27 research outputs found
Educating prospective science teachers in Oman : evaluating initial training programmes
No full textThis study has investigated the effectiveness of an initial teacher training programme
provided by the Omani Colleges of Education in preparing science teachers. To understand
the phenomena of this research, to give a picture as clear as possible of the topic under
study and to determine the information that needs to be collected, a framework was
established.
A combination of qualitative and quantitative tools (questionnaires, interviews and
document examination) was used to meet the aims of this study. The questionnaires and
interviews were designed and tailored to relate specifically to the teachers' competencies
that are required by the Omani Reformed General Education (the Basic Education: Stage
Two). In addition, the importance and effectiveness of the programme's components were
also investigated.
The questionnaires were conducted with all the student science teachers in the final
academic year, 2000/2001, and all the teacher educators in the departments of educational
studies in all the six Omani Colleges of Education. Sub-samples of student teachers and
teacher educators were interviewed. In addition, some newly qualified teachers were also
interviewed.
To carry out a careful analysis, a framework of data analysis was developed. The results
are divided into three main sections. The first section addresses student teachers'
competencies. The second section reports the participants' evaluation of the importance
and effectiveness of the pedagogical courses. The third section covers the respondents'
evaluation of the importance and the effectiveness of practicum aspects. In addition, results
that emerged from the two last open-ended questions in the questionnaires and interviews
and the effects of some variables on student teachers' competencies are presented.
This study has indicated that while student science teachers demonstrated their ability in
some competencies, they were deficient in the majority. In general, the results have
indicated that approximately 86.96% of the competencies were rated to be average whereas
only 10.87% of these competencies were viewed to be above average (i.e. competent). In
addition, the majority of responses indicated that student teachers could use some
experiential learning methods and some different assessment tools to a limited extent but
not effectively. Furthermore, student science teachers are not fully prepared to use a
problem-solving approach and ICT in teaching science.
This research has produced interesting and useful data about the student teachers'
competencies and the curriculum of the colleges and the manner in which it was
implemented. It has not only shown a serious gap between the actual needs of science
teachers (importance) and their preparation (effectiveness) by the colleges but identified
also the areas of weakness. Some factors affecting the acquisition of the student teachers'
competencies are addressed.
Recommendations have been made for the Ministry of Higher Education for the
development of the existing science teacher education programmes, and for the Ministry of
Education (in-service teacher training). Issues for further research are also addresse
Educating prospective science teachers in Oman Evaluating initial training programmes
No full textAvailable from British Library Document Supply Centre- DSC:DXN056242 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Consequences of tyrosine phosphorylation of Syntaxin4 and Munc18c on GLUT4 trafficking
No full textGlucose homeostasis is regulated by the opposing actions of insulin and glucagon; insulin facilitates rapid glucose uptake from the blood stream to muscle and adipose cells. These tissues express the facilitative glucose transporter (GLUT4), which in response to insulin is translocated from intracellular compartments to the plasma membrane (PM) allowing glucose entry to cells. GLUT4 undergoes a complex intracellular trafficking itinerary, including recycling to and from the PM, but in the absence of insulin is mainly stored in GLUT4 storage vesicles (GSVs). When insulin binds its receptor, a complicated signalling cascade is initiated which results in the tethering, docking and fusion of GSVs to the PM. Fusion of the GSVs with the plasma membrane is mediated by SNARE proteins. The formation of a SNARE complex composed of Syntaxin4 (Sx4) and SNAP23 localised to the PM and VAMP2 on GSVs is a key event; the formation of this complex is in turn regulated by the Sec1/Munc18 protein, Munc18c. It has been shown that insulin stimulation leads to phosphorylation of Sx4 at two sites (Y115 and Y251) and Munc18c at Y521. The stoichiometry and order of phosphorylation are not yet known, and the biological consequences of this action to be uncovered. Therefore, the current study sought to ascertain the functional consequences of SNARE protein phosphorylation on GLUT4 trafficking. The approaches used include in vitro assessment of recombinant SNARE proteins and studies in vivo using 3T3-L1 adipocytes.
The results of this study confirmed that tyrosine 115 and 251 of syntaxin4 are phosphorylated in response to insulin in 3T3-L1 adipocytes; however, phosphorylation of Munc18c was ambiguous. Subsequently, phosphomimetic recombinant SNARE proteins were expressed and ternary SNARE complex formation was successfully recapitulated in vitro and the complex found to be SDS and heat resistant. Phosphomimetic syntaxin4 mutants showed increased formation of SNARE complexes, notably double phosphomimetic mutant. Moreover, binary interactions with other SNAREs (SNAP23 and VAMP2) revealed tighter binding and higher affinity of the double phosphomimetic syntaxin4 compared to wild-type syntaxin4. Additional spectroscopic evidences suggest these differences are due to conformational changes and syntaxin4 mutants are more likely to be in the open form especially the double phosphomimetic mutant.
