Copper-dependent iron assimilation pathway in the model photosynthetic eukaryote chlamydomonas reinhardtii

The unicellular green alga Chlamydomonas reinhardtii is a valuable model for studying metal metabolism in a photosynthetic background. A search of the Chlamydomonas expressed sequence tag database led to the identification of several components that form a copper-dependent iron assimilation pathway related to the high-affinity iron uptake pathway defined originally for Saccharomyces cerevisiae. They include a multicopper ferroxidase (encoded by Fox1), an iron permease (encoded by Ftr1), a copper chaperone (encoded by Atx1), and a copper-transporting ATPase. A cDNA, Fer1, encoding ferritin for iron storage also was identified. Expression analysis demonstrated that Fox1 and Ftr1 were coordinately induced by iron deficiency, as were Atx1 and Fer1, although to lesser extents. In addition, Fox1 abundance was regulated at the posttranscriptional level by copper availability. Each component exhibited sequence relationship with its yeast, mammalian, or plant counterparts to various degrees; Atx1 of C. reinhardtii is also functionally related with respect to copper chaperone and antioxidant activities. Fox1 is most highly related to the mammalian homologues hephaestin and ceruloplasmin; its occurrence and pattern of expression in Chlamydomonas indicate, for the first time, a role for copper in iron assimilation in a photosynthetic species. Nevertheless, growth of C. reinhardtii under copper- and iron-limiting conditions showed that, unlike the situation in yeast and mammals, where copper deficiency results in a secondary iron deficiency, copper-deficient Chlamydomonas cells do not exhibit symptoms of iron deficiency. We propose the existence of a copper-independent iron assimilation pathway in this organism.

Training packages and the AQTF: freedom to move or components of a compliance-driven straightjacket?

This paper reports on a PhD research project being undertaken through the Faculty of Education, Deakin University. Training Packages and the Australian Quality Training Framework (AQTF) form part of the ruling relations of VET, but how do they operate in practice? Do they provide frameworks within which training professionals are free to use judgement and respond in innovative ways to local learning and assessment contexts? Do they impose rigid 'guidelines' within which the decision-making authority of practitioners over appropriate practices is displaced by that of auditors, constraining creativity and creating pressures towards conformity? Or does their impact vary, depending on how they are interpreted and who is doing the interpreting? My PhD research explores issues relating to the use of Training Packages in workbased learning. Interview data suggests that, in practice, different training organisations respond very differently to a regulatory framework that aims to achieve national consistency. Some practitioners describe working in a compliance-driven environment, in which their ability to meet the needs of learners is stifled by standardised training and assessment practices imposed by Training Packages and the AQTF. This view is reflected in phrases such as 'you're not allowed to…', and 'you always feel uneasy because you've got AQTF compliance, inspections, auditors'. In contrast, other practitioners talk about having freedom to design learning and assessment programs for their particular target group and context, providing they stay within broad guidelines that guarantee national recognition of qualifications they issue. This view is reflected in comments such as 'it just leaves it open … to be as creative and flexible as you like', and 'It just gives us freedom'. This paper explores the proposition that the impact of these abstract and generalised texts is influenced by local interpretations, and it considers the role that organisational culture plays in determining these interpretations.

An exploration of the components of relational bonds to an arts festival brand

This research investigates the nature of the bonds that consumers form with a brand that provides highly uncertain outcomes, and is only available intermittently. The research model draws upon elements of Keller’s (2001) conceptualisation of brand resonance, and extends McAlexander, Kim, and Roberts’ (2003), and Muniz and O’Guinn’s (2001) brand community construct, testing these in an atypical service environment. Qualitative research suggested the need for a broader view of the bond formed in these circumstances, specifically one comprising measures of anticipation of usage, social attraction, commitment, loyalty, and trust. This paper reports on analysis undertaken to develop such a construct, which has been labelled “brand affinity”. Tests for discriminant validity suggest that the brand affinity construct is a distinct construct that can be used to measure consumer attitudes toward a highly uncertain, intermittently available product.

Growth performance, feed efficiency and fatty acid composition of juvenile Murray cod, Maccullochella peelii peelii, fed graded levels of canola and linseed oil

n two independent experiments, the effects of dietary inclusion of canola and linseed oil were evaluated in juvenile Murray cod (Maccullochella peelii peelii, Mitchell) over a 112-day period. In each experiment, fish received one of five semi-purified diets in which the dietary fish oil was replaced with canola oil (Experiment A) or linseed oil (Experiment B) in graded increments of 25% (0–100%). Murray cod receiving the graded canola and linseed oil diets ranged in final weight from 112.7 ± 7.6 to 73.8 ± 9.9 g and 93.9 ± 3.6 to 74.6 ± 2.2 g, respectively, and exhibited a negative trend in growth as the inclusion level increased. The fatty acid composition of the fillet and liver were modified extensively to reflect the fatty acid composition of the respective diets. Levels of oleic acid (18:1 n-9) and linoleic acid (18:2 n-6) increased with each level of canola oil inclusion while levels of α-linolenic acid (18:3 n-3) increased with each level of linseed oil inclusion. The concentration of n-3 highly unsaturated fatty acids in the fillet and liver decreased as the amount of vegetable oil in the diets increased. It is shown that the replacement of fish oil with vegetable oils in low fish meal diets for Murray cod is possible to a limited extent. Moreover, this study reaffirms the suggestion for the need to conduct ingredient substitution studies for longer periods and where possible to base the conclusions on regression analysis in addition to anova.

