The intra-operative prone position used for the posterior instrumentation of scoliotic patients has been shown to reduce the spinal deformities prior to instrumentation by 37% on average. However, ...the effects of the lateral decubitus position used for anterior approaches and minimally invasive techniques have not been investigated. The objectives were to characterize, model and study the biomechanics of this intra-operative posture. Several clinical indices were measured on the pre- and intra-operative radiographs of six scoliotic patients. A personalized finite element mode (FEM) was developed using the pre-op 3D reconstruction, and a three-step method was developed to simulate the lateral decubitus positioning. Two additional intra-op postures, simulating different pelvic obliquities, were also tested by varying the inclination of L5. The radiographic evaluation of the lateral decubitus position showed a significant reduction of 44% of the major curve with 18 mm of apical vertebra translation. The FEM was able to reproduce the intra-op spine geometry with no significant difference with the measured values. Simulations also showed that the pelvic obliquity had different effects on the lumbar and major Cobb angles depending on the scoliotic curve type. The lateral decubitus posture reduces significantly the scoliotic curvatures prior to instrumentation, which was dependent on the pelvic obliquity.
Le présent ouvrage, pour lequel ont collaboré des chercheurs belges, français et canadiens, aborde dans un premier temps des concepts de développement durable en économie avant de les appliquer, dans ...un second temps, à des problématiques régionales. Les méthodes d’évaluation de la durabilité, l’analyse du cycle de vie ainsi que l’étude du développement soutenable comme un problème d’innovation technique permettent de mieux comprendre et de pouvoir évaluer l’impact de nos actions en termes de soutenabilité. L’implémentation régionale qui s’en suit, qu’elle soit théorique ou empirique, traite, entre autres, de l’impact de la pollution par le bruit des aéroports sur les riverains, d’interactions entre système économique et services écosystémiques pour des nourriceries de poissons, ou de calculs d’indicateurs et de mesures de bien-être sur base de statistiques régionales.
The carbohydrate requirement for alignment and fusion of embryonic quail muscle cells has been examined in tissue culture by use of tunicamycin (TM). The mononucleated, spindle-shaped proliferating ...myoblasts were treated with TM at various times before fusion and differentiation into multinucleated muscle fibers capable of spontaneous contraction. Tm blocked protein glycosylation and expression of glycoproteins on the cell surface, and strongly inhibited fusion when added to cultures of differentiating muscle cells before the fusion "burst," but had no apparent effect on cell alignment. The inhibition of fusion was partially prevented when TM was administered in the presence of protease inhibitors such as leupeptin and pepstatin, but the inhibition of glycosylation was not prevented. Both glycosylation and fusion were completely restored to normal by the removal of the antibiotic from the medium. These studies provide strong support for the idea that myoblast fusion is partially mediated by glycoproteins with asparagine-linked oligosaccharides. However, the requirement for the carbohydrate portion of the glycoprotein appears to be indirect in that it acts to stabilize the protein moiety against proteolytic degradation. Our findings do not rule out the possibility that oligosaccharide units of surface glycolipids have some role in myoblast fusion.
A spectroscopic study of the amino functionalization of double-walled carbon nanotube (DWCNT) is performed. Original experimental investigations by near edge X-ray absorption fine structure ...spectroscopy at the C and O K-edges allow one to follow the efficiency of the chemistry during the different steps of covalent functionalization. Combined with Raman spectroscopy, the characterization gives a direct evidence of the grafting of amino-terminated molecules on the structural defects of the DWCNT external wall, whereas the internal wall does not undergo any change. Structural and mechanical investigation of the amino functionalized DWCNT / epoxy composites show coupling between epoxy molecules and the DWCNTs. Functionalization improves the interface between amino-functionalized DWCNT and the epoxy molecules. The electrical transport measurements indicate a percolating network formed only by inner metallic tubes of the DWCNTs. The activation energy of the barriers between connected metallic tubes is determined around 20 meV.
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