Download or read book Experimental Investigation of Arteries Mechanical Properties written by Ofry Efraim Yossef and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cardiovascular diseases such as aneurisms, atherosclerosis, arterial dissection and hypertension are a leading cause for mortality in the western world. Therefore, understanding and characterization of the mechanical behavior of the arterial wall is of high importance.The mechanical response is a combined passive and active response due to the contraction of smooth muscle cells (SMCs) in the arterial wall. The passive response is attributed to the collagen fibers and elastin fibrils. For a mechanical model that describes arteries properly,both passive and active responses must be investigated. Experiments to investigate biological tissues are complex and therefore a reliable, accurate system and well defined experimental protocol are needed. Furthermore, due to the large variations between test samples, a series of experiments is required for statistically relevant data. A common assumption in the biomechanical community is that arteries are incompressible under physiological conditions. This assumption is due to the high content of water in the artery wall, which is considered incompressible. An experimental-based determination of the level of compressibility is therefore of biomechanical interest, but not easily determined because of difficulties to accurately measure very small differences in volume under a physiological pressure.Therefore, the goals of this M.Sc thesis were a) to provide an experimental-based answer to the level of compressibility of arteries, b) to expand the capabilities of an experimental system, improve its reliability and operational options, c) to perform a large number of experiments on arteries in order to create a database for the determination of material parameters. Experimental evidence on the compressibility of arteries under normal physiological pressure range is provided using a precise experimental apparatus. Nineteen experiments on porcine common carotid were performed by two students and the results were analyzed by the author with the conclusion that: in the physiological pressure range (50to 200 mmHg), a relative volume change of 0.2-5% was obtained, lower compared to the sapheneous and femoral arteries (2-6% ). Most of the arteries had a relative volume change of 0.2-1.5%. Details are given in Chapter 2 which is based on a paper published in JMBBM. An apparatus used to investigate the passive and active response of arteries was enhanced.The pressure was oscillating, unstable and not controlled, the control program was not reliable, the system had only manual operation abilities and diameter was unknown during tests. These limitations were removed. The enhanced apparatus is described in detail in Chapter 3 along with numerous experiments which prove its proper functionality. Experiments for the investigation of the passive response of human left internal mammaryartery (LIMA) (one Radial) using the improved apparatus were made which demonstrate that a typical axial in-vivo stretch ratio for human LIMA is 1.1-1.15. A series of experiments attempting to activate the smooth muscle cells (SMC's) were performed. Since the obtained human arteries provided were soaked in a vasodilator (papaverine) during surgeries, the SMC response was disabled despite "washing" them in physiological solution.Due to the inability to receive un-soaked human arteries, porcine arteries were investigated. A series of seven experiments for the investigation of the active response in porcine arteries were performed showing a maximum change of 17-27% in the diameter at 80 mmHg. The results and conclusions from those experiments and experiments on human arteries for passive response are presented in Chapter 3" -- abstract.

