Seasonal and inter-annual variations of community metabolism rates of a Posidonia oceanica seagrass meadow

Poster (2012, April 22)

New alginate-chitosan hydrogel to repair cartilage. A partner ship between www.bcru.be and www.kitozyme.com

Poster (2012, April 19)

Influence of protein context on the propensity of polyglutamine tracts to induce protein aggregation into amyloid fibrils

Poster (2012, April 18)

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

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

Possible intracellular effect of the new water-soluble form of curcumin (NDS27) on the oxidant response of stimulated neutrophils

Poster (2012, April 18)

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) to kill pathologic agents. But, an excessive ROS production, called “oxidative ... [more ▼]

Neutrophils (PMNs) are involved in host defense against infections through the production of reactive oxygen species (ROS) to kill pathologic agents. But, an excessive ROS production, called “oxidative stress” is associated with tissue damages and development of chronic or acute inflammatory diseases. PMNs are prime therapeutic targets to control inflammatory events associated to ROS production. Nowadays, there is a growing interest for the use of polyphenolic molecules to modulate the inflammatory response. The aim of this work was to study the antioxidant effect of NDS27 (1), a new highly water-soluble form of the polyphenolic molecule curcumin, on in vitro stimulated equine PMNs. NDS27 (10-6 to 10-4 M) was pre-incubated with cells and eliminated before their activation. The ability of NDS27 to enter into the cells was checked by HPLC from the cellular extracts. The intracellular ROS production by phorbol myristate acetate (PMA) stimulated PMNs was measured by fluorescence using 2’,7’-dichlorofluorescin diacetate. Lucigenin dependent chemiluminescence was used to measure extracellular ROS production. Additionally, the effect of NDS27 was tested on the activity of myeloperoxidase (MPO), a hemic enzyme contributing to the oxidant response of neutrophils. The activity of the released MPO by cytochalazine B (CB) and N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulated PMNs was measured by SIEFED (“Specific Immunologic Extraction Followed by Enzymatic Detection”) (2). The HPLC results showed that NDS27 enters into PMNs and interacts with their membrane. NDS27 significantly and dose-dependently inhibited the ROS production in neutrophils without affecting their viability. Likewise, the activity of MPO released by PMNs was lowered by NDS27. Overall, our findings demonstrate that the membrane of neutrophils is permeable to NDS27 or interacts with the drug, suggesting that its inhibitory effect on ROS production is mainly associated to an intracellular effect probably by acting on the enzymes implied in respiratory burst like NADPH oxidase and MPO. The modulatory effect of NDS27 towards the oxidant activity of cells involved in immune and inflammatory response open therapeutic perspectives to control equine or human pathologies with excessive inflammatory reactions. 1. Neven et al. 2011, Patent Application Publication: US2011/0257126 A1 2. Serteyn et al. 2005, European Patent Specification : EP1711817 B1 [less ▲]

Molecular biomimetics applied to medical devices

Poster (2012, April 18)

New Advances for In Situ Protein Identification by MALDI In-Source Decay FTMS Imaging

Poster (2012, April 18)

MALDI imaging mass spectrometry has proven to be effective for the discovery and the monitoring of disease-related proteins. With this technique a molecular analysis could be performed directly from ... [more ▼]

MALDI imaging mass spectrometry has proven to be effective for the discovery and the monitoring of disease-related proteins. With this technique a molecular analysis could be performed directly from tissue sections in the region of the diseased area. The use of in-source decay (ISD), allowing fast and reliable sequences assignments of proteins termini, has proven to be a crucial tool for proteins identification in solution and tissue slices. However, it is necessary to develop additional tools that allow unambiguous assignment of proteins sequences in complex tissue slices. The development of bioinformatic tools and the use of ultra-high mass resolution and high mass accuracy of Fourier transform ion-cyclotron (FTICR) mass spectrometry are ideal for this purpose. In this study, we show that FTICR mass spectrometry combined with data filtering with a software that subtracts matrix peaks aid protein identification. All measurements were carried out on a SolariX FTMS (9.4 Tesla) equipped with a Dual Source with a smartbeamTMII laser (Bruker Daltonics). Mouse brain tissue slices of 14 µm thickness were rinsed to obtain optimal sensitivity and high-quality ions. Before matrix application, a spot of myelin was deposited near mouse brain. 1,5-Diaminionaphtalene was sprayed using an ImagePrep (Bruker Daltonics). Results were interpreted using BioToolsTM 3.2 in combination with MascotTM (Matrix Science) for ISD spectra and FlexImagingTM 3.0 for MALDI-ISD imaging experiments. Matrix peaks were subtracted using an in-house written Java code that sequentially scans all peak lists from acquired spectra against the DAN mass list. Then, another Java code allows to create 2D ion images at selected m/z ratios. The studies were carried out by MALDI-ISD imaging to create interest on FTICR mass spectrometer for proteins identification in the field of biomarkers characterization. It is demonstrated that protein ISD leads to the same pattern of fragmentation observed during MALDI-TOF analyzes. Fragmentation generates cn- and zn-series ions of myelin in presence of DAN. The internal calibration of all the data provides a mass accuracy neighboring 2.5 ppm over the m/z range of interest (300-2500 Da) and a mass resolution of 70000 at m/z 400 Da. It allows the assignment of ISD fragments of proteins in the low mass range (m/z between 300 and 900) that is unambiguously validated by the “ISD signal” recorded from the spots of pure protein solution (myelin) near tissue slice. Moreover, the use of our software “cleans” MS imaging data by reducing/eliminating MALDI matrix peaks that are isobaric to an analyte peak. Novel aspect This study evidences the main input of FTICR mass spectrometer for pathologies diagnosis based on biomarkers localization and identification by MALDI-ISD imaging. [less ▲]

