Search for: cytology
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    Graphene scaffolds in progressive nanotechnology/stem cell-based tissue engineering of the nervous system

    , Article Journal of Materials Chemistry B ; Volume 4, Issue 19 , 2016 , Pages 3169-3190 ; 20507518 (ISSN) Akhavan, O ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Although graphene/stem cell-based tissue engineering has recently emerged and has promisingly and progressively been utilized for developing one of the most effective regenerative nanomedicines, it suffers from low differentiation efficiency, low hybridization after transplantation and lack of appropriate scaffolds required in implantations without any degrading in functionality of the cells. In fact, recent studies have demonstrated that the unique properties of graphene can successfully resolve all of these challenges. Among various stem cells, neural stem cells (NSCs) and their neural differentiation on graphene have attracted a lot of interest, because graphene-based neuronal tissue... 

    Biodegradable polyurethane acrylate/HEMA-grafted nanodiamond composites with bone regenerative potential applications: Structure, mechanical properties and biocompatibility

    , Article RSC Advances ; Volume 6, Issue 11 , 2016 , Pages 8743-8755 ; 20462069 (ISSN) Alishiri, M ; Shojaei, A ; Abdekhodaie, M. J ; Sharif University of Technology
    Royal Society of Chemistry 
    The present study demonstrates HEMA-grafted nanodiamond (ND-HEMA)/acrylate-terminated polyurethane-acrylate diluents (APUA) composites as promising materials for bone implant applications. Neat APUA and APUA composites containing ND-HEMA at different loadings up to 2 wt% were prepared by an in situ polymerization method. Morphological analysis demonstrated that ND-HEMAs were actually in the form of tightly bound aggregates which led to formation of big agglomerates at a concentration of 2 wt%. It was also suggested that ND-HEMAs were preferentially localized in the continuous soft domain of APUA; however it interacted by both soft and hard domains. Moreover, ND-HEMAs caused considerable... 

    Unified model of brain tissue microstructure dynamically binds diffusion and osmosis with extracellular space geometry

    , Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 94, Issue 3 , 2016 ; 15393755 (ISSN) Yousefnezhad, M ; Fotouhi, M ; Vejdani, K ; Kamali Zare, P ; Sharif University of Technology
    American Physical Society  2016
    We present a universal model of brain tissue microstructure that dynamically links osmosis and diffusion with geometrical parameters of brain extracellular space (ECS). Our model robustly describes and predicts the nonlinear time dependency of tortuosity (λ=D/D∗) changes with very high precision in various media with uniform and nonuniform osmolarity distribution, as demonstrated by previously published experimental data (D = free diffusion coefficient, D∗ = effective diffusion coefficient). To construct this model, we first developed a multiscale technique for computationally effective modeling of osmolarity in the brain tissue. Osmolarity differences across cell membranes lead to changes... 

    Collaboration alignment in distributed interference management in uplink cellular systems

    , Article 2016 IEEE International Symposium on Information Theory, 10 July 2016 through 15 July 2016 ; Volume 2016-August , 2016 , Pages 1456-1460 ; 21578095 (ISSN) ; 9781509018062 (ISBN) Kananian, B ; Maddah Ali, M. A ; Shariatpanahi, S. P ; Khalaj, B. H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    We consider a cellular wireless system including several interfering multi-user multi-antenna uplink channels, where the base station of each cell has to locally recover the messages of its corresponding users. We use a linear Wyner model, where each base station experiences interference only from the users in the two neighboring cells. Each base station is connected to the two nearby base stations through a backhaul link. The objective is to achieve the maximum degrees of freedom per cell, with minimum aggregated load in the backhaul. We propose a successive cooperative alignment scheme, in which each base station forms backhaul messages by combining the previous received backhaul messages... 

    Multi-objective dynamic cell formation problem: A stochastic programming approach

    , Article Computers and Industrial Engineering ; Volume 98 , 2016 , Pages 323-332 ; 03608352 (ISSN) Zohrevand, A. M ; Rafiei, H ; Zohrevand, A. H ; Sharif University of Technology
    Elsevier Ltd 
    This paper addresses dynamic cell formation problem (DCFP) which has been explored vastly for several years. Although a considerable body of literature in this filed, two remarkable aspects have been significantly ignored so far, as uncertainty and human-related issues. In order to compensate such a shortage, this paper develops a bi-objective stochastic model. The first objective function of the developed model seeks to minimize total cost of machine procurement, machine relocation, inter-cell moves, overtime utilization, worker hiring/laying-off, and worker moves between cells; while the second objective function maximizes labor utilization of the cellular manufacturing system. In the... 

