Dissertations / Theses on the topic 'Heart Sounds Mathematical models'
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Ewing, Gary John. "A new approacch to the analysis of the third heart sound." Title page, contents and summary only, 1988. http://web4.library.adelaide.edu.au/theses/09SM/09sme95.pdf.
Full textHinch, Robert. "Mathematical models of the heart." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270632.
Full textRomero-Vivas, Eduardo. "Hidden Markovian models applied to the analysis of heart sounds for diagnostic purposes." Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/425886/.
Full textThalassoudis, Kym. "Numerical studies of flow through prosthetic heart valves /." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09PH/09pht365.pdf.
Full textSatterlee, Cody Michael. "The Effects of Spatial and Temporal Properties on a Viscoelastic Model of the Dyssynchronous Canine Heart." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29327.
Full textLemmon, Jack David Jr. "Three-dimensional computational modeling of fluid-structure interaction : study of diastolic function in a thin-walled left heart model." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/15912.
Full textMcCorkle, Tricia Dawn. "Math, music, and membranes: A historical survey of the question "can one hear the shape of a drum"?" CSUSB ScholarWorks, 2005. https://scholarworks.lib.csusb.edu/etd-project/2933.
Full textSher, Anna. "Modelling local calcium dynamics and the sodium/calcium exchanger in ventricular myocytes." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670114.
Full textNash, Martyn. "Mechanics and material properties of the heart using an anatomically accurate mathematical model." Thesis, University of Auckland, 1998. http://hdl.handle.net/2292/84.
Full textWandler, Jeff. "Calculating Cardiovascular Lumped-Parameter Model Values by Injecting Small Volume Perturbations in an Isovolumic Heart." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/28884.
Full textIron Range Engineering
Wilkerson, Patrick Wayne. "Quantification of mitral regurgitation using corrected doppler measurements." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17302.
Full textSharma, Puneet. "Comparison of Delayed Contrast-Enhanced Magnetic Resonance Imaging of Myocardial Viability at 1.5 and 3 Tesla." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6911.
Full textLutsyk, Nadiia. "Modeling and methods of biomechanical heart signals processing using the conditional cyclic random process." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22726.
Full textThis work has been performed under the co-tutelle agreement between Ternopil Ivan Pul’uj National Technical University in Ternopil (TNTU, Ukraine) and the University Blaise Pascal in Clermont-Ferrand (France). It belongs to the scientific field of biomechanics and informatics. The aim of the study is to develop the mathematical models and methods of the processing of biomechanical heart signals in computer-based diagnostic systems with increased accuracy, informativeness and lower computational complexity. The method of statistical analysis of heart rhythm was developed, which is characterised by higher accuracy and informativeness compared with the known methods of heart rhythm analysis. In this thesis, the existing software of the analysis of biomechanical heart signals was improved by means of adding new software modules that implement the new methods of the analysis of heart rhythm and morphologic analysis of biomechanical heart signals
Nicolin, Jean-Pierre. "Evaluation des echanges thermiques par rayonnement dans un local soumis a un incendie." Paris 6, 1987. http://www.theses.fr/1987PA066555.
Full textMannan, Haider Rashid. "Development and use of a Monte Carlo-Markov cycle tree model for coronary heart disease incidence-mortality and health service usage with explicit recognition of coronary artery revascularization procedures (CARPs)." University of Western Australia. School of Population Health, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0101.
