597 research outputs found

    Comparative study on some physiologic, biometrics, nutritional value and molecular characteristics of Mighan Lake’s Artemia (Arak)

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    Due to the importance of identifying the major characteristics of Artemia populations, in this study some physiologic, biometric, nutritional and genetic characteristics of one Artemia population from Iran named Arak’s Artemia (Mighan Lake) was studied. The hatched larvae of Artemia were reared in the saline water of 80 g/l with standards method in which percentage of survival and growth were evaluated on days 3, 7, 11 and 15 of culture period. In order to study the morphometric characteristics of Artemia, diameter of full cysts as well as 11 more morphological parameters of adult Artemia were measured. The fatty acid profile was analyzed by gas chromatography. The Genetic characteristics were compared with other Artemia populations by sequencing after PCR amplification of Hsp 26 gene. According to the results, the diameter of cysts and nauplii instar were 276.28 and 544.66 micron, respectively. The growth and survival of brine shrimp Artemia, in comparison with other populations, reflected good growth and survival of this population. The results of fatty acids profile also showed higher amounts of polyunsaturated fatty acids in this Artemia compared to other populations cultured under identical conditions. The morphometric characteristics and genetic study of Hsp 26 gene showed great affinity of this population with the parthenogenetic brine shrimp Artemia. However, individual differences could be used to characterize this population

    Evaluation of Emotional Intelligence and Job Satisfaction in Employees of Kashan Hospitals

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    Background: Job satisfaction and emotional intelligence are two important variables in organizational behavioral studies, and are key factors in promoting the efficiency of organizations. Objectives: The present study was conducted in order to determine the job satisfaction and emotional intelligence of employees of Kashan hospitals in 2011. Materials and Methods: This cross-sectional study was performed on 121 employees of Kashan hospitals who were selected using random stratified method. In this study, Bar-on emotional intelligence and job satisfaction questionnaires were used. The data were analyzed using statistical methods such as odds ratio, Chi-square and Fisher's exact test. Results: The majority of employees (76%) had moderate emotional intelligence while 88.2% of them had moderate job satisfaction. In this study, there were no significant relations between emotional intelligence and variables such as sex, education, and marital and job status (P > 0.05) but significant relations were found between the age and emotional intelligence (P = 0.01). Furthermore, there was no significant relation between job satisfaction and demographic variables. Moreover, no significant relation was found between the emotional intelligence and job satisfaction (P > 0.05). Conclusions: As the majority of the staff had average level of job satisfaction and emotional intelligence and others were lower than average, it seems necessary for authorities to explore the reasons for job dissatisfaction to prevent job burnout, depression and developing a sense of helplessness in the staff. It is also recommended to hold educational workshops for the staff especially who are younger than 40 years to promote their emotional intelligence

    Application and optimization in chromium-contaminated wastewater treatment of the reverse osmosis technology

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    Background: Chromium (Cr) is the most important element used to plate other metals and electroplating factories are still considered to be the most important industries which pollute the environment to this metal. This paper describes a study conducted to determine the efficiency of reverse-osmosis (RO) as a membrane technique for removal of Cr from wastewater samples synthetically prepared to be similar to electroplating effluents. Methods: The RO unit used in this study was a spiral wound module of 2521 TE made by a Korean CSM company. Synthetic wastewater samples containing Cr ions at various concentrations of 1 to 20 mg/L were prepared and subjected to treatment by RO, and quantitative analysis had been accomplished by a colorimetric method. Evaluation of optimized conditions of treatment had also been carried out by determining the effects of changing operating pressure, temperature and pHs of samples. Results: Optimum conditions of Cr-treatment by RO in 10 g/L initial Cr concentration were determined to be in the pH range of 6 to 7 and in temperature of about 25°C at an applied pressure of 200 psi. Conclusion: Considering the efficiency of Cr removal which was as high as 99 at the optimized conditions it could be concluded that RO membrane process may be selected and developed as an effective alternative for treatment of metal-contaminated effluents of electroplating and similar industries

    Plant glutathione S-transferase classification, structure and evolution

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    Glutathione S-transferases are multifunctional proteins involved in diverse intracellular events such as primary and secondary metabolisms, stress metabolism, herbicide detoxification and plant protection against ozone damages, heavy metals and xenobiotics. The plant glutathione S-transferase superfamily have been subdivided into eight classes. Phi, tau, zeta, theta, lambda, dehydroascorbate reductase and tetrachlorohydroquinone dehalogenase classes are soluble and one class is microsomal. Glutathione S-transferases are mostly soluble cytoplasmic enzymes. To date, the crystal structures of over 200 soluble glutathione S-transferases, present in plants, animals and bacteria have been resolved. The structures of glutathione S-transferase influence its function. Phylogenetic analysis suggests that all soluble glutathione S-transferases have arisen from an ancient progenitor gene, through both convergent and divergent pathways.Key words: Glutathione S-transferases (GST), classification, structure, evolution, phylogenetic analysis, xenobiotics

    An improved liquid chromatography tandem mass spectrometry (LC-MS/MS) method for quantification of dexmedetomidine concentrations in samples of human plasma

