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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: HPLC,Biogenic Amines,Micellar liquid chromatography,Mixed micelles
- چکیده:
- چکیده انگلیسی: Separation of some biogenic amines via RP-HPLC using mixed micellar mobile phase was investigated. The compounds were derivatized before hand by dansyl chloride as a chromophoric reagent. Appropriate conditions for separation, were determined by studying factors such as temperature, type and percentage of organic modifier, concentration of surfactants (SDS and Brij-35) and the pH of the mobile phase. The number of theoretical plates (N), asymmetry factor (B/A) and selectivity factor (α) considered as criteria for finding the appropriate conditions for separation. Appropriate condition, were: 40˚C, 40 mM SDS, 0.5 mM Brij-35 and 10% 1-propanol at pH=5.
- انتشار مقاله: 20-04-1383
- نویسندگان: Mohammad Reza Hadjmohammadi,Soghra Jafari
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: aromatic compounds,Mixed Micellar Liquid Chromatography (MMLC),Linear Solvation Energy Relationship (LSER),LSER equation in MMLC,Solvation parameter model
- چکیده:
- چکیده انگلیسی: The effect of SDS (0.03-0.07 M) and Brij-35(0-0.003 M) concentrations and temperature on retention parameters of 30 solutes in micellar reversed- phase liquid chromatography systems were studied using solvation parameter model. The system constants were determined by multiple linear regression analysis from experimental values of the retention factors with known descriptors by computer using the program SPSS/PC. The experimental results showed that the variation in concentration of surfactants (SDS, Brij-35) changes the cavity formation (m) and hydrogen-bond acidity (b). The value of m decreases while the value of b increases as the SDS concentration increases. The value of m and b slightly decrease as the Brij-35 concentration increases. Variation of temperature (25-38˚C) showed changes in cavity formation (m) and hydrogen-bond acidity (b). A comparison of the predicted and experimental retention factors indicated a satisfactory agreement between the two. Normalized residual plot showed that the contribution of the systematic modeling errors is approximately minor using the linear solvation energy relationship (LSER) equation. The value of cross-validated r2 was 0.973.
- انتشار مقاله: 24-12-1382
- نویسندگان: Mohammad Reza Hadjmohammadi,Mitra Rezaie
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: High performance liquid chromatography,Sedative-hypnotic drugs,Micellar liquid chromatography,Mixed micellar liquid chromatography,Separation of sedative-hypnotic drugs
- چکیده:
- چکیده انگلیسی: Separation of ten sedative- hypnotic drugs was performed by RP-HPLC using mixed micellar mobile phase. Effect of temperature, type and amount of organic modifier in mobile phase on efficiency (N) and asymmetry factor (B/A) showed that, the appropriate conditions for a good separation were 35°C and 7% (V/V) butanol in mobile phase. Variations of selectivity factor versus butanol concentration, Mixture of SDS/ Brij- 35 concentrations and pH of mobile phase showed that the appropriate conditions were 7%(V/V), 15 mM SDS +1.0mM Brij-35 and pH=3 in mobile phase respectively.
- انتشار مقاله: 22-11-1382
- نویسندگان: Mohammad Reza Hadjmohammadi,Azadeh Shariphi Aghili
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Bioluminescence,Luminometer,Michaelis constant,luciferase,ATP,Photinus pyralis,American firefly
- چکیده:
- چکیده انگلیسی: Effects of ATP and Mg2+ concentrations on bioluminescence reaction of luciferase (Photinus pyralis) were investigated by home-made luminometer. The Michaelis constants of the enzyme for ATP and Mg2+ obtained from the Lineweaver-Burk graph, were 61.9 mM ±3.3 mM and 251.6mM ± 39.0mM respectively. Optimum concentration of Mg2+ for maximum luminescence was 0.004 M.
- انتشار مقاله: 31-03-1377
- نویسندگان: Mohammad Reza Hadjmohammadi,Mohammad Javad Chaichi
- مشاهده
- جایگاه : پژوهشی
- مجله: Biquarterly Iranian Journal of Analytical Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: HPLC,Hollow Fiber Liquid Phase Microextraction,Levocetirizine,Fexofenadine
- چکیده: یک روش ساده، ارزان و موثر برای استخراج و تعیین فکسوفنادین و لووستیریزین در این کار ارائه گردید. روش بر پایه اندازه گیری با استفاده از کروماتوگرافی مایع بعد از میکرواستخراج مایع فیبر توخالی می باشد. چندین پارامتر موثر روی بازیابی های استخراج از جمله طبیعت حلال آلی استخراج کننده، pH فازهای گیرنده و دهنده، سرعت چرخش، زمان استخراج و میزان نمک فاز نمونه (دهنده) بررسی و بهینه سازی شد. در نهایت رنج خطی مناسب 500-1 نانو گرم بر میلی لیتر برای فکسوفنادین و 600-6/0 نانو گرم بر میلی لیتر برای لووستیریزین بدست آمد. حدود تشخیص نیز به ترتیب 3/0 و 2/0 نانوگرم بر میلی لیتر برای فکسوفنادین و لووستیریزین بدست آمد.