    Ion Channel Based Bio-Synthetic Modulator for Diffusive Molecular Communication

    , Article IEEE Transactions on Nanobioscience ; Volume 15, Issue 5 , 2016 , Pages 418-432 ; 15361241 (ISSN) Arjmandi, H ; Ahmadzadeh, A ; Schober, R ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    In diffusion-based molecular communication (DMC), a transmitter nanomachine is responsible for signal modulation. Thereby, the transmitter has to be able to control the release of the signaling molecules employed for representing the transmitted information. In nature, an important class of control mechanisms for releasing molecules from cells utilizes ion channels which are pore-forming proteins across the cell membrane. The opening and closing of the ion channels is controlled by a gating parameter. In this paper, an ion channel based modulator for DMC is proposed which controls the rate of molecule release from the transmitter by modulating a gating parameter signal. Exploiting the... 

    BLESS: A simple and efficient scheme for prolonging PCM lifetime

    , Article 53rd Annual ACM IEEE Design Automation Conference, DAC 2016, 5 June 2016 through 9 June 2016 ; Volume 05-09 , June-2016 , 2016 ; 0738100X (ISSN); 9781450342360 (ISBN) Asadinia, M ; Jalili, M ; Sarbazi Azad, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2016
    Limited endurance problem and low cell reliability are main challenges of phase change memory (PCM) as an alternative to DRAM. To further prolong the lifetime of a PCM device, there exist a number of techniques that can be grouped in two categories: 1) reducing the write rate to PCM cells, and 2) handling cell failures when faults occur. Our experiments confirm that during write operations, an extensive non-uniformity in bit ips is exhibited. To reduce this non-uniformity, we present byte-level shifting scheme (BLESS) which reduces write pressure over hot cells of blocks. Additionally, this shifting mechanism can be used for error recovery purpose by using the MLC capability of PCM and... 

    Preparation of biodegradable gelatin/PVA porous scaffolds for skin regeneration

    , Article Artificial Cells, Nanomedicine and Biotechnology ; 2016 , Pages 1-8 ; 21691401 (ISSN) Mahnama, H ; Dadbin, S ; Frounchi, M ; Rajabi, S ; Sharif University of Technology
    Taylor and Francis Ltd  2016
    Porous scaffolds composed of gelatin/poly (vinyl alcohol), (Gel/PVA), were prepared using combination of freeze gelation and freeze drying methods. The effect of polymer concentration, gelatin/PVA ratio, and glutaraldehyde/gelatin ratio (GA/Gel) was investigated on morphology of pores, swelling ratio, biodegradation, and skin cell culture. At optimum preparation conditions the scaffolds had uniform pore size distributions showing high swelling ratio of 23.6. The scaffolds were of biodegradable nature and almost degraded in 28 days. Human dermal fibroblast cells (HDF) were cultured on the scaffolds and MTS assay was conducted to evaluate the influence of PVA on growth and proliferation of the... 

    High antimicrobial activity and low human cell cytotoxicity of core-shell magnetic nanoparticles functionalized with an Antimicrobial Peptide

    , Article ACS Applied Materials and Interfaces ; Volume 8, Issue 18 , 2016 , Pages 11366-11378 ; 19448244 (ISSN) Maleki, H ; Rai, A ; Pinto, S ; Evangelista, M ; Cardoso, R. M. S ; Paulo, C ; Carvalheiro, T ; Paiva, A ; Imani, M ; Simchi, A ; Durães, L ; Portugal, A ; Ferreira, L ; Sharif University of Technology
    American Chemical Society  2016
    Superparamagnetic iron oxide nanoparticles (SPIONs) functionalized with antimicrobial agents are promising infection-targeted therapeutic platforms when coupled with external magnetic stimuli. These antimicrobial nanoparticles (NPs) may offer advantages in fighting intracellular pathogens as well as biomaterial-associated infections. This requires the development of NPs with high antimicrobial activity without interfering with the biology of mammalian cells. Here, we report the preparation of biocompatible antimicrobial SPION@gold core-shell NPs based on covalent immobilization of the antimicrobial peptide (AMP) cecropin melittin (CM) (the conjugate is named AMP-NP). The minimal inhibitory... 

    Investigation of readout cell configuration and parameters on functionality and stability of bi-directional RSFQ TFF

    , Article IEEE Transactions on Applied Superconductivity ; Volume 26, Issue 3 , 2016 ; 10518223 (ISSN) Jabbari, T ; Zandi, H ; Foroughi, F ; Bozbey, A ; Fardmanesh, M ; Sharif University of Technology
    Considering the two main categories of rapid single flux quantum gates with destructive and nondestructive readout process, we have investigated the effects of readout cell topology and involved critical parameters on the proper functionality and stability of the states of the newly developed bidirectional T flip-flops (TFFs). It is observed that instabilities and fluctuations in the state of the gate (memory of TFF) after each transition determine the minimum time intervals between the clock pulses set by the ac bias current, further limiting the ultimate operation frequency of the circuits. The absolute values of the current levels of the junctions at each state, which play an important... 

