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
Peer Reviewed
See detailInfluence of the metal electronic properties on the sum-frequency generation spectra of dodecanethiol self-assembled monolayers on Pt (111), Ag (111) and Au (111) single crystals
Dreesen, Laurent ULg; Humbert, Christophe; Celebi, M. et al

in Applied Physics B : Lasers & Optics (2002), 74

Infrared-visible sum-frequency generation (SFG) spectroscopy is performed at different visible wavelengths between 450 and 650 nm in order to investigate the interaction between metallic substrates (Pt ... [more ▼]

Infrared-visible sum-frequency generation (SFG) spectroscopy is performed at different visible wavelengths between 450 and 650 nm in order to investigate the interaction between metallic substrates (Pt, Ag and Au) and 1-dodecanethiol self-assembled monolayers. We show that such measurements provide a means to study the electronic properties of metals as well as the interference phenomena between the SFG signals from the adsorbate and the substrate. The common features of the three interfaces are the vibration modes of the terminal methyl groups. However, these resonances appear as peaks for Pt (111) and as dips in the case of Ag (111). Their shape is not modified when the visible wavelength is tuned between 450 and 650 nm. Moreover, the metal sum-frequency generation contribution is slightly modified in that spectral range. For Au (111) samples, the sum-frequency generation spectrum drastically evolves with the visible wavelength: the peak resonant sum-frequency generation signal at 450 nm becomes rather dip-shaped at 650 nm. The non-linear response of gold is also enhanced when the wavelength associated with the sum-frequency process is close to 480 nm. These results are interpreted on the basis of the metal electronic properties that are responsible for the non-resonant contribution to the SFG signal. [less ▲]

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence Of The Mode Of Insertion Of Siv Peptides Into Membranes On The Structure Of Model Membrane As Studied By P-31 Nmr
Schanck, A.; Peuvot, J.; Brasseur, Robert ULg

in Biochemical and Biophysical Research Communications (1998), 250(1), 12-4

The influence on model membrane organization of a fusion peptide of SIV and of a nonfusogenic mutant of this peptide was examined by molecular modeling and by 31P NMR. The calculated mode of insertion of ... [more ▼]

The influence on model membrane organization of a fusion peptide of SIV and of a nonfusogenic mutant of this peptide was examined by molecular modeling and by 31P NMR. The calculated mode of insertion of the fusion peptide shows that it adopts an oblique orientation towards the lipid-water interface and that this fusion peptide induces a destabilization of the bilayer structure of multilamellar vesicles as evidenced by 31P NMR observations. The SIV mutant showing a more vertical insertion into lipid layers is unable to induce nonlamellar structures. This study reinforces the correlation between fusogenic activity, induction of structures not organized in extended bilayers, and calculated mode of insertion of peptides into lipid layers. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the mode of walk on walking speed in multiple sclerosis: are you walking comfortably?
PHAN BA, Remy ULg; DELRUE, Gaël ULg; Pierard, Sébastien ULg et al

Poster (2013, June 10)

Introduction : Walking speed (WS) is the most frequent gait variable taken into account when measuring gait dysfunction in neurological diseases. Influences of the mode of walk instructed to the subject ... [more ▼]

Introduction : Walking speed (WS) is the most frequent gait variable taken into account when measuring gait dysfunction in neurological diseases. Influences of the mode of walk instructed to the subject, i.e. « as fast as possible » (AFAP) or « at a comfortable pace » (PrP) have not been well characterized in multiple sclerosis (MS). Objectives : to compare those 2 mode of walk in a population of persons with MS (pMS) and healthy volunteers (HV). Methods: WS was measured with a new automated device along a 25 foot distance (T25FW) as part of a multimodal evaluation of gait in an MS ambulatory department. Results: Baseline demographics between HV and pMS were comparable. Our first results demonstrate that (i) WS is obviously significantly higher in AFAP than in PrP both for pMS and HV (p < 0.001 for all comparisons) and (ii) the relative difference between AFAP and PrP WS is significantly higher in HV than in pMS (p < 0.001). The AFAP-PrP WS correlation is higher in pMS (r = 0.87, p < 0.001) than in HV (r = 0.51, p < 0.001). Finally, the relative difference between AFAP and PrP WS is significantly and negatively correlated with the PrP WS in HV (r = -0.41, p < 0.001) and pMS with mild to moderate disability (EDSS 0-3.5, r = -0.49, p < 0.01) but not in pMS with high disability (EDSS 4-5.5, r = 0.008). Conclusions : these results suggests that heatlhy subjects have access to a higher range of PrP WS than pMS and questions the regulation of PrP WS that might be under psychological or behavioural influences. The demonstration of a lower PrP-AFAP difference in MS suggests that pMS are either adopting a natural WS closer to their maximum WS, or alternatively that they can’t reach their maximum WS because of neurological impairments. Our results also emphasize the importance of the instructed mode of walk in the quantification of gait disorders both for routine clinical practice and clinical trials. [less ▲]

