Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailL'utilisation des insectes dans la pharmacopée de l'Égypte gréco-romaine
Marganne, Marie-Hélène ULg

Conference (2015, September 11)

Telles qu'on peut les déchiffrer dans les papyrus littéraires grecs retrouvés en Égypte (IV/IIIe siècles avant notre ère – VI/VIIe siècles de notre ère), les prescriptions médicales recourent-elles à des ... [more ▼]

Telles qu'on peut les déchiffrer dans les papyrus littéraires grecs retrouvés en Égypte (IV/IIIe siècles avant notre ère – VI/VIIe siècles de notre ère), les prescriptions médicales recourent-elles à des insectes et, si tel est le cas, à quelle(s) variété(s), en raison de quelle(s) propriété(s) et pour quel(s) type(s) d'affections ? C'est à ces questions que l'on tentera de répondre, en complétant le témoignage des sources papyrologiques par celui des sources littéraires grecques et latines sur la pharmacopée de l'Égypte gréco-romaine. [less ▲]

Detailed reference viewed: 28 (1 ULg)
Peer Reviewed
See detailWill Big Data Deliver its Promised Productivity Growth?
Artige, Lionel ULg

Conference (2015, September 11)

Detailed reference viewed: 27 (0 ULg)
Peer Reviewed
See detailPredator cues and risky habitats affect foraging activity in salamanders
Melotto, Andrea; Ficetola, Gentile Francesco; Denoël, Mathieu ULg et al

Conference (2015, September 11)

Detailed reference viewed: 12 (0 ULg)
See detailIntercalation of imidazolium end-functionalized polyphosphates between montmorillonite nanosheets towards flame-retardant
Carion, Stéphan ULg; Lecomte, Philippe ULg; Thomassin, Jean-Michel ULg et al

Poster (2015, September 11)

Among the additives used to impart flame-retardant properties to polymer materials, phosphorous additives and nanoclays are widely used. The aim of this work is to associate both additives to bring about ... [more ▼]

Among the additives used to impart flame-retardant properties to polymer materials, phosphorous additives and nanoclays are widely used. The aim of this work is to associate both additives to bring about a synergetic effect for improving the flame-retardancy of the material (1). In a first step, the synthesis of an aliphatic polyphosphate end-capped by an imidazolium cation is reported. Secondly, this polymer is intercalated between montmorillonite nanoclays. The strategy used for the synthesis of the polyphosphate is based on the ring-opening polymerization of the corresponding cyclic phosphate by using 1-(11-hydroxy-undecyl)-3-methylimidazolium bromide as an initiator. This polymerization was catalyzed by DBU and a thiourea derivative (2). This polymer was characterized by a set of techniques (31P and 1H NMR, SEC, TGA, DSC). Finally, the cationic end-functionalized polymer was exchanged with sodium cations present in montmorillonite. The intercalation of the polyphosphate between the clay nanosheets was proved by X-Ray Diffraction (XRD) and thermogravimetric analysis (TGA). This last technique was also used to determine the influence of the intercalation on the thermal stability of the polyphosphate. [less ▲]

Detailed reference viewed: 27 (5 ULg)
See detailGreen synthesis of polyphosphoesters, a promising class of bioinspired degradable materials
Lecomte, Philippe ULg; Baeten, Evelien

Conference (2015, September 11)

Detailed reference viewed: 19 (3 ULg)
Full Text
See detailOptimized focal and pupil plane masks for vortex coronagraphs on telescopes with obstructed apertures
Ruane, Garreth; Absil, Olivier ULg; Huby, Elsa ULg et al

in Shaklan, Stuart (Ed.) Techniques and Instrumentation for Detection of Exoplanets VII (2015, September 11)

We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex ... [more ▼]

We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance pupil, focal plane, and the plane of the Lyot stop. Optimal masks are obtained using both analytical and numerical methods. The latter makes use of an iterative error reduction algorithm to calculate "correcting" optics that mitigate unwanted diffraction from aperture obstructions. We analyze the achieved performance in terms of starlight suppression, contrast, off-axis image quality, and chromatic dependence. Manufacturing considerations and sensitivity to aberrations are also discussed. This work provides a path to joint optimization of multiple coronagraph planes to maximize sensitivity to exoplanets and other faint companions. [less ▲]

