Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailInfluence of the protein context on the propensity of polyglutamine tracts to trigger amyloid fibril formation
Huynen, Céline ULg

Conference (2012, November 16)

10 neurodegenerative diseases are associated with 10 proteins containing an expanded polyglutamine (polyQ) tract higher than a threshold of 35-45Q. This polyQ tracts trigger the aggregation of the ... [more ▼]

10 neurodegenerative diseases are associated with 10 proteins containing an expanded polyglutamine (polyQ) tract higher than a threshold of 35-45Q. This polyQ tracts trigger the aggregation of the proteins into amyloid fibrils that could play an important role in the disease. It is therefore necessary to investigate the aggregation properties of polyQ proteins. Accordingly, we have created model proteins made of the β-lactamase BlaP with 23 to 79Q inserted at positions 197 or 216. Their aggregation behaviour recapitulate those of disease-associated proteins (i.e. a threshold and the anticipation phenomenon). Moreover, the threshold depends on the structural integrity of BlaP (which applies constraints to the polyQ). In this work, we investigate the role of the protein context in the aggregation process using two techniques: QCM-D coupled with AFM. We observe that the native conformation of BlaP is the barrier for fibril formation, interfering with the nucleation step. Moreover, the protein environment of the polyQ (position 197 or 216) influences its propensity to form fibrils. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
See detailInfluence of the protéin context on the propensity of polyglutamine tracts to trigger protein aggregation into amyloid fibrils
Huynen, Céline ULg

Conference (2012, September 13)

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 pathological 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 large and relatively insoluble, they are difficult to produce and handle experimentally. We have therefore decided to study the aggregation 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 either at positions 197 or 216 of BlaP. The aggregation behaviour of BlaP chimeras recapitulate those of proteins associated with polyQ diseases. We indeed observed that there is a minimal number of glutamines (i.e. a threshold) required for the 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 of oligomers on the aggregation process 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). QCM-D studies indicate that, under native condition, there is a minimal number of glutamines required for the elongation of BlaP197(Gln)79 fibrils by BlaP chimeras containing a polyQ tract in position 197. This threshold is lower than that observed for the aggregation assays monitored in solution in the absence of seed; it corresponds however to the threshold for fibril formation observed under denaturing conditions. These observations suggest that the conformation of BlaP is the limiting step for amyloid fibril formation by interfering with the nucleation step. BlaP chimeras containing 55Q or more in position 216 of BlaP also elongate BlaP197(Gln)79 fibrils. Interestingly this rate of cross-elongation is faster than the elongation rate observed with BlaP197(Gln)55 and BlaP197(Gln)79. This observation demonstrates that the protein environment of the polyQ tract influences its propensity to form amyloid fibrils. Finally, preliminary DLS experiments indicate that oligomers formed by BlaP197(Gln)79 under native condition are on-pathway of amyloid fibril formation and could act as aggregation nuclei. [less ▲]

Detailed reference viewed: 84 (11 ULg)
Peer Reviewed
See detailInfluence of the prying effects on the fatigue resistance of the bolts
Piraprez, E.; Jaspart, Jean-Pierre ULg

in Proceedings of the VTT Symposium 155 on fatigue Design 1995, volume 2 (1995)

Detailed reference viewed: 19 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the range of motion on the isokinetic performances of the knee flexors and extensors
Croisier, Jean-Louis ULg; Voisin, P.; Elbouz, Leila ULg et al

in Isokinetics & Exercise Science (2003, March), 11

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailInfluence of the rare-earth element on the effects of the structural and magnetic phase transitions in CeFeAsO, PrFeAsO and NdFeAsO
McGuire, Michael A; Hermann, Raphaël ULg; Sefat, Athena S et al

in New Journal of Physics (2009), 11

We present results of transport and magnetic properties and heat capacity measurements on polycrystalline CeFeAsO, PrFeAsO and NdFeAsO. These materials undergo structural phase transitions, spin density ... [more ▼]

