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See detailMolecular analysis of the interfacial and membrane-interacting properties of D-xylose-based bolaforms
Nasir, Mehmet Nail ULg; Legrand, Vincent; Gatard, Sylvain et al

Poster (2012, October)

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See detailAssessment of lumbopelvic movement control in tennis players with and without low back pain
GROSDENT, Stéphanie ULg; Demoulin, Christophe ULg; Lemaire, Vincent et al

Poster (2012, October)

Relevance: LBP is common among tennis players. More than one third of professional tennis players reported LBP as reason for missing at least one tournament. As impaired lumbar motor functions have been ... [more ▼]

Relevance: LBP is common among tennis players. More than one third of professional tennis players reported LBP as reason for missing at least one tournament. As impaired lumbar motor functions have been associated with LBP, it appears particularly relevant to assess lumbopelvic movement control in tennis players. Methods: Twenty amateur tennis players (male, 22.9 ± 3.0 years) were included. Subjects were pooled into two groups: 10 players with chronic LBP (mean pain duration: 3.1 ± 2.6 years, pain severity score: 3.5/10 on a pain visual analogue scale) and 10 players without LBP. The Bent Knee Fall Out (BKFO) test was used to assess the players’ ability to control movement of lumbopelvic region. BKFO was performed in supine position and monitored by means of two pressure biofeedback units inflated to 40 mmHg and positioned under the lumbar spine of the participant. The reliability of this test has been previously assessed. Players were instructed to make an active abduction-external rotation movement of the hip (45°) without concomitant lumbopelvic movement of the pelvis and low back. Pressure modification (mmHg) was recorded, each side was assessed. Results: Tennis players with LBP had a worse lumbopelvic movement control than players without LBP both for dominant (9.0 mm Hg vs 3.4 mmHg, P<0.05) as well for the non-dominant side (9.1 mmHg vs 4.6 mmHg, P<0.05). Conclusions: Tennis players with LBP experience similar alterations of motor control as those observed in sedentary people with LBP. However, it remains unclear if these alterations are the cause of the consequence of chronic LBP. Implications: Further prospective studies should assess the cause or effect relationship and should determine whether motor control exercises are effective in tennis players with chronic LBP. [less ▲]

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See detailDevelopment of a quantitative approach to measure phospholipids in dried drops by Raman spectroscopy
Malherbe, Cédric ULg; Jadoul, Laure; Gilbert, Bernard ULg et al

Poster (2012, October)

We present here the results obtained during our tentative to analyse quantitatively dried drops of phospholipidic solutions by Raman spectroscopy. Drops of different solutions of phospholipid were deposed ... [more ▼]

We present here the results obtained during our tentative to analyse quantitatively dried drops of phospholipidic solutions by Raman spectroscopy. Drops of different solutions of phospholipid were deposed onto different material supports. The spots were then analyses by confocal Raman microspectroscopy. Experimental settings have been optimised and the analysis of the intensity profile of the Raman signal inside the spot allows the establishment of a calibration curve for the determination of the phospholipids amount within a 1 µL solution. [less ▲]

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See detailPotential of CE/MS for Small Carboxylic Acids Analysis as Alternative to GC/MS Reference Analytical Methods
Far, Johann ULg; Falmagne, Jean-Bernard, ANALIS R&D; de l'Escaille, François, ANALIS R&D et al

Poster (2012, October)

GC/MS (Gas Chromatography coupled to Mass Spectrometry) is the analytical method of choice for carboxylic acids analysis because of good sensitivity, low limit of detection and the possibility to compare ... [more ▼]

GC/MS (Gas Chromatography coupled to Mass Spectrometry) is the analytical method of choice for carboxylic acids analysis because of good sensitivity, low limit of detection and the possibility to compare the pattern of fragmentation with existing databases for identification. However GC requires that the analytes are volatile. If it is not the case, the use of chemicals in order to perform the derivatization is mandatory, this may induce analytical bias. CE (Capillary electrophoresis) is a technique of choice for ions separation without prior treatments. The method is fast and do not require highly technical skills. A UV detector is the most common detection method; however electrospray mass spectrometry detection is recently gaining interest, while it really helps for structural information of the detected compounds. In this poster, the preliminary results of CE/MS analysis of several carboxylic acids are presented. All carboxylic acids are analyzed without any sample pretreatment. These acids looked at are from the “Citric Acid Cycle” including pyruvate and some isotope labeled analogues but also glyoxylate, lactate, oxalate and tartrate. Moreover, the preliminary results of a sample preparation approach to remove phosphate salts are presented. Phosphate is a very common salt that is often used in biological buffers but prevents the derivatization of carboxylic acid for GC/MS analysis and reduces the reproducibility of results for both GC/MS and CE/MS analysis. [less ▲]

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See detailDosimetry for 6-[18F]Fluoro-L-DOPA in Humans Based on Biodistribution in Mice
Bretin, Florian ULg; Warnock, Geoffrey ULg; Bahri, Mohamed Ali ULg et al

Poster (2012, October)

Aim. The objective of this work was to estimate human dosimetry for 6-[18F]Fluoro-L-DOPA (F-DOPA) from biodistribution in mice, obtained from organ harvesting at different time points and from a hybrid ... [more ▼]

Aim. The objective of this work was to estimate human dosimetry for 6-[18F]Fluoro-L-DOPA (F-DOPA) from biodistribution in mice, obtained from organ harvesting at different time points and from a hybrid method combining dynamic PET followed by organ harvesting. Materials and methods. The tissue distribution of F-DOPA over time was determined in isoflurane-anaesthetized mice. Radioassay was performed on harvested organs at 2, 5, 10, 30, 60 and 120 minutes post administration (n = 5 at each time point). Dynamic PET images were acquired in list-mode with a Siemens FOCUS 120 microPET for 120 minutes after injection and followed by radioassay of harvested organs (n = 4). List-mode data were histogrammed in 6*5s, 6*10s, 3*20s, 5*30s, 5*60s, 8*150s, 6*300s, 6*600s 3D sinograms. Final images were obtained using filtered backprojection with correction for all physical effects except for scatter. Attenuation correction resulted from a pre-injection transmission scan with a cobalt-57 point source. Organs were manually delineated. The organ time-activity-curves (TACs) from both methods were extrapolated from a simulated 35 g standard mouse to a 70 kg standard male human using a technique based on organ to bodyweight ratios. A bladder voiding scenario was used to simulate excretion every 2 h. The absorbed doses in major human organs were calculated using the extrapolated TACs with the commercially available software OLINDA/EXM (Version 1.1). Results. The extrapolated organ activity curves obtained using the harvesting and imaging methods showed a high correlation (r = 0.94 ± 0.05, p < 0.001). However, TACs from PET alone under- or overestimated the activity in individual organs in contrast to TACs obtained using the cross-calibration of the PET data with the activity in post-scan dissected organs. Those organs in the excretion pathways, comprising bladder wall, kidneys and liver, received the highest organ doses. The total body absorbed dose was 0.0118 mGy/MBq for both the imaging based and harvesting based methods. The effective dose was 0.0193 mSv/MBq for the hybrid imaging-harvesting technique and 0.0189 mSv/MBq for the pure harvesting technique. Conclusion. The doses obtained agreed well with the few results available in the literature. The hybrid technique combining dynamic PET scanning followed by organ harvesting appeared to be a good alternative to the gold standard ex vivo radioassay method. It is much faster and minimizes the effect of some weakness of the pure imaging technique, such as partial volume effect. [less ▲]

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See detailIn Ovo PET Imaging Of A Human Colorectal Carcinoma Model In Chicken Chorioallantoic Membrane
Warnock, Geoffrey ULg; Turtoi, Andrei ULg; Blomme, Arnaud ULg et al

Poster (2012, October)

Aim. The objective of this study was to use in vivo PET/CT imaging as a validation tool for a novel human colorectal carcinoma model being developed in chicken chorioallantoic membrane (CAM). For this ... [more ▼]

Aim. The objective of this study was to use in vivo PET/CT imaging as a validation tool for a novel human colorectal carcinoma model being developed in chicken chorioallantoic membrane (CAM). For this initial pilot study a cell line modeling colon cancer was selected and imaged using [18F]fluorodeoxyglucose (FDG). <br />Materials and methods. A window was made in the shell of fertilized chicken eggs and 3x106 SW1222 human colorectal carcinoma cells were implanted at day 10 post-fertilization. On day 17 the shell window was enlarged to allow direct injection of FDG (12.2 ± 4.5 MBq/egg) into a CAM blood vessel. During injection the egg was warmed on a heating pad. A mixture of ketamine/medetomidine (50 :1 mg/ml, 0.2 ml/egg) was injected into the albumin in some eggs to assess the effect of anesthesia. After FDG injection the egg was returned to the incubator for a 45 min uptake period before imaging. Imaging was performed on a Siemens Focus 120 microPET with structural CT on a General Electric eXplore CT120. A Minerve cell system allowed reproducible positioning between modalities. PET data was acquired in list mode before histogramming into a single 10 min frame for reconstruction using a 3D maximum a posteriori (MAP) method with all corrections except scatter. A standard 100 µm (theoretical) image resolution protocol (70 kV, 50 mA, 32 ms, 220 views) was used to obtain structural CT data. Image coregistration was performed in PMOD version 3.3. In a separate egg, the influence of added contrast on the CT data was investigated by adding iodinated contrast agent (Iobitridol 35 mgI/ml) to the albumin. <br />Results. FDG uptake was clear in chick and tumor, with notably high uptake at the major joints. Tumors were identified by localization of FDG uptake on the surface of the CAM. A lack of soft tissue contrast between tumor, CAM and albumin made precise structural identification of the tumor difficult. Anesthesia was crucial to image quality in both PET and CT. CT contrast between the soft tissues of the chick and surrounding albumin/structures was improved by addition of contrast agent. <br />Conclusion. For the first time we demonstrate successful imaging of FDG uptake in a human colorectal carcinoma chicken CAM model in ovo. Methods to improve structural data are under investigation and will be used in further studies. With such improvement, this model could be of great value to PET oncology imaging. [less ▲]

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See detailEUV high resolution imager on-board Solar Orbiter: optical design and detector performances.
Halain, Jean-Philippe ULg; Mazzoli, Alexandra ULg; Rochus, Pierre ULg et al

Poster (2012, October)

The EUV high resolution imager (HRI) channel of the Extreme Ultraviolet Imager (EUI) on-board Solar Orbiter will observe the solar atmospheric layers at 17.4 nm wavelength with a 200 km resolution. The ... [more ▼]

The EUV high resolution imager (HRI) channel of the Extreme Ultraviolet Imager (EUI) on-board Solar Orbiter will observe the solar atmospheric layers at 17.4 nm wavelength with a 200 km resolution. The HRI channel is based on a compact two mirrors off-axis design. The spectral selection is obtained by a multilayer coating deposited on the mirrors and by redundant Aluminum filters rejecting the visible and infrared light. The detector is a 2k x 2k array back-thinned silicon CMOS-APS with 10 µm pixel pitch, sensitive in the EUV wavelength range. Due to the instrument compactness and the constraints on the optical design, the channel performance is very sensitive to the manufacturing, alignments and settling errors. A trade-off between two optical layouts was therefore performed to select the final optical design and to improve the mirror mounts. The effect of diffraction by the filter mesh support and by the mirror diffusion has been included in the overall error budget. Manufacturing of mirror and mounts has started and will result in thermo-mechanical validation on the EUI instrument structural and thermal model (STM). Because of the limited channel entrance aperture and consequently the low input flux, the channel performance also relies on the detector EUV sensitivity, readout noise and dynamic range. Based on the characterization of a CMOS-APS back-side detector prototype, showing promising results, the EUI detector has been specified and is under development. These detectors will undergo a qualification program before being tested and integrated on the EUI instrument. [less ▲]

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See detailEffect of finger tapping frequency on abnormal subthalamic nucleus oscillations in Parkinson’s disease
Stamatakis, Julien; Noirhomme, Quentin ULg; Orban, Jonhatan et al

Poster (2012, October)

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See detailEncoded haplotype data as input to ipPCA can better resolve population clustering
Chaichoompu, Kridsadakorn ULg; Pongsakorn, Wangkumhang; Anunchai, Assawamakin et al

Poster (2012, October)

Background Studies in population genetics are mainly based on the analysis of genetic variations among different populations. With the advent of advanced genotyping technology, large number of Single ... [more ▼]

Background Studies in population genetics are mainly based on the analysis of genetic variations among different populations. With the advent of advanced genotyping technology, large number of Single Nucleotide Polymorphisms (SNPs) can be used to capture the underlying population variations. Iterative pruning principal component analysis (ipPCA) is a very powerful tool to cluster subpopulations based on their SNP profiles. However, when several similar populations are considered in the analysis, differentiating these populations can become very challenging. Haplotype has been known to capture more segregation information and higher power than SNP but due to high inference complexity, this concept has not been widely used. Recently, haplotype sharing (HS) was reported as a good alternative method to evaluate variation among populations. HS interrogates the entire genotyping without estimating haplotype block, making it computational efficient, yet retaining population profile. Adopting HS technique and introducing a new haplotype encoding as the input to ipPCA to perform population clustering can yield very good outcomes. Results In this study we transformed an indigenous Thai SNP genotyping data, obtained from Pan Asian SNP consortium, into encoded haplotype profiles. The dataset include 13 indigenous populations (245 individuals) composing of approximately 54K SNPs for each individual. To do this, an encoded haplotype matrix was constructed by inferring overlapping haplotype based on sliding window approach in BEAGLE, an efficient haplotype inference tool. We fed this encoded haplotype matrix to ipPCA to cluster these individuals into sub-groups using only their genetic profiles. We compared the results obtained from standard protocol of ipPCA with the one that use the encoded haplotype matrix in terms of numbers of clustered subpopulations as well as the accuracy to correctly assign an individual to a correct subpopulation. Using the encoded haplotype matrix as input to ipPCA rendered the exact 13 subpopulations to be clustered with 99.18% of individual assignment accuracy, whereas the conventional ipPCA identified only 10 subpopulations with 93.47% of individual assignment accuracy. Conclusions Our result demonstrated the great potential of using the encoded haplotype matrix with ipPCA for population genetics studies. This new protocol can promote the clustering of individuals using only their genetic profiles. [less ▲]

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See detailCarbon nanotube synthesis by CCVD process: kinetic study on a Ni-Mo/MgO catalyst
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

Poster (2012, October)

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See detailCumulative time in band: glycemic level, variability and patient outcome vs. mortality
Penning, Sophie ULg; Signal, Matthew; Preiser, Jean-Charles et al

Poster (2012, October)

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See detailActivités agricoles familiales dans la ville de Lubumbashi (R.D. Congo)
Kalenga, Hortense; Moula, Nassim ULg; Kashala, Jean-Christophe et al

Poster (2012, October)

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See detailExpression et localisation spatio-temporelle de KISS1 et de son récepteur KISSR dans le placenta normal et pathologique.
VALDES SOCIN, Hernan Gonzalo ULg; Munaut, Carine ULg; CHAVEZ, Viviana ULg et al

Poster (2012, October)

Objectif : Etudier l’expression de KISS1 (métastatine) et de son récepteur KISS1R lors de la grossesse normale et pathologique. Matériels et méthodes : Nous avons étudié la localisation de KISS1 et KISS1R ... [more ▼]

