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See detailTomographie pinhole au MIBI-Tc99m dans l’hyperparathyroïdie primaire: comparaison des reconstructions iterative et analytique.
Carlier, Thomas; Oudoux, A.; Bodet-Milin, C. et al

in Médecine Nucléaire : Imagerie Fonctionnelle et Métabolique (2006), 30(09), 519

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See detailAdmittance spectroscopy of semiconductor structures
Nguyen, Ngoc Duy ULg

Scientific conference (2006)

Admittance spectroscopy is a powerful tool for electrical characterization of semiconductor structures such as p-n junctions, Schottky diodes, light-emitting systems or quantum wells. It consists in ... [more ▼]

Admittance spectroscopy is a powerful tool for electrical characterization of semiconductor structures such as p-n junctions, Schottky diodes, light-emitting systems or quantum wells. It consists in monitoring the complex admittance of the overall device under test as a function of frequency, applied dc voltage and temperature. This technique gives direct access to the emission-capture processes occurring between an impurity level and the conduction or the valence band and leads to the determination of important electronic properties including the activation energy and the carrier capture cross sections. However, the interpretation of the admittance curves is straightforward only under restrictive assumptions such as full ionization of the shallow dopant, with a concentration larger than the deep impurity concentration. Numerical simulations, based on the solution of the basic semiconductor equations, allow to carry out a detailed analysis of the steady-state and small-signal electrical characteristics of the systems and thus contribute to a better understanding of the conduction mechanisms and of the microscopic origin of the features in the experimental admittance spectra. In this presentation, the results obtained for three different structures are shown in order to illustrate the method. In the first case, the role of Mg in GaN Schottky diodes is investigated. The results of the study show that this acceptor has simultaneously the functions of dopant and of deep impurity. In order to explain the electrical behavior of Mg, thermal admittance spectroscopy measurements are performed on Schottky structures based on Mg-doped GaN layers grown by metalorganic vapor phase epitaxy on sapphire. The analysis is carried out by simulating the electrical characteristics of the device. The calculated curves fully reproduce the experimental results and the microscopic parameters are determined by an optimized fitting procedure, based on the comparison of the electrical characteristics obtained from the numerical simulations to those of the experiment. In the second example, charge-carrier mobility in organic materials is evaluated. The frequency- dependent complex admittance and impedance of the structure consisting of the organic layer, grown by thermal evaporation and sandwiched by metallic electrodes, are measured as functions of the dc bias. The capacitance-versus-frequency curve exhibits a minimum, the frequency-position of which increases with the applied dc voltage. Based on numerical calculations, the theoretical analysis shows that the inductive contribution to the capacitance originates from the modulation of the free carrier concentration in the organic material. The finite carrier transit time determines the frequency-response of the structure. Moreover, the low-frequency behavior of the capacitance curves can be explained by the presence of a band of defect states that modifies the charge distribution within the device. As third application of the admittance spectroscopy method, the electrical characteristics of an organic light-emitting diode are numerically simulated for the dc and the ac regimes. This approach allows to obtain a detailed microscopic description of the dependences of the carrier concentrations and current densities on the applied steady-state voltage and the modulation frequency. The fitting of the resulting admittance and impedance curves to the response of an equivalent electrical circuit shows that each element can be associated with a particular region of the structure. It is then possible to correlate the dependence of each feature of the admittance and impedance curves with one or several parameters of the material system. [less ▲]

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See detailProposal to the Eurocode 3 for the lateral-torsional buckling of stainless steel I-beams in case of fire
Lopes, N.; Vila Real, P. M. M.; Simoes da Silva, L. et al

in Vila Real, P. M. M. (Ed.) Proceedings of the 4th International Workshop Structures in Fire (2006)

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See detailNumerical validation of an improved proposal to the Eurocode 3 for lateral-torsional buckling of steel beams subjected to fire
Vila Real, P. M. M.; Lopes, N.; Simoes da Silva, L. et al

in Vila Real, P. M. M. (Ed.) Proceedings of the 4th International workshop Structures in Fire (2006)

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See detailL'oral au quotidien : pistes de réflexion et d'action pour l'enseignement du langage oral au cycle 2 ans 1/2 à 5 ans.
Hindryckx, Geneviève ULg

Book published by Centre technique et pédagogique de la Communauté française (2006)

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See detailÉtude morphologique et immunocytologique du développement prénatal de l’organe de Corti chez le rat.
Thelen, Nicolas ULg

Master of advanced studies dissertation (2006)

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See detailETUDE COMPARATIVE DE LA COMPOSITION CHIMIQUE DE LA NIGELLA SATIVA LINN. DE PLUSIEURS REGIONS DU MONDE EXTRAITES PAR MICRO-ONDES
Benkaci-Ali, Farid; Baaliouamer, Aoumeur; Wathelet, Jean-Paul ULg et al

in Rivista italiana EPPOS (2006), 41

The Nigella Sativa, eastern plant from the Mediterranean basin and other areas of the world, is very much used as condiment and medicinal application. The microwave extraction allows to obtain oils in a ... [more ▼]

