References of "Poster"
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See detailMid and late Holocene dust deposition in Western Europe: The Misten peat bog (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Le Roux, Gael; Piotrowska, Natalia et al

Poster (2012, June)

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the ... [more ▼]

Multi-proxy climate recorded from peatlands have been used to tracer the climate change during the Holocene. The initiation of peatland may be related to a change to colder and or wetter climate, and the variations in peat composition reflect changes in precipitation and temperature. Peat has been used as an archive to reconstruct climate change over the Holocene (e.g., Shotyk et al., 1998; Sapkota et al., 2006). To characterize the climate in Belgium, a 570 cm-long core from Misten peat bog was studied. Several radiocarbon ages allow to define an accurate age model, the peat core represents 5500 years of record. The analyses of REE and lithogenic element contents, as well as the Nd isotopes, were performed by HR-ICP-MS and MC-ICP-MS. Peat humification, C/N ratio, ash content and bulk density were used to evaluate local hydroclimatic conditions. The dust deposition ranges from 0.03 to 4 g m -2 yr -1. As a first observation the highest rates of atmospheric dust deposition correspond to cold periods. The Nd values show large variability, between +1 to –22, identifying three major sources of dusts falling into the peat: local soils, distal volcanic and desert particles. Further studies are in progress to better identify the main forcing factor on the evolution of the atmospheric dust deposition over the Holocene. [less ▲]

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See detailNon-destructive characterization of the Nizet Manuscript (XVIIIth century) : first results
Machowski, Mélanie ULg; Calvo Del Castillo, Helena ULg; Hocquet, François-Philippe et al

Poster (2012, June)

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See detailDerivation of a new lamb survival trait for implementation in the New Zealand sheep industry
Vanderick, Sylvie ULg; Auvray, Benoit; Newman, Sheryl-Anne et al

Poster (2012, June)

Lambing percentage is one of the most significant factors affecting profitability on New Zealand sheep farms. Since the early 1990s, lambing percentage has increased at about 1% per year from a relatively ... [more ▼]

Lambing percentage is one of the most significant factors affecting profitability on New Zealand sheep farms. Since the early 1990s, lambing percentage has increased at about 1% per year from a relatively stable level of approximately 100%, and top performing sheep farms are now consistently achieving 150% or more. As lambing percentage increases, the proportion of ewes bearing twins and triplets increases accordingly. Lamb mortality rate in these multiples is higher than in singles, with triplets being particularly susceptible. Consequently, lamb survival has become increasingly important to the New Zealand sheep industry. Sheep Improvement Ltd (SIL, New Zealand's national sheep genetic evaluation system provided by Beef & Lamb NZ) records lamb survival to weaning but genetic improvement has been limited due to the low heritability of the trait and the current method of recording. [less ▲]

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See detailMitochondrial Proteomics of a Secondary Green Alga
Perez, Emilie ULg; Degand, Hervé; Morsomme, Pierre et al

Poster (2012, June)

Euglena gracilis is an alga that derives from a secondary endosymbiosis with a green alga. Our general objective is to study the interactions established between the chloroplast and the mitochondrion ... [more ▼]

Euglena gracilis is an alga that derives from a secondary endosymbiosis with a green alga. Our general objective is to study the interactions established between the chloroplast and the mitochondrion during the endosymbiosic event and to determine the phylogenetic origin of the genes encoding the proteins involved in these interactions. As a first step, we performed a high-throughput analysis of the mitochondrial proteome of Euglena gracilis. Our MS/MS experiments mostly recover mitochondrial proteins representing 15 mitochondrial pathways, which indicates that our mitochondrial extracts are relatively pure, but the phylogenetic origins of the corresponding genes are surprisingly diverse. [less ▲]

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See detailThe influence of the token frequency on the generalization of construction schemas in French-speaking children with SLI
Leroy, Sandrine ULg; Parisse, Christophe; Moulin, Mélissa et al

Poster (2012, June)

Constructivist approach (Goldberg, 1995 ; Tomasello, 2003) postulates that children build their linguistic system from their own linguistic experience. To be productive with their language, children have ... [more ▼]

Constructivist approach (Goldberg, 1995 ; Tomasello, 2003) postulates that children build their linguistic system from their own linguistic experience. To be productive with their language, children have to generalize construction schemas to never heard items. Because children with SLI seem to show limited morphosyntactic creativity and variability, we hypothesize that they would have difficulties to generalize their construction schemas what would hinder their access to the most abstract level of their linguistic competence. Given this lack of productivity of construction schemas in children with SLI, they would produce more lexicalized forms than abstract form what would lead to a limitation of the linguistic competence. The aim of our study was to test if children with SLI had more difficulties than children with typical language development (TLD) to generalize a schema to new items. Given the role of the token frequency in the abstraction of construction schemas (cf. Bybee, 1995), we decided to create a task in which we manipulated this variable. [less ▲]

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See detailTHREE NEW BCCM PUBLIC COLLECTIONS ON DIATOMS, MYCOBACTERIA AND CYANOBACTERIA
Rigouts, Leen; Vanormelingen, Pieter; Vyverman, Wim et al

Poster (2012, June)

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See detailRoles of Fgf receptors in cranial cartilage formation in zebrafish
Larbuisson, Arnaud ULg

Poster (2012, June)

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See detailPegase modelling studies applied to micropollutants: use cases
Grard, Aline ULg; Everbecq, Etienne ULg; Deliège, Jean-François ULg

Poster (2012, June)

For the last years, PEGASE model has been used in two studies aiming at better assessment of the source and behaviour of micropollutants in the rivers network. In the first study, with financial support ... [more ▼]

For the last years, PEGASE model has been used in two studies aiming at better assessment of the source and behaviour of micropollutants in the rivers network. In the first study, with financial support from INERIS1, the PEGASE model has been used to simulate the fate of micropollutants (Cd, Zn & Cu) within the basins of the Meuse and the Adour. The choice of the modelled micropollutants and sub-basins has been performed in agreement with INERIS, the involved Water Agencies and the Aquapole. A major selection criterion was the availability of data (discharges and in-situ measurements). For the second study, the PEGASE model has been adapted to describe the cocaine fate (or rather one of its stable metabolite: benzoylecgonine–BZE) in surface water. The BZE has been added to the model as an additional micropollutant, thanks to the implementation of a new state variable. Simulations of BZE have been done in Belgium, where many measurements from the COWAT project [3] were available. The first results show a good matching between calculated and measured values. The ability of the model to simulate the fate of micropollutants (including emerging substances) within surface water has been demonstrated, but still requires enhancements and extension to other substances and sub-basins. In addition, these studies have shown the huge work remaining in discharge inventories. [less ▲]

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See detailWheat disease forecasting using weather radar observations
Mahtour, Abdeslam; El Jarroudi, Moussa ULg; Delobbe, Laurent et al

Poster (2012, June)

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See detailTrunk and knee performance of rowers
GROSDENT, Stéphanie ULg; Demoulin, Christophe ULg; Gauthier, Stéphanie et al

Poster (2012, June)

This study showed some difference in trunk and knee extensors strength between rowers and control subjects as well as between rowers and non-rowing athletes. The increased performances of extensor muscles ... [more ▼]

This study showed some difference in trunk and knee extensors strength between rowers and control subjects as well as between rowers and non-rowing athletes. The increased performances of extensor muscles in elite rowers appear to be probably related to the specificity of this sport. In the drive phase of rowing, rowers sequentially push with the legs and then pull with the arms and lower back, requiring both muscular strength and endurance. However, no difference was shown between groups regarding dynamic and static trunk extensor endurance. Further study is required to clarify if trunk and knee muscle strength and/or endurance are related to rowing performance. [less ▲]

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See detailAnisotropy preserving interpolation of diffusion tensors
Collard, Anne ULg; Bonnabel, Silvère; Phillips, Christophe ULg et al

Poster (2012, June)

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See detailThe effects of aging on verbal short-term memory and word production capacities
Verhaegen, Clémence ULg; Poncelet, Martine ULg

Poster (2012, June)

The effects of aging on verbal short-term memory (STM) are still a matter of debate (e.g., Nilsson et al., 2003). Recent models of STM distinguish processes involved in the retention of item information ... [more ▼]

The effects of aging on verbal short-term memory (STM) are still a matter of debate (e.g., Nilsson et al., 2003). Recent models of STM distinguish processes involved in the retention of item information (i.e., the identity of words) and order information (i.e., the order of presentation of items) (see Majerus, 2008, for a review). Finally, these models also incorporate relationships between STM and word production capacities, which are often impaired in aging (Burke et al., 1991). The aims of this study are (1) to explore the effects of aging on both item and order STM capacities, (2) to explore the effects of aging on naming capacities and (3) to explore the relationships between STM and naming in aging. Three groups of participants participated in the present study: (1) 56-64 years old (N=26) – (2) 65-74 years old (N=23) – (3) 75-84 years old (N=22). The participants' hearing thresholds were analyzed with a pure tone audiometer. The participants were asked to perform STM tasks and a picture naming task. The results confirm the presence of naming difficulties in participants above 65 years of age, as previously shown by Verhaegen and Poncelet (in press). By contrast, in STM, the differences become non significant when the hearing status is controlled for. However, the items are presented auditorily in all STM tasks. Therefore, in order to confirm the absence of age-related differences in STM, it would be of interest to assess the participants with visual STM tasks. [less ▲]

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See detailImpact of performance anxiety on the accuracy of the singing voice among music students
Larrouy, Pauline ULg; Clijsters, Céline; Morsomme, Dominique ULg

Poster (2012, May 31)

Performance anxiety causes physical and cognitive symptoms. This emotional state can affect the vocal features thus the fundamental frequency which is the main parameter to evaluate the singing voice ... [more ▼]

Performance anxiety causes physical and cognitive symptoms. This emotional state can affect the vocal features thus the fundamental frequency which is the main parameter to evaluate the singing voice accuracy. The aim of this study is to observe the impact of performance anxiety on the singing voice accuracy. 31 music students from the Royal Conservatories of Belgium sang a melody three times. Twice in quiet situations and one time in a stress situation (the day of the examination). This performance was rated by a panel of teachers. The anxiety level was controlled by measuring the heart frequency. We analyzed errors concerning the interval accuracy and the respect of the tonal center. We observe that the heart frequency is significantly higher in the stress situation (F(2,28)=15,18 ; p<.001), especially for advanced students. The students have difficulty to maintain the tonal center (F(2,12)=7,17 ; p=.03), whereas the accuracy of the intervals is not altered (F(2,12)=1,1 ; p=.56). The rating of the jury correlates with interval accuracy (r=-.411; p=.03) and respect of the tonal center (r=-.452; p=.016), particularly at the beginning of the melody (r=-.516; p=.005). To conclude, performance anxiety leads to an increase of the heart frequency and alters the respect of the tonal center. This is particularly the case for advanced students for whom this situation is a real challenge. [less ▲]

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See detailSeasonal and depth-related distributions of epiphytic Bryozoa in a Mediterranean seagrass meadow
Lepoint, Gilles ULg; Balancier, Boris; Gobert, Sylvie ULg

Poster (2012, May 31)

Although biofouling on Posidonia oceanica (L.) Delile is thought to be driven by the variability of environmental parameters and phenology of the plant, effect of these parameters on sessile animal ... [more ▼]

