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See detailLarge-pore membrane hemofiltration increases cytokine clearance and improves right ventricular-vascular coupling during endotoxic shock in pigs
Lambermont, Bernard ULg; Delanaye, Pierre ULg; Dogné, Jean-Michel ULg et al

in Artificial Organs (2006), 30(7), 560-564

Hemodynamic improvement in patients suffering from both septic shock and renal failure who received hemofiltration suggested that an extrarenal epuration technique could be of interest in patients with ... [more ▼]

Hemodynamic improvement in patients suffering from both septic shock and renal failure who received hemofiltration suggested that an extrarenal epuration technique could be of interest in patients with septic shock alone. However, most of the studies using continuous venovenous hemofiltration (CVVH) in this setting evidenced neither cytokine clearance nor significant reduction in their plasma level. Lack of significant clearance was explained in part by the small size of the membrane pores. Therefore, we investigated the effects of large-pore membrane hemofiltration (LPHF) during endotoxic shock in pigs on interleukin 6 (IL-6) and interleukin 10 (IL-10) clearances, and on right ventricular (RV)-vascular coupling. Thirteen anesthetized healthy pigs weighing 20-30 kg were divided into two groups. In the Endo group (n = 6), the pigs received a 0.5-mg/kg endotoxin infusion over a period of 30 mins from T0 to T30. In the EndoHF group (n = 7), LPHF (cutoff = 80 kDa) and an ultrafiltration rate of 45 mL/kg/h were started 30 mins after the end of the endotoxin infusion, from T60 to T240. In this model of porcine endotoxic shock, LPHF was responsible for a significant clearance of IL-6 (20 mL/min) and Il-10 (14 mL/min), and for an improvement in RV-vascular coupling. [less ▲]

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See detailLarge-scale alignments of quasar polarisations: a detailed study of the spinless-particle scenario
Payez, Alexandre ULg

Doctoral thesis (2013)

The main motivation for our work has been a puzzling observation concerning quasars. No one expected the existence of correlations in the polarisation of visible light coming from objects separated by ... [more ▼]

The main motivation for our work has been a puzzling observation concerning quasars. No one expected the existence of correlations in the polarisation of visible light coming from objects separated by gigaparsecs, until they were first reported in the form of a redshift-dependent effect that has become more and more significant with the growth of the data sample. In close connexion with the observational group, we have studied in detail the most widely considered scenario, involving axion-photon mixing in extragalactic magnetic fields. After a systematic investigation, we conclude that it is very unlikely that these observations can be accounted for by axion-like particles, given current data and constraints. We also derive new limits on the parameters describing these particles. This thesis gives in particular a detailed account of the consequences of axion-photon mixing on polarisation, studies the influence of averages over the frequency (including a wave-packet treatment of the mixing), and discusses the consequences of different magnetic-field morphologies. [less ▲]

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See detailLarge-scale alignments of quasar polarization vectors. Observational evidence and possible implications for cosmology and fundamental physics
Hutsemekers, Damien ULg

Scientific conference (2014, March 05)

Based on a sample of 355 quasars with significant optical linear polarization and using various statistical methods, we show that quasar polarization vectors are not randomly oriented over the sky with a ... [more ▼]

Based on a sample of 355 quasars with significant optical linear polarization and using various statistical methods, we show that quasar polarization vectors are not randomly oriented over the sky with a probability often in excess of 99.9%. The polarization vectors appear coherently aligned over huge regions of the sky (~1 Gpc), located at both low (z ~0.5) and high (z ~1.5) redshifts and characterized by different preferred directions of the polarization. These characteristics make the alignment effect difficult to explain in terms of contamination by instrumental or interstellar polarization in our Galaxy. We notice that the region of the sky where the alignments are prominent is not far from preferred directions tentatively identified in the Cosmic Microwave Background. Polarization alignments may thus reveal structures at scales beyond the homogeneity scale of concordance cosmology. Several interpretations are discussed. In particular, we show that the dichroism and birefringence predicted by photon pseudo-scalar oscillation along the line of sight cannot reproduce the observed properties of the alignments. Besides, accurate measurements of quasar circular polarization allow us to strongly constrain the parameter space of axion-like particles. [less ▲]

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See detailLarge-Scale Alignments of Quasar Polarization Vectors: Evidence at Cosmological Scales for Very Light Pseudoscalar Particles Mixing with Photons ?
Hutsemekers, Damien ULg; Payez, Alexandre ULg; Cabanac, R et al

in Bastien, Pierre (Ed.) Astronomical Polarimetry 2008: Science from Small to Large Telescopes. ASPC 449 (2011, November 01)

Based on a sample of 355 quasars with significant optical polarization, we found that quasar polarization vectors are not randomly oriented over the sky as naturally expected. The probability that the ... [more ▼]

