Search results for "structures"
showing 10 items of 4815 documents
Kinematics of the ulna during pronation and supination in a cadaver study: implications for elbow arthroplasty
2003
Objective. Aim of this study was to exactly describe and quantify kinematics of the ulna during pro- and supination. Design. Biomechanical study in fresh frozen cadavers. Background. A previous MRI study revealed a varus/valgus motion of the ulna averaging 7.1° during pro-/supination. Axial rotation, however, could not be quantified. Methods. Sixteen arms were examined in a new apparatus that fixed the humerus on a template and allowed forearm rotation. Motion of a Kirschner wire placed in the ulna was recorded in steps of 30° by two perpendicularly arranged charge coupled device cameras during pro- and supination. Results. From supination to pronation the ulna showed a semi-lunar evasive m…
Aberrant glycosylation of alpha-dystroglycan causes defective binding of laminin in the muscle of chicken muscular dystrophy.
2005
Dystroglycan is a central component of dystrophin-glycoprotein complex that links extracellular matrix and cytoskeleton in skeletal muscle. Although dystrophic chicken is well established as an animal model of human muscular dystrophy, the pathomechanism leading to muscular degeneration remains unknown. We show here that glycosylation and laminin-binding activity of alpha-dystroglycan (alpha-DG) are defective in dystrophic chicken. Extensive glycan structural analysis reveals that Galbeta1-3GalNAc and GalNAc residues are increased while Siaalpha2-3Gal structure is reduced in alpha-DG of dystrophic chicken. These results implicate aberrant glycosylation of alpha-DG in the pathogenesis of mus…
Ritz Solution for Transient Analysis of Variable-Stiffness Shell Structures
2020
The dynamic response of thin-walled structures is driven by mass and stiffness distribution. As such, variable-stiffness (VS) composites offer opportunities to tune structural dynamic responses. To this extent, efficient analysis tools become increasingly important for structural analysis and design purposes. In this work, an efficient and versatile Ritz method for free vibrations and linear transient analysis of VS doubly curved shell structures is presented. VS shell structures are modeled as an assembly of shell-like domains. The shell kinematics is based on the first-order shear deformation theory, and no further assumption is made on the shallowness or on the thinness of the structure.…
Stiffness and Reinforcement Effect of electrical Resistance Strain Gauges
2007
: The increasing use of low-modulus materials, on which the reinforcement effect of the electrical resistance strain gauge is not negligible, has re-opened the research interest into this issue. This study deals with the evaluation of stiffness, and of the strain gauge Young's modulus involved in the estimation of both the global and the local reinforcement effect; the relationship between the strain gauge stiffness and the local reinforcement effect is also analysed. In particular, the experimental technique used to determine the stiffness of some commercial strain gauges is described. The results show that the strain gauge stiffness alone does not permit an accurate evaluation of the loc…
The effects of post-translational processing on dystroglycan synthesis and trafficking1
2003
Dystroglycan is a component of the dystrophin glycoprotein complex that is cleaved into two polypeptides by an unidentified protease. To determine the role of post-translational processing on dystroglycan synthesis and trafficking we expressed the dystroglycan precursor and mutants thereof in a heterologous system. A point mutant in the processing site, S655A, prevented proteolytic cleavage but had no effect upon the surface localisation of dystroglycan. Mutation of two N-linked glycosylation sites that flank the cleavage site inhibited proteolytic processing of the precursor. Furthermore, chemical inhibition of N- and O-linked glycosylation interfered with the processing of the precursor a…
Development of the first marmoset-specific DNA microarray (EUMAMA): a new genetic tool for large-scale expression profiling in a non-human primate
2007
Abstract Background The common marmoset monkey (Callithrix jacchus), a small non-endangered New World primate native to eastern Brazil, is becoming increasingly used as a non-human primate model in biomedical research, drug development and safety assessment. In contrast to the growing interest for the marmoset as an animal model, the molecular tools for genetic analysis are extremely limited. Results Here we report the development of the first marmoset-specific oligonucleotide microarray (EUMAMA) containing probe sets targeting 1541 different marmoset transcripts expressed in hippocampus. These 1541 transcripts represent a wide variety of different functional gene classes. Hybridisation of …
Orbital Decompression for Endocrine Ophthalmopathy: The Endonasal Approach
1994
A surgical endonasal procedure is described to perform orbital decompression in patients suffering from ophthalmopathy in Grave's disease. The decompression technique employs removal of the lamina papyracea as an exclusive modality or in conjunction with a transmaxillary or lateral decompression approach. This present series contain 23 patients who underwent decompression over a 3-year period and were followed for at least 6 months postoperative. The results of decompression were assessed by measuring reduction in proptosis and visual acuity. All patients demonstrated improved visual acuity. Measuring retroplacement of the globe, the endonasal approach proved to equal the results obtained …
Patient-specific computational evaluation of stiffness distribution in ascending thoracic aortic aneurysm
2021
Quantifying local aortic stiffness properties in vivo is acknowledged as essential to assess the severity of an ascending thoracic aortic aneurysm (ATAA). Recently, the LESI (local extensional stiffness identification) methodology has been established to quantify non-invasively local stiffness properties of ATAAs using electrocardiographic-gated computed tomography (ECG-gated CT) scans. The aim of the current study was to determine the most sensitive markers of local ATAA stiffness estimation with the hypothesis that direct measures of local ATAA stiffness could better detect the high-risk patients. A cohort of 30 patients (12 BAV and 18 TAV) referred for aortic size evaluation by ECG-gated…
Celecoxib for recurrent sclerouveitis after syphilitic panuveitis. A case report
2011
Purpose To report a case of recurrent ocular inflammation after optimal therapy of bilateral syphilitic panuveitis responding to oral celecoxib. Methods A case report was conducted. Results A 76-year-old man presented with painful blurry vision in both eyes. Ocular examination disclosed bilateral panuveitis. Serological testing confirmed blood and cerebrospinal fluid syphilitic involvement. After 2 weeks of intravenous penicillin therapy, recurrent episodic sclerouveitis was observed. Conclusion Ocular inflammation after healing of infectious uveitis is a rare ophthalmic sequela. In an immunocompetent patient, either re-infection or immune uveitis should be evoked. Non-steroidal therapeutic…
Explicit behavioral detection of visual changes develops without their implicit neurophysiological detectability
2012
Change blindness is a failure of reporting major changes across consecutive images if separated, e.g., by a brief blank interval. Successful change detection across interrupts requires focal attention to the changes. However, findings of implicit detection of visual changes during change blindness have raised the question of whether the implicit mode is necessary for development of the explicit mode. To this end, we recorded the visual mismatch negativity (vMMN) of the event-related potentials (ERPs) of the brain, an index of implicit pre-attentive visual change detection, in adult humans performing an oddball-variant of change blindness flicker task. Images of 500 ms in duration were prese…