Maryam Parviz; Mohammad Rabiee; Mohammad Ali Shokrgozar; Fathollah Moztarzadeh; Farzad Yousefi Gharebaghi; Mahdis Shayan; Mohammad Reza Tahriri
Volume 3, Issue 2 , June 2009, , Pages 89-97
Abstract
A great deal of attention has been drawn to the colloidal chemistry based semiconductor nanocrysallites, also known as quantum dots (QDs). Because of the strong quantum confinement, quantum dots have unique size-dependent optical properties, which are much more superior to the conventional organic fluorescence ...
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A great deal of attention has been drawn to the colloidal chemistry based semiconductor nanocrysallites, also known as quantum dots (QDs). Because of the strong quantum confinement, quantum dots have unique size-dependent optical properties, which are much more superior to the conventional organic fluorescence materials. In addition, strong chemical resistant makes inorganic semiconductor QDs an ideal candidate for next-generation of bio-labels and other biomedical applications. This study presents a synthesize method of high quality biocompatible CdSe QDs in aqueous solution by using gelatin as inhibitor. A thin ZnS layer was grown on CdSe QDs, forming a CdSe/ZnS core/shell structure, to improve the photoluminescence. The optical properties of the QDs were characterized by photoluminescence spectra. The stability of CdSe/ZnS QDs in aqueous solution has been improved with capping in mercaptosuccinic acid (MSA) groups. PAGE test results show that carboxylic groups of MSA have interacted with NH2 agent of CD20 antibodies. We evaluate the in vitro efficiency of the luminescence of the bioconjugated QDs to kill Raji cells. Raji cells have anti-CD20 which can especially connect to CD20-QDs. In conclusion, we found that CD20-CdSe/ZnS bioconjugated QDs with different concentration 50-250 µg/mL which have been exited at 400nm in 2h intervals can result in Raji cells death. This study shows the potential of CdSe/ZnS for cancer treatment.
Bioelectromagnetics
Maryam Sadri; Parviz Abdolmaleki; Saeed Abroun; Bahare Beiki; Fazel Samani
Volume 6, Issue 2 , June 2012, , Pages 91-98
Abstract
The Mesenchymal Stem cells derived from human newborn cords were cultured and exposed to a 24mT Static magnetic field for 24 hours. The viability percentage and the cell cycle progression was then investigated in exposed samples and the obtained results was compared with the control samples. The results ...
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The Mesenchymal Stem cells derived from human newborn cords were cultured and exposed to a 24mT Static magnetic field for 24 hours. The viability percentage and the cell cycle progression was then investigated in exposed samples and the obtained results was compared with the control samples. The results clearly demonstrated a significant reduction of cell viability due to the exposure of 24 hours of SMF and post-exposure cultures within the time frames of 36,48,60 hours. The cell development through the cell-cycle, also verified this finding, however, 72 hours of post-exposure culture, significantly leveled off the drop in viable stem cell rates.
Seyedeh Saeideh Zahedi Haghighi; Sayed Mahmoud Sakhaei; Mohammadreza Daliri
Volume 13, Issue 2 , August 2019, , Pages 95-104
Abstract
Emotion is one of the most important human quality that plays an important role in life. Also, one way of communicating between human and computer is based on emotion recognition. One way of emotion recognition is based on electroencephalographic signal (EEG). In this paper, according to the non-stationary ...
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Emotion is one of the most important human quality that plays an important role in life. Also, one way of communicating between human and computer is based on emotion recognition. One way of emotion recognition is based on electroencephalographic signal (EEG). In this paper, according to the non-stationary property of EEG, intrinsic mode functions (IMF) extracted by using empirical mode decomposition (EMD) and then first 3 IMFs selected. Each IMF converts into smaller pieces with a one-second window and power feature has been extracted from each piece. Then, by using a suitable mapping, the position of the electrodes in the 10-20 system becomes the position of the pixels in the picture. The extracted features are considered as pixel color components. To determine the class of valence, the set of all generated pictures is given as input to a deep learning network and output determine the high or low class of valence. The same process is used to determine the class of arousal. To examining the method, the DEAP dataset is used. By choosing 17×17 for the image size, the mean accuracy and standard deviation were obtained of 78.58% and 3.9 for the valence and 78.66% and 3.1 for the arousal which that shows a significant improvement compared to similar tasks.
Biomedical Image Processing / Medical Image Processing
Sina Shamekhi
Volume 16, Issue 2 , September 2022, , Pages 95-113
Abstract
Intuitive examination of retinal layers in Spectral-Domain Optical Coherence Tomography (SD-OCT) images is one of the main methods used by physicians to diagnose retinal diseases. This method faces challenges such as noise and image complexity and the proximity of retinal layers. In recent years, the ...
