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 process operating conditions on solvent thermal and oxidative degradation in post-combustion CO2 capture
Léonard, Grégoire ULg; Crosset, Cyril; Toye, Dominique ULg et al

in Computers & Chemical Engineering (in press)

///Document soumis, la révision doit encore être faite./// The CO2 post-combustion capture with amine solvents is modeled as a complex system interconnecting process energy consumption and solvent ... [more ▼]

///Document soumis, la révision doit encore être faite./// The CO2 post-combustion capture with amine solvents is modeled as a complex system interconnecting process energy consumption and solvent degradation and emission. Based on own experimental data, the kinetics of monoethanolamine degradation is included into a model of the CO2 capture process. The influences of operating conditions and flowsheet improvements on solvent loss and process energy requirement are quantified and validated with pilot plant data. Oxidative degradation in the absorber is identified as the major cause of solvent loss. On the contrary, thermal degradation does not appear as a major concern. Finally, this study leads to a decrease by 10% of the process exergy requirement along with a reduction by 11% of the solvent loss, all that by using a single model. Thus, this model provides a practical tool to minimize both the energy requirement and the solvent degradation by the design of large-scale CO2 capture units. [less ▲]

Detailed reference viewed: 28 (7 ULg)
Full Text
Peer Reviewed
See detailInfluence of processing parameters on physicochemical properties of low-trans and trans-free puff pastry margarines
Lefebure, Emilie ULg; Ronkart, Sébastien; Brostaux, Yves ULg et al

in LWT - Food Science and Technology (2013), 51(1), 225-232

Detailed reference viewed: 42 (23 ULg)
Full Text
Peer Reviewed
See detailInfluence of progesterone concentrations on secretory functions of trophoblast and pituitary during the first trimester of pregnancy in dairy cattle
Ayad, A.; Melo de Sousa, Noelita ULg; Sulon, Joseph ULg et al

in Theriogenology (2007), 67(9), 1503-1511

The essential role played by progesterone in the maintenance of pregnancy is unequivocal; however, the effects of progesterone on the secretory patterns of placental and pituitary molecules during the ... [more ▼]

The essential role played by progesterone in the maintenance of pregnancy is unequivocal; however, the effects of progesterone on the secretory patterns of placental and pituitary molecules during the gestation period are not well defined. The objective of this study was to describe pregnancy-associated glycoprotein (PAG) concentrations (measured by RIA-497 and RIA-Pool) in pregnant females with progesterone concentrations lower (low-P4 group, n = 20) or higher (high-P4 group, n = 17) than the mean of 8.74 ng/mL on Day 21 (AI = Day 0). Luteinizing hormone (LH) and prolactin concentrations were also measured in both groups. Throughout the study period, blood samples were collected on Days 0, 21, 45, 60, and 80 from 37 females that were confirmed to be pregnant. PAG concentrations measured by both RIA-497 and RIA-Pool tended to be higher in high-P4 group than in low-P4 group from Day 30 until Day 80. On Day 80, plasma PAG concentrations that were measured using RIA-497 were observed to be higher (P < 0.05) in the high-P4 group than in the low-P4 group (10.2 +/- 8.7 ng/mL versus 6.9 +/- 13.8 ng/mL). Concentrations of LH on Day 60 and prolactin on Day 80 were observed to be significantly lower (P < 0.05) in the high-P4 group. There was a tendency for the concentrations of LH (Days 45 and 80) and prolactin (Days 30, 45, and 60) to be lower in cows in the high-P4 group than in the low-P4 group. Our results suggest the existence of a relationship among the concentration levels of progesterone, PAG, LH, and prolactin during early pregnancy. (C) 2007 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 31 (1 ULg)
Full Text
See detailInfluence of protein context on the propensity of polyglutamine tracts to induce protein aggregation into amyloid fibrils
Huynen, Céline ULg

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 ▲]

Detailed reference viewed: 36 (4 ULg)
Full Text
See detailInfluence of protein context on the propensity of polyglutamine tracts to trigger protein aggregation into amyloid fibrils
Huynen, Céline ULg

Poster (2012, September 10)

