Search for: physiology
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    Epidemiology and patho-physiological studies in trypanosoma evansi infected camels and buffaloes in Pakistan

    , Article Pakistan Journal of Agricultural Sciences ; Volume 58, Issue 2 , 2021 , Pages 711-718 ; 05529034 (ISSN) Hussain, R ; Mehmood, K ; Abbas, R. Z ; Khan, I ; Siddique, A. B ; Masood, S ; Qadir, M.S ; Ishaq, H. M ; Akram, R ; Ghori, M.T ; Khan, A ; Tayyib, M ; Sharif University of Technology
    University of Agriculture  2021
    This study describes some epidemiological and patho-physiological aspects of Trypanosoma evansi (causative agent of “surra”) infection in camels (n=255) and Nili Ravi buffaloes (n=233). Clinical ailments like fever, shivering, edema of pads and urticarial swelling were observed in infected animals. Overall prevalence of T. evansi infection in buffaloes was 9.01 and 15.12% based on blood smear examination and PCR, respectively, while in camels, the prevalence was 10.58 and 15.29% based on smear examination and PCR, respectively. Results on epidemiological data did not indicate significant association of different factors of hosts with prevalence of T. evansi. Hematological parameters... 

    Effect of input voltage frequency on the distribution of electrical stresses on the cell surface based on single-cell dielectrophoresis analysis

    , Article Scientific Reports ; Volume 10, Issue 1 , 2020 Dastani, K ; Moghimi Zand, M ; Kavand, H ; Javidi, R ; Hadi, A ; Valadkhani, Z ; Renaud, P ; Sharif University of Technology
    Nature Research  2020
    Electroporation is defined as cell membrane permeabilization under the application of electric fields. The mechanism of hydrophilic pore formation is not yet well understood. When cells are exposed to electric fields, electrical stresses act on their surfaces. These electrical stresses play a crucial role in cell membrane structural changes, which lead to cell permeabilization. These electrical stresses depend on the dielectric properties of the cell, buffer solution, and the applied electric field characteristics. In the current study, the effect of electric field frequency on the electrical stresses distribution on the cell surface and cell deformation is numerically and experimentally... 

    Cuff-less high-accuracy calibration-free blood pressure estimation using pulse transit time

    , Article Proceedings - IEEE International Symposium on Circuits and Systems, 24 May 2015 through 27 May 2015 ; Volume 2015-July , 2015 , Pages 1006-1009 ; 02714310 (ISSN) ; 9781479983919 (ISBN) Kachuee, M ; Kiani, M.M ; Mohammadzade, H ; Shabany, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Recently a few methods have been proposed in the literature for non-invasive cuff-less estimation of systolic and diastolic blood pressures. One of the most prominent methods is to use the Pulse Transit Time (PTT). Although it is proven that PTT has a strong correlation with the systolic and diastolic blood pressures, this relation is highly dependent to each individuals physiological properties. Therefore, it requires per person calibration for accurate and reliable blood pressure estimation from PTT, which is a big drawback. To alleviate this issue, in this paper, a novel method is proposed for accurate and reliable estimation of blood pressure that is calibration-free. This goal is... 

    Physiological and psychological neural system modeling for a key-pressing test

    , Article Proceedings of the IASTED International Conference on Biomedical Engineering, Salzburg, 25 June 2003 through 27 June 2003 ; 2003 , Pages 66-70 ; 0889863539 (ISBN) Mahmudi, H ; Shahdi, S. A ; Vahdat, B. V ; IASTED ; Sharif University of Technology
    The model introduced in this article for neural system describes both physiological and psychological concepts of neural system and is based on the models of individual elements of the system. This model includes psychological characteristics such as; perception, prediction, learning and response planning, and physiological features such as; sensory analysis, memory and motor execution. The model is designed in such a way that it describes the performance of the neural system for a key-pressing test. The key-pressing experiment consists of a screen with numbers from 1 to 9, which is shown to the operator where one of the numbers is specified by a special color and the operator is to push the... 

    Parameter estimation of a mathematical model describing the cardiovascular-respiratory interaction

    , Article Computing in Cardiology, 6 September 2015 through 9 September 2015 ; Volume 42 , 2015 , Pages 617-620 ; 23258861 (ISSN) ; 9781509006854 (ISBN) Goldoozian, L. S ; Hidalgo Muñoz, A. R ; Zarzoso, V ; Zahedi, E ; Murray A ; Sharif University of Technology
    IEEE Computer Society  2015
    Short-term interaction between heart rate (HR) and physiological measures like blood pressure and respiration reveals relevant information about autonomic nervous system (ANS) function. Complex mathematical models for describing their couplings have been proposed in the literature. However, an accurate estimation of their parameters in an inverse modeling problem is crucial to extract reliable ANS related indices. This study considers a physiologically-based model of the cardiovascular-respiratory system and ANS control that presents the neural and mechanical effects of respiration separately. The estimation method is evaluated on synthetic signals. An accurate estimation of the... 

