Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Mohsen Naji; Seyed Mohammad Firouzabadi; Sedighe Kahrizi
Volume 7, Issue 1 , June 2013, , Pages 13-20
Abstract
The collected electromyogram (EMG) signals from trunk musculature (e.g., rectus abdominis and external oblique muscle) are often contaminated with the heart muscle electrical activity (ECG). This paper introduces a novel method, the Empirical Mode Decomposition, for elimination of ECG contamination from ...
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The collected electromyogram (EMG) signals from trunk musculature (e.g., rectus abdominis and external oblique muscle) are often contaminated with the heart muscle electrical activity (ECG). This paper introduces a novel method, the Empirical Mode Decomposition, for elimination of ECG contamination from EMG signals. The method is compared to a Butterworth high pass filtering. Results obtained from the analysis of generated and experimental EMG signals show that our method outperforms the high pass filtering for elimination of ECG contamination from trunk EMG signals.
Biomechanics of Bone / Bone Biomechanics
Mohammad Mehdi Khani; Mohammad Tafazzoli Shadpour; Farzane Aghajani; Peyman Naderi
Volume 5, Issue 1 , June 2011, , Pages 13-20
Abstract
Stress analysis is a proper tool in evaluation of vulnerable regions of dental tissues exposed to cyclic loading due to mastication and other physiological functions. In this study, effects of visco-elastic property of dental components on the distribution of stress are investigated in finite element ...
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Stress analysis is a proper tool in evaluation of vulnerable regions of dental tissues exposed to cyclic loading due to mastication and other physiological functions. In this study, effects of visco-elastic property of dental components on the distribution of stress are investigated in finite element models of upper central tooth prone to dynamic loading. Sensitivity of stress pulse to the visco-elastic property is studied. Results indicate reduction of stress pulse amplitude by elevation of visco-elastic parameter with highest effect in enamel-cementum junction and then in enamel-dentin junction. The visco-elastic property causes smoothening of the stress distribution in dental tissues. Such effect is due to reduction of stress wave amplitude and elevation of the ratio of minimum to maximum stress values. Increased visco-elasticity of components results in elevated phase shift between load and stress waves and higher attenuation of stress wave. This causes slow propagation of attenuated wave leading to lower maximum stress after reflection of stress wave in boundaries and junctions.
Bioheat Transfer
Seyed Alireza Zolfaghari; Mehdi Maerefat; Amir Omidvar
Volume 4, Issue 1 , June 2010, , Pages 13-21
Abstract
Generally, most of the human thermal response models are dependent upon a narrow range of personal/environmental parameters. In other words, the effects of other parameters such as eating foods are not considered in these models. On the other hand, previous studies have indicated that the overall thermal ...
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Generally, most of the human thermal response models are dependent upon a narrow range of personal/environmental parameters. In other words, the effects of other parameters such as eating foods are not considered in these models. On the other hand, previous studies have indicated that the overall thermal condition of the body can be significantly affected by eating cold or hot foods. In the present study, the time-dependent thermal response of the human body is simulated with considering the effect of eating hot/cold food. This simulation is performed by adding an extra term to Gagge’s transient model. In this study, three thermal conditions of the human body (hot, neutral and cold) are considered and the effects of eating hot/cold food are investigated under the mentioned conditions. Results indicate that the effects of eating hot or cold food are not negligible during the eating time and also in a period of time after that. At the neutral condition, the human thermal sensation is more sensitive to hot food than to cold ones. Eating hot food changes the body thermal sensation from neutral to hot. But, eating cold food would not make significant changes in the thermal sensation of the body. Results also show that cold food changes the body core temperature more than hot food. While hot food influences the skin temperature significantly.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Farzaneh Dasar; Majid Ghoshuni; Ghasem Sadeghi Bajestani
Volume 14, Issue 1 , May 2020, , Pages 13-22
Abstract
Autism spectrum disorder is a developmental disorder that involves disorders in social interaction and communication and repetitive or stereotypical behavior. In some children with autism, the sensitivity to acoustic stimuli is much higher than normal (hypersensitive) versus in some other children, this ...
