893 research outputs found

    The knowledge and the attitude of youth couples on/towards consanguineous marriages in the north of Iran

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    Aim: Consanguinity is an important risk factor in genetic diseases and in congenital malformations. This study was done to assess the knowledge and the attitude of youth couples on/towards consanguineous marriages in the north of Iran. Material and Methods: This descriptive-analytic study was carried out on 250 young people (125 couples) in Northern Iran during the year 2008. The information was obtained by a direct interview and the questionnaire included four sections which comprised of 39 closed questions. The data was analyzed by using SPSS, version 11.5 and the Chi-Square test. Results: Consanguineous marriages were observed in 32.5% of the couples. Consanguineous marriages were determined in 20.87% and 11.63% of the rural and the urban residents respectively. The knowledge of the youth was poor (49.2% of the females and 40% of the males) on the genetic consequences of inbreeding. The results on the attitude of youths showed that 38.8% of the subjects had agreed and that 61.2% of them had disagreed on consanguineous marriages. There was a significant association between the knowledge of the youths and their attitudes towards consanguineous marriages with their ethnicity, education and residency (p<0.05). Conclusions: This study showed that the knowledge of the youth couples towards consanguineous marriages was poor. Health education programs are needed to improve the knowledge of the youth couples on consanguineous marriages; that they are a potential risk factor in congenital malformations and in genetic diseases in the offspring

    Epidemiology of neural tube defects in northern Iran, 1998-2003

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    We determined the rates of neural tube defects at a referral hospital in Gorgan, north Islamic Republic of Iran, and the relations of these abnormalities to sex, maternal ethnicity, maternal age and season. During 1998-2003, there were 109 cases among 37951 births, a prevalence of 28.7 per 10000 (24.8 and 32.8 per 10000 among males and females respectively). The rates in Turkmen, native Fars and Sistani ethnic groups were 40.5, 25.2 and 30.8 per 10000 respectively. The rates of spina bifida and anencephaly were 16.3 and 11.3 per 10000 respectively. The rate of affected newborns was highest in mothers aged over 35 years (50.7 per 10000). The peak prevalence was in December

    Relationship between p53 expression and gastric cancers in cardia and antrum

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    Background: The mutations in p53 gene and accumulation of p53 protein are the most common genetic events in gastric carcinomas. The present study was conducted to compare the frequency of p53 gene overexpression in a consecutive series of adenocarcinomas arising from the cardia and the antrum. This study also evaluates the associations of this gene expression with demographic and clinicopathologic findings (age, sex, histology, and grade of tumor). Methods: Retrospective analysis was performed on 111 patients with gastric cancer who had undergone upper gastrointestinal endoscopies in 5th Azar Medical Center (northeastern, Iran), during 1998-2005. The series comprised of 25 patients with cardia adenocarcinoma and 86 patients with antral adenocarcinoma. p53 alteration (nuclear p53 overexpression) was detected by immunohistochemistry. Results: Nuclear p53 overexpression was found in 14 (56%) out of the 25 and 27 (31.3%) out of the 86 patients with cardia and antral adenocarcinomas, respectively. p53 gene overexpression was significantly more frequent in adenocarcinomas of the cardia than the antrum. There were no differences in the clinicopathologic characteristics of the tumors between p53-positive and p53-negative cases in both types of the cancer. Conclusion: This study shows that p53 alterations correlate well with gastric location, and they are more frequent in adenocarcinoma of the cardia than the antrum. This result reinforce the hypothesis that the cancers of the lower esophagus and upper stomach have distinct epidemiologic, pathogenesis, and molecular characteristics from that observed in cancers of the lower part of the stomach

    Methods to break seed dormancy of Astragalus cyclophyllon

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    The aim of this study was to enhance the germination rate of Astragalus cyclophyllon seeds which have a very low germination rate under normal conditions. The seeds were soaked for 72 h in 100, 200, 300,400 and 500 ppm gibberellic acid (GA3) solution, H2SO4 concentrations (50 and 98%) at two treatment times (5 and 10 min) and 60, 80 and 100ÂșC hot water at two treatment times (5 and 10 min) beforeplacing in Petri dishes. The fresh seeds (non-stratified) of A. cyclophyllon had 55% germination. Analysis of variance indicated that both GA3 and H2SO4 concentrations had significant effects on seed germination and final germination percentage. The highest germination percentage (81%) was obtained when the seeds were treated with 500 ppm GA3. The results showed that hot water treatments are not useful methods for breaking the seeds dormancy

    Modeling and Controlling a Hybrid Multi-Agent based Microgrid in Presence of Different Physical and Cyber Components