Objectif : Etudier l’expression de KISS1 (métastatine) et de son récepteur KISS1R lors de la grossesse normale et pathologique. Matériels et méthodes : Nous avons étudié la localisation de KISS1 et KISS1R par immunohistochimie dans des placentas normaux (1 er et 3 ème trimestre). Par RT-PCR quantitative, nous avons évalué le niveau d’expression des ARNm dans les placentas et les lits placentaires correspondants. Les niveaux d’expression de ARNm ont été comparés entre les grossesses normales (GN, n=13) et les grossesses spathologiques Prééclampsiques -PE-, n=17 et retard de croissance intrautérine -RCIU-, n=9). Résultats : Au premier trimestre des GN, KISS1 est majoritairement localisé dans les syncitiotrophoblastes, alors que KISS1R est détecté dans le mesenchyme villositaire. Au cours du troisième trimestre, KISS1 est uniquement localisé dans le syncitiotrophoblaste au contact avec la décidue et dans le mésenchyme villositaire et KISS1R est détecté dans le trophoblaste extra-villeux ainsi que dans quelques cellules de la décidue. Les analyses par RT-PCR mettent en évidence une expression plus importante des ARNm de KISS1 (p<0,001) et de KISS1R (p=0.039) dans les placentas (GN,PE et RCIU) par rapport aux lits placentaires correspondants. Les niveaux d’expression de KISS1 et KISS1R ne sont pas, cependant, significativement modulés dans les grossesses pathologiques. Conclusions : Par immunohistochimie, nos résultats indiquent une expression spatiotemporelle différente pour KISS1 et KISS1R entre le 1 er et 3 ème trimestre des grossesses normales. Nous n’avons pas mis en évidence de modulation de l’expression des ARNm dans les grossesses pathologiques. [less ▲]

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See detailNumerical modelling of an in situ ventilation test in Callovo-Oxfordian claystone
Pardoen, Benoît ULg; Talandier, J.; Charlier, Robert ULg et al

Poster (2012, October)

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See detailOverview of animal related-accidents in one of the world’s densest road network region
Lehaire, François ULg; Morelle, Kevin ULg; Lejeune, Philippe ULg et al

Poster (2012, October)

With its 4.7 km/km² of public roads, Southern Belgium (Wallonia) has one of the densest road network of Western Europe. This network as well as the observed increase in main game species populations (red ... [more ▼]

With its 4.7 km/km² of public roads, Southern Belgium (Wallonia) has one of the densest road network of Western Europe. This network as well as the observed increase in main game species populations (red deer, roe deer and wild boar) make Wallonia an interesting region for studying the patterns of traffic accidents caused by animals. Moreover, compared to most of European countries, no statistics are available for this area. To shed light on the current situation of wildlife roadkills, the police database of traffic accident statement was thoroughly investigated. Those statements concern accidents that occurred between 2006 and 2010. Each record includes date, time, species involved and information about the location of the accident event. Based on this dataset, we have analysed (i) composition and percentage of involved species, (ii) the consequence (material damages / bodily injuries), (iii) the spatial (type of roads, proximity to landscape features, ‘hot spot’ map) and (iv) temporal (daily, weekly and seasonal) distribution of animal-related accidents. In conclusion future research perspectives are presented. [less ▲]

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See detailTADAM Traitement Assisté par DiAcétylMorphine: Profil des patients
Deblire, Clémence; Demaret, Isabelle ULg; Lemaître, André ULg

Poster (2012, October)

Background : TADAM est une étude contrôlée randomisée comparant un traitement par héroïne (HAT) avec des traitements par méthadone existants. Ce projet est toujours en cours mais nous disposons déjà de ... [more ▼]

Background : TADAM est une étude contrôlée randomisée comparant un traitement par héroïne (HAT) avec des traitements par méthadone existants. Ce projet est toujours en cours mais nous disposons déjà de données sur les patients au moment de leur inclusion. Nous analysons leur profil, particulièrement leurs caractéristiques criminologiques, et nous le comparons avec celui des participants aux autres expériences HAT. Méthodologie : Lors de l’inclusion, chaque patient a répondu à des questionnaires standardisés ainsi qu’à un questionnaire de délinquance et de victimisation auto-rapportées. Comme point de comparaison, nous avons sélectionné trois études européennes contrôlées randomisées sur le HAT. Nous avons ajouté une étude suisse, sans groupe contrôle, évaluant les effets de la prescription d’héroïne sur la délinquance des patients. Résultats : Nos patients sont plus âgés et plus souvent de sexe masculin. Ils bénéficient plus souvent d’allocations sociales et ont connu plus de traitements pour un problème d'addiction. Ces patients avaient un passé judiciaire aussi important qu’à l’étranger. Sur les six derniers mois, ils sont moins nombreux à avoir commis des actes délinquants mais le nombre d'actes commis est plus important. Les faits sont surtout liés à la drogue ou à la propriété. Conclusion : Nos patients étaient moins nombreux à être délinquants mais il y aurait plus de professionnalisation qu'à l'étranger. Le plus petit nombre de délinquants pourrait s'expliquer par la moyenne d'âge plus élevée de nos patients, la plus grande proportion d'allocataires sociaux ou encore par le recours plus important à des traitements pour leur(s) addiction(s). [less ▲]

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See detailMorphological and morphometric analyses of the suspensory ligament in Standardbreds
Shikh Al Sook, Mohamad Khir ULg; Antoine, Nadine ULg; Piret, Joëlle ULg et al

Poster (2012, October)

Ultrasound techniques allow examination of some parts of the suspensory ligament (SL) but "anomalies" are regularly observed. Their significance is not known. Few studies have described the relationship ... [more ▼]

Ultrasound techniques allow examination of some parts of the suspensory ligament (SL) but "anomalies" are regularly observed. Their significance is not known. Few studies have described the relationship between ultrasonographic appearance and the exact morphology in histological sections. The aim of this study is to develop good techniques for cutting, staining, and showing the variation in the tissue composition within the SL. The SLs from the right limbs of 11 horses were collected. Samples were taken from cross-sections at six levels of the SL and they were embedded in paraffin or in Tissue-Tek®. Most of the paraffin sections were shredded. By using the cryosection technique, some freezing artifacts (holes) appeared. Therefore, a technique of freezing with cryoprotection was carried out, which produced the best results. Hematoxylin-phloxine-saffron gives a good contrast of colors between the tissues observed allowing the use of an image analysis program. The percentage of each tissue within the SL for each section and for six levels of the ligament was calculated. Results were analyzed by SAS software. The muscle tissue (PMT) and adipose tissue (PAT) decreased significantly (p < 0.0001), whereas the connective tissue (PCT) increased significantly (p < 0.0001) with age and when descending from the proximal to the distal level of the SL. The PMT was significantly higher (p < 0.0001) in females than males, while the PCT was significantly higher (p < 0.0001) in males than females. The PAT was significantly higher (p = 0.0278) in hindlimbs than in forelimbs. [less ▲]

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See detailAdsorption du bleu de méthylène sur des xérogels de carbone activés
Páez Martínez, Carlos ULg; Contreras, Soledad; Léonard, Angélique ULg et al

Poster (2012, October)

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See detailThe relationships between anomia and short-term memory deficits
Verhaegen, Clémence ULg; Poncelet, Martine ULg

Poster (2012, October)

Anomia is the most common symptom of language dysfunction occurring in aphasia. Moreover, verbal short-term memory (STM) impairments are a frequent characteristic of aphasic syndromes. However, the nature ... [more ▼]

Anomia is the most common symptom of language dysfunction occurring in aphasia. Moreover, verbal short-term memory (STM) impairments are a frequent characteristic of aphasic syndromes. However, the nature of these deficits and their relationships to language production impairments in these patients are still debated. Recent STM models have been proposed incorporating relationships between language representations and STM, including distinct capacities for temporary storage of phonological and lexical-semantic information (N. Martin & Saffran, 1992; R. Martin, Lesch, & Bartha, 1999). This study explores the relationships between anomia and STM deficits. We assume that a naming impairment may be related to either a phonological STM impairment with preserved lexical-semantic STM or to an impaired lexical-semantic STM with preserved phonological STM. We tested these predictions in two aphasic patients, BN and TM. Phonological STM was assessed using a rhyme-probe task (R. Martin et al., 1999) and a lexical-decision task, each target word being preceded by a phonologically related prime word. Lexical-semantic STM was assessed by a category-probe task and a lexical-decision task with semantically related primes. BN was impaired on the rhyme-probe task and presented a reversed phonological priming effect, suggesting phonological STM impairment. However, she presented normal performance on the category-probe task and a normal semantic priming effect. By contrast, TM performed normally on the rhyme-probe and phonological lexical-decision tasks but was impaired on the category-probe task and presented no semantic priming effect, indicating lexical-semantic STM impairment. Moreover, both patients’ word retrieval capacity, as assessed with a picture naming task, was impaired. BN produced phonological paraphasias, repetitive self-corrections and presented an increased length effect. We assume that BN’s errors and effects may be related to her phonological STM deficit. TM instead produced semantic paraphasias, omissions and circumlocutions and presented an increased frequency effect. These errors and effects may be related to his lexical-semantic STM deficit. Results show a double dissociation between phonological and lexical-semantic STM deficits. Furthermore, the patients’ naming patterns seem to indicate that their naming impairment may be related to a selective STM deficit. The results are discussed within the STM framework of N. Martin and Saffran (1992). Martin, N., & Saffran, E. (1992). A computational account of deep dysphasia: evidence from a single case study. Brain and Language, 43(1), 240-274. Martin, R. C., Lesch, M. F., & Bartha, M. C. (1999). Independence of input and output phonology in word processing and short-term memory. Journal of Memory and Language, 41(1), 3-29. [less ▲]

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See detailTan Spot on winter wheat in the Grand Duchy of Luxembourg: Diagnostics and Evolution
El Jarroudi, Moussa ULg; Kouadio, Louis; Beyer, Marco et al

Poster (2012, October)

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See detailRestoration Of B Cells Correlates With Clinical Response To Anti-Tnf Therapy
Li, Z; Vermeire, S; Bullens, D et al

Poster (2012, October)

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See detail1RM PREDICTION AND LOAD-VELOCITY RELATIONSHIP
Jidovtseff, Boris ULg; Cronin, John; Villaret, Jérémy et al

Poster (2012, October)

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See detailCollaborative care in the addiction management of alcohol, illicit drugs and hypnotics and tranquilizers in the Belgian working population
Van Royen, Kathleen; Remmen, Roy; Vanmeerbeek, Marc ULg et al

Poster (2012, October)

Background: General practitioners (GPs) and occupational physicians (OPs) play an important role in detecting and managing substance abuse in the working population. Their collaboration is critical in ... [more ▼]

Background: General practitioners (GPs) and occupational physicians (OPs) play an important role in detecting and managing substance abuse in the working population. Their collaboration is critical in coordinating care, facilitate a quicker rehabilitation and shorten sickleave. A systematic literature search was performed according to the ADAPTE-framework to explore if guidelines exist for collaboration between GPs and OPs in substance abuse management. Method: International guidelines regarding collaborative care for alcohol abuse, illicit drug use and hypnotics and tranquilizers were identified by a detailed systematic search in the Guidelines International Network (GIN) and US National Guidelines Clearinghouse (NGC) databases. Results: In total 20 guidelines were considered of sufficient methodological quality, based on criteria of the Appraisal of Guidelines for Research and Education (AGREE) II instrument. Two out of 20 eligible guidelines reported on the role of OPs. There is a lack of adequate evidence on the role of the OP in substance abuse management. No practical avenues for collaboration between GPs and OPs in the management of substance abuse were suggested. Conclusions: In order to ensure adequate substance abuse management, collaborative models for general practice and occupational health should be developed. We recommend to study pros and cons for collaboration as well as the best way to achieve it. [less ▲]

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See detailStudy of the Boettcher cells along their development: Junctions and expression of the urea-transporter B (UT-B)
Cloes, Marie ULg; Renson, Thomas; Johnen, Nicolas ULg et al

Poster (2012, September 30)

The Boettcher cells (BC) lie on the sensory epithelium of the cochlea. Their function has never been clearly defined. However it has been suggested that they may influence the ionic composition of the ... [more ▼]

The Boettcher cells (BC) lie on the sensory epithelium of the cochlea. Their function has never been clearly defined. However it has been suggested that they may influence the ionic composition of the fluids of the inner ear, which play a central role in the conduction of the sensory information. In this context the compartimentating function of the BC around and after the onset of hearing may influence the subsequent refining of hearing. We collected ultrastructural and immunohistological data during the final maturation stage of the sensory epithelium. In particular the cell junctions were investigated to clarify the compartimentating function of the BC at early stages. As a potential actor in the ion flow in the sensory epithelium, the urea transporter-B (UT-B) was also immunolocalised during the development of the BC. At the mature stage (P25) the BC are linked to the adjacent cells by numerous adherens and non-adherens junctions. They rest on a basilar membrane to which they are attached by hemidesmosomes. They typically exhibit large basolateral interdigitations. We found that, at the 8th postnatal day, the BC are separated from the neighbouring cells by wide spaces entered by scarce cytoplasmic extensions. These spaces are interrupted by areas of close contact, where adherens and non-adherens junctions may be found. Thus, although there seems to be fewer interdigitations at P8, gap junctions probably still allow easy cell-to-cell exchanges. Moreover non-adherens junctions can systematically be identified apically. Although it was impossible to differenciate tight and gap junctions without specific labeling, we postulate that these non-adherens junctions correspond to tight junctions and seal the apex of the BC. This feature is necessary to enable the control of the ion concentrations surrounding the sensory epithelium. We also found that UT-B, known for water and urea transport in red blood cells, is present in the membranes of the BC from P12 (the earliest stage tested) to P25. Thus UT-B may play a role in the regulation of the ionic concentrations of the inner ear fluids. [less ▲]

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See detailPostoperative bleeding and autotransfusion
ERPICUM, Marie ULg; BLAFFART, Francine ULg; DEFRAIGNE, Jean ULg et al

Poster (2012, September 29)

Introduction: Bleeding in the postoperative period of cardiac surgery is not infrequent. Mediastinal bleeding is usually collected in a chest drainage system and discarded. Nevertheless, this blood could ... [more ▼]

