wooden or leather-wrapped mallet. The sides and rim of the bowl then vibrate to produce a rich sound. When the bowl is filled with water, this excitation can cause crispa- tion of the water surface that can be followed by more complicated surface wave patterns and ultimately the creation of droplets. We here demonstrate the means by which the Tibetan singing bowl can levi- tate droplets. This is a sample arXiv article illustrating the use of fluid dynamics videos. [less ▲]

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See detailEvolution des structures de sols sous itinéraires techniques contrastés : relation entre courbes de rétention et analyse par microtomographie aux rayons X
Beckers, Eléonore ULg; Roisin, Christian; Léonard, Angélique ULg et al

Poster (2010, November)

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were ... [more ▼]

Tillage reduction seems to affect porosity distribution, orientation and connectivity. Soil samples were removed from plots under conventional tillage or reduced tillage. Their water retention curves were measured, and the characterization of soils porosity was made using x-ray microtomography measurements. Results show differences in the meso as well as in the macroporosity. [less ▲]

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See detailChronologie de l’architecture médiévale et datation par luminescence : étude de l’église St-Irénée de Lyon (France)
Bouvier, Armel; Guibert, Pierre; Blain, Sophie ULg et al

Poster (2010, November)

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Peer Reviewed
See detailRaman spectroscopic study of complex formation between major calixarene derivatives and three pharmaceutical substances
Tiuca, Ioana; Mantanus, Jérôme ULg; Iacob, Bogdan et al

Poster (2010, November)

Complex formation of six calix[n]arene derivatives – tert-butyl-calix[4]arene (C4), tert-butyl-calix[6]arene (C6), tert-butyl-calix[8]arene (C8) and their ethyl-acetic-ester derivatives (C4Es4, C6Es6 ... [more ▼]

Complex formation of six calix[n]arene derivatives – tert-butyl-calix[4]arene (C4), tert-butyl-calix[6]arene (C6), tert-butyl-calix[8]arene (C8) and their ethyl-acetic-ester derivatives (C4Es4, C6Es6, C8Es8) – has been the subject for our Raman spectroscopic study. Substances taken in study for complexation were the two widely used anticoagulants – warfarin and its 5-nitro- derivative, acenocoumarol – and their antidote, phytomenadione (also known as phylloquinone or vitamin K1). For each standard substance, Raman spectra were studied between 3620 and 90 cm-1. In order to obtain the complexes, a mixture of solutions of each calixarene and each analyte was prepared, in a stoichiometric ratio of 1:1 and then the solvents were evaporated. Spectra of solid residues obtained were compared with those of initial molecules. In all cases, there was observed a Raman band shifting or even the disappearance of some bands, indicating that calixarene derivatives interact with the studied molecules. In conclusion, the six calixarene derivatives taken in study seem to be able to form complexes with the molecules of warfarin, acenocoumarol and phylloquinone. [less ▲]

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See detailAffine Warp Propagation for Fast Simultaneous Modelling and Tracking of Articulated Objects
Declercq, Arnaud ULg

Poster (2010, November)

We propose a new framework that allows simultaneous modelling and tracking of articulated objects in real time. We introduce a non-probabilistic graphical model and a new type of message that propagates ... [more ▼]

We propose a new framework that allows simultaneous modelling and tracking of articulated objects in real time. We introduce a non-probabilistic graphical model and a new type of message that propagates explicit motion information for realignment of feature constellations across frames. These messages are weighted according to the rigidity of the relations between the source and destination features. We also present a method for learning these weights as well as the spatial relations between connected feature points, automatically identifying deformable and rigid object parts. Our method is extremely fast and allows simultaneous learning and tracking of nonrigid models containing hundreds of feature points with negligible computational overhead. [less ▲]

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See detailSexually differentiated cell proliferation in the medial preoptic nucleus of Japanese quail
Mouriec, Karen ULg; Bardet, Sylvia; Balthazart, Jacques ULg

Poster (2010, November)

The androgen-depend sequence of male copulatory behaviors is sexually differentiated in Japanese quail like in many other vertebrates. This behavior disappears within a week after castration of males and ... [more ▼]

