Os | EPFL Graph Search

Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?

Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.

Découvrez-en plus sur les applications Graph.

vignette|250px|Illustration d'un fémur humain extraite de Henry Gray's Anatomy of the Human Body. vignette|250px|La forme des os traduit l'adaptation évolutive aux fonctions qu'ils remplissent pour l'organisme. vignette|250px|Os de pieds déformés par la lèpre. Un os est un organe des Vertébrés, essentiellement constitué d'un tissu conjonctif solidifié qu'on appelle aussi os. Grâce à leur structure, les os sont à la fois légers, souples et solides ; ceux des oiseaux contiennent de l'air et sont particulièrement légers. L'ensemble des os d'un animal constitue son squelette. Chez un nourrisson humain, on dénombre jusqu'à ; chez un adulte, on en compte 206. Dans le règne animal, des évolutions alternatives dans la constitution du squelette par rapport à l'os sont la coquille et l'exosquelette de chitine. Chez certains vertébrés (notamment les tortues), les os qui étaient internes sont devenus externes en se transformant en carapace. Fonctions Les os supportent les structures

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (100)

Publications associées

Chargement

Personnes associées (17)

Personnes associées

Chargement

Unités associées (12)

Afficher plus

Unités associées

Chargement

Concepts associés (231)

Concepts associés

Chargement

Cours associés (38)

Cours associés

Chargement

Séances de cours associées (80)

Séances de cours associées

Chargement

ME-482: Biomechanics of the musculoskeletal system

The basis for a mechanical description of the musculoskeletal system are presented. This description is based on the concepts of solid mechanics, physiology and anatomy of the musculoskeletal system. Concrete examples of the development of implants are also covered.

BIOENG-449: Tissue engineering

Tissue engineering is an interdisciplinary field that broadly impacts human health. This course provides students an overview of how engineering approaches can be used to investigate and manipulate cell and tissue functions and enable students to be on the cutting edge of tissue engineering.

BIO-687: Engineering of musculoskeletal system and rehabilitation

This course presents today research questions and methods associated to the musculoskeletal system, its pathologies, and treatment.

Ostéoporose

L' est caractérisée par une fragilité excessive du squelette, due à une diminution de la masse osseuse et à l'altération de la microarchitecture osseuse. La solidité de l'os résulte en effet d'un éq

Crâne

vignette|right|300px|Crâne en 3D d'un autochtone qui aurait vécu dans la zone de Descalvado au Brésil. Le crâne est une structure osseuse ou cartilagineuse de la tête, caractéristique des crâniates (d

Muscle squelettique

Les muscles squelettiques sont les muscles sous contrôle volontaire du système nerveux central. Le corps humain comprend environ 570 muscles présents chez tous les individus sains. Leur corps conti

Micromotion measurement around femoral stem for the long-term success of total hip arthroplasty

The primary stability of cementless femoral components is crucial for the long-term success of total hip arthroplasty. The mechanisms which influence this stability are not yet well understood. However, mechanical environment in peri-implant tissue is known to be a key parameter in this context. Particularly, implant loading induces local micromotions at the bone-implant interface and affects the stability of the implant. In this project we are interested to characterize these micromotions and to interpret them into clinical solutions. In the first part of the project, we propose to design a loading device which allows to apply loads on bones in-vitro and to generate these micromotions. In the second part, student will use the microCT scan system to take images of bone under different loads and finally a home-made algorithm should be developed for micromotion measurement and statistical analyses. The work uses both biomechanics and image processing principles.

2012

Chargement

A numerical model to reproduce an experimental design to detect strain in cement

Christina Maria Bauer

An experimental set-up consisting of a loading device inserted in a μCT scanner was numerically simulated to predict the strain at the bone-implant interface of the scapula after applying various loading conditions. The aim of the project was to determine which applied force is required to induce strain measurable by the μCT scanner. First, a 3D model of the bone was obtained by scanning a cadaveric scapula using CT scanner. Second, cortical and trabecular bone were segmented according to Hounsfield Units using Amira software. Extracted 3D scapula was assembled with a glenoid implant and cement and was cut to fit into the loading device. Final, a finite element model was created using Abaqus software. A mesh convergence study was undertaken to set the local element size to 2 mm around the peri-implant area. Strain – volume distribution in the cement was investigated. For an axial loading of 2.4 kN, 60% of the volume achieved a maximum principal strain value lying between 0.15% - 0.29% strain. Previous studies on DVC approach showed strain errors of 6 to 8 με. Such a low error percentage would be suitable for this study and hence the strain level should be detectable.

2016

Chargement

T Cell Costimulation Molecules CD80/86 Inhibit Osteoclast Differentiation by Inducing the IDO/Tryptophan Pathway

Zhen Chen, Mario Michael Zaiss

Bone resorption is seminal for the physiological remodeling of bone during life. However, this process needs to be strictly controlled; excessive bone resorption results in pathologic bone loss, osteoporosis, and fracture. We describe a control mechanism of bone resorption by the adaptive immune system. CD80/86, a pair of molecules expressed by antigen-presenting cells and involved in T cell costimulation, act as negative regulator for the generation of bone-resorbing osteoclasts. CD80/86-deficient mice were osteopenic because of increased osteoclast differentiation. CD80/86-deficient osteoclasts escaped physiological inhibition by CTLA-4 or regulatory T cells. Mechanistically, engagement of CD80/86 by CTLA-4 induced activation of the enzyme indoleamine 2,3-dioxygenase (IDO) in osteoclast precursors, which degraded tryptophan and promoted apoptosis. Concordantly, IDO-deficient mice also showed an osteopenic bone phenotype with higher numbers of osteoclast precursors and osteoclasts. Also, IDO-deficient mononuclear cells escaped the anti-osteoclastogenic effect of CTLA-4. This molecular mechanism was also present in humans because targeting CD80/86 by abatacept, a CTLA-4-immunoglobulin fusion protein, reduced, whereas blockade of CTLA-4 by ipilimumab antibody enhanced, the frequency of peripheral osteoclast precursors and osteoclastogenesis. In summary, these data show an important role of the adaptive immune system, in particular T cell CD80/86 costimulation molecules, in the physiological regulation of bone resorption and preservation of bone mass, as well as affect the understanding of the function of current and future drugs fostering or blocking the effects of CTLA-4 in humans.

Amer Assoc Advancement Science2014

Chargement