فهرست مطالب سعید اسدپور

The purpose of the current research is to compare Context-based Curriculum of Sciences in Junior Secondary Schools of Iran and selected countries. The countries of the England , Netherlands, and United States of America were chosen based on their pioneers in the field of science education and according to the strategy of "different social systems, different educational outputs". Also, the four-stage Bereday’s model was used to analyze and compare the data. In order to increase the validity and reliability of the data, the original documents and self-assessment were used respectively. The findings of research indicated that the most important similarities between four selected countries are strengthening scientific literacy, acquiring process skills and understanding science concepts. The most important difference between the selected countries is use of different contexts and approaches in implementing the curriculum. Also, the comparison between Iran and the selected countries reveal that the similarities are more in the intended curriculum and differences in the implemented curriculum. In fact, in Iran's educational system, the appropriate framework and necessary arrangements for the implementation of the curriculum have not been prepared. Weakness in implementation has been effected Iran's acquired curriculum. Another finding of the research highlighted that there is no consistency between the three planned, implemented and acquired curricula in Iran. It is suggested to the curriculum planners of Iran to pay more attention to the role of teacher in designing the curriculum, role of the student in the learning process, and also the evaluation process of the curriculum

Water is the source of life and the main building block of the universe, which is also the most consumed beverage in the world. Water contains various ions, such as nitrate, nitrite, fluoride, sulfate, chloride, calcium, magnesium, etc. Further, the type and amount of species in water might affect water quality and human health. Today, the high amount of nitrate in drinking water is one of the main public concerns in the health section. Therefore, World Health Organization (WHO) and National Standard Organization of Iran have set the permissible nitrate levels in drinking water at 45 and 50 mg/L, respectively. Nitrate removal from drinking water is necessary to ensure the supply of safe water and prevent the spread of various diseases affected by high amounts of nitrate. In the human body, nitrate has reduced to nitrites that are combined with hemoglobin, which then leads to the making of methemoglobin, which is deadly for babies. Long exposure to nitrate and nitrite leads to the formation of the carcinogenic compound nitrosamine. On the other hand, nitrate affects the size and function of the thyroid gland. Based on the initial quality of water, the level of application scale, the conditions of access to materials and equipment, the cost of the method, and the Type of application of water consumption, different methods are used for nitrification.To investigate the methods used to reduce or remove nitrate ions from water, a comprehensive study was conducted on the basis of reports and research of various scientists in the last two decades. The collected reports were categorized and the characteristics of each method were precisely evaluated separately. Then, the advantages and disadvantages of each method were compared with other methods presented. The most important methods for nitrate reduction are as follows: Ion exchange, Reverse osmosis, Adsorption, Electrodialysis, Chemical, and Biological method. Each of these techniques has its own advantages and disadvantages and different factors, such as economic explanation, industrial application, efficiency, selectivity, and lack of polluting the environment determine the selective method.Among the various methods, the ion exchange method is an effective, simple, relatively low-cost method to reduce the amount of nitrate in water that has good efficiency, especially for low volume water sources. This method involves passing water containing nitrate through a resin bed consisting of anion exchange resins in which the nitrate ion is exchanged with anions such as chloride and has a removal efficiency of more than 90%. In addition to salts and ions, the reverse osmosis method can remove suspended solids, organic matter, colloids, bacteria, and viruses. Generally, reverse osmosis units in the pressure range of 300 to 1500 psi might remove nitrate ions from water. In addition to the mentioned method, ease of execution and uncomplicated design have made adsorption a cost-effective method for nitrate removal. Furthermore, various chemical processes, including electrochemical reduction methods, are used to remove nitrate ions. In these methods, common reducing agents such as active metals, ammonia, borohydride, formate, hydrazine, hydroxylamine, hydrogen, and iron are used.The electrodialysis method purifies water by selectively removing undesirable ions through a semipermeable membrane. In this method, the reduction of nitrate concentration strongly depends on the applied current. The results showed that the optimal current of 20 volts and a concentration of 500 mM electrolyte leads to a significant increase in nitrate removal.The biological method of nitrate reduction is based on the use of nitrate-free microbes, which uses nitrate as the final electron receptor, organic and inorganic materials as electron donors, and energy sources as a way to maintain microbial growth. Bio nitrification is of two types: heterotrophic and autotrophic. The heterotrophic nitrification method is more economical than the autotrophic method on a larger scale and has the possibility of reducing nitrate to nitrogen gas with higher selectivity.The need to reduce or eliminate nitrate from drinking water to prevent various diseases in humans is an important factor in studying and updating nitrate removal techniques. In this study, an attempt was made to offer a variety of methods for nitrate removal, their mechanism, examples of studies, reflecting the properties, and finally, a brief comparison of methods, to provide a basis for studies to introduce and innovate in nitrate reduction techniques. An appropriate understanding of the features of the methods used will save time and cost, improve results, and observe the standards of the World Health Organization. After reviewing and comparing the studied methods, it would be stated that Ion exchange, Reverse osmosis and Electrodialysis are more efficient, compared with other methods, to remove nitrate from drinking water. High efficiency, being user-friendly, environmental considerations, and using at industrial scale are among the most favorable and common properties of these methods.

