排序方式： 共有78条查询结果，搜索用时 15 毫秒
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Neda Dadgar Maedeh Koohi Moftakhari Esfahani Sepideh Torabi Seyed Ebrahim Alavi Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2014,29(4):501-504
This study is aimed to investigate the nanoliposomal artemisinin preparation, and its implementation on breast cancer cells. Side effects have been one of the common challenges of drug usage, as well as cancer treatment. In order to reduce such effects, nanotechnology has been a great help. Nanoliposomes are provided through reverse phase evaporation. In this method, certain proportions of phosphatidylcholine, cholesterol and artemisinin were mixed together. Besides, the obtained formulation was pegylated by using polyethylene glycol 2000 in order to increase its stability and solubility. The mean diameter of non-pegylated and pegylated liposomal artemisinin was determined by Zeta sizer system. The percent of drug released from liposome was performed by dialysis. The encapsulation efficiency of both formulations was estimated by spectrophotometry method. As a result, encapsulation and drug release of nanoliposomal formulation were more than the pegylation of the same formulation. In addition, this study indicated that cytotoxicity effect of pegylated nanoliposomal artemisinin was more, in comparison with nanoliposomal artemisinin. 相似文献
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Seyed Ebrahim Alavi Maedeh Koohi Moftakhari Esfahani Fatemeh Alavi Fatemeh Movahedi Azim Akbarzadeh 《Indian journal of clinical biochemistry : IJCB》2013,28(3):299-302
It is clear that cancer is one of the most mortal diseases in the world and the most prevalent among women is breast cancer. As hydroxyurea (HU)—a drug which is used in chemotherapy—has many adverse effects in long-term despite of its therapeutic properties, we made use of nano drug delivery technology in order to reduce adverse effects and increase therapeutic index. Thus, liposomation is a novel way in drug delivery systems. In this study a mixture of phosphatidylcholine and cholesterol was mixed and HU was added to the resultant mixture. The mean diameter of the nanoliposomal HU measured with the Zeta Sizer device (equal to 402.5 nm) and its encapsulation efficiency was 70.8 %. Besides, using dialysis, the pattern of drug release from nanoliposomes has been studied and the results showed that the drug release of nanoliposomal drug within 28 h was equal to 25.85 %. This study showed that the cytotoxicity effect of nanoliposomal drug is more than that of the standard drug. 相似文献
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Tamer G. Amin 《International Journal of Science Education》2015,37(5-6):966-991
Many of the goals of research on conceptual metaphor in science education overlap with the goals of research on conceptual change. The relevance of a conceptual metaphor perspective to the study of conceptual change has already been discussed. However, a substantial body of literature on conceptual metaphor in science education has now emerged. This work has not yet been synthesized or related explicitly to the goals of conceptual change research. This paper first presents a broad sketch of the study of conceptual change, characterizing the goals of this body of work, its contributions to date, and identifying open questions. Next, the literature on conceptual metaphor in science education is reviewed against this background. The review clarifies the natural theoretical connections between the conceptual metaphor perspective and the phenomenon of conceptual change. It then examines the contributions made by the literature on conceptual metaphor in science education to the goals of research on conceptual change—namely, characterizing student conceptions, identifying obstacles to learning, understanding the process of conceptual change, and designing productive pedagogical strategies that could achieve conceptual change. The paper concludes with a discussion of further avenues for research into conceptual change, suggested by adopting a conceptual metaphor perspective. 相似文献
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Despite the significant role of oral presentation in the academic context, many university students evade opportunities for participation due to low self-efficacy. The present study has been conducted to compare oral presentation self-efficacy of English as a Foreign Language (EFL) learners with undergraduates and postgraduates of Non-EFL majors, and to investigate the relationship of this construct with their teaching and prior academic oral presentation experiences as two modes of Bandura’s [(1995). Exercise of personal and collective efficacy in changing societies. In A. Bandura (Ed.), Self-efficacy in changing societies (pp. 1–45). New York: Cambridge University Press] mastery experience. Extracting the oral presentation sub-skills from the literature, an oral presentation self-efficacy questionnaire with 38 five-Likert scale items was constructed. A two-way between-group ANOVA was run on the responses of a total 48 postgraduates (25 EFL and 23 Non-EFL) and 63 undergraduates (28 EFL and 35 Non-EFL) selected randomly from two of the universities in Iran. The results indicated no difference between EFL and Non-EFL students, whether at undergraduate or postgraduate level, in terms of their oral presentation self-efficacy. Spearman’s correlation coefficient, however, showed a strong positive correlation between the two modes of mastery experience and oral presentation self-efficacy (r?=?.44, n?=?111, P?r?=?.42, n?=?111, P?相似文献
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This paper examines three methods to measure the upper arm rotation, the main contributor to produce a fast first serve in
tennis. Accepted videography techniques were compared with a novel inertial gyroscope system and marker-based technique. A
network of two inertial sensors on the upper arm and the chest was used to measure upper arm rotation angle and remove body
artifacts. A marker-based virtual gyroscope (MBVG) was derived from Vicon marker positions in the standard Plug-in-Gait model
using a vector-based method of marker trajectories and a series of geometric transformations. The results indicate that there
is a close temporal feature match for all three methods when applied to the tennis serve. This paper shows that gyroscopes
as well as the MBVG can be advantageous for tennis serve assessment. 相似文献
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Amanda P. Montgomery Amin Mousavi Michael Carbonaro Denyse V. Hayward William Dunn 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):114-127
Blended learning (BL) is a popular e-Learning model in higher education that has the potential to take advantage of learning analytics (LA) to support student learning. This study utilized LA to investigate fourth-year undergraduates' (n = 157) use of self-regulated learning (SRL) within the online components of a previously unexamined BL discipline, Music Teacher Education. SRL behaviors were captured unobtrusively in real time through students' interaction with course materials in Moodle. Categorized by function: (1) activating—online access location, day-of-the-week, time-of-day; (2) sustaining—online frequency; and (3) structuring—online regularity and exam review patterns, all six SRL behaviors were revealed to have weak to moderate significant relationships with academic achievement. Results indicated access day-of-the-week and access frequency as the strongest predictors for student success. Findings regarding access regularity when viewed through results from previous SRL-LA research may suggest the importance of this SRL behavior for successful students within several BL discipline areas. In addition, the role of learning design (eg, flipped instruction) in potentially scaffolding students' choices toward specific SRL behaviors, was revealed as an important context for future researchers' consideration. 相似文献
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Reza Gharibi Amir Hossein Rasekh Mohammad Hadi Sadreddini Seyed Mostafa Fakhrahmad 《Information processing & management》2018,54(6):1058-1076
Bug reports are an essential part of a software project's life cycle since resolving them improves the project's quality. When a new bug report is received, developers usually need to reproduce the bug and perform code review to locate the bug and assign it to be fixed. However, the huge number of bug reports and the increasing size of software projects make this process tedious and time-consuming. To solve this issue, bug localization techniques try to rank all the source files of a project with respect to how likely they are to contain a bug. This process reduces the search space of source files and helps developers to find relevant source files quicker. In this paper, we propose a multi-component bug localization approach that leverages different textual properties of bug reports and source files as well as the relations between previously fixed bug reports and a newly received one. Our approach uses information retrieval, textual matching, stack trace analysis, and multi-label classification to improve the performance of bug localization. We evaluate the performance of the proposed approach on three open source software projects (i.e., AspectJ, SWT, and ZXing) and the results show that it can rank appropriate source files for more than 52% of bugs by recommending only one source file and 78% by recommending ten files. It also improves the MRR and MAP values compared to several existing state-of-the-art bug localization approaches. 相似文献
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