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See detailEvaluation des effets à court terme de l’intervention « Bouger plus » sur la pratique d’activité physique des seniors
Rompen, Jérôme ULg; Mouton, Alexandre ULg; Grimont, Pierre et al

Poster (2014, July 03)

Des outils basés sur un site internet sont efficaces pour promouvoir l’activité physique (AP) chez les seniors (Ammann et al., 2013). Cette étude avait pour but d’évaluer les effets de l’intervention « ... [more ▼]

Des outils basés sur un site internet sont efficaces pour promouvoir l’activité physique (AP) chez les seniors (Ammann et al., 2013). Cette étude avait pour but d’évaluer les effets de l’intervention « Bouger plus » sur la pratique d'AP de sujets de 50 ans et plus, au sein d’une commune. Quatre groupes ont reçu une intervention différente pendant trois mois : un site internet (I), un cours collectif (CC), une combinaison des deux (CCI) et pas d'intervention (CO). Des questionnaires ont permis d’évaluer les résultats. Ceux-ci montrent une évolution positive du stade de changement de comportement vis-à-vis de l’AP, au cours de l’intervention, pour les groupes I et CCI. De plus, le niveau de pratique est resté stable malgré la période hivernale pour les groupes CC et CCI alors qu’il a chuté pour le groupe CO. L’intervention a donc eu des effets positifs à court terme sur les comportements en matière d’AP, particulièrement quand le site internet et les cours collectifs étaient combinés. [less ▲]

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See detailAnalyse qualitative du fonctionnement du centre de formation d’une fédération sportive
Lacrosse, Zoé ULg; Martin, Valentine; Cloes, Marc ULg

Poster (2014, July 03)

Cette étude qualitative analyse le fonctionnement d’un centre de formation pour jeunes athlètes de haut niveau dont la finalité consiste à leur permettre de mener conjointement leurs études et leur ... [more ▼]

Cette étude qualitative analyse le fonctionnement d’un centre de formation pour jeunes athlètes de haut niveau dont la finalité consiste à leur permettre de mener conjointement leurs études et leur carrière sportives. Dans la perspective d’aider la structure à améliorer ce qui est mis en place, notre objectif consiste à décrire la situation actuelle. D’un point de vue pratique, nous avons interrogé les dirigeants (n=4) du centre, les sportifs (n=34), leurs parents (n=10), les coaches (n=3) ainsi que plusieurs intervenants externes (médecin, directeur d’école, etc. ; n = 3). Nous avons également réalisé un certain nombre d’observations informelles et collecté des questionnaires permettant de faire émerger le ressenti des joueurs quant à leur vie au sein du centre. Les résultats indiquent (a) un manque de suivi diététique et psychologique, (b) des relations relativement bonnes entre les acteurs sauf entre les joueurs et les éducateurs et, (c) la nécessité d’améliorer les infrastructures. [less ▲]

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See detailComparaison du niveau d’estime de soi dans deux populations ayant des caractéristiques démographiques différentes : des arbitres et des non-arbitres
Van Hoye, Martin ULg; Cloes, Marc ULg

Poster (2014, July 03)

Si le sport forge le caractère, l’arbitrage devrait également responsabiliser les individus qui l’exercent. Aussi, on peut considérer que les arbitres pourraient développer une meilleure estime d’eux ... [more ▼]

Si le sport forge le caractère, l’arbitrage devrait également responsabiliser les individus qui l’exercent. Aussi, on peut considérer que les arbitres pourraient développer une meilleure estime d’eux-mêmes ? Dans cette recherche, nous avons tenté de vérifier cette hypothèse en analysant le niveau d’estime de soi de deux échantillons distincts : des arbitres de basket-ball (n=163) et des personnes n’ayant aucune expérience au niveau de l’arbitrage (n=163). L’instrument que nous avons utilisé est « l’Echelle de l’Estime de Soi » (EES). La moyenne générale au questionnaire est légèrement supérieure chez les arbitres (30,9 vs 30,5) mais il ne s’agit pas d’une différence significative (p=0,8372). L’ancienneté dans l’arbitrage ou l’âge des individus ne semblent pas être un facteur influençant l’estime de soi des arbitres. Il conviendrait de vérifier s’il en est de même dans les autres disciplines sportives que le basket-ball. [less ▲]

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See detailMolecular adaptations in mouse skeletal muscle following eccentrically versus concentrically biased training
Hody, Stéphanie ULg; Lacrosse, Zoé ULg; Simonet, Arnaud et al

Poster (2014, July 02)

Introduction The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human ... [more ▼]

Introduction The molecular adaptations specifically induced by different muscle contraction types have only been partially elucidated. We previously demonstrated that eccentric contractions in human quadriceps elicited proteome modifications that suggest a muscle fiber typology adaptation (Hody et al. 2011). We address this question in a more systematic way by examining the effects of different running modes on the mouse muscle proteome and the muscle fiber typology on the whole quadriceps. Methods Male adult mice (C57BL6) were randomly divided into downhill running (DHR, quadricipital eccentrically biased contractions), uphill running (UHR, quadricipital concentrically biased contractions) and untrained control (CONT) groups. Running groups performed five training sessions on an inclined treadmill for 75 to 135 min/day and the quadriceps muscles were dissected 96 hours after the last session. Muscle protein extracts of DHR and UHR groups (n=4/group) were subjected to a 2D-DIGE analysis coupled with mass spectrometry. The assessment of fiber type, size and number was performed on the rectus femoris of the three groups (n=6/group) using myosin heavy chain (MHC) immunofluorescence. Results In the proteomic analysis, eight spots identified as the fast MHC isoforms exhibited a lower abundance in DHR compared to UHR (p<0.05, t-test). In contrast, ATP synthase subunit a and tubulin ß were more expressed in DHR (p<0.05). Immunohistological analysis revealed a significant higher proportion of type I and IIa fibers for DHR compared to UHR or CONT groups (p<0.05, one-way ANOVA). Discussion Our data demonstrate that the eccentrically biased contractions in mice induced specific adaptations in protein expression as well as in muscle fiber type and size which may reflect a more oxidative muscle phenotype. The differences in stress placed on the muscle between both trainings may be responsible for some unique adaptations resulting from the eccentrically biased training. Eccentric training is known to protect skeletal muscles against exercise-induced muscle damage (EIMD) which may occur after intense eccentric contractions (Chen et al. 2010; Hody et al. 2011). It is also suggested that fast glycolytic muscle fibers are more vulnerable to EIMD than oxidative fibers (Lieber and Friden, 1988). Therefore, it would be interesting to investigate whether the molecular changes induced by an eccentrically biased training are involved in protection against EIMD. References Chen TC, Chen HL, Lin MJ, Wu CJ, Nosaka K. (2010). Med Sci Sports Exerc 42, 1004-1012. Hody S, Leprince P, Sergeant K, Renaut J, Croisier JL, Wang F, Rogister B. (2011). Med Sci Sports Exerc 43, 2281-2296. Lieber RL, Friden J. (1988). Acta Physiol Scand 133, 587-588. [less ▲]

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See detailX-ray emission from magnetic massive stars
Nazé, Yaël ULg; Petit, V.; Rindbrand, M. et al

Poster (2014, July 01)

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. In an attempt to clarify the systematics of the observed X-ray properties, we have analyzed a large ... [more ▼]

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. In an attempt to clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM observations, corresponding to over 100 exposures of 60% of the known magnetic massive stars listed recently by Petit et al. (2013). We notably show that the X-ray luminosity is strongly correlated with mass-loss rate, in agreement with predictions of magnetically confined wind models. We also investigated the behavior of other X-ray properties (plasma temperature, absorption, variability), yielding additional constraints on models. This work not only advances our knowledge of the X-ray emission of massive stars, but also suggests new observational and theoretical avenues to further explore magnetically confined winds. [less ▲]

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See detailAre agricultural ecosystems important BVOC « exchangers »? Evidences from 2 measurement years on croplands at Lonzée (Belgium)
Bachy, Aurélie ULg; Aubinet, Marc ULg; Schoon, Niels et al

Poster (2014, July 01)

For the last decades, agricultural ecosystems have been a key biome for diverse socio-economical, environmental and climatic issues. And one of these climatic issues is just BVOC (Biogenic Volatile ... [more ▼]

For the last decades, agricultural ecosystems have been a key biome for diverse socio-economical, environmental and climatic issues. And one of these climatic issues is just BVOC (Biogenic Volatile Organic Compounds) emission from terrestrial ecosystems. Indeed, those compounds which are mostly emitted by plants play a great role in the atmospheric chemistry, thereby influencing the Earth surface radiative budget and the tropospheric air quality. However, so far, very few is known about BVOC exchange by crops, implying that huge uncertainties remain about qualifying, quantifying and determining sources/sinks and driving mechanisms of BVOC exchanges between croplands ecosystems and the atmosphere. We present here the first long term BVOC fluxes measurement study conducted on maize (2012) and winter wheat (2013), respectively the second and first most important worldwide crops (FAOSTAT). BVOC exchange was measured using the disjunct by mass scanning eddy covariance technique (+ PTR-MS, Ionicon) at the Lonzée Terrestrial Observatory (ICOS site) in Belgium. Main results are: (i) crops emit mainly methanol; (ii) BVOC fluxes from studied crops is lower than in literature, suggesting that agricultural ecosystems are poor BVOC exchangers; (iii) soil is a significant BVOC source. [less ▲]

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See detailThe X-ray bright massive stars in Cyg OB2
Nazé, Yaël ULg; Cazorla, Constantin ULg; Rauw, Grégor ULg

Poster (2014, July 01)

As a complement to the results from the Cyg OB2 Chandra Legacy program, we present in this contribution the detailed analysis of the four X-ray bright massive stars dominating the cluster. Cyg OB2 #5, #8A ... [more ▼]

As a complement to the results from the Cyg OB2 Chandra Legacy program, we present in this contribution the detailed analysis of the four X-ray bright massive stars dominating the cluster. Cyg OB2 #5, #8A, and #9 are binary or multiple massive stars in the Cyg OB2 association displaying several peculiarities, such as bright X-ray emission and non-thermal radio emission. Our X-ray monitoring of these stars reveals the details of their behavior at high energies, which can be directly linked to wind-wind collisions (WWCs). In addition, the X-ray emission of Cyg OB2 #12, an evolved massive star, shows a long-term decrease, which could hint at the presence of a companion (with associated colliding winds) or indicate the return to quiescence of the system following a recent eruption. [less ▲]

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See detailSpatiotemporal distribution of last 500 yrs turbidites in the Western Gulf of Corinth, Greece: implications for the characterization of historical earthquakes
Beckers, Arnaud ULg; Hubert, Aurelia ULg; Beck, Christian et al

Poster (2014, July 01)

The Corinth rift is one of the fastest spreading rifts on Earth. 10 earthquakes of magnitude greater than 6 occurred during the last century. The question of seismic hazard is consequently particularly ... [more ▼]

The Corinth rift is one of the fastest spreading rifts on Earth. 10 earthquakes of magnitude greater than 6 occurred during the last century. The question of seismic hazard is consequently particularly relevant. Despite a long earthquake catalogue, estimations of earthquake hazard remain problematic because of the difficulty to associate each historical event to one of the many active faults mapped in the area. Consequently, combining seismology, history and paleoseismology in an interdisciplinary approach is here necessary and is the goal of the ANR-SISCOR project. In this framework, we investigated the offshore sediments in order to (1) better constraint the length of the active offshore faults, and (2) look for sedimentary signature of historical earthquakes. 600 km of high resolution seismic reflexion data have been acquired during two surveys and 12 short gravity cores have been retrieved. The latters are 0.5 to 1 m long, allowing us to analyze about 500 yrs of sedimentation. Two new faults potentially able to trigger M>5.5 earthquakes have been mapped in the northern part of the gulf based on seismic data. Sedimentary events (turbidites sensu lato) have been identified in some cores, essentially in the deep basin and in a 180m-deep sub-basin close to the northern coast. The comparison with the critically reviewed historical records shows that some of these events could have been triggered by historical earthquakes. The link between these potential earthquakes sedimentary signatures, historical events and active faults is discussed based on intensity maps and our new active fault map. [less ▲]

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See detailHighly dispersed iron xerogel catalysts for p-nitrophenol degradation by photo-Fenton effects
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Zubiaur, Anthony ULg et al

Poster (2014, July)

Since the beginning of the industrial era, the various human activities have increased steadily, leading to a rapid technological development and a high population growth. Thus, the expansion of the ... [more ▼]

Since the beginning of the industrial era, the various human activities have increased steadily, leading to a rapid technological development and a high population growth. Thus, the expansion of the industry has heavily polluted the atmosphere, soil and water with negative consequences for humans and environment [1]. To decrease this pollution, it exists various treatment methods: chemical, physical and biological [2,3]. Among all these methods, a recent way of treatment is the degradation of pollutants in soils or waters by Fenton and photo-Fenton reactions [3] which use H2O2, iron-based compounds and UV light. In this way, several Fe2O3/SiO2 xerogel catalysts were synthesized by cogelation method by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions [4]. Five samples were synthesized: four samples with different percentage of iron (0.5, 1, 1.5 and 2.5 theoretical wt% confirmed by ICP-AES measurements), and a sample of pure silica. TEM pictures, nitrogen adsorption-desorption and mercury porosimetry measurements have established that EDAS plays a role of nucleating agent of silica particles [5,6] and allows to anchor iron particles inside silica network [4]. Indeed, it results iron nanoparticles of diameter 1-1.5 nm encapsulated in silica particles with sizes of about 10-30 nm in diameter. The species of iron was determined by Mössbauer spectroscopy and only Fe3+ ions were observed in xerogel catalysts. Then, the Fenton and photo-Fenton effect of these catalysts were evaluated on the degradation of p-nitrophenol (PNP) in aqueous medium in different conditions. Results show that Fe2O3/SiO2 xerogels present a photo-Fenton effect with H2O2, reaching with a sample 99 % of degradation after 24 h. [1] M. A. Khan, A. M. Ghouri, Environmental pollution: its effects on life and its remedies, Journal of Arts, Science & Commerce (Vol. 2), 2011, pg 276-285. [2] M. S. Kuyukina , I. B. Ivshina, Biology of rhodococcus: chapter 9, Springer, 2010, pg 232-256. [3] J. J. Pignatello, E. Oliveros, A. MacKay, Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry, Critical Reviews in Environmental Science and Technology (Vol. 36), 2006, pg 1-84. [4] B. Heinrichs, L. Rebbouh, J.W. Geus, S. Lambert, H.C.L. Abbenhuis, F. Grandjean, G.J. Long, J.-P. Pirard, R.A. van Santen, Iron (III) species dispersed in porous silica through sol-gel chemistry, Journal of Non-Crystalline Solids (Vol. 354), 2008, pg 665-672. [5] S. Lambert, C. Alié, J.-P. Pirard, B. Heinrichs, Study of textural properties and nucleation phenomenon in Pd/SiO2 , Ag/SiO2 and Cu/SiO2 cogelled xerogel catalysts, Journal of Non-Crystalline Solids (Vol. 342), 2004, pg 70-81. [6] B. Heinrichs, S. Lambert , N. Job , J.-P. Pirard, in "Catalyst Preparation: Science and Engineering, J. R. Regalbuto (Ed.)", CRC Press, Taylor & Francis Group, Boca Raton, 2007, p. 163-208. [less ▲]