    A Physiological model-based study of flow-mediated dilation in peripheral arteries using finger photoplethysmogram signal

    , Article 2017 24th Iranian Conference on Biomedical Engineering and 2017 2nd International Iranian Conference on Biomedical Engineering, ICBME 2017, 30 November 2017 through 1 December 2017 ; 2018 ; 9781538636091 (ISBN) Habib Parsafar, M ; Zahedi, E ; Vosoughi Vahdat, B ; Sharif University of Technology
    Flow-mediated dilation measurement in the brachial artery using ultrasound imaging (FMD-US) is a common noninvasive procedure for endothelial function evaluation in the peripheral arteries. As FMD-US is operator-dependent and involves onerous equipment, its use has been mostly confined to research settings. In this paper, we propose to use the more accessible finger photoplethysmogram signal in conjunction with the FMD test (FMD-PPG) as a surrogate method. To this end, a tube-load physiological model of the upper arterial path in the arm is developed. Signals acquired from young and elderly subjects (N=20) are then investigated using model parameter estimation by the genetic algorithm. Our... 

    Mechanical characteristics of SPG-178 hydrogels: Optimizing viscoelastic properties through microrheology and response surface methodology

    , Article Iranian Biomedical Journal ; Volume 24, Issue 2 , 2020 , Pages 110-118 Seyedkarimi, M. S ; Mirzadeh, H ; Mohammadi, A ; Bagheri Khoulenjani, S ; Sharif University of Technology
    Pasteur Institute of Iran  2020
    Background: SApeptides have growing applications in tissue engineering and regenerative medicine. The application of SApeptide-based hydrogels depends strongly on their viscoelastic properties. Optimizing the properties is of importance in tuning the characteristics of the hydrogels for a variety of applications. Methods: In this study, we employed statistical modeling, conducted with the RSM and particle tracking microrheology, to investigate the effects of self-assembling SPG-178 peptide and added NaCl salt concentrations and milieu type (DI water or blood serum) on the viscoelastic properties of SPG-178 hydrogels. A central composite RSM model was employed for finding the optimum value of... 

    Stress softening and permanent deformation in human aortas: Continuum and computational modeling with application to arterial clamping

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 61 , 2016 , Pages 600-616 ; 17516161 (ISSN) Fereidoonnezhad, B ; Naghdabadi, R ; Holzapfel, G. A ; Sharif University of Technology
    Elsevier Ltd  2016
    Inelastic phenomena such as stress softening and unrecoverable inelastic deformations induced by supra-physiological loading have been observed experimentally in soft tissues such as arteries. These phenomena need to be accounted for in constitutive models of arterial tissues so that computational models can properly predict the outcome of interventional procedures such as arterial clamping and balloon angioplasty that involve non-physiological tissue loading. Motivated by experimental data, a novel pseudo-elastic damage model is proposed to describe discontinuous softening and permanent deformation in arterial tissues. The model is fitted to experimental data and specific material... 

    Design and development of a hand robotic rehabilitation device for post stroke patients

    , Article Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference ; 2009 , Pages 5026-5029 ; 1557170X (ISSN) Rashedi, E ; Mirbagheri, A ; Taheri, B ; Farahmand, F ; Vossoughi, G. R ; Parnianpour, M ; Sharif University of Technology
    Robot-mediated rehabilitation is a rapidly advancing discipline that seeks to develop improved treatment procedures using new technologies, e.g., robotics, coupled with modern theories in neuroscience and rehabilitation. A robotic device was designed and developed for rehabilitation of upper limbs of post stroke patients. A novel force feedback bimanual working mode provided real-time dynamic sensation of the paretic hand. Results of the preliminary clinical tests revealed a quantitative evaluation of the patient's level of paresis and disability  

    Hyperthermia-induced protein corona improves the therapeutic effects of zinc ferrite spinel-graphene sheets against cancer

    , Article RSC Advances ; Vol. 4, issue. 107 , 2014 , p. 62557-62565 Hajipour, M. J ; Akhavan, O ; Meidanchi, A ; Laurent, S ; Mahmoudi, M ; Sharif University of Technology
    Superparamagnetic zinc ferrite spinel-graphene nanostructures were synthesized as potential therapeutic agents in the magnetic targeted photothermal therapy of cancer and/or drug delivery. The global temperature of the solution and the local temperature at the nanoparticle (NP) surface determine the protein corona composition/content, which in turn affects the biological effects of NPs and the corresponding physiological responses. Therefore, it is rational to hypothesize that spinel-graphene nanostructures may have distinct protein corona compositions and contents, and therapeutic and toxic effects under laser irradiation. To assess this hypothesis, the effects of laser irradiation on the... 