Although biofouling on Posidonia oceanica (L.) Delile is thought to be driven by the variability of environmental parameters and phenology of the plant, effect of these parameters on sessile animal colonization is still poorly understood. This study aims to document the seasonality and the bathymetric variability of epiphytic Bryozoa diversity and abundance on this seagrass Posidonia shoots were collected in the Revellata bay (Corsica, Mediterranean) in five seasons from 7 to 30 m depth. Colony densities may reach more than 87000 colonies. m-2 at 10 m depth in spring; this probably implies an important contribution of Bryozoa larvae to spring plankton where P. oceanica meadows are present. The Bryozoa specific distribution and abundance appeared to be determined by the seasonality of both the environmental parameters and the plant phenology. However, depth and associated environmental gradients played a structuring role. Based on our data and on the literature, we propose a classification of epiphytic Bryozoa in four categories from hyper-epiphytic specialist to accidental epiphytes and underline the necessity to protect seagrass systems on their full depth range to maximize biodiversity conservation. [less ▲]

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See detailEnvironmental product declarations of mineral paving, a tool for sustainable product choices
Belboom, Sandra ULg; Renzoni, Roberto ULg; Tourneur, Francis ULg et al

Poster (2012, May 30)

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental ... [more ▼]

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental product declarations to strengthen existing databases and to get similar information for their Asian counterparts. Indeed, competition with China for bluestone products and with India for sandstone pavement is very important due to very competitive prices despite their foreign origin and possibly higher induced environmental impacts. Environmental product declarations of Belgian bluestone and sandstone products were conducted in accordance with the ISO standards and following the stand-ard NF P 01-010. CML 2001 method was used to obtain environmental impacts for ten categories as climate change, acidification, abiotic resources depletion, etc. Boundaries of the Belgian systems are the same and the life cycle assessment comprises all steps from the extraction of minerals to the implementation on site. Use and end of life steps were neglected due to the low required maintenance and the inert nature of the paving. For Asian products, the analysis is reduced to the transportation of the functional unit, mainly due to the lack of reliable data. This work highlights the negative effect of long distance transportation of heavy and non-energetic products. Indeed, the environmental impacts of the sole transport of Asian products are at least as important as those obtained for the whole life cycle of Belgian products, whatever the category taken into account (climate change, acidification, air pollution, etc.). CML 2001 methodology was successfully applied to these five studies about three Belgian products and two abroad transportation steps. Comparison of the 5 corresponding environmental product declarations permits to highlight the importance of the transport on environment and to promote, supposing equal performance, local prod-ucts in a more environmental-friendly point of view. [less ▲]

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See detailRhythms in Neuromorphic Reinforcement Learning
Dethier, Julie ULg; Ernst, Damien; Sepulchre, Rodolphe

Poster (2012, May 28)

Living organisms are able to successfully perform challenging tasks such as perception, classification, association, and control. In hope for similar successes in artificial systems, neuromorphic ... [more ▼]

Living organisms are able to successfully perform challenging tasks such as perception, classification, association, and control. In hope for similar successes in artificial systems, neuromorphic engineering uses neurophysiological models of information processing in biological systems to emulate their functions. Our focus lies in the basal ganglia (BG) and specifically on their involvement in action selection and reinforcement learning (RL). The BG are a group of interconnected subcortical nuclei that participate in cortical-­‐ and sub-­‐cortical loops for limbic, associative, and sensorimotor functions. These loops are topographically organized in relatively discrete channels that loop back, via appropriate thalamic relays, to the same area of cortex they originated from. The action selection mechanism comes directly from the BG architecture: the parallel channels compete for behavioral resources, conveying phasic excitatory signals–bids for selection–to the input nuclei. Through comparison of input magnitudes, the tonic inhibitory output is withdrawn from selected channels and maintained or increased on non-­‐selected channels, releasing or preventing action, respectively. This action selection model can be exploited in Cognitive Pattern Generators, analogue to the motor system's Central Pattern Generators, rhythm generators that operate to organize cognition. The BG play also a critical role in reward and RL circuits. Phasic firing in midbrain dopaminergic neurons complies with the reward prediction error signal of contemporary learning theories. This mechanism could explain cognitive functions, e.g. conditioning memory, and dysfunctions, e.g. Parkinson’s and schizophrenia. Modeling rhythms at the neurocellular level could introduce the rhythmic component required at the network level for both action selection and RL. The first step in this project is the modeling of the BG and their parallel processing loops with this rhythmic component, a subject of ongoing research. [less ▲]

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See detailPerformances de croissance et aptitudes bouchères du Poulet Kabyle
Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg; Ait Kaki, Asma ULg et al

Poster (2012, May 27)

Face à la hausse rapide de la consommation mondiale de viande de volaille et afin de s’inscrire dans la perspective d’un développement durable, l’aviculture a connu et connaîtra encore de profondes ... [more ▼]

Face à la hausse rapide de la consommation mondiale de viande de volaille et afin de s’inscrire dans la perspective d’un développement durable, l’aviculture a connu et connaîtra encore de profondes mutations. L’expansion rapide de l’élevage intensif de souches hybrides, génétiquement uniformes, se réalise au détriment des races locales de poules. Ces dernières constituent pourtant un outil central du développement socio-économique rural dans diverses régions du monde. Le but de cette étude est d’étudier les performances de croissance du Poulet Kabyle en production intensive. L’expérimentation s’est déroulée dans la Région de Basse Kabylie et a consisté en deux essais consécutifs de mars à juin 2010 (n=150 poussins) et d’août à novembre 2010 (n=155 poussins). À l’éclosion, le poids moyen des poussins de la première répétition (mâles : 41,29 g, femelles : 36,26 g) n’était pas significativement différent (p>0,05) de celui de la deuxième répétition (mâles : 37,30 g, femelles : 31,94 g). A la fin de l’expérimentation, les poulets de la première répétition présentaient un poids significativement (p<0,05) supérieur à ceux de la deuxième répétition (mâles : 1978,93 g, femelles : 1448,57 g vs. mâles : 1803,30 g, femelles : 1234,48 g). L'étude des différents paramètres de la courbe de croissance (modèle de Gompertz) a révélé des valeurs différentes selon le sexe et la répétition. Aucune différence significative (p>0,05) n’a été observée entre les mortalités, les poids moyens à l’abattage, les rendements, les pH des muscles, des animaux des deux répétitions. Le poids moyen à l’abattage des mâles et leur rendement a été significativement (p<0,05) supérieur à celui des femelles. Les pH des muscles se stabilisent à une valeur appelée pH ultime variant de 5,68 à 5,81. [less ▲]

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See detailComparaison de la qualité des œufs de la race de poule locale Kabyle et de son croisement avec la souche industrielle Isa-Brown
Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg; Ait Kaki, Asma ULg et al

Poster (2012, May 27)

La qualité de l’œuf de poule et les performances de ponte peuvent varier en fonction de la race. Dans les systèmes d’élevage extensifs à semi-intensifs des pays en développement, le croisement entre une ... [more ▼]

La qualité de l’œuf de poule et les performances de ponte peuvent varier en fonction de la race. Dans les systèmes d’élevage extensifs à semi-intensifs des pays en développement, le croisement entre une race de poule locale et une souche industrielle pourrait constituer une opportunité, délivrant un produit commercial alliant rusticité et performances zootechniques. Dans un contexte mondial d’érosion de la biodiversité avicole, ce type de croisement apporte une motivation économique à la conservation de la lignée parentale locale. Le but de cette étude est de comparer le taux de ponte et la qualité des œufs, en termes de composition, de la race de poule locale Kabyle (KAB) et de son croisement (ISAKAB) avec la souche industrielle Isa-Brown (ISA). Les analyses sur la qualité des œufs ont été réalisées durant trois périodes (semaines 35 à 36, 50 à 51 et 65 à 66). L’âge d’entrée en ponte était significativement supérieur pour la poule Kabyle par rapport au croisement ISAKAB (165,96 jours vs. 140,76 ; p<0,0001). Le nombre d’œufs pondus annuellement par la poule ISAKAB est significativement supérieur (194,20 vs. 173,44 ; p<0,05) Le rapport jaune/blanc était identique pour les deux races comparées, avec une moyenne globale de 0,56. Le poids de l’œuf était supérieur chez la poule ISAKAB (53,55 vs. 48,86 ; p<0,0001). Dès lors, les performances de ponte et la qualité des œufs de la poule Kabyle ont été améliorées par le croisement avec la souche Isa-Brown. [less ▲]

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See detailComparaison de la qualité des œufs de deux races de poules Vietnamiennes (Ri et Mia)
Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg; Do Duc, Luc ULg et al

Poster (2012, May 27)

Dans le contexte de valorisation de la biodiversité avicole, ce travail se propose de poser les bases d’une réhabilitation des poules locales Vietnamiennes, particulièrement adaptées aux conditions ... [more ▼]

Dans le contexte de valorisation de la biodiversité avicole, ce travail se propose de poser les bases d’une réhabilitation des poules locales Vietnamiennes, particulièrement adaptées aux conditions d’élevage peu intensives de ce pays. La grande importance socioéconomique et culturelle de ces races pourrait être renforcée et exploitée à des fins de développement rural par la promotion de filières de qualités différenciées. De telles évolutions nécessitent de caractériser le potentiel de production de ces races sur le plan qualitatif. Cette étude a pour objectif l’étude de la qualité des œufs des races de poules vietnamiennes Ri et Mia. La première est la poule la plus répandue au Vietnam et la deuxième est une race menacée d’extinction. Dix neuf caractères de qualité externe et interne de 90 œufs de la poule Ri et 60 œufs de la poule Mia ont été mesurés à 40 et à 60 semaines. Le poids entier moyen des œufs de la Mia (44,70g) était significativement (p<0,001) supérieur à celui de la poule Ri (41,68g). Le rapport jaune/blanc n’était pas significativement (p>0,05) différent à l’âge de 40 semaines (Ri : 0,55 ; Mia : 0,58). À l’âge de 60 semaines, ce rapport devient significativement supérieur pour les œufs Mia alors que celui des œufs Ri (0,64 vs. 0,57 ; p<0,05). Aucune différence significative (p>0,05) n’a été enregistrée entre les deux races pour les paramètres de fraîcheur des œufs (unités d’Haugh et pH des blancs et des jaunes) et de résistance des coquilles (force maximale de rupture). Malgré le faible effectif de cette étude, des différences significatives entre les performances de production ont été observées entre ces deux races phénotypiquement et génotypiquement proches. [less ▲]

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See detailHomogenizing clinical training through ‘à la carte’ self-directed learning
Maillart, Christelle ULg; Grevesse, Pascale; Wiot, Nathalie

Poster (2012, May 25)

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See detailPHARMACOMODULATIONS DU WAY-100635 : DE NOUVELLES PISTES DANS LA CONCEPTION D’ANTAGONISTES SÉLECTIFS DES RÉCEPTEURS 5-HT1A
Dilly, Sébastien ULg; Mangin, Floriane; Joly, Benoît ULg et al

Poster (2012, May 24)

Le composé WAY-100635 est un outil pharmacologique abondamment utilisé dans l’exploration des récepteurs sérotoninergiques 5-HT1A. Dès lors, cette molécule de référence devrait présenter une sélectivité ... [more ▼]

