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See detailScreening Elisa method to assess in vitro efficacy of new agents based on Lactoperoxydase system against phytopathogens
Bafort, Françoise ULg; Lepoivre, Philippe ULg; Jijakli, Haissam ULg et al

Poster (2011, May 24)

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of ... [more ▼]

The lactoperoxydasesystem (LPS) is a natural biological protection system in human saliva, milk and tears. Lactoperoxydase catalyzes the oxidation of iodide (I-) and thiocyanate (SCN-) in presence of hydrogen peroxide in hypoiodite (OI-) and hypothiocyanite (OSCN-) ions. Both ions have inhibitory action against pathogenic bacteria, fungi and viruses. Until now, the ions OI- and OSCN- applied separately from the LPS were not tested against plant pathogens. Seventeen KI/KSCN/H2O2 ratios with 3 dilutions for each one were tested against Botrytiscinerea. Results showed that the ions OI- and OSCN- gives a better % of inhibition with: -high concentration of KI+KSCN, -a ratio of KI/KSCN of 4.5 and -a ratioof (KI+KSCN)/H2O2 near 1. Increased dilution combined with lower KI+KSCN concentration reduced the efficacy of the ions. From the screening against B.cinerea, 4 ratios of KI+KSCN were selected and tested against 6 other phytopathogens. Results showed that the OI- and OSCN- ions give 87 and 100% inhibition against Penicillium expansum and Verticillium dahlia respectively. The inhibitory activity of the ions solution was ranged between 70 and 79% regarding Fusarium avenaceum, Phytophthora infestans and Colletotrichum lindemuthanium. The ions OI- and OSCN- showed an insufficient inhibitory activity against Septoria tritici. The screening method highlighted that high KI/KSCN ratios and low dilution were more efficient against phytopathogens. The efficient ratios will be further evaluated in vivo. [less ▲]

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See detailVolatile organic compounds of the roots of barley and their role in the rhizosphere
Fiers, Marie ULg; Barsics, Fanny ULg; Camerman, Marc ULg et al

Poster (2011, May 24)

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates ... [more ▼]

Volatile organic compounds emitted by plants are known to intervene with various biotic environmental factors. Up to now, most of the studies have been focused on aerial volatiles and root liquid exudates. Very few researches have been completed concerning belowground volatiles released into the rhizosphere despite their potential capacity to carry information between organisms. The Rhizovol project, started in autumn 2010, involves 5 different units of Gembloux Agro-Bio Tech collectively studying the production of belowground volatiles by barley roots underlying various biotic interactions in the rhizosphere. Some preliminary results of each partner of the project will be presented. To achieve this goal, analytical methods allowing the sampling, separation, identification and quantification of belowground volatile compounds have to be developed, taking into account their potential modifications in the rhizosphere once released by the roots. They enable the subsequent characterization and study of the interactions between barley and its rhizospheric partners chosen for this study. These interactions imply three types of organisms: beneficial organisms, pathogenic agents and plant and insect pests. Beneficial organisms can promote the growth of barley by the emission of volatiles; on the other hand barley can support their growth and metabolism. These phenomenons will be assessed by the study of 19 strains of plant growth-promoting bacteria (PGPR). Three pathogenic agents - two fungi (Fusarium culmorum and Cochliobolus sativus) and one virus (Barley yellow dwarf virus) - were chosen as they are known to cause various diseases on barley, especially on roots. The attractive or repellent effects of barley root volatiles on the pathogenic agents or their vectors, as well as the effect of volatiles on the diseases evolution will be evaluated. The project also includes several types of pests such as plants and insects. Plants can compete with barley for space and nutrients through volatile interactions. This will be assessed by the study of autotoxicity by barley itself and allelopathy with 8 weeds and a hemiparasitic plant (Rhinanthus minor). The effects of barley volatiles can also impact the severity of the attacks by insects. This part will be conducted with wireworms as they represent worldwide known pests, and aphids, through their viral vector role. Eventually, as soil characteristics can strongly influence the diffusion of volatile compounds, the diffusion behaviour of the identified volatile biomolecules through the soil will be modelled. Tritrophic interactions (e.g. insect-plant-pathogenic fungi) will be studied based on each bitrophic interaction results. Over-all, the Rhizovol project aims at improving the knowledge of interactions mediated by volatile compounds in the rhizosphere and at establishing new biocontrol methods that could contribute to integrated disease and pest management systems. [less ▲]

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See detailEVALUATION FOR RESISTANCE TO APHIDS OF WHEAT GERMPLASM RESOURCES IN CHINA
Zhou, Haibo ULg

Poster (2011, May 24)

Host plant resistance plays important roles in controlling pests and protecting of natural enemies in an agroecosystem, and the effect of insect resistant varieties in reducing damage is conspicuous ... [more ▼]

Host plant resistance plays important roles in controlling pests and protecting of natural enemies in an agroecosystem, and the effect of insect resistant varieties in reducing damage is conspicuous. Fuzzy recognition technique evaluation were used to determine sources of resistance in wheat to populations of the wheat aphids in five field experiments over 2 years in wheat-producing areas of China. Results showed that the majority of wheat varieties identified were susceptible to aphids, and no immune and highly resistant varieties was observed. The mean percentage from the wheat varieties with resistant, lowly susceptible, moderately susceptible and highly susceptible to aphid were 9.30%, 23.15%, 42.32%, and 25.23% in whole wheat varieties respectively. 5 wheat varieties (Lantian18, Lantian20, Lantian22, Lantian00-30 and Shanmai175) were moderately resistant in Jiangyou in 2009, other resistant sources were low levels for aphid-resisant. And more importantly, 2 wheat varieties (Lantian20, Lantian22) with the continuous resistance to wheat aphid in the five experimental fields over 2 years were found. Although resistance of wheat varieties had a close relation to their genetics and inheritance, we also found that the evaluation result of the same wheat varieties were varied in different place. The results indicated that the resistance to aphid could be affected by geographical environment.These evaluations on reaction to aphid metapopulation that could be crucial when germplasm is used in crosses to improve wheat cultivars. This research is part of program to evaluate germplasm for useful traits and make this information available to the germplasm system. [less ▲]

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See detailStand structure of mosquitoes (Diptera: Culicidae) in farms and establishment of a new potential vector of West Nile Virus for Belgium
Boukraa, Slimane ULg; Zimmer, Jean-Yves ULg; Simonon, Grégory ULg et al

Poster (2011, May 24)

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly ... [more ▼]

Many Diptera, spread across the globe are likely to play a role in the transmission of various human and animal diseases. Mosquitoes in particular, give rise to various countries on research increasingly expanded and deepened. To better understand the structure of the Culicidae at cattle farms in Belgium and identify habitats favorable to the development of each species, a taxonomic inventory was conducted in 2008 and 2009 in ten different sites. They fall into five natural regions: Condroz, Ardenne, Fagne-Famenne, Lorraine and Compine. The collection of mosquitoes is based on sampling of larvae in 13 biotopes such as water troughs, tires, abandoned utensils and temporary puddles or not. The results of the morphotaxonomic study of the mosquitoes collected in the different study sites show the presence of five species of Culicidae divided into three genera, Anopheles, Culex and Culiseta. Of the 1843 individuals examined in 2009, Culex pipiens represents 79.98% of the total harvest. A new species is reported for Belgium, Culex modestus Ficalbi, 1890. This species is one of the most important from an epidemiological and medical-veterinary entomology, given its role in the transmission of West Nile and myxomatosis viruses. [less ▲]

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See detailA semiochemical enhancing the attractiveness of aphidophagous predators in potato crops
Leroy, Pascal ULg; Vandereycken, Axel ULg; Sabri, Ahmed ULg et al

Poster (2011, May 24)

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but ... [more ▼]

Aphids are major pests of crops worldwide and the use of pesticides has led to resistant populations. The integration of aphid natural enemies in integrated management programs could be an option, but their efficacy is often limited by their quick dispersal from the ecosystem where they are released. Here, using wind-tunnel and field experiments, we have demonstrated that 3-Methyl-2-butenal acts as an efficient attractant and ovipositional stimulant for the hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae), enhancing its efficiency as biological control agent in crop fields. Wind-tunnel assays allowed determining that a minimal dose of 250 µg of 3-Methyl-2-butenal is required to attract the hoverflies over a distance of 2.5 m while a minimal dose of 500 µg is needed to induce the oviposition. Both attraction and oviposition increased proportionally to the tested doses showing that hoverflies are able to regulate their oviposition according to the chemical stimuli from their environment. In field experiments, both Syrphidae and Chrysopidae were strongly attracted by the 3-Methyl-2-butenal at a dose of 10 mg which also induces the oviposition of these two aphid predators in potato crops. This study also highlighted that hoverflies are the most abundant aphid predators found in natural environment. Against aphids, the use of this semiochemical could certainly enhance the efficiency of natural enemies. Furthermore, the use of the chemical cue 3-Methyl-2-butenal could provide a novel approach to control aphids in field and greenhouse systems. [less ▲]

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See detailActivity-Flexibility and Stability Relationships as revealed by multiple mutants of a psychrophilic alpha-Amylase
Cipolla, Alexandre ULg; D'Amico, Salvino ULg; Feller, Georges ULg