Full textOshiyama, Natália Ferreira 1985. "Modelo matemático de potencial de ação e transporte de Ca2+ em miócitos ventriculares de ratos neonatos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260926.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-24T11:00:56Z (GMT). No. of bitstreams: 1 Oshiyama_NataliaFerreira_D.pdf: 4721295 bytes, checksum: 5ed8a9a173462afb13315f133bf426f8 (MD5) Previous issue date: 2014
Resumo: O potencial de ação (PA), variação do potencial elétrico através da membrana (Em), é gerado por fluxos iônicos através de canais e transportadores, cuja função e expressão pode ser alterada por hormônios, neurotransmissores, drogas e toxinas. Trata-se de um sistema complexo, para o qual os modelos computacionais constituem ferramenta importante de estudo. No presente trabalho, foi desenvolvido um modelo de PA e transporte de Ca2+ em células ventriculares de ratos neonatos, para o que foi necessário medir a concentração intracelular de Na+ ([Na+]i) e a corrente de Na+ (INa) em cardiomiócitos isolados, sobre as quais há pouca informação na literatura, e as correntes de Ca2+ (ICa), transiente de saída (Ito) e retificadora tardia (IK) de K+, além do próprio PA para melhorar a precisão do modelo. Medições em miócitos de ratos adultos foram realizadas para comparação. Foi observada menor excitabilidade das células de ratos neonatos, o que poderia ser explicado por um deslocamento da curva de ativação de INa de ~10 mV para a direita, i.e., a ativação dos canais de Na+ ocorreu em Em menos negativos e numa faixa mais ampla de Em em miócitos de neonatos do que em células de adultos. Outra diferença encontrada foi com relação à densidade de INa, ~2 vezes maior em células de neonatos. O maior influxo de Na+ poderia causar um aumento da [Na+]i durante a atividade em células de recém-nascidos, que foi confirmado pela medição de [Na+]i. No entanto, não houve aumento significativo quando ICa e o trocador Na+/Ca2+ (NCX) foram inibidos, o que indica que o aumento da [Na+]i se deve mais ao efluxo de Ca2+ via NCX do que ao influxo pelos canais de Na+ do sarcolema. Além disso, observou- se maior duração do PA em miócitos de neonatos, que poderia ser explicada pela menor densidade observada de correntes repolarizantes (Ito e IK). No entanto, não foi detectada diferença entre idades na densidade de ICa. Dados de simulações mostraram que o retículo sarcoplasmático (RS) é a principal fonte do Ca2+ ativador da contração e que a liberação fracional de Ca2+ do RS nos ratos neonatos é menor que nos adultos, confirmando dados experimentais deste laboratório. Portanto, o modelo poderá ser utilizado para predizer possíveis alterações eletrofisiológicas dos cardiomiócitos de ratos neonatos em diferentes condições.
Abstract: The action potential (AP), a change in electrical potential across the membrane (Em), is generated by ionic fluxes through channels and transporters, of which function and expression may be affected by hormones, neurotransmitters, drugs and toxins. Computational models constitute an important tool for the study of this highly non-linear and complex system. In this work, a model of AP and Ca2+ transport in ventricular cells of neonatal rats was developed. It was necessary to measure the intracellular Na+ concentration ([Na+]i) and the Na+ current (INa), for which information in the literature is scarce, and the Ca2+ current (ICa), as well as the outward transient (Ito) and delayed rectifier (IK) K+ currents, in addition to the AP itself, to improve the accuracy of the model. Measurements from adult rat myocytes were also made in order to compare these developmental phases. It was observed that neonatal rat cells are less excitable, which could be explained by a ~10 mV shift to the right of the channel activation curve, i.e., Na+ channels activation occured at less negative Em value and over a higher range of Em compared to adult cells. On the other hand, INa density was twice as great as that in adults. This might promote increase in [Na+]i during activity in cells from newborns, which was confirmed by measurement of [Na+]i. Nonetheless, significant Na+ accumulation was suppressed when ICa and the Na+ / Ca2+ exchanger (NCX) were inhibited, which indicates that the increase in [Na+]i probably depends more on Ca2+ efflux via NCX than on the influx through sarcolemmal Na+ channels. The longer AP duration in neonatal myocytes could be explained by the lower density of the repolarizing currents (Ito and IK). However, age-dependent difference in ICa density was not observed. Simulation data agreed with experimental data from this laboratory regarding the sarcoplasmic reticulum (SR) as the main source of Ca2+ during excitation-contraction coupling and the lower SR fractional release in neonatal than in adult myocytes. In conclusion, the present model may be used to predict possible electrophysiological alterations in developing cardiomyocytes under different conditions.
