References of "2009"
     in
Bookmark and Share    
See detailAFM-based mechanical testing of electrospun PCL fibers
Croisier, Florence ULg; Duwez, Anne-Sophie ULg; Jérôme, Christine ULg et al

Poster (2009, December 14)

Poly(ε-caprolactone)(PCL forms a part of the aliphatic polyesters; the biodegradable and biocompatible character of these polymers makes them outstanding candidates for short-to medium-term biomedical ... [more ▼]

Poly(ε-caprolactone)(PCL forms a part of the aliphatic polyesters; the biodegradable and biocompatible character of these polymers makes them outstanding candidates for short-to medium-term biomedical applications, especially in the form of nanometric fibers,as their assembly mimics the extracellular matrix structure. However, a prerequisite to their application as nanofibrous biomaterial scaffolds is the investigation of their mechanical strength. In the present study, PCL fibers produced by electrospinning were individually tested using an AFM-based nano-scale three-point bending technique. [less ▲]

Detailed reference viewed: 97 (17 ULg)
See detailSummary of aim and achievements in Work Package 7 "Functional Coatings"
Jérôme, Christine ULg

Conference (2009, December 14)

Detailed reference viewed: 11 (3 ULg)
See detailMicrobial diversity and activity in temperate forest and grassland ecosystems
Malchair, Sandrine ULg

Doctoral thesis (2009)

Ecosystems currently face widespread biodiversity losses and other environmental disturbances, such as climate warming, related to increased anthropogenic activities. Within this context, scientists ... [more ▼]

Ecosystems currently face widespread biodiversity losses and other environmental disturbances, such as climate warming, related to increased anthropogenic activities. Within this context, scientists consider the effects of such changes on the biodiversity, and hence on the activity, of soil microorganisms. Indeed, soil microorganisms mediate a wide range of soil processes. Currently, knowledge on soil microbial diversity is still limited, partially due to technical limitations. The advent of molecular-based analyses now allows studying the soil microbial diversity. These advances in the study of soil microbial communities have lead to a growing evidence of the critical role played by the microbial community in ecosystem functioning. This relationship is supposed to be relevant for narrow processes, regulated by a restricted group of microorganisms, such as the nitrification process. This PhD thesis aimed at studying ammonia oxidizing bacteria (AOB) community structure and richness as an integrated part of soil functioning. This research aimed at investigating the effect of aboveground plant diversity on ammonia oxidizing bacteria diversity and function in forest and grassland soils with focus on the influence of (a) functional group identity of grassland plants (legumes, grasses, forbs), (b) grassland plant species richness and (c) tree species, on AOB diversity and function. Another objective of this research was to study the effect of a 3°C increase in air temperature on AOB diversity and function. The link between AOB diversity and function (potential nitrification) is also investigated. For grassland ecosystems, a microcosm experiment was realized. An experimental platform containing 288 assembled grassland communities was established in Wilrijk (Belgium). Grassland species were grown in 12 sunlit, climate controlled chambers. Each chamber contained 24 communities of variable species richness (S) (9 S=1, 9 S=3 and 6 S=9).The grassland species belonged to three functional groups: three species of each grasses (Dactylis glomerata L., Festuca arundinacea SCHREB., Lolium perenne L.), forbs (non-N-fixing dicots; Bellis perennis L., Rumex acetosa L., Plantagolanceolata L.), and legumes (N-fixing dicots; Trifolium repens L., Medicago sativa L., Lotus corniculatus L.). Half of these chambers were exposed to ambient temperature and the other half were exposed to (ambient +3°C) temperature. One ambient and one (ambient+3°C) chambers were destructively harvested 4, 16 and 28 months after the start of the experiment. The influence of plant functional group identity on the nitrification process and on AOB community structure and richness (AOB diversity) was assessed in soils collected from the first two destructive amplings (chapter 2). The effect of plant species richness on AOB diversity and function was considered for soils sampled after 16 and 28 months (chapter 3). AOB function was determined by potential nitrification. AOB community structure and richness were assessed by polymerase chain reaction followed by denaturing gradient gel electrophoresis (DGGE) and sequencing of excised DGGE bands. I found that functional group identity can affect AOB community structure. In particular, the presence of legumes, both in monoculture or in mixture with forbs and grasses, lead to AOB community composition changes towards AOB clusters tolerating higher ammonium concentrations. This change in AOB community structure was only linked to increased potential nitrification under monocultures of legumes, when ammonium was supposed to be not limiting. This study revealed that physiological attributes of AOB and resource availability may be important factors in controlling the nitrification process. This research showed that the impact of plant species richness on the nitrification process could be mediated by the interactions between plants and AOB, through competition for substrate. A 3°C increase in air temperature did not affect AOB community structure, richness or function. In forest ecosystems, we studied the effect of tree species in forest sites located in Belgian and in the Grand-Duchy of Luxembourg covered each by several deciduous or coniferous tree species (Fagus sylvatica L., Quercus petraea (Mattuschka) Lieblein, Picea abies (L.) Karst, Pseudotsuga menziesii (Mirbel) Franco). We investigated the influence of these tree species on microbial processes (chapter 5) related to C and N cycling, particularly with emphasize on the nitrification process and on the diversity of AOB (chapter 6). The results showed that the effect of tree species on net N mineralization was likely to be mediated through their effect on soil microbial biomass, reflecting their influence on organic matter content and carbon availability. Influence of tree species on nitrification (potential and relative) might be related to the presence of ground vegetation through its influence on soil ammonium and labile C availability. AOB community structure was more site-specific than tree specific. However, within sites, AOB community structure under broadleaved trees differed from the one under coniferous trees. The effect on tree species on AOB was likely to be driven by the influence of tree species on net N mineralization, which regulates the substrate availability for AOB. The results also demonstrated that the relationship between AOB diversity and function might be related both to AOB abundance and AOB community structure and richness. This thesis showed no clear relationship between AOB community structure or richness and AOB function. However, we revealed that aboveground grassland plant richness, grassland plant functional groups and tree species influence AOB community structure and richness. [less ▲]