Le composé WAY-100635 est un outil pharmacologique abondamment utilisé dans l’exploration des récepteurs sérotoninergiques 5-HT1A. Dès lors, cette molécule de référence devrait présenter une sélectivité importante pour sa cible. Cependant, des travaux récents ont démontré que, à côté de son activité antagoniste des récepteurs 5-HT1A, le WAY-100635 possédait également une affinité et activité conséquentes vis-à-vis des récepteurs dopaminergiques D4, ce qui pourrait limiter son utilisation comme outil pharmacologique. Dans ce contexte, nous avons entrepris diverses modulations structurales de cette molécule de manière à augmenter sa sélectivité vis-à-vis des récepteurs 5-HT1A. Cette sélectivité a été augmentée de manière significative lors du remplacement de la chaîne latérale basique par un groupement 4-phénylpipérazine ou 4-phényl-1,2,3,6-tétrahydropyridine. Une évaluation biologique plus approfondie des deux composés comprenant un profil d’affinité élargi à d’autres récepteurs a confirmé leur sélectivité vis-à-vis des récepteurs 5-HT1A. De plus, des expériences électrophysiologiques sur tranches de cerveau. [less ▲]

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See detailEtude de la flore bactérienne de steacks tartares prélevés en boucherie, sandwicherie et restaurant par analyse métagénomique ciblée sur l’ADN ribosomial 16S.
Taminiau, Bernard ULg; Delhalle, Laurent ULg; Nezer, Carine et al

Poster (2012, May 24)

Etude de la flore bactérienne de steacks tartares prélevés en boucheries, sandwicheries et restaurants par analyse métagénomique ciblée sur l’ADN ribosomial 16S. Taminiau B.1, Delhalle L 2, Nezer C.2 ... [more ▼]

Etude de la flore bactérienne de steacks tartares prélevés en boucheries, sandwicheries et restaurants par analyse métagénomique ciblée sur l’ADN ribosomial 16S. Taminiau B.1, Delhalle L 2, Nezer C.2, Daube G 1 1 Université de Liège, Faculté de Médecine Vétérinaire, Département des Sciences des Denrées Alimentaires ; Sart Tilman B43 Bis, 4000 Liège, Belgique ; T+32 (0)4 366 40 29 / F+32 (0)4 366 40 44 2 Quality Partner sa, 62 Rue Hayeneux, 4040 Herstal, Belgique ; T+32 (0)4 240 75 00 / F+32 (0)4 240 75 10 Bernard.taminiau@ulg.ac.be Le steak tartare est une préparation à base de viande hachée de boeuf crue assaisonnée et souvent additionnée de condiments. Cette préparation est souvent accompagnée de frites ou étalée dans un sandwich. L’utilisation de viande crue et la composition de cet aliment rend cette préparation très sensible à l’altération d’origine bactérienne. Une meilleure compréhension de la flore bactérienne composant ce produit est indispensable pour contrôler et comprendre les phénomènes d'altération. L'analyse métagénomique ciblée a permis de caractériser les populations bactériennes de plusieurs échantillons de steak tartare achetés dans deux boucheries, deux sandwicheries et deux restaurants et analysés le jour-même. Une analyse classique microbiologique a été réalisée en parallèle. L'analyse métagénomique a été ciblée sur deux régions différentes de l'ADNr 16S bactérien (V&-V3 et V5-V6), afin de comparer l'efficacité d'identification des bactéries présentes. L’analyse métagénomique a permis de collecter un total de 60.500 séquences pour les 6 échantillons analysés par les deux approches et 356 espèces bactériennes différentes ont pu être identifiées via la région V1-V3. Lactobacillus algidus est la principale espèce présente (52% des séquences totales analysées), suivie par Pseudomonas sp. (8,43%) et Photobacterium phosphoreum (7,92%). L'analyse des résultats montre des différences remarquables entre les trois sources commerciales de steak tartare. Les échantillons provenant des deux boucheries et d’un restaurant étaient principalement composés de populations de Lactobacillus et, dans une moindre mesure, de contaminants environnementaux, comme Xanthomonas campestris. Les échantillons provenant de l'un des deux restaurants étaient fortement contaminés par des Leuconostocaceae comme Leuconostoc carnosum ou Weissella sp., ou avec des gamma-protéobactéries comme Pseudomonas sp. ou Psychrobacter sp. Ces derniers échantillons présentaient aussi des signes d’altérations (mauvaise odeur, aspect) qui peuvent ainsi être mis en relation avec la nature et le niveau des populations bactériennes identifiées. Les échantillons provenant des sandwicheries et probablement issues de filières de production industrielles étaient faiblement contaminés mais avec une grande variabilité dans les flores identifiées. Beaucoup d’entre elles ne sont pas classiquement décrites dans les viandes crues et doivent provenir des autres ingrédients. La combinaison du séquençage haut débit couplé à la bioinformatique est désormais un outil puissant pour l’analyse microbiologique des denrées alimentaires. Son application peut être étendue à pratiquement tous les aliments. Enfin, cette technologie ouvre de nouvelles perspectives aux industries agro alimentaires pour améliorer leurs procédés de fabrication, leurs recettes et leurs méthodes de conservation. [less ▲]

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See detailValidation d’une activité de psychomotricité adaptée aux grands prématurés
Jidovtseff, Boris ULg; Vandermeulen, Mary; Dutilleux, Benjamine ULg et al

Poster (2012, May 23)

Pendant la petite enfance, les grands prématurés restent fragiles. Une étude récente (de Kieviet et al, 2009) met en évidence un retard psychomoteur de cette population par rapport à la normale. A partir ... [more ▼]

Pendant la petite enfance, les grands prématurés restent fragiles. Une étude récente (de Kieviet et al, 2009) met en évidence un retard psychomoteur de cette population par rapport à la normale. A partir de 3 ans, de nombreuses activités existent pour stimuler leur développement moteur mais avant cet âge, rien n’est organisé. Nous avons donc décidé de mettre sur pied une activité de psychomotricité adaptée à cette population, entre 1,5 et 3 ans. L’objectif de cette étude consistait à valider cette activité de développement originale. Appliquant les principes des recherches-action, nous avons structuré notre démarche en quatre phases : (1) la planification durant laquelle nous avons mené une réflexion sur l’organisation et le contenu de l’activité ; (2) l’intervention au cours de laquelle fut expérimentée l’activité et fut collectée une série d’informations ; (3) l’analyse des données et ; (4) l’aménagement d’un nouveau modèle tenant compte des étapes précédentes. La validation menée lors de l’intervention repose sur la triangulation des données : interview et questionnaires proposés aux parents, questionnaire adressé aux moniteurs et interviews semi-structurées réalisées auprès de 10 experts de la psychomotricité et/ou des prématurés (pédiatres, kinésithérapeutes, logopèdes, psychologues, psychomotriciens). Une analyse de contenu a été réalisée afin de dégager les éléments de sens qui ont été compilés. Les différents acteurs s’accordent sur la majorité des éléments proposés dans les activités (contenu, matériel, espaces, diversité) et sur l’organisation (structuration, jeux libre, binôme kinésithérapeute-éducateur sportif). Des ajustements paraissent nécessaires au niveau de la phase d’accueil et du rituel de fin de séance. La présence des parents durant l’activité fait débat. Le projet a été initialement bien pensé et la majorité du concept a été validée par les experts. De légères adaptations ont été programmées. Cette étude renforce la crédibilité de l’initiative dont l’intérêt a été chaleureusement salué par les parents. [less ▲]

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See detailColoring of the infinite grid
Vandomme, Elise ULg; Gravier, Sylvain

Poster (2012, May 23)

We present a method that links (r,a,b)-codes in the infinite grid and particular colorings of weighted cycles, called constant 2-labellings.

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See detailImpact d'un cycle d'activités physiques en milieu professionnel sur le style de vie et le stress
Robyns de Schneidauer, Jérôme ULg; Etienne, Anne-Marie ULg; Pouillon, Mathieu et al

Poster (2012, May 23)

En termes de santé, la prévention du stress psychologique sur le lieu de travail devient un enjeu important. Outre ses bénéfices sur la santé générale, l’activité physique est considérée comme une ... [more ▼]

En termes de santé, la prévention du stress psychologique sur le lieu de travail devient un enjeu important. Outre ses bénéfices sur la santé générale, l’activité physique est considérée comme une stratégie de coping face au stress [Steptoe et al., 1989]. Afin de répondre au manque de temps souvent mis en avant par les employés, nous avons décidé de tester un programme d’activités physiques en entreprise. Le défi consistait à élaborer un programme pouvant être réalisé n’importe où, sans équipement spécifique et sans engendrer une sudation importante des participants. Cette étude avait pour but d’identifier l’impact de ce programme sur le stress psychologique (lié au travail) et sur les niveaux d’activité physique. Ce programme (2 x 45 min/semaines pendant 10 semaines) alliait exercices gymniques et jeux de team building. Des salariées (n=29) de l’ULg ont participé à ce programme quasi-expérimental de type « Switching Replication Design ». Elles ont répondu à trois reprises à un questionnaire (pré-test, post-test Groupe 1 et post-test Groupe 2) et à une interview individuelle (post-expérimentation). La méthode d’évaluation du stress s’est appuyée sur la Job Stress Scale [Spielberger et al., 1970], la Perceived Stress Scale [Cohen et al., 1983] et la Mesure de Stress Psychologique [Lemyre et al., 1990]. Nous avons constaté une diminution significative du stress lié au travail (-9.2%) et du stress général (-12,3%) et une augmentation du niveau d’activité physique. Le G1 maintient les changements pendant 3 mois après l’intervention. Après le programme, 6 sujets ont repris une activité physique régulière. D’autres effets ont été observés : une meilleure perception de la santé et une diminution des douleurs physiques perçues. Ce programme souligne l’importance de la détente au travail, de l’ambiance positive et de la relaxation dans les exercices proposés afin de diminuer le niveau de stress via l’activité physique. [less ▲]

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See detailA Promising Perspective for Pathologies Diagnosis by MALDI In-Source Decay Imaging with a FTMS System.
Calligaris, David ULg; Debois, Delphine ULg; Turtoi, Andrei ULg et al

Poster (2012, May 23)

Introduction MALDI imaging mass spectrometry has proven to be effective for the discovery and the monitoring of disease-related proteins. With this technique a molecular diagnosis could be done directly ... [more ▼]

