21,782 results for 2000, Journal article

  • Basal cell carcinoma mistaken for actinic keratosis.

    Jacobs, Robert; Phillips, Geraint (2006-05)

    Journal article
    The University of Auckland Library

    Increasing age and UV exposure are well-known associations with precancerous and cancerous skin lesions, including actinic (solar) keratosis, and squamous and basal cell carcinomata. This report describes a patient with a facial skin lesion close to an eye that was initially believed to be actinic (solar) keratosis but was subsequently diagnosed as a basal cell carcinoma (BCC). The diagnosis of BCC was helped pre-operatively by manipulation of the surrounding facial skin, which revealed the characteristic rolled edges and telangiectasis. Referral to his general medical practitioner (GP) resulted in surgical excision of the lesion. This procedure was performed inexpensively by the local GP as the lesion was not large and was in an accessible position. The lesion and the course of recovery over four weeks were documented photographically. The lesion was surgically excised and the diagnosis of basal cell carcinoma was confirmed by pathological examination. The wound healed well and the final cosmetic result was excellent. This patient illustrates the importance of careful observation and photo-documentation of suspicious skin lesions. A review of the treatment options for these lesions is included in this report.

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  • A Semantic Web Environment for Components

    Wang, HH; Sun, Jing (2009)

    Journal article
    The University of Auckland Library

    Component-based development (CBD) has become an important emerging topic in the software engineering field. It promises long-sought-after benefits such as increased software reuse, reduced development time to market and, hence, reduced software production cost. Despite the huge potential, the lack of reasoning support and development environment of component modeling and verification may hinder its development. Methods and tools that can support component model analysis are highly appreciated by industry. Such a tool support should be fully automated as well as efficient. At the same time, the reasoning tool should scale up well as it may need to handle hundreds or even thousands of components that a modern software system may have. Furthermore, a distributed environment that can effectively manage and compose components is also desirable. In this paper, we present an approach to the modeling and verification of a newly proposed component model using Semantic Web languages and their reasoning tools. We use the Web Ontology Language and the Semantic Web Rule Language to precisely capture the inter-relationships and constraints among the entities in a component model. Semantic Web reasoning tools are deployed to perform automated analysis support of the component models.Moreover, we also proposed a service-oriented architecture (SOA)-based semantic web environment for CBD. The adoption of Semantic Web services and SOA make our component environment more reusable, scalable, dynamic and adaptive.

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  • Development of a Controlled Release System for Risperidone Using Polypyrrole: Mechanistic Studies

    Svirskis, Darren; Wright, Bryon; Travas-Sejdic, Jadranka; Rodgers, A; Garg, Sanjay (2010)

    Journal article
    The University of Auckland Library

    Polypyrrole (PPY) film has been selected as a platform material for drug delivery due to its inherent conductivity, ease of preparation and apparent biocompatibility. PPY films were prepared containing the antipsychotic drug risperidone as a model compound. Drug release profiles could be altered by applying different electrical stimulation to these films. Atomic force microscopy was used to investigate changes in PPY film thickness when different stimuli were applied. The highest levels of drug release were observed when PPY was reduced; this was accompanied by expansion of the film. Technology such as this could be utilized for implantable drug delivery devices, where the dose could be adjusted by external signaling.

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  • Advances in Process Control for Aluminium Smelters

    Taylor, Mark; Chen, JJJ (2007)

    Journal article
    The University of Auckland Library

    As amperages have increased on existing plants and environmental and energy constraints have tightened on both new and existing ones, smelter control has become the biggest leverage point for not only cost reduction and product quality improvement, but also for environmental compliance. The license to operate smelters now is becoming increasingly dependent on the reputation of companies for close control of their operations. This licence is even more important for companies building new smelters. The present article addresses some of the issues smelter practitioners, designers, and engineers face on a daily basis concerning the drivers of smelter process variation and the levers to reduce it. A step change in the understanding and thinking about control is required first at a managerial level, and this change is discussed. Better education concerning process control is essential for engineers and scientists so that more rigorous analysis of plant control defects and failures can occur on a broad front. This is the second important advance required. The third major advance concerns research and development to provide tools for multivariate, non-stationary processes that have extreme observability, controllability, and criticality characteristics. This describes some but not all of the features that are encountered in the control of aluminium smelters. Some promising research directions and applications are discussed.

