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See detailSingle-beat evaluation of right ventricular contractility - Reply
Lambermont, Bernard ULg; Segers, P.; D'Orio, Vincenzo ULg

in Critical Care Medicine (2005), 33(4), 918-918

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See detailTree-based batch mode reinforcement learning
Ernst, Damien ULg; Geurts, Pierre ULg; Wehenkel, Louis ULg

in Journal of Machine Learning Research (2005), 6

Reinforcement learning aims to determine an optimal control policy from interaction with a system or from observations gathered from a system. In batch mode, it can be achieved by approximating the so ... [more ▼]

Reinforcement learning aims to determine an optimal control policy from interaction with a system or from observations gathered from a system. In batch mode, it can be achieved by approximating the so-called Q-function based on a set of four-tuples (x(t), u(t), r(t), x(t+1)) where x(t) denotes the system state at time t, u(t) the control action taken, r(t) the instantaneous reward obtained and x(t+1) the successor state of the system, and by determining the control policy from this Q-function. The Q-function approximation may be obtained from the limit of a sequence of (batch mode) supervised learning problems. Within this framework we describe the use of several classical tree-based supervised learning methods (CART, Kd-tree, tree bagging) and two newly proposed ensemble algorithms, namely extremely and totally randomized trees. We study their performances on several examples and find that the ensemble methods based on regression trees perform well in extracting relevant information about the optimal control policy from sets of four-tuples. In particular, the totally randomized trees give good results while ensuring the convergence of the sequence, whereas by relaxing the convergence constraint even better accuracy results are provided by the extremely randomized trees. [less ▲]

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See detailL'ischemie aigue des membres: aspects cliniques, diagnostiques et therapeutiques
Van Damme, Hendrik ULg; Limet, Raymond ULg

in Revue Médicale de Liège (2005), 60(4), 247-54

Acute lower limb ischemia, with sudden interruption of tissue perfusion, is a medico-surgical emergency. An early diagnosis is a prerequisite for optimal management. Diagnosis is mainly based on clinical ... [more ▼]

Acute lower limb ischemia, with sudden interruption of tissue perfusion, is a medico-surgical emergency. An early diagnosis is a prerequisite for optimal management. Diagnosis is mainly based on clinical data. Complementary investigations have a limited place, and should not unnecessarily delay the treatment. There are two categories of acute arterial, non-traumatic occlusion: embolism and thrombosis of an atherosclerotic vessel. The distinction between these two entities is not always evident, since ischemia can be the consequence of an arterial embolism in a diseased atherosclerotic artery. We discuss the clinical aspects and the causes of acute lower limb ischemia. The prognosis, outcome and therapeutic management are determined by the cause of the acute arterial obliteration. [less ▲]

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See detailD-Hormone analog alfacalcidol: an update on its role in post-menopausal osteoporosis and rheumatoid arthritis management
Richy, F.; Deroisy, Rita ULg; Lecart, Marie-Paule ULg et al

in Aging Clinical & Experimental Research (2005), 17(2), 133-142

Alfacalcidol (1-alpha-hydroxyvitamin D is a non-endogenous analog of vitamin D which can bypass the renal and intestinal regulatory mechanisms that control the production of calcitriol (1,25 ... [more ▼]

Alfacalcidol (1-alpha-hydroxyvitamin D is a non-endogenous analog of vitamin D which can bypass the renal and intestinal regulatory mechanisms that control the production of calcitriol (1,25-hydroxyvitamin D-3, the active form of vitamin D, D-Hormone). Alfiacalcidol may be metabolized into calcitriol with a limited risk of hypercalcemia. Alfacalcidol and calcitriol have been evaluated in animal and human studies assessing their effects on bone mineral density and fracture rates. More recently, they have been shown to produce beneficial effects in muscle, immune system, and autoimmune diseases, including rheumatoid arthritis. This paper discusses the therapeutic efficacy of alfacalcidol in reports in which it has been proposed as an interesting alternative to vitamin D or calcitriol. Some recent findings about general metabolism and regulation of vitamin D and its analogs are discussed. The biological and clinical effects of alfacalcidol in post-menopausal osteoporosis are reviewed, followed by critical appraisal of its efficacy in preventing bone loss and falls in the elderly. The lost two sections discuss the role of Danalogs in regulating the immune system, with particular regard to rheumatoid arthritis. The main results of this review show that alfacalcidol may have a wider range of therapeutic applicability, beyond simply restricting it to patients in hemodialysis or peritoneal dialysis with high serum levels of intact PTH. (c) 2005, Editrice Kurtis. [less ▲]

