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See detailHighly efficient organic/inorganic titania xerogels for photocatalysis applications
Bodson, Céline ULg; Bied, Catherine; Páez Martínez, Carlos ULg et al

Poster (2011)

TiO2 heterogeneous photocatalysis is an attractive technique for the complete destruction of undesirable contaminants either in aqueous or gaseous phase by using solar or artificial light illumination ... [more ▼]

TiO2 heterogeneous photocatalysis is an attractive technique for the complete destruction of undesirable contaminants either in aqueous or gaseous phase by using solar or artificial light illumination. The main drawback of TiO2 is that it can be activated only by UV light because of its large band gap (3.20 eV for anatase). Thus, it would be interesting to sensitize TiO2 to the whole visible region by doping with non-metal atoms such as phosphorus. Furthermore, it was found that the P-doped species could significantly increase the specific surface area of the materials, which consequently exhibit a higher content of surface hydroxyl groups. Upon band gap excitation of TiO2, the photoinduced electrons and positively charged holes can reduce and oxidize the species adsorbed on the TiO2 particles. The high degree of recombination between photogenerated electrons and holes is a major rate-limiting factor controlling the photocatalytic efficiency. Attempts to increase the titania efficiency have been made by doping P-doped TiO2 with metals, such as Ag. In the present study, a sol-gel method is developed to synthesize P-doped TiO2 and P/Ag-codoped xerogels by a cogelation method [1] based on the hydrolysis and the condensation of Ti(OC3H7)4 in the presence of a phosphoryled compound able to complex silver: NH2-(CH2)2-NH-(CH2)2-P(O)-(OC2H5)2, EDAP), in various alcohols. These xerogels are dried at 150°C under vacuum for 24 h, and calcined under air for 5 h at 350°C, 450°C, 550°C and 650°C. The resulting materials were characterized by ICP-AES, TG-DSC, TEM, XRD, nitrogen adsorption-desorption isotherms, FT-IR and diffuse reflectance measurements in the UV/Vis region. To measure the photoactivity of these new hybrid organic/inorganic titania xerogels, all these samples were tested for the degradation of p-nitrophenol under visible light. The titanium, phosphorus and silver contents in xerogels were confirmed by ICP-AES. As expected, theoretical and actual Ti/P molar ratio and Ag contents in xerogels are similar and then after washing with THF for 48 h. These results allow to conclude that EDAP and Ag are well incorporated within the TiO2 matrix: EDAP is anchored in the titania matrix by complexation and cogelation with TTIP [2], whereas silver, first incorporated by complexation through the ethylenediamine fragment of EDAP, is present in the xerogels in the form of nanoparticles. It was found that the phosphor-doped species could significantly increase the surface area of the materials. [2] It is noteworthy that the porosity of these materials is not affected by the addition of silver acetate during the synthesis, a very slight decrease of the specific surface area being observed in all cases. The organic/inorganic hybrid titania materials display very high photocatalytic efficiencies in the degradation of p-nitrophenol compared to pure titania. Deeper investigations concerning the structure of these materials should enable a better understanding of the photocatalytic mechanisms involved with these hybrids and will soon be reported. 1. S. Lambert, K. Y. Tran, G. Arrachart, F. Noville, C. Henrist, C. Bied, J. J. E. Moreau, M. Wong Chi Man, B. Heinrichs, Micropor. Mesopor. Mater. 2008, 115, 609. 2. C.J.Bodson1, S.D. Lambert1, C. Alié1, X. Cattoën2, J-P. Pirard1, C. Bied2, M.Wong Chi Man2, B. Heinrichs1 ,Micropor. Mesopor. Mater. 2010, 134,157 [less ▲]

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See detailPrincipes d’hygiène et de management de la qualité sanitaire et phytosanitaire
Schiffers, Bruno ULg; Moreira, Christine

Learning material (2011)

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See detailTrente ans de politique scientifique en Wallonie 1980-2010
Halleux, Robert ULg; Pirot, Pascal ULg

Book published by Editions de l'Université de Liège (2011)

En août 1980, des lois de révision de la Constitution belge rendaient les Régions compétentes pour la recherche dite appliquée. Cet ouvrage, publié à l’occasion du trentième anniversaire de la création ... [more ▼]

En août 1980, des lois de révision de la Constitution belge rendaient les Régions compétentes pour la recherche dite appliquée. Cet ouvrage, publié à l’occasion du trentième anniversaire de la création des institutions régionales, tente d’esquisser les lignes de force, les grands axes ainsi que les enjeux passés, actuels et à venir de la politique de recherche wallonne. [less ▲]