Introduction: Bleeding in the postoperative period of cardiac surgery is not infrequent. Mediastinal bleeding is usually collected in a chest drainage system and discarded. Nevertheless, this blood could potentially be managed with a cell salvage device during the first six postoperative hours. This practice is generally performed only in case of a surgical re-exploration for massive bleeding and may contribute to decreased allogeneic transfusion. But in case of postoperative coagulopathy requiring medical treatment, re-exploration is usually postponed and consequently, collected blood is discarded. Therefore, chest drainage systems combined with a cell salvage option could optimize the management of blood losses and transfusions in the postoperative period, regardless of any surgical re-exploration. The aim of this study is to assess the effectiveness of such a system during the postoperative period of cardiac surgery, in patient at high risk of bleeding. Method : During a 6 months period, the CardioPAT® (Haemonetics) device was used in all cardiac surgery patients at high risk of postoperative bleeding. The following data were prospectively collected: hemoglobin level, bleeding volume, volume of autologous washed red blood cell transfused by the CardioPAT® (WRBC), volume of allogeneic red blood cell (RBC), fresh frozen plasma (FFP) or platelets (PT) transfused and surgical re-exploration. Results : The CardioPAT® was used in 16 patients during the target period. Mean postoperative bleeding volume was 338±337mL after 1 hour and 820±727mL after 6 hours. The cell salvage option was used in 9 (56%) cases and mean WRBC transfused volume was 153±212mL. One patient required surgical re-exploration. All patients transfused by WRBC received previously an allogeneic transfusion (RBC, FFP and/or PT). The hemoglobin level of blood collected in the CardioPAT® device impacted on the delay and the blood volume required for WRBC availability; lower was the hemoglobin level, larger was the volume of blood required to obtain a concentrate of WRBC. Consequently, patients with a very low hemoglobin level were anyway transfused with RBC. Conclusion : The CardioPAT® device can reduce allogeneic blood transfusion after cardiac surgery in patients at high risk of bleeding. It gives time to treat coagulopathy, leading to a decrease of surgical re-exploration. However, a device with a larger reservoir and with a flexible processing speed would be more accurate in case of major haemorrhage. Systematic utilisation of this device at the time of FFP and/or PT transfusion is a safe but expensive strategy. It seems more accurate to use this device in a permissive bleeding strategy, waiting for the spontaneous coagulation recovery of the patient, in the first postoperative hours. [less ▲]

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See detailMultimodality blood conservation strategy in cardiac surgery with cardiopulmonary bypass : the CHU of Liège experience
ERPICUM, Marie ULg; BLAFFART, Francine ULg; DEFRAIGNE, Jean ULg et al

Poster (2012, September 29)

Introduction: The aim of this study is to analyze the transfusion rates of cardiac surgery patients in a single centre following an in-house strategy of blood conservation. Methods: The data of all adult ... [more ▼]

Introduction: The aim of this study is to analyze the transfusion rates of cardiac surgery patients in a single centre following an in-house strategy of blood conservation. Methods: The data of all adult patients undergoing normothermic cardiac surgery with cardiopulmonary bypass (CPB) over a 1 year period were retrospectively collected (n=491). Management protocols were described. The transfusion rates of allogeneic blood components were recorded: red blood cells (RBC), fresh frozen plasma (FFP) and platelets (PT), as well as the number of units transfused. The timing of transfusion was categorized: during CPB (peroperative period), within the first 48 postoperative hours after wean out CPB (early postoperative period) and during the hospitalisation from surgery until discharge (hospitalisation). The hematocrit values were recorded during CPB, 10 minutes after wean out CPB, after the first 48 postoperative hours and at discharge from hospital. Results: Two hundred and forty-eight patients (50%) received an allogeneic blood component transfusion during hospitalisation. One hundred and twenty-one patients (25%) received RBC during the operative period; the median of units transfused was 2(1-2).The lowest hematocrit value during CPB was 21(19-24) % in median. A cell salvage device was used in each case: the median volume of washed red blood cells transfused was 678(512-891) mL. The median hematocrit value after CPB was 23(21-25) %. One hundred and sixty-five patients (34%) were transfused in the early postoperative period: 27% received RBC, 18% received FFP and 18% received PT. The median of units transfused was 2(1-3) for RBC, 4(2-6) for FFP and 1(1-2) for PT. The median hematocrit value after 48 hours was 32(29-34) % and 32(30-35) % at discharge. Conclusion: The transfusion rates observed in this series are relatively high compared with the literature. Improvements will be made in our practice and protocols management in order to decrease the need of transfusion. This detailed audit of the transfusion practices in our cardiac surgery centre would be helpful to value the effectiveness of further improvements. [less ▲]

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See detailAuroral counterpart of magnet ic dipolarizations in Saturn’s tail
Jackman, Caitriona; Achilleos, Nicholas; Cowley, Stan et al

Poster (2012, September 27)

Following magnetic reconnection in a planetary magnetotail, newly closed field lines can be rapidly accelerated back towards the planet, becoming “dipolarized” in the process. At Saturn, dipolarizations ... [more ▼]

Following magnetic reconnection in a planetary magnetotail, newly closed field lines can be rapidly accelerated back towards the planet, becoming “dipolarized” in the process. At Saturn, dipolarizations are initially identified in magnetometer data by looking for a southward turning of the magnetic field, indicating the transition from a radially stretched configuration to a more dipolar field topology. The highly stretched geometry of the kronian magnetotail lobes gives rise to a tail current which flows eastward (dusk to dawn) in the near equatorial plane across the centre of the tail. During reconnection and associated dipolarization of the field, the inner edge of this tail current can be diverted through the ionosphere, in a situation analogous to the substorm current wedge picture at Earth. We present a picture of the current circuit arising from this tail reconfiguration, and outline the equations which govern the field- current relationship. We show the first in situ example of a dipolarization identified in the Cassini magnetometer data and use this formalism to estimate the ionospheric current density that would arise for this example and the implications for auroral electron acceleration in regions of upward directed field-aligned current. We then present a separate example of data from the Cassini UVIS instrument where we observe small ‘spots’ of auroral emission lying near the main oval; features suggested to be associated with dipolarizations in the tail. In the example shown, such auroral features are the precursor to more intense activity associated with recurrent energisation via particle injections from the tail following reconnection. [less ▲]

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See detailHuman papillomavirus capsids trigger crosstalk between dendritic and NK cells
Langers, Inge ULg; Renoux, Virginie; Pirotte, Evelyne et al

Poster (2012, September 26)

The immune system controls, at least partially, human papillomavirus (HPV) infection and subsequent tumour development as demonstrated by a higher tumour prevalence in immunodeficient patients. More than ... [more ▼]

The immune system controls, at least partially, human papillomavirus (HPV) infection and subsequent tumour development as demonstrated by a higher tumour prevalence in immunodeficient patients. More than 90% of HPV-infected women will clear the virus within two years. However, it remains unclear which immune cells are implicated in this process and although dendritic cells (DC) and NK cells play a key role in host resistance to virus and tumour, no study has been performed evaluating their crosstalk in this context. Virus-like particles (VLP) formed by the HPV major capsid protein L1 are licensed as vaccine against cervical cancer and we have recently shown that NK cells can directly interact with these HPV-VLP [1]. Here, we investigated the impact of this activation on NK-DC crosstalk. Interestingly, NK cells increase DC maturation induced by HPV-VLP as shown by an up-regulation of HLA-DR and CD86 on DC. Transwell experiments indicated that the expression of HLA-DR is cell-cell contact and soluble factor dependent, whereas only soluble factors seem to be required for CD86 expression. Moreover, in the presence of HPV-VLP and NK cells, DC produce higher amounts of IL12p70, while the production of the immunosuppressive cytokine IL10 remains unchanged. We also demonstrated that DC can up-regulate the expression of NK activation markers (CD69 and HLA-DR) in the presence of HPV-VLP. This up-regulation requires both cell-cell contact and soluble factors. Regarding HLA-DR marker, the increased expression on CD56bright cells is mediated by soluble factors, whereas cell-cell contacts are also important for HLA-DR expression on CD56dim cells. In the presence of DC activated by HPV-VLP, the function of NK cells is also modified since they become more cytotoxic against HPV+ cell line and secrete more IFN-γ. Our results suggest that NK-DC crosstalk could play a role in the immune response induced by HPV-VLP during vaccination protocols against cervical cancer. [less ▲]

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See detailThe Rain Ratio Hypothesis Revisited
Munhoven, Guy ULg

Poster (2012, September 21)

The Rain Ratio Hypothesis (Archer and Maier-Reimer, 1994, Nature 367, 260–263) ascribes an important part of the observed glacial-interglacial variations of CO2 in the atmosphere to reduced sea-floor rain ... [more ▼]

The Rain Ratio Hypothesis (Archer and Maier-Reimer, 1994, Nature 367, 260–263) ascribes an important part of the observed glacial-interglacial variations of CO2 in the atmosphere to reduced sea-floor rain ratio (i.e., carbonate-C/organic-C in the biogenic particle flux at the sea-floor) during glacial times. With a lower sea-floor rain ratio the influence of organic carbon respiration on carbonate dissolution is stronger. The deep-sea carbonate ion concentration required for global ocean carbonate compensation will then be higher, which in turn contributes to lower atmospheric pCO2. Munhoven (2007, Deep-Sea Research II, 722–746) showed that the suggested rain ratio reductions lead to unrealistic sedimentary records for %CaCO3: the transition zone changes in the model sedimentary record were too large and opposite in phase to available observational data. The rain ratio reduction applied by Munhoven (2007) was uniform over the ocean and the author hypothesised that a non-uniform reduction could change the complete picture. If the rain ratio variations had primarily taken place in open ocean areas of great depth—essentially in regions where the sea floor was deeper than the saturation horizon or the CCD—then the transition zone boundaries could possibly have moved less. Here, we test this hypothesis and analyse the effect of depth dependent variations. We find that concentrating rain ratio changes over areas of great water depth completely alters the sedimentary imprint: the phase relationship of the signal reverts (compared to the uniform case) and the amplitude of the change decreases, bringing it into better agreement with available observations. However, the global average rain ratio reduction of 40% that yielded a 40 ppm reduction of atmospheric pCO2 in the uniform case only leads to 25 ppm in this non-uniform case. [less ▲]

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See detailObservance au traitement par CPAP chez les patients souffrant d’apnées du sommeil
DEFLANDRE, Eric; DEGEY, Stéphanie; BONHOMME, Vincent ULg et al

Poster (2012, September 20)

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See detailDiffuse urban and industrial groundwater pollution with metallic trace elements: a comparison between affected and unaffected areas
Gesels, Julie ULg; Dollé, Fabien ULg; Leclercq, Julie et al

Poster (2012, September 20)

For metalic trace elements, spatially distributed background concentrations will be defined as a function of geological and hydrogeological context and considering the impact of diffuse pollution.

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See detailPromoter analysis of three HMA4 gene copies in the zinc hyperaccumulator Arabidopsis halleri
Nouet, Cécile ULg; Cebula, Justyna; Motte, Patrick ULg et al

Poster (2012, September 20)

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See detailAlginate-chitosan hydrogel beads decrease inflammatory and anabolic mediators produced by human chondrocytes
Oprenyeszk, Frédéric ULg; Sanchez, Christelle ULg; Dubuc, Jean-Emile et al

Poster (2012, September 17)

Introduction Osteoarthritis (OA) is the most prevalent arthritic disease. It is characterized by the degradation of articular cartilage accompanied by the inflammation of the synovial membrane and ... [more ▼]

Introduction Osteoarthritis (OA) is the most prevalent arthritic disease. It is characterized by the degradation of articular cartilage accompanied by the inflammation of the synovial membrane and sclerosis of subchondral bone. OA produces pain and loss of joint function. Today, there is no treatment to cure OA or to delay effectively its progression. Current treatments are mainly based on alleviation of painful symptoms but are unable to restore the cartilage. The development of new scaffold for tissue engineering is a promising approach. Herein, we report the effects of alginate-chitosan hydrogel (AC) beads on the metabolism of chondrocytes. Materials and Methods Human chondrocytes were isolated from OA cartilage and cultured either in AC beads or in alginate (A) beads. AC beads were prepared using chitosan (KiOmedine-CsU ultra-pure chitosan from KitoZyme, Herstal, Belgium) and alginate. The two polymer solutions were prepared separately before being mixed together. Cells were added to the polymer mixture and the cell-containing beads prepared by precipitation in a calcium chloride solution. The chondrocytes embedded in the beads were then cultured in a well defined culture medium for up to 28 days. Cell viability was determined by quantifying the release of lactate deshydrogenase (LDH) in the culture supernatant. Interleukin (IL)-6 and -8, prostaglandin E2 (PGE2), matrix metalloprotease (MMP)-3 and aggrecan were measured by specific ELISA. Finally, nitric oxide (NO) was measured by the Griess reaction. Results Histological analysis of AC beads showed chondrocytes in contact with chitosan trabeculae that were homogeneously distributed in the alginate matrix. LDH level remained below the limit of detection over the culture duration suggesting that AC had no cytotoxic effect. By comparison with culture in A beads, chondrocytes in AC beads produced significantly higher amounts of aggrecan but lowered the levels of MMP-3, NO, IL-6, IL-8 and PGE2. Discussion The contact between cells and AC beads components led us to hypothesize that chitosan has beneficial effects such as anti-inflammatory, anti-catabolic and stimulating effects on cartilage matrix components. Conclusion These particular effects indicate that AC beads are potentially new carriers for cell transplantation, particularly to repair cartilage defects. They could be further developed under various formulations, such as microbeads in combination with hydrogel for efficient viscossuplementation. [less ▲]

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See detailMultiscale modeling of in the influence of oxygen during bone fracture healing.
Carlier, Aurélie ULg; Van Gastel, Nick; Carmeliet, Geert et al

Poster (2012, September 17)

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See detailNORS: Demonstration Network Of ground-based Remote Sensing observations in support of the GMES atmospheric service
De Mazière, M; Hocke, K; Richter, A et al

Poster (2012, September 17)

NORS (Demonstration Network Of ground-based Remote Sensing Observations in support of the GMES Atmospheric Service) aims at demonstrating the value of ground – based remote sensing data from the Network ... [more ▼]

NORS (Demonstration Network Of ground-based Remote Sensing Observations in support of the GMES Atmospheric Service) aims at demonstrating the value of ground – based remote sensing data from the Network for the Detection of Atmospheric Composition Change for quality assessment and improvement of the GMES Atmospheric Service products. [less ▲]

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See detailIntraocular Lens Adsorbome: a Proteomic Study of Adsorbed Proteins onto Acrylic Materials and Its Implication in Secondary Cataract
Huang, Yi-Shiang ULg; Bertrand, Virginie ULg; Mazzucchelli, Gabriel ULg et al

Poster (2012, September 17)

The intraocular lens (IOL) is a polymer implant designed to replace the natural lens after cataract surgery. When the implant is introduced into the lens capsule, the polymer starts to interact with the ... [more ▼]

The intraocular lens (IOL) is a polymer implant designed to replace the natural lens after cataract surgery. When the implant is introduced into the lens capsule, the polymer starts to interact with the aqueous humour and the exchange of molecules between the solid and the liquid begins. The nature of exchange in water, ions, and biomolecules may result in several postoperative complications including glistening, calcification, and posterior capsular opacification. The posterior capsular opacification (PCO, also called “Secondary Cataract”) is raised from the over-growth of residual lens epithelial cells. The first step of the over-growth process of the cells is their adhesion to the deposited biomolecules, such as proteins involved in extra-cellular matrices. The purpose of this study is to identify the principal proteins adsorbed onto the acrylic polymers by mass spectrometry. The concept of adsorbome is to generate a list of adsorbed proteins to the hydrophilic and hydrophobic polymers, and then compare the difference to the original component of aqueous humour in order to see the affinity of individual protein to each material. Two kinds of hydrophilic and two kinds of hydrophobic acrylic polymers were tested for their adsorbomes by treating them with an aqueous humour analogue and the major adsorbed proteins were identified by mass spectrometry. Interestingly, the hydrophilic acrylic polymer shows a relative lower protein adsorption rate but shows a higher incidence of secondary cataract. This phenomenon implies the adsorbed proteins play a crucial role in progress of secondary cataract. [less ▲]

