Diverse fibrillar peptides directly bind the Alzheimer’s amyloid precursor protein and amyloid precursor-like protein 2 resulting in cellular accumulation

The Alzheimer’s disease Aβ peptide can increase the levels of cell-associated amyloid precursor protein (APP) in vitro. To determine the specificity of this response for Aβ and whether it is related to cytotoxicity, we tested a diverse range of fibrillar peptides including amyloid-β (Aβ), the fibrillar prion peptides PrP106–126 and PrP178–193 and human islet-cell amylin. All these peptides increased the levels of APP and amyloid precursor-like protein 2 (APLP2) in primary cultures of astrocytes and neurons. Specificity was shown by a lack of change to amyloid precursor-like protein 1, τ-1 and cellular prion protein (PrPc) levels. APP and APLP2 levels were elevated only in cultures exposed to fibrillar peptides as assessed by electron microscopy and not in cultures treated with non-fibrillogenic peptide variants or aggregated lipoprotein. We found that PrP106–126 and the non-toxic but fibril-forming PrP178–193 increased APP levels in cultures derived from both wild-type and PrPc-deficient mice indicating that fibrillar peptides up-regulate APP through a non-cytotoxic mechanism and irrespective of parental protein expression. Fibrillar PrP106–126 and Aβ peptides bound recombinant APP and APLP2 suggesting the accumulation of these proteins was mediated by direct binding to the fibrillated peptide. This was supported by decreased APP accumulation following extensive washing of the cultures to remove fibrillar aggregates. Pre-incubation of fibrillar peptide with recombinant APP18–146, the putative fibril binding site, also abrogated the accumulation of APP. These findings show that diverse fibrillogenic peptides can induce accumulation of APP and APLP2 and this mechanism could contribute to pathogenesis in neurodegenerative disorders.r />

Does student engagement in self-assessment calibrate their judgement over time?

One of the implicit aims of higher education is to enable students to become better judges of their own work. This paper examines whether students who voluntarily engage in self-assessment improve in their capacity to make those judgements. The study utilises data from a web-based marking system that provides students with the opportunity to assess themselves on each criterion for each assessment task throughout a programme of study. Student marks were compared with those from tutors to plot changes over time. The findings suggest that overall students’ judgements do converge with those of tutors, but that there is considerable variation across achievement levels, with weaker students showing little improvement. Whilst the study is limited by the exigencies of voluntary participation and thus consequential gaps in the data set, it shows how judgement over time can be demonstrated and points to the potential for more systematic interventions to improve students’ judgements. It also illustrates the use of the web-based marking and feedback software (ReView) that has considerable utility in aiding self-assessment research.

The calibration of student judgement through self-assessment: disruptive effects of assessment patterns

Can extended opportunities for self-assessment over time help students develop the capacity to make better judgements about their work? Using evidence gathered through students' voluntary self-assessment of their performance with respect to assessment tasks in two different disciplines at two Australian universities, the paper focuses on the effects of sequences of units of study and the use of different types of assessment task (written, oral, analysis, and project) in the development of student judgement. Convergence between student criteria-based gradings of their own performance in units of study and those allocated by tutors was analysed to explore the calibration of students' judgement over time. First, it seeks to replicate analyses from an earlier smaller-scale study to confirm that students' judgements can be calibrated through continuing opportunities for self-assessment and feedback. Second, it extends the analysis to coherently designed sequences of units of study and explores the effects of different types of assessment. It finds that disruptive patterns of assessment within a sequence of subjects can reduce convergence between student and tutor judgements.

Balancing the environmental benefits of reforestation in agricultural regions

Reforestation is an important tool for reducing or reversing biodiversity loss and mitigating climate change. However, there are many potential compromises between the structural (biodiversity) and functional (carbon sequestration and water yield) effects of reforestation, which can be affected by decisions on spatial design and establishment of plantings. We review the environmental responses to reforestation and show that manipulating the configuration of plantings (location, size, species mix and tree density) increases a range of environmental benefits. More extensive tree plantings (>10. ha) provide more habitat, and greater improvements to carbon and water cycling. Planting a mixture of native trees and shrubs is best for biodiversity, while traditional plantation species, generally non-native species, sequester C faster. Tree density can be manipulated at planting or during early development to accelerate structural maturity and to manage water yields. A diversity of habitats will be created by planting in a variety of landscape positions and by emulating the patchy distribution of forest types, which characterized many regions prior to extensive landscape transformation. Areas with shallow aquifers can be planted to reduce water pollution or avoided to maintain water yields. Reforestation should be used to build forest networks that are surrounded by low-intensity land use and that provide links within regions and between biomes. While there are adequate models for C sequestration and changes in water yields after reforestation, the quantitative understanding of changes in habitat resources and species composition is more limited. Development of spatial and temporal modelling platforms based on empirical models of structural and functional outcomes of reforestation is essential for deciding how to reconfigure agricultural regions. To build such platforms, we must quantify: (a) the influence of previous land uses, establishment methods, species mixes and interactions with adjacent land uses on environmental (particularly biodiversity) outcomes of reforestation and (b) the ways in which responses measured at the level of individual plantings scale up to watersheds and regions. Models based on this information will help widespread reforestation for carbon sequestration to improve native biodiversity, nutrient cycling and water balance at regional scales.

P F Thompson - Australia's pioneer in corrosion research and education

Percival Faraday Thompson (P F Thompson, PFT), (1885-1951),(Figure1), a metallurgistand chemical analyst, is widely considered as Australia’s pioneer in corrosion science and education. Each year at the annual ACA Conference, the P F Thompson Memorial Lectureis presented by a person who has made a most significant contribution to corrosion science and engineering in Australia. While each presenter usually gives a few detailsof the work of PFT for the benefit of Conference attendees, the entire body of his work and details about his life are not provided due to the limitations on the lecture duration. A review of Thompson’s life and some of his work is available in the ‘Australasian Corrosion Engineering’ publication which was the ACA publication in the early 70s, and is one of theprecursors to the current ACA publication Corrosion & Materials (Potter, 1972). However this publication is not widely available to the ACA membership, and certainly not inelectronic format. The purpose of this paper is to provide readers with some of the history of the PFT Lecture, and to acquaint readers of ‘Corrosion & Materials’ and the broader corrosion prevention community with the breadth of the scientific work of PFT and his enthusiasm for describing corrosion science through practical public demonstrations ofexperiments of the basic principles of corrosion.