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See detailHigh-resolution diatom/clay record in Lake Baikal from grey scale, and magnetic susceptibility over Holocene and Termination I
Boes, Xavier; Piotrowska, Natalia; Fagel, Nathalie ULg

in Global and Planetary Change (2005), 46(1-4), 299-313

Tracing past climate signals from Lake Baikal sediments with a "multi-annual' resolution by conventional techniques is a difficult challenge since the sedimentation rates from Termination I up to the ... [more ▼]

Tracing past climate signals from Lake Baikal sediments with a "multi-annual' resolution by conventional techniques is a difficult challenge since the sedimentation rates from Termination I up to the present range from 0.004 to 0.17 mm/year. In this paper, climate signals are reconstructed from three continuous sediment records from Vydrino Shoulder and Posolsky Bank in the Southern Basin, and Continent Ridge in the Northern Basin. For each coring site, a calendar age model was constructed using calibrated radiocarbon ages. The magnetic susceptibility is used to better constrain the age models over OIS4 to OIS1 The cores have been hardened using polymerized technique in order to allow the easy cut of thin sections that contain evidence for narrow biogenic/clayey laminations. The grey scale taken from the thin sections is used here as a high-resolution proxy record of diatom/clay ratio. The grey density values are qualitatively interpreted against the sediment components by optical microscopy from the thin sections. In the Northern Basin, the Continent station provides the best age model and sediment resolution over the Termination I period. In particular, four optima (i.e. Bolling, Allerod, Atlantic, and Subboreal) are indicated by substantial increases of the grey scale, whereas cold periods like the Younger Dryas correspond to lower grey scale values. We emphasize that the short-term variations in the grey scale at 20 mu m resolution could correspond to short climate responses in Lake Baikal sediments. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailL'hyperkaliemie, ce nouveau tueur?
Krzesinski, Jean-Marie ULg

in Revue Médicale de Liège (2005), 60(4), 222-6

Hyperkalemia is now commonly observed due to several associated factors such as old age, diabetes, congestive heart failure, renal insufficiency and drugs such as spironolactone used to improve cardiac ... [more ▼]

Hyperkalemia is now commonly observed due to several associated factors such as old age, diabetes, congestive heart failure, renal insufficiency and drugs such as spironolactone used to improve cardiac function. Moreover, the easily prescribed new antiinflammatory drugs COX2 selective inhibitors in these patients lead to a very acute risk for vital hyperkalemia development. This review insists on the prevention of such potentially reversible disorder. [less ▲]

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See detailArray of microsystem for live monitoring of high voltage power lines
Renson, Luc ULg; Jamar, Claude ULg; Guérard, Suzanne ULg et al

in Proceedings of the 1st IOMAC (2005, April)

How to use microsystems placed on power lines environment.

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See detailAnti-tumor effect of caveolin gene delivery are mediated through the inhibition of the pro-angiogenic and vasodilatating effect of nitric oxide
Brouet, A.; DeWever, Julie; MARTINIVE, Philippe ULg et al

in FASEB Journal (2005)

In tumors, caveolin-1, the structural protein of caveolae, constitutes a key switch through its function as a tumor suppressor and a promoter of metastases. In endothelial cells (EC), caveolin is also ... [more ▼]

In tumors, caveolin-1, the structural protein of caveolae, constitutes a key switch through its function as a tumor suppressor and a promoter of metastases. In endothelial cells (EC), caveolin is also known to directly interact with the endothelial nitric oxide synthase (eNOS) and thereby to modulate nitric oxide (NO)-mediated processes including vasodilation and angiogenesis. In this study, we examined whether the modulation of the stoichiometry of the caveolin/eNOS complex in EC lining tumor blood vessels could affect the tumor vasculature and consecutively tumor growth. For this purpose, we used cationic lipids, which are delivery systems effective at targeting tumor vs. normal vascular networks. We first documented that in vitro caveolin transfection led to the inhibition of both VEGF-induced EC migration and tube formation on Matrigel. The DNA-lipocomplex was then administered through the tail vein of tumor-bearing mice. The direct interaction between recombinant caveolin and native eNOS was validated in coimmunoprecipitation experiments from tumor extracts. A dramatic tumor growth delay was observed in mice transfected with caveolin- vs. sham-transfected animals. Using laser Doppler imaging and microprobes, we found that in the early time after lipofection (e.g., when macroscopic effects on the integrity of the tumor vasculature were not detectable), caveolin expression impaired NO-dependent tumor blood flow. At later stages post-transfection, a decrease in tumor microvessel density in the central core of caveolin-transfected tumors was also documented. In conclusion, our study reveals that by exploiting the exquisite regulatory interaction between eNOS and caveolin and the propensity of cationic lipids to target EC lining tumor blood vessels, caveolin plasmid delivery appears to be a safe and efficient way to block neoangiogenesis and vascular function in solid tumors, independently of any direct effects on tumor cells. [less ▲]