Poster (2011, May 23)

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have ... [more ▼]

Permanently cold environments, like polar regions, have been colonized by a great variety of psychrophilic organisms producing enzymes adapted to function efficiently at low temperatures. We have investigated the role of weak interactions in thermal adaptation of proteins by site-directed mutagenesis of the psychrophilc alpha-amylase (AHA) from the Antarctic bacterium Pseudoalteromonas haloplanktis. Two stabilized multiple-mutants (Mut5 and Mut5CC) have been constructed. The single mutations were selected by comparison of the presence of weak interactions in a mesophilic homolog from pig pancreas, PPA. The three enzymes AHA, Mut5 and Mut5CC have been analyzed by differential scanning calorimetry, thermal and chemical denaturation. The flexibility has been studied by acrylamide-induced fluorescence quenching. In order to investigate the kinetic origin of the gain in stability, the kinetics of unfolding and refolding in GdmCl have been monitored at 15°C. The newly introduced weak interactions stabilized the mutants, protected them against heat and chemical unfolding and also induced an effective loss of flexibility. In addition, the two multiple-mutants exhibit an increased optimum temperature for activity. The first results of kinetic studies show a similar refolding phase but differences between the three amylases in the unfolding phase. These results 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 detailBelgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008
Peeters, Alexandre ULg

Poster (2011, May 21)

Abstract: This poster relates the results of the Belgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008. These explorations were only possible thanks to the Serbian cavers of ASAK ... [more ▼]

Abstract: This poster relates the results of the Belgo-Serbian explorations on the massif of Durmitor (Montenegro) since 2008. These explorations were only possible thanks to the Serbian cavers of ASAK that we met in Lazareva, training camp in Serbia. Thereafter, the Serbian cavers gave us the opportunity of an exploration on the massif of Durmitor. For the Belgian cavers, this exploration was part of the federal training project Explo2009, whose purpose is to train the young cavers underground exploration. Regarding the results of these explorations, this poster details the discovery of the three main caves: Pedina sa ledom pod Bandijerne, l’ébouleuse and Fliš. Pedina sa ledom pod Bandijerne has long been known because of its entry porch which can be seen from the camp. With the discovery of a new passage in the chamber that follows the entrance, the exploration of this new réseau was done by the Serbian cavers in 2008 and was continued by the Belgian cavers in 2009, reaching the depth of 141 m.L’ébouleuse, which is near the Minin Bogaz pass, has been discovered in 2009. It has been completely explored in several days, reaching the bottom of the cave at the depth of 113 m. Last but not least, the main result of these explorations is Fliš. The exploration of this deep cave began in 2009 and is still in progress. The depth of 432 m was reached in 2009 and then 582 m in 2010. This cave is characterized by deep pits in which we can see the sequence of the sedimentary rocks, called Flysch. [less ▲]

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See detailZebrafish Skeleton Measurements using Image Analysis and Machine Learning Methods
Stern, Olivier ULg; Marée, Raphaël ULg; Aceto, Jessica ULg et al

Poster (2011, May 20)

The zebrafish is a model organism for biological studies on development and gene function. Our work aims at automating the detection of the cartilage skeleton and measuring several distances and angles to ... [more ▼]

The zebrafish is a model organism for biological studies on development and gene function. Our work aims at automating the detection of the cartilage skeleton and measuring several distances and angles to quantify its development following different experimental conditions. [less ▲]

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See detailEvaluation of the use of VEGF111 for the treatment of tendon lesions.
Janssen, Lauriane ULg; Kaux, Jean-François ULg; Drion, Pierre ULg et al

Poster (2011, May 20)

Alterations of tendons are common pathologies resulting from repetitive or abnormal mechanical sollicitations. Very frequently lesions become chronic and may even lead to rupture. As there is no current ... [more ▼]

Alterations of tendons are common pathologies resulting from repetitive or abnormal mechanical sollicitations. Very frequently lesions become chronic and may even lead to rupture. As there is no current efficient treatment for curing this type of diseases, new therapeutic approaches are being tested and developed. Injection of platelet-rich plasma (PRP) seems to be a promising treatment by local release of growth factors. Among these factors, VEGF-A is known to induce positive effects on vascular functions and angiogenesis, and could be implicated in the healing process of tendons. Several isoforms of VEGF-A have been described in literature, including VEGF165 and 121. VEGF111 is encoded by exons 1-4 and 8a. The lack of exon 5 enables VEGF111 to resist to proteolytic degradation and the absence of exons 6 and 7 reduces its affinity for several macromolecules present on the cell surface and in the extracellular matrix. In vivo, it has been shown to be highly proangiogenic and diffusible. A 5mm defect was surgically performed in the Achilles tendon of 60 rats. Two hours after closure of the fascia and the skin, an injection within the wound was performed with PBS alone (n=30) or with PBS containing 100 ng of VEGF111 (n=30). 10 rats of each group were sacrificed at days 5, 15 and 30. The operated tendon was then carefully removed and collected for either immunohistochemical analyses or mechanical testing. At each time point, the section and the overall appearance of the repairing tendons were similar for PBS and VEGF111-injected tendon. As compared to controls, injection of VEGF111 seemed to promote a faster angiogenesis, although the number of samples was at this stage too low for performing reliable statistical analysis. Mechanical resistance to rupture of the repairing tendons was also measured. No difference between the two groups was observed after 5 or 15 days. By contrast, increased tensile strength was clearly evidenced in the VEGF-treated group after 30 days. These preliminary data seem to indicate a positive effect of a single VEGF111 injection for restoring the mechanical properties of tendons after their section. Additional experiments are planned for confirmation purposes and for further characterizing the model. It includes a “dose- response” analysis, the use of VEGF165 as an additional control and a study evaluating the effect of several injections. [less ▲]

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See detailLa guerre à Gaza (2009): état d'insécurité après la redéfinition des frontières du conflit israélo-arabe?
Wintgens, Sophie ULg; Piet, Grégory ULg; Stans, David ULg

Poster (2011, May 17)

Près de deux ans après la guerre à Gaza et l’opération israélienne « Plomb durci » (hiver 2008-2009), il est riche d’enseignements de tirer le bilan de cet événement ayant des répercussions locales ... [more ▼]

Près de deux ans après la guerre à Gaza et l’opération israélienne « Plomb durci » (hiver 2008-2009), il est riche d’enseignements de tirer le bilan de cet événement ayant des répercussions locales, régionales et internationales. La présente communication propose de donner les résultats d’une recherche menée pendant plus d’un an sur les conséquences de la guerre à Gaza (2009) à un niveau local (relation conflictuelle entre Israël, l’autorité palestinienne et le Hamas), et aux niveaux régional et international. La question de la frontière « virtuelle » entre Israël, ses voisins moyen-orientaux et ses partenaires internationaux est donc au centre de notre recherche. Cette communication se propose de livrer une vision originale de l’implication des relations internationales et de l’État dans la résolution d’un conflit, et de démontrer la rémanence d’un conflit dépassant les seules frontières de la Palestine et d’Israël. Pour ce faire, nous posons deux éléments essentiels dans la redéfinition des frontières du conflit : d’une part, l’opposition politique intra-palestinienne (autorité palestinienne vs. Hamas) et, d’autre part, les jeux de recomposition régionale autour du Hamas en tant que nouvel interlocuteur ou en tant qu’enjeu régional contre l'Etat israélien. Partant, trois axes de recherche sont privilégiés : le dépassement du conflit israélo-palestinien, la redéfinition des acteurs et enjeux régionaux et l’implication nouvelle d’acteurs étatiques hors de la région moyen-orientale. Le tout réside dans un état d’insécurité constant pour la région et pour l’État israélien au regard des enjeux et des recompositions régionales. La première approche nous permet de dépasser la seule lecture israélo-palestinienne du conflit en reprenant les stratégies israéliennes d’isolement du Hamas et les tensions entre l’autorité palestienne et l’acteur principal de la bande de Gaza. Ce que la guerre à Gaza (2009) a par exemple modifié dans le conflit global israélo-palestinien, c’est la prise en considération du Hamas en tant qu’interlocuteur dans les négociations. Avant cet événement, ce statut était exclu étant entendu que la scène internationale considérait le Hamas comme un groupe terroriste avec lequel la négociation ne pouvait se faire. La deuxième approche proposée par cette communication rejoint une analyse de la redéfinition des frontières du conflit israélo-palestinien en promouvant un élargissement de ce dernier : préférant le qualificatif « israélo-arabe ». Nous démontrerons en effet que la considération israélo-arabe du conflit a, à nouveau, un intérêt certain. Partant, notre analyse axe, d’une part, son argument sur une prise en compte du Hamas par les États régionaux. Cette distinction est nécessaire pour comprendre comment la cause palestinienne peut tantôt faire l’objet d’un réel soutien de la part d’État régionaux, comme la Turquie, mettant un terme à des contrats avec Israël dès le conflit, tantôt être un « prétexte » de la part d’États régionaux, utilisant et instrumentalisant la confrontation avec Israël pour servir leurs propres intérêts. Nous pourrons dans ce cadre recourir à une étude portant sur la manière dont l’opinion publique a perçu le rôle des acteurs régionaux avec la consécration du président iranien comme défenseur de la cause palestinienne et l'arrivée de la Turquie dans le jeu régional se détachant un peu plus de l’Union européenne. Enfin, il convient, dans une troisième approche, d’élargir notre étude à l’implication de la scène internationale dans la région et aux nouvelles alliances. Le cas français est intéressant à ce propos car il se trouve en tension entre un soutien à Israël, sa relation avec la Syrie et une volonté de revenir en tant qu’acteur important au Moyen-Orient. Au même titre, la position américaine et, plus particulièrement, la politique d’Obama souhaitant se démarquer de la politique de Bush (cf. discours du Caire, juin 2009) relèvent d’un intérêt certain pour notre étude des nouvelles frontières du conflit israélo-arabe. [less ▲]

