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Search Results: 1 - 10 of 374 matches for " bolfazl Taheri "
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Correlation Between Upper Airways Obstructive Indexes in Adenotonsilar Hypertrophy with Mean Pulmonary Arterial Pressure
Ehsan Khadivi,Mohsen Horri,Monavar Afzal Aghaee,bolfazl Taheri
Iranian Journal of Otorhinolaryngology , 2010,
Abstract: Introduction: Hypertrophied tonsils and adenoids may cause upper airway obstruction and cardio-pulmonary complications due to pulmonary arterial hypertension. The aim of this study was to determine the correlation between mean pulmonary arterial pressure (mPAP) and selected adenotonsilar hypertrophy indexes. Materials and Methods: Thirty two patients with upper-airway obstruction resulting from hypertrophied tonsils and adenoids were included in our study. Mean pulmonary arterial pressure was measured by a non-invasive method using color doppler echocardiography. Upper airway obstruction was evaluated by clinical OSA (obstructive sleep apnea) scoring and also adenoidal-nasopharyngeal (A/N) ratio in the lateral neck radiography. Results: Fifty percent of the patients with a normal OSA score, 20% of those with a suspected OSA score and also 50% of cases with OSA had pulmonary hypertension (mPAP>20mmHg) which was not statistically significant (P=0.198). Mean Adenoidal-nasopharyngeal ratio in patients with a normal mPAP (mPAP≤20mmHg) was 0.61±0.048 and it was 0.75±0.09 in those with pulmonary hypertension; the difference was statistically significant (P=0.016). Conclusion: It seems that A/N ratio could be used as a predicting factor for increased mPAP in children with upper airway obstruction and a pediatric cardiologist consultation may be necessary before some surgical interventions.
Short course of cyclophosphamide therapy may reduce recurrence in patients with tubulointerstitial nephritis and uveitis syndrome
Taheri Shahram,Taheri Diana
Saudi Journal of Kidney Diseases and Transplantation , 2009,
Abstract: We report a 43-year-old woman with tubulointerstitial nephritis and uveitis syn-drome (TINU syndrome) presented with a 5-day complaint of chills and fever, anorexia, nausea, and vomiting. She had elevated BUN and creatinine and urinalysis revealed decreased concen-tration, proteinuria, hematuria, and pyuria. A kidney biopsy showed non-caseating granulomatous tubulointerstitial nephritis. She suffered from anterior uveitis one month before, which was managed with local ophthalmic steroids. She received two months of oral high dose prednisolone, which was tapered over the next two months, and two months of 2 mg/kg cyclophosphamide. Her renal function recovered during the first two months. Her kidney and ocular symptoms did not recur during one year of follow-up. We suggest short course of cyclophosphamide and prednisolone for treatment of TINU syndrome to decrease the recurrence of kidney and ocular involvement.
Simulation and Design of a Submicron Ultrafast Plasmonic Switch Based on Nonlinear Doped Silicon MIM Waveguide  [PDF]
Ahmad Naseri Taheri, Hassan Kaatuzian
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.17006
Abstract:

We propose and analyze a submicron stub-assisted ultrafast all-optical plasmonic switch based on nonlinear MIM waveguide. It is constructed by two silicon stub filters sandwiched by silver cladding. The signal wavelength is assumed to be 1550 nm. The simulation results show a ?14.66 dB extinction ratio. Downscaling the silicon waveguide in MIM structure leads to enhancement of the effective Kerr nonlinearity due to tight mode confinement. Also, using O+ ions implanted into silicon, the switching time less than 10 ps and a delay time less than 8 fs are achieved. The overall length of the switch is 550 nm.

q-Laplace Transform  [PDF]
Shahnaz Taheri, Maryam Simkhah Asil
Advances in Pure Mathematics (APM) , 2016, DOI: 10.4236/apm.2016.61003
Abstract: The Fourier transformations are used mainly with respect to the space variables. In certain circumstances, however, for reasons of expedience or necessity, it is desirable to eliminate time as a variable in the problem. This is achieved by means of the Laplace transformation. We specify the particular concepts of the q-Laplace transform. The convolution for these transforms is considered in some detail.
Prevalence of macular amyloidosis in north Iran
Taheri Ramin
Indian Journal of Dermatology , 2007,
Abstract: Macular amyloidosis is a relatively common cutaneous disease in Asia and the Middle East. It is characterized by a reticulated or rippled pattern of pigmentation mostly in the upper back. This study was performed not only to determine the disease, sex and age distribution but also to evaluate its risk factors and the frequency among the patients in the dermatology clinic. In this study, 100 macular amyloidosis patients were evaluated in a period of 4 years. The sex ratio (female:male) of the patients was 9:1, and the mean age of the female patients was higher than that of the males. We found no evidence of any other associated risk factors.