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    This dissertation starts with modeling of two different and important parts of the distribution power systems, i.e. distribution line and photovoltaic (PV) systems. Firstly, it studies different approximation methods and develops a new approach for simplification of Carson\u27s equations to model distribution lines for unbalanced power flow and short circuit analysis. The results of applying the proposed method on a three-phase unbalanced distribution system are compared with different existing methods as well as actual impedance values obtained from numerical integration method. Then steady state modeling and optimal placing of multiple PV system are investigated in order to reduce the total loss in the system. The results show the effectiveness of the proposed method in minimizing the total loss in a distribution power system.;The dissertation starts the discussion about microgrid modeling and control by implementing a novel frequency control approach in a microgrid. This study has been carried out step by step by modeling different part of the power system and proposing different algorithms. Firstly, the application of Renewable Energy Sources (RES) accompanied with Energy Storage Systems (ESS) in a hybrid system is studied in the presence of Distributed Generation (DG) resources in Load Frequency Control (LFC) problem of microgrid power system with significant penetration of wind speed disturbances. The next step is to investigate the effect of PHEVs in modelling and controlling the microgid. Therefore, system with different penetrations of PHEVs and different stochastic behaviors of PHEVs is modeled. Different kinds of control approaches, including PI control as conventional method and proposed optimal LQR and dynamic programming methods, have been utilized and the results have been compared with each other. Then, Multi Agent System (MAS) is utilized as a control solution which contributes the cyber aspects of microgrid system. The modeled microgrid along with dynamic models of different components is implemented in a centralized multi-agent based structure. The robustness of the proposed controller has been tested against different frequency changes including cyber attack implications with different timing and severity. New attack detection through learning method is also proposed and tested. The results show improvement in frequency response of the microgrid system using the proposed control method and defense strategy against cyber attacks.;Finally, a new multi-agent based control method along with an advanced secondary voltage and frequency control using Particle Swarm Optimization (PSO) and Adaptive Dynamic Programming (ADP) is proposed and tested in the modeled microgrid considering nonlinear heterogeneous dynamic models of DGs. The results are shown and compared with conventional control approaches and different multi-agent structures. It is observed that the results are improved by using the new multi-agent structure and secondary control method.;In summary, contributions of this dissertation center in three main topics. Firstly, new accurate methods for modeling the distribution line impedance and PV system is developed. Then advanced control and defense strategy method for frequency regulation against cyber intrusions and load changes in a microgrid is proposed. Finally, a new hierarchical multi-agent based control algorithm is designed for secondary voltage and frequency control of the microgrid. (Abstract shortened by ProQuest.)

    Dynamics and Control of Fiber-Elastomer Composites embedded with Shape Memory Alloys

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    Soft robots have been used in a wide range of applications from robotic and mechanical engineering to medicine and biomededical field. The growing interest in soft robots comes from their good performance in environments which is not best suited for conventional rigid bodies. Soft robots utilize the compliance, adaptability and flexibility of soft materials and actuation methods to develop highly adaptive structures. Among the soft materials, elastomers are specially popular due to their wide range of elasticity and viscoelasticity. Along with elastomers, textile fabrics are also of high interest for soft robotic applications due to their bendable, flexible, and often stretchable nature. The reinforcement of elastomers with textile fibers results in so-called integrated fiber-elastomer composites (IFEC) which offer a wide variety of properties such as flexibility, strength, fracture toughness and damage resistance. The elastic properties of textile reinforced composites require smart actuators which possess adaptability and deformability. Among existing smart actuators, shape memory alloys (SMA) have been frequently adopted in flexible structures including soft robots. SMAs have sensing and actuation capabilities and are characterized by flexibility and lightness which facilitates their integration into these structures. In this dissertation, the modeling and control of soft prototypes made of IFEC are presented. Shape memory alloys are embedded in the composites for the system actuation. First, the mechanical design and production of three IFEC prototypes are described. For each prototype, a test bench including power and control electronics set-up is designed. Next, mathematical models are developed to analyze the dynamic behavior of the prototypes. The IFEC systems exhibit highly nonlinear behaviour due to SMA hysteresis. For modeling, two different approaches, namely physical modelling and system identification are adopted. In physical modeling, the SMA constitutive and heat transfer equations are incorporated with the composite deflection model. To fully develop the equations, thermal and mechanical parameters of SMA wires are identified experimentally. In the second approach, the mathematical model of the systems is derived from experimental identification and unstructured uncertainty models. Two different control techniques are proposed to compensate the nonlinear behavior of the systems and ensure a robust, fast and precise position tracking. In the first control technique, a proportional integral (PI) controller is designed through robust stability analysis. The second controller is a multivariable PI control which is designed for the prototypes that can move in more than one direction. The performance of the controllers are examined experimentally

    Serum copper concentration in newborns with neural tube defects in northern Iran; A case control study