Hemocompatibility of nanocarriers designed to transport biopharmaceutical drugs

Poster (2012, April 18)

The optimization of nanoparticles (NP) for drug delivery, in particular to target the BBB, imposes to verify their hemocompatibility both for toxicological and efficiency of targeting perspectives. Indeed ... [more ▼]

The optimization of nanoparticles (NP) for drug delivery, in particular to target the BBB, imposes to verify their hemocompatibility both for toxicological and efficiency of targeting perspectives. Indeed the large surface they are able to expose to the biological environment promotes their interaction with various biochemicals, in particular proteins which can after adsorption elicit the activation of biological cascades either responsible from NP clearance or/and harmful body reaction (inflammatory / coagulation). In the frame of the European Integrated Project : “Nanobiopharmaceutics”, we have the opportunity to compare the hemoreactivity of about 145 different NP samples differing in core and surface chemistry and classified according to their expected difference in hydrophobicity based on the nature of their core materials. According to this classification, PLGA nanoparticles, polyglycidol-polyethyethylene oxide nanoparticles, polyglycidol thyolated or polyacrylamide nanogels, and polyelectrolyte complexes either based on polyamidoamine or poly(N,N-dimethylamino-2-ethylmethacrylate) have been evaluated within a concentration ranging from 0.3 to 1000 =g/mL. These in vitro tests have been realized for screening purpose adopting normal human bloods and according to Iso 10993. As a summary of this extensive study, our results clearly highlight that most of the polymeric nanoparticles evaluated give rise to some alterations of the blood components. In particular the platelets, intrinsic pathway of coagulation and complement activation are the most reactive biological parameters in the presence of these nanostuctures. Although not strictly related to the surface chemistry our classification has also allowed us to derive some clear correlations between nanomaterial properties and their hemoreactivity. Within the class of polyelectrolyte electrolyte complexes, the modifications brought in the surface chemistry has drastically improved their hemoreactivity. [less ▲]

Children of lesbian parents: Research on family triadic interactions

Poster (2012, April 18)

Optimisation of new biodegradable microcarriers tailored for tissue engineering

Poster (2012, April 18)

Synthesis and evaluation of boronic acids as inhibitors of Penicillin Binding Proteins of classes A, B and C

Poster (2012, April 18)

The widespread use of beta-lactam antibiotics has lead to the worldwide appearance of drug-resistant strains. Bacteria have developed resistance to beta-lactams by three main mechanisms: the production of ... [more ▼]

The widespread use of beta-lactam antibiotics has lead to the worldwide appearance of drug-resistant strains. Bacteria have developed resistance to beta-lactams by three main mechanisms: the production of beta-lactamases that catalyze hydrolysis of beta-lactams, the production of low-affinity, drug resistant Penicillin Binding Proteins (PBPs) and the over expression of resistant PBPs. PBPs are interesting targets because they catalyse the last steps of the biosynthesis of peptidoglycan, which is unique in bacteria and has no mammalian analogs, outside the cytoplasmic membrane. Various non-ß-lactam inhibitors of PBPs have been developed with the objective of attempting to stall the development of ß-lactam resistance. Boronic acids are potent beta-lactamase inhibitors and have been shown to display some specificity for soluble transpeptidases and PBPs, but their potential as inhibitors of the latter enzymes is yet to be widely explored. Recently, a (2, 6-dimethoxybenzamido)methylboronic acid was identified as being a potent inhibitor of Actinomadura sp. R39 transpeptidase (IC50: 1.3 µM). Here, we will discuss the synthesis of a number of acylaminomethylboronic acids, analogs of (2, 6-dimethoxybenzamido)methylboronic acid, and their potential as inhibitors of PBPs. Several boronic acids of this library were able to inhibit PBPs of classes A, B and C from penicillin sensitive strains. Thus (2-nitrobenzamido)methylboronic acid was identified as a good inhibitor of class A PBP (PBP1b from S. pneumoniae, IC50 = 26 µM), class B PBP (PBP2xR6 from S. pneumoniae, IC50 = 138 µM) and class C PBP (R39 from Actinomadura sp., IC50 = 0.6 µM). Crystal structures of complexes of R39 and PBP1b with boronic acid analogs of our library have already been solved and allowed an interpretation of results. We believe that this work opens new avenues towards the development of molecules that will inhibit PBPs, and eventually display bactericidal effect, on distinct bacterial species. [less ▲]

