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匹配条件: “Tahereh Jazayeri S” ,找到相关结果约324702条。
Comparison Study of Memory Status in War-PTSD Veterans With Depression and Non- Veterans Depressed Patient
Radfar Sh,Tahereh Jazayeri S,Haghani H,Habibi M
Tehran University Medical Journal , 2012,
Abstract: Background: Cognitive problems in patients with post-traumatic stress disorder (PTSD) include poor concentration and impaired memory. Prevalence of PTSD in all aspects of life is 8% in USA. Regarding the importance of memory in functional levels, this study was performed to review memory status in these patients. Methods: Fifty male war veterans with PTSD and major depression and 50 male non-veterans with depression participated in this study performed at psychiatric outpatient ward in Baqiyatallah hospital during 2008-2009. The patients met the DSM-IV diagnostic criteria. Depression severity, sex, age, educational level, and marital status were matched in both groups. A psychologist completed demographic and Mississippi questionnaires, PTSD checklist (PCL), beck depression Inventory and wechsler memory scale. The collected data were analyzed using SPSS software (version 11.0). A P-value smaller than 0.05 was considered significant.Results: The mean age of the veterans and non-veterans was 43.9±4.7 and 42±9.4 years, respectively. Memory status did not differ between the two groups (P>0.05). There was no statistically significant correlation between duration and severity of PTSD with memory impairment (P>0.05). A negative correlation was found between personal and general information with re-experiencing in the veterans (P<0.05). Impaired memory was correlated with age greater than 45, educational level lower than high school diploma, severity of depression and longer participation in war. Conclusion: Although both PTSD and major depression affected memory, but memory status did not differ between patients with PTSD and depression and patients with chronic depression.
A Comprehensive Numerical Study on Effects of Natural Gas Composition on the Operation of an HCCI Engine Une étude numérique complète sur les effets de la composition du gaz naturel carburant sur le réglage d’un moteur HCCI
Jahanian O.,Jazayeri S. A.
Oil & Gas Science and Technology , 2011, DOI: 10.2516/ogst/2011133
Abstract: Homogeneous Charge Compression Ignition (HCCI) engine is a promising idea to reduce fuel consumption and engine emissions. Natural Gas (NG), usually referred as clean fuel, is an appropriate choice for HCCI engines due to its suitable capability of making homogenous mixture with air. However, varying composition of Natural Gas strongly affects the auto-ignition characteristics of in-cylinder mixture and the performance of the HCCI engine. This paper has focused on the influence of Natural Gas composition on engine operation in HCCI mode. Six different compositions of Natural Gas (including pure methane) have been considered to study the engine performance via a thermo-kinetic zero-dimensional model. The simulation code covers the detailed chemical kinetics of Natural Gas combustion, which includes Zeldovich extended mechanism to evaluate NOx emission. Validations have been made using experimental data from other works to ensure the accuracy needed for comparison study. The equivalence ratio and the compression ratio are held constant but the engine speed and mixture initial temperature are changed for comparison study. Results show that the peak value of pressure/temperature of in-cylinder mixture is dependent of fuel Wobbe number. Furthermore, engine gross indicated power is linearly related to fuel Wobbe number. Gross indicated work, gross mean effective pressure, and NOx are the other parameters utilized to compare the performance of engine using different fuel compositions. Le moteur HCCI (Homogeneous Charge Compression Ignition, ou à allumage par compression d’une charge homogène) est une idée prometteuse pour réduire la consommation de carburant et les émissions polluantes. Le gaz naturel, considéré généralement comme un carburant propre, est un choix approprié pour les moteurs HCCI en raison de sa capacité à former avec l’air un mélange homogène. Cependant, la composition du gaz naturel influe fortement sur les caractéristiques d’auto-inflammation du mélange dans le cylindre et la performance du moteur HCCI. Cet article met l’accent sur l’influence de la composition du gaz naturel sur le fonctionnement du moteur en mode HCCI. Six différentes compositions de gaz naturel (y compris le méthane pur) ont été examinées pour étudier les performances du moteur au moyen d’un modèle thermo-cinétique zéro-dimensionnel. Le code de simulation inclut la cinétique chimique détaillée de la combustion du gaz naturel, y compris le mécanisme étendu de Zeldovich pour évaluer les émissions de NOx. Les résultats ont été validés par comparaison avec des données expérim
The Effects of Price Elasticity Dynamics on a Firm’s Profit
Ali Jazayeri,Narjes Jazayeri
Iranian Journal of Management Studies , 2011,
Abstract: This paper studies the dynamic behavior of price elasticity and its effects on the overall profit.Although price elasticity has a significant effect on sales, its dynamics have not been examined sofar in pricing models. In this paper, a simple pricing model is suggested in which, price elasticity isconsidered dynamic. The suggested pricing model is concerned with a monopolist that its objectiveis to maximize profit by determining the optimal price. Dynamics of price elasticity is described bya quadratic model, with product lifetime as the single dependent variable. By solving the modelusing the theory of optimal control, a system of differential equations is obtained which can be usedto find the optimal price trajectory. Finally, an example is provided to show how the dynamicbehavior of price elasticity can influence the firm's overall profit.