Doutorado
Engenharia Biomedica
Doutora em Engenharia Elétrica
Hans, Stéphane. "Modélisation des transferts couplés de chaleur, de soluté et de quantité de mouvement lors de la refusion à l'arc sous vide (VAR) : application aux alliages de titane." Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL023N.
Full textMurphey, Carey Richard. "Mathematical models of atrial and ventricular myocytes from the rabbit heart." Thesis, 1991. http://hdl.handle.net/1911/16466.
Full textHsuen, Yi-Wen, and 薛尹雯. "The Role of Calcium in Heart Operation and Its Related Mathematical Models." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/97293632791068701358.
Full text靜宜大學
應用數學研究所
98
Calcium ion plays many important roles in physiological processes. Many physiological signals are transmitted via calcium ion dynamics, such as calcium transients, calcium oscillation patterns, calcium waves… In this thesis, we mainly discuss the role of calcium in heart operation. Calcium ion is a linker between electrical and mechanical functional parts of heart and skeletal muscles, the so-called Excitation-Contraction Coupling (ECC). We will explore how the calcium ion moves between extracellular and intracellular regions or intracellular compartments and how it regulates some ion channel releases such as ryanodine receptor channel (RyR). Moreover, various mathematical models for calcium dynamics will be discussed, such as common pool model, stochastic local-control model, and coupled LCC-RyR gating model.
Kirschner, Monica M. "Assessment of energy expenditure and physical activity intensity through simultaneous use of heart rate monitoring and accelerometry." 2012. http://liblink.bsu.edu/uhtbin/catkey/1670055.
Full textSchool of Physical Education, Sport, and Exercise Science
Bittihn, Philip. "Complex Structure and Dynamics of the Heart." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BBB6-B.
Full textJain, Ravi 1967. "Intelligent techniques for the diagnosis of coronary artery disease / Ravi Jain." 1998. http://hdl.handle.net/2440/19356.
Full textxii, 189 leaves : ill. ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
This thesis proposes a genetic-programming-based classifier system for the diagnosis of coronary artery disease. Based on genetic programming, a software system called Evolutionary Pre-Processor has been developed as a new method for the automatic extraction of non-linear features for supervised classification. Two different hybrid intelligent system techniques are presented; fuzzy systems integrated with genetic algorithms and genetic algorithms combined with back-propagation algorithms. All approaches were tested on a real-world problem of coronary artery disease data.
Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 1998
Hojatpanah, Roozbeh. "Empirical study of acoustic instability in premixed flames: measurements of flame transfer function." 2012. http://hdl.handle.net/1805/3366.
Full textIn order to conform to pollutant-control regulations and minimize NOx emissions, modern household boilers and central heating systems are moving toward premixed combustors. These combustors have been successful with regards to emissions along with efficiency. However, their implementation has been associated with acoustical instability problems that could be solved through precise optimization in design rather than trial and error experimentation. This thesis introduces an experimental apparatus, which is designed to investigate the acoustic instability problem at the flame level. The goal is an experimental determination of the flame transfer function and comparison of the experimental data with a theoretical model of the flame. An experimental procedure is designed to diagnose the origins of the combustion instabilities by measurement of the flame transfer function. This research is carried out in three steps. The first step is to understand the acoustic instability problem through study of the theoretical models of the flame transfer function and selection of a model, which is most functional in industrial applications. A xiii measurement technique for the flame transfer function is developed according to the required accuracy in measurements, repeatability, and configurability for a wide range of operating conditions. Subsequently, an experimental apparatus is designed to accommodate the flame transfer function measurement technique. The components of the acoustic system are carefully sized to achieve precise measurement of the system parameters such as flows, pressures, and acoustic responses, and the apparatus is built. The apparatus is operated to measure the flame transfer function at several operating conditions. The experimentally measured flame transfer function is compared with a theoretical model for further verification. The experimental apparatus provides an improved assessment of the acoustic instability problem for industrial applications.
