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See detailThe Critical Neighbourhood Range for Asymptotic Overlay Connectivity in Dense Ad Hoc Networks
Calomme, Sandrine; Leduc, Guy ULiege

in Challenges in Ad Hoc Networking (2005, June)

We define, for an overlay built on top of an ad hoc network, a simple criterion for neighbourhood: two overlay nodes are neighbours if and only if there exists a path between them of at most R hops, and R ... [more ▼]

We define, for an overlay built on top of an ad hoc network, a simple criterion for neighbourhood: two overlay nodes are neighbours if and only if there exists a path between them of at most R hops, and R is called the (overlay) neighbourhood range. A small R may result in a disconnected overlay, while an unnecessarily large R would generate extra control traffic. We are interested in the minimum R ensuring overlay connectivity, the so-called critical R. We derive a necessary and sufficient condition on R to achieve asymptotic connectivity of the overlay almost surely, i.e. connectivity with probability 1 when the number of overlay nodes tends to infinity, under the hypothesis that the underlying ad hoc network is itself asymptotically almost surely connected. This condition, though asymptotic, sheds some light on the relation linking the critical R to the number of nodes n, the normalized radio transmission range r and the overlay density D (i.e., the proportion of overlay nodes). This condition can be considered as an approximation when the number of nodes is large enough. Since r is considered as a function of n, we are able to study the impact of topology control mechanisms, by showing how the shape of this function impacts the critical R. [less ▲]

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See detailCritical opalescence points to thermodynamic instability:relevance to small-angle X-ray scattering of resorcinol–formaldehyde gel formation at low pH
Gommes, Cédric ULiege; Job, Nathalie ULiege; Pirard, Jean-Paul ULiege et al

in Journal of Applied Crystallography (2008), 41(4), 663-668

During the formation at low pH of resorcinol–formaldehyde gels with a structure in the micrometre range, small-angle X-ray scattering exhibits a nonmonotonic intensity variation as a function of reaction ... [more ▼]

During the formation at low pH of resorcinol–formaldehyde gels with a structure in the micrometre range, small-angle X-ray scattering exhibits a nonmonotonic intensity variation as a function of reaction time. The data are analyzed in terms of scattering by statistical fluctuations of polymer concentration, the amplitude of which is maximal close to the critical point for phase separation between polymer and solvent. The data do not carry any morphological information, but they unambiguously show that the driving force of the gel formation is a thermodynamic instability of the polymerizing solution. [less ▲]

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See detailCritical parameters for the partial coalescence of a droplet
Gilet, Tristan ULiege; Mulleners, Karen; Lecomte, Jean-Paul et al

in Physical Review E (2007), 75(3, Pt 2), 36303

The partial coalescence of a droplet onto a planar liquid-liquid interface is investigated experimentally by tuning the viscosities of both liquids. The problem mainly depends on four dimensionless ... [more ▼]

The partial coalescence of a droplet onto a planar liquid-liquid interface is investigated experimentally by tuning the viscosities of both liquids. The problem mainly depends on four dimensionless parameters: The Bond number (gravity vs surface tension), the Ohnesorge numbers (viscosity in both fluids vs surface tension), and the density relative difference. The ratio between the daughter droplet size and the mother droplet size is investigated as a function of these dimensionless numbers. Global quantities such as the available surface energy of the droplet have been measured during the coalescence. The capillary waves propagation and damping are studied in detail. The relation between these waves and the partial coalescence is discussed. Additional viscous mechanisms are proposed in order to explain the asymmetric role played by both viscosities. [less ▲]

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See detailCritical parameters in deriving fire fragility functions for steel gravity frames
Gernay, Thomas ULiege; Elhami Khorasani, Negar; Garlock, Maria

in Garlock, Maria; Kodur, Venkatesh (Eds.) Structures in Fire (Proceedings of the Ninth International Conference) (2016, June 10)

Fire fragility functions can be used to characterize the probabilistic vulnerability of buildings to fire in the context of urban resilience assessment. A methodology has been proposed to develop such ... [more ▼]