Based on a sample of 355 quasars with significant optical polarization, we found that quasar polarization vectors are not randomly oriented over the sky as naturally expected. The probability that the observed distribution of polarization angles is due to chance is lower than 0.1%. The polarization vectors of the light from quasars are aligned although the sources span huge regions of the sky (˜ 1 Gpc). Groups of quasars located along similar lines of sight but at different redshifts (typically z ≍ 0.5 and z ≍ 1.5) are characterized by different preferred directions of polarization. These characteristics make the observed alignment effect difficult to explain in terms of a local contamination by interstellar polarization in our Galaxy. Interpreted in terms of a cosmological-size effect, we show that the dichroism and birefringence predicted by a mixing between photons and very light pseudoscalar particles within a magnetic field can qualitatively reproduce the observations. We find that circular polarization measurements could help constrain this mechanism. [less ▲]

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See detailLarge-scale Analysis of the human genome: from DNA sequence analysis to the modeling of replication in higher eukaryotes
Arneodo, Alain; d'Aubenton-Carafa, Y.; Audit, B. et al

in Proceeding of the 14th EUSIPCO (2006)

We explore large-scale nucleotide compositional fluctuations along the human genome through the optics of the wavelet transform mi- croscope. Analysis of the TA and GC skews reveals the existence of ... [more ▼]

We explore large-scale nucleotide compositional fluctuations along the human genome through the optics of the wavelet transform mi- croscope. Analysis of the TA and GC skews reveals the existence of strand asymmetries associated to transcription and/or replication The investigation of 14854 intron-containing genes shows that both skews display a characteristic step-like profile exhibiting sharp tran- sitions between transcribed (finite bias) and non-transcribed (zero bias) regions. As we observe for 7 out of 9 origins of replica- tion experimentally identified so far, the (AT+GC) skew exhibits rather sharp upward jumps, with a linear decreasing profile in be- tween two successive jumps. We describe a multi-scale method- ology that allows us to predict 1012 replication origins in the 22 human autosomal chromosomes. We present a model of replica- tion with well-positioned replication origins and random termina- tion sites that accounts for the observed characteristic serrated skew profiles. We emphasize these putative replication initiation zones as regions where the chromatin fiber is likely to be more open so that DNA be easily accessible. In the crowded environment of the cell nucleus, these intrinsic decondensed structural defects actually predisposes the fiber to spontaneously form rosette-like structures that provide an attractive description of genome organization into replication foci that are observed in interphase mammalian nuclei. [less ▲]

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See detailLarge-Scale Clinical Expansion of Mesenchymal Stem Cells in the GMP-Compliant, Closed Automated Quantum® Cell Expansion System: Comparison with Expansion in Traditional T-Flasks
LECHANTEUR, Chantal ULg; Baila, Stefano; Janssen, Michel Etienne et al

in Journal of Stem Cell Research & Therapy (2014), 4(8),

Objectives: Significant advances have been achieved regarding the knowledge of the immunoregulatory properties of mesenchymal stem cells (MSC). We are currently involved in several clinical protocols ... [more ▼]

Objectives: Significant advances have been achieved regarding the knowledge of the immunoregulatory properties of mesenchymal stem cells (MSC). We are currently involved in several clinical protocols evaluating these properties in different settings including hematopoietic cells or solid organ transplantation, and severe or refractory autoimmune disorders. Considering the large number of ex-vivo expanded cells required for these clinical protocols (MSC dose varies from 1 to 4x10-6 MSC/kg patient per infusion), we evaluated the Quantum® device, a GMPcompliant, functionally closed, automated hollow fiber bioreactor system and compared it with our traditional clinical culture system in flasks. Methods: Primary and pre-enriched MSC expansions were simultaneously conducted in both culture systems and evaluated in terms of expansion rates and compliance with quality specifications and ISCT-release criteria. Due to practical considerations, most of the experiments conducted in the bioreactor (P1 and P2 expansions) used thawed MSC. These were compared with both fresh and thawed MSC expansions in flasks. Results: The Quantum® device reproducibly produced therapeutic MSC doses that fulfill ISCT-release criteria, are sterile, devoid of mycoplasma and endotoxin, have normal karyotypes and demonstrate immunosuppressive and differentiation capacities in vitro. Cells also grew faster in the bioreactor than in flasks during passage P1 (doubling time 40 compared to 56 hours in flasks) and P2 expansions but not during the primary expansion phase (P0). Seeding 20x10-6 thawed P2-preselected cells on the device allowed us to harvest 110-276x10-6 MSC after a 7 day expansion; seeding 50x10-6 cells resulted in 291-334x10-6 MSC harvested. Conclusion: In conclusion, the Quantum® device is an excellent system to produce a clinical dose of MSC but cost-effectiveness varies as a function of the manufacturing strategy in place. For our particular situation, the use of the Quantum device didn't result in a cost saving solution. [less ▲]