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See detailSynthesis of Pt/Carbon Xerogel Electrocatalysts for PEM Fuel Cells by the Multiple SEA Method
Zubiaur, Anthony ULg; Chatenet, Marian; Maillard, Frédéric et al

Poster (2014, July)

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See detailHigh throughput sequencing analysis reveals genetic variability and selection pressure in different murine norovirus genomic regions during in vitro replication
Mauroy, Axel ULg; Taminiau, Bernard ULg; Nezer, Carine et al

Poster (2014, July)

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most ... [more ▼]

Murine norovirus (MuNoV), a single stranded positive sense RNA virus belonging to the Caliciviridae family, is considered as a representative model for human norovirus infections, one of the most important etiological cause of both epidemic and sporadic gastroenteritis cases worldwide. Four open reading frames are described into its genome: ORF1 codes the non-structural (NS) proteins, including the viral RNA dependent RNA polymerase (RdRp); ORF2 codes the single capsid protein (VP1), wherein two domains are present: a relatively conserved domain (“shell”) and a more variable domain (“protruding”); ORF3 codes a minor structural protein; and ORF4, currently only found in viruses genetically related to MuNoV codes a virulence factor. In this study, we demonstrated by high throughput sequencing that, during serial passages of MuNoV in cell culture, the substitution rates, estimated by Bayesian inferences, did not significantly differ across the five targeted genomic regions except one. These rates were similar in four genomic regions encompassing partial non-structural 1-2 protein (NS1-2)-, NS5-, NS6-, NS7 (RdRp)- and VP1-coding sequences (coding the conserved part of the protein also including the ORF4 region). In the partial minor structural protein-coding region, this substitution rate was however estimated to be at least one log higher when expressed as substitution/site/day. The precise localisation of the detected nucleotide point mutations (substitution, deletion and insertion) were reported as well as the quantitative increase or decrease of the sequences harbouring them along ten cell culture passages. The non-silent amino acid mutations were also depicted in 3D models for four out of the five studied regions. These results have important implications for different norovirus research fields, especially in terms of diagnosis, classification methodology and genetic evolution. [less ▲]

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See detailDroplet synchronization in multiple interconnected parallel channels
Van Loo, Stéphanie ULg; Stoukatch, Serguei ULg; Gilet, Tristan ULg

Poster (2014, July)

In droplet microfluidics, the pairing of droplets in parallel channels is sometimes required, e.g. to control their encounter and to promote their coalescence. Prakash and Gershenfeld [1] showed that ... [more ▼]

In droplet microfluidics, the pairing of droplets in parallel channels is sometimes required, e.g. to control their encounter and to promote their coalescence. Prakash and Gershenfeld [1] showed that passive synchronization could be achieved with bubbles in a ladder-like channel network. Bubbles flow in the rails and induce recirculation in the interconnecting rungs, which supposedly provides the feedback and subsequent synchronization. Ahn et al. recently extended this study to trains of droplets in flow-rate-driven conditions [2]. We here present an extensive experimental and theoretical investigation of droplets synchonization in multiple parallel channels. Droplets are produced with independent flow-focusing structures. Several experimental conditions are tested, including several geometries (and subsequent flow resistance) and inlet conditions (pressure-driven vs. flow-rate-driven). An extension to three rails is also considered. The microfluidic chips are designed with the help of a lumped-element model in which droplets are driven by the flows. [1] M. Prakash and N. Gershenfeld, Science 2007, 315, 832-835 [2] Ahn et al., Lab-on-a-chip, 2011, 11, 3956-3962 [less ▲]

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See detail3D analysis and determination of stride parameters for different type of foot strike in running
Deflandre, Dorian ULg; Bury, Thierry ULg; Schwartz, Cédric ULg et al

Poster (2014, July)

The purpose of the study was to compare methods for the determination of foot strike and toe off for runners with different foot strike patterns. A 3D optoelectronic system usually used in motion ... [more ▼]

The purpose of the study was to compare methods for the determination of foot strike and toe off for runners with different foot strike patterns. A 3D optoelectronic system usually used in motion laboratories was compared with tools commonly used on the field: an optical based detection system (OptoGait) and an accelerometer based system (Myotest). [less ▲]

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See detailMetacognition and school learning: Use of the DELV program in primary school
Nobile, Debora ULg; Frenkel, Stéphanie ULg

Poster (2014, July)

In the framework of self-regulated learning theories, the DELV (“Understanding one’s own learning”) is a 165-page metacognitive intervention program developed by Büchel & Büchel (1995, 1997, 2009, 2010 ... [more ▼]

In the framework of self-regulated learning theories, the DELV (“Understanding one’s own learning”) is a 165-page metacognitive intervention program developed by Büchel & Büchel (1995, 1997, 2009, 2010, 2011). It includes 8 types of decontextualized exercises which notably allow to develop the learner’s metacognitive knowledge and skills (for more details, see Büchel, 2013). They also make it possible to work on cognitive and psycho-affective aspects. Transfer can thus be better developed. This tool is really useful (for more details, see Berger & Büchel, 2013) and, in our opinion, still not sufficiently known. Our main purpose is to present (a) its objectives, (b) the variables worked on (cognitive, metacognitive and psycho-affective), (c) possible uses in a school context within classes (e.g., the “sandwich method”) and (d) the outcome we can expect. References - Berger, J.-L., & Büchel, F.P. (2013), L’autorégulation de l’apprentissage: Perspectives théoriques et applications. Nice, France: Les Editions Ovadia. - - Büchel, F.P. (2013). Le programme DELV – Comprendre son propre apprentissage. Evaluation scientifique auprès d’enfants et d’adolescents sans ou avec difficultés d’apprentissage. In J.-L. Berger & F.P. Büchel (Eds.), L’autorégulation de l’apprentissage: Perspectives théoriques et applications (pp. 293-336). Nice, France: Les Editions Ovadia. - Büchel, F.P. & Büchel, P. (1995). Découvrez vos capacités, rEalisez vos possibilités, pLanifiez votre démarche, soyez créatiFs. Le programme DELF. Russin, Switzerland: Centre d’éducation cognitive. - Büchel, F.P., & Büchel, P. (1997). DELV. Das Eigene Lernen Verstehen. Ein Programm zur Förderung des Lernens und Denkens für Jugendliche und Erwachsene. Aarau, Switzerland: Sauerländer. - Büchel, F.P. & Büchel, P. (2009). DELV. Das Eigene Lernen Verstehen. Ein Programm zur Förderung des Lernens für Jugendliche und Erwachsene (3. vollständig überarbeitete Auflage). Berne, Switzerland: h.e.p. Verlag. - Büchel, F.P. & Büchel, P. (2010). DELV. Das Eigene Lernen Verstehen. Ein Programm zur Förderung des Lernens für Jugendliche und Erwachsene (4. überarbeitete Auflage). Berne, Switzerland: h.e.p. Verlag. - Büchel, F.P. & Büchel, P. (2011). DELV. Comprendre son propre apprentissage. Tegna, Switzerland: Centre d’éducation cognitive. [less ▲]

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See detailAre you sure this was your own idea?
Beaufort, Aline ULg; Brédart, Serge ULg; Dehon, Hedwige ULg

Poster (2014, July)

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See detailValidation of a new automatic drowsiness quantification system for drivers
Wertz, Jérôme ULg; François, Clémentine ULg; Verly, Jacques ULg

Poster (2014, July)

Drowsiness is a major cause of various types of accidents, and particularly of driving accidents. Scientific studies report that drowsiness would be responsible for 20 to 30% of driving accidents ... [more ▼]

Drowsiness is a major cause of various types of accidents, and particularly of driving accidents. Scientific studies report that drowsiness would be responsible for 20 to 30% of driving accidents. Drowsiness can result from, among others, sleep deprivation, sleep disorders, alcohol, some medications, or performing a monotonous task. While all persons are likely to be drowsy at some point during the day, some persons are more prone than others to being drowsy at almost any time of the day; e.g. 6 to 11% of the population suffers from severe chronic excessive daytime sleepiness. Three main classes of methods can be used to characterize the level of drowsiness of a driver without disturbing him. These classes are respectively related to vehicle behavior (e.g. via lateral movements), driver behavior (e.g. via steering wheel movements), and driver physiological state (e.g. via eye movements). Since drowsiness is a physiological state, it seems particularly meaningful to use physiology-based methods to characterize it. Among these, the most significant ones rely on polysomnography and/or oculography. Polysomnography is viewed by some practitioners as the reference in the domain, but it is very sensitive to artifacts, and it is not very practical for use while driving. Ocular parameters are recognized to be good and reliable physiological indicators of drowsiness, and, thus, oculography seems to be the most sensible way to characterize drowsiness in practice. We have thus developed an experimental, fully automatic drowsiness monitoring system (software/algorithms) based on the physiological state of a person. This system uses ocular parameters extracted from images of the eye (i.e. photooculography) to determine a level of drowsiness on a continuous numerical scale from 0 to 10, with 0 corresponding to "very awake" (or "very vigilant") and 10 to "very drowsy". The ultimate goal of this system is to prevent drowsiness-related accidents for driving and other applications. The reported study shows that our system exhibits promising capability for road safety. Fourteen healthy volunteers (7 M, 7 F, mean age 23.7, range 21-33 years) participated in an experiment in a driving simulator, where they were asked to perform three driving sessions/runs (two of 45 minutes and one of 60 minutes) in different sleep-deprivation conditions (with up to 28 hours of complete sleep deprivation). During each session, we recorded both a high frame rate video of one eye and a set of driving parameters. Subsequently, for each successive minute in the session, we used our algorithms to extract ocular parameters from the video images and to produce a level of drowsiness, and we computed the standard deviation of lateral position (SDLP) from the driving parameters. The results show (1) that the (computed) SDLP increases when the (computed) level of drowsiness increases, and (2) that the level of drowsiness increases when the level of sleep deprivation increases. These results indicate that our algorithms for producing a level of drowsiness work in a meaningful way. The experiment protocol was approved by the Ethics Committee of our university. [less ▲]

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See detailA parent-implemented language intervention in lower socioeconomic status populations
Martinez Perez, Trecy ULg; Leclercq, Anne-Lise ULg; Mulquet, Amandine et al

Poster (2014, July)

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See detailBiological indicators of soil quality over landscape spatial scales: a case study in Southern Belgium
Krüger, Inken ULg; Chartin, Caroline; Van Wesemael, Bas et al

Poster (2014, July)

Biological indicators are organisms or biological processes whose values give quantitative information on the capacity of a soil to function. Their fast dynamic allows to detect changes on short ... [more ▼]

Biological indicators are organisms or biological processes whose values give quantitative information on the capacity of a soil to function. Their fast dynamic allows to detect changes on short timescales. Five biological indicators (basal respiration, nitrogen mineralisation, microbial carbon and nitrogen, earthworm abundance and biomass, functional microbial diversity) as well as two ecophysiological indices (microbial quotient and metabolic quotient) were tested for their power to characterize the biological soil quality on a landscape level at 60 sites in two South-Belgian landscape units were investigated. All biological indicators differed significantly between the two landscape units showing the biological indicators to be discriminatory on a landscape level. Within each landscape unit, no relationships between biological indicators were found, underlining the need to measure multiple biological indicators. The results represent the first data for a South-Belgian monitoring network of biological soil quality. [less ▲]

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See detailSentence repetition task as a powerful diagnostic tool in French children with SLI
Leclercq, Anne-Lise ULg

Poster (2014, July)

Sentence repetition is considered as a psycholinguistic marker of specific language impairment (SLI) (i.e., Redmond et al., 2011). However, little is known about specificity and sensitivity for most ... [more ▼]

Sentence repetition is considered as a psycholinguistic marker of specific language impairment (SLI) (i.e., Redmond et al., 2011). However, little is known about specificity and sensitivity for most language tests, especially in French (Thordardottir et al., 2011). This study aims at assessing the specificity and sensitivity of a sentence repetition task frequently used in clinical evaluations (Chevrie-Muller et al., 2010). This task could be especially interesting because clinicians can compute separate linguistic scores depending on the answers produced by the children, enabling them to get a glimpse of the areas of language difficulties in these children. Fourty-four school-age children with SLI, and 34 age-and-IQ-matched controls participated in this study. Children with SLI were diagnosed by certified speech-language pathologists and attained specific language classes in special needs schools from at least one year. Moreover, they scored more than -1.25 SD below expected normative performance in at least 2 language areas on other standardised tests used in previous studies including French children with SLI. Results show that both sensitivity and specificity of general scores were high (over 80%) at three cut-off points widely used in clinical practice: -1SD, -1.25 SD, -2 SD. Moreover, an exploratory factorial analysis indicates that two distinct factors can be dissociated in children productions: a morphosyntactic factor and a lexico-semantic factor, together explaining 96.48% of the variance in production scores. These results reveal that the sentence repetition task is a powerful diagnostic tool in French children with SLI. [less ▲]

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See detailMolecular detection of six high importance endosymbiotic bacteria in Belgian wild-caught mosquitoes
Raharimalala, Fara Nantenaina ULg; Boukraa, Slimane ULg; Bawin, Thomas ULg et al

Poster (2014, July)

Introduction Several disease vectors presented a resistance to various pesticides currently used. One of an alternative solution was to use endosymbiotic bacteria because their probably interactive ... [more ▼]

Introduction Several disease vectors presented a resistance to various pesticides currently used. One of an alternative solution was to use endosymbiotic bacteria because their probably interactive effects with their host. According to the introduction risks of mosquito born disease and their dispersion, we propose to investigate the prevalence of six endosymbiontic bacteria in wild-caught Culicidae in Belgium. Methods Eleven species of Belgian fields mosquitoes (Culex pipiens s.l., Cx. torrentium, Cx. hortensis, Anopheles claviger, An. maculipennis s.l., An. plumbeus, Culiseta annulata, Ochlerotatus geniculatus, Oc. dorsalis, Aedes albopictus and Coquillettidia richiardii) were used for the screening of six genera endosymbiotic bacteria (Wolbachia sp., Commamonas sp., Delftia sp., Pseudomonas sp., Acinetobacter sp. and Asaia sp.) according to their possible impact in mosquito biology. PCR was done for the screening and positives bands were sequenced and deposited in GenBank. Results Total of 144 larvae and 32 adults were used. Wolbachia, Pseudomonas, Acinetobacter and Asaia were found in mosquitoes with different proportions, according to stages (adults, larvae) with a predominance of Pseudomonas in all species, as far as Acinetobacter and Asaia also have a high prevalence. Commamonas and Delftia were absent from all species tested, either in larvae and in adults. Discussion Choice of endosymbiotic bacteria studied here was allowing of their importance in literature. For Pseudomonas, it showed that this bacteria could produced ovipositon attractants for mosquito. Acinetobacter was suggested efficient in transmission and maintenance within host populations. Asaia was capable of efficiently crossing body barriers and colonizing different organs. Wolbachia was currently the most studied bacteria which plays an important role in the genetic manipulation of the host. Present advances in understanding the mosquito–microbiota relationships may have a great impact in a better understanding of some traits of mosquito biology and in the development of innovative mosquito-borne disease-control strategies. [less ▲]

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See detailThe Amik Lake in Southern Turkey over the last 4000 years, a new paleoseismological record of ruptures along the Northern Dead Sea Fault
Hubert, Aurelia ULg; El Ouahabi, Meriam ULg; Lebeau, Hèlène et al