Detailed reference viewed: 18 (7 ULg)
Full Text
See detailA Mach-Zehnder interferometer based on orbital angular momentum for improved vortex coronagraph efficiency
Piron, Pierre ULg; Delacroix, Christian; Huby, Elsa ULg et al

in Shaklan, Stuart (Ed.) Techniques and Instrumentation for Detection of Exoplanets VII (2015, September 11)

The Annular Groove Phase Mask (AGPM) is a vectorial vortex phase mask. It acts as a half-wave plate with a radial fast axis orientation operating in the mid infrared domain. When placed at the focus of a ... [more ▼]

The Annular Groove Phase Mask (AGPM) is a vectorial vortex phase mask. It acts as a half-wave plate with a radial fast axis orientation operating in the mid infrared domain. When placed at the focus of a telescope element provides a continuous helical phase ramp for an on axis sources, which creates the orbital angular momentum. Thanks to that phase, the intensity of the central source is canceled by a down-stream pupil stop, while the off axis sources are not affected. However due to experimental conditions the nulling is hardly perfect. To improve the null, a Mach-Zehnder interferometer containing Dove prisms differently oriented can be proposed to sort out light based on its orbital angular momentum (OAM). Thanks to the differential rotation of the beam, a π phase shift is achieved for the on axis light affected by a non zero OAM. Therefore the contrast between the star and its faint companion is enhanced. Nevertheless, due the Dove prisms birefringence, the performance of the interferometer is relatively poor. To solve this problem, we propose to add a birefringent wave-plate in each arm to compensate this birefringence. In this paper, we will develop the mathematical model of the wave front using the Jones formalism. The performance of the interferometer is at first computed for the simple version without the birefringent plate. Then the effect of the birefringent plate is be mathematically described and the performance is re-computed. [less ▲]

Detailed reference viewed: 20 (4 ULg)
Peer Reviewed
See detailCe que l'image fait à l'histoire
Havelange, Carl ULg

Conference (2015, September 11)

Detailed reference viewed: 14 (0 ULg)
See detailClinical significance of MT4-MMP and EGFR expression in Breast Cancer
Yip, Cassandre ULg; PAYE, Alexandra ULg; Truong, Alice ULg et al

Scientific conference (2015, September 11)

Detailed reference viewed: 11 (5 ULg)
See detailNovel organocobalt for the synthesis of functional polymers
Demarteau, Jérémy ULg; Kermagoret, Anthony; Jérôme, Christine ULg et al

Poster (2015, September 11)

Organocobalt(III) with acetylacetonate (acac) ligands is the most representative example of R-Co bearing a labile C-Co bond that can release alkyl radicals under mild experimental conditions without ... [more ▼]

Organocobalt(III) with acetylacetonate (acac) ligands is the most representative example of R-Co bearing a labile C-Co bond that can release alkyl radicals under mild experimental conditions without requiring a photoactivation. The unique isolated R-Co is a short oligo(vinyl acetate) end-capped by Co(acac)2. The high lability of its C-Co bond combined to the unique capacity of Co(acac)2 to reversibly trap alkyl radicals make this R-Co unique for the precision design of unprecedented polymers by Cobalt-Mediated Radical Polymerization (CMRP). The growth of unstabilized and highly reactive growing radicals formed by the addition of R• to unconjugated vinyl monomers (vinyl esters, vinyl amides, vinyl imidazolium, vinyl chloride, etc;) is controlled by the reversible formation of a weak C-Co bond at the polymer chain end. The lack of alternatives to this R-Co, especially to the structure of the alkyl group, has however placed limitations on post-functionalizations of end-chains. Other functional variants that would enable attractive chain-end derivatizations are unfortunately not available. In this poster, we will address this important challenge by describing an innovative synthetic route towards the preparation of new functional R-Co(acac)2 that are sources of halomethyl radicals under mild experimental conditions. The efficiency of these novel organocobalt complexes for the precision synthesis of end-functional and telechelic polymers will be described. Also, the solubility of these complexes in water enables the facile production of end-functionalized water soluble poly(ionic liquid)s. Further derivatizations of the halomethyl group at the chain-end of polymers produced by this system will be demonstrated by click reaction, largely broadening the range of possible functional groups. Finally, besides numerous applications in macromolecular engineering, this unexplored family of R-Co presents a high potential in radical reactions in organic synthesis by the facile production of halomethyl radicals. [less ▲]