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See detailConvergence of Logic of Cellular Regulation in Different Premalignant Cells by an Information Theoretic Approach
Kravchenko-Balasha, N.; Remacle, Françoise ULg; Gross, A. et al

in BMC Systems Biology (2011), 5

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See detailConstraining statistical-model parameters using fusion and spallation reactions
Mancusi, D.; Charity, R. J.; Cugnon, Joseph ULg

in European Physics Journal: Web of conferences (2011)

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See detailOptimization of multibody systems and their structural components
Bruls, Olivier ULg; Lemaire, Etienne ULg; Duysinx, Pierre ULg et al

in Blajer, W.; Arczewski, K.; Fraczek, J. (Eds.) et al Multibody Dynamics: Computational Methods and Applications (2011)

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a ... [more ▼]

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a nonlinear finite element formulation, a time integration scheme and a sensitivity analysis and it can be efficiently exploited in an optimization loop. In particular, the paper focuses on the topology optimization of structural components embedded in multibody systems. Generally, topology optimization techniques consider that the structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. In contrast, we show that an optimization directly based on the dynamic response of the flexible multibody system leads to a more integrated approach. The method is applied to truss structural components. Each truss is represented by a separate structural universe of beams with a topology design variable attached to each one. A SIMP model (or a variant of the power law) is used to penalize intermediate densities. The optimization formulation is stated as the minimization of the mean compliance over a time period or as the minimization of the mean tip deflection during a given trajectory, subject to a volume constraint. In order to illustrate the benefits of the integrated design approach, the case of a two degrees-of-freedom robot arm is developed. [less ▲]

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See detailInfluence of veneer thickness on residual stress profile in veneering ceramic: Measurement by hole-drilling.
MAINJOT, Amélie ULg; Schajer, G. S.; Vanheusden, Alain ULg et al

in Dental Materials (2011)

OBJECTIVES: The veneering process of frameworks induces residual stresses and can initiate cracks when combined with functional stresses. The stress distribution within the veneering ceramic as a function ... [more ▼]

OBJECTIVES: The veneering process of frameworks induces residual stresses and can initiate cracks when combined with functional stresses. The stress distribution within the veneering ceramic as a function of depth is a key factor influencing failure by chipping. This is a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the influence of veneer thickness on the stress profile in zirconia- and metal-based structures. METHODS: The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The stress profile was measured in bilayered disc samples of 20mm diameter, with a 1mm thick zirconia or metal framework. Different veneering ceramic thicknesses were performed: 1mm, 1.5mm, 2mm, 2.5mm and 3mm. RESULTS: All samples exhibited the same type of stress vs. depth profile, starting with compressive at the ceramic surface, decreasing with depth up to 0.5-1.0mm from the surface, and then becoming compressive again near the framework, except for the 1.5mm-veneered zirconia samples which exhibited interior tensile stresses. Stresses in the surface of metal samples were not influenced by veneer thickness. Variation of interior stresses at 1.2mm from the surface in function of veneer thickness was inverted for metal and zirconia samples. SIGNIFICANCE: Veneer thickness influences in an opposite way the residual stress profile in metal- and in zirconia-based structures. A three-step approach and the hypothesis of the crystalline transformation are discussed to explain the less favorable residual stress development in zirconia samples. [less ▲]

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See detailUnderstanding Crystallization of Anatase into Binary SiO2/TiO2 Sol-Gel Optical Thin Films: An in Situ Thermal Ellipsometry Analysis
Louis, B.; Krins, Natacha ULg; Faustini, M. et al

in Journal of Physical Chemistry C: Nanomaterials, Interfaces, and Hard Matter (2011), 115

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See detailHydrogeological study of Somes-Szamos transboundary alluvial aquifer
Drobot, Radu; Szucs, Peter; Brouyère, Serge ULg et al

in Ganoulis, Jacques; Aureli, Alice; Fried, Jean (Eds.) Transboundary Water Resources Management: A Multidisciplinary Approach (2011)

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See detailTrabectedine (ET-743/Yondelis) dans le traitement des sarcomes des tissus mous et du cancer de l'ovaire.
GENNIGENS, Christine ULg; Jerusalem, Guy ULg

in Revue Médicale de Liège (2011), 66(7-8), 452-5

Soft tissue sarcomas account for 1% of all malignant tumours. Until a few years ago, doxorubicine and ifosfamide were the only active chemotherapy drugs in the metastatic setting. Recently, a new drug has ... [more ▼]

