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Total 32 records

    Exact simulating of human arteries using lumped model and probing constriction in femoral and carotid arteries

    , Article American Journal of Applied Sciences ; Volume 6, Issue 5 , 2009 , Pages 834-842 ; 15469239 (ISSN) Mirzaee, M. R ; Ghasemalizadeh, O ; Firoozabadi, B ; Sharif University of Technology
    2009
    Abstract
    Problem statement: Modeling Human cardiovascular system was always an important issue from long past because by doing such modeling, investigation in cardiovascular system and its abnormities would be simpler. One of the most effective ways to do such modeling is using lumped method (Electrical analogy). Approach: Lumped method was used for simulating a complete model in this approach. A 36-vessel model was chosen to make equivalent circuit of lumped method from it. This complicated circuit includes equivalent segment for arteries, pulmonary, atrium, left and right ventricles. Furthermore, in this complex circuit some additional points were considered to improve this method. Some of the most... 

    Conceptual modeling of cardiovascular sounds

    , Article 2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005, Shanghai, 1 September 2005 through 4 September 2005 ; Volume 7 VOLS , 2005 , Pages 2308-2311 ; 05891019 (ISSN); 0780387406 (ISBN); 9780780387409 (ISBN) Pouladian, M ; Tehrani Fard, A. A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2005
    Abstract
    In this paper, it is shown that the main source of mechanical energy of cardiovascular (CV) system i.e., rhythmic heart contraction is transformed to the oscillations of the CV walls and blood flow, and finally CV acoustical waves. These waves propagate through both blood flow (hemodynamical pathways) and tissues (viscoelastical pathways) toward the skin. Nonetheless, the CV walls could be assumed as the source of acoustical waves, since they act as the interface between blood flows and other tissues including skin. After obtaining the approximate accelerations of CV walls from pressure-flow (PF) models, we also needed to model the viscoelastical pathways until the skin. Some improvements on... 

    Numerical Multiscale Modelingof Cardiovascular System

    , M.Sc. Thesis Sharif University of Technology Yousefi, Amir (Author) ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    One of the main reasons of brain attack is stenosis in Carotid bifurcation. As a result, it's a major field of interest for a large group of scientists including medical doctors and engineers. In the engineering fields a large number of studies have been done on this topic based on Numerical Simulation. As blood boundary conditions in this region strictly depend on the rest of the body's vascular system, the problem is the definition of the boundary condition in this approach. In addition, because of lack of enough hardware sources simulation of the whole blood system is impossible; thus the rest of the system should be simulated based on radical methods with less details. In this project a... 

    An age index for vascular system based on photoplethysmogram pulse contour analysis

    , Article IFMBE Proceedings ; Volume 21 IFMBE, Issue 1 , 2008 , Pages 125-128 ; 16800737 (ISSN); 9783540691389 (ISBN) Chellappan, K ; Mohd Ali, M. A ; Zahedi, E ; Sharif University of Technology
    Springer Verlag  2008
    Abstract
    An approach based pulse on contour analysis is proposed for the development of an aging index for the vascular system. The approach is non-invasive, using photoplethysmography (PPG), which is in wide clinical use. A probe is applied to the subject's finger-tip to provide a measure of the pulse waveform. The measured waveforms are filtered, digitized and post-processed. Individual pulses are extracted and the best pulse was selected by using the best pulse selection algorithm. Pulse contour analysis is then performed with specially formulated PPG fitness equation. Results of measurements taken from 72 subjects are reported. The age range of the subjects was from 19 to 68 years, all of them... 

    Effects of physical exercise on the photoplethysmogram waveform

    , Article 2007 5th Student Conference on Research and Development, SCORED, Selangor, 11 December 2007 through 12 December 2007 ; 2007 ; 1424414709 (ISBN); 9781424414703 (ISBN) Chellappan, K ; Zahedi, E ; Mohd Ali, M. A ; Sharif University of Technology
    2007
    Abstract
    Photoplethysmography is a non-invasive method which is suitable to estimate vascular compliance. Photoplethysmogram (PPG) waveform has been used to evaluate vascular characteristic changes due to exercise. Quantification of the primary and secondary peak position is of interest as a potential objective, individualized measure of the level of exercise that a subject has achieved with respect to a baseline status, prior to the beginning of the exercise session. The modified bicycle ergonomic protocol was selected for this experiment. Two different signal processing methods were employed in processing the PPG waveform to characterize its changes through a single parameter. Both, the visual... 

