Search for: mechanical-stimulation
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    Endothelial cells morphology in response to combined wss and biaxial cs: introduction of effective strain ratio

    , Article Cellular and Molecular Bioengineering ; Volume 13, Issue 6 , 2020 , Pages 647-657 Pakravan, H. A ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    Springer  2020
    Introduction: Endothelial cells (ECs) morphology strongly depends on the imposed mechanical stimuli. These mechanical stimuli include wall shear stress (WSS) and biaxial cyclic stretches (CS). Under combined loading, the effect of CS is not as simple as pure CS. The present study investigates the morphological response of ECs to the realistic mechanical stimuli. Methods: The cell population is theoretically studied using our previous validated model. The mechanical stimuli on ECs are described using four parameters; WSS magnitude (0 to 2.0 Pa), WSS angle (− 50° to 50°), and biaxial CS in two perpendicular directions (0 to 10%). The morphology of ECs is reported using four parameters; average... 

    Real-time simulation of the nonlinear visco-elastic deformations of soft tissues

    , Article International Journal of Computer Assisted Radiology and Surgery ; Volume 6, Issue 3 , 2011 , Pages 297-307 ; 18616410 (ISSN) Basafa, E ; Farahmand, F ; Sharif University of Technology
    Purpose: Mass-spring-damper (MSD) models are often used for real-time surgery simulation due to their fast response and fairly realistic deformation replication. An improved real time simulation model of soft tissue deformation due to a laparoscopic surgical indenter was developed and tested. Method: The mechanical realization of conventional MSD models was improved using nonlinear springs and nodal dampers, while their high computational efficiency was maintained using an adapted implicit integration algorithm. New practical algorithms for model parameter tuning, collision detection, and simulation were incorporated. Results: The model was able to replicate complex biological soft tissue... 

    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) Pakravan, H. A ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    Springer Verlag 
    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... 

    Stimuli-responsive chitosan as an advantageous platform for efficient delivery of bioactive agents

    , Article Journal of Controlled Release ; Volume 317 , 2020 , Pages 216-231 Sabourian, P ; Tavakolian, M ; Yazdani, H ; Frounchi, M ; van de Ven, T. G. M ; Maysinger, D ; Kakkar, A ; Sharif University of Technology
    Elsevier B.V  2020
    Despite a diverse range of active pharmaceutical agents currently at our disposal, high morbidity rate diseases continue to pose a major health crisis globally. One of the important parameters in this regard is the controlled cargo delivery at desired sites. Among a variety of synthetic and natural macromolecular systems, chitosan, an abundant biopolymer, offers a platform for tailored architectures that could have high loading capacity of cargo, target and deliver. Stimuli directed accumulation of vehicles and drug release is an area of direct relevance to biomedical applications. In this review, we highlight essential characteristics of modified chitosan that present themselves for... 

    A microfabricated platform for the study of chondrogenesis under different compressive loads

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 78 , 2018 , Pages 404-413 ; 17516161 (ISSN) Kowsari Esfahan, R ; Jahanbakhsh, A ; Saidi, M. S ; Bonakdar, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Microfluidic devices are beneficial in miniaturizing and multiplexing various cellular assays in a single platform. Chondrogenesis is known to pertain to chemical, topographical, and mechanical cues in the microenvironment. Mechanical cues themselves have numerous parameters such as strain magnitude, frequency, and stimulation time. Effects of different strain magnitudes on the chondrogenic differentiation of adult stem cells have not been explored thoroughly. Here, a new multilayer microdevice is presented for the unidirectional compressive stimulation of cells in a three-dimensional cell culture. Numerical simulations were performed to evaluate and optimize the design. Results showed a...