231 results for Conference poster

  • Test- retest reliability of an instrumented elastometer for measuring passive stiffness of the levator ani muscle

    Kruger, Jennifer; Nielsen, Poul; Dietz, HP; Taberner, Andrew (2011-08-31)

    Conference poster
    The University of Auckland Library

    Hypothesis / aims of study Clinical evidence demonstrates strong associations between vaginal birth, the incidence of levator ani (LA) muscle injury, and a decrease in muscle function (1). Imaging modalities such as ultrasound and magnetic resonance imaging have provided insight into the nature of LA injury, confirming that it is significantly implicated in the development of pelvic organ prolapse (2). Strain of the LA muscles during delivery of the fetal head is considerable, and childbirth related trauma to the muscle has been shown to occur in 10-30% of women delivering vaginally (1,2). Thus, developing measures to identify a-priori, those who are most likely to suffer from injury during vaginal birth should be a high research priority. The inherent elasticity of the muscle clearly plays a role in the ability of the muscle to accommodate the fetal head. However, measuring passive stiffness of the muscle in vivo remains challenging. The aim of this study was to further develop and test a novel elastometer (3), designed to estimate in vivo passive stiffness produced by the puborectalis component of the LA muscle, where it passes in close contact with the lateral walls of the vagina, from its origin on the pubic ramus. Study design, materials and methods The elastometer used in this study is a more sophisticated version of a previously developed first-generation device (3). The current version of this instrument (Figure 1) boasts enhanced aesthetics and patient friendliness compared to our previous device. Notably, our elastometer can now implement user-defined measurement protocols under automatic computer control in order to measure the force-displacement characteristics of the LA muscle. The device consists of a hand-piece comprising two aluminium arms, with detachable acetyl plastic speculum ends, actuated by a DC servo mechanism via a load cell. A load cell amplifier and displacement transducer are integrated into the hand-piece, providing force and speculum separation measurements. The hand-piece is connected to a control box that communicates with a laptop computer via a USB connection. The control box contains a data-acquisition device (USB-6009, National Instruments), motor drive circuit, and battery-based power supply. A custom MSWindows application implements a closed-loop motor control algorithm on the laptop, records measurements of speculum displacement and force, and provides feedback to the user. The laptop user-interface displays speculum separation and force on a strip chart, together with a force-displacement graph. The design of the speculum end of the elastometer is such that the tip is wider than the neck, (26mm compared to 18mm) to reduce the likelihood of perineal muscles confounding measurement of passive stiffness. Magnetic clips attach the speculum ends to the device which allows for easy cleaning, and provides the facility of attaching speculums of various sizes. Reliability and repeatability of the elastometer was assessed in 12 volunteers. None of the participants had had vaginal surgery, or any contraindications for vaginal examination. All participants were tested twice, 3 to 5 days apart using the same protocol. The speculum was inserted to the level of the puborectalis muscle (2-4 cm from the introitus) orientated in the coronal plane. After initial familiarisation with the device in situ, recording of the data commenced. All participants were encouraged to remain relaxed during the experiment. Data acquisition was automated with the device opening in 20 stepwise increments, to the desired separation, over 60 seconds. Data were collected at a frequency of 100 Hz. Averaged data over a three second period gave 21 data points per test. The procedure was repeated three times, with the initial run being considered as a preconditioning step and not used for data analysis. Statistical analysis was carried out using “R” version 2.12.2 (Copyright (C) 2011 The R Foundation for Statistical Computing). Results from Day 1 were compared with the re-test results using Bland/Altman repeated measures to determine any bias and limits of agreement and Intraclass correlation co-efficient (ICC) to determine reliability across tests and Days. Results The mean age of the 12 participants was 44.3 years (range 26 to 58 years), BMI 26 kg/m2 (range 20.4 to 33.7 kg/m2). Two of these were nulliparous, with the median number of vaginal delivery being 2. Data was visualised in graphic form for each subject across all tests for both days. A representative plot from one subject is shown in Figure 2. ICC’s for the second and third tests respectively were 0.92 (CI 0.89- 0.93), and 0.86 (CI 0.82-0.89). Limits of agreement (from repeated measures Bland Altman) were -2.79 N to +2.31 N, with a mean difference of -0.21 N. Interpretation of results Repeated Bland Altman demonstrates minimal bias with the mean difference close to zero at -0.12 N. The 95% limits of agreement range was slightly over 4 N, and likely to be due to biological variability. The high Intraclass correlation co-efficient for both tests between Days indicate minimal variability of the measurements. Concluding message This second generation elastometer has proved reliable and consistent in the measurement of passive stiffness of the puborectalis muscle in this group of volunteers. These results confirm satisfactory performance of the instrument in preparation for future studies validating this method in clinical and research settings. References 1. DeLancey JO. The hidden epidemic of pelvic floor dysfunction: achievable goals for improved prevention and treatment. Am J Obstet Gynecol. 2005 May;192(5):1488-95. 2. Dietz HP, Simpson JM. Levator trauma is associated with pelvic organ prolapse. BJOG. 2008 Jul;115(8):979-84. 3. Kruger J, et al.. Pelvic floor muscle compliance in Elite nulliparous Athletes. 38th Annual meeting of the International Continence Society. Cario 2008

