1,813 results for ResearchSpace@Auckland, 2014

  • Peripheral mitochondrial function in multiple organ dysfunction syndrome

    Chakraborty, Mandira (2014)

    Doctoral thesis
    The University of Auckland Library

    Multiple organ dysfunction syndrome (MODS) is the predominant cause of death in intensive care units worldwide but treatment remains supportive. Although mitochondrial dysfunction is thought to occur in sepsis related MODS, mitochondrial function in MODS remains poorly understood. An important barrier has been the requirement for organ biopsies to measure mitochondrial function because performing organ biopsies in patients with MODS poses significant risk of fatal bleeding and infection. A peripheral marker of mitochondrial function was therefore required. The hypotheses were that mitochondrial function can be measured from peripheral blood mononuclear cells, changes through the disease course and reflects disease severity in MODS. The aims were to develop an assay of mitochondrial function from peripheral blood and to apply it in patients in MODS through their disease course. Mitochondrial respiration assay was developed in the laboratory using peripheral blood from healthy volunteers and healthy male Wistar rats. The assay was used in experimental models of hypertension and mild acute pancreatitis and in a clinical trial of mild acute pancreatitis. Finally, peripheral blood mitochondrial function was measured daily during the first week, at three weeks and at six months in patients with MODS. Mitochondrial function from peripheral blood changed over the course of disease in MODS. Mitochondrial reactive oxygen species increased early and was followed by a decrease in mitochondrial respiration in MODS. Temporal mitochondrial respiration negatively correlated with temporal organ failure scores and mitochondrial respiration did not discriminate between septic and non septic causes of MODS. Mitochondrial respiration and mitochondrial superoxide correlated with each other throughout the first week. There were persistent features of mitochondrial dysfunction in septic MODS at six months. Multiple aspects of mitochondrial dysfunction occurred in patients with MODS and correlated with the severity of MODS. The results imply that shutting down mitochondrial respiration may be an adaptive response in MODS and manipulating mitochondrial respiration in MODS may be beneficial. The results from testing the assay in other disease states enabled a broader understanding of mitochondrial function in MODS. These findings have opened up several avenues for further clinical and laboratory research.

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  • Transport Capacity Improvement in and around Ports: A Perspective on the Empty-container-truck Trips Problem

    Islam, Md (2014)

    Doctoral thesis
    The University of Auckland Library

    The problem of capacity shortage is an important issue for the major ports of the world. In particular, there is an increased necessity for additional transport capacity for containerised goods travelling to and from the hinterland (the region served by the port). For such travel, transportation using roads is often more popular than other methods (e.g., rail). A potential mechanism to increase road-side transport capacity is to lessen the number of empty truck trips by transferring increased numbers of containers using the same number of trucks. This forms the key Research Question (RQ) for this thesis. Namely, how can the number of empty container truck trips to and from a port be reduced to increase the road transport capacity? To date, much of the existing literature on the empty trips issue has been largely of an analytical nature (e.g., the backhaul problem) and thus has generally disregarded the potential benefits of the idea of involving all of the parties concerned in the container transport chain. To bridge that research gap, this thesis extends the shared-transportation concept, which is already proving popular in other areas (car-sharing and bike-sharing systems, for example), to the maritime logistics domain, in the form of truck-sharing. For this reason, the overall thesis work involves a combination of different research methodologies, which may be either qualitative (e.g., exploratory) or quantitative (e.g., simulation). However, before diving into the specifics of empty truck trips, the thesis looks broadly at capacity shortages at ports and particularly at how can a port's capacity be improved? Therefore, a system-dynamics framework is produced based on a review of the factors influencing port capacity, to guide and improve overall port capacity (including, but not limited to, transport capacity). The thesis also shows the potential usefulness of the suggested framework as an operational tool for capacity-expansion decisions (e.g., transport capacity improvement). In support of the question of reducing empty container truck trips, the thesis has four supporting research questions. First, RQ1 is: What are the different mechanisms available in different disciplines and domains for reducing empty truck trips? One of the key findings for this question is the prospect of using the truck-sharing concept for container transportation. RQ2 is: Is it possible to introduce a dynamic truck-sharing facility for a computer-based matching system to reduce empty truck trips? This research question further applies and extends the truck-sharing concept. Therefore, the model developed to answer this question is referred to as a Truck-sharing Service (TSS). However, the successful implementation of the suggested truck-sharing model depends on truck-sharing constraints that have not been fully explored. Therefore, RQ3 is: What are the truck-sharing challenges in achieving a higher level of collaboration among carriers to gain optimal container-truck utilisation and how to best overcome those challenges? Research findings show that port-related attributes, such as a lack of flexibility in the truck appointment system, form constraints against truck-sharing. Finally, to quantify the effect of the truck-sharing model on the potential for the improvement of transport capacity and its related carbon emission saving possibilities, RQ4 is: How will the case study port???s transport capacity be affected by different scenarios? Simulation results show improvement in performance using the truck-sharing idea. In particular, the truck-sharing concept boosts port gate- and transport-capacity, handles the increasing future truck volume effectively, and decreases carbon emissions generated from container trucks. The findings of this thesis work have important implications for the study of both freight transportation and maritime logistics in the reduction of the number of empty trips made by container trucks; this thesis provides theoretical grounds for practical ways of understanding and reforming the containerised cargo transportation process for road carriers. The aim is to increasing freight transport capacity and achieving sustainable transportation benefits at the port.