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See detailQuantification of lipid bilayer effective microviscosity and fluidity effect induced by propofol
Bahri, Mohamed Ali ULg; Heyne, Belinda; Hans, Pol ULg et al

in Biophysical Chemistry (2005), 114(1), 53-61

Electron spin resonance (ESR) spectroscopy with nitroxide spin probes was used as a method to probe the liposome microenvironments. The effective microviscosities have been determined from the calibration ... [more ▼]

Electron spin resonance (ESR) spectroscopy with nitroxide spin probes was used as a method to probe the liposome microenvironments. The effective microviscosities have been determined from the calibration of the ESR spectra of the probes in solvent mixtures of known viscosities. In the first time, by measuring ESR order parameter (S ) and correlation time (s c) of stearic spin probes, we have been able to quantify the value of effective microviscosity at different depths inside the liposome membrane. At room temperature, local microviscosities measured in dimyristoyl-l-a phosphatidylcholine (DMPC) liposome membrane at the different depths of 7.8, 16.95, and 27.7 2 were 222.53, 64.09, and 62.56 cP, respectively. In the gel state (10 °C), those microviscosity values increased to 472.56, 370.61, and 243.37 cP. In a second time, we have applied this technique to determine the modifications in membrane microviscosity induced by 2,6-diisopropyl phenol (propofol; PPF), an anaesthetic agent extensively used in clinical practice. Propofol is characterized by a unique phenolic structure, absent in the other conventional anaesthetics. Indeed, given its lipophilic property, propofol is presumed to penetrate into and interact with membrane lipids and hence to induce changes in membrane fluidity. Incorporation of propofol into dimyristoyl-L-alpha-phosphatidylcholine liposomes above the phase-transition temperature (23.9 °C) did not change microviscosity. At 10 °C, an increase of propofol concentration from 0 to 1.0 10 [less ▲]

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See detailMobility prediction's influence on QoS in wireless networks: a study on a call admission algorithm
François, Jean-Marc; Leduc, Guy ULg

(2005, April)

Several mechanisms increase the QoS level of mobile networks thanks to an underlying mobility prediction method (i.e. a means to predict a mobile's next access router). This paper aims at studying how the ... [more ▼]

Several mechanisms increase the QoS level of mobile networks thanks to an underlying mobility prediction method (i.e. a means to predict a mobile's next access router). This paper aims at studying how the accuracy of the prediction method can influence the network QoS in the particular context of call admission control. It shows that (a) the mobiles behaviour must be adapted according to the prediction scheme accuracy in order to achieve good performance and (b) the admission algorithm can be modified to increase its fairness and to give mobiles an incentive to do such an adaptation. [less ▲]

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See detailPrédiction numérique des défauts de forme engendrés par l'usinage
Debongnie, Jean-François ULg; Masset, Luc ULg

in Actes du 7ème Congrès de Mécanique. Volume I. Mécanique des Solides (2005, April)

Presentation of a prediction method of form errors arising during machining which has been developed in the manufacturing laboratory of the University of Liège. It combines empirical force models and a ... [more ▼]

Presentation of a prediction method of form errors arising during machining which has been developed in the manufacturing laboratory of the University of Liège. It combines empirical force models and a finite element model of the machined part. A particularly efficient solution scheme has been developed, leading to a valuable tool for the industry. [less ▲]

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See detailA qualitative assessment of the influence of bioturbation in Lake Baikal sediments
Martin, Patrick; Boes, Xavier; Goddeeris, Baudouin et al

in Global and Planetary Change (2005), 46(1-4), 87-99

The impact of bioturbation in Lake Baikal sediments, particularly on rhythmic layering and mixing, was assessed by studying the actual vertical distribution of benthic animals in continuous accumulation ... [more ▼]