Poster (2014, June 30)

The study focuses on the sedimentary record of the Amik Lake occupying the central part of a pull-apart basin. The Basin is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle ... [more ▼]

The study focuses on the sedimentary record of the Amik Lake occupying the central part of a pull-apart basin. The Basin is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to the East Anatolian Fault Zone in the north. Around the Amik Basin, continuous human occupation is attested since 6000-7000 BC. Indeed the low-lying Amuq plain is covered by tell settlements first explored by Robert Braidwood in the 1930s. Our objective in this presentation is to look at major paleo-environmental changes recorded in the Amik Lake over the last 4000 years and in particular its potential paleoseimic sedimentary record. The lake has been drained and progressively dried up since the mid-50s so that it is not watered during the summer season and constitutes a unique opportunity to collect sediment records. Sediments were collected at 1 cm to 2 cm intervals in a trench and in cores up to a depth of 5 meters in the clay deposits. A diverse array of complementary methods is applied to study the records: magnetic susceptibility, grain size, organic matter and inorganic carbon (L.O.I), XRD mineralogy, XRF geochemistry, carbon geochemistry and clay mineralogy. The age of the record is constrained combining radionuclide and radiocarbon dating. The sedimentary record shows large earthquake related structural disturbances and smaller siliciclastic sedimentary events. The siliciclastic input would be related to enhanced detritical sedimentation related to earthquake shaking. The latter is further investigated looking at intensities and shake maps related to the last 19th century M>7 earthquakes in the area and landslide prone area in the lake catchment. [less ▲]

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See detailPLANTIGRADY DUE TO A LOCALIZED MYOPATHY IN TWO NEWBORN BELGIAN BLUE CALVES
Genart, Marie; Evrard, Laurence ULg; Garcia da Fonseca et al

Poster (2014, June 26)

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See detailL’ancrage dans les herbiers à Posidonia oceanica. Conséquences chimiques de la destruction mécanique ?
Abadie, Arnaud ULg

Poster (2014, June 26)

La plante marine endémique de Méditerranée Posidonia oceanica, ou posidonie, forme en Corse des herbiers colonisant les substrats depuis la surface jusqu’à 40 m de profondeur. Ces herbiers constituent un ... [more ▼]

La plante marine endémique de Méditerranée Posidonia oceanica, ou posidonie, forme en Corse des herbiers colonisant les substrats depuis la surface jusqu’à 40 m de profondeur. Ces herbiers constituent un véritable écosystème, l’un des plus riches en espèces de Méditerranée. Ils jouent un rôle écologique essentiel en oxygénant le milieu grâce à la photosynthèse et en séquestrant du CO2 au sein de leur complexe racinaire dans le sédiment (ou "matte"). Ces activités métaboliques entraînent une importante modification des conditions biogéochimiques du substrat qui favorisent le maintien de la plante. Les herbiers ont également une grande importance économique servant de nurserie pour de nombreuses espèces exploitées par la pêche commerciale et récréative. Les herbiers de posidonie se développant dans les zones côtières, ils sont impactés par les activités anthropiques (urbanisation, pollution, fermes aquacoles, ancrage) qui peuvent entraîner d’importantes destructions et des régressions de leur zone de recouvrement. L’ancrage intensif dans les herbiers à faible profondeur y génère des trouées, ou "intermattes". Les destructions engendrées par les navires de petite taille (< 10 m) peuvent, dans certaines conditions, être recolonisées par la posidonie. Cependant, dans la plupart des zones d’ancrage intensif en Corse, les intermattes ne sont pas recolonisées et leur surface peut souvent augmenter. De plus, certaines zones sont soumises à l’ancrage intensif de navires de plaisance de grande taille (> 20m), susceptibles de générer des intermattes d’une étendue plus importante. Ce phénomène d’expansion ne peut s’expliquer par la seule destruction mécanique. L’arrachage de la strate foliaire de la posidonie par les ancres semble entraîner de profondes modifications physiques et chimiques dans le sédiment. La photosynthèse via les feuilles étant ainsi altérée, il n’y a plus d’oxygénation du sédiment via les racines de la posidonie et un milieu anoxique défavorable à son développement paraît se créer. Des composés toxiques pour la plante, tel que le sulfure d’hydrogène (H2S), pourraient alors s’introduire dans ses tissues entraînant une limitation de son développement, voire sa disparition menant ainsi à une amplification des dégâts mécaniques de l’ancrage. Des observations seront réalisées tout autour de la Corse et notamment dans la Baie de Calvi, site atelier de la Méditerranée, qui a été définie pour mener la phase d’expérimentation. Les données récoltées à l’issue de ces travaux de recherches, réalisés dans le cadre d’un doctorat en entreprise (bourse CIFRE), seront compilées afin de mettre au point de nouveaux outils d’analyse de l’impact de l’ancrage. [less ▲]

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See detailProbing the conformational changes during desolvation of ions using orthogonal mobility methods (CE-IM MS)
Far, Johann ULg; Kune, Christopher ULg; Delvaux, Cédric ULg et al

Poster (2014, June 24)

Routine analyses using Mass Spectrometry (MS) detection became a very popular due to the low limit of detection, great sensitivity, selectivity and specificity. Moreover MS enables structural elucidation ... [more ▼]

Routine analyses using Mass Spectrometry (MS) detection became a very popular due to the low limit of detection, great sensitivity, selectivity and specificity. Moreover MS enables structural elucidation and physical (or physicochemical) properties determination using low amount of not especially pure samples. One of these properties is substantially the stoichiometry determination of non-covalent complexes such as Ligand receptor systems (e.g. DNA-drugs, Hormones/drugs-receptor, quaternary structure arrangement of polypeptides, …). MS determination in native condition (Native MS) of this stoichiometry allows large scale screening of potential drugs candidates in pharmaceutical context. The addition of Ion-Mobility (IM) to mass spectrometry (IM-MS) with computational chemistry support allows the structural conformation monitoring (as Collisional Cross Section or CCS) and the elucidation of interactions of the non-covalent complexes. Nonetheless such determinations suppose/assume that desolvation steps and gas phase transfer during MS detection do not modify the tridimensional structure of these systems or the magnitude order of the involved interactions (dipole-dipole, dipole-ion, ion-ion, hydrophobic interactions). Further studies (Circular Dichroism, Nuclear Magnetic resonance, UV-Visible spectra …) are generally required to confirm the MS data but there are unfortunately time consuming. This project proposes the coupling of Capillary Electrophoresis (CE) to IM-MS in order to obtain in one injection the quantitative and qualitative data of non-covalent complexes and the monitoring of tridimensional conformation modification between the liquid and gas phase. Indeed CE allows the determination of numerous physicochemical properties (dissociation constant, pK values, hydrodynamic radius determination …). The structural data (i.e. hydrodynamic radius and CCS) are compared to the data obtained by IM-MS as a proof of concept using tryptic digest of Bovine Serum Albumine (BSA). [less ▲]

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See detailSymmetric N-qubit anticoherent states
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Poster (2014, June 23)

Entanglement is among the key features of quantum mechanics. In the last decade, a lot of efforts has been made to quantify the amount of entanglement of various multipartite states, either pure or mixed ... [more ▼]

Entanglement is among the key features of quantum mechanics. In the last decade, a lot of efforts has been made to quantify the amount of entanglement of various multipartite states, either pure or mixed. In particular, the search for maximally entangled states (states maximizing certain measures of entanglement) has focused a great deal of attention, see e.g. Refs. [1–4]. In this work, we present a comprehensive study of maximally entangled symmetric N-qubit states with respect to the definition of Gisin [1]. According to this definition, a state is maximally entangled if all its one-qubit reduced density matrices are maximally mixed. These states maximize various entanglement measures, such as von Neumann and Meyer-Wallach entropies [5]. They are unique up to local unitaries within the class of states interconvertible under stochastic local operations and classical communication (SLOCC) [3]. Besides, they are conjectured to be maximally entangled with respect to the Negative Partial Transpose measure of entanglement [6]. As appreciated by B. Kraus, they play an important role in the determination of the local unitary equivalence of multiqubit states [7]. Moreover, they are maximally fragile (in the sense that they are the states which are the most sensitive to noise) and therefore have been proposed as ideal candidates for ultrasensitive sensors [1]. We provide general conditions for a symmetric state with an arbitrary number of qubits to be maximally entangled and identify families of SLOCC classes which do not contain any such states. We also compute various measure of entanglement associated with those states in order to characterize them further and find all maximally entangled states up to 4 qubits. We finally prove that maximally entangled states coincide with anticoherent states of order 1. According to the definition of Ref. [8], a symmetric state of N qubits is anticoherent to order t iff 〈(S·n)k〉 is independent of n for k = 1, . . . , t where n is a tridimensional unit vector and S is the collective spin operator associated to the N-qubit system. [1] N. Gisin, H. Bechmann-Pasquinucci, Phys. Lett. A 246 (1998). [2] A. Higuchi, A. Sudbery, Phys. Lett. A, 272, 213 (2000). [3] F. Verstraete, J. Dehaene, B. De Moor, Phys. Rev. A 68, 012103 (2003). [4] J. Martin, O. Giraud, P. A. Braun, D. Braun and T. Bastin, Phys. Rev. A 81, 062347 (2010). [5] D. A. Meyer, N. R. Wallach, J. Math. Phys. 43, 4273 (2002). [6] I. D. K. Brown, S. Stepney, A. Sudbery, and S. L. Braunstein, J. Phys. A 38, 1119 (2005). [7] B. Kraus, Phys. Rev. Lett. 104, 020504 (2010). [8] J. Zimba, EJTP 3, 10 (2006). [less ▲]

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See detailGeneration of artificial magnetic fields using dipole-dipole interactions
Cesa, Alexandre ULg; Martin, John ULg

Poster (2014, June 23)

In 1996, Lloyd [1] showed that the dynamics of complex many-body quantum systems can be efficiently simulated by quantum computers, an idea first put forward by Manin [2] and further developed by Feynman ... [more ▼]

In 1996, Lloyd [1] showed that the dynamics of complex many-body quantum systems can be efficiently simulated by quantum computers, an idea first put forward by Manin [2] and further developed by Feynman [3]. Although the first quantum computers of a few qubits have been realised experimentally [4, 5], the advent of scalable quantum computers might take another few decades. An alternative tool in the context of simulation is a highly controllable quantum system able to mimic the dynamics of other complex quantum systems, known as an analog quantum simulator. Cold neutral atoms and trapped ions have been shown to be versatile quantum simulators [6, 7] thanks to their high flexibility, controllability, and scalability. They permit one to study a wide range of problems arising from atomic physics, relativistic quantum physics, or cosmology [8]. Since neutral atoms do not carry any net charge, the simulation of electric and magnetic condensed matter phenomena, such as the spin Hall effect, seems out of reach. To overcome this apparent difficulty, the idea has been proposed to create artificial electromagnetic potentials for neutral atoms based on atom-light interaction [9– 12]. These artificial potentials act on neutral atoms as real electromagnetic potentials act on charged particles. Many works on artificial gauge potentials induced by atom-light interactions adopt a single-particle approach [12]. The predicted potentials are then supposed to be valid for a system of weakly interacting atoms. So far, the consequences of atom-atom interactions on the generation of artificial gauge fields has little been studied. The aim of this work is to study the artificial gauge fields arising from the interaction of two Rydberg atoms driven by a common laser field [13]. In this situation, we show that the combined atom-atom and atom-field interactions give rise to nonuniform, artificial gauge potentials. We identify the mechanism responsible for the emergence of these gauge potentials. Analytical expressions for the latter indicate that the strongest artificial magnetic fields are reached in the regime intermediate between the dipole blockade regime and the regime in which the atoms are sufficiently far apart such that atom-light interaction dominates over atom-atom interactions. We discuss the differences and similarities of artificial gauge fields originating from resonant dipole-dipole [14] and van der Waals [15] interactions. We also give an estimation of experimentally attainable artificial magnetic fields resulting from this mechanism and we discuss their detection through the deflection of the atomic motion. [1] S. Lloyd, Science 273, 1073 (1996). [2] Yu. I. Manin, Computable and uncomputable, Sovetskoye Radio, Moscow, 1980. [3] R. P. Feynman, Int. J. Theor. Phys. 21, 467 (1982). [4] L. DiCarlo, J. M. Chow, J. M. Gambetta, Lev S. Bishop, B. R. Johnson, D. I. Schuster, J. Majer, A. Blais, L. Frunzio, S. M. Girvin, and R. J. Schoelkopf, Nature 460, 240 (2009). [5] N. Xu, J. Zhu, D. Lu, X. Zhou, X. Peng, and J. Du, Phys. Rev. Lett. 108, 130501 (2012). [6] I. Buluta and F. Nori, Science 326, 108 (2009). [7] I. Bloch, J. Dalibard and S. Nascimbéne, Nature Physics 8, 267 (2012). [8] R. Blatt and C. F. Roos, Nature Physics 8, 277 (2012). [9] G. Juzeliunas and P. Öhberg, Phys. Rev. Lett. 93, 033602 (2004). [10] G. Juzeliunas, P. Öhberg, J. Ruseckas, and A. Klein, Phys. Rev. A 71, 053614 (2005). [11] G. Juzeliunas, J. Ruseckas, P. Öhberg, and M. Fleischhauer, Phys. Rev. A 73, 025602 (2006). [12] J. Dalibard, F. Gerbier, G. Juzeliu ̄nas, and P. Öhberg, Rev. Mod. Phys. 83, 1523 (2011). [13] A. Cesa and J. Martin, Phys. Rev. A 88,062703 (2013). [14] A. Gaëtan, Y. Miroshnychenko, T. Wilk, A. Chotia, M. Viteau, D. Comparat, P. Pillet, A. Browaeys, and P. Grangier, Nature Physics 5, 115 (2009). [15] L. Béguin, A. Vernier, R. Chicireanu, T. Lahaye, and A. Browaeys, Phys. Rev. Lett. 110, 263201 (2013). [less ▲]

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See detailChemical abundances of fast-rotating OB stars
Cazorla, Constantin ULg; Morel, Thierry ULg; Nazé, Yaël ULg et al

Poster (2014, June 23)

Fast rotation in massive stars is predicted to induce mixing in their interior, but recent observations have challenged this concept by revealing a population of fast-rotating stars with normal nitrogen ... [more ▼]

Fast rotation in massive stars is predicted to induce mixing in their interior, but recent observations have challenged this concept by revealing a population of fast-rotating stars with normal nitrogen abundances at their surface (Hunter et al. 2009, A&A, 496, 841; Brott et al. 2011, A&A, 530, A116, but see Maeder et al. 2014, A&A, 565, A39). However, as the binary fraction of these stars is unknown, the importance of mass-transfer processes cannot be quantified. As a result, no definitive statements about the ability of single-star evolutionary models including rotation to reproduce these observations can be made. Our work combines for the first time a detailed surface abundance analysis with a radial-velocity monitoring for a sample of bright, fast-rotating Galactic OB stars to put strong constraints on stellar evolutionary and interior models. [less ▲]

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See detailEvaluation of SFC interest for the determination of cholecalciferol and its impurities un pharmaceuticals
Andri, Bertyl ULg; Dispas, Amandine ULg; Klinkenberg, Régis et al

