233 research outputs found
Computationally Efficient QRS Detection Analysis In Electrocardiogram Based On Dual-Slope Method
A dramatic growth of interest for wearable technology has been fostered by recent technological advances in sensors, low-power integrated circuits and wireless communications. This interest originates from the need of monitoring a patient over extensive period of time. For cardiac patients, wearable heart monitoring sensors have already become a life-saving intervention ensuring continuous monitoring during daily life. Therefore, it is essential for an accurate monitoring and diagnosis of heart patients. Patients can be equipped with wireless, miniature and lightweight sensors. The sensors temporarily store physiological data and then periodically upload the data to a database server. These recorded data sets are then analyzed to predict any possibility of worsening patient\u27s situation or explored to assess the effect of clinical intervention. To obtain accurate response with less computational complexity as well as long battery life time, there is a demand of developing fast and accurate algorithm and prototypes for wearable heart monitoring sensors. A computationally efficient QRS detection algorithm is indispensable for low power operation on electrocardiogram (ECG) signal.
In need of detecting QRS complex, most of the early works were proposed based on derivatives of ECG signal. They can be easily implemented with high computational speed. But owing to the inherent variability in ECG, these methods are highly affected by large derivatives of baseline noises. Algorithms based on neural network (NN) showed relatively robust performance against noise but requires exhaustive training and estimation of model parameter. On the other hand, wavelet based methods have the choice problem of mother wavelet. Hence, none of these methods is suitable for giving a long battery performance in wearable devices with high accuracy.
Recently, Wang et al. proposed a novel dual slope QRS detection algorithm which has less computational complexity as well as high accuracy. Considering that the width of the QRS complex is relatively fixed, this algorithm is based on the fact that the largest change of slope usually happens at the peak of QRS complex. The hardware requirement is also low. However, the method has a set of time consuming slope calculations on both sides of each sample. To avoid such time consuming slope calculation, only one sample on each side can be highlighted. In addition, the multiplication of the left and right hand side slope should give us a very high value in QRS complex.
The goal of this thesis is to develop a new computationally efficient method to detect QRS complexes and compare with the other renowned QRS detection algorithms. MIT-BIH arrhythmia database based on patients of different heart diseases and database containing ECG from healthy subjects are used. To analyze the performance, false negative (FN) and false positive (FP) are evaluated. A false negative (FN) occurs when algorithm fails to detect an actual QRS complex quoted in the corresponding annotation file of the database record and a false positive (FP) means a false beat detection. Error rate (ER) , Sensitivity (Se) and Specificity (Sp) are calculated using FP and FN
Introducing Australia’s first hybrid testing facility for performance-based assessment of structures
Hybrid simulation is a cost-effective cyber-physical testing technique, in which computational models and physical components are integrated at run-time. This method can be viewed as conventional finite element analysis, where physical models of some portions of the structure are embedded in the numerical model. In such a way, the errors related to the simplification of the theoretical modeling of complex nonlinear structures or subassemblies can be effectively mitigated as they are tested physically in the lab. This paper introduces Australia’s first hybrid testing facility, referred to as the Multi-Axis Substructure Testing (MAST) system, which is capable of simulating the complex three-dimensional time-varying boundary effects on large-scale structural components. The MAST system is unique in Australasia and is capable to serve the research community and practice, nationally and internationally. An application of the MAST system to investigate the performance of a CFRP-repaired limited-ductile RC column under sequential ground motions from linear-elastic response range through collapse is also presented
Enchondroma of the scaphoid: a case report
Enchondroma represents a common bone tumor of the hand. The scaphoid is a rare location. We report the case of a scaphoid enchondroma presenting as chronic wrist pain following a relatively minor trauma. The diagnosis was suggested by radiological study and then confirmed by histological study after biopsy. Enucleation and vascularized bone graft with osteosynthesis provided good results. The clinical, radiological and therapeutic aspects of this rare condition are discussed
Theoretical investigations of β-tricalcium
Beta-tri-calcium phosphate (β-TCP) materials have gained a great deal of research considerations in biomaterial area due to their excellent biocompatibility and identical chemical compositions to the natural teeth and bones. Therefore, the β-TCP compound can be used as coatings, cement and composites as well as biocompatible ceramics for medical and dental applications. Electronic and optical properties for β-TCP compound have been investigated using density functional theory (DFT). For the calculations, we used full potential linear augmented plane wave method (FPLAPW), within three types of approximations along with local density approximations (LDA), generalized gradient approximations (GGA) and Modified Becke-Johnson (mBJ) to get the effect of the exchange and correlation in our calculations to get an accurate results. The computed band gap values for (β-TCP) compound using LDA, GGA, and mBJ-GGA approximations are 5.5 eV, 5.9 eV and 6.8 eV respectively. This is also predicted that the chemical bonding in this compound is a kind of combination of covalent and ionic character that is in a line with the experimental findings. The optical parameter, static dielectric constant ε1(0) reaches the values of 3.23681 (eV) at 0 GPa for the β-TCP compound. The obtained results are of vital nature for rising the quality of the electronic and optical properties of this material, and provide more evidence to fabricate novel Beta-Tri-calcium phosphate biomaterials for medical and dental applications