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Autism spectrum disorder is a developmental disorder that involves disorders in social interaction and communication and repetitive or stereotypical behavior. In some children with autism, the sensitivity to acoustic stimuli is much higher than normal (hypersensitive) versus in some other children, this sensitivity is less than normal (hyposensitive). In this study a method for evaluation of auditory system of hypersensitive and hyposensitive autism children using event related potentials (ERPs) was presented. The EEG signal was recorded from 10 autism children (2 girls) with average age of 7.7±2.31 years. In order to record ERPs, 2000 audio stimulation based on the MissMatch Negetivity (MMN) Pattern was presented to participants. These stimulus include 1600 standard sounds with a frequency of 1000 Hz, deviant at 1300 Hz, and noise at frequencies of 1500-1000, 500 and 2000 Hz. In order to analyze ERP data, 18 time domain features have been extracted from the ERP components in all three types of stimulation (standard, deviation, noise). Based on the results, in the deviant stimuli, total positive area of the Pz channel in the hypersensitive group was significantly increased (p=0.028) compared to the hyposensetive group. Also, in the noise stimuli, total positive area in C4 and Pz channels has significantly increased (p=0.028, p=0.009) in the hyposensitive group compared to hypersensetive group. In conclusion, when hypersensitive children were exposed to deviant stimulue, neural activity was increased in parietal lobe, wheras in hyposensitive children neural activity increased in central and parietal lobe during noise stimulue. Therefore, this method can be useful in assessing children's autism spectrum in terms of hearing loss sensitivity.
Biomechanical Devices
Mohammad Khavary; Mahdi Bamdad
Volume 15, Issue 1 , May 2021, , Pages 13-27
Abstract
Nowadays, one of the most effective tools for restoring patients' mobility and muscles strength is the use of stationary cycling exercises and pedaling. In this study, two methods for the treatment of lower limbs are made possible by the design, control implementation, and construction of an intelligent ...
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Nowadays, one of the most effective tools for restoring patients' mobility and muscles strength is the use of stationary cycling exercises and pedaling. In this study, two methods for the treatment of lower limbs are made possible by the design, control implementation, and construction of an intelligent exercise bike. According to the damage level, the patient will fall into the active-assisted training or passive training group. In a passive training program, patients do not have enough ability to pedal on the bike, so the motor will provide the power to reach a predefined pedaling speed. In this program, feet of patients will pedal at a constant speed above the speed patient is able to achieve compulsorily. In an active-assisted training program, the patient is already improved enough to have a higher ability to pedal at the same constant speed and the motor will provide less power according to the pedaling power of the patient. Hence, the provided power by the motor is set based on the provided force by the patient. In this study, it is aimed to design the control theory for these two treatment methods and this bike. Furthermore, speed control was done by force and speed feedback. Experimental and theoretical results showed that the implementation and equipping of stationary bike with the mentioned method has led the research to the goals of speed control for rehabilitation use. Eventually, the experimental results show an average accuracy of 98.71% for the passive method in the test sample reported in this study and 98.24% for the six tests after reaching a steady state speed. Also, these results are 96.33% for the active-assisted mode and for the test reported in this study; and 95.59% for four tests to reach the desired pedaling speed.
Biomedical Image Processing / Medical Image Processing
Mohammad Hosein Miranbeigi; Leila Mohammadi; Sahar Moghimi; Giti Torkaman
Volume 3, Issue 1 , June 2009, , Pages 15-24
Abstract
Collagen content and its configuration are considered to be among important criteria of healing in tissues. Therefore, developing a method to estimate these factors can benefit physicians in terms of valuable information. In this paper, we examine variation of collagens in tissue mimicking phantoms as ...
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Collagen content and its configuration are considered to be among important criteria of healing in tissues. Therefore, developing a method to estimate these factors can benefit physicians in terms of valuable information. In this paper, we examine variation of collagens in tissue mimicking phantoms as well as in vivo tissue taking advantage of applying image processing techniques on ultrasound images of samples. In phantoms, as the base tissue we have used agar-water matrix material and graphite to simulate collagen, respectively. We also have used different concentrations of graphite to simulate different contents of collagen according to attenuation coefficient of ultrasound waves in soft tissue and its correlation with weight ratio of graphite. Experimental and simulation results show that increase in concentration of graphite in phantoms results in higher energy and more contrast level in B-Mode images (r=0.99, p
Neuro-Muscular Engineering
Ali Esteki
Volume -1, Issue 1 , June 2004, , Pages 15-23
Abstract
Computer simulation of a three dimensional model of the thumb and index finger was used to perform a sensitivity analysis of each joint position to individual muscle activation level. The results were used to study the effect of each muscle on hand posture and select specific muscles to get a desired ...
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Computer simulation of a three dimensional model of the thumb and index finger was used to perform a sensitivity analysis of each joint position to individual muscle activation level. The results were used to study the effect of each muscle on hand posture and select specific muscles to get a desired posture of the hand to assist the implementation of FNS systems. The hand was treated as a multi-body system including rigid segments connected by joints. Each joint was subjected to a total moment including muscle active and joint passive components. The forward approach, in which the equilibrium equations are solved for joint positions as a function of muscle moments, was used. The results showed that at the base joint of the index finger, flexion effect of the extrinsic flexor muscles was about two times of that of the intrinsic muscles. It was also shown that each muscle of the extensor system is individually more effective than the extrinsic flexor muscles. At the more distal joints, intrinsic muscles acted as feeble extensors. At the base joint of the thumb, extensor muscles were much more powerful than the flexor and flexor effect of adductor muscles. Also, abductor muscles were much more effective than the adductors. It was revealed that flexor muscles of the more distal joints are as strong as the extensor muscles. The conclusions are that: the minimum required muscles for appropriate positioning of the hand and for grasp and applying force to objects are limited.