- چکیده انگلیسی: A simple, inexpensive and efficient method was used for extraction and determination of Fexofenadine and Levocetirizine with three–phase hollow fiber liquid-phase microextraction and high-performance liquid chromatography. Several parameters influencing the extraction recoveries such as the nature of organic extraction solvent, pH of donor and acceptor phases, stirring rate, extraction time and salt addition to the sample solution (donor phase) were investigated and optimized. Under the optimized conditions (toluene as organic solvent, pHdonor = 2.5, pHacceptor = 12.0, stirring rate of 1000 rpm, extraction time of 30 min, with no salt addition), extraction recoveries were 64% for Fexofenadine and 79% for Levocetirizine. A good clean-up sample with excellent linearities in the range of 1–500 ng/mL for Fexofenadine (R2=0.997) and 0.6-600 ng/mlfor Levocetirizine (R2=0.998) were obtained. The limits of detection were 0.3 ng/mL for Fexofenadine and 0.2 ng/mL for Levocetirizine.
- انتشار مقاله: 30-08-1393
- نویسندگان: Mohammadreza Hadjmohammadi,Maede Asadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Biquarterly Iranian Journal of Analytical Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: HPLC,Hollow Fiber Liquid Phase Microextraction,Loratadine,Human plasma sample
- چکیده: کاربرد فیبر تو خالی مبتنی بر میکرو استخراج فاز مایع برای استخراج و پیش تغلیظ لوراتادین قبل از اندازهگیری با HPLC-UV مورد بررسی قرار گرفت. تحت شرایط بهینه فاکتور بازیابی 308 با انحراف استاندارد نسبی برابر با 8/3 درصد به دست آمد. منحنی کالیبراسیون در رنج 600-3/0 نانو گرم بر میلی لیتر خطی بود. حد آشکارسازی 1/0 نانو گرم بر میلی لیتر به دست آمد. سرانجام اندازهگیری لوراتادین در پلاسمای انسان با استفاده از HF-LPME-HPLC انجام شد، و نشان داد که این روش توانایی تمیز سازی مناسب و فاکتور بازیابی بالایی برای لوراتادین را دارا میباشد.
- چکیده انگلیسی: The applicability of hollow fiber-based liquid phase microextraction (HF-LPME) was evaluated for the extraction and preconcentration of Loratadine prior to determination by HPLC. In order to obtain high extraction recovery, the parameters affecting the HF-LPME including type of organic phase, pH of the source and receiving phases, stirring rate, extraction time and salt addition were studied and optimized. Under the optimized conditions, enrichment factor of 308 with relative standard deviation (R.S.D.%) equel 3.8% were achieved. The calibration curve was linear in the range of 0.3–600 ng/ml with good linearity (R2 = 0.9991). The limit of detection (LOD) was 0.1 ng/ml (based on S/N = 3). Finally, determination of Loratadine in human plasma was used by HF-LPME-HPLC and indicated that this method had an excellent clean-up and high recovery factor (84%) for Loratadine.
- انتشار مقاله: 11-04-1393
- نویسندگان: Mohammad Reza Hadjmohammadi,Maede Asadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Applied Language Studies
- نوع مقاله: Journal Article
- کلمات کلیدی: Blended Learning,ESP,ICT-mediated Learning,Iranian TVT,M-game
- چکیده:
- چکیده انگلیسی: To direct m-game to be a possible didactic option for Iranian TVT (Technical Vocational Training) trainees, in this study m-game-mediated (Mobile Game-Mediated) materials delivery was incorporated into the conventional teaching method in the blended ESP reading skill platform. So, 52 male trainees fromTechnical and Vocational College of Isfahan were selected by convenience sampling. Afterwards, 48 trainees were defined as homogeneous using Englishtag Test to learn ESP in 16 triads under two different blended learning scenarios in 18 sessions in the academic year 2014-2015. While the first group of the trainees practiced in the blended learning situation with ready-made displaying device and materials, the second-group trainees practiced the same content through the medium of their own self-made PDA (Personal Digital Assistant) and materials; in this way, their learning performance assessed continuously in and outside the classroom. To employ tree-prong approach, interest survey and focus-group interview were embraced, as well. Overall, descriptive and inferential analyses of the collected data disclosed that trainees who were involved in the process of materials development were more excited and learned more than their counterparts who practiced via prefabricated devices and materials. Consequently, self-made (vs. prefabricated) m-game-mediated blended platform was found to be more liable to teaching and learning ESP reading skill.