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See detailInsertional mutagenesis to select mutants for modified hydrogen photoproduction in Chlamydomonas reinhardtii
Godaux, Damien ULg; Emonds-Alt, Barbara ULg; Cardol, Pierre ULg et al

Poster (2011, May 17)

The unicellular green alga Chlamydomonas reinhardtii has evolved the ability to redirect electrons from the photosynthetic chain to drive hydrogen production via chloroplast oxygen-sensitive hydrogenases ... [more ▼]

The unicellular green alga Chlamydomonas reinhardtii has evolved the ability to redirect electrons from the photosynthetic chain to drive hydrogen production via chloroplast oxygen-sensitive hydrogenases. This process occurs under anaerobic conditions and provides a biological basis for solar-driven hydrogen production. Nevertheless, the yield is a major limitation for an economic viability and fundamental knowledge is still needed in order to have a better understanding of the process. In 2000, Melis and co-worker defined a protocol allowing a sustainable hydrogen production in sulfur deprivation condition. By adjustment of an existent protocol called the Winkler test, we are trying to isolate mutants with an attenuated photosynthesis to respiration capacity ratio (P/R ratio). This kind of mutants could be able to reach anoxia needed for hydrogenases activity without the stressful impact of sulfur deprivation. An insertional mutagenesis of Chlamydomonas has been carried out with an hygromycin resistance cassette and about 2500 transformants have generated and screened by the adapted Winkler test. We have isolated several oxygen-consuming mutants and the most promising one is subject to functional, molecular and genetic characterization. To discover new genes involved in hydrogenases activity, we are also planning to screen the same insertional library for mutants with attenuated levels of hydrogen photoproduction, using sensitive chemochromic sensor films which turn in blue in presence of hydrogen. We are currently making the chemochromic sensor WO3 films by dip-coating which is on the brink of being useable. [less ▲]

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See detailChitosan-based nanofibers for wound dressing
Aqil, Abdelhafid ULg; Tchemtchoua Tateu, Victor ULg; Colige, Alain ULg et al

Poster (2011, May 12)

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See detailSynthesis and characterization of reversibly core cross-linked micelles sensitive to reductive environment
Cajot, Sébastien ULg; Danhier, F.; Collodoro, M. et al

Poster (2011, May 12)

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See detailDétermination de la stabilité de l'huile de Cactus
Zine, Salma; El Hadek, Miloud; Hassani, Lalla Mina Idrissi et al

Poster (2011, May 12)

Les travaux que nous avons effectués sur l'étude de l'oxydation et de la conservation des huiles ont montré que l'huile d'argan peut être conservée pour une durée de 400 jours sous azote et à l'obscurité ... [more ▼]

Les travaux que nous avons effectués sur l'étude de l'oxydation et de la conservation des huiles ont montré que l'huile d'argan peut être conservée pour une durée de 400 jours sous azote et à l'obscurité. Les travaux que nous avons effectués sur l'étude de l'oxydation et de la conservation des huiles ont montré que l'huile d'argan peut être conservée pour une durée de 400 jours sous azote et à l'obscurité. [less ▲]

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See detailProgress in cobalt-mediated radical polymerization
Debuigne, Antoine ULg; Hurtgen, Marie ULg; Piette, Yasmine ULg et al

Poster (2011, May 12)

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See detailDesign of Photoreactive Orthosteric GABAA Ligands Potentially Useful for Studying Localization and Function of GABAA Receptors
Francotte, Pierre ULg; Nielsen, Birgitte; Krogsgaard Larsen, Povl et al

Poster (2011, May 08)

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See detailHigh-resolution measurements of an upwelling filament during the CAIBEX survey
Troupin, Charles ULg; Sangrà, Pablo; Arístegui, Javier et al

Poster (2011, May 02)

Upwelling filaments have been studied for several years. We aim to explain the general process in terms of potential vorticity: An injection of positive vorticity north of the Cape forces the jet to turn ... [more ▼]

Upwelling filaments have been studied for several years. We aim to explain the general process in terms of potential vorticity: An injection of positive vorticity north of the Cape forces the jet to turn offshore, in virtue of the principle of vorticity conservation. The Regional Ocean Modeling System (ROMS) is implemented in the Cape Ghir region, with horizontal resolution lower than 1 km. A set of process-oriented experiments has been designed in order to determine the mechanisms at the origin of the filament. [less ▲]

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See detailSpatial dynamics of wild boar population: Insights from a hunters' survey
Morelle, Kevin ULg; Lejeune, Philippe; Mengal, Coralie ULg

Poster (2011, May 02)

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See detailKynurenine administration suppresses cortical spreading depression in rat and the effect size is sex hormone dependent
Chauvel, Virginie ULg; Vamos, Eniko; Pardutz, Arpat et al

Poster (2011, May)

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See detailCaractérisation physicochimique et évaluation de la qualité des dattes des cultivars de palmier dattier de la région de Figuig
Hasnaoui, A.; ElHoumaizi, M. A.; Hakkou, A. et al

Poster (2011, May)

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See detailWhen the nursing workload measurement among comatose patients becomes a reality …
THONON, Olivier ULg; BOULANGER, Jean-Marie ULg; BAKAY, Tahar ULg et al

Poster (2011, May)

The neurologic unit of the Academic Hospital of Liège is composed of 30 beds. This is one of reference's centers for detection and differentiation of the comatose patients. With the mediatization of the ... [more ▼]

The neurologic unit of the Academic Hospital of Liège is composed of 30 beds. This is one of reference's centers for detection and differentiation of the comatose patients. With the mediatization of the Pr S. Laureys's findings, our reference's center accommodate more and more comatose patients from different European countries. With the arrival and the increase of these comatose patients, the nurses had the feeling of an increase workload by report to all others neurologic patients. The purpose of this overview is initially to be able to measure the nursing workload among comatose patients and to demonstrate that this one, within a neurology unit of an academic Belgian hospital, is heavier than that of other patients suffering from neurologic affections. [less ▲]

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See detailEffect of benzoic acid analogs on myeloperoxidase activity measured by a new technique to study their direct interaction with the enzyme.
Franck, Thierry ULg; Mazloum, Ali; Mouithys-Mickalad, Ange ULg et al

Poster (2011, May)

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human ... [more ▼]

Myeloperoxidase (MPO) plays a key role in inflammatory response and constitutes a target for new drug development. The effects of some benzoic acid analogs were studied on the specific activity of human MPO measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”), an original method that consists of incubation of the compound with MPO, followed by capture of the enzyme by specific antibodies, washing (elimination of the compounds) and enzymatic detection of the immunocaptured enzyme. The compounds tested at 10-4, 10-5 and 10-6 M were studied in terms of structure activity relationship. Gallic acid (3,4,5-trihydroxybenzoic acid) with 3 hydroxyl groups had an important dose dependent inhibitory effect on MPO activity. Other molecules with less or without hydroxyl groups [3,4-dihydroxybenzoic acid, 2-hydroxybenzoic acid (salicylic acid) and benzoic acid] had rather an activator effect at 10-5 and 10-6 M. 2,4,6-Trihydroxybenzoic acid, with two hydroxyl groups adjacent to the carboxyl group, had a less efficient inhibitory effect. Caffeic acid (3,4-dihydroxycinnamic acid) with a propenoic acid group presented a dose dependent inhibitory effect on MPO activity contrary to its analog 3,4-dihydroxybenzoic acid. The esterification of the carboxyl group of gallic acid to obtain propyl gallate induced an activation of MPO at 10-5 and 10-6 M. Finally, the substitution of one or two hydroxyl groups by methoxyl ones (ferulic and syringic acids) decreased the efficiency of the molecules on the enzyme inhibition. The SIEFED technique appears as an innovative pharmacological tool to study the direct interaction of compounds with MPO. Number and position of hydroxyl groups and the extension of the carboxyl group of benzoic acid play a crucial role in the inhibition of MPO activity probably by facilitating the interaction with the active site or another elements of the enzyme structure. [less ▲]

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See detailInvolvement of z-MMP-2 in Zebrafish lymphangiogenesis
Paupert, Jenny ULg; Pendeville, Hélène; Detry, Benoît ULg et al

Poster (2011, May)

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See detailThe antiangiogenic 16K prolactin disturbs functional tumor neovascularization by affecting vessel maturation
Nguyen, Ngoc-Quynh-Nhu ULg; Castermans, Karolien; Berndt, Sarah et al