Download or read book Experimental Investigation of Arteries Mechanical Properties written by Ofry Efraim Yossef and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cardiovascular diseases such as aneurisms, atherosclerosis, arterial dissection and hypertension are a leading cause for mortality in the western world. Therefore, understanding and characterization of the mechanical behavior of the arterial wall is of high importance.The mechanical response is a combined passive and active response due to the contraction of smooth muscle cells (SMCs) in the arterial wall. The passive response is attributed to the collagen fibers and elastin fibrils. For a mechanical model that describes arteries properly,both passive and active responses must be investigated. Experiments to investigate biological tissues are complex and therefore a reliable, accurate system and well defined experimental protocol are needed. Furthermore, due to the large variations between test samples, a series of experiments is required for statistically relevant data. A common assumption in the biomechanical community is that arteries are incompressible under physiological conditions. This assumption is due to the high content of water in the artery wall, which is considered incompressible. An experimental-based determination of the level of compressibility is therefore of biomechanical interest, but not easily determined because of difficulties to accurately measure very small differences in volume under a physiological pressure.Therefore, the goals of this M.Sc thesis were a) to provide an experimental-based answer to the level of compressibility of arteries, b) to expand the capabilities of an experimental system, improve its reliability and operational options, c) to perform a large number of experiments on arteries in order to create a database for the determination of material parameters. Experimental evidence on the compressibility of arteries under normal physiological pressure range is provided using a precise experimental apparatus. Nineteen experiments on porcine common carotid were performed by two students and the results were analyzed by the author with the conclusion that: in the physiological pressure range (50to 200 mmHg), a relative volume change of 0.2-5% was obtained, lower compared to the sapheneous and femoral arteries (2-6% ). Most of the arteries had a relative volume change of 0.2-1.5%. Details are given in Chapter 2 which is based on a paper published in JMBBM. An apparatus used to investigate the passive and active response of arteries was enhanced.The pressure was oscillating, unstable and not controlled, the control program was not reliable, the system had only manual operation abilities and diameter was unknown during tests. These limitations were removed. The enhanced apparatus is described in detail in Chapter 3 along with numerous experiments which prove its proper functionality. Experiments for the investigation of the passive response of human left internal mammaryartery (LIMA) (one Radial) using the improved apparatus were made which demonstrate that a typical axial in-vivo stretch ratio for human LIMA is 1.1-1.15. A series of experiments attempting to activate the smooth muscle cells (SMC's) were performed. Since the obtained human arteries provided were soaked in a vasodilator (papaverine) during surgeries, the SMC response was disabled despite "washing" them in physiological solution.Due to the inability to receive un-soaked human arteries, porcine arteries were investigated. A series of seven experiments for the investigation of the active response in porcine arteries were performed showing a maximum change of 17-27% in the diameter at 80 mmHg. The results and conclusions from those experiments and experiments on human arteries for passive response are presented in Chapter 3" -- abstract.