Pierres à aiguiser en Gaule Belgique et en Germanie : mise en place d'une typologie et identification des matériaux

Poster (2012, April 04)

MicroRNA-146a is a causative factor and a specific biomarker for peripartum cardiomyopathy

Poster (2012, April)

The Venus nitric oxide nightglow vertical distribution : update, new features and modelling

Poster (2012, April)

Ultraviolet (UV) spectra of the delta (190-240 nm) and gamma (225-270 nm) bands of the nitric oxide (NO) molecule have been measured in the atmosphere of the Venus night side with the Spectroscopy for ... [more ▼]

Ultraviolet (UV) spectra of the delta (190-240 nm) and gamma (225-270 nm) bands of the nitric oxide (NO) molecule have been measured in the atmosphere of the Venus night side with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express (VEX). Excited NO molecules on the night side of the planet find their source in the radiative recombinaison of O(3P) and N(4S) atoms produced on the dayside by Extreme Ultraviolet (EUV) solar photons that cause photodissociation of CO2 and N2 molecules. We analyse with an improved statistics the behaviour of the vertical emission profile of the NO nightglow. We also present a method used to retrieve and analyse the volume emission rate. We describe the dependence of the vertical distribution with latitude and local time and its variability. New features in the vertical distribution of the NO emission such as double peaks are also exhibited. Furthermore, we use a one-dimensional chemical-diffusive model to compare the major features of the calculated O2 1.27 microm and NO UV emissions profiles with those observed with SPICAV. [less ▲]

Calcium-induced conformational changes of the elicitor and membrane-active fengycin

Poster (2012, April)

Fengycin is a natural lipopeptide synthetized by Bacillus subtilis strains. It is characterized by strong antifungal and low hemolytic activities. It seems also play a role in the promoting of elicitor ... [more ▼]

Fengycin is a natural lipopeptide synthetized by Bacillus subtilis strains. It is characterized by strong antifungal and low hemolytic activities. It seems also play a role in the promoting of elicitor activities of other compounds. The target of the biological activities of fengycin is supposed to be plasma membrane of sensitive cells. Even though the natural fengycin from has been discovered 25 years ago, nowadays, there is an increase of interest for this compound because of its potent applications. Until 15 years ago, the primary structure of fengycin was a matter of open debate before the publication of the corrected structure obtained by nuclear magnetic resonance and mass spectroscopy techniques. Although the infrared and ultraviolet absorption spectra of the lipopeptide were measured, no detailed analysis of these data was performed probably because of the unconventional sequence of the lipopeptide making these kinds of analyses complicated. In this work, our attempt was to analyze the conformational properties of fengycin as well as the calcium-induced changes using two complementary spectroscopic methods, Fourrier transformed infrared spectroscopy (FTIR) and circular dichroism (CD). In a first step, we have characterized the conformational properties of pure fengycin. The lipopeptide adopts turn conformation in trifluoroethanol, a membrane-mimicking solvent. D-aminoacids seem to be involved in intra molecular hydrogen bonds. In a second step, we have investigated the role played by Ca2+ ions on the possible conformational changes of fengycin. The addition of calcium gives rise to important modifications of the conformation. As fengycin has two glutamate residues, calcium is supposed to bind to their side chains. In conclusion, we have demonstrated that the conformation of fengycin is closely depending of the environment and the presence of calcium ions play an important role on the conformational changes of the lipopeptide. Moreover, spectra obtained both FTIR and CD methods ascertain the presence of turn conformation. [less ▲]

he influence of transformational leadership on commitment: New underlying processes

Poster (2012, April)

Timbre description of the sound of air-treatment systems for predicting acoustic confort

Poster (2012, April)

- A refined model of Quaternary valley downcutting emphasizing the interplay between tectonically triggered regressive erosion and climatic cyclicity

Poster (2012, April)

Shaft sealing issue in CO2 storage sites

Poster (2012, April)

Magnetic hybrid materials for triggered drug delivery and optical properties of intraocular lens

Poster (2012, March 30)

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such ... [more ▼]