Detailed reference viewed: 65 (3 ULg)
Full Text
See detailResistencia desquiciada en El ejército iluminado de David Toscana
Vanden Berghe, Kristine ULg

Conference (2009, December 13)

Detailed reference viewed: 29 (4 ULg)
See detailVoltaire et l’Optimisme. Candide aujourd’hui
Tilkin, Françoise ULg

Conference given outside the academic context (2009)

Detailed reference viewed: 22 (2 ULg)
Full Text
Peer Reviewed
See detailLiposomes loaded with diglyceride esters of methotrexate and melphalan: studies on stability and hemocompatibility
Kuznetsova, N; Kandyba, A; Bovin, N et al

in Proceedings of the International Liposome Society 2009 Meeting (2009, December 12)

Detailed reference viewed: 12 (0 ULg)
Full Text
Peer Reviewed
See detailTree based ensemble models regularization by convex optimization
Cornélusse, Bertrand ULg; Geurts, Pierre ULg; Wehenkel, Louis ULg

Conference (2009, December 12)

Tree based ensemble methods can be seen as a way to learn a kernel from a sample of input-output pairs. This paper proposes a regularization framework to incorporate non-standard information not used in ... [more ▼]

Tree based ensemble methods can be seen as a way to learn a kernel from a sample of input-output pairs. This paper proposes a regularization framework to incorporate non-standard information not used in the kernel learning algorithm, so as to take advantage of incomplete information about output values and/or of some prior information about the problem at hand. To this end a generic convex optimization problem is formulated which is first customized into a manifold regularization approach for semi-supervised learning, then as a way to exploit censored output values, and finally as a generic way to exploit prior information about the problem. [less ▲]

Detailed reference viewed: 121 (36 ULg)
Full Text
See detailNADH pathway and H2 production in Chlamydomonas reinhardtii
Lecler, Renaud ULg

Scientific conference (2009, December 12)

Detailed reference viewed: 10 (5 ULg)
Full Text
See detailCyanobacterial 
molecular 
diversity 
and distribution 
in 
microbial 
mats from 
antarctic 
lakes
De Carvalho Maalouf, Pedro ULg; Lambion, Alexandre ULg; Zakhia, Frédéric et al

Poster (2009, December 11)

The coastal deglaciated areas of Antarctica hold lakes and other water bodies with a wide spectrum of limnological conditions. Aquatic habitats offer milder conditions to the microorganisms, which are the ... [more ▼]

The coastal deglaciated areas of Antarctica hold lakes and other water bodies with a wide spectrum of limnological conditions. Aquatic habitats offer milder conditions to the microorganisms, which are the only permanent inhabitants of this glacial desert. Among them, cyanobacteria are the first photosynthetic colonisers, sometimes forming thick, cohesive and pigmented benthic mats. In the frame of the BELSPO AMBIO project (Antarctic Microbial BIOdiversity, influence of geographical and ecological factors, www.ambio.ulg.ac.be), we have obtained benthic mat samples coming from lakes from various coastal regions of the continent (MERLIN 2007 and BELARE 2007 field campaigns and by collaborations). We have investigated cyanobacterial molecular diversity via Polymerase Chain Reaction and Denaturating Gradient Gel Electrophoresis (PCR-DGGE) on a set of 80 samples. We couple the numerical analysis of the obtained band patterns with the phylogenetic analysis of the sequences, and by using multivariate analysis, we will assess the role of the ecological and geographical factors shaping the distribution and the diversity of cyanobacteria. Preliminary results of the analysis of 13 samples seem to indicate that lakes separated by a small distance have different cyanobacterial communities, highlighting the importance of ecological factors. Fifty per cent of the obtained Operational Taxonomic Units (OTUs) are potentially endemic to Antarctica while others seem to have a global distribution. The completed study will give us a wide scale view on the distribution and the diversity of cyanobacteria in two biogeographical zones: Continental Antarctica and Maritime Antarctica. Finally, our studies will supply new data and arguments for the ongoing “everything is everywhere, but the environment selects” debate concerning microbial biogeography. [less ▲]