    Physiological temperature has a crucial role in amyloid beta in the absence and presence of hydrophobic and hydrophilic nanoparticles

    , Article ACS Chemical Neuroscience ; Volume 4, Issue 3 , December , 2013 , Pages 375-378 ; 19487193 (ISSN) Ghavami, M ; Rezaei, M ; Ejtehadi, R ; Lotfi, M ; Shokrgozar, M. A ; Abd Emamy, B ; Raush, J ; Mahmoudi, M ; Sharif University of Technology
    Amyloid beta fibrillation can lead to major disorder of neurons processes and is associated with several neuronal diseases (e.g., Alzheimer's disease). We report here an importance of slight temperature changes, in the physiological range (35-42 °C), on the amyloid fibrillation process in the presence and absence of hydrophilic (silica) and hydrophobic (polystyrene) nanoparticles (NPs). The results highlight the fact that slight increases in temperature can induce inhibitory and acceleratory effects of hydrophobic and hydrophilic NPs on the fibrillation process, respectively. Using further in vivo considerations, the outcomes of this study can be used for considerable modifications on the... 

    Variations in trunk muscle activities and spinal loads following posterior lumbar surgery: A combined in vivo and modeling investigation

    , Article Clinical Biomechanics ; Volume 30, Issue 10 , 2015 , Pages 1036-1042 ; 02680033 (ISSN) Jamshidnejad, S ; Arjmand, N ; Sharif University of Technology
    Background Iatrogenic injuries to paraspinal muscles during posterior lumbar surgery cause a reduction in their contractile cross-sectional area and thus presumably their postoperative activation. This study investigates the effect of such intraoperative injuries on postoperative patterns of muscle activations and spinal loads during various activities using a combined modeling and in vivo MR imaging approach. Methods A three-dimensional, multi-joint, musculoskeletal model was used to estimate pre- and postoperative muscle forces and spinal loads under various activities in upright and flexed postures. According to our in vivo pre- and postoperative (∼ 6 months) measurements in six patients... 

    Selection and simulation of a proper microfluidic for hepatocyte culture

    , Article 2015 22nd Iranian Conference on Biomedical Engineering, ICBME 2015, 25 November 2015 through 28 November 2015 ; 2015 , Pages 65-69 ; 9781467393515 (ISBN) Nejadnasrollah, F ; Firoozabadi, B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    The advent of microfluidics as suitable environments for culturing cells is associated with some challenges as shear stresses applied on the cells. Moreover, among all factors needed for cell viability, feeding hepatocytes with adequate oxygen is of great importance due to their high demand for oxygen compared the other cell types. In this paper three kinds of geometries has been studied in order that shear stresses would be in allowed range and provision of hepatocytes with sufficient oxygen concentrations has been ensured as well. In addition to supplying hepatocytes with oxygen, the range of its concentration has been adjusted in physiologic value so that it would be practical for further... 

    MEG based classification of wrist movement

    , Article Proceedings of the 31st Annual International Conference of the IEEE Engineering in Medicine and Biology Society: Engineering the Future of Biomedicine, EMBC 2009 ; 2009 , Pages 986-989 ; 1557170X (ISSN) ; 978-142443296-7 (ISBN) Montazeri, N ; Shamsollahi, M. B ; Hajipour, S ; Sharif University of Technology
    Neural activity is very important source for data mining and can be used as a control signal for brain-computer interfaces (BCIs). Particularly, Magnetic signals of neurons are enriched with information about the movement of different part of the body such as wrist movement. In this paper, we use MEG (Magneto encephalography) signals of two subjects recorded during wrist movement task in four directions. Data were prepared for BCI competition 2008 for multiclass classification. Our approach for this classification problem consists of PCA as a noise reduction method, ULDA for feature reduction and various linear classifiers such as Bayesian, KNN and SVM. Final results (58%-62% for subject 1... 

    Development a planar neuro-musculoskeletal arm model in post-stroke patients

    , Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 236-241 ; 9781728156637 (ISBN) Nikzad Goltapeh, A ; Asghari, M ; Behzadipour, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Computational models of the central nervous system after a stroke helps to reveal the physiological mechanisms that may have strong impacts on the neuro-motor rehabilitation approaches. This paper studies the stroke subject's motor control mechanism in reaching movements by extending the previous study by incorporating the kinematics of motion as well as neural disconnection between the muscles and the CNS to further develop a planar patient specific neuro-musculoskeletal model of arm. The developed model was calibrated to eight post-stroke individuals by altering the Muscle Significance Factors (MFS) using numerical optimization to match the simulated motions with those measured... 

