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See detailImaging the inner regions of debris disks with near-infrared interferometry
Defrère, D.; Absil, Olivier ULg; Augereau, J. C. et al

in EPSC-DPS Joint Meeting 2011 (2011, October 01)

Most debris disks resolved so far show extended structures located at tens to hundreds AU from the host star, and are more analogous to our solar system's dusty Kuiper belt than to the AU-scale zodiacal ... [more ▼]

Most debris disks resolved so far show extended structures located at tens to hundreds AU from the host star, and are more analogous to our solar system's dusty Kuiper belt than to the AU-scale zodiacal disk inside our solar system's asteroid belt. Over the last few years however, a few hot debris disks have been detected around a handful of main sequence stars thanks to the advance of infrared interferometry. The grain populations derived from these observations are quite intriguing, as they point towards very high dust replenishment rates, high cometary activity or major collisional events. In this talk, we review the ongoing efforts to detect bright exozodiacal disks with precision near-infrared interferometry in both hemispheres with CHARA/FLUOR and VLTI/PIONIER. We discuss preliminary statistical trends on the occurrence of bright exozodi around nearby main sequence stars and show how this information could be used to constrain the global architecture and evolution of debris disks. [less ▲]

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See detailImaging the mechanisms involved in abdominal aortic aneurysms rupture; a step towards patient-specific risk assessment
NCHIMI LONGANG, Alain ULg

Doctoral thesis (2015)

Introduction The general context of this dissertation is to evaluate patient-specifi c approaches to the risk of rupture of abdominal aortic aneurysm (AAA), using imaging techniques with ability to assess ... [more ▼]

Introduction The general context of this dissertation is to evaluate patient-specifi c approaches to the risk of rupture of abdominal aortic aneurysm (AAA), using imaging techniques with ability to assess biological processes. Following a thorough description of available imaging techniques, our work is divided in two main research objectives, namely: (i) to provide greater clinical value to existing but unproven imaging concepts, and (ii) to suggest new concepts for improved AAA risk of rupture assessment. Methods The fi rst research objective evaluated how far imaging biological activities using 18F-Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) and modeling wall stress using fi nite element simulations (FES) may help clinical decisionmaking in patients with AAA, and what would be their incremental value as compared to diameter-based patient management algorithms. On a patient basis, clinical outcomes were evaluated with regard to FDG PET and FES signaling. Further, the concept of AAA risk-equivalent diameter using FES was described and retrospectively validated using data from large multicenter trials. The second research objective included the assessment of the biological activities of the intraluminal thrombus (ILT) and the demonstration of its deleterious role in AAA using multimodality imaging. A special emphasis was put on the ability of magnetic resonance imaging (MRI) to monitor the biological activities of ILT without exogenous contrast, by evaluating its iron content. Results Increased FDG uptake was a diameter-independent marker of AAA-related events over 2 years. Missing dichotomy prevented such a fi nding for increased wall stress, although its correlation with increased FDG uptake indicates a potentially comparable value in terms of risk management. Wall metabolism is infl uenced by patient-specifi c susceptibility factors, indicating hereditary or acquired alteration of the biological responses to wall stress. The concept of risk-equivalent diameters on FES links biomechanical estimates to basic conclusions drawn from large diameter-based clinical AAA trials. Our retrospective and diameter-adjusted validation analysis verifi ed that biomechanical risk indicators are higher in ruptured than non-ruptured AAAs. Part of the FDG uptake is associated with biological activity along the luminal surface of the ILT, where we experimentally demonstrated phagocytosis of superparamagnetic iron oxide on MRI , both ex vivo and in vivo. This phagocytosis is correlated with the abundance of leukocytes and proteolytic activity. In addition, unenhanced MRI appearances resulting from the endogenous iron distribution within ILT also relate to these biological activities. Lastly, multimodality imaging was used to confi rm the concept of the deleterious role of the ILT in AAA growth in a model of AAA by infusion of elastase in the rat. Conclusion MRI and FDG PET are capable of evidencing and quantifying in vivo some of the notoriously deleterious biological processes taking place in the aneurysmal sac, especially related to the entrapped phagocytes and red blood cells in ILT and the periadventitial infl ammatory response. The central role played by ILT and its biological activities was demonstrated in vivo using several imaging techniques. The clinical value of imaging these biological activities is epitomized by a diameterindependent 2-year increased risk of event in AAA with increased wall metabolism. [less ▲]

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See detailImaging the solar corona in the EUV
Delaboudiniere, J.-P.; Stern, R. A.; Maucherat, A. et al

in Advances in Space Research (1997), 20

The SOHO (SOlar and Heliospheric Observatory) satellite was launched on December 2nd 1995. After arriving at the Earth-Sun (L1) Lagrangian point on February 14th 1996, it began to continuously observe the ... [more ▼]