The androgen-depend sequence of male copulatory behaviors is sexually differentiated in Japanese quail like in many other vertebrates. This behavior disappears within a week after castration of males and is rapidly restored following treatment with testosterone. In contrast, ovariectomized females treated with testosterone never show these behaviors. This sex-specific responsiveness to testosterone results from organizational effects of embryonic ovarian estrogens. The behavioral phenotype of male and female quail is completely reversed by treatment, before embryonic day 12 (E12), of male embryos with estrogens or of female embryos with an inhibitor of aromatase, the enzyme converting testosterone into estradiol. In the quail brain, the medial preoptic nucleus (POM) is a necessary and sufficient site for the activation of sexual behavior by testosterone. It can be identified by a dense population of aromatase-immunoreactive neurons and, importantly, aromatase activity in this region is sexually differentiated (males>females) and this difference is maintained even when birds are treated with a same dose of testosterone. Aromatase is thus, like sexual behavior, a sex-specific feature regulated by testosterone in adult quail and presumably organized in early life by steroid action. The cellular basis of these organizational processes have not been identified. We analyzed the ontogeny of POM cells by injecting 5-bromo-2-deoxyuridine (BrdU) in eggs at different embryonic (E) stages (E8, E10, E12, E14 and E16) and quantifying BrdU-labeled cells at postnatal (PN) day 56. Large numbers of BrdU-positive cells were observed throughout the POM of males and females injected on E8-E10 but most cells were post-mitotic in both sexes on E14-E16. E12 injections resulted in a larger number of BrdU cells in females than in males at PN56. However, male and female embryos injected on E12 and killed on E13, PN1 or PN15 had similar numbers of BrdU positive cells. Furthermore, BrdU injections on E14 labeled very few cells at PN 56 suggesting that the POM is essentially post-mitotic at that age. Together these data suggest that a sex-specific apoptosis must occur between PN15 and PN56. Double-label immunohistochemistry for BrdU and for the neuron-specific marker Hu indicated that BrdU-positive cells born between E8 and E16 are not neurons and are thus presumably glial cells. This sex-specific cell proliferation occurring around the end of the critical period of sexual differentiation may have an important impact on brain and behavior differentiation. The phenotype of these cells and the mechanisms mediating their differential development are currently under investigation. [less ▲]

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See detailMicro-catchments classification: a tool for mud flow mitigation
Degre, Aurore ULg; Mokadem, Abdel Ilah; Cordonnier, Hélène et al

Poster (2010, November)

Hydrologic similarities between catchments can be of use in the context of overland flood and mud flow hazards management. In Wallonia, upstream micro-catchments were mapped for each runoff concentration ... [more ▼]

Hydrologic similarities between catchments can be of use in the context of overland flood and mud flow hazards management. In Wallonia, upstream micro-catchments were mapped for each runoff concentration axis. The outlets of these catchments are considered at the point where water reaches the permanent river stream. No less than 145 547 micro catchments were mapped in Wallonia (16900 km²). Their area varies between 1 and 1233 ha (mean area: 7.8 ha). A data base was built up to synthesize their major characteristics like e.g. area, shape and mean slope. No clear classification appeared. At this stage, it became obvious that the major components of these catchments had to be handled simultaneously from a hydrological point of view in order to produce a clear classification. The main hydrologic significant data are available in Wallonia: the digital soil map at 1/20 000 scale, the DTM (raster file of 10 meters resolution), digital land use at 1/10 000 scale and spatial statistics for rain (IDF curves for each commune). A hydrologic model was developed using the python programming language in the ArcGis 9.3 environment. This model is based on the NRCS – USDA method. Rain abstraction is calculated on the basis of a CN (curve number) which integrates the soil type, the land use and the slope. Water transfer is computed using a convolution based on triangular unit hydrogrammes. This calculation includes the concentration time which integrates the catchment morphology (shape and slope) and the land use (roughness). The MUSLE equation is also computed in order to handle the sediment problem. The results consist in a full project hydrograph, peak flow value, flood water volume and sediment quantification in response to a project rainfall. The CN and MUSLE semi-empirical methods are validated at larger scale in Wallonia but have still to demonstrate their efficiency at the micro-catchment scale. Nevertheless, the aforementioned variables can be considered as integration factors of the whole hydrological context of the micro-catchments. It allows us to build advice on overland flow and mud flow mitigation at watershed scale. This approach can also be of help to compare ungauged micro-catchments between each other and possibly transpose the soil conservation practices from a site to another. [less ▲]

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See detailNano-ultrasonics sensors
Arca, Ahmet; Dispas, Amandine ULg; Jamie, Twycross et al

Poster (2010, November)

Ultrasound is a powerful tool for diagnosing medical and mechanical problems. Conventional ultrasonics work at megahertz frequencies and with wavelengths of 1-2mms to 10’s mm. This means it cannot "see ... [more ▼]

Ultrasound is a powerful tool for diagnosing medical and mechanical problems. Conventional ultrasonics work at megahertz frequencies and with wavelengths of 1-2mms to 10’s mm. This means it cannot "see" very small objects at the nanoscale. Our new transducers are so small it is impractical to communicate with them electrically. Instead we have devised a non contact method of talking to them using short pulses of laser light. We have adopted two approaches for producing these transducers, one method builds plates devices the other uses self assembled nanoparticles. The transducers are made from alternating metal and soft transparent layers. They have optical and mechanical resonances and so the devices have to be made such that they work well both mechanically and optically [less ▲]