Gait Analysis
Maryam Hajizade; Alireza Hashemi Oskouei; Farzan Ghalichi; Farhad Tabatabai Ghomshe; Mohammad Razi; Gisela Solo
Volume 9, Issue 1 , April 2015, , Pages 17-31
Abstract
Patients with ACL deficiency (ACLD) have to use different compensatory mechanisms to maintain their stability during daily activities. The aim of this study is to determine the differences in 3D kinematics and peak ground reaction forces (GRF) between ACL deficient legs and healthy contralateral legs ...
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Patients with ACL deficiency (ACLD) have to use different compensatory mechanisms to maintain their stability during daily activities. The aim of this study is to determine the differences in 3D kinematics and peak ground reaction forces (GRF) between ACL deficient legs and healthy contralateral legs during stair ascent. Eight subjects with unilateral ACL deficiency participated in this study. Healthy contralateral legs were considered as control group for further comparisons to ACL deficient legs. A six camera VICON motion analysis system and 2 portable force plates were used to record the locomotion while walking up custom-made stairs with two different step heights. Advanced OSSCA technique was used to assess tibiofemoral knee kinematics, a combination of symmetrical axis of rotation (SARA), symmetrical center of rotation estimation (SCoRE) and optimal common shape technique (OCST). The results of this study show that participants with ACLD experienced different kinematics and peak GRFs in different step heights (p<0.05). During ascending stairs with 17cm height, legs with ACLD exhibited less varus, more external rotation and less impact peak in pre-swing stance and early swing phase compared to contralateral healthy leg (p<0.05). The other stair height, 20 cm, resulted in more extension, more valgus and more external tibia rotation in injured leg compared to contralateral leg during terminal extension of stance phase (p<0.05). In both step heights, injured leg reached it maximum extension peak at an earlier time. The results of this study imply that participants with ACLD make use of different 3D rotational tiobiofemoral kinematics and different GRF compared to healthy contralateral leg. These compensatory mechanisms would finally bring about different knee joint loading, which provides the potential of cartilage degeneration and early osteoarthritis.
Biomedical Image Processing / Medical Image Processing
Saeid Shakeri; Farnaz Ghassemi; Farshad Almasganj
Volume 13, Issue 1 , April 2019, , Pages 17-30
Abstract
Noise removal is one of the most important steps in digital image processing. Cone beam computed tomography (CBCT) is increasingly utilized in maxillofacial and dental imaging. Compared to conventional CT, CBCT images have diffrent noise and artifacts due to much less applied dose and their reconstruction ...
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Noise removal is one of the most important steps in digital image processing. Cone beam computed tomography (CBCT) is increasingly utilized in maxillofacial and dental imaging. Compared to conventional CT, CBCT images have diffrent noise and artifacts due to much less applied dose and their reconstruction algorithm. Therefore, the use of noise reduction techniques in these images is necessary to increase the signal-to-noise ratio. In this paper, the independent component analysis (ICA) method has been used to seperate noise from CBCT images and three different ICA algorithms, NG-FICA, ERICA and FastICA were investigated. In addition, two powerful noise reduction method, 2D discrete wavelet thresholding and optimized anisotropic diffusion filter is used to evaluate the results. Our proposed method has been validated on 12 different images in the presence of Gaussian and Spectral noise and the results are evaluated using processing time criteria, PSNR, MSE and SSIM. The results show that the ICA methods have advantage in noise reduction from CBCT images compared to the other noise reduction methods and among the three studied ICA algorithms, the NG-FICA algorithm has better performance in terms of processing time, preserving image quality and noise reduction.
Neuro-Muscular Engineering
Reza Hajian; Farzad Towhidkhah
Volume 8, Issue 1 , March 2014, , Pages 19-29
Abstract
Tremor is one of the most frequent movement disorders which is involuntary and approximately sinusoidal. It affects various body joints such as elbow. Tremor on an elbow is considered as extension, flection, and rotation of the forearm. There are miscellaneous types of treatments for tremor one of which ...
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Tremor is one of the most frequent movement disorders which is involuntary and approximately sinusoidal. It affects various body joints such as elbow. Tremor on an elbow is considered as extension, flection, and rotation of the forearm. There are miscellaneous types of treatments for tremor one of which is electrical stimulation. In this research, we study existing stimulation methods in order to reduce tremor and control stimulation pulses. It should be notified that studying these methods requires 1- an electrical stimulator so that one can run natural experiments and estimate the validity of the model, 2- a skeletal- neuromuscular model in order to study the tremor dynamics and the system simulation, and 3- determining an appropriate stimulation scheme and control method in order that one can control the stimulation parameters to reduce tremor. The antagonist muscle stimulation technique for reducing tremor is in the form of either muscle co-contraction or anti-phase stimulation. In the former method, considering the fact that the time-dependent system has time-delay, disturbance, and non-linearities, a robust controller is needed. Hence, in this study, we take advantage of MPC controller because of its features. The results show that MPC controller is more satisfactory than the PID and fuzzy ones used in previous works and also demonstrate that one can theoretically reduce tremor by applying appropriate electrical stimulation.
