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cardiovascular-system
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Total 32 records
Early cancer detection in blood vessels using mobile nanosensors
, Article IEEE Transactions on Nanobioscience ; Volume 18, Issue 2 , 2019 , Pages 103-116 ; 15361241 (ISSN) ; Ahmadzadeh, A ; Wicke, W ; Jamali, V ; Schober, R ; Nasiri Kenari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose using mobile nanosensors (MNSs) for early stage anomaly detection. For concreteness, we focus on the detection of cancer cells located in a particular region of a blood vessel. These cancer cells produce and emit special molecules, so-called biomarkers, which are symptomatic for the presence of anomaly, into the cardiovascular system. Detection of cancer biomarkers with conventional blood tests is difficult in the early stages of a cancer due to the very low concentration of the biomarkers in the samples taken. However, close to the cancer cells, the concentration of the cancer biomarkers is high. Hence, detection is possible if a sensor with the ability to detect...
LVAD Functional and Transient Response Analysis and Control
, M.Sc. Thesis Sharif University of Technology ; 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...
Pulsating Pulmonary Blood Inflow in Total Cavopulmonary Connection (TCPC) after Fontan Surgery
, M.Sc. Thesis Sharif University of Technology ; 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...
Designing and Manufacturing of an Electrospinning Machine and Prediction of Mechanical Responses of Artificial Blood Vessels Using Neural Networks and Finite Element Analysis
, M.Sc. Thesis Sharif University of Technology ; Nourani, Amir (Supervisor) ; Chizari, Mahmoud (Co-Supervisor)
Abstract
Cardiovascular disease is one of the most leading causes of death in the world and one of the common methods for treating such diseases is replacing damaged blood vessels with artificial ones. Electrospinning, which is a method of producing polymer fibers, is one of the best and common methods of producing synthetic vessels. The first goal in this study was to create a suitable structure for fiber production; therefore, first, an electrospinning device and environmental chamber were designed and built. Then, the effect of alternative and uniform flow on the diameter and structure of the fibers was investigated using 15% wt. Polycaprolactone solution. The results of this study showed that the...
Beat pressure and comparing it with ascending aorta pressure in normal and abnormal conditions
, Article 4th European Conference of the International Federation for Medical and Biological Engineering, ECIFMBE 2008, Antwerp, 23 November 2008 through 27 November 2008 ; Volume 22 , 2008 , Pages 276-285 ; 16800737 (ISSN); 9783540892076 (ISBN) ; Mirzaee, M. R ; Firoozabadi, B ; Sajadi, B ; Zolfonoon, A ; Sharif University of Technology
2008
Abstract
Lumped method (Electrical analogy) is a quick and easy way to model human cardiovascular system. In this paper Lumped method is used for simulating a complete model. It describes a 36-vessel model and cardiac system of human body with details that could show hydrodynamic parameters of cardiovascular system. Also this paper includes modeling of pulmonary, atrium, left and right ventricles with their equivalent circuits. Exact modeling of right and left ventricles pressure with division of ascending aorta into 27 segments increases the accuracy of our simulation. In this paper we show that a calculated pressure for aorta from our complex circuit is near to measured pressure by using advanced...
Exact modeling of cardiovascular system using lumped method
, Article 2008 International Conference on Bioinformatics and Computational Biology, BIOCOMP 2008, Las Vegas, NV, 14 July 2008 through 17 July 2008 ; 2008 , Pages 408-417 ; 1601320558 (ISBN); 9781601320551 (ISBN) ; Mirzaee, M. R ; Firoozabadi, B ; Hassani, K ; Sharif University of Technology
2008
Abstract
Electrical analogy (Lumped method) is an easy way to model human cardiovascular system. In this paper Lumped method is used for simulating a complete model. It describes a 36-vessel model and cardiac system of human body with details that could show hydrodynamic parameters of cardiovascular system. Also this paper includes modeling of pulmonary, atrium, left and right ventricles with their equivalent circuits. Exact modeling of right and left ventricles pressure increases the accuracy of our simulation. In this paper we show that a calculated pressure for aorta from our complex circuit is near to measured pressure by using advanced medical instruments
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) ; 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) ; 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...
Analysis of the effect of ageing on rising edge characteristics of the photoplethysmogram using a modified windkessel model
, Article Cardiovascular Engineering ; Volume 7, Issue 4 , 2007 , Pages 172-181 ; 15678822 (ISSN) ; Chellappan, K ; Mohd Ali, M. A ; Singh, H ; Sharif University of Technology
2007
Abstract
Ageing is one of the main contributing factors towards increasing arterial stiffness, leading to changes in peripheral pulses propagation. Therefore the characteristics of the photoplethysmogram (PPG) pulse, especially the rising edge and peak position, are greatly affected. In this study, the PPG pulse rising edge and corresponding peak position have been investigated non-invasively in human subjects as a function of age. Fifteen healthy subjects were selected and grouped in five age intervals, from 20 to 59 years, based on their comparable systolic-diastolic blood pressure and PPG amplitude. As expected, the peripheral pulse shows a steep rise and early peak in younger subjects. With age,...
Estimation of mean radius, length and density of microvasculature using diffusion and perfusion MRI
, Article Scientia Iranica ; Volume 13, Issue 4 , 2006 , Pages 348-354 ; 10263098 (ISSN) ; Jahed, M ; Chopp, M ; Mireshghi, A ; Sharif University of Technology
Sharif University of Technology
2006
Abstract
In theory, diffusion and perfusion information in MRI maps can be combined to yield morphological information, such as capillary density, volume and possibly capillary plasma velocity. This paper suggests a new method for determination of mean radius, length and capillary density in normal regions using diffusion and perfusion MRI. Mean Transit Time (MTT), Cerebral Blood Volume (CBV), Apparent Diffusion Coefficient (ADC), pseudo-diffusion coefficient (D*) and ΔR2 and ΔR2* values were utilized to calculate mean radius, length and capillary density. To verify the proposed theory, a special protocol was designed and tested on normal regions of a male Wistar rat using obtained functions. Mean...
Healthy and diseasedin vitromodels of vascular systems
, Article Lab on a Chip ; Volume 21, Issue 4 , 2021 , Pages 641-659 ; 14730197 (ISSN) ; Mallone, A ; Nasrollahi, F ; Ostrovidov, S ; Nasiri, R ; Mahmoodi, M ; Haghniaz, R ; Baidya, A ; Salek, M. M ; Darabi, M. A ; Orive, G ; Shamloo, A ; Dokmeci, M. R ; Ahadian, S ; Khademhosseini, A ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
Irregular hemodynamics affects the progression of various vascular diseases, such atherosclerosis or aneurysms. Despite the extensive hemodynamics studies on animal models, the inter-species differences between humans and animals hamper the translation of such findings. Recent advances in vascular tissue engineering and the suitability ofin vitromodels for interim analysis have increased the use ofin vitrohuman vascular tissue models. Although the effect of flow on endothelial cell (EC) pathophysiology and EC-flow interactions have been vastly studied in two-dimensional systems, they cannot be used to understand the effect of other micro- and macro-environmental parameters associated with...
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) ; 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...