Introduction MALDI imaging mass spectrometry has proven to be effective for the discovery and the monitoring of disease-related proteins. With this technique a molecular diagnosis could be done directly on tissue sections in the environment of the diseased area. The use of in-source decay (ISD), that does allow fast and reliable sequences assignments of proteins termini, is a crucial tool for the identification of known biomarkers during MALDI imaging experiments. Combined with ultra-high mass resolution and high mass measurement accuracy of Fourier transform ion-cyclotron (FTICR) mass spectrometry, it is possible to unambiguously assign sequences of proteins present in tissue slices. In this study, we have shown that FTICR mass spectrometry could be a powerful tool to diagnose pathologies by MALDI-ISD imaging. Methods All measurements were carried out on a SolariX FTMS (9.4 tesla) equipped with a Dual Source including smartbeamTMII laser which includes a robust solid state 1 kHz laser with advanced optics for molecular imaging (Bruker Daltonics). Lysozyme (14.3-kDa) or Human Serum Albumin (66.3-kDa) solution (1 mg/ml in 0.1 % TFA) was mixed with 1,5-diaminonaphthalene (DAN) and analyzed by MALDI-ISD and MALDI-ISD imaging. Mouse brain and rabbit eye tissue slices were washed (fixed) to obtain optimal sensitivity and high-quality ion. Before DAN application with an ImagePrep (Bruker Daltonics) and MALDI-ISD imaging analyzes, spots of myelin and crystalline were deposited near mouse brain or rabbit eye tissues, respectively. Results were interpreted using BioToolsTM 3.2 in combination with MascotTM (Matrix Science) for ISD spectra and FlexImagingTM 2.1 for MALDI-ISD imaging experiments. α Preliminary data The studies were carried out by MALDI-ISD and MALDI-ISD imaging analyses to evidence the interest on FTICR mass spectrometer for proteins identification in the field of biomarkers characterization. It is demonstrated that protein ISD leads to the same pattern of fragmentation observed during MALDI-TOF analyzes. Fragmentation generates cn- and zn-series ions of lysozyme and HSA in presence of DAN. Supplementary an-, bn-, xn- and yn-series ions can also be observed. The internal calibration of all the data provides a mass accuracy neighboring 2.5 ppm over the m/z range of interest (300-2500 Da) and a mass resolution of 70000 at m/z 400 Da. It allows the assignment of ISD fragments of proteins, in the low mass range (m/z between 300 and 900), whether from pure solutions or included in tissue slices. Moreover, spots of pure proteins solution (myelin or crystalline) near tissue slices allows to unambiguously validate the proteins identification during MALDI ISD imaging experiments. Novel aspect This study evidences the main input of FTICR mass spectrometer for pathologies diagnosis based on biomarkers localization and identification by MALDI-ISD imaging. [less ▲]

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See detailBanana macropropagation: an alternative way of producing seedlings for the farmers in Burundi
Nintije, Pierre ULg; De Clerck, Caroline ULg; Bigirimana, Joseph et al

Poster (2012, May 22)

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See detailUne nouvelle approche de la microbiologie alimentaire avec l’analyse métagénomique : un exemple avec une analyse de filets de poisson
Delhalle, Laurent ULg; Taminiau, Bernard ULg; Nezer, Carine et al

Poster (2012, May 22)

L’analyse métagénomique est un outil puissant pour étudier la flore bactérienne d’échantillons issus de divers environnements. Cette technologie commence à être appliquée à des aliments mais seulement sur ... [more ▼]

L’analyse métagénomique est un outil puissant pour étudier la flore bactérienne d’échantillons issus de divers environnements. Cette technologie commence à être appliquée à des aliments mais seulement sur l’étude de produits asiatiques fermentés. Ce travail décrit l’application de cette technologie pour étudier la population bactérienne de deux types de filets de poissons : un issu d’un poisson d’eau douce chaude (pangasius) et un de poisson d’eau de mer (églefin). Les échantillons ont été directement analysés le jour de la réception. D’autres échantillons ont été analysés à la fin de leur durée de vie après stockage à 4°C (1/3 de la durée de vie) et 8°C (2/3 de la durée de vie). Ces échantillons ont été conditionnés en barquette de polystyrène et film étirable sous air atmosphérique et en barquette et film PP-EVOH sous atmosphère modifiée (50% N2 / 50% CO2). Des analyses microbiologiques classiques et métagénomiques ciblant l’ADNr 16S ont été réalisés sur tous les échantillons. L’évolution des populations microbiennes des filets de poissons conservés sous différents types de conditionnement et de température a été étudiée. Quarante espèces bactériennes différentes ont été identifiées pour les deux types de poissons. Les bactéries Gram négatives sont majoritaires que ce soit au début ou à la fin de la durée de vie des produits et quel que soit le type de conditionnement. Au début de la conservation, les bactéries Gram négatives présentes sont essentiellement des Moraxellaceae (Acinetobacter spp, Psychrobacter sp.), Pseudomonadaceae (Pseudomonas spp), et Shewanella spp et les bactéries Gram positives sont des Lactobacillaceae (Carnobacterium spp), Brochothrix thermosphacta et Planococcus donghaensis (seulement pour le pangasius). Suivant le type de conditionnement et le type de poisson, des variations importantes de la flore initiale ont été observées. La croissance de certaines espèces Gram négatives pourrait être un indicateur d’altération. Par conséquent, l’analyse métagénomique pourrait être un outil supplémentaire pour fixer adéquatement la date limite de consommation. Pour le pangasius, Planococcus donghaensis est présent uniquement avant le conditionnement et sa présence pourrait être un indicateur de la fraîcheur du poisson. Cette étude a permis d’appliquer l’analyse métagénomique pour identifier et mesurer les proportions relatives des espèces bactériennes dans les filets de poissons au cours du temps. [less ▲]

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See detailPhenology of the invasive coccinellid Harmonia axyridis Pallas and other aphidophages in crops
Vandereycken, Axel ULg; Durieux, Delphine ULg; Joie, Emilie ULg et al

Poster (2012, May 22)

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent to control aphids populations, is now frequently considered as an ... [more ▼]

The multicoloured Asian ladybird Harmonia axyridis Pallas (Coleoptera: Coccinellidae), previously introduced as a biological control agent to control aphids populations, is now frequently considered as an intraguild predator, consuming other aphids natural enemies. The interactions between this exotic ladybird and other aphidophagous species present in Belgian agro-ecosystems are mainly asymmetric in support of H. axyridis. An aphidophages sampling has been performed between 2009 and 2011 in four agrosystems such as broad bean, wheat, corn and potato. The sampling method consisted in the counting of aphids and all developmental stages of aphidophages present in quadrats of 1m² from April to September. Harmonia axyridis, the invasive coccinellid, was mainly observed in broad bean (21.84 ± 6.30 individuals/100m²) and corn (70.83±6.60 individuals/100m²) with other aphidophages such as Episyrphus balteatus (De Geer), Chrysoperla carnea sensus lato (Stephens), Coccinella septempunctata (Linné) and Propylea quatuordecimpunctata (Linné). In corn, our field data showed that immature stages and adults of H. axyridis were found throughout the summer. Adults were observed from mid-June to the beginning of September with two peaks, in the late June and in the beginning of August. The life history of larvae starts in late-June to the beginning of Augustus with only one peak (347.91 ± 59.99 individuals /100m²) in the beginning of July. The peak of H. axyridis arrives when no extraguild preys are present. At this moment, pupae of E. balteatus and C. septempunctata are the main food available to ensure the development of H. axyridis so that native aphidophages could be intraguild prey for H. axyridis. In the four crops, reproduction of H. axyridis starts after those of other aphidophages and so it does not benefit of available prey such as aphid: in corn and broad bean, C. septempunctata reproduce the first, in wheat it is E. balteatus and in potato it is C. carnea. That could be explained by several reasons: (1) H. axyridis reproduces firstly in arboreal habitats and after that comes in agrosystems, (2) the delay between aphidophage reproductions allows a reduction of interactions with other larvae during spring and therefore decrease mortality levels and (3) H. axyridis is able to use pollen as food substitute when no aphids are available. [less ▲]

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See detailL’extraordinaire potentiel de l’approche métagénomique en microbiologie des aliments: analyse du microbiote de fromages au lait cru et pasteurisé
Delhalle, Laurent ULg; Nezer, Carine; Darcis, Amélie et al

Poster (2012, May 22)

Parmi les techniques culture indépendante, le développement de l’ultra-séquençage a permis de positionner l’analyse métagénomique comme étant la meilleure alternative pour l’étude de microbiotes complexes ... [more ▼]

Parmi les techniques culture indépendante, le développement de l’ultra-séquençage a permis de positionner l’analyse métagénomique comme étant la meilleure alternative pour l’étude de microbiotes complexes. Durant ces trois dernières années, les études métagénomiques ont été consacrées essentiellement à l’analyse d’échantillons environnementaux. Ce travail décrit l’application de cette technique à l’étude des populations bactériennes de quatre types de fromages à pâte molle. Parmi ceux-ci, trois d’entre eux sont des fromages belges typiques à croute lavée (deux sont fabriqués avec du lait cru et le troisième avec du lait pasteurisé). Le quatrième est un fromage français crémeux à base de lait cru. Des analyses microbiologiques classiques et métagénomiques ciblant l’ADNr 16S ont été réalisées dans le cœur et sur la croute des quatre fromages, donnant un total de 8 échantillons. Au total, 48 genres et 163 espèces bactériennes ont été identifiées pour tous les échantillons. Comme attendu, Lactoccocus lactis subsp lactis et/ou cremoris sont les espèces les plus représentées dans le cœur des quatre fromages. Concernant la croute des fromages, les espèces bactériennes les plus abondantes sont Psychrobacter glacinola, Staphylococcus equorum, Corynebacterium casei et Marinilactibacillus psychrotolerans. A noter la présence de Brevibacterium spp et Psychroflexus spp qui permettent d’obtenir la couleur orangée de la croute. Toutes ces espèces sont présentes en différentes proportions suivant l’origine et le processus de fabrication et sont connues pour leurs propriétés technologiques et/ou organoleptiques. Les deux fromages belges au lait cru sont composés de beaucoup d’espèces bactériennes différentes. Tandis que le fromage au lait pasteurisé contient moins d’espèces, principalement Lactococcus lactis (97,6%) dans le cœur. Un résultat inattendu concerne la faible diversité bactérienne du fromage français crémeux à base de lait cru. Seulement deux espèces étaient majoritairement présentes : Lactoccocus lactis subsp cremoris et Leuconostoc citreum avec respectivement 94,9% et 4,9% dans le cœur et 93,8% et 5% dans la croute). Comparé avec les résultats des autres fromages à base de lait cru, ce résultat est particulièrement surprenant. Le microbiote des fromages joue un rôle central sur le processus de fabrication, les qualités organoleptiques et la durée de vie commerciale des produits. L’analyse métagénomique est devenu un outil puissant, rapide et abordable pour identifier, comprendre et maitriser les flores impliquées [less ▲]

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See detailComment diminuer la quantité de platine dans les piles à combustible ?
Laurent-Brocq, M.; Caldarella, Giuseppe ULg; Job, Nathalie ULg et al

Poster (2012, May 20)

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See detailDrawn in by the unpredictable: reward uncertainty broadens the spotlight of incentive salience attribution
Robinson, Mike J.F.; Fischer, Adam M.; Anselme, Patrick ULg et al

Poster (2012, May 19)

The motivational value assigned to cues (CSs) associated with reward (UCS) is known as incentive salience, and is determined through the synergy of previous learning of the CS-UCS association (the sum of ... [more ▼]