Fire fragility functions can be used to characterize the probabilistic vulnerability of buildings to fire in the context of urban resilience assessment. A methodology has been proposed to develop such functions for multi-story steel buildings. However, a large number of parameters with uncertainties play a role in the process of constructing the fragility functions. The goal of this research is to identify the critical parameters that most affect the global fire safety by investigating the sensitivity of the fragility functions to different input parameters. Sensitivity in parameters affecting the fire model, the heat transfer process and the thermo-mechanical response is examined. The effects of different design assumptions at the system level are also studied. The presented approach is useful for selecting the prevailing parameters in a fire reliability analysis and it provides important information for modeling tools that can be used to evaluate resilience for fire scenarios. [less ▲]

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See detailCritical periods and critical values explaining fluxes inter-annual variability in a temperate mixed forest
Hurdebise, Quentin ULiege; Vincke, Caroline; De Ligne, Anne ULiege et al

Poster (2015, June 04)

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the ... [more ▼]

In order to explain inter-annual variability of Net Ecosystem CO2 Exchange (NEE) above a mixed temperate forest, two approaches were followed: •Detection of critical periods using the R-squared of the regression between annual NEE and cumulated NEE on a mobile window. •Identification of critical values of a threshold used to decompose annual and seasonal NEE in two components. [less ▲]

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See detailCritical points and reaction paths characterization on a potential energy hypersurface
Ramquet, Marie-Noëlle; Dive, Georges ULiege; Dehareng, Dominique ULiege

in Journal of Chemical Physics (2000), 112(11), 4923-4934

Most of the time, the definitions of minima, saddle points or more generally order p (p=0,...,n) critical points, do not mention the possibility of having zero Hessian eigenvalues. This feature reflects ... [more ▼]

Most of the time, the definitions of minima, saddle points or more generally order p (p=0,...,n) critical points, do not mention the possibility of having zero Hessian eigenvalues. This feature reflects some flatness of the potential energy hypersurface in a special eigendirection which is not often taken into account. Thus, the definitions of critical points are revisited in a more general framework within this context. The concepts of bifurcation points, branching points, and valley ridge inflection points are investigated. New definitions based on the mathematical formulation of the reaction path are given and some of their properties are outlined. (C) 2000 American Institute of Physics. [S0021-9606(00)01110-7]. [less ▲]

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See detailCritical points for Salmonella contamination during slaughter process in Belgian slaughterhouses.
De Saedeleer, L.; Maes, D.; Dewulf, J. et al

in International Pig Veterinary Society Congress (2006, July)

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See detailCritical points in glucosinolates analysis in seed and plant tis Critical points in glucosinolates analysis in seed and plant tissues by HPLC of desulfo-derivatives
Leoni, O.; Iori, R.; Wathelet, Jean-Paul ULiege et al

Poster (2004)

In the EU the ISO 9167-1 is the reference method for glucosinolates content determination in rapeseed. This method is widely used also for other seeds or Brassica plant tissues analysis also in order to ... [more ▼]

In the EU the ISO 9167-1 is the reference method for glucosinolates content determination in rapeseed. This method is widely used also for other seeds or Brassica plant tissues analysis also in order to the large diffusion of HPLC instrumentation in analytical laboratories. Anyway, in our experience the use of this method has revealed some critical points which can considerably affect the final result, thus when this method is used to analyse materials different from seeds of B. napus some methodological modifications must be done especially in reason of the kind of glucosinolate present in the sample. [less ▲]

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See detailCritical Re-Examination of the Distribution of Aromatase-Immunoreactive Cells in the Quail Forebrain Using Antibodies Raised against Human Placental Aromatase and against the Recombinant Quail, Mouse or Human Enzyme
Foidart, Agnès ULiege; Reid, J.; Absil, Philippe ULiege et al

in Journal of Chemical Neuroanatomy (1995), 8(4), 267-82

Mouse and quail aromatase cDNAs were isolated from libraries of mouse ovary and quail brain by using a human aromatase cDNA fragment (hA-24) as a probe. These three cDNAs were inserted into plasmid ... [more ▼]

