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

Conference (2009, June 13)

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 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 detailClean Development Mechanisms (CDM) and Sustainable Development in South Countries
Ozer, Pierre ULg

Conference (2009, June 13)

The Clean Development Mechanism (CDM) allows emission-reduction (or emission removal) projects in developing countries to earn Certified Emission Reduction (CER) credits, each equivalent to one tonne of ... [more ▼]

The Clean Development Mechanism (CDM) allows emission-reduction (or emission removal) projects in developing countries to earn Certified Emission Reduction (CER) credits, each equivalent to one tonne of CO2. These CERs can be traded and sold, and used by industrialized countries to a meet a part of their emission reduction targets under the Kyoto Protocol. The mechanism stimulates sustainable development and emission reductions, while giving industrialized countries some flexibility in how they meet their emission reduction limitation targets. Accepted projects must qualify through a rigorous and public registration and issuance process designed to ensure real, measurable and verifiable emission reductions that are additional to what would have occurred without the project. Between November 2004 and May 2009, the mechanism has registered 1653 projects and is anticipated to currently produce CERs amounting to 303 106 tonnes of CO2 equivalent yearly. The mechanism is extremely interesting since it is the first global, environmental investment and credit scheme of its kind, providing a standardized emissions offset instrument. However the geographical distribution of the CDM projects is revealing very large differences in between developing countries since China, India, Brazil and South-Korea totalise 82% of the CERs while Africa only represents 3,3% of the total. [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 detailDevelopment of a protocol for micropropagation of Jatropha curcas L
Medza Mve, Samson Daudet ULg; Mergeai, Guy ULg; Baudoin, Jean-Pierre ULg et al

in Fifth International Conference on Renewable Resources and Biorefineries (2009, June 11)

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 detailAgreement between raters and groups of raters
Vanbelle, Sophie ULg

Doctoral thesis (2009)

Agreement between raters on a categorical scale is not only a subject of scientific research but also a problem frequently encountered in practice. Whenever a new scale is developed to assess individuals ... [more ▼]

Agreement between raters on a categorical scale is not only a subject of scientific research but also a problem frequently encountered in practice. Whenever a new scale is developed to assess individuals or items in a certain context, inter-rater agreement is a prerequisite for the scale to be actually implemented in routine use. Cohen's kappa coeffcient is a landmark in the developments of rater agreement theory. This coeffcient, which operated a radical change in previously proposed indexes, opened a new field of research in the domain. In the first part of this work, after a brief review of agreement on a quantitative scale, the kappa-like family of agreement indexes is described in various instances: two raters, several raters, an isolated rater and a group of raters and two groups of raters. To quantify the agreement between two individual raters, Cohen's kappa coefficient (Cohen, 1960) and the intraclass kappa coefficient (Kraemer, 1979) are widely used for binary and nominal scales, while the weighted kappa coefficient (Cohen, 1968) is recommended for ordinal scales. An interpretation of the quadratic (Schuster, 2004) and the linear (Vanbelle and Albert, 2009c) weighting schemes is given. Cohen's kappa (Fleiss, 1971) and intraclass kappa (Landis and Koch, 1977c) coefficients were extended to the case where agreement is searched between several raters. Next, the kappa-like family of agreement coefficients is extended to the case of an isolated rater and a group of raters (Vanbelle and Albert, 2009a) and to the case of two groups of raters (Vanbelle and Albert, 2009b). These agreement coefficients are derived on a population-based model and reduce to the well-known Cohen's kappa coefficient in the case of two single raters. The proposed agreement indexes are also compared to existing methods, the consensus method and Schouten's agreement index (Schouten, 1982). The superiority of the new approach over the latter is shown. In the second part of the work, methods for hypothesis testing and data modeling are discussed. Firstly, the method proposed by Fleiss (1981) for comparing several independent agreement indexes is presented. Then, a bootstrap method initially developed by McKenzie et al. (1996) to compare two dependent agreement indexes, is extended to several dependent agreement indexes (Vanbelle and Albert, 2008). All these methods equally apply to the kappa coefficients introduced in the first part of the work. Next, regression methods for testing the effect of continuous and categorical covariates on the agreement between two or several raters are reviewed. This includes the weighted least-squares method allowing only for categorical covariates (Barnhart and Williamson, 2002) and a regression method based on two sets of generalized estimating equations. The latter method was developed for the intraclass kappa coefficient (Klar et al., 2000), Cohen's kappa coefficient (Williamson et al., 2000) and the weighted kappa coefficient (Gonin et al., 2000). Finally, a heuristic method, restricted to the case of independent observations, is presented (Lipsitz et al., 2001, 2003) which turns out to be equivalent to the generalized estimating equations approach. These regression methods are compared to the bootstrap method extended by Vanbelle and Albert (2008) but they were not generalized to agreement between a single rater and a group of raters nor between two groups of raters. [less ▲]

