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See detailDétermination de la durabilité des complexes parois et toitures vis-à-vis d’attaques biologiques
Jourez, Benoît ULg; Hebert, Jacques ULg; Christiaens, Christophe ULg et al

Conference given outside the academic context (2014)

Le secteur de la construction est en perpétuel évolution et de nouveaux systèmes constructifs sont proposés aux candidats bâtisseurs. Ils vissent à répondre aux nouvelles exigences de performance ... [more ▼]

Le secteur de la construction est en perpétuel évolution et de nouveaux systèmes constructifs sont proposés aux candidats bâtisseurs. Ils vissent à répondre aux nouvelles exigences de performance (mécanique, acoustique, thermique), de développement durable ainsi qu'à des exigences économiques. Néanmoins, ces nouveaux systèmes constructifs innovants, pour lesquels un manque de recul est observé, doivent encore démontrer leur capacité à maintenir dans le temps leur efficacité initiale et leur durabilité afin d'aboutir à des systèmes performants, durables et sans risques de pathologie. A ce titre, ces complexes, la paroi perspirante et la toiture plate compacte, doivent faire l'objet d'investigations en vue d'évaluer leur durabilité vis-à-vis des attaques par les agents de dégradation biologique. La tendance actuelle s'oriente vers des complexes constitués en majorité de matériaux biodégradables (bois, panneau, isolant naturel) tout en évitant l'emploi de produits nocifs pour la santé des habitants qui sont de plus en plus conscients de leur empreinte écologique et réticents à l'incorporation de substances chimiques potentiellement nocives. Il est à noter cependant que les constituants de ces complexes bien que biodégradables doivent aussi faire preuve d'une durabilité suffisante qui ne devrait pas être limitée à la durée de la garantie décennale assumée par le concepteur/entrepreneur du bâtiment mais s'étendre à la durée de vie de celui-ci. L'origine du projet OPTIDUBO repose sur le fait que le comportement hygroscopique de ces complexes et leur durabilité face à l'attaque des agents biologiques de dégradation (insectes xylophages et champignons lignivores) sont peu connus ou documentés alors que ceux-ci sont de plus en plus utilisés dans la construction d'habitations. Ce chapitre se focalise sur la détermination de la durabilité des complexes parois perspirantes et toiture plate compacte vis-à-vis des agents biologiques de dégradation. Il vise à répondre aux deux questions suivantes:  Dans ces complexes, un ou plusieurs des constituants de la paroi sont-ils attaquables ?  Le traitement de l'isolant au sel de bore est-il susceptible de protéger efficacement le complexe de toute attaque? [less ▲]

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See detailTheoretical studies of PbTiO3 and SrTiO3 under uniaxial mechanical constraints combining first-principles calculations and phenomenological Landau theory
Sharma, Henu ULg

Doctoral thesis (2014)

In the present thesis we present theoretical studies of perovskite compounds under uniaxial mechanical constraints combining first-principles DFT calculations approach and phenomenological Landau theory ... [more ▼]