Detailed reference viewed: 40 (3 ULg)
Full Text
Peer Reviewed
See detailTentativi di avvicinamento a Il figlio di Bakunìn (1991) di Sergio Atzeni (1952-1995)
Curreri, Luciano ULg

Conference (2015, September 11)

Detailed reference viewed: 47 (6 ULg)
Full Text
See detailCobalt-mediated radical polymerization for the precision design of novel poly(ionic liquid) copolymers in aqueous media
Cordella, Daniela ULg; Kermagoret, Anthony; Debuigne, Antoine ULg et al

Poster (2015, September 11)

Poly(ionic liquid)s (PILs) have emerged as a special class of polyelectrolyte materials, featuring tunable solubility, high ionic conductivity, and a broad range of glass transition temperatures. Due to ... [more ▼]

Poly(ionic liquid)s (PILs) have emerged as a special class of polyelectrolyte materials, featuring tunable solubility, high ionic conductivity, and a broad range of glass transition temperatures. Due to their specific properties emanating from the ionic liquid (IL) units and their intrinsic polymeric nature, PILs find potential applications in various areas, such as analytical chemistry, biotechnology, gas separation, dispersants, solid ionic conductors for energy, catalysis, etc. In recent years, controlled radical polymerization (CRP) techniques have been applied to the synthesis of structurally well-defined PILs, with control attained over molar mass, dispersity, and end-group fidelity. In this poster, we will report on the implementation of cobalt-mediated radical polymerization (CMRP) technique for the precision synthesis of unprecedented PILs (co)polymers. We will discuss how an organocobalt complex can efficiently control the growth of vinyl imidazolium chains and lead to PILs with predicted molar masses and low polydispersities under mild experimental conditions, thus at low temperature and using water as a green polymerization medium. The huge potential of this system will be highlighted by describing the one-pot synthesis of all vinyl imidazolium-based block copolymers in aqueous media. This CMRP is unique for providing well-defined vinyl imidazolium based-copolymers for advanced PILs applications. [less ▲]

Detailed reference viewed: 35 (3 ULg)
See detailNew efficient organocatalytic system for solvent-free chemical fixation of CO2 into epoxides
Panchireddy, Satyannarayana ULg; Gennen, Sandro ULg; Alves, Margot ULg et al

Poster (2015, September 11)

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and ... [more ▼]

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and industrial fields. To date, the chemical fixation of CO2 onto epoxides with the formation of cyclic carbonates (CC) is one of the most promising ways to valorise CO2 at an industrial scale. Indeed, CC are useful monomers for polycarbonate synthesis and they can react with primary amines to produce 2-hydroxyethylurethane. This reaction can be extrapolated to the synthesis of non-isocyanate polyurethanes (NIPUs) by a step growth polymerization between bifunctional CC and diamines. [less ▲]

Detailed reference viewed: 67 (3 ULg)
Full Text
See detailInstitutional repositories: it’s a matter of sticks and carrots
Rentier, Bernard ULg

E-print/Working paper (2015)

Detailed reference viewed: 218 (10 ULg)
Full Text
See detailIdentification et caractérisation des progéniteurs pancréatiques et des précurseurs endocrines durant l'embryogenèse chez le poisson-zèbre
Ghaye, Aurélie ULg

Doctoral thesis (2015)

Le diabète survient lorsque le nombre ou la fonction des cellules β, productrices d’insuline est affecté. Le nombre de personnes atteintes par cette maladie croît de manière impressionnante d’année en ... [more ▼]

