Search for: electric-stimulation
0.006 seconds
Total 22 records

    Simultaneous triple joint movement fuzzy control in FES-assisted rowing exercise

    , Article 2012 19th Iranian Conference of Biomedical Engineering, ICBME 2012, 20 December 2012 through 21 December 2012 ; December , 2012 , Pages 66-70 ; 9781467331302 (ISBN) Zarei, M ; Jahed, M ; Mehravar, M ; Sharif University of Technology
    Fuzzy Control of rowing exercise using Functional Electrical Stimulation (FES) concerns ankle, knee and hip joints. Muscular Modeling for each joint may contain two groups of muscles, namely extension and flexion. In the proposed method, joint controllers provide electrical stimulation pulses to the appropriate muscle group based on the trajectory error and according to a prescribed pattern designed for rowing exercise. Results indicate that the simulated Fuzzy control of desired angles closely match the experimental values for prescribed joints. Moreover, the robustness of the controller in presence of external disturbance is examined and the results show that the tracking of each joint... 

    Development of a Control Algorithm for Functional Electrical Stimulation to Achieve Smooth Motion

    , M.Sc. Thesis Sharif University of Technology Ghaem Maghami, Horieh (Author) ; Behzadipour, Saeed (Supervisor)
    The use of functional electrical stimulation after spinal cord injury is one of the most effective ways to prevent muscle atrophy.” Enzymes construction set, torque output increases and improved fatigue resistance”.
    Functional electrical stimulation devices help in the operation of a muscle by applying a weak electrical current. This stimulation causes muscle contraction. In other words, it replaces the neural signals required to move the limb that cannot be produced due to causes such as spinal cord injury (SCI) orsecondary problems that arise after SCI.
    One of the drawbacks of using FES is jerky motions in the muscles and limps. Such movements are not only harmful, but results in... 

    Investigation of Biocompatibility and Biodegradability of Porous Chitosan Scaffold in Nerve Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Dabaghi, Mohammad Hossein (Author) ; Mashayekhan, Shohreh (Supervisor) ; Ramezani Saadat, Ahmad (Supervisor)
    Nerve repair plays a very prominent and significant role among the efforts that have been made to integrate the concepts of tissue engineering in strategies to repair almost all parts of the body. This is partly due to the complexity of the nervous anatomy system and its function as well as the inefficiency of conventional repair methods that are based on a component of biomaterials or cells alone. Studies show that electrical stimulation can enhance the nerve regeneration process; so the use of conducting polymers has attracted much attention for the construction of neural tissue engineering scaffolds. In this study, the electrical properties of neurons and the effects of electrical... 

    Design and Fabrication of Conductive Polymeric Nanocomposite Scaffolds for Nerve Tissue Engineering

    , Ph.D. Dissertation Sharif University of Technology Baniasadi, Hossein (Author) ; Ramezani Saadat, Ahmad (Supervisor)
    In the current study, design, fabrication, and characterization of a novel conductive nanocomposite scaffold for nerve tissue engineering applications is reported. For this purpose, the highly conductive polyaniline/graphene nanocomposite (PAG) was synthesized via emulsion polymerization, used for fabrication of conductive chitosan/gelatin/PAG scaffolds, and the effect of PAG amount on the various properties of scaffolds were investigated. The synthesized graphene, polyaniline, and PAG were characterized and the obtained results revealed that partially exfoliated graphene nanosheets and highly conductive PAG with a conductivity of about 12 S.cm-1 and 7 S.cm-1, respectively were obtained. The... 

    Role of Synchronous Sub-network in the Propagation of Synchronization to the Neuronal Population

    , M.Sc. Thesis Sharif University of Technology Naderi, Amir Mohammad (Author) ; Moghimi Araghi, Saman (Supervisor)
    Epilepsy is one of the most common non-communicable neurological disorders, characterized by recurrent seizure symptoms. Although much progress has been made in the diagnosis, control, and treatment of epilepsy in recent years, the exact mechanism of seizures, the specific method for early diagnosis of epilepsy and related syndromes, and definitive treatment for all patients are not yet known. In a type of seizure known as focal seizure, the electrical activity of neurons at the epilepsy focus synchronizes abnormally, and this synchronization can propagate to other regions of the brain in a process called secondary generalization, which finding a method for its prevention is our essential goal... 