We present results of transport and magnetic properties and heat capacity measurements on polycrystalline CeFeAsO, PrFeAsO and NdFeAsO. These materials undergo structural phase transitions, spin density wave-like magnetic ordering of small moments on iron and antiferromagnetic ordering of rare-earth moments. The temperature dependence of the electrical resistivity, Seebeck coefficient, thermal conductivity, Hall coefficient and magnetoresistance are reported. The magnetic behavior of the materials have been investigated using Mossbauer spectroscopy and magnetization measurements. Transport and magnetic properties are affected strongly by the structural and magnetic transitions, suggesting significant changes in the band structure and/or carrier mobilities occur, and phonon-phonon scattering is reduced upon transformation to the low-temperature structure. Results are compared with recent reports for LaFeAsO, and systematic variations in properties as the identity of Ln is changed are observed and discussed. As Ln progresses across the rare-earth series from La to Nd, an increase in the hole contributions to the Seebeck coefficient and increases in magnetoresistance and the Hall coefficient are observed in the low-temperature phase. Analysis of hyperfine fields at the iron nuclei determined from Mossbauer spectra indicates that the moment on Fe in the orthorhombic phase is nearly independent of the identity of Ln, in apparent contrast to reports of powder neutron diffraction refinements. [less ▲]

Detailed reference viewed: 18 (3 ULg)
Peer Reviewed
See detailInfluence of the reactional system on the irrigation rate in trickle-bed reactors
Ruiz, Pato; Crine, Michel ULg; Germain, Albert ULg et al

in Chemical and Catalytic Reactor Modelling (1984)

Detailed reference viewed: 25 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the relative alveoli widths on Piano Key Weirs efficiency for varied weir heights
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proceedings of Int. Symp. on Dams for a changing world (2012)

In the scope of dam rehabilitation to manage floods increase or to increase water storage, the Piano Key Weir is a good solution for concrete dams. Indeed, its labyrinth shape allows discharge capacities ... [more ▼]

In the scope of dam rehabilitation to manage floods increase or to increase water storage, the Piano Key Weir is a good solution for concrete dams. Indeed, its labyrinth shape allows discharge capacities until 4 times more important than traditional ogee-crested weirs and 10 percent more important than labyrinth weirs of same horizontal geometry. Furthermore, the use of up- and downstream overhangs reduces drastically its footprint and enables its use directly on dams crest. The efficiency of Piano Key Weirs is now well demonstrated through various experimental studies. Even if parametrical studies are currently undertaken, the definition of the optimal shape to give to the structure is still missing due to the lack of knowledge in the influence of the large set of geometrical parameters. This paper presents the results of a combine experimental and numerical study about the influence of the relative alveoli widths on the Piano Key Weir discharge capacity. 14 models have been tested providing results for a large range of the inlet to outlet widths ratio and considering variation of the weir height in accordance with former studies. The results of the experiments enable to define optimal values for a common variation of these two parameters. [less ▲]

Detailed reference viewed: 42 (5 ULg)
Full Text
See detailInfluence of the resonator damping on its coupling with a slot-tone
Glesser, Martin; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2005, July)

In ventilation systems, disturbing whistlings can occur at outlets. This whistling phenomenon belongs to the self-sustained tones class which can be produced when a low velocity flow impinges on a ... [more ▼]

In ventilation systems, disturbing whistlings can occur at outlets. This whistling phenomenon belongs to the self-sustained tones class which can be produced when a low velocity flow impinges on a downstream obstacle. The coupling of the tones with acoustic resonances (so-called indirect feedback path) can promote high-level harmonic noises. This experimental study deals with the coupling of a jet-slot oscillator, modelling a ventilation outlet, with the flow supply duct resonances. The flow supply duct is damped by using various amounts of acoustic damping foam, and the effect of this damping on the sound production is studied. It is shown that for a jet exit/obstacle distance higher than 2.5 jet height (L/H>2.5), the tone’s frequency matches satisfactorily with frequencies predicted by a model describing favourable phase relationships for the occurrence of tones along the feedback loop. When the flow supply duct is resonant, it is noticeable that the tone’s frequency occurs at a duct resonance frequency which is close to the frequency described by this model. For lower values of L/H (slot closer to the jet exit), a better knowledge of the convection velocity behaviour along the vortices path could improve the tone’s frequency prediction. The use of damping foam within the flow supply duct prevents the occurrence of the tones’ coupling with a duct resonance, especially with high amounts of damping material, and dramatically reduces the emitted acoustic levels. For moderate amounts of damping material, the suppression of coupling occurs only for higher flow speeds, as the tone’s frequencies are higher and the damping material is then more efficient. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the reuse of OSB and marine plywood formworks on concrete surface aesthetics
Courard, Luc ULg; Martin, Marie; Goffinet, Cécile et al