Musculoskeletal Systems Modeling
Elham Hazrati; Mahmoud Reza Azghani
Volume 11, Issue 1 , May 2017, , Pages 19-28
Abstract
Pedaling is one of the common physical activities for muscles strengthening. Pedaling performance is affected by various factors. The purpose of this study is investigating the effect of pedaling rate and resistance moment against pedaling in the feasible pedaling places (kinematics view) on the muscles ...
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Pedaling is one of the common physical activities for muscles strengthening. Pedaling performance is affected by various factors. The purpose of this study is investigating the effect of pedaling rate and resistance moment against pedaling in the feasible pedaling places (kinematics view) on the muscles activity and ankle, knee and hip joints forces. For this purpose, the biomechanical model of human movement system presented in AnyBody software, is used. The mechanical power of pedaling is deemed to constant (200 w). The Pedaling rate of 40, 60, 80, 100 and 120 rpm and the resistance moment of 0, 5, 10, 15 and 20 Nm, are considered in the pedaling feasible places. Results indicate that although the range of pedaling feasible places is proper by the kinematics view, however changing the pedaling rate and the applied resistance moment, all of the pedaling places from this range cannot be proper due to the excessive muscles activity (more than 0.95). In the pedaling rate of 80, 100 and 120 rpm by applying the resistance moment of 0 and 5 Nm, approximately all of the feasible places are suitable (muscles activity are less than 0.95). By increasing the pedaling rate in a constant resistance moment, the large part and reversely, by increasing the resistance moment in a constant pedaling rate, the small part of feasible range are appropriate. Joints forces increase with decreasing the pedaling rate and increasing the applied resistance moment.
Biofluid Mechanics / Biofluids
Pooya Abdi; Bahman Vahidi
Volume 17, Issue 1 , May 2023, , Pages 41-50
Abstract
Topography of extracellular matrix plays a major role in many biological events including tissue healing, morphogenesis and growth. It is known that matrix constitution and mechanical properties are deciding factors in governing the fate of its inhabitant cells. Besides the direct mechanical cues, matrices ...
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Topography of extracellular matrix plays a major role in many biological events including tissue healing, morphogenesis and growth. It is known that matrix constitution and mechanical properties are deciding factors in governing the fate of its inhabitant cells. Besides the direct mechanical cues, matrices also facilitate the release and uptake of certain chemicals and participate in cell-cell and cell-ECM crosstalk. Mechanical strains in the matrix are proved to direct endothelial cell migration and elongation leading to angiogenesis, and there is a consensus that matrix stiffness, fiber density and fiber orientation can enhance angiogenesis in the preferred direction of stiffness gradient. In this study, we specifically investigated the role of topography in guidance of endothelial self-reorganization prompted by the effect of fluid flow hindrance and facilitation in certain directions. We adopted our previous model of fluid flow guided angiogenesis for cellular responses. Lattice Boltzmann model of fluid flow was adopted and modified to study the effect of unidirectional and randomly oriented fibers. To study the effect of fiber orientation, we customized a previously proposed model of porosity in lattice Boltzmann to suit this purpose. This model could reproduce the effects of fiber orientations in matrix on endothelial migration and vasculogenesis. Simulations showed better confluency of formed lumens when prescribed flow is in the direction of fiber orientation. These results can have further implications in understanding endothelial complications in certain diseases as well as in tumor angiogenesis and metastasis.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
davoud saadati; Sattar Mirzakuchaki
Volume 16, Issue 4 , March 2023, , Pages 61-70
Abstract
Analysis and examination of sound of organs can be utilized in order to diagnose various diseases and abnormal conditions. Diagnostic methods based on audio signal processing are non-invasive and inexpensive and can be especially useful in under-developed countries, where inadequate medical specialists ...
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Analysis and examination of sound of organs can be utilized in order to diagnose various diseases and abnormal conditions. Diagnostic methods based on audio signal processing are non-invasive and inexpensive and can be especially useful in under-developed countries, where inadequate medical specialists and equipment has led to high fatality rates. Development of accessible methods based on machine learning can aid with early diagnosis. we used a convolutional network to attain the advantages of transfer learning. In previous studies, models have been proposed that feed spectrograms with frequency characteristics as inputs to the convolutional network. In this article, we propose a model which additionally employs a recurrent representation (Recurrence plot) that reflects the temporal characteristics of the sound. The audio data sequence is investigated by adding the temporal attention mechanism and the bi-directional recurrent gates for weighting data according to its informational value. Data used in this article is from the ICBHI lung sound database. The presented model was able to classify lung sounds into three categories: healthy, chronic obstructive pulmonary disease (COPD), and other diseases with an accuracy of 97%, which shows the superiority of the proposed method compared to results obtained from previous methods on the same database.
