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Search Results: 1 - 10 of 9669 matches for " Sara-Jane Dunn "
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Computational Models Reveal a Passive Mechanism for Cell Migration in the Crypt
Sara-Jane Dunn, Inke S. N?thke, James M. Osborne
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080516
Abstract: Cell migration in the intestinal crypt is essential for the regular renewal of the epithelium, and the continued upward movement of cells is a key characteristic of healthy crypt dynamics. However, the driving force behind this migration is unknown. Possibilities include mitotic pressure, active movement driven by motility cues, or negative pressure arising from cell loss at the crypt collar. It is possible that a combination of factors together coordinate migration. Here, three different computational models are used to provide insight into the mechanisms that underpin cell movement in the crypt, by examining the consequence of eliminating cell division on cell movement. Computational simulations agree with existing experimental results, confirming that migration can continue in the absence of mitosis. Importantly, however, simulations allow us to infer mechanisms that are sufficient to generate cell movement, which is not possible through experimental observation alone. The results produced by the three models agree and suggest that cell loss due to apoptosis and extrusion at the crypt collar relieves cell compression below, allowing cells to expand and move upwards. This finding suggests that future experiments should focus on the role of apoptosis and cell extrusion in controlling cell migration in the crypt.
A Two-Dimensional Model of the Colonic Crypt Accounting for the Role of the Basement Membrane and Pericryptal Fibroblast Sheath
Sara-Jane Dunn ,Paul L. Appleton,Scott A. Nelson,Inke S. N?thke,David J. Gavaghan,James M. Osborne
PLOS Computational Biology , 2012, DOI: 10.1371/journal.pcbi.1002515
Abstract: The role of the basement membrane is vital in maintaining the integrity and structure of an epithelial layer, acting as both a mechanical support and forming the physical interface between epithelial cells and the surrounding connective tissue. The function of this membrane is explored here in the context of the epithelial monolayer that lines the colonic crypt, test-tube shaped invaginations that punctuate the lining of the intestine and coordinate a regular turnover of cells to replenish the epithelial layer every few days. To investigate the consequence of genetic mutations that perturb the system dynamics and can lead to colorectal cancer, it must be possible to track the emerging tissue level changes that arise in the crypt. To that end, a theoretical crypt model with a realistic, deformable geometry is required. A new discrete crypt model is presented, which focuses on the interaction between cell- and tissue-level behaviour, while incorporating key subcellular components. The model contains a novel description of the role of the surrounding tissue and musculature, based upon experimental observations of the tissue structure of the crypt, which are also reported. A two-dimensional (2D) cross-sectional geometry is considered, and the shape of the crypt is allowed to evolve and deform. Simulation results reveal how the shape of the crypt may contribute mechanically to the asymmetric division events typically associated with the stem cells at the base. The model predicts that epithelial cell migration may arise due to feedback between cell loss at the crypt collar and density-dependent cell division, an hypothesis which can be investigated in a wet lab. This work forms the basis for investigation of the deformation of the crypt structure that can occur due to proliferation of cells exhibiting mutant phenotypes, experiments that would not be possible in vivo or in vitro.
