Sensing Escherichia coli O157：H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

By means of the specific immuno-recognition and ultra-sensitive mass detection, a quartz crystal microbalance (QCM) biosensor for Escherichia coli O157H7 detection was developed in this work. As a suitable surfactant, 16-mercaptohexadecanoic acid (MHDA) was introduced onto the Au surface of QCM, and then self-assembled with N-hydroxysuccinimide (NHS) raster as a reactive intermediate to provide an active interface for the specific antibody immobilization. The binding of target bacteria with the immobilized antibodies decreased the sensor's resonant frequency, and the frequency shift was correlated to the bacterial concentration. The stepwise assembly of the immunosensor was characterized by means of the electrochemical techniques. Using the immersion-dry-immersion procedure, this QCM biosensor could detect 2.0×102 colony forming units (CFU)/ml E. coli O157H7. In order to reduce the fabrication time, a polyelectrolyte layer-by-layer self-assembly (LBL-SA) method was adopted for fast construction. Finally, the reproducibility of this biosensor was discussed.     

噬菌体鸡尾酒制剂对牛奶中产志贺毒素大肠杆菌O157:H7的抑制作用

目的:研究噬菌体鸡尾酒混合制剂对牛奶中产志贺毒素大肠杆菌O157:H7的抑制作用研究.方法:采用双层平板法,以产志贺毒素大肠杆菌O157:H7 ATCC 43895为宿主菌,从污水中分离裂解性噬菌体.通过体外抑菌试验研究其在牛奶样品中的抑菌效果.结果:噬菌体C13.6、C13.9和C34.6的噬菌斑透亮清晰;能裂解宿主菌ATCC 43895及其他O157:H7大肠杆菌,为宽宿主谱;噬菌体鸡尾酒混合制剂对牛奶中O157:H7大肠杆菌的抑菌效果为:在25℃条件下,MOI=10,处理2 h及以上抑菌效果极其显著,在10 h时宿主菌数量下降4.30(lg(CFU/mL)).结论:该噬菌体混合制剂对牛奶中O157:H7大肠杆菌有良好的抑制作用,具有作为食品防腐剂的潜能.     

基于自组装及纳米磁球放大的大肠杆菌O157：H7的压电免疫检测

应用压电免疫传感器快速检测了大肠杆菌O157:H7(E．coli O157:H7)．将巯基乙酸(MACA)自组装在AT切向的压电金电极上,以N-羟基琥珀酰亚胺(NHS)为反应介质,形成酰氨键固定大肠杆菌抗体．并通过α-甲基丙烯酸(MAA)把抗体修饰在纳米磁球上,采用夹心法将抗原夹在两个抗体间,压电石英晶体交流阻抗(PQCI)和循环伏安法对修饰过程进行了表征,抗原浓度与形成夹心复合物前后的PQCI振动频移相关,其免疫传感器能在3h内检测2×103-8×108CFU／mL范围内的目标细茵,105CFU／mL情况下重复性实验的RSD在7％以下。     

Contexts of mentoring and opportunities for learning to teach: a comparative study of mentoring practice

Drawing on data from twenty-three US, UK, and Chinese mentor teachers, this study explores the relationship between contexts of mentoring and mentoring practice. It discusses learning opportunities created by mentoring in different contexts for novices to learn to teach. Through comparative analysis, it finds that mentoring practices show greater differences across programs and countries than within. This is the case even when mentors are practicing or moving toward practicing a kind of teaching as expected by education reformers. These differences are reflected in mentors’ beliefs about what novices need to learn, their interaction patterns and foci with novices. Three instructional contexts in each setting shape such differences: structure of school curriculum and assessment, organization of teaching and mentoring, and student population. These findings suggest that the reform-minded teaching practice that mentors developed does not necessarily guarantee the effective mentoring that supports teacher learning and teaching reform. Teacher educators should pay attention to the influences of instructional contexts on mentoring and the kinds of learning opportunities that mentoring creates for novice teachers in different contexts. When designing mentoring programs and arranging mentoring relationships, teacher educators need to consider how to restructure school contexts and help mentors learn how to mentor.     

Using digital and paper diaries for learning and assessment purposes in higher education: a comparative study of feasibility and reliability

The incorporation of diaries and journals as learning and assessment vehicles into programmes of study within higher education has enabled the further growth of reflection, creative writing, critical thinking and meta‐cognitive processes of students’ learning. However, there is currently little research that aims to compare how different types of diary are used and for what specific learning and teaching purposes, so, with this in mind, a study was carried out to investigate digital diary use within a group of undergraduates, to some of whom the authors allocated Personal Digital Assistants (PDAs), which they used to contribute to a blog (digital diaries), and to some of whom hard‐backed format (paper diaries) were given. This paper is the first of two from this study. The findings indicated that whilst students found both forms of diary acceptable and convenient, differences emerged in the way that the diaries were being used on a day‐to‐day basis, both in the frequency of entry and in the length of entries made. Throughout the study, the digital diaries were used more frequently, although the entries were often brief and incomplete. Conversely, students completing the paper diaries made significantly fewer entries in total, but those that were made were longer and more discursive in nature. Further, it was found that the paper diaries possessed positive qualities related to handling and attractiveness that promoted more prolonged use, whilst the negative qualities of the digital diaries were linked to technical limitations. The implications of this work are considered in relation to more general notions of using dynamic devices to encourage students to engage in reflexive criticism.     

