34 resultados para Nullité - immunité - organisation internationale - état étranger


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The adoption of agile software development methodologies may appear to be a rather straightforward process yielding instantly improved software in less time and increasingly satisfied customers. This paper will show that such a notion is a misunderstanding and can be harmful to small software development organisations. A more reasonable approach involves a careful risk assessment and framework for introducing agile practices to address specific risks. A case study with a small software development organisation is provided to show the assessment in practice and the resulting risk mitigation strategies for process improvement.

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In order to broaden the information about the organisation of the nervous system in taxon Acoela, an immunocytochemical study of an undetermined Acoela from Cape Kartesh, Faerlea glomerata, Avagina incola and Paraphanostoma crassum has been performed. Antibodies to 5-HT and the native flatworm neuropeptide GYIRFamide were used. As in earlier studies, the pattern of 5-HT immunoreactivity revealed an anterior structure composed mainly of commissures, a so-called commissural brain. Three types of brain shapes were observed. No regular orthogon was visualised. GYIRFamide immunoreactive cell clusters were observed peripherally to the 5-HT immunoreactive commissural brain. Staining with anti-GYIRFamide revealed more nerve processes than did staining with anti-FMRFamide. As no synapomorphies were found in the organisation of the nervous system of the Acoela and that of the Platyhelminthes, the results support the view that the Acoela is not a member of the Platyhelminthes. (C) 2001 Harcourt Publishers Ltd.

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Objectives The Tat peptide has been widely used for the intracellular delivery of macromolecules. The aim of this study was to modify the peptide to enable regulation of cellular uptake through a dependency on activation by proteases present in the local environment.

Methods The native Tat peptide sequence was altered to inhibit the initial interaction of the peptide with the cell membrane through the addition of the consensus sequence for urokinase plasminogen activator (uPA). uPA expression was characterised and semi-quantitatively rated in three cell lines (U251mg, MDA-MB-231 and HeLa). The modified peptide was incubated with both recombinant enzyme and with cells varying in uPA activity. Cellular uptake of the modified Tat peptide line was compared with that of the native peptide and rated according to uPA activity measured in each cell line.

Key findings uPA activity was observed to be high in U251mg and MDA-MB-231 and low in HeLa. In MDA-MB-231 and HeLa, uptake of the modified peptide correlated with the level of uPA expression detected (93 and 52%, respectively). In U251mg, however, the uptake of the modified peptide was much less (19% observed reduction) than the native peptide despite a high level of uPA activity detected.

Conclusions Proteolytic activation represents an interesting strategy for the targeted delivery of macromolecules using peptide-based carriers and holds significant potential for further exploitation.