Soft tissue sarcomas account for 1% of all malignant tumours. Until a few years ago, doxorubicine and ifosfamide were the only active chemotherapy drugs in the metastatic setting. Recently, a new drug has proven its efficacy after failure of standard treatments: the trabectedin; its activity is based on interference with ADN repair mechanisms. Trabectedin has just been also validated and reimbursed in patients with ovarian cancer, in partially sensitive recurrence. In this paper, we will review the mechanism of action and the clinical results of trabectedin. [less ▲]

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See detailcompte rendu de : Giuseppe ARICÒ – Massimo RIVOLTELLA (Ed.), La riflessione sul teatro nella cultura romana
Rochette, Bruno ULg

in Antiquité Classique : Revue Interuniversitaire d'Etudes Classiques (2011)

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See detailMicro-CT-based improvement of geometrical and mechanical controllability of selective laser melted Ti6Al4V porous structures
Van Bael, S.; Kerckhofs, Greet ULg; Moesen, M. et al

in MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING (2011), 528(24), 7423-7431

Despite the fact that additive manufacturing (AM) techniques allow to manufacture complex porous parts with a controlled architecture, differences can occur between designed and as-produced morphological ... [more ▼]

Despite the fact that additive manufacturing (AM) techniques allow to manufacture complex porous parts with a controlled architecture, differences can occur between designed and as-produced morphological properties. Therefore this study aimed at optimizing the robustness and controllability of the production of porous Ti6Al4V structures using selective laser melting (SLM) by reducing the mismatch between designed and as-produced morphological and mechanical properties in two runs. In the first run, porous Ti6Al4V structures with different pore sizes were designed, manufactured by SLM, analyzed by microfocus X-ray computed tomography (micro-CT) image analysis and compared to the original design. The comparison was based on the following morphological parameters: pore size, strut thickness, porosity, surface area and structure volume. Integration of the mismatch between designed and measured properties into a second run enabled a decrease of the mismatch. For example, for the average pore size the mismatch decreased from 45% to 5%. The demonstrated protocol is furthermore applicable to other 3D structures, properties and production techniques, powder metallurgy, titanium alloys, porous materials, mechanical characterization, tomography. (C) 2011 Elsevier B.V. All rights reserved. [less ▲]

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See detailBenthic remineralization in the northwest European continental margin (northern Bay of Biscay)
Suykens, Kim; Schmidt, Sabine; Delille, Bruno ULg et al

in Continental Shelf Research (2011), 31

We report a dataset of sediment characteristics and biogeochemical fluxes at the watersediment interface at the northwest European continental margin (northern Bay of Biscay). Cores were obtained in June ... [more ▼]

We report a dataset of sediment characteristics and biogeochemical fluxes at the watersediment interface at the northwest European continental margin (northern Bay of Biscay). Cores were obtained in June 2006, May 2007 and 2008, at 18 stations on the shelf break (120 to 180 m), and at 2 stations on the continental slope (520 m and 680 m). Water-sediment fluxes of dissolved oxygen (O2), total alkalinity (TA), nitrate (NO3-), and dissolved silicate (DSi) were measured at a total of 20 stations. Sediment characteristics include: grain size, chlorophyll-a (Chl-a) and phaeopigment (Phaeo) content, particulate organic (POC) and inorganic (PIC) carbon content, and lead-210 (210Pb) and thorium-234 (234Th) activities. Sediments were sandy (fine to coarse) with organic matter (OM) (1.0 - 4.0 %) and Chl-a (0.01 - 0.95 μg g-1) contents comparable to previous investigations in the same region, and a relatively high PIC fraction (0.8 - 10.2 %). Water-sediment O2 fluxes (-2.4 to -8.4 mmol O2 m-2 d-1) were low compared to other coastal environments and correlated well with OM and Chl-a content. 234Th activity profiles indicated that Chl-a sediment content was mainly controlled by physical mixing processes related to local hydrodynamics. The correlation between water-sediment fluxes of O2 and NO3- indicated a close coupling of nitrification/denitrification and total benthic organic carbon degradation. Dissolution of biogenic silica (0.05 to 0.95 mmol m-2 d-1) seemed uncoupled from organic carbon degradation, as characterized by water-sediment O2 fluxes. The link between water-sediment fluxes of TA and O2 indicated the occurrence of metabolic driven dissolution of calcium carbonates (CaCO3) in the sediments (~ 0.33 ± 0.47 mmol m-2 d-1) which represented ~ 1 % of the pelagic calcification rates due to coccolithophores measured during the cruises. These CaCO3 dissolution rates were below those reported in sediments of continental slopes and of the deep ocean, probably due to the high over-saturation with respect to CaCO3 of the water column overlying the continental shelf sediments of the northern Bay of Biscay. Rates of total benthic organic carbon degradation were low compared to water column rates of primary production and aphotic community respiration obtained during the cruises. [less ▲]