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  • AGEing Peptides: Synthesis and Analysis of Peptides Site-Specifically Modified by Advanced Glycation Endproducts

    Kamalov, Meder (2014)

    Doctoral thesis
    The University of Auckland Library

    Advanced Glycation Endproducts (AGEs) are a family of modified amino acids that form when proteins react with sugars and sugar degradation products. AGEs are commonly found in processed food as well as in human organs, where they accumulate in tissue proteins, such as collagen, during the normal process of ageing. AGE accumulation dramatically accelerates with the onset of diabetes mellitus and the associated hyperglycaemia, a condition in which levels of sugars and sugar degradation product are above those considered healthy. Relative quantities of AGEs in different organs correlate with the pathophysiologic changes in these organs that occur with both advanced age and long-term hyperglycaemia. Emerging evidence indicates that AGE levels not only correlate with organ damage but may also play a causative role in such damage. Increased chelation of copper ions appears to play an important role in this process. However, the precise impact of AGE formation and accumulation on the biochemical properties of the host proteins is yet to be determined. Given their possible role in the detrimental outcomes of ageing (discussed in Chapter 1), in-depth studies of the AGE biochemistry are necessary. The overall aim of this work was to enable such in-depth studies of the AGE biochemistry by providing access to synthetic peptides that can be site-specifically modified by particular AGEs. Five prominent lysyl AGEs, N??-carboxymethyllysine (CML), N??-carboxyethyllysine (CEL), pyrraline, glyoxal lysine dimer (GOLD), and methylglyoxal lysine dimer (MOLD), were selected as targets. Synthesis of AGE building blocks, suitably protected for peptide incorporation, is discussed in Chapter 2. Efficient synthetic strategies were developed to provide access to all five AGE building blocks N??-protected by 9-Fluorenylmethoxycarbonyl (Fmoc) group. Synthesis of Fmoc-CML and Fmoc-CEL was accomplished using a facile and practical approach that involved the Fukuyama amino alkylation methodology. Fmoc-pyrraline was synthesised using an efficient pyrrole introduction protocol. Cross-linked building blocks, Fmoc2GOLD and Fmoc2MOLD, were prepared in the Debus-type amino-cyclisation procedure. Incorporation of the AGE building blocks into peptides is discussed in Chapter 2. Collagen, since it is a major target of glycation, was used as a source of synthetic peptides. By use of solid phase peptide synthesis, peptides mimicking the quaternary structures of collagen were prepared with and without AGEs. Incorporation of the CML, CEL, and pyrraline building blocks into collagen model peptides and collagen telopeptides was successfully carried out using Fmoc solid phase peptide synthesis protocol. A straightforward and cost-effective synthetic procedure to access CML-containing peptides via on-resin N-alkylation of lysyl amines has also been developed. Importantly, conditions for efficient incorporation of the lysyl AGE cross-links, GOLD and MOLD, have been successfully developed and employed in the first syntheses of crosslinked collagen model peptides and collagen telopeptides. Access to site-specifically glycated peptides has enabled us to probe the biochemical properties of glycated peptides (discussed in Chapter 4). Circular dichroism revealed that the introduction of monolysyl AGEs did not hamper the formation of triple helices by collagen model peptides. However, introduction of cross-linking AGEs effectively prevented the collagen model peptides from forming the triple helical structure. Studies of proteolytic digestion using trypsin have revealed the dramatic effect that introduction of lysyl AGEs had on the relative enzymatic digestion rates of the host peptides. These AGEs effectively prevented trypsin from digesting the host telopeptides. Our potentiometric study of copper binding by collagen telopeptides with and without CML has shown that introduction of CML dramatically increased the host peptides capacity to bind copper. Mass spectrometric analysis effectively confirmed the results of potentiometric measurements and provided the first direct evidence of increased copper binding by an AGE-modified peptide.

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  • Tools for Neuroscience: Developing Devices to Study Brain Injury and Disease

    Jowers, Casey (2014)