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See detailStimuli-responsive Magnetic Nanohybrids for Triggered Drug Release and Potential Tumor Treatment via Hyperthermia
Liu, Ji ULg; Detrembleur, Christophe ULg; Mornet, Stéphane et al

Poster (2012, September 13)

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See detailSick leave due to low back pain in a cohort of young workers in Belgium
VAN NIEUWENHUYSE, AN; BURDORF, Alex; CROMBEZ, Geert et al

Poster (2012, September 13)

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See detailA climate model from 200 AD to 1200 AD for the Hautes-Fagnes plateau (East Belgium) : based on pollen grains, testate amoebae, and humification analyses
Beghin, Jérémie ULg; Fagel, Nathalie ULg; Gerrienne, Philippe ULg et al

Poster (2012, September 12)

Several peat cores were extracted from the Misten bog, on the Hautes-Fagnes plateau (East Belgium). Analyses of pollen grains, testate amoebae and the degree of peat humification have been standardised ... [more ▼]

Several peat cores were extracted from the Misten bog, on the Hautes-Fagnes plateau (East Belgium). Analyses of pollen grains, testate amoebae and the degree of peat humification have been standardised and combined into a palaeo-hydro-climatic model from 200 AD to 1200 AD. The reconstruction shows 9 distinctive phases of near-surface water tables, which may be used to infer changes in the atmospheric water balance of eastern Belgium during the Subatlantic stage. [less ▲]

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See detailNeutralising properties of peptides derived from CXCR4 extracellular loops towards CXCL12 binding towards both CXCR4 and CXCR7
Szpakowska, Martyna ULg; Deroo, Sabrina; Schmit, Jean-Claude et al

Poster (2012, September 12)

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See detailCreation of a Canopy Height Model from mini-UAV Imagery
Lisein, Jonathan ULg; Bonnet, Stéphanie ULg; Lejeune, Philippe ULg

Poster (2012, September 12)

The arrival of mini-UAV (Unmanned Aerial Vehicle), these small autonomous aircrafts, has opened the doors to a new environmental data acquisition’s approach. In forestry, low-altitude imagery from UAV can ... [more ▼]

The arrival of mini-UAV (Unmanned Aerial Vehicle), these small autonomous aircrafts, has opened the doors to a new environmental data acquisition’s approach. In forestry, low-altitude imagery from UAV can be used to characterize forest ecosystem structure through a Canopy Height Model (CHM). In this research, authors developed a new workflow for acquiring low-altitude aerial images with a mini-UAV and used them for the construction of a high resolution Canopy Height Model. An accuracy analysis is performed and shows that individual dominant tree height can be measured from (UAV-photo-) CHM with a precision of 2 meters. [less ▲]

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See detailGeomatallurgical approach and quantitative mineralogy of the Copper/gold deposit of Chelopech
Evrard, Maxime ULg; Pirard, Eric ULg

Poster (2012, September 11)

The Chelopech gold-copper mine is localized in the western part of Bulgaria and is one of the largest gold producer in Europe.An image processing method is applied on different flotation plant samples ... [more ▼]

The Chelopech gold-copper mine is localized in the western part of Bulgaria and is one of the largest gold producer in Europe.An image processing method is applied on different flotation plant samples: ore after milling, tailings 1; tailings 2, total tailings and concentrate. Polished sections made with these samples are analyzed in order to quantify the mineral amounts in each sample. The purpose of this quantitative analysis is to know the nature and proportions of mineral phases at each stage of the process. This study allow to know in which forms copper, arsenic and trace elements are present in the different samples and to track them during the different stages, which is very relevant information in order to improve ore treatment and tailings management. [less ▲]

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See detailReplacing explicit water and lipids by implicit representation in molecular dynamics simulations
Steinhauer, Sven ULg; Crowet, Jean-Marc ULg; Lins, Laurence ULg et al

Poster (2012, September 11)

Molecular dynamics (MD) is an appropriate method for investigation of biomolecular systems and helps in explaining results from wet lab experiments or in getting further insight into details, which are ... [more ▼]

Molecular dynamics (MD) is an appropriate method for investigation of biomolecular systems and helps in explaining results from wet lab experiments or in getting further insight into details, which are not accessible by experimental methods(Lindahl, 2008). By now, many biologically relevant processes for drug design, toxicological studies and other fields of application, can not be performed by atomistic MD simulations (Lindahl, 2008). <br />In MD, the necessary time effort for carrying out a simulation is considerable and depends mainly on (1) the complexity of the simulated system (2) the simulated time scale (3) the simulation method (4) the efficiency of used hardware and software algorithms. Carried out MD simulations nowadays may still take weeks of calculation on high end computers. <br /> <br />In practice, biologically relevant processes, as e.g. protein folding, take usually place above the time scale of milli seconds. They can take up to the order of some thousands of seconds (in case of the folding of membrane proteins). Molecular dynamics computer simulations have reached the scale of micro seconds for simulations of systems where each atom was described and simulated over time.(Lindahl, 2008) <br /> <br />Nevertheless, MD has risen to an important promoter methodology for many different fields of application. By replacing bunches of atoms by artificial particles, complexity of the systems can be reduced. This method is called the coarse grain method (CG). Biggin and Bond (2008) found an acceleration of their simulation processes for self assembling membrane / protein systems in water by factor 100. They estimated one to two days of calculation for a simulated time scale of 0.1 to 0.2 micro seconds for their systems. <br /> <br />Implicit force fields like "IMPALA", aim to describe water and/or membrane molecules in simulations by a couple of simple and partially precalculable equations. “IMPALA” is a force field initially developed by our laboratory. Using this method, thousands of water and lipid molecules can be replaced, leading to a reduced complexity of the system to be simulated. <br />"IMPALA"(Ducarme et al., 1998) based on the assumption of rigid peptides and aimed to find the insertion characteristics of such in membranes. Elimination of the necessity for simulating the aqueous and lipid phase atom by atom in the software package "Gromacs"(Berendsen et al., 1995) will permit both: a gain of speed, as it was already the case for the introduction of the coarse grain method, and a gain of precision by turning rigid molecules flexible through "Gromacs". Our current work is the integration of the "IMPALA" implicit force field into "Gromacs". <br /> <br />Biggin, P.C. & Bond, P.J. Molecular dynamics simulations of membrane proteins. Methods Mol. Biol. 443, 147-60(2008). <br />Berendsen, et al. (1995) Comp. Phys. Comm. 91: 43-56. <br />Ducarme, P., Rahman, M. & Brasseur, R. IMPALA: a simple restraint field to simulate the biological membrane in molecular structure studies. Proteins 30, 357-71(1998). <br />Lindahl, E.R. (2008). Molecular dynamics simulations. Methods Mol. Biol. 443, 3-23. [less ▲]

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See detailDevelopment of optical trajectography device for the lagangian study of turbulent flow inside a stirred tank used in pharmaceutical industry
Collignon, Marie-Laure ULg; Delafosse, Angélique ULg; Delvigne, Frank ULg et al

Poster (2012, September 10)

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly ... [more ▼]

Stirred tanks are devices that are widely used in various process steps of the pharmaceutical industry. The performance of these processes (animal cell culture, crystallization, flocculation …) strongly depend on the physico-chemical and hydrodynamic environment present locally in these tanks. To fully describe this local environment, an Eulerian - Lagrangian approach must be adopted in order to establish history of conditions met by a particle as a cell, a crystal or a floc. This approach implies to determine the trajectory followed by the particle. To this aim, the Chemical Laboratory of Liege University has developed a prototype of optical trajectography device. The objective of this paper is to present the device, developments that were necessary for its use and the results obtained. The device is composed of two cameras modeled by a pinhole model which record the position of a bead that has a size equal to 490 µm and that perfectly follows local flow structures. The measured trajectory has been validated by comparing average time velocity fields deduced from it to those measured, in the same operating conditions, by particle image velocimetry (P.I.V.). [less ▲]

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See detailUse of new surface active carbohydrate esters for the synthesis of polyhipes in supercritical CO2
Boyère, Cédric ULg; Favrelle, Audrey; Grignard, Bruno ULg et al

Poster (2012, September 10)

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See detailInfluence of protein context on the propensity of polyglutamine tracts to trigger protein aggregation into amyloid fibrils
Huynen, Céline ULg

Poster (2012, September 10)

Nine neurodegenerative diseases, referred to as polyglutamine diseases, are associated with nine proteins containing an expanded polyglutamine (polyQ) tract. PolyQ tracts are encoded by a repetition of ... [more ▼]

Nine neurodegenerative diseases, referred to as polyglutamine diseases, are associated with nine proteins containing an expanded polyglutamine (polyQ) tract. PolyQ tracts are encoded by a repetition of the CAG codon in the corresponding genes, and are present in proteins of healthy people. They are however pathogenic when their length, due to mutations, becomes higher than a threshold generally comprised between 35 and 45Q. Such pathological tracts trigger the aggregation of the proteins into amyloid-like aggregates that could play an important role in the disease. It is therefore necessary to investigate at a molecular level the aggregation process of polyQ proteins. Since proteins associated with polyQ diseases are generally large and relatively insoluble, they are difficult to produce and handle experimentally. We have therefore decided to study the aggregation properties of polyQ proteins by designing and characterizing model proteins made of a well-characterized host protein, the β-lactamase BlaP, and polyQ tracts of different lengths (23 to 79Q) inserted either at positions 197 or 216 of BlaP. The aggregation behaviour of BlaP chimeras recapitulate those of proteins associated with polyQ diseases. We indeed observed that there is a minimal number of glutamines (i.e. a threshold) required for the chimeras’ aggregation into amyloid-like fibrils and that the kinetics of aggregation are faster with longer glutamine repeats. Most importantly, the value of the threshold for amyloid-like fibril formation seems to critically depend on the structural integrity of BlaP and thus on the constraints applied to the polyQ tract. In the present work, we investigate more deeply the role of the protein context and of oligomers on the aggregation process of BlaP chimeras. This study is mainly based on the use of two techniques: the quartz crystal microbalance with dissipation (QCM-D) in combination with atomic force microscopy (AFM), and the dynamic light scattering (DLS). QCM-D studies indicate that, under native condition, there is a minimal number of glutamines required for the elongation of BlaP197(Gln)79 fibrils by BlaP chimeras containing a polyQ tract in position 197. This threshold is lower than that observed for the aggregation assays monitored in solution in the absence of seed; it corresponds however to the threshold for fibril formation observed under denaturing conditions. These observations suggest that the conformation of BlaP is the limiting step for amyloid fibril formation by interfering with the nucleation step. BlaP chimeras containing 55Q or more in position 216 of BlaP also elongate BlaP197(Gln)79 fibrils. Interestingly this rate of cross-elongation is faster than the elongation rate observed with BlaP197(Gln)55 and BlaP197(Gln)79. This observation demonstrates that the protein environment of the polyQ tract influences its propensity to form amyloid fibrils. Finally, preliminary DLS experiments indicate that oligomers formed by BlaP197(Gln)79 under native condition are on-pathway of amyloid fibril formation and could act as aggregation nuclei. [less ▲]

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See detailCharacterizing of protein dataset with GO ontology
Dmitrieva, Joelia Borisnova; Florea, B; Li, N et al

Poster (2012, September 09)

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See detailDifference in neural correlates of discrimination during sleep deprivation in PER3 homozygous
Shaffii-Le Bourdiec, Anahita; Muto, Vincenzo ULg; Jaspar, Mathieu ULg et al

Poster (2012, September 07)

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See detailDoes the new water-soluble form of curcumin(NDS27) inhibit the oxidant response of stimulated neutrophils and HL-60 cells?
Derochette, Sandrine ULg; Franck, Thierry ULg; Deby-Dupont, Ginette et al

Poster (2012, September 07)

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) and the release of an oxidant enzyme, myeloperoxidase (MPO), to kill pathologic ... [more ▼]

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) and the release of an oxidant enzyme, myeloperoxidase (MPO), to kill pathologic agents. But, an excessive stimulation of PMNs is associated with development of inflammatory diseases. Neutrophils are prime targets to control inflammatory events and the therapeutic use of polyphenols is proposed to lower oxidative stress. The aim of this work was to study antioxidant effect of NDS27, a water-soluble form of curcumin, on stimulated equine PMNs and human promyelocytic leukemia cells (HL-60) which are less differenciated. 2',7'-Dichlorofluorescin diacetate and lucigenin were used to measure ROS production by activated HL-60 cells or PMNs. NDS27 (10-6 to 10-4 M) was pre-incubated with cells and eliminated before their activation to study its intracellular effects on ROS production. The effect of NDS27 on MPO activity released by the cells was determined by SIEFED. Likewise, the ability of NDS27 to enter into the cells was checked by HPLC on the cellular extracts.NDS27 significantly and dose-dependently inhibited the ROS production in both cell types without affecting their viability. Its intracellular effect showed higher efficiency for PMNs while its interaction with HL-60 cells remained better. The activity of MPO released by PMNs and HL-60 cells was decreased by NDS27 with a more efficient effect for PMNs. Our findings suggest that the greater efficiency of NDS27 in mature PMNs is not due to a better membrane permeability or a better interaction between membrane and NDS27, but rather to an inhibitory effect on the ROS production by the more mature cells, probably by targeting the enzymes implied in respiratory burst like MPO and NADPH oxidase. The modulatory effect of NDS27 towards oxidant activity of cells involved in immune and inflammatory response opens therapeutic perspectives to control pathologies with excessive inflammatory reactions. [less ▲]

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See detailRECOURS À UNE CAMPAGNE DE MESURES TOPOCLIMATIQUES APPLIQUÉE POUR UNE ÉTUDE COMPARATIVE DE VARIABLES MÉTÉOROLOGIQUES CONCOMITANTES PROVENANT DES STATIONS MÉTÉOROLOGIQUES DE BRUGGE ET DU MONT RIGI EN BELGIQUE
Pirard, Xavier ULg; Jorion, Nicolas ULg; Doutreloup, Sébastien ULg et al

Poster (2012, September 07)

Une station météorologique automatique munie d’un mât de 10 mètres a été installée à l’Ouest de l’agglomération urbaine de Brugge (Belgique) par le Laboratoire de Climatologie et Topoclimatologie de l’ULg ... [more ▼]

Une station météorologique automatique munie d’un mât de 10 mètres a été installée à l’Ouest de l’agglomération urbaine de Brugge (Belgique) par le Laboratoire de Climatologie et Topoclimatologie de l’ULg. Elle a été équipée afin de confirmer la bonne qualité des prévisions météorologiques du modèle WRF établies dans le cadre du projet européen TWENTIES. Les données récoltées de minute en minute par cette station météorologique offrent également l’opportunité de mettre en évidence le détail de situations météorologiques bien particulières comme celles correspondant aux passages de fronts. [less ▲]

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See detailIncrease in cortico-thalamo-cortical connectivity during human sleep slow wave activity
Kussé, Caroline ULg; Lehembre, Rémy; Foret, Ariane et al

Poster (2012, September 05)

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See detailEffect of duration and temperature of previous vacuum-packed storage on the microbiological quality of Belgian Blue meat packed in high-oxygen atmosphere
Didimo Imazaki, Pedro Henrique ULg; Tahiri, Assia ULg; Daube, Georges ULg et al