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See detailMaternal transfer of mercury to offspring in phocids
Habran, Sarah ULg; Pomeroy, Paddy; Debier, Cathy et al

Conference (2009, June 09)

Marine mammals may display high mercury (Hg) levels in their tissues, which raises the question of the importance of toxic metal transfer from mother to offspring. Indeed, Hg could be transferred from ... [more ▼]

Marine mammals may display high mercury (Hg) levels in their tissues, which raises the question of the importance of toxic metal transfer from mother to offspring. Indeed, Hg could be transferred from mothers to fetuses via the placenta and to suckling pups via the milk, potentially affecting them during their most sensitive periods of development. Some lactating female phocids fast during the suckling period. This fasting period involves not only an important mobilization of energy reserves, but also mobilization of potentially associated contaminants. We studied and compared maternal transfer of Hg to offspring in two phocid species: the northern elephant seal (Mirounga angustirostris) from the Californian coast and the grey seal (Halichoerus grypus) from the Isle of May in Scotland. Total mercury concentrations (THg) were measured in whole blood and maternal milk of 20 mother-pup pairs of each species in early and late lactation. Methylmercury (MeHg) levels were also measured in the blood and milk of grey seals. Results indicated that Hg passed from the maternal tissue into the phocid milk. Milk showed a range of THg levels from 15 to 60 ppb (ng.g-1-wet-weight). From the first days after birth, pups displayed relatively high blood Hg levels suggesting that a Hg transfer through placenta occurred. Blood Hg levels in mothers and pups also varied significantly throughout lactation. While maternal levels doubled, pup levels were reduced by half between the beginning and the end of lactation. Remobilization of proteins and lipids during fasting and milk production in mothers might lead to a release of Hg in blood and therefore increase the levels in late lactation. On the contrary, Hg would be progressively stored in pup organs during their development. Decreasing Hg levels in pups also suggest that the Hg intake via the milk might be lower than that via the placenta. This study highlights a transplacental and transmammary transfer of Hg in both phocid populations. However, further toxicology studies are needed to help understand the potential impact of this Hg transfer. Results also showed that physiological processes such as lactation and/or fasting can modify Hg levels in the blood of mothers and pups. Therefore, such processes and body condition should be considered carefully when interpreting Hg levels in the framework of biomonitoring. [less ▲]

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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 detailLa conscientisation de jeunes de l'ARVM par rapport aux faits génocidaires
Grandjean, Geoffrey ULg

Conference given outside the academic context (2009)

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See detailGestion à distance de la biologie délocalisée: expérience du CHU de Liège
Cavalier, Etienne ULg

Conference given outside the academic context (2009)

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See detailNew developments in the functionalization of aliphatic polyesters by "click" copper-catalyzed azide-alkyne cycloaddition
Lecomte, Philippe ULg; Riva, Raphaël ULg; Schmeits, Stephanie ULg et al

Conference (2009, June 03)

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any pendant functional group is a ... [more ▼]

Nowadays, biodegradable and biocompatible aliphatic polyesters are widely used as environmentally friendly thermoplastics and biomaterials. Nevertheless, the absence of any pendant functional group is a severe limitation for the development of novel applications. Our strategy aiming at functionalizing aliphatic polyesters relies on the “click” copper-catalyzed cycloaddition (CuAAC) of alkynes duly substituted by functional groups or even chains onto PCL bearing pendant azides. The aliphatic polyesters bearing pendant azides have been very efficiently synthesized by a straightforward approach, which relies on the ring-opening copolymerization of αClεCL (or γBrεCL) and εCL (or lactide) followed by reaction with sodium azide to convert pendant chlorides or bromides into azides. The alternative reported by Emrick et al. is based on the CuAAC reaction of azides substituted by any functional group onto copolyesters of poly(ε-caprolactone) bearing pendant alkynes. Interestingly enough, Emrick et al. carried out the CuAAc reaction in water at 80°C. Unfortunately, it turned out, at least in our hands, that these conditions can not be extended to the derivatization of more sensitive aliphatic polyesters because degradation was then unavoidable. Nevertheless, we found out that degradation can be minimized whenever the CuAAC reaction is carried out in an organic solvent at lower temperature. Typically, the CuAAC reaction was carried out in DMF or THF at 35°C. Recently, it was shown that supercritical carbon dioxide can be used as a more environmentally friendly solvent than DMF or THF. The contamination by catalytic residues of aliphatic polyesters functionalized by the CuAAC reaction is a severe limitation in view of future applications, especially in the biomedical field. In the last part of this talk, a special attention will be paid on our current efforts to get rid of copper residues. [less ▲]

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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 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 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 ▲]

Detailed reference viewed: 71 (2 ULg)