    Simulating the Effect of Cuff Pressure on Brachial Artery for Calculating the Photoplethysmography(PPG) Singnal

    , M.Sc. Thesis Sharif University of Technology Shiri, Farhad (Author) ; Firoozabadi, Bahar (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)
    Abstract
    One of the most important reasons of death in today’s world is the diseases related to cardiovascular system. Hypercholesterolemia is one of the most common forms of these diseases. There are a lot of experiments for diagnosing this disease, which are classified into two groups: invasive and noninvasive experiments. One of the well-known noninvasive experiments in this area is the photoplethysmography in which the changes of the photoplethysmography signal can reveal some valuable information about the cardiovascular system’s health.The objective of this study is to simulate the photoplethysmography experiment considering the clinical conditions of the experiment. In this work, the obtained... 

    Drug Delivery in Cardiovascular System with Multi Scale Approach

    , M.Sc. Thesis Sharif University of Technology Rahmati, Mahmood (Author) ; Vosughi, Manouchehr (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Supervisor)
    Abstract
    Particle retention and clearance is a major concern in the treatment of pulmonary diseases. Inhaled materials into the nasal and lung airways include gases/vapors, liquid droplets and soluble/insoluble particulate matter which can be toxic or therapeutic (or both). For example, nanoparticles (NPs), as part of nanomedicine, are now being used as drug carriers for passive and active targeting of solid tumors and inflamed tissue. However, natural and especially manmade NPs can also be harmful, such as carbon nanotubes (CNTs), asbestos fibers and ambient toxic pollutants, based on epidemiological and pathological studies of occupational and environmental exposures. In fact, ultrafine particles... 

    Modeling of the Cardiovascular System using Breathing Stimuli for Evaluation of the Autonomic Nervous System

    , Ph.D. Dissertation Sharif University of Technology Goldouzian, Layli Sadat (Author) ; Zahedi, Edmond (Supervisor) ; Jehed, Mehran (Supervisor) ; Zarzoso, Vicente (Supervisor)
    Abstract
    Autonomic nervous system (ANS) controls involuntary activities of the body, e.g. heartbeat function and blood circulation. Common tests used for evaluation of the functionality of ANS system in regulation of the cardiovascular system include heart rate variability (HRV) analysis and studying the changes in heart rate or blood pressure during deep respiration, sit-to-stand or head-up tilt table test and Valsalva maneuver. Test parameters affect the amplitude of the variations of the cardiovascular signals. Therefore, in the recent years, analysis and modeling of the interaction between the relevant signals, e.g. heart rate, blood pressure and respiration, have been widely used for the... 

    Numerical and One Dimensional Modeling of Cardiovascular System Along with Lumped Parameter Modeling of the Heart

    , M.Sc. Thesis Sharif University of Technology Salehi, Sarah (Author) ; Firoozabadi, Bahar (Supervisor) ; Saidi, Mohammad Saeed (Co-Advisor)
    Abstract
    Cardiovascular diseases are major causes of morbidity and mortality in the world. In order to prevent or reduce these diseases, engineers and scientists are concerned to find solutions. In this way, it is important to know about the blood flow and its changes in various diseases. By using simulation methods, diagnosis can be very easier. In this study, a system of arterial tree consisting of 93 systemic arteries along with 7 pulmonary arteries is considered. In other words, this model contains 100 systemic and pulmonary arteries that encompass central and peripheral arteries. Other parts of this model are cerebral vasculature and coronary arteries. Cerebral arteries, also called circle of... 

    LVAD Functional and Transient Response Analysis and Control

    , M.Sc. Thesis Sharif University of Technology Talebian Ardestani, Mohammad Taher (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    When heart failure occurred, revascularization to body’s organs and consequently covering the metabolic demands of different sections faces with problem. Chronic heart failure is the first reason of mortality all over the world. Traditional treatment for CHF at end stage is heart transplantation. But some of patients don’t have the opportunity to benefit from heart transplantation because of aging, health conditions and lack of donors. On the other hand, Left Ventricular Assist Devices that are using for supporting a ventricle suffering from failure face with basic chalanges for example, backflow in lower speeds and suction in higher speed. These constrictions necessitate maximum and minimum... 