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  • A frontline perspective of organizational change: Analyzing the creation of a Youth Justice entity in Child, Youth and Family using Lewin, Kotter & Schein's change management and organizational culture models

    Webster, Michael; Herrmann, K (2009-03-19)

    Conference poster
    The University of Auckland Library

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  • A case study on frontline perspectives of organizational change: A practitioner-academic partnership to analyse the creation of a Youth Justice entity in Child, Youth and Family

    Webster, Michael; Herrmann, Klaus (2009-11-11)

    Conference poster
    The University of Auckland Library

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  • Cells isolated from adult human brain. Are they fibroblasts, neural stem cells or both?

    Park, In; Gibbons, Hannah; Mee, EW; Teoh, HH; Faull, Richard; Dragunow, Michael (2009)

    Conference poster
    The University of Auckland Library

    The discovery of endogenous neural progenitor cells (NPCs) in the adult human brain capable of migrating and differentiating in response to external stimuli has re-defined the field of neuroscience. In order to study and characterize these NPCs, research groups have attempted to culture them in vitro with varying success. Adult human NPCs are generally cultured from the two major neurogenic regions of the brain; the subventricular zone (SVZ) and the dentate gyrus of the hippocampus. However, we propose that cells with similar characteristics to NPCs can be isolated and cultured from other regions of the adult human brain. Briefly, human brain cells were isolated from the middle temporal gyrus (MTG) of post-mortem and biopsy tissue and diced into small pieces prior to enzymatic digestion. The dissociated cells were plated onto poly-L-lysine (PLL) coated culture flasks. Initially the cells were maintained in media consisting of 10% serum, DMEM:F12 media supplemented with 2mM glutamine and antibiotics at 5% CO2/37ºC. Once confluent, the cells were re-plated into conditions favourable for NPC growth (serum free Neurobasal medium supplemented with N2, 2mM GlutaMAX® and antibiotics or commercially available STEMPRO® medium (Invitrogen)) in either adherent monolayer cultures or non-adherent surfaces for the formation of spheres. When cells from the MTG were cultured in 10% serum, the dominating cell type that arose after prolonged culture periods were fibroblast-like cells (FbCs), which were highly proliferative and expressed high levels of fibroblast markers. However, when cultured under NPC conditions, FbCs became bipolar in morphology and strongly expressed genes associated with NPCs such as nestin, GFAP and GFAP-δ and βIII-tubulin. These expression patterns partially resembled those seen with adherent adult human NPCs isolated from the SVZ. Furthermore, when FbCs were cultured on non-adhesive surfaces, they formed spherical structures resembling neurospheres formed from adult human SVZ-derived NPCs. When these FbC-spheres were plated onto adhesive surfaces they gave rise to cells expressing immature neuronal markers. Although further investigation is needed, these results suggest that more than one cell type from the adult human brain in vitro possesses stem cell-like properties. The origin of these FbCs is yet to be determined, however, leptomeningeal or blood-born mesenchymal precursor (fibrocytes) origin cannot be excluded. Regardless of their origin, these cells provide further evidence for cellular plasticity and possibly provide an alternative in vitro source of adult neural stem cells.