Neuro-Muscular Engineering
Davoud Naderi; Mohsen Sadeghi Mehr; Nader Farahpour; Behnam Miripour-Fard
Volume 2, Issue 2 , June 2008, , Pages 85-93
Abstract
Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response ...
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Cognition of human postural responses can provide valuable insight on the control of stability. Researchers can use this finding to design rehabilitation exercises to improve the patients, balance. This study was done with the aim of conducting theoretical and experimental investigations on human response to tilting base plate in the sagittal plane. A four-segment model with three degrees of freedom was used as a biomechanical model of human body and its motion was studied in the sagittal plane. The postures of model were found by optimization technique such that the stability of model to be optimum. Zero moment point stability criterion was applied to find the optimum posture against the tilting base plate. To verify the theoretical results experimentally, the stability measure device was designed and manufactured. In several trials, the responses of ten male healthy persons standing on a tilting platform under perturbations were recorded by using the motion analysis system. Through data analysis, the response of each subject was surveyed and the experimental and theoretical results were compared. Both the experimental and theoretical results showed that the human central nervous system evokes the ankle strategy to keep its balance under tilting base plate conditions. A good coincident between the experimental results and theoretical predictions was observed, indicating that the model basis optimization method can be well relied upon to predict the human joints angle trajectories in response to base plate tilting.
Cardiovascular Biomechanics
Mehdi Maerefat; Asghar Khoushkar Shalmani; Manije Mokhtari Dizaji
Volume 1, Issue 2 , June 2007, , Pages 95-104
Abstract
Modeling of blood flow and arterial wall in large arteries such as carotid artery, using ultrasonic measurements, allows non-invasive evaluation of clinically interesting homodynamic variables. In this study, a nonlinear mathematical model for the pulsatile arterial flow is proposed using the approximation ...
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Modeling of blood flow and arterial wall in large arteries such as carotid artery, using ultrasonic measurements, allows non-invasive evaluation of clinically interesting homodynamic variables. In this study, a nonlinear mathematical model for the pulsatile arterial flow is proposed using the approximation of “local flow” theory. The blood velocity profile, the pressure gradient and the elastic modulus can be calculated using the model by measuring instantaneous radius and center-line blood velocity. An original mathematical model of pressure gradient in a tapered and elastic tube, using center-line blood velocity, is presented. A Newtonian incompressible Navier-Stokes solver coupled with elastic or visco-elastic arterial wall model is developed to solve the equations of model. The results of modeling and simulation indicate that the approach can estimate the elastic modulus of arterial wall from ultrasonic data. There is a good agreement between the computed arterial wall elasticity and the measured one. The method presented is relatively simple to implement clinically and can be taken as a new diagnostic tool for detecting local vascular change.
Biomedical Signal Processing / Medical Signal Processing / Biosignal Processing
Faride Ebrahimi; Mohammad Mikaili
Volume 4, Issue 2 , June 2010, , Pages 97-108
Abstract
Different biological signals including EEG, EOG, and EMG are recorded in sleep labs to diagnose sleep disorders. Data recorded during sleep is usually analyzed by sleep specialists visually. Since the sleep data is usually recorded for a long time period- namely a whole night- its visual inspection and ...
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Different biological signals including EEG, EOG, and EMG are recorded in sleep labs to diagnose sleep disorders. Data recorded during sleep is usually analyzed by sleep specialists visually. Since the sleep data is usually recorded for a long time period- namely a whole night- its visual inspection and classification is a very demanding and time consuming task so automatic analysis can definitely facilitate that. The key to automatic sleep staging is to extract suitable features. In the current study two classes of features are extracted from EEG signal. The first group is the features calculated from the coefficients of wavelet packet transformation (WPT) and the second group consists of a number of frequency features and a time feature, the amplitude of EEG signal itself. These two sets of features were separately mapped on a two dimensional space by SOM neural networks. The mappings indicated that these features are highly discriminative in separating sleep stages automatically. The data extracted from awake and deep sleep EEGs were mapped on two totally different regions. The mapping also indicated that EEG signal is not enough to separate stages thoroughly, as extracted data from EEG during REM and the first stage of NREM are mapped on the same region. Data extracted from EEG signals in the second stage overlapped with other stages which are in agreement with physiological definition of sleep stages.