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    Dexmedetomidine (DMET) is a sedative, analgesic and anxiolytic with minimum adverse respiratory effects. An LC-MS/MS bioanalytical method has been developed and validated to accurately measure DMET concentrations in samples of human plasma. The method overcomes difficulties in the extraction and quantification of DMET due to the fact that it binds strongly to glass and plastic tubes, as well as solid phase extraction (SPE) cartridges. Human plasma (50 μL) was mixed with the internal standard (IS) (DMET-d4) solution (100 μL) and 0.1% formic acid (50 μL) and extracted using Oasis HLB 1 CC (30 mg) solid phase extraction (SPE) cartridges (Waters®). The glass tubes were coated with bovine serum albumin (BSA) 0.5% (20 μL) before eluting DMET and the IS. After evaporation under nitrogen at room temperature, the analytes were reconstituted in 20% acetonitrile in 0.1% formic acid in water and transferred to silanized glass vials. An electrospray ionisation (ESI) mass spectrometry method in positive mode was created and the precursor/product transitions (m/z) were 201.1 → 95.0 (DMET) and 204.9 → 99.0 (IS). The method was robust and fully validated based on the 2012 EMEA guideline for bioanalytical method validation in the concentration range of 0.5-20 ng/mL. Using this assay, we showed that DMET binds strongly to Extracorporeal Membrane Oxygenation (ECMO) circuits, consistent with expectations for small lipophilic compounds

    The correlation of RNase A enzymatic activity with the changes in the distance between Nepsilon2-His12 and N delta1-His119 upon addition of stabilizing and destabilizing salts.

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    The effect of stabilizing and destabilizing salts on the catalytic behavior of ribonuclease A (RNase A) was investigated at pH 7.5 and 25 degrees C, using spectrophotometric, viscometric and molecular dynamic methods. The changes in the distance between N(epsilon2) of His(12) and N(delta1) of His(119) at the catalytic center of RNase A upon the addition of sodium sulfate, sodium hydrogen sulfate and sodium thiocyanate were evaluated by molecular dynamic methods. The compactness and expansion in terms of Stokes radius of RNase A upon the addition of sulfate ions as kosmotropic salts, and thiocyanate ion as a chaotropic salt, were estimated by viscometric measurements. Enzyme activity was measured using cytidine 2', 3'-cyclic monophosphate as a substrate. The results from the measurements of distances between N(epsilon2) of His(12) and N(delta1) of His(119) and Stokes radius suggest (i) that the presence of sulfate ions decreases the distance between the catalytic His residues and increases the globular compactness, and (ii) that there is an expansion of the enzyme surface as well as elongation of the catalytic center in the presence of thiocyanate ion. These findings are in agreement with activity measurements

    Investigating the skills of integrating Internet tools in teaching by math teachers of secondary schools in Ahvaz first educational district

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    Background and Objectives: Today Internet has a substantial effect on all aspects of human life and has influenced every individual and social aspects. According to studies, more than 82 percent of Iran's population use Internet by the year 2019. Internet as an attractive and pervasive medium has a deep effect on economic, financial, administrative sectors as well as social, cultural, and scientific communications; and somehow has changed people’s lifestyle. This effect has been such that today a concept called digital citizenship is mentioned instead of the traditional concept of citizenship. Since instruction and learning are an important area of human life, reducing the increasing costs of instruction and improving students’ learning and teachers’ teaching have become a main challenge of educational systems, and officials and mangers therefore seek to solve such a problem. Generally, technologies as a new solution open promising windows for educational system administrators. From the advent and development of the Internet as a powerful and interactive tool, it has been at the center of attention of the administrators. The unique nature of the Internet and the fundamental differences with previous media have also attracted the attention of many teachers and professors. Internet provides numerous tools and facilities and could be a desired environment for overcoming challenges. These tools and facilities could be applied in different phases and parts of teaching. Some are appropriate for presenting materials, some for gaining and directing students’ attention, some for doing various practices, and some for doing cooperative and group projects. Therefore, researchers recently have studied how to use Internet tools for various purposes of teaching and learning. Investigating teachers' abilities and capabilities for using Internet tools in teaching and learning has become a main question for researchers. Therefore, the purpose of this study was to investigate the skills of math teachers of secondary schools in Ahvaz to integrate Internet tools in their teaching. Methods: The research method was descriptive survey in which a researcher-made questionnaire was designed. Developed questionnaire consisted of 41 Likert type questions which were divided into 5 categories. 10 questions were related to presenting the material, 9 questions to gaining attention and motivating learners, 13 questions related to designing and developing practices, 4 questions related to providing optimal feedback to learners and finally 5 questions related to facilitating cooperative learning. Reliability of the questionnaire was assessed by alpha coefficient and found to be 0.872. Then expert views were used for assessing the validity of the questionnaire. Statistical population was Ahvaz math teachers and based on the size of the population, all 67 teachers (37 males and 30 females) were selected from high-school teachers. Then the required data was gathered by the questionnaire.  Findings: The results this study indicate that the teachers' skills in using the Internet tools are almost poor. In other words, teachers' skills for presenting the materials (1.62), for gaining attention and motivating learners (1.55), developing practices (1.79), providing optimal feedback to learners (1.72), and for facilitating cooperative learning environment (1.23) were all lower than the assumed mean of the study. Conclusion: Theskills of teachers in integrating Internet tools into teaching including presenting the materials, gaining attention and motivating, developing practices, providing optimal feedback to learners, and for facilitating cooperative learning environment are all poor and need to be improved.   ===================================================================================== COPYRIGHTS  ©2021 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================
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