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  • The development of online learning environments (OLEs) at The University of Auckland Library: collaboration, integration and usability testing

    Zdravkovic, Neda (2013-04-09)

    Conference poster
    The University of Auckland Library

    In order to meet the learning needs of a large number of in-house, flexible learning and distance-learning students from a variety of disciplines, The University of Auckland Library has enhanced the provision of information and academic literacy instruction through the design of online learning environments. Learning Services Librarians, learning designers and subject librarians from The University of Auckland Library have collaborated with faculty, Centre for Academic Development staff, graphic design professionals and web developers to design online courses and tutorials, such as: • Academic Integrity - stand-alone online academic integrity course, compulsory for all new students at the University of Auckland from Semester I 2013; • COMLAW 101: New Zealand’s Legal Framework - curriculum- integrated information literacy online tutorial designed for COMLAW 101: Law in a Business Environment academic course with 2000 students each year; • POPLHLTH 701: Research Methods in Health - curriculum- integrated online information literacy learning environment for postgraduate students completing the POPLHLTH 701: Research Methods in Health course and compulsory assessment activity bearing 15% course mark; • FTVMS 100: Assignment Research Path – curriculum-integrated information literacy online tutorial and compulsory assessment activity (10% course mark) designed for FTVMS 100: Media studies first year undergraduate course with 1000 students each year; • Understanding Your Reading List - generic information literacy online tutorial designed for all first year undergraduate students. The focus of the paper will be on the development framework of online courses, curriculum-integrated and generic tutorials and the analysis of different stages of each project, their collaborative nature and usability testing practices applied (user observation, focus group interviews, surveys) and outcomes. It will introduce CourseBuilder as a web-based tool for the design of online learning environments and activities, its features, functionalities and published outputs. CourseBuilder, developed by the University of Auckland’s Centre for Academic Development, is an authoring tool that provides customisable templates to develop online interactive activities (eg, case studies, reflections and quizzes), import text, insert media, monitor student responses and more. Finally the paper will describe issues and challenges during each development stage, as well as benefits and limitations of using an online learning environment development system.

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  • Registry of BioBricks models using CellML

    Rouilly, Vincent; Canton, Barry; Nielsen, Poul; Kitney, Richard (2007)

    Conference poster
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. One of the main goals in Synthetic Biology is to assess the feasibility of building novel biological systems from interchangeable and standardized parts. In order to collect and share parts, a Registry of standardized DNA BioBricks http://parts.mit.edu/registry has been established at the MIT. BioBricks can be assembled to form devices and systems to operate in living cells. Design of reliable devices and systems would benefit from accurate models of system function. To predict the function of systems built from many parts, we need to have accurate models for the parts and mechanisms to easily compose those part models into a system model. Therefore, in parallel to increasing the number of parts available and characterising them experimentally, a logical extension to the Registry would be to build a Registry of BioBrick models to complement the physical parts.

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  • Space-Time Multi-Resolution Banded Graph-Cut for Fast Segmentation. (Conference Poster)

    Vaudrey, Tobi; Gruber, Daniel; Wedel, Andreas; Klappstein, Jens (2008)

    Conference poster
    The University of Auckland Library

    Conference Details: 30th Annual Symposium of the German Association for Pattern Recognition DAGM Munich, Germany, June 2008. http://www.dagm2008.org/ Applying real-time segmentation is a major issue when processing every frame of image sequences. In this paper, we propose a modi cation of the well known graph-cut algorithm to improve speed for discrete segmentation. Our algorithm yields real-time segmentation, using graph-cut, by performing a single cut on an image with regions of di erent resolutions, combining space-time pyramids and narrow bands. This is especially suitable for image sequences, as segment borders in one image are re ned in the next image. The fast computation time allows one to use information contained in every image frame of an input image stream at 20 Hz, on a standard PC. The algorithm is applied to traf- c scenes, using a monocular camera installed in a moving vehicle. Our results show the segmentation of moving objects with similar results to standard graph-cut, but with improved speed.