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  • The effect of time of day on the duration of neuromuscular blockade elicited by rocuronium

    Cheeseman, James; Merry, Alan; Pawley, Matthew; De Souza, RL; Warman, Guy (2007)

    Journal article
    The University of Auckland Library

    In a prospective, observational trial, we investigated the influence of time of day on the duration of neuromuscular blockade (NMB) elicited by rocuronium. Forty-nine patients scheduled for surgery between 08:00 and 02:00 were enrolled after giving written informed consent. Time to neuromuscular recovery was measured following three doses: (1) a fat-free-mass (FFM) related induction dose (0.6 mg.kg)1: n = 47); (2) a maintenance dose (20% of the induction dose: n = 42); and (3) a standard 10-mg dose (n = 35). The extent of NMB was dependent on the time of administration (p = 0.038 General Linear Model Analysis). The maximum effect of 50 min (95% CI 41???59 min) was elicited between 08:00 and 11:00 and the minimum duration of 29 min (95% CI 23???35 min) between 14:00 and 17:00 (p = 0.005). A similar pattern was observed for the maintenance dose. The duration of action of rocuronium is influenced by time of day and this effect is of potential clinical significance and practical relevance to research.

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  • Drag enhancement of aqueous electrolyte solutions in turbulent pipe flow

    Doherty, AP; Spedding, PL; Chen, JJJ (2010)

    Journal article
    The University of Auckland Library

    ABSTRACT: Experimental measurements have indicated that drag enhancement occurs when aqueous electrolyte solutions are flowing in the turbulent regime. The primary electroviscous effect due to the distortion by the shear field of the electrical double layer surrounding the ions in solution is invoked to explain the drag enhancement. Calculations using the Booth model for symmetrical one-to-one electrolytes enabled the increased viscosity in the turbulent regime to be calculated.

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  • Three-dimensional elastohydrodynamics of a thin plate oscillating above a wall

    Clarke, Richard; Jensen, OE; Billingham, J (2008)

    Journal article
    The University of Auckland Library

    We consider deflections of a thin rectangular elastic plate that is submerged within a Newtonian fluid. The plate is clamped along one edge and supported horizontally over a plane horizontal wall. We consider both external driving, where the clamped edge is vibrated vertically at high frequencies, and thermal driving, where the plate fluctuates under Brownian motion. In both cases, the amplitude of oscillation is assumed sufficiently small that the resulting flow has little convective inertia, although the oscillation frequency is sufficiently high to generate substantial unsteady inertia in the flow, a common scenario in many nano- and microdevices. We exploit the plate???s thinness to develop an integral-equation representation for the three-dimensional flow a so-called thin-plate theory which offers considerable computational savings over a full boundary-integral formulation. Limiting cases of high oscillation frequencies and small wall-plate separation distances are studied separately, leading to further simplified descriptions for the hydrodynamics. We validate these reduced integral representations against full boundary-integral computations, and identify the parameter ranges over which these simplified formulations are valid. Addressing the full flow-structure interaction, we also examine the limits of simpler two-dimensional hydrodynamic models. We compare the responses of a narrow plate under two- and three-dimensional hydrodynamic loading, and report differences in the frequency response curves that occur when the plate operates in water, in contrast to the excellent agreement observed in air.

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  • Ecological diversification in habitat use by subtidal triplefin fishes (Tripterygiidae)

    Wellenreuther, Maren; Barrett, Peter; Clements, Kendall (2007)

    Journal article
    The University of Auckland Library

    ABSTRACT: Recent work has shown that habitat specialisation can lead to diversification in lacustrine and marine fish species. Here we investigate specialisation in the New Zealand triplefin fish fauna (Tripterygiidae), which has the greatest diversity and disparity of triplefin species in the world with 26 endemic species. Most species are sympatric throughout coastal New Zealand, showing no obvious latitudinal trends in abundance. We sampled habitat use quantitatively, and microposition qualitatively, in 17 triplefin species at 151 sites representing a geographic range from 35?? 50??? S to 46?? 70??? S. A novel Euclidean-distance non-metric multidimensional scaling (MDS) technique was used to display the quantitative habitat variables (depth, fetch, rock, cobble, gravel, sand, mud, macroalgae, and coralline and turfing algae) of each species. For each species, the positions of these variables were compared to those of all species using Procrustes configural matrix comparison methodology, which resulted in a final 3D spatial representation of species using non-metric MDS. Our results demonstrate that triplefin species have diversified considerably in habitat and microposition use, resulting in species occupying different patches in the same general location. Strong habitat partitioning was shown by 3 distinct clusters of species along a gradient of depth and exposure. Some species showed an even finer sub-partitioning by using different substratum types, in particular rock and mud. Correspondence Analysis of microposition data showed that 5 species differed from all other species, further partitioning habitat use. Thus, our results suggest that habitat use has been important in the diversification of New Zealand triplefin fishes.