Le diabète survient lorsque le nombre ou la fonction des cellules β, productrices d’insuline est affecté. Le nombre de personnes atteintes par cette maladie croît de manière impressionnante d’année en année. Bien qu’il puisse être contrôlé par des injections régulières d’insuline, ce traitement est contraignant, coûteux et ne permet pas d’éliminer toute une série d’effets secondaires chez le patient diabétique. Un des challenges à l’heure actuelle est de développer des stratégies qui permettraient de remplacer ces cellules. La régénération in vivo constitue une approche thérapeutique attrayante. Cependant, cette régénération est peu efficace chez les mammifères et un défi majeur consisterait à la stimuler. Contrairement aux mammifères, le poisson-zèbre (Danio rerio), est un modèle de choix pour étudier la régénération puisqu’il possède le remarquable pouvoir de régénérer les cellules β rapidement et efficacement après leur ablation ciblée. Néanmoins, il est important d’identifier et de caractériser les cellules pancréatiques qui donnent naissance aux cellules β afin de connaître l'ensemble des facteurs et voies de signalisation contrôlant leur formation. Le but de mon doctorat s’est inscrit dans cette démarche d’identification et de caractérisation des cellules progénitrices. Pour ce faire, nous avons généré deux lignées transgéniques qui nous ont permis de suivre le destin des cellules exprimant le facteur de transcription Nkx6.1 et Ascl1b. Par des expériences de traçage de lignée, nous avons montré que les cellules Nkx6.1+ marquent des progéniteurs pancréatiques qui donnent naissance à toutes les lignées pancréatiques alors que les cellules Ascl1b marquent des précurseurs endocrines qui ne donnent naissance qu’à la lignée endocrine. Nous avons aussi montré qu’au début du développement pancréatique, les deux facteurs sont exprimés dans les mêmes cellules pancréatiques puis se séparent rapidement. Cette ségrégation n’est pas la conséquence d’une répression mutuelle entre Ascl1b et Nkx6.1 mais est due à un effet opposé de la voie de signalisation Notch qui maintient l’expression de nkx6.1 et réprime l’expression d’ascl1b. [less ▲]

Detailed reference viewed: 48 (6 ULg)
Full Text
See detailOsteopontin as a new target in glioblastoma progression and resistance to radiotherapy
Henry, Aurélie ULg; Bellahcene, Akeila ULg; Castronovo, Vincenzo ULg et al

Conference (2015, September 10)

Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments ... [more ▼]

Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments include maximal surgical resection, radiotherapy and concomitant or adjuvant chemotherapy with Temozolomide (TMZ). However, the prognosis of adult patients with GBM remains poor and the survival outcome after treatment does not exceed 15 months. Glioblastoma-composing cells have developed many strategies to counteract these current therapies. Among the wide hallmarks acquired to survive, osteopontin (OPN) ranks correlates with lower overall and disease-free/relapse-free survival in all tumors combined, as well in brain cancer. OPN expression is largely considered as a molecular cancer marker associated with poor prognosis for patients with cancer. Our preliminary works (Lamour V and Henry A, IJC 2015) have demonstrated the role of OPN in the tumorigenicity of glioblastoma cells and its importance in the maintenance of the stem charachters. Within the continuance of this work, our recent studies focused on the potential role of OPN in the resistance of glioblastoma cells to radiotherapy and its implication in the initiation of Double Strand Breaks (DSBs) repair mechanism. In this context, U251-MG and U87-MG cells were used to assess the role of OPN in the initiation of the DSBs repair mechanism after an exposure to gamma-irradiation (γ–IR). The transient transfection of both cell lines with siRNA directed against OPN shown a lower induction of γ–H2AX compared to control (irrelevant siRNA). The survival of U251-OPN depleted cells was also affected after an exposure to γ–IR (based on clonogenic assays). However, the sole depletion of OPN in U87 cells affected their survival (independently of the γ–IR). To prove that the secreted form of OPN is necessary to survive after γ–IR, conditionned medium of U87-shSCR clones (rich in OPN) was used to treat U87shOPN clones before an exposure to γ–IR. By immunofluorescence, we observed that the γ–H2AX staining was higher in U87 shOPN clones than when treated with their own conditionned medium (poor in OPN). Currently, we are investigating the in vivo implication of OPN in the initiation of DSBs repair mechanism after an exposure of mice to γ–IR (whole brain exposure). For this purpose, IPTG-inducible U87 shRNA clones (SCR and OPN) have been generated and validated for an orthotopic xenograft model in NOD-SCID mice. The survival after a radiotherapy of 10 Gy (2Gy per day for 5 days) will be assessed in OPN-positive and –negative tumor-bearing mice. Taken together, these datas suggest that OPN could represent an important pronostic factor for patient response to radiotherapy in the context of GBM. [less ▲]

Detailed reference viewed: 62 (21 ULg)