The Nigella Sativa, eastern plant from the Mediterranean basin and other areas of the world, is very much used as condiment and medicinal application. The microwave extraction allows to obtain oils in a very short time and with a better quality and yields. The GC and GC/MS analysis of oils shows that are rich in volatile of biosynthesis compounds such as the p-cymene and the thymoquinone which have medicinal properties. The undesirable products caused by the reactions of hydrolysis and the heating effect such as acids, alcohols and oxides are relatively reduced. The monoterpenes and ketones constitute the principal classes of our oils. In addition, the analytical study reveals that the seeds cultivated in the arid regions are rich in thymoquinone which constitutes the principal active component of Nigella Sativa seeds . [less ▲]

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See detailNumerical simulation of impedance and admittance of OLEDs
Nguyen, Ngoc Duy ULg; Schmeits, Marcel

in Physica Status Solidi : A. Applications and Materials Science (2006), 203

The electrical characteristics of organic light-emitting devices are calculated for the dc and ac regimes by numerically solving the basic semiconductor equations under steady-state and small-signal ... [more ▼]

The electrical characteristics of organic light-emitting devices are calculated for the dc and ac regimes by numerically solving the basic semiconductor equations under steady-state and small-signal conditions. For a given structure, the dc and ac electric potential and electric field, the electron and hole concentrations, as well as the different components of the current density are obtained as function of the one-dimensional spatial coordinate. This approach allows a detailed microscopic description of the dependencies of these quantities on the applied steady-state voltage V0 and the frequency of the modulating voltage. The final output consists in the frequency-dependent complex admittance and impedance of the device, the real and imaginary parts of which are the experimentally-available data. As a typical example, we show the results for a two-layer structure where α-NPD is the hole-transporting material and Alq3 the electron-transporting material. The anode is made of ITO and Al/LiF composes the cathode. The admittance and impedance curves, yielded by the numerical simulation as functions of the modulation frequency, are fitted by an equivalent electrical circuit, the elements of which are resistances and capacitances. The number of com- ponents depends on the structure composition and on the applied steady-state voltage. We show that each element can be associated with a particular region of the device. This allows to correlate the dependence of each feature of the admittance and impedance curves with one or several parameters describing the ma- terial system. Such an analysis can be useful for the inverse approach, where, starting from measurements of the electrical ac characteristics, the aim is to get information on the microscopic mechanisms which contribute to the electrical conduction of the device. [less ▲]

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See detailComparative responses to sodium selenite and Sel-Plex® organic selenium supplements in Belgian Blue cows and calves
Guyot, Hugues ULg; Rollin, Frédéric ULg; Andrieu, Sylvie et al

in Nutritional Biotechnology in the Feed and Food Industries (Alltech’s 22nd Annual Symposium) (2006)

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See detailPost-ischemic hypothermia reduced IL-18 expression and suppressed microglial activation in the immature brain.
Fukui, On; Kinugasa, Yukiko; Fukuda, Aya et al

in Brain Research (2006), 1121(1), 35-45

Inflammation is an important factor for hypoxia-ischemia (HI) brain injury. Interleukin (IL)-18 is a proinflammatory cytokine which may be a contributor to injury in the immature brain after HI. To ... [more ▼]

Inflammation is an important factor for hypoxia-ischemia (HI) brain injury. Interleukin (IL)-18 is a proinflammatory cytokine which may be a contributor to injury in the immature brain after HI. To investigate the effects of post-HI hypothermia on IL-18 in the developing brain, 7-day-old rats were subjected to left carotid artery ligation followed by 8% oxygen for 60 min and divided into a hypothermia group (rectal temperature 32 degrees C for 24 h) and a normothermia group (36 degrees C for 24 h). The IL-18 mRNA was analyzed with real-time RT-PCR, and the protein level was analyzed by Western blot, and the location and source of IL-18 were assessed by immunohistochemistry. The significant increase of the IL-18 mRNA was observed in the ipsilateral hemispheres of the normothermia group at 24 h and 72 h after HI compared with controls, but the level in the ipsilateral hemispheres of the hypothermia group was significantly reduced at both time points, compared with the normothermia group, respectively. The IL-18 protein level in the ipsilateral hemispheres of the normothermia group significantly increased at 72 h after HI compared with controls, however, the protein level of the hypothermia group was significantly decreased, compared with the normothermia group. IL-18-positive cells were observed throughout the entire cortex, corpus callosum (CC) and striatum in the ipsilateral hemispheres of normothermia group at 72 h after HI, however, little positive cells were observed in the hypothermia group. Double labeling immunostaining found that most of the IL-18-positive cells were colocalized with lectin, which is a marker of microglia. The number of ameboid microglia (AM) in the normothermia group was significantly increased in cortex and CC, compared with the number in controls, but there were very few ramified microglia (RM) in these areas. In contrast, the number of AM in the hypothermia group was significantly decreased in cortex and CC, compared with the number in the normothermia group, and there were no significant differences in the number of AM and RM between the hypothermia group and controls. In conclusion, we found that IL-18 mRNA and the protein level were attenuated by post-HI hypothermia and that post-HI hypothermia may decrease microglia activation in the developing brain. [less ▲]

