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See detailTemperature Adaptation of Proteins: Stability, Folding and Flexibility in Mesophilic-like Engineered Alpha-Amylases
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2009, July 02)

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold ... [more ▼]

Habitats of permanently cold temperature, like polar regions for example, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently in these cold environments. According to the hypothesis developed in our laboratory, the adaptation to cold temperature involves relationships between activity, flexibility and stability. Even if activity and stability are not physically linked in proteins 1, the consensus for the adaptive strategy is to take advantage of the lack of selective pressure for stable proteins to lose stability, therefore increasing the flexibility or mobility of the enzyme at low temperatures that restrict molecular motions. 2 Working on alpha-amylase, we have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis. We have built two multiple-mutants (Mut5 and Mut5CC) of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium, Pseudoalteromonas haloplanktis. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic chloride-dependant homolog from pig pancreas, PPA. The study of selected single mutations prompt us to construct two multiple-mutants, Mut5 and Mut5CC, carrying 5 and 6 additional weak interactions found in PPA, that showed an increased stability and a lower activity at 25 °C.3 We have compared AHA, Mut5 and Mut5CC with additional methods like differential scanning calorimetry, thermal and chemical unfolding and circular dichroism in order to determine the gain in stability. We also studied the flexibility or breathing of the enzymes by acrylamide-induced fluorescence quenching. The newly introduced weak interactions stabilized the proteins, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. These results and those of the previous work 3, unambiguously support the capital role of weak interactions in the balance between activity, flexibility and stability and provide a better knowledge of the adaptation of enzymes to cold temperatures. [less ▲]

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See detailBehavior of omega-3 fatty acids in eggs during cooking
Douny, Caroline ULg; El Khoury, Rawad ULg; Degand et al

Poster (2009, July 01)

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See detailFinding miRNAs able to regulate angiogenesis
Pendeville, Helene; Nivelles, Olivier ULg; Malvaux, L. et al

Poster (2009, July)

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See detailVHHs as model proteins to investigate amyloid fibril formation
Chavignon, Chloé ULg; Pardon, Els; Wyns, Lode et al

Poster (2009, July)

The term "amyloidosis" covers up a group of diseases associated with deposition in different organs of protein aggregates organized into amyloid fibrils. About twenty-five amyloidosis are known so far ... [more ▼]

The term "amyloidosis" covers up a group of diseases associated with deposition in different organs of protein aggregates organized into amyloid fibrils. About twenty-five amyloidosis are known so far, amongst which Alzheimer's disease, type II diabetes and immunoglobulin amyloidosis [1]. Although the mechanism of amyloid fibrils formation at the molecular level is not yet completely understood, it has been shown that the capacity to form amyloid fibrils in vitro is an intrinsic property of all polypeptide chains [1]. The choice of model proteins to investigate the aggregation process in vitro is therefore no more restrained to proteins involved in amyloidosis but can be settled on a wide variety of proteins. In this study, we have chosen two variable domains of camelid heavy-chain antibodies (referred to as VHHs or nanobodies), cAb-HuL6 and cAb-BcII10, and this choice was motivated by the following reasons: - First, they are small monomeric domains (~14 kDa) presenting high stability and high solubility [2], which permits their expression with a high yield (20-40 mg.L-1). - Second, a wide range of stable mutants of these two VHHs is available. Mutations located at the disulfide bond [3,4], the CDRs [3] and the framework have been introduced. Characterisation of the aggregating properties of these mutants will allow the investigation of the impact of these structural elements on the process of fibril formation. In order to determine conditions in which cAb-HuL6 and cAb-BcII10 are more susceptible to form intermediates and thus amyloid fibrils, heat induced infolding experiments at pHs comprised in a range from 2,5 to 9,5 have been monitored by intrinsic fluorescence, ANS binding and circular dichroism. Then, aggregation experiments have been performed in the selected conditions and the presence of amyloid fibrils has been acknowledged by thioflavineT fluorescence experiments and electronic microscopy. [1] Chiti, F. and Dobson, C. M., Protein misfolding, functional amyloid, and human disease, Annu. Rev. Biochem., 75, 2006, 333-366. [2] Dumoulin, M., Conrath, K., Van Meirhaeghe, A., Meersman, F., Heremans, K., Frenken, L. G., Muyldermans, S., Wyns, L. & Matagne, A., Single-domain antibody fragments with high conformational stability, Protein Sci., 11, 2002, 500-515. [3] Saerens, D., Pellis, M., Loris, R., Pardon, E., Dumoulin, M., Matagne, A., Wyns, L., Muyldermans, S., Conrath, K., Identification of a universal VHH framework to graft non-canonical antigen-binding loops of camel single-domain antibodies, J. Mol. Biol., 352, 2005, 597-607. [4] Saerens D., Conrath K., Govaert J., Muyldermans S., Disulfide bond introduction for general stabilization of immunoglobulin heavy-chain variable domains, J Mol Biol., 377, 2008, 478-488. [less ▲]

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See detailPerceived logistics service quality driven store Loyalty
Hammedi, Wafa ULg; Van Riel, Allard ULg; Semeijn, Janjaap

Poster (2009, July)

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See detailPyropheophorbide-a-methyl ester: DMPC liposome vectorization and biophysical properties for PDT
Guelluy, Pierre-Henri ULg; Fontaine-Aupart, Marie-Pierre; Grammenos, Angeliki ULg et al

Poster (2009, July)

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See detailMeasure of nursing time interventions for hospitalized elderly patients
THONON, Olivier ULg; GILLAIN, Daniel ULg; SERMEUS, Walter et al

Poster (2009, July)

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See detailEvolution of floodplain sedimentation during the last millennia in the Ardenne Massif (Belgium)
Houbrechts, Geoffrey ULg; Notebaert, Bastiaan; Verstraeten, Gert et al

Poster (2009, July)

In the Ardenne massif, several periods of increased sediment deposition have been identified during the last millennia. They can be correlated to increasing anthropogenic land use pressure. The majority ... [more ▼]

In the Ardenne massif, several periods of increased sediment deposition have been identified during the last millennia. They can be correlated to increasing anthropogenic land use pressure. The majority of the sediments found in floodplains were deposited in the last 4000 years, and in many cases even in the last 1000 years. In the Amblève catchment, the first increase in sediment deposition of the Holocene occurred during the Bronze Age (3200 BP), related to first deforestations and crop cultures in the area. Several organic depositions have occurred between 2700 BP and 1000 BP and probably indicate low anthropogenic pressures or more humid periods. From the 11th century onwards, there was an increase in sedimentation, and alluvial deposits contain more charcoal. A second important increase in sedimentation is observed in headwater catchments at the end of the 14th century, which can be related to the development of many iron factories. In the Ardenne massif, more than 300 iron factories existed between the 14th and the 19th century and about 20 ha of forest were cleared each year for the consumption of a refining forge or a blast furnace. Analysis of slag concentration produced in former factories and redistributed in the floodplain allows us to reconstruct the evolution of floodplains since the inception of the iron industries. The results show that not all floodplains in the Amblève catchment are equally sensitive to catchment disturbances. In the headwater stream (Chavanne river, 10-20 km²), about 80 cm of sediment has been deposited since the inception of the iron industries (towards 1540 AD). In the lower Lienne valley (100-150 km²), almost no sediment accumulation occurred in the floodplains after the beginning of iron melting (towards 1400 AD). This difference could be explained by the larger stream power of the Lienne river (100-120 W/m2 for Qb). [less ▲]

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See detailBedload progression in gravel bed rivers using iron slag as a tracer
Houbrechts, Geoffrey ULg; Levecq, Yannick; Mols, Julien et al

Poster (2009, July)

In fluvial dynamics studies, different methods are used to evaluate bedload transport and particle travel lengths. However, results are mostly based on a few transported elements and on a relatively short ... [more ▼]

In fluvial dynamics studies, different methods are used to evaluate bedload transport and particle travel lengths. However, results are mostly based on a few transported elements and on a relatively short time scale. Consequently, it is difficult to extrapolate these results to whole bedload, because of the burying of particles into the subsurface layer or the trapping of elements in fluvial forms (point bars, riffles, …), which can immobilise elements during long periods. Bedload progression has been evaluated in Ardenne rivers using slag elements produced by the past factories established along rivers between the 14th and the 19th centuries. Important quantities of slag were dumped close to rivers or even directly into channels. For several centuries, slag elements were dispersed in the bedload and transported by floods of varying importance. Consequently, slag can be considered as a tracer to analyze bedload progression over several centuries. The size of slag elements has been studied in many Ardenne rivers. The longitudinal size trend of the largest slag particles allows us to determine the effective competence of rivers and to analyze the hydraulic sorting. Moreover, downstream of some metallurgic sites, we have constrained the presence of slag elements to the most downstream riffles. Because we know from historical studies the periods of activities of these sites, we may estimate the speed of bedload progression in several gravel bed rivers from the Ardenne Massif (2-3 km/century). [less ▲]

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See detailEvolution of blood myeloperoxidase in the perioperative period of horses undergoing emergency celiotomy.
Salciccia, Alexandra ULg; Grulke, Sigrid ULg; de la Rebière de Pouyade, Geoffroy ULg et al

Poster (2009, July)

Colic can cause an activation of neutrophils with release in the blood flow of myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to describe the evolution ... [more ▼]

