Search for: human-skin
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    Numerical Investigation of Non-Fourier Heat Conduction in Human Skin

    , M.Sc. Thesis Sharif University of Technology Hodjat, Reza (Author) ; Taghizade Manzari, Merdad (Supervisor) ; Sani Joushaghani, Mahdi (Supervisor)
    When classical Fourier law of heat conduction is not applicable due to finite speed of heat propagation in a medium, non-Fourier heat conduction is used. In non-Fourier heat conduction, heat transfer is studied considering finite speed of heat flux (thermal wave) or temperature gradient or both (dual phase lag). Biological tissues like skin are one of the materials which show non-Fourier behavior during usual heating processes. In this research heat transfer in human skin is modeled by Fourier, thermal wave and dual phase lag (DPL) models. The equations are solved using the finite difference method and the temperature distribution across the tissue is calculated. In thermal wave model,... 

    Simulation and Assessment of Millimeter-Wave Reflectometry for Detection of Skin Cancers

    , M.Sc. Thesis Sharif University of Technology Aminzadeh, Reza (Author) ; Shishegar, Amir Ahmad (Supervisor)
    The goal of the research presented in this thesis is assessment of millimeter-wave (mm-wave) reflectometry as a potential method for non-invasive detection of skin cancers. The reasons for choosing mm-waves are lower penetration, higher resolution and technology maturity. The main work of this research is numerical simulation of reflection from skin and other media as well as reflection measurement of some skin-equivalent phantoms at mm-wave frequencies. By exposing the skin to mm-waves and studying the characteristics of the reflected wave malignant lesions are differentiated from benign and normal skin tissues. Since Oxygen molecules have strong attenuation peaks around 60 GHz band, this... 

    Numerical Solution Of One-Dimensional Non-Fourier Bioheat Transfer Through Skin Tissue

    , M.Sc. Thesis Sharif University of Technology Fazel, Zeynab (Author) ; Taghizadeh Manzari, Mehrdad (Supervisor)
    Innovations in laser, microwaves, and similar technologies have significantly advanced thermal treatments for diseases or even injuries concerning skin tissue. For a thorough understanding in the underlying mechanisms of bioheat transfer behavior of skin,a1D unsteady non-dimensional hyperbolic model of heat transfer through this tissue with metabolic heat generation which is subject to specific boundary conditions, is solved numerically using the finite difference method. A thermal shock is generated at the base of the tissue, which moves forward with a finite speed. A Numerical solution for a simple one-layer skin tissue is obtained. Then, the effects of various parameters, time step,... 

    Investigation of human skin collagen distribution in response to polarized laser by ellipsometry

    , Article Proceedings of the 6th IASTED International Conference on Biomedical Engineering, BioMED 2008, 13 February 2008 through 15 February 2008, Innsbruck ; 2008 , Pages 307-312 ; 9780889867215 (ISBN) Fattahi, H ; Tahvildari, R ; Amjadi, A ; Nejhad, M. B ; Sharif University of Technology
    The important role of collagen fibers in LILT has been observed. However there is still unclear information about light characteristics, such as coherence and polarization. Collagens behavior in response to different polarization is presented in this study. We investigate the distribution and structure of collagen bundles in full-thickness human skin in response to laser with different polarization by ellipsometry technique. For this study, we chose skin from the back part of a white man. The light source is HeNe laser. Samples are irradiated by three different polarizations. Sample S is irradiated using the electric field vector of the polarized laser radiation aligned in parallel with the... 

    Porous gelatin/poly(ethylene glycol) scaffolds for skin cells

    , Article Soft Materials ; Volume 15, Issue 1 , 2017 , Pages 95-102 ; 1539445X (ISSN) Vahidi, M ; Frounchi, M ; Dadbin, S ; Sharif University of Technology
    Biocompatible porous polymeric scaffolds provide a suitable environment for proliferation of stem cells in human body. In this research work, porous gelatin–poly(ethylene glycol), PEG, based scaffolds were prepared using combination of freeze-gelation and freeze-extraction methods. Effects of various parameters such as freezing temperature, cross-linking agent, concentrations of gelatin and PEG and their blending ratio on physical and mechanical properties, swelling ratio, porosity, pore size, and degradation rate of scaffolds were investigated. Also, proliferation of fibroblast skin cells on the scaffolds was examined by MTS assay to assess the suitability of the scaffolds in wound healing... 

    Noise reduction in OCT skin images

    , Article Progress in Biomedical Optics and Imaging - Proceedings of SPIE, 12 February 2017 through 14 February 2017 ; Volume 10137 , 2017 ; 16057422 (ISSN) ; 9781510607194 (ISBN) Turani, Z ; Fatemizadeh, E ; Adabi, S ; Mehregan, D ; Daveluy, S ; Nasiriavanaki, M ; Gimi, B ; Krol, A ; Sharif University of Technology
    OCT skin images suffer from artifacts. Speckle is the main artifact while the other one is called background noise. In this study, we propose an algorithm that significantly reduces the background noise before applying a speckle reduction method. The results show that the diagnostically relevant features in the images become clearer after applying the proposed method. We used sub-pixel weighted median filtering for speckle reduction. The results from background noise removal in combination with the proposed speckle reduction algorithm show a significant improvement in the clarity of diagnostically relevant features in in-vivo human skin images. © 2017 SPIE  

    In vitro co-culture of human skin keratinocytes and fibroblasts on a biocompatible and biodegradable scaffold

    , Article Iranian Biomedical Journal ; Volume 13, Issue 3 , 2009 , Pages 169-177 ; 1028852X (ISSN) Shariati, S. R. P ; Shokrgozar, M. A ; Vossoughi, M ; Eslamifar, A ; Sharif University of Technology
    Background: Extensive full-thickness burns require replacement of both epidermis and dermis. In designing skin replacements, the goal has been to re-create this model and make a product which has both essential components. Methods: In the present study, we developed procedures for establishing confluent, stratified layers of cultured human keratinocytes on the surface of modified collagen-chitosan scaffold that contains fibroblasts. The culture methods for propagation of keratinocytes and fibroblasts isolated from human neonatal foreskin were developed. The growth and proliferation of normal human keratinocytes were evaluated in serum-free (keratinocyte growth medium) and our modified... 

    Temporary skin grafts based on hybrid graphene oxide-natural biopolymer nanofibers as effective wound healing substitutes: pre-clinical and pathological studies in animal models

    , Article Journal of Materials Science: Materials in Medicine ; Volume 28, Issue 5 , 2017 , 73 ; 09574530 (ISSN) Mahmoudi, N ; Eslahi, N ; Mehdipour, A ; Mohammadi, M ; Akbari, M ; Samadikuchaksaraei, A ; Simchi, A ; Sharif University of Technology
    Springer New York LLC  2017
    Abstract: In recent years, temporary skin grafts (TSG) based on natural biopolymers modified with carbon nanostructures have received considerable attention for wound healing. Developments are required to improve physico-mechanical properties of these materials to match to natural skins. Additionally, in-deep pre-clinical examinations are necessary to ensure biological performance and toxicity effect in vivo. In the present work, we show superior acute-wound healing effect of graphene oxide nanosheets embedded in ultrafine biopolymer fibers (60 nm) on adult male rats. Nano-fibrous chitosan-based skin grafts crosslinked by Genepin with physico-mechanical properties close to natural skins were...