Deep, Debanjan. "A study of blood flow in normal and dilated aorta." Thesis, 2013. http://hdl.handle.net/1805/4440.
Full textAtherosclerotic lesions of human beings are common diagnosed in regions of arte- rial branching and curvature. The prevalence of atherosclerosis is usually associated with hardening and ballooning of aortic wall surfaces because of narrowing of flow path by the deposition of fatty materials, platelets and influx of plasma through in- timal wall of Aorta. High Wall Shear Stress (WSS) is proved to be the main cause behind all these aortic diseases by physicians and researchers. Due to the fact that the atherosclerotic regions are associated with complex blood flow patterns, it has believed that hemodynamics and fluid-structure interaction play important roles in regulating atherogenesis. As one of the most complex flow situations found in cardio- vascular system due to the strong curvature effects, irregular geometry, tapering and branching, and twisting, theoretical prediction and in vivo quantitative experimental data regarding to the complex blood flow dynamics are substantial paucity. In recent years, computational fluid dynamics (CFD) has emerged as a popular research tool to study the characteristics of aortic flow and aim to enhance the understanding of the underlying physics behind arteriosclerosis. In this research, we study the hemo- dynamics and flow-vessel interaction in patient specific normal (healthy) and dilated (diseased) aortas using Ansys-Fluent and Ansys-Workbench. The computation con- sists of three parts: segmentation of arterial geometry for the CFD simulation from computed tomography (CT) scanning data using MIMICS; finite volume simulation of hemodynamics of steady and pulsatile flow using Ansys-Fluent; an attempt to perform the Fluid Structure Simulation of the normal aorta using Ansys-Workbench. Instead of neglecting the branching or smoothing out the wall for simplification as a lot of similar computation in literature, we use the exact aortic geometry. Segmen- tation from real time CT images from two patients, one young and another old to represent healthy and diseased aorta respectively, is on MIMICS. The MIMICS seg- mentation operation includes: first cropping the required part of aorta from CT dicom data of the whole chest, masking of the aorta from coronal, axial and saggital views of the same to extract the exact 3D geometry of the aorta. Next step was to perform surface improvement using MIMICS 3-matic module to repair for holes, noise shells and overlapping triangles to create a good quality surface of the geometry. A hexahe- dral volume mesh was created in T-Grid. Since T-grid cannot recognize the geometry format created by MIMICS 3-matic; the required step geometry file was created in Pro-Engineer. After the meshing operation is performed, the mesh is exported to Ansys Fluent to perform the required fluid simulation imposing adequate boundary conditions accordingly. Two types of study are performed for hemodynamics. First is a steady flow driven by specified parabolic velocity at inlet. We captured the flow feature such as skewness of velocity around the aortic arch regions and vortices pairs, which are in good agreement with open data in literature. Second is a pulsatile flow. Two pulsatile velocity profiles are imposed at the inlet of healthy and diseased aorta respectively. The pulsatile analysis was accomplished for peak systolic, mid systolic and diastolic phase of the entire cardiac cycle. During peak systole and mid-systole, high WSS was found at the aortic branch roots and arch regions and diastole resulted in flow reversals and low WSS values due to small aortic inflow. In brief, areas of sudden geometry change, i.e. the branch roots and irregular surfaces of the geom- etry experience more WSS. Also it was found that dilated aorta has more sporadic nature of WSS in different regions than normal aorta which displays a more uniform WSS distribution all over the aorta surface. Fluid-Structure Interaction simulation is performed on Ansys-WorkBench through the coupling of fluid dynamics and solid mechanics. Focus is on the maximum displacement and equivalent stress to find out the future failure regions for the peak velocity of the cardiac cycle.