The present study was conducted with the aim of designing and validating the context-based curriculum model with emphasis on connectivism for teaching sciences in the first period of high school. The method of the study is mixed and exploratory design. In the qualitative part, the directional qualitative content analysis method was used and in the quantitative part, the polling method was used. Data were collected through upstream documents and scientific texts in the period of 2000-2020 and semi-structured interviews using purposive sampling and snowball sampling with 10 experts. The method of data analysis  in the qualitative part was inductive coding and in quantitative part was confirmatory factor analysis, descriptive indices of mean and standard deviation and Kendall inferential test(w). After achieving the proposed model, through a researcher-made questionnaire, 30 experts were interviewed by purposive sampling to validate the model. Among the results obtained in this study, 72 pivotal codes related to the characteristics of the elements of logic, purpose, content, teacher role, learning activities, grouping, resources, time, place and evaluation. In quantitative part, after confirmatory factor analysis of the questionnaire by PLS structural equation software, 2 variable were removed from the original model due to having a factor load of less than 0.5 and a revised model of curriculum with 70 variables was validated and presented after confirmatory factor analysis and appropriate fit by R2 and also examining the agreement of experts with Kendall coefficient.

In this study, prediction of average lethal dose of important drugs for children using molecular descriptors and application of Quantitative Structure-Activity Relationship (QSAR) models by Multiple Linear Regression (MLR) and Artificial Neural Network (ANN) models have been investigated separately. After getting a lot of descriptors the Stepwise regression method was used to reduce the number of descriptors (variables) and the best results were obtained with 8 descriptors. Multivariate linear regression model was then used to predict the lethal dose of the drugs, which yielded almost good results and the parameters R2, Q2 and RMSE for this model were calculated and reported as 0.894, 12.15 and 0.882, respectively. Also by using artificial neural network a better model with correlation coefficients of training, test, validation and total groups were calculated 0.984, 0.994, 0.999 and 0.983, respectively, indicating good validity of this method for Predicting the lethal dose of other similar drugs for children.

The aim of this study has been to evaluate the impact of teaching science with context-based approach on the achievement of seventh grade students in Baharestan city. It was a quasi-experimental study with pretest - posttest design. The research population consisted of secondary school 7th grade male students studying in the first semester of Baharestan city in 1392. The sample consisted of 67 7th grade male students who were selected based on access sampling method. They were divided into two groups of control (34 students) and experimental (33 students). Measurement tools used in the study included IQ test and achievement test (knowledge, skills and attitudes) based on 7th grade science course materials. At first, the achievement test was administered in both the experimental and control groups. Then, the experimental variable (context-based instruction) was trained to the experimental group for 12 sessions and finally the post-test was distributed in both groups. To analyze the data, descriptive statistics (mean, standard deviation) and inferential statistics (covariance) was used. The results showed that the experimental group who were trained with context-based approach has more achievement than control group who were trained with traditional approach. Also, there was a significant difference between the mean score of the two groups. Findings showed that teaching science with context-based approach had positive impact on attitudes, knowledge and skills of students.

Psoriasis is a common chronic skin disease which usually appears as white and silvery spots on the skin. The purpose of this study is to investigate the effect of berberine on patients with psoriasis. This double-blind clinical trial was conducted on 60 psoriasis patients who referred to Imam Khomeini Hospital, Ahvoaz, between July and December 2011. The patients were randomly divided into two equal groups that applied berberine and placebo to the treatment of their lesions twice a day. Lesions severity rate in the patients was assessed 7 times using a Psoriasis Area Severity Index (PASI). Data were analyzed by ANOVA with repeated measurements and Chi-square using SPSS software. After 6 months, severity of lesions showed a significant decrease in the group receiving the berberine cream compared with the placebo group so that the mean PASI score of the group receiving berberine decreased from 3.99 to 2.11 while in the placebo group this decreased from 3.98 to 3.71. Mean difference in PASI score was not significant before receiving the treatment till the third month in berberine and placebo groups, but in the fourth to sixth months it was statistically significant (p=0.013). Berberine cream was more effective than the placebo in reduction of skin lesions of psoriasis patients. Therefore, it is recommended that plant-based drugs, like berberine, be used more besides the main medications of patients.

Nosocomial infections especially in ICUs are common infections and large numbers of patients suffer from these problems in these wards, annually. Therefore, this study has been done to assess nosocomial infections in intensive care unit of Ahvaz Arya hospital. This cross-sectional study was conducted on 772 ICU patients in Ahvaz Arya hospital from 2008 to 2009. Data collected based on National Nosocomial Infections Surveillance System (NNIS). Patients regularly controlled clinically and if infection is suspected based on clinical symptoms and criteria mentioned in NNIS, the necessary tests and cultures were performed. Data were analyzed by SPSS statistical software and chi-square test in significance level of P-value <0.05. 10% of hospitalized patients in ICU, had symptoms of nosocomial infections and the highest rate was in patients over 60 years. Based on type of infection, 41% was urinary tract infection, 28% was respiratory infection, 20.5% reported surgical site infection and 10.5% related to blood infection (sepsis). To reduce hospital infections, it is recommended early diagnosis of infections, continuous assessment of existing microorganisms and their sensitivity and resistance against drugs, establish especial interventions for prevention the spread of hospital infections and health education.