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Design and Assessment of Accuracy of a Patient-Specific Drill Guide Template for Thoracic Pedicle Screw Placement
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor)
Abstract
Fusion surgery or fixation of vertebrae in the spine is used to treat scoliosis, fractures, infections, tumors, spinal cord injuries, and disc herniation. In this type of surgery, two or more vertebrae are connected by special screws called pedicle screws to eliminate movement between the vertebrae. Given the serious risks of spinal fusion surgery, if the slightest mistake is made at the entry point or angle of the screw inside the vertebrae, the risk of spinal cord injury is very high, which is one of the complications of fusion surgery. Therefore, in order to increase the accuracy of screw placement, patient-specific template guides are used as drill guides in this operation. For this...
Effects of Spinal Fusion Surgery on the Kinetics of Adjacent Segments, Using Medical Imaging and Finite Element Modeling; Comparison with Musculoskeletal Model
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor)
Abstract
Passive finite element (FE) models of the spine are commonly used to simulate intact and various pre- and postoperative pathological conditions. Being devoid of muscles, these traditional passive FE models are driven by simplistic loading scenarios, e.g., a constant moment and compressive follower load (FL) that do not properly mimic the complex in vivo loading condition of the spine under muscle exertions. The present works therefore aims to develop novel passive FE models that are driven by more realistic yet simple loading scenarios, i.e., in vivo measured vertebral rotations and pathological-condition dependent FLs (estimated based on detailed musculoskeletal finite element (MS-FE) spine...
Improved artificial neural networks for 3D body posture and lumbosacral moment predictions during manual material handling activities
, Article Journal of Biomechanics ; Volume 131 , 2022 ; 00219290 (ISSN) ; Aghazadeh, F ; Arjmand, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Body posture measurement approaches, required in biomechanical models to assess risk of musculoskeletal injuries, are usually costly and/or impractical for use in real workplaces. Therefore, we recently developed three artificial neural networks (ANNs), based on measured posture data on several individuals, to predict whole body 3D posture (coordinates of 15 markers located on body's main joints), segmental orientations (Euler angles of 14 body segments), and lumbosacral (L5-S1) moments during static manual material handling (MMH) activities (ANNPosture, ANNAngle, and ANNMoment, respectively). These ANNs require worker's body height, body weight (only for ANNMoment), hand-load 3D position,...
The effects of intra-abdominal pressure on the stability and unloading of the spine
, Article Journal of Mechanics in Medicine and Biology ; Volume 12, Issue 1 , 2012 ; 02195194 (ISSN) ; Farahmand, F ; Shirazi Adl, A ; Arjmand, N ; Malekipour, F ; Parnianpour, M ; Sharif University of Technology
2012
Abstract
In spite of earlier experimental and modeling studies, the relative role of the intra-abdominal pressure (IAP) in spine mechanics has remained controversial. This study employs simple analytical and finite element (FE) models of the spine and its surrounding structures to investigate the contribution of IAP to spinal loading and stability. The analytical model includes the abdominal cavity surrounded by muscles, lumbar spine, rib cage and pelvic ring. The intra-abdominal cavity and its surrounding muscles are represented by a thin deformable cylindrical membrane. Muscle activation levels are simulated by changing the Young's modulus of the membrane in the direction of muscle fibers, yielding...
The validity and inter-rater reliability of a video-based posture-matching tool to estimate cumulative loads on the lower back
, Article Journal of Biomedical Physics and Engineering ; Volume 12, Issue 4 , 2022 , Pages 417-430 ; 22517200 (ISSN) ; Abdoli Eramaki, M ; Arjmand, N ; Abouhossein, A ; Zakerian, S. A ; Sharif University of Technology
Shriaz University of Medical Sciences
2022
Abstract
Background: Low back pain (LBP) is known as one of the most common workrelated musculoskeletal disorders. Spinal cumulative loads (CLs) during manual material handling (MMH) tasks are the main risk factors for LBP. However, there is no valid and reliable quantitative lifting analysis tool available for quantifying CLs among Iranian workers performing MMH tasks. Objective: This study aimed to investigate the validity and inter-rater reliability of a posture-matching load assessment tool (PLAT) for estimating the L5-S1 static cumulative compression (CC) and shear (CS) loads based on predictive regression equations. Material and Methods: This experimental study was conducted among six...
