Search for: physiological-models
Total 35 records
Sex-Dependent estimation of spinal loads during static manual material handling activities—combined in vivo and in silico analyses, Article Frontiers in Bioengineering and Biotechnology ; Volume 9 , 2021 ; 22964185 (ISSN) ; Arjmand, N ; Pan, F ; Zander, T ; Schmidt, H ; Sharif University of Technology
Frontiers Media S.A 2021
Manual material handling (MMH) is considered as one of the main contributors to low back pain. While males traditionally perform MMH tasks, recently the number of females who undertake these physically-demanding activities is also increasing. To evaluate the risk of mechanical injuries, the majority of previous studies have estimated spinal forces using different modeling approaches that mostly focus on male individuals. Notable sex-dependent differences have, however, been reported in torso muscle strength and anatomy, segmental mass distribution, as well as lifting strategy during MMH. Therefore, this study aimed to use sex-specific models to estimate lumbar spinal and muscle forces during...
Probe into the molecular mechanism of ibuprofen interaction with warfarin bound to human serum albumin in comparison to ascorbic and salicylic acids: Allosteric inhibition of anticoagulant release, Article Journal of Chemical Information and Modeling ; Volume 61, Issue 8 , 2021 , Pages 4045-4057 ; 15499596 (ISSN) ; Taghikhani, E ; Sharif University of Technology
American Chemical Society 2021
The release of anticoagulant drugs such as warfarin from human serum albumin (HSA) has been important not only mechanistically but also clinically for patients who take multiple drugs simultaneously. In this study, the role of some commonly used drugs, including s-ibuprofen, ascorbic acid, and salicylic acid, was investigated in the release of warfarin bound to HSA in silico. The effects of the aforementioned drugs on the HSA-warfarin complex were investigated with molecular dynamics (MD) simulations using two approaches; in the first perspective, molecular docking was used to model the interaction of each drug with the HSA-warfarin complex, and in the second approach, drugs were positioned...
Gut-on-a-chip: Current progress and future opportunities, Article Biomaterials ; Volume 255 , 2020 ; Nasiri, R ; Barros, N. R. D ; Tebon, P ; Thakor, J ; Goudie, M ; Shamloo, A ; Martin, M. G ; Khademhosseni, A ; Sharif University of Technology
Elsevier Ltd 2020
Organ-on-a-chip technology tries to mimic the complexity of native tissues in vitro. Important progress has recently been made in using this technology to study the gut with and without microbiota. These in vitro models can serve as an alternative to animal models for studying physiology, pathology, and pharmacology. While these models have greater physiological relevance than two-dimensional (2D) cell systems in vitro, endocrine and immunological functions in gut-on-a-chip models are still poorly represented. Furthermore, the construction of complex models, in which different cell types and structures interact, remains a challenge. Generally, gut-on-a-chip models have the potential to...
Effects of human stature and muscle strength on the standing strategies: A computational biomechanical study, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 234, Issue 7 , 2020 , Pages 674-685 ; Azghani, M. R ; Parnianpour, M ; Khalaf, K ; Sharif University of Technology
SAGE Publications Ltd 2020
It has been hypothesized that the muscular efforts exerted during standing may be altered by changes in personal factors, such as the body stature and muscular strength. The goal of this work was to assess the contribution of leg muscles using a biomechanical model in different physical conditions and various initial postures. An optimized inverse dynamics model was employed to find the maximum muscular effort in 23,040 postures. The simulation results showed that mid-range knee flexion could help the healthy and strong individuals maintain balance, but those with weaker muscle strength required more knee flexion. Individuals of weak muscular constitution as well as those with tall stature...
Evaluation of endothelial response to reactive hyperaemia in peripheral arteries using a physiological model, Article International Journal of Biomedical Engineering and Technology ; Volume 33, Issue 4 , 2020 , Pages 305-324 ; Zahedi, E ; Vahdat, B. V ; Sharif University of Technology
Inderscience Publishers 2020
Non-invasive measurement of flow-mediated dilation (FMD) in the brachial artery for assessing endothelial function is costly and operator-dependent, limiting its application to research cases. In this paper, an approach based on a physiological model between normalized central blood pressure and finger photoplethysmogram is presented. Baseline model parameters are estimated using a genetic algorithm in 30 subjects consisting of ten normal blood pressure (BP), ten high-BP and ten elderly volunteers. Beat-to-beat fitness values after reactive hyperaemia are calculated using baseline (before cuff occlusion) data. Results show that stimulus-induced changes are fairly described with a first order...
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) ; 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...
Effects of different corneal ring segments with identical total arc length on keratoconic eyes: a finite element study, Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 1-3 ; 9781728156637 (ISBN) ; Sajadi, S. B ; Khanlari, M ; Gholami, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
Keratoconus (KC) is a progressive corneal disease. It is mostly characterized by corneal thinning and irregular steepening as well as formation of cone-shaped regions on the cornea. Amongst treatment modalities, implantation of Intrastromal Corneal Ring Segments (ICRSs) could decrease corneal surface irregularities. However, controversy exists over the selection of proper ICRSs. Here, the aim was to compare the effects of two sets of ICRSs. The ICRSs were identical both in cross-section and total arc length. The results showed that under normal physiological range of intraocular pressures (IOPs), the two selected ICRSs caused slightly different deformations in the same in-silico keratoconic...