Poster (2012, September 05)

The aim of this experiment was to study the effect of duration and temperature of previous vacuum-packed (VP) storage on the microbiological quality of Belgian Blue (BB) beef packed in high-oxygen ... [more ▼]

The aim of this experiment was to study the effect of duration and temperature of previous vacuum-packed (VP) storage on the microbiological quality of Belgian Blue (BB) beef packed in high-oxygen atmosphere. VP striploins from bulls (B) and cows (C) were stored at −1 °C and +4 °C for up to 80 days. These meats were subsequently repackaged under modified atmosphere (MA) – 70 % O2/30 % CO2 – at different times, and stored 2 d at +4 °C and 5 d at +8 °C. The average initial counts in VP meats were 3.6 log CFU/cm² (B) and 2.7 log CFU/cm² (C) for total viable count (TVC) at +22 °C; < 2.0 log CFU/cm² (B and C) for lactic ac id bacteria (LAB) at +22 °C; 1.1 log CFU/cm² (B) and 1.3 log CFU/cm² (C) for Enterobacteriaceae at +30 °C and < 1.0 log CFU/cm² (B and C) for Pseudomonas spp. and Brochothrix thermosphacta. During the first 40 days of VP storage, temperature had a striking influence on microbial growth. The maximum count differences between storage temperatures were obtained at the 20th day of storage: 2.7 log CFU/cm² (B) and 2.9 log CFU/cm² (C) for TVC, 4.0 log CFU/cm² (B and C) for LAB and 3.6 log CFU/cm² (B and C) for Enterobacteriaceae. The difference in TVC between temperatures at the 20th day tended to disappear once the meats were repacked under MA and stored during seven days. Conversely, the difference in LAB and Enterobacteriaceae counts tended to be maintained after MA repackaging, showing that duration and temperature of VP storage had influence on microbiological quality of BB meat subsequently stored in high-oxygen atmosphere. Moreover, chilling at temperatures very close to the freezing point of meat during VP storage, which has already showed innumerous advantages for physicochemical quality of meat, was capital to maintain the microbiological quality of BB fresh meat during subsequent MA-packed storage. [less ▲]

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See detailMultiscale modeling of sprouting angiogenesis: tip cells are selected for the top.
Carlier, Aurélie ULg; Geris, Liesbet ULg; Van Oosterwyck, Hans

Poster (2012, September 05)

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See detailOrganometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination
Kermagoret, Anthony ULg; Morin, A.; Hurtgen, Marie ULg et al

Poster (2012, September 04)

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See detailIncrease in cortico-thalamo-cortical connectivity during human sleep slow wave activity
Kussé, Caroline ULg; Lehembre, Rémy; Foret, Ariane et al

Poster (2012, September 04)

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See detailMolecular identification of the bacterial populations of steak tartare, a raw consumed meat preparation: a practical use of targeted metagenomic analysis
Taminiau, Bernard ULg; Delhalle, Laurent ULg; Nezer, Carine et al

Poster (2012, September 04)

Steak tartare is a popular meat dish in Belgium and other european countries. It is often consumed with french fries or as sandwich spread. This product, due to its raw nature, is highly sensitive to ... [more ▼]

Steak tartare is a popular meat dish in Belgium and other european countries. It is often consumed with french fries or as sandwich spread. This product, due to its raw nature, is highly sensitive to bacterial alteration. A better understanding of the bacterial content of this meat product will thus be insightful to master the alteration hazards. Throughout a targeted metagenomic analysis we characterized the bacterial populations of several steak tartare samples. These samples were bought and analyzed during the same day, from three different commercial sources: butchery, sandwich vendor and restaurant. A classic microbiological analysis was performed in parallel. The metagenomic analysis was targeted on two different hypervariable regions of the bacterial 16S rDNA, in order to compare the bacterial identification efficiency. A total of 60,500 sequences for 12 samples were submitted to a metagenomic analysis. The best hypervariable region enabled us to identify 356 different bacterial species. Lactobacillus algidus is the leading bacterial species, representing 52% of the total analyzed sequences, followed by an uncultured Pseudomonas sp. (8.43%) and Photobacterium phosphoreum (7.92%). The analysis of the results shows that remarkable differences appear between the three sources of steak tartare. First, the samples from the butchery are mainly composed of Lactobacillus populations and to a lesser extend of environmental contaminants like Xanthomonas campestris. On the opposite, the samples from the restaurant are contaminated with higher level of Leuconostocaceae like Leuconostoc carnosum or an uncultured Weissella sp., or with gamma-proteobacteria like Pseudomonas sp. or Psychrobacter sp. These last samples were characterized with some alteration (slime, off odor) that can thus be put in relation with the bacterial populations identified. Combining a broad-range sequencing effort to a rigorous computer analysis gives a powerful tool for the microbiology of food products. Its application can be virtually extended to every food product be readily transposed to the food industry. [less ▲]

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See detailThe extraordinary potential of metagenomic tools for food microbiology: an example with bacterial microbiota of raw and pasteurized milk cheeses
Delhalle, Laurent ULg; Nezer, Carine; Taminiau, Bernard ULg et al

Poster (2012, September 03)

Among the culture-independent techniques, ultra-sequencing has contributed to place metagenomic analysis as the best alternative to study complex microbiota. During the last three years, metagenomic ... [more ▼]

Among the culture-independent techniques, ultra-sequencing has contributed to place metagenomic analysis as the best alternative to study complex microbiota. During the last three years, metagenomic studies were used essentially for environmental samples but it could be used also to analyse bacterial populations of food samples. This work describes the application of this technique to study the bacterial population of different types of soft cheeses. Among these, three of them are a typical Belgian soft cheese with washed rind (two with raw milk and the third with pasteurized milk). The fourth is a French creamy soft cheese made with raw milk. Classical microbiological and 16S rDNA metagenomic analysis were carried out in the core and on the rind of the four cheeses, giving a total of 8 samples. In total, 48 genus and 163 species were identified for all samples. As expected Lactoccocus lactis and/or cremoris are the most representative species in the core of the four cheeses. On the rind of cheeses, the predominant bacterial species are Psychrobacter glacinola, Staphylococcus equorum, Corynebacterium casei and Marinilactibacillus psychrotolerans. Brevibacterium spp and Psychroflexus spp are important for the rind of washed rind cheeses. All these species are present in different proportions following the origin and the cheese making process and they are well known for their organoleptic properties on the rind of cheese. The two Belgian soft cheese made with raw milk are composed of many more different bacterial species. While the cheese made from pasteurized milk contains less species mainly composed by Lactococcus lactis (97,6%) in the core. An unexpected result is the low diversity of the a French creamy soft cheese made with raw milk with only two predominent species : Lactoccocus cremoris and Leuconostoc citreum are present in the core (94,9% and 4,9% , respectively) and on the rind (93,8% and 5% , respectively). Compared with the other cheeses made with raw milk, this result is surprising. The bacterial cheese microbiota plays a central role in cheese-making. The subtleties of cheese character, as well as their shelf-life, are largely determined by the evolution of their microbiota. [less ▲]

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See detailA new approach of food microbiology with the metagenomic tools: an application on fish
Delhalle, Laurent ULg; Taminiau, Bernard ULg; Nezer, Carine et al

Poster (2012, September 03)

Metagenomics has appeared as a powerful tool to study bacterial composition of various environmental samples. Its interest has started to appear in food microbiology but only on the study of very ... [more ▼]

Metagenomics has appeared as a powerful tool to study bacterial composition of various environmental samples. Its interest has started to appear in food microbiology but only on the study of very particular bacterial populations of fermented food. This work describes the application of this technique to study the bacterial population of two fresh fish filets. The two fish species are from freshwater (pangasius) and seawater (haddock), respectively. Samples where directly analyzed the day of receipt. Others samples were analyzed at the end their shelf life after storage at 4°C (1/3 of their shelf life) and 8°C (2/3 of their shelf life). For these samples, packagings were made in plastic wrap for atmospheric air condition and in trays under modified atmosphere. Classical microbiological and 16S rDNA metagenomic analysis were carried out on all these samples. The composition and evolution of microbial populations of fish filet stored under different packaging conditions and temperatures of storage were investigated with identification of bacteria species. A total of 40 different species were identified for both fish types. Gram-negative bacteria are always predominated among the initial flora and at the end of the shelf life in all the trials. At the beginning of storage, the predominant Gram-negative microflora consisted of Moraxellaceae (Acinetobacter spp, Psychrobacter spp.), Pseudomonadaceae (Pseudomonas spp), and Shewanella spp and the Gram-positive flora was identified as Lactobacillaceae (Carnobacterium spp), Brochothrix thermosphacta and Planococcus donghaensis (only for pangasius). Regardless the packaging and the fish origin, significant variations of the initial flora were noted. The important growth of some Gram negative populations could indicate a risk of spoilage. Thus, the metagenomic approach could be used to adequately determine the duration of shelf-life. For the pangasius, Planococcus donghaensis is only present before the fish is packed and its dominant presence could provide an indication of the freshness of the fish. The metagenomic analysis is a useful tool to identify and to measure the relative proportions of bacterial species in fish filet samples. [less ▲]

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See detailDoes drawing faces make you a super-expert of faces? An investigation of face perception and recognition abilities in visual artists.
Devue, Christel ULg; Barsics, Catherine ULg; Brédart, Serge ULg

Poster (2012, September 01)

Face recognition abilities might constitute a continuum with developmental prosopagnosia and outstanding face recognition capacity at each extreme. 'Super-recognizers' display better face processing ... [more ▼]

Face recognition abilities might constitute a continuum with developmental prosopagnosia and outstanding face recognition capacity at each extreme. 'Super-recognizers' display better face processing abilities than controls and show a larger face inversion effect (FIE) [Russell et al, 2009, Psychonomic Bulletin & Review, 16 (2), 252-257]. Hence, FIE could reflect a specific visual experience/expertise with faces compared to other objects rather than a qualitatively different kind of processing. In this experiment we tested face processing abilities of visual artists who practice portraiture, as well as more general visual perception and recognition skills, in order to contribute to the long-lasting debate about a possible special status of faces. If some special processing faces benefit from is due to expertise, artists' practice might lead to better perceptual and possibly recognition performance with upright faces compared to controls, while increasing the FIE. Because they need to take both configural and featural information into account to reach a satisfactory likeness, artists might also make a differential use of these facial cues compared to controls. Preliminary data indicate that face processing performance might indeed be linked to perceptual expertise with faces. [less ▲]

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See detailStudy of the virulence of african horse sickness virus serotypeS 4 and 9 in two mouse models
De la Grandière de Noronha Cotta, Maria Ana ULg; Francis, Frédéric ULg; Caij, Ann Brigitte et al

Poster (2012, September)

Objectives African horse sickness is an infectious disease caused by a double stranded positive RNA virus which belongs to the family Reoviridae, genus Orbivirus. The virus has nine known antigenically ... [more ▼]

Objectives African horse sickness is an infectious disease caused by a double stranded positive RNA virus which belongs to the family Reoviridae, genus Orbivirus. The virus has nine known antigenically distinct serotypes and is transmitted by a culicoides biting midge, principally Culicoides imicola. African horse sickness causes severe morbidity and mortality up to 95 % in horses with severe economic losses. The establishment of an experimental mouse model is needed for the investigation of the pathogenesis of this infection. Methods Two mouse models, interferon-α receptor knock-out mice and immunocompetent mice, were tested. The used virus for mice inoculations belonged to the two serotypes which caused epidemics in Europe, serotypes 4 and 9. The virus was inoculated by subcutaneous route and/or by intra-nasal route. Samples of whole blood were taken for each infected and knock-out mice at regular intervals. The organs (liver, spleen, kidney, lung and brain) were taken at the end of experience of when the most affected mices were euthanasied. All these samples were tested by a qRT-PCR targeting African horse sickness genome segment 7. Results The results demonstrate the potential of the immunodeficient mouse model for both clinical and biological features. Both serotypes of African horse sickness were detected by qRT-PCR until three weeks post-infection (corresponding with the end of the experience) in blood. Conclusions The setting up of this mouse model has developed a tool for efficient in vivo study to characterize the in vivo virulence of this virus, to monitor the evolution of viral populations during in vivo replication cycles and to test the competence or vectorial capacity of indigenous Culicoides. Acknowledgement Research supported by the Belgium Federal Public Service, Health, Food Chain Safety and Environment. [less ▲]

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See detailInfluence of sleep homeostasis and circadian rhythm on executive discriminative ability during a constant routine
Jaspar, Mathieu ULg; Meyer, Christelle ULg; Muto, Vincenzo ULg et al

Poster (2012, September)

Introduction & Objectives The human brain upholds cognitive performance throughout a waking day due to putative circadian (C) arousal signal (1) which counteracts the increase in homeostatic (H) sleep ... [more ▼]

