Publications ORBi OA
Bookmark and Share    
Full Text
Peer Reviewed
See detailFreeze-dried poly(D,L-lactic acid) macroporous guidance scaffolds impregnated with brain-derived neurotrophic factor in the transected adult rat thoracic spinal cord
Patist, Carla M; Borgerhoff Mulder, Masha; Gautier, Sandrine et al

in Biomaterials (2004), 25(9), 1569-1582

The effects of poly(D,L-lactic acid) macroporous guidance scaffolds (foams) with or without brain-derived neurotrophic factor (BDNF) on tissue sparing, neuronal survival, axonal regeneration, and ... [more ▼]

The effects of poly(D,L-lactic acid) macroporous guidance scaffolds (foams) with or without brain-derived neurotrophic factor (BDNF) on tissue sparing, neuronal survival, axonal regeneration, and behavioral improvements of the hindlimbs following implantation in the transected adult rat thoracic spinal cord were studied. The foams were embedded in fibrin glue containing acidic-fibroblast growth factor. One group of animals received fibrin glue with acidic-fibroblast growth factor only. The foams were prepared by a thermally induced polymer-solvent phase separation process and contained longitudinally oriented macropores connected to each other by a network of micropores. Both foams and fibrin only resulted in a similar gliotic and inflammatory response in the cord-implant interfaces. With BDNF foam, up to 20% more NeuN-positive cells in the spinal nervous tissue close to the rostral but not caudal spinal cord-implant interface survived than with control foam or fibrin only at 4 and 8 weeks after implantation. Semithin plastic sections and electron microcopy revealed that cells and axons more rapidly invaded BDNF foam than control foam. Also, BDNF foam contained almost twice as many blood vessels than control foam at 8 weeks after implantation. Tissue sparing was similar in all three implantation paradigms; approximately 42% of tissue was spared in the rostral cord and approximately 37% in the caudal cord at 8 weeks post grafting. The number of myelinated and unmyelinated axons was low and not different between the two types of foams. Many more axons were found in the fibrin only graft. Serotonergic axons were not found in any of the implants and none of the axons regenerated into the caudal spinal cord. The behavioral improvements in the hindlimbs were similar in all groups. These findings indicated that foam is well tolerated within the injured spinal cord and that the addition of BDNF promotes cell survival and angiogenesis. However, the overall axonal regeneration response is low. Future research should explore the use of poly(D,L-lactic acid) foams, with or without axonal growth-promoting factors, seeded with Schwann cells to enhance the axonal regeneration and myelination response. [less ▲]

Detailed reference viewed: 85 (0 ULg)
Full Text
Peer Reviewed
See detailHD 108: The mystery deepens with XMM-Newton observations
Nazé, Yaël ULg; Rauw, Grégor ULg; Vreux, Jean-Marie ULg et al

in Astronomy and Astrophysics (2004), 417(2), 667-677

In 2001, using a large spectroscopic dataset from an extensive monitoring campaign, we discovered that the peculiar Of star HD 108 displayed extreme line variations. This strange behaviour could be ... [more ▼]

In 2001, using a large spectroscopic dataset from an extensive monitoring campaign, we discovered that the peculiar Of star HD 108 displayed extreme line variations. This strange behaviour could be attributed to a variety of models, and an investigation of the high energy properties of HD 108 was needed to test the predictions from these models. Our dedicated XMM-Newton observation of HD 108 shows that its spectrum is well represented by a two temperature thermal plasma model with kT(1) similar to 0.2 keV and kT(2) similar to 1.4 keV. In addition, we find that the star does not display any significant short-term changes during the XMM-Newton exposure. Compared to previous Einstein and ROSAT detections, it also appears that HD 108 does not present long-term flux variations either. While the line variations continue to modify HD 108's spectrum in the optical domain, the X-ray emission of the star appears thus surprisingly stable: no simple model is for the moment able to explain such an unexpected behaviour. Thanks to its high sensitivity, the XMM-Newton observatory has also enabled the serendipitous discovery of 57 new X-ray sources in the field of HD 108. Their properties are also discussed in this paper. [less ▲]

Detailed reference viewed: 25 (5 ULg)
Full Text
Peer Reviewed
See detailLe syndrome de Boerhaave
Honore, Pierre ULg; De Roover, Arnaud ULg; Detry, Olivier ULg et al

in Revue Médicale de Liège (2004), 59(4), 203-4

Spontaneous rupture of the oesophagus, so called Boerhaave's syndrome, still remains a surgical emergency. Early diagnosis governs the appropriate repair and the vial prognosis.