A novel integrated framework to evaluate greenhouse energy demand and crop yield production, Article Renewable and Sustainable Energy Reviews ; Volume 96 , 2018 , Pages 487-501 ; 13640321 (ISSN) ; Heeren, N ; Hellweg, S ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd 2018
Greenhouses are complex systems that require considerable amounts of energy. In order to optimize their performance, it is necessary to reduce the amount of energy per unit of crop produced. This requires a combined assessment of greenhouse energy balance and crop growth, as well as their interaction. In this work, more than 30 existing greenhouse models are reviewed and different algorithms are combined to propose an integrated energy-yield model. The physical model of greenhouse energy demand is based on the dynamic energy and mass balance while yield production is based on a physiological crop model. The integrated model is validated with observed energy demand and crop yield datasets...
Cuffless blood pressure estimation algorithms for continuous health-care monitoring, Article IEEE Transactions on Biomedical Engineering ; Volume 64, Issue 4 , 2017 , Pages 859-869 ; 00189294 (ISSN) ; Kiani, M. M ; Mohammadzade, H ; Shabany, M ; Sharif University of Technology
IEEE Computer Society 2017
Goal: Continuous blood pressure (BP) monitoring can provide invaluable information about individuals' health conditions. However, BP is conventionally measured using inconvenient cuff-based instruments, which prevents continuous BP monitoring. This paper presents an efficient algorithm, based on the pulse arrival time (PAT), for the continuous and cuffless estimation of the systolic BP, diastolic blood pressure (DBP), and mean arterial pressure (MAP) values. Methods: The proposed framework estimates the BP values through processing vital signals and extracting two types of features, which are based on either physiological parameters or whole-based representation of vital signals. Finally,...
Design and analysis of a novel parallel mechanism for prosthetic knee wear test simulators, Article Journal of Mechanical Science and Technology ; Volume 31, Issue 2 , 2017 , Pages 885-892 ; 1738494X (ISSN) ; Farahmand, F ; Durali, M ; Abedinnasab, M. H ; Sharif University of Technology
Korean Society of Mechanical Engineers 2017
Using a parallel mechanism in the wear test simulators of prosthetic knees provides an easy access to the femoral and tibial components during tests. Moreover, because of its higher accuracy and load capacity, in comparison with serial mechanisms, it allows simulation of heavier tasks, such as climbing stairs, to be performed. This paper describes a new 3 Degree of freedom (DoF) spatial 2T1R (T: Translational DoF; R: Rotational DoF) parallel mechanism, for reproducing the force and motion of the tibial component of the knee prostheses in a wear test simulator. Kinematics and dynamics analysis of the mechanism indicated that it can satisfy the required DoFs, workspace and load capacity...
Robust control of LVAD based on the sub-regional modeling of the heart, Article Scientia Iranica ; Volume 23, Issue 6 , 2016 , Pages 2934-2943 ; 10263098 (ISSN) ; Jahed, M ; Sharif University of Technology
Sharif University of Technology 2016
Left Ventricular Assist Devices (LVAD) have received renewed interest as a bridge-to-transplantation as well as a bridge-to-recovery device. Ironically, reports of malfunction and complications have hindered the growth of this device. In particular, the main concern is LVAD's susceptibility to excessive backlash and suction as a result of ows that are either too low or high, respectively. This study utilizes a well-established physiological model of the cardiovascular system as a reliable platform to study a proposed adaptive robust controller for a rotary motor based LVAD which overcomes such shortcomings. Proposed controller performance is evaluated by comparing simulated natural heart...
Prosthetic knee using of hybrid concept of magnetorheological brake with a T-shaped drum, Article 2015 IEEE International Conference on Mechatronics and Automation, ICMA 2015, 2 August 2015 through 5 August 2015 ; Aug , 2015 , Pages 721-726 ; 9781479970964 (ISBN) ; Zareh, S. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2015
This paper focuses on developing a new configuration on magnetorheological (MR) brake damper as prosthetic knee. Knee uses magnetic fields to vary the viscosity of the MR fluid, and thereby its flexion resistance. Exerted transmissibility torque of the knee greatly depends on the magnetic field intensity in the MR fluid. In this study a rotary damper using MR fluid is addressed in which a single rotary disc will act as a brake while MR fluid is activated by magnetic field in different walking gait. The main objective of this study is to investigate a prosthetic knee with one activating rotary disc to accomplish necessary braking torque in walking gait via implementing of Newton's equation of...
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) ; 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...