    Doctoral thesis
    The University of Auckland Library

    Traumatic Brain Injury (TBI) is increasingly becoming one of the major causes of death and disability in the world, and yet, no successful treatments exist for humans. To develop better drug therapies for TBI there is a need for closely controlled trauma delivery to cultured human brain cells such as astrocytes, neurons, and meningeal fibroblasts. This thesis aims to generate novel devices to provide neuroscience researchers with automated, high-throughput injury models that are both standardized and physiologically relevant. The work to follow outlines the design, characterization, and experimental testing of two devices for TBI research. In Part I, a novel, automated system for delivering controlled scratch-induced trauma to brain cells cultured in multi-well plates is created and characterized. The system is equipped with high-throughput imaging and analysis capabilities, enabling quantitative measurements of cell migration for an improved Scratch Wound Assay. The system also provides more consistent patterns of scratch-induced trauma to cultured cells when compared to traditional methods and is an effective platform for quantifying the injury response of cells. The device has applications in testing the effectiveness of drugs on cell migration and proliferation which might potentially treat traumatic brain injury. Blast-induced Traumatic Brain Injury (bTBI), a specific type of mechanical brain injury, is rapidly gathering attention due to the recent conflicts in the Middle East and the increasing prevalence of bTBI in battlefield injuries. In fact, blast injuries now make up the majority of injuries reported by US military personnel. No treatment has proven successful for bTBI and there is limited knowledge on this specific type of brain injury. To advance bTBI knowledge and develop treatments there is also a need for novel injury-producing devices. A novel injury model was created and characterized in Part II of this thesis to provide a controlled and standardized trauma, which mimics the injury mechanism of bTBI, to human brain cell cultures.

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  • The Evolution of the Japanese Strategic Imagination and Generation Change: A Generationally-Focused Analysis of Public and Elite Attitudes towards War and Peace in Japan

    Wallace, Corey (2014)

    Doctoral thesis
    The University of Auckland Library

    A significant post-Cold War development in Japan???s politics has been the rise of a group of hawkish security elites with substantial political and institutional influence. A common scholarly and popular narrative that has accompanied this development is that the younger generation in Japan is more open to the pursuit of security on the basis of realpolitik attitudes in particular, and that this will lead to the Japanese government abandoning its postwar antimilitarist security orientation. By systematically examining these claims, this study evaluates whether generational change will become a salient factor that will challenge Japan???s traditional antimilitarism and drive radical change in Japan???s security policy orientation. Members of the Heisei social generation, born between 1965 and 1989, are the core focus of this study. Members of this Heisei cohort witnessed significant change in Japan???s foreign and domestic policy environments during their formative years when political socialisation is likely to have the greatest impact upon attitude formation. Using the concept of militant internationalismas an analytical framework, this study evaluates quantitative data on public attitudes and primary interview data to identify any notable overlap in attitudes towards national security between the Heisei cohort and Japan???s hawkish security elites. This study rejects the militant internationalist characterisation by showing that the Heisei public cohort continues to support military restraints on Japan???s security policy and military posture. The analysis of attitudes does reveal, nevertheless, that antimilitarism is no longer an appropriate descriptive label to apply to the contemporary security identity embraced by the Heisei cohort. The assumption of Japanese having an instinctive aversion to the use of military tools for maintaining Japan???s security no longer holds, particularly in relation to the Heisei elite cohort. In deepening the analysis, this study does show, however, that a distinctive but evolved anti-war peace nation identity is still salient among both the Heisei public and elite cohorts. Such an identity will continue to play a notable role in restraining Japan???s evolution as a military actor in regional and global affairs, particularly in regards to Japan being able to use force inside the territory of other nations.

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  • Practice Variation and Individual Agency: CEO Compensation and the Choice between Isomorphic vis??- vis Nonisomorphic Strategies

    Benischke, Mirko (2014)

    Doctoral thesis
    The University of Auckland Library

    Although neoinstitutional theory has been increasingly used to explain a firm???s strategic choices, there is a paucity of research explaining firm heterogeneity in the adoption of strategies. Drawing on the behavioral agency model (BAM), this study argues that when managerial agents such as Chief Executive Officers (CEOs) are confronted with a tension between legitimacy risk ??? associated with non-conformance to institutional practices ??? and business risk, they will weigh the possibility of losses to their reputation and personal wealth associated with the downsides of both forms of risk. Thus, this study combines the arguments of neoinstitutional perspective arguing that managers will seek legitimacy through their choices on behalf of the firm and behavioral agency suggesting that managers are motivated by the need to limit losses of their reputation and personal wealth. The empirical framework is tested by examining 4,125 cross-border alliances and acquisitions that have been conducted by multinational corporations (MNCs) headquartered in the US in the period 1993-2010. Consistent with the theoretical framework put forward in this study, the results suggest that CEOs are less likely to reduce legitimacy risks by adopting cross-border acquisitions in response to institutional pressures when the CEO has higher levels of risk bearing, defined as wealth-at-risk of loss, in the form of stock options and cash compensation. These findings have important implications for neoinstitutional theory. In particular, the results of this study challenge the longstanding neoinstitutional assumption that firms ??? and their CEOs ??? are willing to select isomorphic strategies if reduction in firm legitimacy risk compensates for any increase in business risk. That prevailing logic implies that CEOs make strategic choices without regard to their personal risk preferences. Instead, this study has shown that the CEO is cognizant of the threat posed to their accumulated firm-specific wealth by these two dimensions of firm risk ??? i.e., legitimacy and business risk ??? and will therefore actively manage the tension between the two. Moreover, these findings also provide an alternative explanation for heterogeneity in firm strategies within organizational fields. Specifically, the results reported in this study suggest that the interplay between institutional pressures and the CEO???s risk bearing explains strategic choices and firm heterogeneity within organizational fields.