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  • A novel watermarking method for software protection in the cloud

    Yu, Zhiwei; Wang, Chaokun; Thomborson, Clark; Wang, Jianmin; Lian, Shiguo; Vasilakos, Athanasios V (2011)

    Journal article
    The University of Auckland Library

    With the rapid development of cloud computing, software applications are shifting onto cloud storage rather than remaining within local networks. Software distributions within the cloud are subject to security breaches, privacy abuses, and access control violations. In this paper, we identify an insider threat to access control which is not completely eliminated by the usual techniques of encryption, cryptographic hashes, and access-control labels. We address this threat using software watermarking. We evaluate our access-control scheme within the context of a Collaboration-oriented Architecture, as defined by The Jericho Forum.

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  • A double dissociation between striate and extrastriate visual cortex for pattern motion perception revealed using rTMS.

    Thompson, Benjamin; Aaen-Stockdale, C; Koski, L; HESS, RF (2009)

    Journal article
    The University of Auckland Library

    The neural mechanisms underlying the integration and segregation of motion signals are often studied using plaid stimuli. These stimuli consist of two spatially coincident dynamic gratings of differing orientations, which are either perceived to move in two unique directions or are integrated by the visual system to elicit the percept of a checkerboard moving in a single direction. Computations pertaining to the motion of the individual component gratings are thought to take place in striate cortex (V1) whereas motion integration is thought to involve neurons in dorsal stream extrastriate visual areas, particularly V5/MT. By combining a psychophysical task that employed plaid stimuli with 1 Hz offline repetitive transcranial magnetic stimulation (rTMS), we demonstrated a double dissociation between striate and extrastriate visual cortex in terms of their contributions to motion integration. rTMS over striate cortex increased coherent motion percepts whereas rTMS over extrastriate cortex had the opposite effect. These effects were robust directly after the stimulation administration and gradually returned to baseline within 15 minutes. This double dissociation is consistent with previous patient data and the recent hypothesis that both coherent and transparent motion percepts are supported by the visual system simultaneously and compete for perceptual dominance

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  • International students as urban agents: International education and urban transformation in Auckland, New Zealand

    Collins, Francis (2010)

    Journal article
    The University of Auckland Library

    This paper discusses connections between the internationalisation of education, and in particular the growth in international students, and processes of urban transformation. The research is centred in Auckland, New Zealand, a city where the number of international students has grown rapidly over the last decade leading to significant impacts on the urban form and experience of the city???s CBD. This includes growth in educational services such as language schools and other private training establishments, new residential geographies characterised by low-cost and low-quality high-rise developments, and new ethnic economies of food, service and entertainment businesses that explicitly target international students. The paper draws on research with South Korean international students and a range of secondary materials to interrogate the connections between student mobilities and changing urban form. In doing so the paper contributes to emerging scholarship on student geographies and the role of students as urban agents through the inclusion of an international dimension that has largely been absent in the extant literature. The findings illustrate that while international students themselves clearly play a significant role in the transformation of urban spaces their influence cannot easily be separated from the contribution of a range of other actors including educational businesses, property developers, transnational migrants and local and national state actors.

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  • Languages of Labor: Negotiating the "Real" and the Relational in Indo-Fijian Women's Expressions of Physical Pain.

    Trnka, Susanna (2007)

    Journal article
    The University of Auckland Library

    Medical personnel in public clinics in Fiji routinely contend that state-funded medical resources are misallocated on patients who complain of, but do not actually experience, physical pain. Frequently, these patients are identified as being Indo-Fijian women (i.e., women of South Asian origin in Fiji). In this article, I examine clinical interactions between medical staff and female Indo-Fijian patients to demonstrate how ???real??? and ???unreal??? pain are distinguished in the clinical setting and to indicate some of the roles clinical encounters play in community processes that ascribe alternative meanings to physical pain. Focusing on how both physicians and women patients foster certain interpretations of physical pain over others, I argue that the category of ???unreal??? pain, as employed by Fiji???s physicians, consists of pain that medical professionals consider to be induced by psychological or physical, work-related stresses. I then show how Indo-Fijian women engage in a complementary but distinct discourse that emphasizes links between physical labor and pain and suggests that, in some cases, expressions of physical pain are as much an idiom of pride as an idiom of distress.