Colic can cause an activation of neutrophils with release in the blood flow of myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to describe the evolution of plasma MPO after colic surgery. Materials included 13 adult horses that underwent an emergency celiotomy for acute intestinal obstruction. Venous blood samples were collected into EDTA anticoagulated tubes before surgery, during surgery after correction of the intestinal lesion and during the recovery of anaesthesia. In the postoperative period samples were taken every 4 hours during the first 4 days (from day 0 until day 4), every 12 hours during the days 4 and 5 and every 24 hours until day 10. MPO was assayed with a specific enzyme-linked immunosorbent assay. Statistical analysis was performed by one way Anova with student- Newman-Keuls post test on data obtained for each time point. Significance was set at p < 0.05. The horses were operated for an obstruction strangulated or not of the small or the large intestine. In six cases the postoperative period was uneventful, the 7 remaining developed one or 2 severe complications. Eight horses were discharged and 5 died during the hospitalization.The general aspect of the curve of mean plasmatic MPO can be described as follow: An increase was observed from the admission on until a peak of concentration occurring generally during the time of recovery from the anaesthesia with the highest mean value reaching 740.84 +/- 507.61ng/ml. This was followed by a progressive decrease until the lowest value, usually near to day 2 after the recovery from anaesthesia corresponding to 171.79 +/- 76.21 ng/ml of MPO. Afterwards, the mean concentrations increased slowly until postoperative day 10. In the majority of cases a stable and low MPO value (plateau) was observed during approximately 2 days (from day 1 to day 3 postoperatively).The initial peak of MPO after surgery could be associated to the neutrophil activation consequent to the intestinal disorder and the intense stimulation of the coeliotomy. The following significant reduction in concentration could be attributed to MPO infiltration into the tissues with a critical point at approximately 2 days after surgery. This study may contribute to a better understanding of the role of the MPO and neutrophils in the pathophysiology of horses in the postoperative period after colic surgery. [less ▲]

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See detailInsights into the plant defense mechanisms induced by Bacillus lipopeptides.
Ongena, Marc ULg; Henry, Guillaume ULg; Adam, Akram et al

Poster (2009, July)

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See detailTime reversal of Bose-Einstein condensates
Martin, John ULg; Georgeot, Bertrand; Shepelyansky, Dima

Poster (2009, July)

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See detailUn outil d’aide à la décision pour la gestion des chablis en Région wallonne (Belgique)
Riguelle, Simon ULg; Hebert, Jacques ULg; Jourez, Benoît ULg

Poster (2009, June 30)

The poster highlights the main steps leading to the development of a decision-support tool for storm damage management by the forest sector at a regional scale.

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See detailQuelles sont les espèces d’oiseaux indicatrices de la qualité des forêts feuillues ardennaises ?
Delahaye, Laurence; Rondeux, Jacques ULg

Poster (2009, June 29)

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See detailScabies in a llama (Lama glama): control with moxidectin long acting (Cydectin®LA)
Caron, Yannick ULg; Cavadino, Céline; Losson, Bertrand ULg

Poster (2009, June 29)

An adult neutered male llama (Lama glama) was presented for examination with a history of a severe long lasting (3 years) and recurrent itch and crust formation. Three years ago, scabies had been ... [more ▼]

An adult neutered male llama (Lama glama) was presented for examination with a history of a severe long lasting (3 years) and recurrent itch and crust formation. Three years ago, scabies had been diagnosed by a local vet on the basis of clinical signs; the animal was treated several times with ivermectin (Ivomec®) injectable and phoxim (Sarnacuran®). After each treatment there was a marked clinical improvement but relapse was the rule within 1 to 2 months. During the two years preceeding our first visit the animal had received local applications of Sarnacuran every two to three weeks wich resulted in incomplete control. None of the owners had reported skin lesions compatible with scabies. On February 27th 2009 the animal showed a marked pruritus accompanied by very thick scabs and alopecia on the face (around the mouth and ears), shoulders, forelegs, hindlegs, abdomen, flanks and the tail. Clinical examination revealed a fairly good general condition. Abnormalities were limited to the skin. Skin scrapings were taken and numerous Sarcoptes scabiei mites were subsequently detected microscopically. Sedation and analgesia were performed via the intramuscular administration of xylazine (Vexylan®) at 0.5 mg/kg. The scabs were humidified with a camomile infusion and a maximum of material was removed and destroyed. Then the llama was treated with 10% moxidectin (Cydectin LA®) at 1 mg/kg by subcutaneous injection at the basis of the ear. On April 6th 2009, a very marked clinical improvement was observed: most of the scabs had dissapeared and hair regrowth in previously alopecic area was observed. Skin scrapings were negative. However, some pruritus was still observed and a second treatment with Cydectin LA was given. According to the owner who was contacted by phone in early May the clinical condition of the animal has further improved. A final visit is planned to assess the clinical and parasitological cure in this S. scabiei infected llama. At our knowledge, this is the first time Cydecin LA is used in llama for the treatment of scabies. [less ▲]

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See detailEvaluation de la fonction récréative des massifs forestiers wallons
Colson, Vincent ULg; Lejeune, Philippe ULg; Rondeux, Jacques ULg

Poster (2009, June 29)

Estimer la valeur économique des visites effectuées à des fins récréatives en forêt wallonne.

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See detailProduction of polymer/clay nanocomposite foams with improved fire behaviour using supercritical fluid technology
Urbanczyk, Laetitia ULg; Calberg, Cédric ULg; Detrembleur, Christophe ULg et al

Poster (2009, June 19)

In this study, supercritical CO2 is successfully used as foaming agent to prepare poly(styrene-co-acrylonitrile) (SAN) foams containing a low amount of well-dispersed nanoclay (5wt%). This kind of ... [more ▼]

In this study, supercritical CO2 is successfully used as foaming agent to prepare poly(styrene-co-acrylonitrile) (SAN) foams containing a low amount of well-dispersed nanoclay (5wt%). This kind of nanofiller has an influence both on material cellular morphology and fire property. In fact, SAN foam filled with nanoclay has smaller cells and higher density compared to unfilled foam. Moreover, the nanocomposite foam burns more slowly and without producing any burning droplets, which is highly desirable when considering housing applications. [less ▲]

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See detailThe diversity of Clostridial hydrogenases and biohydrogen production
Calusinska, Magdalena ULg; Savichtcheva, Olga; Masset, Julien ULg et al

Poster (2009, June 18)

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean ... [more ▼]

Molecular hydrogen is a key intermediate in metabolomic interactions of a wide range of microorganisms. Hydrogen is also regarded as a key component in future energy systems as it is a sustainable, clean, and transportable energy carrier. Some microorganisms can produce hydrogen during a reversible reduction of protons to dihydrogen, a reaction which is catalyzed by hydrogenases [1]. Hydrogenases belong to an iron – sulphur protein family, that contains active sites consisting of inorganic sulfide and iron atoms bound to the polypeptide chain. On the basis of their bimetallocenter composition hydrogenases are divided into three main groups, phylogenetically not related: [NiFe] hydrogenases, [Fe] only hydrogenases and ‘metal – free hydrogenases’ which were described in methanogenic Archaea only. [NiFe] hydrogenases, composed of at least two subunits are well characterized and widely distributed between Archaea and Bacteria but only a few representatives of Clostridium possess this type of enzyme. On the other hand, [Fe] only hydrogenases, being usually monomeric enzymes and restricted to Bacteria and a few eukaryotic species are far less described. These proteins, being omnipresent catalysts of many biological reactions, are especially abundant in Clostridia. The physiological function of Clostridial [Fe] only hydrogenases is to dispose under the form of hydrogen, of the excess of reducing power generated during the fermentation of carbohydrates. The unusual diversity of forms of [Fe] only hydrogenases within Clostridia seems to support the central role of this enzyme in cell metabolism and to facilitate the quick adaptation of the host to changing environmental conditions. Moreover, the presence of multiple putative operons encoding for multisubunit [Fe] only hydrogenases in the genomes of sequenced Clostridium spp. is highlighting the need to study the new, not yet described function of these ostensibly simple proteins. In this project, we have focused our effort on the molecular characterization of key enzymes involved in the process of biohydrogen production with a special interest in Clostridium species. By applying molecular techniques on samples from different kinds of bioreactors, we want to select highly productive species in terms of hydrogen generation. We also believe that gene expression profiling will provide new data on the possible function and activity of different hydrogenases involved in the process. The better understanding of hydrogen metabolism is essential for its sustainable production. [less ▲]

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See detailEDLC electrodes from cellulose-based carbon aerogels : influence of the carbon's surface chemistry
Hildenbrand, Claudia; Grzyb, B.; Berthon-Fabry, S. et al

Poster (2009, June 14)

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See detailDevelopment of multilayered chitosan-based nanofibers
Croisier, Florence ULg; Aqil, Abdelhafid ULg; Detrembleur, Christophe ULg et al

Poster (2009, June 14)

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method ... [more ▼]