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  • Goal: Real-Time Segmentation via Graph Cut Goal: Real-Time Segmentation via Graph Cut

    Vaudrey, Tobi; Wedel, Andreas; Rabe, Clemens; Klappstein, Jens; Klette, Reinhard (2008)

    Conference poster
    The University of Auckland Library

    Conference Details: 2008 23rd International Conference Image and Vision Computing New Zealand. IVCNZ 08. Lincoln University, Christchurch, 26-28 November 2008. http://www.lvl.co.nz/ivcnz2008/ The detection of moving objects is a crucial part of driver assistance systems. This paper tackles this issue using computer vision. Two approaches are investigated, monocular and stereoscopic. The base principals and implementational issues are discussed and detailed, high- lighting areas of concern. In both cases, the detection is based on motion analysis of individually tracked image points (optical ow). The monoc- ular approach relies solely on the optical ow, where as the stereoscopic approach also takes stereo depth information into account. In both ap- proaches the motion analysis provides a motion metric which corresponds to the likelihood that the tracked point is moving. Based on this metric the points are segmented into objects by employing the globally op- timal graph cut algorithm. These approaches are then compared and contrasted using real-world vehicle image sequences.

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  • Benefits of speech & language therapy for hearing impaired children

    Fairgray, Liz; Purdy, Suzanne (2008)

    Conference poster
    The University of Auckland Library

    Conference details: Reflecting Connections 2008, the second conference jointly hosted by the New Zealand Speech-Language Therapists Association and Speech Pathology Australia. Held at the SKYCITY Convention Centre in Auckland, New Zealand, from the 25th to the 29th of May, 2008. http://www.reflectingconnections.co.nz/ Although the need for speech and language therapy is widely recognized for children who are hearing impaired, there is little research evidence for improved outcomes after specific speech and language therapy interventions. With improvements in hearing aid and cochlear implant technology, and consequently improved access to the speech signal, there has been greater emphasis on listening-based therapies. The most widely used therapy is referred to as “auditory-verbal therapy” (AVT). This approach is endorsed by the Alexander Graham Bell Association, but there is paucity of research evidence for AVT effectiveness (Rhoades, 1982; Goldberg & Flexer, 1993; Wray et al., 1997; Rhoades & Chisholm, 2000). Previous studies have focused on psychosocial and educational outcomes of AVT, rather than measuring specific speech and language outcomes. The current study investigates speech and language, speech perception in noise and reading abilities before and after a 6-month period of weekly AVT with an experienced Certified Auditory-Verbal and Speech-language Therapist. Participants are eight children aged 5 to 17 years with moderate-profound sensorineural hearing loss using cochlear implants (CI) and/or hearing aids.

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  • Doped Diamond-Like Carbon (DLC) coated surfaces to reduce fouling from milk

    Patel, Jaiminkumar; Bansal, B; Jones, MI; Hyland, M (2010-11-09)

    Conference poster
    The University of Auckland Library

    In the dairy industry, fouling of processing surfaces is a common and unresolved problem. Surface modification, for example through the application of a surface coating, can alter the surface properties of a material, and may be a potential way to reduce fouling. Typical dairy plant stainless steel surfaces were modified by the deposition of doped Diamond-Like Carbon (DLC) films with varying concentration of doped elements. These modified surfaces were studied for their fouling behavior with milk at both laboratory and pilot scale. None of the doped DLC modified surfaces investigated in the study presented benefits in fouling reduction as compared to unmodified surface.