Density functional theory study of the electronic and optical properties of pure and magnesium doped Β-tricalcium phosphate compound
β-Tri-calcium phosphate material (β-TCP), have attract a wide interest in the material science and medical science applications, due to its excellent biocompatibility and its identical chemical compositions to the natural teeth and bones. For that reason, (β-TCP) compound is widely used as biocompatible ceramics in medical and dental science applications. However, research shows that, pure β-TCP material has lower ability to stimulate the growth of natural bone and teeth as needed. Therefore, in order to address this deficiency magnesium impurity is used to replace calcium in the matrix of pure β-TCP to enhance its electronic and optical properties which are not present in the pure one. Thereby, its biological performance becomes improved. By changing the chemical composition of β-TCP to be similar to the mineral compositions of the natural teeth and bones. This will give more insight in fabrication of biomaterial devices for replacing, repairing and rebuilding the broken or damaged human teeth and bones. Here, we present the study of compound β-TCP using density functional theory (DFT). For the calculations, we used full potential linear augmented plane wave method (FPL-APW), along with generalized gradient approximations (GGA) potential. The band gap values of 5.2 eV and 3.4 eV are obtained for the pure and Mg-doped β-TCP, respectively. These results are in good agreement with the experimental values. Our results show peaks which correspond to the refractive index, complex dielectric function, optical conductivity, optical reflectivity, extinction coefficient, absorption efficient, and electron energy loss. These peaks are shifted towards the higher energy values for the pure and Mg-doped β-TCP material. The obtained results have more significance for increasing the quality of electronic and optical properties of this material and offer more evidences to synthesize enhanced β-TCP material for dental and medical applications
Uncertainty and crude oil returns
We use a copula approach to investigate the effect of uncertainty on crude-oil returns. Using copulas to construct multivariate distributions of time-series data permit the calculation of the dependence structure between the series independently of the marginal distributions. Further, we implement the copula estimation using a rolling window method to allow for a time-varying effect of equity and economic policy uncertainty on oil returns. The results show that higher uncertainty, as measured by equity and economic policy uncertainty indices, significantly increase crude-oil returns only during certain periods of time. That is, we find a positive dependence prior to the financial crisis and Great Recession. Interestingly, estimation of the copula over the entire sample period leads to a negative dependence between the equity and economic policy indices and the crude-oil return.http://www.elsevier.com/locate/eneco2017-03-31hb2016Economic
How Do Parental Factors Increase the Probability for Autism and Attention Deficit Hyperactivity Disorder?
Two prevalent neurodevelopment disorders in children are attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). The fifth version of the Diagnostic and Statistical Manual of Mental Disorders describes autism as a condition marked by limitations in social communication as well as restricted, repetitive behavior patterns. While impulsivity, hyperactivity, and lack of concentration are signs of attention deficit hyperactivity disorder. Boys experience it more frequently than girls do. This study sought for possible factors that put children at risk for autism and attention deficit hyperactivity disorder, and it investigated the association between neurodevelopment disorders in children and parental risk factor in Iraqi population. This was a cross sectional, comparative study applied in The National Center for Autism/Medical City Complex from January to April 2022.In which120 child withneuro development disorders and 120 controls participated. The data collected from the questionnaires was analyzed using SPSS 25. Independent T-test and Chi-Square test were carried out for the bivariate analysis of the data. Among the tested variables four parent-related factors were significantly (P-value < 0.05) associated with neurodevelopment disorders in children: Family history of psychiatric illness, smoking of any parent, pregnancy and labor complications, used progesterone during pregnancy. In addition to these significant parent-related risk factors, paternal age at conception time were significantly (P-value < 0.05) associated with neurodevelopment disorders of children. Based on this case control study, mothers with pregnancy & labor complications, paternal age at conception, smoking of any parent,mothers used progesterone during pregnancy and family history of psychiatric illness, had higher risk of neurodevelopment disorders
Severity of asthma: the role of CD25+,CD30+, NF-κB, and apoptotic markers
Objectives: We studied the role of the regulatory T cells CD4+CD25+ (Treg) and activated CD4+CD30+ cells in the pathogenesis of asthma and their association with apoptosis and NF-κB in patients with mild intermittent asthma (MA), severe persistent asthma (SA), and healthy volunteers (HV).
Methods: Peripheral blood lymphocytes (PBL) were extracted from asthmatic patients during exacerbations, and CD4+ cells were separated using Dynal beads. Immunostaining of whole PBL for NF-κB, Bax, and Bcl-2, and immunostaining of CD4+ cells for CD25+ and CD30+ cells were performed using immunocytochemistry.
Results: Treg cells were expressed at higher levels in MA than in HV and SA (P.05). Levels of NF-κB, Bcl-2, and Bcl-2/Bax increased, whereas those of Bax decreased, progressively, from MA to SA (P<.05). NF-κB levels correlated directly with the Bcl-2/Bax ratio and with CD4+CD30+ cells in SA and MA, whereas CD4+CD30+ cells correlated inversely with the Bcl-2/Bax ratio.
Conclusions: Unregulated Treg cells probably return inflammatory responses to normal values during exacerbations in MA; however, expression of Treg cells was extensively diminished in SA, leading to probable loss of suppressive control over underlying immune reactions. CD4+CD30+ cells were associated with the pathogenesis of asthma but not with severity. NF-κB seems to be the central inflammatory factor in SA, with a remarkable loss of PBL apoptosis, diminished Treg levels, and high CD30+ cell levels that probably induce NF-κB, which in turn blocks the proapoptotic potential of CD30 induction itself
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