In the present thesis we present theoretical studies of perovskite compounds under uniaxial mechanical constraints combining first-principles DFT calculations approach and phenomenological Landau theory. ABO$_3$ perovskites form a very important class of functional materials that can exhibit a broad range of properties (e.g., superconductivity, magnetism, ferroelectricity, multiferroism, metal-insulator transitions\ldots) within small distortions of the same simple prototype cubic structure. Though these compounds have been extensively studied both experimentally and computationally, there are still unresolved issues regarding the effect of pressure. In recent years, strain engineering has reported to be an original approach to tune the ferroelectric properties of perovskite ABO$_3$ compounds. While the effect of epitaxial biaxial strain and hydrostatic strain is rather well understood in this class of materials, very little is yet known regarding the effect of uniaxial mechanical constraints. Our study is motivated by the little existing understanding of the effect of uniaxial strain and stress, that has been up to now almost totally neglected. Two prototype compounds are studied in detail: PbTiO$_3$ and SrTiO$_3$. After a general introduction on ABO$_3$ compounds and calculations techniques (ab initio and phenomenological Landau model), we studied the effect of mechanical constraints in these compounds in our thesis. PbTiO$_3$ is a prototypical ferroelectric compound and also one of the parent components of the Pb(Zr,Ti)O$_3$ solid solution (PZT), which is the most widely used piezoelectrics. For PbTiO$_3$, we have shown that irrespectively of the uniaxial mechanical constraint applied, the system keeps a purely ferroelectric ground-state, with the polarization aligned either along the constraint direction ($FE_z$ phase) or along one of the pseudo-cubic axis perpendicular to it ($FE_x$ phase). This contrasts with the case of isotropic or biaxial mechanical constraints for which novel phases combining ferroelectric and antiferrodistortive motions have been previously reported. Under uniaxial strain, PbTiO$_3$ switches from a $FE_x$ ground state under compressive strain to $FE_z$ ground-state under tensile strain, beyond a critical strain $\eta_{zz}^c \approx +1$\%. Under uniaxial stress, PbTiO$_3$ exhibits either a $FE_x$ ground state under compression ($\sigma_{zz} < 0$) or a $FE_z$ ground state under tension ($\sigma_{zz} > 0$). Here, however, an abrupt jump of the structural parameters is also predicted under both compressive and tensile stresses at critical values $\sigma_{zz} \approx$ $+2$ GPa and $- 8$ GPa. This behavior appears similar to that predicted under negative isotropic pressure and might reveal practically useful to enhance the piezoelectric response in nanodevices. The second compound of interest is SrTiO$_3$. It has been widely studied in the past decades due to its unusual properties at low temperature. In this work, we have extended our previous investigations on PbTiO$_3$ by exploring theoretically the pressure effects on perovskite SrTiO$_3$ combining the first-principles calculations and a phenomenological Landau model. We have discussed the evolution of phonon frequencies of SrTiO$_3$ with the three isotropic, uniaxial and biaxial strains using first-principles calculations. We also reproduce the previous work done in SrTiO$_3$ with epitaxial strain and hydrostatic strain. Finally, we have calculated the phase diagram of SrTiO$_3$ under uniaxial strain, as obtained from Landau theory and discussed how it compares with the first-principles calculations. [less ▲]

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See detailA case of trichurosis in gilts and fattening pigs
Caron, Yannick ULg; Delleur, Valery ULg; Cassart, Dominique ULg et al

in JMM Case Reports (2014)

Trichuris suis, also called whipworm, is a parasite of the caecum and colon distributed widely and considered as a fairly common parasite in swine. It may be responsible for porcine trichurosis ... [more ▼]

Trichuris suis, also called whipworm, is a parasite of the caecum and colon distributed widely and considered as a fairly common parasite in swine. It may be responsible for porcine trichurosis characterized by diarrhoea, anorexia, growth retardation, dehydration, emaciation and anaemia. This report presents a case of trichurosis diagnosed in a farrow-to-finish Belgian pig herd. The infection was associated with severe and persistent diarrhoea, growth retardation, emaciation and/or anaemia in 10 recently purchased gilts and in fattening pigs. In gilts, levamisole [8 mg/kg body weight] administered once per os gave a good clinical response, as diarrhoea resolved in nine gilts out of 10. In parallel, for these nine gilts, the number of eggs of T. suis/g faeces passed decreased from 12 400 to less than 100 eggs. In fattening pigs, flubendazole (1 mg/kg BW) administrated over 5 days in drinking water allowed a reduction in the number of T. suis eggs/g and was effective against diarrhoea. Although most of the time pig whipworm infections are light and asymptomatic, in some cases when large numbers of worms are present, they can cause watery to bloody diarrhoea that can lead to anaemia. This less frequent disease should not be forgotten in the differential diagnosis of persistent diarrhoea in growing pigs. [less ▲]

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See detailFITNESS EVALUATION OF A RECOMBINANT MURINE NOROVIRUS DURING SERIAL PASSAGES IN CELL CULTURE
Oliveira-Filho, Edmilson; Di Felice, Elisabetta; Toffoli, Barbara et al

Poster (2014, September 28)

Noroviruses are single stranded positive sense RNA viruses which can infect human and different animal species. Human norovirus (NoV) infections are among the most important causes of gastroenteritis in ... [more ▼]

