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Control Algorithm of Multi-agent Systems in Special Paths With an Applied Consideration in Biomechanical Engineering to Perform Operations of Interior Treatments
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
In this project Deployment of multi-agent systems was studied. Maximum coverage over a point or curve or area is desired in deployment of multi-agent systems. A facility location optimization function was derived from geometrical concepts such as voronoi, n- geometric median and fermat-weber problem by optimization of which the deployment of multi-agent systems is performed. First, it is assumed that dynamic of agents is first order and second order .Next, it is assumed that agents are in a fluid. In all situations a suitable control algorithm was derived to optimize the facility location function to perform deployment. Next, another facility location function was derived by optimization...
Heat Transfer Modeling of Ultrasounic Hyperthermia
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
Ultrasound hyperthermia is a commonly used noninvasive approach to destroy cancer tumors. High Intensity Focused Ultrasound (HIFU) is a technique based on hyperthermia. It creates short and local elevations of temperature at a focus site within the tissue of interest. The main goal of HIFU is to maintain the temperature between 50 and 100 °C for a few seconds (typically less than 10 s), in order to cause tissue necrosis. In order to predict the effects of hyperthermia, accurate and effective modeling is needed. This study considers a 3D simulation of the hyperthermia based on HIFU method in the liver tissue. Temperature distribution and lesion volume changes, with a temperature of above...
Modeling Kidney Vascular Structure Based on Parametric L-system
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fatolah (Supervisor) ; Bozorgmehry Boozarjomehry, Ramin (Supervisor)
Abstract
Kidney is one of the most complicated organs in terms of functionality and physiology due to its complicated unique vascular structure. Previous investigations have focused on specific characteristics like length and diameter. Most of these methods are based on Image Processing techniques which prevent a comprehensive study in growth and changes of the vascular system. Lindenmyaer system (L-system) is a parallel rewriting system and a type of formal grammar and had been used to create graphs and natural patterns. By absorbing the physiological characteristics of the kidney and integrating them into parametric L-system, a highly dense and accurate vascular system could be generated with few...
Fsi simulation of a healthy coronary bifurcation for studying the mechanical stimuli of endothelial cells under different physiological conditions
, Article Journal of Mechanics in Medicine and Biology ; Volume 15, Issue 5 , October , 2015 ; 02195194 (ISSN) ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2015
Abstract
Atherosclerosis is a world-spread and well-known disease. This disease strongly relates to the endothelial cells (ECs) function. Normally, the endothelial cells align in the flow direction in the atheroprotected sites; however, in the case of atheroprone sites these cells orient randomly. The mechanical stimuli such as wall shear stress and strains could determine the morphology and function of the endothelial cells. In the present study, we numerically simulated the left main coronary artery (LCA) and its branches to left anterior descending (LAD) and left circumflex coronary (LCX) artery using fluid-structure interaction (FSI) modeling. The results were presented as longitudinal and...
Controlling differentiation of stem cells for developing personalized organ-on-chip platforms
, Article Advanced Healthcare Materials ; Volume 7, Issue 2 , 2018 ; 21922640 (ISSN) ; Jafari, P ; Sheikh Hassani, M ; Heidary Araghi, B ; Mohammadi, M. H ; Ghafari, A. M ; Hassanpour Tamrin, S ; Pezeshgi Modarres, H ; Rezaei Kolahchi, A ; Ahadian, S ; Sanati Nezhad, A ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Organ-on-chip (OOC) platforms have attracted attentions of pharmaceutical companies as powerful tools for screening of existing drugs and development of new drug candidates. OOCs have primarily used human cell lines or primary cells to develop biomimetic tissue models. However, the ability of human stem cells in unlimited self-renewal and differentiation into multiple lineages has made them attractive for OOCs. The microfluidic technology has enabled precise control of stem cell differentiation using soluble factors, biophysical cues, and electromagnetic signals. This study discusses different tissue- and organ-on-chip platforms (i.e., skin, brain, blood–brain barrier, bone marrow, heart,...
3D Bioprinting of oxygenated cell-laden gelatin methacryloyl constructs
, Article Advanced Healthcare Materials ; Volume 9, Issue 15 , 2020 ; Darabi, M. A ; Nasiri, R ; Sangabathuni, S ; Ertas, Y. N ; Alem, H ; Hosseini, V ; Shamloo, A ; Nasr, A. S ; Ahadian, S ; Dokmeci, M. R ; Khademhosseini, A ; Ashammakhi, N ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
Cell survival during the early stages of transplantation and before new blood vessels formation is a major challenge in translational applications of 3D bioprinted tissues. Supplementing oxygen (O2) to transplanted cells via an O2 generating source such as calcium peroxide (CPO) is an attractive approach to ensure cell viability. Calcium peroxide also produces calcium hydroxide that reduces the viscosity of bioinks, which is a limiting factor for bioprinting. Therefore, adapting this solution into 3D bioprinting is of significant importance. In this study, a gelatin methacryloyl (GelMA) bioink that is optimized in terms of pH and viscosity is developed. The improved rheological properties...