By combining electrospinning and layer-by-layer deposition techniques, new porous material scaffolds of multilayered, chitosan-based nanofibers were produced. Layer-by-layer (LBL) is a well-known method for surface coating, based on electrostatic interactions. It enables the controllable deposition of a variety of polyelectrolytes including synthetic and natural materials, with designable layer structure, defined layer thickness and size. Electrospinning (ESP) allows the fabrication of polymer fibers ranging from nanometers to a few microns in diameter, depending on the polymer characteristics (a.o. molecular weight, solution viscosity and conductivity) and processing conditions (electric potential, distance between syringe-capillary and collection plate, concentration, flow rate). Mats of nanofibers produced by ESP display a very large surface area-to-volume ratio and high porosity with very small pore size. The nanometric scale of electrospun fibers also proves a positive effect on cellular growth, as fiber mats mimic extracellular matrix structure. The association of these two techniques with the use of biocompatible and biodegradable polymers such as chitosan, gives outstanding prospects in the field of biomedical applications, especially for the preparation of wound dressings, artificial skin or tissue engineering scaffolds. In the present study, a charged copolymer, poly(methylmethacrylate-block-methacrylic acid), was added to a poly(ε-caprolactone) or poly(D,L-lactide) solution before electrospinning in order to prepare surface charged nanofibers. Oppositely charged polyelectrolytes – chitosan and poly(styrene sulfonate) or hyaluronic acid – were then alternately deposited on these aliphatic polyester fiber “cores” using LBL method. The aliphatic polyester core was also removed selectively to confirm the growth of a multilayered shell, obtaining hollow fibers. [less ▲]

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See detailNovel Amphiphilic copolymers and design of smart nanoparticule for triggered drug delivery systems
Cajot, Sébastien ULg; Jérôme, Christine ULg

Poster (2009, June 14)

Over the last decade, polymer micelles attracted an increasing interest in drug pharmaceutical research because they could be used as efficient drug delivery systems. Micelles of amphiphilic block ... [more ▼]

Over the last decade, polymer micelles attracted an increasing interest in drug pharmaceutical research because they could be used as efficient drug delivery systems. Micelles of amphiphilic block copolymers are supramolecular core-shell type assemblies of tens of nanometers in diameter. In principle, the micelles core is usually constructed with biodegradable hydrophobic polymers such as aliphatic polyesters, e.g. poly(epsilon-caprolactone) (PCL), which serves as a reservoir for the incorporation of various lipophilic drugs. Water soluble poly(ethylene oxide) (PEO) is most frequently used to build the micelle corona because it is very efficient in preventing protein adsorption at surfaces and in stabilizing the micelles in the blood compartment, giving rise to particles invisible to the body defence system (so-called stealthy or long circulating particles). Improvements of such simple systems however, rely on the development of novel chemistries and materials by advanced macromolecular engineering techniques. The tumour targeting of a cytotoxic agent refers to the passive accumulation of polymer nanocarriers to solid tumours (EPR effect) followed by active internalization in tumor cells. The internalization of the drug is required for cell death because most cytotoxic drugs act intracellularly. Accordingly, polymer micelles are usually modified by specific ligands. However, these ligands can decrease the micelles stealthiness and stability. No-specific ligands can be used if their exposition is modulated by the pH decrease typical of tumour tissues. Lipophilic drugs are generally incorporated in the hydrophobic core of the micelles. The release of the drug is ruled by diffusion and degradation of the biodegradable polymer used as reservoir. Even if micelles get a high stability in aqueous media thanks to their low critical micellar concentration, the dissociation of micelles is not always preserved when they are injected in the blood compartment. The cross-linking of the core of micelles by disulfide bridges will provide the stability of micelles after the administration and will release the drugs intracellularly by enzymatic breaking of disulfide bridges. This work consists in the development of new macromolecular architectures for the targeting of tumour cells. pH sensitive copolymers able to micellize so as non-specific ligand like biotin is exposed on their surface in response to pH decrease typical for tumour tissues will be synthesized by the incorporation of pH-sensitive linkers like hydrazone or imine benzoïc linkers. In addition, the core of these new micelles will be cross-linked by disulfide bridges to prevent dissociation around healthy cells and trigger the drug release inside tumour cells. [less ▲]

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See detailDesign of thermoresponsive magnetic nanoparticles for hyperthermia
Sibret, Pierre ULg; Aqil, Abdelhafid; Jérôme, Christine ULg

Poster (2009, June 14)

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See detailEvolution of the surface chemistry of carbon xerogels with very different textural properties by chemical activation and oxidation
Zubizarreta, Leire; Arenillas, A.; Pirard, Jean-Paul ULg et al

Poster (2009, June 14)

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See detailIN VITRO CLONAL PROPAGATION OF A PROMISING AGROFUEL PRODUCING-PLANT : JATROPHA CURCAS L.
Medza Mve, Samson Daudet ULg; Mergeai, Guy ULg; Baudoin, Jean-Pierre ULg et al

Poster (2009, June 13)

In the present investigation, in vitro clonal propagation of two-month-old Jatropha curcas L. was achieved employing nodal explants. Axillary shoot bud proliferation was best initiated on Murashige and ... [more ▼]

In the present investigation, in vitro clonal propagation of two-month-old Jatropha curcas L. was achieved employing nodal explants. Axillary shoot bud proliferation was best initiated on Murashige and Skoog’s (MS) basal medium supplemented with N6-benzyladenine (BA) and adenine sulphate. This medium allowed the production of 3.1 ± 0.5 shoots per nodal explant with 3.5 ± 0.8 cm average length after 3-4 weeks. [less ▲]

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See detailA risk-based approach for designing climate-proof flood protection
Ernst, Julien ULg; Dewals, Benjamin ULg; Detrembleur, Sylvain ULg et al

Poster (2009, June 12)

In the framework of the Belgian national research project “ADAPT - Towards an integrated decision tool for adaptation measures”, a risk-based decision-support system (DSS) is developed with the aim of ... [more ▼]

In the framework of the Belgian national research project “ADAPT - Towards an integrated decision tool for adaptation measures”, a risk-based decision-support system (DSS) is developed with the aim of selecting the most cost-effective flood protection strategies. Based on detailed 2D hydraulic modelling combined with high resolution and high accuracy land use database as well as socio-economic datasets, integrated risk analysis is conducted to evaluate the benefits of different flood protection measures. The tool is dedicated to the integrated evaluation of flood management strategies in the context of increased flood risk as a result of climate change, considering hydraulic, economic, social as well as environmental parameters to quantify both the benefits (in terms of avoided risk) and the cost of each strategy. While such risk analyses are mostly undertaken at a macro- or meso-scale, the present approach is performed at a micro-scale, meaning that the considered assets are the individual buildings or facilities. The methodology relies on a consistent approach in terms of accuracy of input data, hydraulic modelling and expected results. Indeed, besides detailed hydraulic modelling conducted on computational grids as fine as 2m by 2m, exploited data include laser altimetry (LIDAR), high resolution and high quality land use maps as well as other complementary vector geographic datasets providing socioeconomic information at a micro-scale. Next to the flow modelling and the exposure analysis conducted for each building or facility individually, the procedure involves social impact analysis (accounting for social vulnerability and adaptive capacity of communities) and the evaluation of direct economic damage based on different relative damage functions. The outcomes of this risk analysis are subsequently exploited in the DSS to evaluate the effectiveness of individual flood protection measures. Finally all costs and benefits (avoided risk) are combined to enable the evaluation of flood protection strategies. Every scenario for which benefits outweigh costs potentially adds to welfare. The scenario with the highest contribution per Euro invested should ideally be realised first. The extended cost-benefit analysis is complemented by uncertainty and sensitivity analyses of the results. The applicability of the overall automatic procedure is demonstrated by the evaluation of inundation hazard, exposure and flood risk for a case study along river Ourthe in the Meuse basin (Belgium). For validation purpose, recent flood events are first simulated and a base scenario is considered. Next, the effectiveness of a number of flood protection measures is evaluated. [less ▲]

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See detailTargeted proteomics of nascent RNP particles: A role for DBC1 and ZNF326 in linking mRNA splicing to RNAPII
Close, Pierre ULg; East, P; Svejstrup, J. Q.

Poster (2009, June 12)

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See detailMethylmercury in vitro exposure of harbor seal (Phoca vitulina) lymphocytes: a multidisciplinary approach
Dupont, Aurélie ULg; Siebert, Ursula; Rosenberger, Tanja et al

Poster (2009, June 08)

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See detailDISLOCATIONS AS DEVELOPMENTAL MARKERS IN THE FRENCH LANGUAGE : DEVELOPMENTAL AND PATHOLOGICAL STUDIES
Maillart, Christelle ULg; Parisse, Christophe; Gay-Perret, Nathalie

Poster (2009, June 06)

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See detailChildren with specific language impairment are impaired on implicit higher-order sequence learning, but not on implicit spatial context learning.
Gabriel, Audrey ULg; Schmitz, Xavier; Maillart, Christelle ULg et al

Poster (2009, June 05)

In a recent review of the SLI literature it has been suggested that low language and grammatical abilities would be directly associated with poor learning abilities of nonverbal sequences (Ullman ... [more ▼]

In a recent review of the SLI literature it has been suggested that low language and grammatical abilities would be directly associated with poor learning abilities of nonverbal sequences (Ullman & Pierpont, 2005; Tomblin et al., 2007). Therefore, one could hypothesize that a general purpose sequential pattern tracker could determine some aspects of language and grammar learning. In the present study, 15 children with SLI and 15 matched control children were compared on two implicit learning tasks: an alternating serial response time task in which sequential dependencies exist across non-adjacent elements, and a spatial context learning task in which the global configuration of a display cues the location of a searched target (Chun & Jiang, 1998). We predict that children with SLI will show impaired sequence learning and normal spatial context learning. By confirming the presence of a specific deficit in sequential learning processes, the present study should contribute to better understand the language abilities, and in particular the grammatical difficulties, of individuals with specific language impairment. [less ▲]

