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1

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.

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2

Hinch, Robert. "Mathematical models of the heart". Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270632.

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3

Romero-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/.

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4

Thalassoudis, 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.

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5

Satterlee, 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.

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In this study, lumped parameter cardiovascular modeling has been used to understand the influence of muscle properties on mechanical dyssynchrony (MD) as well as general muscle dynamics. Incorporating viscous influence into the model allowed for an expanded view when analyzing muscle parameter response to MD. A unique method of ventricle segmentation was introduced that allowed fast analysis of regional and global ventricular properties. This segmentation process produced a ventricle with four identical sections each consisting of separately tunable muscle properties in the form of minimum and maximum elastance, elastance waveform delay, and myocardial viscous friction, yet these regional sections remained globally dependent. Elastance waveform delay proved to be the most influential property on MD as measured by internal flow fraction (IFF), followed by regional elastance magnitude, and finally regional viscosity influence. Due to the unique segmentation of this model, two metrics for IFF were derived: (1) the "true" IFF (IFF-4seg) and (2) the IFF as would be measured by an ideal conductance catheter (IFF-CC). The results of IFF-CC versus IFF-4seg show that conductance catheters are not capable of measuring IFF during a side-to-side volume transfer within the stacked cylinder under measurement. Finally, unique energetic situations were observed with this model that point to likely myocardium remodeling situations.
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6

Lemmon, 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.

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7

McCorkle, 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.

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In 1966 Mark Kac posed an interesting question regarding vibrating membranes and the sounds they make. His article entitled "Can One Hear the Shape of a Drum?", which appeared in The American Mathematical Monthly, generated much interest and scholarly debate. The evolution of Kac's intriguing question will be the subject of this project.
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8

Sher, 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.

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9

Nash, 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.

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Global and regional mechanics of the cardiac ventricles were investigated using an anatomicallyaccurate computational model formulated from concise mathematical descriptions ofthe left and right ventricular wall geometries and the non-homogeneous laminar microstructureof cardiac muscle. The finite element method for finite deformation elasticity was developedfor the analysis and included specialised coordinate systems, interpolation schemesand parallel processing techniques for greater computational efficiency.The ventricular mechanics model incorporated the fully orthotropic pole-zero constitutivelaw, based on the three-dimensional architecture of myocardium, to account for the nonlinearmaterial response of resting cardiac muscle, relative to the three anatomically relevant axes.A fibre distribution model was introduced to reconcile some of the pole-zero constitutiveparameters with direct mechanical properties of the tissue (such as the limiting strainsestimated from detailed physiological observations of the collagen helices that surroundmyofibres), whilst other parameters were estimated from in-vitro biaxial tension tests onthin sections of myocardium. A non-invasive approach to in-vivo myocardial materialparameter estimation was also developed, based on a magnetic resonance imaging techniqueto effectively tag ventricular wall tissue.The spatially non-homogeneous distribution of myocardial residual strain was accounted forin the ventricular mechanics model using a specialised growth tensor. A simple model of fluidshift was formulated to account for the changes in local tissue volume due to movement ofintramyocardial blood. Contractile properties of ventricular myofibres were approximatedusing a quasi-static relationship between the fibre extension ratio, intracellular calciumconcentration and active fibre stress, and the framework has been developed to include amore realistic model of active myocardial mechanics, which could be coupled to a realisticdescription of the time-varying spread of electrical excitation throughout the ventricularwalls. Simple volumetric cavity models were incorporated to investigate the effects of arterialimpedance on systolic wall mechanics.Ventricular mechanics model predictions of the cavity pressure versus volume relationships,longitudinal dimension changes, torsional wall deformations and regional distributions ofmyocardial strain during the diastolic filling, isovolumic contraction and ejection phasesof the cardiac cycle showed good overall agreement with reported observations derivedfrom experimental studies of isolated and in-vivo canine hearts. Predictions of the spatialdistributions of mechanical stress at end-diastole and end-systole are illustrated.
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10

Wandler, 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.