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Intuitive examination of retinal layers in Spectral-Domain Optical Coherence Tomography (SD-OCT) images is one of the main methods used by physicians to diagnose retinal diseases. This method faces challenges such as noise and image complexity and the proximity of retinal layers. In recent years, the automatic diagnosis of retinal diseases has become an important clinical issue in computer vision. In this research, a new method for efficient multi-class automatic classification of SD-OCT images has been proposed. This method consists of five stages, preprocessing, layer recognition, feature extraction, and image classification. Examination of the shape of the RNFL layer and IS/OS junction as a clinical method is influential in physicians' decisions to diagnose retinal diseases. Therefore, in this study, inspired by this clinical diagnosis method, the RNFL layer, and the IS/OS junction have been detected by a new method based on the Frangi vessel enhancement algorithm and the gradient of the image. Then, by extracting and selecting several efficient features from the curves of the layers, an algorithm based on the ensemble decision tree has been proposed for classifying SD-OCT images of the retina and presented as a MATLAB application. The proposed method has been evaluated using images of two well-known databases of Duke and Kermany. Based on the results, precision, sensitivity, specificity, accuracy, miss rate and F1-score of the proposed method in Duke database were equal to 98.7, 98.8, 99.4, 99.1, 1.3, and 98.7, respectively, and in Kermany database were 96.8, 96.7, 98.9, 98.4, 3.2 and 96.7 respectively. The results show the superiority of the proposed method compared to other comparative methods. In summary, the use of efficient features of retinal effective layers and a powerful algorithm for classification has improved the performance of the proposed method compared to previous more complex methods.
Biomimetics
Mohammad Reza Nikmaneshi; Bahar Firoozabadi; Mohammad Saeid Saeidi
Volume 7, Issue 2 , June 2013, , Pages 97-105
Abstract
The front part of a cell is divided to two regions called lamellum and lamellipodium (lamellipodial). Internal flows in this part plays an essential role for cell migration. Indeed, there are many protein filaments called actin in lamellum and lamellipodium, which induce the cell motion with polymerization ...
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The front part of a cell is divided to two regions called lamellum and lamellipodium (lamellipodial). Internal flows in this part plays an essential role for cell migration. Indeed, there are many protein filaments called actin in lamellum and lamellipodium, which induce the cell motion with polymerization in the leading edge of the cell. The actin filaments adhere to the extracellular matrix (ECM) by means of focal adhesions and they have contact by myosin motor proteins. The myosin motor proteins cause actin retrograde and anterograde flow exerted contractile stress on them. The focal adhesions exert frictional stress on the actin filaments. In this work, we developed a two-dimensional continuum model of the fanshaped lamellipodial to obtain the actin retrograde flow. In addition, the actin filaments are assumed as a highly viscous Newtonian fluid. We also investigated the effects of the myosin distribution and cell speed on the actin flow. Our results include actin flow and myosin distribution in the moving cell, and we also illustrate their relation together. These results accord to reported experimentally and numerically data, and are verified with them.
Brain Computer Interface / BCI / Neural Control Int. / NCI / Mind Machine Int. / MMI / Direct Neural Int. / DNI / Brain Machine Int. / BMI
Fatemeh Ghomi; Amin Mahnam; Mohammad Reza Yazdchi
Volume 12, Issue 2 , September 2018, , Pages 97-109
Abstract
Over the past few decades, the brain-computer interfaces (BCI) based on motor imagery has been widely developed to help people with motor disability. The advantage of this type of BCI as an endogenous system is, no need for external stimulation, and natural control. One of the major challenges to make ...
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Over the past few decades, the brain-computer interfaces (BCI) based on motor imagery has been widely developed to help people with motor disability. The advantage of this type of BCI as an endogenous system is, no need for external stimulation, and natural control. One of the major challenges to make these systems practical is to reduce the number of recording electrodes. In this study, only two EEG channels (C3 and C4) were used for detecting the imagery of left and right-hand movements. The features used were band powers (BP), some time domain parameters (TDP) and an adaptive autoregressive model (AAR). For classification, linear discriminant analysis (LDA), a well-known and simple classifier was used.The data was taken from the third BCI Competition. Our results confirm that BP features provide the most robust and effective features for accurate recognition. It was shown that combining the BP with TDP and AAR features can improve the accuracy of classification. However, implementing BP and TDP features is proposed for online classification where short computational cost is important. A maximum steepness of the mutual information (STMI) of 0.2582 was achieved in this study that could win the second place in the BCI Competition III. Left and right motor imagery (MI) tasks can be discriminated with an average classification accuracy of 85% and Kappa of 70%.
Biological Computer Modeling / Biological Computer Simulation
Fateme Pourhasan Zade; Seyed Hojat Sabzpoushan; Ali Mohammad Alizade; Ebrahim Esmati
Volume 10, Issue 2 , August 2016, , Pages 99-112
Abstract
Cancer is the third leading cause of death in Iran after cardiac diseases and car accidents. Mathematical and computational models are great help to better understand cancer related phenomena. It may even improve common therapies or introduce new therapies. In this paper, a new multiscale cellular automata ...