Mathematical and finite element modelling of spine to investigate the effects of intra-abdominal pressure and activation of muscles around abdomin on the spinal stability
, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Farahmand, F ; Parninapour, M ; Malekipour, F ; Shirazi Adl, A ; Arjmand, N ; Sharif University of Technology
2006
Abstract
In spite of the several experimental and modeling studies on the biomechanical characteristics of the human spine, the role and significance of the intra-abdominal pressure (IAP) in spine mechanics has remained controversial. This study represents a simple analytical and a 3-D finite element model of spine and its surrounding structures to investigate the contribution of IAP to spinal stability. The mathematical model included the lumbar spine column, the abdominal cavity and a muscular layer around it, the rib cage and the pelvic ring. The lumbar spine column was modeled as a beam and the rib cage and pelvis as rigid bodies. The intra-abdominal cavity and the surrounding muscular layer were...
Personalized disease-specific protein corona influences the therapeutic impact of graphene oxide
, Article Nanoscale ; Volume 7, Issue 19 , Apr , 2015 , Pages 8978-8994 ; 20403364 (ISSN) ; Raheb, J ; Akhavan, O ; Arjmand, S ; Mashinchian, O ; Rahman, M ; Abdolahad, M ; Serpooshan, V ; Laurent, S ; Mahmoudi, M ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred to as the 'personalized protein corona'). In this study, we demonstrate that graphene oxide (GO) sheets can trigger different...
The effect of parameters of equilibrium-based 3-D biomechanical models on extracted muscle synergies during isometric lumbar exertion
, Article Journal of Biomechanics ; Volume 49, Issue 6 , 2016 , Pages 967-973 ; 00219290 (ISSN) ; Sedaghat Nejad, E ; Rashedi, E ; Sedighi, A ; Arjmand, N ; Parnianpour, M ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
A hallmark of more advanced models is their higher details of trunk muscles represented by a larger number of muscles. The question is if in reality we control these muscles individually as independent agents or we control groups of them called "synergy". To address this, we employed a 3-D biomechanical model of the spine with 18 trunk muscles that satisfied equilibrium conditions at L4/5, with different cost functions. The solutions of several 2-D and 3-D tasks were arranged in a data matrix and the synergies were computed by using non-negative matrix factorization (NMF) algorithms. Variance accounted for (VAF) was used to evaluate the number of synergies that emerged by the analysis, which...
Synthesis of methyltriethoxysilane-modified calcium zinc phosphate nanopigments toward epoxy nanocomposite coatings: Exploring rheological, mechanical, and anti-corrosion properties
, Article Progress in Organic Coatings ; Volume 171 , 2022 ; 03009440 (ISSN) ; Alibakhshi, E ; Labani Motlagh, A ; Ramazani S. A., A ; Ghaderi, M ; Ramezanzadeh, B ; Mahdavian, M ; Arjmand, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this study, the effects of unmodified calcium zinc phosphate (UCZP) and modified calcium zinc phosphate (MCZP) nanopigments (NPs) on the rheological, mechanical, and corrosion protection performance (CPP) of the epoxy (EP) coatings were investigated. Transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to study morphology and overall chemical structure of synthesized calcium zinc phosphate (CZP) NPs, respectively. The grafting of methyltriethoxysilane (MTES) molecules on the surface of CZP was assessed using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and...
UiO-66 metal–organic frameworks in water treatment: A critical review
, Article Progress in Materials Science ; Volume 125 , 2022 ; 00796425 (ISSN) ; Molavi, H ; Rezakazemi, M ; Tajahmadi, S ; Bahi, A ; Ko, F ; Aminabhavi, T. M ; Li, J. R ; Arjmand, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Metal-organic frameworks (MOFs) have recently achieved much attention to eliminating toxic pollutants because of their attractive attributes, including large specific surface area, ultra-high porosity, abundant active adsorption sites, tunable surface chemistry, well-controlled pore size distribution, and strong host–guest interactions. Among the many developed MOFs, the Zr-based MOFs, particularly the UiO-66 family, are considered extremely attractive for wastewater treatment applications. The fascinating properties of UiO-66 such as high thermal stability, superior chemical resistance towards several solvents, including benzene, acetone, different alcohols, dimethylformamide, acidic and...
