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See detailQuantitative study of catalytic activity and catalytic deactivation of Fe–Co/Al2O3 catalysts for multi-walled carbon nanotube synthesis by the CCVD process
Pirard, Sophie ULg; Heyen, Georges ULg; Pirard, Jean-Paul ULg

in Applied Catalysis A : General (2010), 382

The catalytic deactivation during multi-walled carbon nanotube (MWNT) synthesis by the CCVD process and the influence of hydrogen on it were quantified. Initial specific reaction rate, relative specific ... [more ▼]

The catalytic deactivation during multi-walled carbon nanotube (MWNT) synthesis by the CCVD process and the influence of hydrogen on it were quantified. Initial specific reaction rate, relative specific productivity and catalytic deactivation were studied. Carbon source was ethylene, and a bimetallic iron–cobalt catalyst supported on alumina was used. The catalytic deactivation was modeled by a decreasing hyperbolic law, reflecting the progressive accumulation of amorphous carbon on active sites. While the initial specific reaction rate was found not to be influenced by hydrogen, catalytic deactivation was found to be modified in the presence of hydrogen, which delayed and slowed down the deactivation by avoiding amorphous carbon deposition, thus leading to a greater relative specific productivity of carbon nanotubes. [less ▲]

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See detailA quantitative study of O stars in NGC 2244 and the Monoceros OB2 association
Martins, F.; Mahy, Laurent ULg; Hillier, D. J. et al

in Astronomy and Astrophysics (2012), 538

<BR /> Aims: Our goal is to determine the stellar and wind properties of seven O stars in the cluster NGC 2244 and three O stars in the OB association Mon OB2. These properties give us insight into the ... [more ▼]

<BR /> Aims: Our goal is to determine the stellar and wind properties of seven O stars in the cluster NGC 2244 and three O stars in the OB association Mon OB2. These properties give us insight into the mass loss rates of O stars. They allow us to both check the validity of rotational mixing in massive stars and to better understand the effects of the ionizing flux and wind mechanical energy release on the surrounding interstellar medium and its influence on triggered star formation. <BR /> Methods: We collected optical and UV spectra of the target stars that we analyzed by means of atmosphere models computed with the code CMFGEN. The spectra of binary stars were disentangled and the components studied separately. <BR /> Results: All stars have an evolutionary age less than 5 million years, with the most massive stars being among the youngest. Nitrogen surface abundances show no clear relation with projected rotational velocities. Binaries and single stars show the same range of enrichment. This is attributed to the youth and/or wide separation of the binary systems in which the components have not (yet) experienced strong interaction. A clear trend toward greater enrichment in higher luminosity objects is observed, consistent with what evolutionary models with rotation predict for a population of O stars at any given age. We confirm the weakness of winds in late O dwarfs. In general, mass loss rates derived from UV lines are lower than mass loss rates obtained from Hα. The UV mass loss rates are even lower than the single-line driving limit in the latest type dwarfs. These issues are discussed in the context of the structure of massive stars winds. The evolutionary and spectroscopic masses are in agreement above 25 M[SUB]&sun;[/SUB], but the uncertainties are large. Below this threshold, the few late-type O stars studied here indicate that the mass discrepancy still seems to hold. Appendix A is available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A> [less ▲]

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See detailA quantitative study of peripheral blood stem cell contamination in diffuse large-cell non-Hodgkin's lymphoma: one-half of patients significantly mobilize malignant cells.
Jacquy, C.; Soree, A.; Lambert, Frédéric ULg et al

in British Journal of Haematology (2000), 110(3), 631-7

Autologous transplantation using peripheral blood stem cells (PBSCs) collected after chemotherapy, followed by growth factor administration (ASCT), is increasingly used in the treatment of non-Hodgkin's ... [more ▼]

