Last 7 days
Bookmark and Share    
Full Text
See detailLes inscriptions juives de Venosa
Rochette, Bruno ULg

Scientific conference (2014, May 15)

Detailed reference viewed: 8 (0 ULg)
Full Text
See detailDevelopment of an analytical method to detect simultaneously bisphenols using a multiplexed surface-enhanced Raman scattering quantitative approach
De Bleye, Charlotte ULg; Dumont, Elodie ULg; Sacre, Pierre-Yves ULg et al

Poster (2014, May 15)

Over the last decade, bisphenol A (BPA) attracted a lot of attention. This molecule, commonly used as a precursor to produce epoxy-resin and plastics, is an endocrine disruptor presenting an estrogenic ... [more ▼]

Over the last decade, bisphenol A (BPA) attracted a lot of attention. This molecule, commonly used as a precursor to produce epoxy-resin and plastics, is an endocrine disruptor presenting an estrogenic activity [1]. Despite its health toxicity, BPA is present in a broad variety of consumer goods released from plastic bottles and packaging for example. Since the discovery of its adverse health effect of BPA, the manufacturers tend to use structural analogues of BPA such as BPS, BPF and BPB to produce plastic materials [2]. However, the health safety of these molecules is still not demonstrated. Currently, bisphenols are actively researched and quantified using solid phase extraction and chromatography techniques which are time and solvents consuming. Therefore, it could be very interesting to quantify simultaneously bisphenols using a fast and “green” technique. Surface-enhanced Raman scattering (SERS) exalts dramatically the Raman scattering of molecules adsorbed or very closed to metallic surface enabling to detect very low amounts of analytes while keeping the structural information obtained from the spectrum which is very interesting to consider multiplexed analyses [3-4]. Moreover, SERS, which is a solvent free and fast acquisition technique, is an attractive tool in “Green Chemistry” [5]. In this context, the development of a multiplexed quantitative approach to detect bisphenol was considered. Silver nanoparticles (AgNps) were selected as SERS substrate and their functionalization was investigated taking into account the weak affinity of phenolic molecules for gold and silver surface [6]. Pyridine was selected as surface modifier and allowed to attract bisphenols around metallic surface thanks to hydrophobic interaction and hydrogen bonds [7]. Afterwards, the SERS samples preparation was optimized playing on the concentrations of pyridine and aggregating agent used to get the nanoparticles closer to each other which promotes the SERS effect. Tap water samples were spiked with different concentration of BPA from 5 ppb to 1000 ppb and analyzed using the optimized SERS sample preparation. A good linearity of the response was observed and a calibration curve with coefficient of determination (R2) of 0.9922 was obtained by plotting the intensity of a principal band of BPA versus the concentration. This last step was repeated using BPB as analyte and a calibration curve with a R2 of 0.9991 was obtained for the same range of concentration using a specific band intensity of BPB. Finally, tap water samples were spiked with different concentrations of BPA and BPB simultaneously and analyzed using SERS and it was possible to detect selectively the two molecules thanks to specific bands and a good linearity of the response was observed for both. To conclude, promising results were obtained which pave the way to “green” multiplexed quantitative analyses of very low concentrated analytes using SERS. References: [1] J.-H. Kang et al., Toxicology 226 (2006) 79-89 [2] C. Liao et al., J. Agric. Food Chem. 61 (2013) 4655-4662 [3] K. Kneipp et al., Chem. Rev. 99 (1999) 2957-2975. [4] R.F. Aroca et al., Adv.Colloid Interface Sci. 116 (2005) 45-61. [5] C. De Bleye et al., Talanta 116 (2013) 899-905. [6] X.X. Han et al., Anal. Chem., 83 (2011) 8582-8588. [7] B. San Vicente et al., Anal. Bioanal. Chem. 380 (2004) 115-122. [less ▲]

Detailed reference viewed: 28 (5 ULg)
Full Text
See detailFlowering Goes Underground
Bouché, Frédéric ULg; Lobet, Guillaume ULg; D'Aloia, Maria ULg et al

Conference (2014, May 15)

Flowering is a crucial step in plant life cycle and is therefore tightly controlled by both environmental and endogenous cues. The involvement of the aerial organs of the plant in the molecular mechanisms ... [more ▼]