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See detailRelationship between bone mineral density changes and risk of fractures among patients receiving calcium with or without vitamin D supplementation: a meta-regression
Rabenda, Véronique ULg; Bruyère, Olivier ULg; Reginster, Jean-Yves ULg

in Osteoporosis International (2011), 22

Surrogate measures of fracture risk, such as effects on bone mineral density, may be of great interest to assess the efficacy of available osteoporosis treatments. Our results suggest that bone mineral ... [more ▼]

Surrogate measures of fracture risk, such as effects on bone mineral density, may be of great interest to assess the efficacy of available osteoporosis treatments. Our results suggest that bone mineral density (BMD) changes cannot be used as a surrogate of anti-fracture efficacy, among patients receiving calcium, with or without vitamin D. Introduction: The purpose of this study is to examine the association between changes in bone mineral density with reduction in the risk of fractures in patients receiving calcium with or without vitamin D. Methods: We selected all randomized placebo-controlled clinical trials of calcium with or without vitamin D supplementation. To be included in this analysis, the studies were required to report both BMD (hip/proximal femur and/or lumbar spine) and the incidence of fractures. Metaregression analyses were used to examine the associations of changes in BMD with reduction in risk of fracture over the duration of each study. The change in BMD was the difference between changes (from baseline) observed in the active treatment group and placebo group. Results: A total of 15 randomized trials (n=47,365) were identified, most of whom (77%) came from the Women’s Health Initiative trial. Results show that larger increases in BMD at the lumbar spine were not associated with greater reduction in fracture risk. Concerning hip BMD changes, we found a statistically significant relationship between hip BMD changes and reduction in risk. However, results were not quite significant after excluding the both largest studies, in which BMD changes were measured in very small subset of patients. These points may have largely biased our results. Conclusions: In conclusion, there was no evidence of a relationship between BMD changes and reduction in risk of fractures among patients receiving calcium with or without vitamin D supplementation. Calcium and/or Vitamin D may reduce fracture rates through a mechanism independent of bone density. [less ▲]

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See detailControl of hydrogen photoproduction by the proton gradient generated by cyclic electron flow in Chlamydomonas reinhardtii.
Tolleter, Dimitri; Ghysels, Bart ULg; Alric, Jean et al

in Plant Cell (2011), 23(7), 2619-30

Hydrogen photoproduction by eukaryotic microalgae results from a connection between the photosynthetic electron transport chain and a plastidial hydrogenase. Algal H(2) production is a transitory ... [more ▼]

Hydrogen photoproduction by eukaryotic microalgae results from a connection between the photosynthetic electron transport chain and a plastidial hydrogenase. Algal H(2) production is a transitory phenomenon under most natural conditions, often viewed as a safety valve protecting the photosynthetic electron transport chain from overreduction. From the colony screening of an insertion mutant library of the unicellular green alga Chlamydomonas reinhardtii based on the analysis of dark-light chlorophyll fluorescence transients, we isolated a mutant impaired in cyclic electron flow around photosystem I (CEF) due to a defect in the Proton Gradient Regulation Like1 (PGRL1) protein. Under aerobiosis, nonphotochemical quenching of fluorescence (NPQ) is strongly decreased in pgrl1. Under anaerobiosis, H(2) photoproduction is strongly enhanced in the pgrl1 mutant, both during short-term and long-term measurements (in conditions of sulfur deprivation). Based on the light dependence of NPQ and hydrogen production, as well as on the enhanced hydrogen production observed in the wild-type strain in the presence of the uncoupling agent carbonyl cyanide p-trifluoromethoxyphenylhydrazone, we conclude that the proton gradient generated by CEF provokes a strong inhibition of electron supply to the hydrogenase in the wild-type strain, which is released in the pgrl1 mutant. Regulation of the trans-thylakoidal proton gradient by monitoring pgrl1 expression opens new perspectives toward reprogramming the cellular metabolism of microalgae for enhanced H(2) production. [less ▲]

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See detailUrinary NGAL measurement : Biological variation and ratio to creatinine
Delanaye, Pierre ULg; Rozet, Eric ULg; Krzesinski, Jean-Marie ULg et al

in Clinica Chimica Acta (2011), 412(3-4), 390

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See detailValdeblore (06) Le Clouté
Pagès, Gaspard ULg

in D.R.A.C., S.R.A. (Ed.) Bilan scientifique de la région Provence-Alpes-Côte d’Azur 2010 (2011)

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