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  • Three-Dimensional Structural Characterization of Tissue Engineered and Native Ovine Pulmonary Valves

    Eckert, Chad; Gerneke, Dane; LeGrice, IJ; Gottlieb, David; Mayer, JE; Sacks, MS (2009-04)

    Conference poster
    The University of Auckland Library

    OBJECTIVES: Efforts in tissue-engineered heart valves (TEHV) have shown increasingly equivalent mechanical/structural properties compared to native valves, though a literature gap exists regarding detailed structural information. This work was performed to provide such data of implanted TEHV, the native pulmonary valve (PV), and pre-implant scaffold to better understand developing TEHV. METHODS: Dynamically-cultured in vivo samples (“pre-implant”) and ovine TEHV PV in vitro samples (“explant”) were produced based on previous techniques; ovine PVs were excised. Samples were stained with picrosirius red and resinmounted. Using extended-volume scanning laser confocal microscopy (EV-SLCM), 1.5 x 1.5 x 0.4 mm full-thickness samples were imaged at 1 pixel/μm in 1 μm Z-direction steps. Custom software was used to process and visualize samples. Collagen, cell nuclei, and scaffold volume fractions were quantified; scaffold fiber trajectory and length were tracked using custom software. RESULTS: In a scaffold representative volume (90 μm thick), 104 fibers were tracked with a mean fiber length of 137.94 μm 55.4 μm (Fig.1). A comparison between pre-implant and explant samples showed collagen volume fraction increasing from 76.6% to 85.9%, with nuclei and scaffold decreasing from 2.8% to 0.5% and from 5.9% to 0.8%, respectively. With the native collagen volume fraction measured at 70%, pre-implant and explant samples showed an increase in collagen. CONCLUSIONS: This work captured important differences between in vivo/in vitro TEHV constituents; it is the first known work to utilize EV-SLCM on TEHV. A comparison to the native valve showed structural differences that could impact longterm functionality and improve design.

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  • Ciliate Diversity in Stream Biofilms revealed by group-specific PCR primers.

    Dopheide, Andrew; Lear, Gavin; Stott, R; Lewis, Gillian (2008-08-17)

    Conference poster
    The University of Auckland Library

    The ciliates are a diverse protozoan phylum, thought to be of considerable ecological importance in stream ecosystems, including organisms which are abundant and important consumers of bacteria, algae and other protozoa. Understanding of ciliate diversity and ecology is limited, however, particularly in benthic habitats such as stream biofilms. In this study, phylum-specific PCR primers were used in combination with cloning, sequencing and terminal restriction fragment length polymorphism (T-RFLP) analysis to investigate ciliate communities in stream biofilms.

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  • Human Adenovirus ecology in environmental waters in New Zealand

    Dong, Yimin; Lewis, Gillian (2008-08-17)

    Conference poster
    The University of Auckland Library

    A major New Zealand study of pathogen occurrence in surface freshwaters identified occurrence of human adenovirus in 30% of sites and samples by qualitative PCR based methods. The source or nature of these viruses was not clear from the study and raises important questions in both viral ecology and human health protection. The aim of this study was to begin to unravel these questions by (i) development of specific quantitative analysis methods for adenoviruses in water and (ii) to target identifiable groups of adenovirus associated with human respiratory or gastrointestinal infections. These quantitative group specific real time PCR methods were tested in drinking water, recreational water, river water and wastewater. Adenovirus was detected in all primary wastewater samples tested (n=10) at high genome copy number (1.87 x104 to 4.6 x106 per litre) and in 33% (n=15) of the river water and 11% (n=27) of the treated drinking water samples. In addition, adenovirus was detected in 5 of the 6 estuarine recreational water samples (17 to 1190 virus genome copies per litre). DNA sequence analysis suggested that human adenovirus group C (respiratory infection associated) were most commonly associated with river, recreational and drinking water. Group F adenovirus (gastroenteritis associated viruses) were found to dominate in most wastewater (5 - 100 % total adenovirus) but were not detected in surface waters. This study suggests that the ecology of specific groups or types of adenovirus is sufficiently different, external to the host, to have important implications for human health risk assessment.

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  • Effect of light regimes on the utilisation of an exogenous carbon source by freshwater biofilm communities

    Lear, Gavin; Lewis, Gillian (2007-06-23)

    Conference poster
    The University of Auckland Library

    Biofilms are a major source of ‘in stream’ primary production, exhibiting high population density, and being an important source of carbon for microbial heterotrophs. Changing patterns of land-use within freshwater catchment areas may greatly impact on stream biofilm microbial community structure, which in turn may influence the speed and extent with which full ecosystem recovery may occur. This study reports how freshwater biofilm communities respond to additions of acetate, used as a proxy for organic matter, the primary source of carbon within shaded forests and headwater streams. The use of [ 13C] acetate and subsequent isolation of 13C-labelled nucleic acids from the metabolically active fraction of the bacterial community enabled substrate assimilating organisms to be identified. In addition, biofilms were exposed to varied levels of incident light to assess the relative contribution of phototrophic and heterotrophic nutrition.