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See detailLarge-scale coherent orientations of quasar polarisation vectors: interpretation in terms of axion-like particles
Payez, Alexandre ULg; Hutsemekers, Damien ULg; Cudell, Jean-René ULg

in AIP Conference Proceedings (2010), 1274,

The observation of redshift-dependent coherent orientations of quasar polarisation vectors over cosmological distances in some regions of the sky is reviewed. Based on a good-quality sample of 355 ... [more ▼]

The observation of redshift-dependent coherent orientations of quasar polarisation vectors over cosmological distances in some regions of the sky is reviewed. Based on a good-quality sample of 355 measured quasars, this observation seems to infer the existence of a new effect acting on light propagation on such huge distances. A solution in terms of nearly massless axion-like particles has been proposed in the literature and its current status is discussed. [less ▲]

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See detailLarge-scale eradication of rabies using recombinant vaccinia-rabies vaccine
Brochier, Bernard; Kieny, M. P.; Costy, F. et al

in Nature (1991), 354(19/26 December), 520-521

Detailed reference viewed: 31 (4 ULg)
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See detailLarge-scale fire test of unprotected cellular beam acting in membrane action
Vassart, Olivier; Bailey, C.G.; Hawes, M. et al

in Proceedings of the Institution of Civil Engineers: Structures and Buildings (2012), 165(7), 327334

This paper describes a full scale fire test performed recently on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part ... [more ▼]

This paper describes a full scale fire test performed recently on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. The natural fire was created by a wood crib fire load of 700 MJ/m² and the 9 x 15 m floor survived the fire that peaked at 1000°C and lasted for about 90 minutes. Blind predictions of the air temperature development by the software OZone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described. [less ▲]

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See detailLarge-Scale Fire Test of Unprotected Cellular Beam Acting in Membrane Action
Vassart, Olivier; Bailey, C. G.; Hawes, M. et al

in Journal of Structural Fire Engineering (2011), 2(4), 259-268

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in ... [more ▼]

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. The natural fire was created by a wood crib fire load of 700 MJ/m2 and the 9 × 15 m floor survived the fire that peaked at 1000°C and lasted for 90 minutes. Blind predictions of the air temperature development by the software OZone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described. [less ▲]

Detailed reference viewed: 78 (32 ULg)
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See detailLarge-scale fire test of unprotected cellular beam acting in membrane action
Vassart, Olivier; Bailey, C. G.; Hawes, M. et al

in Franssen, Jean-Marc; Kodur, Venkatesh (Eds.) Proceedings of the Sixth International Conference Structures in Fire (2010, June)

This paper describes a full scale fire test performed recently on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part ... [more ▼]

This paper describes a full scale fire test performed recently on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. The natural fire was created by a wood crib fire load of 700 MJ/m² and the 9 x 15 m floor survived the fire that peaked at 1000°C and lasted for 90 minutes. Blind predictions of the air temperature development by the software Ozone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described. [less ▲]

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See detailLarge-scale flow and transport modelling for the management of groundwater bodies: the Geer case-study
Orban, Philippe ULg; Goderniaux, Pascal ULg; Brouyère, Serge ULg

in AquaTerra Final Conference. Programme & Proceedings (2009, March)

Detailed reference viewed: 34 (3 ULg)
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See detailLarge-scale groundwater flow and transport modeling: Methodology and application to the Meuse Basin – Belgium
Orban, Philippe ULg; Brouyère, Serge ULg; Corbeanu, Horatiu et al

in Bringing Groundwater Quality Research to the Watershed Scale - Proceedings of GQ2004 (2005)

To meet the requirements of the EU Water Framework Directive, an integrated water management project named PIRENE was initiated by the Walloon Region of Belgium. A partner of this project, the ... [more ▼]

To meet the requirements of the EU Water Framework Directive, an integrated water management project named PIRENE was initiated by the Walloon Region of Belgium. A partner of this project, the Hydrogeology Group of the University of Liège, is in charge of the development of a physically based transient groundwater flow and transport model for the Walloon part of the Meuse Basin (approximately 17 000 km2). To face the problems associated with this large-scale model, a general approach has been developed that combines a hydrogeological database and GIS systems to manage data. Techniques of spatial discretization have been applied that optimize the number of unknowns. For modelling groundwater flow and transport on a large scale, a new numerical approach called the Hybrid Finite Element Mixing Cell (HFEMC) has been implemented in the 3-D simulator SUFT3D. [less ▲]

