775 research outputs found

    Receptor-mediated transport of IgG

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    The intestinal epithelium of the neonatal rat is a model system for the study of receptor-mediated endocytosis in which large amounts of IgG are transferred intact across polarized cells. This review summarizes the ultrastructural pathway followed by IgG during cellular transit and several important properties of the membrane receptor that recognizes the IgG

    Gestion durable du paysage : les leçons que les nouveaux parcs naturels régionaux doivent tirer de l'expérience des anciennes corporations

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    The landscape is increasingly perceived as a resource. For this reason, it is necessary to find legal, political and economic instruments that will succeed in managing this “resource landscape” in the long term. The Swiss government recently introduced the instrument of regional nature parks into the legislation governing nature and landscape preservation; the proposed parks are organized on the basis of the French model. The examination of the new parks from the perspective of much older management structures, i.e. the civic municipalities (bourgeoisies) and corporations, makes it possible to demonstrate the strengths and weaknesses of each of these instruments in their contribution to the resolution of use rivalries between actors who use or influence the resource landscape. This comparison also enables the formulation of practical recommendations regarding the management of this resource

    pH-dependent binding of immunoglobulins to intestinal cells of the neonatal rat.

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    Dendritic flux penetration in Pb films with a periodic array of antidots

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    We explore the flux-jump regime in type-II Pb thin films with a periodic array of antidots by means of magneto-optical measurements. A direct visualization of the magnetic flux distribution allows to identify a rich morphology of flux penetration patterns. We determine the phase boundary H(T)H^*(T) between dendritic penetration at low temperatures and a smooth flux invasion at high temperatures and fields. For the whole range of fields and temperatures studied, guided vortex motion along the principal axes of the square pinning array is clearly observed. In particular, the branching process of the dendrite expansion is fully governed by the underlying pinning topology. A comparative study between macroscopic techniques and direct local visualization shed light onto the puzzling TT- and HH-independent magnetic response observed at low temperatures and fields. Finally, we find that the distribution of avalanche sizes at low temperatures can be described by a power law with exponent τ0.9(1)\tau \sim 0.9(1)
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