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Analysis of heart rate variability (HRV) is one of the most important noninvasive methods of measuring autonomic nervous system (ANS) activities. Hence, simulation of a realistic sequence of HRV signal can have a significant impact on diagnosis of different diseases related to ANS. In this paper, the focus is on generating realistic R-R interval signals using frequency domain analysis. An algorithm...
Several biological effects have been reported for mechanical forces on individual cells including: signal transduction, gene expression, growth, and differentiation. In this paper, a novel model for studying the cell behavior under the effect of stresses is developed. A well-defined fluid flow passing over a single cell fixed inside a microchannel is considered in this model. By multi-scale modeling...
Hydrogels based on natural polysaccharides are found to be so appealing for wound healing applications. The present study deals with the synthesis and characterization of PVA/acacia gum hybrid hydrogels where Arabic gum was evaluated as network properties improvement factor in hybrid hydrogel with the capability of antimicrobial agent (erythromycin) delivery in wound site. The comparison of drug release...
This paper presents an approach to represent and match images for retrieval in medical archives. A multidimensional low-level feature space including shape and texture is used to represent the image input. The large intensity variation and low contrast are main characteristics of the medical images. This presents a challenge to matching among the images, and is handled via an illumination-invariant...
The recruitment pattern of trunk muscles is determined using a three-dimensional model of the spine with two joints and six symmetric pairs of muscles in which both equilibrium and stability requirements are satisfied. Model predictions are verified using Anybody Modeling System (AMS) and Abaqus. The model is used to test the hypothesis that antagonistic muscle activities are necessary for the spinal...
Wireless capsule endoscopy (WCE) is a relatively new technology that captures images of the entire gastrointestinal tract non-invasively and painlessly. A large number of frames are captured during an examination. The main difficulty for physicians is to review the frames visually. In recent years, some methods have been devised to help physicians. Here, a novel method is devised to distinguish among...
Nowadays one of the most important causes of mortality is cardiovascular disease, especially coronary artery stenosis. Therefore, it is important to find an accurate and fast way to diagnose them. Computed tomography angiography is a non-invasive imaging method for the heart and its vessel, which can be used instead of angiography in many cases. Indeed, the main focus is on developing an automatic...
Vertebroplasty is an invasive treatment which not only reduces pain in patient but also stabilize fractured vertebra. Usage of Vertebroplasty has increasing rate among surgeons in recent decay. In this study we investigate the effects of cement properties and distribution on mechanical response of lumbar spine. A three-dimensional finite element model created from CT images of L1–L3. According to...
Heart is a complex system and we can find its function in electrocardiogram (ECG) signal. The records show high mortality rate of heart diseases. So it is essential to detect and recognize ECG arrhythmias. The problem with ECG analysis is the vast variations among morphologies of ECG signals. Premature Ventricular Contractions (PVC) is a common type of arrhythmia which may lead to critical situations...
Tracking the rapid motions and vibrations of the carotid artery wall is an important issue in the noninvasive carotid ultasonography. In order to capture the fast moving structures and vibrations, high frame rate B-mode sequences, without decreasing lateral resolution, are needed. In the present paper, manifold learning is used to find the relation between the frames during a cardiac cycle as well...
The central nervous system (CNS) uses a redundant set of joints and muscles to ensure both flexible and stable movements. How the CNS faces the complexity of control problem is not still clear. Modular control is one of the most attractive hypotheses in motor control. In this hypothesis, some motor primitives (e.g. muscle synergies) are considered as the building blocks that can be combined to present...
Coronary Artery Diseases are one of the main reasons of mortality. When these arteries occlude, usually a Coronary Artery Bypass Graft (CABG) surgery is performed. Sine human Saphenous Veins (SV) are used for CABG, they are of interest for researchers. In this study human SV samples undergo inflation test, using an inflation test device. Displacements of the samples for different pressures are analyzed,...
This paper presents an algorithm for predicting termination of paroxysmal atrial fibrillation (PAF) attacks by using higher order statistical moments of RR-intervals signal calculated in the empirical mode decomposition (EMD) domain. In the proposed method, RR-intervals signal is decomposed into a set of intrinsic mode functions (IMF) and higher order moments including variance, skewness, and kurtosis,...
Advanced medical imaging techniques require high performance segmentation algorithms. Extracting the structures of interest accurately is one of the main challenges in medical imaging segmentation. In this paper a methodological approach based on active contour is proposed for fully automated segmentation of radius bone. As soft tissues like tendons, muscles and fat around the bone have close intensities...
To relate electromyographic signals (EMG) to net joint torque, different approaches have been taken into account. In this regard, some researchers chose to use Principal Component Analysis (PCA). A Study in 2001 reported a linear relationship between the PCA-processed EMG data and the joint torque while investigating isometric movements. In this project we questioned the possibility to use this method...
An abnormal narrowing of a blood vessel (stenosis) is investigated in this study. The present work provides a simulation of blood in a vessel with 50% stenosis. In addition, the effects of tissue surrounding the blood vessel on displacements and stresses in stenotic vessel wall are considered. The analysis consists of two distinct but coupled procedures: first, a fluid-dynamics analysis including...
In this work we propose a model to describe impairment of Long-Term Potentiation (LTP) due to Amyloid Beta (Aβ) accumulation during Alzheimer's Disease (AD) in hippocampus. The model embeds astrocyte-neuron interactions and Spike Timing-Dependent Plasticity (STDP) in CA3-CA1 synapses. In our proposed model, considering physiological facts, each astrocyte has a bidirectional signaling with four neurons,...
Electroencephalogram (EEG)-based emotion recognition has been a rapidly growing field. However, accurate and sufficient performance rates are yet to be obtained. This paper presents the classification of EEG correlates on emotion using the relatively new non-linear feature extraction method, namely, Recurrence Plot analysis to extract thirteen non-linear features. This method is compared with feature...
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