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Medical Signals and Sensors - Volume:7 Issue: 4, Oct-Dec 2017

Journal of Medical Signals and Sensors
Volume:7 Issue: 4, Oct-Dec 2017

  • تاریخ انتشار: 1396/08/17
  • تعداد عناوین: 9
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  • Mina Golzar, Faranak Fotouhi*, Hossein Rabbani, Fahimeh Sadat Zakeri Page 193
    Background
    The increasing trend of heart disease has turned the attention of researchers toward the use of portable connected technologies. The necessity of continuous special care for cardiovascular patientsis an inevitable fact.
    Methods
    In this research, a new wireless electrocardiographic (ECG) signalmonitoring system based on smartphone is presented. This system has two main sections. The first section consists of a sensor which receives ECG signals via an amplifier, then filters and digitizes the signal, and prepares it to be transmitted. The signals are stored, processed, and then displayed in a mobile application. The application alarms in dangerous situations and sends the location of the cardiac patient to family or health-care staff.
    Results
    The results obtained from the analysis of the electrocardiogram signals on 20 different people have been compared with the traditional ECG in hospital by a cardiologist. The signal is instantly transmitted by 200 sample per second to mobile phone. The raw data are processed, the anomaly is detected, and the signal is drawn on the interface in about 70 s. Therefore, the delay is not noticeable by the patient. With respect to rate of data transmission to hospital, different internet connections such as 2G, 3G, 4G, WiFi, WiMax, or Long-Term Evolution (LTE) could be used. Data transmission ranges from 9.6 kbps to 20 Mbps. Therefore, the physician could receive data with no delay.
    Conclusions
    A performance accuracy of 91.62% is obtained from the wireless ECG system. It conforms to the hospital’s diagnostic standard system while providing a portable monitoring anywhere at anytime.
    Keywords: Arrhythmia detection, cardiac, electrocardiogram, mobile health care, telemedicine
  • Zahra Nadealian*, Behzad Nazari, Saeid Sadri, Mohammad Momeni Page 203
    Background
    Pulmonary nodules are symptoms of lung cancer. The shape and size of these nodules are used to diagnose lung cancer in computed tomography (CT) images. In the early stages, nodules are very small, and radiologist has to refer to many CT images to diagnose the disease, causing operator mistakes. Image processing algorithms are used as an aid to detect and localize nodules.
    Methods
    In this paper, a novel lung nodules detection scheme is proposed.First, in the preprocessing stage, our algorithm segments two lung lobes to increase processing speed and accuracy. Second, template‑matching is applied to detect the suspicious nodule candidates, including both nodules and some blood vessels. Third, the suspicious nodule candidates are segmented by localized active contours. Finally, the false‑positive errors produced by vessels are reduced using some two‑/three‑dimensional geometrical features in three steps. In these steps, the size, long and short diameters and sphericity are used to decrease the false‑positive rate.
    Results
    In the first step, some vessels that are parallel to CT cross‑plane are identified. In the second step, oblique vessels are detected using shift of center of gravity in two successive slices. In step three, vessels vertical to CT cross‑plane are identified. Using these steps, vessels are separated from nodules. Early Lung Cancer Action Project is used as a popular dataset in this work.
    Conclusions
    Our algorithm achieved a sensitivity of 90.1% and a specificity of 92.8%, quite acceptable in comparison to other related works.
    Keywords: Computer‑aided detection, computed tomography images, feature extraction, localized active contours, pulmonary nodules, template matching
  • Mohammad Bagher Tavakoli, Habiballah Moradi*, Hossein Khanahmad, Mohsen Hosseini Page 213
    Background
    The aim of this study was to develop a nucleotide geometrical model of the circular mitochondrial DNA (mt‑DNA) structure using Geant4‑DNA toolkit to predict the radiation‑induceddamages such as single‑strand breaks (SSB), double‑strand breaks (DSB), and some other physical parameters.
    Methods
    Our model covers the organization of a circular human mt genetic system. The current model includes all 16,659 base pairs of human mt‑DNA. This new mt‑DNA model has been preliminarily tested in this work by determining SSB and DSB DNA damage yields and site‑hit probabilities due to the impact of proton particles. The accuracy of the geometry was determined by three‑dimensional visualization in various ring element numbers. The hit locations were determined with respect to a reference coordinate system, and the corresponding base pairs were stored in the ROOT output file.
    Results
    The coordinate determination according to the algorithm was consistent with the expected results. The output results contain the information about the energy transfers in the backbone region of the DNA double helix. The output file was analyzed by root analyzing tools. Estimation of SSBs and DSBs yielded similar results with the increment of incident particle linear energy transfer. In addition, these values seem to be consistent with the corresponding experimental determinations.
    Conclusions
    This model can be used in numerical simulations of mt‑DNA radiation interactions to perform realistic evaluations of DNA‑free radical reactions. This work will be extended to supercoiled conformation in the near future.