Poster (2011, May)

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K ... [more ▼]

16K hPRL, the antiangiogenic 16-kDa N-terminal fragment of human prolactin was shown to prevent tumor growth and metastasis by modifying tumor vessel morphology. Here we investigated the effect of 16K hPRL on tumor vessel maturation and on the related signaling pathways. We show that 16K hPRL treatment leads, in a murine B16-F10 tumor model, to a dysfunctional tumor vasculature with reduced pericyte coverage, and disruption of the PDGF-B/PDGFR-B, Ang/Tie2, and Delta/Notch pathways. In an aortic ring assay, 16K hPRL impairs endothelial cell and pericyte outgrowth from the vascular ring. In addition, 16K hPRL prevents pericyte migration to endothelial cells. This event was independent of a direct inhibitory effect of 16K hPRL on pericyte viability, proliferation, or migration. In endothelial cell-pericyte cocultures, we found 16K hPRL to disturb Notch signaling, this being the first time such an effect is observed with an endogenous antiangiogenic agent. These findings provide new insights into the mechanisms of 16K hPRL action and highlight its potential for use in anticancer therapy. [less ▲]

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See detailAnnotating optical images from ROVs or towed cameras in Vulnerable Marine Ecosystems studies
Guillaumont, Brigitte; Carré, Cyril ULg; Van Den Beld et al

Poster (2011, May)

Detailed reference viewed: 125 (28 ULg)
Peer Reviewed
See detailAcaricidal activities of Santolina Africana and Hertia Cheirifolia, two endemic plants of north Africa, on the two spotted spider mite (Tetranychus urticae)
Attia, Sabrine; Grissa, Kaouthar Lebdi; Le Goff, Guillaume et al

Poster (2011, May)

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of ... [more ▼]

The two-spotted spider mite, Tetranychus urticae Koch, is a worldwide pest which feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of new biological control tactics for population management is crucial. Plant extracts, such as Santolina africana and Hertia cheirifolia (Asteraceae), may represent viable alternatives, since they are currently considered to be minimumrisk pesticides. Although these two plants are known for their biocidal properties, the extract concentration that provides the most efficient control has not yet been precisely determined. In this study, we conducted a series of laboratory experiments to determine the susceptibility of adult females to different concentrations of S. africana and H. cheirifolia extract. These plants were steam-distilled and sprayed using a Potter spray tower. Mortality and fecundity were measured upon treatment with extract concentrations ranging from 0.07 to 6.75 mg/L. Female mortality increased with concentration, with LD50 values of 2.35 mg/L for S. africana and 3.43 mg/L for H. cheirifolia, respectively Reduced fecundity was previously observed at concentrations of 0.07, 0.09 and 0.29 mg/L .The chemical composition of the two oils were characterised by GC-MS. The most abundant components of the S. africana oil were terpinen-4-ol (44%), α- terpineol (11.31%) and borneol (6.73%). Camphor (15.11%), terpinen-4-ol (14.2%), α- terpineol (9.3%) were characteristic of the Hertia oil. [less ▲]

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See detailRadiation-induced malignant peripheral nerve sheat tumors – a report of 2 cases
PHAN BA, Remy ULg; BELACHEW, Shibeshih ULg; JEDIDI, Zayd ULg et al

Poster (2011, May)

We discuss the case of two patients who developped delayed malignant peripheral nerve sheath tumor (MPNST) following radiotherapy. Case report: the first patient is a sixty year-old woman with a 2 years ... [more ▼]

We discuss the case of two patients who developped delayed malignant peripheral nerve sheath tumor (MPNST) following radiotherapy. Case report: the first patient is a sixty year-old woman with a 2 years history of right cervicobrachial pain and weakness. The neurological examination depicted severe weakness, atrophy and loss of sensation in the right C5 and C6 territories. A subclavicular hardened and enlarged lymph node was noted. Her past medical history was notable for a Hodgkin’s disease (HD) treated with radiation therapy (>40Gy) 35 years earlier. Brachial plexus MRI revealed a tumoral mass arising from the right brachial plexus. Biopsy of the subclavicular mass revealed a poorly differentiated malignant tumour consisting of spindle cells showing moderate polymorphism and a high mitotic index. Immunohistochemistry showed positivity for the S-100 protein, the CD56 and for the epithelial membrane antigen (EMA) and a diagnosis of MPNST of the brachial plexus was proposed. The second case is a 36 year-old man referred for a history of right sciatic neuralgia that appeared 3 years earlier. The medical history of the patient was notable for a right seminoma, treated by orchidectomy and prophylactic radiotherapy (24 Gy) 5 years earlier. The neurologic examination revealed right L5 and S1 radicular territories involvement, and the CT of the pelvis demonstrated a nodular mass at the level of the greater sciatic foramen. A surgical biopsy was performed and the neuropathological findings were consistent with a diagnosis of low-grade MPSNT. Discussion: MPNSTs are rare tumors accounting for 3 to 10% of all tissues sarcomas. Half of the cases described are sporadic, while the other half tend to appear in patients suffering from tumor prone conditions, such as neurofibromatosis type 1. Although secondary neoplasms are known complications of radiotherapy, descriptions of peripheral nerve sheath tumors (PNST) are scarce. The exact pathophysiology of radiation-induced PNSTs remains unclear but vascular alterations, direct damages to axon or Schwann cell and nerve compression by soft tissue fibrosis are thought to play a role. Although surgical removal sometimes followed by chemotherapy is the mainstay of MPNSTs, they usually carry a poor prognosis. Our 2 cases emphasize that the possibility of radiation-induced MPNST has to be kept in mind when investigating a localized neuropathy in a previously irradiated area. [less ▲]

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See detailTreatment of a case of trichurosis (Trichuris suis) in pigs
Caron, Yannick ULg; Delleur, Valery; De Bock, Bart et al

Poster (2011, May)

Trichuris suis infection was identified in a pig herd during an investigation into persistent diarrhea and weight loss in 10 recently introduced gilts. Eggs of the parasite were identified in faeces of ... [more ▼]

Trichuris suis infection was identified in a pig herd during an investigation into persistent diarrhea and weight loss in 10 recently introduced gilts. Eggs of the parasite were identified in faeces of gilts. Further investigations failed to detect other causes of diarrhea but, in all production stages, they allowed the detection of eggs of Trichuris suis that could explain pasty faeces sometimes observed in weaned sows and frequent diarrhea found in the early fattening period. The administration of levamisole (intramuscular injection) to gilts allowed the excretion of adult parasites, the treatment of diarrhea and the reduction of the number of eggs per gram of faeces. Taking into account the success obtained with levamisole in gilts, the equipment of the farm and the wish of the farmer no to inject finishing pigs, an unsuccessful treatment was tried based on levamisole in drinking water every 8 and then 5 weeks. Flubendazole was finally administrated in drinking water every 3 and then 5 weeks, reducing significantly the number of eggs per gram of faeces. [less ▲]

Detailed reference viewed: 98 (17 ULg)
See detailAssessing the World Ocean ventilation timescales with simple analogs - the leaky funnel model
Mouchet, Anne ULg; Deleersnijder, Eric

Poster (2011, May)

Detailed reference viewed: 12 (0 ULg)
See detailOxygen, a tool for assessing ocean tracer transport models
Mouchet, Anne ULg; Campin, Jean-Michel

Poster (2011, May)

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See detailEstablishment of an interactomic map of the Ets factors family: Towards a better understanding of their roles in oncogenic processes
Rambout, Xavier ULg; Simonis, Nicolas; Demoitié, Pauline et al

Poster (2011, April 29)

Ets transcription factors have been involved in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling important biological processes such ... [more ▼]

Ets transcription factors have been involved in several cancers such as leukemia, prostate cancer and Ewing’s sarcoma. They regulate the expression of genes controlling important biological processes such as cellular proliferation, differentiation, apoptosis, metastasis, and transformation. This family of transcription factors is characterized by its highly conserved DNA-binding domain called the ETS domain and members are classified into subfamilies based on sequence homology criterion. We built a protein-protein interaction (PPI) network of the 27 Ets proteins and of their individual functional domains using a high-throughput yeast-two hybrid (Y2H) screening method. That Y2H network was expanded with confident literature-curated PPIs to obtain a comprehensive Ets interaction network. By considering connectivity between Ets interaction partners, we were able to segregate highly connected clusters of proteins from that network. Analysis of ontologies enrichment of those clusters enabled to confirm well-established roles and regulations of Ets factors, but also to suggest new ones. Biological validation of one precise cluster could be used as a rule of a thumb to globally confirm the bioinformatic analysis of our Ets PPI network and the potential physiological or pathological roles and regulation of Ets factors. [less ▲]

Detailed reference viewed: 36 (10 ULg)
See detailNew fluorinated surfactant for nanogels preparation in supercritical CO2
Alaimo, David ULg; Beigbeder, Alexandre; Dubois, Philippe et al

Poster (2011, April 29)

Detailed reference viewed: 42 (7 ULg)
See detailChitosan-based wound dressings produced by electrospinning
Croisier, Florence ULg; Sorlier, Pierre; Jérôme, Christine ULg