A rigid thorax assumption affects model loading predictions at the upper but not lower lumbar levels
, Article Journal of Biomechanics ; Volume 49, Issue 13 , 2016 , Pages 3074-3078 ; 00219290 (ISSN) ; Ferguson, S. J ; Arjmand, N ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
A number of musculoskeletal models of the human spine have been used for predictions of lumbar and muscle forces. However, the predictive power of these models might be limited by a commonly made assumption; thoracic region is represented as a single lumped rigid body. This study hence aims to investigate the impact of such assumption on the predictions of spinal and muscle forces. A validated thoracolumbar spine model was used with a flexible thorax (T1–T12), a completely rigid one or rigid with thoracic posture updated at each analysis step. The simulations of isometric forward flexion up to 80°, with and without a 20 kg hand load, were performed, based on the previously measured...
Effect of Obesity on Spinal Loads during Various Activities: A Combined in Vivo-Modeling Approach
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor)
Abstract
Obesity is a worldwide growing health challenge affecting ~30% of the world's population. Increased rate of disc degeneration and herniation, low back pain and surgery has been reported in obese individuals. Although obesity-related low back diseases have multifactorial etiology, presumably greater mechanical loads on the spine of heavier individuals during their daily activities may be considered as a risk factor. Likely larger trunk muscle sizes, disc sizes and thus passive stiffness in heavier individuals may however partly or fully offset the effect of their additional body weight on the spinal loads. In absence of in vivo approaches, the present study aims to construct subject-specific...
Prediction of the thorax/pelvis orientations and L5–S1 disc loads during various static activities using neuro-fuzzy
, Article Journal of Mechanical Science and Technology ; Volume 34, Issue 8 , 7 August , 2020 , Pages 3481-3485 ; ISSN: 1738494X ; Sayyaadi, H ; Arjmand, N ; Sharif University of Technology
Korean Society of Mechanical Engineers
2020
Abstract
Spinal posture including thorax/pelvis orientations as well as loads on the intervertebral discs are crucial parameters in biomechanical models and ergonomics to evaluate the risk of low back injury. In vivo measurement of spinal posture toward estimation of spine loads requires the common motion capture techniques and laboratory instruments that are costly and time-consuming. Hence, a closed loop algorithm including an artificial neural network (ANN) and fuzzy logic is proposed here to predict the L5–S1 segment loads and thorax/pelvis orientations in various 3D reaching activities. Two parts namely a fuzzy logic strategy and an ANN from this algorithm; the former, developed based on the...
Anomaly detection in the distribution grid: a nonparametric approach
, Article SEST 2020 - 3rd International Conference on Smart Energy Systems and Technologies, 7 September 2020 through 9 September 2020 ; 2020 ; Amiri, K ; Mohammadi Ivatloo, B ; Anvari Moghaddam, A ; Ebrahimnejad Shalmani, M ; Arjmand, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Owing to the development of smart grids technologies, including renewable energy resources and integrated demand response, the traditional distribution network undergoes systemic improvements and has become an active system. To meet such changes in technology, the smart distribution grid is highly dependent on communication infrastructures. Although this strong reliance can make the distribution network susceptible to cyber threats, there has been inadequate attention to the distribution network cyber-security. An intruder can disrupt communication and effectively target the distribution management system core functions, leaving the distribution grid susceptible to loss of stability...
A comprehensive evaluation of spine kinematics, kinetics, and trunk muscle activities during fatigue-induced repetitive lifting
, Article Human Factors ; 2021 ; 00187208 (ISSN) ; Mazloumi, A ; Arjmand, N ; Keihani, A ; Karimi, Z ; Ghasemi, M. S ; Kordi, R ; Sharif University of Technology
SAGE Publications Inc
2021
Abstract
Objective: Spine kinematics, kinetics, and trunk muscle activities were evaluated during different stages of a fatigue-induced symmetric lifting task over time. Background: Due to neuromuscular adaptations, postural behaviors of workers during lifting tasks are affected by fatigue. Comprehensive aspects of these adaptations remain to be investigated. Method: Eighteen volunteers repeatedly lifted a box until perceived exhaustion. Body center of mass (CoM), trunk and box kinematics, and feet center of pressure (CoP) were estimated by a motion capture system and force-plate. Electromyographic (EMG) signals of trunk/abdominal muscles were assessed using linear and nonlinear approaches. The L5-S1...