Download or read book Mechanical Properties of Arteries written by Jan-Lucas Gade and published by Linköping University Electronic Press. This book was released on 2019-08-29 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this Licentiate of Engineering thesis, a method is proposed that identi?es the mechanical properties of arteries in vivo. The mechanical properties of an artery are linked to the development of cardiovascular diseases. The possibility to identify the mechanical properties of an artery inside the human body could, thus, facilitate disease diagnostization, treatment and monitoring. Supplied with information obtainable in the clinic, typically limited to time- resolved pressure-radius measurement pairs, the proposed in vivo parameter identi- ?cation method calculates six representative parameters by solving a minimization problem. The artery is treated as a homogeneous, incompressible, residual stress- free, thin-walled tube consisting of an elastin dominated matrix with embedded collagen ?bers referred to as the constitutive membrane model. To validate the in vivo parameter identi?cation method, in silico arteries in the form of ?nite element models are created using published data for the human abdominal aorta. With these in silico arteries which serve as mock experiments with pre-de?ned material parameters and boundary conditions, in vivo-like pressure-radius data sets are generated. The mechanical properties of the in silico arteries are then determined using the proposed parameter identi?cation method. By comparing the identi?ed and the pre-de?ned parameters, the identi?cation method is quantitatively validated. The parameters for the radius of the stress-free state and the material constant associated with elastin show high agreement in case of healthy arteries. Larger di?erences are obtained for the material constants associated with collagen, and the largest discrepancy occurs for the in situ axial prestretch. For arteries with a pathologically small elastin content, incorrect parameters are identi?ed but the presence of a diseased artery is revealed by the parameter identi?cation method. Furthermore, the identi?ed parameters are used in the constitutive membrane model to predict the stress state of the artery in question. The stress state is thereby decomposed into an isotropic and an anisotropic component which are primarily associated with the elastin dominated matrix and the collagen ?bers, respectively. In order to assess the accuracy of the predicted stress, it is compared to the known stress state of the in silico arteries. The comparison of the predicted and the in silico decomposed stress states show a close agreement for arteries exhibiting a low transmural stress gradient. With increasing transmural stress gradient the agreement deteriorates. The proposed in vivo parameter identi?cation method is capable of identifying adequate parameters and predicting the decomposed stress state reasonably well for healthy human abdominal aortas from in vivo-like data. In diesem Lizentiat der Ingenieurwissenschaften wird eine Methode zur Identifikation der mechanischen Eigenschaften von Arterien in vivo vorgestellt. Die mechanischen Eigenschaften einer Arterie sind mit der Ausbildung kardiovaskulärer Krankheiten verknüpft und deren Identifikation hat daher das Potenzial die Diagnose, die Behandlung und die Überwachung dieser Krankheiten zu verbessern. Basierend auf klinisch möglichen Messungen, die üblicherweise auf ein zeitaufgelöstes Druck-Radiussignal limitiert sind, werden sechs repräsentative Parameter durch Lösen eines Minimierungsproblems berechnet. Die sechs Parameter sind dabei die Eingangsparameter des zur Hilfe gezogenen konstitutiven Schalenmodells welches eine Arterie als eine homogene, inkompressible, restspannungsfreie und dünnwandige Röhre beschreibt. Weiterhin wird angenommen, dass die Arterienwand aus einer elastindominierten Matrix mit eingebetteten Kollagenfasern besteht. Um die in vivo Parameteridentifikationsmethode zu validieren, werden in silico Arterien in Form von Finite Elemente Modellen erstellt. Diese in silico Arterien beruhen auf publizierten Materialparametern der menschlichen Abdominalaorta und dienen als Pseudoexperimente mit vordefinierten mechanischen Eigenschaften und Randbedingungen. Mit diesen Arterien werden in vivo-ähnliche Druck-Radiussignale erstellt und anschliesend werden ihre mechanischen Eigenschaften mit Hilfe der Parameteridentifikationsmethode bestimmt. Der Vergleich der identifizierten und der vordefinierten Parameter ermöglicht die quantitative Validierung der Methode. Die Parameter des spannungsfreien Radius und der Materialkonstanten für Elastin weisen hohe Übereinstummung im Falle gesunder Arterien auf. Die Abweichung der Materialkonstanten für Kollagen sind etwas gröser und der gröste Unterschied tritt beim axialen in situ Stretch auf. Für Arterien mit einem pathologisch geringen Elastinbestandteil werden falsche Parameter identifiziert, wobei die Parameteridentifikationsmethode eine krankhafte Arterie offenlegt. Weiterhin werden mit Hilfe der identifizierten Parameter und des konstitutiven Schalenmodells der Spannungszustand in der Arterienwand berechnet. Dieser ist dabei aufgeteilt in einen isotropen und einen anisotropen Anteil. Der isotrope Anteil wird mit der elastindomierten Matrix und der anisotrope Anteil mit den Kollagenfasern verknüpft. Um die Genauigkeit des berechneten Spannungszustandes beurteilen zu können, wird dieser mit dem Zustand in den in silico Arterien verglichen. Im Fall von Arterien, die einen geringen transmuralen Spannungsgradienten aufweisen, entspricht der berechnete Spannungszustand dem in silico Zustand. Mit zunehmendem transmuralen Spannungsgradienten lässt die Übereinstimmung nach. Für die gesunde menschliche Abdominalaorta ist die entwickelte in vivo Parameteridentifikationsmethode in der Lage, basierend auf in vivo-ähnlichen Messsignalen, adäquate Parameter zu identifizieren und einen zufriedenstellenden Spannungszustand zu berechnen. I denna licentiatavhandling föreslås en metod för att identifiera mekaniska egenskaper hos artärer in vivo. De mekaniska egenskaperna är kopplade till utvecklingen av hjärt-kärlsjukdomar, och möjligheten att identifiera dessa egenskaper skulle således kunna underlätta diagnostisering, behandling och uppföljning av dessa sjukdomar. Den förslagna metoden använder kliniskt mätbara tryck-radie-signaler och löser ett minimeringsproblem för att bestämma sex parametrar som beskriver kärlets mekaniska egenskaper. Artären modelleras som ett homogent, inkompressibelt och spänningsfritt tunnväggigt rör där kärlväggen utgörs av en elastindominerad matris armerad med inbäddade kollagenfibrer. För att validera parameteridentifieringen skapas en uppsättning representativa, virtuella artärer med hjälp av finita element. Dessa in silico-artärer baseras på publicerade data för mänsklig bukaorta och används för att generera fiktiva tryckradie-signaler vilka sedan matas in i den förslagna modellen. Genom att parametrar och randvillkor för in silico-artärerna är kända fungerar dessa som en kontroll mot vilka resultatet från parameteridentifieringen kan jämföras. Parametrarna som beskriver den icke trycksatta radien och den elastindominerade matrisen visar god överensstämmelse med de in silico-artärerna för friska kärl. Större diskrepans erhålls för de parametrar som associeras med kollagenet, och den största avvikelsen erhålls för den parameter som beskriver den axiella försträckningen. För artärer med patologiskt lågt elastininnehåll identifieras felaktiga parametrar, men resultatet avslöjar ändå tydligt en sjuk artär. De identifierade parametrarna har också använts för att jämföra spänningstillst åndet i membranmodellen och in silico-artäreren. Spänningstillståndet har delats upp i en isotrop och en anisotrop komponent svarande mot, i huvudsak, den elastindominerade matrisen samt kollagenfibrerna. Resultatet visar en mycket god överensstämmelse för bägge komponenterna hos in silico-artärer med låg spänningsgradient genom väggen. Med ökande spänningsgradient försämras dock överensstämmelsen. Resultatet visar att den förslagna metoden är kapabel att identifiera adekvata parametrar och att förutsäga spänningskomponenterna i en frisk aorta.