"Eigentlich war ich der Star": Attributionsmanagement in Gespr chen "Actually I Was the Star": Managing Attributions in Conversation "Realmente fui la estrella": manejando las atribuciones en la conversación
Sara-Jane Finlay,Guy Faulkner
Forum : Qualitative Social Research , 2003,
Abstract: In diesem Beitrag skizzieren wir die Eckdaten eines diskursiven Ansatzes zur Untersuchung von Attributionen in der Sportpsychologie. Attributionstheoretische Ans tze spielen in der Sportpsychologie traditionell eine wichtige Rolle. Attributionen werden hierbei als die wahrgenommenen Ursachen oder Konsequenzen verstanden, die Menschen einem Ereignis zuschreiben. Ein besonders einflussreiches, in der p dagogischen Psychologie entwickeltes Attributionsmodell erfordert die dimensionale Kategorisierung von Attributionen (z.B. internal-external, stabil-nicht stabil, kontrolllierbar-nicht kontrollierbar), die in der Sportpsychologie fast ausschlie lich mittels Frageb gen erfasst werden (und dies zumeist im Rahmen einer sehr eingeschr nkten theoretischen Perspektive). Im Unterschied hierzu werden im diskursiven Ansatz Gespr che eingesetzt bzw. analysiert, dies aber nicht zur Erfassung internaler oder dimensionaler Kategorien, sondern das Gespr ch selbst ist Gegenstand des Interesses. Im vorliegenden Beitrag setzen wir uns – rückgreifend auf Prinzipien der Konversationsanalyse – kritisch mit der traditionellen Konzeptualisierung und Erforschung von Attributionen auseinander. An empirischen Gespr chsbeispielen mit Sportler(innen) verdeutlichen wir dann unser Verst ndnis von Attributionen als "talk-in-action" statt einem Ansatz, der Attributionen als blo e Aufeinanderfolge diskreter kognitiver Elemente und Dimensionen zu erforschen versucht. Wie Attributionsprozesse in Gespr chen verlaufen, veranschaulichen wir an drei Bereichen: an Fragen nach Niederlagen, am "bescheidenen Reden" über Siege, und an der Flüchtigkeit und schweren Greifbarkeit von Attributionen im Gespr chsverlauf. Abschlie end werden Implikationen eines diskursiven Ansatzes für die sportpsychologische Untersuchung von Attributionen diskutiert. URN: urn:nbn:de:0114-fqs030133 In this paper, we outline the parameters of a discursive approach to attributions in sport psychology. Attribution theory has had a strong presence within sport and exercise psychology. Attributions are the perceived causes or reasons that people give for an occurrence related to themselves or others. An attributional model, developed in educational psychology, has been most influential and often requires the researcher(s) or participants to determine the dimensional categorisation of attributions (e.g., internal-external, stable-unstable, controllable-uncontrollable). Assessing attributions in sport and exercise psychology has been almost exclusively through self-report questionnaires and entrenched within a limited theoretical
"Harte" oder "weiche" Suche? Manuelle vs. elektronische Suchstrategien in der Medienforschung Hard or Soft Searching? Electronic Database Versus Hand Searching in Media Research Búsqueda rigurosa o blanda? La búsqueda electrónica en base de datos versus la búsqueda manual en la investigación de los medios
Stephannie C. Roy,Guy Faulkner,Sara-Jane Finlay
Forum : Qualitative Social Research , 2007,
Abstract: Für qualitative Medienforschung ist es wesentlich, die Bedeutung ihrer Forschungsfrage für Samplingstrategien und die folgende Datenerhebung zu beachten. Wir illustrieren dies an Erfahrungen, die wir im Zuge der Auswahl einer Methodik zum Sammeln von Artikeln zu physischer Aktivit t aus der Tagespresse gewonnen haben. Wir reflektieren die Konsequenzen von spezifischen Suchstrategien für unser Sampling, also von manueller Suche einerseits und elektronischer Suche andererseits und betonen in diesem Zusammenhang die unterschiedlichen Konsequenzen, die hieraus für die Reliabilit t der Ergebnisse erwachsen. Forschende sollten sich der Vor- und Nachteile, die mit solchen Entscheidungen einhergehen, bewusst sein bis hin zu der Frage, welche Informationen jeweils verfügbar sind mit folgenden Konsequenzen für die eigentliche Forschungsarbeit. Wir schlie en, indem wir die Bedeutsamkeit dieser überlegungen für die Reliabilit t einer Inhaltsanalyse veranschaulichen. URN: urn:nbn:de:0114-fqs0703204 It is important for qualitative media researchers to consider the impact of their research objectives on the sample frame imposed and subsequent data-collection methods. To illustrate this, we present some of the issues we encountered in determining a method of gathering physical activity articles in daily newspapers. We consider the implications of search choices for our sample, highlight the impact of using hardcopy hand-searches and electronic indexes and emphasise the importance of conducting a study to determine the reliability of hand-searching versus electronic index search methods. We suggest that researchers should be aware of the benefits and drawbacks of search methods including what kinds of information these methods yield and the possible effects on the research project. We conclude by highlighting the importance of these discussions to the reliability of content analysis. URN: urn:nbn:de:0114-fqs0703204 Es importante que los investigadores cualitativos de medios consideren el impacto de sus objetivos de investigación sobre el marco muestral impuesto y sobre los métodos de recolección de datos. Para ilustrar esto, presentamos algunos de los temas con los que tropezamos para determinar el método de búsqueda de artículos sobre la actividad física en los diarios. Consideramos las implicaciones de las elecciones de búsqueda para nuestra muestra, destacando el impacto de la realización manual de búsquedas de copia impresa y el uso de índices electrónicos, y enfatizamos la importancia de estudiar la fiabilidad de los métodos de búsqueda de manual versus electrónica
Ten Simple Rules for Effective Computational Research
James M. Osborne ,Miguel O. Bernabeu,Maria Bruna,Ben Calderhead,Jonathan Cooper,Neil Dalchau,Sara-Jane Dunn,Alexander G. Fletcher,Robin Freeman,Derek Groen,Bernhard Knapp,Greg J. McInerny,Gary R. Mirams,Joe Pitt-Francis,Biswa Sengupta,David W. Wright,Christian A. Yates,David J. Gavaghan,Stephen Emmott,Charlotte Deane
PLOS Computational Biology , 2014, DOI: doi/10.1371/journal.pcbi.1003506
Abstract:
Chaste: An Open Source C++ Library for Computational Physiology and Biology
Gary R. Mirams ,Christopher J. Arthurs,Miguel O. Bernabeu,Rafel Bordas,Jonathan Cooper,Alberto Corrias,Yohan Davit,Sara-Jane Dunn,Alexander G. Fletcher,Daniel G. Harvey,Megan E. Marsh,James M. Osborne,Pras Pathmanathan,Joe Pitt-Francis,James Southern,Nejib Zemzemi,David J. Gavaghan
PLOS Computational Biology , 2013, DOI: 10.1371/journal.pcbi.1002970
Abstract: Chaste — Cancer, Heart And Soft Tissue Environment — is an open source C++ library for the computational simulation of mathematical models developed for physiology and biology. Code development has been driven by two initial applications: cardiac electrophysiology and cancer development. A large number of cardiac electrophysiology studies have been enabled and performed, including high-performance computational investigations of defibrillation on realistic human cardiac geometries. New models for the initiation and growth of tumours have been developed. In particular, cell-based simulations have provided novel insight into the role of stem cells in the colorectal crypt. Chaste is constantly evolving and is now being applied to a far wider range of problems. The code provides modules for handling common scientific computing components, such as meshes and solvers for ordinary and partial differential equations (ODEs/PDEs). Re-use of these components avoids the need for researchers to ‘re-invent the wheel’ with each new project, accelerating the rate of progress in new applications. Chaste is developed using industrially-derived techniques, in particular test-driven development, to ensure code quality, re-use and reliability. In this article we provide examples that illustrate the types of problems Chaste can be used to solve, which can be run on a desktop computer. We highlight some scientific studies that have used or are using Chaste, and the insights they have provided. The source code, both for specific releases and the development version, is available to download under an open source Berkeley Software Distribution (BSD) licence at http://www.cs.ox.ac.uk/chaste, together with details of a mailing list and links to documentation and tutorials.