Detailed reference viewed: 109 (30 ULg)
Full Text
Peer Reviewed
See detailInfluence of the mucosal epithelium microenvironment on Langerhans cells: implications for the development of squamous intraepithelial lesions of the cervix
Giannini, Sandra ULg; Hubert, Pascale ULg; Doyen, Jean ULg et al

in International Journal of Cancer = Journal International du Cancer (2002), 97(5), 654-659

Detailed reference viewed: 18 (3 ULg)
Full Text
Peer Reviewed
See detailInfluence of the Nature of Calcium Salts on Serum Calcium, Phosphorus, Calcitonin, Growth Hormone, and Somatomedin C
Reginster, Jean-Yves ULg; Denis, D.; Albert, Adelin ULg et al

in Research in Experimental Medicine (1988), 188

Twenty healthy males were randomly divided into three groups. Each subject received either 405 mg elemental calcium (Ca) as a salt linked to an amino acid precursor, 405 mg CaC12 or 1000 mg Ca as Ca ... [more ▼]

Twenty healthy males were randomly divided into three groups. Each subject received either 405 mg elemental calcium (Ca) as a salt linked to an amino acid precursor, 405 mg CaC12 or 1000 mg Ca as Ca gluconolactate and carbonate. In all three cases, Ca intake led to an increase of serum Ca and TCT production and a decrease of PTH liberation. However, when Ca is linked to the amino acid precursor, an elective stimulation of growth hormone (GH) and somatomedin C (SmC) occurs. Due to the nature of its amino acid precursor, this salt seems to stimulate GH and SmC liberation through hypophysis. This could be a major pathway in decoupling of the sequence resorption-formation and therapy of metabolic bone diseases. [less ▲]

Detailed reference viewed: 11 (4 ULg)
Peer Reviewed
See detailINFLUENCE OF THE NATURE OF SUGAR RESIDUES ON THE INTERACTIONS OF SYMETRIC SUGAR- BASED BOLAFORMS WITH MODEL MEMBRANES
Nasir, Mehmet Nail ULg; Crowet, Jean-Marc ULg; Lins, Laurence ULg et al

Poster (2013, November)

Glycolipid surfactants constitute a class of natural compound having interest in biological field such as antifungal, antiviral and plant-elicitor and for pharmaceutical formulation as well as for food ... [more ▼]

Glycolipid surfactants constitute a class of natural compound having interest in biological field such as antifungal, antiviral and plant-elicitor and for pharmaceutical formulation as well as for food and cosmetic field. Their action may be modulated through their interactions with plasma membranes of target cells and more particularly by their interactions with membrane lipid molecules. Among glycolipid surfactants, bolaforms constitute an important class; they are composed of two hydrophilic heads connected by a hydrophobic carbon segment.Their interest lies mainly in the development of the efficient and low cost lipid-based drug delivery systems. In this context, our work was focused on two sugar-based bolaforms. They are composed by two identical hydrophilic head constituted by xylose ( BolaX) or rhamnose ( BolaR), connected by an ether link to a hydrocarbon segment with an insaturation. The interactions of  BolaX and BolaR with model phopsholipid and phospholipid/sterol model membranes (Langmuir monolayers at the air-water interface and multilamellar vesicles) were investigated with biophysical and in silico approaches. Our results indicate that both bolaforms interact with model membranes at the level of hydrocarbon chain and, at the phosphate and the carbonyl group of phospholipids. The presence of sterol in the system has an influence on insertion of bolaforms and change slightly the nature of the interactions. The insertion of BolaR within a phospholipid bilayer was deeper than that of  BolaX and its interactions with phospholipids were energetically more favorable, suggesting an important role of the nature of sugar residue. [less ▲]

Detailed reference viewed: 54 (17 ULg)
Full Text
Peer Reviewed
See detailInfluence of the nature of the electrolyte on the chiral separation of basic compounds in nonaqueous capillary electrophoresis using heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin
Servais, Anne-Catherine ULg; Fillet, Marianne ULg; Chiap, Patrice ULg et al

in Journal of Chromatography. A (2005), 1068(1), 143-150

The influence on the enantiomeric resolution of the nature of the cationic BGE component (sodium, ammonium or potassium) and that of the anionic component (chloride, formate, methanesulfonate or ... [more ▼]