Detailed reference viewed: 83 (6 ULg)
Full Text
Peer Reviewed
See detailPrise en charge des exacerbations d'asthme
Mommens, Véronique; Louis, Renaud ULg; D'Orio, Vincenzo ULg

in Revue Médicale de Liège (2004), 59(4), 209-14

Asthma exacerbations constitute a common medical emergency, which in the past has been shown to be poorly managed. Although its management has recently improved, it remains suboptimal. For instance, acute ... [more ▼]

Asthma exacerbations constitute a common medical emergency, which in the past has been shown to be poorly managed. Although its management has recently improved, it remains suboptimal. For instance, acute life-threatening asthma is still responsible for 2000 death each year in France. More than two thirds of deaths should be avoided by a prompt and adjusted treatment. Initial assessment of the severity of the exacerbation is fundamental. The clinical story, physical examination and objective measurement of airflow obstruction by peak flow meter should permit to quickly establish an adapted treatment. The aim of this paper is, once general considerations about clinical approach and currently used treatments have been made, to propose a home and a hospital-based management of the asthma exacerbations. [less ▲]

Detailed reference viewed: 44 (2 ULg)
Full Text
Peer Reviewed
See detailSimulation of the acoustics of coupled rooms by numerical resolution of a diffusion equation
Valeau, Vincent; Picaut, Judicaël; Sakout, Anas et al

Conference (2004, April)

Over the last few years, some studies showed that the acoustic energy density in closed or semi-closed spaces may be the solution of a diffusion equation. This theory allows non-uniform repartition of ... [more ▼]

Over the last few years, some studies showed that the acoustic energy density in closed or semi-closed spaces may be the solution of a diffusion equation. This theory allows non-uniform repartition of energy, and is especially relevant in room acoustics for long rooms or complex spaces such as networks of rooms. In this work, the three-dimensional diffusion equation is solved directly by using a finite-element solver. This approach is used to simulate the acoustics of coupled rooms in terms of spatial variations of intensity levels and sound decay. The obtained results match satisfactorily with a model based on the classical statistical theory of room acoustics, but it allows to perform a finer spatial description of the acoustics of coupled rooms. [less ▲]

Detailed reference viewed: 48 (0 ULg)
Full Text
Peer Reviewed
See detailJets instabilities producing the slot-tone
Billon, Alexis ULg; Valeau, Vincent; Sakout, Anas

Conference (2004, April)

The nature of the instability governing the self-sustained tones produced by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is identified experimentally. The ... [more ▼]

The nature of the instability governing the self-sustained tones produced by a low Mach number free plane jet impinging on a slotted plate, known as slot-tone, is identified experimentally. The experimental apparatus permits to control the Reynolds number and the distance from the jet outlet to the plate. For a Reynolds number, the shear-layer natural frequency and the jet column mode frequency of the free jet without the obstacle are estimated and compared to the minimal and maximal frequencies of the tones (for any position of the plate). The frequency of both instabilities defines the frequency domain of the self sustained tones. The lowest frequencies of the tones, obtained when the plate is placed downstream the end of the potential core, are the result of the amplification of the column mode frequency. On the other hand, the maximal frequency of the tones, obtained when the plate is situated near the jet outlet, is close to the natural shear-layer frequency. Moreover, when the tones frequency is higher than the natural shear-layer frequency, the sound pressure level produced is very inferior to the maximal sound pressure level measured at the same Reynolds number. This confirms the prominent role of the shear-layer instability in the self-sustained tones process for the highest frequencies. Tones with a frequency lower than the jet column mode frequency are rarely observed. [less ▲]

Detailed reference viewed: 20 (1 ULg)
Full Text
See detailOn Dictatorship, Economic Development and Stability
Artige, Lionel ULg