The motivational value assigned to cues (CSs) associated with reward (UCS) is known as incentive salience, and is determined through the synergy of previous learning of the CS-UCS association (the sum of experiences an individual has with that cue-reward combination) and the mesolimbic state of the individual at the time of cue re-encounter. Typically, the amount of incentive salience attributed to a cue is believed to increase with the relative reliability that the cue predicts reward, where cues that consistently predict reward become powerful motivational magnets, eliciting approach and even consummatory behaviors (similar to those produced by the reward itself). In contrast, cues that predict reward with a lesser degree of certainty should theoretically be less attractive, and accrue lower levels of incentive salience. However, in some cases, cues that predict reward with maximal levels of uncertainty, such as in gambling, may generate higher levels of incentive salience attribution and become very attractive. In order to examine the impact of uncertainty, we used a Pavlovian conditioned approach task (autoshaping), where a bright noisy lever cue precedes delivery of a sucrose reward pellet. We have previously shown that a cue that predicts a reward only half the time (probability = 50%), but where the value of that reward can vary (1, 2 or 3 sucrose pellets), attracts more incentive value than a cue that systematically (probability = 100%) predicts a single sucrose reward pellet. Here we examined whether the increased incentive value attributed to uncertain cues was equally distributed across cues that were proximal (5 cm) or distal (20 cm) to the site of reward (magazine). Our results confirm that incentive value is greater for uncertain cues, and show that it is equally distributed across proximal and distal cues. In contrast, when the CS cue predicts the UCS reward with absolute certainty, incentive value is preferentially given to proximal cues, with distal cues being almost ignored. This suggests that reward uncertainty not only attributes more incentive value to cues, but that it may also act by recruiting a broader range of cues. However, since the learnt predictive value of the cue is low, this increase in incentive salience may be generated through greater mesolimbic activity driven by anticipation and/or stress of an unpredictable reward. In conclusion, reward uncertainty may transform a broad array of cues into powerful motivational magnets, which in turn could help explain what makes gambling so attractive. [less ▲]

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See detailDevelopment of mini scale-down platform based on the response of GFP microbial biosensors
Brognaux, Alison ULg; Neubauer, Peter; Twizere, Jean-Claude ULg et al

Poster (2012, May 18)

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

The basic principle adopted in our studies is to use substrate limitation responsive biosensors in order to detect spatial glucose heterogeneities inside industrial bioreactors (whole-cell biosensor). Indeed, such heterogeneities cause a lowering of the biomass yield and an increase of by-products concentration. In our previous works, green fluorescent protein reporters have been used as biosensors of the heterogeneities generated in a two compartment scale-down reactor. As there is a huge variety of available whole cell biosensor to characterize the impact of such heterogeneities at the biological level, there is a need for high-throughput cultivation tools in order to investigate the usefulness of a given microbial biosensor among a library comprising several thousands of clones. This work is based on this statement and aims to investigate the potentialities of a mini scale-down platform. Four green fluorescent protein (GFP) transcriptional reporters have been chosen in Escherichia coli: rpoS::gfp, uspA::gfp, csiE::gfp and yciG::gfp. The promoters rpoS and uspA are induced in response to a variety of stresses whereas the two other promoters, csiE and yciG, are supposed to be more specific in front of a glucose limitation. First, the response of these biosensors has been assessed in chemostat reactors. These kinds of experiments allow easier interpretation of responses of stress gene related to a glucose limitation since the extracellular conditions are constants and cells are renewed. Biosensors carrying the csiE and yciG promoters have exhibited an induction in function of the glucose limitation. Secondly, a scale-down platform has been tested with the same biosensors and two kinds of glucose addition mode. This scale-down platform involves high-throughput cultivation tools, i.e. in our case shake flask, equipped with non-invasive optical sensors for the monitoring of the dissolved oxygen profile in front of the glucose addition mode. The first system is based on a commercial package (Enbase) based on the enzymatic release of glucose in the medium. The Enbase system allows the generation of a very smooth glucose profile without any perturbations. For comparison purpose, we have also used an intermittent feeding that induces strong fluctuation at the level of the glucose and the dissolved oxygen concentration. The intermittent addition of glucose induces a slow down at the level of the GFP synthesis, suggesting that temporal accumulation of glucose inhibits the activity of the yciG and csiE promoters. In conclusion, the scale-down platform is able to reproduce the same kind of glucose fluctuations that encounters the cells in large-scale processes but not allows studying the impact of high-cell density culture on gene expression. [less ▲]

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See detailPhysico-chimie et minéralogie des argiles de Bana (Ouest, Cameroun)
Mache, Jacques Richard ULg; Fagel, Nathalie ULg; SIGNING, Pierre

Poster (2012, May 15)

Dans le but de contribuer à la valorisation des géoressources, notamment les matériaux argileux du Cameroun, nous avons dans ce travail procédé à la caractérisation minéralogique et physico-chimique des ... [more ▼]

Dans le but de contribuer à la valorisation des géoressources, notamment les matériaux argileux du Cameroun, nous avons dans ce travail procédé à la caractérisation minéralogique et physico-chimique des argiles récoltées dans la région de Bana. Pour cela diverses méthodes et moyens d’identification ont été utilisés, notamment la diffraction des rayons X (DRX), l’analyse chimique, la spectroscopie infrarouge, la microscopie électronique à balayage, l’analyse thermique, l’analyse granulométrique, la détermination des capacités d’échange cationique et la détermination de la surface spécifique. Les résultats de cette étude ont montré que les argiles de Bana sont formées principalement de smectite, kaolinite et talc comme minéraux argileux. Les minéraux non argileux associés sont l’anatase, le quartz, le feldspath, la goethite et l’hématite. Les observations au microscope électronique à balayage sont conformes avec la nature smectique de ces matériaux (Figure 1). Les capacités d’échange cationique (comprises entre 40 et 57 méq/100g) et les surfaces spécifiques (comprises entre 50 et 68 m2) sont également dans les moyennes mesurées pour des argiles smectiques (Morgan et al.,1985; Van Olphen et Fripiat,1979). Le test de saturation au lithium (test de Green Kelly - Lim et Jackson, 1986) a permis d’établir que la montmorillonite était le minéral smectique de ces argiles. Le couplage des analyses chimiques et minéralogiques permet une quantification minéralogique moyenne: 74% de Montmorillonite; 6% de Kaolinite; 8% de talc. Les matériaux de Bana sont riche en smectite et peuvent dont être valorisés dans les domaines tels que l’absorption, l’agriculture ou de l’imperméabilisation des sols. [less ▲]

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See detailCaractérisation des dépôts argileux de Nanga-Eboko (Centre Cameroun):Aptitude dans la production des briques cuites
Nzeukou Nzeugang, Aubin ULg; Medjo Eko, Robert; Fagel, Nathalie ULg et al

Poster (2012, May 14)

Cette étude entre dans le cadre de la valorisation des argiles industrielles du Cameroun avec pour perspective la mise sur pied des unités de production industrielles des matériaux de construction ... [more ▼]

Cette étude entre dans le cadre de la valorisation des argiles industrielles du Cameroun avec pour perspective la mise sur pied des unités de production industrielles des matériaux de construction (Briques et tuiles cuites). Ainsi, dans ce travail, nous avions à estimé à 9-12)x105 m3 la quantité d’argile que regorge la localité Nanga-Eboko (Région du Centre Cameroun). Sur le plan chimique, l’argile contient: ~70% silice, ~ 12% alumine, ~ 7% fer) et sur le plan minéralogique :~ 40-60% kaolinite, ~20-25% quartz et illite ~12% Feldspath et smectite sont présents (9 et 5% resp.). L'observation microscopique et l’IR montrent des formes irrégulières de kaolinite mal cristallisée, caractéristique des argiles d'origine sédimentaire. Les propriétés des briques (800-1100°C) montrent un retrait linéaire élevé (3-11%), un taux d'absorption d'eau faible (17-8%) et des valeurs de compression (11-50 Mpa). Au vu de la plasticité élevée (24%) de ces argiles, de leurs particules fines (<2 µm) >70%, l'ajout de dégraissant (sable ou latérite) est nécessaire pour une bonne optimisation du mélange afin d'avoir un produit fini de qualité pour la construction de bâtiments. [less ▲]

Detailed reference viewed: 129 (15 ULg)
See detailSinduced alternative splcing eventstudy of camptothecin- and cisplatin-
Deward, Adeline; Gabriel, Maude; Delforge, Yves et al

Poster (2012, May 11)

Various genotoxic drugs used in cancer therapy induce alternative splicing or pre-messenger RNA. The nature and the intensity of alternative splicing was compared for Camptothecin, Cisplatin and .

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See detailZoonotic diseases in pet birds – a short review
Boseret, Géraldine ULg; Saegerman, Claude ULg

Poster (2012, May 11)

The term « Pet bird » designates birds housed and breeded for an exclusively ornamental use. This category includes mainly Passeriformes (canaries, finches…) and Psittaciformes (parrots, parakeets…), and ... [more ▼]

The term « Pet bird » designates birds housed and breeded for an exclusively ornamental use. This category includes mainly Passeriformes (canaries, finches…) and Psittaciformes (parrots, parakeets…), and is a not-so-well known vet’s clientship fraction. Many families indeed own their « kitchen canary », which represent a lucrative business for pet shops or local breeders (e.a. via birds fairs and markets). Besides, some birds are bred for their very high value; for example, in the case of canaries, male and female reproductors with recognized genetic potential are presented in international contests for their posture (the Bossu Belge : fig 1a), their colour (red mosaic: fig 1b) and for their song (Harzer: fig 1c) and sold for rising prices. Finally, exotic birds like parrots (ara, cockatoo…), legally or illegaly traded from Asia, are however very popular pets and profusely represented in zoos and parks. Notwithstanding these economic facts, these animals are potential carriers and/or transmitters of zoonotic diseases. Some of them could have an important impact on human health, like ornithosis, salmonellosis or even H5N1 high pathogenic avian influenza. This review, although non exhausive, has as aim to enlighten, by the description of several cases of birds-humans transmission the risks encountered by birds owners, including children, and on another point of view to assess the potential economic consequences. [less ▲]

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See detailMemory testing for the early diagnosis of Alzheimer’s disease: Comparative study
Grotz, Catherine ULg; Adam, Stéphane ULg; Teunisse, Jan-Pieter et al

Poster (2012, May 11)

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See detailA new way of predicting everyday life functioning: Validation of a Computerized Meeting Preparation Task with persons diagnosed with schizophrenia
Laloyaux, Julien ULg; Levaux, Marie-Noëlle ULg; Mourad, Haitham et al

Poster (2012, May 11)

Deficits in everyday life functioning are a core feature of persons diagnosed with schizophrenia. However, functional outcome is usually evaluated with questionnaires and performance-based assessments ... [more ▼]

Deficits in everyday life functioning are a core feature of persons diagnosed with schizophrenia. However, functional outcome is usually evaluated with questionnaires and performance-based assessments, all of which contain a number of limits. We developed a computerized real-life activity task (meeting preparation task) where participants are required to prepare a meeting room. Twenty-one individuals diagnosed with schizophrenia and 21 matched healthy controls completed the task. Patients were also evaluated with a cognitive battery and measures of symptomatology and functional outcome. Results showed that performance on the computerized task significantly differentiated patients and controls for a certain number of variables. These variables, combined into a composite score, were significantly correlated with both cognitive functioning and functional outcome. Moreover, this composite score significantly predicted 39% of functional outcome, whereas a cognitive composite score did not reach significance. In addition, when the meeting task composite score was combined with symptomatology and the cognitive composite score, these measures significantly predicted 70% of functional outcome. These findings suggest that the meeting preparation task provides a valid and significant indication of the level of everyday life functioning in patients with schizophrenia, and may be viewed as a valuable instrument in both an evaluation and remediation context. [less ▲]

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See detailSexual abuse: is regression in borderline functioning a risk factor for acting out within the interfamilial system?
Aubinet, Suzanne; D'Amore, Salvatore ULg; Cancrini, L et al

Poster (2012, May 11)

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See detailComparison of the effect of learning to read in English or in Dutch on the acquisition of the French orthographic code in French-speaking children attending immersion school programs.
Binamé, Florence ULg; Poncelet, Martine ULg; Guyon, Charline