Introduction & Objectives The human brain upholds cognitive performance throughout a waking day due to putative circadian (C) arousal signal (1) which counteracts the increase in homeostatic (H) sleep pressure associated to the deterioration in brain efficiency. When wakefulness is extended into the circadian night, maintenance of cognitive performance is jeopardized (Fig.1). Some individuals are very vulnerable to the negative effects of sleep loss and circadian misalignment, whereas others are resilient (3). These individuals differences can be readily explained within the conceptual framework of the circadian and homeostatic regulation of performance (4,5) but also by individual genetic differences and notably the PERIOD3 gene polymorphism (6). In this experiment, we investigated the consequences of sleep deprivation on cognitive performance during a working memory task (3-back). Following the signal detection theory, the ability to discriminate target from non-target stimuli is estimated by d prime (d') and criterion (cr). Here we assessed whether d' and cr were modulated by the raising sleep need and the oscillatory circadian signal. We also tested whether the individual vulnerability to sleep loss predicted by the PERIOD3 gene polymorphism influences this cognitive modulation, which is also driven by the sleep/wake regulation. Materials and Methods Population: Thirty-five right-handed healthy young volunteers aged from 19 to 26 (17 females) were recruited on the basis of their PER3 polymorphism. From a sample of about 400 screened volunteers, twelve 5/5 and twenty-three 4/4 homozygotes (matched for age, gender, chronotype, IQ, and level of education at the group level) participated in this study. Study protocol: Participants wore actigraphs for three weeks before the laboratory study. The first two weeks allowed us to determine their habitual sleep/wake schedule. During the third one, a strict sleep schedule adjusted on two possible timetables (00:00-08:00 or 01:00-09:00) was imposed in order to stagger fMRI sessions. Compliance to this schedule was again checked by wrist actigraphy and sleep diaries. The laboratory study began in the evening of day 1 and ran over 5 nights (Fig. 2). During the first 2 nights (habituation and baseline), the volunteers slept according to habitual sleep/wake schedule. Participants remained awake from the morning of day 3 for 42 hours. During this period, they remained in a semi-recumbent position, under dim light conditions (5 lux, eye level), with no information on clock time, in a constant routine protocol (CR). Saliva samples was hourly collected for melatonin analysis. Every 2 hours, volunteers received calibrated isocaloric snacks, behavioral data were collected and waking EEG recorded. During CR, behavioral measures were used to assess subjective (Karolinska Sleepiness Scale, KSS) and objective alertness (psychomotor vigilance task [PVT]). Executive functioning efficiency was assessed using the 3-back (Fig. 3) and SART tasks. During fMRI, participants performed alternating blocks of 0- and 3-back task. D’ and cr (Fig. 4) were analyzed with mixed-model analysis of variance (PROC Mixed), with main factors “session” and “genotype” (PER3 4/4 & PER3 5/5). All p-values derived from r-ANOVAs were based on Huynh-Feldt's (H-F) corrected degrees of freedom (p<0.05). Exploratory analysis assessed theoretical coefficients for the homeostatic sleep pressure (derived from a quasi-linear function) and the circadian oscillation (as a 24-hour period sine wave) were utilized in a multiple regression model to predict d’ and cr performance during the CR. Before these analyses, d’ and cr have been normalized using a z-score transformation. Results. Analyses on d’ 1. MIXED MODEL : Significant effect of sessions (F(12,385) = 17.16, p < 0.0001), but no group effect (F(1,133) = 0.00, p = 0.99) or interaction (F(12,385) = 1.51, p = 0.11). 2. REGRESSION: Significant regression (R² = 0.24, F(2,440) = 69.94, p <0.0001). The two predictors are significant (homeostat: p < 0.0001 ; circadian: p < 0.0001). Analyses on cr 1. MIXED MODEL : Significant effect of sessions (F(12,385) = 4.12, p < 0.0001), but no group effect (F(1,133) = 0.00, p = 0.99) or interaction (F(12,385) = 0.75, p = 0.71). 2. REGRESSION: Significant regression (R² = 0.04, F(2,440) = 9.35 , p = 0.0001). Only one predictor was significant (homeostat: p < 0.0001 ; circadian: p = 0.96). Conclusion These preliminary results show that both sleep homeostatic pressure and circadian factors influence executive discriminative ability during sleep loss, as assessed by signal detection theory (d’). Decision criterion (cr) appears modulated only by homeostatic sleep pressure. The difference between these two parameters could be explained by the theoretical modeling of the circadian oscillation and future analyses will incorporate individual experimentally-derived homeostatic and circadian parameters. Neither discrimination ability (d’) or criterion (cr) seem sensitive measures of individual cognitive vulnerability to sleep loss predicted by PER3 polymorphism. REFERENCES (1) Aston-Jones. Sleep Med. 2005, 6(Suppl 1), S3-7. (2) Dijk & Archer. Sleep Med. Rev. 2010, 14, 151-160.(3) Van Dongen & al. Sleep. 2004, 27, 423-433. (4) Mongrain & al. J. Sleep Res. 2006, 15, 162-166. (5) Van Dongen et al. Sleep. 2007, 30, 1129-1143. (6) Groeger & al. Sleep. 2008, 31, 1159-1167. (7) Vandewalle & al. J. Neuro. 2009, 29, 7948-7956. ACKNOWLEDGEMENTS & SPONSORS Cyclotron Research Centre (CRC) ; Belgian National Funds of Scientific Research (FNRS) ; Actions de Recherches Concertées (ARC, ULg) – Fondation Médicale Reine Elisabeth (FMRE) ; Walloon Excellence in Lifesciences and Biotechnology (WELBIO) ; Wellcome Trust ; Biotechnology and Biological Sciences Research Council (BBSRC) [less ▲]

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See detailThe Uranus System Explorer (USE) – Unveiling the evolution and formation of icy giants
Costa, Marc; Nordheim, Tom; Provinciali, Lorenzo et al

Poster (2012, September)

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See detailUNFOLDING SYNTHETIC PEPTIDES BY AFM AT THE SINGLE-MOLECULE LEVEL
Willet, Nicolas ULg; Hinterdorfer, Peter; Lecommandoux, Sébastien et al

Poster (2012, September)

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in ... [more ▼]

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in detail by atomic force microscopy (AFM) at the single-molecule level. Synthetic copolymers containing a polypeptide block were prepared by N-carboxyanhydride amino acid ring-opening polymerization. The polymer chains were grafted as a dilute brush onto gold surfaces and their mechanochemical behavior was then studied by AFM single-molecule force spectroscopy (SMFS). The investigated polypeptide blocks were based on poly(L-glutamic acid), which undergoes a transition from alpha-helix to random coil. This can be induced by external stimuli (pH, ionic strength, temperature) or simply by applying a force. We were able to study the mechanically driven unfolding of the peptide by stretching-release cycles of the biomacromolecule. Stretching the helical peptide resulted in original features in the force-distance traces. Plateaus that are specific for the helical conformation were detected, quantified and discussed. Pulling-relaxing SMFS experiments will eventually lead to a better understanding of the force-induced unfolding of an alpha-helix and the reversibility of the phenomenon. [less ▲]

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See detailThe 'Art of the States' Research Project: Performance Effects of Administrative Innovations in US State Governments
Markus, M. Lynne; Bui, Quang Neo; Jacobson, Dax D. et al

Poster (2012, September)

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See detailExperimental Characterisation of Damage Occuring during Single Point Incremental Forming of a Ferritic Steel
Mertens, Anne ULg; Guzmán Inostroza, Carlos Felipe ULg; Habraken, Anne ULg et al

Poster (2012, September)

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid ... [more ▼]

Single Point Incremental Forming (SPIF) has been developed as a new dieless process for forming metal sheets. This technique appears very promising in view of the current requirements for rapid prototyping and/or small series production [1]. However, inaccuracies in the shape of the processed part and material failure constitute important limiting factors for applications. In the present research, a numerical approach, based on the damage model proposed by Gurson [2], has been chosen to analyse and optimise the process, predict the material rupture and the process limit. From experimental observations of plastic deformation and ductile fracture, damage is related to the nucleation, growth and coalescence of microvoids [3]. Gurson’s model uses the volume fraction of these voids as a main variable. Hence the determination of this value is a key factor for a correct identification and validation of the model. More particularly, the present work focuses on two different methods used to experimentally characterise damage occurring during single point incremental forming of a ferritic steel. Void measurements carried out by optical microscopy combined with image analysis have been compared with porosity values obtained from density measurements based on the Archimedes’ principle [4], so as to assess the feasibility of using this method for a quick characterisation of the damage. [less ▲]

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See detailMathematical Level-Set Modelling of Cell Growth on 3D Surfaces
Guyot, Yann ULg; Papatoniou, Ioannis; Chai, Yoke Chin et al

Poster (2012, September)

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See detailChange in naming abilities between the ages of 50 and 90: The importance of analyzing naming latency
Verhaegen, Clémence ULg; Poncelet, Martine ULg

Poster (2012, September)

Introduction This study tests the controversial hypothesis that word naming difficulties may arise in individuals as young as their 50s. According to Feyereisen (1997), these difficulties begin at the age ... [more ▼]

Introduction This study tests the controversial hypothesis that word naming difficulties may arise in individuals as young as their 50s. According to Feyereisen (1997), these difficulties begin at the age of 70, but Nicholas, Connor, Obler, and Albert (1998); Connor, Spiro, Obler, and Albert (2004) observed subtle signs of decreased naming performance in participants in their 50s. However, these studies focused on naming accuracy. To our knowledge, no study has analyzed naming latencies in participants in their 50s in comparison with younger participants. We assume that such analyses may highlight more subtle difficulties in naming. In our study, both naming latencies and naming accuracy were analyzed in a picture naming task presented to 4 age groups: 25-35, 50-59, 60-69 and above 70 years old. If people in their 50s experience subtle naming difficulties, these should be reflected in longer picture naming latencies compared to younger participants. In participants above 70 years of age, the decline should be more apparent and may be underlined not only by slower naming latencies but also by lower picture naming scores. The explanation for naming difficulties in aging is also a matter of debate. According to some authors (e.g., Salthouse, 1996), these difficulties are a consequence of a general slowing in all cognitive tasks, including language, in the elderly. However, other theories suggest that the relevant difficulties are more language-specific and are due to connection weaknesses across the entire language system, leading to more naming errors and longer naming latencies (e.g., Burke, MacKay, Worthley, & Wade, 1991). In order to determine the extent to which the slowing of naming latencies in the elderly is related to a slowing of cognitive processing, participants’ cognitive processing speed was assessed with an odd/even judgment task. We were also interested in seeing whether slowing on the odd/even judgment task arises at the same age than slowing on the picture naming task. Methods Participants Four groups of 30 participants took part in the present study: (1) between 25 and 35 years of age, (2) between 50 and 59 years of age, (3) between 60 and 69 years of age and (4) above 70 years of age (70+). All subjects were native French speakers and reported no history of neurological, cardiac, neuropsychological or psychiatric disorders, and no uncorrected hearing or visual problems. Dementia was excluded with the Mattis Dementia Rating Scale (Schmidt, Freidl, Fasekas, Reinhart, & Grieshofer, 1994). No differences between groups were found for vocabulary level (Mill Hill test; Deltour, 1993) or socio-economic background. Materials Participants performed a picture naming task (150 black and white drawings selected from the set of Bonin, Peereman, Maladier, Méot, and Chalard, 2003). Both the number of correct responses and naming latencies were analyzed. We also analyzed response latencies on an odd/even judgment task on 50 digits from 1 to 9, to assess cognitive processing speed. Results For the picture naming task, an analysis of variance (ANOVA) performed on the number of correctly named items revealed an effect of age, F(3,116)=35.36, p<.001. Tukey post hoc comparisons (p<.05) indicated that the 70+ age group named fewer items correctly than the 60-69 age group, which performed worse than the 25-35 and 50-59 age groups, which in turn did not differ from each other. However, the ANOVA performed on correct naming latencies did not show the same pattern of results. This analysis revealed an effect of age, F(3,116)=35.36, p<.001. Tukey post hoc comparisons (p<.05) indicated that the 25-35 age group responded faster than the 50-59 and 60-69 age groups, which did not differ from each other. The 70+ age group responded more slowly than the 3 younger groups. For the odd/even judgment task, the ANOVA performed on response latencies indicated an effect of age, F(3,116)= 96.40, p<.001. Tukey post hoc comparisons (p<.05) showed that the 25-35 and 50-59 age groups did not differ from each other and responded faster than the 60-69 and 70+ age groups, which in turn did not differ from each other. An analysis of covariance was also performed on naming latencies, using the latencies on the odd/even judgment task as covariate. There was a significant effect of age, F(4,115)=54.56, p<.001. Tukey post hoc analysis indicated that the 25-35 age group responded faster than the 50-59 and 60-69 age groups, which did not differ from each other. The 70+ age group performed more slowly than the 3 younger groups. Thus, a slowing of picture naming latencies was found in participants above 50 years of age. This slowing remained significant even when cognitive processing speed was controlled for. Discussion The increase in correct naming latencies on the picture naming task in participants in their 50s suggests the presence of subtle age-related word finding difficulties. In participants in their 60s, naming difficulties were highlighted by both a decrease in correct responses and an increase in naming latencies. Finally, in participants above 70 years of age, these difficulties became more pronounced in both naming accuracy and naming latencies. Slowing on the picture naming task appears to be greater and to arise earlier in the adult lifespan (in participants in their 50s) than slowing on the odd-even judgment task assessing processing speed (in participants in their 60s). Moreover, this slowing of picture naming latencies in participants in their 50s remained significant even when processing speed was controlled for with an analysis of covariance. In conclusion, these results support the importance of naming latency analyses in uncovering subtle naming difficulties. Furthermore, although we do not exclude a possible impact of general slowing on naming latencies in participants above 50 years of age, these findings suggest that the slowing in naming at this age observed here may be explained by a specific age-related slowing within the language system. References Bonin, P., Peereman, R., Maladier, N., Méot, A., & Chalard, M. (2003). A new set of 299 pictures for psycholinguistic studies: French norms for name agreement, image agreement, conceptual familiarity, visual complexity, image variability, age of acquisition, and naming latencies. Behavior Research Methods, Instruments, & Computers, 35(1), 158-167. Burke, D. M., MacKay, D. G., Worthley, J. S., & Wade, E. (1991). On the tip of the tongue: what causes word finding failures in young and older adults? Journal of Memory and Language, 30(1), 542-579. Connor, L.T., Spiro, A., Obler, L. K., & Albert, M. L. (2004). Change in object naming ability during adulthood. The Journals of Gerontology: Series B, 59(5), 203-209. Deltour, J. J. (1993). Echelle de vocabulaire Mill Hill de J.C. Raven. Braine-le-Chateau, Belgium: Editions l’Application des Techniques Modernes. Feyereisen, P. (1997). A meta-analytic procedure shows an age-related decline in picture naming: Comments on Goulet, Ska et Kahn (1994). Journal of Speech, Language, and Hearing Research, 40(1), 1328-1333. Nicholas, M., Connor, L.T., Obler, L. K., & Albert, M. L. (1998). Aging, Language, and Language Disorders. In M. Taylor Sarno (Ed.), Acquired Aphasia (pp. 413-449). San Diego, CA: Academic Press. Salthouse, T. A. (1996). The processing-speed theory of adult age differences in cognition. Psychological Review, 103(3), 403-428. Schmidt, R., Freidl, W., Fasekas, F., Reinhart, B., & Grieshofer, P. (1994). Mattis Dementia Rating Scale. [less ▲]

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See detailMolecular epidemiology of norovirus in symptomatic and asymptomatic population in Burkina Faso
HUYNEN, Pascale ULg; Mauroy, Axel ULg; Martin, Caroline et al

Poster (2012, September)

Background Noroviruses (NoV), belonging to the family Caliciviridae, are now recognized as the leading cause of gastroenteritis outbreaks worldwide, and represent an important cause of sporadic ... [more ▼]

Background Noroviruses (NoV), belonging to the family Caliciviridae, are now recognized as the leading cause of gastroenteritis outbreaks worldwide, and represent an important cause of sporadic gastroenteritis in both children and adults. Many studies describe NoV epidemiology. However, few data are available about the NoV strains circulating in most of African countries, in particular in Burkina Faso. The population of Burkina Faso is characterized by the young age of its habitants, and most are living in rural environment. Objectives The purpose of this epidemiological study was to determine the prevalence of NoV in Bobo Dioulasso (Southern part of Burkina Faso) by molecular diagnosis methods in patients presenting or not gastroenteritis symptoms, to quantify the excreted viral load, and to genotype the circulating strains. Methods Patients with and without gastro-intestinal disorders were selected in several Health Care Centres of Bobo Dioulasso. Clinical and epidemiological data, as well as stool samples, were collected during 8 weeks through March to April 2011. Viral genomic RNA was automatically extracted with a Maxwell® (Promega) instrument. Molecular detection of genogroups (G) I, II and IV NoV in stool samples was performed by a home-made real-time RT-PCR targeting the ORF1-ORF2 polymerase junction region. For each positive sample, viral load was estimated by using standard curves (successive dilutions of recombinant GI and GII plasmids). Molecular characterization was performed on the detected strains, using both polymerase and capsid regions. Results NoV were detected in 21.6% of the 453 collected stool samples, with a distribution of 21.0% and 23.1% in the samples from the 319 symptomatic (SP) and the 134 asymptomatic patients (AP) respectively. Genogroup distribution was 7.2% for GI, 10.7% for GII and 3.1% for both GI and GII among SP’s samples, and was 11.2% for GI, 10.4% for GII and 1.5% for both GI and GII among AP’s samples. Average viral load values were higher for GI NoV in SP than in AP (p=0.02), when they were higher for GII NoV in AP than in SP (p=0.04). Phylogenic analysis showed a high degree of genotypical diversity in both groups of patients. One recombinant strain GII.7/GII.6 was also detected, to our knowledge, for the first time. Conclusion Even if a true pathogenic role of NoV could not be showed from the study design, it allowed to precise the molecular epidemiology of NoV strains prevalent in a representative country of the East African region. It also showed that asymptomatic patients could play an important role as a NoV “reservoir”. Despite the fact that GII strains, and more precisely those belonging to GII.4 genotype, are nowadays highly reported worldwide, the surprising proportion of NoV GI detected in this study suggests that GI and GII strains should be excreted in equal proportion in the environment. The origin of this epidemiologic difference, even if partially explained by the difference in immunity and genetic sensitivity of the population, is still to be solved. [less ▲]