Conference (2004, April)

Detailed reference viewed: 23 (2 ULg)
Full Text
Peer Reviewed
See detailPartial encryption of images for real-time applications
Van Droogenbroeck, Marc ULg

in Fourth IEEE Signal Processing Symposium (2004, April)

Multimedia systems mostly base security on a restricted access to services. In the context of real-time imaging applications, this model suffers several drawbacks. Applications become vulnerable to ... [more ▼]

Multimedia systems mostly base security on a restricted access to services. In the context of real-time imaging applications, this model suffers several drawbacks. Applications become vulnerable to password attacks and once exposed attackers have access to all the data. An alternative consists of the systematic encryption of all data. When dealing with images, this approach is inconvenient because the data needs to be processed in its entirety before users can gain any insight. As well, the decryption task requires large amounts of processing power. This presentation shows how partial encryption can match applications requirements without the overhead of full encryption. The paper rst analyzes several schemes mixing encryption and image encoding. Then we focus on a technique that implements partial encryption of images based on JPEG. The technique is built to meet two major requirements: (1) preserve the overall bitrate, and (2) remain compliant with the JPEG file format. Finally we introduce and elaborate on a new scheme that combines flexibility, multiple encryption, spatial selectivity, self sufficiency, and format compliance. We show how it could fit the needs of real-time applications. [less ▲]

Detailed reference viewed: 139 (2 ULg)
Full Text
Peer Reviewed
See detailBiochemostratigraphy of the Devonian-Carboniferous boundary Global Stratotype Section and Point, Griotte Formation, La Serre, Montagne Noire, France
Brand, U.; Legrand-Blain, M.; Streel, Maurice ULg

in Palaeogeography Palaeoclimatology Palaeoecology (2004), 205(3-4), 337-357

The Griotte Formation and the base of Bed 89 exposed at La Serre, Montagne Noire, France represent the Global Stratotype Section and Point (GSSP) for the Devonian-Carboniferous (D-C) boundary. This study ... [more ▼]

The Griotte Formation and the base of Bed 89 exposed at La Serre, Montagne Noire, France represent the Global Stratotype Section and Point (GSSP) for the Devonian-Carboniferous (D-C) boundary. This study represents the geochemical work on brachiopods and matrix covering the Siphonodella praesulcata to Siphonodella sulcata Zones at the GSSP. Values of Sr-87/Sr-86 of unaltered brachiopods provide the most powerful biochemostratigraphic tool in recognizing and correlating the Devonian-Carboniferous boundary on a global scale. The frequency and variations of the latest Devonian Sr-87/Sr-86 trend (0.708167 +/- 0.000042) are invariant but the population means are similar (p = 1.000) to the essentially pronounced trend for the post-boundary Carboniferous (0.708165 +/- 0.000054) brachiopods from the GSSP and supplementary sections. The Devonian-Carboniferous boundary Sr-87/Sr-86 value based on unaltered brachiopod samples from within 0.2 m of either side of the boundary is 0.708231 +/- 0.000021 (NBS 987 = 0.710240). Oxygen isotope values of unaltered brachiopods from the Devonian side of the boundary are -1.99 +/- 2.29% (PDB) and those from the Carboniferous side are -3.08 +/- 0.51% (PDB, p = 0.229), which are from within to outside the range recorded in Recent low-latitude counterparts. Carbon isotope values for the Devonian brachiopods with +4.37 +/- 1.69% (PDB) are dissimilar to those from the Carboniferous side of the boundary with +1.93 +/- 0.49% (PDB; p = 0.0001), but both mostly overlap with the range observed in Recent low-latitude brachiopods. The large positive excursions in delta(13)C (Delta5.5%) and 8180 (Delta6.9%) of the unaltered brachiopods reflect changing oceanographic conditions of the La Serre Sea and possibly of the global oceans during the uppermost Middle and Upper S. praesulcata Subzones. Oxygen isotope trend may reflect, in part, a climatic response of a rapid, short and distinct glacial event during the upper Middle S. praesulcata Subzone. This cryogenic event of a larger oceanographic/climatic shift correlates, in part, to the Hangenberg Event sensu lato. Excursions in the seawater-Sr-87 bracket the onset and offset of the glacial event, reflecting changes in continental weathering patterns and processes and with it changes in riverine fluxes. In contrast, the carbon isotope shift although related to the cooling trend is probably associated with a drawdown of atmospheric CO2 and/or burial of organic matter. The biochemostratigraphic values/contents and trends presented in this study, in conjunction with biostratigraphic observations, facilitate the correlation of sequences at Hasselbachtal and Wocklum (Germany), Nanbiancun (China) and Starks Road and Hannibal (Missouri, USA). (C) 2004 Elsevier B.V All rights reserved. [less ▲]

