排序方式： 共有48条查询结果，搜索用时 15 毫秒
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Hasan Ebrahimi Shahmabadi Seyed Kazem Bagherpour Doun Seyed Ebrahim Alavi Mehri Mortazavi Zahra Saffari Maryam Farahnak Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2014,29(3):357-361
Emulsion polymerization was used to synthesize poly butyl cyanoacrylate nanoparticles in presence of steric stabilizer dextran 70. Nanoparticles were characterized by particle size analysis, scanning electron microscopy and light microscopy. Polymerization factors affecting particle size and distribution such as dextran 70, polysorbate 80 (PS 80) and H+ concentration, polymerization time and temperature, and sonication were studied. Distinct concentrations of stabilizer were needed to produce proper nanoparticles. In this case, the appropriate value was 2 % of total volume. At pH 4 significant decrease in production efficiency demonstrated the substantial effect of H+ concentration on nanoparticles. Furthermore significant increases in particle size and distribution was observed at 50 °C compared to room temperature. 0.001 % (v/v) PS 80 represented notable influence on size and distribution. In addition, shaped nanoparticles were obtained by altering polymerization time from 5.5 h to 18 h. Finally, nanoparticle features were influenced by different factors. Appropriate manipulating of such factors can lead to obtaining desirable nanoparticles. 相似文献
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Amit Kumar Mani Tiwari Abbas Ali Mahdi Fatima Zahra Sudarshna Sharma Mahendra Pal Singh Negi 《Indian journal of clinical biochemistry : IJCB》2012,27(3):246-252
To correlate blood lead levels (BLLs) and oxidative stress parameters in pregnant anemic women. A total of 175 pregnant women were found suitable and included for this study. Following WHO criteria, 50 each were identified as non-anemic, mild anemic and moderate anemic and 25 were severe anemic. The age of all study subjects ranged from 24–41 years. At admission, BLLs and oxidative stress parameters were estimated as per standard protocols and subjected with ANOVA, Pearson correlation analysis and cluster analysis. Results showed significantly (p < 0.01) high BLLs, zinc protoporphyrin (ZPP), oxidized glutathione (GSSG), lipid peroxide (LPO) levels while low delta aminolevulinic acid dehydratase (δ-ALAD), iron (Fe), selenium (Se), zinc (Zn), haemoglobin (Hb), haematocrit (Hct), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), red blood cell (RBC) count, reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (TAC) in all groups of anemic pregnant women as compared with non anemic pregnant women. In all groups of pregnant women, BLLs showed significant (p < 0.01) and direct association with ZPP, GSSG and LPO while inverse relation with δ-ALAD, Fe, Se, Zn, Hb, Hct, MCV, MCH, MCHC, RBC, GSH, SOD, CAT and TAC. Study concluded that low BLLs perturb oxidant-antioxidant balance and negatively affected hematological parameters which may eventually Pb to Fe deficiency anemia during pregnancy. 相似文献
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Over recent decades, educators have recognized the crucial importance of teaching environment and contextual factors in teaching
and learning outcomes. Public and private schools are among those teaching contexts that have been in competition for teaching
quality and effectiveness for many years. This study investigated the effectiveness of some English teachers in these two
school contexts in a foreign language setting, Iran. Seventy-six public and private high schools in a small city in Iran were
selected, and their English teachers’ performance was evaluated by an external observer and self-evaluation using a high-inference
observation instrument and a questionnaire. The result of the data analysis showed that English teachers who worked in private
schools were more effective teachers than their colleagues in public schools. The results also revealed that teacher effectiveness
and their years of teaching experience and age were weakly but significantly related. Furthermore, it was found that teachers’
type of university degree and the location of schools (disadvantaged vs. privileged areas of the city) were not related to
teachers’ effectiveness. 相似文献
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Transnational corporations in education: filling the governance gap through new social norms and market multilateralism? 总被引：1，自引：0，他引：1
Zahra Bhanji 《Globalisation, Societies & Education》2008,6(1):55-73