Poster (2011, April 29)

Detailed reference viewed: 36 (2 ULg)
See detailNovel amphiphilic copolymers and design of smart nanoparticles for drug delivery systems
Cajot, Sébastien ULg; Danhier, F.; Lautram, N. et al

Poster (2011, April 29)

Detailed reference viewed: 37 (13 ULg)
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See detailNuclear Magnetic Resonance and Nuclear Waste Reprocessing.
Vidick, Geoffrey ULg; Bouslimani, Nouri; Desreux, Jean-François ULg

Poster (2011, April 29)

Detailed reference viewed: 32 (2 ULg)
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See detailFat analysis in muscle samples from horses affected with atypical myopathy
Van Galen, Gaby ULg; Deby-Dupont, G; Serteyn, Didier ULg et al

Poster (2011, April 15)

Detailed reference viewed: 34 (7 ULg)
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See detailVariability of methane in the epilimnion of Lake Kivu
Borges, Alberto ULg; Abril, G.; Delille, Bruno ULg et al

Poster (2011, April 08)

Detailed reference viewed: 21 (1 ULg)
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See detailSeasonal and inter-annual variability of air-sea CO2 fluxes and seawater carbonate chemistry in the Southern North Sea
Gypens, N.; Lacroix, G.; Lancelot, C. et al

Poster (2011, April 08)

Detailed reference viewed: 11 (3 ULg)
Peer Reviewed
See detail2500 years record of trace element metal in the Misten peat bog (Hautes Fagnes), Belgium
Allan, Mohammed ULg; Fagel, Nathalie ULg; Le Roux, Gael et al

Poster (2011, April 08)

The Misten peat bog provides a record of atmospheric deposition in the Hautes Fagnes Plateau (East Belgium). A composite 185cm core (W01/01b) was studied for its trace metal content (TM) and its lead ... [more ▼]

The Misten peat bog provides a record of atmospheric deposition in the Hautes Fagnes Plateau (East Belgium). A composite 185cm core (W01/01b) was studied for its trace metal content (TM) and its lead isotopic signature. The peat bog accumulation allows following the history of atmospheric TM deposition during the last 2500 years. TM enrichment factors coupled with a continuous decrease in 206Pb/204Pb, 207Pb/204Pb,208Pb/204Pb isotopic ratios from 494-732AD to1969-1977 AD evidence the increasing importance of TM released by anthropogenic activities. The highest concentrations of TM are found near the surface of the bog; at depths from 30 to 19 cm. Historical records of Cu, Zn, As, Sb, and Pb atmospheric flux during the Industrial Revolution and pre-industrial periods were derived. Maximum fluxes (up to 7.3, 89, 2.4, 1.5, and 116 mg.m-2.y-1, respectively) occurred in peat layers dated from 1619-1877AD to 1992-2000AD, reflecting anthropogenic emissions from diverse sources such as mining, coal combustion, and emissions from the use of leaded gasoline. The TM enrichment factors also increased significantly during the Industrial Revolution until a reduction at the end of the 70’S due to the progressive abolition of the leaded gasoline. [less ▲]

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See detailFirst assessment of the biogeochemistry of the Congo River and tributaries
Darchambeau, François ULg; Bouillon, S.; Wabakanghanzi, J. N. et al

Poster (2011, April 08)

Detailed reference viewed: 26 (2 ULg)
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See detailCarbon exchange in a Belgian grassland with cattle
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2011, April 08)

Detailed reference viewed: 79 (21 ULg)
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See detailParticipatory valuation and modelling of ecosystem services under land use change
Jacquemin, Ingrid ULg; Fontaine, Corentin M.; De Vreese, Rik et al

Poster (2011, April 08)

Ecosystem service (ES) is a conceptual linkage between biodiversity and human well-being. In a context of increased urbanization combined with the effects of climate change, the level of biodiversity is ... [more ▼]

Ecosystem service (ES) is a conceptual linkage between biodiversity and human well-being. In a context of increased urbanization combined with the effects of climate change, the level of biodiversity is expected to be reduced, and from the point of view of the ES, the loss of biodiversity is not only an environmental problem for itself, but is also a major issue for society’s sustainable development. Thus, it is necessary to identify adaptations of ecosystem use and management that will minimize the biodiversity loss while maintaining the production of ES for the society. To achieve this goal, ES must be valuated, but this valuation needs to consider a broad set of goals that include ecological sustainability and social fairness, along with the traditional economic goal of efficiency. Participatory approaches should be used in all ES valuation steps. Indeed, local stakeholders and end-users have a central role in the valuation process, as they are the direct beneficiaries of the provision of services. Moreover, biodiversity management must be focused onto human needs to deliver more integrated policy and management at a landscape-scale and be more firmly directed towards human well-being. Here, we present the framework developed within the VOTES (Valuation Of Terrestrial Ecosystem Services in a multifunctional peri-urban space) project for integrating all these factors in a quantitative tool designed for a sustainable landscape management, as well as for the evaluation and the monitoring of ES for policy designers. The originality is that this framework will provide an integrated valuation of ES in a spatially and temporally explicit way, based on the following steps: social valuation, biophysical valuation, economic valuation, landscape modelling & dynamics and finally integration of ecosystem service indicators. The biophysical assessment and landscape modelling steps rest on the combined use of two spatial models: a dynamic vegetation model (CARAIB DVM) and an agent-based model (ABM). These models will be used to construct future (dynamic) scenarios that include the major driving forces of the system (e.g., global socio-economic context, urbanization pressure, climate change, etc) together with adapted management. The computed scenarios will provide the changes in the biophysical system consistent with the socio-economic evolution, including changes in land use, crop productivity, carbon sequestration, or more generally ecosystem structure and function. This will allow an estimate of a change in the provision of ES through time, so that the sustainability of ES under the studied scenarios can be assessed. The framework is meant to be applicable to any given landscape, but here it is applied to a case study area in central Belgium, known for its strong periurban character, due to the proximity to Brussels. [less ▲]

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See detailThe interglacial carbon cycle
Kleinen, Thomas; Brovkin, Victor; Munhoven, Guy ULg et al

Poster (2011, April 07)

Explaining the difference in carbon cycle dynamics (and hence atmospheric CO2) between various interglacials is an elusive issue. Several biogeochemical mechanisms of different origin are involved in ... [more ▼]

Explaining the difference in carbon cycle dynamics (and hence atmospheric CO2) between various interglacials is an elusive issue. Several biogeochemical mechanisms of different origin are involved in interglacial CO2 dynamics, leading to a CO2 release from the ocean (carbonate compensation, coral growth) compensated by a land carbon uptake (biomass and soil carbon buildup, peat accumulation). The balance between these fluxes of CO2 is delicate and time-dependent, and it is not possible to provide firm constraints on these fluxes from proxy data. The best framework for quantification of all these mechanisms is an Earth System model that includes all necessary physical and biogeochemical components of the atmosphere, ocean, and land. To perform multi-millennial model integrations through the Holocene, Eemian, and MIS11, we use an earth system model of intermediate complexity, CLIMBER-2, coupled to the dynamic global vegetation model LPJ with a recently implemented module for boreal peatland dynamics. During glacial-interglacial cycles, the carbon cycle never is in complete equilibrium due to a number of small but persistent fluxes such as terrestrial weathering. This complicates setting up interglacial experiments as the usual approach to start model integrations from an equilibrium state is not valid any more. In order to circumvent the problem of non-equilibrium initial conditions, the model is initialised with the oceanic biogeochemistry state taken from a transient simulation through the last glacial cycle with CLIMBER-2 only. In this simulation, the CLIMBER-2 model was run through the last glacial cycle with carbon cycle in “offline mode” as interactive components of the physical climate system (atmosphere, ocean, ice sheets) were driven by concentration of greenhouse gases reconstructed from ice cores. Using these initial conditions, we performed coupled climate carbon cycle experiments for the Holocene, the Eemian and MIS11, driven by orbital forcing. Contrary to the results we published previously (Kleinen et al. 2010), peat accumulation was not prescribed, but rather determined dynamically, making this model setup applicable to previous interglacials as well. For the Holocene, our results resemble the carbon cycle dynamics as reconstructed from ice cores quite closely, both for atmospheric CO2 and delta13CO2. These experiments will be presented, analysing the role of different forcing mechanisms. The land surface appears to be an overall sink for CO2, due to carbon accumulation in the soil, as well as peat accumulation, and oceanic contributions due to temperature and circulation changes are quite small. Finally, results for MIS11 and the Eemian will be shown. [less ▲]

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See detailIsoprene and monoterpene emissions from a mixed temperate forest
Laffineur, Quentin ULg; Heinesch, Bernard ULg; Amelynck, Crist et al

Poster (2011, April 07)

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See detailOrgano-mineral imprints in fossil cyanobacterial mats of an Antarctic lake
Lepot, Kevin ULg; Deremiens; Namsaraev, Zorigto ULg et al

Poster (2011, April 07)

Detailed reference viewed: 51 (13 ULg)
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See detailStudy of viability of Pseudomonas fluorescens BTP1 freeze-dried during storage at 4 and 20°C
Mputu Kanyinda, Jean-Noël ULg; Thonart, Philippe ULg

