Effect of methyl mercury induced free radical stress on nucleic acids and protein: Implications on cognitive and motor functions     

Farhana Zahir  Shameem J Rizvi  Soghra K Haq  Rizwan H Khan 《Indian journal of clinical biochemistry : IJCB》2006,21(2):149-152

Mercury pollution and acute neurotoxicity of mercury is well known. The recent reports suggest the adverse effect of low dose mercury, though the available literature is still silent on its mechanism. This study was therefore undertaken to probe the effect of low dose methyl mercury induced heavy metal toxicity on free radical stress and its impact on behaviour of male albino rats. Male albino rats were exposed to 1 mg/kg body wt of methylmercury chloride for seven days, on day 8 they were tested for motor and memory functions. They were sacrificed later for biochemical estimations for rate of lipid peroxidation, nucleic acids, proteins in cerebrum, cerebellum and brain stem. There was an increase in the rate of lipid peroxidation showing methyl mercury induced free radical stress. The motor and memory functions demonstrated a clear decline, besides there was a lowering in the levels of nucleic acids and proteins as compared to controls. The results are important in view of recent reports that methyl mercury induced free radical stress results in early ageing and may serve as an initiating factor more specifically for neurodegenerative disorders like Alzeihemer's disease and dementias. The current findings support the notion that incorporating dietary antioxidants like curcumin, ascorbic acid and α-tocopherol in routine diet from early age may help combat the risk of developing such disorders in ensuing years.  相似文献   

Use of digital game based learning and gamification in secondary school science: The effect on student engagement,learning and gender difference     

Amna Khan  Farzana Hayat Ahmad  Muhammad Muddassir Malik 《Education and Information Technologies》2017,22(6):2767-2804

This study aimed to identify the impact of a game based learning (GBL) application using computer technologies on student engagement in secondary school science classrooms. The literature reveals that conventional Science teaching techniques (teacher-centered lecture and teaching), which foster rote learning among students, are one of the major concerns in Pakistan Education system. This leads to student disengagement in science lessons eventually resulting in student absenteeism and dropouts from the schools. This study consisted of five stages: (1) examining the impact of Digital Game-Based Learning (DGBL) and gamification on engagement, learning and gender difference, and literature related to using DGBL models for instructional design; (2) planning learning activities and developing a GBL application based on a specific content in Science; (3) conducting an intervention with a sample of 72 participants of 8th grade (aged 12–15) in a low cost private school of Pakistan following quasi-experimental research framework; (4) observing behaviour and emotions of the participants during science lessons; (5) conducting pre and post tests to assess the learning outcomes of participants followed by focus groups discussion. Analysis from Friedman test, Mann-Whitney U test, and Wilcoxon Signed Rank test show that the GBL application has a positive influence on student engagement. However, GBL application was not equally effective for all students since girls outperformed boys in terms of engagement and learning outcomes. This study gives insights into the development of better educational games to promote student learning.  相似文献   

The spread of private tutoring in English in developing societies: exploring students’ perceptions     

M. Obaidul Hamid  Asaduzzaman Khan  M. Monjurul Islam 《Discourse: Studies in the Cultural Politics of Education》2018,39(6):868-886

ABSTRACT

Although research on private tutoring has gained visibility in recent years, private tutoring in English (PT-E) has not received notable attention. This paper examines students’ perceptions of PT-E in Bangladesh in terms of its necessity and helpfulness, peer pressure in PT-E participation and ethicality of PT-E practice and government intervention. Our analysis of survey data (N?=?572) leads to characterising PT-E and explaining the reasons for its popularity. As a popular learning space beyond formal schooling, PT-E is available in various forms and quality catering to the purchasing power of different social groups. We argue that students may resort to PT-E not because of its proven effectiveness but because of their declining faith in school English teaching. The paper contributes to our understanding of the complex interactions between the curricular (school) and non-curricular (PT-E) settings and family socioeconomic resources in the teaching of English as a globally desired language.  相似文献   

Evaluating research performance of research institutes within Malaysian universities: an alternative assessment framework     

Ta  Goh Choo  Halim  Sharina Abdul  Azman  Norzaini  Komoo  Ibrahim  Mokhtar  Mazlin 《Tertiary Education and Management》2021,27(4):331-349

Tertiary Education and Management - Evaluation of research performance has significantly increased in importance, particularly in many emerging higher education systems. In Malaysia, the Malaysian...  相似文献   

