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See detailPhysique de l'atmosphère et de l'environnement terrestres
Gérard, Jean-Claude ULg

Learning material (2002)

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See detailPhysique de la haute atmosphère et de l'espace : l'ionosphère terrestre
Warnant, René ULg

Learning material (2005)

Detailed reference viewed: 20 (0 ULg)
See detailPhysique des matériaux : partim 1 métal
Lecomte-Beckers, Jacqueline ULg

Learning material (2008)

Notions sur le cristal métallique parfait : état liquide, gazeux, solide, forces interatomiques, réseaux cristallins. Propriétés des cristaux métalliques parfaits : propriétés physiques, mécaniques ... [more ▼]

Notions sur le cristal métallique parfait : état liquide, gazeux, solide, forces interatomiques, réseaux cristallins. Propriétés des cristaux métalliques parfaits : propriétés physiques, mécaniques (élasticité-plasticité et rupture), thermiques, électriques. Les imperfections dans les réseaux cristallins : défauts ponctuels, dislocations, polycristaux. Les alliages : les solutions solides (thermodynamique - nanostructure - propriétés), les combinaisons intermétalliques (thermodynamique - propriétés). Diagramme de phases. Applications à des alliages de base (acier-aluminium). Les propriétés mécaniques marquantes des métaux limite élastique, domaine élasto-plastique, rupture, fluage, fatigue) : aspects microscopiques. Structures hors d'équilibre : modifications de la microstructure des métaux au cours de la trempe. [less ▲]

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See detailPhysique des matériaux : partim 2 polymères
Lecomte-Beckers, Jacqueline ULg

Learning material (2009)

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See detailLA PHYSIQUE DES RADIATIONS IONISANTES POUR LES NEOPHYTES
LENAERTS, Eric ULg; COUCKE, Philippe ULg

in Revue Médicale de Liège (2014), 69(Supp 1), 13-15

Le développement clinique, à visée diagnostique et thérapeutique, des radiations ionisantes a nécessité une com - préhension de la physique. L’exploitation de ces connaissances a mené à des progrès ... [more ▼]

Le développement clinique, à visée diagnostique et thérapeutique, des radiations ionisantes a nécessité une com - préhension de la physique. L’exploitation de ces connaissances a mené à des progrès majeurs en radiothérapie, visant à l’op - timisation de la distribution de la dose sur la cible et à l’exclu - sion, dans la mesure du possible, de l’irradiation des tissus sains avoisinants. Le développement de nouvelles modalités de traitement, telle l’utilisation des hadrons, est le reflet du développement de cette science. Aux confins de cette radio- physique se trouve la radiobiologie, et l’ensemble des connais - sances dans ces deux domaines permet une optimisation de la prescription médicale [less ▲]

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See detailPhysique Élementaire -- Condensé
Merciadri, Luca ULg

E-print/Working paper (2009)

This document is a kind of Physics formula's form. It is majoritarly coming from a volonty of classifying these last so they are easily accessible. Firstly, this document was redacted in order to be ... [more ▼]

This document is a kind of Physics formula's form. It is majoritarly coming from a volonty of classifying these last so they are easily accessible. Firstly, this document was redacted in order to be prepared to the engineering studies (at ULg). For this reason, the text has not been very developped, so this document is as short (and quick) as possible, with no need to read unnecessary sentences which would slow the reading. Principal sentences have been written, to make links, because Physics is not only formula's: speaking is a very important way to communicate ideas and to link concepts, especially in Sciences. This document is the minimum minimorum that is given in first degree of Computer Sciences at the University of Liège; some notions also come from the Civil Engineers' course (of this same university). Only few proves will be made, to lighten the document; however, formula's will be admitted. Many different notations will be used for the same idea, in order to give the habit of the reader to use different notations (e.g. $U$ or $V$ in $V=RI$). This synthesis is not comprehensive, and does not pretend to be rigourous. Only the essential chapters and sections have been kept. When prerequisites are necessary, they are announced. Indeed, many points are supposed to be known: this document consists only in a set of reminds! It is clear that the reading of this document needs some basical math. knowledge. A summary of the most important notions is ML_SM2009, from the same author. [less ▲]

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See detailPhysisorbed poly(ethylene oxide) is a robust tether for AFM-based single-molecule force spectroscopy
Willet, Nicolas ULg; Lussis, Perrine ULg; Giamblanco, Nicoletta et al

Conference (2014, December 01)

Atomic force microscopy (AFM)-based single-molecule force spectroscopy is a prevalent tool for the exploration of individual (bio)molecules, providing exquisite information on many molecular-level ... [more ▼]