Poster (2014, June 23)

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See detailAlteration of decoherence-free states caused by dipole-dipole interactions
Damanet, François ULg; Martin, John ULg

Poster (2014, June 23)

Decoherence, known as the consequence of the coupling of any quantum system to its environment, causes information loss in the system and represents a major problem in the physical realization of quantum ... [more ▼]

Decoherence, known as the consequence of the coupling of any quantum system to its environment, causes information loss in the system and represents a major problem in the physical realization of quantum computers [1]. Decoherence-Free States (DFS) are considered as a possible solution to this problem. A set of trapped cold atoms placed in a DFS state will be immune against decoherence due to spontaneous emission. However, because of dipole-dipole interactions between atoms, induced dephasing effects are likely to destroy the coherence and drive the system out of its DFS [1, 2]. In this work, we study numerically the dynamics of a set of two-level atoms initially in a DFS with respect to dissipative processes by solving the master equation including both dissipative dynamics and dipole dipole interactions. We fo- cus our attention on the infuence of dipolar coupling on the radiated energy rate and coherence of the system as in [3]. In particular, by averaging over many realizations of close randomly distributed atomic positions, we show the formation of a superradiant-like pulse and we study its properties as a function of the dipolar coupling strength. [1] D. A. Lidar & K. B. Whaley, Lectures Notes in Phys., Vol. 622, p83-120, Springer (2003). [2] M. Gross & S. Haroche, Physics reports 93, 301-396 (1982). [3] W. Feng, Y. Li & S-Y. Zhu, Phys. Rev. A 88, 033856 (2013). [less ▲]

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See detailContribution of ion mobility for structural analysis and analytical chemistry: Use of selective IMS shift reagents (SSR)
Kune, Christopher ULg; Far, Johann ULg; Delvaux, Cédric ULg et al

Poster (2014, June 19)

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the ... [more ▼]

Ion mobility is a gas phase separation technique based on the Collisional Cross Section (CCS) of ions. It discriminates isobaric and isomeric ions provided their CCS difference is larger than the instrumental resolution. This work proposes a new method to overcome this limitation while providing additional structural information. A Selective Shift Reagent (SSR) is a ligand specifically modifying the CCS of ions. Indeed specific non-covalent complexes can be form with a suitable SSR to reach the required selectivity and the CCS induced shift. A CID dissociation of the complex may be used after IMS separation to produce specific MS/MS spectra of the targeted analyte. This concept paves the way for new analytical strategies by ion mobility based on non-covalent complex formation. [less ▲]

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See detailLes univers vidéoludiques : des fictions mobiles et jouables
Barnabé, Fanny ULg

Poster (2014, June 18)

La question de la fiction constitue, depuis le début des années 2000, une clef d’entrée privilégiée pour étudier le médium vidéoludique. La capacité du jeu vidéo à prendre en charge la représentation ... [more ▼]

La question de la fiction constitue, depuis le début des années 2000, une clef d’entrée privilégiée pour étudier le médium vidéoludique. La capacité du jeu vidéo à prendre en charge la représentation d’une histoire par ses propres moyens (et non en empruntant ceux de la littérature ou du cinéma) a été tantôt affirmée (Ryan, 2003 ; Murray, 1998), tantôt contestée (Frasca, 1999 ; Juul, 2001 ; Eskelinen, 2001). Dès lors – même si les oppositions à son sujet sont aujourd’hui plus nuancées – elle demeure un objet problématique dont le traitement entraîne souvent d’importants détours théoriques. Les concepts de la narratologie « traditionnelle » (tels que celui d’un récit clos et prédéfini ou d’une narration « unidirectionnelle ») semblent a priori peu compatibles avec les impératifs d’interaction et de jouabilité qui sont au cœur de l’expérience vidéoludique. Quels outils adopter, en conséquence, pour décrire ce qui advient de la fiction lorsqu’elle est prise en charge par le jeu ? C’est à cette question que nous tâcherons de répondre en définissant les contours d’une notion souvent évoquée par la recherche, mais peu théorisée : celle d’« univers fictionnel ». Pour ce faire, nous nous nourrirons tant des avancées des games studies et des « play studies » (Triclot, 2011) que des théories de la fiction (Schaeffer, 1999) et de ses modes actuels de consommation par les amateurs (Jenkins, 2006). La distinction opérée par Amato (2005) entre les notions de cosmos, de diégèse et de ludiégèse permettra également de préciser la définition de ce qu’est un univers lorsqu’il est régi par le jeu. En effet, la narrativité propre au jeu vidéo ne semble pas répondre à la logique linéaire du récit : une grande part de l’histoire n’est généralement présente que de manière « latente » (Letourneux, 2005) dans une série d’éléments hétérogènes (le texte, l’interface, les décors, les sons, les objets…), situés à différents niveaux de l’œuvre et dont le sens narratif peut ou non être activé par le joueur (Guardiola, 2005 parle, à ce titre, de la dimension « permissive » du jeu vidéo). Pour décrire cette pluri-dimensionnalité et cette dispersion de l’histoire au sein d’« éléments de narrativisation » (Genvo, 2002), la notion de récit apparaît comme réductrice. À l’inverse, celle d’univers (définie dès lors comme un agencement d’éléments non hiérarchisés et éventuellement porteurs d’une narrativité latente) présente une forte opérationnalité, due principalement à deux de ses caractéristiques : son ouverture et sa nature modulable. Son ouverture, tout d’abord, car elle permet non seulement de prendre en compte l’ensemble des composantes de la fiction qui sont internes à l’œuvre vidéoludique, mais aussi celles qui lui sont externes (qu’il s’agisse du paratexte, des livrets des jeux, des bandes annonces,… ou encore de véritables développements narratifs autonomes, réalisés sur différents médias). Sa malléabilité, ensuite, car le concept d’univers, contrairement à celui de narration, admet l’interactivité : c’est le joueur qui actualise le récit (il participe à son énonciation) et qui, par la continuité de sa présence, organise les « éléments de narrativisation » en une configuration cohérente. En outre, concevoir la fiction comme un agencement de diverses composantes permet d’envisager les constantes évolutions que lui font subir les communautés d’amateurs : ceux-ci, en confrontant leurs représentations, développent par exemple des modèles collectifs « non officiels » (les « fanons » ; voir Hellekson et Busse, 2006) qui ont un impact certain sur la vie des fictions. L’univers fictionnel constitue, en somme, un outil théorique porteur qui rend possible la description des points de passage entre jeu et fiction et l’évaluation des contraintes que l’un exerce sur l’autre. Toutefois, bien qu’il ait initialement été élaboré pour correspondre au domaine spécifique du jeu vidéo, le concept semble déborder de ces premiers questionnements et s’adapter, plus généralement, à l’étude des modes actuels de production et de consommation de la fiction. En effet, son ouverture invite, d’une part, à élargir la conception traditionnelle de la narration et à l’envisager comme un ensemble transmédiatique. D’autre part, sa nature d’agencement n’est pas sans rappeler les théories d’Azuma (2008) selon lesquelles les fictions postmodernes ne sont plus considérées comme des unités finies et fermées, mais comme des agencements qui puisent dans un fonds commun, une « base de données » perpétuellement renouvelée. Chaque élément investi par la fiction intègre ce fonds commun et devient alors susceptible de connaître des continuations, des réappropriations, des réagencements. Les histoires conçues sur ce mode ne sont pas lues, mais vécues et explorées : la lecture devient une expérience et une expérimentation. [less ▲]

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See detailPolyester-based microcarriers with enhanced surface properties for tissue engineering
Markvicheva, Elena; Privalova, Anna; Sevrin, Chantal ULg et al

Poster (2014, June 17)

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See detailIN VITRO STUDY OF A FIBER NETWORK TAILORED AS 3D-CELL MODEL
Sevrin, Chantal ULg; Lombart, François ULg; Godino, Miguel et al

Poster (2014, June 17)

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See detailA forward genetic screen to identify hydrogenase-deficient mutants in the unicellular green alga Chlamydomonas reinhardtii
Emonds-Alt, Barbara ULg; Godaux, Damien ULg; Cardol, Pierre ULg et al

Poster (2014, June 15)

The ability of the unicellular green alga Chlamydomonas reinhardtii to evolve molecular hydrogen (H2) is due to the presence of oxygen-sensitive Fe-hydrogenases (HydA1/2), expressed in anoxic conditions ... [more ▼]

The ability of the unicellular green alga Chlamydomonas reinhardtii to evolve molecular hydrogen (H2) is due to the presence of oxygen-sensitive Fe-hydrogenases (HydA1/2), expressed in anoxic conditions that drive the photosynthetic electron flow to reduce protons into H2. In order to identify new players involved in H2 photoproduction in Chlamydomonas, an insertion mutant library was generated using cassettes conferring resistance to hygromycin or paromomycin. Hydrogenase activity is physiologically relevant during a transition from dark anoxia to light. In dark anoxic conditions, the cellular redox poise is high and the photosynthetic electron transport chain is fully reduced. Upon illumination, hydrogenase activity allows the reoxidation of photosynthetic intersystem electron carriers until oxic conditions and carbon fixation ability are restored. We thus designed an in vivo fluorescence imaging screen based on the different kinetics of photosynthesis induction between wild type and hydrogenase-deficient mutants [1]. At this stage, three putative hydrogenase mutants have been identified on 10,000 transformants. Molecular characterization of the insertion site of the resistance cassette by TAIL-PCR and genetic analyses of the linkage between the antibiotic resistance and the fluorescence phenotype showed that one mutant was untagged with the resistance while two tagged mutants were deficient for the HydG assembly factor. [less ▲]

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See detailDétermination de la teneur en équol dans les laits commercialisés en Wallonie (Belgique)
Daems, Frédéric ULg; Jasselette, Christophe; Franckson, Delphine et al

Poster (2014, June 13)

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See detailTrouble de la reconnaissance de soi chez des personnes atteintes de la maladie d'Alzheimer
Moyse, Evelyne ULg; Bastin, Christine ULg; Salmon, Eric ULg et al

Poster (2014, June 12)

Introduction : Outre des difficultés de mémoire épisodique, la maladie d’Alzheimer est associée à une altération progressive du fonctionnement de la mémoire sémantique où les connaissances du passé ... [more ▼]

Introduction : Outre des difficultés de mémoire épisodique, la maladie d’Alzheimer est associée à une altération progressive du fonctionnement de la mémoire sémantique où les connaissances du passé lointain sont mieux préservées que les connaissances acquises récemment. De plus, il a été rapporté que ce type de perte peut aussi se produire pour la reconnaissance de son propre visage. Une étude décrivait le cas d’une femme atteinte de la maladie d’Alzheimer à un stade avancé qui était incapable de se reconnaître sur des photographies prises dans un passé récent mais qui avait peu voire pas de difficultés à se reconnaître sur des photographies prises pendant les deux premières décennies de sa vie adulte. Cependant, la description d’une seule étude de cas pourrait être vue comme anecdotique. Objectifs : L’objectif de cette étude est d’évaluer si ce type de difficultés peut s’observer dans un plus large échantillon de patients. Pour ce faire, des patients à des stades légers à modérés de la maladie sont comparés à des sujets âgés sains sur une tâche de reconnaissance de visages (soi, familier, inconnu) appartenant à différentes périodes de vie (20 ans jusqu’à récemment). Résultats : Au stade léger, les patients présentaient des difficultés uniquement pour reconnaître le visage d’une personne familière alors qu’au stade modéré de la maladie, ces difficultés s’observaient à la fois pour le visage familier et le propre visage. De plus, comparés aux sujets âgés sains, les patients modérés avaient des difficultés pour se reconnaître sur des photos récentes, alors qu’aucune différence n’était observée pour les autres périodes de vie. Par contre, aucune différence entre les patients légers et leurs sujets contrôles n’était observée selon l’âge des visages. Par ailleurs, l’analyse des temps de réaction montraient que ces deux groupes de participants étaient plus lents pour reconnaître les photos anciennes par rapport aux photos récentes. Conclusion : La présente étude révèle que les difficultés de reconnaissance des visages évoluent avec l’avancement de la maladie, avec des difficultés qui touchent uniquement la reconnaissance de visages familiers au stade léger de la maladie mais qui s’étendent au propre visage au stade modéré. De plus, une perte graduée dans le temps de la reconnaissance de soi est observée chez les patients modérés (moindre reconnaissance de son visage récent) mais pas chez les patients légers. Au contraire, un ralentissement de la reconnaissance des photos anciennes par rapport aux photos récentes était constaté chez les patients légers ainsi que chez leurs sujets contrôles. Deux hypothèses sont avancées pour expliquer ce phénomène. Premièrement, les photos anciennes provoqueraient une réaction de surprise et par là, augmenteraient le temps de réponse. La seconde hypothèse postule plutôt une difficulté d’accès aux représentations antérieures de soi et de son proche. [less ▲]

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See detailGround-based transmission spectrum of WASP-80 b, a gas giant transiting an M-dwarf
Delrez, Laetitia ULg; Gillon, Michaël ULg; Lendl, Monika ULg et al

Poster (2014, June 09)

We present here some results from our ground-­based multi-­object spectroscopy program aiming to measure the transmission spectrum of the transiting hot Jupiter WASP-80b using the VLT/FORS2 instrument ... [more ▼]

We present here some results from our ground-­based multi-­object spectroscopy program aiming to measure the transmission spectrum of the transiting hot Jupiter WASP-80b using the VLT/FORS2 instrument. WASP-­80b is a unique object as it is the only known specimen of gas giant orbiting an M-dwarf that is bright enough for high SNR follow-­up measurements. Due to the nature of its host star, this hot Jupiter is actually more `warm' than `hot', with an estimated equilibrium temperature of only 800K. It is thus a prime target to improve our understanding of giant exoplanet atmospheres in this temperature range. [less ▲]

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See detailEffects of tillage practices and crop residue exportation on earthworm communities and soil physico-­chemical properties in silt loam arable soil (Belgium)
Lemtiri, Aboulkacem ULg; Colinet, Gilles ULg; Alabi, Taofic ULg et al

Poster (2014, June 08)

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological ... [more ▼]

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers due to their capacity to influence a wide range of chemical, physical, and biological properties of soil environments. Therefore, it is important to understand how earthworm communities are impacted by tillage systems and crop management practices. In the present study, earthworm and soil samples were collected from wheat cultivated fields in Gembloux, Belgium under the following four experimental treatments: (1) conventional tillage with crop residues left in the soil (CT/IN); (2) conventional tillage with crop residues removed from the field (CT/OUT); (3) reduced tillage with crop residues left in the soil (RT/IN); and (4) reduced tillage with crop residues removed from the field (RT/OUT). The different tillage systems were applied for four consecutive years prior to the initiation of the current study. Results indicated soil compaction was significantly higher in RT compared with CT up to a depth of 6–49 cm. Significant differences were not detected between residue incorporation depth systems, where results showed mean earthworm abundance was respectively 182.25 and 180 individuals.m-2 in CT and RT. Mean earthworm biomass was similarly not significantly different between CT and RT, where results were respectively 48.52 and 57.27 g.m-2. However, a significant difference was observed between IN and OUT treatments, suggesting the exportation of wheat residues will limit earthworm abundance and biomass in CT and RT plots. Data showed high representation of the endogeic earthworm ecological category, notably N. c. caliginosus regardless of treatment. Despite tillage system and exportation of crop residues, N. c. caliginosus, L. terrestris, and A. r. rosea exhibited high abundance, indicating tolerance to soil environmental conditions. For each depth, measures of soil physico-chemical properties showed significant differences among treatments. Furthermore, soil chemical property attributes were significantly higher in the first soil centimetres compared to lower soil layers. These results were attributable to earthworm activity and wheat residues, suggesting earthworms contributed to nutrient dynamics, particularly at increased soil depths. Overall, the results emphasise the influence of exportation of crop residues on earthworm community and also, the important influence of earthworm activity on soil physico-chemical properties change, processes which are closely linked. [less ▲]