In order to translate in vitro findings into cell models, in vivo intervention tools were generated including phospho-specific antibodies against phosphorylated residues in syntaxin4 and lentivirus particles for 3T3-L1 adipocytes infection. Antibodies validated on recombinant proteins phosphorylated using recombinant insulin receptor tyrosine kinase indicated they are functional and specific. Efforts dedicated towards optimizing working conditions for phospho-specific antibodies using adipocyte lysates were extensively examined, yet signals detected were generally found to be non-specific.
A non-intrusive protein-protein interaction protocol, proximity ligation assay, was used to detect insulin-stimulated phosphorylation in adipocytes. A positive signal was detected confirming antibodies functionality in this assay; further work will be required to optimize this.
Lentiviruses were used to over-express phosphomimetic mutants of syntaxin4 in 3T3-L1 adipocytes and Hela cells. The functionality of the transfected syntaxin4 mutants was assessed by measuring basal and insulin-stimulated glucose uptake. Infected native 3T3-L1 adipocytes showed a trend towards an increase in glucose uptake under basal conditions with no effect observed on the maximal insulin-stimulated rate of glucose transport. We speculate this may reflect the presence of the endogenous Sx4 molecules masking any effects of mutant over-expression thus Sx4 knockout cell lines was considered as an alternative experimental system. Sx4 overexpression rescued insulin-stimulated glucose uptake in Sx4 knockout 3T3-L1 cells and was significantly enhanced in cells expressing the double phosphomimetic mutant.
Finally, our work showed that the native Munc18c native mouse gene sequence expressed poorly in bacteria; hence we used a gene-enhanced sequence that was found to express well and purify effectively. CD spectroscopy showed similar structures of expressed Munc18c using either sequences. Phosphomimetic Munc18c (Y521E) binds with higher affinity both wild type and double phosphomimetic syntaxin4 compared to wild type Munc18c.
The data presented in this study suggest strongly that phosphorylation influences GLUT4 trafficking by altering the frequency and affinity of SNARE protein interactions. Such findings enrich knowledge about the mechanism of GLUT4 trafficking thus ultimately could help in understanding type 2 diabetes
A Novel Splice-site Allelic Variant is Responsible for Wilson Disease in an Omani Family
No full textObjectives: The objective of this study was to characterise Wilson's Disease (WD) [OMIM 277900] genetically and test for allelic variants in the copper transport gene (ATPase, Cu++ transporting, beta polypeptide, ATP7B) responsible for the disease in an Omani family. Methods: Three index patients from an Omani family had been previously diagnosed with WD. All three patients suffered neurological symptoms and signs. Forty-six relatives in the family were screened for WD. Eleven more individuals were positive, but asymptomatic. Results: Thirteen non-disease-causing allelic gene variants, described previously, were identified in the ATP7B gene from 46 family members. A putative novel disease-causing splice-site variant (c.2866-2A>G), which has not been reported previously, was detected in this family. It is located upstream of exon 13 which encodes part of transmembrane copper channel (Ch/Tm6). Reverse transcription polymerase chain reaction was used to amplify a complementary DNA (cDNA) fragment containing exons 12, 13 and 14. Exon 13 was entirely skipped from the transcript which probably would result in a defective ATP7B protein. Conclusion: A new ATP7B splice-site allelic variant, found among the 14 WD patients segregated with the disease in a recessive manner, suggests it is a disease-causing variant
Characteristics of Al-Alloy/Seashell (SESB) Composites in Acidic and Alkaline Environments
No full textThe corrosion behaviour of Al-alloy/Seashell (SeSh) composites in the acidic and alkaline environment was investigated in this study. Fifteen Aluminum alloy composites samples were produced using stir casting technology by varying the amount of reinforcement (1.5, 3.0, 4.5, 6.0, 7.5 wt%) and particle size (100, 150, 200 µm) of milled SeSh in the Aluminium alloy matrix. The corrosion rate was determined using a weight loss technique after 18 days of immersion at an interval of 72 hours. It was observed that 6.0 wt% of the 100 µm reinforced Aluminium alloy had the best corrosion resistance in acidic and alkaline environments. In general, the reinforced Al-alloy had better corrosion resistance when compared with the unreinforced samples. Analyses of the results show that aluminum alloy seashell composites exhibited better resistance to corrosion in the alkaline environment than the acidic environment
SNARE phosphorylation: a control mechanism for insulin-stimulated glucose transport and other regulated exocytic events
No full textTrafficking within eukaryotic cells is a complex and highly regulated process; events such as recycling of plasma membrane receptors, formation of multivesicular bodies, regulated release of hormones and delivery of proteins to membranes all require directionality and specificity. The underpinning processes, including cargo selection, membrane fusion, trafficking flow and timing, are controlled by a variety of molecular mechanisms and engage multiple families of lipids and proteins. Here, we will focus on control of trafficking processes via the action of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) family of proteins, in particular their regulation by phosphorylation. We will describe how these proteins are controlled in a range of regulated trafficking events, with particular emphasis on the insulin-stimulated delivery of glucose transporters to the surface of adipose and muscle cells. Here, we focus on a few examples of SNARE phosphorylation which exemplify distinct ways in which SNARE machinery phosphorylation may regulate membrane fusion