Mouse and quail aromatase cDNAs were isolated from libraries of mouse ovary and quail brain by using a human aromatase cDNA fragment (hA-24) as a probe. These three cDNAs were inserted into plasmid vectors and expressed in Escherichia coli. Antisera against these purified recombinant proteins were raised in rabbit and purified by ammonium sulfate fractionation and affinity chromatography. The three antibodies directed against recombinant human, mouse and quail proteins were used to visualize aromatase-immunoreactive cells in the quail brain. They were compared with the antibody raised against human placental aromatase used in previous experiments and with another antibody recently developed by similar methods. The signal obtained with all antibodies was completely abolished by preadsorption with the homologous recombinant antigens and the signal produced by the two antibodies raised against placental aromatase was similarly abolished by a preadsorption with recombinant quail aromatase. The antibodies raised against recombinant proteins identified the major groups of aromatase cells previously described in the quail brain. The antibodies directed against the mouse and quail antigen identified more positive cells and stained them more densely than the antibodies raised against human recombinant antigen or purified placental aromatase. The new cell groups identified by the antibody raised against quail recombinant aromatase were located in an area ventral to the fasciculus prosencephali lateralis, the nucleus accumbens, the paleostriatum ventrale, the nucleus taeniae, the area around the nucleus ovoidalis, the caudal tuber and the mesencephalic central gray. A critical re-examination of the distribution and nomenclature of the aromatase-positive cells is proposed based on these new findings. [less ▲]

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See detailCritical Reflections on the Treaty on the Non-Proliferation of Nuclear Weapons
Michel, Quentin ULiege

in Nuclear Law Bulletin (2007)

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See detailCritical Review of Near-Infrared Spectroscopic Methods Validations in Pharmaceutical Applications
De Bleye, Charlotte ULiege; Chavez, Pierre-François ULiege; Mantanus, Jérôme ULiege et al

in Journal of Pharmaceutical & Biomedical Analysis (2012), 69

Based on the large number of publications reported over the past five years, near-infrared spectroscopy (NIRS) is more and more considered an attractive and promising analytical tool regarding Process ... [more ▼]

Based on the large number of publications reported over the past five years, near-infrared spectroscopy (NIRS) is more and more considered an attractive and promising analytical tool regarding Process Analytical Technology and Green Chemistry. From the reviewed literature, few of these publications present a thoroughly validated NIRS method even if some guidelines have been published by different groups and regulatory authorities. However, as any analytical method, the validation of NIRS method is a mandatory step at the end of the development in order to give enough guarantees that each of the future results during routine use will be close enough to the true value. Besides the introduction of PAT concepts in the revised document of the European Pharmacopoeia (2.2.40) dealing with near-infrared spectroscopy recently published in Pharmeuropa, it agrees very well with this mandatory step. Indeed, the latter suggests to use similar analytical performance characteristics than those required for any analytical procedure based on acceptance criteria consistent with the intended use of the method. In this context, this review gives a comprehensive and critical overview of the methodologies applied to assess the validity of quantitative NIRS methods used in pharmaceutical applications. [less ▲]

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See detailCritical review of surface-enhanced Raman spectroscopy applications in the pharmaceutical field
Cailletaud, Johan ULiege; De Bleye, Charlotte ULiege; Dumont, Elodie ULiege et al

in Journal of Pharmaceutical & Biomedical Analysis (2018), 147

Surface-enhanced Raman spectroscopy (SERS) is a sensitive analytical tool used in the pharmaceutical field in recent years. SERS keeps all the advantages of classical Raman spectroscopy while being is ... [more ▼]

Surface-enhanced Raman spectroscopy (SERS) is a sensitive analytical tool used in the pharmaceutical field in recent years. SERS keeps all the advantages of classical Raman spectroscopy while being is more sensitive allowing its use for the detection and the quantification of low-dose substances contained in pharmaceutical samples. However, the analytical performance of SERS is limited due to the difficulty to implement a quantitative methodology correctly validated. Nevertheless, some studies reported the development of SERS quantitative methods especially in pharmaceutical approaches. In this context, this review presents the main concepts of the SERS technique. The different steps that need to be applied to develop a SERS quantitative method are also deeply described. The last part of the present manuscript gives a critical overview of the different SERS pharmaceutical applications that were developed for a non-exhaustive list of pharmaceutical compounds with the aim to highlights the validation criteria for each application. [less ▲]

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See detailA critical review of surgery techniques for implanting telemetry devices into the body cavity of fish
Baras, Etienne; Birtles, Cymon; Westerloppe, Luc et al

Conference (1996, August)

Based on literature survey and personal experience, this paper presents a critical review of surgery procedures to implant telemetry devices (transmitters, transponders) into the body cavity of fish ... [more ▼]