Flowering is a crucial step in plant life cycle and is therefore tightly controlled by both environmental and endogenous cues. The involvement of the aerial organs of the plant in the molecular mechanisms controlling floral transition has been extensively documented while the participation of the roots remains poorly investigated. However, the induction of flowering by photoperiod involves systemic signals that move in the phloem from leaves to sinks, and hence presumably reach the roots. We therefore performed a transcriptomic analysis of the roots during the induction of flowering in Arabidopsis thaliana and indeed identified a large number of differentially expressed genes. A reverse genetic approach further confirmed the pleiotropic effects of flowering time genes on root architecture. [less ▲]

Detailed reference viewed: 18 (2 ULg)
See detailLes solidarités équivoques de Jean Genet
Denis, Benoît ULg

Conference (2014, May 15)

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailSYMPOSIUM: Activité et cerveau vieillissant - Nature du lien et impact pour la prévention et de l’intervention
Belleville, Sylvie; Adam, Stéphane ULg

in Gériatrie et Psychologie Neuropsychiatrie du Vieillissement (2014, May 15), 12(Supplément 1), 23-25

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailImpact des stéréotypes liés au vieillissement et à la maladie d’Alzheimer sur le vécu des aidants familiaux
Bottard, Aude; Adam, Stéphane ULg; Gilles, Christian et al

Poster (2014, May 15)

INTRODUCTION Dans notre société, les personnes âgées atteintes de la maladie d’Alzheimer sont les cibles à la fois de stéréotypes liés à l’âge, mais aussi de stéréotypes liés à cette maladie (Sartorius ... [more ▼]

INTRODUCTION Dans notre société, les personnes âgées atteintes de la maladie d’Alzheimer sont les cibles à la fois de stéréotypes liés à l’âge, mais aussi de stéréotypes liés à cette maladie (Sartorius, 2003). Leur aidant familial est également souvent touché par l’image négative de la pathologie que les stéréotypes imputent à leur proche (Werner, 2008). Aussi, cette recherche a pour objectif de mieux connaître le point de vue d’aidants familiaux sur la maladie d’Alzheimer et le vieillissement, pour mieux appréhender les implications de ces représentations sur leur vécu. METHODE Un ensemble de questionnaires, dont des mesures de la vision du vieillissement (FSA-R ; Boudjemadi & Gana, 2009) et de la maladie d’Alzheimer (FS-ADS ; Werner et al., 2011), ont été administrés à 38 aidants familiaux dont le proche est atteint de la maladie d’Alzheimer ou d’une démence apparentée. RESULTATS Les analyses statistiques montrent que les individus qui présentent une vision négative du vieillissement sont ceux qui sont aidants depuis plus longtemps. Par ailleurs, les personnes qui ont un vécu négatif de la maladie (qui ont honte de leur proche ou qui sentent que les autres ont honte de lui), sont ceux qui se sentent moins compétents en tant qu’aidant. De même, le fait d’avoir peur de son proche, est associé à un épuisement physique et émotionnel, ainsi qu’à une humeur triste et anxieuse. CONCLUSION Les stéréotypes liés à l’âge et à la maladie péjorent plusieurs éléments du vécu de l’aidant (santé, sentiment de compétence, expérience en tant qu’aidant.). En conséquence, il importe d’encourager la déconstruction des stéréotypes et idées reçues véhiculés par la société, notamment par le biais de programmes d’aide aux aidants [less ▲]

Detailed reference viewed: 31 (0 ULg)
Full Text
See detailDevelopment and numerical validation of a 2-scale computational model to study the mechanical behavior of nanocrystalline metals
Péron, Vincent ULg

Doctoral thesis (2014)

This work aims at predicting the mechanical behavior of nanocrystalline structure using a 2-scale approach. Molecular simulations using the quasicontinuum method (QC) are performed to obtain the ... [more ▼]

This work aims at predicting the mechanical behavior of nanocrystalline structure using a 2-scale approach. Molecular simulations using the quasicontinuum method (QC) are performed to obtain the mechanical responses of the grain-boundaries and grains at the nanoscale. A finite element model is then calibrated using these atomistic results. This 2-scale model accounts for intergranular and intragranular plasticity, can predict the intergranular failure, and is able to study large structures. [less ▲]