Poster (2012, May 10)

Most of the children attending bilingual immersion school programs in the French Community of Belgium learn to read in the immersion language before learning to read in their native language. This study ... [more ▼]

Most of the children attending bilingual immersion school programs in the French Community of Belgium learn to read in the immersion language before learning to read in their native language. This study aimed to explore the effect of learning to read in a second language having a transparent (Dutch) versus an opaque (English) orthographic code, on the later acquisition of French spelling. Because literacy acquisition depends on the orthographic depth of the code, the hypothesis is that learning to spell in a transparent language such as Dutch would promote the acquisition of the more opaque French spelling, by transferring the phonological recoding process. Contrariwise, the acquisition of French spelling would be less easy if learners were first immersed in very opaque spelling such as English. Participants were 182 third and fourth-graders immersed in Dutch or English, and monolingual French speakers (control group). Their French spelling skills were tested by words and non-words dictation. Results showed that the performance of Dutch immersed children was not significantly inferior to controls, which is not the case for English immersed children. This corroborates the fact that learning to spell in a more transparent orthographic code than French has a subsequent benefit on its acquisition. [less ▲]

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See detailThe influence of verbal descriptions and delay on face identification in children and adults.
Vanootighem, Valentine ULg; Dehon, Hedwige ULg; Brédart, Serge ULg

Poster (2012, May 10)

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in adults, a phenomenon known as the “verbal overshadowing effect (VO)” (Schooler & Englster-Schooler ... [more ▼]

Verbal descriptions of unfamiliar faces have been found to impair later identification of these faces in adults, a phenomenon known as the “verbal overshadowing effect (VO)” (Schooler & Englster-Schooler, 1990). In spite of a large body of literature on the suggestibility of children testimony, only one study has examined whether descriptions also impaired children’s identification abilities in a single group of children (8-9 years old) and no evidence of VO was found (Memon & Rose, 2002). However, the method might not have been appropriate to observe this effect as the description and the control tasks were not completed immediately but after a 24h delay that has sometimes been associated to a release of the VO effect (e.g. Schooler & Englster-Schooler, 1990; Finger & Pezdek, 1999). The aim of this experiment was to examine the influence of verbal descriptions and delay on face identification in several groups of children (7-8, 10-11, 13-14 years old) and adults when assigned either to “No delay”, “Post description delay” or “Post encoding delay” condition. The quality and influence of descriptors across the ages were also examined. [less ▲]

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See detailCrosslinking of star-shape PCLs through Diels-Alder reactions for the preparation of shape memory polymers
Defize, Thomas ULg; Riva, Raphaël ULg; Thomassin, Jean-Michel ULg et al

Poster (2012, May 10)

Poly(ε-caprolactone) (PCL), a semi-crystalline polymer, is one of the most widely studied polymers for the development of shape memory materials when chemically cross-linked. PCL presents several ... [more ▼]

Poly(ε-caprolactone) (PCL), a semi-crystalline polymer, is one of the most widely studied polymers for the development of shape memory materials when chemically cross-linked. PCL presents several advantages such as a melting transition temperature close to human body temperature, a high biocompatibility and is (bio)degradable. So, this polymer is highly relevant for both biomedical devices such as stents or resorbable suture wires and also for degradable packaging. However, after cross-linking, the material can not be reprocessed, preventing any reuse/recycling of the material. One of the purposes of this work is to find a solution to this major drawback, which would then allow, for example, to reshape packaging films after use or to recycle trimmings remaining after fabrication. Amongst current trends in the design of new polymer and composite materials, the use of organic reactions that are able to create and reversibly disrupt chemical bonds upon an external stimulus (temperature, irradiation,…) is currently gaining more and more attention as it can lead to applications in various areas such as remendable materials, drug delivery systems, stimulus-degrading materials or recyclable materials. This contribution aims at reporting a new concept for the preparation of well defined and recyclable PCL based reversibly cross-linked shape memory polymer by the formation of reversible carbon-carbon bonds. Amongst all the reversible links described in the literature, thermally (4+2) reversible cycloadditions present interesting features such as the creation of robust bonds and well defined reversibility conditions. As an example, the application of furan/maleimide adducts as covalent link, which cycloreversion is largely favored in the range of temperature (90-120°C), is widely reported. For this purpose, commercially-available star-shaped PCL precursors have been selected and selectively modified at their chain ends either by a diene (furan, anthracene) or a dienophile (maleimide). Typically, PCL-based shape memory materials have been prepared by mixing a stoichiometric amount of diene-bearing and maleimide-bearing PCLs in a twin-screw mini-extruder at a temperature which favors cycloreversion. The polymer blend is then cured at 65°C (just above PCL melting temperature), with the purpose to increase chains mobility and improve the formation of the adducts. Cross-linked PCLs were obtained, as evidenced by swelling experiments. The shape memory properties of the materials have been studied by cyclic tensile thermomechanical analysis. The influence of the nature of the Diels-Alder moieties on the cross-linking rate and on the shape memory properties has been studied. Reversibility of the network formation in the case of furan, used as diene, has been assessed by rheology and by recycling experiment. [less ▲]

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See detailSynthesis of new biomimetic biodegradable materials for clinical use
Clement, Benoît ULg; Grignard, Bruno ULg; Lecomte, Philippe ULg et al

Poster (2012, May 10)

For recent decades, the most commonly biodegradable polymers used in clinical and therapeutic applications are aliphatic polyesters such as polyglycolide, polylactide, polycaprolactone and their ... [more ▼]

For recent decades, the most commonly biodegradable polymers used in clinical and therapeutic applications are aliphatic polyesters such as polyglycolide, polylactide, polycaprolactone and their copolymers, mainly due to their excellent biocompatibility and biodegradability properties. However, the lack of functional groups on the backbone of polyesters, which could otherwise be used for tuning physicochemical properties and for introducing bioactive units, limits their further biomedical applications. Polymers with repeating phosphoester bonds in the backbone are structurally versatile and biodegradable through hydrolysis and possibly enzymatic digestion of phosphates linkages under physiological conditions. An advantage of polyphosphoesters (PPEs) compared to aliphatic polyesters is the possible functionalization of side chains due to the patenvalency of the phosphorous atom, allowing the introduction of bioactive molecules and extensive modification of the physical and chemical properties of final material. The Ring-Opening Polymerization (ROP) of cyclic esters is a well-established process to provide linear polyesters with predictable molecular weight, narrow polydispersity and well-defined end-groups. Up to now, metallic compounds are particularly used as initiators or polymerization catalysts to synthetize these materials but metallic derivatives are cytotoxic and a lack of residual metal contaminants is strongly required in view of biomedical applications. To tackle these drawbacks, we developed synthetic approaches that are metal-free (i.e., organocatalytic) using organocatalysis based on supramolecular recognition. A variety of organocatalysts such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]undec-5-ene (TBD) and a bicomponent thiourea-tertiary amine catalyst were studied. Each of these catalysts is efficient to produce linear polyphosphoesters (PPEs) from cyclic phosphate monomers (CPMs) but with different sensitivity towards transesterification side reactions. Compared with polymerizations carried out with Sn(Oct)2 as a metal catalyst, the control of polymerization is much better so that it is possible to prepare PPEs with molecular weight close to 70000 g.mol-1 and polydispersity index below 1.10. The chain extension experiments through the use of hydroxy end-capped PPEs as macro-initiators confirm the controlled/living nature of organo-catalyzed ROP of CPMs and pave the way to the synthesis of block copolymers based on polyphosphates. Finally, these polymerizations procedures are expected to facilitate the synthesis of well-defined PPEs with various architectures and free of potentially toxic metal remnants. The easy availability of catalysts, the mild conditions of polymerizations and the metal-free nature of the polymerizations makes these catalysts very attractive candidates for the synthesis of PPEs for biomedical applications such as drug and gene delivery, tissue engineering and dental applications. [less ▲]

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See detailSubjective self-ratings through a prolonged reading task in dysphonic versus normophonic female teachers
Remacle, Angélique ULg; Morsomme, Dominique ULg; Berrué, Elise et al

Poster (2012, May 10)

Aim: The purpose of this study was to evaluate the impact that a 2-hour reading task could have on ones voice in 16 normophonic and 16 dysphonic female teachers. Method and material: Teachers’ voices were ... [more ▼]

Aim: The purpose of this study was to evaluate the impact that a 2-hour reading task could have on ones voice in 16 normophonic and 16 dysphonic female teachers. Method and material: Teachers’ voices were orally loaded by reading a novel. They were instructed to read for imaginary students, as in their classroom. Voice intensity was constantly controlled between 70 and 75 dB. Every 30 minutes, participants were asked to answer the following questions using a 100-mm horizontal visual analogue scale: 1) How is your voice quality? 2) Do you feel any phonation effort? 3) Do you feel any vocal fatigue? and 4) Do you feel any laryngeal discomfort? Results and conclusions: For all subjective self-ratings, the repeated measures ANOVA demonstrated significant main effects of the duration (p < 0.0001) and of the group (p < 0.05). Subjects of both groups reported a worsening of their voice quality during the reading while phonation effort, vocal fatigue and laryngeal discomfort increased. Surprisingly, no significant interaction between duration and group was found. This means that subjective self-ratings realized before and during the reading task depict a similar evolution of both groups, while we expected more worsening of voice through time in the dysphonic group. [less ▲]

Detailed reference viewed: 42 (4 ULg)
See detailSynthesis of novel poly(N-vinyl amide)s containing copolymers by cobalt-mediated radical polymerization
Kermagoret, Anthony ULg; Hurtgen, Marie ULg; Liu, Ji ULg et al

Poster (2012, May 10)

Poly(N-vinyl amide)s are found in many applications due to their valued properties including water solubility, biocompatibility, metal-coordination ability, etc. Although N-vinyl amides are easily ... [more ▼]

Poly(N-vinyl amide)s are found in many applications due to their valued properties including water solubility, biocompatibility, metal-coordination ability, etc. Although N-vinyl amides are easily polymerized via radical pathways, their growing radicals are quite reactive due to the lack of stabilizing group, rendering the synthesis of well-defined poly(N-vinyl amide)s challenging. Thus, we explored the organometallic-mediated radical polymerization (OMRP) of a series of N-vinyl amides using bis(acetylacetonato)cobalt(II) as controlling agent in order to develop a platform for the precision synthesis of poly(N-vinyl amide)s. [less ▲]

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See detailThe Lactoperoxidase System, a soft chemical method to control of potato late blight
Bafort, Françoise ULg; Jijakli, Haissam ULg; Perraudin, Jean-Paul

Poster (2012, May 07)

Detailed reference viewed: 33 (5 ULg)
See detailGas migration in sea ice: from observations to modelling
Zhou, Jiayun ULg; Moreau, Sébastien; Vancoppenolle, Martin et al

Poster (2012, May 07)

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See detailIn vitro hemocompatibility of nanocarriers tailored for biopharmaceutical drugs.
Sevrin, Chantal ULg; Cerda Cristerna, Bernardino Isaac ULg; Lombart, François ULg et al

Poster (2012, May 06)

The optimization of nanoparticles (NP) for drug delivery, in particular to target the BBB, imposes to verify their hemocompatibility both for toxicological and efficiency of targeting perspectives. Indeed ... [more ▼]