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  • Malory, Loss and Faith

    Forsberg, Andrew (2014)

    Doctoral thesis
    The University of Auckland Library

    This thesis addresses the narrative world, value systems, and narrative structures of Sir Thomas Malory???s Le Morte Darthur. I read these more literally than criticism has generally been inclined to do, and I arrive at the conclusion that the work, while complex, is remarkably consistent internally. Further, I argue the work is consistent while accurately representing in its narrative world issues for two most divergent strains of contemporary theoretical discourse on human conduct: Rene?? Girard???s work on mimesis and sacrificial logic, complemented by Michel Serres???s works on the same; and Gilles Deleuze???s reading of Friedrich Nietzsche???s oeuvre for systems of evaluating worth. The introduction begins with a brief summary of Malory???s scholarly criticism and positions itself within that critical context before providing an outline of the thesis proper and the theoretical works employed there. The remainder of the thesis is split into two parts. The first, in three chapters, unpacks the text for a cosmology, an axiology, and then a narratology. The second explores how the problems inherent in the fictional world thus composed are treated, by addressing in turn how Malory???s episodic narrative configures its beginnings, endings, and middles. I argue that in this fictional realm???s foundations, Malory???s use of Fate as a numinous agent functions as the sacred does for Girard in myth: by attempting to hide the scapegoat victim of collective murder. However, contingent and localized details intrude in Malory???s narrative to reveal that murder, and yet they do not, indeed cannot, prevent it. Further, the repetitive episodic narrative is structured in sequences that resonate with themes of desire, rivalry, and envy. These ideas are central to Girard???s mimetic hypotheses regarding the violent rituals, culture, and institutions that result from a founding sacrifice. Repetition highlights both the interminable nature of this violence, and the intrusive nature of the contingent, wherever someone is blamed. Counter to the tensions of the mythic narrative and the historical (contingent) narrative is the third term of a noble will. In accord with Deleuze???s criteria, this will is active and affirmative in Malory. It plays an increasingly prominent role in this thesis???s second part, where the focus shifts from examining narrative systems to modes; that is, to the way the narrative is told. In the time of reading, whether beginning, ending, or in a repetitive loop, the quality of a character???s will is manifest in the moment. In the best of Malory???s knights, as in Nietzsche???s hero, this will is more than affirmative: it is declarative about what is good, noble, and worthy. The hero wills chance and Fate and calls it good, and I examine how in every respect this is opposed to envy and rivalry, to the conditions that make mimesis and sacrificial logic possible. The character of this will does not prevent the destruction of the realm, no more than Balin survived its foundation, but the noble will does reach beyond and is, I argue, all the more worthy for the poignancy of its loss and faith.

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  • Electrodeposition, Characterization, Physicochemical Properties and Application of Lead Dioxide Coatings

    Bi, Hailian (2014)

    Doctoral thesis
    The University of Auckland Library

    Lead dioxide (PbO???) coatings are materials of great interest because of their unique combination of low cost, ease of preparation, high conductivity, high oxygen overpotential, good chemical stability in corrosive media and strong catalytic ability towards organic pollutants. However, there are still main issues to be addressed for the wider application of PbO??? electrodes: (i) relatively low current densities and efficiencies for particular electrode reactions when applied in practical; (ii) long term stability, which is always a critical issue because corrosion of the coating will lead to contamination of the products with toxic Pb2+ ions. The ultimate objective of this research was to improve the electrode's efficiency and stability. To achieve this, a few strategies were taken, such as, optimisation of substrate pre-treatments, optimisation of the deposition processing parameters, incorporation of nanoparticles and doping with foreign ions on the electro-crystallization, in order to improve physicochemical properties and electrochemical performance of the PbO??? coatings. The knowledge originated from this study would shed light on a further understanding of electrocrystallisation of PbO??? and also provide a perspective on further possible improvement of the electrochemical performance of PbO??? coatings in terms of service lifetime and electrocatalytic activity. PbO??? coatings were electroplated on Ti substrates pre-coated with a Sb doped SnO??? interlayer from a traditional acidic nitrate solution. It is found that an interlayer of SnO???-Sb on Ti substrate can significantly promote the electrodeposition of PbO??? coatings. By varying electrodeposition parameters including bath temperature, deposition time, current density and Pb????? ion concentration, PbO??? coatings with various morphologies, microstructures and crystallite sizes were synthesized. A preferential crystallographic orientation was usually observed in the coatings obtained at low temperature and the coating exhibited a caterpillar-like morphology. At a higher deposition temperature a more tightly packed pyramid-like morphology was observed. The crystallite size increased with deposition temperature. In most cases, a mixture of a + b-PbO??? phase was obtained except at low current density. At a current density < 40 mA/cm??, the coating exhibited a pure b-PbO??? phase with a (301) texture and pebble-shaped morphology. In addition, the Pb????? concentration appeared to have insignificant effect on the morphology and crystallographic orientation of the PbO??? coatings. At a current density >= 40 mA/cm??, the PbO??? deposit exhibited a mixture of a + b-PbO??? phase (a dominant b-PbO??? phase with a minor a-PbO??? phase present). Moreover, the morphology of the deposits is sensitive to the corresponding current density and Pb????? concentration. It is indicated that either a sufficiently high concentration or low current density is necessary in order to obtain a compact and dense PbO??? deposit. Otherwise non-uniform or porous deposits would result from severe concentration polarization at the electrode surface. It is concluded that electrochemical performance of the deposited PbO2 largely depends on their morphologies and microstructures. High surface area, high porosity and good connectivity between crystallites play a synergic role in determining the electrochemical performance of the PbO??? coatings. Composite PbO??? electrodes were prepared by a co-deposition method from Pb????? plating solution containing either suspended nano-TiO??? particles or dissolved bismuth ions. It is found that the incorporation of nano-TiO??? particles significantly enhances the electrode's electrochemical stability. The service lifetime of the nanocomposite electrodes at the doping content of 0.8 g/L was almost three times longer than that of the undoped PbO??? electrodes. The electrochemical activity of the nanocomposite electrodes towards benzoic acid (BA) degradation was dramatically promoted, which may be attributed to the much higher overpotential for oxygen evolution and more active sites on the nanocomposite electrodes. Meanwhile, the doping of bismuth into PbO??? coating was investigated and different doping contents were employed. SEM images reveal that Bi-PbO??? coatings present a compact structure with rod-shaped deposits and X-ray diffractograms demonstrated that incorporation of bismuth did not have significant effect on the structure of PbO??? coatings. The oxygen overpotential on Bi-PbO??? electrodes is significantly higher than on undoped PbO??? electrode. The as-prepared Bi-PbO??? electrodes were employed as anodes for electrolysis of target compound and the oxidation process was monitored by high-performance liquid chromatogram (HPLC). The higher electrocatalytic ability at Bi-PbO??? can be attributed to the increased specific area of the electrodes resulted from the decrease in the size of the crystal particles, and can also be attributed to the favourable adsorption of ??OH radicals at Bi(V) sites.