The influence on the enantiomeric resolution of the nature of the cationic BGE component (sodium, ammonium or potassium) and that of the anionic component (chloride, formate, methanesulfonate or camphorsulfonate) as well as the concentration of heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD), the selected chiral selector, was studied in nonaqueous capillary electrophoresis (NACE). For this purpose, two D-optimal designs with 33 and 26 experimental points were applied. Three beta-blockers (atenolol, celiprolol and propranolol) and three local anesthetics (bupivacaine, mepivacaine and prilocaine) were selected as basic model compounds. Both cationic and anionic BGE components were found to have a deep impact on the enantiomeric resolution of the investigated analytes but it is the cationic component that has shown the strongest influence. Indeed, in some cases, the change of the latter led to a complete loss of enantioresolution. Based on the observed results, two NACE systems were recommended, namely ammonium formate and potassium camphorsulfonate in a methanolic solution containing HDMS-beta-CD and acidified with formic acid, in order to separate efficiently the enantiomers of basic drugs. (c) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 19 (0 ULg)
Peer Reviewed
See detailInfluence of the non-linear modellings of beam-to-column joints on the structural response of braced and unbraced steel building frames.
Maquoi, René ULg; Jaspart, Jean-Pierre ULg

in proceedings of the Fourth international Colloquium on structural stability Mediterranean session (1991)

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the non-linearity of the aerodynamic coefficients on the skewness of the buffeting drag force
Denoël, Vincent ULg; Degée, Hervé ULg

in Wind and Structures (2006), 9(6), 457-471

This paper is devoted to the non linear quasi-steady aerodynamic loading. A linear approximation is often used to compute the response of structures to buffeting forces. Some researchers have however ... [more ▼]

This paper is devoted to the non linear quasi-steady aerodynamic loading. A linear approximation is often used to compute the response of structures to buffeting forces. Some researchers have however shown that it is possible to account for the non linearity of this loading. This non linearity can come (i) from the squared velocity or (ii) from the shape of the aerodynamic coefficients (as functions of the wind angle of attack). In this paper, it is shown that this second origin can have significant implications on the design of the structure, particularly when the non linearity of the aerodynamic coefficient is important or when the transverse turbulence is important. [less ▲]

Detailed reference viewed: 71 (8 ULg)
Peer Reviewed
See detailInfluence of the nozzle capacity on the performance of a domestic fuel oil boiler
Ngendakumana, Philippe ULg; Masy, Cédric

in 2nd Edition of European Combustion Meeting (ECM 2005) (2005, April)

In order to investigate the influence of the nozzle capacity on the performance of fuel oil boilers, tests have been performed in transient and steady state regimes on our experimental boiler. The aim of ... [more ▼]

In order to investigate the influence of the nozzle capacity on the performance of fuel oil boilers, tests have been performed in transient and steady state regimes on our experimental boiler. The aim of the tests was to deduce the better couple nozzle - fuel injection pressure to reach the desired output power while producing fewer pollutants as possible. In short, a high fuel injection pressure associated with a low capacity nozzle is recommended. [less ▲]

Detailed reference viewed: 20 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of the operating conditions and humidity on adherence of repair mortars
Courard, Luc ULg; Wiertz, Jean; Darimont, Anne ULg et al

in Van Gemert, Dionys (Ed.) Proceedings of the VIIIth International Congress on Polymers in Concrete (1995)

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailInfluence of the operating conditions on the production rate of multi-walled carbon nanotubes in a CVD reactor
Gommes, Cédric ULg; Blacher, Silvia ULg; Bossuot, C. et al

in Carbon (2004), 42(8-9), 1473-1482

A kinetic study is presented for the synthesis of multi-walled carbon nanotubes in a semi-continuous chemical vapor deposition reactor. The study is based on the use of a mass spectrometer that allows the ... [more ▼]

A kinetic study is presented for the synthesis of multi-walled carbon nanotubes in a semi-continuous chemical vapor deposition reactor. The study is based on the use of a mass spectrometer that allows the reaction rate to be inferred from the exhaust gas composition measurements. The tested reactor operating variables are the length and thickness of the catalytic bed, the total feed flow and the molar fraction of hydrocarbon in the feed. The results of the study are analyzed using well known reactor engineering models, which allows the origin of the observed physical limitations to be ascertained. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 56 (20 ULg)
Full Text
See detailInfluence of the oxygen probe location in the furnace on the measured oxygen rate
Dumont, Fabien ULg

Conference (2012, October)

Detailed reference viewed: 23 (6 ULg)
Full Text
Peer Reviewed
See detailInfluence of the PKW height on its discharge capacity
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Within the framework of Piano Key Weir (PKW) development, the hydraulic optimization of its geometry seems essential. First systematic studies of all the geometrical parameters of the PKW highlight a more ... [more ▼]