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See detailFine Mapping of a large-effect QTL for scab resistance co-localising with the major gene RVI6 (Vf).
Verdu, Cindy ULg; Lasserre, Pauline; Durel, Charles-Eric

Poster (2010, November)

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See detailA percepção da expressão físico-motora por professors do ensino basico
do Couto, Joao; Cloes, Marc ULg; Sequeira, Pedro

Poster (2010, November)

This poster proposes the findings of a study aiming to identify the representations of elementary school classroom teachers about physical education.

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See detailSynthesis of core cross-linked micelles for the development of new drug delivery systems
Cajot, Sébastien ULg; Danhier, F.; Lautram, N. et al

Poster (2010, October 29)

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See detailKashin-Beck Disease: evaluation of mineral intake in young Tibetan children from endemic areas
DERMIENCE, Michael ULg; Maesen, Philippe ULg; Mathieu, Françoise et al

Poster (2010, October 26)

Kashin-Beck disease is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. Although many ... [more ▼]

Kashin-Beck disease is an endemic and chronic osteochondropathy. This disease principally occurs in the Tibet Autonomous Region and in several provinces of the People’s Republic of China. Although many studies have already been conducted and many others are still underway, its ethiology remains unknown. A multifactorial hypothesis has been proposed: selenium deficiency, high concentration of organic matters in drinking water (fulvic acids) and mycotoxin poisoning by fungi infecting cereals. This original study aimed to measure the mineral contents of the food most often consumed in severe endemic regions and then to evaluate the daily intake of minerals in young Tibetan children from endemic areas. The mineral elements were selected in relation to their implications in bone metabolism. A sampling campaign split up into two time periods (winter and spring) was carried out. Ten families from two distinct regions were selected based on three criteria: they live in endemic areas; they include a 3 to 5 year-old child; this child has a KBD brother or sister. At the same time, a nutritional survey was made by the means of a prospective questionnaire in order to list the 24h food intake of the 3 to 5 year-old child. This survey highlighted the extremely monotonous cereal-based Tibetan diet. An analytical method for the minerals was developed as follows: mineralization of samples performed by microwave-assisted wet process; mineralized solutions measured by several atomic absorption or emission spectrometric methods and molecular absorption spectrometric methods. The analytical method was validated by mean of certified reference materials. Mean food contents were calculated and compared to food composition reference tables. High iron contents and selenium deficiencies were highlighted in several foods. Daily intakes were estimated combining mineral measurements and nutritional survey results. These were compared to dietary reference intakes from reference tables. This estimation reveals some crucial points: we confirm a marked deficiency in calcium; Ca/P ratios are always low; iron and copper intakes are excessive; zinc is the most probably deficient; while selenium could be deficient; manganese intakes often exceed toxicity thresholds. Nevertheless, this study encounters some limits. The bioavailability of minerals is a critical point that deserves further investigations. Moreover, a larger study over a longer term covering both endemic and non-endemic regions is required for definite conclusions to be reached. [less ▲]

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See detailAdaptive reflective processes using the IMS-LD specification
Verpoorten, Dominique ULg; Kelle, S

Poster (2010, October 26)

The research work presented in this poster coins a new range of reflection support tools called "REFLECTION AMPLIFIERS", viz. deliberate and well-considered prompting approaches that offer learners ... [more ▼]

The research work presented in this poster coins a new range of reflection support tools called "REFLECTION AMPLIFIERS", viz. deliberate and well-considered prompting approaches that offer learners structured opportunities to examine and evaluate their own learning. [less ▲]

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See detailInterest of routine dosage of meropenem in difficult to treat infections
Frippiat, Frédéric ULg; Bensahi, Ilham; Denooz, Raphael ULg et al

Poster (2010, October 23)

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See detailThe role of meiofauna in energy transfer in a Mediterranean seagrass bed (Calvi, Corsica)
MASCART, THIBAUD; Lepoint, Gilles ULg; Borges, Alberto ULg et al

Poster (2010, October 22)

Meiofaunal communities of the endemic Mediterranean seagrass, Posidonia oceanica, were sampled in five different habitats characterised by different degradation level of macrophytodetritus. In term of ... [more ▼]