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See detailComparison between wind speed observed at 100m height and wind speeds simulated by the WRF and MAR models
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg et al

Poster (2014, June 06)

In the context of FLEXIPAC project funded by "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology and Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the ... [more ▼]

In the context of FLEXIPAC project funded by "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology and Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the WRF regional model (v.3.4.) forced by ERA-Interim model. Our analysis shows that wind speeds at 100m height simulated by WRF are systematically overestimated compared to wind speeds extracted from wind productions of two wind farms. In order to identify this problem, four comparisons were performed in this contribution. Firstly, we compare WRF model with reanalysis based forcing model. Secondly, we compare two WRF simulations, where one of them has a more precise spatial resolution. Thirdly, we smooth WRF outputs in time (6-hr running mean) in order to study the accuracy of the 30-min variability generated by WRF model. Finally, we comp compare the WRF model with the MAR (v3.3.) regional model using the same forcing at its lateral boundaries. This last one seems to suggest that the MAR model better simulates wind speeds at 10m and at 100m than WRF model and then that wind speed underestimation by WRF is well linked to the WRF physics itself. [less ▲]

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See detail[18F]UCB-H AS A NEW PET RADIOTRACER FOR SYNAPTIC VESICLE PROTEIN 2A
Bahri, Mohamed Ali ULg; Bastin, Christine ULg; Aerts, Joël ULg et al

Poster (2014, June 06)

Synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown ... [more ▼]

Synaptic vesicle protein 2A (SV2A) is widely distributed in the brain and has been demonstrated to be involved in vesicle trafficking. The critical role of SV2A in proper nervous system function is shown, for example, by the fact that it is a binding site and the primary mechanism of levetiracetam. Levetiracetam is an antiepileptic drug which has recently been suggested to reduce synaptic deficits in a mouse model for Alzheimer’s disease and to improve cognition in patients with amnestic mild cognitive impairment. We here aimed to investigate the cerebral distribution of [18F]UCB-H, a fluorine-18 radiolabelled PET imaging tracer, which has a high affinity with the SV2A. [18F]UCB-H was radiosynthesized under GMP conditions. Dynamic PET data of the head of four healthy volunteers were acquired over 100 minutes after injection of 170.4 ± 24.9 MBq of [18F]UCB-H. The arterial input function was obtained by blood sampling during the dynamic PET acquisition. The analysis of the blood data reveled a consistent amount of [18F]UCB-H in whole blood and plasma which indicates a very low degree of binding of the tracer to the red blood cells. The unchanged fraction of [18F]UCB-H in plasma showed a bi-exponential behavioral decrease with a starting fraction of 92% of the injected amount of the tracer, measured at 3 min post injection. This fraction decreased to about 50% at 10 min post injection. The [18F]UCB-H PET data showed a high and rapid uptake in the grey matter structures, matching the known ubiquitous distribution of the SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout allowing the standard compartmental modeling (1-tissue compartment, 2-tissue compartment, and Logan graphical analysis). The three models gave consistent results. The two-tissue compartment model fitted the experimental data best and provided a total distribution volume of the [18F]UCB-H in the brain greater than 7 mL/cm3 and a specific distribution volume around 3 mL/cm3. Our results suggest that [18F]UCB-H is a good candidate as radiotracer for brain SV2A proteins and could be used for human studies. In the future, SV2A modifications might be assessed in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detailA PREFERENTIAL FOLDED CONFORMATION OF SOME BIS-(8-ISOPROPYL-ISOQUINOLINIUM) DERIVATIVES EXPLAINS STEREOSELECTIVE REDUCTION BY SODIUM BOROHYDRIDE
Dilly, Sébastien ULg; Badarau, Eduard; Dufour, Fabien et al

Poster (2014, June 05)

Small conductance Ca2+-activated K+ (SK) channels play a role in modulating the firing rate and the firing pattern of neurons [Waroux, Eur J Neurosci, 2005, 22, 3111]. A blockade of these targets could be ... [more ▼]

Small conductance Ca2+-activated K+ (SK) channels play a role in modulating the firing rate and the firing pattern of neurons [Waroux, Eur J Neurosci, 2005, 22, 3111]. A blockade of these targets could be useful for the treatment of cognitive dysfunction, neuronal hyperexcitability or dopamine related disorders [Liégeois, Curr Med Chem, 2003, 10, 625]. At the peripheral level, the inhibition of these channels was demonstrated to prevent and terminate atrial fibrillation [Diness, Circ Arrhythm Electrophysiol, 2010, 3, 380]. Moreover, SK channels might represent potential targets for a new class of anticancer agents due to their involvement in breast cancer cell migration [Potier, Mol Cancer Ther, 2006, 5, 2946]. So far, available blockers are not suitable CNS pharmacological tools being either peptides or small molecules with permanent positive charges [Liégeois, Curr Med Chem, 2003, 10, 625; Graulich, J Med Chem, 2007, 50, 5070; Badarau, Bioorg Med Chem Lett, 2011, 21, 6756]. Therefore, symmetrical bis-isoquinolinium compounds have subsequently been transformed to 1,2,3,4-tetrahydroisoquinoline analogues by using sodium borohydride leading to a diastereoisomeric mixture (figure 1) in order to obtain potential CNS-penetrating agents [Graulich, Bioorg Med Chem Lett, 2008, 18, 3440; Neny, Proceedings of the 12th International Conference on In Vivo Methods, Vancouver, Canada, 2008, 267; Koulchitsky, Acta Physiologica, 2009, 195, 670]. Resolution of these mixtures and characterization of the corresponding stereoisomers [Wouters, Eur J Med Chem, 2010, 45, 3240] are necessary before further biological evaluation. In a series of 8- isopropyl analogues, chiral resolution failed for the analogues with propyl and m-xylyl linkers since two and one peaks, respectively, were detected [Nistor, J Pharm Biomed Anal, 2013, 74, 273]. Could these results be explained by an ineffective resolution or would another phenomenon be involved? Further analysis using chiral chromatography, mass spectroscopy and circular dichroism of a sample of the propyl analogue revealed that it is a racemic mixture. X-ray cristallography and conformational analysis indicated a folded conformation of the propyl and m-xylyl analogues (figure 2) responsible for a stereoselective attack of the borohydride reagent during the reduction step. Additional 1H-NMR investigations support structural features detected by theoretical analysis. [less ▲]

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See detailApproche lexicométrique des controverses climatiques
Scotto d'Apollonia, Lionel; Luxardo, Giancarlo; Piet, Grégory ULg

Poster (2014, June 05)

D’un point de vue historique, les controverses climatiques prennent racine à la fin du XIXe siècle et se sont déployées tout au long du XXe siècle. Elles prennent toutefois une tournure plus politique, en ... [more ▼]

D’un point de vue historique, les controverses climatiques prennent racine à la fin du XIXe siècle et se sont déployées tout au long du XXe siècle. Elles prennent toutefois une tournure plus politique, en ce début de XXIe siècle, en ce sens que le débat climatique « se priorise » dans les agendas politiques des Etats européens, de manière générale. Si les études sur les controverses climatiques tendent, certes, à se développer de plus en plus actuellement, l’approche linguistique demeure peu investie par rapport au potentiel analytique qu’elle pourrait apporter à la recherche sur le sujet. L’une des rares études lexicométriques concernant le climat est celle réalisée par Lamria Chetouani dont le corpus de textes s’étend de 1989 à 1990. Il faut aussi prendre en compte les travaux de Francis Chateauraynaud, qui a entrepris une démarche destinée au traitement des controverses s'appuyant sur un ensemble de techniques : la socio-informatique. Inscrit dans un cadre d’analyse socioépistémique des controverses socioscientifiques et en se basant sur un corpus de textes choisis autour de la période 2009 - 2010, notre article propose donc d'associer une analyse socio-informatique des controverses climatiques avec une utilisation d'outils lexicométriques. En nous concentrant sur le traitement discursif de quelques notions-clés, notamment l'incertitude et le risque, nous cherchons à croiser les résultats fournis par la lexicométrie (logiciel Lexico) avec ceux fournis par la socio-informatique (logiciel Prospero). En conclusion, nous ouvrons un espace de discussion sur les modes opératoires permettant d'articuler les deux approches. [less ▲]

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See detailLIGAND-INDEPENDENT IDENTIFICATION OF ORPHAN GPCR ARRESTIN BINDING
Dupuis, Nadine ULg; Gilissen, Julie ULg; Derj, Anouar ULg et al

Poster (2014, June 05)

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See detailFunctional study of the Ser/Arg-rich splicing factor SRSF5a during zebrafish embryonic development
Joris, Marine ULg; Muller, Marc ULg; Motte, Patrick ULg

Poster (2014, June 05)

Nuclear pre-mRNA splicing is a key process regulating gene expression in eukaryotes. Splicing consists in the removal of introns and the joining of exons within a dynamic macromolecular complex called the ... [more ▼]

Nuclear pre-mRNA splicing is a key process regulating gene expression in eukaryotes. Splicing consists in the removal of introns and the joining of exons within a dynamic macromolecular complex called the spliceosome, which consist of five small nuclear ribonucleoproteins (snRNPs) and numerous non snRNPs proteins (1). Amongst these non snRNPs proteins, the SR proteins family constituted an important group of splicing factors that are involved in constitutive and alternative splicing (2,3). SR proteins are structurally related as they are characterized by one or two RNA-recognition motifs (RRMs) in N-ter and a C-terminal domain enriched in dipeptide Ser/Arg. Phylogenetic inference using the RRM domain allowed us to identify 13 encoding genes for SR proteins in the vertebrate model organism, Danio rerio. The Zebrafish is increasingly recognized as a powerful model for the study of vertebrate embryonic development in a physiological context. The roles of SR splicing factors during animal cell differentiation and development are largely unknown. The aim of the present research is to investigate SR proteins functions during zebrafish development by using molecular and genetic approaches. In this study, we investigated the role of the SR splicing factor SRSF5a. The expression profile was determined by in situ hybridization at 24, 48 and 72 hours post-fertilization and showed SRSF5a expression mainly in brain, retina and pharyngeal arches at these stages. Furthermore, SRSF5a knock-down by morpholinos microinjection strongly suggests an important role of this specific splicing factor during eyes and brain development. In order to gain insight into the molecular function of SRSF5a, we analysed control and morphant transcriptomes using high throughput RNA sequencing. Finally, we use a complementary approach to morpholinos and generate SRSF5a mutant fishes using TALENs (Tal effector nucleases)(4,5). 1. Wahl MC, Will CL, & Luhrmann R (2009) The spliceosome: design principles of a dynamic RNP machine. Cell 136(4):701-718. 2. Long JC & Caceres JF (2009) The SR protein family of splicing factors: master regulators of gene expression. Biochem J 417(1):15-27. 3. Graveley BR (2000) Sorting out the complexity of SR protein functions. RNA 6(9):1197-1211. 4. Moore et al. (2012) Improved Somatic Mutagenesis in Zebrafish Using Transcription Activator-Like Effector Nucleases (TALENs). Plos One 120(1):1-12. 5. Cade et al (2012) Highly efficient generation of heritable zebrafish gene mutations using homo- and heterodimeric TALENs. Nucleic acid research Vol 40, No 16:8001-8010. [less ▲]

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See detailDesign and synthesis of high-affinity ligands of AMPA receptors and study of their Fluorine-18 radiolabeling
Deverdenne, François ULg; Goffin, Eric ULg; Plenevaux, Alain ULg et al

Poster (2014, June 05)

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

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

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See detailRelations between negative symptomatology and executive measures in schizophrenia.
Laloyaux, Julien ULg; Guettafi, Yassine; Dessart, Gregory et al

Poster (2014, June 03)

Introduction: Negative symptomatology and cognitive impairments are core features of persons diagnosed with schizophrenia that have a major negative impact on everyday life functioning. Further, some ... [more ▼]

Introduction: Negative symptomatology and cognitive impairments are core features of persons diagnosed with schizophrenia that have a major negative impact on everyday life functioning. Further, some authors (Konstantakopoulos et al., 2011) have suggested that negative symptoms and executive functions might represent different manifestations of the same syndrome, but this relation remains poorly understood. Objective: The objective was to explore relations between negative symptomatology (and in particular apathy) and executive functions in persons diagnosed with schizophrenia. Method: Twenty-seven individuals diagnosed with schizophrenia were evaluated with an extensive executive battery in addition to several measures of negative symptomatology (including specific measures of apathy) and real world functioning. Results: Results revealed that apathy was significantly related to measures of initiation (i.e. verbal fluency) and everyday life functioning. Moreover, more general measures of negative symptomatology were significantly related to multitasking abilities and cognitive flexibility. Discussion: In this study, we assessed the relations between negative symptomatology and executive measures. The results confirmed the links between these constructs, thus suggesting a common neural substrate. Conclusion: Based on results from the present study, executive dysfunctions and negative symptomatology may be seen as representing different manifestations of the same syndrome. [less ▲]

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See detailComparison of Indicators to Evaluate the Resilience of Lab Scale Continuously Stirred Anaerobic Reactors Submitted to Biological Dysfunctions
Lemaigre, Sébastien; Adam, Gilles ULg; Goux, Xavier et al

Poster (2014, June 02)

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See detailApplication of hyperspectral Raman imaging to the analysis of a self-emulsifying drug delivery system (SEDDS).
Sacre, Pierre-Yves ULg; De Bleye, Charlotte ULg; Netchacovitch, Lauranne ULg et al

Poster (2014, June)

Self-emulsifying drug delivery systems (SEDDS) are mixtures of drug and excipients that undergo emulsification when exposed to water. This pharmaceutical form is used to enhance the oral absorption of ... [more ▼]

Self-emulsifying drug delivery systems (SEDDS) are mixtures of drug and excipients that undergo emulsification when exposed to water. This pharmaceutical form is used to enhance the oral absorption of poorly water-soluble drugs. The API is finely dispersed in the excipients and forms a solid solution increasing its dissolution rate. Hyperspectral Raman imaging is a powerful tool that combines both spectral and spatial information. It returns qualitative and quantitative information useful during the development or the characterization of pharmaceutical preparations. The studied formulation consisted of a BCS 2 API (high permeability, low solubility) dispersed in excipients mainly composed of Lauroyl macrogol-32 glycerides (>50%). Two different preparations were analyzed: 100% of API dissolved and 70% of API dissolved with 30% of API powder added to the formulation. The two formulations have therefore exactly the same qualitative and quantitative composition but different spatial distribution and dispersion of the API mimicking a problem during the process. First a confocal Raman microscopic analysis was performed to evaluate the solid state of the API in the formulations. Then, an evaluation of the particle size was performed. These results are important since they can affect the bioavailability of the API and therefore its activity. Beside the microscopic scale analysis, a macroscopic imaging quantitative PLS model has been developed. The method has been validated within +/- 10% acceptance limits following the total error approach. This validated quantitative model enables reliable quantitative analysis at the pixel level of Raman images providing meaningful chemical images. [less ▲]