Based on literature survey and personal experience, this paper presents a critical review of surgery procedures to implant telemetry devices (transmitters, transponders) into the body cavity of fish species. It debates on the relative adequacy of techniques which may compromise or enhance tagging success with respect to fish health and transmitter retention: anaesthesia, incision (position and length of incision), transmitter features (size and weight ratios, coating), ways of closing the incision (stitches, staples, adhesives), prophylaxy, pre- and postoperative care. Behavioural and physiological biases originating from tagging or internal presence of the transmitter are reviewed, evaluated and integrated to determine the actual duration of the post-operative perturbation and subsequent validation of telemetry data. [less ▲]

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See detailA Critical Review of the Application of Drop-Population Balances for the Design of Solvent Extraction Columns: I. Concept of Solving Drop-Population Balances and Modelling Breakage and Coalescence
Kopriwa, Nicole; Buchbender, Florian; Ayesterán, José et al

in Solvent Extraction & Ion Exchange (2012), 30(7), 683-723

Detailed reference viewed: 40 (13 ULiège)
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See detailThe critical role of carbohydrate administration in safe, effective TGC
PREISER, Jean-Charles ULiege; Suhaimi, F; Chase, JG et al

in Clinical Nutrition (2010), 5 (Suppl 2):111

Detailed reference viewed: 16 (2 ULiège)
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See detailCritical role of oxygen photoreduction downstream of PSI in Symbiodinium: photoprotection, energetic adjustement and ROS production
Roberty, Stéphane ULiege; Bailleul, Benjamin; Berne, Nicolas ULiege et al

Conference (2015, August)

The ecological success of symbiotic cnidarians (reef building-corals and sea anemones) relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium ... [more ▼]

The ecological success of symbiotic cnidarians (reef building-corals and sea anemones) relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium. Photosynthetic organisms have evolved various photoprotective and regulatory mechanisms to cope with changing and high light intensities, but the nature and relative amplitude of these mechanisms is still a matter of debate in Symbiodinium. Few studies showed that molecular oxygen (O2) can be an efficient electron sink during photosynthesis in Symbiodinium, with an O2 uptake capacity that could represent up to half the maximum O2 evolution. In addition, members of clade A Symbiodinium were proposed to possess enhanced capabilities for alternative photosynthetic electron flows. In this work, the amplitude of photosynthetic alternative electron flows to oxygen (chlororespiration, Mehler reaction, mitochondrial respiration) and PSI cyclic electron flow were investigated in Symbiodinium strains belonging to different Clades (A, B and F). Joint measurements of oxygen evolution, PSI and PSII activities allowed us to demonstrate that photoreduction of oxygen downstream PSI by the so-called Mehler reaction is the main alternative electron sink at the onset and steady state of photosynthesis in all strains1. This mechanism in Symbiodinium sustains significant photosynthetic electron flux under high light, thus acting as a photoprotective mechanism and modifying the ratio of ATP/NADPH to match the requirements of carbon reduction. At higher temperature (26 to 33°C), the amplitude of Mehler reaction was still significantly increased but the capacity of enzymes responsible for superoxide detoxification largely decreased. This imbalance generated twice more ROS than during the treatment at 26°C, suggesting that under conditions known to induce coral bleaching, the photoprotective role of Mehler reaction can no longer be maintained, at least at short term. [less ▲]

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See detailCritical role of oxygen photoreduction downstream of PSI in Symbiodinium: photoprotection, energetic adjustement and ROS production
Cardol, Pierre ULiege

Conference (2015)

The ecological success of symbiotic cnidarians (reef corals and anemones) relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium. Photosynthetic organisms ... [more ▼]