Noroviruses are single stranded positive sense RNA viruses which can infect human and different animal species. Human norovirus (NoV) infections are among the most important causes of gastroenteritis in both children and adults. Infections often occur as outbreaks which may be foodborne. Due to the lack of an efficient cell culture system as well as a workable animal model, many aspects of the NoV infection in human are still poorly understood. The murine norovirus (MuNoV) grows easily in cell culture in contrast to the Human NoV, and constitutes an excellent animal model. Recombination can dramatically change virulence properties of the viruses and has been evidenced in silico for different human NoV strains isolated from clinical cases. Recently, after in vitro coinfection of RAW264.7 cells with parental MuNoV strains CW1 and Wu20, we obtained a recombinant Wu20/CW1 strain. This recombinant strain showed reduced plaque size compared to the parental strains. The aim of the study was to observe and molecularly characterize the natural genetic evolution of the recombinant MuNoV strain across in vitro replications. Viral fitness is a complex concept. Here we defined this fitness as the ability of a viral population to adapt to the cell culture system. Thus, the recombinant strain was serially replicated in vitro in RAW264.7 cells (up to 14 passages). Viral plaque sizes of early and late progenies were compared with the Image J software. A significant difference was shown between them with the Mann and Whitney non parametric statistical test. Afterwards, viruses from different cell passages were cloned and sequenced. The average plaque size increased from the earlier to the later progenies (from 0.1 mm2 to around 0.5 mm2). Molecular investigations are currently performed in order to specify in which genetic region mutations occur and whether or not this could explain fitness modifications during in vitro evolution. In addition, two other parameters of in vitro virulence modification will be investigated: (i) virus production and (ii) one step growth kinetics. The data should provide interesting information about genetic evolution in the genus Norovirus, especially regarding recombination events and explain how a recombinant strain, first disadvantaged compared to its parental strains, could regain fitness by genetic evolution. [less ▲]

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See detailIncreased of exhaled breath condensate neutrophil chemotaxis in acute exacerbation of COPD.
Corhay, Jean-Louis ULg; MOERMANS, Catherine ULg; HENKET, Monique ULg et al

in Respiratory research (2014), 15

BACKGROUND: Neutrophils have been involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Underlying mechanisms of neutrophil accumulation in the airways of stable and exacerbated ... [more ▼]

BACKGROUND: Neutrophils have been involved in the pathogenesis of chronic obstructive pulmonary disease (COPD). Underlying mechanisms of neutrophil accumulation in the airways of stable and exacerbated COPD patients are poorly understood. The aim of this study was to assess exhaled breath condensate (EBC) neutrophil chemotactic activity, the level of two chemoattractants for neutrophils (GRO-alpha and LTB4) during the course of an acute exacerbation of COPD (AECOPD). METHODS: 50 ex smoking COPD patients (33 with acute exacerbation and 17 in stable disease) and 20 matched ex smoking healthy controls were compared. EBC was collected by using a commercially available condenser (EcoScreen(R)). EBC neutrophil chemotactic activity (NCA) was assessed by using Boyden microchambers. Chemotactic index (CI) was used to evaluate cell migration. LTB4 and GROalpha levels were measured by a specific enzyme immunoassay in EBC. RESULTS: Stable COPD and outpatients with AECOPD, but not hospitalized with AECOPD, had raised EBC NCA compared to healthy subjects (p < 0.05 and p < 0.01 respectively). In outpatients with AECOPD EBC NCA significantly decreased 6 weeks after the exacerbation. Overall EBC NCA was weakly correlated with sputum neutrophil counts (r = 0.26, p < 0.05). CONCLUSIONS: EBC NCA rose during acute exacerbation of COPD in ambulatory patients and decreased at recovery. While LTB4 seems to play a role both in stable and in exacerbated phase of the disease, the role of GRO-alpha as a chemotactic factor during AECOPD is not clearly established and needs further investigation. [less ▲]

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See detailLe rôle des historiens dans le processus de reconversion des sites industriels en Wallonie
Destatte, Julien ULg; Defechereux, Olivier ULg; Peters, Arnaud ULg

Conference given outside the academic context (2014)

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See detailDie Rezeption Thibauts in Belgien und Frankreich
Gerkens, Jean-François ULg

Conference (2014, September 27)

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See detailDysphasie : Réflexions autour de la définition et des critères diagnostiques
Leclercq, Anne-Lise ULg; Maillart, Christelle ULg

in Les entretiens de Bichat : les entretiens d'orthophonie 2014 : Les "dys", état de l'art et orientations cliniques (2014, September 27)

Specific language impairment refers to a non-homogeneous group: linguistic and non-linguistic abilities differ from one child to another. Increasing knowledge in this field has led to clarify both the ... [more ▼]

Specific language impairment refers to a non-homogeneous group: linguistic and non-linguistic abilities differ from one child to another. Increasing knowledge in this field has led to clarify both the definition and the diagnostic criteria in order to facilitate its diagnosis. However, the clinical complexity of this trouble questions the relevance of these diagnostic criteria. The present article intends to think about the clinical diagnostic of specific language impairment in order to allow informed decision making during its assessment and therapy. [less ▲]