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    Objective: This study was conducted to determine the eventual association between copper deficiency in newborns with neural tube defects (NTD) in Northern Iran. A high prevalence of neural tube defects has been reported from this region. Methods: This hospital based case control study was carried out on 13 newborns having neural tube defects and 35 healthy controls in Northern Iran during 2005-2006. Serum copper was measured by spectrophotometery. Findings: Serum copper level in newborns with NTD and healthy normal newborns was 16.5 (±7.2) Όmol/l and 16.7 (±6.6) Όmol/ l, respectively. In case group 38.5% of newborns and in control group 28.6% had copper deficiency. Logistic regression analysis showed no association between the presence of NTD and copper deficiency (OR:1.6, 95% CI=0.3-7.1, P=0.5). Conclusion: This study showed no association between NTD and copper deficiency in newborns. © 2009 by Center of Excellence for Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, All rights reserved

    Bladder Cancer Detection Using Electrical Impedance Technique (Tabriz Mark 1)

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    Bladder cancer is the fourth most common malignant neoplasm in men and the eighth in women. Bladder pathology is usually investigated visually by cystoscopy. In this technique, biopsies are obtained from the suspected area and then, after needed procedure, the diagnostic information can be taken. This is a relatively difficult procedure and is associated with discomfort for the patient and morbidity. Therefore, the electrical impedance spectroscopy (EIS), a minimally invasive screening technique, can be used to separate malignant areas from nonmalignant areas in the urinary bladder. The feasibility of adapting this technique to screen for bladder cancer and abnormalities during cystoscopy has been explored and compared with histopathological evaluation of urinary bladder lesions. Ex vivo studies were carried out in this study by using a total of 30 measured points from malignant and 100 measured points from non-malignant areas of patients bladders in terms of their biopsy reports matching to the electrical impedance measurements. In all measurements, the impedivity of malignant area of bladder tissue was significantly higher than the impedivity of non-malignant area this tissue (P < 0.005)

    The role of IL-6 for predicting neonatal sepsis: A systematic review and meta-analysis

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    Objective: Neonatal sepsis (NS) is a common and life-threatening disorder in infants. Previous studies showed that interleukin-6 (IL-6) may be a valid non-invasive and rapid method for diagnosis of NS. We conducted this review to assess the validity of IL-6 for predicting NS. Methods: This was a systematic review with meta-analysis. Embase, Medline and Web of Science databases were searched between January 1990 and December 2009. The search terms used were "cytokine", "neonate", "sepsis" and "interleukin-6". We used standard methods recommended for meta analyses of diagnostic test evaluations. The analysis was based on a summary ROC (SROC) curve. Meta-regression analysis was used to assess the effects of some confounding factors on the results of meta-analysis. Potential presence of publication bias was tested using funnel plots and the Egger test. Findings: Meta-analysis was performed on 13 publications including 353 infants with sepsis and 691 control infants. The pooled sensitivity and specificity of IL-6 was 0.79 and 0.84, respectively. The maximum joint sensitivity and specificity (i.e., the Q value) in SROC curve was 0.82 and the area under curve (AUC) was 0.89 (95% CI: 0.84-0.94). Meta-regression analysis showed that the diagnostic accuracy of IL-6 was not affected by confounding variables. The evaluation of publication bias showed that the Egger test was not significant (P=0.07). Conclusion: IL-6 seems to be a valid marker for predicting NS. It may be considered for early diagnosis of sepsis in neonatal care units. © 2011 by Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, All rights reserved

    Healthcare utilization in patients with esophageal cancer in a high risk area in northeast of Iran

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    Introduction: Golestan, a province located north of Persian Gulf in northeastern part of Iran is a well known area for high risk of esophageal cancer (EC) in the world. There is no information about healthcare utilization in populations residing in the area. This study was conducted to assess utilization of healthcare and its associated factors among esophageal cancer patients in this region as well as to address ethical implication of this utilization. Methods: All new cases of EC in Golestan province during year of 2007 were recruited. Seven diagnostic and five therapeutic services were used to assess diagnostic utilization index (DUI), and therapeutic utilization index (TUI), respectively. Multivariate regression analysis was used to assess the relationship between variables and DUI or TUI. P-value of less than 0.05 was considered as statistically significant. Results: Tow hundred twenty three, patients were enrolled with mean (Standard Deviation) age of 64.3 (12.5) years with 57.8% male. We observed that occupation (P<0.01), ethnicity (P<0.01) and sex (P=0.03) were strongly associated with DUI. Insurance coverage (P<0.01), place of residency (P<0.01), and occupation (P=0.01) were associated with TUI. Conclusion: We concluded that several factors contribute to disparity in healthcare utilization in the studied population
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