Speech processing
Mohammad Bahador Najafi; Mansour Vali
Volume 14, Issue 2 , July 2020, , Pages 97-107
Abstract
After Alzheimer, Parkinson's disease is known as the most common malignant disease of the nervous system. One of the common obstacles of this disease is the expansion of speech disorders. Since the speech production in humans is made by combination of vibration of the vocal cords (phonatory section) ...
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After Alzheimer, Parkinson's disease is known as the most common malignant disease of the nervous system. One of the common obstacles of this disease is the expansion of speech disorders. Since the speech production in humans is made by combination of vibration of the vocal cords (phonatory section) and then passage through the resonator in vocal tract (articulatory section), it is expected that both of these sections to be impaired. In this study, by using a noninvasive method, it is intended to diagnose Parkinson's disease from speech signal of each subject; for this purpose, using 3 sustain vowels in Persian language recorded from 48 people (27 people with Parkinson's disease and 21 healthy people), it has been evaluated to assess the extent of damage to both phonatory and articulatory sections. The phonatory model can include features such as jitter, shimmer, fundamental frequencies, opening and closing cycling time of the glottal pulses. On the other hand, for the articulatory section, features such as first, second, and third formmants, zero crossing rates, MFFCs, and LPC are investigated. In this study, 38 feature categories were extracted and four statistical parameters of mean, standard deviation, skewness and kurtosis were calculated. Genetic Algorithm was used to identify the optimum features. Then, using the SVM, KNN and the Decision Tree classifiers, the optimum extracted features are classified to determine whether a person is patient or healthy. Finally for the main aim of this study, the results of both phonatory and articulatory sections were compared and challenged. The results of this study showed that phonatory features with accuracy of 96.1±1.2% were more useful than articulatory section in diagnosing of Parkinson. Also it was proved that vowel /u/ has more significant role in the diagnosis of Parkinson's disease compared to other vowels by accuracy of 97.6%.
Bioelectromagnetics
Samane Sedighi; Keyvan Keramati; Ali Safari-Varyani; Ahmad Nikpey
Volume 6, Issue 2 , June 2012, , Pages 99-106
Abstract
Exposure to magnetic fields can effect on the learning and memory. The protective effect of saffron extract on memory consolidation disorders in rats exposed to magnetic fields was investigated. 120 male Wistar rats in 12 groups exposed to magnetic field For 5 days with intensity 2.5 tesla for 1, 3 and ...
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Exposure to magnetic fields can effect on the learning and memory. The protective effect of saffron extract on memory consolidation disorders in rats exposed to magnetic fields was investigated. 120 male Wistar rats in 12 groups exposed to magnetic field For 5 days with intensity 2.5 tesla for 1, 3 and 5 hour and protective effects of saffron extract with doses of 125 mg, 200 mg and 300 mg (P ≤0.05) compared to the control group by passive avoidance learning method in shuttle box. One hour exposure with magnetic field had no effect on the rats’ memory consolidation (P ≤0.05). Increase exposure time to 3 and 5 hours had a memory consolidation Impairment compared to the control group (P ≤0.05). Administered rats with 300 mg Inter peritoneal saffron extract improved memory consolidation (P ≤0.05) compared to the control group. Exposure to magnetic fields 2.5 mT, 50 Hz impair memory consolidation. Saffron aqueous extract at a dose of 300 mg per kg may have a protective effect and be improvement consolidation impairments.
Biopolymers
Hadis Bandegani; Saeed Hesaraki; Masoud Alizadeh
Volume 3, Issue 2 , June 2009, , Pages 99-109
Abstract
The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate ...
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The aim of the present paper is to investigate the effect of incorporating various amounts of strontium ions (0.19 - 2.23 wt%) into calcium sulfate bio ceramics on the physical, structural properties and in vitro bioactivity and compare these properties with those of a pure calcium sulfate dehydrate (gypsum) as control. Strontium-doped gypsum (Sr-gypsum) was obtained by mixing calcium sulfate hemihydrates powder and solutions of strontium nitrate followed by washing the specimens with distilled water for the removal of residual salts. Gypsum was the only phase found in the composition of both pure and Sr-gypsum meanwhile a shift into lower diffraction angles was observed in the x-ray diffraction patterns of doped specimens. The Sr-doped sampled exhibited higher compressive strength and lower solubility than pure gypsum. Microstructure of all gypsum specimens had been composed of many rod-like small crystals entangled to each others with more elongation and higher thickness in the cases of Sr-gypsum. EDXA pattern of Sr-gypsum showed the presence of calcium and sulfur ions as the main elements of gypsum as well as slight amount of strontium ion. A continuous release of strontium was observed from the Sr-gypsum after soaking in simulated body fluid for 14 days. Proliferation rate of cultured osteoblasts and higher alkaline phosphatase activity on doped samples was better compared to pure gypsum.