A comprehensive evaluation of spine kinematics, kinetics, and trunk muscle activities during fatigue-induced repetitive lifting
, Article Human Factors ; Volume 64, Issue 6 , 2022 , Pages 997-1012 ; 00187208 (ISSN) ; Mazloumi, A ; Arjmand, N ; Keihani, A ; Karimi, Z ; Ghasemi, M. S ; Kordi, R ; Sharif University of Technology
SAGE Publications Inc
2022
Abstract
Objective: Spine kinematics, kinetics, and trunk muscle activities were evaluated during different stages of a fatigue-induced symmetric lifting task over time. Background: Due to neuromuscular adaptations, postural behaviors of workers during lifting tasks are affected by fatigue. Comprehensive aspects of these adaptations remain to be investigated. Method: Eighteen volunteers repeatedly lifted a box until perceived exhaustion. Body center of mass (CoM), trunk and box kinematics, and feet center of pressure (CoP) were estimated by a motion capture system and force-plate. Electromyographic (EMG) signals of trunk/abdominal muscles were assessed using linear and nonlinear approaches. The L5-S1...
Fractional Brownian Motion and Stochastic Differential Equations Driven by Fractional Noise
, Ph.D. Dissertation Sharif University of Technology ; Zohori Zangeneh, Bijan (Supervisor)
Abstract
This thesis has been prepared in six chapters. In the first chapter, the necessary analytical preliminaries are revised. The second chapter is specified on the introducing of the fractional Brownian motion and the description of some of its properties. The subject of the third chapter is simulation. The practical utilization of stochastic models usually needs simulation; therefore the fractional Brownian motion and the processes derived from it are not exempted either. The fifth chapter is consisted of two major parts; the first part is the simulation of fractional Brownian motion, in which no new work has been done, and only one of the available methods has been explained. The second part...
A QoS-Aware Routing Algorithm in Wireless Multimedia Sensor Network Using Cross-Layer Information
, M.Sc. Thesis Sharif University of Technology ; Khansari, Mohammad (Supervisor)
Abstract
In this thesis, we propose a QoS-aware routing algorithm for multimedia streaming that uses cross-layer information (application layer and physical layer) in Wireless Multimedia Sensor Networks (WMSN). Our goal is to use cross-layer information to route video packets efficiently and deliver a higher quality video in streaming applications. Our QoS-Aware Multi-Path Selection (QAMPS) method is based on multi-path multi-priority selection algorithm that uses Two-Phase geographic Greedy Forwarding (TPGF) as a routing algorithm. The proposed method guarantees QoS by splitting video streams into I-frames, P-frames and B-frames in the application layer and passes them to the network layer for...
Effect of considering stability requirements on antagonistic muscle activities using a musculoskeletal model of the human lumbar spine
, Article 2013 20th Iranian Conference on Biomedical Engineering, ICBME 2013 ; 2013 , Pages 260-264 ; Nickpour, H ; Arjmand, N ; Farahmand, F ; Sharif University of Technology
2013
Abstract
The recruitment pattern of trunk muscles is determined using a three-dimensional model of the spine with two joints and six symmetric pairs of muscles in which both equilibrium and stability requirements are satisfied. Model predictions are verified using Anybody Modeling System (AMS) and Abaqus. The model is used to test the hypothesis that antagonistic muscle activities are necessary for the spinal stability. The model with stability constraints predicts muscle activities greater than those predicted without stability consideration. In agreement with experimental data, the stability-based model predicts antagonistic muscle activities. It is shown that spinal stability increases with trunk...
Effect of Obesity on Spinal Loads during Various Activities: A Combined in Vivo-Modeling Approach
, M.Sc. Thesis Sharif University of Technology ; Arjmand, Navid (Supervisor) ; Parnianpour, Mohammad (Supervisor)
Abstract
Obesity is a worldwide growing health challenge affecting ~30% of the world's population. Increased rate of disc degeneration and herniation, low back pain and surgery has been reported in obese individuals. Although obesity-related low back diseases have multifactorial etiology, presumably greater mechanical loads on the spine of heavier individuals during their daily activities may be considered as a risk factor. Likely larger trunk muscle sizes, disc sizes and thus passive stiffness in heavier individuals may however partly or fully offset the effect of their additional body weight on the spinal loads. In absence of in vivo approaches, the present study aims to construct subject-specific...