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Cancer is the third leading cause of death in Iran after cardiac diseases and car accidents. Mathematical and computational models are great help to better understand cancer related phenomena. It may even improve common therapies or introduce new therapies. In this paper, a new multiscale cellular automata model of tumor growth based on the tumor micro-environment is introduced. Two separate square lattices are presumed for metabolic and cellular spaces. One of the following four states can be devoted to each cell in the cellular lattice: proliferating cancer, non- proliferating cancer, necrotic, and normal cells. Changing the cell's state and tumor growth is discussed in this lattice. However, production/consumption, and the diffusion of nutrients (oxygen and glucose) and also waste products including lactic acid are studied in the metabolic lattice. In this study, we determined the stochastic rules of altering the states of each cell based on the concentration rates of nutrients and lactic acid. The growth fraction and necrotic fraction were used as output parameters beside a 2-D graphical display of growth. The changes in the level of nutrients in the metabolic lattice and the effect of acidity on the growth of tumor have been reported in this paper. Our simulations faithfully reproduce the in vivo experimental observations reported for cholangiocarcinoma.
Biomimetics
Yasaman Amiri,; Bahman Vahidi
Volume 15, Issue 2 , August 2021, , Pages 99-110
Abstract
Microneedles are a type of micron-sized needle that is the third most widely used delivery system after oral and injectable drug delivery, used in a variety of fields including drug release and rejuvenation. Optimizing the geometry of microneedles to reduce pain and inflammation has been important in ...
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Microneedles are a type of micron-sized needle that is the third most widely used delivery system after oral and injectable drug delivery, used in a variety of fields including drug release and rejuvenation. Optimizing the geometry of microneedles to reduce pain and inflammation has been important in recent years. Due to the high cost of microneedle fabrication, numerical simulation of microneedle penetration into the skin can be useful to evaluate the microneedle strength as well as its effect on the skin during penetration. In this study, first a new simulation method in Abaqus software with explicit method using cohesive elements to investigate the penetration of microneedles in the skin of the human forearm was presented. The skin was considered as Ogden and bilayer hyperelastic models. The microneedle was considered as a rigid body and a constant velocity of 0.6 mm/s was applied to it .The microneedle with bulk with bio-inspired titles was examined and its important parameters such as height, sharpness and bulk angle were evaluated. Finally, some proposed models of microneedles with longitudinal grooves are presented to increase the concentration of stress on the skin and prevent friction. A comparison of the designed microneedle with the barbless microneedle shows that the barbed microneedle concentrates more than twice as much stress on the skin, but reduces the penetration force by as much as 15%, making it easier to penetrate the skin. The results show that the reduction longitudinal grooves increase the tension created in the skin by about 10%, but have little effect on the penetrating force on the skin.
Biological Systems Modeling
Hossein Banki-Koshki; Seyyed Ali Seyyedsalehi
Volume 17, Issue 2 , September 2023, , Pages 100-110
Abstract
Neuronal synchronization as a significant cognitive phenomenon of the human brain, has attracted the interest of neuroscience researchers in recent years. This phenomenon is generally investigated in discrete and continuous neuronal models or experimentally recorded signals of the brain. In this study, ...
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Neuronal synchronization as a significant cognitive phenomenon of the human brain, has attracted the interest of neuroscience researchers in recent years. This phenomenon is generally investigated in discrete and continuous neuronal models or experimentally recorded signals of the brain. In this study, for the first time, we investigate the weight synchronization instead of neuronal synchrony, in the training step of the artificial feedforward neural networks. The findings of the study show that the generalized weight synchronization occurs both during the training mode and in the non-training mode. Furthermore, as the training is completed, the synchronization increases between the weights. In this study, a new method is introduced in order to detect synchrony patterns using signal derivative and hierarchical clustering. We have also presented a criterion to quantify weight synchronization in different layers of the neural network. Accordingly, the results demonstrate that the lower layers of the network have a significantly higher level of weight synchrony than the upper layers.
Human Computer Interaction / HCI
Sahar Sadeghi; Ali Maleki
Volume 11, Issue 2 , June 2017, , Pages 101-109
Abstract
To increase the number of stimulation frequencies in the Steady-state visual evoked potential (SSVEP)-based brain-computer interface, we are forced to broaden the frequency range due to the frequency resolution restriction. This will enter frequencies with harmonic relation into the stimulation frequency ...