Autologous transplantation using peripheral blood stem cells (PBSCs) collected after chemotherapy, followed by growth factor administration (ASCT), is increasingly used in the treatment of non-Hodgkin's lymphoma (NHL). However, quantitative data regarding contaminating malignant cells in the harvests are still scarce. We prospectively investigated 37 diffuse large-cell lymphomas (DLCLs) in complete remission (CR) that were treated according to multicentric protocols at our centre. DNA was extracted from the diagnostic lymph node. The complementarity-determining region (CDR) III was sequenced and a patient-specific oligomer synthesized. Contamination was evaluated semiquantitatively by polymerase chain reaction (PCR) and was confirmed by a limiting dilution analysis. PBSCs collected at regeneration after administration of granulocyte colony-stimulating factor (G-CSF), steady-state bone marrow (BM) and peripheral blood samples at CR were compared. DNA was available in 37 patients, from which 22 rearrangements could be sequenced. Patients (n = 15) who had both the required follow-up samples and a suitable clonal marker were investigated. In two cases, the patient-specific PCR assay set up at diagnosis later gave false-negative results in samples in which clonal DNA was still detectable by other sets of primers. PBSC contamination was highly variable: 7 out of 15 patients showed a PBSC/BM ratio of NHL cells greater than 1 log, whereas 8 out of 15 patients showed no difference and could vary from one apheresis to another. Eight ASCTs were performed, five of which used highly contaminated PBSCs: four patients relapsed early, three with disseminated lymphoma. Thus, 50% of DLCLs in CR seem to mobilize significantly malignant cells at regeneration under G-CSF. Considering the higher numbers of cells reinfused, this translates into a much higher number of lymphoma cells reinfused when compared with autologous bone marrow transplantation (ABMT). However, their clonogenic potential remains unknown and, despite concerning observations in certain cases, it is still unclear whether this has an impact upon the outcome of ASCT. [less ▲]

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See detailA quantitative study of the O stars in NGC 2244
Mahy, Laurent ULg; Martins, F.; Hillier, D. J. et al

in Journal of Physics: Conference Series (2011)

Abstract. NGC2244 located in the Rosette Nebula is a young open cluster composed of seven O-type stars. A first paper focused on the multiplicity of these stars, revealed only one binary system out of the ... [more ▼]

Abstract. NGC2244 located in the Rosette Nebula is a young open cluster composed of seven O-type stars. A first paper focused on the multiplicity of these stars, revealed only one binary system out of the seven studied stars. The minimum binary fraction of this cluster (~ 14%) diff ers to the average fraction measured on the nearby clusters (~ 44%). In order to better constrain this discrepancy, an analysis based on the determination of the stellar and wind parameters of these stars with the CMFGEN atmosphere code was performed. The main results con rfim that all the stars have an age between 0 and 5 Myr, and that the N surface abundance appears to be consistent with the evolutionary models for a population of stars of the same age. Moreover, this investigation exhibits the existence of dynamical interactions inside this young open cluster sufficiently strong to eject the hottest component from its centre. [less ▲]

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See detailQuantitative temperature monitoring of a heat tracing experiment using cross-borehole ERT
Hermans, Thomas ULg; Wildemeersch, Samuel ULg; Jamin, Pierre ULg et al

in Geothermics (2015), 53

The growing demand for renewable energy leads to an increase in the development of geothermal energy projects and heat has become a common tracer in hydrology and hydrogeology. Designing geothermal ... [more ▼]

The growing demand for renewable energy leads to an increase in the development of geothermal energy projects and heat has become a common tracer in hydrology and hydrogeology. Designing geothermal systems requires a multidisciplinary approach including geological and hydrogeological aspects. In this context, electrical resistivity tomography (ERT) can bring relevant, qualitative and quantitative information on the temperature distribution in operating shallow geothermal systems or during heat tracing experiments. We followed a heat tracing experiment in an alluvial aquifer using cross-borehole time-lapse ERT. Heated water was injected in a well while water of the aquifer was extracted at another well. An ERT section was set up across the main flow direction. The results of ERT were transformed into temperature using calibrated petrophysical relationships. These ERT-derived temperatures were then compared to direct temperature measurements in control piezometers collected with distributed temperature sensing (DTS) and groundwater temperature loggers. Spatially, it enabled to map the horizontal and vertical extent of the heated water plume, as well as the zones where maximum temperatures occurred. Quantitatively, the temperatures and breakthrough curves estimated from ERT were in good agreement with the ones observed directly during the rise and maximum of the curve. An overestimation, likely related to 3D effects, was observed for the tail of the heat breakthrough curve. The error made on temperature can be estimated to be between 10 to 20 %, which is a fair value for indirect measurements. From our data, we estimated a quantification threshold for temperature variation of 1.2°C. These results suggest that ERT should be considered when designing heat tracing experiments or geothermal systems. It could help also to assess the geometrical complexity of the concerned reservoirs. It also appears that ERT could be a useful tool to monitor and control geothermal systems once they are in operation. [less ▲]