Atomic force microscopy (AFM)-based single-molecule force spectroscopy is a prevalent tool for the exploration of individual (bio)molecules, providing exquisite information on many molecular-level processes. For example, proteins, DNA, polysaccharides, supramolecular polymers and polyelectrolytes have been investigated, revealing details about the strength of intramolecular interactions, folding and unfolding pathways, mechanics, conformational changes, reactivity, kinetics, etc. For each particular system under investigation, the experimental design is a decisive phase that often involves a multistep chemical protocol, including grafting, derivatization, coupling, (de-)protection, and other functionalization reactions. Procedures of sample preparation are often complex and time-consuming. Hence, there is a need for new general platforms allowing for straightforward sample preparation adapted to single-molecule studies, i.e. a tight attachment to both the substrate and the tip, and a low density to favor single-molecule detection. We report here on the use of poly(ethylene oxide) (PEO) as a tether to probe various properties of individual molecules. The polymeric linker acts as a handle that stably binds to the AFM tip. The simple adsorption of poly(ethylene oxide) to the tip is versatile and provides an appropriate system configuration for the investigation of many different biological and synthetic molecular systems. To attest for this versatility and adequacy with advanced single-molecule investigation, we present different examples of PEO-mediated studies about the unfolding of a synthetic peptide, the mechanochemical behavior of a molecular machine and finally the stability of a metallo-supramolecular complexed polymer. All the requirements for the study of peptide conformation, tiny molecular machines or metallo-supramolecular interactions in solution are here fulfilled. More generally, this method based on non-covalent sorption of PEO on an AFM tip, can be implemented in a wide range of solvents, for the study of many intra- or intermolecular phenomena at the single-molecule level over orders of magnitude of force loading rates. Connecting PEO tethers to a very broad variety of (bio)molecules is a facile and versatile route. The commercial availability of many different functional PEOs makes this tethering strategy even more accessible. [less ▲]

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See detailPhytochemical analysis of Tetraclinis articula in relation to its vasorelaxant property.
zidane, Ahlam; Tits, Monique ULg; Angenot, Luc ULg et al

in Journal of Materials and Environmental Science (2014), 5(5), 1368-1375

Tetraclinis articulata (Cupressaceae), a traditional Moroccan herbal drug is used in oriental Morocco to treat diabetes and arterial hypertension. In a previous study we showed that the crude aqueous ... [more ▼]

Tetraclinis articulata (Cupressaceae), a traditional Moroccan herbal drug is used in oriental Morocco to treat diabetes and arterial hypertension. In a previous study we showed that the crude aqueous extract of T. articulata induces endotheliumdependent relaxation ... [less ▲]

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See detailPhytochemical and pharmacological study of roots and leaves of Guiera senegalensis JF Gmel (Combretaceae)
Fiot, Julien; Sanon, Souleymane; Azas, Nadine et al

in Journal of Ethnopharmacology (2006), 106(2), 173-178

The chemical composition of total alkaloids from leaves and roots of Guiera senegalensis was investigated. Three beta-carboline alkaloids were purified: in addition to harman and tetrahydroharman, known ... [more ▼]

The chemical composition of total alkaloids from leaves and roots of Guiera senegalensis was investigated. Three beta-carboline alkaloids were purified: in addition to harman and tetrahydroharman, known in roots and leaves. harmalan (dihydroharman) was isolated for the first time from roots of Guiera senegalensis. Guieranone A, a naphthyl butenone, was also purified from leaves and roots. The in vitro antiplasmodial activity and the cytotoxicity of extracts and pure compounds were evaluated. Each total alkaloid extract and beta-carboline alkaloids presented an interesting antiplasmodial activity associated with a low cytotoxicity. Harmalan was less active than harman and tetrahydroharman. Guieranone A showed a strong antiplasmodial activity associated with a high cytotoxicity toward human monocytes. Its cytotoxicity was performed against two cancer cell lines and normal skin fibroblasts in order to study its anticancer potential: guieranone A presented a strong cytotoxicity against each cell strains. Finally, we evaluated the potent synergistic antimalarial interaction between Guiera senegalensis and two plants commonly associated in traditional remedies: Mitragyna inermis and Pavetta crassipes. Three associations evaluated were additive. A synergistic effect was shown between total alkaloids extracted from leaves of Guiera senegalensis and those of Mitragyna inermis. This result justified the traditional use of the plants in combination to treat malaria. (c) 2006 Elsevier Ireland Ltd. All rights reserved. [less ▲]

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See detailPhytochemical Study of Plants of Interest for Cosmetics in Mayotte
Saive, Matthew ULg; Fauconnier, Marie-Laure ULg; Danflous, Jean-Paul

Poster (2014, December 16)