Detailed reference viewed: 35 (15 ULg)
Full Text
See detailEvaluation de l'effet antidiabétique de l'huile du figuier de barbarie (Opuntia ficus-indica (L.) Mill.) (Communication orale)
Berraouan, A.; Mekhfi, H.; Ziyyat, A. et al

Scientific conference (2014, May 15)

Detailed reference viewed: 18 (3 ULg)
Full Text
Peer Reviewed
See detailDiscrimination of two geographically distinct populations of sea bass Dicentrarchus labrax, using stable isotopic signatures of mercury (δ202Hg, Δ199Hg)
Cransveld, Alice ULg; Amouroux, David; Koutrakis, Emmanuil et al

Poster (2014, May 15)

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on ... [more ▼]

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on mercury's biogeochemical cycle at both local and global scale. In the present work, we investigate the possibility to use mercury isotopic signature in fish as a tool to discriminate different polluted areas and potential pollution sources. Indeed, Hg can exhibit both mass-dependent (MDF) and mass-independent fractionation (MIF). While MDF may occur during biological cycling inter alia and could be used to understand bioaccumulation processes, MIF provides a unique fingerprint of specific chemical pathways, such as photochemical transformations. In this context, information provided by Hg isotopes would help to improve environmental management strategies. A preliminary set of four and ten juvenile common sea bass, Dicentrarchus labrax were collected from the North Sea and the Aegean Sea respectively. T-Hg was analysed by direct mercury analyser (DMA), speciation by gas chromatography inductively coupled plasma mass spectrometer (GC-ICP-MS) and Hg isotope analysis were performed using cold vapour generation with multicollector ICP-MS. Total Hg concentrations in all tissues were higher in individuals from the North Sea ( Hgtot muscle=1,14 ± 0,48 mg.kg-1 dw) than from Greece (0,60 ± 0,06 mg.kg-1 dw). Speciation analysis shows that MeHg is the predominant form of Hg in muscle (89% MeHg on average) but not in liver (51% MeHg on average). Isotopic mass dependent values (δ202Hg) values were always higher in muscle than in liver and related to Hg species distribution. For mass independent isotopic signature, sea bass from the Aegean Sea had a systematically higher Δ199Hg value than individuals from the North sea (e.g.: 0,56 ± 0,05‰ and 0,32 ± 0,06‰ respectively in muscle). While mass dependent isotopic signature probably reflects some internal Hg metabolism, mass independent isotopic signature seems definitely site dependent. Such isotopic discrimination might be in agreement with difference in both mercury sources and cycling in the North and Aegean Seas. These preliminary results indicate that Hg isotopes may thus help to discriminate fish from different areas. This promising outcome must be further confirmed by extending the number of individuals and locations to be investigated. [less ▲]

Detailed reference viewed: 22 (0 ULg)
Full Text
See detailIdentification de la composition en arômes des miels de la région orientale du Maroc (Communication orale)
Abeslami, Azzedine; Fauconnier, Marie-Laure ULg; Sindic, Marianne ULg et al

Scientific conference (2014, May 15)

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailHow to build a biological linker dedicated to the engineering of novel drug delivery systems
Crasson, Oscar ULg; Galleni, Moreno ULg; Parente, Raffaella et al

Poster (2014, May 15)

Nowadays, chemical linkages are widely used in industry to coat bioactive molecules on biocompatible supports. However, some issues inherent to the linkage procedure remain. For example, chemical ... [more ▼]

Nowadays, chemical linkages are widely used in industry to coat bioactive molecules on biocompatible supports. However, some issues inherent to the linkage procedure remain. For example, chemical reactions often damage the structure and therefore the activity of the immobilized molecules. In this work, we propose the use of a human chitin binding domain (ChBD) to immobilized bioactive molecules on a polysaccharide-based surface. ChBD belongs to the human chitinase called chitotriosidase and was shown to interact specifically with chitin and chitooligomers. Using molecular biology and protein engineering, we have developped of a new biological tool based on the hybrid protein technology. In this technology, we can create chimeric proteins that have the ability to bind polysaccharidic supports thanks to their binding domain that can be covalently linked with any bioactive molecule that can confer prophylactic or therapeutic activities. In this study, we have successfully shown that we can use the chitin binding domain (ChBD) from the human chitotriosidase as a biological linker dedicated to the engineering of novel drug delivery systems containing chitin or other analogous polysaccharides. [less ▲]