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  • Supermarket sales data: feasibility and applicability in population food and nutrition monitoring

    Tin Tin, S; Ni Mhurchu, C; Bullen, Christopher (2007)

    Journal article
    The University of Auckland Library

    Population food and nutrition monitoring plays a critical role in understanding suboptimal nutrition at the population level, yet current monitoring methods such as national surveys are not practical to undertake on a continuous basis. Supermarket sales data potentially address this gap by providing detailed, timely, and inexpensive monitoring data for informing policies and anticipating trends. This paper reviews 22 studies that used supermarket sales data to examine food purchasing patterns. Despite some methodological limitations, feasibility studies showed promising results. The potential and limitations of using supermarket sales data to supplement food and nutrition monitoring methods are discussed.

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  • Steady-State Flat Pickup Loading Effects in Poly-Phase Inductive Power Transfer Systems

    Kissin, MLG; Covic, Grant; Boys, John (2011)

    Journal article
    The University of Auckland Library

    Polyphase inductive power transfer systems have been proposed as a method of increasing the tolerance of roadway- based vehicular systems to the lateral movement of pickups. However, the design of the power supply is challenging due to the changing nature of the load presented by mobile pickups. An inverter driving a traditional single-phase system must be designed with only the peak power in mind, as the reactive load of the pickups is essentially constant due to the relatively constrained pickup movement and will normally be compensated when the system is designed. This is not possible for an inverter driving a polyphase track, as the reactive load will vary with the lateral position of the pickup, just as a portion of the real load that must be supplied by each phase will also vary. This paper presents a simple but accurate method of determining the real and reactive load on each phase of the track as the pickup moves, allowing the inverter to be correctly designed with appropriate component ratings.

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  • A series tuned AC Processing Pickup with a controllable AC-voltage output

    Wu, HH; Covic, Grant; Boys, John; Robertson, DJ (2011)

    Journal article
    The University of Auckland Library

    This paper presents a new type of series ac-processing pickup used in inductive-power-transfer applications. The proposed pickup uses an ac switch operating under zero-currentswitching conditions in series with a resonant network to produce a controllable ac voltage source suitable for driving incandescent lights. When a recti???er is cascaded onto this pickup, it can also produce a precisely controlled dc voltage. This topology eliminates the need to use an extra buck converter after the traditional series pickup for controlling the output load voltage to a desired value, which may be different from the induced voltage of the pickup. Furthermore, this pickup has the ability to control the inductor current directly, and hence, eliminate the transient inrush current at startup for the series-tuned resonant tank. The circuit is analytically analyzed and the maximum ef???ciency for a 1.2-kW prototype is measured to be 93%.

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  • A dynamic model of excitation-contraction coupling during acidosis in cardiac ventricular myocytes

    Crampin, Edmund; Smith, NP (2006)

    Journal article
    The University of Auckland Library

    Acidosis in cardiac myocytes is a major factor in the reduced inotropy that occurs in the ischemic heart. During acidosis, diastolic calcium concentration and the amplitude of the calcium transient increase, while the strength of contraction decreases. This has been attributed to the inhibition by protons of calcium uptake and release by the sarcoplasmic reticulum, to a rise of intracellular sodium caused by activation of sodium-hydrogen exchange, decreased calcium binding affinity to Troponin-C, and direct effects on the contractile machinery. The relative contributions and concerted action of these effects are, however, difficult to establish experimentally. We have developed a mathematical model to examine altered calcium-handling mechanisms during acidosis. Each of the alterations was incorporated into a dynamical model of pH regulation and excitation-contraction coupling to predict the time courses of key ionic species during acidosis, in particular intracellular pH, sodium and the calcium transient, and contraction. This modeling study suggests that the most significant effects are elevated sodium, inhibition of sodiumcalcium exchange, and the direct interaction of protons with the contractile machinery; and shows how the experimental data on these contributions can be reconciled to understand the overall effects of acidosis in the beating heart.