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  • Measuring kelp forest productivity under current and future environmental conditions

    Rodgers, Kirsten (2014)

    Doctoral thesis
    The University of Auckland Library

    Habitat-forming kelps are important primary producers on temperate reefs worldwide, yet obtaining accurate measurements of in situ rates of photosynthesis and respiration for kelp is challenging. There is limited information about the drivers of spatial and temporal variation in net primary production (NPP), and little is known about how they will respond to climate change impacts such as warming temperatures in combination with additional stressors. Some of these information gaps are addressed in this thesis for the important habitat-forming kelp Ecklonia radiata. The primary objectives were to: (1) develop an inexpensive photorespirometry system that can be used to measure photosynthesis and respiration rates and generate photosynthetic-irradiance (P-E) curves for entire adult kelp in situ, (2) investigate season and depth-related variation in P-E curves, (3) estimate primary production (NPP) of E. radiata kelp forest using a physiologically-based model of benthic macroalgal production that incorporates in situ estimates of P-E parameters, biomass and light, and (4) investigate the interactive effects of elevated temperature and reduced light (simulating reduced water clarity) on the P-E response, productivity and resilience of adult E. radiata. The photorespirometry system that was developed consists of a polyethylene plastic bag and frame that encloses the lamina of the kelp and seals around the stipe. Water is circulated through the chamber by a closed pump system and oxygen evolution or consumption is recorded by an enclosed logger. By varying the irradiance in the chamber with shade cloth, and utilizing the variation in light associated with depth, the photosynthetic rates of an individual can be measured over a range of irradiances in situ. Using this method laboratory-derived P-E curves were compared to those obtained in situ. P-E curves from individuals measured in situ differed from those measured in the laboratory, with maximum photosynthetic rates in the laboratory being 42% and 55% lower under natural and artificial light respectively. In situ measurements of photosynthesis-irradiance relationships at two depths (6 and 14 m) over the annual cycle found that E. radiata at 14 m had higher maximum photosynthetic rates (Pmax) and photosynthetic efficiency (alpha) than kelp at 6 m. Kelp at both depths had greater photosynthetic efficiency (alpha) and reduced compensating irradiance (Ec) in winter compared to summer. Seasonal and depth-related variation in NPP of E. radiata was examined using a physiological model that incorporates in situ estimates of P-E parameters, biomass and light. Seasonal productivity patterns followed seasonal patterns of irradiance and biomass, with the highest NPP coinciding with the peak in biomass and irradiance in summer, and the minima in winter. Estimated annual production at 6 m (615 ?? 7 g C m-2 y-1)was 1.6 times greater than at 14 m (374 ?? 4 g C m-2 y-1). This was proportional to the difference in biomass of E. radiata between depths, indicating that the greater photosynthetic abilities of deeper kelp offset the effects of reduced light on overall NPP at depth. Temperature and light were manipulated in a laboratory-based mesocosm experiment and P-E curves, growth, and survival of adult kelp were measured among treatments. Kelp were also subjected to a disturbance (a period without light, simulating a large storm event), to investigate how the temperature and light treatments affected resilience. An increase in maximum water temperature (+3??C) did not greatly alter the photosynthetic response of E. radiata, but reduction in light levels had negative effects on photosynthetic capacity and rates of tissue loss. Following the disturbance, kelp had higher mortality and reduced ability to recover in the warmer treatments. These effects of increased temperature were greatest in low light treatments. To examine the overall effects on kelp productivity, the experimental findings were incorporated into a physiologically-based model of production. This predicted that under warmer conditions (+3??C) daily net primary production (NPP) in summer would be reduced by 17% at ambient light levels and 89% at low light levels. At ambient temperatures NPP was reduced by 38% under low light conditions. Following disturbance these effects were exacerbated, with negative estimates of daily NPP for both warm treatments and under reduced light at ambient temperatures. The chamber system described here provides, for the first time, a method for generating P-E curves and estimating photosynthetic parameters for entire adult kelp in situ. It can be adapted for use on other kelps and large macroalgae, and used in tank-based experiments. Importantly, the findings also indicate that estimates of productivity based on laboratory-derived photosynthesis measurements can underestimate kelp forest productivity. This research provides the first in situ P-E curves of adult kelp over the annual cycle and across multiple depths, and demonstrates how this information can be incorporated with biomass and light data in a physiologically-based model to estimate NPP of kelp. The findings highlight the importance of understanding depth-related variation in photosynthetic performance when estimating primary production of subsurface kelp forests. The results from the laboratory experiment using the chamber system to quantify the effects of elevated temperature, reduced light, and disturbance on photosynthetic performance suggest that while kelp can likely tolerate some level of warming or reduction in light, under such conditions they would be less resilient to additional perturbations and large declines in kelp productivity would be expected. Kelp forests are under threat from a variety of stressors, perhaps most importantly from climate change, and in many cases very little is known (or quantified) about many of the important services that kelp forests provide. The methods and data presented in this thesis have provided an increased understanding of E. radiata productivity and ecological function and how this important habitat-forming kelp may be impacted by climate change.