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  • Ecosystem responses to multiple-stressor gradients: Nutrient and sediment addition to experimental stream channels

    Wagenhoff, A; Matthaei, CD; Lear, Gavin; Lewis, Gillian; Townsend, CR (2009-05-16)

    Conference poster
    The University of Auckland Library

    Agricultural land use can strongly affect stream ecosystems by increasing levels of nutrients and fine sediment cover on the streambed. Knowledge of patterns in ecological responses along gradients of these two stressors will help define thresholds of harm. Leaf breakdown rates, algal and bacterial communities are directly and/or indirectly influenced by nutrient supply and fine sediment cover. To investigate the effects of stressor gradients and their interactions on these biological response parameters, we designed a full-factorial experiment in circular stream-side channels with eight levels each of nutrients (36 to 6900 μg·l-1 DIN, 1.4 to 450 μg·l-1 DRP) and fine sediment (0 to 100 % cover). Algal biomass, bacterial diversity and leaf pack decomposition were determined after three weeks of exposure to both stressors. Algal biomass was significantly higher in channels with lower levels of fine sediment. Bacterial diversity generally increased with increasing nutrient concentrations up to an intermediate nutrient level but then decreased again with the exception of reaching the highest diversity overall at the top nutrient level. Thus, increased levels of nutrients and fine sediment caused major changes to the algal and bacterial communities. In turn, these changes affect other food-web components as well as ecosystem functioning, including decomposition.

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  • Delayed Cerebral Post-arteriole Dilation is Consistent with Observations at Multiple Spatial and Temporal Scales: Evidence from Mathematical Modelling

    Barrett, MJP; Tawhai, MH; Suresh, Vinod (2011-05-25)

    Conference poster
    The University of Auckland Library

    Background and aims: Observations from different neurovascular imaging modalities provide conflicting evidence about the presence and/or extent of volume changes in post-arteriole blood vessels. At the level of individual vessels, two-photon imaging during functional activation shows a rapid increase in arteriolar diameter, but little or no increase in capillaries or venules 1 . In contrast, 'bulk' measurements of flow-volume relationships show large increases in arterial volume 2 , and smaller - but still significant - increases in venous volume 3 . Here, we reconcile these competing observations using a dynamic, biophysically based mathematical model of the hemodynamic response. Methods: We use the widely known Windkessel model that represents blood flow as analogous to electrical current, and networks of blood vessels as analogous to electrical resistances and capacitances. The model also includes a novel description of vascular compliance, viscoelastic effects, and stimulus-driven vasodilation. Experimental observations at progressively more detailed scales are used to constrain and validate the model, following a 'top down' approach. In addition, we test the assumption that post-arteriole vessels do not dilate, and use the model to predict observations at progressively more aggregated scales, following a 'bottom up' approach. Results: Model predictions of the total, arterial, and venous steady state flow-volume relationships agree well with experimental observations, as do predictions of transient changes in flow and volume during functional activation. The model also predicts rapid arteriole dilation during activation. Interestingly, this is accompanied by slow increases in capillary and venule diameter that - for brief stimulation - are near indistinguishable from baseline noise. When assuming no dilation of capillaries or venules, there are only minor differences between the model predictions at the single vessel scale. However, predictions at more aggregated scales are qualitatively and quantitatively different from experimental observations. Conclusions: The model presented here is able to reproduce the main features of experimental observations over a range of spatial and temporal scales. These results suggest that arterial dilation represents the majority of regional cerebral blood volume increases during functional activation, especially during brief stimulation. However, passive dilation in capillaries and venules may be increasingly significant during extended stimulation. This is an important consideration when interpreting or comparing results from neurovascular imaging modalities, such as optical methods and magnetic resonance imaging.