Bioelectromagnetics
Reza Masoomi Jahandizi; Parviz Abdolmaleki; Seyed Javad Mowla
Volume 5, Issue 2 , June 2011, , Pages 105-115
Abstract
The effect of 15 and 30 mT of static magnetic field on the cell cycle of neural inductive rat BMSC was evaluated. The BMSC was inductived by neural inductive medium (NIM). Duration of inductive and Exposure time were 2, 4 and 6 hours. The cells induction to neural inductive medium associated with SMF ...
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The effect of 15 and 30 mT of static magnetic field on the cell cycle of neural inductive rat BMSC was evaluated. The BMSC was inductived by neural inductive medium (NIM). Duration of inductive and Exposure time were 2, 4 and 6 hours. The cells induction to neural inductive medium associated with SMF as exposed group, besides we have a control group. The apparatus we used to generate the SMF was a locally designed SMF generator in which there was an incubator instrument capable to maintain the humidity, temperature and CO2 concentration in predefined level. After exposing, the cells were fixed, stained and their percent of cell cycle phases; G1, S, G2/M were elucidated using flowcytometer instrument. The WinMdi 2.9 Software was used to process data from flowcytometer and elucidation of phase's percents. The results showed SMF with 15 mT intensity did not significantly alter the cell cycle in three different (2, 4 and 6 hours) exposing times. Exposing 2 hours with 30 mT increased the G2/M phases in neural inductive BMSC comparing to the corresponding control. Static magnetic field decreased the percent of S phase in BMSC, during 4 hours exposure.
Neural Network / Biological & Artificial Neural Network / BNN & ANN
Hamed Abbasi; Shahrokh Shojaei; Nasim Naderi
Volume 13, Issue 2 , August 2019, , Pages 105-115
Abstract
Today, in order to decide on many cardiac surgeries, and whether the patient is able to get under surgery or the time of surgery is passed, it is necessary to measure pulmonary vascular resistance and if the resistance is above a threshold, the patient is considered to be non-surgery; and sometimes, ...
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Today, in order to decide on many cardiac surgeries, and whether the patient is able to get under surgery or the time of surgery is passed, it is necessary to measure pulmonary vascular resistance and if the resistance is above a threshold, the patient is considered to be non-surgery; and sometimes, some therapies are used to reduce the resistance of the pulmonary arteries to the initial disease of the arteries, in which, in order to track down the resistance of the pulmonary vascular, a re-measurement of this parameter is required. Currently, the golden standard of this measure is the use of catheterization procedures, which are aggressive and associated with complications. The purpose of this study is to replace a non-invasive method, rather than an invasive method of cardiac catheterization, by predicting pulmonary vascular resistance based on echocardiographic data by artificial neural networks. Research was performed on 591 patients. Echocardiography was recorded for all subjects, and the echocardiographic data (mPAP, dPAP, sPAP, PCWP, CO) as the neural network input and pulmonary vascular resistance of all patients who were subjected to previous catheterization was evaluated as the output of the neural network and thus, it was obtained, the relationship between echocardiography data and PVRcath. The proposed neural network was typically learned with 75% of the data, and was tested with 25% of the data, and these ratios were modified to better learn the neural network. As a result of implementation, the mean squared error, respectively, for the learning and testing data for the proposed neural network, was 0.37 and 0.27 for the first model, 14.67 and 10.76 for the second model, and 15.82 and 9.58 for the third model.
Fluid-Structure Interaction in Biological Media / FSI
Saeed Nahidi; Alireza Hossein-Nezhad; Nasser Fatouraee; Zahra Heidari
Volume 7, Issue 2 , June 2013, , Pages 107-120
Abstract
Blood flow parameters are affected by position and shape of the accumulation of low density lipoprotein (LDL) in the layers of the arterial wall, and this phenomenon itself is influenced by infiltration flow of the blood. In this paper, in order to investigate the effect of wall flexibility on the infiltration ...
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Blood flow parameters are affected by position and shape of the accumulation of low density lipoprotein (LDL) in the layers of the arterial wall, and this phenomenon itself is influenced by infiltration flow of the blood. In this paper, in order to investigate the effect of wall flexibility on the infiltration flow in a pulsatile non-Newtonian blood flow in a symmetric carotid artery stenosis with a two flexible and porous layers, a finite element model with Porous Fluid Structure Interaction (PFSI) method was used and the results were compared to the porous rigid model. Study parameters were investigated in three different stenosis severities. Comparison of the presented results using PFSI model with those of Porous Rigid model showed about 22% decrease in wall shear stress in the stenosis region, about 20% increase in filtration velocity in the pre- and post-stenosis regions of the porous layer, but a slight difference in filtration velocity in the stenosis region.