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See detailOxylipin profiles of Solanum esculentum and Solanum pennellii under salt stress conditions
Ghars, Mohamed Ali ULg; Frettinger, P.; Ghanem, M. E. et al

Poster (2009, June 05)

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See detailEffects of time of day on age-related differences in cognitive tests.
Schmitz, Xavier ULg; Willems, Sylvie ULg; Meulemans, Thierry ULg

Poster (2009, June 03)

Previous studies have shown a shift in the circadian rhythm – and more particularly in the optimal time of day (OTD) – across the adult life span (May et al., 1993). The aim of this study was to ... [more ▼]

Previous studies have shown a shift in the circadian rhythm – and more particularly in the optimal time of day (OTD) – across the adult life span (May et al., 1993). The aim of this study was to investigate the relationship between cognitive efficiency and OTD in 113 healthy old adults (Age: M = 69, SD = 6.1, Range = 60-80) and 175 younger adults (M = 40.8, SD = 12.9, Range = 20-59). Participants performed a large battery of cognitive tests that assessed episodic memory, working memory, executive and attentional functions. Results on the MEQ (Morningness-Eveningness Questionnaire; Horne & Östberg, 1976) confirmed the age-related shift toward a self-reported morning preference in older adults. Second, the categorization of participants according to their MEQ scores and the time of testing revealed that the OTD has a greater impact upon cognitive performance in older than in younger adults. Third, the age-related OTD impact was more striking in working memory (Brown-Peterson and Pasat) and episodic memory tasks (Buschke) than in other aspects of the cognitive functioning. In conclusion, older participants tested during their peak circadian periods tend to show greater performance on memory tasks that require careful or strategic processing relative to older participants who are tested at off-peak times of day. Taken together, these findings indicate that care must be taken when investigators are considering the effects of age on effortful memory tasks, which are particularly modulated by OTD in older adults. [less ▲]

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See detailMental health and emotions in couples with an alcoholic member
Dethier, Marie ULg; Counerotte, Christelle; Blairy, Sylvie ULg

Poster (2009, June 03)

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See detailA theoretically motivated approach of receptive language assessment based on an interactive spreading activation account of language processing
Martinez Perez, Trecy ULg; Majerus, Steve ULg; Delvenne, Marie-Anne ULg et al

Poster (2009, June 03)

In French language, existing tests do not provide a sensitive assessment of auditory comprehension impairments in aphasic patients. These tests don’t detect slight deficits because their a limited number ... [more ▼]

In French language, existing tests do not provide a sensitive assessment of auditory comprehension impairments in aphasic patients. These tests don’t detect slight deficits because their a limited number of tasks and items. Our aim was to construct a series of more sensible tasks to assess auditory perception. Our battery consists on of phonological, lexical, semantic and verbal short-term memory tasks with a high number of items for each test. The computerization of tasks allows to measure correct answers and time latency and allows a standardized assessment. Our poster will focus on our assessment tasks of auditory comprehension, performances pattern of our aphasic patient and underlying theoretical models. [less ▲]

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See detailPilot scale biotransformation of vegetal oil into natural green note flavor using sugar beet leaves as sources of hydroperoxide lyase
Gigot, Cédric ULg; Ongena, Marc ULg; Fauconnier, Marie-Laure ULg et al

Poster (2009, June 02)

Natural green note aromas (GLVs) are highly attractive flavors commonly used in the food industry. These are produced in extremely low levels upon physiological stress in plant organs of any sort. This ... [more ▼]

Natural green note aromas (GLVs) are highly attractive flavors commonly used in the food industry. These are produced in extremely low levels upon physiological stress in plant organs of any sort. This weak sporadic presence entails a very expensive extraction step to obtain pure GLVs. Therefore catalytic biotransformations of fatty acid sources, the initial substrate for GLVs, have been developed. Enzymatic defense pathways and particularly the LOX pathway produce the major part of GLVs. Unlike GLV molecules that are emitted in the atmosphere, the enzymes are extractible from the plant material. Thus, a combination of plant enzyme extracts and substrate preparations provides all the ingredients for GLV production. Besides, sugar beet leaves present high levels of hydroperoxide lyase among plant sources and are available in large amounts during three months. In this enzymatic pathway, fatty acids are successively transformed by lipase, lipoxygenase and hydroperoxide lyase into aldehydes and alcohols, final compounds of GLVs pathway. Limiting and problematic steps occur with the action of hydroperoxide lyase, when enzymatic catalysis is followed by an enzyme destabilization. Alternative substrates bind irreversibly to the heme group of the enzyme and end the reaction. This poster briefly describes the development of a complete bioprocess for natural GLV production, from hydrolysis to purification. A high level of biotransformation could be achieved using optimum experimental conditions and a cheap source of plant materials. [less ▲]

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See detailRelative serum protein quantification based upon ICPL and 2D-LC-MS identifies potential frailty biomarkers in elderly patients
Turtoi, Andrei ULg; Mazzucchelli, Gabriel ULg; Dobson, Rowan ULg et al

Poster (2009, June 01)

This study shows the ability of the ICPL and nano-HPLC-MS/MS to perform relative quantification and identification of serum protein biomarkers. Frailty is a geriatric syndrome that is commonly associated ... [more ▼]

This study shows the ability of the ICPL and nano-HPLC-MS/MS to perform relative quantification and identification of serum protein biomarkers. Frailty is a geriatric syndrome that is commonly associated with the decline in multisystemic reserve, cognition and sensory capabilities. It is negatively influencing the outcome of a disease prolonging the patient’s recovery. The discrepancy between the actual and the biological age brings the uncertainty of predicting frailty in a given individual. This study is addressing the problem of finding suitable biomarkers that bear the ability to objectively predict frailty in elderly patients. It furthermore provides a robust method for reliable relative quantification of serumproteins. Serum samples used in this study were divided into six groups regarding the patient’s disease (hip-fracture, infection and cardiac decompensation) and frailty status (frail or robust). The individual sera were pooled and a volume of 20 µL was depleted of high abundantproteins. After labeling with ICPL (isotope coded protein label), serum proteins were fractionated according to their respective pI (0-3, 4-7 and 8-12). The samples were further subjected to tryptic digestion followed by the treatment with the Glu-C enzyme. The peptides were analyzed on the 2D-nano-HPLC system (Ulimate 3000®) using four different concentrations of salt injections (45, 75, 150 and 500 mM ammonium acetate). The HPLC system was connected on-line with the electrospray ion-trap mass spectrometer Esquire HCT ultra®. The relative protein quantification using ICPL and mass spectrometry allowed for comparison of six patient groups with respect to a standard sample. The latter represented a group of healthy old subjects. This technique allowed for the detection of approx. 200 proteins, whereas about 50 % of those contained the ICPL label and could therefore be quantified. The identified proteins covered 3 – 4 orders of magnitude ofprotein concentration in human serum. Several proteins displayed a significant modulation allowing for some preliminary conclusions to be drawn. At this point it can be stated that significantly elevated levels of C-reactive protein (factor 12) and alpha-1-antichimotrypsin (f. 4) proved to be potentially good indicators of frailty. Increased concentrations of alpha-1-microglobulin (f. 4) and alpha-2HS-glycoprotein (f. 2) have been found in the robust patients, whereas no significant concentration alteration could be detected in the frail groups. These results refer to the acute phase response since the samples were collected immediately after patient hospitalization. Current investigations addressing the later sampling times should shed more light on the suitability of these markers to predict frailty in elderly patients. At this stage it is obvious that although several markers are found to be in common for all the frail or robust patients, the disease status additionally complicates the biomarker signature. Therefore a more individualized approach should also be considered, where depending on the age and clinical findings a more defined group of markers should be selected to address the problem of frailty. [less ▲]

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See detailFuture CCD and CSH variations: Deep-sea impact of ocean acidification
Munhoven, Guy ULg

Poster (2009, June)

The evolutions of atmospheric CO2 partial pressure (pCO2) and of the carbonate compensation depth and the calcite and aragonite saturation horizons (CSH and ASH, respectively) have been studied with the ... [more ▼]