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See detailCancer risk and bariatric surgery
De Roover, Arnaud ULg; Desaive, Claude; Detry, Olivier ULg et al

in Obesity Surgery (2006), 16

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See detailSociologie de la famille. Notes de cours provisoires
Guillaume, Jean-François ULg

Learning material (2006)

Présentation des grands paradigmes théoriques en sociologie de la famille, et des problématiques liés à la constitution du lien conjugal et à l'éducation parentale. Avec, en introduction, un rappel des ... [more ▼]

Présentation des grands paradigmes théoriques en sociologie de la famille, et des problématiques liés à la constitution du lien conjugal et à l'éducation parentale. Avec, en introduction, un rappel des fondements de l'analyse sociologique (destiné aux étudiants n'ayant pas de formation initiale en sociologie). [less ▲]

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See detailEditorial Report 2005
Denoël, Mathieu ULg

in Amphibia-Reptilia (2006), 27(3), 479

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See detailIrreversible passive energy transfer in coupled oscillators with essential nonlinearity
Kerschen, Gaëtan ULg; Lee, Young Sup; Vakakis, Alexander F. et al

in SIAM Journal on Applied Mathematics (2006), 66(2), 648-679

We study numerically and analytically the dynamics of passive energy transfer from a damped linear oscillator to an essentially nonlinear end attachment. This transfer is caused by either fundamental or ... [more ▼]

We study numerically and analytically the dynamics of passive energy transfer from a damped linear oscillator to an essentially nonlinear end attachment. This transfer is caused by either fundamental or subharmonic resonance capture, and in some cases is initiated by nonlinear beat phenomena. It is shown that, due to the essential nonlinearity, the end attachment is capable of passively absorbing broadband energy at both high and low frequencies, acting, in essence, as a passive broadband boundary controller. Complicated transitions in the damped dynamics can be interpreted based on the topological structure and bifurcations of the periodic solutions of the underlying undamped system. Moreover, complex resonance capture cascades are numerically encountered when we increase the number of degrees of freedom of the system. The ungrounded essentially nonlinear end attachment discussed in this work can find application in numerous practical settings, including vibration and shock isolation of structures, seismic isolation,. utter suppression, and packaging. [less ▲]

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See detailEvaluation de la mesure "Prairie de haute valeur biologique - MAE8" en région agricole Fagne-Famenne
Rouxhet, Serge ULg; Walot, Thierri

Report (2006)

Durant l'été 2006, l'évaluation a été axée uniquement sur la mesure agri-environnementale "méthode 8 - prairie de haute valeur biologique" en région agricole Fagne-Famenne. Un échantillon de 43 parcelles ... [more ▼]

Durant l'été 2006, l'évaluation a été axée uniquement sur la mesure agri-environnementale "méthode 8 - prairie de haute valeur biologique" en région agricole Fagne-Famenne. Un échantillon de 43 parcelles au sein de 34 exploitations a été évalué. [less ▲]

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See detailField evaluation of poor performance in Standardbred trotters
Van Erck, Emmanuelle; Jakesova, V.; Lekeux, Pierre ULg et al

in Pferdeheilkunde (2006), 22

Exercise tests allow evaluating athletic capacity and fitness, following training-induced adaptations and determining causes of poor performance. A retrospective study was conducted over the cases of 40 ... [more ▼]

Exercise tests allow evaluating athletic capacity and fitness, following training-induced adaptations and determining causes of poor performance. A retrospective study was conducted over the cases of 40 poor performing Standardbreds referred to an Equine Sports Medicine consultation at a Belgian racetrack. The study aimed at determining if the implementation of a standardised exercise test and determination of specific athletic parameters could discriminate between the poor performers and a group of eight healthy racehorses and help in establishing a diagnosis. After a through clinical examination, the horses were submitted to an exercise test that consisted of 3 bouts of 1500m at increasing speeds with a recovery phase of 500 m in between. Speed and heart rate were continuously monitored and blood lactate concentrations were evaluated after each step. Pre and post-effort blood work and respiratory endoscopy with sampling were done in each horse. Five main causes of poor performance were identified: locomotor, respiratory, cardiac, muscular problems and inadequate training. In the poor performers group, 24 horses suffered from upper and/or lower respiratory disease, 20 from lameness, 4 from cardiac disease, 4 from exercise-induced myopathy and 5 from maladjusted training. More than half of the horses had multiple problems (23 horses). The fitness parameters (V-LA4, V-200) obtained were useful for inter-individual comparisons and discriminated poor performers from healthy controls, whatever the cause of the intolerance. This study confirms the high prevalence of lameness and respiratory diseases as causes of poor performance in racehorses. The field exercise tests were readily performed with minimal equipment and enabled to identify conditions which were not clearly apparent as during the clinical examination at rest. The recovery of maximum information by a thorough questioning of the trainer and selected ancillary examinations was critical to reach a diagnosis. [less ▲]

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