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such as temperature, pH, ionic strength, magnetic field, etc. Nanohybrids bearing an inorganic core and thermo-responsive polymer shell are particularly applicable in target delivery and controlled drug release. Poly (N-vinylcaprolactam) (PNVCL) and its copolymers, exhibiting lower critical solution temperature (LCST) where the transition between hydrophilic and hydrophobic state happens, is one of the optimal choices for this core/shell structure. Here we present the in-situ fabrication of thermo-responsive gold nanohybrids coated with a novel poly (vinyl alcohol)-b-poly (N-vinylcaprolactam) (PVOH-b-PNVCL) block copolymers, which were prepared by the cobalt-mediated radical polymerization (CMRP). The interaction between both PVOH and PNVCL segments and gold nanoparticles was confirmed by FT-IR spectra. A sharp thermo-induced phase transition with a good reversibility upon change in temperature was detected by DLS and UV/vis spectrometer. Furthermore, the presence of hydrophilic PVOH moieties endows the gold nanohybrids with improved colloidal stability above LCST without any flocculation detected. This kind of gold nanohybrids can be envisaged as a new drug delivery vehicle. [less ▲]

1D many-body quantum transport of Bose-Einstein condensates : a truncated Wigner approach

Poster (2012, March 29)

We calculate the transport properties of an ultracold gas of Bose- Einstein condensed atoms that is coupled from a magnetic trap into a one-dimensional waveguide. A central aim of such guided atom lasers ... [more ▼]

We calculate the transport properties of an ultracold gas of Bose- Einstein condensed atoms that is coupled from a magnetic trap into a one-dimensional waveguide. A central aim of such guided atom lasers is to study the role of atom-atom interaction in many-body transport processes across finite scattering regions within the waveguide resembling tunnel junctions and quantum dots. Our numerical approach to solve this many-body scattering problem is based on a home-made theory where the boundaries of the system are simulating an open system enabling us to calulate observable in the steady-state regime such as density, current, transmission. The results are compared to the mean-field regime. [less ▲]

Microstructure characterisation of nanocomposite polymeric foams by X-ray microtomography

Poster (2012, March 26)

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon ... [more ▼]

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon nanotubes inside a polymer matrix shows exceptional electromagnetic interference shielding effectiveness when foamed. However, the effective properties of such materials strongly depend on the shape and topology of the microstructural cells. An accurate method for investigating the cellular microstructure is X-ray microtomography (XRμT), for it is non-destructive, and it provides 3D geometric information. Although it cannot be used to observe nanofiller dispersion, it has a strong potential for cell structure characterisation. In order to reduce the need for trial and error in tailoring these materials, our objective is to quantify, using XRμT, cellular microstructure, for two different types of foaming procedures, namely supercritical CO2 batch foaming and freeze drying, to be able to establish a link between the structure and its shielding effectiveness. The main difficulty stems from the type of material being studied: it is light, therefore hardly absorbs X-rays, cell size is small compared to the resolution capacity of the tomograph, and cell wall thickness is extremely thin in some cases, making them very hard to discern in the images. For these reasons, common image analysis tools for identifying and delimiting objects in an image prove impractical. We propose an original method that uses the 3D autocorrelation function of the tomograms to determine statistical information from these images, such as average cell size and anisotropy, without the need to binarise and segment the images. [less ▲]

Impact of the alkyl chain carbon atom number of uronic acid-derivative surfactants on interfacial and colloidal systems

Poster (2012, March 26)

Uronic acid-derivative surfactants represent today an attractive group of Carbohydrate-based amphiphilic compounds for both fundamental and practical reasons [1,2]. In the continuity of our screening of ... [more ▼]

Uronic acid-derivative surfactants represent today an attractive group of Carbohydrate-based amphiphilic compounds for both fundamental and practical reasons [1,2]. In the continuity of our screening of their basic properties, and the approach in establishing relationships between their structure and properties [3,4], the impact of the alkyl chain carbon atom number on interfacial and colloidal systems has been systematically investigated. In this communication, the effect of odd-even number of carbon atom from C11 to C18, and the particular behavior of long chain derivatives on interfacial properties, as well as their impact on the formation and stability of colloidal systems, are presented. Experimental approaches have been conducted by investigating their properties and behaviors at gas-liquid and liquid-liquid under dynamic, equilibrium, and oscillatory interfacial conditions. Results are completed by and discussed with single molecule models established by theoretical approaches. [1] Razafindralambo, H.;Blecker, C.; Paquot, M., Screening of Basic Properties of Amphiphilic Molecular Structures for Colloidal System Formation and Stability. In Amphiphiles: Molecular Assembly and Applications, American Chemical Society: 2011; Vol. 1070, pp 53-66. [2] Laurent, P.; Razafindralambo, H.; Wathelet, B.; Blecker, C.; Wathelet, J.; Paquot, M., Synthesis and Surface-Active Properties of Uronic Amide Derivatives, Surfactants from Renewable Organic Raw Materials. J. Surfactants Deterg. 2011, 14, 51-63. [3] Razafindralambo, H.; Richel, A.; Wathelet, B.; Blecker, C.; Wathelet, J.; Brasseur, R.; Lins, L.; Miñones, J.; Paquot, M., Monolayer properties of uronic acid bicatenary derivatives at the air-water interface: effect of hydroxyl group stereochemistry evidenced by experimental and computational approaches. Physical chemistry chemical physics: PCCP 2011, 13 15291-15298. [4] Razafindralambo, H.; Blecker, C.; Mezdour, S.; Deroanne, C.; Crowet, J.; Brasseur,R.; Lins, L.; Paquot, M., Impacts of the Carbonyl Group Location of Ester Bond on Interfacial Properties of Sugar-Based Surfactants: Experimental and Computational Evidences. The journal of physical chemistry. B 2009, 113, 8872-8877. [less ▲]

