Isolation and manipulation of living adherent cells by micromolded magnetic rafts

A new strategy for magnetically manipulating and isolating adherent cells with extremely high post-collection purity and viability is reported. Micromolded magnetic elements (termed microrafts) were fabricated in an array format and used as culture surfaces and carriers for living, adherent cells. A poly(styrene-co-acrylic acid) polymer containing well dispersed magnetic nanoparticles was developed for creating the microstructures by molding. Nanoparticles of γFe(2)O(3) at concentrations up to 1% wt.∕wt. could be used to fabricate microrafts that were optically transparent, highly magnetic, biocompatible, and minimally fluorescent. To prevent cellular uptake of nanoparticles from the magnetic polymer, a poly(styrene-co-acrylic acid) layer lacking γFe(2)O(3) nanoparticles was placed over the initial magnetic microraft layer to prevent cellular uptake of the γFe(2)O(3) during culture. The microraft surface geometry and physical properties were altered by varying the polymer concentration or layering different polymers during fabrication. Cells plated on the magnetic microrafts were visualized using standard imaging techniques including brightfield, epifluorescence, and confocal microscopy. Magnetic microrafts possessing cells of interest were dislodged from the array and efficiently collected with an external magnet. To demonstrate the feasibility of cell isolation using the magnetic microrafts, a mixed population of wild-type cells and cells stably transfected with a fluorescent protein was plated onto an array. Microrafts possessing single, fluorescent cells were released from the array and magnetically collected. A post-sorting single-cell cloning rate of 92% and a purity of 100% were attained.     

Enhancing children's thinking skills: an instructional model for decision-making under certainty

Modern society is characterized by rapid change, an overload of information, an interrelation between once distinct fields (science, technology and society) and a growing recognition of the importance of personal and social values. In such a dynamic society the teaching of facts becomes less vital while the teaching of thinking skills turns out to be indispensable. Educators have recognized the need for curricula devoted to thinking skills in general and attempts to attain this goal have already been made. However, almost no attention has been given to teaching children the very important and daily used skill of decision-making under certainty. In the present paper we propose a framework for developing school material which cultivates decision-making skills. This framework is a tripartite model which describes (a) the general strategy an ideal decision maker should adopt, (b) the underlying cognitive skills needed for that strategy and (c) the educational objectives for the promotion of each cognitive skill mentioned.Science in a Technological Society, a curriculum developed in the Israeli Science Teaching Center, Center for Curriculum Research and Development, School of Education, Tel-Aviv University.NoteIsraeli Science Teaching Center, Center for Curriculum Research & Development, School of Education,Tel-Aviv University     

The Development of Perspective Taking: Understanding Differences in Information and Weighting

2 separate aspects of perspective taking are that judgments attributed to another should depend on the information available to the other (Information effect) and on how the other's use of information differs from one's own (Weighting effect). These 2 aspects of perspective taking were studied in a moral judgment task with preschoolers, and second and fifth graders. Subjects were read a series of stories about a little boy transgressing and asked to make judgments from both their own perspective and that of a mother character in the stories. The mother story character had either the same information as the subject or only partial information. Valence of intention and consequence and the amount of mother's knowledge varied factorially. Subjects were clustered using scores derived from the judgements. 3 clusters were found that showed different levels of perspective-taking ability. There was a developmental progression in the 3 levels of perspective taking. Subjects in the Harshness cluster attributed harsher judgments to the mother perspective. Subjects in the Weighting cluster weighted information differently depending on the perspective from which they judged. Subjects in the Information-and-Weighting cluster weighted information differently depending on perspective, and also considered the amount of information available to the mother character in attributing judgments. The findings are compared to current theory on the development of perspective taking. Future research and theory need to consider the influence of both information and weighting differences on performance in perspective-taking tasks.     

Need for approval and children's well-being

This research examined the hypothesis that a tendency to base one's self-worth on peer approval is associated with positive and negative aspects of children's well-being. A sample of 153 fourth through eighth graders (9.0 to 14.8 years) reported on need for approval, global self-worth, social-evaluative concerns, anxiety and depression, and exposure to victimization. Teachers reported on social behavior. Results confirmed that need for approval is a two-dimensional construct composed of positive (enhanced self-worth in the face of social approval) and negative (diminished self-worth in the face of social disapproval) approval-based self-appraisals. Need for approval had trade-offs for well-being that depended on the dimension (positive vs. negative), the psychological domain (emotional vs. social adjustment), children's sex and age, and children's social context (high vs. low peer victimization).     

Professional learning and development needs of women teachers in the Republic of Pakistan: a social realist perspective

ABSTRACT

This article, emerging from a wider study on the professional development needs of women teachers working in Catholic convent schools in the Republic of Pakistan, explores the perspectives and experiences of school leaders and Principals who developed professional development programmes. This area, which has been under-researched in the professional development literature, addresses the complexities and contradictions that the glocalisation of professional development can create for women teachers in developing world contexts. A social realist approach, using Archer’s morphogenetic framework, was employed to facilitate an exploration of the varied responses that professional development needs produce. The responses of former Principals and school leaders and their efforts to provide professional development for women teachers was captured, and revealed different agential responses. These responses included an acceptance of the realities of the education system in Pakistan and the role of women in that context, a desire to follow the ethos of the Catholic religious Order which was at variance with accepted educational praxis, and the changing expectations of society within Pakistan with reference to education of children.     

Dog Treat Ball: An Activity to Introduce Systems of Differential Equations

Abstract

This paper describes an activity using a dog treat ball to introduce systems of first-order differential equations. Beads are placed in the first of two hemispherical chambers of a food-dispensing dog toy. As the ball is turned, students track the number of beads in the first chamber, the second chamber, and the exterior of the ball. Students develop a working assumption, write a system of differential equations to model the number of beads in each region, and use a spreadsheet to compare their experimental and model results.     

A synthesis of fluency interventions for secondary struggling readers

Previous research studies examining the effects of fluency interventions on the fluency and comprehension outcomes for secondary struggling readers are synthesized. An extensive search of the professional literature between 1980 and 2005 yielded a total of 19 intervention studies that provided fluency interventions to secondary struggling readers and measured comprehension and/or fluency outcomes. Findings revealed fluency outcomes were consistently improved following interventions that included listening passage previewing such as listening to an audiotape or adult model of good reading before attempting to read a passage. In addition, there is preliminary evidence that there may be no differential effects between repeated reading interventions and the same amount of non-repetitive reading with older struggling readers for increasing reading speed, word recognition, and comprehension.