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See detailQuantitative turbidimetric assay for determining myoglobin evaluated.
Delanghe, J.; Chapelle, Jean-Paul ULg; el Allaf, M. et al

in Annals of Clinical Biochemistry (1991), 28 ( Pt 5)

A recently introduced turbidimetric immunoassay using shell/core particles for determination of myoglobin (Turbiquant Myoglobin, Behringwerke, Marburg, Germany) was evaluated on the Behring Turbitimer ... [more ▼]

A recently introduced turbidimetric immunoassay using shell/core particles for determination of myoglobin (Turbiquant Myoglobin, Behringwerke, Marburg, Germany) was evaluated on the Behring Turbitimer analyzer. Intra-assay CV varied between 1.0% and 3.2%; interassay CV was between 2.0% and 3.6%. Linear results were obtained between 2.8 nmol/L and 36.7 nmol/L. Manual dilution in saline solution allowed measurement of myoglobin concentrations up to 25,400 nmol/L. In the tested range, no high-dose 'hook' effect was observed. Haemolysis interfered with the assay when haemoglobin concentrations exceeded 2 g/L. The occurrence of error codes due to the presence of triglycerides was shown to depend on particle size. Repeat assays on diluted samples were necessary at triglyceride concentrations of 2.3 mmol/L for post-prandial chylomicrons (200-1000 nm), and at 11-31 mmol/L for very-low density lipoprotein-triglycerides (80-200 nm). No significant interferences of haptoglobin, bilirubin, iodine containing contrast media, and rheumatoid factors were detected for the assay. Treatment of lipaemic samples with Lipoclean (Behringwerke) resulted in lower myoglobin values. Simultaneously drawn serum and heparin-plasma samples gave comparable myoglobin results. However, values obtained in EDTA- or citrate-treated plasma samples occasionally differed significantly from serum values. The upper reference limit for myoglobin concentration was 4.2 nmol/L. The turbidimetric assay correlated well with a radioimmunoassay (Byk-Sangtec; r = 0.892) and with the automated nephelometric assay (Behringwerke; r = 0.944). Values obtained by turbidimetry were comparable to those obtained by the latex agglutination test (Behringwerke). [less ▲]

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See detailQuantitative ultrasonography for the noninvasive assessment of equine bone: a review
Carstanjen, B.; Gabriel, Annick ULg

in IPPOLOGIA (2006), 17(4), 11-15

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See detailQuantitative ultrasound and dual-X-ray absorptiometry-measurements of the third metacarpal bone in horses
Carstanjen, B; Duboeuf, F; Detilleux, Johann ULg et al

in Journal of Bone and Mineral Research (2000), 15

The purpose of the study was to examine the relationship between in vivo and ex vivo quantitative ultrasound (QUS) measurements with and without soft tissue and ex vivo dual X-ray absorptiometry (DXA) at ... [more ▼]

The purpose of the study was to examine the relationship between in vivo and ex vivo quantitative ultrasound (QUS) measurements with and without soft tissue and ex vivo dual X-ray absorptiometry (DXA) at different aspects and levels of the third metacarpal bone (MC III) in horses. Both MC III of 8 clinically normal horses were divided in 9 sites (lateral, medial, dorsal aspect; proximal, mid, distal level). Speed of sound (SOS) measurements were performed with a QUS multisite device (Sunlight Ltd., Rehovot, Israel) and a DXA device (Hologic Inc., Bedford, USA) was used to evaluate cortical bone mineral density (BMD) at each site. Ex vivo data on MC III were analysed with a mixed model to test the hypothesis of no difference between aspect and level in QUS and DXA while adjusting for fixed member and for random horse effects. Pearson correlation coefficients between SOS and BMD obtained on MC III with soft tissue were calculated for each member and site. A mixed model was used to determine whether there is a difference between in vivo and ex vivo SOS data while adjusting for fixed aspect, level, and member and random horse effects. Highly significant (p<0.001) differences were obtained between aspects for ex vivo SOS and DXA measurements. Differences (p<0.001) were obtained between measurement levels for DXA data. The table shows least squares means (LSM) and standard errors (Std Err) for QUS and DXA measurements performed at different aspects. The correlation coefficient between SOS and DXA over all 9 sites and both MC III was negative (r=-0.28; p<0.001). In vivo and ex vivo SOS data were different (p<0.01) BUT NOT EX VIVO DATA WITH AND WITHOUT SOFT TISSUE (P>0.05). The study suggests that, in horses, SOS results can not be explained only by BMD, but could reflect additional properties of bone, such as elasticity, architecture or bone strength. Our results indicate that soft tissue does not influence ex vivo SOS measurement results. [less ▲]