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See detailValidation par biomarqueurs d’un FFQ permettant d’étudier le lien entre alimentation et risques cardiovasculaires
Sauvageot, Nicolas ULg; Alkerwi, Alaa; Donneau, Anne-Françoise ULg et al

Poster (2012, September)

Introduction La recherche sur l'alimentation et son lien avec les maladies nécessite une collecte rigoureuse des données nutritionnelles permettant d'estimer avec précision l'apport nutritionnel. Le « ... [more ▼]

Introduction La recherche sur l'alimentation et son lien avec les maladies nécessite une collecte rigoureuse des données nutritionnelles permettant d'estimer avec précision l'apport nutritionnel. Le « Food Frequency Questionnaire (FFQ) » a été choisie pour étudier le lien entre alimentation et risques cardiovasculaires dans un échantillon représentatif de la Grande région recruté pour l’étude NESCAV (Nutrition, environnement et santé cardio-vasculaire). Objectif Valider le FFQ utilisé à l’aide de biomarqueurs afin d’évaluer son habilité à estimer correctement les habitudes alimentaires. Méthodes Afin de prendre en compte les spécificités de la Grande région et le volet cardio-vasculaire, la liste d’items d’un FFQ existant a été modifiée et élargie. Tous les nutriments calculés à partir du FFQ ont été ajustés par rapport à l’énergie par la méthode des résidus. La comparaison des nutriments calculés par le FFQ et les bio-marqueurs correspondants a été faite par le calcul des coefficients de corrélation avec ajustement sur plusieurs facteurs confondants. L’accord entre les deux méthodes a été estimé par le calcul des pourcentages de concordance et du coefficient Kappa. Résultats La validation s’est effectuée sur un échantillon de 466 sujets (236 hommes et 241 femmes). Des corrélations significatives ont été observées pour les folates, le β-carotène dans les deux sexes et pour la vitamine B12 et l’iode chez les femmes. Discussion Ces résultats sont comparables à ceux d’études précédentes. Les corrélations sont souvent expliquées par le fait que les nutriments du FFQ représentent la quantité ingérée alors que les biomarqueurs représentent la quantité absorbée par le corps. [less ▲]

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See detailInfluence of sleep homeostasis and circadian rhythm on waking EEG oscillations during a constant routine
Muto, Vincenzo ULg; Meyer, Christelle ULg; Jaspar, Mathieu ULg et al

Poster (2012, September)

Introduction & Objectives Human sleep and wake EEG oscillations are modulated by complex non-additive interaction between homeostatic and circadian processes. Quantitative analysis of EEG data, during ... [more ▼]

Introduction & Objectives Human sleep and wake EEG oscillations are modulated by complex non-additive interaction between homeostatic and circadian processes. Quantitative analysis of EEG data, during extended wakefulness, indicate that its frequency-specificity is influenced by both factors, such that low-frequencies (<8Hz) increase with time spent awake (1), thus more homeostatically-driven, while alpha activity undergoes a clear circadian modulation (2). Interindividual differences in sleep-wake regulation in young volunteers are associated with the variable-number tandem-repeat (VNTR) polymorphism in the coding region of the circadian clock gene PERIOD3 (PER3). Individuals homozygous for the longer allele of PER3 (PER35/5) were reported to generate more slow wave activity during NREM sleep and theta activity during wakefulness, relative to individuals with the shorter allele (PER34/4). However, the phase and amplitude of circadian markers do not differ between these genotypes (3). Here we tested the hypothesis if fluctuations in the dynamics of waking EEG frequency-specificity are modulated by a polymorphism in the clock gene PER3, under 42h of sustained wakefulness. Materials and Methods Population. A total of 400 young men and women were recruited, from whom DNA samples and questionnaire data were collected. On the basis of their PER3 polymorphism, 35 healthy young volunteers (age: 19-26 y; 17 females) were recruited, out of which twelve were PER35/5 and twenty-three PER34/4 homozygotes, and matched by age, gender, level of education, chronotype and IQ at the group level. Study protocol. The laboratory part of this study began in the evening of day 1 until day 5 (Fig. 1). During the first 2 nights (habituation and baseline), volunteers followed one out of two possible sleep-wake schedules (00:00-08:00 or 01:00-09:00). Thereafter, participants underwent approximately 42 hours of sustained wakefulness under constant routine (CR) conditions (semi-recumbent position, dim light <5 lux, no time-of-day information), and a subsequent recovery sleep episode. EEG recordings. Continuous EEG measurements with 9 EEG channels (F3, Fz, F4, C3, Cz, C4, Pz, O1, O2) were performed throughout the CR. Waking EEG was recorded every 2-h, during a modified version of the Karolinska Drowsiness Test (KDT) (4). Data presented here pertain to the last 60-sec of KDT, during which subjects were instructed to relax, to fixate a dot displayed on a screen ca. 75cm and to try to suppress blinks. After re-referencing to mean mastoids, recordings were scored using Rechtschaffen criteria. The 1-min EEGs during the KDT were manually and visually scored for artifacts (eye blinks, body movements, and slow eye movements) offline by 2 independent observers. The absolute EEG power density was then calculated for artifact-free 2-s epochs in the frequency range of 0.5 to 20 Hz , overlapping by 1 second using the pwelch function in MATLAB (7.5.0). For data reduction, power density of artifact-free 2-s epochs was averaged over 20-s epochs. Statistics. Waking EEG delta (0.75-4.5Hz), theta (4.75-7.75Hz) and alpha (8-12.0Hz) power density computed on Central derivation (Cz) were analyzed with a mixed-model analysis of variance (PROC Mixed), with main factors “elapsed time awake” and “genotype” (PER34/4 and PER35/5), and the interaction of these two factors. All p-values derived from r-ANOVAs were based on Huynh-Feldt's (H-F) corrected degrees of freedom (p<0.05). Multiple comparisons were performed using Tukey-Kramer test. Theoretical coefficients for the homeostatic sleep pressure (derived from a quasi-linear function) and the circadian oscillation (24-hour period sine wave) were used in a multiple regression model to predict delta, theta and alpha activity during the CR. Prior to multiple regression analysis, data were normalized according to PROC Transreg, in order to derive the best normalization method for linear and non-linear datasets. Results. Delta activity Analysis of delta activity yielded a significant main effect of “elapsed time awake” (F=5.31; p < 0.0001), albeit no significant effects for “genotype” (F=0.01; p = 0.94) nor for the interaction of these factors (F=0.85; p = 0.65). The multiple regression model revealed a significant regression (R² = 0.0433 Adj. R² = 0.0404; F = 15.24; p <0.0001), for the homeostat (p < 0.0001 ) and circadian (p = 0.0006) coefficients. Theta activity Analysis of theta activity yielded a significant main effect of “elapsed time awake” (F= 12.2; p < 0.0001), although no significant effects for “genotype” (F= 0.1; p = 0.70) nor for the interaction of these factors (F= 0.67; p = 0.86). The multiple regression model revealed a significant regression (R²= 0.072 Adj. R² =0.069; F= 26.36; p <0.0001), for the homeostat (p < 0.0001 ) and circadian (p < 0.0001 ) coefficients. Alpha activity Analysis of alpha activity yielded a significant main effect of “elapsed time awake”(F=3.43; p < 0.0001), although no significant effects for “genotype” (F = 0.01; p = 0.92) nor for the interaction of these factors (F= 1.23; p = 0.22). The multiple regression model revealed a significant regression (R²=0.052; Adj. R²=0.05; F =18.63; p <0.0001), for the homeostat (p = 0.0012) and for the circadian (p < 0.0001) coefficients. Conclusion Our results indicate that fluctuations in the dynamics of waking EEG activity are modulated by the circadian and homeostatic processes, although the magnitude of these differences are not underlined by a polymorphism in the clock gene PER3. REFERENCES 1. Cajochen C, Brunner DP, Kräuchi K, Graw P, Wirz-Justice A. Power density in theta/alpha frequencies of the waking EEG progressively increases during sustained wakefulness. Sleep. 1995, 10:890-894. 2. Cajochen C, Wyatt JK, Czeisler CA, Dijk DJ.Separation of circadian and wake duration-dependent modulation of EEG activation during wakefulnessNeuroscience. 2002, 114:1047-60. 3. Viola AU, Archer SN, James LM, Groeger JA, Lo JC, Skene DJ, von Schantz M, Dijk DJ PER3 polymorphism predicts sleep structure and waking performance. Curr Biol 2007,17:613–618. 4. Gillberg M, Kecklund G, Akerstedt T. Relations between performance and subjective rating of sleepiness during a night awake. Sleep 1994, 17:236-241. ACKNOWLEDGEMENTS & SPONSORS Cyclotron Research Centre (CRC) ; Belgian National Funds of Scientific Research (FNRS) ; Actions de Recherche Concertées (ARC, ULg) – Fondation Médicale Reine Elisabeth (FMRE) ; Walloon Excellence in Lifesciences and Biotechnology (WELBIO) ; Wellcome Trust ; Biotechnology and Biological Sciences Research Council (BBSRC) [less ▲]

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See detailPET In Conscious Rodents - Quantification of Stress During The Training Process
Warnock, Geoffrey ULg; Bahri, Mohamed Ali ULg; Bretin, Florian ULg et al

Poster (2012, September)

Recently several methods for performing PET studies in conscious rodents have been developed [1-3]. These methods have the potential to greatly improve the translational nature of PET studies in rodents ... [more ▼]

Recently several methods for performing PET studies in conscious rodents have been developed [1-3]. These methods have the potential to greatly improve the translational nature of PET studies in rodents. One of the most easily implemented methods is the training of a rat to tolerate head fixation in a restraining device. Training consists of intervals of restraint over several days. However, the stress induced by this training procedure has not been quantified in detail. Limited changes in plasma corticosterone have been reported, but this data may be confounded by sample timing and baseline levels. An implantable telemetry system (Telemetry Research) was used to remotely measure blood pressure, heart rate and core temperature during training. Transmitters were implanted in the abdominal cavity under isoflurane anesthesia, with the blood pressure sensor fixed in the abdominal aorta. Training was started after a recovery period of at least 1 week. Training consisted of a 5 min period of acclimatization in the cage containing the restraining device, followed by increasing durations of restraint in the device on subsequent training days (15, 30, 45, 60, 90 min). Telemetry data was acquired from 5 min prior to acclimatization to 60 minutes post-training. In this initial pilot study, a single rat was trained, without head fixation, for 4 consecutive days and again on day 7. All reported values are mean ± SEM across the five training days. In the home cage, prior to acclimatization, baseline heart rate (HR) was 294 ± 15 bpm. During the acclimatization period, HR was elevated to 411 ± 7 bpm. Immediately after starting training, HR was 419 ± 16 bpm. During the training period HR showed a tendency to decrease, with raised periods at undefined intervals. After return to the home cage, HR remained elevated for 15-20 min before returning to a value (313 ± 9 bpm) close to baseline. A similar pattern was seen in blood pressure (mean; BP). Baseline BP was 76 ± 7 mmHg, increasing to 94 ± 9 mmHg during acclimatization. After commencing training, a peak in BP was reached at 102 ± 8 mmHg. After the 15-20 min recovery interval, BP returned to a baseline of 77 ± 9 mmHg. The HR and BP responses to acclimatization and to the training protocol persisted throughout all training days, with the main noticeable difference being the number of bouts of increased HR, which increased with training duration. Core body temperature (baseline: 37.45 ± 0.21 °C) increased during restraint training, with a subsequent post-training peak (38.21 ± 0.03 °C). Measurement of core temp is complicated during longer training sessions by the need to charge the transmitter. This early data indicates that stress induced by the training procedure for conscious PET persists after several days of training. In subsequent studies the head will be fixed and the effect of the training on plasma corticosterone and central glucose metabolism (using [18F]FDG) will be examined. [1] Momosaki et al. (2004) Synapse 54:207–213 [2] Wyss et al. (2009) NeuroImage 48:339–347 [3] Itoh et al. (2009) J Nucl Med 50:749–756 [less ▲]

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See detailA confocal microscopic study of mitochondrial alterations of renal HK-2 cells exposed to an endotoxic stress
Quoilin, Caroline ULg; Mouithys-Mickalad, Ange ULg; Fontaine-Aupart, Marie-Pierre et al

Poster (2012, September)

Sepsis has a profound deleterious effect on kidney functions through complex mechanisms, which involve the immune response, inflammatory pathways, intracellular dysfunction and hemodynamic instability ... [more ▼]

Sepsis has a profound deleterious effect on kidney functions through complex mechanisms, which involve the immune response, inflammatory pathways, intracellular dysfunction and hemodynamic instability. Those factors are difficult to discriminate in vivo. To get a better understanding of renal respiratory dysfunction, we developed an in vitro model of sepsis-induced acute kidney injury using proximal tubular epithelial cell lines (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Using this model, our first work has demonstrated that the basal respiration of renal HK-2 cells subjected to endotoxins was altered and presented a strong decrease in the oxygen consumption rates. Our working hypothesis of the pathophysiology of sepsis-induced AKI is based on a change in mitochondrial function that has been termed cytopathic hypoxia. A consequence of mitochondrial function alterations is an inability of the cell to use molecular oxygen for ATP production. The oxidative phosphorylation within mitochondria is interrupted because of the inhibition of cytochrome oxidase. The present investigation was carried out to establish whether mitochondrial alterations might be a mechanism of renal tubular epithelial injury during sepsis. To reach this goal the mitochondrial alterations of renal HK-2 cells exposed to an endotoxic stress was studied by confocal laser-scanning microscope. Confocal microscope allowed observation of the evoked phenomena at the single cell level and in real time. More particulary, mitochondrial morphology, mitochondrial membrane potential (ΔΨm) and generation of reactive oxygen species were recorded using specific vital fluorescent probes and quantified by image processing and analysis. Mitochondrial membrane potential is generated by the mitochondrial electron transport chain. This gradient is critical for the formation of ATP, and a fall in membrane potential is an indicator of mitochondrial dysfunction. ΔΨm was measured using the lipophilic cationic probe TMRE and it was shown that LPS produced a decrease in ΔΨm. In parallel, superoxide generation was measured by using MitoSOX which is selectively targeted to the mitochondria. There was a significant increase in mitochondrial superoxide-specific oxidation of MitoSOX when HK-2 cells were submitted to LPS. Overall, the model of HK-2 cells exposed to LPS displays some key features of sepsis-induced acute kidney injury. The confocal microscopy study has suggested a mechanism of toxicity dependent on mitochondrial oxidant generation and mitochondrial dysfunction. Indeed, the exposure to LPS has resulted in an increased generation of superoxide and a loss of mitochondrial function probably initiated by a fall in mitochondrial potential. [less ▲]