    Modeling of photoplethysmography signal for quantitative analysis of endothelial cells during reactive hyperemia

    , Article 2012 19th Iranian Conference of Biomedical Engineering, ICBME 2012 ; 2012 , Pages 174-178 ; 9781467331302 (ISBN) Shiri, F ; Firoozabadi, B ; Saidi, M. S ; Sharif University of Technology
    2012
    Abstract
    In this study, at first the cardiovascular system is modeled based on the 1D method and then the simulation of the reactive hyperemia experiment has been applied on the model. In this simulation, by applying a cuff at the brachial artery, the flow downstream of the cuff is occluded. Then with releasing the cuff immediately, a large amount of shear stress, about 4 times the basal amount, is applied downstream of the cuff and consequently to the endothelial cells in a very short moment. Considering a reported experimental transfer function between shear stress and vasodilation, the increase of the artery diameter due to the sudden increase of the shear stress is obtained. Finally, the... 

    One Dimensional Simulation of Systemic and Pulmonary Cardiovascular System

    , M.Sc. Thesis Sharif University of Technology Ghadamsoltani, Elias (Author) ; Firoozabadi, Bahar (Supervisor) ; Saidi, Mohammad Saeid (Supervisor)
    Abstract
    Cardiovascular diseases are most common causes of deaths in the whole world. Nowadays, engineers and scientists in various fields become intent on finding solutions for prevention and recovery of these diseases. In this way, it is very important to know about the blood flow in arterial systems and its changes in various diseases. Numerical simulation of the blood flow beside of experimental studies could be very useful in this way. One dimensional simulation among various methods of numerical simulation was chosen to simulate a cardiovascular system since it has smaller computational cost and ability to modeling of whole arterial systems. It also is useful in extraction of medical indexes.... 

    Numerical Simulation of Mass Transport in Cardiovascular System

    , M.Sc. Thesis Sharif University of Technology Haji Gholami, Iman (Author) ; Firoozabadi , Bahar (Supervisor) ; Saidi, Mohammad Said (Supervisor)
    Abstract
    In this dissertation, mass transport in cardiovascular system has been simulated using one-dimensional approach. As one-dimensional simulation has computation cost less than that of the three-dimensional simulations, and as it is more precise than lumped models, they are extensively used in the study of the phenomena in cardiovascular system. In addition, such an approach is more useful in the extraction of medical indices. In this study, a one-dimensional geometry of the systemic arteries has been used to solve momentum and continuity equations using characteristics method.
    At first, the physiological data of the systemic arteries have been used to simulate a one-dimensional geometry... 

    Air Pollution Effects on Mortality

    , M.Sc. Thesis Sharif University of Technology Moghani, Vahid (Author) ; Rahmati, Mohammad Hossein (Supervisor) ; Vesal, Mohammad (Supervisor)
    Abstract
    In this paper evaluate the short-term effects of air pollution on the mortality rate caused by cardiovascular problems, respiratory problems, digestive problems and tumors and cancers. This is done by using daily mortality data of Tehran, Tabriz, Mashad, Shiraz, Ahwaz and Isfahan during the years 1390 to 1394, we also use daily measurements of pollutant levels including Carbon-monooxcide, Sulfure-dioxide, Oxides of Nitrogen, Ozone and Particulate matters in the same period. The effects are estimad by looking at the relation of daily mortality in each city along with its pollution level. By controling for the weather conditions and city and month fixed effects, we find significant positive... 

    Development of an Integrated Detail Model of Human Respiratory System for Control

    , M.Sc. Thesis Sharif University of Technology Arianpour, Mehrdad (Author) ; Bozorgmehri, Ramin (Supervisor)
    Abstract
    In this thesis, the latest human respiratory system is extended such that it addresses the effect of blood acidity on the performance of the human respiratory system. Since the model does not take into account any controller, two PI controllers proposed by Bental have been used to simulate the closed loop behavior of the respiratory system. Since, in the original model blood pH is considered as a constant value, the extended model has been used for the case where the blood pH pumped by heart is assumed to be and the obtained results have been compared with those of the original model. The similarity of the results shows the extended model to be valid for the normal case. Model since t he... 