Photosynthesis of hydrogen and methane as key components for clean energy system

While researchers are trying to solve the world's energy woes, hydrogen is becoming the key component in sustainable energy systems. Hydrogen could be produced through photocatalytic water-splitting technology. It has also been found that hydrogen and methane could be produced through photocatalytic reduction of carbon dioxide with water. In this exploratory study, instead of coating catalysts on a substrate, pellet form of catalyst, which has better adsorption capacity, was used in the photo-reduction of carbon dioxide with water. In the experiment, some water was first absorbed into titanium dioxide pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing these wet pellets, which were then illuminated continuously using UVC lamps. Gaseous samples accumulated in the reactor were extracted at different intervals to analyze the product yields. The results confirmed that methane and hydrogen were photosynthesized using pellet form of TiO₂ catalysts. Hydrogen was formed at a rate as high as 0.16 micromoles per hour (μmol h⁻¹). The maximum formation rate of CH₄ was achieved at 0.25 μmol h⁻¹ after 24 h of irradiation. CO was also detected.

Finite element simulation of deformation processes of micro-components

The aim of this paper is to improve the understanding of deformation of micro medical needle and thread during assembly and then to develop an economical and flexible deformation method. Therefore, the swaging process is computationally simulated with the finite element method in this paper. A commercially available explicit nonlinear finite element analysis code, LS-Dyna, is used to model the 3-D deformation and contact problem. As the firmness of the assembly on the needle depends on the contact force and friction, the contact and the slide between the needle and thread are taken into account in the simulation. The general surface-to-surface contact algorithm (STS) is used to simulate the contact. The paper provides an insight into the deformation of the micro products.

Sustainable components of leadership effectiveness in organizational performance

Purpose – The objective is to describe a selection of sustainability components of leadership effectiveness in organizational performance.
Design/methodology/approach – The paper is based on a conceptual discussion. Findings – The paper contributes to descriptive models that address sustainability components of leadership effectiveness in organizational performance. The study highlights some common views that exist in the management literature and in prosperous management practice related to the direct impact of the relationship in organizational performance between leadership and effectiveness. In fact, it also highlights the critical or sceptical views of leadership effectiveness in organizational performance raised in the literature. Research limitations/implications – The paper contends that the actual leadership effectiveness in organizational performance varies over time and across contexts. At times, the achievement in organizational performance is the outcome of prosperous and conscious leadership, while it at other times may be the outcome of poor and deficient leadership. The topic at hand is positioned and limited to the interface that may describe and explain the connection between these two views. Furthermore, it is limited to corporate decision making and business behaviour in relation to leadership effectiveness and organizational performance. Practical implications – The leadership of an organization need not only to be successful today, but they also need to be successful tomorrow to stay in control and to flourish. Quality control and quality assurance are no longer enough for most organizations. They need to build an awareness of the sustainability components into processes of their management and business practices (i.e. internal and external ones) in order to be judged as successful in corporate decision-making and business behaviour in organizational performance in the long term. Originality/value – The principal contributions of the study are a model of timely leadership effectiveness, a model of contextual leadership effectiveness, and a typology of leadership effectiveness in corporate decision-making and business behaviour. These contributions provide theoretical and managerial ideas and insights into the sustainability components of leadership effectiveness in organizational performance.

Understanding the Components in Social Behavioural Change: Implications for Non-profit Organisations

In this paper we investigate the relationship between intrinsic motivation, extrinsic motivation and government influence with the over riding objective of developing more effective and efficient social behavioural change programs that have been instigated by public sector environmental management organisations. Based on the notion of intrinsic and extrinsic motivation, which has previously been shown to explain altitudes and behaviour associated with environmental issues, we extend the analysis in this paper to include the influence of government. A survey of a random sample of 566 landmanagers in South-eastern Australia was conducted and the data collected subsequently analysed using a structural equation modelling approach. The model that was developed identified the relationship between intrinsic motivation, extrinsic motivation and government influence.

Experimental investigation and finite element analysis for the study of residual stresses in roller burnished components

Burnishing is a surface modification process, which involves plastic deformation of the material at the surface of the component due to the application a highly polished and hard roller, under pressure. This results in the improvement of the surface finish of the component and induces residual compressive stresses on the surface of the component. The present work deals with the optimization of the burnishing force for the best surface finish, at constant speed and feed, for Aluminium and Mild steel workpieces. A 3dimensional finite element model is proposed for the simulation of the burnishing process, and the analysis is carried out at the optimum force determined experimentally. The induced compressive stress in the components is determined from the finite element analysis and this value is then compared with the results obtained from X-ray diffraction technique.

Prediction of residual stresses in roller burnished components : a finite element approach

Surface finish is an important factor in creating the durable metal components, and fatigue strength can be improved if compressive residual stresses are produced in the surface. Burnishing is a finishing process and compressive residual stresses are induced during the process. The present study of minimizing the surface roughness based on the experimental work, and finite element model was developed to evaluate the analytical results. Commercial purity Mild Steel and Aluminium were selected as work specimens and a high carbon high chromium roller was used as a tool for the burnishing process.