    Robust control of temperature during local hyperthermia of cancerous tumors

    , Article European Journal of Control ; Volume 52 , 2020 , Pages 67-77 Sayyaf, N ; Tavazoei, M. S ; Sharif University of Technology
    Elsevier Ltd  2020
    Local hyperthermia is one of the most common methods to treat cancerous tumors, near the skin surface or natural body orifices. In order to study the problem of temperature control during local hyperthermia, firstly the heat conduction process during this therapy is analytically modeled by a time-delayed fractional-order transfer function, parametrized with respect to the body temperature. Since the body temperature may vary under the influence of patient physiological reaction and heat source, a robustness criterion is proposed to achieve the phase margin invariance despite of the temperature variations. Afterwards, an analytical method is proposed to tune stabilizing FO-PI/PD controllers... 

    A novel approach to recognize hand movements via sEMG patterns

    , Article 29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07, Lyon, 23 August 2007 through 26 August 2007 ; 2007 , Pages 4907-4910 ; 05891019 (ISSN) ; 1424407885 (ISBN); 9781424407880 (ISBN) Khezri, M ; Jahed, M ; Sharif University of Technology
    Electromyogram signal (EMG) is an electrical manifestation of contractions of muscles. Surface EMG (sEMG) signal collected form surface of the skin has been used in diverse applications. One of its usages is exploiting it in a pattern recognition system which evaluates and synthesizes hand prosthesis movements. The ability of current prosthesis has been limited in simple opening and closing that decreases the efficacy of these devices in contrary to natural hand. In order to extend the ability and accuracy of prosthesis arm movements and performance, a novel approach for sEMG pattern recognizing system is proposed. In order to have a relevant comparison, present and recent research for... 

    Metabolic load comparison between the quarters of a game in elite male basketball players using sport metabolomics

    , Article European Journal of Sport Science ; Volume 21, Issue 7 , 2021 , Pages 1022-1034 ; 17461391 (ISSN) Khoramipour, K ; Gaeini, A. A ; Shirzad, E ; Gilany, K ; Chashniam, S ; Sandbakk, Ø ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Purpose: A basketball match is characterized by intermittent high-intensity activities, thereby relying extensively on both aerobic and anaerobic metabolic pathways. Here, we aimed to compare the metabolic fluctuations between the four 10-min quarters of high-level basketball games using metabolomics analyses. Methods: 70 male basketball players with at least 3 years of experience in the Iran national top-league participated. Before and after each quarter, saliva samples were taken for subsequent untargeted metabolomics analyses, where Principal component analysis (PCA) and Partial least squares-discriminant analysis (PLS-DA) were employed for statistical analysis. Results: Quarters 1 and 3... 

    The Investigation on Hydroxyapatite Coating on Magnesium Alloy and Its Properties

    , M.Sc. Thesis Sharif University of Technology Mazaheri Kalahrood, Amir (Author) ; Afshar, Abdollah (Supervisor)
    Magnesium and its alloys are biodegradable materials with mechanical properties similar to the bone tissue, therefore these materials are suitable for producing orthopedic implants. Unfortunately Magnesium and its alloys are corroded too fast in physiological environment which is the main obstacle for usage of these materials as orthopedic implants. Producing Hydroxyapatite(HA) coatings on surface of Magnesium and its alloys is one of the popular and useful methods for reducing the corrosion rate in physiological environment. HA is a biocompatible and bioactive coating with the ability to bond chemically with the bone tissue and therefore it is largely used as a bioactive coating on the... 

    Time-Frequency Representations in Biomedical Signal Processing

    , Article Time-Frequency Analysis: Concepts and Methods ; 2010 , Pages 353-382 ; 9781848210332 (ISBN) Senhadji, L ; Shamsollahi, M. B ; Sharif University of Technology
    Wiley-ISTE  2010
    Biomedical signals are acquired according to well-codified modalities. Space-time evolutions of their characteristics, correlated with clinical examination conditions, reveal the physiopathological state of the patient. These signals are non-stationary, and their non-stationary characteristics generally provide diagnostically useful information. Thus, the deployment of signal processing methodologies avoiding the assumption of stationarity is to be considered. During the last 20 years, time-frequency representations, particularly those belonging to Cohen's class, have been explored in various research fields within problems relevant to public health. Certain problems benefited from a new...