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: 50 (6 ULg)
Full Text
Peer Reviewed
See detailInfluence of purified dietary fibre on bacterial protein synthesis in the large intestine of pigs, as measured by the gas production technique.
Bindelle, Jérôme ULg; Buldgen, André; Michaux, David et al

in Livestock Science (2007), 109

Microbial fermentation of non-digestible carbohydrates in the pig's large intestine induces a shift of N excretion from urea in urine to bacterial protein in faeces. Experiments were carried out to ... [more ▼]

Microbial fermentation of non-digestible carbohydrates in the pig's large intestine induces a shift of N excretion from urea in urine to bacterial protein in faeces. Experiments were carried out to measure the mineral N incorporation by the pig intestinal microflora using 5 purified carbohydrates in a gas-test: starch (S), cellulose (C), inulin (I), pectin (P) and xylan (X). Fermentation kinetics was modelled. N source in the buffer solution was replaced by 15N labelled NH4Cl. The bacterial N fixation was determined at mid-fermentation, measuring 15N incorporation into the solid phase of the buffer. The bacterial N fixation was higher (Pb0.001) with I and S (19.9 and 18.1 mg N/g incubated DM), compared to P, C and X (8.7, 5.9 and 5.5 respectively). Inulin and S were fermented also more rapidly, even if I (0.081 h−1) and C (0.074 h−1) showed lower half time fractional rate of degradation than S (0.153 h−1), P (0.133 h−1) and X (0.104 h−1). The insoluble dietary fibre content of the substrates was negatively correlated to bacterial N fixation (r=−0.957, P=0.011). The high crude protein content of P (32.5 mg g−1DM) might explain the lower impact of this substrate on bacterial N fixation, despite its rapid fermentation. Beside the proportion of insoluble fibre, the N content and the rate of fermentation seem to be the major factors influencing bacterial protein synthesis. Further studies including ingredients with variable content of indigestible protein and mean retention time in the pig's intestines are necessary. [less ▲]

Detailed reference viewed: 47 (12 ULg)
Full Text
Peer Reviewed
See detailInfluence of residual alpha-amylase activity on the pasting properties of extracted wheat starch.
Lenartz, Jonathan; Sinnaeve, Georges; Massaux, Carine et al

Poster (2005, June)

Detailed reference viewed: 15 (0 ULg)
Full Text
Peer Reviewed
See detailInfluence of response factors on determining equilibrium association constants of non-covalent complexes by electrospray ionization mass spectrometry
Gabelica, Valérie ULg; Galic, Nives; Rosu, Frédéric ULg et al

in Journal of Mass Spectrometry [=JMS] (2003), 38(5), 491-501

A method for determining the equilibrium association constant of a complexation reaction A + B <=> AB by electrospray ionization mass spectrometry is described. The method consists in measuring the ... [more ▼]

A method for determining the equilibrium association constant of a complexation reaction A + B <=> AB by electrospray ionization mass spectrometry is described. The method consists in measuring the relative intensities of the peaks corresponding to A and to AB in equimolar A–B solutions at different concentrations C0. The results are fitted by a non-linear least-squares procedure, with the two variable parameters being the equilibrium association constant Ka and a factor R, defined by I(AB)/I.A/ = R× [AB]/[A]. The factor R is the ratio between the response factors of AB and A, and corrects for the relative electrospray responses of the complex and the free substrate A, mass discrimination of instrumental origin and/or moderate in-source dissociation. The method is illustrated with the following two systems: complexes between a double-stranded 12-base pair oligonucleotide and minor groove binders, and cyclodextrin complexeswith a,!-dicarboxylic acids. For the oligonucleotide complexes, it is found that the response of the complex is not dramatically different to the response of the free oligonucleotide duplex, as the double helix conformation is disturbed by the drug only to a minor extent. In the case of cyclodextrin complexes, these complexes were found to have a much higher response than free cyclodextrin. This may be due to the fact that cyclodextrin is neutral in solution, whereas the complex is charged, but it can also stem from the fact that a significant proportion of the complex is in a non-inclusion geometry. The present method requires the exact determination of the concentrations of the reactants and is applicable to 1 : 1 complexes. [less ▲]