Adsorption kinetics of total proteose peptone fractions at the air-water and n-dodecane-water interface

Poster (2012, March 26)

Surface properties of whey proteins are essential in applications requiring oil emulsification in an aqueous phase, or foam structure formation [1]. The adsorption at interfaces constitutes then an ... [more ▼]

Surface properties of whey proteins are essential in applications requiring oil emulsification in an aqueous phase, or foam structure formation [1]. The adsorption at interfaces constitutes then an approach of the physico-chemical mechanisms of foaming and emulsifying properties. Proteose-peptone is the minor fraction of whey's protein, thermoresistant and acid-soluble protein fraction extracted from milk [2], and known for its interesting surface properties [3]. In this study, the TPP fractions were extracted from skimmed milk UHT (milk TPP) and whey protein concentrate (WPC TPP). Their adsorption kinetics at the air-water and n-dodecane-water interfaces was investigated by the drop volume tensiometer method. Protein solutions of 1% (w/v) were <br />characterized under dynamic condition at various pH (4.0; native pH 4.67- 4.70 and 7.0). Milk TPP showed the lowest values as well as a faster reduction in surface tension at both considered interfaces. Therefore, TPP were found to e effective as surfactants. These results let us to presage good emulsifying and foaming properties of milk TPP compared to WPC TPP. The considerable influence of pH and extraction source on proteose-peptone's interfacial property have been highlighted. [less ▲]

Environmental product declarations of mineral paving, a tool for sustainable product choices

Poster (2012, March 22)

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental ... [more ▼]

This study performs the environmental product declarations for three Belgian mineral products, two granite and one sandstone paving. Both main goals of this work were to obtain Belgian environmental product declarations to strengthen existing databases and to get similar information for their Asian counterparts. Indeed, competition with China for bluestone products and with India for sandstone pavement is very important due to very competitive prices despite their foreign origin and possibly higher induced environmental impacts. [less ▲]

Constraints on the Parental Melts of Enriched Shergottites from Image Analysis and High Pressure Experiments

Poster (2012, March 20)

Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element ... [more ▼]

Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element concentrations and initial 87Sr/86Sr and lower initial 143Nd/144Nd and 176Hf/177Hf than depleted shergottites. It is now generally admitted that shergottites result from the melting of at least two distinct mantle reservoirs. Some of the olivine-phyric shergottites (either depleted or enriched), the most magnesian Martian basalts, could represent primitive melts, which are of considerable interest to constrain mantle sources. Two depleted olivine-phyric shergottites, Yamato 980459 and Nothwest Africa (NWA) 5789, are in equilibrium with their most magnesian olivine and their bulk rock compositions are inferred to represent primitive melts. Larkman Nunatak 06319 and NWA 1068, the most magnesian enriched basalts, have bulk Mg# that are too high to be in equilibrium with their olivine megacryst cores. Parental melt compositions have been estimated by subtracting the most magnesian olivine from the bulk rock composition, assuming that olivine megacrysts have partially accumulated. However, because this technique does not account for the actual petrography of these meteorites, we used image analysis to study these rocks history, reconstruct their parent magma and understand the nature of oli-vine megacrysts. Our image analysis results are supported by a series of high-pressure experiments performed on LAR 06319 bulk rock composition to test if it could represent a primitive melt, and understand its crystallization history. [less ▲]

Déficits de mémoire verbale à court-terme pour l’ordre sériel chez des enfants dyslexiques

Poster (2012, March 16)

Application of mixed polygenic model to control for cryptic/genuine relatedness and population stratification.

Poster (2012, March 12)

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several ... [more ▼]