The Mental and Psychological Deleterious Effect of Noise on the Operators of Telecommunication Company
Mohammad Taheri
Audiology , 1999,
Abstract: Nowadays, unwanted noise is present everywhere in the workplace and in the living environment and disturbs human peace and calm. In spite of the importance of the indirect impact of noise on human life, little is performed about this issue in our country. Therefore, the present study have been focused on the measurement of noise pollution that impose operators of the telecommunication company in addition to the evaluation of the psychological and mental effect of sound on the telecommunication operators.
E2E KEEP: End to End Key Exchange and Encryption Protocol for Accelerated Satellite Networks  [PDF]
Hossein Fereidooni, Hassan Taheri, Mehran Mahramian
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.54030
Abstract: Accelerating methods are used to enhance TCP performance over satellite links by employing Performance Enhancement Proxies (PEPs). However, providing a secure connection through the PEPs seems to be impossible. In this paper an appropriate method is proposed in order to provide an accelerated secure E2E connection. We show an efficient secure three-party protocol, based on public key infrastructure (PKI), which provides security against spiteful adversaries. Our construction is based on applying asymmetric cryptography techniques to the original IKE protocol. Security protocols use cryptography to set up private communication channels on an insecure network. Many protocols contain flaws, and because security goals are seldom specified in detail, we cannot be certain what constitute a flaw. Proofing security properties is essential for the development of secure protocol. We give a logic analysis of the proposed protocol with the BAN-logic and discuss the security of the protocol. The result indicates that the protocol is correct and satisfies the security requirements of Internet key exchange. Based on the results of this preliminary analysis, we have implemented a prototype of our security protocol and evaluated its performance and checked safety properties of security protocol, and the results show that the protocol is robust and safe against major security threats.
Mechanical Validation of Perfect Tibia 3D Model Using Computed Tomography Scan  [PDF]
Ehsan Taheri, Behrooz Sepehri, Reza Ganji
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.412111
Abstract: In this paper, the Von Mises stresses and stiffnesses measured by experiments on a human cadaveric tibia and composite ones compared to those predicted by a FE model based on the same bone. Modeling of exact geometrical tibia including cortical and spongy bone using human bone CT scan images and mechanical validating of obtained model, is the aim of this study .The model produced by the current study supplies a tool for simulating mechanical test conditions on human tibia.
Speech Analysis for Diagnosis of Parkinson’s Disease Using Genetic Algorithm and Support Vector Machine  [PDF]
Mohammad Shahbakhi, Danial Taheri Far, Ehsan Tahami
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.74019
Abstract: Parkinson’s disease (PD) is the most common disease of motor system degeneration that occurs when the dopamine-producing cells are damaged in substantia nigra. To detect PD, various signals have been investigated, including EEG, gait and speech. Since approximately 90 percent of the people with PD suffer from speech disorders, speech analysis is considered as the most common technique for this aim. This paper proposes a new algorithm for diagnosing of Parkinson’s disease based on voice analysis. In the first step, genetic algorithm (GA) is undertaken for selecting optimized features from all extracted features. Afterwards a network based on support vector machine (SVM) is used for classification between healthy and people with Parkinson. The dataset of this research is composed of a range of biomedical voice signals from 31 people, 23 with Parkinson’s disease and 8 healthy people. The subjects were asked to pronounce letter “A” for 3 seconds. 22 linear and non-linear features were extracted from the signals that 14 features were based on F0 (fundamental frequency or pitch), jitter, shimmer and noise to harmonics ratio, which are main factors in voice signal. Because changing in these factors is noticeable for the people with PD, optimized features were selected among them. Of the various numbers of optimized features, the data classification was investigated. Results show that the classification accuracy percent of 94.50 per 4 optimized features, the accuracy percent of 93.66 per 7 optimized features and the accuracy percent of 94.22 per 9 optimized features, could be achieved. It can be observed that the best classification accuracy may be achieved using Fhi (Hz), Fho (Hz), jitter (RAP) and shimmer (APQ5).
Damping Controller Based Quantum Particle Swarm Optimization for VSC HVDC to Improve Power System Stability  [PDF]
Naser Taheri, Ahmad Hashemi, Kowsar Kiani
Energy and Power Engineering (EPE) , 2014, DOI: 10.4236/epe.2014.612035
Abstract: The use of the supplementary controllers of a High Voltage Direct Current (HVDC) based on Voltage Source Converter (VSC) to damp low Frequency oscillations in a weakly connected system is surveyed. Also, singular value decomposition (SVD)-based approach is used to analyze and assess the controllability of the poorly damped electromechanical modes by VSC-HVDC different control channels. The problem of supplementary damping controller based VSC-HVDC system is formulated as an optimization problem according to the time domain-based objective function which is solved using quantum-behaved particle swarm optimization (QPSO). Individual designs of the HVDC controllers using QPSO method are evaluated. The effectiveness of the proposed controllers on damping low frequency oscillations is checked through eigenvalue analysis and non-linear time simulation under various disturbance conditions over a wide range of loading.
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