Search for: heart-function
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    Introducing a distributed model of the heart

    , Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 419-424 ; 21551774 (ISSN) ; 9781457711992 (ISBN) Ravanshadi, S ; Jahed, M ; Sharif University of Technology
    Conventional models of cardiovascular system (CV) frequently lack required detail. Once utilized to study the heart function, these models focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the CV system. It utilizes non-invasive blood flow and pressure seed data and temporal cardiac muscle regional activation to predict the operation of the heart. Proposed localized analysis considers specific regions of the heart, namely base, mid and apex sections of the left ventricle. This modular system is based on a hydraulic electric analogy model, estimating desired parameters, namely resistance (R), compliance (C),... 

    Investigation of the effect of high +Gz accelerations on human cardiac function

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 27 , 2013 , Pages 54-63 ; 17516161 (ISSN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology
    This study investigates the effect of body acceleration on human cardiac function. Finite element analysis is conducted to simulate geometrical and mechanical properties of human heart. Heart geometrical modeling in three-dimension is performed by segmentation of cardiac MRI images. The nonlinear mechanical behavior of myocardium is modeled by Mooney-Rivlin, Polynomial, Ogden and Yeoh hyperelastic material models. Stress-strain curves of myocardial tissue are obtained from experimental compression tests on bovine heart samples. The experimental results are employed for the evaluation of material coefficients by the nonlinear least squares method. Among hyperelastic models, the Yeoh model... 

    Type V collagen in scar tissue regulates the size of scar after heart injury

    , Article Cell ; Volume 182, Issue 3 , 2020 , Pages 545-562.e23 Yokota, T ; McCourt, J ; Ma, F ; Ren, S ; Li, S ; Kim, T. H ; Kurmangaliyev, Y. Z ; Nasiri, R ; Ahadian, S ; Nguyen, T ; Tan, X. H. M ; Zhou, Y ; Wu, R ; Rodriguez, A ; Cohn, W ; Wang, Y ; Whitelegge, J ; Ryazantsev, S ; Khademhosseini, A ; Teitell, M. A ; Chiou, P. Y ; Birk, D. E ; Rowat, A. C ; Crosbie, R. H ; Pellegrini, M ; Seldin, M ; Lusis, A. J ; Deb, A ; Sharif University of Technology
    Cell Press  2020
    Scar tissue size following myocardial infarction is an independent predictor of cardiovascular outcomes, yet little is known about factors regulating scar size. We demonstrate that collagen V, a minor constituent of heart scars, regulates the size of heart scars after ischemic injury. Depletion of collagen V led to a paradoxical increase in post-infarction scar size with worsening of heart function. A systems genetics approach across 100 in-bred strains of mice demonstrated that collagen V is a critical driver of postinjury heart function. We show that collagen V deficiency alters the mechanical properties of scar tissue, and altered reciprocal feedback between matrix and cells induces... 

    Two statistical methods for resolving healthy individuals and those with congestive heart failure based on extended self-similarity and a recursive method

    , Article Journal of Biological Physics ; Volume 32, Issue 6 , 2006 , Pages 489-495 ; 00920606 (ISSN) Atyabi, F ; Livari, M. A ; Kaviani, K ; Rahimi Tabar , M. R ; Sharif University of Technology
    In this paper we introduce two methods for measuring irregularities in human heartbeat time series (HHTS). First we consider the multi-fractal structure of HHTS to distinguish healthy individuals and from those with congestive heart failure. In this way we modify the Extended Self-Similarity (ESS) method and apply it to HHTS. Our second approach is based on the recursive method, which we use to predict the duration of the next heartbeat by considering a few previous ones. We use standard physiological data and show that these approaches lead to very satisfactory methods to resolve the healthy and CHF individuals. These methods can be used potentially in portable electronic heart alarm... 

    Simvastatin-loaded nano-niosomes confer cardioprotection against myocardial ischemia/reperfusion injury

    , Article Drug Delivery and Translational Research ; Volume 12, Issue 6 , 2022 , Pages 1423-1432 ; 2190393X (ISSN) Naseroleslami, M ; Mousavi Niri , N ; Akbarzade, I ; Sharifi, M ; Aboutaleb, N ; Sharif University of Technology
    Springer  2022
    Although simvastatin (SIM) has been proven to be a powerful agent against myocardial ischemia/reperfusion (MI/R) injury, poor water solubility, short half-life, and low bioavailability have made it futile while using conventional drug delivery system. Hence, this study aims to investigate therapeutic efficacy of SIM-loaded nano-niosomes on MI/R injury. Surface active agent film hydration method was used to synthesize nano-niosomes. The physicochemical properties of nano-niosomes were characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, niosomes were characterized in entrapment efficiency (EE) and releasing pattern. Male Wistar rats were...