The SOHO (SOlar and Heliospheric Observatory) satellite was launched on December 2nd 1995. After arriving at the Earth-Sun (L1) Lagrangian point on February 14th 1996, it began to continuously observe the Sun. As one of the instruments onboard SOHO, the EIT (Extreme ultraviolet Imaging Telescope) images the Sun's corona in 4 EUV wavelengths. The He II filter at 304 AË images the chromosphere and the base of the transition region at a temperature of 5 - 8 x 10^4 K; the Fe IX-X filter at 171 AË images the corona at a temperature of ~ 1.3 x 10^6 K; the Fe XII filter at 195 AË images the quiet corona outside coronal holes at a temperature of ~ 1.6 x 10^6 K; and the Fe XV filter at 284 AË images active regions with a temperature of ~ 2.0 x 10^6 K. About 5000 images have been obtained up to the present. In this paper, we describe also some aspects of the telescope and the detector performance for application in the observations. Images and movies of all the wavelengths allow a look at different phenomena present in the Sun's corona, and in particular, magnetic field reconnection. [less ▲]

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See detailImaging the Statics and Dynamics of Superconducting Vortices and Antivortices Induced by Magnetic Microdisks
Kramer, R. B. G.; Silhanek, Alejandro ULg; Gillijns, W. et al

in Physical Review X (2011), 1(2), 021004

If a magnet of microscopic dimensions is brought in close proximity to a superconductor, the quantized nature of their interaction due to the creation of flux quanta in the superconducting system becomes ... [more ▼]

If a magnet of microscopic dimensions is brought in close proximity to a superconductor, the quantized nature of their interaction due to the creation of flux quanta in the superconducting system becomes noticeable. Herein, we directly image, via scanning Hall microscopy, the vortex-antivortex pairs in a superconducting film created by micromagnets. The number of antivortices at equilibrium conditions can be changed either by tuning the magnetic moment of the magnets or by annihilation with externally induced vortices. We demonstrate that small ac field excitations shake the antivortices sitting next to the micromagnets whereas no sizable motion is observed for the vortices sitting on top of the magnets, clearly revealing the different mobility of these two vortex species. A metastable state, which is obtained by applying a field after the system has been cooled down below the superconducting transition, shows a complex graded distribution of coexisting vortices and antivortices forming an intertwined critical state. [less ▲]

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See detailImaging the statics and dynamics of vortex-antivortex molecules
Silhanek, Alejandro ULg

Conference (2011, September)

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See detailImaging-guided percutaneous spinal biopsy
Stulko, J.; Miezentseva, V. A.; Gerard, L. et al

in Revue Médicale de Liège (2013), 68(3), 128-33

The aim of this article is to present the value and limitations of image-guided percutaneous biopsy in spinal disorders. The indications and contraindications of percutaneous spinal biopsy and the ... [more ▼]

The aim of this article is to present the value and limitations of image-guided percutaneous biopsy in spinal disorders. The indications and contraindications of percutaneous spinal biopsy and the different techniques and materials used are discussed. The decision for this type of biopsy and the choice of technique should be made by a multidisciplinary team. Percutaneous spinal biopsy is a safe, inexpensive and possible as an outpatient. The effectiveness of percutaneous spinal biopsy is around 70%. [less ▲]

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See detailImatinib and Nilotinib Inhibit Hematopoietic Progenitor Cell Growth, but Do Not Prevent Adhesion, Migration and Engraftment of Human Cord Blood CD34+ Cells
Belle, Ludovic ULg; Bruck, France; FOGUENNE, Jacques ULg et al

in PLoS ONE (2012), 7(12), 52564

Background: The availability of tyrosine kinase inhibitors (TKIs) has considerably changed the management of Philadelphia chromosome positive leukemia. The BCR-ABL inhibitor imatinib is also known to ... [more ▼]

Background: The availability of tyrosine kinase inhibitors (TKIs) has considerably changed the management of Philadelphia chromosome positive leukemia. The BCR-ABL inhibitor imatinib is also known to inhibit the tyrosine kinase of the stem cell factor receptor, c-Kit. Nilotinib is 30 times more potent than imatinib towards BCR-ABL in vitro. Studies in healthy volunteers and patients with chronic myelogenous leukemia or gastrointestinal stromal tumors have shown that therapeutic doses of nilotinib deliver drug levels similar to those of imatinib. The aim of this study was to compare the inhibitory effects of imatinib and nilotinib on proliferation, differentiation, adhesion, migration and engraftment capacities of human cord blood CD34+ cells. Design and Methods: After a 48-hour cell culture with or without TKIs, CFC, LTC-IC, migration, adhesion and cell cycle analysis were performed. In a second time, the impact of these TKIs on engraftment was assessed in a xenotransplantation model using NOD/SCID/IL-2Rc (null) mice. <br />Results: TKIs did not affect LTC-IC frequencies despite in vitro inhibition of CFC formation due to inhibition of CD34+ cell cycle entry. Adhesion of CD34+ cells to retronectin was reduced in the presence of either imatinib or nilotinib but only at high concentrations. Migration through a SDF-1a gradient was not changed by cell culture in the presence of TKIs. Finally, bone marrow cellularity and human chimerism were not affected by daily doses of imatinib and nilotinib in a xenogenic transplantation model. No significant difference was seen between TKIs given the equivalent affinity of imatinib and nilotinib for KIT. <br />Conclusions: These data suggest that combining non-myeloablative conditioning regimen with TKIs starting the day of the transplantation could be safe. [less ▲]