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See detailLarge-scale groundwater flow and transport modelling : Methodology and application to the Geer basin, Belgium
Orban, Philippe ULg; Dassargues, Alain ULg; Brouyère, Serge ULg

in Stauffer, Fr.; Dassargues, Alain (Eds.) Quantitative Geology from Multiple Sources: S10 Use of multiple sources in conditioning/calibrating groundwater flow and transport models (2006)

Efficient and sustainable management of water resources should be considered from an integrated way, at the basin scale. For that purpose, physically-based, spatially distributed modelling tools has ... [more ▼]

Efficient and sustainable management of water resources should be considered from an integrated way, at the basin scale. For that purpose, physically-based, spatially distributed modelling tools has turned to be very useful. If regional groundwater flow model have been developed for years now, large scale contaminant transport models are still almost inexistent. The objective of this extended abstract is to present briefly new concepts for large transport modelling, more particularly a modelling approach, the Hybrid Finite Element Mixing Cell (HFEMC) developed by the Hydrogeology Group of the University of Liège and implemented in the 3D simulator SUFT3D. First steps for the application to the Geer basin are also presented. [less ▲]

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See detailLarge-scale groundwater modelling in the Walloon part of the Meuse basin: challenges and first steps
Brouyère, Serge ULg; Orban, Philippe ULg

Conference (2006, December 14)

This presentation described the first steps in the development of large (groundwater body) scale groundwater flow and transport modelling in the Meuse district

Detailed reference viewed: 7 (0 ULg)
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See detailLarge-scale identification of selenium metabolites by online size-exclusion-reversed phase liquid chromatography with combined inductively coupled plasma (ICP-MS) and electrospray ionization linear trap-Orbitrap mass spectrometry (ESI-MS(n))
Preudhomme, Hugues; Far, Johann ULg; Gil-Casal, Sandra et al

in Metallomics (2012), 4(5), 422-432

A method was developed for the comprehensive cartography of the selenium metabolites synthesized in the process of conversion of selenite [Se(IV)] into organic compounds and enrichment of yeast with ... [more ▼]

A method was developed for the comprehensive cartography of the selenium metabolites synthesized in the process of conversion of selenite [Se(IV)] into organic compounds and enrichment of yeast with selenium. The number of compounds detected was considerably increased (49) owing to the optimization of the fractionation procedure and the use of UPLC. The increased purity of the minor selenoorganic amino acids and oligopeptides allowed successful on-line de-novo identification based on the exact mass (o1 ppm) and fragmentation (MS2/MS3) mass spectra obtained with high resolution and high mass accuracy. The quality of mass spectra allowed the re-interpretation of previously reported structures of some selenium species. [less ▲]

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See detailLarge-scale modelling within the PIRENE programme in the Walloon Region of Belgium
Dassargues, Alain ULg

Scientific conference (2003, September 29)

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See detailA large-scale multicentre study of patient skin doses in interventional cardiology: dose-area product action levels and dose reference levels.
Bogaert, E.; Bacher, K.; Lemmens, K. et al

in The British journal of radiology (2009), 82(976), 303-12

For 318 patients in 8 different Belgian hospitals, the entire skin-dose distribution was mapped using a grid of 70 thermoluminescence dosimeters per patient, allowing an accurate determination of the ... [more ▼]

For 318 patients in 8 different Belgian hospitals, the entire skin-dose distribution was mapped using a grid of 70 thermoluminescence dosimeters per patient, allowing an accurate determination of the maximum skin dose (MSD). Dose-area product (DAP) values, exposure parameters and geometry, together with procedure, patient and cardiologist characteristics, were also registered. Procedures were divided into two groups: diagnostic procedures (coronary angiography) and therapeutic procedures (dilatation, stent, combined procedures (e.g. coronary angiography + dilatation + stent)). The mean value of the MSD was 0.310 Gy for diagnostic and 0.699 Gy for therapeutic procedures. The most critical projection for receiving the MSD is the LAO90 (left anterior oblique) geometry. In 3% of cases, the MSD exceeded the 2 Gy dose threshold for deterministic effects. Action levels in terms of DAP values as the basis for a strategy for follow-up of patients for deterministic radiation skin effects were derived from measured MSD and cumulative DAP values. Two DAP action levels are proposed. A first DAP action level of 125 Gy cm(2) corresponding to the dose threshold of 2 Gy would imply an optional radiopathological follow-up depending on the cardiologist's decision. A second DAP action level of 250 Gy cm(2) corresponding to the 3 Gy skin dose would imply a systematic follow-up. Dose reference levels - 71.3 Gy cm(2) for diagnostic and 106.0 Gy cm(2) for therapeutic procedures - were derived from the 75 percentile of the DAP distributions. As a conclusion, we propose that total DAP is registered in patient's record file, as it can serve to improve the follow-up of patients for radiation-induced skin injuries. [less ▲]

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