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Diagnosing cardiac patient problems contains many uncertainties, and to fully diagnose the patient's condition usually requires a lengthy drug regimen to see what works and what does not. Compounding this problem is that even after the correct drug regimen has been discovered, the underlying cause for the problem may remain a mystery. Thus, the uncertainty and the length of time required to provide an accurate and adequate solution makes it very difficult to provide quality care to the patient. Templeton and others have shown that lumped cardiac muscle parameters can be extracted from an isolated heart by injecting small volumes at high frequencies relative to the heart rate and measuring the pressure response to this volume change. Using the Hill muscle model of two springs and a dash pot to portray the different elements of the cardiac muscle, the pressure and volume relationship makes it possible to calculate these muscle parameters using frequency response analysis techniques. The hypothesis to be tested is "Is it possible to develop a method to test cardiac muscle for stiffness, resistance, and contractile force from measuring ventricular pressure and injected flow?" To test this hypothesis, an isovolumic heart model is developed and allowed to develop pressure, along with a small volume injected to create a pressure response. Analysis of the pressure and flow waveforms produces a measured value of the cardiac model parameter values to compare to the model values. Results from injecting small volume changes into a mathematical heart model show that it is possible to extract the muscle model parameters of non-linear resistance, inertia of the fluid and muscle, and stiffness of the muscle while filling and contracting. The injected frequency and volume were varied to find usable conditions, both with regard to the calculations and the practical limits. Analyzing the error between the measured and model values for a large number of different combinations of model parameters shows an average error of less than 1%.
Iron Range Engineering
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11

Wilkerson, Patrick Wayne. "Quantification of mitral regurgitation using corrected doppler measurements". Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17302.

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12

Sharma, 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.

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Imaging of myocardial viability using the delayed enhancement technique currently provides high image contrast between infarcted and normal tissue with the aid of a magnetization prepared fast gradient echo pulse sequence following the administration of an extracellular contrast agent. However, there exists a degree of image contrast variability and subjectivity due to contrast agent kinetics and user-specified imaging parameters. Also, the technique has not been explored at higher field strengths (3T), which offer greater inherent signal-to-noise ratio. The overall goal of this study is to compare magnetic resonance delayed contrast enhancement of myocardial infarction at 1.5T and 3T. The analysis was conducted by first developing a comprehensive mathematical simulation of the imaging sequence, which allowed modification of various imaging parameters. Simulations were performed to optimize the sequence for flip angle and inversion time, as well as to evaluate the influence of other image parameters that affected contrast. These theoretical results were validated experimentally with phantoms. In vivo post-contrast T1 measurements at 1.5T and 3T from normal volunteers (n=10) and patients (n=5) provided more precise input into mathematical optimization simulations. In both populations, longer T1 values were found at 3T compared to 1.5T for normal (pre-contrast: 1.24 .06s vs. 1.07 .05s; post-contrast: 0.34-0.59 vs. 0.33-0.54s, n=15) and infarcted myocardium (pre-contrast: 1.27 .06s vs. 1.04 .06s; post-contrast: 0.25-0.37s vs. 0.23-0.32s, n=5). Corresponding simulations using these T1 values revealed an infarct-to-normal tissue contrast gain at 3T of approximately 25%. In vivo image contrast between infarcted and normal tissue following contrast administration was also higher at 3T by approximately 37%. In conclusion, there was good correlation between mathematical simulations of delayed enhancement and experimental results, enabling parameters to be compared and optimized offline given input T1 values. Although contrast-enhanced viability imaging at 3T suffered from artifacts due to field, RF, and inversion pulse inhomogeneity, these results suggest that 3T offers higher contrast-to-noise ratio than 1.5T for this application.
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13

Lutsyk, 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.

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Ce travail a été réalisé en cotutelle entre l'Université Nationale de Technologie de Ternopil Ivan Pul'uj (TNTU, Ukraine) et l’Université Blaise Pascal (France). Il appartient au domaine scientifique de la biomécanique et de l'informatique. Le but de l'étude est de développer les modèles et les méthodes de traitement des signaux biomécaniques cardiaques par les systèmes de diagnostic assisté par ordinateur avec une précision accrue, informativité et de la complexité de calcul inférieure. La méthode d'analyse statistique du rythme cardiaque a été mise au point. Cette méthode possède une plus grande précision et informativité par rapport aux méthodes connues d'analyse du rythme cardiaque. Dans cette thèse, le logiciel existant de l'analyse des signaux cardiaques biomécaniques a été améliorée par l'ajout de nouveaux modules logiciels, qui mettent en œuvre les nouvelles méthodes de l'analyse du rythme cardiaque et de l'analyse morphologique des signaux cardiaques biomécaniques
This 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
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14

Nicolin, Jean-Pierre. "Evaluation des echanges thermiques par rayonnement dans un local soumis a un incendie". Paris 6, 1987. http://www.theses.fr/1987PA066555.