A Study on FTIR, Antimicrobial, Antioxidant and Hypogycaemic Effect of Diospyros Kaki and Citrullus colocynthis
No full textPhytochemical, FTIR screening, Hypoglycemic study, antibacterial, antifungal and antioxidant activity of Citrullus colocynthis and D. kaki fruit were studied. The interest of this study is to evaluate traditional herbal usage to treat many diseases around the sultanate of Oman locally. The functional groups that they contain are (O-H) Phenol, (C-H) Alkyl, (N-H) Amine and (C=C) Alkenyl groups corresponds to their biological phytoconstituents responsible for the medicinal properties. The antibacterial and antifungal activities revealed that all parts of tested samples shown good antimicrobial properties. While leaf of C. colocynthis methanolic extract showed highest zone of inhibition (24.33 mm³) against penicillium. Antioxidant assays were evaluated through DPPH (1, 1- diphenyl-2-picryllhydrazyi) and H2O2 (Hydrogen peroxide scavenging capacity) methods. Peel of D. kaki extract showed higher antioxidant activities than other parts. Antioxidant property of these fruit is due to the presence of significant amount of tannins, phenolic acids and flavonoids on them. A slight change in body weight was observed in all mice compared to the control. All extracts except leaf of C. colocynthis show significant reduction in blood glucose level even more than the positive control which treated with metformin drug. From our investigation of screening different parts of two plants, the results obtained confirm the therapeutic value of both plants used in traditional medicine
أثر تقنية الواقع المعزز على دافعية تلاميذ الصف الخامس نحو كتاب مقرر تقنية المعلومات في سلطنة عمان = The impact of augmented reality technology on the motivation of fifth grade students towards the information technology course book in the Sultanate of Oman
No full textThe aim of this research is to find the effectiveness of augmented reality technology (augmented book) on students' motivation towards their textbook (reading and applying) represented in the information technology course for this research. The research was designed on the quasi-experimental approach based on two groups (control - experimental), the control group (171) and the experimental group (179) students from the fifth grade students in government schools in the Sultanate of Oman. The observation card was used as a tool to reveal the hypothesis of the study, which assumed the presence of Statistically significant differences at the function (α ≤ 0.05) between the two groups. The results of the study showed that there were statistically significant differences at the function (α ≤ 0.05) between the control group and the experimental group in favor of the experimental group with an average effect on the total total. The researcher recommended the adoption of technology in some parts of the course to motivate students to investigate the textbook
Electronic Nicotine Delivery Systems Exhibit LowerToxicity Compared to Cigarettes: "The Replica Study Experience"
No full textPhenotypic plasticity of leaf shape in selected and semi-domesticated genotypes as new tool of Argania spinosa L. Skeels breeding
No full textArticle Details: Received: 2020-03-28 | Accepted: 2020-05-22 | Available online: 2020-09-30 https://doi.org/10.15414/afz.2020.23.03.125-138Leaves are part of the plant organs that are important to sustain its life. These organs are sensitive to climate changes and may present phenotypic plasticity in response to environmental conditions. However, affirmation of the leaves morphological plasticity and their regulation in different environments is still little studied up to date. In the present research, we evaluated performance of 20 different groups of Argania spinosa (L.) Skeels genotypes (half-sibling). Each group contains 3 half-sibs. Genotype × environment interactions (GxE) were evaluated as well, for shape and size leaves. To perform this, geometric morphometric principles were applied to analyze genotypes morphology in three locations (Central, North-Western and South-Western of Morocco). Univariate and multivariate analysis was used for data analysis. Results showed significant variation of symmetric and asymmetric components for genotypes, half-sibling and location with relatively high variation coefficient (ca 60%). Shape and size differences among genotypes, suggest that they were the main source in leaf morphology variation. Canonical Variate Analysis of leaf shapes reveals that the regions are clearly distinct from each other. For symmetric component analysis, Mahalanobis distances values among locations reached 35.53 between South-Western and North-Western locations, 21.88 North-Western and Central locations and 18.29 for South-Western and Central location. The differentiation between the groups using the Canonical Variations value showed a significant effect of the environment on the studied argan tree genotypes. Small leaves and narrow blades were observed in Central location compared to others. However, leaves originated from South-Western location had mainly an ovate shape. 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