Pulsatile blood flow in total cavopulmonary connection: a comparison between Y-shaped and T-shaped geometry
, Article Medical and Biological Engineering and Computing ; Volume 55, Issue 2 , 2017 , Pages 213-224 ; 01400118 (ISSN) ; Firoozabadi, B ; Saidi, M. S ; Monjezi, M ; Navabi Shirazi, M. A ; Malakan Rad, E ; Sharif University of Technology
Springer Verlag
2017
Abstract
Single-ventricle anomaly is a hereditary heart disease that is characterized by anatomical malformations. The main consequence of this malformation is desaturated blood flow, which without proper treatment increases the risk of death. The classical treatment is based on a three-stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure, in which inferior vena cava is directly connected to pulmonary arteries without going through the ventricle. This connection is called total cavopulmonary connection (TCPC). After surgery, the single ventricle supplies adequate and saturated systemic blood flow to the body; however,...
Margination and adhesion of micro- and nanoparticles in the coronary circulation: A step towards optimised drug carrier design
, Article Biomechanics and Modeling in Mechanobiology ; Volume 17, Issue 1 , 2018 , Pages 205-221 ; 16177959 (ISSN) ; Shamloo, A ; Sharif University of Technology
Springer Verlag
2018
Abstract
Obstruction of left anterior descending artery (LAD) due to the thrombosis or atherosclerotic plaques is the leading cause of death worldwide. Targeted delivery of drugs through micro- and nanoparticles is a very promising approach for developing new strategies in clot-busting or treating restenosis. In this work, we modelled the blood flow characteristics in a patient-specific reconstructed LAD artery by the fluid–solid interaction method and based on physiological boundary conditions. Next, we provided a Lagrangian description of micro- and nanoparticles dynamics in the blood flow considering their Brownian motion and the particle–particle interactions. Our results state that the number of...
Personalised deposition maps for micro- and nanoparticles targeting an atherosclerotic plaque: attributions to the receptor-mediated adsorption on the inflamed endothelial cells
, Article Biomechanics and Modeling in Mechanobiology ; Volume 18, Issue 3 , 2019 , Pages 813-828 ; 16177959 (ISSN) ; Forouzandehmehr, M ; Sharif University of Technology
Springer Verlag
2019
Abstract
Endothelial inflammation as a prominent precursor to atherosclerosis elicits a distinct pathological surface expression of particular vascular proteins. To exhibit a site-specific behaviour, micro- and nanoparticles, as carriers of therapeutics or imaging agents, can distinguish and use these proteins as targeted docking sites. Here, a computational patient-specific model capturing the exclusive luminal qualities has been developed to study the transport and adsorption of particles decorated with proper antibodies over an atherosclerotic plaque located in the LAD artery of the patient. Particles, in nano- and micron sizes, have been decorated with Sialyl Lewisx (sLex), P-selectin aptamer...
A mechanical model for morphological response of endothelial cells under combined wall shear stress and cyclic stretch loadings
, Article Biomechanics and Modeling in Mechanobiology ; Volume 15, Issue 5 , 2016 , Pages 1229-1243 ; 16177959 (ISSN) ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
Springer Verlag
Abstract
The shape and morphology of endothelial cells (ECs) lining the blood vessels are a good indicator for atheroprone and atheroprotected sites. ECs of blood vessels experience both wall shear stress (WSS) and cyclic stretch (CS). These mechanical stimuli influence the shape and morphology of ECs. A few models have been proposed for predicting the morphology of ECs under WSS or CS. In the present study, a mathematical cell population model is developed to simulate the morphology of ECs under combined WSS and CS conditions. The model considers the cytoskeletal filaments, cell–cell interactions, and cell–extracellular matrix interactions. In addition, the reorientation and polymerization of...