    Keywords: Geant4, geometrical model, mitochondrial‑DNA, Monte Carlo, radiation
  • Omid Sarrafzadeh*, Alireza M. Dehnavi, Hossein Y. Banaem, Ardeshir Talebi, Arshin Gharibi Page 220
    Background
    Differential counting of white blood cells (WBCs or leukocytes) is a common task to diagnose many diseases such as leukemia, and infections. An accurate process for recognizing leukocytes is to evaluate a blood smear under a microscope by an expert. Since, this procedure is manual, time-consuming and tedious, making the procedure automatic would overcome these problems. In an automated CAD (Computer-Aided-Design) system for this purpose, a crucial module is leukocytes recognition. In this paper, we are looking for the best features in order to recognize five types of leukocytes (Monocyte, Lymphocyte, Neutrophil, Eosinophil and Basophil) from microscopic images of blood smear in an automated cell counting system.
    Methods
    In this work, we focus on the texture features and seven categories: GLCM features, Haralick features, Spectral texture features, Waveletbased features, Gabor-based features, CoALBP and RICLBP are analyzed to find the best features for leukocytes detection. The best features of each category are selected using stepwise regression and finally three well-known classifiers called K-NN, LDA and NB are utilized for classification.
    Results
    The proposed system is tested on a self-provided dataset composed of 200 cell images. In our experiments, to evaluate the process, the accuracy of each leukocyte type and the mean accuracy are computed. RICLBP features achieved the best mean accuracy (85.53%) for LDA classifier.
    Conclusions
    In our experiments, although the maximum mean accuracy (85.53%) went with RICLBP features, but the accuracies of all five leukocyte types weren’t maximized for RICLBP features. This result directs us to design and develop a system based on multiple features and multiple classifiers to maximize the accuracies even for each individual cell type in our future work.
    Keywords: Automatic leukocytes recognition, best texture features, blood smear, computer-aided design (CAD) system, microscopic images
  • Mohammad Ali Salami, Faranak Kaveian, Mohammad Rafienia*, Saeed Saber- Samandari, Amirsalar Khandan, Mitra Naeimi Page 228
    Background
    Biopolymer scaffolds have received great interest in academic and industrial environment because of their supreme characteristics like biological, mechanical, chemical, and cost saving in the biomedical science. There are various attempts for incorporation of biopolymers with cheap natural micro- or nanoparticles like lignin (Lig), alginate, and gums to prepare new materials with enhanced properties.
    Methods
    In this work, the electrospinning (ELS) technique as a promising cost-effective method for producing polymeric scaffold fibers was used, which mimics extracellular matrix structure for soft tissue engineering applications. Nanocomposites of Lig and polycaprolactone (PCL) scaffold produced with ELS technique. Nanocomposite containings (0, 5, 10, and 15 wt.%) of Lig were prepared with addition of Lig powder into the PCL solution while stirring at the room temperature. The bioactivity, swelling properties, morphological and mechanical tests were conducted for all the samples to investigate the nanocomposite scaffold features.
    Results
    The results showed that scaffold with 10 wt. % Lig have appropriate porosity, biodegradation, minimum fiber diameter, optimum pore size as well as enhanced tensile strength, and young modulus compared with pure PCL. Degradation test performed through immersion of samples in the phosphate-buffer saline showed that degradation of PCL nanocomposites could accelerate up to 10% due to the addition of Lig.
    Conclusions
    Electrospun PCL-Lig scaffold enhanced the biological response of the cells with the mechanical signals. The prepared nanocomposite scaffold can choose for potential candidate in the biomedical science.
    Keywords: Electrospinning, lignin, nanocomposite, polycaprolactone, scaffold, tissue engineering
  • Amirsalar Khandan, Mohammad Rafienia Page 228
    Background
    Biopolymer scaffolds have received great interest in academic and industrial environment because of their supreme characteristics like biological, mechanical, chemical, and cost saving in the biomedical science. There are various attempts for incorporation of biopolymers with cheap natural micro- or nanoparticles like lignin (Lig), alginate, and gums to prepare new materials with enhanced properties.
    Materials And Methods
    In this work, the electrospinning (ELS) technique as a promising cost-effective method for producing polymeric scaffold fibers was used, which mimics extracellular matrix structure for soft tissue engineering applications. Nanocomposites of Lig and polycaprolactone (PCL) scaffold produced with ELS technique. Nanocomposite containings (0, 5, 10, and 15 wt.%) of Lig were prepared with addition of Lig powder into the PCL solution while stirring at the room temperature. The bioactivity, swelling properties, morphological and mechanical tests were conducted for all the samples to investigate the nanocomposite scaffold features.
    Results
    The results showed that scaffold with 10 wt.% Lig have appropriate porosity, biodegradation, minimum fiber diameter, optimum pore size as well as enhanced tensile strength, and young modulus compared with pure PCL. Degradation test performed through immersion of samples in the phosphate-buffer saline showed that degradation of PCL nanocomposites could accelerate up to 10% due to the addition of Lig.