Poster (2011, April 05)

The drying of bacteria remains a major alternative in order to keep them long term. After centrifugation, the bacterial pellet of Pseudomonas fluorescens BTP1 was divided in two fractions one with and one ... [more ▼]

The drying of bacteria remains a major alternative in order to keep them long term. After centrifugation, the bacterial pellet of Pseudomonas fluorescens BTP1 was divided in two fractions one with and one without cryoprotectants (2% glycerol and 5% maltodextrine) and freeze-dried. After freeze drying, powders were sealed in aluminium bag under vacuum and storage at 4 or 20°C. The storage stability of freeze-dried powders was studied by parameters such as loss of viability on the Plate Count Agar (PCA) (e.g. Concentration of Cells with glycerol (PG) at CFU/g before storage 109 and after 7 month, 108 at 4°C and 107 at 20°C) and evolution in membrane composition by measuring the ratio of unsaturated/saturated fatty acid. These ratios decrease in function of time (e.g. at 4°C the ratios of C18:3 and C18:2 by C16:0 decreases respectively of 0,013 to 0,001 and 0,05 to 0,03 after 60 days of storage). Viability (%) and concentration (CFU/g) of bacterial during storage at 4 or 20°C with aw = 0,32 was determined using a procedure published by (Kurtmann et al., 2009). In the present study, flow cytometric analysis was applied to evaluate the state in which are the cells at the end of storage time. Furthermore, we compared result the survival of bacteria as obtained by plate count with the flow cytometric analysis results. [less ▲]

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See detailEvaluation of the present and future general circulation over Greenland simulated by the IPCC AR5/CMIP5 GCMs with the help of a circulation type classification
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2011, April 05)

Future projections of the Greenland ice sheet melt are based on General Circulation Model (GCM) simulations. In particular, the reliability of downscaling methods forced by these simulations depends on ... [more ▼]

Future projections of the Greenland ice sheet melt are based on General Circulation Model (GCM) simulations. In particular, the reliability of downscaling methods forced by these simulations depends on the quality of the atmospheric circulation simulated by GCMs. Therefore, it is essential to analyse and evaluate the GCMs modelled general circulation for current climate (1961-1990). Atmospheric circulation type classifications offer a very interesting approach for evaluating the GCM-based circulation at a daily time scale compared to the most used methods based only on monthly means. Indeed, the circulation type classification allows a precise and detailed analysis of each circulation type and so, it gives much more information on the ability of GCMs to simulate the different circulation types and consequently the climatic variability of a region. In fact, exceptional circulation events over Greenland, which cannot be taken into account by the monthly mean approach, have much more impact on the melt than the mean atmospheric state. Thus, an automated correlation-based atmospheric circulation type classification (CTC) is used for evaluating the new GCM outputs (available on http://cmip-pcmdi.llnl.gov/cmip5/) computed for the upcoming IPCC report (AR5). The daily geopotential height at 500 hPa simulations of the GCMs for current climate are compared to the NCEP-NCAR 1 and the ECMWF reanalysis data for the summer months (JJA), when melt is the most important. To achieve this, the classification is first done for the reanalysis data over 1961-1990 and afterwards, the types of the reanalysis based CTC are imposed for classifying the GCM datasets over 1961-1990 (from the historical experiment) to allow a direct type per type comparison based on the frequency distribution of each dataset. This approach also gives the opportunity to study the intraclass repartition differences between the reanalysis and the GCMs. After the evaluation of the GCM simulations for current climate, the future projections driven by RCP concentrations or emissions (2011-2040, 2041-2070 and 2071-2100) from the best matching GCMs are analysed in the same way. For current climate, it clearly appears that only a few GCMs are able to reproduce reliably the variability of the atmospheric circulation over Greenland during summer. The differences of frequency between the GCMs and the reanalysis are mainly due to biases of the geopotential height which is systematically over or underestimated by most GCMs and to the underestimation of the variability of the circulation by most GCMs. For future projections, no new circulation types are detected, but rather a general increase of the mean geopotential height regardless of the circulation type. It is also important to note that for many GCMs, the uncertainty of the current climate simulations (given by the differences of the classification results between the GCM simulations for current climate and the reanalysis data for the same time) are of the same order than the projected changes for future climate. Therefore, these projections may be questionable. [less ▲]

Detailed reference viewed: 81 (10 ULg)
See detailInput of 12CO2 and 13CO2 soil concentration measurements to understand trends in soil carbon production and emission.
Longdoz, Bernard ULg; Plain, Caroline; Parent, Florian et al

Poster (2011, April 05)

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See detailImpact of the spatial resolution on the Greenland Ice Sheet Surface Mass Balance modelling using the regional climate model MAR with the aim to force an ice sheet model.
Franco, Bruno ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

Poster (2011, April 05)

By using the regional climate model MAR (Modèle Atmosphérique Régional), validated for Greenland at 25km resolution and forced every 6 hours with the ERA-INTERIM reanalysis (Fettweis 2007, Fettweis et al ... [more ▼]

By using the regional climate model MAR (Modèle Atmosphérique Régional), validated for Greenland at 25km resolution and forced every 6 hours with the ERA-INTERIM reanalysis (Fettweis 2007, Fettweis et al. 2010), we have modelled the Greenland Ice Sheet (GrIS) Surface Mass Balance (SMB) at 20, 25, 30, 40 and 50km resolution to assess the impact of the spatial resolution. As part of the ICE2SEA project, the 25km-resolution SMB outputs of the MAR model are used as forcing fields for ice sheet models, in order to produce future projections of the GrIS contribution to sea-level rise over the next 200 years. Although the current spatial resolution of the MAR model (25km) is much higher than the general circulation models (GCM) resolution (150-300km), the ice sheet models often run at a higher resolution (typically 5-10km). Nevertheless, such higher-resolution runs of the MAR model on the same integration domain generate a significant additional computing time and are not doable until now. Moreover, conventional linear interpolations of the SMB outputs onto a higher-resolution grid, generally induce biases because ice sheet masks at different spatial resolutions do not match and the SMB is a very complex function of the spatial resolution and the topography . That is why several enhanced SMB interpolations are tested here in order to reduce biases when interpolating the MAR outputs onto higher resolution, in the framework of the ICE2SEA project. [less ▲]

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See detailEvolution of wind behaviour and of its potential for wind power production in Belgium during the last 30 years.
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Sacré, Bernard ULg et al

Poster (2011, April 04)

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is ... [more ▼]

The number of wind turbines in the world grows significantly every year due to politics proposing green energy productions as solutions to mitigate climate change effects. However, this kind of energy is dependent on the weather. This implies that the wind production is irregular at a very short time scale. But the short time scale availability of the wind-based energy is important to the producers of energy as well as to the electric grid managers because the wind energy production can rise or fall rapidly which creates some financial and voltage variations. For these reasons, we study the past evolution of the availability of the wind quantity by analysing the intermittence of the wind speed in Belgium during the last 30 years. To reach this goal, we use the regional model WRF (Weather and Research Forecast model) developed by the UCAR community users. The WRF model is forced by the NCEP2 Reanalysis model to obtain a regionalisation of the weather conditions over a domain centred on Belgium at a spatiotemporal resolution of 10 km and 1 min. This resolution allows to capture the minute-based time scale variability of wind speed and consequently the irregular behaviour of the wind power production. To obtain a value of the wind intermittence, we calculate the persistence of a wind blowing continuously with a minimum speed of 1 ms-1, then the persistence of a wind blowing continuously with a minimum speed of 2 ms-1, etc. The persistence of the wind speed and its evolution over 30 years are characterised by : (a) the mean wind speed over a fixed period (monthly, seasonally, … ), (b) the mean duration of a wind speed above x ms-1 over the same fixed period and (c) the evolution of (a) and (b) during the studied period. This study will show the evolution during the last decades of the wind behaviour in Belgium and its potential for electricity production. [less ▲]

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See detailParticulate carbon export during a bloom of Emiliania huxleyi in the Northwest European continental margin (northern Bay of Biscay)
Schmidt, Sabine; Harlay, Jérôme ULg; Borges, Alberto ULg et al

Poster (2011, April 03)

Coccolithophores, the dominant pelagic calcifiers in the oceans, play a key role in the marine carbon cycle through calcification, primary production and carbon export, the main drivers of the biological ... [more ▼]