Numerical and Experimental Investigation of Combustion and Knock in a Dual Fuel Gas/Diesel Compression Ignition Engine
A. Gharehghani,S. M. Mirsalim,S. A. Jazayeri
Journal of Combustion , 2012, DOI: 10.1155/2012/504590
Abstract: Conventional compression ignition engines can easily be converted to a dual fuel mode of operation using natural gas as main fuel and diesel oil injection as pilot to initiate the combustion. At the same time, it is possible to increase the output power by increasing the diesel oil percentage. A detailed performance and combustion characteristic analysis of a heavy duty diesel engine has been studied in dual fuel mode of operation where natural gas is used as the main fuel and diesel oil as pilot. The influence of intake pressure and temperature on knock occurrence and the effects of initial swirl ratio on heat release rate, temperature-pressure and emission levels have been investigated in this study. It is shown that an increase in the initial swirl ratio lengthens the delay period for auto-ignition and extends the combustion period while it reduces NOx. There is an optimum value of the initial swirl ratio for a certain mixture intake temperature and pressure conditions that can achieve high thermal efficiency and low NOx emissions while decreases the tendency to knock. Simultaneous increase of intake pressure and initial swirl ratio could be the solution to power loss and knock in dual fuel engine. 1. Introduction Natural gas, because of cleaner nature of its combustion and also lower price compared with conventional liquid fuels, is the most attractive and widely accepted among alternative gaseous fuels. Diesel engines could easily be designed or modified to use natural gas in power production. Due to relative high compression ratio, high thermal efficiency is achievable from these engines. The objective is to increase the percentage of natural gas used as fuel by improving the engine design and combustion process with least exhaust emissions, together with thermal efficiencies compatible with the base engine [1]. There are some problems associated with the diesel engines conversion to dual fuel mode of operation. One of the problems is the knock occurrence at high load operation that the maximum power output of a dual fuel engine is limited by knock and another is the power loss due to lower power density of gaseous fuels. A great deal of numerical research into knock phenomena and power loss in dual fuel engines has been carried out. The combustion models, which are used for investigation, could be divided into two groups: multizone models and multi-dimensional models. Many combustion simulations of dual fuel engines have used multi-zone model to analyze the combustion. Karim simulated autoignition and knock in dual fuel engine using a two-zone
Occurrence of Salmonella enterica Serovar Agona in Oil for Trouts Fish Feed Production Introuts Fishes Farm of Chahar Mahal O Bakhtiari Province of Iran
S. Shekarchian,A. Tavakolli,A. Jazayeri,S. Shekarchian
Research Journal of Biological Sciences , 2012, DOI: 10.3923/rjbsci.2012.102.106
Abstract: Globally, Salmonella is one of the most important food borne pathogens. Even though, bacteria in the genus Salmonella are typical intestinal organisms, they show ability to survive and even multiply in environments other than the intestine, e.g., food and feed. Furthermore, the survival of Salmonella sp., in stored food and feeds are enhanced by a lowered water activity (aw). Some Salmonella serovars such as Agona may occasionally be found in animal feed and its ingredients as well as in the feed production facilities. In the present study, researchers have examined the persistence of Salmonella enterica serovar Agona in an experimentally contaminated marine oil intended for fish feed production. The bacterium was added to the sterile oil in an average concentration of 2x106 Colony Forming Units (CFU mL-1) and kept aerobically at 20°C to mimic common storage conditions. At days 0, 6, 18, 32, 54, 80, 94, 116 and 122, one sample from each of ten parallel aliquots of the oil were examined quantitatively and qualitatively. At day 6 after inoculation, a log increase of viable Salmonella cells could be observed as the average number reached 1.9x107. From day 18-54, the cell numbers were stable at between 1.8 and 3.1x106 cells. After day 54 until the termination of the experiment the number of cells steadily decreased and the bacterium could not be detected by quantitative or qualitative methods at day 122 after inoculation. This experiment demonstrates that Salmonella enterica serovar Agona can survive for at least 4 months in a marine fish oil.