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To increase the number of stimulation frequencies in the Steady-state visual evoked potential (SSVEP)-based brain-computer interface, we are forced to broaden the frequency range due to the frequency resolution restriction. This will enter frequencies with harmonic relation into the stimulation frequency range and lead to increase in frequency recognition error. In this paper, a three-stage method including the empirical mode decomposition (EMD), the canonical correlation analysis (CCA) and neural network classifier has been proposed that can solve the recognition error problem for wide frequency range including frequencies with harmonic relation. Visual stimulus ranged from 6-16 Hz with an interval of 0.5 have been generated using Matlab and the psychophysics toolbox. The SSVEP signal was recorded from ten subjects via one electrode placed at Oz. After extracting the intrinsic mode functions (IMFs) of the signal by EMD and reconstructing the combined signals, the CCA has been applied. Two features including the detected frequency and the correlation value in this frequency have been extracted and they were given to the neural network classifier. For eight-second time window, the average accuracy of the CCA for N=1 was 78% and for N=2 was 74%, while the corresponding values of the proposed method were 82% and 77% respectively. For four-second time window, the accuracy was increased from 78% to 83% for N=1 and it was increased from 78% to 80% for N=2. N is the number of harmonics in the generation of the reference signal in the CCA. For wide frequency range, the proposed method has been able to improve the frequency recognition accuracy compared to the standard CCA method. according to this, by broadening the stimulation frequency range, the possibility of increasing the number of frequency options and thus increasing the information transfer rate are provided.
Biological Computer Modeling / Biological Computer Simulation
Zohre Barani; Mohammad Haghpanahi; Hamid Reza Katouzian; Hasan Saeidi
Volume -1, Issue 2 , June 2005, , Pages 111-116
Abstract
Current research in foot biomechanics includes studies on prevention of recurrence of neuropathic foot ulcers. This prescribes accommodative insoles, which reduce plantar pressure levels particularly under the hallux. There is little quantitative information available regarding the effects of insole ...
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Current research in foot biomechanics includes studies on prevention of recurrence of neuropathic foot ulcers. This prescribes accommodative insoles, which reduce plantar pressure levels particularly under the hallux. There is little quantitative information available regarding the effects of insole materials. The insole models available in the literature are mostly two- dimensional (2-D). Hence, there is a need to develop a three-dimensional (3-D) model with actual geometry which includes sufficient details. In this study a 3-D model of the insole was constructed. A linear and non-linear static analysis using finite element method (FEM) was done. To construct the 3-D finite element model, 14736 nodes and 16170 elements were used. This research has shown that Silicone Gel is very effective in terms of reduction of stress concentrations. The techniques used in this research provide a promising approach to understand the behavior of insole material as well as a guideline in the design of therapeutic footwear and orthoses for insensate feet.
Biomedical Image Processing / Medical Image Processing
Leila Azimi; Nader Riahi Alam; Kavoos Firuozniya; Hamid Reza Saligheh Rad; Mojtaba Miri; Manizheh Pakravan; Anamollah Shahmohammadi
Volume 8, Issue 2 , June 2014, , Pages 113-123
Abstract
Gliomas are the most common primary neoplasm of the brain, varying histologically from low grade to high-grade. Perfusion-weighted MRI techniques have permitted the creation of cerebral blood volume (CBV) value, leading to the qualitative and quantitative assessment of tumor vascularity. This research ...
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Gliomas are the most common primary neoplasm of the brain, varying histologically from low grade to high-grade. Perfusion-weighted MRI techniques have permitted the creation of cerebral blood volume (CBV) value, leading to the qualitative and quantitative assessment of tumor vascularity. This research aimed at assessing the rCBV and the ADC values in core and peritumoral areas glioma brain tumors and determining of significance rCBV of values i Alpha I In evaluating brain tumor. Ten patients with non-enhancing supratentorial gliomas were evaluated by diffusion weighted imaging (DWI) and standard dynamic susceptibility contrast-enhanced gradient echo during first pass of a bolus injection of contrast material before surgical resection. Six low-grade gliomas (WHO Grade II) and 4 high-grade gliomas (III, IV) were evaluated. Alpha Both the apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) values were calculated by a standard program on the solid portion of the tumor in the peritumoural area as well as contra lateral white matter. In perfusion, mean rCBVmax in high-grade and low-grade tumors were obtained (3.47±0.92), (2.37±0.49)-(1.66±0.68), (1.15±0.39) for core and peritumoral regions, respectively. In diffusion method, mean ADC in high-grade and low grade tumors were (0.53±0.07), (0.91±0.18)-(1.24±0.27), (1.007±0.33) for core and peritumoral regions, respectively. It was concluded that the values rCBVs are important in determining the grade of tumor and we propose that perfusion weighted imaging be done for all patients before surgery.
Biomedical Image Processing / Medical Image Processing
Fariborz Mahmoudi; Faraein Aeini
Volume 9, Issue 2 , July 2015, , Pages 113-131
Abstract
Due to teeth robustness, uniqueness and availability of medical records, today a new branch of research for human identification is ongoing based on dental radiograph images. This method of identification has particular importance especially in events such as wars, fires, tsunamis and other similar events ...