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  • A Novel Manganese Oxidising Bacterium: Characterisation and Genomic Evaluation

    Smith, Joanna (2014)

    Doctoral thesis
    The University of Auckland Library

    The production of manganese oxide minerals is predominantly mediated by microbes, resulting in the formation of highly redox active minerals which influence the geochemical cycling of many elements; including carbon, nitrogen, sulphur and many metals. This thesis describes the characterisation and genomic evaluation of a novel manganese oxidising Burkholderiales isolate, JOSHI_001, with a focus on gaining insight into the manganese depositing behaviour and ecological significance of this bacterium. This bacterium is believed to be responsible for the formation of manganese-enriched ring structures, termed anelli, present within urban stream biofilms. The results of this research are detailed within three chapters (Chapters 3 ??? 5). Chapter 3 addresses Aim 1: To investigate the occurrence of JOSHI_001, and like organisms, within urban freshwater systems; describing a field study which investigated the distribution of anelli within urban streams across the Auckland region. A correlation was found between the presence of these structures within biofilms and the level of anthropogenic impact to the site???s catchment area. Chapter 4 addresses Aim 2: To characterise JOSHI_001, as a novel manganese depositing organism; describing a polyphasic characterisation of JOSHI_001, including description of phenotypic, genomic and phylogenetic characters. This characterisation indicates that JOSHI_001 represents a novel genus and species, and we propose the name Siderocapsa amnicola. Finally, Chapter 5 addresses Aim 3: To investigate the mechanism and purpose of manganese deposition by JOSHI_001, and identify candidate manganese oxidation genes; describing an evaluation of the manganese depositing behaviour of this bacterium, using growth experiments and genomic analyses. This resulted in the identification of four candidate manganese oxidase genes of the multicopper oxidase class, tentatively designated mnxG123 and mofA on the basis of homology with these genes within the manganese oxidising bacteria Pseudomonas putida GB-1, Leptothrix cholodnii SP-6 and Leptothrix discophora SS-1. Empirical analyses indicated that manganese oxidation results from the action of an exported soluble factor, which appears to require extracellular activation. An association was found between manganese deposition, exopolymer formation and the nutritional environment, although the specific details of this association require further investigation. The purpose of manganese oxidation was also investigated, indicating that the proposed role for manganese oxides in protection of JOSHI_001 from heavy metal contaminants, which are prevalent within the urban stream environment from which this bacterium was isolated, is unlikely. This research will springboard future research to provide empirical validation of the candidate manganese oxidase genes and has provided a basis for targeted experiments to establish the purpose of this behaviour in JOSHI_001 and potentially other manganese oxidising bacteria.

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  • Dwelling within political violence: Palestinian women's narratives of home, mental health, and resilience.

