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211.
Endothelial cell death due to increased reactive oxygen species(ROS) may contribute to the initial endothelial injury,which promotes atherosclerotic lesion formation.Piper sarmentosum(PS),a natural product,has been shown to have an antioxidant property,which is hypothesized to inhibit production of ROS and prevent cell injury.Thus,the present study was designed to determine the effects of PS on the hydrogen peroxide(H2O2)-induced oxidative cell damage in cultured human umbilical vein endothelial cells(HUVECs).In this experiment,HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation(LSGS).HUVECs were treated with various concentrations of H2O2(0-1000 μmol/L) and it was observed that 180 μmol/L H2O2 reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Using the above concentration as the positive control,the H2O2-induced HUVECs were concomitantly treated with various concentrations(100,150,250 and 300 μg/ml) of three different extracts(aqueous,methanol and hexane) of PS.Malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT) and glutathione peroxidase(GPX) levels showed a significant increase(P0.05) in HUVECs compared to the negative control.However,PS extracts showed a protective effect on HUVECs from H2O2-induced cell apoptosis with a significant reduction in MDA,SOD,CAT and GPX levels(P0.05).Furthermore,PS had exhibited ferric reducing antioxidant power with its high phenolic content.Hence,it was concluded that PS plays a beneficial role in reducing oxidative stress in H2O2-induced HUVECs.  相似文献   
212.
This longitudinal case study describes the factors that affect an experienced teacher’s attempt to shift her pedagogical practices in order to implement embedded elements of argument into her science classroom. Research data was accumulated over 2 years through video recordings of science classes. The Reformed Teacher Observation Protocol (RTOP) is an instrument designed to quantify changes in classroom environments as related to reform as defined by the National Research Council (National science education standards. Washington, DC: National Academy Press, 1996b) and the National Research Council (Fulfilling the promise: Biology education in the nation’s schools, Washington, DC: National Academy Press, 1990) and was used to analyze videotaped science lessons. Analysis of the data shows that there was a significant shift in the areas of teacher questioning, and student voice. Several levels of subsequent analysis were completed related to teacher questioning and student voice. The data suggests a relationship between these areas and the implementation of scientific argument. Results indicate that the teacher moved from a traditional, teacher-centered, didactic teaching style to instructional practices that allowed the focus and direction of the lesson to be affected by student voice. This was accomplished by a change in teacher questioning that included a shift from factual recall to more divergent questioning patterns allowing for increased student voice. As student voice increased, students began to investigate ideas, make statements or claims and to support these claims with strong evidence. Finally, students were observed refuting claims in the form of rebuttals. This study informs professional development related to experienced teachers in that it highlights pedagogical issues involved in implementing embedded elements of argument in the elementary classroom.  相似文献   
213.
The paper presents comparative analyses of two publication point systems, The Norwegian and the in-house system from the interdisciplinary Danish Institute of International Studies (DIIS), used as case in the study for publications published 2006, and compares central citation-based indicators with novel publication point indicators (PPIs) that are formalized and exemplified. Two diachronic citation windows are applied: 2006-07 and 2006-08. Web of Science (WoS) as well as Google Scholar (GS) are applied to observe the cite delay and citedness for the different document types published by DIIS, journal articles, book chapters/conference papers and monographs. Journal Crown Indicator (JCI) calculations was based on WoS. Three PPIs are proposed: the Publication Point Ratio (PPR), which measures the sum of obtained publication points over the sum of the ideal points for the same set of documents; the Cumulated Publication Point Indicator (CPPI), which graphically illustrates the cumulated gain of obtained vs. ideal points, both seen as vectors; and the normalized Cumulated Publication Point Index (nCPPI) that represents the cumulated gain of publication success as index values, either graphically or as one overall score for the institution under evaluation.The case study indicates that for smaller interdisciplinary research institutions the cite delay is substantial (2–3 years to obtain a citedness of 50%) when applying WoS for articles. Applying GS implies a shorter delay and much higher citedness for all document types. Statistical significant correlations were only found between WoS and GS and the two publication point systems in between, respectively. The study demonstrates how the nCPPI can be applied to institutions as evaluation tools supplementary to JCI in various combinations, in particular when institutions include humanistic and social science disciplines.  相似文献   
214.
This article describes a collaborative action research conducted by a lecturer and several primary school art teachers, who between 2001 and 2006 created the Visual Arts Education Web (‘iii web’) in Hong Kong. The creation of the ‘iii web’ was accomplished through research that employed questionnaires, focus group discussions and individual interviews. Teachers' perceptions of using websites in teaching were examined, art education websites from Hong Kong, Taiwan, Mainland China and the USA were compared, in order to create a website that could meet the needs of Hong Kong primary school art teachers. Inquiry‐based learning is one of the important teaching approaches that were introduced during the Hong Kong Education Reform in 2003. An example of using the ‘iii web’ to teach public art is described to illustrate how the teacher and students used inquiry‐based learning in art education.  相似文献   
215.
School playgrounds offer everyday opportunities for physically active and social play that combats obesity, develops skills, and promotes well‐being. However, teachers’ fear of the legal consequences of injury can elicit over‐zealous risk reduction with the result that playgrounds lack challenge, and the potential benefits of play become limited. In this research, we trialled a simple, cost‐effective strategy to encourage children to be more active and social on a school playground. Over 11 weeks, we made available materials with no fixed purpose (e.g. car tires, boxes) to a playground of children aged five to seven. Accelerometers showed children became significantly more active. Interviews with teachers suggested children also became more social, creative, and resilient. However, despite no incidence of injuries, teachers perceived an increased risk and encountered dilemmas regarding duty of care. We conclude that future interventions should address issues of ‘surplus safety’ at individual, school, system, and policy levels.  相似文献   
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The success or failure of any tool, service or system used in a library is predicated on the audience it finds. While web-scale discovery systems have developed widespread adoption in academic libraries, there is a sense from librarians that they continue to be in search of their true audience. Librarians play a key role in the utilization of web-scale discovery systems, and their experiences as an end user of these systems may influence their attitudes in many ways. The survey discussed in this article looks at the attitudes librarians have toward web-scale discovery systems when using them for their personal research, including feature preferences and inquiries into opinions regarding strengths and weaknesses of the system. The results of this survey provide some insights into why some librarians struggle with the idea using of web-scale discovery systems by themselves and by the patrons with which they work.  相似文献   
220.
The literature on ethics in higher education tends to focus primarily on the professor/student relationship. While that relationship is central to academia, there are important ethical dimensions to consider in the work of faculty development. Principles used to gloss the ethics of the professor/student relationship are applicable to the ethics of faculty development as well.  相似文献   
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