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Due to teeth robustness, uniqueness and availability of medical records, today a new branch of research for human identification is ongoing based on dental radiograph images. This method of identification has particular importance especially in events such as wars, fires, tsunamis and other similar events with other biometrics features heavily damaged. In this article also a framework for human identification based on dental characteristics is proposed. The proposed framework consists of two stages: the first stage is teeth classification and numbering, and the second stage is teeth recognition. In this study, a new feature has been proposed for each of these two stages: Crown mesiodistal neck and anatomic crown length for the first and weighted sampling of teeth contours for the second. The proposed method is capable to solve principally and automatically problems such as diagnosis of posterior teeth, posterior teeth classification, diagnosis of number and kind of pulled teeth, which are overlooked or have been left with the simple premises in previous works. To evaluate the proposed method, experiments on a set of bitewings, periapical and panoramic images are done. The practical results show an improvement of 8% in accuracy of classification and numbering, and also 27% improvement in accuracy of teeth recognition, in comparison with the preceding works
Biomedical Image Processing / Medical Image Processing
Nader Riahi Alam; Reza Aghaeizade Zoroofi; Masoume Giti; Arian Deldari; Alireza Ahmadian
Volume 1, Issue 3 , June 2007, , Pages 157-165
Abstract
In this study, the need of a CAD system and its capabilities has been investigated and then a sample program for a mammographic CAD system proper to Iranian tropical patients was designed. In the first step, the analog mammographic images were digitized by 56 and 112 mm spatial resolution and then were ...
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In this study, the need of a CAD system and its capabilities has been investigated and then a sample program for a mammographic CAD system proper to Iranian tropical patients was designed. In the first step, the analog mammographic images were digitized by 56 and 112 mm spatial resolution and then were processed by the designed sample program. Analysis and technical details for designing and implementing the program included for following steps: The capability of the program image displayer consisting of viewing four mammographic images from four breast views (RCC, RMLO, LCC, LMLO) in one window, determining breast region by background removing and other conventional preprocessing application tools; Software processing tools including theresholding, histogram, ROI determination; Patient information fields such as clinical information, conventional reporting section as used in radiological department in Iran; Computer-aided diagnostic section including proper diagnostic processing algorithm to automatic detection of breast abnormality. For instance the application of wavelet and fuzzy logic for detecting malignant clusters of microcalcification. The introduced mammographic CAD system can provide the collection, organizing and the availability of the patient local information. Therefore by using the prepared database the evaluation of the sensitivity and specifity of the detecting algorithm for comparison of different research methods would be possible.
Nano-Biomaterials
Shekufe Borhan; Saeed Hesaraki
Volume 6, Issue 3 , June 2012, , Pages 163-168
Abstract
Bioactive glasses with different compositions have been extensively used as substitute for defective bones. Injectable biomaterial is important in clinical applications that involve defects with limited accessibility or when using minimally invasive surgical techniques. In this study bioactive glass ...
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Bioactive glasses with different compositions have been extensively used as substitute for defective bones. Injectable biomaterial is important in clinical applications that involve defects with limited accessibility or when using minimally invasive surgical techniques. In this study bioactive glass nano-powder was synthesized by acid-base catalyzed sol-gel process and used as solid phase of injectable non-setting pastes. Morphological characteristics of powder were found by TEM. To prepare paste the powder was mixed with hyaluronic acid and polyvinyl alcohol solutions. Stability of pastes was determined by soaking in simulated body fluid. Rheological behaviours of paste in both rotation and oscillation modes were also measured. The results showed that particle size of glass powder was 20-30 nm. According to rheometry, these nano composites exhibited non-Newtonian shear thinning behaviour. By adding polyvinyl alcohol more stable paste with increased hysteresis loop area is obtained. The oscillatory tests revealed that these pastes were viscoelastic with more elastic character. The biocomposite can potentially be used as bioactive paste for the treatment of hard and even soft tissues.
Biological Computer Modeling / Biological Computer Simulation
Fereshte Yousefi Rizi; Alireza Ahmadian; Javad Alirezaie; Emadoddin Fatemizadeh; Nader Rezaei
Volume 2, Issue 3 , June 2008, , Pages 165-177
Abstract
Partial volume effect and image noise greatly decrease the visibility of the airway wall. Another dilemma with airway segmentation methods, which significantly influences their accuracy, is the leakage into the extra-luminal regions due to thinness of the airway wall during the process of segmentation. ...