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See detailETEROGENEITÀ GENETICA DI NOROVIRUS BOVINI IDENTIFICATI IN ITALIA
Di Felice, Eliabetta; Di Profio, Federica; Melegari, Irene et al

Poster (2014, June)

I norovirus (NoV) sono piccoli virus a RNA monocatenario appartenenti alla famiglia Caliciviridae. Sulla base dell’analisi di sequenza del gene ORF2 codificante per la proteina capsidica VP1, i NoV sono ... [more ▼]

I norovirus (NoV) sono piccoli virus a RNA monocatenario appartenenti alla famiglia Caliciviridae. Sulla base dell’analisi di sequenza del gene ORF2 codificante per la proteina capsidica VP1, i NoV sono attualmente classificati in sei genogruppi (G), con GI, GII e GIV responsabili di gastroenterite nell’uomo. Calicivirus enterici morfologicamente simili a NoV umani sono stati identificati per la prima volta in vitelli diarroici nel Regno Unito nel 1978 e in Germania nel 1980. Il sequenziamento nucleotidico dell’intero genoma ha permesso di classificare i NoV bovini (BoNoV) all’interno del genogruppo III in due genotipi, GIII.1 (prototipo Bo/Jena/80/DE) e GIII.2 (prototipo Bo/Newbury/76/UK). I BoNoV hanno una diffusione mondiale con una maggiore prevalenza di virus GIII.2-like. Tuttavia, studi recenti basati sull’analisi nucleotidica a livello della giunzione fra la polimerasi (RdRp) ed il capside, hanno dimostrato la circolazione di ceppi ricombinanti. Nel presente lavoro vengono riportati i risultati di un’indagine per la ricerca e tipizzazione di BoNoV condotta su quattro allevamenti bovini ubicati nelle province di Teramo e Pescara. A tal fine, 104 tamponi rettali collezionati da vitelli asintomatici sono stati sottoposti a nested RT-PCR impiegando due set di primer specifici per BoNoV in grado di amplificare un frammento di 326 bp della RdRp. L’RNA di BoNoV è stato identificato nel 10,5% (11/104) degli animali testati. L'analisi di sequenza ha evidenziato per nove sequenze un’elevata identità nucleotidica (nt) (88-96%) con i ceppi GIII.2-like, mentre per due è stata rilevata la maggiore identità (87-90% nt) con i BoNoV GIII.1-like. Per sette ceppi è stata ottenuta anche una sequenza di circa 750 bp che includeva oltre che la regione parziale della RdRp, la regione 5’ capsidica. Sulla base dell’analisi molecolare, cinque ceppi sono risultati strettamente correlati con BoNoV GIII.2-like, mentre solo uno dei due ceppi con polimerasi GIII.1-like, ha mostrato la maggiore identità nucleotidica nei confronti di BoNoV appartenenti al genotipo 1. Il ceppo 80/TE/IT che possedeva una polimerasi GIII.1-like, a livello capsidico ha mostrato la più alta identità con ceppi GIII.2-like, suggerendo un fenomeno di ricombinazione a livello della giunzione ORF1/ORF2. [less ▲]

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See detailInhibition of PDH Kinase as a new therapeutic target for Age-related Macular Degeneration (AMD)
Arslan, Deniz ULg; Pirotte, Bernard ULg; De Tullio, Pascal ULg et al

Poster (2014, June)

Metabolomics is one of the most recent technologies in the world of Omics sciences. It aims at studying metabolome, which is composed of small molecular weight organic molecules (called metabolites) of a ... [more ▼]

Metabolomics is one of the most recent technologies in the world of Omics sciences. It aims at studying metabolome, which is composed of small molecular weight organic molecules (called metabolites) of a cell, an organism or a biological system. This approach gives rise to a growing number of applications in many areas, such as biomarkers discovery, clinical studies, drug efficacy and toxicity evaluation, diagnostic tools, quality control. One of the most interesting features of metabolomics is its capability to extract biochemical information reflecting biological events and then to be a powerful tool in the knowledge of the aetiology of some pathologies. Indeed, it is clear that every disease could alter more or less drastically the metabolic profile of the patients. Then a metabolomics approach could highlight the biochemical pathways affected and could allow the identification of new putative therapeutic strategies or targets that could be useful in a new drug discovery strategy. As proteomics, metabolomics approach represents a new and powerful tool for Medicinal Chemistry. Age-related Macular Degeneration (AMD) is a leading cause of vision loss in the western world among people aged 50 or older. 90% of all vision loss due to AMD results from the exudative form, which is characterized by choroidal neovascularization (CNV). Age-related changes that induce pathologic CNV are incompletely understood. A successful application of anti-VEGF approaches in the clinic is obviously a turning point in AMD treatment. Nevertheless, despite such important advances, critical issues remain to be addressed. To better understand the aetiology of this pathology, we used and improved a murine model of laser-induced choroidal neovascularization and applied a 1H NMR metabolomics study. This approach leads to the emergence of different putative biomarkers and to the validation of the CNV model for an experimental study of AMD. Among these “biomarkers”, lactate appears to be clearly involved in the development of AMD. The modulation of their plasma concentration by treatment of the animals with synthetic compounds and more specifically Pyruvate DesHydrogenase Kinase inhibitors (PDHK) significantly decrease the impact of laser induced CNV. Starting from these results, the development of new PDHK inhibitors could open the way to innovative treatment opportunities in AMD disease. [less ▲]

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See detailBelowground Chemical Ecology: The Case of Wireworms
Barsics, Fanny ULg; Delory, Benjamin ULg; Delaplace, Pierre ULg et al

Poster (2014, June)

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative ... [more ▼]

Wireworms, clock-beetles' larvae (Coleoptera, Elateridae), are below ground pests of many crops. They cause dramatic yield losses worldwide. Research on their ecology is crucial to undertake innovative management strategies. In the field of chemical ecology, multitrophic interactions occurring in the rhizosphere are gaining increasing attention from entomologists and agronomists. Our research aims at unveiling the role of volatile organic compounds (VOC) involved in wireworms' foraging behavior, putatively leading to host localization and/or host recognition. [less ▲]

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See detailStereoselective synthesis of peptidoglycan fragments on solid support
Simon, Justine ULg; Lamborelle, Nicolas ULg; Joris, Bernard ULg et al

Poster (2014, June)

The mammalian proteins, Nod1 and Nod2, are able to recognize peptidoglycan motifs during bacterial infection. Interestingly, Nod1 is a detector of peptides and muropeptides containing the meso-2,6 ... [more ▼]

The mammalian proteins, Nod1 and Nod2, are able to recognize peptidoglycan motifs during bacterial infection. Interestingly, Nod1 is a detector of peptides and muropeptides containing the meso-2,6-diaminopimelic acid (m-A2pm), a non-proteinogenic amino acid found in Gram- bacteria. In this work, we describe a synthesis of peptidoglycan motifs entirely on solid support. Solid-Phase Peptide Synthesis (SPPS), Cross Metathesis (CM) and sugar chemistry are three methods to anchor respectively amino acids, m-A2pm and sugars derivatives on a resin as solid support. [less ▲]

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See detailExecutive function and grey matter atrophy in healthy aging: A voxel-based morphometry analysis
Manard, Marine ULg; Bahri, Mohamed Ali ULg; Salmon, Eric ULg et al

Poster (2014, June)

Introduction Executive functioning is one of the cognitive domain that declines in healthy aging (Salthouse, Atkinson, & Berish, 2003). In addition, neuroimaging studies pointed out diverse ... [more ▼]

Introduction Executive functioning is one of the cognitive domain that declines in healthy aging (Salthouse, Atkinson, & Berish, 2003). In addition, neuroimaging studies pointed out diverse neurobiological modifications associated to normal aging, such as reduced grey and white matter volumes and cortical thickness (Raz & Rodrigue; 2006). In that context, Voxel Based Morphometry (VBM; Ashburner & Friston, 2000) and Partial Least Square (PLS; McIntoch at al., 1996, 2004) were used to investigate the effect of grey matter atrophy on executive abilities in normal aging. Methods Thirty six young (age range: 18-30) and 43 healthy older (age range: 60-78) adults were included in this study. Executive functioning was assessed by inhibition, updating and shifting tasks (Miyake et al., 2000), and a composite score for general executive ability was created. Structural high resolution T1-weighted images were acquired with a 3T head-only scanner using a standard transmit-receive quadrature head coil (Siemens, Allegra, Erlangen, Germany). The structural images were segmented using VBM8 toolbox, normalized to the MNI stereotaxic space and the resulting grey matter volume images were smoothed (Gaussian kernel: FWHM 8mm). PLS analyses were performed to determine regional grey matter volume differences between young and older adults, and next to identify the regional grey matter volumes specifically associated to executive performance in older participants (p<0.001). PLS is a validated multivariate approach that robustly identifies whole brain activity patterns correlated with behavioral data or experimental design (i.e., scores, conditions or tasks). Results Behavioral data showed a significant age-related decline in executive functioning (t=-5.43; p<.001). MRI analyses showed that significant age-related grey matter volume decrease was mostly observed across a large network including frontal, parietal, and temporal regions. Moreover significant positive correlations between the executive score and the grey matter volumes in older participants were found in a subset of these cortical areas: the inferior, middle and superior frontal cortex, the pre and postcentral gyri, the anterior and middle cingulate cortex, the inferior and superior parietal regions, the retrosplenial cortex, and finally, the inferior, middle and superior temporal regions. Discussion This study first replicated that executive abilities decline with age (Salthouse et al., 2003). This age-related executive decline is related to specific cerebral regions within a large fronto-temporo-parietal network sensitive to age. Interestingly, the areas whose atrophy is linked to executive abilities are quite similar to those evidenced in functional neuroimaging studies in young participants (see Collette & Van der Linden, 2002; Collette, Hogge, Salmon, & Van der Linden, 2006 for reviews). Therefore, using PLS multivariate analyses, we demonstrated that executive changes in normal aging are not dependent on atrophy in frontal areas only but rather comes from a grey matter volume decrease in a large antero-posterior brain network. [less ▲]

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See detailEffect of plant defence elicitor on aphid and disease cross infestations
Bosquée, Emilie ULg; Oumarou, Saadatou; Qiu, Dewen et al

Poster (2014, June)

Various bio-aggressors can infest potato plants (Solanum tuberosum L.) throughout its life cycle. In addition to aphids, in particular Myzus persicae Sulzer which transmits Potato virus Y (PVY), plant ... [more ▼]

Various bio-aggressors can infest potato plants (Solanum tuberosum L.) throughout its life cycle. In addition to aphids, in particular Myzus persicae Sulzer which transmits Potato virus Y (PVY), plant pathogenic fungus such as Botrytis cinerea are able to cause damage. To determine the interactions between various bio-aggressors on potato plant defence mechanisms, (1) the effect of an attack by M. persicae followed by an attack by B. cinerea and vice versa, as well as (2) the effect of an elicitor on biological parameters of M. persicae and development of B. cinerea were assessed. On the other hand, (3) the effect of Botrytis cinerea and an elicitor on the efficiency of transmission of PVY by M. persicae was examined. The previous infection by B. cinerea resulted in a significant decrease in growth rate and a sharp reduction of M. persicae fertility, while the infection level of B. cinerea followed by M. persicae infestation was non-significant. Despite a reduction in growth and fertility of M. persicae during the first days of observation, the effect of elicitor on the biological parameters of M. persicae as well as on the development of B. cinerea was non-significant. Regarding the investigations on the PVY transmission by M. persicae, when the elicitor or Botrytis is previously applied on the plant, a significant reduction in the rate of transmission was observed. [less ▲]

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See detailCan we interpret linear kernel machine learning models using anatomically labelled regions?
Schrouff, Jessica ULg; Monteiro, Joao; Joao Rosa, Maria et al

Poster (2014, June)

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See detailBacteria, bonds between classical karsts and karsts in silicated non carbonated rocks ?
Willems, Luc ULg

Poster (2014, June)

For several years, similar karsts to those found in the limestone have been observed in various silicated non-carbonated rocks. Several morphological arguments show that a complete dissolution of rocks is ... [more ▼]

For several years, similar karsts to those found in the limestone have been observed in various silicated non-carbonated rocks. Several morphological arguments show that a complete dissolution of rocks is necessary to explain the formation of some caves and other related forms independently of hydrotermalisme phenomena. However, the physico-chemical processes generally considered do not provide a satisfactory explanation to this dissolution. Bacterial activity found deep in many lithologies provides a solution to this apparent contradiction. [less ▲]

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See detailInhibitors of glycosylhydrolases as potential insecticides : focus on aphid model
Bosquée, Emilie ULg; Vandermoten, Sophie; Richel, Aurore ULg et al

Poster (2014, June)

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are ... [more ▼]

Beside conventional neurotoxic compounds, new kinds of insecticides are investigated and new specific targets are in current research. According to the energy metabolic pathway, several enzymes are interesting to bring potential specific control of arthropods. Indeed, glycosylhydrolase group is very diversified from glucanases to trehalases, until chitinases. Different kinds of inhibitors were here tested to determine their potential role as new targetted aphicides. After different assays using the selected inhibitors in artificial diets, the most efficient molecules at 50-100 μg ml-1were kept for further proteomic tasks. The proteome patterns of aphids related to different inhibitor treatments were determined by two dimension electrophoresis, 2D-Differencial In Gel Expression (2D-Dige) coupled with mass spectrometry (ESI-MS-MS and Maldi-Tof-MS-MS) and data bank investigations. Particular proteins of interest were selected and accurately characterised with both fundamental but also applied views. Not only the carbohydrate metabolic pathway was disturbed with the use of glycosylhydolases inhibitors, other primary functions were also modified (amino acid synthesis, stress response, etc). This proteomic approach was discussed as an interesting and reliable tool to study the biologically involved proteins from aphids in response to specific tested enzymatic inhibitors with further ideas to be promoted as new insecticides to control insect pests. [less ▲]

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See detailEffect of task demands on phonological acquisition : the acquisition of phonemes in French speaking children aged 30 to 53 months in four different contexts.
Maillart, Christelle ULg; Vaucel, Cécile; Macleod, Andrea

Poster (2014, June)

When children first begin to produce the phonemes of their language, their productions are characterized by a high degree of variability (e.g., Ferguson & Farwell, 1975) and are influenced by task demands ... [more ▼]

When children first begin to produce the phonemes of their language, their productions are characterized by a high degree of variability (e.g., Ferguson & Farwell, 1975) and are influenced by task demands (Khami, Catts, & Davis, 1984). As children’s phonological representations become more defined, their productions become more stable and less influenced by the task demands. Despite the clinical significance of phonological variability, there exists no normative data that can be used to objectively describe this variability in French. The goal of the present study was to describe variability and consistency among French-speaking children between the ages of 30 and 53 months, according to task demands. A total of 153 children participated in the present study and were equally distributed in four groups (aged 30-35, 36-41, 42-47, and 48-53 months). We created a picture identification task with 65 target words, which contained the consonants of French in word initial, medial and final position. The children were asked to produce these words in four different contexts : 1) picture naming ; 2) word repetition ; 3) sentence repetition ; 4) spontaneous language. Two measures of consistency were used. (1) A consonant level analysis that investigated the stability of phonological accuracy. (2) A word level analysis that investigated the consistency of productions across the four tasks. We predict that younger children will be more influenced by changes in task complexity than older children. [less ▲]