Detailed reference viewed: 35 (7 ULg)
Full Text
See detailIdentifying root-secreted proteases in Arabidopsis thaliana: an Activity-Based Protein Profiling approach.
Lallemand, Jérôme ULg; Périlleux, Claire ULg; Tocquin, Pierre ULg

Poster (2014, May 15)

Proteases are involved in many physiological processes during the whole life of the plant, such as embryonic development, defense against pathogens, nutrition or mycorrhiza creation. However, the ... [more ▼]

Proteases are involved in many physiological processes during the whole life of the plant, such as embryonic development, defense against pathogens, nutrition or mycorrhiza creation. However, the functions of many of the 800 proteases of Arabidopsis thaliana still remain unknown. Besides discovering new functions, studying proteases can also result in improving plant biotechnology. Indeed, plants can be used as hosts for recombinant protein production. Some proteins of interest require to be secreted in order to fold properly, but production yields are limited due to their degradation by endogenous extracellular proteases. The aim of our study is to identify active root-secreted proteases of Arabidopsis thaliana. Their activity was first analyzed by in vitro incubation with a target protein (BSA) at different values of pH and in the presence of proteases inhibitors. This analysis identified serine proteases as the major protease class involved in BSA degradation. Then, an Activity-Based Protein Profiling approach led to the labeling of two active serine proteases in the root-secreted sample. Finally, a further step towards the identification by mass spectrometry, based on affinity purification, was developed. [less ▲]

Detailed reference viewed: 54 (3 ULg)
Full Text
Peer Reviewed
See detailMaize cold tolerance : in search of relevant parameters for discriminating genotypes
Riva-Roveda, Laetitia ULg; Escale, Brigitte; Giauffret, Catherine et al

Poster (2014, May 15)

Detailed reference viewed: 11 (2 ULg)
Full Text
See detailQualitative and quantitative analyses of a pharmaceutical formulation produced by hot melt extrusion using Raman spectroscopy
Netchacovitch, Lauranne ULg; De Bleye, Charlotte ULg; Sacre, Pierre-Yves ULg et al

Poster (2014, May 15)

In the pharmaceutical industry, Hot Melt Extrusion (HME) is a recent technique used to integrate poor water soluble drugs in pharmaceutical formulations. Indeed, more and more active pharmaceutical ... [more ▼]

In the pharmaceutical industry, Hot Melt Extrusion (HME) is a recent technique used to integrate poor water soluble drugs in pharmaceutical formulations. Indeed, more and more active pharmaceutical ingredients (API) belong to the Biopharmaceutical Classification System (BCS) II and IV. Their integration in pharmaceutical solid forms is a big deal. HME processes increase the bioavailability and the solubility of those API by encompassing them in a polymeric carrier and by forming solid dispersions [1]. Moreover, in 2004, the FDA’s guidance initiative promoted the usefulness of Process Analytical Technology (PAT) tools when developing a manufacturing process. Vibrational spectroscopy is an appropriate PAT tool to analyze extrudates [2 – 3]. In this case, Raman spectroscopy, which belongs to vibrational spectroscopy, was used to analyze itraconazole extrudates qualitatively and quantitatively. During HME, the main objective is to develop solid dispersions by converting a crystalline API in an amorphous one, in order to improve its solubility and bioavailability [4]. According to Raman spectra, it is possible to identify the polymorphic form of the components in the extrudates by integrating or rationing the Raman bands that are characteristic of the API or by calculating the width at half intensity of some bands [5]. After determining the polymorphic form of the API, a quantitative method was developed in order to measure the ratio between the API and the polymer. Finally, chemical imaging was performed on extrudates to identify the distribution of the homogeneity of the API inside the polymer [6]. In conclusion, Raman spectroscopy is an appropriate tool to follow an extrusion process. By qualitative and quantitative analyses it is possible to determine the composition, the polymorphic form, the homogeneity, and the concentration of pharmaceutical matrices according to Raman fingerprint. References: [1] S. Shah et. al., Int J Pharm 453 (2013) 233 – 252. [2] L. Saerens et. al., Anal Chem 85 (2013) 5420 – 5429. [3] T. De Beer et. al., J Pharm Biomed Anal 48 (2008) 772 – 779. [4] A. Sarode et. al., Eur J Pharm Sci 48 (2013) 371 – 384. [5] E. Widjaja et. al., Eur J Pharm Sci 42 (2011) 45 – 54. [6] J. M. Amigo, Anal Bioanal Chem 398 (2010) 93 – 109. [less ▲]

