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See detailCFD Large Eddy Simulation of the hydrodynamics of stirred mini-bioreactors operating with stem cell culture mixing conditions
Collignon, Marie-Laure ULg; Martin, Céline; Toye, Dominique ULg et al

Poster (2015, January 18)

The expansion of hMSC adhered on microcarriers is a proven technology to allow the production of quantitatively (cell density and growth rate) and qualitatively (preservation of cell stemness) the amounts ... [more ▼]

The expansion of hMSC adhered on microcarriers is a proven technology to allow the production of quantitatively (cell density and growth rate) and qualitatively (preservation of cell stemness) the amounts of cells required for clinical applications. In that context of process optimization, a platform of 6 parallel 250 mL stirred minibioreactors have been designed and fully equipped for hMSC cultivation on microcarriers. The local hydrodynamics in these bioreactors have been characterized using CFD simulations and experimental measurements. GOALS: 1) Evaluation of the flexibility of the platform for extensively studying the coupling between hydrodynamics and hMSC physiological response (growth, stemness) by changing agitation conditions. 2) Evaluation of the scale down ability of platform as prediction tool of the hMSC behavior in larger bioreactor scale. [less ▲]

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See detailCFD Modelisation of homogeneous distribution of solid particles in a stirred tank
Calvo, Sébastien ULg; Delafosse, Angélique ULg; Collignon, Marie-Laure ULg et al

Poster (2013, April 24)

In this work, we study the conditions needed to reach homogeneous distribution of solid particles of aluminium salts in water inside a torospherical bottom shaped stirred tank reactor of 70L equipped with ... [more ▼]

In this work, we study the conditions needed to reach homogeneous distribution of solid particles of aluminium salts in water inside a torospherical bottom shaped stirred tank reactor of 70L equipped with a Pfaudler RCI type impeller and three equi-spaced vertical baffles. The aim of the present study is to develop a CFD model describing the quality of particle distribution in industrial scale tanks. This model, validated with experimental data, is afterward used to developed scale-up and scale-down correlations to predict the minimum impeller speed needed to reach homogeneous solid distribution Nhs. The commercial CFD software Fluent 14 is used to model the fluid flow and the solid particle distribution in the tank. The 3D geometry of the tank and the associated mesh are respectively realized by Ansys 14 DesignModeler and Meshing. The Sliding-Mesh approach is used to take the impeller motion into account. Assuming that the discrete solid phase has no influence on the continuous liquid phase behaviour, the fluid flow dynamics may be simulated independently using the well-known k-ε turbulence model. The behaviour of the liquid-solid mixture is then described by implementing the Eulerian Mixture model. Liquid velocity fields simulated by CFD have been validated by comparison with PIV (Particle Image Velocimetry) measurements. Computed values of Nhs are compared with good agreement to experimental data obtained with a nephelometric probe. Results obtained at different scales allowed correlating the Nhs value to the volumetric power consumption. [less ▲]

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See detailCFD-based Compartment model for description of mixing in bioreactors
Delafosse, Angélique ULg; Calvo, Sébastien ULg; Collignon, Marie-Laure ULg et al

in Chemical Engineering Science (2014), 106

In most bioprocesses, it is fundamental to accurately predict the hydrodynamics behavior of bioreactors of different size and its interaction with the biological reaction. Computational Fluid Dynamics can ... [more ▼]

In most bioprocesses, it is fundamental to accurately predict the hydrodynamics behavior of bioreactors of different size and its interaction with the biological reaction. Computational Fluid Dynamics can provide detailed modeling about hydrodynamics and mixing. However, it is computationally intensive, especially when reactions are taken into account. Another way to predict hydrodynamics is the use of “Compartment” or “Network-of-zones” model which are much less demanding in computation time than CFD. However, compartments and fluxes between them are often defined by considering global quantities not representative of the flow complexity. To overcome the limitations of these two methods, a solution is to combine compartment modeling and CFD simulations. The aim of this study is to propose a compartment model where the flow rates between two adjacent compartments are easily computed from the velocity fields obtained by CFD. The mixing evolution predicted by the CFD-based compartment model have been then compared with mixing experiment results. Unlike a CFD mixing simulation and a classical compartment model, the CFD-based compartment model proposed in this work reproduces with a good accuracy the spatial distribution of concentrations during the mixing process and this, without any adjustable parameters. [less ▲]

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See detailCFD-gestütztes Design von Drehscheibenextraktoren
Aksamija, E; Weinländer, C; Pfennig, Andreas ULg et al

in Chemie Ingenieur Technik (2012), 84(8), 1262

Detailed reference viewed: 5 (0 ULg)
See detailCFIP'97 Ingénierie des protocoles
Leduc, Guy ULg

Book published by Hermès (1997)

Detailed reference viewed: 15 (1 ULg)
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See detailCFTR and defective endocytosis: new insights in the renal phenotype of cystic fibrosis.
JOURET, François ULg; Devuyst, Olivier

in Pflügers Archiv : European Journal of Physiology (2009), 457(6), 1227-36

Inactivation of the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) causes cystic fibrosis (CF). Although CFTR is expressed in the kidney, no overwhelming renal phenotype is ... [more ▼]

