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cardiovascular-system
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Total 32 records
Functional analyses of recombinant mouse hepcidin-1 in cell culture and animal model
, Article Biotechnology Letters ; Volume 35, Issue 8 , August , 2013 , Pages 1191-1197 ; 01415492 (ISSN) ; Keyhanvar, N ; Kalhor, H. R ; Rezaei, A ; Sharif University of Technology
2013
Abstract
Hepcidin is a peptide hormone that plays an important role in iron metabolism. We have produced a recombinant mouse hepcidin-1 by using baculovirus expression system. Its expression yield was 25 μg/ml when cell culture media were supplemented with a protease inhibitor cocktail. The recombinant mouse hepcidin-1 and synthetic human hepcidin-25 had similar effects on reducing ferroportin expression in J774A cell line and in peritoneal macrophages. However, synthetic human hepcidin-25 was more efficient than recombinant mouse hepcidin-1 in reducing iron concentration in blood circulation (p < 0.01)
A novel distributed model of the heart under normal and congestive heart failure conditions
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 227, Issue 4 , 2013 , Pages 362-372 ; 09544119 (ISSN) ; Jahed, M ; Sharif University of Technology
2013
Abstract
Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison...
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) ; 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...
Life-threatening arrhythmia verification in ICU patients using the joint cardiovascular dynamical model and a bayesian filter
, Article IEEE Transactions on Biomedical Engineering ; Volume 58, Issue 10 PART 1 , 2011 , Pages 2748-2757 ; 00189294 (ISSN) ; Shamsollahi, M. B ; Sharif University of Technology
Abstract
In this paper, a novel nonlinear joint dynamical model is presented, which is based on a set of coupled ordinary differential equations of motion and a Gaussian mixture model representation of pulsatile cardiovascular (CV) signals. In the proposed framework, the joint interdependences of CV signals are incorporated by assuming a unique angular frequency that controls the limit cycle of the heart rate. Moreover, the time consequence of CV signals is controlled by the same phase parameter that results in the space dimensionality reduction. These joint equations together with linear assignments to observation are further used in the Kalman filter structure for estimation and tracking. Moreover,...
Numerical Multiscale Modelingof Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; 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...
Simulating the Effect of Cuff Pressure on Brachial Artery for Calculating the Photoplethysmography(PPG) Singnal
, M.Sc. Thesis Sharif University of Technology ; 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...
Numerical Simulation of Mass Transport in Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; 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...
At first, the physiological data of the systemic arteries have been used to simulate a one-dimensional geometry...
Drug Delivery in Cardiovascular System with Multi Scale Approach
, M.Sc. Thesis Sharif University of Technology ; 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...
Robust control of LVAD based on the sub-regional modeling of the heart
, Article Scientia Iranica ; Volume 23, Issue 6 , 2016 , Pages 2934-2943 ; 10263098 (ISSN) ; Jahed, M ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
Left Ventricular Assist Devices (LVAD) have received renewed interest as a bridge-to-transplantation as well as a bridge-to-recovery device. Ironically, reports of malfunction and complications have hindered the growth of this device. In particular, the main concern is LVAD's susceptibility to excessive backlash and suction as a result of ows that are either too low or high, respectively. This study utilizes a well-established physiological model of the cardiovascular system as a reliable platform to study a proposed adaptive robust controller for a rotary motor based LVAD which overcomes such shortcomings. Proposed controller performance is evaluated by comparing simulated natural heart...
Air Pollution Effects on Mortality
, M.Sc. Thesis Sharif University of Technology ; 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 ; 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...
Modeling of the Cardiovascular System using Breathing Stimuli for Evaluation of the Autonomic Nervous System
, Ph.D. Dissertation Sharif University of Technology ; 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
,
M.Sc. Thesis
Sharif University of Technology
;
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....
One Dimensional Simulation of Systemic and Pulmonary Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; 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....
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) ; 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...
Distributed Cardiovascular System Modeling
, M.Sc. Thesis Sharif University of Technology ; 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,...
Design and Fabrication of Engineered Biomaterials for Tissue Engineering Applications such as Cardiovascular System
, M.Sc. Thesis Sharif University of Technology ; Shamlou, Amir (Supervisor)
Abstract
Cardiovascular diseases are the leading cause of death all over the world, even more common than cancers. The first reason of mortality in Iran according to statistics is the occlusion of coronary arteries. Unfortunately almost one third of patients doesn’t have enough blood vessels to be used in the bypass surgery and need artificial vessels. These artificial blood vessels with small diameters (less than 6 mm) will fail quickly. As a result there is an increasing demand for tissue engineered blood vessels which are capable of enduring high blood pressures. An artificial blood vessel should mimic both structure and mechanical properties of the real one. Blood vessels have layered structures,...
Numerical and One Dimensional Modeling of Cardiovascular System Along with Lumped Parameter Modeling of the Heart
, M.Sc. Thesis Sharif University of Technology ; 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...
Development of an Integrated Hybrid Model of Human Cardiovascular and Respiratory System for Control Study purposes
, M.Sc. Thesis Sharif University of Technology ; 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 ; 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...