The evolutions of atmospheric CO2 partial pressure (pCO2) and of the carbonate compensation depth and the calcite and aragonite saturation horizons (CSH and ASH, respectively) have been studied with the coupled oceansediment model MBM-MEDUSA [1], over the next 50,000 years. MBM-MEDUSA includes a full description of sedimentary exchange processes, taking into account chemical carbonate erosion in a consistent way. The adopted emission scenarios were based upon logistic functions [2], considering total emissions of 500, 1000, 2000 and 4240 GtC); the adopted stabilisation scenarios were the S350, S450, S550, S650 and S750 from the IPCC [3]. While the evolutions of atmospheric pCO2 and pH have got a great deal of attention so far (e.g., [4, 5]), only a few studies have considered the saturation horizons [5, 6], and, to our best knowledge, this is the first study also focusing on compensation depth variations. Simulation experiments were started with a 50,000 year spin-up to 1750 A.D. (at steady state). This state was characterised by an atmospheric pCO2 of 277 ppm, a CSH depth of 3350 m and a CCD of 4300 m (in the Indo-Pacific, which can be considered the most representative reservoir for the global ocean). In all experiments, we found that CCD variations were considerably greater than CSH variations. The 500 GtC emission scenario yielded CSH and CCD maximum shoalings of 450 and 800 m, respectively, in the year 3400 A.D. about; with the 4240 GtC emission scenario, both CSH and CCD became shallower than 500 m in 2650 A.D. With the highly optimistic S350 stabilisation scenario, CSH and CCD become even shallower than with the 500 GtC emission scenario (650 m and 1000 m shoaling, respectively), although in the year 5000 A.D. only. For the close-to-CO2-doubling scenario S550, CSH and CCD shoaled by about 1950 and 2450 m (to depths of 1400 and 1900 m, respectively). As a result, most of the sea-floor environment bathed in water that was highly corrosive to carbonate material. In the S650 and S750 scenarios experiments, the CCD becomes shallower than 500 m, leaving little space for benthic carbonate producers to survive. [1] Munhoven (2007) Deep-Sea Res. II 54, 722-746. [2] Bacastow and Dewey (1996) Energy Convers. Mgmt. 37, 1079-1086. [3] IPCC (1994) Climate Change 1994, Cambridge University Press. [4] Caldeira and Wickett (2003) Nature 425, 325-325. [5] Orr et al. (2005) Nature 437, 681-686. [6] Cao and Caldeira (2008) Geophys. Res. Lett. 35, L19609. [less ▲]

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See detailShort-term temperature impacts on soil respiration.
Buysse, Pauline ULg; Goffin, Stéphanie ULg; Carnol, Monique ULg et al

Poster (2009, June)

Despite considerable recent work on soil heterotrophic respiration, a mechanistic understanding of this process is still missing. Temperature is one of the most important driving factors. It can influence ... [more ▼]

Despite considerable recent work on soil heterotrophic respiration, a mechanistic understanding of this process is still missing. Temperature is one of the most important driving factors. It can influence the mechanism through multiple ways, whose importance may vary with time. An incubation experiment is set up to study short-term temperature influences on soil microbial respiration and its evolution through time. Soil samples are taken in spring from the surface layer (0-25cm) of a bare agricultural loamy soil situated in Lonzée in Belgium (Hesbaye region) and are homogenized before being placed into incubators at three different temperatures, namely 5, 15 and 25°C. Temperature is regulated by Peltier systems that warm up or cool down a sand bath containing jars with soil samples. Once a week, incubation temperatures are increased and decreased by 5°C-steps, starting from each incubator temperature, to achieve a one-day temperature cycle between 5 and 35°C. CO2 flux measurements are performed at each temperature step by a closed dynamic chamber system, after the temperature has stabilized in the samples. Microbial biomass (C and N) is determined four times during the temperature cycle by the fumigation-extraction technique and soil labile carbon is measured at the beginning of each cycle by the hot-water extraction method. Moisture levels in soil samples are regularly checked and adjusted to keep optimal soil moisture content. Between CO2 flux measurements, jars are left open to ensure that anaerobic conditions do not occur. Further investigations could include an assessment of the importance of substrate availability and depletion on microbial activity, and a model development related to the results provided by this experiment. [less ▲]

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See detailTheoretical Study of Transformation Mechanism for the Corundum-to-Rh2O3(II) Transition in Al2O3
Xu, Bin ULg; Dong, Jianjun; Stokes, Harold et al

Poster (2009, June)

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See detailFirst-Principles Study of Phase Transitions in Silicon Nitride at High Pressure
Xu, Bin ULg; Dong, Jianjun; Shebanova, Olga et al

Poster (2009, June)

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See detailMaturation of toxins in the venom duct of conustextile
Dobson, Rowan ULg; Collodoro, Mike; Gilles, Nicolas et al

Poster (2009, June)

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See detailHigh incidence of invasive group B streptococcal infections in uninfected infants born to HIV-1 mothers
Epalza, C.; Goetghebuer, T.; Hainaut, M. et al

Poster (2009, June)

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See detailFirst-Principles Study of the Mechanism for B4-to-B1 Phase Transformation in AlN
Xu, Bin ULg; Dong, Jianjun; Stokes, Harold et al

Poster (2009, June)

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See detailHow good are we at extracting personal information from voices?
Dehon, Hedwige ULg; Lambert, Florence

Poster (2009, June)

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See detailSleep in the vegetative and minimally conscious states
Cologan, Victor ULg; Schabus, Manuel; Maquet, Pierre ULg et al

Poster (2009, June)

Résultats préliminaires de l'étude du sommeil chez les patients cérébrolésés en état de conscience altéré.

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See detailQuantifying hand cross contamination in food.
Rodrigues, Ana; Dure, Rémi ULg; Delhalle, Laurent ULg et al

Poster (2009, June)

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See detailLa validité de construit des épreuves physiques qui mesurent l’aptitude physique générale sportive des candidats pour une formation en sport au Maroc et en Algérie
Alem, Jaouad; Dadouchi; Kerfes, Nabil et al

Poster (2009, June)

A l’instar de certains chercheurs en sciences de l’éducation qui ont tenté de démontrer l’existence d’un facteur unique d’intelligence générale G, certains kinésiologues ont, eux aussi, longtemps cru en ... [more ▼]

A l’instar de certains chercheurs en sciences de l’éducation qui ont tenté de démontrer l’existence d’un facteur unique d’intelligence générale G, certains kinésiologues ont, eux aussi, longtemps cru en l’existence d’un facteur unique d’aptitude physique générale sportive (Thomas, 1989). Cette recherche analyse la validité de construit des épreuves physiques censées mesurer l’aptitude physique générale des candidats pour une formation supérieure en sport au Maroc (7 épreuves) et en Algérie (4 épreuves). La base de données est composée de 990 candidats masculins du Maroc et 491 de l’Algérie, âgés en moyenne de 20 ans. Les analyses factorielles en composantes principales avec rotation varimax des performances à ces épreuves aussi bien selon le genre des candidats que selon leur spécialité sportive révèlent systématiquement une solution factorielle en deux composantes qui se distinguent selon la durée du travail pour produire de l’énergie et qui prédisent plus de 50% de la variance du construit mesuré. La 1ière composante correspond à la puissance musculaire phosphagénique ou encore à la capacité de produire en moins de sept secondes du phosphate déjà présent dans les muscles, elle est définie par les autres épreuves physiques. La 2ième composante correspond à la puissance musculaire glycolytique ou encore à la capacité de produire du lactate en plus de 12 secondes, elle est définie par la course de vitesse et la course de résistance. Nos analyses n’ont pas démontré la validité de construit de 7 ou 4 dimensions différentes d’aptitude physique sportive mais plutôt l’existence de deux composantes différentes de la puissance musculaire. [less ▲]

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See detailThe influence of encoding style on false memories
Dehon, Hedwige ULg; Laroi, Frank ULg; Van der Linden, Martial

Poster (2009, June)

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See detailAnalyse comparée de la formation des éducateurs sportifs en Algérie et en Communauté française de Belgique
Kerfes, Nabil; Boudaoud, Abdelyamine; Alem, Jaouad et al

Poster (2009, June)

Toute formation supérieure a ses principes et ses particularités visant à développer des compétences en relation avec les finalités professionnelles disponibles. La formation des éducateurs sportifs est l ... [more ▼]

Toute formation supérieure a ses principes et ses particularités visant à développer des compétences en relation avec les finalités professionnelles disponibles. La formation des éducateurs sportifs est l'une des préoccupation majeurs de toutes les sociétés cherchant le progrès et le développement, il existe de nombreuses raisons pour lesquelles les nouveaux étudiants choisissent leur avenir universitaire ou professionnel, ils abordent l'enseignement supérieur avec des dispositions diverses à l'égard du contenu de la formation et des professions sur lesquelles elle débouche. Ce travail se situe dans le champ de l’éducation comparée. Il propose une lecture compréhensive de deux systèmes de formation dans un esprit d’ouverture et d’élargissement des connaissances. En nous inspirant de deux études effectuées dans le domaine de la formation des éducateurs physiques dans des contextes culturels très différents (Groupe de recherche de MJS, 1983, pour l’Algérie – Groupe de recherche interuniversitaire, 2003, pour la Belgique francophone). L’objectif de cette recherche a dès lors consisté à déterminer les motifs qui incitent les étudiants à s'inscrirent aux études de diverses formations sportives, qu’ils soient universitaires ou non. Notre recherche s’est basée, d’une part, sur l’analyse des textes officiels relatifs à l’organisation des études supérieures dans le domaine sportif et, d’autre part, sur des données collectées auprès des acteurs impliqués dans quatre institutions de formation, deux de la région d’Alger et deux de la région liégeoise. Il convient de retenir que, dans chaque contexte culturel, une institution universitaire et une non universitaire ont été analysées. Nos résultats portent ainsi sur un échantillon total de 290 sujets (40 membres des staffs pédagogiques, 108 étudiants et 142 diplômés). Les formateurs ont été interviewés tandis que les sujets des deux autres groupes ont répondu à des questionnaires. La version arabe de chaque instrument a été traduite à partir des outils en français. Un expert en a assuré le contrôle de validité. Dans cet article, nous porterons notre attention sur l’analyse des réponses fournies par les trois types d’acteurs à deux questions fermées consistant à identifier le degré d’importance accordé par les sujets à des motifs d'inscription aux études en éducation physique et sportive, par l’intermédiaire d’échelles de Lickert à quatre niveaux. Les réponses ont été encodées dans une base de données informatique et traitées au moyen du logiciel Statistica (Stat Soft, 2006). Aucune différence significative n’est enregistrée dans la comparaison des réponses des sujets interrogés. Nous constatons toutefois que, d'une part, l'amour du sport et la volonté de pratiquer du sport sont parmi les plus importants des motifs de suivre cette formation, et d'autre part, dans les deux institutions belges, une importance plus grande est donnée à l'entraînement sportif, le contexte culturel ne semble pas non plus beaucoup influencer les avis des sujets interrogés. [less ▲]