The impact of bioturbation in Lake Baikal sediments, particularly on rhythmic layering and mixing, was assessed by studying the actual vertical distribution of benthic animals in continuous accumulation zones selected by seismic survey (Vydrino, Shoulder, Posolskoe Bank, Continent Ridge). To assess the influence of the bioturbation, animals were extracted from short cores and identified at the relevant taxonomic level. The faunal distribution is examined in parallel with the bioturbation tracks observed in thin section. Oligochaeta, Nematoda, Ostracoda, Copepoda, Gammaridae, Chironomidae and Hydrachnidia were found inhabiting the sediment. Among them, only oligochaete worms were assumed to have a significant impact on sediment mixing because of their "conveyor belt" feeding. The other two most abundantly sampled groups, nematods and copepods, belong to the interstitial fauna that has no significant impact on the vertical displacement of sediment particles and do not ingest the sediment. The presence of a benthic fauna as deep as 15 cm in the sediment indicates that the possibility of sediment disturbance by invertebrate activity cannot be dismissed in Lake Baikal. The effect of biological mixing is more limited in the deepest stations because the number of potential bioturbators is reduced, qualitatively as well as quantitatively. Located in the abyssal zone, Continent and Vydrino (but outside turbidites) deep stations appear to be most promising sediment records for tracking climate signal at high resolution. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailEffect of a bovine colostrum supplementation in piglet diet at weaning on growth performances, food ingestion and faecal E. coli concentrations.
Boudry, Christelle ULg; Didderen, Isabelle; Wavreille, José et al

in Proceedings of the British Society of Animal Science (2005, April)

Bovine colostrum supplementation in piglets diet stimulates food intake and reduces the faecal E. coli population during the first week after weaning, inducing a liveweight gain increase. A reduction of ... [more ▼]

Bovine colostrum supplementation in piglets diet stimulates food intake and reduces the faecal E. coli population during the first week after weaning, inducing a liveweight gain increase. A reduction of the food conversion ratio was also observed, suggesting a better nutrient assimilation by the piglets. [less ▲]

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See detailProfile of soluble cytokine receptors in Crohn's disease
Gustot, T.; Lemmers, A.; Louis, Edouard ULg et al

in Gut (2005), 54(4), 488-495

Introduction: Soluble cytokine receptors (sCRs) modulate the in vivo activity of cytokines. Deficient sCR production could participate in the pathogenesis and course of Crohn's disease ( CD). The aim of ... [more ▼]

Introduction: Soluble cytokine receptors (sCRs) modulate the in vivo activity of cytokines. Deficient sCR production could participate in the pathogenesis and course of Crohn's disease ( CD). The aim of the study was to examine the profile of sCRs in CD patients and their modulation by infliximab and corticosteroids. Methods: We prospectively examined active CD patients (aCD) treated with either infliximab (n=21) or corticosteroids (n=9), CD patients in clinical remission (rCD, n=20), ulcerative colitis patients (UC, n=24), and healthy subjects (HS, n=15). Cultures of colonic biopsies were also examined from CD inflamed (n=8), CD non-inflamed (n=7), and healthy mucosa (n=8). Levels of tumour necrosis factor alpha (TNF-alpha), soluble TNF receptor I (sTNFRI), soluble TNF receptor II (sTNFRII), interleukin 1 beta (IL-1 beta), soluble IL-1 receptor I (sIL-1RI), soluble IL-1 receptor II (sIL-1RII), IL-6, soluble IL-6 receptor (sIL-6R), and sgp130 were measured using ELISA. Results: Higher levels of sTNFRI (p<0.05, p<0.01), sTNFRII (p<0.01, p<0.01), sIL-1RI (p<0.05, NS), IL-6 (p<0.01, p<0.01), and sIL-6R (p<0.05, NS) were observed in aCD compared with rCD and HS. Interestingly, sIL-1RII (p<0.05, p<0.01) and sgp130 (p<0.01, p<0.01) were profoundly decreased in aCD compared with rCD and HS, and were negatively correlated with CRP. Deficient production of sIL-1RII was specific to CD ( not observed in ulcerative colitis), and was further confirmed at the mucosal level. Infliximab decreased sTNFRII at one and four weeks (p<0.05) and enhanced sIL-6R levels at one week (p<0.05). Corticosteroids increased sIL-1RII levels at one week (p<0.05). Conclusion: CD is associated with dysregulated production of sCRs. Deficiency in sIL-1RII and sgp130 may be essential to CD pathogenesis. Their replacement through the use of fusion proteins could represent future alternative therapeutic strategies for CD. [less ▲]

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See detailGauche, droite et engagement public
Italiano, Patrick ULg; Deflandre, Dimitri; Jacquemain, Marc ULg

Conference (2005, April)

The paper examines poll survey data to see if the way people invest in public envolvement is different between thos consider themselves to the left and those who consider themselves to the right. It ... [more ▼]

The paper examines poll survey data to see if the way people invest in public envolvement is different between thos consider themselves to the left and those who consider themselves to the right. It appears that the difference beween rightl and left is small and that the main difference is bewteen those who choose a position and those who refuse to choose or do not answer. Rather interestingly, people that see themselves at the center ressembles strongly to non respondants, as if the center was a "refuge value". [less ▲]