in Materials and Structures (2012), 45(9), 1331-1343

Concrete surface quality becomes more and more important because aesthetics requirements tend to spread over a wide variety of construction works. Even if it is difficult to clearly define what is ... [more ▼]

Concrete surface quality becomes more and more important because aesthetics requirements tend to spread over a wide variety of construction works. Even if it is difficult to clearly define what is beautiful or not, existing techniques maybe used to quantify aesthetic properties of concrete. As they mainly depend on formwork, the research project focuses on the reuse of two types of panels – plywood and OSB – and two types of release agents – vegetal and mineral oils. Evolution of surface properties is measured through lightness and absorption. For plywood formworks, beyond 80 reuses, a modification of surface quality is noticed; this is only 50 for OSB panels. For both types of formworks, the release oil doesn’t seem to have a major influence on formwork absorption. It is also observed that alkalis cause early degradation of the panels: release agents are not always efficient to avoid this phenomenon. Finally, if reuse doesn’t have any influence on the absorption of the plywood formworks, it is not the case for OSB formworks. [less ▲]

Detailed reference viewed: 40 (3 ULg)
Peer Reviewed
See detailInfluence of the section and of the insulation type of the equivalent time
Cadorin, Jean-François; Pérez Jiménez, C.; Franssen, Jean-Marc ULg

in Bradley, D. (Ed.) Proceedings of the 4th International Seminar Fire and Explosion Hazards (2004)

Detailed reference viewed: 19 (3 ULg)
Peer Reviewed
See detailInfluence of the section and of the insulation type on the equivalent time
Cadorin, Jean-François; Perez, Christian; Franssen, Jean-Marc ULg

in Proceedings of the 4th International Seminar on Fire and Explosion Hazards (2003, September)

Detailed reference viewed: 15 (3 ULg)
Full Text
Peer Reviewed
See detailInfluence of the shaping effect on hardness homogeneity by Vickers indentation analysis
Guillaume, Bernard ULg; Boschini, Frédéric ULg; Rulmont, André ULg et al

in Journal of the European Ceramic Society (2006), 26(15), 3191-3196

In this study, indentation technique (Vickers indentation) has been unconventionally used to evaluate the homogeneity of barium zirconate ceramic samples which have been shaped through different routes ... [more ▼]

In this study, indentation technique (Vickers indentation) has been unconventionally used to evaluate the homogeneity of barium zirconate ceramic samples which have been shaped through different routes. Statistical tools have been used to estimate the con-elation which can be established between heterogeneities within the samples and their shaping ways. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 42 (1 ULg)
Full Text
Peer Reviewed
See detailInfluence of the shielding currents lengthscale and anisotropy effects on the magnetic flux profiles of high-temperature superconductors
Vanderbemden, Philippe ULg; Lovchinov, Vassil

in Journal of Physics: Conference Series (2012), 398

The so-called "magnetic flux profile" AC inductive technique is a powerful method for determining the critical current density Jc of bulk superconductors. In this work we aim at reporting analytical ... [more ▼]