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See detailQuantitative ultrasound techniques for the assessment of osteoporosis : Expert agreement on current status
Glüer, CC; Reginster, Jean-Yves ULg

in Journal of Bone and Mineral Research (1997), 12(8), 1280-1288

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See detailQuantitative X-ray microanalysis of precipitates in zinc-aluminium-copper
Rashev, P.; Terziev, Luben; Lecomte-Beckers, Jacqueline ULg et al

in Proceeding of the 12th International Congress on XR optics and microanalyses (1989)

The aim of the present study is to adapt the Cliff-Lorimer method for quantitative analysis of thin foils and to obtain information about the composition of fine metastable precipitates in Zn-Al-Cu alloys ... [more ▼]

The aim of the present study is to adapt the Cliff-Lorimer method for quantitative analysis of thin foils and to obtain information about the composition of fine metastable precipitates in Zn-Al-Cu alloys. The coefficients K(al-zn) and K(al-cu) were determined for accelerating voltage of 200 kV, about which there has no been data ever mentioned. Some applications of the method are given. [less ▲]

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See detailQuantitative, structural, and image-based mechanical analysis of nonunion fracture repaired by genetically engineered mesenchymal stem cells
Kallai, Ilan; van Lenthe, G. Harry; Ruffoni, Davide ULg et al

in JOURNAL OF BIOMECHANICS (2010), 43(12), 2315-2320

Stem cell-mediated gene therapy for fracture repair, utilizes genetically engineered mesenchymal stem cells (MSCs) for the induction of bone growth and is considered a promising approach in skeletal ... [more ▼]

Stem cell-mediated gene therapy for fracture repair, utilizes genetically engineered mesenchymal stem cells (MSCs) for the induction of bone growth and is considered a promising approach in skeletal tissue regeneration. Previous studies have shown that murine nonunion fractures can be repaired by implanting MSCs over-expressing recombinant human bone morphogenetic protein-2 (rhBMP-2). Nanoindentation studies of bone tissue induced by MSCs in a radius fracture site indicated similar elastic modulus compared to intact murine bone, eight weeks post-treatment. In the present study we sought to investigate temporal changes in microarchitecture and biomechanical properties of repaired murine radius bones, following the implantation of MSCs. High-resolution micro-computed tomography (micro-CT) was performed 10 and 35 weeks post MSC implantation, followed by micro-finite element (micro-FE) analysis. The results have shown that the regenerated bone tissue remodels over time, as indicated by a significant decrease in bone volume, total volume, and connectivity density combined with an increase in mineral density. In addition, the axial stiffness of limbs repaired with MSCs was 2-1.5 times higher compared to the contralateral intact limbs, at 10 and 35 weeks post-treatment. These results could be attributed to the fusion that occurred in between the ulna and radius bones. In conclusion, although MSCs induce bone formation, which exceeds the fracture site, significant remodeling of the repair callus occurs over time. In addition, limbs treated with an MSC graft demonstrated superior biomechanical properties, which could indicate the clinical benefit of future MSC application in nonunion fracture repair. (C) 2010 Elsevier Ltd. All rights reserved. [less ▲]

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See detailQuantités de matières transportées en suspension et en solution par l'effluent majeur des karsts belges: la Meuse
Close-Lecocq, Jean-François; Ek, Camille ULg

in Annales de la Société Géologique de Belgique (1985)

In the Meuse River at Liège, for a drainage basin of 16 400 sq km,the average annual suspended load is 388 000 tons and the load in dissolution 1 092 000 tons.