Medical Robotics / Bio-Robotics
Mahya Salem; Saeed Ebrahimi; Mehdi Bamdad
Volume 11, Issue 2 , June 2017, , Pages 111-125
Abstract
In this study, a portable upperlimb exoskeleton is designed for the purpose of rehabilitation and helping the disabled people to do their daily activities. This exoskeleton has two active and one passive degrees of freedom for the shoulder joint. In this system, the idea of cable transmossiom mechanism ...
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In this study, a portable upperlimb exoskeleton is designed for the purpose of rehabilitation and helping the disabled people to do their daily activities. This exoskeleton has two active and one passive degrees of freedom for the shoulder joint. In this system, the idea of cable transmossiom mechanism and guidance pulley with the ability to change the force direction is used. The two active DOFs of the shoulder joint is achived only by pulling one cable for each axis based on the novel design of this mechanism. Each axis of the shoulder is driven independently which implies that a single axis can be installed on the arm. This exoskeleton does not impose any limitation on the vertical motion of the scapula. In addition, it is inexpensive, lightweight and can easily be used. In this paper, after introducing the exoskeleton system, the required motor torques for generating a prescribed task are obtained. In the next step, the kinematic and dynamic equations of this system are derived. By simulating the exoskeleton in CATIA and MATLAB softwares, and presenting the results, the performance of the exoskeleton is evaluated. The results show that this novel exoskeleton system posses an excellent capacity to perform the rehabilitation excersises for shoulder joint.
Biomedical Image Processing / Medical Image Processing
Somayeh Maleki Balajoo; Davoud Asemani; Hamid Soltanian-Zadeh
Volume 12, Issue 2 , September 2018, , Pages 111-124
Abstract
Early alterations of functional connectivity (FC) within the default mode network (DMN) have been reported in Alzheimer’s disease (AD). Recently, the resting-state brain networks have been described with non-stationary profiles since inter- and intra-FC of the brain networks changes over time, ...
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Early alterations of functional connectivity (FC) within the default mode network (DMN) have been reported in Alzheimer’s disease (AD). Recently, the resting-state brain networks have been described with non-stationary profiles since inter- and intra-FC of the brain networks changes over time, even at rest. To fully understand the FC changes that characterize AD, the underlying change of its dynamic pattern needs to be captured. The purpose of this study was to evaluate dynamic FC (dFC) patterns within the DMN in patients with AD relative to healthy aging. Here, a sparse logistic regression (SLR) model was employed to estimate the dFC networks in patients with AD (n = 24) compared with healthy control group (n = 37) using resting-state functional magnetic resonance imaging (rs-fMRI) data. To analyze the dFC network, we introduced a temporal variability-functional pattern (TV-FP) score, which shows how the functional pattern of a given region changes over time. This score is able to quantify the temporal patterns of regions involved in a dFC network. We compared TV-FP score across groups. The results indicate that the main regions of DMN, such as the anterior medial prefrontal cortex (aMPFC) and lateral temporal cortex (LTC), are associated with a significantly increased TV-FP score in the AD group when compared to the HC group. The FC pattern of these regions is impaired in AD according to a conventional static functional connectivity (sFC) analysis. These findings may suggest that aMPFC and LTC may tend to reorganize their functional pattern to compensate for the related functional deficiency due to AD.
Computational Neuroscience
Maryam Moghadam,; Farzad Towhidkhah; Golnaz Baghdadi
Volume 15, Issue 2 , August 2021, , Pages 111-125
Abstract
In cognition physiology and neuroscience, spatial memory is responsible for the maintenance and recall of information related to environmental details, orientation, and spatial navigation. The brain’s cognitive functions including navigation are executed through correlated and sequential activities ...
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In cognition physiology and neuroscience, spatial memory is responsible for the maintenance and recall of information related to environmental details, orientation, and spatial navigation. The brain’s cognitive functions including navigation are executed through correlated and sequential activities of different regions. According to previous research, navigation is largely related to the activities of the Hippocampus (HPC) and the Medial Temporal Lobe (MTL), and retrieval of spatial memories from these regions is controlled by the frontal region and specifically medial prefrontal cortex (mPFC). In this paper we attempt to provide a navigation cognitive model based on computational concepts focusing on bidirectional interaction between HPC and mPFC. This model is provided considering 1. The lack of a comprehensive cognitive model of navigation on a previously learned path and ambiguities regarding the information transferring between the regions, and 2. Disagreement between available models and the currently known actual information flow occurring within the brain. The model is inclusive of the active brain regions engaged in navigation using the cognitive map. Furthermore, we propose a computational model based on van-der-pol neuron pools and controlling rule-base, which is naturally related to the actual brain activity through the synchrony mechanism for information transfer and the mPFC rule-based control of the medial temporal lobe. Finally, by analyzing and presenting evidence, we have shown that the model can be beneficial and practical for describing cognitive and functional disorders in navigation, also for design and prediction of the outcomes of therapeutic and rehabilitation protocols in diseases related to spatial navigation, such as the Alzheimer’s disease.