In genome-wide association studies (GWAs), population stratification may cause inflated type I errors and overly-optimistic test results, when not properly corrected for. During the past decade, several methods have been proposed for association testing in the presence of population stratification. Among these, principal components-based approaches are the most popular. Principal component analysis (PCA) allows data transformation to a new coordinate system such that the projection of the data along the first new coordinate (called the PC1) has the largest variance; the second PC has the second largest variance, and so on. In practice, two components are usually enough to adjust or to control for population stratification. They can easily be included in parametric association models as covariates. Despite the success of this strategy, there are still some caveats which need further attention. Among these are that principal component-based methods generally do not account for cryptic relatedness (kinship) between supposedly unrelated individuals, are not straightforwardly adapted to accommodate family-based designs or mixtures of families and unrelated individuals, and do not always take proper account of the trait under investigation. In this work, we present an easy-to-use alternative that addresses the aforementioned issues. For quantitative traits, we propose to first use the mixed polygenic model (possibly taking into account important non-genetic confounders as covariates), second to derive “polygenic” residuals from this model – hereby removing genomic kinship relationships, and third to consider these residuals as new traits in a classical genome-wide QTL analysis for “unrelated individuals”. The polygenic component of the aforementioned mixed polygenic model describes the contribution from multiple independently segregating genes, all having a small additive effect on the trait under investigation. Via an extensive simulation study, with various settings of population stratification and admixture, we show that this approach not only removes most of the “relatedness” between individuals (cryptic relatedness or known relatedness), but also removes most of the remaining substructures caused by population stratification or admixture. As a proof of concept, we demonstrate the efficiency of this robust method to control for population stratification on real-life genome-scale data from the SNP Health Association Resource (SHARe) Asthma Resource project (SHARP) (dbGaP accession number phs000166.v2.p1). We also provide leads to extend this method to dichotomous traits. [less ▲]

Evolution des dépenses alimentaires en produits d'origine animale des ménages wallons

Poster (2012, March 07)

Harmonized Growth Models and Simulations of the Evolution of Pure Stands of Norway spruce, Larches and Douglas-fir for Southern Belgium (Wallonia).

Poster (2012, March 02)

In order to compare different silvicultural scenarios we have undertaken the development of a software that can simulate stand evolution in regards to their species composition, site characteristics and ... [more ▼]

In order to compare different silvicultural scenarios we have undertaken the development of a software that can simulate stand evolution in regards to their species composition, site characteristics and silvicultural operations. As a first approach we limited the scope of our work to even-aged and pure coniferous stands of the three most important coniferous species in Wallonia (southern part of Belgium): Norway spruce (Picea abies), douglas-fir (Pseudotsuga menziensii) and larches (Larix sp.). This presentation introduces carried out simulations and compare their outcomes. First we gathered data sets from the permanent regional inventory, from observation networks and experimental plots throughout Wallonia. Then we adjusted, for these species, harmonized and distance-independent models of dominant-height growth, tree diameter growth, mortality, and the distribution of tree diameter frequency before the first thinning. Next we implemented those models in the Capsis platform, and we simulated, for the three species, the evolution of virtual stands using different scenarios. On one hand the evolution was performed without thinning, and on the other hand we applied silvicultural scenarios that are commonly used in Wallonia. As a result these models highlight, for example, the great juvenile growth and sensibility to stands density of larches whereas Norway spruce behaves the opposite. Further work is however needed to predict and simulate wood quality and value. Once this will be achieved we will attempt to optimize silvicultural scenarios for the three species. [less ▲]

Recent disturbances in the Congo Basin : an anthracological contribution to vegetation reconstructions

Poster (2012, March 01)

In contrast to the well-known vegetation history of the northern hemisphere, few is known about past vegetation change in Central Africa. However, recent palaeoecological and biogeographical studies ... [more ▼]

In contrast to the well-known vegetation history of the northern hemisphere, few is known about past vegetation change in Central Africa. However, recent palaeoecological and biogeographical studies suggest that early human disturbances had a substantial influence on Central Africa vegetation patterns, particularly allowing the expansion of light-demanding species. This interesting hypothesis is the basis of one of the main research questions of the ERA-net BIODIVERSA CoForChange project: what was and is the relationship between (increasing) human activity and vegetation change? A recently developed protocol for the identification of ancient Central African charcoal fragments opened the door for vegetation reconstructions with a high spatial and taxonomical resolution. Therefore, we chose to study macro-charcoals from pedoanthracological profiles situated in N Congo and SE Camero0n. In total, 48 taxa were found in nine radiocarbon dated profiles. At the moment, three taxa have been identified down to species level. First, we found numerous fragments of Gilbertiodendron dewevrei under a current monodominant forest of G. dewevrei (40 cm depth, 1421-1327 cal. BP). This seems to confirm the presumption that monodominant forests of G. dewevrei, shade-bearer species, are relatively stable. Second, we evidenced the lack of Triplochiton scleroxylon charcoals under a T. scleroxylon stand, which could confirm the hypothesis of the recent nature of those stands. Finally, our results suggest that taxonomic diversity of charcoal findings in open canopy Marantaceae forests is greater than in dense forests. Pterocarpus soyauxii and Millettia drastica have been found under an open Marantaceae forest at 40 cm depth (1184-1055 cal. BP). The abundance of the light-demanding species P. soyauxii appears to be decreasing over time (levels 20 to 40 cm depth) to the benefit of giant herbs. Anthracology in Central Africa is on the rise and the first results of the CoForChange project are promising. More identifications will follow, resulting in a better understanding of the evolution of Central African forests. [less ▲]

INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER INFLUENCE OF STEAM EXPLOSION ON CRYSTALLINITY PROPERTIES OF PURE CELLULOSE FIBER

Poster (2012, March 01)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity [less ▲]

SMALL SAMPLE SIZE CAPABILITY INDEX FOR ASSESSING VALIDITY OF ANALYTICAL METHODS

Poster (2012, March)

Analytical method’s capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability ... [more ▼]

Analytical method’s capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices has to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work, an improved capability index, namely Cpk-tol and the corresponding estimator of proportion of non conforming results (tolCpk−π) is proposed. Through Monte-Carlo simulations, they have been shown to greatly increase the estimation of analytical methods capability in particular in low sample size situations as encountered during methods validation or transfer. Additionally, the usefulness of this capability index is illustrated through several case studies. [less ▲]

Evaluating COSMO’s lake module (FLake) for an East-African lake using a comprehensive set of lake temperature profiles

Poster (2012, March)

Analysis of tobacco mainstream smoke by GC×GC TOFMS

Poster (2012, March)

Pilot Trial of STAR in Medical ICU

Poster (2012, March)

AN INNOVATIVE APPROACH TO SELECT THE PREDICTION MODEL IN THE DEVELOPMENT OF NIR SPECTROSCOPIC METHODS

Poster (2012, March)

Taking into account its non-invasive, non-destructive character and fast data acquisition, near infrared spectroscopy is more and more integrated in production processes to acquire analytical results ... [more ▼]

Taking into account its non-invasive, non-destructive character and fast data acquisition, near infrared spectroscopy is more and more integrated in production processes to acquire analytical results. Implementation of a NIR quantitative method is performed using an iterative heuristic approach that will ultimately build a model allowing the prediction of the concentration of the analyte of interest. In this context, the aim of the present study was to develop an innovative approach based on statistical tolerance intervals and the desirability index FMI (Fitting Model Index) to select the most appropriate prediction model from a list of candidate models instead of using conventional criteria such as R², RMSEC, RMSECV and RMSEP [1-2] without objective decision rules. This new approach is illustrated on different steps of a real pharmaceutical manufacturing process: water and Active Pharmaceutical Ingredient (API) determinations in pharmaceutical pellets. Variability sources such as production campaigns, batches, days and operators were introduced in the calibration and validation sets. Partial Least Square (PLS) regression on the calibration sets was performed to build prediction models of which the ability to quantify accurately was tested with the validation sets. Regarding the product specifications, the acceptance limits were set at 20% and 5%, for the moisture and API determination, respectively.As can be seen from Figure 1 and 2, this innovative approach based on the desirability index FMI of the accuracy profile enabled to build and select the most appropriate prediction model in full accordance with its very final goal, to quantify as accurately as possible the analytes of interest. [1] Hubert Ph. et al., J. Pharm. Biomed. Anal., 36, 2007, 579-586. [2] Rozet E. et al., Ana. Chim. Acta, 591, 2007, 239-247. [less ▲]

Protocol 3 : Belgian innovative projetcs to help community dwelling frail elderly

Poster (2012, March)

Biofuel by-product for poultry diets

Poster (2012, February 28)

Reconstruction of the long-term satellite-derived sea surface temperature in the South China Sea

Poster (2012, February 24)

The AVHRR (Advanced Very High Resolution Radiometer) sea surface temperature is very useful for researches in oceanography because of its high resolution. An AVHRR limitation is the high missing data ... [more ▼]

The AVHRR (Advanced Very High Resolution Radiometer) sea surface temperature is very useful for researches in oceanography because of its high resolution. An AVHRR limitation is the high missing data percentage due to cloud coverage. In the South China Sea, the average missing data is usually more than 80%, especially more than 95% in the region near the Borneo Island. In this study, we use DINEOF tool to reconstruct a daily night-time AVHRR data set with horizontal resolution of 4km spanning from 1989 to 2009. Besides, a comparison between the results and in situ data is shown. The EOF analysis shows that the first three modes explain about 95% of seasonal variability. [less ▲]

Theoretical investigation of the electronic dynamics induced by short pulses and study of the ionization of ABCU in strong fields

Poster (2012, February 15)

Voluntary feed intake of tropical forage legumes hays by growing pig in Western Democratic Republic of Congo

Poster (2012, February 12)

Implication of honeydew microflora in ant-aphid mutualism

Poster (2012, February 10)

Some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection. From a behavioral point of ... [more ▼]

Some ant and aphid species can present a mutualistic relationship, ants using aphid honeydew as sugar source and in exchange providing the aphid colony cleaning and protection. From a behavioral point of view, this phe-nomenon has been well studied from decades. However, its chemistry and semiochemical mechanisms are still largely unknown. This study aims to identify semiochemicals involved in the establishment of this relation, using both chemical and behavioral approaches. Bioassays revealed that the great-est part of ant attraction toward aphid colonies is due to honeydew volatile compounds; enabling ant scouts to find more quickly aphid colonies and distantly recognize myrmecophilous species. Many of those VOCs seeming to have microbial origins, the main honeydew microorganisms have been isolated and their roles in VOCs production and ant attraction have been investigated. It appeared that honeydew microflora holds a key role in the establishment of ant-aphids mutualistic relationship. [less ▲]

