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See detailAstrocytic and neuronal fate of mesenchymal stem cells expressing nestin.
Wislet-Gendebien, Sabine ULg; Wautier, Franz ULg; Leprince, Pierre ULg et al

in Brain Research Bulletin (2005), 68(1-2), 95-102

Classically, bone marrow mesenchymal stem cells (MSC) differentiate in vivo or in vitro into osteocytes, chondrocytes, fibroblasts and adipocytes. Recently, it was reported by several groups that MSC can ... [more ▼]

Classically, bone marrow mesenchymal stem cells (MSC) differentiate in vivo or in vitro into osteocytes, chondrocytes, fibroblasts and adipocytes. Recently, it was reported by several groups that MSC can also adopt a neural fate in appropriate in vivo or in vitro experimental conditions. However, it is unclear if those cells are really able to differentiate into functional neural cells and in particular into functional neurons. Some observations suggest that a cell fusion process underlies the neural fate adoption by MSC in vivo and first attempts to reproduce in vitro this neural fate decision in MSC cultures were unsuccessful. More recently, however, in several laboratories including ours, differentiation of MSC cultivated from adult rat bone marrow into astrocytes and neuron-like cells was demonstrated. More precisely, we stressed the importance of the expression by MSC of nestin, an intermediate filament protein associated with immaturity in the nervous system, as a pre-requisite to adopting an astrocytic or a neuronal fate in a co-culture paradigm. Using this approach, we have also demonstrated that the MSC-derived neuron-like cells exhibit several electrophysiological key properties classically devoted to neurons, including firing of action potentials. In this review, we will discuss the neurogenic potential of MSC, the factor(s) required for such plasticity, the molecular mechanism(s) underlying this neural plasticity, the importance of the environment of MSC to adopt this neural fate and the therapeutic potential of these observations. [less ▲]

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See detailAstroglia-Released Factor Shows Similar Effects as Benzodiazepine Inverse Agonists
Rigo, Jean-Michel; Belachew, Shibeshih ULg; Lefebvre, P. P. et al

in Journal of Neuroscience Research (1994), 39(4), 364-76

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA ... [more ▼]

Media conditioned by cultured neonatal cerebral cortex microexplants (CCM) or astrocytes (ACM) contain low molecular weight (< 1,000 Da) substance(s) which inhibits the gamma aminobutyric acid (GABA)-induced inward current recorded in cerebellar granule cells and hippocampal neurons in culture using the whole-cell patch-clamp technique. This effect is specific for CCM and ACM, as medium conditioned by PC12 cells (PC12CM) does not affect the GABA response of these cells. It is also specific for GABA-induced currents because glutamate-induced currents do not change either in amplitude or in shape in the presence of CCM or ACM. The inhibitory effect on the GABA response in cerebellar granule cells of both ACM and CCM could be suppressed by flumazenil, a specific benzodiazepine (BZD) antagonist and could be mimicked by two BZD inverse agonists. These data thus demonstrate the presence of a BZD inverse agonist-like activity in CCM and ACM. This effect of ACM on different neuronal cell types was heterogenous since no detectable effect could be observed on the GABA-induced current in GABA-responsive dorsal root ganglion (DRG) neurons, presumably reflecting a functional heterogeneity of the GABAA receptors present in these different neuronal subsets. By the release of such an endogenous BZD inverse agonist-like activity, glia cells could possibly modulate GABAA receptor-mediated responses. [less ▲]

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See detailAstroglia-released factor with negative allosteric modulatory properties at the GABA A receptor.
Rigo, Jean-Michel; Belachew, Shibeshih ULg; Coucke, Paul et al

in Biochemical Pharmacology (1996), 52(3), 465-473

We have previously shown, using whole-cell patch-clamp techniques, that astrocytes release a negative allosteric modulator of the gamma-aminobutyric acid type A receptor (GABAA receptor) with beta ... [more ▼]

