Uppermost Mississippian Brachiopods from the Basal Itaituba formation of the Amazon Basin, Brazil

This paper describes 19 brachiopod species (including six indeterminate species) in 15 genera and one indeterminate genus from the basal Itaituba Formation at the Caima Quarry 1 section of Itaituba, Amazon Basin, Brazil. The faunal correlations of the brachiopods and the associated fusulinids and conodonts indicate a late Chesterian (late Serpukhovian) age for the described fauna, therefore confirming for the first time the presence of uppermost Mississippian rocks in the Amazon Basin. A new species, Composita caimaensis, is created, and two species, Inflatia cf. gracilis and Marginovatia cf. catinulus, are described for the first time from the Amazon Basin. The Amazon brachiopods appear to be of strong affinity with coeval faunas of the North American midcontinent.

Extracellular matrix induces formation of organoids and changes in cell surface morphology in cultured human breast carcinoma cells PMC42-LA

In the lactating breast, the development of secretory alveoli consisting of differentiated cells arranged around a central lumen is dependent on signals from the extracellular environment of the cells. There are few cell lines that model this process. We previously showed that the human breast carcinoma line PMC42-LA can be induced to form organoids, reminiscent of secretory alveoli found in the lactating human breast. In this report, we used high-resolution scanning electron microscopy to show that the formation of organoids is accompanied by development of cell surface microvilli. Extracellular matrix-induced formation of microvilli occurred on the internal and external surfaces of cells in the organoids and not on surfaces in contact with the extracellular matrix. Organoid formation of PMC42-LA cells induced a rearrangement of the extracellular matrix, seen in the form of radiating fibers from the organoids. In summary, there is an interaction between PMC42-LA cells and the underlying extracellular matrix, which leads to the formation of polarized cells with well-developed microvilli. This is accompanied by organization of the extracellular matrix. PMC42-LA is a relevant model of the human breast for investigations into cell-cell and cell-matrix interactions.

Clinical education : a challenging component of undergraduate nursing education

Clinical education is an essential part of every undergraduate nursing curriculum. The main benefits are that it allows students to put theory into practice and experience the realities of the practice- based nursing profession. Limitations include the unstable nature of the clinical area as a learning environment and the challenges this produces with students' assessments. This article reviews the literature and concludes there is room for significant improvement in the area of clinical education and numerous strategies can be implemented to do so.

In situ formation of BN nanotubes during nitriding reactions

High-yield multiwalled boron nitride (BN) nanotubes have been produced using a ball milling-annealing method. The BN nanotubes with a diameter less than 10 nm and a well-crystallized multiwalled structure were formed via an in situ nitriding reaction. The systematic investigation of the formation process at different annealing temperatures and for different times suggested that the formation of the unique multiwalled structure was attributed by a two-dimensional growth of the BN phase and a nonmetal catalytic growth.

Bone formation following implantation of titanium sponge rods into humeral osteotomies in dogs : a histological and histometrical study

Background: Titanium (Ti) is widely proven to enhance bone contact and growth on its surface. It is expected that bone defects could benefit from Ti to promote healing and to increase strength of the implanted area.

Purpose: The present study aimed at comparing the potential of porous Ti sponge rods with synthetic hydroxyapatite (HA) for the healing of bone defects in a canine model.

Material and Methods: Six mongrel dogs were submitted to three trephined osteotomies of 6.0 × 4.0 mm in one humerus and after 2 months another three osteotomies were performed in the contralateral humerus. A total of 36 defects were randomly filled either with Ti foam, particulate HA, or coagulum (control). The six animals were killed 4 months after the first surgery for histological and histometrical analysis.

Results: The Ti-foam surface was frequently found in intimate contact with new bone especially at the defect walls. Control sites showed higher amounts of newly formed bone at 2 months – Ti (p = 0.000) and HA (p = 0.009) – and 4 months when compared with Ti (p = 0.001). Differently from HA, the Ti foam was densely distributed across the defect area which rendered less space for bone growth in the latter's sites. The use of Ti foams or HA resulted in similar amounts of bone formation in both time intervals. Nevertheless, the presence of a Ti-foam rod preserved defect's marginal bone height as compared with control groups. Also, the Ti-foam group showed a more mature bone pattern at 4 months than HA sites.

Conclusion: The Ti foam exhibited good biocompatibility, and its application resulted in improved maintenance of bone height compared with control sites. The Ti foam in a rod design exhibited bone ingrowth properties suitable for further exploration in other experimental situations.

A descriptive model for the formation of ultrafine grained steels

This paper presents a descriptive model to explain the mechanisms involved in the development of ultrafine grained structure in steels through dynamic strain induced transformation. The model considers the microstructural evolution during and after deformation as well as the role of different process variables. A key factor is the competition between nucleation and growth, where it is shown that many potential nuclei can be lost under certain conditions leading to a mixed or coarser grain size.

Formation of ultrafine ferrite by dynamic strain-induced transformation

In the current study, the role of dynamic strain induced transformation on ferrite grain refinement was investigated using different thermomechanical processing routes. A Ni-30Fe austenitic model alloy was also employed to study the evolution of the deformation structure under different deformation conditions. It was shown that the extreme refinement of ferrite is more likely due to the formation of extensive high angle intragranular defects in the austenite through deformation. Among the different thermomechanical parameters, the deformation temperature had a significant effect on the intragranular defect characteristics. There was a transition where the cell dislocation structure changed to laminar microband structures with a decrease in the deformation temperature. Moreover, the ultrafine grained structure was also successfully produced through static transformation using warm deformation process; in other words, concurrent deformation and transformation are not necessary for ultrafine ferrite formation.