Detailed reference viewed: 106 (5 ULg)
See detailSaisies conservatoires et voies d'exécution: principes généraux
Berthe, Aude ULg

in Actualités en droit de l'exécution forcée (2009)

Detailed reference viewed: 92 (8 ULg)
Full Text
See detailLa saisie immobilière: chronique quinquennale
Georges, Frédéric ULg

in Actualités en droit de l'excécution forcée (2009)

Detailed reference viewed: 51 (16 ULg)
Peer Reviewed
See detailComparative study of Murid gammaherpesvirus 4 infection in mice and in its natural host, the bank voles.
François, Sylvie ULg; Vidick, Sarah ULg; Koteja, Pawel et al

Poster (2009, December 11)

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections ... [more ▼]

Gammaherpesviruses are the archetypes of persistent viruses that have been identified in a range of animals from mice to man. They are host-range specific and establish persistent, productive infections of immunocompetent hosts. Thus, infected individuals simultaneously both elicit antiviral protective immune response and secrete infectious virions. The best studied gammaherpesviruses are Human herpesvirus 4 and Human herpesvirus 8. As these viruses have no well-established in vivo infection model, related animal gammaherpesviruses are an important source of information. We are studying Murid herpesvirus 4 (MuHV-4), a virus that has originally been isolated from bank voles (Myodes glareolus). Although MuHV-4 has not been isolated from house mice (Mus musculus), infection of inbred laboratory mouse strains is commonly accepted as a good model for studying gammaherpesviruses in vivo. It has however never been possible to monitor viral reexcretion and virus transmission in this species suggesting that this model could be imperfect. In this study, we therefore characterized MuHV-4 infection in its natural host, the bank voles, through classical virological methods but also through global luciferase imaging for an anatomical complete view of the infection. Results obtained show that, after intra-nasal infection, the natural route of infection is similar in mice and voles. Following nasal productive infection, the virus spreads to the lung where the infection is accompanied by massive cellular infiltrates. By opposition to extensive viral replication observed in mice, the different analyses indicated that the viral replication was ~1000 fold lower in bank voles. This lower replication did however not affect colonization of latency sites in superficial cervical lymph nodes and spleen as measured by real-time PCR quantification of viral genomes in these organs. In conclusion, this study revealed that MuHV-4 can experimentally infect bank voles, the supposed natural host, but with a lower replicative power. As, gammaherpesvirus epidemiology indicates that transmission correlates with the latent load, our results suggest that gammaherpesviruses may have evolved to infect their hosts without extensive lytic spread. In the future, establishment of experimental transmission in a population of Myodes glareolus should help us to better understand mechanisms used by gammaherpesviruses to evade immune response. [less ▲]

Detailed reference viewed: 12 (5 ULg)
Full Text
See detailApproche laparoscopique en chirurgie abdominale
Detry, Olivier ULg

Scientific conference (2009, December 11)

Detailed reference viewed: 39 (9 ULg)
See detailApplication of molecular techniques to monitor the evolution of bacterial consortia composed of Clostridium sp. in a hydrogen producing bioreactor
Calusinska, Magdalena ULg; Savichtcheva, Olga; Joris, Bernard ULg et al

Poster (2009, December 11)

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean ... [more ▼]

Our current dependence on fossil fuels as the primary energy source contributes to global climate change, environmental degradation and health problems. Hydrogen offers a tremendous potential as a clean, renewable energy currency and it is compatible with electrochemical and combustion processes for energy conversion without producing carbon – based emissions. Many microorganisms, especially photosynthetic as well as facultative and anaerobic bacteria have been reported to produce large amounts of hydrogen from soluble and insoluble biomass. Clostridia, being obligate anaerobes, are capable of biogas production during ‘dark fermentation’ of a wide range of carbohydrates. In this ARC project, entitled Micro – H2 we have focused on a new direction in bio – hydrogen production systems which is the use of mixed cultures of microorganisms (consortia). We expect that the combination of complementary metabolisms could significantly increase the efficiencies of mixed systems compared to monocultures. However, a few fundamental studies need to be carried out in order to investigate and improve the stability of microbial populations involved in the processes. It is now recognised that molecular microbial ecology tools provide the scientific basis to monitor the processes used in environmental biotechnology. To characterize the diversity of bacterial communities, quantitative techniques such as Real – Time Quantitative PCR and FISH (Fluorescence in situ hybridization) and semi – quantitative DGGE (Denaturing Gradient Gel Electrophoresis) have been optimized and applied on different bioreactor samples. This approach enabled for the temporal monitoring of the evolution of bacterial consortia, both in terms of species dominance and their metabolic activity. Molecular analysis of bacterial consortia allowed for careful examination of interactions between different bacterial species within a consortium, which is crucial in the stabilization of the hydrogen production process. [less ▲]

Detailed reference viewed: 38 (4 ULg)