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  • Cohesin-dependent regulation of runx genes

    Horsfield, Julia; Anagnostou, SH; Crosier, Kathryn; Crosier, Philip (2006)

    Journal article
    The University of Auckland Library

    Runx transcription factors determine cell fate in many lineages. Maintaining balanced levels of Runx proteins is crucial, as deregulated expression leads to cancers and developmental disorders. We conducted a forward genetic screen in zebrafish for positive regulators of runx1 that yielded the cohesin subunit rad21. Zebrafish embryos lacking Rad21, or cohesin subunit Smc3, fail to express runx3 and lose hematopoietic runx1 expression in early embryonic development. Failure to develop differentiated blood cells in rad21 mutants is partially rescued by microinjection of runx1 mRNA. Significantly, monoallelic loss of rad21 caused a reduction in the transcription of runx1 and of the proneural genes ascl1a and ascl1b, indicating that downstream genes are sensitive to Rad21 dose. Changes in gene expression were observed in a reduced cohesin background in which cell division was able to proceed, indicating that cohesin might have a function in transcription that is separable from its mitotic role. Cohesin is a protein complex essential for sister chromatid cohesion and DNA repair that also appears to be essential for normal development through as yet unknown mechanisms. Our findings provide evidence for a novel role for cohesin in development, and indicate potential for monoallelic loss of cohesin subunits to alter gene expression.

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  • Zebrafish runx1 promoter-EGFP transgenics mark discrete sites of definitive blood progenitors

    Lam, EY; Chau, JK; Kalev-Zylinska, Maggie; Fountaine, TM; Mead, RS; Hall, Christopher; Crosier, Philip; Crosier, Kathryn; Flores, Maria (2009)

    Journal article
    The University of Auckland Library

    The transcription factor Runx1 is essential for the development of de???nitive hematopoietic stem cells (HSCs) during vertebrate embryogenesis and is transcribed from 2 promoters, P1 and P2, generating 2 major Runx1 isoforms. We have created 2 stable runx1 promoter zebra???shtransgenic lines that provide insight into the roles of the P1 and P2 isoforms during the establishment of de???nitive hematopoiesis. The Tg(runx1P1:EGFP) line displays ???uorescence in the posterior blood island, where de???nitive erythromyeloid progenitors develop. The Tg(runx1P2:EGFP) line marks de???nitive HSCs in the aortagonad-mesonephros, with enhanced green ???uorescent protein???labeled cells later populating the pronephros and thymus. This suggests that a function of runx1 promoter switching is associated with the establishment of discrete de???nitive blood progenitor compartments. These runx1 promoter???transgenic lines are novel tools for the study of Runx1 regulation and function in normal and malignant hematopoiesis. The ability to visualize and isolate ???uorescently labeled HSCs should contribute to further elucidating the complex regulation of HSC development.

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  • Generalising the Kuromoto Model for the study of Neuronal Synchronisation in the Brain

    Cumin, David; Unsworth, Charles (2007)

    Journal article
    The University of Auckland Library

    In this article, we have generalised the Kuramoto model to allow one to model neuronal synchronisation more appropriately. The generalised version allows for different connective arrangements, time-varying natural frequencies and time-varying coupling strengths to be realised within the framework of the original Kuramoto model. By incorporating the above mentioned features into the original Kuramoto model one can allow for the adaptive nature of neurons in the brain to be accommodated. Extensive tests using the generalised Kuramoto model were performed on a N = 4 coupled oscillator network. Examination of how different connective arrangements, time-varying natural frequencies and time-varying coupling strengths affected synchronisation separately and in combination are reported. The effects on synchronisation for large N are also reported.

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  • Simulators for use in anaesthesia

    Cumin, David; Merry, Alan (2007)

    Journal article
    The University of Auckland Library

    There are many simulators available for use in anaesthetic-related education and research. Those who wish to purchase a simulator or to establish a simulation facility face a daunting task in understanding the differences between simulators. Recent reviews have focused on narrower areas of simulation, such as airway management or basic life support, or on the application of simulators. It would be dif???cult to deal in detail with every simulator ever made for anaesthesia, but in the present review we cover the spectrum of currently available anaesthetic simulators, provide an overview of different types of simulator, and discuss a selection of simulators of particular interest, including some of historical signi???cance and some examples of ???home made??? simulators. We have found no common terminology amongst authors for describing or classifying simulators, and propose a framework for describing (or classifying) them that is simple, clear and applicable to any simulator.

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