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  • Getting Research 'Out There': ResearchSpace@Auckland

    Newton-Wade, Vanessa; Laurie, John; Hayes, Leonie (2007)

    Conference poster
    The University of Auckland Library

    A key part of the academic research process is publishing the results – ‘getting it out there’. An institutional repository such as ResearchSpace@Auckland provides authors with a channel for near-instantaneous worldwide dissemination of research. ResearchSpace@Auckland has been developed at the University of Auckland under the umbrella of the Institutional Repositories Aotearoa Project (Ira). Built using DSpace Open Source Software, the repository contains ‘research outputs’ from the University of Auckland’s staff and students, including theses, papers and reports. The PhD thesis collection is the flagship of the repository – electronic submission is compulsory for all completing PhD students from 2011. The initial 200 items in the PhD thesis collection were gathered by contacting authors of theses submitted at the University of Auckland since 2001 and inviting them to submit digital copies and consent forms. Trials are underway to digitize theses that are unavailable in digital format. The mandating of compulsory submission for PhD theses submitted at the University of Auckland ensures regulatory requirements for digital deposit are catered for. Other collections for articles, papers, and images are being developed.

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  • The use of whole community bacterial indicators to monitor ecological health, function and variability within stream biofilms

    Lear, Gavin; Boothroyd, IK; Lewis, Gillian (2009-08-30)

    Conference poster
    The University of Auckland Library

    This study describes the extent of variability in biofilm bacterial community structure across a broad range of spatial and temporal scales and assesses whether this may be used as an indicator of stream ecological health and function. A community DNA fingerprinting technique (Automated Ribosomal Intergenic Spacer Analysis - ARISA) was used to examine the structure of bacterial communities within freshwater stream biofilms. When compared with macrobenthic invertebrate community assemblages using multi-dimensional scaling techniques, similar broad-scale trends in population structure were revealed between organisms at these different trophic levels. For both communities, spatial variability in community structure was greater between streams than within each site, or compared to temporal variability measured over 1 year. Distance-based redundancy analysis of both bacterial ARISA and macroinvertebrate data estimated that the largest cause of variation in community structure was due to differences in catchment land-use, rather than any single water quality parameter (e.g. ph or ammoniacal nitrogen). Multidimensional scaling of ARISA data also revealed significant differences in community structure between urban, and less impacted stream sites, providing evidence that whole-bacterial communities could be used as an indicator of freshwater ecological health, analogous to the way that macroinvertebrate communities have been used for many years. In conclusion, we propose the analysis of whole bacterial communities as a cost-effective, high throughput alternative indicator of freshwater ecological health.

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  • Coronary artery bifurcation haemodynamics - comparison between phase contrast MRI and computational fluid dynamics

    Beier, Susann; Ormiston, J; Webster, M; Cater, John; Medrano-Garcia, P; Young, Alistair; Cowan, Brett (2014-01-17)

    Conference poster
    The University of Auckland Library

    Coronary atherosclerosis is common at vessel bifurcations. A quantitative approach to measuring blood velocity, vorticity and more complex flow features at bifurcations would enhance the understanding of the mechanisms of atheroma development, and potentially predict vessels at highest risk. The aim of this work was to validate 4D phase contrast (PC) magnetic resonance imaging flow measurements using a simplified arterial model of the left main coronary bifurcation against computational fluid dynamic (CFD) modelling.

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  • Molecular mechanisms of human T cell differentiation - a role for DNA methylation

    Sheppard, Hilary; Brooks, Anna; Dunbar, PR (2009-09-01)

    Conference poster
    The University of Auckland Library

    The differentiation state of CD8+ T cells is an important determinant of their ability to eradicate tumours and infection; progressive differentiation appears to lead to a decreased upregulated suggesting an indirect mechanism underlie T cell differentiation. Several key cell surface markers are down regulated as differentiation progresses see Fig. 1). We have found that promoter DNA methylation is one mechanism involved in the down regulation of these genes This suggests that manipulation of DNA methylation of key genes could be used to improve the survival and function of CD8+ T cells.

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