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Partial volume effect and image noise greatly decrease the visibility of the airway wall. Another dilemma with airway segmentation methods, which significantly influences their accuracy, is the leakage into the extra-luminal regions due to thinness of the airway wall during the process of segmentation. A solution to this problem in the previous methods was based on leak detection and reduction by adjusting the segmentation parameters and performing the whole segmentation process, which is very time consuming and demands user interaction. The new strategy presented here is to prevent the leakage by taking the advantage of the fact that the airway branches are cylindrically shaped objects. This has been achieved by introducing a new mathematical shape optimization approach embedded in FC-FCM algorithm to retain the cylindrical properties of the airway branches during the segmentation process. The main role of this optimization approach is to detect and correct the underlying voxels which belonging to the airway by satisfying both conditions of the fuzzy connectivity and shape features. The proposed FC-FCM algorithm was first applied on four data sets each containing 430 CT images of CT images of airway tree. The result showed an accuracy of 93% obtained for segmentation of the airway tree up to the fourth generation. We then applied OPT-FC-FCM algorithm to segment the airway tree with optimization process up to the sixth generation of airway. The result proves the ability of our proposed method to complete a visually acceptable segmentation of airway trees with no leakage. The number of detected branches was found 65 (4 times of those obtained by using just the FC-FCM method).
Rehabilitation Engineering
Robabe Vatanparast; Hossein Karimi; Fariba Bahrami; Roya Narimani
Volume 3, Issue 3 , June 2009, , Pages 171-178
Abstract
CNS applies Anticipatory Postural Adjustments (APA) strategy to reject or minimize perturbation during different voluntary movements. The postural control mechanisms associated with voluntary arm movement (rapid arm rising) in below knee amputees (BKA) was investigated and the results were compared with ...
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CNS applies Anticipatory Postural Adjustments (APA) strategy to reject or minimize perturbation during different voluntary movements. The postural control mechanisms associated with voluntary arm movement (rapid arm rising) in below knee amputees (BKA) was investigated and the results were compared with the normal subjects. Biomechanical variables including ground reaction forces and displacements of the center of pressure were used to investigate the APA in BKA. Six below knee amputees and six control subjects stood on a force plate under three conditions: 1. with both feet on the platform, 2. with right foot (prosthetic foot) and 3. with left foot on the plate. For each condition, the task was repeated 10 times. At the same time, a camera recorded the task performance. The recorded data were used to determine the start moment of the movement. The instant at which, for the first time before starting the movement, any one of the recorded biomechanical variables deviated from its initial value was considered as the beginning of the APA. To increase the validity of the test, efforts were made to match the subjects with regards to their age, gender, cause of amputation and prosthesis types. Our results indicated that the center of pressure in the BKA participants showed greater displacements in medial-lateral and anterior-posterior directions. It was also observed that the vertical components of the ground reaction forces, when the right foot was on the plate, were increased. There were no significant differences in other biomechanical variables between the two groups. We may conclude that the voluntary arm movement perturbs the posture in the BKA participants more than in the control group. The BKA participants shifted their weight to the intact limb by the anticipation of the disturbance to avoid balance loosing. Therefore, in our study the intact limb in below knee amputee subjects played an important role in the balance control. Based on our results, we suggest considering the role of the intact limb in the rehabilitation programs and strengthening the muscles of both limbs as a major part of theses programs.
Faraein Aeini; Alireza Ghonoodi; Rashin Aeini
Volume 12, Issue 3 , November 2018, , Pages 173-187
Abstract
Forensic dentistry is the subdivision of forensics that determines the identity of the victim based on dental features. In this paper, we propose a framework for human identification based on dental. The proposed framework consists of two main stages: the first stage is teeth classification and numbering, ...
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Forensic dentistry is the subdivision of forensics that determines the identity of the victim based on dental features. In this paper, we propose a framework for human identification based on dental. The proposed framework consists of two main stages: the first stage is teeth classification and numbering, and the second stage is human recognition. In this study, a new feature has been proposed for each of these two stages: Crown mesiodistal neck and anatomic crown length for the first and a feature vector based on the geodesic distance between important points of teeth contours for the second. The proposed method is capable of solving principally, and automatically problems such as diagnosis of posterior and also anterior teeth, posterior and anterior teeth classification, diagnosis of number and kind of all kind pulled teeth from, which are overlooked or have been left with the simple premises in previous works. To evaluate the proposed method, we experiment on a set of bitewings, periapical and panoramic images. The practical results show an improvement in accuracy of classification with discovering anterior teeth, and also 9% improvement in the first rank of the accuracy of teeth recognition, in comparison with the previous works.
Biomechanical Motor Control / Motor Control of Human Movement
Hamed Ghomashchi; Ali Esteki; Ali Motie Nasrabadi; Fereydoun Nowshiravan Rahatabad
Volume 4, Issue 3 , June 2010, , Pages 177-185
Abstract
In this study a simple inverted pendulum model with PID controller and delayed feedback is used to model standing-still postural control system for the purpose of achieving useful information about its underlying control structure. Using the Genetic algorithm and an experimental study results, the model ...
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In this study a simple inverted pendulum model with PID controller and delayed feedback is used to model standing-still postural control system for the purpose of achieving useful information about its underlying control structure. Using the Genetic algorithm and an experimental study results, the model and the controller parameters were estimated in a way that the model mimics real experimental sway patterns. The controller parameters found meaningful interpretations and it is shown that degeneration of postural control system affects the values of the parameters. Our findings indicate that although the simple models are not able to describe complexities of postural control system and interactions between its components, they can help us to improve our understanding of postural control system, its performance, its features and the way that the features change.