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Developpement des modules informatiques pour un logiciel de simulation de feu de compartiment (fisba), etudiant et comparant plusieurs techniques d'evaluation des transferts thermiques radiatifs. Amelioration d'une methode a six-flux pour milieu confine; presentation d'une methode des zones par quadratures numeriques (souplesse du maillage); consideration de modeles plus grossiers mais plus rapides en temps de calcul, par simplification des integrales d'echange. Bon accord constate entre ces methodes et avec celle de hottel; considerations sur la justification de l'emploi de modeles simples a cause de l'incertitude sur les proprietes physiques des materiaux
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15

Mannan, 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.

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[Truncated abstract] The main objective of this study was to develop and validate a demographic/epidemiologic Markov model for population modelling/forecasting of CARPs as well as CHD deaths and incidence in Western Australia using population, linked hospital morbidity and mortality data for WA over the period 1980 to 2000. A key feature of the model was the ability to count events as individuals moved from one state to another and an important aspect of model development and implementation was the method for estimation of model transition probabilities from available population data. The model was validated through comparison of model predictions with actual event numbers and through demonstration of its use in producing forecasts under standard extrapolation methods for transition probabilities as well as improving the forecasts by taking into account various possible changes to the management of CHD via surgical treatment changes. The final major objective was to demonstrate the use of model for performing sensitivity analysis of some scenarios. In particular, to explore the possible impact on future numbers of CARPs due to improvements in surgical procedures, particularly the introduction of drug eluting stents, and to explore the possible impact of change in trend of CHD incidence as might be caused by the obesity epidemic. ... When the effectiveness of PCI due to introduction of DES was increased by reducing Pr(CABG given PCI) and Pr(a repeat PCI), there was a small decline in the requirements for PCIs and the effect seemed to have a lag. Finally, in addition to these changes when other changes were incorporated which captured that a PCI was used more than a CABG due to a change in health policy after the introduction of DES, there was a small increase in the requirements for PCIs with a lag in the effect. Four incidence scenarios were developed for assessing the effect of change in secular trends of CHD incidence as might be caused by the obesity epidemic in such a way that they gradually represented an increasing effect of obesity epidemic (assuming that other risk factors changed favourably) on CHD incidence. The strategy adopted for developing the scenarios was that based on past trends the most dominant component of CHD incidence was first gradually altered and finally the remaining components were altered. iv The results showed that if the most dominant component of CHD incidence, eg, Pr(CHD - no history of CHD) levelled off and the trends in all other transition probabilities continued into future, then the projected numbers of CABGs and PCIs for 2001-2005 were insensitive to these changes. Even increasing this probability by as much as 20 percent did not alter the results much. These results implied that the short-term effect on projected numbers of CARPs caused by an increase in the most dominant component of CHD incidence, possibly due to an ?obesity epidemic, is small. In the final incidence scenario, two of the remaining CHD incidence components-Pr(CABG - no history of CHD) and Pr(CHD death - no CHD and no history of CHD) were projected to level off over 2001-2005 because these probabilities were declining over the baseline period of 1998-2000. The projected numbers of CABGs were more sensitive (compared to the previous scenarios) to these changes but PCIs were not.
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16

Oshiyama, 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.

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Orientadores: José Wilson Magalhães Bassani, Rosana Almada Bassani
Tese (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
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17

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.