    Adaptive optimal multi-critic based neuro-fuzzy control of MIMO human musculoskeletal arm model

    , Article Neurocomputing ; Volume 173 , 2016 , Pages 1529-1537 ; 09252312 (ISSN) Balaghi, M. H. E ; Vatankhah, R ; Broushaki, M ; Alasty, A ; Sharif University of Technology
    Human bodies use the electrical currents to make the muscles move. Disconnection of the electrical signals between the brain and the muscles as a result of spinal cord injuries, causes paralysis below the level of injury. Functional electrical stimulation (FES) is used to stimulate the peripheral nerves of the disabled limbs. The level of these electrical signals should be selected so that the desired tasks are done successfully. Applying the appropriate controller which can result a human like behaviour and the accomplishment of the desired tasks has become a significant research area. In this paper, the multi-input multi-output (MIMO) musculoskeletal model of human arm with six muscles is... 

    Fabricating Graphene Paper and Determining Its Electrical and Mechanical Properties and Using It for Proliferation and Differentiation of Neural Stem Cells

    , M.Sc. Thesis Sharif University of Technology Akbar Shirazian, Soheil (Author) ; Akhavan, Omid (Supervisor)
    Nowadays, tissue engineering and stem cells-based therapies have outlined a promising prospect in neural networks regeneration. But it usually requires biocompatible and conductive scaffolds for culturing neural stem cells and directing their differentiation toward the neurons. Graphene due to its unique physical and chemical properties has attracted much interest in tissue engineering. For this purpose, in this study biocompatible graphene oxide foams have been used for neural stem cell culturing. For the first time, graphene oxide foam were fabricated by precipitation of chemically exfoliated graphene oxide sheets in an aqueous suspension onto the PET substrate at ~80 oC under UV... 

    Design a Model Predictive Control System for Empowerment and Rehabilitation of a Lower Limb Exoskeleton

    , M.Sc. Thesis Sharif University of Technology Farghadani, Sahand (Author) ; Vosoughi, Gholamreza (Supervisor)
    With the development of technology in the field of control, biomechanics and robotics, wearable robots have found many applications in the field of rehabilitation and empowerment. In the empowerment phase, due to the interaction of these robots with humans, it is necessary to manage the interaction forces between the robot and humans with the help of appropriate control methods. One of the applications of these robots is when a person wants to carry a heavy load attached to the structure of the robot and the robot should be able to transfer the force caused by this load to the ground. At this time, humans should not be exposed to this load and the relationship between the robot and humans... 

    Design and Implementation of a FES-Assisted Control for a Lower Limb Hybrid Exoskeleton Robot in order to Reduce the Robot Energy Consumption

    , M.Sc. Thesis Sharif University of Technology Karami, Mohammad (Author) ; Vosoughi, Gholamreza (Supervisor) ; Moradi, Hamed (Supervisor)
    Wearable robots, or exoskeletons, are electromechanical devices that aim to assist user by supplying additional mechanical power as needed. The interaction of these robots with humans and the possibility of robots using their various abilities such as intelligence, control power, sensors, etc., make one of the crucial components of these control algorithms, its interaction and integration with the user. In this regard, functional electrical stimulation is one way to use human abilities to control the robot and achieve broader goals. Adding functional electrical stimulation to a wearable robot creates an emerging group of robots called hybrid exoskeletons. Hybrid exoskeletons provide the... 

    Design, fabrication, and characterization of novel porous conductive scaffolds for nerve tissue engineering

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 64, Issue 18 , 2015 , Pages 969-977 ; 00914037 (ISSN) Baniasadi, H ; Ahmad Ramazani, S. A ; Mashayekhan, S ; Farani, M. R ; Ghaderinezhad, F ; Dabaghi, M ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Highly conductive polypyrrole/graphene (PYG) nanocomposite was synthesized with chemical oxidation process via emulsion polymerization and used for the preparation of novel porous conductive gelatin/chitosan-based scaffolds. The effect of PYG loading on various properties of scaffolds was investigated. The obtained results indicated that by introducing PYG into the polymeric matrix, the porosity and swelling capacity decreased while electrical conductivity and Young's modulus demonstrated increasing trend. The in vitro biodegradation test revealed that pure gelatin/chitosan matrix lost 80% of its weight after six weeks in the presence of lysozyme whilst the biodegradation rate was... 