Download or read book On the Quantification of Arterial Wall Mechanical Properties Using Invasive and Non invasive Experimental Investigations and Analytical Techniques written by Alessandro Giudici and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study of the Mechanical Behavior of a Flexible Fluid Filled Tube Simulating Arteries written by Kizhanatham Raghavachary Raman and published by . This book was released on 1964 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biomechanics of Soft Tissue in Cardiovascular Systems written by Gerhard A. Holzapfel and published by Springer. This book was released on 2014-05-04 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is written by leading experts in the field presenting an up-to-date view of the subject matter in a didactically sound manner. It presents a review of the current knowledge of the behaviour of soft tissues in the cardiovascular system under mechanical loads, and the importance of constitutive laws in understanding the underlying mechanics is highlighted. Cells are also described together with arteries, tendons and ligaments, heart, and other biological tissues of current research interest in biomechanics. This includes experimental, continuum mechanical and computational perspectives, with the emphasis on nonlinear behaviour, and the simulation of mechanical procedures such as balloon angioplasty.

Download or read book Focus on Bio Image Informatics written by Winnok H. De Vos and published by Springer. This book was released on 2016-05-20 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume of Advances Anatomy Embryology and Cell Biology focuses on the emerging field of bio-image informatics, presenting novel and exciting ways of handling and interpreting large image data sets. A collection of focused reviews written by key players in the field highlights the major directions and provides an excellent reference work for both young and experienced researchers.

Download or read book Mechanisms of Vascular Disease written by Robert Fitridge and published by University of Adelaide Press. This book was released on 2011 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: New updated edition first published with Cambridge University Press. This new edition includes 29 chapters on topics as diverse as pathophysiology of atherosclerosis, vascular haemodynamics, haemostasis, thrombophilia and post-amputation pain syndromes.