Using informed strategies for learning to enhance the reading and thinking skills of children with learning disabilities

The purpose of this study was to improve the reading performance of children with learning disabilities using a classroom-based metacognitive reading program. The participants were third- and fourth-level 8- and 9-year-olds (13 boys and 5 girls) at a school for children with learning disabilities. A cross-sectional time series design was used. During pre- and posttesting participants were assessed on two measures of strategy awareness and a measure of perceived self-competence. During the instructional phase the metacognitive reading program was introduced. Participants were assessed on measures of reading performance throughout the study. In general, the findings were positive: Students increased in performance and awareness of strategies from pre- to posttesting. In addition, participants were placed in subgroups based on pretesting assessments. The subgroups differed on their improvements over time. This study provides preliminary evidence that a metacognitive reading program can be used with children with learning disabilities to improve their awareness about reading and their comprehension skills.     

Effects of cooperative learning plus inquiry method on student learning and attitudes: a comparative study for engineering economic classrooms

In the Iranian higher education system, including engineering education, effective implementation of cooperative learning is difficult because classrooms are usually crowded and the students never had a formal group working background in their previous education. In order to achieve the benefits of cooperative learning in this condition, this paper proposes a combination of cooperative learning and inquiry method. The method is implemented by grouping students in a way that the learning procedure is done in non-official class sessions by each group, while the inquiry method is done in the regular programmed class sessions. The study is performed in Islamic Azad University and the methods are implemented in two engineering economic classes with different numbers of students in each working group. The results are compared with a control class in which traditional teaching style is implemented. The results of analysis show simultaneous improvement of learning and behavioural attitudes of the students with cooperative learning plus inquiry method in the classroom with a fewer number of students in each working group.     

Using formative assessment to influence self- and co-regulated learning: the role of evaluative judgement

European Journal of Psychology of Education - Recently, the concept of evaluative judgement has gained attention as a pedagogical approach to classroom formative assessment practices. Evaluative...     

Effects of online note taking formats and self-monitoring prompts on learning from online text: Using technology to enhance self-regulated learning

This study explored conditions under which note taking methods and self-monitoring prompts are most effective for facilitating information collection and achievement in an online learning enviornment. In experiment 1 30 students collected notes from a website using an online conventional, outline, or matrix note taking tool. In experiment 2 119 students collected notes from a larger, more ecologically valid set of learning materials using the conventional, outline, or the matrix tool. One half of the students also received prompts designed to encourage self-monitoring. Results of both experiments indicated that the matrix note taking device was a superior tool for collecting information and for achievement. Results of experiment 2 indicated that self-monitoring prompts have a significant positive impact on notes taken and achievement as well. Results are discussed relative to self-regulated learning and perceptual enhancement theories.     

Models of transformative learning for social justice: comparative case studies of non-formal development education in Britain and Spain

This paper presents comparative case studies of non-formal development education by non-profit organisations in two European countries. The study aimed to explore the extent to which such activities provide opportunities for transformative learning. The research was qualitative and began with interviews with educators across 14 organisations in Britain and Spain. Case studies were then identified, purposefully selecting interesting non-formal activities. This paper presents four activities and analyses their potential for transformative learning, drawing together ideas from the literature and the cross-case analysis of the perspectives of development education practitioners. By using the framework of transformative learning pedagogies, this research can inform non-formal education with aims regarding social justice in a range of contexts. It is argued that while there are scarce opportunities for sustained non-formal development education, these cases contribute to knowledge by providing examples of how participative methodologies can generate critical thinking and thus offer learning opportunities that are transformational.     

Lifelong learning and learning to learn: An enabler of new voices for the new times

Over the last two decades, there have been numerous attempts to review and re-examine whether conventional learning and teaching approaches are still useful or relevant. Lifelong learning institutions have grown in number and scope, and now fulfil a significant function in bridging the gap between what traditional formal education systems provide and what the rapidly changing labour market requires. Lifelong learning is a mode of seamless learning, whereby informal and experiential learning acquired in various settings can be converted to recognised learning, thereby helping to systematise the various learning experiences into knowledge formation, knowledge building and knowledge creation. This paper analyses certain features of the 21st century such as the knowledge economy, diversity and plurality, and equity. Communities now need to provide more opportunities for everyone to learn for their individual needs, especially when societal changes are happening at a fast pace and in an unpredictable manner. Anticipatory learning for the unknown will become a significant agenda of teaching and learning in the new times, and thus, the availability of lifelong learning opportunities will be essential for preparing citizens of the new times to meet the changing needs that confront them.     