    A comparative study of collagen matrix density effect on endothelial sprout formation using experimental and computational approaches

    , Article Annals of Biomedical Engineering ; Volume 44, Issue 4 , 2016 , Pages 929-941 ; 00906964 (ISSN) Shamloo, A ; Mohammadaliha, N ; Heilshorn, S. C ; Bauer, A. L ; Sharif University of Technology
    A thorough understanding of determining factors in angiogenesis is a necessary step to control the development of new blood vessels. Extracellular matrix density is known to have a significant influence on cellular behaviors and consequently can regulate vessel formation. The utilization of experimental platforms in combination with numerical models can be a powerful method to explore the mechanisms of new capillary sprout formation. In this study, using an integrative method, the interplay between the matrix density and angiogenesis was investigated. Owing the fact that the extracellular matrix density is a global parameter that can affect other parameters such as pore size, stiffness,... 

    Development of a virtual cell model to predict cell response to substrate topography

    , Article ACS Nano ; Volume 11, Issue 9 , 2017 , Pages 9084-9092 ; 19360851 (ISSN) Heydari, T ; Heidari, M ; Mashinchian, O ; Wojcik, M ; Xu, K ; Dalby, M. J ; Mahmoudi, M ; Ejtehadi, M. R ; Sharif University of Technology
    Cells can sense and respond to changes in the topographical, chemical, and mechanical information in their environment. Engineered substrates are increasingly being developed that exploit these physical attributes to direct cell responses (most notably mesenchymal stem cells) and therefore control cell behavior toward desired applications. However, there are very few methods available for robust and accurate modeling that can predict cell behavior prior to experimental evaluations, and this typically means that many cell test iterations are needed to identify best material features. Here, we developed a unifying computational framework to create a multicomponent cell model, called the... 

    A numerical approach to study the post-yield softening in cellular solids: role of microstructural ordering and cell size distribution

    , Article Acta Mechanica ; Volume 228, Issue 6 , 2017 , Pages 2005-2016 ; 00015970 (ISSN) Goodarzi Hosseinabadi, H ; Bagheri, R ; Altstadt, V ; Sharif University of Technology
    Springer-Verlag Wien  2017
    Designing meta-materials and cellular solids with biomimetic structures has received increasing attention in the past few years partially due to advances in additive manufacturing techniques that have enabled the fabrication of advanced materials with arbitrarily complex microarchitectures and novel functionalities. To impact on this trend, it is essential to develop our understanding about the role of microstructure on mechanical responses of these structures. Although a large literature exists on the general subject, the role of microstructure on the post-yield instability is not yet adequately documented. This research introduces a numerical approach to study the post-yield instability in... 

    Dynamic analysis of magnetic nanoparticles crossing cell membrane

    , Article Journal of Magnetism and Magnetic Materials ; Volume 429 , 2017 , Pages 372-378 ; 03048853 (ISSN) Pedram, M. Z ; Shamloo, A ; Ghafar Zadeh, E ; Alasty, A ; Sharif University of Technology
    Elsevier B.V  2017
    Nowadays, nanoparticles (NPs) are used in a variety of biomedical applications including brain disease diagnostics and subsequent treatments. Among the various types of NPs, magnetic nanoparticles (MNPs) have been implemented by many research groups for an array of life science applications. In this paper, we studied MNPs controlled delivery into the endothelial cells using a magnetic field. Dynamics equations of MNPs were defined in the continuous domain using control theory methods and were applied to crossing the cell membrane. This study, dedicated to clinical and biomedical research applications, offers a guideline for the generation of a magnetic field required for the delivery of... 

    Biomechanical analysis of actin cytoskeleton function based on a spring network cell model

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 231, Issue 7 , 2017 , Pages 1308-1323 ; 09544062 (ISSN) Ghaffari, H ; Saidi, M. S ; Firoozabadi, B ; Sharif University of Technology
    SAGE Publications Ltd  2017
    In this study, a new method for the simulation of the time-dependent behavior of actin cytoskeleton during cell shape change is proposed. For this purpose, a three-dimensional model of endothelial cell consisting of cell membrane, nucleus membrane, and main components of cytoskeleton, namely actin filaments, microtubules, and intermediate filaments is utilized. Actin binding proteins, which play a key role in regulating actin cytoskeleton behavior, are also simulated by using a novel technique. The actin cytoskeleton in this model is more dynamic and adoptable during cell deformation in comparison to previous models. The proposed model is subjected to compressive force between parallel micro... 

