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1	Damage and failure in the carotid artery: a mechanistic approach Priddy, Lauren Beatty 07 August 2010 (has links) Blunt carotid artery injury (BCAI), resulting primarily from automobile accidents, is a major contributor to the high mortality and morbidity rates associated with carotid artery dissection. More work is needed to characterize carotid artery injury mechanisms, quantify stages of damage, and elucidate failure modalities as a result of this type of injury. The present study examines the structure and mechanics of the carotid artery in the circumferential and axial directions by employing uniaxial tensile testing, high speed videography, interruption testing, scanning electron microscopy (SEM), histological analysis, real-time environmental SEM assessment, and atomic force microscopy (AFM). Results are as follows: (i) the carotid artery exhibits anisotropic, viscoelastic behavior; (ii) intimal failure precedes ultimate tissue failure, and the layers in order of increasing strength are intima, adventitia, and media; (iii) tissue damage accumulates as strain level increases, and failure occurs as a result of void nucleation, void growth, and void coalescence. vessel failure damage mechanics blunt injury arterial dissection carotid artery
2	force d’adhesion des plaques atherosclerotique et son role dans le detachement des plaques / atherosclerotic plaque adhesion strength and its role in plaque rupture Merei, Bilal 29 September 2016 (has links) La rupture de plaque athérosclérotique est une complication grave, menant à des conséquences mortelles. En raison de la complexité du processus, les mécanismes de rupture de la plaque sont encore mal connus. Dans cette thèse, l'approche technique innovante pour mesurer la force d'adhérence développée précédemment sera appliquée à des souris. Elle comprend un protocole de délamination à petite échelle pour mesurer la résistance adhésive des plaques d'athérosclérose. Notre équipe à USC a été la première à effectuer ce type de mesures sur des souris. Une autre innovation de notre travail impliquera l'application d'un modèle de zone cohésive pour décrire le comportement de délamination des plaques athérosclérotiques dans une gamme de conditions physiologiques et physiopathologiques, en utilisant un modèle numérique 2D. Bien que l'approche de la zone cohésive ait été largement utilisée pour modéliser la mécanique des fractures, elle a rarement été appliquée pour décrire la rupture des plaques athérosclérotiques. L'étude de la délamination des plaques (Leng.2015) a été conçue pour tester l'utilisation de zones cohésives en mettant en œuvre une loi de séparation de traction spécifique, en supposant les valeurs des paramètres des lois de comportement de la plaque et de la zone cohésive en utilisant des valeurs de la littérature. L'innovation dans notre approche est d'utiliser une simple loi de séparation de la traction pour étudier le comportement des plaques et identifier leurs propriétés. Des résultats expérimentaux de délamination des plaques ont été utilisés dans la définition des lois de traction-séparation de la zone cohésive. / Atherosclerosis is the underlying cause of many cardiovascular diseases. Plaque rupture is a serious complication of advanced atherosclerosis, leading to life-threatening consequences. The mechanisms of atherosclerotic plaque progression and formation have been widely studied. However, due to the complexity of the process, plaque rupture mechanisms are still poorly understood. In this thesis, the innovative technical approach to measure the adhesive strength developed previously, will be applied to mice. It includes a micro-scale peel experiment protocol to measure adhesive strength of mouse atherosclerotic plaques during delamination from the underlying vessel wall. Our team at USC was the first to perform these types of measurements on mice. Another innovation of our work will involve application of a cohesive zone model to describe delamination behavior of atherosclerotic plaques under a range of physiological and pathophysiological conditions, using a 2D numerical model. While the cohesive zone approach has been widely used to model fracture mechanics, it was rarely applied to describe failure of atherosclerotic plaques. The study of plaque delamination (Leng.2015) was designed to test the use of cohesive zones by implementing a specific traction separation law, assuming the parameter values of the behavior laws of the plaque and the cohesive zone using values from the literature. Innovation in our approach is to use a simple traction separation law to study the behavior of plaques and identifying their properties. Experimental results of delamination of the plaques were used in the definition of traction-separation laws of the cohesive zone. Maladies cardiovasculaires Disssection artérielle Plaque Arthérosclérotique Modes de délamination Mécanique de rupture Modèle à zone cohésive Méthode inverse Cardiovascular diseases Arterial dissection Atherosclerotic plaque Delamination mode Fracture mechanics Cohesive zone model Inverse method
3	Finns det evidens för att höghastighetsmanipulation av nacken kan orsaka stroke? / Is there evidence that high velocity manipulation of the cervical spine can cause stroke? Eriksson, Andreas January 2020 (has links) Höghastighetsmanipulation av nacken är en manuell behandlingsteknik mot smärta i framförallt nacken och skuldrorna. Tekniken har enligt flera källor visats hänga samman med risken för att drabbas av skador på de kärl som försörjer hjärnan med blod, med bland annat stroke som följd. Andra källor har å andra sidan visat att de är en teknik som är säker att utföra. Den här litteraturstudien har sammanställt och utvärderat forskning som på olika sätt söker utreda om det påstådda sambandet är kausalt eller inte. Metoden som valdes var att genom en av SBU färdigställd mall värdera forskningsartiklar och sedan sortera dem efter relevans, för att på så sätt avgöra huruvida sambandet kan ses som kausalt eller inte. Studieresultatet visade att frågan är för komplex för att kunna besvaras i en enskild studie, och att mer forskning behövs inom flera delområden innan frågan kan besvaras fullt ut. Orsaken till detta är att det finns flera orsaksmekanismer, och flera riskgrupper, för denna typ av skada, där flera ännu är okända. Detta gör att en fullständig kartläggning av samband i frågan ännu inte är möjlig. Däremot är det sannolikt att tekniken kan verka som en utlösande faktor, en trigger, hos vissa personer i riskgrupperna. Därför kan det sägas finnas en risk med tekniken rent praktiskt, oavsett om ett kausalt samband mellan tekniken och stroke i sig existerar eller inte. / High Velocity Manipulation of the cervical spine is a manual treatment technique against pain in foremost the neck, shoulders. The technique has according to multiple sources been connected to the risk of injury to the blood vessels that supply the brain with blood, with among others stroke as a consequence. Other sources have on the other hand shown it the technique to be safe to perform. This literature study has compiled and evaluated research that in various ways tries to find out if said connection is causal The method used was to evaluate articles through a pre-made form from SBU, and then to sort them according to relevance to see if the connection is causal or not. The result showed that the question is too complex to be answered in a single study, and that more research is needed to answer the question in full. This is due to the fact that there are multiple mechanisms behinds this form om injury, that the risk seems to exists in certain groups, and that some of these are not yet identifiable. On the other hand there is a high probability that the technique might act as an activating factor in these groups. Because of this there can be said that a risk exists with the technique in practice, no matter if there is a casual connection between the technique and stroke in itself or not. Chiropraktor physioterapeut manipulation stroke vertebral artery carotid artery cervical spinal manipulation therapy SMT High Velocity Low Amplitude Manipulation HVLA Orthopedic Manual Therapy OMT cerebrovascular dissection CVD vertebral arterial dissection VAD CAD CeAD cerebrovascular insult CVI vertebrobasilar disorder VBI ICD9 ICD 10 M430 M435 stroke complications risk Kiropraktor sjukgymnast fysioterapeut naprapat manipulation stroke SMT OMT VAD CAD CeAD cerebrovaskulär insult CVI VBI ICD9 ICD 10 M430 M435 stroke risk Physiotherapy Sjukgymnastik

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