This study takes place in a bigger project aiming to identify and to make an inventory of the French Pharmacopeia. Its aim is to identify plants or plant families regularly used in traditional cosmetics ... [more ▼]

This study takes place in a bigger project aiming to identify and to make an inventory of the French Pharmacopeia. Its aim is to identify plants or plant families regularly used in traditional cosmetics in Mayotte. In order to give a direction to the research, two technics where used. At first, the plants and their families used in the pharmacopeia of neighboring regions were inventoried using the literature. The resulting inventory was then compared with the flora of the Mahoran territory. The second technique was the realization of a semi-structured survey with people known for their plant-use knowledge in Mayotte. In order to have significant results, the ethnobotanical survey was done following Trotter & Logan’s protocol. (1986) According to that protocol, the gathered data has to be the following: common name, place of harvest, part used and the posology. Moreover the number of informant has to be big enough in order to integrate the data in several indicators such as: The informant agreement ration (IAR), the fidelity level (FL) and use value (UV). The number of informant was determined based on the population density of the different communes of the island. Another critical factor for this study is the correct identification of each sample. To achieve that when a sample was realized, it was taken twice. One for the analysis, the second sample was pressed and dried so as to enter a herbarium for identification. The last important step of this part of the study is the development of fast technics to establish the samples’ physiological activity. These test will give us qualitative information in order the isolate the plants that show a true potential. The targeted activities and tests being: - Anti-tyrosinase activity through an inhibition of tyrosinase test. - Anti-free-radicals activity through the DPPH test. - Anti-inflammatory activity through an inhibition of lipoxygenase an cyclooxygenase test The following steps of the study is the complete analysis of the physiologically active plants extracts in order to identify the active molecules. The end of the study will result in the creation of cosmetics originating from Mayotte’s flora. The way the cosmetics will be developed is thought so as it can be easily and durably done in Mayotte allowing this study to have a positive impact on the development of the island. [less ▲]

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See detailPhytoplancton de la Baie de Calvi et de la côte occidentale corse: synthèse des suivis DCE 2006 - 2009
Goffart, Anne ULg

Scientific conference (2010, April)

La présentation vise à synthétiser les résultats acquis pour l'indicateur Phytoplancton dans le cadre des suivis DCE des eaux côtières corses.

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See detailPhytoplankton Biomass and Production in the River Meuse (Belgium)
Descy, JP; Servais, P; Smitz, J.S. et al

in Water Research (1987), 21(12), 1557-1566

The biomass and production of the phytoplankton in a relatively unpolluted reach of the river Meuse (Belgium) were followed through two years (1983 and 1984).

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See detailPhytoplankton community dynamics during late spring coccolithophore blooms at the continental margin of the Celtic Sea (North East Atlantic, 2006–2008)
Van Oostende, Nicolas; Harlay, Jérôme ULg; Vanelslander, Bart et al

in Progress in Oceanography (2012), 114

We determined the spatial and temporal dynamics of major phytoplankton groups in relation to biogeochemical and physical variables during the late spring coccolithophore blooms (May-June) along and across ... [more ▼]

We determined the spatial and temporal dynamics of major phytoplankton groups in relation to biogeochemical and physical variables during the late spring coccolithophore blooms (May-June) along and across the continental margin of the northern Bay of Biscay (2006-2008). Photosynthetic biomass (Chla) of the dominant plankton groups was determined by CHEMTAX analysis of HPLC pigment signatures. We used uni- and multivariate statistical techniques to identify the main physical and biogeochemical variables underlying the variation in phytoplankton biomass and community structure. Phytoplankton standing stock biomass varied substantially between and during the campaigns (areal Chla (mg Chla m-2) in June 2006: 63.8 ± 26.5, May 2007: 27.9 ± 8.4, and May 2008: 41.3 ± 21.8), reflecting the different prevailing weather, irradiance, and sea surface temperature conditions between the campaigns. Coccolithophores, represented mainly by Emiliania huxleyi, and diatoms were the dominant phytoplankton groups, with a maximal contribution of, respectively, 72% and 89% of the total Chla. Prasinophytes, dinoflagellates, and chrysophytes often co-occurred during coccolithophorid blooms, while diatoms dominated the phytoplankton biomass independently of the abundance of other groups. The location of the stations on the shelf or on the slope side of the continental margin did not influence the biomass and the composition of the phytoplankton community despite significantly stronger water column stratification and lower nutrient concentrations on the shelf. The alternation between diatom and coccolithophorid blooms of similar biomasses, following the mostly diatom-dominated main spring bloom, was partly driven by changes in nutrient stoichiometry (N:P and dSi:N). High concentrations of transparent exopolymer particles (TEP) were associated with stratified, coccolithophore-rich water masses, which probably originated from the slope of the continental margin and warmed during advection onto the shelf. Although we did not determine the proportion of export production attributed to phytoplankton groups, the abundance of coccolithophores, TEP, and coccoliths may affect the carbon export efficiency through increased sinking rates of particles formed by aggregation of TEP and coccoliths. [less ▲]