硼砂废渣中提取MgSO4·7H2O的镁钙测定方法研究

“从硼砂废渣中提取MgSO4.7H2O”是一个综合性强、具有应用意义的实验。但在产品纯度测定中,分析方法存在缺陷。原方法要测定产品硫酸镁中的镁含量,实际得到的是钙镁总量。在经过大量研究的基础上,提出改进方法即滴定前加入EGTA掩蔽钙,用EDTA法测定镁含量,同时能准确得到钙含量。实验结果镁标样回收率在99.9%~100.1%,钙标样回收率在99.1%~101.3%。实验方法对工业分析也有一定指导意义。     

The hidden depths of new word knowledge: Using graded measures of orthographic and semantic learning to measure vocabulary acquisition

We investigated whether the presence of orthography promotes new word learning (orthographic facilitation). In Study 1 (N = 41) and Study 2 (N = 74), children were taught 16 unknown polysyllabic words. Half of the words appeared with orthography present and half without orthography. Learning assessments captured the degree of semantic and orthographic learning; they were administered one week after teaching (Studies 1 and 2), and, unusually, eight months later (Study 1 only). Bayesian analyses indicated that the presence of orthography was associated with more word learning, though this effect was estimated with more certainty for orthographic than semantic learning. Newly learned word knowledge was well retained over time, indicating that our paradigm was sufficient to support long-term learning. Our approach provides an example of how word learning studies can look beyond simple accuracy measures to reveal the cumulative nature of lexical learning.     

Using virtual microscopy to scaffold learning of pathology: a naturalistic experiment on the role of visual and conceptual cues

New representational technologies, such as virtual microscopy, create new affordances for medical education. In the article, a study on the following two issues is reported: (a) How does collaborative use of virtual microscopy shape students’ engagement with and learning from virtual slides of tissue specimen? (b) How do visual and conceptual cues scaffold students’ reasoning? Fifteen pairs of medical students participated in two sessions in which the students used a virtual microscope as a diagnostic tool in the context of learning pathology. The slides provided the students with varying levels of visual and conceptual cueing. The sessions were videotaped, and the students’ reasoning while using the microscope was analysed. The students’ written answers were analysed in terms of the findings they made and the diagnoses suggested. At a general level, the results show that students engage actively in this kind of virtually-mediated environment. The visual and/or conceptual cues improve students’ performance, and guide the students’ perception and reasoning in a manner that is productive from the point of view of learning to make clinically relevant observations. Scaffolding students’ reasoning process through cues furthermore assists the students in avoiding the most obvious pitfalls such as overlooking critical areas of a specimen. Overall, visual and conceptual cues improve students’ reasoning in perceptual and cognitive terms, while still allowing space for the making of “relevant mistakes” that may further the students’ diagnostic skills.     

Learning as Making: Using 3D computer-aided design to enhance the learning of shape and space in STEM-integrated ways

The recent and popular “Maker” movement worldwide has revived conversations about creativity, hands-on “Making,” arts and design, humans with tools and digital experiences beyond the flat-screen. However, such conversation mainly revolved outside the realm of formal education. This article presents two learning tasks, one in upper primary (age 10–11) and one in lower secondary (age 12–13), which integrate “Making” and 3D computer-aided design (CAD), thereby facilitating Science, Technology, Engineering, and Mathematics (STEM) learning in mathematics classrooms. By adopting a design-based research methodology, we examine students' mathematics learning with respect to dissecting and forming 2D shapes and volume of composite solids with the use of 3D CAD and the kinds of integrated STEM learning practices they demonstrated in the activities. Qualitative data were collected in the form of videos of the students' communication and screenshots of their initial and final designs as they engaged with the 3D CAD environment, as well as students' written reflections and teachers' lesson analysis. Results showed that the students used 3D CAD to develop spatial skills and to achieve mathematics learning far beyond using formulae and performing procedures. The learning activities also enabled an integrated STEM learning experience in productive and unobtrusive ways.     

Creating foundations for collaboration in schools: Utilizing professional learning communities to support teacher candidate learning and visions of teaching

Despite widespread acknowledgment of the power of professional collaboration, the norm in most schools is teachers working in isolation. Our study examined the impact of multiple layers of professional collaboration intentionally integrated into a one-year preservice teacher education program working in two elementary schools. Analysis of 23 teacher candidates' written reflections, focus group interviews, and classroom observations indicated that supported by collaboration with colleagues, they developed the skills and commitment to teach each student for understanding. Based on our research, we propose a shift in teacher education toward collaborative inquiry about teaching and learning within school/university partnerships.     

为学习设计教学——"比较文学"课程的网络教学设计与实践

网络教学以资源共享、时空不限、交互协作等优势为远程教学双方提供了极大的便利,然而要将这种优势和便利转化为实践,首先必须要有合理的教学设计.我们希望通过"基于网络环境的《比较文学概论》课程教学模式"的实验研究,为开展基于网络的课程教学提供个案经验.本文主要介绍了该课程的网络教学设计与实践检验结果.