    Sousa, CA; Kemp, Susan; El-Zuhairi, M (2014-11)

    Journal article
    The University of Auckland Library

    Political violence is increasingly played out within everyday civilian environments, particularly family homes. Yet, within the literature on political violence and mental health, the role of threats to home remains under-explored. Using focus group data from 32 Palestinian women, this paper explores the implications of violations to the home within political violence. Threats to the privacy, control, and constancy of the family home ??? key dimensions of ontological security (Giddens, 1990) emerged as central themes in women???s narratives. Surveillance, home invasions, and actual or threatened destruction of women???s home environments provoked fear, anxiety, grief, humiliation, and helplessness, particularly as women struggled to protect their children. Women also described how they mobilized the home for economic, familial and cultural survival. Study findings illuminate the impact of threats to intimate environments on the well-being of women and their families living with chronic political violence, and underscore the importance of attention to violations of place and home in research on civilian experiences of and responses to political violence.

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  • Strengths-based practice and parental engagement in child welfare services: An empirical examination

    Kemp, Susan; Marcenko, MO; Lyons, SJ; Kruzich, JM (2014-12)

    Journal article
    The University of Auckland Library

    Child welfare policy and practice increasingly emphasize the use of strength-based practice in concert with efforts to reduce identified risks to child safety. Compared with strategies for assessing risk, however, strength-based child welfare interventions lack a robust empirical foundation. Using data from a linked sample of primary caregivers (n = 679) and child welfare caseworkers (n = 327), the present study used path analysis to examine the relationship between parent report of workers' use of strength-based practice and parent investment in child welfare services. The study also examined the role of worker characteristics, organizational factors, child placement status, and parent risk factors. As hypothesized, parents' perceptions regarding their workers' use of strength-based practices robustly predicted their buy-in to services. Furthermore, those parents with a child in out-of-home placement, compared to those receiving in-home services, were less likely to perceive their worker as strength-based or to engage in services. The only significant organizational variable was workers' positive challenge, directly influencing strength-based practices and indirectly affecting parent engagement. Further, parents who reported using substances and those experiencing more economic hardship were more likely to buy-in to services. The findings provide empirical support for the link between parents' willingness to engage in services and the use of strength-based interventions, and contribute to current discussions regarding the appropriate balance between reducing risks to child safety and strengthening family capacities.

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  • Review of the book: Weavers of Dreams, Unite! Actors' Unionism in Early Twentieth-Century America, by Sean P. Holmes

    Taillon, Paul (2014-06-01)

    Unclassified
    The University of Auckland Library

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  • Grand accomplishments in social work

    Sherraden, M; Stuart, P; Angell, B; Barth, RP; Mahoney, K; Kemp, Susan; Brekke, J; Lubben, J; Padilla, Y; Hawkins, JD; DiNitto, D; Coulton, C; Padgett, D; McRoy, R; Schroepfer, T; Walters, K; Catalano, R; Healy, L (2014-02)

    Report
    The University of Auckland Library

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  • Partial protective effect of intranasal immunization with recombinant Toxoplasma gondii rhoptry protein 17 against toxoplasmosis in mice

    Wang, H-L; Zhang, T-E; Yin, L-T; Pang, M; Guan, L; Liu, H-L; Zhang, J-H; Meng, X-L; Bai, Jizhong; Zheng, G-P; Yin, G-R (2014-09-25)

    Journal article
    The University of Auckland Library

    Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite that infects a variety of mammals, including humans. An effective vaccine for this parasite is therefore needed. In this study, RH strain T. gondii rhoptry protein 17 was expressed in bacteria as a fusion with glutathione S-transferase (GST) and the recombinant proteins (rTgROP17) were purified via GST-affinity chromatography. BALB/c mice were nasally immunised with rTgROP17, and induction of immune responses and protection against chronic and lethal T. gondii infections were investigated. The results revealed that mice immunised with rTgROP17 produced high levels of specific anti-rTgROP17 IgGs and a mixed IgG1/IgG2a response of IgG2a predominance. The systemic immune response was associated with increased production of Th1 (IFN-??and IL-2) and Th2 (IL-4) cytokines, and enhanced lymphoproliferation (stimulation index, SI) in the mice immunised with rTgROP17. Strong mucosal immune responses with increased secretion of TgROP17-specific secretory IgA (SIgA) in nasal, vaginal and intestinal washes were also observed in these mice. The vaccinated mice displayed apparent protection against chronic RH strain infection as evidenced by their lower liver and brain parasite burdens (59.17% and 49.08%, respectively) than those of the controls. The vaccinated mice also exhibited significant protection against lethal infection of the virulent RH strain (survival increased by 50%) compared to the controls. Our data demonstrate that rTgROP17 can trigger strong systemic and mucosal immune responses against T. gondii and that ROP17 is a promising candidate vaccine for toxoplasmosis.