Spatiotemporal registration and fusion of transthoracic echocardiography and volumetric coronary artery tree
, Article International Journal of Computer Assisted Radiology and Surgery ; Volume 16, Issue 9 , 2021 , Pages 1493-1505 ; 18616410 (ISSN) ; Behnam, H ; Fatemizadeh, E ; Faghihi Langroudi, T ; Bayat, F ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Purpose: Cardiac multimodal image fusion can offer an image with various types of information in a single image. Many coronary stenosis, which are anatomically clear, are not functionally significant. The treatment of such kind of stenosis can cause irreversible effects on the patient. Thus, choosing the best treatment planning depend on anatomical and functional information is very beneficial. Methods: An algorithm for the fusion of coronary computed tomography angiography (CCTA) as an anatomical and transthoracic echocardiography (TTE) as a functional modality is presented. CCTA and TTE are temporally registered using manifold learning. A pattern search optimization algorithm, using...
Targeted drug delivery of magnetic microbubble for abdominal aortic aneurysm: an in silico study
, Article Biomechanics and Modeling in Mechanobiology ; Volume 21, Issue 2 , 2022 , Pages 735-753 ; 16177959 (ISSN) ; Ebrahimi, S ; Ghorbani, G ; Alishiri, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Targeted drug delivery (TDD) to abdominal aortic aneurysm (AAA) using a controlled and efficient approach has recently been a significant challenge. In this study, by using magnetic microbubbles (MMBs) under a magnetic field, we investigated the MMBs performance in TDD to AAA based on the amount of surface density of MMBs (SDMM) adhered to the AAA lumen. The results showed that among the types of MMBs studied in the presence of the magnetic field, micromarkers are the best type of microbubble with a −50 % increase in SDMM adhered to the critical area of AAA. The results show that applying a magnetic field causes the amount of SDMM adhered to the whole area of AAA to increase −1.54 times...
Investigation of the different parameters contributing to bubble sticking inside physiological bifurcations
, Article Medical and Biological Engineering and Computing ; Volume 60, Issue 2 , 2022 , Pages 599-618 ; 01400118 (ISSN) ; Saidi, M. S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Gas embolotherapy (GE) is a developing medical method which can be utilized either as an autonomous therapeutic method to treat vascularized solid tumors, or it can be combined with other medical procedures—such as high-intensity focused ultrasound—to improve their efficiency. This paper is dedicated to investigating the different parameters which influence bubble lodging inside human vasculature via 2D-modeling of bubble dynamics in arteries’ and arterioles’ bifurcations which are potential sticking positions. Values used in the simulations are in accordance with the non-dimensional physiological numbers. It is found out that inlet pressure plays a decisive role in bubble lodging; the lower...
Prevascularized micro-/nano-sized spheroid/bead aggregates for vascular tissue engineering
, Article Nano-Micro Letters ; Volume 13, Issue 1 , 2021 ; 23116706 (ISSN) ; Nasrollahi Boroujeni, N ; Jahangiri, S ; Rabiee, N ; Rabiee, M ; Makvandi, P ; Akhavan, O ; Varma, R. S ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Efficient strategies to promote microvascularization in vascular tissue engineering, a central priority in regenerative medicine, are still scarce; nano- and micro-sized aggregates and spheres or beads harboring primitive microvascular beds are promising methods in vascular tissue engineering. Capillaries are the smallest type and in numerous blood vessels, which are distributed densely in cardiovascular system. To mimic this microvascular network, specific cell components and proangiogenic factors are required. Herein, advanced biofabrication methods in microvascular engineering, including extrusion-based and droplet-based bioprinting, Kenzan, and biogripper approaches, are deliberated with...
Automatic segmentation, detection, and diagnosis of abdominal aortic aneurysm (AAA) using convolutional neural networks and hough circles algorithm
, Article Cardiovascular Engineering and Technology ; Volume 10, Issue 3 , 2019 , Pages 490-499 ; 1869408X (ISSN) ; Mohammadi, M ; Dehlaghi, V ; Ahmadi, A ; Sharif University of Technology
Springer New York LLC
2019
Abstract
Purpose: An abdominal aortic aneurysm (AAA) is known as a cardiovascular disease involving localized deformation (swelling or enlargement) of aorta occurring between the renal and iliac arteries. AAA would jeopardize patients’ lives due to its rupturing risk, so prompt recognition and diagnosis of this disorder is vital. Although computed tomography angiography (CTA) is the preferred imaging modality used by radiologist for diagnosing AAA, computed tomography (CT) images can be used too. In the recent decade, there has been several methods suggested by experts in order to find a precise automated way to diagnose AAA without human intervention base on CT and CTA images. Despite great...