Meiofaunal communities of the endemic Mediterranean seagrass, Posidonia oceanica, were sampled in five different habitats characterised by different degradation level of macrophytodetritus. In term of abundance, harpacticoid copepods represent half of the community followed by nematodes and polychaetes. Two meiofauna communities were distinguished: (1) a benthic community of meiofauna, living in the sediment or on highly fragmented macrophytodetritus, and (2) a foliar, epiphytal community associated with seagrass leaves and low fragmented macrophytodetritus leaves. They differed significantly in their harpacticoid copepod family composition. The benthic community consisted mainly of families like Tisbidae and Miraciidae, while the epiphytal community was dominated by families like Thalestridae and Laophontidae. These differences in composition may also imply a differential functional diversity. Trophic biomarkers (stable isotopes, fatty acids) were used to identify the major sources of organic matter contributing to the copepods diet and hence to gain insight in the overall carbon flux. Harpacticoid copepods showed preferences to feed upon the epiphytal biofilm community composed of bacteria, diatoms, fungi and microalgae. Copepods used the seagrass and detritus material merely as substrate, but were attracted to the biofilm rather than the plant material which is rich in structural carbohydrates difficult to assimilate by animals (i.e. lignin, cellulose, ...). Since harpacticoid copepods showed to use different sources of carbon, unravelling the contribution of each of them and the role of the degradation level of the detritus for food selectivity is the next step forward. [less ▲]

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See detailImpact of grazing by amphipods on the epiphytic cover of the Posidonia oceanica leaves: an in situ experiment.
Michel, Loïc ULg; Dupont, Alessandra; Gobert, Sylvie ULg et al

Poster (2010, October 22)

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled ... [more ▼]

It is now established that several species of amphipods associated to Mediterranean Posidonia oceanica meadows consume the macro-epiphytes present on the leaves of the seagrass. Moreover, under controlled in vitro conditions, three amphipod taxa (Apherusa chiereghinii,Dexamine spiniventris and Gammarus spp.) are able to drastically deplete the biomass of erected algae, thus influencing the epiphytic cover in both a quantitative and a qualitative way. Here, we tried to assess whether this strong and complex trophic interaction was realized in the field. We designed an in situ experiment that used microcosms placed directly in the meadow, at a depth of 10m, to estimate the impact of grazing by the aforementioned amphipod taxa on the dynamics of the epiphytic cover. Both Gammarus spp. and Dexamine spiniventris caused a significant decrease of the biomass of erected algae and erected animals (bryozoans and hydrozoans). Impact of grazing by Apherusa chiereghinii on these two epiphytic groups was less important, although strong but marginally non-significant (0,1>p>0,05) trends to lower biomasses were present. None of the considered taxa seemed to consume encrusting macro-epiphytes. In addition, assimilation of epiphyte-derived carbon and nitrogen by grazers was monitored using stable isotopes (13C and 15N), and epiphyte elemental content (C & N) was measured. Our results shed light on trophic interactions between the amphipods from Posidonia oceanica meadows and the seagrass epiphytic cover, and thus enhance our understanding of the role of these grazers in the functioning of the meadow as an ecosystem. [less ▲]

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See detailSPATIO-TEMPORAL LOCALIZATION OF BETA TUBULIN III IN THE ORGAN OF CORTI AND IN THE SPIRAL GANGLIA BETWEEN THE EMBRYONIC DAY (E18) AND THE POST-NATAL DAY (P25) IN RAT.
Johnen, Nicolas ULg; Thelen, Nicolas ULg; Cloes, Marie ULg et al

Poster (2010, October 22)

The mammalian auditory organ, the organ of Corti (OC), is composed of mechanosensory hair cells and nonsensory supporting cell types. Based on their morphology and physiology, at least two types of ... [more ▼]

The mammalian auditory organ, the organ of Corti (OC), is composed of mechanosensory hair cells and nonsensory supporting cell types. Based on their morphology and physiology, at least two types of sensory cells can be identified in the OC: inner and outer hair cells. The structure of this organ is well reported in adult but its development is still little-known. By using confocal microscopy, we studied the spatial-temporal distribution of beta tubulin III during the differentiation of the OC in rat from the embryonic day 18 (E18) to the postnatal day (P25). The beta tubulin III is typical for neural cells in the OC. We observed that beta III tubulin is present in the extensions innerving the row of inner hair cells at E18. At E19, the extensions innerving the inner hair cells and the two first rows of outer hair cells were immunolabelled. From E21 to P25, all of hair cells were connected to the spiral ganglion. In the latter, the intensity of immunolabelling decreased between E18 to P25 and the labelling only concerned some cells. These results reveal that beta III tubulin appears before birth in the nervous extensions connecting the sensory cells of the OC according to a modiolar-to-striolar gradient. In the spiral ganglia, the labelling progressively decreases during its development. [less ▲]

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