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See detailLes quantités physiques mesurées par les récepteurs GPS
Warnant, René ULg

Conference given outside the academic context (1995)

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See detailQuantization of pore corrugation in SBA-15 by image analysis of electron tomograms
Friedrich, Heiner; Gommes, Cédric ULg; de Jongh, Petra et al

Conference (2009, March)

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See detailQuantum chaos, transport, and control - In quantum optics
Madronero, Javier; Ponomarev, Alexey; Carvalho, Andre R R et al

in Advances in Atomic and Molecular Physics (2006), 53

Chaos implies unpredictability, fluctuations, and the need for statistical modelling. Quantum optics has developed into one of the most advanced subdisciplines of modern physics in terms of the control of ... [more ▼]

Chaos implies unpredictability, fluctuations, and the need for statistical modelling. Quantum optics has developed into one of the most advanced subdisciplines of modern physics in terms of the control of matter on a microscopic scale, and, in particular, of isolated, single quantum objects. Prima facie, both fields therefore appear rather distant in philosophy and outset. However, as we shall discuss in the present review, chaos, and, more specifically, quantum chaos opens up novel perspectives for our understanding of the dynamics of increasingly complex quantum systems, and of ultimate quantum control by tailoring complexity. [less ▲]

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See detailQuantum chemistry applied to the study of the beta-lactamases
Dehareng, Dominique ULg; Dive, Georges ULg

in Frère, Jean-Marie (Ed.) Beta-lactamases (2012)

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See detailQuantum Chemistry Lab at Home: A Microsoft Windows Alternative
Olive, Gilles ULg; Riffont, David

in Journal of Chemical Education (2009), 86(5), 567

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See detailQuantum Computers: A Brief Overview
Merciadri, Luca ULg

E-print/Working paper (2009)

A promising technology is the “quantum computers,” and this paper gives a general overview about this subject.

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See detailQuantum confinement and fullerenelike surface reconstructions in nanodiamonds
Raty, Jean-Yves ULg; Galli, G.; Bostedt, C. et al

in Physical Review Letters (2003), 90(3), 0374011-03740140374014

We present x-ray absorption and emission experiments and ab initio calculations showing that the size of carbon diamond must be reduced to at least 2 nm, in order to observe an increase of its optical gap ... [more ▼]

We present x-ray absorption and emission experiments and ab initio calculations showing that the size of carbon diamond must be reduced to at least 2 nm, in order to observe an increase of its optical gap, at variance with Si and Ge where quantum confinement effects persist up to 6-7 nm. In addition, our calculations show that the surface of nanodiamond particles larger than sime 1 nm reconstructs in a fullerenelike manner, giving rise to a new family of carbon clusters: bucky diamonds. Signatures of these surface reconstructions are compatible with pre-edge features observed in measured absorption spectra [less ▲]

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See detailQuantum critical 5f electrons avoid singularities in U(Ru,Rh)(2)Si-2
Silhanek, Alejandro ULg; Harrison, N.; Batista, C. D. et al

in Physical Review Letters (2005), 95(2),

We present specific heat measurements of 4% Rh-doped URu2Si2 at magnetic fields around the proposed metamagnetic transition field H(m)similar to 34 T, revealing striking similarities to the isotructural ... [more ▼]

We present specific heat measurements of 4% Rh-doped URu2Si2 at magnetic fields around the proposed metamagnetic transition field H(m)similar to 34 T, revealing striking similarities to the isotructural Ce analog CeRu2Si2 for H > H-m. This suggests that strongly renormalized hybridized-band models apply equally well to both systems. The vanishing bandwidths as H -> H-m are consistent with a quantum-critical point close to H-m. The existence of a phase transition into an ordered phase in the vicinity of H-m for 4% Rh-doped URu2Si2, but not for CeRu2Si2, is consistent with a stronger superexchange in the case of the U 5f system. Irreversible processes at the transition indicate a strong coupling of the 5f orbitals to the lattice, most suggestive of electric quadrupolar order. [less ▲]

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