Aortic dissection is determined by specific shape and hemodynamic interactions
, Article Annals of Biomedical Engineering ; Volume 50, Issue 12 , 2022 , Pages 1771-1786 ; 00906964 (ISSN) ; Marlevi, D ; Bruse, J. L ; Nezami, F. R ; Moradi, H ; Fortunato, R. N ; Maiti, S ; Billaud, M ; Edelman, E. R ; Gleason, T. G ; Sharif University of Technology
Springer
2022
Abstract
The aim of this study was to determine whether specific three-dimensional aortic shape features, extracted via statistical shape analysis (SSA), correlate with the development of thoracic ascending aortic dissection (TAAD) risk and associated aortic hemodynamics. Thirty-one patients followed prospectively with ascending thoracic aortic aneurysm (ATAA), who either did (12 patients) or did not (19 patients) develop TAAD, were included in the study, with aortic arch geometries extracted from computed tomographic angiography (CTA) imaging. Arch geometries were analyzed with SSA, and unsupervised and supervised (linked to dissection outcome) shape features were extracted with principal component...
A neumerical method to investigate the effect of ultrasonic waves on capillary imbibition
, Article 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 ; Volume 5 , 2010 , Pages 3246-3250 ; 9781617386671 (ISBN) ; Karimi, R ; Najafi, I ; Ghotbi, C ; Ghaedian, M ; Sharif University of Technology
Society of Petroleum Engineers
2010
Abstract
A lot of laboratory experiments have been carried out to investigate each aspect of ultrasonic wave s role on fluid flow behavior through porous media. Despite all experimental works, little attention has been paid for modeling the ultrasonic wave influence on capillary imbibition, which is the main mechanism of production in fractured reservoirs. At this work the process of imbibition with and without applying ultrasonic waves is mathematically modeled by modification of piston-like model. In contrast to this model s assumption, in which mobility ratio is assumed to be constant, here permeability variation due to increase in water saturation is considered in numerical solution. To evaluate...
The importance of fluid-structure interaction simulation for determining the mechanical stimuli of endothelial cells and atheroprone regions in a coronary bifurcation
, Article Scientia Iranica ; Volume 23, Issue 1 , 2016 , Pages 228-237 ; 10263098 (ISSN) ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
Sharif University of Technology
2016
Abstract
The function and morphology of Endothelial Cells (ECs) play a key role in atherosclerosis. The mechanical stimuli of ECs, such as Wall Shear Stress (WSS) and arterial wall strain, greatly inuence the function and morphology of these cells. The present article deals with computations of these stimuli for a 3D model of a healthy coronary artery bifurcation. The focus of the study is to propose an accurate method for computations of WSS and strains. Two approaches are considered: Coupled simultaneous simulation of arterial wall and blood flow, called fluid-Structure Interaction (FSI) simulation, and decoupled, which simulates each domain (fluid and solid domain) separately. The study...
Introducing a new definition towards clinical detection of microvascular changes using diffusion and perfusion MRI
, Article Scientia Iranica ; Volume 12, Issue 1 , 2005 , Pages 109-115 ; 10263098 (ISSN) ; Jiang, Q ; Chopp, M ; Jahed, M ; Sharif University of Technology
Sharif University of Technology
2005
Abstract
Based on MRI diffusion and perfusion, a new criterion for detection and the healing progress of damaged tissue is suggested. The study is based on the ratio of capillary radii in symmetrical damaged and normal tissue neighboring spaces. The Apparent Diffusion Coefficient (ADC) and Cerebral Blood Flow (CBF) were measured in the brain tissues of six male Wistar rats utilizing suggested MRI measurement techniques. The ADC values of damaged and normal regions were (392 ± 34.1) × 10-6 mm2s-1 and (659 ± 40.7) × 10-6 mm2s-1, respectively. The CBF values of damaged and normal regions were 14.5 ± 10.13 ml/min/ 100 g and 125 ± 41.03 ml/min/100 g, respectively. The geometrical parameters of the...
Numerical study of the effect of hemodynamic variables on LDL concentration through the single layer of the Left Anterior Descending coronary artery (LAD) under the heart pulse
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 236, Issue 7 , 2022 , Pages 994-1008 ; 09544119 (ISSN) ; Seyedhossein, S. S ; Firoozabadi, B ; MomeniLarimi, M ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Heart attack is one of the most common causes of death in the world. Coronary artery disease is the most recognized cause of heart attack whose onset and progression have been attributed to low-density lipoprotein (LDL) passing through the wall of the artery. In this paper, hemodynamic variables as well as the concentration of LDL through the coronary porous artery at the Left Anterior Descending coronary artery (LAD), and its first diagonal branch (D1) under the heart motion investigated using computational simulation. The geometry that has been studied in this paper is the first bifurcation of Left Anterior Descending (LAD) that has been placed on a perimeter of hypothetical sphere...