Detailed reference viewed: 20 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence du broyage mécanique sur la taille et les paramètres texturaux de particules de xérogels de carbone
Piedboeuf, Marie-Laure ULg; Léonard, Alexandre ULg; Traina, Karl et al

Conference (2014, May 15)

Les xérogels de carbone sont des candidats prometteurs pour une utilisation dans de nombreux domaines tels que le stockage de l’énergie électrochimique (anodes pour batteries Li-ion ou supercondensateurs ... [more ▼]

Les xérogels de carbone sont des candidats prometteurs pour une utilisation dans de nombreux domaines tels que le stockage de l’énergie électrochimique (anodes pour batteries Li-ion ou supercondensateurs), l’adsorption ou en tant que supports de catalyseurs (dont les électrocatalyseurs de pile à combustible PEM, par exemple) [1]. En plus de leur grande pureté, un des avantages principaux des xérogels de carbone est de pouvoir contrôler leur texture poreuse notamment via les conditions de synthèse [2, 3]. Ce sont les étapes de séchage et de pyrolyse qui permettent de moduler la texture finale des matériaux obtenus. Après vieillissement, les mélanges aqueux résorcinol-formaldéhyde mènent à des gels polymères susceptibles d’être convertis en polymères secs après séchage sous vide et, in fine, en xérogels de carbone après pyrolyse sous atmosphère inerte. Au cours de ces étapes, les produits obtenus restent cependant sous forme monolithique. Dans le cadre des applications pré-citées (catalyse, stockage électrochimique ou adsorption), il est néanmoins nécessaire de réduire les pièces monolithiques en particules de dimensions appropriées pour l’application cible. Dans ce cas, une étape clé est de pouvoir contrôler leur taille finale. Le comportement à l’attrition de matériaux présentant différentes textures poreuses a été étudié en détail. Les broyages ont été effectués dans un broyeur planétaire en conditions sèche ou humide sur des gels polymères secs ainsi que sur des xérogels de carbone obtenus après pyrolyse à 800°C. La granulométrie laser à diffraction lumineuse ainsi que la microscopie électronique à balayage ont été utilisées afin d’évaluer la distribution des tailles particulaires de la poudre broyée. Les résultats indiquent que la texture poreuse des matériaux, leur nature (polymère ou carbone) et leur dureté sont des facteurs significatifs qui influencent fortement les mécanismes de comminution/fragmentation lors du broyage, en particulier si l’on considère les xérogels de carbone. En effet, il apparait que le broyage par voie sèche de polymères secs (avant pyrolyse) semble être la manière la plus efficace pour obtenir une distribution de taille de particules homogène pour toutes les textures poreuses étudiées. Dans les conditions de broyage employées, il est possible d’obtenir des particules carbonées présentant une distribution de taille de particules centrée sur 10 µm, avec rétention de la texture mésoporeuse. Les résultats de cette recherche montrent également la possibilité d’utiliser la porosimétrie à intrusion de mercure en tant qu’outil pour évaluer simultanément la taille des mésopores ainsi que la taille des particules de matériaux broyés. 1. Yuan, X., Y.-J. Chao, Z.-F. Ma and X. Deng, Electrochemistry Communications, 9(10), 2591-2595 (2007). 2. Job, N., R. Pirard, J. Marien and J.-P. Pirard, Carbon, 42(3): p. 619-628 (2004). 3. Scherdel, C., R. Gayer and G. Reichenauer, J Porous Mater, 19(3): p. 351-360 (2012).  [less ▲]

Detailed reference viewed: 24 (4 ULg)