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See detailThe Impact of Dual-Tasking on Verbal Short-Term Memory in Children with Specific Language Impairment
Leclercq, Anne-Lise ULg; Maillart, Christelle ULg; Lange, Manon et al

Poster (2014, June)

Limitations in general processing capacities have been proposed to account for poor verbal short-term memory (STM) performances in children with SLI. Previous studies observed that STM performances ... [more ▼]

Limitations in general processing capacities have been proposed to account for poor verbal short-term memory (STM) performances in children with SLI. Previous studies observed that STM performances decreased to a larger extent in children with SLI as compared to their unaffected peers when the processing demands of the task increased (e.g., Ellis Weismer, et al., 2005; Montgomery, 2000a,b). However, in these studies, the increase in attention processing demands went with an increase in linguistic processing demands. Since children with SLI experience language processing problems, it is not clear whether general attention problems or language processing problems are at the root of their larger performance decrease as compared to their unaffected peers. This study aims at directly assessing the hypothesis that limitations in general attentional capacity are at the root of poor STM performances in children with SLI, using an attention demanding visual search task administered concurrently with nonword repetition task. Twenty-three children with SLI, 23 age-matched children, and 23 nonword span-matched children performed immediate serial recall tasks of nonwords. The STM lists were presented either alone or concurrently with the target detection task. Moreover, the target detection task either stopped or continued when children had to recall the nonwords. Results show a main effect of dual task condition on both nonword repetition accuracy and target detection accuracy. Performances in children with SLI were not more affected than in controls by the necessity to perform a concurrent visual attention task during nonword lists presentation. However, nonword recall seemed to be more challenging for children with SLI than for age-matched controls. Indeed, performances in the visual task were lower in children with SLI than in their age-matched controls, but not as compared to nonword span-matched controls. [less ▲]

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See detailRole of estradiol in the feminization of lordosis behavior in female mice
Trouillet, Anne-Charlotte ULg

Poster (2014, June)

The classic theory of mammalian brain and behavioral sexual differentiation holds that an organizational action of testosterone, secreted perinatally by the male’s testes, controls male-typical aspects of ... [more ▼]

The classic theory of mammalian brain and behavioral sexual differentiation holds that an organizational action of testosterone, secreted perinatally by the male’s testes, controls male-typical aspects of brain and behavioral development, whereas no active perinatal sex hormone signaling is required for female-typical differentiation. However, it has recently been shown using aromatase knock out (ArKO) mice, which are deprived of estradiol due to a targeted mutation in the aromatase gene, that estradiol may also actively contribute to the differentiation of female-typical aspects of behavior over a specific pre-pubertal period. Female ArKO mice showed significantly lower levels of lordosis behavior than wild type controls following adult ovariectomy and treatment with ovarian hormones. This deficit was restored by treating female ArKO mice with estradiol benzoate between postnatal days 15 and 25. However, the mechanism by which estradiol acts prepubertally in female mice to feminize lordosis behavior remains to be elucidated. Therefore, in a first attempt, we are determining which neuropeptides are in particularly sensitive to estradiol action over the prepubertal period. We will focus on neuropeptides which have been shown to be implicated in lordosis behavior. Studies by the group of Micevych have proposed an important role for NPY and beta-endorphin (B-END) neurons in the arcuate nucleus (ARC) in the estradiol-mediated activation of lordosis behavior in female rats. An in vitro study recently showed that kisspeptin directly activates ARC B-END neurons. This is particularly interesting since unpublished results from our laboratory showed that Kp neurons are directly involved in the expression of lordosis behavior. We are thus currently determining the expression of NPY, B-END, and kisspeptin in the ARC as well as μ-opioid receptors MORs in the MPN over the prepubertal period and their possible modulation by prepubertal estradiol treatment. [less ▲]

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See detailResearch of phosphate accumulating microorganisms from WWTPs for the recovery of phosphorus from organic wastes (3BV.3.47)
Tarayre, Cédric ULg; Michels, Evi; Buysse, Jeroen et al

Poster (2014, June)

Many wastes containing reusable components, such as nitrogen, phosphorus and potassium, are not exploited through ideal processes. As an example, in Wallonia (Belgium), the main treatment applied to ... [more ▼]

Many wastes containing reusable components, such as nitrogen, phosphorus and potassium, are not exploited through ideal processes. As an example, in Wallonia (Belgium), the main treatment applied to sewage sludge consists in incinerating the material. Such a process is chosen when the heavy metals are too concentrated in the sludge, preventing an agricultural use. However, sewage sludge, as well as manure, slurry and digestate, contain notable amounts of nutrients (nitrogen, phosphorus and potassium). Some Waste Water Treatment Plants (WWTPs) are actually designed in order to promote Phosphate Accumulating Organisms (PAOs), able to store or release phosphorus in accordance with the environmental conditions. The aim of this work is to isolate PAOs from WWTPs and evaluate their applicability to phosphorus recovery from organic wastes. Metagenomics and metabolic properties are also considered. This work is supported by the BioRefine Project, a European project in which various member states focus on recovery of inorganics from organic wastestreams. [less ▲]

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See detailSorting of crop residues and fossil bones from soil by NIR Hyperspectral Imaging
Vincke, Damien; Eylenbosch, Damien ULg; Baeten, Vincent et al

Poster (2014, June)

Soil is a complex matrix containing a wide variety of constituents of interest for disciplines like agronomy or archaeology; it could either be crop residues like roots and straws or bones and ceramics ... [more ▼]

Soil is a complex matrix containing a wide variety of constituents of interest for disciplines like agronomy or archaeology; it could either be crop residues like roots and straws or bones and ceramics. Current challenges comprise the detection of these constituents as well as the assessment of their qualitative parameters by means of fast and non-destructive analytical methods. The scope of this work is to present two applications using Near Infrared Hyperspectral Imaging (NIR-HSI) combined with chemometrics to sort constituents of soil and to assess their qualitative parameters. The first application concerns the feasibility study of using NIR-HSI to sort crop residues such as roots and straws in soil. The second application aim to develop a method to assess the level of collagen preservation in fossil bones. [less ▲]

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See detailThe X-ray emission of the massive stars population in Cyg OB2
Rauw, Grégor ULg; Nazé, Yaël ULg; Wright, Nick et al

Poster (2014, June)

Cygnus OB2 contains a wealth of massive stars of spectral types O, B and Wolf-Rayet. In the framework of a Chandra legacy program to study the X-ray emission from this important association, we have ... [more ▼]

Cygnus OB2 contains a wealth of massive stars of spectral types O, B and Wolf-Rayet. In the framework of a Chandra legacy program to study the X-ray emission from this important association, we have studied the X-ray properties of its massive stars population. We show that the O-stars in Cyg OB2 follow a well-defined scaling relation between their X-ray and bolometric luminosities: log(Lx/Lbol) = −7.2 ± 0.2. Except for the brightest O-star binaries, there is no general X-ray overluminosity due to colliding winds in O-star binaries. Roughly half of the known B-stars in the surveyed field are detected, but they fail to display a clear relationship between Lx and Lbol. Out of the three WR stars in Cyg OB2, probably only WR144 is itself responsible for the observed level of X-ray emission, at a very low log(Lx/Lbol) = −8.8±0.2. The X-ray emission of the other two WR-stars (WR145 and 146) is most probably due to their O-type companion along with a moderate contribution from a wind-wind interaction zone. [less ▲]

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See detailInvestigation of differential virus transmission efficiency in aphid strains: from biological to proteomic assays
Bosquée, Emilie ULg; Francis, Frédéric ULg

Poster (2014, June)

Aphids are well known for their variable efficiency in virus transmission to host plant. Not only aphid species but also aphid strain is an important factor to consider in the plant-aphid-virus ... [more ▼]

Aphids are well known for their variable efficiency in virus transmission to host plant. Not only aphid species but also aphid strain is an important factor to consider in the plant-aphid-virus interactions. In order to investigate these relations, different approaches should be developped from biological observations assessing the virus transmission efficiency to molecular tasks to better know the involved mechanisms in the aphid vector. After a period of virus acquisition on an artificial diet (depending on the kind of transmission, permanent or non permanent ways), the virus transmission rate were assayed and followed by the determination of the presence of virus in the aphid by PCR or immudetection. The aphids were then collected to investigate the variation of aphid proteome and potential involvement in virus interactions. Changes in protein expressions were investigated using a 2D-DIGE approach comparing most and least efficient aphid strains selecting different aphid – virus models (PVY and PLRV in potato, BYDV in wheat, CMV on tobacco) . The proteome changes were analysed using the samespot software. Protein spots with significant up- and down expressions were then mechanically picked, trypsin digested and analysed by Maldi-Tof-Tof. Significantly changed proteins were classify according to metablic pathways and biological functions. Interesting proteins found to probably interact with virus were not only detected from aphid but also from related bacterial symbionts. Theses results were discussed in order to better understand virus – vector relations and potentially promote new ways to control virus transmitted by hemipteran pest. [less ▲]

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See detailSTUDIO in vitro DEI PARAMETRI DI COINFEZIONE E SUPERINFEZIONE CHE INFLUENZANO LA RICOMBINAZIONE NEI NOROVIRUS
Di Felice, Elisabetta; Ceci, Chiara; Zonta, William ULg et al

Poster (2014, June)

I norovirus (NoV) sono piccoli virus (38-40 nm) a RNA monocatenario sprovvisti di envelope appartenenti alla famiglia Caliciviridae. I NoV attualmente vengono riconosciuti come una delle più importanti ... [more ▼]

I norovirus (NoV) sono piccoli virus (38-40 nm) a RNA monocatenario sprovvisti di envelope appartenenti alla famiglia Caliciviridae. I NoV attualmente vengono riconosciuti come una delle più importanti cause di gastroenterite acute di origine non batterica nell'uomo coinvolgendo tutte le classi di età e soprattutto contesti comunitari. I meccanismi molecolari che influenzano l'evoluzione dei NoV sono l'accumulo di mutazioni puntiformi e la ricombinazione. L’obiettivo sarà quello di dimostrare che la ricombinazione è un evento che può essere influenzabile dall’impiego di diversi parametri di coinfezione/superinfezione. In letteratura, gli studi sugli eventi ricombinanti che caratterizzano i NoV umani risultano piuttosto limitati a causa dell'assenza di un substrato cellulare che ne permetta la replicazione in vitro. Nel presente lavoro è stato sviluppato un modello sperimentale basato sull’impiego dell’unico NoV, il norovirus murino (MNV), in grado di replicare su substrato cellulare. A tal fine monostrati di cellule RAW264.7 sono stati coinfettati e superinfettati con due ceppi di MNV (CW1 e WU20) utilizzando diversi indici di molteplicità (MOI) e differenti tempi di infezione. I surnatanti sono stati collezionati a 24 e 48 ore post-infezione e quindi sottoposti a metodo delle placche. All’interno della popolazione virale risultante da tale coinfezione/superinfezione, 36 cloni per ciascuna condizione sono stati selezionati e purificati dalle placche e, successivamente, utilizzati per infettare nuovi monostrati cellulari di RAW264.7. Il monitoraggio degli eventi ricombinanti è stato eseguito mediante PCR e Real-Time PCR dopo estrazione dell'RNA virale e retrotrascrizione, impiegando due set di primer in grado di amplificare le regioni site all’estremità iniziale di ORF1 e all’estremità terminale di ORF3. I risultati che permetteranno di quantificare la distribuzione dei ceppi presenti nel surnatante della superinfezione, sono ancora in corso di analisi. [less ▲]

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See detailMembrane interactions of cyclic lipodepsipeptides from the viscosin group
Geudens, Niels; Feher, Krisztina; De Vleeschouwer et al

Poster (2014, June)

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See detailToward a Characterization of Western Operatic Singing Voices
Larrouy, Pauline ULg; Magis, David ULg; Nowak, Marion et al

Poster (2014, May 29)

Objective: One can easily recognize the musical style of a singer by listening to his/her sung performance. Several acoustical parameters of the Western operatic singing technique have been studied ... [more ▼]

Objective: One can easily recognize the musical style of a singer by listening to his/her sung performance. Several acoustical parameters of the Western operatic singing technique have been studied. However, the number of parameters could be extended and the effect of melody on these parameters remains unclear. By observing the effects of melody and technique on acoustical and musical parameters of the singing voice, this study aims at further characterizing the Western operatic singing technique. Methods: Fifty professional singers performed two contrasting melodies (popular song and romantic melody) with two vocal techniques (with and without operatic singing technique). The common quality parameters (energy distribution, vibrato rate and extent), perturbation parameters (standard deviation of the fundamental frequency, signal-to-noise ratio, jitter and shimmer) and musical features (fundamental frequency of the starting note, average tempo, and sound pressure level) of the 200 sung performances were analyzed. Results: The results show that the choice of melody had a limited impact on the acoustical and musical parameters observed, whereas a particular vocal profile appeared depending on the vocal technique employed. By examining these parameters in a theoretical model, this study highlights the relevance of vibrato rate, sound level, energy distribution, fundamental frequency of the starting note and tempo in describing the Western operatic singing technique. Conclusions: This study confirms that vocal technique affects most of the parameters examined and that the effect of melody is limited. In addition, the observation of quality and musical parameters contributes to a better understanding of the operatic singing technique. Conversely, the perturbation parameters don’t seem to take part in the characterization of operatic singing voices. Although the suggested theoretical model needs to be further developed in future research, it already generates implications for research and teaching. [less ▲]

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See detailJuvenile sexual offenders: Can their language tell us how their mind works?
Courtain, Audrey; Glowacz, Fabienne ULg

Poster (2014, May 27)

A significant proportion of sexual delinquency being committed by juveniles, various fields of research have studied this topic. Still, little is known about the relation between the linguistic ability ... [more ▼]

A significant proportion of sexual delinquency being committed by juveniles, various fields of research have studied this topic. Still, little is known about the relation between the linguistic ability and the cognitive functioning of this specific youth. Rooted in scientific works which have explored indirectly the point, this poster attempt to question the quality of language as a mean to find out how their mentalization occurs, but also to question how their cognitive processes (e.g. empathy) influence their language. These hypothesis are to be tested soon with a clinical sample of 47 participants and with different measures (e.a. MACI, verbal IQ, IRI). Hence, the opportunity to evaluate, among others, empathy deficits and cognitive distortions through language can be considered a promising approach allowing new perspectives for prevention, assessment and treatment of juvenile sexual offenders. [less ▲]

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See detailMaintaining people with multiple sclerosis at work: Validation of a questionnaire identifying their professional difficulties
Blavier, Adelaïde ULg; Monisse, Aurélie; Berkail, Radia et al

Poster (2014, May 27)

The purpose of this paper is to present the construction and validation of a questionnaire in order to evaluate the specific work difficulties and compensation mechanisms developed by multiple sclerosis ... [more ▼]

