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    The Effect of Electroporation on Ultrasund Signals

    , M.Sc. Thesis Sharif University of Technology Dashti, Ali (Author) ; Zahedi, Edmond (Supervisor)
    Abstract
    In this thesis, a cellular model of electroporation process and its detection by ultrasound signals is proposed. Electroporation is permeabilization of the cell membrane, caused by an external electric field. The resulted pores open cell’s membrane to large or hydrophilic molecules. The process of Electroporation has been used in Gene therapy and treatment of solid tumors. In this project, first we made a phantom of electroporated tissue and a phantom of normal tissue and then we simulated their responses to a linear array ultrasound transducer. By comparision of received signals from phantoms the probable effect of electroporation on ultrasound RF signals revealed. Results show up to 5 %... 

    Evaluation of Plasmid Transmission in Bacillus Subtilis by Cell Wall Modification

    , M.Sc. Thesis Sharif University of Technology Mohamadzadeh, Mohammad Sadegh (Author) ; Roosta Azad, Reza (Supervisor) ; Aghamollaei, Hossein (Supervisor)
    Abstract
    Today, almost all the country's needs in the field of industrial enzymes are met through imports. In this regard, much attention has been paid to the industrial production of various enzymes in the country. The production of recombinant proteins through strain engineering is one of the most important ways to meet this demand due to its many benefits. One of the most important microorganisms that is widely used in the enzyme industry is Bacillus subtilis. Due to its thick peptidoglycan wall, this gram-positive bacterium hardly accepts engineered carriers for genetic modification as hosts. The aim of this study was to evaluate the permeability of the wall and cell membrane of Bacillus subtilis... 

    Cellular model of electroporated tissue for ultrasound RF data analysis

    , Article 2009 International Conference on Advances in Computational Tools for Engineering Applications, ACTEA 2009, Beirut, 15 July 2009 through 17 July 2009 ; 2009 , Pages 652-655 ; 9781424438341 (ISBN) Dashti, A ; Zahedi, E ; National Instruments; MSC Software; Pro Mech ; Sharif University of Technology
    2009
    Abstract
    Electroporation is permeabilization of the cell membrane, caused by an external electric field. Because of minimal thermal effects and minimal disturbance caused to tissue vasculature electroporation is becoming one of the methods of choice in tumor therapy. There has been no report indicating that reversible electroporation can be detected by ultrasound. In this work a cellular model for monitoring the electroporation process b; ultrasound RF signals is proposed. The density of aqueous pores with different sizes was found by applying the asymptotic model of electroporation and Smoluchowski equation. The cellular model was send to an ultrasound simulation program where pores were modeled by... 

    Revealing electrical stresses acting on the surface of protoplast cells under electric field

    , Article European Journal of Mechanics, B/Fluids ; Volume 76 , 2019 , Pages 292-302 ; 09977546 (ISSN) Dastani, K ; Moghimi Zand, M ; Hadi, A ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    When cells exposed to an electric field, localized changes in the distribution of the electric field will be induced and these changes in turn lead to electrical stresses on cell surface. The electrical stresses play a key role in the cell membrane structural changes which leads to important phenomena like hydrophilic pores formation on the cell membrane resulting in the cell permeability. In this work, protoplast cell interaction with direct current (DC) electric field is investigated. The electrical stresses acted on the cell membrane in the presence of electric field are investigated numerically by a modified finite difference method, fast Immersed Interface Method (IIM). Exact solution...