The ecological success of symbiotic cnidarians (reef corals and anemones) relies on the symbiosis between cnidarians and photosynthetic dinoflagellates of the genus Symbiodinium. Photosynthetic organisms have evolved various photoprotective and regulatory mechanisms to cope with changing and high light intensities, but the nature and relative amplitude of these mechanisms is still a matter of debate in Symbiodinium. Few studies showed that molecular oxygen (O2) can be an efficient electron sink during photosynthesis in Symbiodinium, with an O2 uptake capacity that could represent up to half the maximum O2 evolution. In addition, members of clade A Symbiodinium were proposed to possess enhanced capabilities for alternative photosynthetic electron flows. In this work, the amplitude of photosynthetic alternative electron flows to oxygen (chlororespiration, Mehler reaction, mitochondrial respiration) and PSI cyclic electron flow were investigated in Symbiodinium strains belonging to different Clades (A, B and F). Joint measurements of oxygen evolution, PSI and PSII activities allowed us to demonstrate that photoreduction of oxygen downstream PSI by the so-called Mehler reaction is the main alternative electron sink at the onset and steady state of photosynthesis in all strains1. This mechanism in Symbiodinium sustains significant photosynthetic electron flux under high light, thus acting as a photoprotective mechanism and modifying the ratio of ATP/NADPH to match the requirements of carbon reduction. At higher temperature (26 to 33°C), the amplitude of Mehler reaction was still significantly increased but the capacity of enzymes responsible for superoxide detoxification largely decreased. This imbalance generated twice more ROS than during the treatment at 26°C, suggesting that under environmental conditions leading to coral bleaching, the photoprotective role of Mehler reaction can no longer be maintained. [less ▲]

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See detailA critical role of plastidial glycolytic glyceraldehyde-3-phosphate dehydrogenase in the control of plant metabolism and development
Muñoz-Bertomeu, Jesús; Cascales - Miñana, Borja ULiege; Alaiz, Manuel et al

in Plant Signaling & Behavior (2010), 5(1), 67-69

Glycolysis is a central metabolic pathway that provides energy and generates precursors for the synthesis of primary metabolites such as amino acids and fatty acids.1-3 In plants, glycolysis occurs in the ... [more ▼]

Glycolysis is a central metabolic pathway that provides energy and generates precursors for the synthesis of primary metabolites such as amino acids and fatty acids.1-3 In plants, glycolysis occurs in the cytosol and plastids, which complicates the understanding of this essential process.1 As a result, the contribution of each glycolytic pathway to the specific primary metabolite production and the degree of integration of both pathways is still unresolved. The glycolytic glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate. Both cytosolic (GAPCs) and plastidial (GAPCps) GAPDH activities have been described biochemically. But, up to now, little attention had been paid to GAPCps, probably because they have been considered as "minor isoforms" that catalyze a reversible reaction in plastids where it has been assumed that key glycolytic intermediates are in equilibrium with the cytosol. In the associated study,4 we have elucidated the crucial role of Arabidopsis GAPCps in the control of primary metabolism in plants. GAPCps deficiency affects amino acid and sugar metabolism and impairs plant development. Specifically, GAPCp deficiency affects the serine supply to roots, provoking a drastic phenotype of arrested root development. Also, we show that the phosphorylated serine biosynthesis pathway is critical to supply serine to non-photosynthetic organs such as roots. These studies provide new insights of the contribution of plastidial glycolysis to plant metabolism and evidence the complex interactions existing between metabolism and development. © 2010 Landes Bioscience. [less ▲]

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See detailCritical role of tryptophan 154 for the activity and stability of class D beta-lactamases.
Baurin, Stephane; Vercheval, Lionel ULiege; Bouillenne, Fabrice ULiege et al

in Biochemistry (2009), 48(47), 11252-63

The catalytic efficiency of the class D beta-lactamase OXA-10 depends critically on an unusual carboxylated lysine as the general base residue for both the enzyme acylation and deacylation steps of ... [more ▼]

The catalytic efficiency of the class D beta-lactamase OXA-10 depends critically on an unusual carboxylated lysine as the general base residue for both the enzyme acylation and deacylation steps of catalysis. Evidence is presented that the interaction between the indole group of Trp154 and the carboxylated lysine is essential for the stability of the posttranslationally modified Lys70. Substitution of Trp154 by Gly, Ala, or Phe yielded noncarboxylated enzymes which displayed poor catalytic efficiencies and reduced stability when compared to the wild-type OXA-10. The W154H mutant was partially carboxylated. In addition, the maximum values of k(cat) and k(cat)/K(M) were shifted toward pH 7, indicating that the carboxylation state of Lys70 is dependent on the protonation level of the histidine. A comparison of the three-dimensional structures of the different proteins also indicated that the Trp154 mutations did not modify the overall structures of OXA-10 but induced an increased flexibility of the Omega-loop in the active site. Finally, the deacylation-impaired W154A mutant was used to determine the structure of the acyl-enzyme complex with benzylpenicillin. These results indicate a role of the Lys70 carboxylation during the deacylation step and emphasize the importance of Trp154 for the ideal positioning of active site residues leading to an optimum activity. [less ▲]

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