Coccolithophores, the dominant pelagic calcifiers in the oceans, play a key role in the marine carbon cycle through calcification, primary production and carbon export, the main drivers of the biological CO2 pump. Massive blooms of Emiliania huxleyi are observed each year at the continental margin of the Bay of Biscay. The BG02/11 cruise (RV Belgica), supported by near-real time remote sensing data, was conducted in early May 2002, along a transect on the outer shelf of the Northern Bay of Biscay between the La Chapelle Bank (southern region of the transect) and Goban Spur (northern region of the transect) (47.0°-50.5°N, 5.0°-11.0°W). Biogeochemical variables including primary production, calcification, partial pressure of CO2 (pCO2), chlorophyll-a (Chl-a), particle load, particulate organic and inorganic carbon (POC, PIC), Th-234 were measured in surface waters to assess particle dynamics, and carbon export in relation to the development of a coccolithophore bloom. We observed a marked northward decrease in water irradiance, Chl-a concentration and calcification rates: the bloom exhibited lower values and may have been less well developed in the Goban Spur area. There was also a large northward decrease in particulate 234Th settling fluxes along the transect from La Chapelle Bank to Goban Spur. The export fluxes of POC and PIC from the top 80 m, determined using the ratios of POC and PIC to Th-234 of particles, ranged from 81 to 323 mgC m-2 d-1 and from 30 to 128 mgC m-2 d-1, respectively. The highest fluxes were observed in waters presenting a well-developed coccolithophore bloom, as shown by high reflectance of surface waters. Despite the high calcification rates at the southernmost stations, surface waters were a net sink of atmospheric CO2 during this cruise. These results tend to demonstrate the enhancement of coccolithophore blooms on the efficiency of the surface community to export carbon to deep ocean. However, improvements in the estimation of POC and PIC export during coccolithophore blooms are needed to not only understand the present calcification to primary production (C:P) ratio, but also to help understand future sequestration of organic and inorganic carbon to the deep ocean. [less ▲]

Detailed reference viewed: 69 (2 ULg)
See detailBiogeochemistry and carbon mass balance of a coccolithophore bloom in the northern Bay of Biscay (June 2006)
Harlay, Jérôme ULg; Chou, Lei; De Bodt, Caroline et al

Poster (2011, April 03)

Primary production (PP), calcification (CAL), bacterial production (BP) and dark community respiration (DCR) were measured along with a set of various biogeochemical variables, in early June 2006, at ... [more ▼]

Primary production (PP), calcification (CAL), bacterial production (BP) and dark community respiration (DCR) were measured along with a set of various biogeochemical variables, in early June 2006, at several stations at the shelf break of the northern Bay of Biscay. The cruise was carried out after the main spring diatom bloom that, based on the analysis of a time-series of remotely sensed chlorophyll-a (Chl-a), peaked in mid-April. Remotely sensed sea surface temperature (SST) indicated the occurrence of enhanced vertical mixing (due to internal tides) at the continental slope, while adjacent waters on the continental shelf were stratified, as confirmed by vertical profiles of temperature acquired during the cruise. The surface layer of the stratified water masses (on the continental shelf) was depleted of inorganic nutrients. Dissolved silicate (DSi) levels probably did not allow significant diatom development. We hypothesize that mixing at the continental slope allowed the injection of inorganic nutrients that triggered the blooming of mixed phytoplanktonic communities dominated by coccolithophores (Emiliania huxleyi) that were favoured with regards to diatoms due to the low DSi levels. Based on this conceptual frame, we used an indicator of vertical stratification to classify the different sampled stations, and to reconstruct the possible evolution of the bloom from the onset at the continental slope (triggered by vertical mixing) through its development as the water mass was advected on-shelf and stratified. We also established a carbon mass balance at each station by integrating in the photic layer PP, CAL and DCR. This allowed computation at each station of the contribution of PP, CAL and DCR to CO2 fluxes in the photic layer, and how they changed from one station to another along the sequence of bloom development (as traced by the stratification indicator). This also showed a shift from net autotrophy to net heterotrophy as the water mass aged (stratified), and suggested the importance of extracellular production of carbon to sustain the bacterial demand in the photic and aphotic layers. [less ▲]

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See detailNursing care after Transcatheter Aortic Valve Implantation with the Medtronic CoreValve Revalving® system
ERPICUM, Marie ULg; RADERMECKER, Marc ULg; DEFRAIGNE, Jean ULg et al

Poster (2011, April 02)

The risks, complications and results of the transcatheter aortic valve implantation (TAVI) are widely described. But to our knowledge, no one has yet defined the nursing cares required after this ... [more ▼]

The risks, complications and results of the transcatheter aortic valve implantation (TAVI) are widely described. But to our knowledge, no one has yet defined the nursing cares required after this procedure and their effects on the TAVI results. The aims of this review are to describe the nursing cares required after TAVI and to determine which aspects of the management could be optimized to improve the results of the procedure. [less ▲]

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See detailAtmospheric mercury deposition during the last 1500 years in We Europe: The Misten peat bog record (Hautes Fagnes - Belgium)
Allan, Mohammed ULg; Fagel, Nathalie ULg; De Vleeschouwer, François et al

Poster (2011, April)

The current rate of global atmospheric Hg deposition is approximately three times higher than the preindustrial record and it even increased by a factor of 2-10 in the industrialized regions ... [more ▼]

The current rate of global atmospheric Hg deposition is approximately three times higher than the preindustrial record and it even increased by a factor of 2-10 in the industrialized regions.....()(Hylander and Meili 2003). To determine the extent of such increase, it is necessary to quantify the atmospheric mercury concentration and its temporal variation. For this purpose four 1m Wardenaar peat cores (MIS01W, 04W, 0W5 and 06W) were collected in 2008 in the ombrotrophic Misten bog (Hautes Fagnes Plateau, East Belgium). Mercury was measured using a DMA 80 at the Laboratory of Mechanisms and Transfers in Geology in Toulouse (LMTG, France). The strongest mercury concentrations are measured in the upper half peat record, in a depth interval corresponding to the Industrial Revolution period. Mercury accumulation rate was estimated by applying a coupled 210Pb- 14C age model. The mercury accumulation rate remains relatively small, ranging between 0.9 and 3.3 g.m 2.y 1 during periods corresponding to the decline of Roman Empire and during the Middle Ages. Hg accumulation rate starts to increase when 25 cm, reaching a maximum value (> 115 g.m 2.y 1) at 13.7 cm (i.e.; 1923-1938 AD). Then the values oscillate to reach 9 g.m 2.y 1 at the peat surface (2000-2007AD). In the Misten bog, the evolution of Hg accumulation rate is in agreement with the chronology of other European peat records .......()(Roos-Barraclough et al. 2002). [less ▲]

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See detailModelling the migration of a mid-Pleistocene erosion wave in the Ardennes (western Europe) drainage network: approach and first implications
Beckers, Arnaud ULg; Bovy, Benoît ULg; Demoulin, Alain ULg

Poster (2011, April)

Model parameterization through adjustment to field data is a crucial step in the modelling and the understanding of the drainage network response to tectonic or climatic perturbations. Using a data set of ... [more ▼]

Model parameterization through adjustment to field data is a crucial step in the modelling and the understanding of the drainage network response to tectonic or climatic perturbations. Using a data set of 18 knickpoints that materialize the migration of a 0.7-Ma-old erosion wave in the Ourthe catchment of northern Ardennes (western Europe) as a test case, we explore the impact of various data fitting on the calibration of the detachment-limited stream power model of river incision, from which a simple knickpoint celerity equation is derived. Our results show that statistical least squares adjustments (or misfit functions) based either on the stream-wise distances between observed and modelled knickpoint positions at time t = 0.7 Ma or on differences between observed (0.7 Ma) and modelled time at the actual knickpoint locations yield significantly different values for the m (more exactly, m/n) and K parameters of the model. As there is no physical reason to prefer one or the other approach, we suggest that an intermediate least rectangles adjustment might be the best compromise. In the Ourthe case, this leads to a m/n value lower than that obtained from the classical distance adjustment (0.79 against 0.86), leading to an increase in the non linear character of the dependence of knickpoint celerity on discharge. If we now recall that m/n = c(1-b) (Whipple & Tucker, 1999, JGR 104B: 17661-17674), where c and b are the exponents of the power law relations respectively linking discharge to drainage area and channel width to discharge, we can compare the calculated m/n value with that derived from field measurements of channel width, discharge and drainage area in the presently graded sections of the rivers. Such data taken from Petit et al. (2005, BSGLg 46: 37-50) allow us to derive m/n = 0.48 at equilibrium. As c may be considered constant, the higher m=n value obtained from the knickpoint retreat modelling must be ascribed to a lower b, i.e., to a channel narrowing associated with the transient phase of knickpoint migration. [less ▲]

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See detailCombustion control and performance of household condensing boilers
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Poster (2011, April)

The present work presents a model that is composed of a conventional boiler model with a main counterflow gas-water heat exchanger at which a condensing heat exchanger is added. Prior to the second heat ... [more ▼]

The present work presents a model that is composed of a conventional boiler model with a main counterflow gas-water heat exchanger at which a condensing heat exchanger is added. Prior to the second heat exchanger the exhaust gas are converted to equivalent wet air as the wet heat exchanger is simulated by a cooling coil used in air treatment. Six parameters are needed for calculation and these parameters are fitted with experimental data: one test in dry regime and one test in wet regime. Steady-state tests have been performed on two household boilers (a gas-fired and a fuel oil boiler), whose nominal outputs are 24 kW in order to fit the model parameters and check the model behaviour. It seems that the model gives the correct trend for the thermal efficiency prediction. Besides, combustion controls sensors (non nernstian sensors) have been tested by varying the excess of air. In the range tested (from =1.05 to =1.25), the increase in the boiler efficiency is around 1% as the excess of air decreases. However that increase is lower than the measurement uncertainty. The developed model predicts very well that trend. The pollutants emissions have also been measured and the results show that the NOx emissions decrease as the excess air increases. [less ▲]