Detailed reference viewed: 5 (0 ULg)
Full Text
See detailA Review of Agrometeorological Monitoring Tools and Methods Used in the West African Sahel
Traore, Seydou; Sidibe, Brahima; Djaby, Bakary ULg et al

Scientific conference (2004, March 23)

Agrometeorological monitoring in the Sahelian countries consists of collecting, processing, and analyzing various data and information that can affect the outcome of the agricultural season. It combines ... [more ▼]

Agrometeorological monitoring in the Sahelian countries consists of collecting, processing, and analyzing various data and information that can affect the outcome of the agricultural season. It combines observational data from national meteorological, hydrological, agricultural extension, plant protection, and livestock breeding offices, as well as satellite data provided by the AGRHYMET Center. From May until the end of October, multidisciplinary working groups (MWGs) in each country publish dekadal and monthly bulletins. At the regional level in the AGRHYMET Center, data and information coming from the national components are combined with satellite data to elaborate regional syntheses that are published at different time steps. In these publications, the current situation is analyzed and compared with that of the previous period, the previous year, and the average. Forecasts of seasonal rainfall and crop yields, that are refined from month to month, are also given. Color maps illustrates the amounts of rainfall, sowing dates, crop water requirements, satisfaction indices, yield estimates, zones with particular pests, and the advance of the vegetation front. Hard copies and electronic versions of these publications are mailed to subscribers. They are also posted on the Center’s website: www.agrhymet.ne. [less ▲]

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailt-channel unitarity and photon cross sections
Cudell, Jean-René ULg; Martynov, E.; Soyez, G.

in Nuclear Physics B (2004), 682(1-2), 391-420

We analyse the consequences of t-channel unitarity for the photon hadronic cross sections. We show that gamma((*))p and gamma((*))gamma((*)) elastic amplitudes must include the complex-j plane ... [more ▼]

We analyse the consequences of t-channel unitarity for the photon hadronic cross sections. We show that gamma((*))p and gamma((*))gamma((*)) elastic amplitudes must include the complex-j plane singularities associated with hadronic elastic amplitudes, and give the characteristics of possible new singularities. We also show that several different models of hadronic total cross sections can be used to predict the LEP data from the HERA measurements. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 14 (4 ULg)
Full Text
See detailContribution à l'extraction et à la caractérisation des fibres de la pulpe de dattes
Elleuch, M.; Besbes, S.; Blecker, Christophe ULg et al

Conference (2004, March 21)

Detailed reference viewed: 15 (1 ULg)
Full Text
See detailModélisation des impacts des changements climatiques sur les ressources en eaux souterraines
Dassargues, Alain ULg

Scientific conference (2004, March 17)

Detailed reference viewed: 12 (0 ULg)
Full Text
See detailModélisation des impacts des changements climatiques sur les ressources en eaux souterraines
Dassargues, Alain ULg

Scientific conference (2004, March 15)

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailSilica reinforced triblock copolymer gels
Theunissen, E.; Overbergh, N.; Reynaers, H. et al

in Polymer (2004), 45(6), 1857-1865

The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has ... [more ▼]

The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from a viscoclastic rubber to a plastic fluid and from a plastic fluid to a viscoelastic liquid are shifted to more elevated temperatures when silica is added to the triblock copolymer gel. [less ▲]

Detailed reference viewed: 12 (0 ULg)
Full Text
See detailLes mammites en élevage laitier. Outils et stratégies de diagnostic.
Hanzen, Christian ULg

Conference (2004, March 12)

Detailed reference viewed: 54 (7 ULg)