Characterization of a bone mimicking phantom by means of circumferential guided waves dispersion curves

International audiencePrevious studies have evidenced the circumferential propagation of waves guided by the roughly cylindrical cortical shell of the femoral neck. We hypothesize that measuring the phase velocities of such waves could yield estimates of the cortical thickness and material properties, which could improve fracture risk prediction. The objective of this study is to test the ability of the DORT method, processing based on time reversal principle, to measure circumferential guided waves in a bone-mimicking tube. The tube has the typical dimensions of the mid-femoral neck. A focused array specifically designed for this study was used for emission and reception. To serve as a noise-free reference, the experiment was also simulated based on an analytical formulation. The DORT method was applied to experimentally recorded and simulated data to retrieve the guided waves dispersion curves. Five branches of modes were obtained. They were identified by comparison with the theoretical dispersion curves of a semi-immersed plate. Experimental branches can be used in an inverse scheme to obtain estimations of the shell properties. This study shows that measuring circumferential guided waves is feasible in a structure with dimensions and material properties (elasticity, attenuation) close to those of the cortical compartment of the femoral neck

Targeting of Sna3p to the Endosomal Pathway Depends on Its Interaction with Rsp5p and Multivesicular Body Sorting on Its Ubiquitylation

Rsp5p is an ubiquitin (Ub)-protein ligase of the Nedd4 family that carries WW domains involved in interaction with PPXY-containing proteins. It plays a key role at several stages of intracellular trafficking, such as Ub-mediated internalization of endocytic cargoes and Ub-mediated sorting of membrane proteins to internal vesicles of multivesicular bodies (MVBs), a process that is crucial for their subsequent targeting to the vacuolar lumen. Sna3p is a membrane protein previously described as an Ub-independent MVB cargo, but proteomic studies have since shown it to be an ubiquitylated protein. Sna3p carries a PPXY motif. We observed that this motif mediates its interaction with Rsp5p WW domains. Mutation of either the Sna3p PPXY motif or the Rsp5p WW3 domain or reduction in the amounts of Rsp5 results in the mistargeting of Sna3p to multiple mobile vesicles and prevents its sorting to the endosomal pathway. This sorting defect appears to occur prior to the defect displayed in rsp5 mutants by other MVB cargoes, which are correctly sorted to the endosomal pathway but missorted to the vacuolar membrane instead of the vacuolar lumen. Sna3p is polyubiquitylated on one target lysine, and a mutant Sna3p lacking its target lysine displays defective MVB sorting. Sna3p undergoes Rsp5-dependent polyubiquitylation, with K63-linked Ub chains

Martial et la pens??e de S??n??que

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Pline l'Ancien, Histoire naturelle, livre XI, texte établi, traduit et commenté par A. Ernout et le Dr R. Pépin (Collection des Universités de France), 1947

Grimal Pierre. Pline l'Ancien, Histoire naturelle, livre XI, texte établi, traduit et commenté par A. Ernout et le Dr R. Pépin (Collection des Universités de France), 1947. In: Revue des Études Anciennes. Tome 50, 1948, n°3-4. pp. 389-391

W. Deonna, De Télesphore au « moine bourru ». Dieux, génies et démons encapuchonnés (Collection Latomus, vol. XXI), 1955

Grimal Pierre. W. Deonna, De Télesphore au « moine bourru ». Dieux, génies et démons encapuchonnés (Collection Latomus, vol. XXI), 1955. In: Revue des Études Anciennes. Tome 58, 1956, n°1-2. pp. 107-108

Georg Rohde, Studien und Interpretationen zur antiken Literatur, Religion und Geschichte, 1963

Grimal Pierre. Georg Rohde, Studien und Interpretationen zur antiken Literatur, Religion und Geschichte, 1963. In: Revue des Études Anciennes. Tome 75, 1973, n°1-2. pp. 126-127