The optimization of nanoparticles (NP) for drug delivery, in particular to target the BBB, imposes to verify their hemocompatibility both for toxicological and efficiency of targeting perspectives. Indeed the large surface they are able to expose to the biological environment promotes their interaction with various biochemicals, in particular proteins which can after adsorption elicit the activation of biological cascades either responsible from NP clearance or/and harmful body reaction (inflammatory / coagulation). In the frame of the European Integrated Project : “Nanobiopharmaceutics”, we have the opportunity to compare the hemoreactivity of about 145 different NP samples differing in core and surface chemistry and classified according to their expected difference in hydrophobicity based on the nature of their core materials. According to this classification, PLGA nanoparticles, polyglycidol-polyethyethylene oxide nanoparticles, polyglycidol thyolated or polyacrylamide nanogels, and polyelectrolyte complexes either based on polyamidoamine or poly(N,N-dimethylamino- 2-ethylmethacrylate) have been evaluated within a concentration ranging from 0.3 to 1000 μg/mL. These in vitro tests have been realized for screening purpose adopting normal human bloods and according to Iso 10993. As a summary of this extensive study, our results clearly highlight that most of the polymeric nanoparticles evaluated give rise to some alterations of the blood components. In particular the platelets, intrinsic pathway of coagulation and complement activation are the most reactive biological parameters in the presence of these nanostuctures. Although not strictly related to the surface chemistry our classification has also allowed us to derive some clear correlations between nanomaterial properties and their hemoreactivity. Within the class of polyelectrolyte electrolyte complexes, the modifications brought in the surface chemistry has drastically improved their hemoreactivity [less ▲]

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See detailMolecular biomimetics applied to medical devices
Van de Weerdt, Cécile ULg; Archembeau, Catherine; Vreuls, Christelle ULg et al

Poster (2012, May 05)

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See detailNEURAL CORRELATES OF GAIT HYPOKINESIA IN PARKINSON'S DISEASE: AN FMRI STUDY
Cremers, Julien ULg; Stamatakis, Julien; D'Ostilio, Kevin ULg et al

Poster (2012, May 05)

Introduction: Brisk walking (BW) is an efficient tool to study gait hypokinesia whose pathogenesis remains poorly understood in Parkinson's disease (PD). Aims: Assuming that brain regions recruited during ... [more ▼]

Introduction: Brisk walking (BW) is an efficient tool to study gait hypokinesia whose pathogenesis remains poorly understood in Parkinson's disease (PD). Aims: Assuming that brain regions recruited during imagined gait strongly overlap with those recruited during real gait, we used mental imagery of BW as a paradigm to study the neural correlates of gait hypokinesia in PD with BOLD fMRI. Methods: 15 'on-drugs' PD patients and 15 controls matched for age and gender were instructed to imagine themselves in two situations: comfortable walking (CW) and BW on a 25 meter-path. Imagined speed reserve (ISR), defined as the difference between imagined BW and CW speeds, was measured as a control of behavioral performance. The first-level individual contrast images representing the comparison between BW and CW were entered into second-level analyses with the corresponding ISRs as correlation regressors. Results: ISRs and their real counterparts measured offline were significantly decreased in patients relatively to controls. They strongly positively correlated in patients (Pearson's r = 0.88) and controls (Pearson's r = 0.59). Between-group comparison of individual contrasts BW minus CW in correlation with their corresponding ISRs showed that increasing imagined gait speed was strongly associated with increased activity of the left posterior parietal cortex (PPC) in controls and with decreased activity of this region in the patients. Conclusions: Our findings suggest that gait hypokinesia is related to an impaired function of the left PPC in PD. The left PPC may represent a target for therapeutic interventions aimed at alleviating gait disturbances in PD. [less ▲]

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See detailDynamic and region specific changes in estrogen production induced by reproductive stimuli.
de Bournonville, Catherine ULg; Dickens, Molly J; Ball, Gregory F et al

Poster (2012, May 04)

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See detailValidation of Adult Bone Marrow Stromal Cells in Cellular Therapy Protocols, using a Mouse Model for Parkinson’s Disease
Neirinckx, Virginie ULg; Laudet, Emerence; Rogister, Bernard ULg et al

Poster (2012, May 04)

Parkinson’s disease (PD) is the second most common neurodegenerative disorder in industrialized countries. Its main characteristic relies in a progressive loss of dopaminergic (DA) neurons in the ... [more ▼]

Parkinson’s disease (PD) is the second most common neurodegenerative disorder in industrialized countries. Its main characteristic relies in a progressive loss of dopaminergic (DA) neurons in the Substantia Nigra pars compacta (SNpc), resulting in a deficient dopamine release in the striatum and then promoting important defects in motility regulation. Unfortunately, motor symptoms are generally diagnosed once 80% of nigrostriatal neurons are already lost. The emergence of neuroprotective/-restorative strategies is then increasingly raising hope, and a lot of people now focus on cell therapy experiments. Adult bone marrow stromal stem cells (BMSCs) have already been demonstrated as ideal candidates for cell therapy in nervous lesions, regarding their high multipotency and the fact they can be easily harvested in the patient himself. After it has been demonstrated that some BMSCs arise from the embryonic neural crest (NC), we compared NC-BMSCs and mesenchymal (M)-BMSCs in vitro, in terms of differenciation abilities and more particularly in terms of neural fate. We then wanted to investigate and compare the potential usefulness of both populations in the context of a neurological pathology. We have validated a MPTP mouse model, mimicking the specific loss of nigral neurons, and started setting up a cell therapy experiment using stereotaxic brain injection of the two types of BMSCs. The survival rate of grafted cells was analyzed as well as their migration or differentiation, and their ability to restore neuronal loss was also observed. Our first results showed that once grafted inside the brain of MPTP mice, NC-BMSCs survive for about a week, staying tightly close to each other the injection track with no visible sign of migration. Afterwards, cells begin to disappear and we only observe a mean survival rate of 1% after 28 days. Looking at the nigrostriatal pathway integrity, neural crest-BMSCs don’t seem to induce any improvement: they don’t differenciate into neural cells, neither replace lost DA cells, and they do not induce any sprouting of surviving DA neurons. While the M-BMSCs graft experiment has to be completed, these first results showed that NC-BMSCs at the stem cell state are not able to restore the lesioned system, and maybe a pre-differenciation step would be required to trigger those cells into a neuronal fate before grafting them in a MPTP-mouse brain. [less ▲]

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See detailOncogenic human papillomavirus could directly interact with Natural Killer cells
Renoux, Virginie; Bastin, Renaud ULg; Boniver, Jacques ULg et al

Poster (2012, May 04)

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See detailEvidence for a partial epithelial-mesenchymal transition in postnatal stages of rat auditory organ morphogenesis
Johnen, Nicolas ULg; Cloes, Marie ULg; Thelen, Nicolas ULg et al

Poster (2012, May 04)

An epithelial-mesenchymal transition is a biological process that allows a polarized epithelial cell to undergo multiple biochemical changes that enable it to assume a mesenchymal cell phenotype. During ... [more ▼]

An epithelial-mesenchymal transition is a biological process that allows a polarized epithelial cell to undergo multiple biochemical changes that enable it to assume a mesenchymal cell phenotype. During this process, epithelial cells loosen cell-cell adhesion, module their polarity and rearrange their cytoskeleton: intermediate filaments typically switch from cytokeratin to vimentin. They also enhance their motility capacity. The epithelial-mesenchymal transition plays key roles in the formation of the body plan and in the differentiation of multiple tissues and organs but it is also involved in tissue repair, tissue homeostasis, fibrosis, and carcinoma progression. Until now, epithelial-mesenchymal transition has been rarely mentioned in the inner ear organogenesis. In chick, epithelial-mesenchymal transition has been reported as a possible mechanism of semicircular canal morphogenesis. More recently, an in vitro study has also indicated that sensory epithelial cells from mouse utricle can undergo an epithelial-mesenchymal transition to become cells expressing features of prosensory cells. By contrast, epithelial-mesenchymal transition has never been observed during auditory organ morphogenesis. The auditory organ, the organ of Corti, is a highly specialized structure composed by specific cellular types. The sensory cells are characterized by stereocilia at their apex and are necessary for the sound perception. Theses cells are supported by supporting cells. Based on their morphology and physiology, at least four types of supporting cells can be identified in the organ of Corti: inner and outer pillar cells, phalangeal cell and Deiter’s cells. The inner pillar cells and outer pillar cells combine to form the tunnel of Corti, a fluid filled triangular space that separates the single row of inner hair cells from the first row of outer hair cells. The Nuel spaces are another interval in the organ of Corti that is situated between the outer pillar cells and the different rows of outer hair cells and Deiters cells. To determine whether an epithelial-mesenchymal transition may play a role in the morphogenesis of the auditory organ, we studied the spatial localization of several epithelial-mesenchymal transition markers, the cell-cell adhesion molecules and intermediate filament cytoskeletal proteins, in epithelium of the dorsal cochlea during development of the rat organ of Corti from 18th embryonic day until 25th postnatal day. We examined by confocal microscopy immunolabelings on cryosections of whole cochleae with antibodies anti-cytokeratins as well as with antibodies anti-vimentin, anti-E-cadherin and anti-beta-catenin.Our results showed a partial loss of E-cadherin and beta-catenin between supporting cells at P8 and P12, respectively, and a temporary appearance of vimentin in pillar cells and Deiters between P8 and P10. Our results show a local loss of adhesion between supporting cells of the OC from P8, an increase expression of cytokeratins in supporting cells around P10 and a temporary appearance of vimentin in supporting cells at P8-10. These observations suggest that a partial epithelial-mesenchymal transition might be involved in the remodeling of the Corti organ during the postnatal stages of development in rat. [less ▲]

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See detailThe DBIRD complex: linking mRNA transcription to alternative splicing
Close, Pierre ULg; East, P; Svejstrup, J

Poster (2012, May 04)

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See detailUnravelling the roles of lysine acetylation by Elp3 during inner ear development
Mateo Sanchez, Susana ULg; Delacroix, Laurence ULg; Laguesse, Sophie ULg et al

Poster (2012, May 04)

The inner ear is composed of a vestibular part that controls balance, and the cochlea, which is dedicated to hearing. In both parts of the inner ear, sensory epithelia comprise supporting cells ... [more ▼]

