Formation of embryoid bodies using dielectrophoresis

Embryoid body (EB) formation forms an important step in embryonic stem cell differentiation invivo. In murine embryonic stem cell (mESC) cultures EB formation is inhibited by the inclusion of leukaemic inhibitory factor (LIF) in the medium. Assembly of mESCs into aggregates by positive dielectrophoresis (DEP) in high field regions between interdigitated oppositely castellated electrodes was found to initiate EB formation. Embryoid body formation in aggregates formed with DEP occurred at a more rapid rate-in fact faster compared to conventional methods-in medium without LIF. However, EB formation also occurred in medium in which LIF was present when the cells were aggregated with DEP. The optimum characteristic size for the electrodes for EB formation with DEP was found to be 75-100 microns; aggregates smaller than this tended to merge, whilst aggregates larger than this tended to split to form multiple EBs. Experiments with ESCs in which green fluorescent protein (GFP) production was targeted to the mesodermal gene brachyury indicated that differentiation within embryoid bodies of this size may preferentially occur along the mesoderm lineage. As hematopoietic lineages during normal development derive from mesoderm, the finding points to a possible application of DEP formed EBs in the production of blood-based products from ESCs.     

Intervention for children with language impairments: a model of evidence-based outcome research

Over the past 30 years successive governments in the UK have endeavoured to make the statutory framework suitable for children with special educational needs (SEN). More recently, efforts have been made to personalise children's learning, making educational experience more innovative and responsive to the diversity of needs in schools. A drive is emerging in health and education to develop and evaluate intervention strategies for children with language impairments (LIs), which is both methodologically challenging and rewarding. The current review demonstrates difficulties encountered with using evidence-based (evidence-related) outcome research involving children with LIs. Many studies have inherent methodological problems such as small sample sizes, ill-matched groups and designs that are difficult to replicate or compare. Such approaches are unlikely to yield significant results, or if they do, it is difficult to devise clear guidance regarding choice of intervention strategies. In the light of these difficulties, theoretical, methodological and practical issues are discussed herein and a model is proposed to assist in enabling interventions to be identified, evaluated in a robust manner, and the results shared with educators. We suggest that the use of a process-driven model ensures a more rigorous approach when undertaking large-scale systematic, evidence-based research into the effective approaches to teaching children not only with LIs but across the field of special needs education.     

Exploring Science Teachers’ Argumentation and Personal Epistemology About Global Climate Change

Research in Science Education - This case study investigated the nature of in-service science teachers’ argumentation and personal epistemology about global climate change during a 3-year...     

How university teaching changes teachers: Affective as well as cognitive challenges

This paper argues that the teaching of a subject can change our understanding of what it means to know, to teach and learn that subject. It also argues that when our understanding is questioned and changes then academic work can become an emotionally charged endeavour. This paper reports on a study where, over a semesters teaching, around two thirds of teachers changed some aspect of their scholarly thinking or practice. These teachers were teaching a range of first and second year classes, they were not new to teaching, nor were they unfamiliar with the teaching of the subject. For approximately one third, the change in understanding was not major. It involved a change in teaching practice but it did not involve the questioning of their existing understanding of subject matter. For another third, however, the change was substantial. These teachers, in some way, questioned previously taken for granted assumptions, they re-thought aspects of the structure of the discipline or the relationship of the subject to the discipline. They also revised their ideas about how to best teach that subject and what learning the subject involved. This change invariably involved anxiety and uncertainty and in some cases this was extreme. Little attention has been paid to change in teachers understanding of subject matter and little, or no, research has focused on the emotional impact of this change. This initial exploration of these neglected aspects of university teaching suggests a rich vein for further exploration. This paper builds on previous work that has used phenomenography to examine changes in university teachers understanding of subject matter taught. An analysis of metaphor is used to explore change and to tap into the rich and complex emotional experiences that accompany this change.