    Conclusions
    Electrospun PCLLig scaffold enhanced the biological response of the cells with the mechanical signals. The prepared nanocomposite scaffold can choose for potential candidate in the biomedical science
    Keywords: Electrospinning, lignin, nanocomposite, polycaprolactone, scaffold, tissue engineering
  • Zahra Khodadadi, Hamid R. Kobravi*, Milad F. Majd Page 239
    Stimulation of spinal sensorimotor circuits can improve motor control in animal models and humans with spinal cord injury (SCI). More recent evidence suggests that the stimulation increases the level of excitability in the spinal circuits, activates central pattern generators, and it is also able to recruit distinctive afferent pathways connected to specific sensorimotor circuits. In addition, the stimulation generates well‑defined responses in leg muscles after each pulse. The problem is that in most of the neuromodulation devices, electrical stimulation parameters are regulated manually and stay constant during movement. Such a technique is likely suboptimal to intercede maximum therapeutic effects in patients. Therefore, in this article, a fuzzy controller has been designed to control limb kinematics during locomotion using the afferent control in a neuromechanical model without supraspinal drive simulating post‑SCI situation. The proposed controller automatically tunes the weights of group Ia afferent inputs of the spinal cord to reset the phase appropriately during the reaction to an external perturbation. The kinematic motion data and weights of group Ia afferent inputs were the input and output of the controller, respectively. Simulation results showed the acceptable performance of the controller to establish adaptive locomotion against the perturbing forces based on the phase resetting of the walking rhythm.
    Keywords: Afferent control, central pattern generator, fuzzy controller, movement stabilizing, spinal cord injury
  • Ali Jomehzadeh, Daryoush Shahbazi- Gahrouei*, Vahid Jahanbakhsh Page 247
    The head scatter factor (Sc) is important to measurements radiation beam and beam modeling of treatment planning systems used for advanced radiation therapy techniques. This study aimed to investigate the design of a miniphantom to measurement variations in collimator Sc in the presence of shielding blocks for shaping the beam using different field sizes. Copper, Brass, and Perspex buildup caps were designed and fabricated locally as material with three different thicknesses for buildup caps (miniphantoms). Measurements were performed on an Elekta Compact medical linear accelerator (6 MV) in Shafa Kerman Hospital, Iran. The Farmer-type ion chamber FG65-P (Scanditronix, Wellhofer) was used for all measurements. To measure the Sc, miniphantom was positioned in a stand vertical to the beam central axis. The data indicate that the Sc measurements using different buildup cap materials and thicknesses in 5 × 10, 7.5 × 7.5, and two 10 × 10 cm Cerrobend shield blocks ranged 0.98 to 1.00, 1.04 to 1.05, and 1.04 to 1.06, respectively. Also, it was observed that by increasing the block shield area from 50 cm2 to both 56.25 and 100 cm2, the Sc increased in all situations. Results showed that using Brass compared to Perspex and Copper has less uncertainty due to its simple preparation and cutting which is useful to measurement of variations in collimator Sc and shaping the photon beam.
    Keywords: cerrobend block, linear accelerator, miniphantom, radiation therapy, scatter collimator factor
  • Farhad Forouharmajd, Mehrdad Yadegari, Masoumeh Ahmadvand, Farshad Forouharmajd, Siamak Pourabdian* Page 252
    Effects of vibration appear as mechanical and psychological disorders, including stress reactions, cognitive and movement disorders, problem in concentration and paying attention to the assigned duties. The common signs and symptoms of hand‑arm vibration (HAV) in the fingers and hands may appear as pins and needles feeling, tingling, numbness, and also the loss of finger sensation and dexterity. Laboratory Virtual Instrument Engineering Workbench programming software designed for occupational vibrations measurement was used to calculate HAV acceleration. Hole steadiness test is designed to measure involuntary movement of people. V‑Pieron test is designed for one of the other aspects of the psycho motor phenomena of steadiness by moving the stylus across a V‑form ruler. The two points test was an experiment of touch acuity, which used a caliper by placing the two styli very close on the pad of finger knuckles. The temperature of finger skin is also measured simultaneous to the above tests. Wilcoxon test indicated that a significant decrement in hand steadiness occurred after gripping a vibrating handle for 2 min (P ≤ 0.003). Wilcoxon test also represented a significant change in errors after gripping a grinder vibratory handle (P ≤ 0.003). The differences at all of the knuckles were significant with a confidence interval percentage of 99%. There was a significant reduction in finger skin temperature before and after exposure to vibration (mean = 0.45°C, based on paired sample test). The obtained results considerably demonstrated the relation between hand performance and vibrations due to gripping a grinder. It can be concluded that an injury or accident may happen after exposure to vibrations for the fine duties, in fast actions.
    Keywords: Hand performance, hand‑arm vibration, tactile acuity, temperature