Cell Biomechanics / Cell Mechanics / Mechanobiology
Siavash Mazdeyasna; Amir Homayoun Jafari
Volume 5, Issue 3 , June 2011, , Pages 181-192
Abstract
In this paper, two models are introduced based on cellular automata and the game theory to study behavior, growth, development and morphology of cancerous cells by assuming nutrition supplies, extracellular matrix, and immune cells. A two-dimensional cellular automaton combine with game theory is considered ...
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In this paper, two models are introduced based on cellular automata and the game theory to study behavior, growth, development and morphology of cancerous cells by assuming nutrition supplies, extracellular matrix, and immune cells. A two-dimensional cellular automaton combine with game theory is considered as the structure of model. The cellular automata modeling framework can be an efficient approach to a number of biological problems; and game theory aims to help us to understand situations in which decision-makers interact such as competitive activity. In the first model, we consider different oxygen supplies to study the growth and invasion of cancerous cell. The results of our simulation are validated by the results of other articles. The results show that the number of cancerous cells is easily changed by changing amount of oxygen supplies, but invasive distance of tumor cells is not easily affected by this factor. Furthermore the results of this model are not linear, that could show the improvement of the model. In addition, this model has the ability of producing metastasis, as it is shown. In the second model, the interaction between immune cells and cancerous cells are considered. Two-dimensional cellular automata and game theory are used for this purpose. In this model the behavior of cellular automata is determined by the game theory. The rules of cellular automata are determined by game theory table, so each element of the system could make a decision separately.
Cell Biomechanics / Cell Mechanics / Mechanobiology
Seyed Hojat Sabzpoushan; Zahra Daneshparvar
Volume 7, Issue 3 , June 2013, , Pages 187-200
Abstract
The study of cardiac arrhythmia is a great help for prevention of the major reason of human death. To study the arrhythmias, we need cell models that not only mimic AP’s normal behavior, but also show their abnormal activity. The usual electrophysiological models contain a lot of details and hence ...
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The study of cardiac arrhythmia is a great help for prevention of the major reason of human death. To study the arrhythmias, we need cell models that not only mimic AP’s normal behavior, but also show their abnormal activity. The usual electrophysiological models contain a lot of details and hence complicate mathematics which lowers the computational efficiency. In this paper, a minimal 2-state variables model is presented that not only simulates normal characteristics of human ventricular cells like excitability, AP morphology, restitution and effects of currents block, but also replicates early after depolarization (EAD) which is an abnormal activity of cardiac cells. The presented model is a conductance based one, incorporating two currents; inward and outward that delighting all the membrane inward and outward currents respectively. The adjustment and regulation of parameters were performed using an iterative algorithm that minimizes mean squares error between model responses and real APs. The effective range of parameters for initiation of the EAD is determined by the use of dynamical system analysis theory. The simulation results are in agreement with electrophysiological realities. The computing time of the model for an one-dimensional array of 10 cells is estimated to be between 34 to 112 times faster than some well-known electrophysiological models.
Saeed Ghodsi; Hoda Mohammadzade; Hamid Aghajan
Volume 13, Issue 3 , October 2019, , Pages 189-207
Abstract
Different perceptual, cognitive and emotional situations results in a kind of information flow in the brain by means of coordinated neuronal oscillations. Analysing these oscillations, especially synchronizations of different brain regions, can illustrate the brains response in the aforementioned situations. ...
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Different perceptual, cognitive and emotional situations results in a kind of information flow in the brain by means of coordinated neuronal oscillations. Analysing these oscillations, especially synchronizations of different brain regions, can illustrate the brains response in the aforementioned situations. In the literature, connectivity between brain regions is divided into the three groups of structural, effective and functional, s.t. the first one refers to the connectivity between nearby regions, while the second and third ones focus on the synchronization of oscillations of arbitrary located regions. Although EEG is not the best choice for analyzing functional and effective connectivity between brain regions due to its relatively poor spatial resolution, extracting its statistical features may be helpful in the analysis of synchronization of brain oscillations. In this paper, a novel framework for the prediction of seizure occurrence using EEG signals is proposed which utilizes the Granger causality approach in frequency domain to measure synchronization of EEG signals in the Inter-ictal and Pre-ictal time periods. Afterwards, a Logistic Regression classifier with Lasso regularization is used to discriminate the samples extracted from these two periods. At last, if a predefined number of consecutive samples are labled as Pre-ictals, a seizure occurrence alarm is issued. Experimental simulations on the CHB-MIT dataset resulted in 95.03% sensitivity and 0.14/hour false prediction rate, for 10min prediction horizon, which demonstrates effectiveness of our proposed method compared to the state-of-the-arts.