    Integrated system of multiple batches to evaluate the continuous performance of microbial cells in decolourization processes

    , Article Journal of Environmental Chemical Engineering ; Volume 6, Issue 1 , February , 2018 , Pages 728-735 ; 22133437 (ISSN) Vatandoostarani, S ; Bagheri Lotfabad, T ; Heidarinasab, A ; Ebadipour, N ; Yaghmaei, S ; Sharif University of Technology
    Elsevier Ltd  2018
    Azo dye degradation in wastewater treatment is a subject which has garnered the attention of many research studies. In this study, an innovative approach, namely, an integrated system of five batches (ISFB), was developed to investigate the capability of Saccharomyces cerevisiae ATCC 9763 for continuous degradation of methyl red as a representative azo dye. Toward this end, an expanded immobilized microbial bed (EIMB) reactor was established with a bed of encapsulated yeast cells in sodium alginate. EIMB reactor was run in two modes, single batch and ISFB. Moreover, durability of the microbial cells was evaluated by repeating the continuous decolourization eight sequential times in EIMB at... 

    Neuro-Skins: Dynamics, plasticity and effect of neuron type and cell size on their response

    , Article Neural Processing Letters ; 2018 , Pages 1-23 ; 13704621 (ISSN) Joghataie, A ; Shafiei Dizaji, M ; Sharif University of Technology
    Springer New York LLC  2018
    We are introducing a new type of membrane, called neuro-skin or neuro-membrane. It is comprised of neurons embedded in a plastic membrane. The skin is smart and adaptive and is capable of providing desirable response to inputs intelligently. This way, the neuro-skin can be considered as a new type of neural network with adaptivity and learning capabilities. However, in this paper, only the response of neuro-skins to a dynamic input is studied. The membrane is modelled by nonlinear dynamic finite elements. Each finite element is considered as a cell of the neuro-skin which has a neuron. The neuron is the intelligent nucleus of the element. So, the finite elements are called finite... 

    A portable culture chamber for studying the effects of hydrostatic pressure on cellular monolayers

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; 2018 ; 09544062 (ISSN) Kiyoumarsioskouei, A ; Saidi, M ; Mosadegh, B ; Firoozabadi, B ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Hydrostatic pressure is one of the most fundamental and common mechanical stimuli in the body, playing a critical role in the homeostasis of all organ systems. Kidney function is affected by high blood pressure, namely hypertension, by the increased pressure acting on the glomerular capillary walls. This general effect of hypertension is diagnosed as a chronic disease, but underlying mechanistic causes are still not well understood. This paper reports a portable and adaptive device for studying the effects of hydrostatic pressure on a monolayer of cells. The fabricated device fits within a conventional incubation system and microscope. The effects of various pressures and durations were... 

    Express read in MLC phase change memories

    , Article ACM Transactions on Design Automation of Electronic Systems ; Volume 23, Issue 3 , February , 2018 ; 10844309 (ISSN) Jalili, M ; Sarbazi Azad, H ; Sharif University of Technology
    Association for Computing Machinery  2018
    In the era of big data, the capability of computer systems must be enhanced to support 2.5 quintillion byte/day data delivery. Among the components of a computer system, main memory has a great impact on overall system performance. DRAM technology has been used over the past four decades to build main memories. However, the scalability of DRAM technology has faced serious challenges. To keep pace with the ever-increasing demand for larger main memory, some new alternative technologies have been introduced. Phase change memory (PCM) is considered as one of such technologies for substituting DRAM. PCM offers some noteworthy properties such as low static power consumption, nonvolatility, and... 

    A hybrid model on severe plastic deformation of copper

    , Article Computational Materials Science ; Volume 44, Issue 4 , 2009 , Pages 1107-1115 ; 09270256 (ISSN) Hosseini, E ; Kazeminezhad, M ; Sharif University of Technology
    A hybrid model based on the flow function and dislocation cell structure model by considering the Taylor assumption is utilized to model the dislocation structure evolution, cell size and mechanical properties of OFHC in severe plastic deformation. Here, the ECAP is chosen as a process of severe plastic deformation. In this study, the model is modified by taking the value of cell size coefficient as a function of strain and considering two different values of dynamic recovery coefficients of cell walls and cell interiors. These modifications lead to achieve the more accurate modeling results. From the flow function the strain rate distribution are achieved and then using the model the...