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  • Climate change and health: on the latest IPCC report

    Woodward, Alistair; Smith, KR; Campbell-Lendrum, D; Chadee, DD; Honda, Y; Liu, Q; Olwoch, J; Revich, B; Sauerborn, R; Chafe, Z; Confalonieri, U; Haines, A (2014-04-05)

    Journal article
    The University of Auckland Library

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  • Florida Automated Water Conservation Estimation Tool overview

    Castaneda, MA; Mason, Andrew; Geursen, V (2014-04)

    Journal article
    The University of Auckland Library

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  • Sildenafil alters retinal function in mouse carriers of Retinitis Pigmentosa

    Nivison-Smith, L; Zhu, Y; Whatham, A; Bui, BV; Fletcher, EL; Acosta Etchebarne, Monica; Kalloniatis, Michael (2014-11)

    Journal article
    The University of Auckland Library

    Sildenafil, the active ingredient in Viagra, has been reported to cause transient visual disturbance from inhibition of phosphodiesterase 6 (PDE6), a key enzyme in the visual phototransduction pathway. This study investigated the effects of sildenafil on the rd1(+/-) mouse, a model for carriers of Retinitis Pigmentosa which exhibit normal vision but may have a lower threshold for cellular stress caused by sildenafil due to a heterozygous mutation in PDE6. Sildenafil caused a dose-dependent decrease in electroretinogram (ERG) responses of normal mice which mostly recovered two days post administration. In contrast, rd1(+/-) mice exhibited a significantly reduced photoreceptor and a supernormal bipolar cell response to sildenafil within 1 h of treatment. Carrier mice retinae took two weeks to return to baseline levels suggesting sildenafil has direct effects on both the inner and outer retina and these effects differ significantly between normal and carrier mice. Anatomically, an increase in expression of the early apoptotic marker, cytochrome C in rd1(+/-) mice indicated that the effects of sildenafil on visual function may lead to degeneration. The results of this study are significant considering approximately 1 in 50 people are likely to be carriers of recessive traits leading to retinal degeneration.

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  • Vinpocetine regulates cation channel permeability of inner retinal neurons in the ischaemic retina

    Nivison-Smith, L; Acosta Etchebarne, Monica; Misra, Stuti; O'Brien, BJ; Kalloniatis, Michael (2014-01)

    Journal article
    The University of Auckland Library

    Vinpocetine is a natural drug which exerts neuroprotective effects in ischaemia of the brain through actions on cation channels, glutamate receptors and other pathways. This study investigated the effect of vinpocetine on cation channel permeability of inner retinal neurons after acute retinal metabolic insult. We focused on amacrine and ganglion cells immunoreactive for calretinin or parvalbumin due to their previously documented susceptibility to ischaemia. Using the probe, 1-amino-4-guanidobutane (AGB), we observed increased cation channel permeability across amacrine and ganglion cells under ischaemia and hypoglycaemia but not anoxia. Calretinin and parvalbumin immunoreactivity was also reduced during ischaemia and hypoglyacemia but not anoxia. Vinpocetine decreased AGB entry into ischaemic and hypoglycaemic ganglion cells indicating that the drug can modulate unregulated cation entry. In addition, vinpocetine prevented the loss of calretinin and parvalbumin immunoreactivity following ischaemia suggesting it may indirectly regulate intracellular calcium. Vinpocetine also reduced AGB permeability in selected amacrine and ganglion cell populations following N-methyl-D-aspartate (NMDA) but not kainate activation suggesting that vinpocetine's regulation of cation channel permeability may partly involve NMDA sensitive glutamate receptors.

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  • Gap junction proteins in the light-damaged albino rat

    Guo, Xiaopeng; Tran, H; Green, Colin; Danesh-Meyer, Helen; Acosta Etchebarne, Monica (2014-05-27)

    Journal article
    The University of Auckland Library

    PURPOSE: Changes in connexin expression are associated with many pathological conditions seen in animal models and in humans. We hypothesized that gap junctions are important mediators in tissue dysfunction and injury processes in the retina, and therefore, we investigated the pattern of connexin protein expression in the light-damaged albino rat eye. METHODS: Adult Sprague-Dawley rats were exposed to intense light for 24 h. The animals were euthanized, and ocular tissue was harvested at 0 h, 6 h, 24 h, 48 h, and 7 days after light damage. The tissues were processed for immunohistochemistry and western blotting to analyze the expression of the gap junction proteins in the light-damaged condition compared to the non-light-damaged condition. Cell death was detected using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) technique. RESULTS: Intense light exposure caused increased TUNEL labeling of photoreceptor cells. Immunocytochemistry revealed that connexin 36 (Cx36) was significantly increased in the inner plexiform layer and Cx45 was significantly decreased in the light-damaged retina. The pattern of Cx36 and Cx45 labeling returned to normal 7 days after light damage. Cx43 significantly increased in the RPE and the choroid in the light-damaged tissue, and decreased but not significantly in the retina. This elevated Cx43 expression in the choroid colocalized with markers of nitration-related oxidative stress (nitrotyrosine) and inflammation (CD45 and ionized calcium-binding adaptor molecule-1) in the choroid. CONCLUSIONS: The results suggest that connexins are regulated differently in the retina than in the choroid in response to photoreceptor damage. Changes in connexins, including Cx36, Cx43, and Cx45, may contribute to the damage process. Specifically, Cx43 was associated with inflammatory damage. Therefore, connexins may be candidate targets for treatment for ameliorating disease progression.

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