Implant / Implant's Designing & Manufacturing
Ehsan Mohammadi Mahmoei; Reza Lashgari; Behrouz Salamat
Volume 16, Issue 3 , December 2022, , Pages 195-205
Abstract
The human body has five main senses of sight, hearing, taste, smell and touch. The defective performance of any of these senses causes us to solve this problem and use technology for this purpose. The sense of hearing is no exception and several attempts have been made to restore it, which has led to ...
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The human body has five main senses of sight, hearing, taste, smell and touch. The defective performance of any of these senses causes us to solve this problem and use technology for this purpose. The sense of hearing is no exception and several attempts have been made to restore it, which has led to the design of various implants. In this study, with the aim of investigating the function of the auditory midbrain implant (AMI) in restoring hearing ability, the cat’s auditory system has been stimulated in acoustic and electrical stimulation. Electrical stimuli are the result of AMI injecting current into the central nucleus of the inferior colliculus (ICC) and acoustic stimuli are the result of pure tone sound in the cat’s ear. After stimulation, responses were extracted from the primary auditory cortex of the cat's brain. Finally, a neural network (NN) with backpropagation-based modelling has been used. After data acquisition and processing, it was clear that AMI successfully stimulated the ICC. But it is associated with delays during stimulation. After model creation, it was found that the Levenberg-Marquardt algorithm with 10 neurons in the hidden layer had the best performance compared to the others with an error of 0.009. Also, both models show similar behaviour to frequency changes, but the electrical model at a constant frequency shows a bigger response at the output. Finally, the interval between the transmission of the neural message from the cochlear nucleus to the inferior colliculus was calculated at 9 milliseconds.
Bioinformatics / Biomedical Informatics / Medical Informatics / Health Informatics
Amin Janghorbani; Mohammad Hasan Moradi
Volume 10, Issue 3 , October 2016, , Pages 197-209
Abstract
Babies are born under 2,500 g., defined as low birth weight (LBW) babies. They are exposed to the higher risks of mortality, congenital malformations, mental retardation, and other physical and neurological impairments. 15.5 % of births around the world are LBW. Reduction of the rate of LBW births to ...
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Babies are born under 2,500 g., defined as low birth weight (LBW) babies. They are exposed to the higher risks of mortality, congenital malformations, mental retardation, and other physical and neurological impairments. 15.5 % of births around the world are LBW. Reduction of the rate of LBW births to one-third is one of the aims of United Nations Children’s Fund program. Prognosis of LBW births can play a critical role in the reduction of these cases. Also, it helps clinicians to make timely and efficient clinical decisions to save these babies' life. In this study, a hybrid framework called fuzzy evidential network with a good ability to manage different aspects of uncertainty is a selected as the LBW prognosis model. The accuracy of prognosis and the performance of the fuzzy evidential network in the management of missing values of the clinical database were investigated and compared with well-known prognosis models of LBW. The results showed that the fuzzy evidential network has higher prognosis accuracy (84.8%) than other prognosis models. On the other hand, the fusion of naïve Bayes and the fuzzy evidential network outputs resulted in higher prognosis accuracy (85.2%). In addition, the fuzzy evidential network performance in the management of uncertainty induced by imputation method, was better than other prognosis models of this study. The performance loss of this framework as the results of the missing data increment, is less than other models.
Gait Analysis
Maryam Hajizadeh; Alireza Hashemi Oskouei; Farzan Ghalichi
Volume 11, Issue 3 , September 2017, , Pages 201-210
Abstract
Anterior cruciate ligament (ACL) rupture is one of the most costly knee injuries, usually occurring to young athletes, often leading to functional instability, inability to return to previous levels of physical activity, and premature osteoarthritis (OA). The main function of ACL is controlling anterior ...
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Anterior cruciate ligament (ACL) rupture is one of the most costly knee injuries, usually occurring to young athletes, often leading to functional instability, inability to return to previous levels of physical activity, and premature osteoarthritis (OA). The main function of ACL is controlling anterior tibia translation as well as axial tibia rotation. Therefore, patients with ACL deficiency (ACLD) have to use different compensatory mechanisms and kinematic changes to maintain their stability during different activities. The study aims to measure the reliability of knee kinematics and ground reaction force during stair negotiation. Fifteen participants with unilateral ACLD ascended 4-step staircase, where 8-10 reflective markers was inserted on each segment of lower extremity. Five-camera VICON system and 10-camera VICON system were used in the first and second phase of study, respectively. Intra-class correlation coefficient (ICC) and standard error of measurement (SEM) was calculated for each parameter in the knee events during stair climbing. The results showed high consistency of kinematic parameters and GRF components was handled through reliability and repeatability calculations. ICC (2,5) showed similar values in injured and healthy contralateral leg with the range of (0.59-0.98) for all knee joint rotation and GRF components.