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See detailFading of Modern Prussian Blue Pigments : Preliminary Study
Samain, Louise ULg; Sougrati, Moulay T.; Hatert, Frédéric ULg et al

Poster (2009, June)

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See detailMarginal bone resorption and marginal bone level around implants in the posterior mandible: A 4-year retrospective study.
LAMBERT, France ULg; Geron, Caroline; LECLOUX, Geoffrey ULg et al

Poster (2009, June)

Long-term bone remodelling of implant placed in the posterior mandibule: a radiological study. France Lambert, Kim Vincent, Caroline Geron, Geoffrey Lecloux, Eric Rompen. Purpose: The aim of this study ... [more ▼]

Long-term bone remodelling of implant placed in the posterior mandibule: a radiological study. France Lambert, Kim Vincent, Caroline Geron, Geoffrey Lecloux, Eric Rompen. Purpose: The aim of this study was to analyse direct and long-term (4 years) marginal bone remodelling of various implant systems placed in the posterior mandibule with a single stage approach. Materials and methods: 50 partially edentulous patients received a total of 114 implants in the posterior mandibule (TE implant, Straumann®, Switzerland; Replace® Select Straight, Nobel Biocare, Sweden; Branemark System® MKIV, Nobel Biocare, Sweden). All implants were non-submerged, and loaded 8 to 12 weeks post surgery. X-rays were taken at baseline, 6 weeks, after loading and at long-term. Using a image processing program (Image J), bone losses were measured at each time point. Bone levels were also recorded using the first thread as reference point. Results: The mean bone loss reached 0.506±0.498 mm at 6 weeks, 0.798±0.599 after loading and 1.037±0.799 after 4 years. Bone losses were significatively higher on smokers and on patients displaying signs of bruxism. No statistical difference was found between the different implant types. Conclusion: 50% of the bone loss had already occurred within the 6 weeks post surgery with all implant types. Higher bone losses were often associated to risk factors such as tabacco addiction and bruxism. [less ▲]

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See detailEvaluation of the dynamic adsorption of gas on active carbon beds using in situ X-ray µ-tomography coupled with 3D image analysis
Almazan, Maria del Carmen; Léonard, Angélique ULg; Lodewyckx, Peter et al

Poster (2009, June)

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See detailEvidence for distinct roles for basal ganglia and SMA in automatic and unconscious inhibition of voluntary actions
D'Ostilio, Kevin ULg; Garraux, Gaëtan ULg

Poster (2009, June)

Introduction: Although previous research highlighted the importance of automatic and unconscious inhibition in motor control, the neural correlates of such processes remain unclear. Basal ganglia ... [more ▼]

Introduction: Although previous research highlighted the importance of automatic and unconscious inhibition in motor control, the neural correlates of such processes remain unclear. Basal ganglia dysfunctions have long been associated with impairment in automatic motor control. In addition, Sumner & al. (2007) suggested a key role of the medial frontal cortex by administrating a masked priming task (e.g., Eimer & Schlaghecken 2003) to a patient with a small lesion restricted to the supplementary motor area (SMA)., Here, we used fMRI in normal subjects to better delineate the respective roles of SMA and basal ganglia in automatic and unconscious motor inhibition. Methods: We used event-related BOLD fMRI at 3T to record brain activity in 26 healthy volunteers (22 ± 2 years) as they performed the subliminal masked priming task. In this visuomotor task, participants are asked to make speeded button presses with the left or right hand following leftward or rightward pointing arrows, which are preceded by masked prime arrows. Here, two experimental variables were manipulated: the interval between the mask and the target (SOA: 0,100,150,200 or 250 ms) and the prime/target direction (compatible or incompatible). Imaging data processing and analysis were performed using SPM8b. Results: using Repeated Measures ANOVA of behavioral data (global interaction SOA*compatibility, p<0.0000001), we replicated the masked priming effects showing faster reaction times (i.e., motor response facilitation) in compatible than incompatible trials at 0-SOA (positive compatibility effect: diff = 21 ms, linear contrast : p<0.0000001) and the reverse (negative compatibility effect) at 100 (diff = -12 ms, p= 0.01) and 150-SOA (diff= -12 ms, p= 0.008) suggesting motor response inhibition. At 200 & 250 SOA, we no longer found significant compatibility effects (p>0.05) By applying a similar statistical model to imaging data, we observed a stronger activity in the in several regions, the SMA (p<0.001, uncorrected), caudate (p=0.002, uncorrected) and thalamus (p<0.001, uncorrected) showing stronger activity in compatible than incompatible trials at 100 and 150-SOA, as compared with 0-SOA. Moreover, the differential activity in the SMA was correlated with the negative compatibility effect (p= 0.01). When testing for a main effect of SOAs we didn’t find a differential activation of the SMA, but a stronger deactivation of the caudate (p=0.009, uncorrected) and the thalamus (p=0.007, uncorrected) at 100-150 SOA (inhibition conditions) compared to 0-SOA (facilitation condition). In a prime identification task administered after the fMRI experiment, subjects’ performance was at chance levels for primes displayed for 17 ms as in the main study, suggesting that the prime was not consciously perceived. Conclusions: These new findings suggest that automatic and unconscious inhibition of an activated motor response is mediated by the basal ganglia whereas medial frontal regions seem to be more implicated in the control of response conflict related to inhibition. [less ▲]

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See detailS'auto-former aux TIC
Henry, Julie ULg; Denis, Brigitte ULg; Vandeput, Etienne ULg

Poster (2009, June)

Poster présentant deux dispositifs de formation visant la maitrise des TIC et la méthodologie (didactique des TIC) qui les sous-tendent.

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See detailIdentification of biomarkers to estrogen exposure using MCF-7/BOS cell line exposed to 17β-estradiol and phytoestrogens
Collodoro, Mike ULg; Bertrand, Virginie ULg; Lemaire, Pascale ULg et al

Poster (2009, June)

Use of an estrogen responsive cell line and proteomic for biomarker discovery and the screening of xenoestrogen

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See detailTxXIIIA, an atypical homodimeric conotoxin found in the Conus textilevenom
Quinton, Loïc ULg; Gilles, Nicolas; De Pauw, Edwin ULg

Poster (2009, June)

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See detailStudy of the potential regulation of Sprouty1, an angiogenesis inhibitor, by miR-21
Sabatel, Céline; Malvaux, Ludovic; Cornet, Anne et al

Poster (2009, May 29)

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See detailUniversal solid support synthesis of modified oligonucleotides labeled by click chemistry for PET studies
Flagothier, Jessica ULg; Mercier, Frederic; Kaisin, Geoffroy ULg et al

Poster (2009, May 29)

Introduction: Positron emission tomography (PET) is a high-resolution, sensitive, molecular and functional imaging technique that permits repeated, non invasive assessment and quantification of specific ... [more ▼]

Introduction: Positron emission tomography (PET) is a high-resolution, sensitive, molecular and functional imaging technique that permits repeated, non invasive assessment and quantification of specific biological and pharmacological processes in humans[1]. In regard to its physical and nuclear characteristics, fluorine-18 appears often as the radionuclide of choice for the preparation of short-lived positron-emitter radiotracers[2]. F-18 labelling reaction of biomolecules such as peptides[3], oligosaccharides, and oligonucleotides[4] (ONs) requires very mild reaction conditions. The method of choice for a highly efficient fluorine-18-labelling of ONs is today the conjugation of a prosthetic group, carrying the radioisotope, with a reactive function of the ONs. Methods: For the ligation reaction of the prosthetic group with the ONs, we selected click reaction and more particularly the CuI catalyzed formation of 1,2,3-triazole using Huisgen 1,3-dipolar cycloaddition of terminal alkynes with azides. This reaction is highly regioselective leading to 1,4-disubstituted 1,2,3-triazoles and can be performed in different solvents with very high yield[5-7]. Conjugations with ONs are usually performed at 3’-ends using a well chosen linker in order to limit degradation by exonucleases[8]. Here we report the synthesis of an alkyne-bearing linker which can be attached at 3’-ends to any sequence of ONs. Results: The linker was prepared in two steps by reaction of commercially available (R)-(+)--hydroxy--butyrolactone with propargylamine followed by protection of the primary hydroxyl with the 4,4’-dimethoxytrityl group[9]. The second step is the reaction with succinic anhydride to obtain a carboxylic function which can be attached to the Amino-SynBase CPG. The resin load was 80 µmol/g. Conclusions: We have prepared a new universal linker which allows introducing an alkyne function at the 3’-end of ONs. This alkyne modified ONs can then react under click conditions with an azide function of a prosthetic group carrying the fluorine radioisotope. As prosthetic group, we selected the 1-azido-4-(3-[18F]fluoropropoxy)benzene which is fully automated produce in our lab[10]. The further results of radiosynthesis of this prosthetic group and the results of click reactions will be presented. Acknowledgement: The authors wish to thank Teller N. from Eurogentec (Seraing, Belgium) for oligonucleotide synthesis. The authors wish to acknowledge the financial support from the Oligopet Projet of the Walloon Region. [less ▲]