Within the framework of Piano Key Weir (PKW) development, the hydraulic optimization of its geometry seems essential. First systematic studies of all the geometrical parameters of the PKW highlight a more important influence of some parameters compared to other ones. A former study led, at the University of Liege, on a large scale model of PKW highlights the main influence of the inlet cross section on the global discharge capacity of the weir. Based on this finding, the geometrical parameters influencing the inlet cross section seem to be the most influential parameters of the weir efficiency. This paper presents results of an experimental study using models of PKW with varying height. The mean non-dimensional parameters characterizing the geometry of the models are maintained constant, only varying the slope of the alveoli. The results of the 7 models studied, with a wide range of slopes (height over length) from 0.25 to 1.5, are presented. Based on these results, an analytical formulation of the unit discharge over a PKW as a function of its height is developed. [less ▲]

Detailed reference viewed: 51 (2 ULg)
Full Text
See detailInfluence of the processing parameters on the physicochemical properties of puff pastry margarines
Lefebure, Emilie ULg; Ronkart, Sébastien; Brostaux, Yves ULg et al

Poster (2011, September 18)

Detailed reference viewed: 37 (13 ULg)
Full Text
Peer Reviewed
See detailInfluence of the production of two lipopeptides, Iturin A and Surfactin S1, on oxygen transfer during Bacillus subtilis fermentation
Hbid, Choukri; Jacques, Philippe; Razafindralambo, Hary ULg et al

in Applied Biochemistry and Biotechnology (1996), 57-8

Bacillus subtilis produces three types of lipopeptides: Iturins, Fengycins, and Surfactins. These amphiphilic molecules influence the volumetric oxygen transfer (K(L)a) like chemical surfactant. K(L)a ... [more ▼]

Bacillus subtilis produces three types of lipopeptides: Iturins, Fengycins, and Surfactins. These amphiphilic molecules influence the volumetric oxygen transfer (K(L)a) like chemical surfactant. K(L)a values were from two- to fivefold lower when both Iturin A and Surfactin S1 were coproduced, and from 0.57- to 0.8-fold lower when only Iturin A was produced. The addition of an oxygen vector (n-Dodecane) during fermentation increased K(L)a values (7.5-fold) and biomass production (twofold), and decreased Iturin A and Surfactin S1 production. However, at high stirring conditions and in the presence of n-Dodecane, Iturin A production was improved. [less ▲]

Detailed reference viewed: 48 (21 ULg)
Full Text
See detailInfluence of the protein context in the aggregation of polyQ proteins into amyloid fibrils
Huynen, Céline ULg

Poster (2013, April 18)

Ten neurodegenerative diseases, referred to as polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of ten different proteins containing a polyQ expansion higher than a ... [more ▼]

Ten neurodegenerative diseases, referred to as polyglutamine (polyQ) diseases, are associated with the aggregation into amyloid fibrils of ten different proteins containing a polyQ expansion higher than a pathological threshold comprised between 35 to 45Q (1, 2). A large body of evidence indicate that the polyQ expansion is the critical determinant for the aggregation of these polyQ proteins. The aggregation process of polyQ proteins is, however, still not well understood. To better understand this mechanism at a molecular level, we have characterized model polyQ proteins made of the β-lactamase BlaP from Bacillus licheniformis 749/C and a polyQ tract of 0 to 79Q inserted either at position 197 or position 216 of BlaP. Those chimeras recapitulate the same aggregation behaviours than that of disease-associated polyQ proteins: there is a glutamine threshold for the aggregation into amyloid fibrils and the anticipation phenomenon. Most importantly, the threshold critically depends on the structural integrity of BlaP (3) which would impose some conformational and/or sterical constraints to the polyQ tract. Moreover the position of the polyQ insertion into BlaP modifies the aggregation propensity of BlaP chimeras. The present work aims to further investigate (i) how the protein context affects the different phases of the aggregation phenomenon (i.e. the nucleation and elongation phases) and (ii) the role of the oligomers formed during the early time of the aggregation process. The techniques used are mainly (1) quartz crystal microbalance (QCM) and atomic force microscopy (AFM) to study the elongation step of amyloid fibril formation and (2) dynamic light scattering (DLS) to study the evolution of the different populations formed during the aggregation time course. The results of these experiments indicate that the native conformation of BlaP197(Gln)55 interferes mainly with the nucleation but not with the elongation step of amyloid fibril formation. Moreover, these results demonstrate that the sequences flanking the polyQ tract significantly influence its propensity to elongate amyloid fibrils. Finally, they clearly indicate that the oligomers of BlaP197(Gln)79 observed at the early stage of the aggregation process are on the pathway of amyloid fibril formation, and likely constitute the aggregation nucleus. [less ▲]

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailInfluence of the protein context on the polyglutamine length-dependent elongation of amyloid fibrils
Huynen, Céline ULg; Willet, Nicolas ULg; Duwez, Anne-Sophie ULg et al

in Biochimica et Biophysica Acta-Proteins and Proteomics (2014)

Detailed reference viewed: 17 (5 ULg)