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See detailThe phytoplankton community of the river Meuse, Belgium: seasonal dynamics (year 1992) and the possible incidence of zooplankton grazing
Gosselain, Véronique ULg; Descy, Jean-Pierre; Everbecq, Etienne ULg

in Hydrobiologia (1994), 289

Qualitative and quantitative aspects of the phytoplankton of the river Meuse were studied during 1992 at a point 537 km from the source. The phytoplankton was dominated by diatoms and green algae. The ... [more ▼]

Qualitative and quantitative aspects of the phytoplankton of the river Meuse were studied during 1992 at a point 537 km from the source. The phytoplankton was dominated by diatoms and green algae. The factors regulating the phytoplankton groxth were clearly physical variables : discharge, temperature and irradiance. [less ▲]

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See detailPhytoplankton control: the role of in situ nutrient recycling?
Darchambeau, François ULg; Thys, Isabelle; Leporcq, Bruno et al

Poster (1999, August 25)

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See detailPhytoplankton ecology of Lake Kivu (eastern Africa): biomass, production and elemental ratios
Sarmento, Hugo; Isumbisho, Mwapu; Stenuite, Stephan et al

in Verhandlungen der Internationalen Vereinigung für Theoretische und Angewandte Limnologie = Proceedings of the International Association of Theoretical and Applied Limnology (2009, January), 30(5), 709-713

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See detailPhytoplankton ecology of Lake Kivu (eastern Africa): biomass, production and elemental ratios
Darchambeau, François ULg; Sarmento, Hugo; Isumbisho, Mwapu et al

Scientific conference (2007, October 01)

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See detailPhytoplankton ecology of Lake Kivu (Eastern Africa): biomass, production and elemental ratios
Sarmento, Hugo; Isumbisho, Mwapu; Stenuite, Stephan et al

Conference (2007, August 16)

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See detailPhytoplankton of Lake Kivu
Sarmento, Hugo; Darchambeau, François ULg; Descy, Jean-Pierre

in Descy, Jean-Pierre; Darchambeau, François; Schmid, Martin (Eds.) Lake Kivu, Limnology and Biogeochemistry of a Tropical Great Lake (2012)

This chapter reviews taxonomic composition, biomass, production and nutrient limitation of the phytoplankton of Lake Kivu. Present Lake Kivu phytoplankton is dominated by cyanobacteria – mainly ... [more ▼]

This chapter reviews taxonomic composition, biomass, production and nutrient limitation of the phytoplankton of Lake Kivu. Present Lake Kivu phytoplankton is dominated by cyanobacteria – mainly Synechococcus spp. and thin filaments of Planktolyngbya limnetica – and by pennate diatoms, among which Nitzschia bacata and Fragilaria danica are dominant. Seasonal shifts occur, with cyanobacteria developing more in the rainy season, and the diatoms in the dry season. Other groups present are cryptophytes, chrysophytes, chlorophytes and dinoflagellates. According to a survey conducted in the period 2002–2008, the composition of the phytoplankton assemblage was quasi homogeneous among lake basins. The mean euphotic depth varied between 17 and 20 m, and the increase in the ratio between mixed layer depth and euphotic depth to about 2 in the dry season may have selected for diatoms and cryptophytes, which tended to present their maximal development in this season, when cyanobacteria slightly decreased. Mean chlorophyll a concentration was 2.16 mg m−3, and the mean daily primary production was 0.62 g C m−2 day−1 (range, 0.14–1.92), i.e. in the same range as in other large oligotrophic East African Rift lakes. Seston elemental ratios indicated a moderate P deficiency during the dry, mixed season and a severe P limitation during part of the rainy, stratified season; the C:N ratio indicated a moderate N limitation throughout the year. Nutrient addition assays pointed to a direct N limitation and co-limitation by P during rainy seasons and P or N limitation during dry seasons depending on the year. Thus, phytoplankton ecology in Lake Kivu does not differ from that of other Rift lakes, where seasonal variations result in a trade-off between low light with high nutrient supply and high light with low nutrient supply. Phytoplankton production in Lake Kivu is also similar to that of other Rift lakes, and nutrient limitation of phytoplankton growth may occur as a result of variable availability of N and P, as in Lakes Tanganyika and Malawi, even though the extent of P limitation seems greater in Lake Kivu. [less ▲]

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