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See detailStudy of the role of microRNAs in angiogenesis
Malvaux, Ludovic; Pendeville, Hélène; Sabatel, Céline et al

Poster (2009, May 29)

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See detailFinding Mir able to regulate angiogenesis
Pendeville, Helene; Nivelles, Olivier ULg; Malvaux, L. et al

Poster (2009, May 29)

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See detailEffects of compression on human subchondral osteoblast metabolism
Kesteloot, Frédéric ULg; Gabay, Odile; Msika, Philippe et al

Poster (2009, May 24)

Introduction. Recent data showed that subchondral bone plays an important role in osteoarthritis (OA). Metabolic and morphologic modifications in this tissue contribute to the degradation of the ... [more ▼]

Introduction. Recent data showed that subchondral bone plays an important role in osteoarthritis (OA). Metabolic and morphologic modifications in this tissue contribute to the degradation of the overlaying cartilage. It was suggested that abnormal mechanical pressure exerted onto the articulation was responsible to these changes. Here, we evaluated the effects of compression on osteoblasts from subchondral bone. Method. Osteoblasts were isolated from sclerotic (SC) or non-sclerotic (NSC) areas of human OA subchondral bone. After 28 days, osteoblasts were surrounded by their matrix. This osteoblasts-containing membrane was then placed onto a Biopress Flexercell plate and submitted to a 4h 1.67 MPa compression (1 Hz). Expression of IL-6, IL-8, COX-2, VEGF, IGF-1, OPG and RANKL was evaluated by RT-PCR. IL-6, IL-8 and PGE2 were quantified by ELISA. Results. Basal IL-6, VEGF, COX-2, IGF-1 and RANKL mRNA levels were significantly increased in SC osteoblasts as compared to NSC. By contrast, SC osteoblasts expressed less OPG than those from NSC areas. Compressions induced the expression of genes coding for IL-6, IL-8, COX-2, IGF-1, VEGF and RANKL but decreased the expression of OPG in NSC osteoblasts (p<0.01). Interestingly, compressed NSC osteoblasts expressed similar levels of these genes than SC osteoblasts. Conclusions. We show that our model of compression can induce in NSC osteoblasts a phenotype similar to this observed in sclerotic areas. Moreover, SC osteoblasts are less sensitive to mechanical stimuli than NSC osteoblasts. These results clarify the role of compression in the pathogenesis of subchondral bone sclerosis and allow new perspectives of research in this field. [less ▲]

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See detailFollow-up of COLL2-1, COLL2-1NO2 and myeloperoxydase in dogs after transection of the cruciate ligament of the knee
Kesteloot, Frédéric ULg; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne et al

Poster (2009, May 23)

Purpose: To determine the profile of Coll2-1, Coll2-1NO2 and myeloperoxydase (MPO) serum concentrations in experimental knee OA induced in the dog by transection of the anterior cruciate ligament. Methods ... [more ▼]

Purpose: To determine the profile of Coll2-1, Coll2-1NO2 and myeloperoxydase (MPO) serum concentrations in experimental knee OA induced in the dog by transection of the anterior cruciate ligament. Methods: Surgical transection of the ACL of the right knee was performed on 16 adult crossbred dogs. The dogs were sacrificed 8 weeks after the surgical procedure. Coll2-1, Coll2-1NO2 and MPO were measured by specific immunoassays in 16 dogs at baseline and every 2 weeks during the 8 weeks. The results were expressed as median (range). Results: Immunostainings with D3 and D37, the antiserum recognizing Coll2-1 and Coll2-1NO2, respectively, labelled extracellular matrix in the superficial layer of fibrillated cartilage. After the transection of the ACL, the concentration of 3 biomarkers increased significantly (Friedman test: p<0.001). The concentrations of Coll2-1 and MPO were significantly increased at week 2 compared to baseline [Coll2-1 baseline: 281.57 (131.02-384.67) nM vs Coll2-1 week 2: 345.52 (181.15-589.25) nM (p<0.01) and MPO baseline: 5.16 (<0.4-14.7) ng/ml vs MPO week 2: 14.54 (3.28-31.50) ng/ml (p<0.001)] and remained stable until week 8 [Coll2-1 week 8:318.89 (117.95-492.28) nM and MPO week 8: 11.55 (2.87-42.94) ng/ml]. The Coll2-1NO2 concentration increased significantly at weeks 6 and 8 compared to baseline [Coll2-1NO2 baseline: 0.54 (0.29-1.48) nM vs Coll2-1NO2 week 6: 0.64 (0.40-1.9) nM (p<0.001) vs week 8: 0.61 (0.37-1.79) nM]. Conclusions: These findings suggest that Coll2-1 is a relevant marker for the detection of early structural changes in OA dogs. Interestingly, MPO and Coll2-1NO2 are increased in OA dogs indicating that an oxidative stress occurs in this OA model. [less ▲]

Detailed reference viewed: 56 (8 ULg)
See detailBacillus-based biocontrol of Fusarium disease on tomato cultures in Burundi
Nihorimbere, Venant; Ongena, Marc ULg; Cawoy, Hélène ULg et al

Poster (2009, May 19)

Detailed reference viewed: 27 (5 ULg)
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See detailPreparation of living polymer microspheres by dispersion atom transfer radical polymerization in scCO2 using fluorinated macroligands
Grignard, Bruno ULg; Calberg, Cédric ULg; Jérôme, Christine ULg et al

Poster (2009, May 19)

Due to an increasing need for polymers with well-defined architecture (diblock-, graft-, star-shaped copolymers), molecular weight and/or functional end-groups, the use of controlled radical ... [more ▼]

Due to an increasing need for polymers with well-defined architecture (diblock-, graft-, star-shaped copolymers), molecular weight and/or functional end-groups, the use of controlled radical polymerization (CRP) in scCO2 has started to gain attention. Among all the controlled processes, Atom Transfer Radical Polymerization has emerged as a robust tool for the preparation of polymers with well-defined molecular weight, architecture and chain-end functionality. In a very recent paper, we reported the first efficient dispersion ATRP of methyl methacrylate (MMA) in scCO2 using a fluorinated polymeric ligand that had a dual role, i.e., the complexation of the copper salt and the stabilization of PMMA growing particles. In this contribution, we extended this new system to the dispersion ATRP of styrene, to the synthesis of diblock copolymers beads and the controlled synthesis of hyperbranched copolymers. Finally, because both ATRP and alkyne-azide Huisgen’s 1,3-dipolar cycloaddition relies on the use of a Cu(I) catalyst, synthesis of pyrene end-functionalized polymers by simultaneous dispersion ATRP and click reaction was also investigated in supercritical carbon dioxide. [less ▲]

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See detailEvaluation of two protein extraction protocols for Pichia anomala proteome analysis.
Bajji, Mohammed; Delaplace, Pierre ULg; Mauro, Sergio et al

Poster (2009, May 19)

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of ... [more ▼]

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of action have until now been studied using essentially microbiological and molecular approaches. The study continues now using the proteomic approach and considering the in situ P. anomala/B. cinerea/apple interaction. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the most powerful tools used for proteomic analysis. It combines two sequential separation steps, the first dimension via isoelectric focusing (IEF) and the second one by SDS PAGE. Although recent advances in 2-D PAGE, the extraction of the whole proteome and the removal of interfering contaminants still limit its application. Sample preparation constitutes indeed a critical influential step for IEF which in turn affects 2-D gel quality. The objective of the present work was thus to develop an effective protein extraction protocol designed for 2-D PAGE analysis of the proteome of P. anomala strain Kh6. As a starting point, two contrasting protein extraction protocols were chosen to be evaluated in terms of protein yield and one-dimensional (1-D) SDS PAGE and 2-D PAGE gel patterns. The first protocol uses a urea/thiourea-based lysis buffer whereas the second protocol utilizes a hot SDS-based lysis buffer with an additional precipitation step. The comparison model used consisted of apples treated with strain Kh6 alone (K) and apples first treated with Kh6 and then inoculated with B. cinerea conidia (KB). Growth kinetics of strain Kh6 on wounded apples was determined and found to be not affected by the presence of B. cinerea conidia. Proteins were extracted from yeast pellets collected at both the exponential and stationary phases of strain Kh6 growth on apples. The evaluation of both extraction protocols indicates that more proteins were extracted with the SDS protocol and, according to 1-D assays, higher molecular weight proteins were obtained with the ‘urea/thiourea’ protocol and, regardless of the protocol used, more bands were obtained during the exponential phase. 2-D assays are currently underway and the corresponding results will be presented. [less ▲]