Download or read book PanVascular Medicine written by Peter Lanzer and published by Springer. This book was released on 2015-03-30 with total page 5004 pages. Available in PDF, EPUB and Kindle. Book excerpt: ​Vascular management and care has become a truly multidisciplinary enterprise as the number of specialists involved in the treatment of patients with vascular diseases has steadily increased. While in the past, treatments were delivered by individual specialists, in the twenty-first century a team approach is without doubt the most effective strategy. In order to promote professional excellence in this dynamic and rapidly evolving field, a shared knowledge base and interdisciplinary standards need to be established. Pan Vascular Medicine, 2nd edition has been designed to offer such an interdisciplinary platform, providing vascular specialists with state-of-the art descriptive and procedural knowledge. Basic science, diagnostics, and therapy are all comprehensively covered. In a series of succinct, clearly written chapters, renowned specialists introduce and comment on the current international guidelines and present up-to-date reviews of all aspects of vascular care.

Download or read book Biomechanics written by Y.C. Fung and published by Springer Science & Business Media. This book was released on 2013-03-20 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomechanics aims to explain the mechanics oflife and living. From molecules to organisms, everything must obey the laws of mechanics. Clarification of mechanics clarifies many things. Biomechanics helps us to appreciate life. It sensitizes us to observe nature. It is a tool for design and invention of devices to improve the quality of life. It is a useful tool, a simple tool, a valuable tool, an unavoidable tool. It is a necessary part of biology and engineering. The method of biomechanics is the method of engineering, which consists of observation, experimentation, theorization, validation, and application. To understand any object, we must know its geometry and materials of construc tion, the mechanical properties of the materials involved, the governing natural laws, the mathematical formulation of specific problems and their solutions, and the results of validation. Once understood, one goes on to develop applications. In my plan to present an outline of biomechanics, I followed the engineering approach and used three volumes. In the first volume, Biomechanics: Mechanical Properties of Living Tissues, the geometrical struc ture and the rheological properties of various materials, tissues, and organs are presented. In the second volume, Biodynamics: Circulation, the physiology of blood circulation is analyzed by the engineering method.

Download or read book Medical Diagnostic Techniques and Procedures written by M. R. S. Reddy and published by Alpha Science Int'l Ltd.. This book was released on 2000-01-30 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on important and evolving aspects of medical diagnostic techniques and procedures such as bioelectric phenomenon, medical imaging, biomedical signal processing, biomechanical techniques, microcirculatory techniques, optical techniques and modelling, and biomedical instrumentation covering sophisticated to low cost ideally suited for mass screening in rural areas.

Download or read book Biology of the Arterial Wall written by Bernard I. Levy and published by Springer Science & Business Media. This book was released on 2007-11-23 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biology of the Arterial Wall is intended as a general reference text concerned with the biology of the vascular cells and the blood vessel wall under physiological and pathological conditions. One of the major functions of the arteries is to maintain a continuous blood flow to the organs whatever the pressure conditions, thanks to the vasomotor tone of the smooth muscle cells. Great advances have been made over the last decade in the understanding of the endothelial cells as integrators and transducers of signals originating from the blood stream. The pluripotent control functions of the endothelial cells in the vessel wall are now well recognized. A review of endothelial functions and dysfunctions is presented. Cell biology and molecular genetic studies have now identified an array of molecules elaborated by endothelial cells and vascular smooth muscle cells and by the blood-borne elements which interact with artery cells, defending the artery against injury and modulating evolving abnormal processes. Molecules which induce or inhibit endothelial and/or smooth muscle cells are currently under great scrutiny. Angiogenesis, which plays a major role in tumor growth, but may also be beneficial as a healing process in muscle ischemia, is discussed. Apoptosis, or programmed cell death, has only recently been recognized as an essential process in blood vessel modeling and remodeling. An overview of apoptosis in the vascular system is presented. It is increasingly evident that the adjustments of the blood vessel wall are made in the presence of deforming disease processes such as hypertension and atherosclerosis. The second part of the book is concerned with the blood vessel wall in disease conditions. Several chapters review the role of the vessel and vascular cells in inflammation, and vascular remodeling during arterial hypertension and aging. One chapter is devoted to atherogenesis, atheroma and plaque instability, followed by the pathophysiology of post-angioplasty restenosis, which is a crucial issue in modern interventional cardiology.