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See detailExperimental validation of a diffusion equation-based modeling of the sound field in coupled rooms
Billon, Alexis ULg; Valeau, Vincent; Picaut, Judicaël et al

in Journal of the Acoustical Society of America (2005, April), 117(4), 2581-2581

Sound modeling in coupled rooms (i.e., two acoustically coupled rooms separated by an open area) has attracted considerable attention in the past. However accurate and operational models are still needed ... [more ▼]

Sound modeling in coupled rooms (i.e., two acoustically coupled rooms separated by an open area) has attracted considerable attention in the past. However accurate and operational models are still needed, principally when three or more rooms are coupled. In recent papers, a diffusion equation-based model has been applied to unusual room shapes. For the coupled rooms geometry, this diffusion model has been validated successfully by comparison with the classical statistical theory in a parametrical study of the coupling parameters [Billon et al., J. Acoust. Soc. Am. 116, 2553 (2004)]. In the present work, the diffusion model results are validated by means of a comparison with experimental results, both in terms of sound attenuation and reverberation time. A comparison is also provided with results given by the statistical theory and a ray tracing program. For this purpose, experiments have been conducted in two coupled classrooms with two different sound source locations. The results show a very good agreement between the diffusion model and the experiments. Conversely, the statistical model is not valid for modeling accurately the sound field distribution and decay in both coupled rooms. At last, the diffusion model runs much faster than the ray tracing program. [less ▲]

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See detailMallarmé : retour du même, presque autre
Durand, Pascal ULg

in Critique (2005), 695

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See detailInfluence de la température du fluide de soufflage sur le bruit de fente
Glesser, Martin; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2005, April)

Les bouches de soufflage des systèmes de ventilation peuvent produire des sifflements de forte intensité. Pour étudier leur mécanisme de production un modèle expérimental où un jet rectangulaire heurte ... [more ▼]

Les bouches de soufflage des systèmes de ventilation peuvent produire des sifflements de forte intensité. Pour étudier leur mécanisme de production un modèle expérimental où un jet rectangulaire heurte une plaque fendue est étudié. Cette configuration donne naissance à un type de sons auto-entretenus connus sous le nom de bruit de fente. [less ▲]

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See detailAcidic extracellular pH induces matrix metalloproteinase-9 expression in mouse metastatic melanoma cells through the phospholipase D-mitogen-activated protein kinase signaling
Kato, Y.; Lambert, Charles ULg; Colige, Alain ULg et al

in Journal of Biological Chemistry (2005), 280(12), 10938-10944

The extracellular pH (pHe) of tumor tissues is often acidic, which can induce the expression of several proteins. We previously showed that production of matrix metalloproteinase-9 (MMP-9) was induced by ... [more ▼]

The extracellular pH (pHe) of tumor tissues is often acidic, which can induce the expression of several proteins. We previously showed that production of matrix metalloproteinase-9 (MMP-9) was induced by culturing cells at acidic pHe (5.4-6.5). Here we have investigated the signal transduction pathway by which acidic pHe induces MMP-9 expression. We found that acidic pHe (5.9) activated phospholipase D (PLD), and inhibition of PLD activity by 1-butanol and Myr-ARF6 suppressed the acidic pHe-induced MMP-9 expression. Exogenous PLD, but not phosphatidylinositol-specific PLC or PLA(2), mimicked MMP-9 induction by acidic pHe. Western blot analysis revealed that acidic pHe increased the steady-state levels of phosphorylated extracellular signal-regulated kinases 1/2 and p38 and that the PLD inhibitors suppressed these increases. Using 5'-deletion mutant constructs of the MMP-9 promoter, we found that the acidic pHe-responsive region was located at nucleotide -670 to -531, a region containing the NF kappa B binding site. A mutation into the NF kappa B binding site reduced, but not completely, the acidic pHe- induced MMP-9 promoter activity, pand NF kappa B activity was induced by acidic pHe. Pharmacological inhibitors specific for mitogen-activated protein kinase kinase 1/2 (PD098059) and p38 (SB203580) attenuated the acidic pHe- induced NF kappa B activity and MMP-9 expression. These data suggest that PLD, mitogen-activated protein kinases (extracellular signal-regulated kinases 1/2 and p38), and NF kappa B mediate the acidic pHe signaling to induce MMP-9 expression. A transcription factor(s) other than NF kappa B may also be involved in the MMP-9 expression. [less ▲]

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