We have previously shown, using whole-cell patch-clamp techniques, that astrocytes release a negative allosteric modulator of the gamma-aminobutyric acid type A receptor (GABAA receptor) with beta-carboline-like properties, thus, likely to act at the benzodiazepine site. Here, using patch-clamp and binding techniques, we confirm that the low-molecular-weight fraction of astroglia-conditioned medium (ACM lmf) contains a factor(s) that negatively modulates GABAA-receptor function. This factor, like beta-carbolines, enhances the specific binding of [35S]t-butyl bicyclophosphorothionate (TBPS) to adult rat cortical membranes in the presence of GABA. However, it fails to interact with various ligands of the benzodiazepine (BZD) site of the GABAA receptor ([3H]flunitrazepam, [3H]Ro 15-1788 and [3H]Ro 15-4513). The question of the actual binding site of the astroglia-derived factor on the GABAA receptor, thus, remains open and can be addressed only after the purification of the active molecule(s) of ACM Imf has been completed, and a labeled form of the endogenous ligand becomes available. Taken together, however, the data suggest that type 1 astrocytes are able to modulate the effects of the main inhibitory neurotransmission in the central nervous system. [less ▲]

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See detailAstroglial transformations in the developing murine cerebral wall
Caviness, V. S.; Misson, Jean-Paul ULg; Takahashi, T. et al

in Neuroscience (1989)

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See detailAstrometric orbits of SB^9 stars
Jancart, Sylvie ULg; Jorissen, A.; Babusiaux, C. et al

in Astronomy and Astrophysics (2005), 442

Hipparcos Intermediate Astrometric Data (IAD) have been used to derive astrometric orbital elements for spectroscopic binaries from the newly released Ninth Catalogue of Spectroscopic Binary Orbits (S[SUB ... [more ▼]

Hipparcos Intermediate Astrometric Data (IAD) have been used to derive astrometric orbital elements for spectroscopic binaries from the newly released Ninth Catalogue of Spectroscopic Binary Orbits (S[SUB]B^9[/SUB]). This endeavour is justified by the fact that (i) the astrometric orbital motion is often difficult to detect without the prior knowledge of the spectroscopic orbital elements, and (ii) such knowledge was not available at the time of the construction of the Hipparcos Catalogue for the spectroscopic binaries which were recently added to the S[SUB]B^9[/SUB] catalogue. Among the 1374 binaries from S[SUB]B^9[/SUB] which have an HIP entry (excluding binaries with visual companions, or DMSA/C in the Double and Multiple Stars Annex), 282 have detectable orbital astrometric motion (at the 5% significance level). Among those, only 70 have astrometric orbital elements that are reliably determined (according to specific statistical tests), and for the first time for 20 systems. This represents a 8.5% increase of the number of astrometric systems with known orbital elements (The Double and Multiple Systems Annex contains 235 of those DMSA/O systems). The detection of the astrometric orbital motion when the Hipparcos IAD are supplemented by the spectroscopic orbital elements is close to 100% for binaries with only one visible component, provided that the period is in the 50-1000 d range and the parallax is >5 mas. This result is an interesting testbed to guide the choice of algorithms and statistical tests to be used in the search for astrometric binaries during the forthcoming ESA Gaia mission. Finally, orbital inclinations provided by the present analysis have been used to derive several astrophysical quantities. For instance, 29 among the 70 systems with reliable astrometric orbital elements involve main sequence stars for which the companion mass could be derived. Some interesting conclusions may be drawn from this new set of stellar masses, like the enigmatic nature of the companion to the Hyades F dwarf HIP 20935. This system has a mass ratio of 0.98 but the companion remains elusive. [less ▲]

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See detailEl astronauta en el mesón
Ceballos Viro, Alvaro ULg

in Juan PÉREZ ZÚÑIGA, Seis días fuera del mundo (Viaje inoluntario) / Sei giorni fuori dal mondo (Viaggio involontario) (2011)

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See detailAstronomers Meet in Isfahan
Heyn, Herman M; Nazé, Yaël ULg

Article for general public (2001)