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See detailImazalil modulates CYPs 1A1 and 3A4 activities in the human Caco-2 cells as an intestinal model to assess food safety
Sergent, Thérèse; Ribonnet, Laurence; Jassogne, C. et al

in Toxicology Letters (2007), 172

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See detailImbalance between lipoxin A(4) and leukotriene B-4 in chronic mastitis-affected cows
Boutet, Philippe ULg; Bureau, Fabrice ULg; Degand, Guy ULg et al

in Journal of Dairy Science (2003), 86(11), 3430-3439

Persistent accumulation of inflammatory cells in the udder, with neutrophils being the predominant cell type, is a characteristic feature of chronic mastitis in dairy cows. Leukotriene (LT) B-4 is a ... [more ▼]

Persistent accumulation of inflammatory cells in the udder, with neutrophils being the predominant cell type, is a characteristic feature of chronic mastitis in dairy cows. Leukotriene (LT) B-4 is a potent chemotactic agent, known to induce recruitment and accumulation of neutrophils in the bovine mammary gland. The LTB4-stimulated neutrophil functional responses are closely opposed by lipoxin (LX) A(4), which promotes the resolution of inflammation. We thus hypothesized that the chronic inflammation of the udder could be associated with an unfavorable ratio between these two eicosanoids and that the persistence of neutrophil accumulation could be due to an increase in LTB4 synthesis and/or an impaired LXA(4) production. In an attempt to verify this hypothesis, we first measured LXA(4), LTB4, and their ratio in the milk of healthy and acute and chronic mastitis-affected quarters. Next, we studied the relationships between these variables and the degree of udder inflammation as assessed by somatic cell count measurement. The LTB4 concentration was low in healthy quarters, drastically increased in acute mastitis, and reached intermediate levels in chronic mastitis-affected quarters. However, whereas LXA(4) concentration was highly increased in acute mastitis, healthy and chronic quarters had similarly low values. The LXA(4):LTB4 ratio was thus significantly lower in chronic mastitis-affected cows. The LTB4 concentrations measured in chronic quarters were highly correlated to somatic cell count and to milk neutrophil and macrophage numbers. A weaker correlation was observed between LXA(4) and these variables. For both eicosanoids, the highest correlation was observed with the number of neutrophils. These results show the existence of an LXA(4):LTB4 imbalance in chronic mastitis-affected cows because of low LXA(4) concentrations. Further studies are needed to determine whether administration of LX or stable analogs could have therapeutic potential in the control of chronic bovine mastitis. [less ▲]

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See detailImidazol(in)ium carboxylates as N-heterocyclic carbene ligand precursors for Suzuki-Miyaura reactions
Tudose, Adriana; Delaude, Lionel ULg; André, Benoît et al

in Tetrahedron Letters (2006), 47(48), 8529-8533

Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2 ... [more ▼]

Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2-phenylvinylboronic acid. Imidazol(in)ium carboxylates show an excellent activity, which compares to that displayed by the parent imidazol(in)ium chlorides, whereas imidazol(in)ium dithiocarboxylates are poorly efficient. Interestingly, the base employed exerts a profound influence on the trans/cis stereochemistry of the coupling product. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailImidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors for the synthesis of second generation ruthenium metathesis catalysts
Sauvage, Xavier ULg; Demonceau, Albert ULg; Delaude, Lionel ULg

in Advanced Synthesis & Catalysis (2009), 351(11-12), 2031-2038

Five well-known ruthenium-N-heterocyclic carbene (NHC) catalysts for olefin metathesis and related reactions, including the second generation Grubbs and Hoveyda-Grubbs catalysts, were prepared by ... [more ▼]

Five well-known ruthenium-N-heterocyclic carbene (NHC) catalysts for olefin metathesis and related reactions, including the second generation Grubbs and Hoveyda-Grubbs catalysts, were prepared by phosphane exchange between first generation ruthenium-benzylidene or indenylidene complexes and NHCs generated in situ upon thermolysis of imidazol(in)ium-2-carboxylates. Because N-heterocyclic carbene -carbon dioxide adducts (NHC · CO2) are stable zwitterionic compounds that can be stored and handled with no particular precautions, this procedure is particularly attractive from a practical point of view. Reaction courses were conveniently monitored by 31P NMR spectroscopy and the experimental conditions were carefully adjusted to obtain high yields of pure products within short periods of time. [less ▲]