Investigating the factors of professional development programs that effect change in the classroom

This paper reports on the implementation of two professional development programs designed to support ICT based pedagogies in Victorian (Australia) schools. In both programs the teachers participated in an intensive program of professional development designed to assist them in embedding ICT into their classroom practice. There was a large diversity of circumstances experienced by the schools, not only in terms of ICT availability and use, and teacher experience, but also in issues of cultures of curriculum planning and integration, size, communication, and pedagogical presumptions. Both projects were successful in implementing change; however there were teachers in both projects who failed to take advantage of the PD. Some of the limitations with both studies include the high expectations of time comittment by the teachers – who are already fully committed with full teaching loads, and the high expectations of the change that will occur in the teaching and
learning as a result of the PD, wthout consideration of the time needed to learn and adopt new pedagogical practice. In some cases, teachers and the school did not appreciate the necessary commitment to take full advantage of the opportunity being provided. This was compounded by the lack of support and recognition by school management.

Dimerisation of N-acetyl-L-tyrosine ethyl ester and Aß peptides via formation of dityrosine

Alzheimer's disease (AD) is characterised by the formation of amyloid deposits composed primarily of the amyloid β-peptide (Aβ). This peptide has been shown to bind redox active metals ions such as copper and iron, leading to the production of reactive oxygen species (ROS) and formation of hydrogen peroxide (H2O2). The generation of H2O2 has been linked with Aβ neurotoxicity and neurodegeneration in AD. Because of the relative stability of a tyrosyl radical, the tyrosine residue (Tyr-10) is believed to be critical to the neurotoxicity of Aβ. This residue has also been shown to be important to Aβ aggregation and amyloid formation. It is possible that the formation of an Aβ tyrosyl radical leads to increased aggregation via the formation of dityrosine as an early aggregation step, which is supported by the identification of dityrosine in amyloid plaque. The role of dityrosine formation in Aβ aggregation and neurotoxicity is as yet undetermined, partly because there are no facile methods for the synthesis of Aβ dimers containing dityrosine. Here we report the use of horseradish peroxidase and H2O2 to dimerise N-acetyl-l-tyrosine ethyl ester and apply the optimised conditions for dityrosine formation to fully unprotected Aβ peptides. We also report a simple fluorescent plate reader method for monitoring Aβ dimerisation via dityrosine formation.

New teachers, professional knowledge and educational reform in New Zealand

This thesis examines the professional knowledge of new secondary school teachers in New Zealand, their negotiation of multiple discourses encountered in policy and practice, and their processes of professional identity formation. It is also a study of policy reform. In New Zealand, as elsewhere, recent educational and social reforms have brought about major changes to the way education is managed and implemented. These reforms emphasise market ideologies promoting consumer choice and responsibility, while measuring and monitoring quality and effectiveness. At the same time, the reforms attempt to alleviate social inequality. Teachers' negotiation of an accountability culture and the dominant equity policies is a major focus of this study. The study draws upon group interviews held with nine new teachers during the first two years of their teaching careers. The group interviews were designed to elicit extended narratives from individual teachers, as well as promote more interactive dialogue and reflections within the groups. Because the interviews were conducted at different points in their early careers, the study also has a longitudinal element, allowing insight into how teachers' views are formed or changed during an intense period of professional learning. Analysis of the teachers' narratives is informed by poststructural and feminist understandings of identity and knowledge and by a methodological orientation to writing as a method of enquiry. The thesis develops three main types of discussion and sets of arguments. The first examines new teachers' negotiation of the 'macro' context of teacher knowledge formation that is, their negotiation of an educational policy environment that juxtaposes an equity agenda with accountability controls. In order to historically situate these dilemmas, the particular political, social and educational context of New Zealand is examined. It is argued that teachers negotiate competing political and conceptual debates about social justice, equity and difference, and that this negotiation is central to the formation of professional knowledge. The analysis illustrates ways in which teachers make sense of equity discourses in educational policy and practice, and the apparent contradictions that arise from placing tight accountability standards on schools and teachers to achieve associated equity goals. The second type of discussion focuses on teachers' negotiation of the 'micro' dimension of professional knowledge, looking closely at the processes and practices that form professional identity. Against stage or developmental models of teacher identity, it is argued that professional identity is formed in an ongoing, uneven and fluid manner and is socially and discursively situated/embedded. It is further argued that professional knowledge and identity are entwined and that this relationship is most usefully understood through analysis of the discursive practices that frame teachers' working lives and through which teachers work out who they are or should become and what and how they (should) think. This analysis contributes new perspectives to debates in teacher education about teacher preparation and the knowledge required of teachers in current 'new times'. The final cluster of arguments brings together these macro and micro aspects of professional knowledge and identity with a case study of how new teachers negotiated a recent educational reform of senior secondary school qualifications in New Zealand. This reform has had a significant impact on secondary schools and on the way teachers, and New Zealanders in general, think about education, achievement and success. It was found that this reform significantly challenged new teachers to question their beliefs about assessment and justice in education, and what counts as success. This case study draws attention to the tensions between equity, academic excellence and standards-based assessment, and contributes to understanding how teacher professional knowledge forms both in the context of a specific educational policy reform and in relation to educational reform in general. This study contributes new knowledge to the formation of teacher professional knowledge and identity in an educational climate of change in New Zealand. The findings offer new insights for teacher educators, policymakers and schools into how teachers build, shape and sustain professional knowledge; how they juggle contradictions between a desire for justice, policy imperatives and teacher education rhetoric; the self-constructed, but contingent nature of professional knowledge and identity; and the urgency to address identity formation as part of teacher education and to take account of the dynamic ways in which identities form. These matters need to be articulated in teacher education both pre-service and in-service in order to address teacher retention and satisfaction, and teachers' commitment to equity reform in education.