Prevalence and Risk Factors of Gastroesophageal Reflux Disease in Tabriz, Iran
MH Somi,S Farhang,S Nasseri-Moghaddam,ES Jazayeri
Iranian Journal of Public Health , 2008,
Abstract: "nBackground: Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal problems in the west while different reports indicate an increase in the prevalence in Iran. The aim of this study was to estimate the preva-lence and clinical spectrum of GERD in staff of a referral hospital and evaluate the risk factors."nMethods: This cross-sectional study using a modified Mayo clinic questionnaire was performed on staff of Imam Hospi-tal, Tabriz, Iran on a pilot of 50 subjects, and a randomly selected group consisted of 522 subjects in the year 2005. GERD symptoms were defined as at least weekly heartburn and/or acid regurgitation during the past year."nResults: Response rate was 95%. Mean age of responders was 40.02±10.72 yr. The prevalence of recurrent heart-burn and/or acid regurgitation experienced at least weekly and monthly was 26.8% and 34.1%, respectively. They were not related to age and gender. The severity of symptoms was mainly reported of a mild to moderate degree. 45% of the cases reported at least one of the atypical symptoms. There was no relation between marriage status and preva-lence of GERD. On the other hand, GERD was less common among cases with no family history of upper gas-trointestinal disease. The prevalence of frequent GERD was more common among medical staff. Increased BMI (but no recent weight gain or lose) was associated with higher prevalence of GERD symptoms only in women. In-terestingly 33% of our population had a history of using antacid or PPIs which was more among cases with frequent GERD symptoms."nConclusion: This study revealed a high prevalence of frequent GERD symptoms in a selected population of Tabriz. Atypi-cal symptoms should be considered in this area.
"Risk factors in mortality after coronary artery bypass graft - Imam Hospital (1996-1999) "
"Radmehr H,Jazayeri Tehrani S A,Bayatian A,Hatmi Z "
Tehran University Medical Journal , 2002,
Abstract: Introduction: Ischemic heart disease is the most common cause of mortality in developed countries. CABG (Coronary Artery Bypass Graft) is one of the therapeutic methods in ischemic heart disease. Methods and Materials: Considering the increased incidence of coronary artery disease in Iran, and with increased rate of CABG, we performed a cross sectioned study (1996-1999). In 635 patients 467 male (73.5 percent), 168 female (26.5 percent) about risk factors of mortality after CABG in cardiac surgery department "Imam Khomeini hospital. 20 risk factors were included in our study: age, gender, smoking, family history, diabetes mellitus, morbid obesity, hypercholesterolemia, hypertension, palpitation, renal failure COPD, (chronic obstructive pulmonary disease), history of myocardial infarction, CHF, angina, cerebral vascular disease, pace maker, Ejection fraction<40 percent, history of PTCA, history of CPR, and coronary endarterectomy. Results: Cigarette smoking (P=0.40), CHF in female (P=0.003). Endarterectomy in both gender (P=0.0001). Pace maker in both gender (P=0.00006), palpitation in both gender (P=0.0001). CPR in both gender (P=0.0000001), were associated with increased risk of mortality after CABG. Conclusion: We found that, endarterctomy, cigarette smoking, CHF. Pace maker, CPR, and palpitation are important risk factors for mortality after CABG.