The so-called "magnetic flux profile" AC inductive technique is a powerful method for determining the critical current density Jc of bulk superconductors. In this work we aim at reporting analytical expressions for magnetic flux profiles of superconducting rectangular samples exhibiting a critical current density anisotropy. The results are used for examining the error resulting from approximating a rectangular cross-section by an "infinite cylinder" or "infinite slab" geometry. It is found that such approximations can lead to an artificial curvature of the flux profiles and errors of 10%–20% in the determination of Jc. Next, the effects of how planar defects (cracks, platelet boundaries,...) affect the magnetic flux profile signal are discussed. It is found that the magnetic flux profiles are much sensitive to the lengthscale of shielding currents, thereby providing means of investigation of the typical size of induced current loops in bulk superconductors. Finally some illustrative flux profile data measured on a bulk, large grain melt-processed YBCO single domain exhibiting Jc anisotropy are presented and discussed in relation with theoretical predictions. [less ▲]

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
See detailInfluence of the surface morphology of smooth platinum electrodes for the sodium borohydride oxidation reaction
Olu, Pierre-Yves; Gilles, Bruno; Job, Nathalie ULg et al

in Electrochemistry Communications (2014), 43

Detailed reference viewed: 56 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence of the temperature on the tensile behaviour of a modified 9Cr–1Mo T91 martensitic steel
Keller, Clément ULg; Margulies, Monique; Hadjem-Hamouche, Zehoua et al

in Material Science and Engineering A (2010), 527

The tensile behaviour of a modified 9Cr–1Mo T91 martensitic steel is investigated for temperatures between 300 and 700 K. Loading/unloading tensile tests are carried out to investigate the evolution of ... [more ▼]

The tensile behaviour of a modified 9Cr–1Mo T91 martensitic steel is investigated for temperatures between 300 and 700 K. Loading/unloading tensile tests are carried out to investigate the evolution of the tensile flow parameters and the different flow stress components with temperature. An increase in temperature reduces the ductility and the ultimate tensile stress. Three different deformation mechanisms are operative depending on the temperature. These mechanisms are discussed in terms of activation volume, dislocation motion and dynamic strain ageing. [less ▲]

Detailed reference viewed: 30 (5 ULg)
See detailThe influence of the token frequency on the generalization of construction schemas in French-speaking children with SLI
Leroy, Sandrine ULg; Parisse, Christophe; Moulin, Mélissa et al

Poster (2012, June)

Constructivist approach (Goldberg, 1995 ; Tomasello, 2003) postulates that children build their linguistic system from their own linguistic experience. To be productive with their language, children have ... [more ▼]

Constructivist approach (Goldberg, 1995 ; Tomasello, 2003) postulates that children build their linguistic system from their own linguistic experience. To be productive with their language, children have to generalize construction schemas to never heard items. Because children with SLI seem to show limited morphosyntactic creativity and variability, we hypothesize that they would have difficulties to generalize their construction schemas what would hinder their access to the most abstract level of their linguistic competence. Given this lack of productivity of construction schemas in children with SLI, they would produce more lexicalized forms than abstract form what would lead to a limitation of the linguistic competence. The aim of our study was to test if children with SLI had more difficulties than children with typical language development (TLD) to generalize a schema to new items. Given the role of the token frequency in the abstraction of construction schemas (cf. Bybee, 1995), we decided to create a task in which we manipulated this variable. [less ▲]

Detailed reference viewed: 45 (8 ULg)
Full Text
Peer Reviewed
See detailInfluence of the Transfer Climate and Job Attitudes on the Transfer Process: Modelling the Direct and Indirect Effects
Peters, Stéphanie ULg; Cossette, Michel; Bates, Reid et al

in Journal of Personnel Psychology (in press)

This study investigates the impact job satisfaction, job involvement, organizational commitment and transfer climate on the training transfer process. Training transfer refers to the application of the ... [more ▼]

This study investigates the impact job satisfaction, job involvement, organizational commitment and transfer climate on the training transfer process. Training transfer refers to the application of the new learning and to performance at work. A two-time data collection was implemented among employees of a public health insurance company who attended professional training programs (N=118). Data analysis revealed that (1) job involvement negatively influenced transfer; (2) peer support positively influenced transfer; (3) openness to change had a negative relationship with transfer; and (4) these three predictors have an indirect effect on performance at work. [less ▲]

Detailed reference viewed: 20 (0 ULg)