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See detailMONITORING OF THE ENTOMOLOGICAL DIVERSITY IN A PESTICIDE FREE ORCHARD: INVESTIGATION OF THE GEMBLOUX AGRICULTURAL UNIVERSITY CONSERVATORY
Poligui, René Noël ULg; Haubruge, Eric ULg; Francis, Frédéric ULg

Poster (2009, May 19)

In orchards, the fruit production is currently oriented to integrated pest management. In order to develop efficient pest control strategy by using entomophagous beneficial and lowering the application of ... [more ▼]

In orchards, the fruit production is currently oriented to integrated pest management. In order to develop efficient pest control strategy by using entomophagous beneficial and lowering the application of pesticides, sufficient knowledge of entomological populations is needed. Here, a systematic monitoring of insect diversity and abundance in a conservatory orchard of Gembloux was performed. Combining yellow traps and visual observations, 19 pest and 34 beneficial families were identified among the 10766 and 3985 insects caught in yellow traps and visual observations respectively. Calculation of diversity indices allowed us to demonstrate the variability according to fruit tree species and insects observation method. Highest insects diversity was registered in apple, then in cherry and finally in the apple-pear association and plum. Pests and beneficials represented 27% and 39% of the insect collections respectively. Aphids represented from 81% to 95%of pests depending on fruit tree species and observation method. The predominant specie was Brachycaudus helychrysi (Kaltenbach). Aphidophagous guild was largely present and mainly constituted by coccinellids and hoverflies. Harmonia axyridis Pallas and Episyrphus balteatus De Geer were the most abundant. Aphididae was found to be the most common orchard pests with a range of related aphidophagous beneficials. These results highlight the need leading to potential reasoning . [less ▲]

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See detailFunctionalization of aliphatic polyesters by “click chemistry” in supercritical carbon dioxide
Grignard, Bruno ULg; Schmeits, Stephanie ULg; Riva, Raphaël ULg et al

Poster (2009, May 14)

The combination of ring-opening polymerization of lactones and “click” copper-catalyzed Huisgen’s [3+2] cycloaddition is known to be a very efficient strategy for the functionalization of poly(ε ... [more ▼]

The combination of ring-opening polymerization of lactones and “click” copper-catalyzed Huisgen’s [3+2] cycloaddition is known to be a very efficient strategy for the functionalization of poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA). Whenever the “click” reaction occurs in an organic solvent (THF or DMF), at relatively low temperature (35°C) and within short reaction time (2 hours), no significant degradation of polyester chains is detected. This strategy was implemented in previous works to graft alkynes substituted by different functional groups, such as hydroxyl, tertiary amines, acrylates or ammonium salts onto azide-functionalized PCL. Moreover, this approach was previously extended to the synthesis of grafted copolymers, either by the grafting of omega-alkyne-PEO onto azide-functionalized aliphatic PLA or PCL (“grafting onto” technique) either by grafting of an ATRP initiator followed by the polymerization of vinyl monomers, such as styrene (“grafting from” technique). These functionalized aliphatic polyesters are promising materials for the development of new biomedical devices. In this work, novel conditions were implemented for the “click” reaction in order to avoid the use of organic solvents and to limit the amount of catalyst remnants in functionalized aliphatic polyesters. Toward this end, if was found that the functionalization by “click” chemistry can be efficiently carried out in supercritical carbon dioxide rather than in THF or DMF. For that sake, it turned out necessary to synthesize a perfluorinated polyamine in order to solubilize the catalyst in supercritical carbon dioxide. Aliphatic polyesters are not soluble in supercritical carbon dioxide. Nevertheless, even under heterogeneous conditions, the functionalization of aliphatic polyesters by “click” chemistry is quantitative. Interestingly enough, no degradation was observed. Last but not least, the copper catalyst was easily removed by supercritical fluid extraction leading to a very low content of residual copper in the final copolyester. [less ▲]

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See detailMannosylated amphiphilic and degradable PEO-b-PCL copolymers for drug delivery systems: preparation and sugar availability characterizations
Freichels, Hélène ULg; Imberty, Anne; Auezély-Velty, Rachel et al

Poster (2009, May 14)

Over the last decade, polymer micelles and nanoparticles attracted an increasing interest in pharmaceutical research because they can be used as efficient drug delivery systems. In this field, amphiphilic ... [more ▼]

Over the last decade, polymer micelles and nanoparticles attracted an increasing interest in pharmaceutical research because they can be used as efficient drug delivery systems. In this field, amphiphilic copolymers combining poly(ethylene oxide) and aliphatic polyester (such as poly(ε-caprolactone) (PCL) or polylactide (PLA)) are particularly of interest because (i) PEO has unique protein- repellent properties and thus provides a stealth behaviour to the drug carriers and (ii) aliphatic polyesters are biocompatible and biodegradable hydrophobic matrices well-suited for the incorporation of an hydrophobic drug. By end-capping the hydrophilic segment by a targeting moiety so that they may interact with membrane receptors, the biodistribution of polymeric micelles and nanoparticles stabilized with this copolymer can be modulated and can induce specific cellular uptake by receptor-mediated endocytosis. One class of interesting targeting agent is the saccharides, in particular the mannose, because of its specific interaction with mannose receptor, which are found on peripheral and bone marrow macrophages, dendritic cells and sinusoidal liver cells. In this study, the reductive amination reaction is use to attach this targeting agent. After optimisation of the reaction with amino fluorescein, a model amine, mannosylated copolymer of PEO and PCL has been prepared. The surface availability of the saccharide upon the micelles in aqueous phosphate buffer was then assessed by DLS through binding with the protein Concanavalin A (ConA), a known mannose receptor. The interactions between the Bcla lectin and the mannosylated micelles have then been studied by Isothermal Titration Calorimetry (ITC) and the thermodynamic parameters have been obtained. This polymer is particularly useful for the stabilization of PLGA nanoparticles with the goal to target M cells for oral vaccination. [less ▲]

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See detailDispersion nitroxide mediated polymerization of MMA in supercritical carbon dioxide
Grignard, Bruno ULg; Gigmes, Didier; Jérôme, Christine ULg et al

Poster (2009, May 14)

Controlled dispersion Nitroxide Mediated Polymerization (NMP) of methyl methacrylate (MMA) was successfully carried out for the first time in supercritical carbon dioxide (scCO2) in the presence of CO2 ... [more ▼]

Controlled dispersion Nitroxide Mediated Polymerization (NMP) of methyl methacrylate (MMA) was successfully carried out for the first time in supercritical carbon dioxide (scCO2) in the presence of CO2-philic perfluorinated surfactant that was generated “in situ”. The control of the MMA polymerization relies on the strategy developed by Charleux et al. that consists of using a SG1-based alkoxyamine, i.e. the block-builder, in the presence of small amount of styrene. In a first step, CO2 soluble polyheptadecafluorodecylacrylate was prepared in scCO2 using block-builder as an alkoxyamine. In a second step, nitroxide SG1 mediated dispersion polymerization of MMA was conducted at 70°C and 300 bar in the presence of 5 w% of SG1 terminated surfactant compared to the monomer. Different monomer to alkoxyamine molar ratios were investigated in order to target different molecular weights. In each case, the monomer conversion was high (>90 %), the experimental molecular weight was in good agreement with the theoretical value and the polydispersity was narrow (Mw/Mn ~1.2). Moreover, after depressurisation of the cell, PMMA was collected as a free flowing powder consisting of small sized microspheres. [less ▲]

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See detailpH-sensitive micellar systems for controlled drug delivery: synthesis and structural characterization by small-angle neutron scattering
Joset, Arnaud ULg; Jérôme, Christine ULg; Brulet, Annie et al

Poster (2009, May 14)

The aim of the project is the preparation of micellar nanocarriers made of biocompatibles copolymers and their structural analysis by Small Angle Neutron Scattering (SANS). These micelles could be used in ... [more ▼]

The aim of the project is the preparation of micellar nanocarriers made of biocompatibles copolymers and their structural analysis by Small Angle Neutron Scattering (SANS). These micelles could be used in drug delivery applications to fight cancer1. The hydrophobic polycaprolactone (PCL) core is intended to incorporate the drug. The corona of hydrophilic polyethylene oxide (PEO) stabilizes the nanocarriers with respect to the plasma proteins. The pH in the neighborhood of the tumoral cells is lower than in the healthy cells. We incorporated a pH-sensitive sequence of poly(2-vinylpyridine) (P2VP). As a result, these micelles are expected to deliver their drug near the cancerous cells without affecting the healthy cells. When the pH is acidic, the P2VP is protonated and the chains are repulsive. The micellar size is then larger than in basic pH, when the P2VP is precipitated on the PCL core. We prepared PCL65-b-P2VP31 / PCL65-b-PEO114 and PCL32-b-P2VP52 / PCL36-b-PEO114 50:50 mixtures of diblocks copolymers. The resulting mixed micelles are analyzed by SANS. We developed a theoretical model with a spherical water-free PCL core. The PEO corona is described as consisting of gaussian chains with a thickness estimated as twice the chain gyration radius, Rg. We propose two alternatives for handling the P2VP zone. The P2VP molecules are either assumed to be Gaussian chains or they fill a shell of thickness L with possible water penetration.The fitting of the models to the experimental scattering cross sections leads to important structural parameters like the aggregation number, the core radius, the gyration radius and the thickness of the P2VP shell. [less ▲]

Detailed reference viewed: 90 (16 ULg)