Helicopter Noise Reduction By Actively Controlled Flaps

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76305/1/AIAA-2005-2904-610.pd

Filmer le champ social

Daniel Friedmann, chargé de recherche au CNRS Le projet du séminaire partait d’une analyse des réalisations filmiques produisant des documents de recherche. Celles-ci peuvent être référées aux documents de recherche traditionnels mis en œuvre par les sciences humaines sous forme de textes écrits (articles, rapports de recherches, livres, etc.). Nous avons tout d’abord établi une typologie des diverses catégories de documents filmés et/ou de films documentaires distribuées selon l’objet filmé,..

Filmer le champ social

Daniel Friedmann, chargé de recherche au CNRS Le séminaire est parti d’un questionnement sur le statut ambivalent du film documentaire sociologique, entre culture savante et populaire. Essentiellement, ce statut renvoie au rôle de l’image dans le cinéma, à l’illusion-cinématographique qui tend à faire apparaître le fait social comme image animée sans le référer à son extériorité. Le film, plus que tout autre médium (paroles, textes) du fait qu’il produit l’apparence de la chose vivante et a l..

Three-Dimensional Gradients of Cytokine Signaling between T Cells

Immune responses are regulated by diffusible mediators, the cytokines, which act at sub-nanomolar concentrations. The spatial range of cytokine communication is a crucial, yet poorly understood, functional property. Both containment of cytokine action in narrow junctions between immune cells (immunological synapses) and global signaling throughout entire lymph nodes have been proposed, but the conditions under which they might occur are not clear. Here we analyze spatially three-dimensional reaction-diffusion models for the dynamics of cytokine signaling at two successive scales: in immunological synapses and in dense multicellular environments. For realistic parameter values, we observe local spatial gradients, with the cytokine concentration around secreting cells decaying sharply across only a few cell diameters. Focusing on the well-characterized T-cell cytokine interleukin-2, we show how cytokine secretion and competitive uptake determine this signaling range. Uptake is shaped locally by the geometry of the immunological synapse. However, even for narrow synapses, which favor intrasynaptic cytokine consumption, escape fluxes into the extrasynaptic space are expected to be substantial (≥20% of secretion). Hence paracrine signaling will generally extend beyond the synapse but can be limited to cellular microenvironments through uptake by target cells or strong competitors, such as regulatory T cells. By contrast, long-range cytokine signaling requires a high density of cytokine producers or weak consumption (e.g., by sparsely distributed target cells). Thus in a physiological setting, cytokine gradients between cells, and not bulk-phase concentrations, are crucial for cell-to-cell communication, emphasizing the need for spatially resolved data on cytokine signaling

Calcium Hydroxylapatite-Induced Inflammatory Facial Edema and Induration Due to Hashimoto\u27s Thyroiditis

We describe a patient who experienced a diffuse, treatment-refractory facial inflammatory reaction following the injection of calcium hydroxylapatite with lidocaine. The reaction was attributed to undiagnosed Hashimoto\u27s thyroiditis. Exogenous thyroid hormone replacement therapy rapidly resolved the facial inflammation associated with this type of autoimmune hypothyroidism