Detailed reference viewed: 63 (5 ULg)
Full Text
Peer Reviewed
See detailInfluence of response prepotency strength, general working memory resources, and specific working memory load on the ability to inhibit predominant responses: A comparison of young and elderly participants
Grandjean, Julien ULg; Collette, Fabienne ULg

in Brain & Cognition (2011), 77

One conception of inhibitory functioning suggests that the ability to successfully inhibit a predominant response depends mainly on the strength of that response, the general functioning of working memory ... [more ▼]

One conception of inhibitory functioning suggests that the ability to successfully inhibit a predominant response depends mainly on the strength of that response, the general functioning of working memory processes, and the working memory demand of the task (Roberts, Hager, and Heron, 1994). The proposal that inhibition and functional working memory capacity interact was assessed in the present study using two motor inhibition tasks (Go/No-Go and response incompatibility) in young and older participants. The strength of prepotency was assessed with a short or long training phase for the response to be inhibited. The influence of working memory resources was evaluated by administering the tasks in full versus divided attention conditions. The effect of working memory load was manipulated by increasing the number of target and distracter items in each task. Results showed no effect of prepotency strength, whereas dividing attentional resources and increasing working memory load were associated with greater inhibitory effects in both groups and for both tasks. This deleterious effect was higher for older participants, except in the working memory load condition of the Go/No-Go task. These results suggest an interactive link between working memory and response inhibition by showing that taxing working memory resources increases the difficulty of inhibiting prepotent responses in younger and older subjects. The additional detrimental effect of these factors on healthy elderly subjects was related to their decreased cognitive resources and to their shorter span size. [less ▲]

Detailed reference viewed: 44 (7 ULg)
Peer Reviewed
See detailInfluence of rhizobacterial volatile compounds on growth and root system architecture of Brachypodium distachyon (L.) Beauv.
Mendaluk, Magdalena ULg; Varin, Sébastien; Baudson, Caroline ULg et al

Poster (2013, February 08)

Many rhizobacterial strains are classified as plant growth-promoting rhizobacteria (PGPR) and are potentially useful to enhance plant fitness and productivity. Among the mechanisms by which PGPR improve ... [more ▼]

Many rhizobacterial strains are classified as plant growth-promoting rhizobacteria (PGPR) and are potentially useful to enhance plant fitness and productivity. Among the mechanisms by which PGPR improve plant growth, the emission of volatile organic compounds (VOCs) and their biological impacts on plants remain little documented. The aim of this work is to evaluate the growth promotion ability of 19 bacterial strains on the model grass Brachypodium distachyon Bd21 (Bd21), with a focus on this peculiar mode of interaction. A collection of 19 strains was selected for their known growth promotion potential. The impact of the rhizobacteria on the model grass was studied using an in vitro cocultivation system allowing interactions through VOCs without physical contact between plants and bacteria. The results show that the VOCs of several strains promote total biomass production, modulate biomass partitioning and affect shoot and root architecture of Bd21. The effects of the PGPR strains emitting different volatile blends were investigated via principal component analysis coupled to clustering and univariate analysis to unravel their biological effects. On the basis of volatile emissions and of their effects on plant growth, two strains have been selected in order to evaluate such interactions using an ex vitro system. The set-up of this system is in progress. [less ▲]

Detailed reference viewed: 75 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence of rhizosphere-specific parameters on surfactin production by Bacillus subtilis.
Ongena, MARC ULg; Nihorimbere, Venant; Fickers, Patrick ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2009), (43), 317-320

Detailed reference viewed: 66 (16 ULg)
Peer Reviewed
See detailInfluence of rhizosphere-specific parameters on surfactin production by Bacillus subtilis.
Nihorimbere, V.; Fickers, Patrick ULg; Thonart, Philippe ULg et al

Conference (2008, September)

Detailed reference viewed: 17 (5 ULg)
Full Text
Peer Reviewed
See detailInfluence of salt restriction in untreated essential hypertension patients
Krzesinski, Jean-Marie ULg; Du, F.; Pequeux, L. et al

in Journal of Hypertension (1992), 10(10), 1297-1298

Detailed reference viewed: 4 (0 ULg)