    Rolled graphene oxide foams as three-dimensional scaffolds for growth of neural fibers using electrical stimulation of stem cells

    , Article Carbon ; Volume 97 , 2016 , Pages 71-77 ; 00086223 (ISSN) Akhavan, O ; Ghaderi, E ; Shirazian, S. A ; Rahighi, R ; Sharif University of Technology
    Elsevier Ltd 
    Graphene oxide foam (GOF) layers with thicknesses of ∼15-50 μm and density of ∼10 graphene oxide (GO) sheets/μm were fabricated by precipitation of chemically exfoliated GO sheets in an aqueous suspension at ∼80 °C under UV irradiation. Then, rolled GOFs with desirable scales were developed as electrically conductive 3D-scaffolds and applied in directional growth of neural fibers, through differentiation of human neural stem cells (hNSCs) into neurons under an electrical stimulation. X-ray photoelectron spectroscopy indicated that the UV irradiation resulted in partial deoxygenation of the layers. Scanning electron microscopy and Raman spectroscopy confirmed the presence of multilayer GO... 

    Effect of current density on electrochemical phosphating of stainless steel 316L

    , Article TMS 2009 - 138th Annual Meeting and Exhibition, San Francisco, CA, 15 February 2009 through 19 February 2009 ; Volume 3 , 2009 , Pages 613-620 ; 9780873397407 (ISBN) Oskuie, A. A ; Afshar, A ; Sharif University of Technology
    In this study two cation coating of calcium and zinc has been developed on stainless steel 316L by electrochemical method. Cathodic current used as an accelerator for phosphating process and the effects of current density on microstructure of the phospahted layer and the time needed for termination of the phosphating process has been evaluated by potential-time, SEM, EDS, etc. Results indicate that higher current densities in electrochemical phosphating will result in heavier phospahted layer with finer crystal size which in turn deteriorates the quality of the layer by its higher porosity. Chemical analysis of the layer reveals that using the electrochemical method for phosphating of... 

    Combined effects of electric stimulation and microgrooves in cardiac tissue-on-a-chip for drug screening

    , Article Small Methods ; Volume 4, Issue 10 , 2020 Ren, L ; Zhou, X ; Nasiri, R ; Fang, J ; Jiang, X ; Wang, C ; Qu, M ; Ling, H ; Chen, Y ; Xue, Y ; Hartel, M.C ; Tebon, P ; Zhang, S ; Kim, H.-J ; Yuan, X ; Shamloo, A ; Dokmeci, M. R ; Li, S ; Khademhosseini, A ; Ahadian, S ; Sun, W ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Animal models and traditional cell cultures are essential tools for drug development. However, these platforms can show striking discrepancies in efficacy and side effects when compared to human trials. These differences can lengthen the drug development process and even lead to drug withdrawal from the market. The establishment of preclinical drug screening platforms that have higher relevancy to physiological conditions is desirable to facilitate drug development. Here, a heart-on-a-chip platform, incorporating microgrooves and electrical pulse stimulations to recapitulate the well-aligned structure and synchronous beating of cardiomyocytes (CMs) for drug screening, is reported. Each chip... 

    Introducing a suitable Controller for Rowing Activity in Patients with Spinal CordInjuries using FES

    , M.Sc. Thesis Sharif University of Technology Zarei, Mohammad (Author) ; Jahed, Mehran (Supervisor)
    Disconnections in neural paths from the central nervous system to the muscles or vice versa cause different neuropathies, thus paralysis in different limbs may occur. As a result of the lack of muscular activity and the decrease in blood perfusion in paralyzed limbs, problems like osteoporosis, increase in the risk of breaking, decline in muscle size, cardiovascular diseases, renal dysfunction, bedsores, etc may happen. In order to induce movement in paralyzed limbs, thus preventingmentioned problems, rowing exercise through Functional Electrical Stimulation (FES) may be utilized. In FES, electrical Stimulation using current stimulating pulses is applied to contracting and relaxing muscles,... 

    Bohmian Quantum Approach to Mind, Brain, and Machine Interface

    , Ph.D. Dissertation Sharif University of Technology Jamali, Mohammad (Author) ; Golshani, Mehdi (Supervisor)
    The relation of mind and brain has always been a fundamental and challenging problem for science. The study of this subject with the help of modern physics, considering the failure of classical physics and materialistic philosophy in explaining spiritual and mental phenomena, has attracted the attention of contemporary eminent physicist and biologists. This area is known as "quantum consciousness" and involves theories about mind and brain. Among these theories are: Eccles-Beck theory, Heisenberg-James theory (presented by Stapp) and Penrose-Hameroff theory. In dealing with the problem of mind-matter interaction and consciousness, modern physics, psychology and some philosophical schools are... 