The inner ear is composed of a vestibular part that controls balance, and the cochlea, which is dedicated to hearing. In both parts of the inner ear, sensory epithelia comprise supporting cells surrounding the sensory hair cells. These cells bear at their apical surface a staircase-structured hair bundle, consisting of multiple rows of actin-based stereocilia and a single tubulin-based kinocilium. This hair bundle allows the transduction from mechanical stimuli, initiated by sound or gravitational changes, to electrical signals that will then be transmitted by neurons from the spiral ganglion (innervating hair cells of the cochlea) or the vestibular ganglion. The inner ear organogenesis requires a tightly regulated transcriptional program that can be affected by post-transcriptional and post-translational modifications among which lysine acetylation. Given the importance of acetylation homeostasis in controlling developmental processes, we planned to investigate its role in inner ear formation and focused our attention on Elp3 acetyl-transferase, a member of the Elongator complex recently implicated in neurogenesis. First, we have analysed Elp3 expression by in situ hybridization on wild type mice at different developmental stages (from E11.5 until P6) and showed that it was expressed in the entire early otocyst at E11.5 and persisted later in the sensory epithelium of the cochlea (the organ of Corti), in the stria vascularis and in the vestibule. To study the functional consequences of protein acetylation by the Elongator complex in the inner ear, we studied conditional knock-out mice (Elp3 cKO) in which Elp3 is depleted from the otic vesicle at E8.5. These mice, at stage P15, showed obvious balance dysfunction that was confirmed by a complete battery of behavioural tests: stereotyped circling ambulation, head bobbing, retropulsion, and absence of reaching response in the tail-hanging test. Unfortunately, the Elp3 cKO mice die before the onset of hearing, thus precluding any evaluation of hearing disorders. Balance defects in mice depleted for Elp3 is not due to vestibular structural abnormalities, since paint-filling experiments showed a normal inner ear anatomy compared to wild type mice. Moreover, immunostainings in the vestibule and in the organ of Corti indicated that cell patterning was not impaired in the absence of Elp3 since specialised cells are present and correctly organised at embryonic day E18.5 and later on. However, we were able to detect some defaults in hair cell bundle integrity and orientation in the auditory portion of inner ear from Elp3 cKO mice. We were also able to demonstrate an increased level of apoptosis in the Elp3 cKO spiral ganglion at E14.5 leading to a reduced number of fibers innervating the cochlear hair cells at P0 and P15. In conclusion, we have confirmed the expression of Elp3 in the inner ear and pointed out a role for this acetyl-transferase in balance function. Our results clearly show the implication of Elp3 in ciliogenesis, hair cell innervation and neuronal survival and we plan to go deeper in the mechanisms involved through the identification of the proteins acetylated by Elp3. [less ▲]

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See detailGlobal analysis of gene expression in the skin of mice after a 92 days journey in microgravity.
Neutelings, Thibaut ULg; Liu, Y.; Cancedda, R. et al

Poster (2012, May 04)

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See detailApplication of molecular imaging in combination with quantitative proteomic approaches to determine the molecular players of adaptation to anti-angiogenic therapy in breast cancer.
Cimino, Jonathan ULg; Sounni, Nor Eddine ULg; Calligaris, David ULg et al

Poster (2012, May 04)

The recognition of the “angiogenic switch” as a rate-limiting secondary step in tumorigenesis led to extensive pre-clinical researches on angiogenesis and finally the approval of VEGF-neutralizing ... [more ▼]

The recognition of the “angiogenic switch” as a rate-limiting secondary step in tumorigenesis led to extensive pre-clinical researches on angiogenesis and finally the approval of VEGF-neutralizing antibodies (bevacizumab) and VEGF receptor tyrosine kinase inhibitors (RTKs:Sunitinib). The Sunitinib has been used clinically in patients with breast cancer refractory to other therapeutic agents. Unfortunately, like the cytotoxic therapies, these drugs do not produce lasting effects and resistance to treatment appeared clinically. Questions have emerged about the failure of anti-angiogenic therapy in clinic and the limitations of predictive preclinical models, and also about the molecular assessment of all stages of tumor adaptation and metastatic disease. To this end, we applied a quantitative proteomics and imaging mass spectrometry tools to visualize and study the profiles of proteins and small molecules associated with tumor treated or not with Sunitinib using a novel preclinical model of breast carcinoma cells. [less ▲]

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See detailModification de la gestion du dialogue intérieur des sportifs de haut niveau. Etude préliminaire
Lacrosse, Zoé; Godin, Philippe; Cloes, Marc ULg

Poster (2012, May)

Le dialogue intérieur est constitué de pensées qui sont généralement spontanées mais qui peuvent également être sous le contrôle direct du sportif. Selon Hatzigeorgiadis, Zourbanos, Galanis et Theodorakis ... [more ▼]

Le dialogue intérieur est constitué de pensées qui sont généralement spontanées mais qui peuvent également être sous le contrôle direct du sportif. Selon Hatzigeorgiadis, Zourbanos, Galanis et Theodorakis (2011), le discours peut revêtir une orientation pédagogique ou motivante. Ces auteurs ont montré que les pensées motivantes sont plus efficaces pour améliorer la performance dans des situations nécessitant un effort de longue durée ou de la force. Par contre, le discours pédagogique est plus utile pour les tâches qui demandent du temps et/ou de la précision. Les pensées spontanées des sportifs sont à 80% négatives. Il est donc logique de tenter de modifier cette situation afin d’augmenter la part des pensées opérationnelles (objectif clair, énoncé bref et simple phonétiquement, initiation d’un acte ou un geste concret, stimulation). Dans cette étude, nous testons une approche visant justement à amener des sportifs à mieux exploiter leur dialogue intérieur. Notre étude porte sur 5 joueuses de volley-ball de 2ème nationale belge (postes de jeu différents) provenant de deux équipes, toutes volontaires. Nous avons filmé une première confrontation entre ces deux formations. Sur base de l’enregistrement vidéo, nous avons effectué des entretiens stimulés individuels ciblant divers événements survenus lors de la rencontre. Ces retours sur la pratique nous ont permis d’identifier les pensées des joueuses. Par la suite, chacune de celles-ci a participé à deux séminaires individuels qui avaient pour objectif de modifier les pensées négatives et positives en pensées opérationnelles. A l’issue du match retour, nous avons répété une séance de rappel stimulé et avons complété la collecte des données par un débriefing général. Parmi les résultats que nous avons déjà mis en évidence, nous retiendrons que le discours pédagogique s’avère particulièrement pauvre par rapport au discours motivant. Des implications pratiques sont proposées. [less ▲]

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See detailProfiling the smell of death by TD-GCxGC-TOFMS
Stefanuto, Pierre-Hugues ULg; Stadler, S; Forbes, S et al

Poster (2012, May)

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See detailChemical control of Haplodiplosis marginata (Diptera: Cecidomyiidae)
Censier, Florence ULg; Chavalle, Sandrine ULg; Wittouck, Daniël et al

Poster (2012, May)

The saddle gall midge, Haplodiplosis marginata (von Roser), is a European pest of cereals. The larvae overwinter into the soil. Emergence of adult midges occurred during the spring and after mating ... [more ▼]

The saddle gall midge, Haplodiplosis marginata (von Roser), is a European pest of cereals. The larvae overwinter into the soil. Emergence of adult midges occurred during the spring and after mating, females lay their eggs on the leaves of cereals and several grasses. Eggs hatch a few days later; young larvae crawl to the stem and introduce themselves between the leaf sheath and the stem, were the larvae develop. As reaction of the presence of midge larvae, stem produce a longitudinal depression of 6-7 mm ended by two ridges looking as a horse saddle. When galls are numerous, they can cause break of stems and important yield losses. The saddle gall midge, which is a major pest in Central Europe, is not very well known in the Western part of the continent. It had already caused huge damage during outbreak periods. The last one reported in Belgium and in The Netherlands occurred between 1965 and 1970. Later, it was never reported again until 2010, where large populations and severe damage were observed, especially in the Flemish polders, a region with clay soils where wheat is cropped intensively. Faced with the resurgence of this pest, we sought to develop effective curative control. To date, crops chemical protection seems to be the only solution in case of heavy emergences. Experimentation was conducted in a highly infested field (Meetkerke, Belgian Polders), according to a randomized complete block arrangement with four replications. Foremost, a lambdacyhalothrin-based insecticide was used to evaluate efficiency of several protection schemes, ranging between one and four spray(s). The large spread of flights observed during the 2011 spring allowed to highlight the effect of treatment date on the attack intensity and also on the galls distribution along the stem, on the different internodes. Moreover, several insecticides already registrated in cereals against aphids were compared for their efficacy against saddle gall midge. Studied pyrethroids have shown a very good efficacy, ranging between 75 % and 87 %, when applied twice with a 2 weeks interval. To be efficient, chemical spray must be synchronized with the flights and egg laying periods. Monitoring the phenology of flights is thus essential as part of integrated pest management against saddle gall midge. [less ▲]

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See detailTerqa Ceramic Culture during the 3rd Millennium BC. Material from 18th-26th Excavation Campaigns
Mas, Juliette ULg

Poster (2012, May)

Terqa, an important Syrian Bronze Age site located in the Lower Middle-Euphrates region, benefited from a key position which provided the settlement with the opportunity to gain from exchanges and ... [more ▼]

Terqa, an important Syrian Bronze Age site located in the Lower Middle-Euphrates region, benefited from a key position which provided the settlement with the opportunity to gain from exchanges and innovations arriving from both the North and South, while developing its own identity and culture. A new study on pottery has just been carried out on 3rd-millennium material from eight excavation seasons. The recovered material has been used to specify Terqa’s chronostratigraphy with greater accuracy, comparing it with the neighboring site of Mari and other contemporary ones but also providing us with a preliminary overview of Terqa’s ceramic culture during the Early Bronze Age. [less ▲]

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See detailSequential T2 Relaxometry as a Non-Invasive Assessment of Transmural Inflammation in a Murine Model of Chronically Relapsing Colitis
Breynaert, C; Dresselaers, T; Cremer, J et al

Poster (2012, May)

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See detailReference visualization and download analysis of the “geographical literature” in the Open Repository of ULg (ORBi)
Stirbu, Simona ULg; Thirion, Paul ULg; Schmitz, Serge ULg et al

Poster (2012, May)

Set up by the University of Liège, ORBi (Open Repository and Bibliography) knew a lightning increase of the online posted references since its creation in 2008. The official launch took place on November ... [more ▼]

Set up by the University of Liège, ORBi (Open Repository and Bibliography) knew a lightning increase of the online posted references since its creation in 2008. The official launch took place on November 26th, 2008 and after considerable efforts on behalf of the team which manages the tool, and researchers who introduce themselves their publications, the contents of the repository managed to reach a value of 64245 references among which 38670 with full text. Working for the Library of Geography of the University of Liege, I found interesting to analyze the number of visualizations and downloads of the references (2005 to 2007) posted online by the ULg geographer’s, and the population interested in this literature. The highlight is on WHO and WHERE are the internet users visualizing and downloading ORBi references from? In order to detect the population using this scientific literature, we analyzed the user IP and their distribution in the world. The data was obtained from a MaxMind database. The type of population using this scientific literature: researchers, individuals, public or private companies was also determined. [less ▲]

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See detailUn environnement d'apprentissage en ligne pour aider les futur(e)s logopèdes/orthophonistes à travailler la langue française
Jacquet, Maud ULg; Maes, Estelle ULg; Maillart, Christelle ULg et al

Poster (2012, May)

Cette communication présente un dispositif qui propose un environnement en ligne pour aider les étudiants de logopédie à piloter leur trajectoire de formation afin d'avancer de façon autonome vers la ... [more ▼]

Cette communication présente un dispositif qui propose un environnement en ligne pour aider les étudiants de logopédie à piloter leur trajectoire de formation afin d'avancer de façon autonome vers la maîtrise de la langue française. Elle en explique les modalités, les résultats et les régulations par ailleurs pour la plupart déjà réalisées. [less ▲]

Detailed reference viewed: 132 (17 ULg)
See detailFluxes of dimethylsulfide from warming sea ice
Carnat, Gauthier; Zhou, Jiayun; Papakyriakou, Tim et al

Poster (2012, May)

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See detailUse of Near Infrared and Raman spectroscopy for the optimization of API layer of pharmaceutical tablet
Chavez, Pierre-François ULg; Mantanus, Jérôme; Cuypers, Serge et al

Poster (2012, May)

Detailed reference viewed: 72 (20 ULg)