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See detailDosage de la vitamine D: Point de vue du Biologiste
CAVALIER, Etienne ULg

Conference (2014, September 27)

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See detailFORMATION: Atelier clinique en prise en charge neuropsychologique
Adam, Stéphane ULg

Diverse speeche and writing (2014)

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See detailL'harmonisation des statuts entre ouvriers et employés
Baukens, Michèle; Rozenberg, Fanny ULg; Kéfer, Fabienne ULg

Book published by Anthemis (2014)

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See detailAgricultures de demain? Produire avec la nature...
Hatt, Séverin ULg; Brédart, David ULg

Conference given outside the academic context (2014)

Baisse de la biodiversité, pollution de l’eau, crises alimentaires, diminution du nombre d’agriculteurs… ces sujets régulièrement présents dans l’actualité remettent en question le modèle industriel de la ... [more ▼]

Baisse de la biodiversité, pollution de l’eau, crises alimentaires, diminution du nombre d’agriculteurs… ces sujets régulièrement présents dans l’actualité remettent en question le modèle industriel de la production agricole. Nous présenterons des alternatives actuellement développées par des agriculteurs et des chercheurs. Nous proposons, par exemple, de découvrir des dispositifs qui réduisent l’utilisation de pesticides ou de fertilisants. [less ▲]

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See detailEFFICACY and Characterization of THE LACTOPEROXIDASE SYSTEM, A NATURAL BIOLOGICAL PESTICIDE
Bafort, Françoise ULg; Perraudin, Jean-Paul; Jijakli, Haissam ULg

Conference (2014, September 26)

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See detailOne click… and a novel Antibiotic !
Rigali, Sébastien ULg

Scientific conference (2014, September 26)

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See detailLe secret des crèmes foisonnées
Petrut, Raul Flaviu ULg; Danthine, Sabine ULg; Blecker, Christophe ULg

Poster (2014, September 26)

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See detailDetection of non-concave and non-increasing spectra: Snu spaces revisited with wavelet leaders
Esser, Céline ULg

Conference (2014, September 26)

Our objective is to study the pointwise regularity of functions via their multifractal spectrum. Computing the multifractal spectrum of a function using directly its definition is an unattainable goal in ... [more ▼]

Our objective is to study the pointwise regularity of functions via their multifractal spectrum. Computing the multifractal spectrum of a function using directly its definition is an unattainable goal in most of the practical cases, but there exist heuristic methods, called multifractal formalisms, which allow to estimate this spectrum and which give satisfactory results in many situations. The Frisch-Parisi conjecture, classically used and based on Besov spaces, presents two disadvantages: it can only hold for spectra that are concave and it can only yield the increasing part of spectra. Concerning the first problem, the use of S spaces allows to deal with non-concave increasing spectra. Concerning the second problem, a generalization of the Frisch-Parisi conjecture obtained by replacing the role played by wavelet coefficients by wavelet leaders allows to recover the decreasing part of concave spectra. We present a combination of both approaches to define a new formalism derived from large deviations based on statistics of wavelet leaders. We also present the associated function space. [less ▲]

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See detailGenericity and classes of ultradifferentiable functions
Esser, Céline ULg

Conference (2014, September 26)

As surprising as it may seem, there exist infinitely differentiable functions which are nowhere analytic. When such an unexpected object is found, a natural question is to ask whether many similar ones ... [more ▼]

As surprising as it may seem, there exist infinitely differentiable functions which are nowhere analytic. When such an unexpected object is found, a natural question is to ask whether many similar ones may exist. A classical technique is to use the Baire category theorem and the notion of residuality. This notion is purely topological and does not give any information about the measure of the set of objects satisfying such a property. In this purpose, the notion of prevalence has been introduced. Moreover, one could also wonder whether large algebraic structures of such objects can be constructed. This question is formalized by the notion of lineability. The first objective of this talk is to go further into the study of nowhere analytic functions. It is known that the set of nowhere analytic functions is residual and lineable in C^infty([0, 1]). We prove that the set of nowhere analytic functions is also prevalent in this space. Those results of genericity are then generalized using Gevrey classes, which can be seen as intermediate between the space of analytic functions and the space of infinitely differentiable functions. We also study how far such results of genericity could be extended to spaces of ultradifferentiable functions, defined using weight sequences. [less ▲]

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