- انتشار مقاله: 03-12-1395
- نویسندگان: Mohammad Javad Mohammadi,Saeed Khazaie,Mohammad Khatib
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Behavioral Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی: Keywords: Positive Psychology,Human Flourishing,Educational-interventional Protocol
- چکیده:
- چکیده انگلیسی: Abstract Introduction: The increasing importance of the movement of positive psychology and consequently positive education has led scientific study to foster and promote human psychological flourishing. This research aimed to provide an educational-interventional protocol to foster and promote flourishing and evaluate its effectiveness. Method: With a pretest and posttest design and a control group, this study was performed on 34 teachers from two schools in Tehran, selected by multi-stage cluster sampling. After randomly allocating teachers to the test and control groups, they complete the Human Psychological Flourishing Scale and Flourishing Questionnaire. Then, the educational-interventional flourishing protocol was only presented to the test group during 14 sessions. The questionnaires were filled again by all the subjects at the end of the course. Results: According to the results of the univariate and multivariate covariance analyses, flourishing training significantly increased all the components of flourishing in the test group, compared to the control group. Conclusion: According to the results, the application of educational-interventional flourishing protocol increased all the components of flourishing among teachers (e.g., positive emotion, relationships, meaning, and accomplishment, sense of satisfaction/happiness, individual competency and social contribution). Therefore, this protocol can be applied to promote the flourishing of teachers.
- انتشار مقاله: 26-12-1398
- نویسندگان: Hanieh Hojabrian,Ali Mohammad Rezaei,Imanollah Bigdeli,Mahmoud Najafy,Mohammad Ali Mohammadifar
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Behavioral Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی: Performance,Keywords: Emotional Job Demands,Emotional Labor,Teaching Satisfaction
- چکیده:
- چکیده انگلیسی: AbstractIntroduction: The aim of the present study was to test the structural model of emotional job demands, teaching satisfaction and the performance of teachers with the mediatory role of emotional labor and the moderator role of emotional intelligence.Method: The participants were 432 (227 first set and 205 second set) teachers of Qazvin which were chosen through stratified random sampling. All of them completed the emotional labor and teaching satisfaction questionnaire of Yin and the performance questionnaire of Paterson. Data were tested through the modeling of structural equations. Findings showed that the measurement model for the emotional labor is valid with three markers of surface action, deep action and natural expression of emotion.Results: Teachers’ understanding of emotional job demands had a direct structural effect on the application of emotional labor strategies by the teachers (GA= -0.28, t = -3.02, P<0.01). Teachers’ understanding of emotional job demands had an indirect effect on the teaching satisfaction through the strategies of emotional labor (Sobel test =3.43, p<0.001). Also, teachers’ understanding of emotional job demands had an indirect effect on teachers’ performance with the mediator role of emotional labor strategies (Sobel test= 3.14, p<0.001). The application of the emotional labor strategies had a direct effect on the teaching satisfaction (BE= -1.09, t= -19.01, P< 0.001) and teachers’ performance (BE= -1.17, t= -5.08, P<0.01). Teaching satisfaction had a direct effect on teachers’ performance (BE= -0.39, t=2.38, P<0.01).Conclusion: Emotional intelligence significantly moderated the structural relationship between teachers’ understanding of emotional job demands, the use of emotional labor strategies, teaching satisfaction and performance. This is while, in this model the measurement of emotional labor did not play a moderator role. Emotional job demands and emotional labor strategies were effective antecedents for performance and teaching satisfaction of teachers, especially teachers with high emotional intelligence. Job satisfaction and performance of the teachers should be studied considering the individual factors such as the emotional job demands, emotional labor strategies and the role that emotional intelligence plays.
- انتشار مقاله: 19-02-1396
- نویسندگان: Maryam Sarraf,Siyavash Talepasand,Eshagh Rahimianboogar,Mohammad Ali Mohammadifar,Mahmoud Najafi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Mining and Geo-Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Uniaxial compressive strength,Behesht-Abad tunnel project,Geostatistical estimation,SGEMS
- چکیده:
- چکیده انگلیسی: Uniaxial compressive strength (UCS) is one of the most significant factors on the stability of underground excavation projects. Most of the time, this factor can be obtained by exploratory boreholes evaluation. Due to the large distance between exploratory boreholes in the majority of geotechnical projects, the application of geostatistical methods has increased as an estimator of rock mass properties. The present paper ties the estimation of UCS values of intact rock to the distance between boreholes of the Behesht-Abad tunnel in central Iran, using SGEMS geostatistical program. Variography showed that UCS estimation of intact rock using geostatistical methods is reasonable. The model establishment and validation was done after assessment that the model was trustworthy. Cross validation proved the high accuracy (98%) and reliability of the model to estimate uniaxial compressive strength. The UCS values were then estimated along the tunnel axis. Moreover, using geostatistical estimation led to better identification of the pros and cons of geotechnical explorations in each location of tunnel route.
- انتشار مقاله: 05-04-1393
- نویسندگان: Mohammad Doustmohammadi,Ahmad Jafari,Omid Asghari
- مشاهده