    Design and Implementation of an Intelligent Control System Based-on Deep Reinforcement Learning for a Lower-limb Hybrid Exoskeleton Robot

    , M.Sc. Thesis Sharif University of Technology Koushki, Amir Reza (Author) ; Vossoughi, Gholamreza (Supervisor) ; Boroushaki, Mehrdad (Supervisor)
    Hybrid Exoskeletons refer to simultaneous use of wearable robots and functional electrical stimulation technology. Hybrid exoskeletons have many advantages compared to the separate application of each of these technologies, such as reducing the robot’s energy consumption and the need for lighter and cheaper actuators for the robot, using humans muscle power, and reducing muscle fatigue. As a result, these robots have recently attracted a lot of interest in rehabilitation applications for patients suffering from mobility impairment.Control in hybrid exoskeletons is more complicated than control in traditional exoskeletons. Because in addition to robot and functional electrical stimulation... 

    Model Based Analysis of tDCS Effects on Brain Networks in Methamphetamine Addicts

    , M.Sc. Thesis Sharif University of Technology Hariri, Ali (Author) ; Fatemizadeh, Emadodin (Supervisor) ; Ekhtiari, Hamed (Co-Advisor)
    Despite intensive scientific investigations, drug addiction treatment outcomes have not significantly improved in more than 30 years. The addicted human brain can be conceptualized as a set of networks that spatially and temporally interact with each other in an abnormal way. Over the past several decades, neuroimaging techniques have contributed important novel insights into the neuroplastic alterations that result from drug dependence. Also functional connectivity magnetic resonance imaging (fcMRI) has emerged as a powerful tool for mapping large-scale networks in the human brain. On the other hand, transcranial direct current stimulation (tDCS) has been reintroduced as a noninvasive brain... 

    Evaluation and Analysis of tDCS and tACS in Improvement of Tinnitus Condition

    , M.Sc. Thesis Sharif University of Technology Tajari, Ahmad Reza (Author) ; Jahed, Mehran (Supervisor) ; Hani Tabatabaie, Mozhgan (Co-Supervisor) ; Asadpour, Abdureza (Co-Supervisor)
    Tinnitus is variety of sounds heard when no corresponding external sound is present. To remedy this condition, various methods have been proposed, however none have resulted in systematic and lasting results. This study aims to investigate the efficacy of non-invasive electrical stimulation techniques (tES) in the treatment of tinnitus. Stimulation parameters, including intensity, frequency, duration, and session frequency, are tailored to the individual's subjective tinnitus characteristics and treatment goals. Specifically, transcranial direct current stimulation (tDCS) is explored as a non-invasive method of electrical stimulation. In the tDCS method, electrodes are strategically... 

    Formation of Zn-Ca-Ni tri cation's phosphate coating on steel and study that properties

    , Article TMS 2009 - 138th Annual Meeting and Exhibition, San Francisco, CA, 15 February 2009 through 19 February 2009 ; Volume 1 , 2009 , Pages 615-623 ; 9780873397384 (ISBN) Zarei, M ; Afshar, A ; Sharif University of Technology
    A new Zinc phosphating bath, which produces coatings at relatively lower temperatures within a reasonable time by using of chemical accelerators has been devised. Improvement of the bath performance by the addition of divalent cations like calcium, nickel has been studied. Bath formulation and operating conditions have been optimized by coating weight determinations. Stable samples of phosphating formulations with and without calcium and nickel salts were prepared and the structure and morphology of the phosphate coatings were determined by using X-ray diffraction (XRD) techniques, scanning electron microscopy. ASTMB117 salt spray test and electrochemical impedance spectroscopy (EIS) were... 

    Two-dimensional model of melt flows and interface instability in aluminum reduction cells

    , Article Light Metals 2008, New Orleans, LA, 9 March 2008 through 13 March 2008 ; 2008 , Pages 443-448 ; 01470809 (ISSN); 9780873397100 (ISBN) Kadkhodabeigi, M ; Sharif University of Technology
    We derive a new non-linear two dimensional model for melt flows and interface instability in aluminum reduction cells. This model is based on non-linear de St. Venant shallow water equations and contains the main features of an aluminum reduction cell. In this model we consider linear friction terms but in a new way that has not been considered in previous works. Our results are in good agreement with the results of simulation of viscous flow. This model is applicable both in determination of melt flows in molten aluminum and cryolite layers and also in finding the extreme limit for stability of interfacial waves in an aluminum reduction cell