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L’objectif de ce travail est la modélisation mathématique et numérique du procédé de refusions à l'arc sous vide (VAR), dans le but d'optimiser la refusion d'alliages de titane chargés. En effet, l'intervalle de solidification important de ces alliages les rend sensibles à la formation de défauts de solidification liés à la circulation du liquide interdendritique. Dans le cadre de cette étude, des mesures effectuées par analyse thermique différentielle (ATD) ont permis de quantifier les intervalles de solidification de ces alliages de titane. Le modèle développé décrit les transferts couplés de chaleur, de soluté et de quantité de mouvement en écoulement turbulent, lors de la croissance et de la solidification du lingot VAR. Les transferts au sein de la zone pâteuse sont explicitement pris en compte, celle-ci étant assimilée à un milieu poreux. Le modèle relie directement les paramètres opératoires aux profils de puits liquide, à l'hydrodynamique du bain métallique (convection thermosolutale et forces électromagnétiques) ainsi qu'à l'intensité de la ségrégation dans le lingot. Les simulations effectuées concernent une fusion en four pilote d'un lingotin de titane marqué au cuivre, ainsi que deux fusions industrielles de [Bêta]Cez. Elles ont permis de mettre en évidence l'effet du brassage électromagnétique sur l'écoulement complexe du métal liquide. La prise en compte des transferts au sein de la zone pâteuse permet également de mieux comprendre les phénomènes à l'origine de la macroségrégation. Il apparait que les conditions de brassage des fusions de [Bêta]Cez simulées ont une influence considérable sur l'intensité de la macroségrégation, et donc sur le risque d'apparition de défauts de solidification. Le mécanisme de formation de défauts du type canaux ségrégés, a également été mis en évidence. Dans le cas du [Bêta]Cez, il a été attribué à la convection solutale ascendante de métal liquide fortement appauvri en molybdène. Le modèle peut ainsi être utilisé avec profit afin de choisir les conditions de fusion permettant de minimiser la macroségrégation et donc le risque de formation de défauts
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18

Murphey, Carey Richard. "Mathematical models of atrial and ventricular myocytes from the rabbit heart". Thesis, 1991. http://hdl.handle.net/1911/16466.

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Mathematical models of rabbit atrial and ventricular myocytes that are based on quantitative voltage clamp data from emzymatically isolated cardiac myocytes have been developed. These models are capable of accurately simulating the transmembrane ionic currents recorded in response to a step change in membrane potential (whole-cell voltage clamp response), the nonpropagated membrane action potential (MAP), and the frequency-dependent action potential waveshape changes occurring in response to variations in rate of stimulation. Rectangular pulse, ramp and action potential voltage-clamp measurements of the transmembrane ionic currents have allowed us to model a number of processes thought to be important during repolarization. These computations provide important biophysical insights into the electrophysiological activity of atrial and ventricular cells and their associated intra- and extracellular ionic concentration changes. The present model also has useful predictive capabilities. We have used the model to: (1) estimate the intracellular $Ca\sp{2+}$ transient in these myocytes and to compare the relative occupancy of the $Ca\sp{2+}$ binding sites in the contractile proteins with known cellular mechanical activity, and (2) predict the response of the atrial cell to potassium current blockade via $BaCl\sb2$ to the bathing medium.
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19

Hsuen, Yi-Wen, i 薛尹雯. "The Role of Calcium in Heart Operation and Its Related Mathematical Models". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/97293632791068701358.

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碩士
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.
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20

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.

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In order to have a complete understanding of the relationship between physical activity (PA) and health, it is essential to be able to accurately assess PA in free-living situations. The purpose of this study was to use three accelerometers located on the dominant ankle, hip, and wrist and a heart rate (HR) monitor to estimate energy expenditure (EE) compared to measured EE while completing activities of daily living (ADL). The regression equation developed showed a significant relationship (P < 0.05) with EE. Together, HR and the hip-worn accelerometer explained 73.4% of the variance in EE with HR accounting for 59.3% (P < 0.05). Type of activity, the wrist-, and ankle-worn accelerometer each explained an additional 5%, 3% and 3% of the variance in EE, respectively (P < 0.05). The regression equation developed is a good predictor of EE during selected ADL, and allows researchers to more accurately quantify free-living PA.
School of Physical Education, Sport, and Exercise Science
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21

Bittihn, Philip. "Complex Structure and Dynamics of the Heart". Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BBB6-B.

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22

Jain, Ravi 1967. "Intelligent techniques for the diagnosis of coronary artery disease / Ravi Jain". 1998. http://hdl.handle.net/2440/19356.

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Bibliography: leaves 179-190.
xii, 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
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Hojatpanah, Roozbeh. "Empirical study of acoustic instability in premixed flames: measurements of flame transfer function". 2012. http://hdl.handle.net/1805/3366.

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Indiana University-Purdue University Indianapolis (IUPUI)
In 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.
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Deep, Debanjan. "A study of blood flow in normal and dilated aorta". Thesis, 2013. http://hdl.handle.net/1805/4440.

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Indiana University-Purdue University Indianapolis (IUPUI)
Atherosclerotic 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.
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