The purpose of this paper is to present the construction and validation of a questionnaire in order to evaluate the specific work difficulties and compensation mechanisms developed by multiple sclerosis patients (MS). At the moment, only few very recent questionnaires (in English) are constructed in order to highlight the link between the patients’ cognitive deficits with their professional situation (Doogan & Playford, 2014; Honan et al., 2012; McFadden et al., 2012). This lack of accurate assessment is detrimental to the patients’ job retention. Our questionnaire was constructed from review of literature and interviews of patients and experts. In order to validate our questionnaire and to test its specificity to MS patients, three groups of participants answered the questionnaire: MS patients, diabetic patients (diabetes is also a chronic illness but without any cognitive deficits contrary to MS) and a control group. We controlled the effect of anxiety and depression and we conducted a factorial analysis that showed the existence of 3 factors: the ergonomic factor (that includes cognitive difficulties and resources and adaptation process), the description of work situation and the social support. The three groups of participants obtained similar results for the work description and the social support while the group of patients with MS obtained a higher score than the other 2 groups for the ergonomic factor. These results suggest that our questionnaire is specific to the MS population and to the difficulties they specifically meet in their work situations. These results highlight new research opportunities and specific ways to increase job retention in MS population. [less ▲]

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See detailInfluence of melodic context on the perception of vocal pitch accuracy
Beeken, Manon; Morsomme, Dominique ULg; Larrouy, Pauline ULg

Poster (2014, May 27)

In order to categorize sung performances as “in tune” or “out of tune”, one can measure the deviation between the performance and the musical notation. Depending on the study, a deviation of a semitone ... [more ▼]

In order to categorize sung performances as “in tune” or “out of tune”, one can measure the deviation between the performance and the musical notation. Depending on the study, a deviation of a semitone (100 cents) or a quartertone (50 cents) is considered as “out of tune”. However, these values are arbitrary and the current study aims to define perceptual thresholds of pitch accuracy in a melodic context. For this purpose, melodic sequences were manipulated, from “in tune” (deviation of 0 cent) to “out of tune” (10 to 80 cents, in 10 cents steps). In a 2x2x2 design we systematically varied the conditions of: melodies (ascending/descending target-interval), type of errors (interval or tonality deviation), and direction of the deviation (enlargement or compression). The sequences were presented to 30 non-musicians using the method of limits procedure, in a test/retest paradigm. For each condition, they were asked to specify whether the presented singing performances were “in tune” or “out of tune”. The results showed that participants were consistent in their evaluation between the test and the retest. The pitch accuracy threshold (M = 29 cents, ES = .75) was not influenced by the melody, the type of errors, and the direction of the deviation. This study highlights the ability of non-musicians to perceive small pitch deviations (less than a quartertone) in a melodic context. This finding elucidates on the concept of pitch accuracy and therefore yields the opportunity to revise objective tools for the evaluation of singer pitch accuracy. [less ▲]

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See detailLong protocols to Rorschach Comprehensive System and a posteriori reduction of number of responses: What is the impact on the clinical interpretation ?
Dufour, Cristelle; Englebert, Jérôme ULg; Blavier, Adelaïde ULg

Poster (2014, May 27)

Our study was interested in the exceptionally long protocols, superior to 55 answers, supplied by five subjects in the test of Rorschach according to the method of the Comprehensive System. In order to ... [more ▼]

Our study was interested in the exceptionally long protocols, superior to 55 answers, supplied by five subjects in the test of Rorschach according to the method of the Comprehensive System. In order to gain understanding of which attitude to adopt in front of this kind of protocol, we made a a posteriori reduction of the number of answers by basing us on the recommendations of Exner (Exner, on 2001), then a comparative study between the clinical interpretation realized with all of the answers and with only the first five answers by board. We also replicate this methodology of a posteriori decrease of the number of answers with four answers by board according to the new recommendations of the system R-PAS of Meyer and al. (Meyer and al, on 2009). The sample consists of three raw coal subjects and two psychiatric subjects. Our analysis highlighted a stability of certain variables (EB, Lambda, EA for example) but a difference in the psychological profile of the subjects after reduction. We observed a clarification of the fundamental difficulties to the psychiatric subjects and rather a neutralization of these difficulties for the raw coal subjects, with particularly defence mechanisms which seem more adapted. In our sample, the consideration of all of the answers or only of the partial protocol thus brings a difference in the clinical interpretation ; as a consequence any reduction should be made with big caution. Our study allows to discuss current practices of the test of Rorschach, by looking for a compromise between the inherent constraints to the validity of the test and the questions of the clinical complexity decrease appropriate to any initiative of standardization. [less ▲]

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See detailDetection of eye movements specific to drowsiness and their relation with subjective assessment: A cognitive ergonomic approach.
Blavier, Adelaïde ULg; Montagnino, Cédric; Wertz, Jérôme ULg et al

Poster (2014, May 27)

Drowsiness is one of the major factors explaining accidents, particularly in traffic accidents but also in work situations with serious consequences (e.g. medicine). The drowsiness may be assessed by ... [more ▼]

Drowsiness is one of the major factors explaining accidents, particularly in traffic accidents but also in work situations with serious consequences (e.g. medicine). The drowsiness may be assessed by diverse measures that vary from physiological and unconscious data (e.g. EEG) to subjective and conscious evaluation. In their daily life, people are used to evaluate their drowsiness by subjective assessment and research observes a great inter-individual variation in this evaluation. Moreover, the subjective evaluation is dependent on the situation and the risk perceived by the person (e.g., new versus usual situations, simple versus complex environments, etc.). In this theoretical context, our purpose was to investigate the links between 1) objective performance (reaction time) measured by a psychomotor vigilance task (PVT), 2) data from eye movements and 3) subjective assessment of drowsiness (measured with Karolinska Sleepiness Scale, KSS). 12 persons, aged from 20 to 56, participated individually. They were asked to respect a 60% sleep deprivation during the night before the experiment and to not drink any energy drinks the day of the experiment. The experiment was conducted between 1 and 3 PM after a heavy lunch in order to increase the circadian effect. Moreover, the temperature of the room was 25° in order to increase drowsiness. Each participant was asked to perform 4 PVT. However, although 100% of participants performed the first two PVT, only 66% were able to perform the third PVT and only 33% of participants performed the fourth and last PVT. Our results showed an effect of time on objective performance, eye movements and subjective assessment of drowsiness in PVT 1 and 2: significant increase of reaction time, increase of eye closure and perclos, reduction of pupil diameter and increase of subjective drowsiness estimation (KSS). Only the frequency and duration of blinks remained constant across time. In PVT 3 and 4, data from eye movements and objective performance (reaction time) did not vary anymore across the time. Only the subjective estimation of drowsiness (KSS) continued to increase. Furthermore, subjective estimation of drowsiness was differently correlated with eye movements and objective performance across the PVT; it was significantly correlated with reaction time (PVT 1,2,3), blink frequency and duration (PVT 1,2,3), perclos (PVT 1,2,3,4), eye closure (PVT 2,3), pupil diameter (PVT 1,2,3,4). These results are discussed and integrated in an ergonomic approach in order to analyze the links between objective performance, eye movements and subjective assessment of drowsiness. [less ▲]

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See detailSynthesis of a glucosamine labeled amphiphilic polymer for drug delivery application
Riva, Raphaël ULg; Boyère, Cédric; Debuigne, Antoine ULg et al

Poster (2014, May 27)

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See detail[18F]UCB-H AS A BRAIN SV2A RADIOTRACER: A FIRST CLINICAL TRIAL
Bahri, Mohamed Ali ULg; Bastin, Christine ULg; Aerts, Joël ULg et al

Poster (2014, May 27)

[18F]UCB-H is a fluorine-18 radiolabelled PET imaging tracer with a high affinity for the synaptic vesicle protein 2A (SV2A). This protein, involved in vesicle trafficking and widely distributed in the ... [more ▼]

[18F]UCB-H is a fluorine-18 radiolabelled PET imaging tracer with a high affinity for the synaptic vesicle protein 2A (SV2A). This protein, involved in vesicle trafficking and widely distributed in the brain, represents the binding site and the primary mechanism of the antiepileptic drug levetiracetam. Levetiracetam has recently been suggested to reduce synaptic deficits in a mouse Alzheimer’s disease model and to improve cognition in patients with amnestic mild cognitive impairment, suggesting a possible role for this protein in synaptic integrity. The objective of this study was to investigate the cerebral distribution of [18F]UCB-H in healthy human volunteers. Dynamic PET imaging of the head of four healthy volunteers was performed over 100 minutes after injection of 170.4 ± 24.9 MBq of GMP produced [18F]UCB-H. The input function was acquired by arterial blood sampling during the dynamic PET acquisition. Blood data analysis showed a consistent tracer amount in whole blood and plasma indicating a very low degree of binding of the tracer to the red blood cells. Unchanged [18F]UCB-H fraction in plasma follows a bi-exponential behavioral decrease with a starting fraction of 92% of the injected amount of the tracer, measured at 3 min post injection. This fraction decreases to about 50% at 10 min post injection. The [18F]UCB-H PET data revealed a high and rapid uptake in the grey matter structures, matching the known ubiquitous distribution of SV2A in the brain. The kinetics of the tracer in the brain was characterized by an initial high uptake phase followed by rapid washout allowing the standard compartmental modeling (1-tissue compartment, 2-tissue compartment, and Logan graphical analysis). The three models gave consistent results. The two-tissue compartment model fitted the experimental data best and provided a total distribution volume of [18F]UCB-H in the brain greater than 7 mL/cm3 and a specific distribution volume around 3 mL/cm3. Our results indicate that [18F]UCB-H is a new radiotracer for brain SV2A proteins suitable for human studies. Further studies are warranted to assess SV2A modifications in neurological pathologies such as Alzheimer’s disease. [less ▲]

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See detailEmpathy and social relationships in suicidal adolescents
Jadin, Aurore ULg; Vermaelen, Noémie; Blavier, Adelaïde ULg

Poster (2014, May 27)

Empathy and suicide among minor people are two research topics currently very explored. Psychologists often speak about suicide because it represents the second cause of mortality among 15-24-year-old ... [more ▼]

Empathy and suicide among minor people are two research topics currently very explored. Psychologists often speak about suicide because it represents the second cause of mortality among 15-24-year-old adolescents (Delvenne, 2005). Several studies have already analyzed the links between empathy skills and some psychopathology (behavioral disorders, hyperactivity and alcoholism) but no research before this one has developed empathic abilities in suicidal adolescents. The aims of the present study were respectively to examine suicidal adolescents’ empathy skills, interpersonal capacities and to investigate the quality of their social relationships. [less ▲]

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See detailCorrelation and integration of the Rorschach Comprehensive System and the TCI-R questionnaire
Rentmeister, Daniel; Blavier, Adelaïde ULg; Di Piazza, Laetitia ULg et al

Poster (2014, May 27)

In this study, a dual purpose is sought. First, we statistically compare the Rorschach test interpreted by the Comprehensive System from J.E. Exner and the Temperament and Character Inventory – Revised by ... [more ▼]

In this study, a dual purpose is sought. First, we statistically compare the Rorschach test interpreted by the Comprehensive System from J.E. Exner and the Temperament and Character Inventory – Revised by R. Cloninger to highlight their differences and similarities. Second, through clinical cases, we discuss the relevance of integrating the results obtained by these two tools to establish a comprehensive and consistent psychological profile of an individual. For the statistical comparison, a sample of 27 “healthy” subjects (M = 24.37 years, SD = 2.75) was first submitted to the Rorschach test. Then, immediately after, each subject completed the TCI-R. A correlation analysis (Pearson Rho) was done between various Index and a Bonferroni adjustment was made. For the case studies, 3 subjects were recruited. Anamneses were carried out and the Rorschach test and TCI-R administered. Our first results, which are to be taken with caution because of the small number of subjects in the sample, must be qualified and discussed. From 2448 statistical comparisons, we select the most relevant and discuss different correlation results. The case studies show a concordance in social relationships and impulsivity; and show that the information peculiar to each test allows us to complete the subject’s profile. Finally, it is by addressing two different epistemologies underlying these two tests that we can best explain the psychological differences highlighted in the same individuals. We conclude by suggesting that this difference in results must certainly be understood in an integrative logic and emphasizes the complementarity between these two tests. [less ▲]

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See detailAn innovative lens surface functionalization to control Posterior Capsular Opacification
Huang, Yi-Shiang ULg

Poster (2014, May 26)

Cataract is the opacity of the lens, causing impairment of vision or even blindness and the surgery is still the only available treatment today. The intraocular lens (IOL) is a polymer implant designed to ... [more ▼]

Cataract is the opacity of the lens, causing impairment of vision or even blindness and the surgery is still the only available treatment today. The intraocular lens (IOL) is a polymer implant designed to replace the natural lens in the cataract surgery. However, the bio-inert materials could not satisfy the unmet need in the secondary cataract control. Posterior capsular opacification (PCO, or Secondary Cataract), characterized by a thick and cloudy layer of lens epithelial cells (LECs), is the most common postoperative complication. For the present study, a bioactive molecule is immobilized onto the conventional acrylic hydrophilic polymer pHEMA (Poly(2-hydroxyethyl methacrylate)) using oxygen plasma treatment followed by dip-coating deposition. The RGD peptide sequence, being well-known for its ability to promote cellular attachment by binding to integrin receptors, is designed to stimulate the adhesion of LECs on the IOL. The data have shown the peptide immobilized biomaterial not only exhibits similar optical and physical properties, but also reveals enhanced bio-logical properties in cell adhesion and cell morphology maintenance. By means of surface functionalization of IOL to stimulate LECs adhesion, the secondary cataract could be controlled. [less ▲]

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See detailMultilayered chitosan-based fibers for skin regenaration applications
Croisier, Florence ULg; Detrembleur, Christophe ULg; Jérôme, Christine ULg

Poster (2014, May 26)

Chitosan is a natural polymer derived from the chitin of crustacean or mushroom shells, that intrinsically presents haemostatic, mucoadhesive, antimicrobial and immunostimulant properties. This ... [more ▼]

Chitosan is a natural polymer derived from the chitin of crustacean or mushroom shells, that intrinsically presents haemostatic, mucoadhesive, antimicrobial and immunostimulant properties. This polysaccharide has shown a great potential for biomedical and pharmaceutical applications, on account of its remarkable compatibility with physiological medium. Besides, it is degraded in a physiological environment into non-toxic products, which make chitosan an outstanding candidate for short- to medium-term applications. In this respect, nanometric fibers are highly interesting as their assembly mimics the skin extracellular matrix structure. Such nanofibrous materials can be prepared by electrospinning (ESP). This technique uses a high voltage to create an electrically charged jet of polymer solution or melt which leads to fibers formation. Depending on the polymer characteristics (a.o. molecular weight, solution viscosity and conductivity) and processing conditions (electric potential, distance between syringe-capillary and collection plate, concentration, flow rate), polymer fibers ranging from nanometers to a few microns in diameter can be obtained and subsequently used as potential scaffolds, a.o. to form a temporary, artificial extracellular matrix. In the present study, electrospinning technique was combined with layer-by-layer deposition method (LBL) - a well-known method for surface coating, based on electrostatic interactions - in order to prepare multilayered chitosan-based nanofibers. The antibacterial properties of the obtained material were then assessed, and the presence of a multilayered deposit was confirmed by several techniques. The multilayered chitosan-based nanofibers produced present great prospects for the preparation of new biomedical scaffolds - such as wound dressings that could improve skin regeneration. [less ▲]

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