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See detailImidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium-arene catalysts for olefin metathesis and cyclopropanation
Tudose, Adriana; Demonceau, Albert ULg; Delaude, Lionel ULg

in Journal of Organometallic Chemistry (2006), 691(24-25), 5356-5365

Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,.6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by ... [more ▼]

Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,.6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon dioxide. They were characterized by IR and NMR spectroscopies, and by TGA. Their ability to act as NHC precursors for in situ catalytic applications was probed in ruthenium-promoted olefin metathesis and cyclopropanation reactions. When visible light induced ring-opening metathesis polymerization of cyclooctene or cyclopropanation of styrene with ethyl diazoacetate were carried out at 60 degrees C in the presence of [RuCl2(p-cymene)](2), the NHC (.) CO2 adducts and their NHC (.) HX counterparts (X = Cl, BF4) displayed similar activities. When metathesis polymerizations were performed at room temperature, the carboxylates proved far superior to the corresponding imidazol(in)ium acid salts. They displayed the same level of activity as the preformed RuCl2(p-cymene)(IMes) complex, whereas the combination of NHC (.) HX and KO-t-Bu were almost totally inactive. Results obtained for cyclopropanation reactions at room temperature did not show such a large discrepancy of behavior between the two types of adducts. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailImidazolidinones structurally-related to penicillins: synthesis, molecular modeling and biological evalutation
Marchand-Brynaert, Jacqueline; Lamotte-Brasseur, Josette; Dive, Georges ULg

in Drug Metabolism and Drug Interactions (1994), 11(2), 85-109

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See detailImidazolopyrazinones as potential antioxydants
Devillers, Ingrid; Dive, Georges ULg; De Tollenaere, Catherine et al

in Bioorganic & Medicinal Chemistry Letters (2001), 11(17), 2305-2309

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See detailImiquimod et PDT dans le traitement des carcinomes basocellulaires, des kératoses actiniques et de la maladie de Bowen
Wauters, Odile ULg; Nikkels, Arjen ULg

in Dermatologie Actualité (2009), 117

Le traitement des carcinomes basocellulaires (CBC) superficiels, des petits CBC nodulaires, des kératoses actiniques (KA) et de la maladie de Bowen soit par imiquimod soit par photothérapie dynamique (PDT ... [more ▼]

Le traitement des carcinomes basocellulaires (CBC) superficiels, des petits CBC nodulaires, des kératoses actiniques (KA) et de la maladie de Bowen soit par imiquimod soit par photothérapie dynamique (PDT) est actuellement bien ancré dans l'arsenal thérapeutique du dermatologue. Les réussites thérapeutiques de ces deux modalités sont incontestables et avoisinent les 80 % dans les deux cas. Chaque méthode est liée à des effets indésirables propres et inhérents aux différents mécanismes d'action. Cette revue compare les données de la littérature évaluant l'efficacité, le taux de récidive, la tolérance, et les résultats cosmétiques pour les différentes indications reconnues en Belgique. Afin de mieux pouvoir cerner le niveau de preuve scientifique des études, le niveau d'évidence des publications est également mentionné. Ensuite seront discutés les avantages et les limites de ces techniques en pratique quotidienne. [less ▲]

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See detailImiquimod-responsive basal cell carcinomas and factor XIIIa-enriched dendrocytes.
Quatresooz, Pascale ULg; Pierard, Gérald ULg

in Clinical & Experimental Dermatology (2003), 28 Suppl 1

Dermal dendrocytes (DDs) are dendritic cells that exhibit immunoreactivity for factor XIIIa, and are frequently found in conjunction with basal cell carcinomas (BCCs). Imiquimod was applied to 12 ... [more ▼]

Dermal dendrocytes (DDs) are dendritic cells that exhibit immunoreactivity for factor XIIIa, and are frequently found in conjunction with basal cell carcinomas (BCCs). Imiquimod was applied to 12 superficial BCCs every 3 days for 8 weeks. One week after completion of treatment, seven lesions appeared to have resolved, while five displayed evidence of residual BCC. Prior to initiation of treatment, the seven imiquimod-responsive BCCs were surrounded by numerous DDs, whereas the five imiquimod-resistant BCCs had fewer DDs next to them at the time of entry into the study. It appears that the pretreatment density in DDs may affect the efficacy of imiquimod in eradicating skin tumours. [less ▲]

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See detailIMISCOE Research Network, Training and Research Inventory
Gsir, Sonia ULg

Report (2011)

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See detailIMISCOE Research Network, Training and Research Inventory
Gsir, Sonia ULg

Report (2012)

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