Influence of reducing agent on microbial fermentation characteristics using an in vitro gas production method

Poster (2012, February 10)

Lipase-catalyzed synthesis of fatty acid sugar esters in pure ionic liquids and optimization by response surface methodology

Poster (2012, February 10)

Hymenoptera community of pig carcasse in an urban biotope

Poster (2012, February 10)

Most reports published in the field of forensic entomology studies are focused on Diptera pattern colonization and are neglecting Hymenoptera succession. Hymenoptera are part of the entomofaunal ... [more ▼]

Most reports published in the field of forensic entomology studies are focused on Diptera pattern colonization and are neglecting Hymenoptera succession. Hymenoptera are part of the entomofaunal colonization of a dead body as parasitoids of fly pupae. However, one should consider Hymenoptera parasitoids in a forensic entomology context to evaluate the time of death. Blowflies parasitoids may indeed be of particular importance as their time of attack is often restricted to a small, well-defined window of developmental time of the insect host. Because these parasitoids also interfere with developmental times of colonizing Diptera, a better understanding of their ecology is needed. [less ▲]

Identification of bacterial endosymbionts present in Pentalonia nigronervosa Coq. strains

Poster (2012, February 10)

Integration of external information into genetic evaluations by a Bayesian procedure

Poster (2012, February 10)

One of the most important theoretical assumptions of methods used to assess genetic values is that all available information has to be considered simultaneously to obtain unbiased estimates. However, the ... [more ▼]

One of the most important theoretical assumptions of methods used to assess genetic values is that all available information has to be considered simultaneously to obtain unbiased estimates. However, the widespread international exchange of genetic material and, more recently, the important development of the genomic selection lead to the coexistence of different genetic evaluations. Therefore, the blending of the different sources of information is necessary to achieve better prediction. Integration of external information into genetic evaluations by a Bayesian procedure can partially resolve the problem under some assumptions. Results from such a method that also avoids double counting among external animals are highly similar to those from a joint evaluation. [less ▲]

Toward a single definition of periurban areas? A review of terms, definitions and characteristics relating to the "urban" terminology.

Poster (2012, February 10)

Remote sensing image interpretation and classification require a clear definition of what is considered as a rural, a periurban, a suburban or an urban area. Such a definition is also essential in order ... [more ▼]

Remote sensing image interpretation and classification require a clear definition of what is considered as a rural, a periurban, a suburban or an urban area. Such a definition is also essential in order to compare results of studies in periurban zones. Different terms, definitions and characteristics relating to these four concepts have been reviewed in the literature and compared according to different criteria like their type, citation frequency, strenghts and weaknesses, in the scope of a landscape evolution analysis. [less ▲]

Volatile organic compounds released by barley roots attract wireworms

Poster (2012, February 10)

Wireworms are the soil dwelling larvae of click beetles and are pests of many crops worldwide. Alternatives to insecticide treatments are needed in order to develop integrated management strategies. Our ... [more ▼]

Wireworms are the soil dwelling larvae of click beetles and are pests of many crops worldwide. Alternatives to insecticide treatments are needed in order to develop integrated management strategies. Our work consists in elucidating the role of barley root-emitted volatile organic compounds on the orientation behaviour of Agriotes sordidus wireworms. Using a dual choice olfactometer we have evaluated the attractiveness of a variety of baits ranging from barley roots themselves to isolated root-emitted volatile organic compounds. Wireworms were significantly attracted towards most of the tested baits. Our results should be taken into account in varietal selection, in crop rotation, or in trapping systems aiming at the reduction of the populations of this pest. [less ▲]

Use of Chrysoperla carnea larvae for biological control of immature stages of Leptinotarsa decemlineata

Poster (2012, February 10)

In laboratory assays, we demonstrated predation of Chrysoperla carnea lacewing larvae against eggs, first and second larval instars of Colorado potato beetle (CPB). When looking at the daily consumption ... [more ▼]

In laboratory assays, we demonstrated predation of Chrysoperla carnea lacewing larvae against eggs, first and second larval instars of Colorado potato beetle (CPB). When looking at the daily consumption, we found that prey consumption by the third larval instar was 3-fold higher compared to the two first instars. Partial or total consumption of prey was also numbered. Different proportions of partial/total consumption were found and these depend on the lacewing larval stage. This study provides new perspectives for possible use of C. carnea as a biological agent to control CPB. Nevertheless, additional work has to be conducted under semi-natural and field to completely evaluate this predatory potential. [less ▲]