    Numerical and One Dimensional Modeling of Cardiovascular System

    , M.Sc. Thesis Sharif University of Technology Molaei, Mehdi (Author) ; Saeedi, Mohammad Saeed (Supervisor) ; Firoozabadi, Bahar (Supervisor)
    Abstract
    Cardiovascular diseases are most common causes of deaths in the whole world. Nowadays, engineers and scientists in various fields become intent on finding solutions for prevention and recovery of these diseases. In this way, it is very important to know about the blood flow in arterial systems and its changes in various diseases. Numerical simulation of the blood flow beside of experimental studies could be very useful in this way. One dimensional simulation among various methods of numerical simulation was chosen to simulate a cardiovascular system since it has smaller computational cost and ability to modeling of whole arterial systems. It also is useful in extraction of medical indexes.... 

    Distributed Cardiovascular System Modeling

    , M.Sc. Thesis Sharif University of Technology Khani, Mehrdad (Author) ; Jahed, Mehran (Supervisor)
    Abstract
    Simulation of cardiovascular system functionality during various physiological conditions is essential at different diagnostic and clinical levels. A first step in studying the roots of cardiovascular diseases and abnormal activity is to study a practical yet complete model of the cardiovascular system. In this thesis we introduced a new approach for defining the distributed model of the cardiovascular system. Initially, we chose an appropriate subsystem, namely Arch of Aorta, and proposed a distributed model for it. The elements of the proposed model were nonlinear RLC elements that simulate resistance, blood viscosity and vessel elasticity respectively. To minimize the system complexity,... 

    Development of an Integrated Hybrid Model of Human Cardiovascular and Respiratory System for Control Study purposes

    , M.Sc. Thesis Sharif University of Technology Kehtari, Payam (Author) ; Bozorgmehri, Ramin (Supervisor)
    Abstract
    Mathematical models are used for describing physical systems to make it possible to study and investigate the behavior of these systems and compare their performance and improve them. For this reason, a mathematical model for cardiovascular system and respiratory system is used to study how these two systems interact. The cardiovascular system model and the respiratory system model comprise four and two compartments, respectively. In fact, the combined model contains the left and right ventricles, body tissue, lung, systemic blood circulation, and pulmonary compartments. Heart rate and alveolar ventilation are assumed to be the quantities through them the central nervous system controls the... 

    Modeling the Relationship between Central Aortic Pressure and Radial Photoplethysmogram in Flow-mediated Dilation Test

    , Ph.D. Dissertation Sharif University of Technology Parsafar, Mohammad Habib (Author) ; Vosughi Vahdat, Bijan (Supervisor) ; Zahedi, Edmond (Supervisor)
    Abstract
    According to the World Health Organization, about 35% of deaths worldwide are due to cardiovascular diseases, therefore the evaluation of vascular endothelial function has great prognostic and diagnostic value for cardiovascular diseases. The conventional noninvasive method for endothelial function evaluation is the measurement of flow-mediated dilation in brachial artery using ultrasound imaging (FMD-US). As the accuracy of FMD-US depends on the operator's skill and the resolution of the ultrasound images, this method has not been adopted. In this work, we propose to use a low cost, easily-accessible surrogate signal, the photoplethysmogram (PPG) to implement the FMD test. Whereas previous... 

    Pulsating Pulmonary Blood Inflow in Total Cavopulmonary Connection (TCPC) after Fontan Surgery

    , M.Sc. Thesis Sharif University of Technology Moradi, Hamed (Author) ; Sayadi, Hassan (Supervisor) ; Firoozabadi, Bahar (Supervisor) ; Navabi Shirazi, Mohammad Ali (Co-Supervisor) ; Malakan Rad, Elaheh (Co-Supervisor)
    Abstract
    Patients with a single ventricle disease who have undergone Fontan surgery have always had long-term complications. These complications include pulmonary artery stiffness and decreased ability to exercise. In fact, due to removal of the right ventricle from the circulatory system, blood pressure and pulsatility inflow to total cavopulmonary connection (TCPC) are reduced following this surgery. Creating waves (radial displacement) on the IVC (Inferior Vena Cava) wall can increase pulmonary flow pulsations. The Objective of this study is to test the effect of induced wave amplitude on the pulmonary flow pulsations at the rest condition. Computational fluid dynamic (CFD) simulations were...