Inactivation of the chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) causes cystic fibrosis (CF). Although CFTR is expressed in the kidney, no overwhelming renal phenotype is associated with CF. Recent studies have shown that the level of CFTR mRNA in mouse kidney approaches that found in lung. CFTR is particularly abundant in the apical area of proximal tubule cells, where it co-distributes with the Cl(-)/H(+) exchanger ClC-5 and Rab5a in endosomes. The biological relevance of CFTR in proximal tubule endocytosis has been tested in CF mouse models and CF patients. Mice lacking CFTR show a defective receptor-mediated endocytosis, as evidenced by impaired uptake of (125)I-beta(2)-microglobulin, a decreased expression of the cubilin receptor in the kidney, and a significant excretion of cubilin and its low-molecular-weight ligands into the urine. Low-molecular-weight proteinuria (and particularly transferrinuria) is similarly detected in CF patients in comparison with normal controls or patients with chronic lung inflammation. These studies suggest that the functional loss of CFTR impairs the handling of low-molecular-weight proteins by the kidney, supporting a role of CFTR in receptor-mediated endocytosis in proximal tubule cells. The selective proteinuria should be integrated in the pathophysiology of multi-systemic complications increasingly observed in CF patients. [less ▲]

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See detailCGMS/WOFOST model principles
Tychon, Bernard ULg

Conference (2005, November)

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See detailCH4 and N2O may contribute more to greenhouse effect than CO2 emission from the SCS
Tseng; Chen, C-TA; Borges, Alberto ULg et al

Conference (2014, November 17)

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See detailChablis et risques sanitaires
Riguelle, Simon ULg

Learning material (2011)

Detailed reference viewed: 10 (5 ULg)
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See detailChablis et risques sanitaires
Riguelle, Simon ULg

Learning material (2012)

Detailed reference viewed: 18 (6 ULg)
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See detailChagall, Ensor, de Vlaminck, Laurencin : artistes « dégénérés » aux Collections artistiques de l’Université de Liège
Reynders, Stéphanie ULg

in Duchesne, Jean-Patrick (Ed.) L’art dégénéré selon Hitler. La vente de Lucerne, 1939 (2014)

Detailed reference viewed: 8 (0 ULg)
See detailChagar Bazar (Syrie) I:Les sondages préhistoriques (1999-2001)
Tunca, Önhan ULg; Baghdo, Abd el-Massih

Book (2006)

Detailed reference viewed: 42 (3 ULg)
See detailChagar Bazar (Syrie) II:Les vestiges « post-akkadiens » du chantier D et études diverses
Tunca, Önhan ULg; McMahon, A.; Baghdo, Abd el-Massih

Book (2007)

Detailed reference viewed: 72 (11 ULg)
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See detailChain end effects and dewetting in thin polymer films
Henn, G.; Bucknall, D. G.; Stamm, Manfred et al

in Macromolecules (1996), 29(12), 4305-4313

The dewetting of thin films of end-functionalized polymers, ω- and α,ω-barium sulfonato polystyrenes, on a silicon substrate has been investigated as a function of initial film thickness, molecular weight ... [more ▼]

The dewetting of thin films of end-functionalized polymers, ω- and α,ω-barium sulfonato polystyrenes, on a silicon substrate has been investigated as a function of initial film thickness, molecular weight, and functionality of the chains. The lower molecular weight monofunctional chains are found to dewet the substrate analogously to normal polystyrene but display an anomalous flow behavior at the surface. Moreover, after dewetting, the entire silicon surface still remains covered by a monolayer of monofunctional chains. The monolayer consists of a polymer brush of densely packed tethered chains, adsorbed via their ionic end groups. The dense packing and special conformations of the chains in the brush prevent interpenetration with other polymer chains, and the unadsorbed macromolecules dewet the brush. When the molecular weight of the monofunctional chains is increased, entanglements between the adsorbed polymer brush and the unadsorbed chains can occur and the dewetting process is retarded. Thin films of the difunctional chains do not dewet regardless of the molecular weight of the chains. The difference between mono- and difunctional materials is attributed to ionic aggregation, which is responsible for thermoreversible cross-linking and stabilization of thicker films by interaction of aggregates with dangling ends. It is suggested to use high molecular weight end-functionalized chains as polymeric additives to retard thin polymer film dewetting. [less ▲]

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See detailLe chaînon manquant. Lotze, Cook Wilson et la naissance du réalisme d'Oxford
Boccaccini, Federico ULg

Scientific conference (2012, January)

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See detailChair
Martiniello, Marco ULg

Scientific conference (2009, February 16)

Detailed reference viewed: 5 (0 ULg)
Peer Reviewed
See detailchair and member of scientific committee
Geenen, Kristien ULg

Conference (2016)

Detailed reference viewed: 11 (0 ULg)