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See detailProfils de liaison et mécanismes d’internalisation des norovirus bovins de génotype 2
Mauroy, Axel ULg; Gillet, Laurent ULg; Mathijs, Elisabeth et al

Poster (2011, April)

Appartenant à la famille des Caliciviridae genre Norovirus, les norovirus (NoV) sont des virus non enveloppés dont le génome est composé d’un ARN monocaténaire de polarité positive d’approximativement 7,5 ... [more ▼]

Appartenant à la famille des Caliciviridae genre Norovirus, les norovirus (NoV) sont des virus non enveloppés dont le génome est composé d’un ARN monocaténaire de polarité positive d’approximativement 7,5 kb. Les NoV infectent l’homme et les animaux (bovins, porcins, murins). Chez l’homme, ils sont des agents majeurs de gastroentérite sporadique ou épidémique d’origine souvent alimentaire. Chez le bovin, ils causent également une entérite bénigne et les souches mises en cause sont classées génétiquement dans deux génotypes au sein du génogroupe III du genre Norovirus. La voie d’infection des NoV est oro-fécale, ils sont très résistants dans l’environnement et une infection peut survenir même avec une très faible dose infectieuse. Les NoV humains et animaux sont relativement proches génétiquement et coexistent parfois de manière très étroite en Europe du Nord. Il est donc logique d’envisager le risque zoonotique lié aux NoV animaux et plus particulièrement celui lié aux norovirus bovins (BoNoV). Différents systèmes d’expression protéique ont permis d’obtenir des pseudoparticules virales (VLPs) morphologiquement et antigéniquement semblables à certaines souches de NoV, difficilement cultivables en culture de cellules. Les objectifs du travail étaient d’étudier les types de structures pouvant être impliquées dans la liaison de BoNoVLP aux cellules, ainsi que les mécanismes entrant en jeu pour leur internalisation. Dans une première étude, des VLP d’une souche BoNoV obtenues précédemment ont permis d’investiguer le spectre de liaison des BoNoV de génotype 2 par immunofluorescence indirecte sur des cultures cellulaires bovines d’origines tissulaires différentes. Les VLP ont été capables de se fixer sur chacune des lignées testées tandis que la fluorescence diminuait d’intensité après traitement des cellules par le periodate de sodium. Au cours d’une deuxième étude, les structures permettant l’attachement des BoNoV de génotype 2 ont été investiguées quantitativement en cytométrie en flux avec les VLP. Parmi les enzymes et substances utilisées pour traiter les cellules, le periodate de sodium, l’α-galactosidase, la trypsine, la chymotrypsine et la phospholipase C ont très significativement diminué l’intensité du signal tandis que la neuraminidase a également permis de le réduire modérément. Les sulfates d’héparane ou de chondroïtine n’étaient par contre pas impliqués. Une troisième étude, toujours réalisée en cytométrie en flux, a permis d’évaluer les voies d’internalisation des VLP. Au cours de cette étude, il a été montré que les voies liées aux radeaux lipidiques et de la macropinocytose étaient impliquées. Les trois études menées ont permis de montrer que la structure impliquée dans la liaison des BoNoV de génotype 2 est un saccharide présent sur de nombreux types cellulaires bovins ; que cette structure comprend un résidu α-galactose ; qu’un résidu acide neuraminique peut être aussi impliqué dans cette liaison ou peut la faciliter ; que les sulfates d’héparane et de chondroïtine ne le sont pas ; que des voies alternatives peuvent être utilisées pour l’internalisation de la VLP. Les différents résultats peuvent être intégrés dans le profil de risque zoonotique associé aux BoNoV. [less ▲]

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See detailSimulating the Holocene re-colonization of Europe by tree species using dynamic vegetation models
Dury, Marie ULg; Lehsten, Dörte; Dullinger, Stefan et al

Poster (2011, April)

At the beginning of the Holocene (10.000 BP) started a progressive re-colonization of Europe by temperate tree species from a limited number of glacial refugia. To reconstruct the speed, seemingly species ... [more ▼]

At the beginning of the Holocene (10.000 BP) started a progressive re-colonization of Europe by temperate tree species from a limited number of glacial refugia. To reconstruct the speed, seemingly species-specific, and the routes of the postglacial spread of European tree species, fossil records collected from various localities in Europe are invaluable. However, the relative roles of climatic fluctuations, dispersal capacities of individual species, and inter-specific competition in controlling the re-colonization rates remain controversial. We investigate these different aspects with two dynamic vegetation models (DVM), LPJ-GUESS and CARAIB. Transient runs of both models were performed over the Holocene, using HadCM3 GCM-reconstructed climate. Large-scale species migration at 0.5◦ x0.5◦ is represented in these models using migration rates derived from a small-scale cellular automaton, CATS. Individual tree species migration rates were pre-calculated with CATS every 1000 years over each grid cell used by the DVMs in the climatic conditions reconstructed by the GCM. In the DVMs, these migration speeds were influenced by the response to competition from other species, expressed as a function of net primary production ratios. The DVMs were used to study the migration of one species, from its 10.000 BP refugia, within a landscape defined by a set of other species for which no dispersal limitations are assumed. Here, we illustrate the results obtained for wind-dispersed tree species and compare them to their past distributions reconstructed from pollen and macrofossil data. [less ▲]

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See detailGold and silver nanomaterials based biosensors : a comparative study
Dreesen, Laurent ULg; Lismont, Marjorie ULg

Poster (2011, April)

Noble metal nanoparticles (NPs) are intensively studied due to their particular optical properties, mainly high optical absorption and diffusion yields, leading to interesting applications in biochemical ... [more ▼]

Noble metal nanoparticles (NPs) are intensively studied due to their particular optical properties, mainly high optical absorption and diffusion yields, leading to interesting applications in biochemical sensing, molecular tracking and imaging, drug delivery and photothermal therapies [1]. These unique optical properties arise from a physical process named surface plasmon resonance (SPR) which is a resonant coupling of incident light to the collective motion of electrons along the nanoparticles surface [2]. Optical SPR biosensors are able to measure complex formation in real time. Indeed, the SPR absorption spectrum band of the NPs is sensitive to the shape, size, inter-particle distance and composition of the NP as well as the dielectric properties of the surrounding medium [2]. Due to the sensitivity of SPR to the local dielectric environment, plasmonic NPs can thus act as transducers that convert small changes in the local refractive index or in the inter-particle distance into spectral shifts and broadenings of the absorption spectral bands [3]. Among metals, silver and gold NPs have received considerable interest for many reasons. For instance, they are stable in ambient atmosphere and exhibit good biocompatibility even if particular surface treatments are sometimes required. The Ag and Au NPs are also relatively easy to fabricate with different sizes and shapes allowing the tuning of the SPR optical absorption band from the near ultraviolet (400 nm) to the near infrared (1000 nm) wavelengths. In this study, our aim is to characterize two biosensors based on silver and gold spherical NPs in order to detect which one seems the best. Both NPs have a diameter close to 15 nm. We use the well-known biocytin-avidin complex as a model system because the bonding of avidin with biocytin is extremely strong with a dissociation constant three order of magnitude higher than the typical constants of antigen-antibody interactions. More precisely, we compare the intensities, the band shapes and the spectral locations of the SPR adsorption bands before and after the biomolecular recognition of avidin by biocytin molecules adsorbed on the Ag and Au NPs. The kinetic of the interaction is also discussed. Before surface treatment with biocytin, the NPs SPR bands are located around 390 and 520 nm for Ag and Au NPs, respectively. The SPR band intensity is higher for silver than for gold. Biocytin adsorption does not significantly modify the SPR spectral features. NPs do not therefore form aggregates and the local refraction index has not significantly changed. After avidin addition, a SPR red-shift and a broadening of the SPR bands are observed with both NPs as shown on Figure 1. These parameters evolved with time and reach their final values after around 45 min for each system. The aforementioned spectral changes arise from the biomolecular recognition process between biotin and avidin which leads to the NPs aggregation. The recognition process also induces a variation of the local refractive index around these NPs which contributes to the red-shift. The maximum SPR shifts are equal to 25 nm and 12 nm for silver NPs and gold NPs, respectively. Our results highlight the smaller dielectric sensitivity of gold NPs compared to the silver NPs one for a same particles’ size and for an equivalent concentration of avidin. The detection limit, described as the lowest concentration for clear identification of wavelength shift due to biomolecular recognition, is equal to 4 nM for both silver and gold NPs. With this protein concentration, 3 nm is the typical wavelength shift. The specificity of the biocytin - avidin biosensors is verified by replacing avidin by Bovine Serum Albumina (BSA). When BSA is added, we observe a SPR band shift which is smaller than the detection limit of 3 nm attesting the biosensor selectivity. Our work demonstrates the superiority of Ag over Au NPs for the elaboration of biosensors based on SPR. However, it is well-known that Ag NPs are less biocompatible than gold. This problem can be circumvented by an appropriate coating of the NPs surface prior ligand adsorption. [less ▲]

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