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See detailEsthétique des os : la dimension réflexive des radiographies érotiques
Sturnack, Lionel ULg

Poster (2012, September)

L’analyse portera sur une œuvre de l’artiste italienne Benedetta Bonichi, titrée Striptease. Il s’agit d’une réalisation à mi-chemin entre les procédés de la photographie et ceux du rayon-x, présentant un ... [more ▼]

L’analyse portera sur une œuvre de l’artiste italienne Benedetta Bonichi, titrée Striptease. Il s’agit d’une réalisation à mi-chemin entre les procédés de la photographie et ceux du rayon-x, présentant un modèle féminin dans une pose érotique. L’objectif de la présentation sera d’exposer le discours réflexif qui se développe dans Striptease, grâce à la décomposition de sa complexité énonciative et figurative. L’œuvre sera envisagée à l’intérieur d’un ensemble de productions artistiques issues des procédés de la radiographie. En première instance, nous procéderons à une description de l’œuvre sous l’aspect des formants plastiques qui la composent et de leur organisation particulière. Cette première partie, brève, sera menée en accord avec les propositions de Jean-Marie Floch dans Petites mythologies de l’œil et de l’esprit et dans Formes de l’empreinte. Elle permettra d’obtenir une base descriptive stable au sein de laquelle d’autres radiographies artistiques pourront être envisagées. Ainsi, six œuvres d’artistes de différents horizons, dont celle de Benedetta Bonichi, seront abordées afin d’exposer différents types de variations repérables sur la base de la description plastique effectuée précédemment. Sous ces préalables, il sera possible de catégoriser quelques variations remarquables dans un ensemble d’œuvres homogène du point de vue de ses procédés énonciatifs. Enfin seront approfondies plus longuement les relations notables entre trois niveaux thématiques, tels qu’ils ont été définis par François Rastier dans Systématique des isotopies, où l’auteur propose une lecture sémantique faisant se croiser trois thèmes (pratique, mythique et métalinguistique) qui structurent un texte. Ces relations, également observables dans les travaux mis en analyse, permettront de systématiser leur approche, en soulignant les tensions particulières qui s’y tissent. Aussi, dans cette dernière approche, l’étude se focalisera sur trois œuvres partageant à la fois les mêmes procédés énonciatifs issus de la radiographie, et à la fois le même thème figuratif ou mythique. En l’occurrence, l’érotisme sera interrogé dans son dialogue avec les procédés du rayon-x dans trois compositions, de Benedetta Bonichi, de Wim Delvoye et de l’agence publicitaire Butter. Différents aspects de ce dialogue thématique seront développés, avec un accent particulier sur la complexité du travail de la photographe italienne, dont la portée réflexive questionne le domaine du visuel, notamment sous l’aspect de l’outillage scientifique qui s’y inscrit. [less ▲]

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See detailAcute burn care : state of the art in Europe
ROUSSEAU, Anne-Françoise ULg; LEDOUX, Didier ULg; MASSION, Paul ULg et al

Poster (2012, September)

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See detailLa perception de la pénibilité au travail dans les métiers du social
Dubois, Valérie ULg; Cornet, Annie ULg

Poster (2012, September)

Cet article vise à mettre en évidence les sources de pénibilité au travail telles qu’elles sont perçues par les membres d’une organisation du secteur non-marchand qui travaillent avec des femmes victimes ... [more ▼]

Cet article vise à mettre en évidence les sources de pénibilité au travail telles qu’elles sont perçues par les membres d’une organisation du secteur non-marchand qui travaillent avec des femmes victimes de violence conjugale. Il s’agit de comprendre leurs représentations de la pénibilité du travail, ses effets sur leur santé et bien-être et les politiques de GRH qui pourraient être mises en place pour réduire cette pénibilité. L’originalité de notre communication réside dans le secteur étudié. La thématique de la pénibilité a surtout été étudiée dans des secteurs majoritairement masculins comme la construction et l’industrie. S’il existe quelques travaux sur le secteur de la santé, il existe peu de travaux sur la pénibilité des emplois, majoritairement féminins, du secteur associatif. Cette communication est basée sur des interviews qualitatives réalisées avec les différentes catégories du personnel. Elle répondait à une demande du conseil d’administration qui envisageait de mettre en place une politique de réduction du temps de travail en lien avec l’ancienneté et l’âge sur base de la pénibilité des tâches et qui voulait tester la pertinence d’une telle décision auprès du personnel. L’étude montre que la pénibilité ressentie n’est pas seulement liée à l’âge et à l’ancienneté mais également à des contraintes individuelles (comme la situation familiale) et organisationnelles, notamment les contraintes psychologiques liées au travail avec des personnes ayant vécu un traumatisme. L’étude montre l’importance des politiques de GRH et des styles de management. Donner de l’autonomie au travailleur et des opportunités de développer de nouveaux projets est perçu par tous comme un facteur permettant de réduire la pénibilité. Tous réclament, par contre, une meilleure communication et information sur les tâches et rôles de chacun et plus de synergie entre les équipes. [less ▲]

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See detailMolecular detection of HAV by a new one step real time RT-PCR
Zonta, William ULg; Denayer, Sarah; Thiry, Etienne ULg et al

Poster (2012, September)

Introduction and objectives Hepatitis A virus (HAV) is a RNA virus with a single-stranded positive sense genome and the only species of the genus Hepatovirus of the Picornaviridae family. Belgium and ... [more ▼]

Introduction and objectives Hepatitis A virus (HAV) is a RNA virus with a single-stranded positive sense genome and the only species of the genus Hepatovirus of the Picornaviridae family. Belgium and European countries in general, are countries with a low prevalence and the majority of adults can be infected. HAV is mainly transmitted by the fecal-oral route and even if foodborne outbreaks account for less than 5 % of the reported cases per year, the source of infection cannot be identified in 50 % of the reported cases. Therefore the contribution of foodborne infection is probably underestimated. Viral loads in food samples are lower than in clinical samples and their detection requires refined molecular detection methods. Methods A one step real-time RT-PCR to detect HAV, with new primers (HAV F2 and HAV R2) and probe (HAV P2) was performed directly on HAV diluted suspensions and on food samples (dates) and was compared with a ready-to-use commercial kit. Before the one step real time RT-PCR, a preliminary step combining concentration of viral particles with polyethyleneglycol and centrifugation was used on food samples. Results Real time RT-PCR one step with HAV F2/R2/P2 is more efficient but less sensitive than the commercial kit. It could be used to confirm a positive sample or to detect HAV in an unknown sample. With cell cultured HAV, the limit of detection (LOD) is 1.25 infectious particles in volume tested by RT-PCR or 102 TCID50/ml. In food samples, LOD is between 25 infectious particles and 250 infectious particles in volume tested by RT-PCR or between 104 and 105 TCID50/ml. Several hypotheses could explain these results: the loss of viral particles during the extraction process, the low efficiency of RNA extraction and interference of food on molecular detection. Conclusion Molecular detection of virus in food samples remains a challenge and the protocol of extraction should be improved and adapted at each food category to increase the sensitivity of detection in food matrices characterized by a low viral contamination. [less ▲]

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See detailEvaluation des modèles climatiques régionaux MAR et WRF sur le Svalbard
Lang, Charlotte ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2012, September)

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence ... [more ▼]

: Il est bien connu que les zones de hautes latitudes sont très sensibles aux changements climatiques. A cause du réchauffement global, la fonte des calottes a augmenté, ce qui à son tour a une influence sur le climat via des modifications de la circulation thermohaline, la rétroaction de l’albédo de la glace, l’augmentation du niveau des mers… Nous avons comparé le climat du Svalbard modélisé par deux modèles régionaux (MAR et WRF) à une résolution de 10 km sur la période 2000-2010 à des mesures provenant de plusieurs stations météorologiques localisées dans différentes régions de l’archipel afin d'évaluer lequel de ces modèles pouvait représenter au mieux le climat du Svalbard. [less ▲]

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See detailThe detection and characterization of broad-leaved forest canopy gaps: a regeneration perspective
Bonnet, Stéphanie ULg; Bauwens, Sébastien; Lehaire, François ULg et al

Poster (2012, September)

Canopy gaps are areas of high regeneration potential and, in uneven-aged forest, gaps are therefore places of particular care for the forest manager. Nevertheless the cartography and characterization of ... [more ▼]

Canopy gaps are areas of high regeneration potential and, in uneven-aged forest, gaps are therefore places of particular care for the forest manager. Nevertheless the cartography and characterization of canopy gaps are complex issues. This paper addresses the fundamental question of the canopy gap definition: what is the minimal area, the maximal height of vegetation, type of regeneration, etc? From a regeneration point of view, canopy gaps can be defined as holes in the forest cover where light conditions are suitable for recruitment. As an active sensor, LiDAR has made it possible to tackle the problems of shadows and penetration into the canopy, typical of aerial images. This study investigates the cartography and characterization of forest canopy gaps as areas of natural regeneration. [less ▲]

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See detailCHARACTERIZATION OF A NOVEL RADIOTRACER TARGETING SYNAPTIC VESICLE PROTEIN 2A (SV2A)
Warnock, Geoffrey ULg; Aerts, Joël ULg; Bahri, Mohamed Ali ULg et al

Poster (2012, September)

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been ... [more ▼]

Synaptic vesicle protein 2A (SV2A) has been identified as the binding site of the antiepileptic levetiracetam (Keppra) [1]. SV2 proteins are critical for proper nervous system function and have been demonstrated to be involved in vesicle trafficking. Their implication in epilepsy makes them an interesting therapeutic target, and the widespread distribution of SV2A in particular may provide an opportunity to develop a PET-based measure of neuronal function in brain diseases. [18F]UCB-H is a fluorine-18 radiolabelled PET imaging agent with a nanomolar affinity for the human SV2A protein. Preclinical PET studies in rodents were carried out using male SD rats, imaged under isoflurane anaesthesia in a Siemens Concorde Focus 120 microPET scanner. Arterial input function was measured using an arteriovenous shunt method and beta microprobe system. [18F]UCB-H was injected IV (3.8 ± 0.54 mCi bolus, specific activity 8.5 ± 0.86 Ci/Emol immediately after synthesis) and dynamic PET data acquired in list mode for 90 min. Images were reconstructed using filtered back projection with correction for all physical effects except scatter. These scans revealed high uptake of [18F]UCB-H in brain and spinal cord, matching the expected homogeneous distribution of SV2A in the rodent brain [2]. Notably, the kinetics of [18F]UCB-H uptake in the brain were fast, peaking at up to 30 % ID/cm3 before a rapid decline. Metabolism of [18F]UCB-H in vivo followed a typical pattern of rapid initial metabolism followed by a reducing rate of metabolism over time, with less than 20% of the activity in plasma attributable to the parent compound after 30 minutes, and was highly reproducible between subjects. One major metabolite was identified. The uptake of [18F]UCB-H in the brain over time was well fitted by a classical 1-tissue compartment model. Mean parameter estimates (mean ± SD, n=7, whole brain VOI) were K1: 3.58 ± 0.65 ml/cm3/min, k2: 0.21 ± 0.03 min-1, Vt: 17.21 ± 2.52 ml/cm3. Uptake of [18F]UCB-H was blocked by pretreatment with brivaracetam (21 mg/kg IV, 10 min prior to [18F]UCB-H), a recently described high affinity SV2A ligand with a 20-fold higher affinity for SV2A than levetiracetam [3]. In contrast, pretreatment with ucb-100230-1, a diastereoisomer of brivaracetam with 3200-fold lower affinity for SV2A [3], had no clear effect of the brain uptake of [18F]UCB-H. Our results indicate that [18F]UCB-H is a suitable radiotracer for the quantification of SV2A proteins in vivo and for estimating target occupancy of drugs targeting SV2A. This is the first PET tracer for in vivo quantification of SV2A. The necessary steps for implementation of [18F]UCB-H production under GMP conditions have been completed and first in human studies are planned. References [1] Lynch, B.A. et al. (2004) PNAS 101(26):9861-6. [2] Janz, R. & Sudhof, T.C. (1999) Neuroscience 94(4):1279-1290.[3] Gillard, M. et al. (2011) Eur J Pharmacol 664:36-44. [less ▲]

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See detailPhenotypical and Genotypical Surveillance of Macrolide and Lincosamide Resistance in Group B Streptococcus in Belgium
DESCY, Julie ULg; Ackermans, Yannick; BOREUX, Raphaël ULg et al

Poster (2012, September)

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased ... [more ▼]

Background: Constant increase of erythromycin (E) and clindamycin (C) resistance (R) has been observed worldwide among isolates of group B streptococci (GBS). In Belgium, through the 2000s, E R increased rapidly from 10% to up to 30%. Therefore phenotypical and molecular surveillance of E and C R has to be conducted. Methods: 275 clinical isolates (N1) were obtained from a Belgian surveillance for invasive GBS disease in newborns (59 isolates with 32 early- and 27 late-onset diseases) and adults (216 strains) during 2008 to 2011 and 53 isolates (N2) from vagino-rectal colonization in pregnant women in 2010. E and C MICs were determined by using Etest® (EUCAST interpretive criteria). Furthermore, for the E R isolates, the inducible (iMLS), constitutive (cMLS) and M phenotypes were assessed by a double disk diffusion test; the distribution of genes encoding RNA methylases and efflux pumps was investigated by PCR. Results: Of the N1 and N2 isolates, 92 (33.5%) and 15 (28.3%) were respectively R to E, with a higher rate among serotype V (p <0.001) and serotype IV (p <0.05). Among these 107 E-R isolates, 100 (93.5%) exhibited the MLS phenotype (R to E and CC): 73 were cMLS with E MIC50 >256 mg/L and 27 iMLS with E MIC50/MIC90 12/>256 mg/L. The M phenotype (R to E and S to C) was expressed by 7 (6.5%) of E R isolates with E MIC50/MIC90 4/12 mg/L. One colonizing strain presented a newly described resistance mechanism in GBS: the L phenotype (S to E and R to C) with a C MIC at 8 mg/L. For cMLS, the most common E R genotype was ermB (66%) (p <0.05) followed by ermTR (29%) and ermB+ermTR (5%). All iMLS isolates harbored an ermTR gene except 3 (2 with ermB, 1 with both ermB and ermTR); and all M phenotype were positive for mefA/B gene. Conclusions:1) In Belgium, by year 2010, prevalence of macrolides R in GBS exceeded 30%, 2) MLS R phenotypes (target-site modification) were the majority mechanism; M phenotype (efflux R mechanism) was also prevalent. 3) E and C susceptibility testing and surveillance are mandatory to guide prophylaxis and treatment of serious GBS infections in penicillin-allergic patients (at high risk for anaphylaxis) but also to identify emergence of newly acquired resistance mechanisms such as the L phenotype. [less ▲]

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See detailCharacterisation of a scroll expander for small scale absorption power and cooling cycle activated by solar energy or waste heat
Mendoza, Luis Carlos; Navarro, Joaquin; Lemort, Vincent ULg et al

Poster (2012, September)

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