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See detailAstronomes célèbres et astronomes moins connus ... (1) William Herschel
Biémont, Emile ULg

in Galactée (2003), 34

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See detailAstronomes célèbres et astronomes moins connus ... (2) Les Cassini
Biémont, Emile ULg

in Galactée (2003), 35

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See detailAstronomes célèbres et astronomes moins connus ... (3) Hipparque
Biémont, Emile ULg

in Galactée (2003), 35

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See detailAstronomes célèbres et astronomes moins connus ... (4) Bailly
Biémont, Emile ULg

in Galactée (2004), 40

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See detailAstronomes célèbres et astronomes moins connus ... (5) Hubble
Biémont, Emile ULg

in Galactée (2004), 43

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See detailAstronomes célèbres et astronomes moins connus ... (6) John Flamsteed
Biémont, Emile ULg

in Galactée (2005), 46

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See detailThe astronomical calibration of the Givetian (Middle Devonian) time scale (Dinant Synclinorium, Belgium).
De Vleeschouwer; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in American Geophysical Union Fall Meeting, Abstract (2013)

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See detailThe astronomical calibration of the Givetian (Middle Devonian) time scale (Dinant Synclinorium, Belgium).
De Vleeschouwer; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in Whalen; Osadetz; Richards (Eds.) et al IGCP-580/596, Geophysical and Geochemical techniques: a window on the Paleozoic world, Abstract book (2013)

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See detailThe astronomical calibration of the Givetian (Middle Devonian) timescale (Dinant Synclinorium, Belgium)
De Vleeschouwer, David; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in Geological Society Special Publication (2015), 414

Recent advances in radiometric dating result in significant improvements in the geological timescale and provide better insight into the timing of various processes and evolutions within the Earth’s ... [more ▼]

Recent advances in radiometric dating result in significant improvements in the geological timescale and provide better insight into the timing of various processes and evolutions within the Earth’s system. However, no radiometric ages are contained within the Givetian. Consequently, the absolute ages of the Givetian Stage boundaries, as well as the stage’s duration, remain poorly constrained. As an alternative, the analysis of sedimentary cycles allows for the estimation of the duration of this stage. We examined the high-resolution magnetic susceptibility signals of four Givetian outcrops in the Givet area for a possible astronomical imprint, to fully understand the rates of evolutionary and environmental change. All four sections are firmly correlated and wavelet analyses of the magnetic susceptibility signals reveal the imprint of astronomical eccentricity forcing. The highly stable 405 kyr cycles constrain the duration of the Givetian Stage at 4.35+0.45 Myr, which is in good agreement with the International Chronostratigraphic Chart (5.0 Myr). The studied sections also exhibit an imprint of obliquity, suggesting a climatic teleconnection between low and high latitudes. The corresponding microfacies curves demonstrate similar astronomical imprint, and thereby indicate that the observed 10 5year-scale cyclicity is the result of climatic and environmental change [less ▲]

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See detailAstronomical Optics -- D. J. Schroeder
Manfroid, Jean ULg

in Ciel et Terre (1988), 104

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See detailAstronomical photographic atlas
Heck, Andre; Manfroid, Jean ULg

Book published by Desoer (1977)

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See detailAstronomical Photometry, A Guide
Sterken, Christiaan; Manfroid, Jean ULg

Book (1992)

Small and large telescopes are being installed all around the world. Astronomers have thus acquired better access to more modern equipment; not in the least to photometers, which are very important tools ... [more ▼]

Small and large telescopes are being installed all around the world. Astronomers have thus acquired better access to more modern equipment; not in the least to photometers, which are very important tools for the contemporary observer. This development of higher quality and more sensitive equipment makes it very necessary to improve the accuracy of the measurements. This guide helps the astronomer and astronomy student to improve the quality of their photometric measurements and to extract a maximum of information from their observations. The book is based on the authors' observing experience, spending numerious nights behind various instruments at many different observatories. [less ▲]

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See detailAn astronomical survey conducted in Belgium
Nazé, Yaël ULg; Fontaine, Sébastien ULg

in Physics Education (2014), 49

This article presents the results of the first survey conducted in Belgium about the interest and knowledge in astronomy. Two samples were studied, the public at large (667 questionnaires) and students ... [more ▼]

This article presents the results of the first survey conducted in Belgium about the interest and knowledge in astronomy. Two samples were studied, the public at large (667 questionnaires) and students (2589 questionnaires), but the results are generally similar in both samples. We evaluated people’s interest, main information source, and attitudes towards astronomy, as well as their supposed and actual knowledge of the subject. The main conclusion is that, despite a poor self-confidence, people do know the basic astronomical concepts. However, that knowledge is not deeply rooted, as reasoning questions show well-spread misconceptions and/or misunderstandings. [less ▲]

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