Download or read book The Vascular Smooth Muscle Cell written by and published by Elsevier. This book was released on 1995-10-24 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last several years, the development of reagents that recognize smooth muscle-specific proteins has enabled researchers to identify smooth muscle cells (SMC) in tissue undergoing both differentiation and repair. These developments have led to increased research on SMC. The latest volume in the Biology of the Extracellular Matrix Series takes a current and all-encompassing look at this growing area of research. Devoted entirely to the subject of SMC, the book covers a diversity of topics-from SMC architecture and contractility to differentiation and gene expression in development. It also examines the proliferation and replication of SMC and its role in pharmacology and vascular disease. A must for cell, developmental, and molecular biologists, this book also will appeal to cardiologists, pathologists, and biomedical researchers interested in smooth muscle cells. Presents a molecular, genetic, and developmental perspective of the vas smooth muscle cell Overview sections highlight key points of chapters, including the clinical relevance of the research and expectations for future study Appeals to both the basic biologist and to the biomedical researcher of vascular disease

Download or read book 8th European Medical and Biological Engineering Conference written by Tomaz Jarm and published by Springer Nature. This book was released on 2020-11-29 with total page 1198 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims at informing on new trends, challenges and solutions, in the multidisciplinary field of biomedical engineering. It covers traditional biomedical engineering topics, as well as innovative applications such as artificial intelligence in health care, tissue engineering , neurotechnology and wearable devices. Further topics include mobile health and electroporation-based technologies, as well as new treatments in medicine. Gathering the proceedings of the 8th European Medical and Biological Engineering Conference (EMBEC 2020), held on November 29 - December 3, 2020, in Portorož, Slovenia, this book bridges fundamental and clinically-oriented research, emphasizing the role of education, translational research and commercialization of new ideas in biomedical engineering. It aims at inspiring and fostering communication and collaboration between engineers, physicists, biologists, physicians and other professionals dealing with cutting-edge themes in and advanced technologies serving the broad field of biomedical engineering.

Download or read book Biomechanical Modelling at the Molecular Cellular and Tissue Levels written by Gerhard A. Holzapfel and published by Springer Science & Business Media. This book was released on 2009-06-05 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cardiovascular Biomechanics written by Peter R. Hoskins and published by Springer. This book was released on 2017-02-16 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a balanced presentation of the fundamental principles of cardiovascular biomechanics research, as well as its valuable clinical applications. Pursuing an integrated approach at the interface of the life sciences, physics and engineering, it also includes extensive images to explain the concepts discussed. With a focus on explaining the underlying principles, this book examines the physiology and mechanics of circulation, mechanobiology and the biomechanics of different components of the cardiovascular system, in-vivo techniques, in-vitro techniques, and the medical applications of this research. Written for undergraduate and postgraduate students and including sample problems at the end of each chapter, this interdisciplinary text provides an essential introduction to the topic. It is also an ideal reference text for researchers and clinical practitioners, and will benefit a wide range of students and researchers including engineers, physicists, biologists and clinicians who are interested in the area of cardiovascular biomechanics.

Download or read book Data Book on Mechanical Properties of Living Cells Tissues and Organs written by Hiroyuki Abe and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: A research project entitled Biomechanics of Structure and Function of Living Cells, Tissues, and Organs was launched in Japan in 1992. This data book presents the original, up-to-date information resulting from the research project, supplemented by some of the important basic data published previously. The aim of collecting the information is to offer accurate and useful data on the mechanical properties of living materials to biomechanical scientists, biomedical engineers, medical scientists, and clinicians. The data are presented in graphs and tables (one type of data per page) arranged in an easily accessible manner, along with details of the origin of the material and the experimental method. Together with its two companion volumes, Biomechanics: Functional Adaptation and Remodeling and Computational Biomechanics, the Data Book on Mechanical Properties of Living Cells, Tissues, and Organs is a timely and valuable contribution to the rapidly growing field of biomechanics.