This paper explores the rising presence of transnational corporations (TNCs) in education and their mobilisation of global corporate social discourses to legitimise their private authority in education. The rising presence of TNCs is explored in the paper in two parts. First, through a taxonomy of global corporate social engagement (GCSE) activities and second, through a case study of the World Economic Forum’s corporate citizenship initiatives as a new form of ‘market’ multilateralism in education. Lastly, I critique the GCSE efforts of TNCs working in education and discuss the implications of their seemingly ‘to do good’ activities. 相似文献
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Essa ALI Nazim HUSSAIN Imran Haider SHAMSI Zahra JABEEN Muzammil Hussain SIDDIQUI Li-xi JIANG 《Journal of Zhejiang University. Science. B》2018,(2)
目的:本研究目的在于了解:(1)喷施外源茉莉酸对受到镉胁迫油菜的作用;(2)是否茉莉酸能够通过增强气体交换,从而保护受到氧化胁迫的地上部分组织的叶绿体,进而通过减少镉的吸收来维持离子平衡;(3)是否通过喷施茉莉酸来对具有减缓镉毒害效应的抗氧化酶的活性进行调节。创新点:茉莉酸能够调节响应胁迫的抗氧化酶的活性,从而通过保护叶绿体免受活性氧(ROS)伤害而提高光合产物的能力,最大限度地缓解油菜植株受到的镉毒害。方法:(1)叶片气体交换;(2)叶片光合色素分析;(3)丙二醛与抗氧化酶活性分析;(4)营养成分分析;(5)透射电镜亚细胞水平观察。结论:茉莉酸对于植物受镉毒害的缓解作用的机理在于减少叶片中镉的积累,从而减轻氧化胁迫过程中产生的ROS对于膜系统的损害程度。 相似文献
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Nazim Hussain Hui Li Yu-xiao Jiang Zahra Jabeen Imran Haider Shamsi Essa Ali Li-xi Jiang 《Journal of Zhejiang University. Science. B》2014,15(2):181-193
Tocopherols (Tocs) are vital scavengers of reactive oxygen species (ROS) and important seed oil quality indicators. Nitrogen (N) is one of the most important fertilizers in promoting biomass and grain yield in crop production. However, the effect of different sources and application rates of N on seed Toc contents in oilseed rape is poorly understood. In this study, pot trials were conducted to evaluate the effect of two sources of N fertilizer (urea and ammonium nitrate). Each source was applied to five oilseed rape genotypes (Zheshuang 72, Jiu-Er-1358, Zheshuang 758, Shiralee, and Pakola) at three different application rates (0.41 g/pot (N1), 0.81 g/pot (N2), and 1.20 g/pot (N3)). Results indicated that urea increased α-, γ-, and total Toc (T-Toc) more than did ammonium nitrate. N3 was proven as the most efficient application rate, which yielded high contents of γ-Toc and T-Toc. Highly significant correlations were observed between Toc isomers, T-Toc, and α-/γ-Toc ratio. These results clearly demonstrate that N sources and application rates significantly affect seed Toc contents in oilseed rape. 相似文献
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ABSTRACT The present qualitative study explores the beliefs of Iranian early childhood English teachers regarding their roles in teaching English as a foreign language (EFL) to young learners at kindergarten and preschool age. The data were collected through classroom observations and interviews with 13 Iranian EFL kindergarten teachers who volunteered to participate in this study. More specifically, after initial introductory interviews with each participant, their classes were observed, and subsequently, verbal recollection interviews were conducted. Depending on the various administrative constraints at different kindergartens, each participant was observed two to four sessions, 36 sessions in total. Three major themes representing beliefs of the participants emerged from thematic analysis of the interview data. The themes included teachers’ beliefs about, first, the constraints affecting early childhood methodologies and pedagogical practices; second, the influence of English language on children’s native language, culture, and, identity; and third, the attempts required for achieving an ideal early childhood EFL instruction. As such, these results may provide potential implications for policy makers and curriculum designers responsible in this field to encourage reforms in kindergartens’ instructional, administrative, and marketing policies. 相似文献
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Remy Dou Eric Brewe Geoff Potvin Justyna P. Zwolak Zahra Hazari 《International Journal of Science Education》2018,40(13):1587-1605
Modeling Instruction (MI), an active-learning introductory physics curriculum, has been shown to improve student academic success. Peer-to-peer interactions play a salient role in the MI classroom. Their impact on student interest and self-efficacy – preeminent constructs of various career theories – has not been thoroughly explored. Our examination of three undergraduate MI courses (N?=?221) revealed a decrease in students’ physics self-efficacy, physics interest, and general science interest. We found a positive link from physics interest to self-efficacy, and a negative relationship between science interest and self-efficacy. We tested structural equation models confirming that student interactions make positive contributions to self-efficacy. This study frames students’ classroom interactions within broader career theory frameworks and suggests nuanced considerations regarding interest and self-efficacy constructs in the context of undergraduate active-learning science courses. 相似文献