Search for: cardiovascular-system
Total 32 records
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 ; Chizari, Mahmoud
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...
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
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...
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
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
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
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
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...
Design and Fabrication of Engineered Biomaterials for Tissue Engineering Applications such as Cardiovascular System, M.Sc. Thesis Sharif University of Technology ; Shamlou, Amir
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,...
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
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)
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
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...
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
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,...
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
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...
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
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...
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
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,...