Pengajaran Mengarang     

Tengah b Abdul Latif 《Asia Pacific Journal of Education》1978,1(1):32-33

Penguasaan bahasa seakan-akan tidak memerlukan usaha sama sekali. Pendapat ini kuranglah benar. Hal yang sebenarnya ialah, bahawa setelah bertahun-tahun dengan latihan yang tidak jemujemu dan kesalahan yang dibetulkan berulang-ulang secara eksplisit dan implisit barulah akhimya kanakkanak itu dapat menyesuaikan bahasa orang dewasa. Kepada manusia pula pada umumnya penguasaan bahasa itu merupakan suatu prestasi yang luarbiasa selama hidupnya.  相似文献   

A framework for web-based learning     

Badrul H. Khan 《TechTrends》2000,44(3):51-51

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Glial cells: The other cells of the nervous system     

Yasmin Khan  Medha S. Rajadhyaksha 《Resonance》2002,7(6):6-13

Neuroscientists have believed for a long time that glial cells are supportive elements of the nervous system and have little role in neuronal function. Despite outnumbering neurons tenfold in the Central Nervous System (CNS), and contributing to more than half the brain volume, not much attention was paid to these cells. Recently, glial cells have been found to be far more active participants in CNS function. A set of glial cells, the oligodendrocytes, has attracted attention as their precursors have been found to be extremely plastic. Though these precursor cells are initially committed to form oligodendrocytes alone, they can also be induced to form astrocytes and neurons. Such examples of transdetermination are opening up new lines of research with immense clinical implications. In this part of the series we review some aspects of oligodendrocyte structure and function.  相似文献   

Mycorrhizoremediation an enhanced form of phytoremediation   总被引：2，自引：0，他引：2  

Khan AG 《Journal of Zhejiang University. Science. B》2006,7(7):503-514

Study of plant roots and the diversity of soil micro biota, such as bacteria, fungi and microfauna associated with them, is important for understanding the ecological complexities between diverse plants, microbes, soil and climates and their role in phytoremediation of contaminated soils. The arbuscular mycorrhizal fungi （AMF） are universal and ubiquitous rhizosphere mi- croflora forming symbiosis with plant roots and acting as biofertilizers, bioprotactants, and biodegraders. In addition to AMF, soils also contain various antagonistic and beneficial bacteria such as root pathogens, plant growth promoting rhizobacteria including free-living and symbiotic N-fixers, and mycorrhiza helping bacteria. Their potential role in phytoremediation of heavy metal （HM） contaminated soils and water is becoming evident although there is need to completely understand the ecological complexities of the plant-microbe-soil interactions and their better exploitation as consortia in remediation strategies employed for contaminated soils. These multitrophic root microbial associations deserve multi-disciplinary investigations using molecular, biochemical, and physiological techniques. Ecosystem restoration of heavy metal contaminated soils practices need to incorporate microbial biotechnology research and development. This review highlights the ecological complexity and diversity of plant-microbe-soil combinations, particularly AM and provides an overview on the recent developments in this area. It also discusses the role AMF play in phytorestoration of HM contaminated soils, i.e. mycorrhizoremediation.  相似文献   

Effects of audiotutorial and conventional instructional techniques on cognitive achievements     

Abdul G. Khan 《科学教学研究杂志》1980,17(1):47-53

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Urinary iodine levels in three ecological zones of Bangladesh     

Salamatullah Quazi  M. Mohiduzzaman  Moududur R. Khan  B. Nahar  M. Mostafizur Rahman  M. Nurul Islam  M. Baquer  Chandrakant S. Pandav  Harun K. M. Yusuf 《Indian journal of clinical biochemistry : IJCB》1997,12(2):128-133

Urinary iodine levels in children (5–11 years) and in adult males and females (15–44 years) of three ecological zones (hilly, flood-prone and plains) of Bangladesh were analyzed to determine the status of biochemical iodine deficiency in the country. Data indicated that a large majority of the population all over Bangladesh have biochemical iodine deficiency urinary iodine excretion (UIE) less than the accepted cut-off level of 10 μg/dl. Adults were deficient to comparable degrees, 31.3% severely iodine deficient. The flood-prone zone was less affected: 71.7% children had iodine deficiency and 25% were severely deficient. Adults of this zone were less affected than the children. Iodine deficiency was least severe in the plain zone: 59.8% children were biochemically iodine deficient and of them 23.4% had UIE less than 2.0 μg/dl. In the case of the adults of this zone, 60.8% were biochemically iodine deficient and 20.6% had severe iodine deficiency. The results indicate that Bangladesh as a whole is an iodine deficient region, with the hilly zone being the most severely affected. Children were slightly more affected than the adults, and females were more affected than the males.  相似文献