Effect of body weight on spinal loads in various activities: A personalized biomechanical modeling approach, Article Journal of Biomechanics ; Volume 48, Issue 2 , 2015 , Pages 276-282 ; 00219290 (ISSN) ; Arjmand, N ; Shirazi Adl, A ; Sharif University of Technology
Elsevier Ltd 2015
Epidemiological studies are divided over the causative role of body weight (BW) in low back pain. Biomechanical modeling is a valuable approach to examine the effect of changes in BW on spinal loads and risk of back pain. Changes in BW have not been properly simulated by previous models as associated alterations in model inputs on the musculature and moment arm of gravity loads have been neglected. A detailed, multi-joint, scalable model of the thoracolumbar spine is used to study the effect of BW (varying at five levels, i.e., 51, 68, 85, 102, and 119kg) on the L5-S1 spinal loads during various static symmetric activities while scaling moment arms and physiological cross-sectional areas of...
Effect of stimuli-responsive nano haydrogel finishing on cotton fabric properties, Article Indian Journal of Fibre and Textile Research ; Volume 40, Issue 4 , 2015 , Pages 431-436 ; 09710426 (ISSN) ; Hemmati Nejad, N ; Pourjavadi, A ; Sharif University of Technology
National Institute of Science Communication and Information Resources (NISCAIR) 2015
Cotton fabrics have been prepared with smart properties by functional finishing with stimuli-responsive nano gel. A biopolymer (chitosan) and a synthetic polymer (poly-NiPAAm) have been used for the synthesis of nano gel through semi-batch surfactant-free dispersion polymerization (SB-SFDP) method. The incorporation of nano gel to textile fabrics is achieved by pad-dry-cure procedure, using an aqueous nano gel dispersion and 1,2,3,4-butantetracarboxylic acid as a crosslinking agent. With this cross linking method, it is possible to integrate the nano gel into the cotton fabric’s structure with good resistance to washing. The changes in physiological comfort parameters of cotton fabric such...
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) ; 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 robotic model of transfemoral amputee locomotion for design optimization of knee controllers, Article International Journal of Advanced Robotic Systems ; Volume 10 , 2013 ; 17298806 (ISSN) ; Farahmand, F ; Osman, N. A. A ; Zohoor, H ; Sharif University of Technology
A two-dimensional, seven link, nine degrees of freedom biped model was developed to investigate the dynamic characteristics of normal and transfemoral amputee locomotion during the entire gait cycle. The equations of motion were derived using the Lagrange method and the stance foot-ground contact was simulated using a five-point penetration model. The joint driving torques were obtained using forward dynamic optimization of the normal human gait and applied to the intact joints of the amputee. Three types of motion controllers; frictional, elastic and hydraulic were considered for the prosthetic joints of the amputee and their design parameters were optimized to achieve the closest...
A novel distributed model of the heart under normal and congestive heart failure conditions, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 227, Issue 4 , 2013 , Pages 362-372 ; 09544119 (ISSN) ; Jahed, M ; Sharif University of Technology
Conventional models of cardiovascular system frequently lack required detail and focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the cardiovascular system. It utilizes noninvasive blood flow and pressure seed data and temporal cardiac muscle regional activity to predict the operation of the heart under normal and congestive heart failure conditions. The analysis considers specific regions of the heart, namely, base, mid and apex of left ventricle. The proposed method of parameter estimation for hydraulic electric analogy model is recursive least squares algorithm. Based on simulation results and comparison...
Introducing a distributed model of the heart, Article Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics, 24 June 2012 through 27 June 2012 ; June , 2012 , Pages 419-424 ; 21551774 (ISSN) ; 9781457711992 (ISBN) ; Jahed, M ; Sharif University of Technology
Conventional models of cardiovascular system (CV) frequently lack required detail. Once utilized to study the heart function, these models focus primarily on the overall relationship between pressure, flow and volume. This study proposes a localized and regional model of the CV system. It utilizes non-invasive blood flow and pressure seed data and temporal cardiac muscle regional activation to predict the operation of the heart. Proposed localized analysis considers specific regions of the heart, namely base, mid and apex sections of the left ventricle. This modular system is based on a hydraulic electric analogy model, estimating desired parameters, namely resistance (R), compliance (C),...
Efficient biodegradation of naphthalene by a newly characterized indigenous achromobacter sp. FBHYA2 isolated from Tehran oil refinery complex, Article Water Science and Technology ; Volume 66, Issue 3 , March , 2012 , Pages 594-602 ; 02731223 (ISSN) ; Borghei, S. M ; Hassani, A. H ; Yakhchali, B ; Ardjmand, M ; Zeinali, M ; Sharif University of Technology
IWA Pub 2012
A bacterial strain, FBHYA2, capable of degrading naphthalene, was isolated from the American Petroleum Institute (API) separator of the Tehran Oil Refinery Complex (TORC). Strain FBHYA2 was identified as Achromobacter sp. based on physiological and biochemical characteristics and also phylogenetic similarity of 16S rRNA gene sequence. The optimal growth conditions for strain FBHYA2 were pH 6.0, 30°C and 1.0% NaCl. Strain FBHYA2 can utilize naphthalene as the sole source of carbon and energy and was able to degrade naphthalene aerobically very fast, 48 h for 96% removal at 500 mg/L concentration. The physiological response of Achromobacter sp., FBHYA2 to several hydrophobic chemicals...