An evaluation of the depth of similarity between linear and non-linear wave theories

An evaluation of the wave behavior and the effects of kinematics and dynamic properties of wave particles on the submerged members of a jacket platform have been accomplished. The Stokes fifthorder and Airy wave theories have been employed to evaluate the kinematics and dynamic properties of wave particles. SAP2000 software was used to determine and evaluate the wave properties. The aim of this study is to model both theories and determining a depth of water, in which both theories indicate the same behavior. The study has found that the non-linear fifth-order theory shows similar behavior with the linear Airy wave theory from 10 meters below the SWL toward the sea floor with 99% of similarity

Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells

The importance of dye sensitized solar cells (DSSCs) as a low-cost and environmentally friendly photovoltaic (PV) technology has prompted many researchers to improve its efficiency and durability. The realization of these goals is impossible without taking into account the importance of the materials in DSSCs, so the focus on the preparation/deposition methods is essential. These methods can be either chemical or physical. In this study, the chemical applied methods that utilize chemical reaction to synthesize and deposit the materials are covered and categorized according to their gas phase and liquid phase precursors. Film processing techniques that can be used to enhance the materials' properties postpreparation are also included for further evaluation in this study. However, there is a variety of consideration, and certain criteria must be taken into account when selecting a specific deposition method, due to the fact that the fabrication conditions vary and are unoptimized

Evaluation of Agreement Between Video and Written Questionnaires for Asthma Symptoms Among Children of Tehran: ISAAC Study

Introduction: International study on asthma was conducted to study the prevalence of Asthma symptoms among 13-14 year old children using written and video questionnaires during the early 90's. The aim of the present study (ISAAC) was to evaluate the agreement between the two questionnaires which were self-completed by the children. Methods: This study, which was a part of the third phase of International Study of Asthma and Allergy in Childhood (ISAAC) and performed exactly similar to phase1, was performed by National Research Institute of Tuberculosis and Lung Diseases (NRITLD) in two cities of Iran; Rasht and Tehran. All stages of the study were performed in accordance with ISAAC protocol. The present study discusses data related to children of Tehran. A total of 3100 school children aged 13-14 years were questioned about asthma symptoms using written and video questionnaires of ISAAC study. For statistical analysis, initially a descriptive study of the available data was performed. Thereafter, chance corrected agreement between the two questionnaires was evaluated using Cohen’s Kappa co-efficiency. Results: Of the total of 3100 children, 52.4% were male and 47.6% female, with a mean age of 13.6 years. Although the questions discussed in the two questionnaires were not exactly similar, the results of the video questionnaires showed a statistically significant lower positive response to asthma symptoms as compared to the written version. Kappa co-efficiency ranged between 0.06- 0.21 (mean=0.12), which is considered poor for all variables. Conclusion: Positive responses to having asthma symptoms were significantly higher using the written questionnaire compared to the video questionnaire. Similar to previous studies, agreement between the two was considered poor for all variables. Although factors such as language, culture, dwelling area, e.t.c. have special effects on results of these questionnaires, results indicate that the two questionnaires should be further studied and validated for this special group of patients in order to reach a better interpretation of prevalence of asthma symptoms

EVALUATION OF IL1-α AND TNF-α SERUM LEVELS IN RHEUMATOID ARTHRITIS PATIONTS WITH ACTIVE AND INACTIVE, WITH OR WITHOUT BONE EROSION

Rheumatoid arthritis is the most common inflammatory joint disease with 1 percent prevalence in community which presents with symmetrical polyarthritis of hands with inflammatory behavior. Several studies in recent years were conducted for evaluation of inflammatory cytokines such as IL1-α (Interlukin 1α) and TNF- α (Tumor necrosis factor) in rheumatologic disorders including rheumatoid arthritis to find new treatment methods base to pathogenesis. In this study different serum levels of IL1-α and TNF- α in 160 rheumatoid arthritis patients with active and inactive disease and also disease with or without bone erosion are assessed. 4% of our patients had rheumatoid nodule and 70% of all patients had positive RF, IL1-α, and TNF- α levels. Active with bone erosion patients had IL1-α and TNF- α serum levels higher than active without bone erosion patients; it was not significant in T-test but it was significant in Mann-Whitney Test. The results was the same as expected; IL1-α, and TNF- α serum levels were higher in active with bone erosion in comparison with inactive without bone erosion patients

The Correlation of Student's Smoking and Their Perceived Exposure to Their Teacher's Smoking in Tehran: A Population Based Study

Introduction: Smoking approval by friends and teachers seems to increase the probability of smoking by the students. This study aimed to determine whether adolescent smoking is associated with teachers or other students smoking, after controlling for confounders. Methods: A sample of the 3rd grade students of Tehran's high schools were asked to complete a 21 item questionnaire, including demographic and smoking habits. The comparisons of adolescent smoking pattern between two sexes and also smoking frequency of the family members, best friends and teachers between the smoking and non-smoking students, were performed. Furthermore, the association between smoking behavior and exposure to teachers smoking were assessed by a multivariate logistic regression analysis, adjusted for sex, parental, best friends, and sibling smoking. Odds Ratios were estimated. Results: Among the 4591 students (aged 17-19, mean 17.53±0.59 years), including 2092 boys (45.6%) and girls, 250 boys (12.1%) and 131 girls (5.3%) were current smokers (p=0.001). The proportion of smoker and non-smoker students who have been exposed to teachers smoking inside the school building were 55.7% (209) and 29.3% (1191) respectively (p=0.001). The 220 (58.7%) exposed students to outdoors teachers smoking (on school premises) were smoker while 1205 (29.2%) were non-smoker (p=0.001). By adjustment of the parameters, adolescent exposure to best friend smoking and to teachers smoking on school premises was significantly associated with current smoking. Conclusion: Teachers smoking during school hours and best friend smoking are the two important determinants to be considered in any project aiming to establish tobacco-free schools

The Role of Physical Techniques on the Preparation of Photoanodes for Dye Sensitized Solar Cells

Dye sensitized solar cells (DSSCs) have attracted numerous research, especially in the context of enhancing their efficiency and durability, due to the low-cost and environmentally friendly nature of photovoltaic (PV) technology. The materials in DSSCs are vital towards the realization of these goals, since many of the important components are influenced by their respective preparation and deposition methods. This review aims to detail the research and development aspects of the different physical methods with the purpose of evaluating their prospects and corresponding limitations. The diversity of consideration and criteria includes thin film applications, material characteristics, and process technology that need to be taken into account when selecting a specific deposition method. Choosing a deposition method is not as simple as it seems and is rendered quite complicated due to various factors. Usually, a researcher will evaluate techniques based on factors such as the different preparations and deposition technology with materials’ and substrates’ type, specified applications, costs, and efficiencies