N. Izadi Mood,S.N. Jazayeri Z. Eftekhar
Acta Medica Iranica , 2004,
Abstract: The 1991 Bethesda System for cervical/vaginal cytology reporting has defined adequacy criteria, including unsatisfactory designation. Most laboratories in USA and a few laboratories in Iran have implemented these criteria, but only few studies about clinical implications have been performed. All unsatisfactory Papanicolaou (Pap) smears taken between August 2000 and March 2002 were retrieved from the file of cytologic reports of Mirza Koochak Khan Hospital's Department of Pathology. Of 4,598 total Pap smears 204 (4.4%) were unsatisfactory (corresponding atypical rate of 2.5% and a SIL/carcinoma rate of 0.97%). About 20.2% of unsatisfactory Pap smears were from patients with a history of epithelial abnormalities. The majority (71 of 204 specimens; 35%) of follow-up Pap smears or biopsies occurred within 6 months,12% within 6-12 months,1% within 12-18 months and 1% after 18 months. Approximately 59% had no follow-up. The first repeat Pap smear or histologic specimen in 83 patients with follow-up was negative in 71 (85%), unsatisfactory in 2(2.4%), epithelial cell abnormality in 11 (13.2%) and atypical squamous cells of undetermined significance in 4(4.8%). Nonmalignant conditions contributing to the unsatisfactory smears on histologic specimens (23%) included cervicitis, endocervical polyp and endometritis. Majority of patients with unsatisfactory Pap smears were followed up within 6 months. A significant number(13.2%) of those with follow-up had eventual diagnosis of epithelial cell abnormality. Benign pathologic conditions also contributed to unsatisfactory smears. These patients were more likely to have a history of abnormalities. Unsatisfactory specimens are associated with benign as well as preneoplastic/neoplastic conditions. Clinical correlation should be the first step in delineating the cause of the unsatisfactory diagnosis.
Vitamin D Alterations in Food Regimens and Synaptic Transmission in Neuronal Circuit
M Taghizadeh,A Jazayeri,AR Talaei Zavareh,S Davari
Qom University of Medical Sciences Journal , 2012,
Abstract: Background and Objectives: In nervous system, through specific channels and some ionotropic receptors, calcium ion involves in synaptic transmission vitamin D takes an important role in cellular regulation as well. Calcium ion plays an important role in synaptic transmission through specific channels and some receptors such as NMDA receptors in the nervous system. In the present study we asked if alterations in vitamin D content of food regimens influence electrophysiological phenomena in hippocampal neuronal circuits. Methods: Adult rats under normal food regimen (CON), vitamin-D-free regimen (CON-D) or with a supplement of calcitriol (CON+D) were used in this study. Stimulating Schaffer colateral excitatory post synaptic field potentials (EPSP) were recorded in CA1 area of hippocampus. For inducing of long term potentiation (LTP) high frequency stimulation (HFS) was used as a tetanic stimulation. Changes in the amplitude of EPSPs were considered for comparison of the 3 tested groups. Results: Our findings indicated that there was no difference between EPSP amplitude of the CON, CON+D and CON-D rats. On the other hand, LTP was induced only in the CON and CON+D animals. Conclusion: According to the findings, it seems that vitamin D deficiency considerably affect potentiation of the synaptic transmission. The probable mechanism can be vitamin D regulation of intracellular calcium concentration.
Influence of nepheline syenite and milling time on the rheological properties of a porcelain stoneware tile slip
Jazayeri, S. H.,Salem, A.,Timellini, G.,Rastelli, E.
Boletín de la Sociedad Espa?ola de Cerámica y Vidrio , 2003,
Abstract: The rheological properties of porcelain stoneware tile slips were investigated using a rotational rheometer. The first step in the study was to evaluate the rheological behaviour of a reference slip at different particle size distributions to determine the optimum conditions at which to carry out the investigation of the influence of nepheline syenite in the mix. In the second step part of the K-feldspar in the reference mix was replaced with nepheline syenite such that the mix composition contained 10 % nepheline syenite. The flow curve, yield stress and thixotropy of the slips were evaluated at different milling times in order to study the effect of particle size on the rheological behaviour. The milling times for the reference mix and for the mix with nepheline syenite which resulted in the best rheological parameters were found. Se han investigado las propiedades reológicas de barbotinas de porcelana dura para pavimentos usando un reómetro rotacional. El primer paso del estudio fue evaluar el comportamiento reológico de una barbotina de referencia con diferentes distribuciones de tama o de partícula con el fin de determinar las condiciones óptimas bajo las cuales estudiar la influencia de nefelina sienita en la mezcla. En la segunda etapa, parte del feldespato potásico de la mezcla de referencia se substituyó por nefelina sienita de forma que la composición de la mezcla tuviera un 10% de neflina sienita. Se evaluaron las curvas de flujo, los puntos de fluidez y la tixotropía de las barbotinas tras diferentes tiempos de molienda con el fin de estudiar el efecto del tama o de partícula en el comportamiento reológico. Se determinaron los tiempos de molienda en los que se alcanzaban los mejores parámetros reológicos para la mezcla de referencia y la de nefelina sienita.

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