Central venous catheter-related bacteremia caused by Kocuria kristinae: Case report and review of the literature
Ryan Dunn, Sara Bares, Michael Z David
Annals of Clinical Microbiology and Antimicrobials , 2011, DOI: 10.1186/1476-0711-10-31
Abstract: Kocuria species are ubiquitous in the environment and part of normal skin and oral flora of humans and other mammals [1]. They are, however, uncommon human pathogens with only a limited number of cases reported in the literature. K. kristinae is a facultative anaerobic bacterium that is a non-motile, catalase-positive, coagulase-negative, gram- positive coccus that occurs in tetrads. It has been previously reported to cause bacteremia in chronically ill patients with malignancies or other immunosuppressed states [2-4]. K. kristinae has been associated with one case of cholecystitis [5]. Recently, it has been associated with two cases of peritonitis related to peritoneal dialysis [6,7]. To the best of our knowledge we present here the first reported case of K. kristinae bacteremia in a pregnant, but otherwise healthy adult female.In August 2010, a 29-year-old African American female who was 16 weeks pregnant presented to her primary care physician complaining of a fever of 103 degrees Fahrenheit, chills, pleuritic chest pain, shortness of breath and a non-productive cough for 2 days. Her pregnancy had been complicated by thyrotoxicosis and hyperemesis gravidarum requiring the placement of a peripherally inserted central venous catheter for total parenteral nutrition (TPN). The catheter had been placed approximately 11 days prior to the onset of her symptoms and she had received TPN since that time. The patient had no other significant medical history and was born in the United States with no recent travel or unusual food exposures. She did not smoke tobacco, drink alcohol or use illicit drugs. She was sexually active with a single male partner and had no history of sexually transmitted diseases. Her only sick contact was her father who had recently been treated for cellulitis. Her immunization history was unknown.The patient was initially given a 5-day course of azithromycin. No laboratory studies or cultures were performed at the time. Three days later she returned
Partitioning the Proteome: Phase Separation for Targeted Analysis of Membrane Proteins in Human Post-Mortem Brain
Jane A. English, Bruno Manadas, Caitriona Scaife, David R. Cotter, Michael J. Dunn
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039509
Abstract: Neuroproteomics is a powerful platform for targeted and hypothesis driven research, providing comprehensive insights into cellular and sub-cellular disease states, Gene × Environmental effects, and cellular response to medication effects in human, animal, and cell culture models. Analysis of sub-proteomes is becoming increasingly important in clinical proteomics, enriching for otherwise undetectable proteins that are possible markers for disease. Membrane proteins are one such sub-proteome class that merit in-depth targeted analysis, particularly in psychiatric disorders. As membrane proteins are notoriously difficult to analyse using traditional proteomics methods, we evaluate a paradigm to enrich for and study membrane proteins from human post-mortem brain tissue. This is the first study to extensively characterise the integral trans-membrane spanning proteins present in human brain. Using Triton X-114 phase separation and LC-MS/MS analysis, we enriched for and identified 494 membrane proteins, with 194 trans-membrane helices present, ranging from 1 to 21 helices per protein. Isolated proteins included glutamate receptors, G proteins, voltage gated and calcium channels, synaptic proteins, and myelin proteins, all of which warrant quantitative proteomic investigation in psychiatric and neurological disorders. Overall, our sub-proteome analysis reduced sample complexity and enriched for integral membrane proteins by 2.3 fold, thus allowing for more manageable, reproducible, and targeted proteomics in case vs. control biomarker studies. This study provides a valuable reference for future neuroproteomic investigations of membrane proteins, and validates the use Triton X-114 detergent phase extraction on human post mortem brain.
Beating the blues after Cancer: randomised controlled trial of a tele-based psychological intervention for high distress patients and carers
Suzanne K Chambers, Afaf Girgis, Stefano Occhipinti, Sandy Hutchison, Jane Turner, Rob Carter, Jeff Dunn
BMC Cancer , 2009, DOI: 10.1186/1471-2407-9-189
Abstract: 140 patients and 140 carers per condition (560 participants in total) will been recruited after being identified as high distress through caller screening at two community-based cancer helplines and randomised to 1) a single 30-minute telephone support and education session with a nurse counsellor with self management materials 2) a tele-based psychologist delivered five session individualised cognitive behavioural intervention. Session components will include stress reduction, problem-solving, cognitive challenging and enhancing relationship support and will be delivered weekly. Participants will be assessed at baseline and 3, 6 and 12 months after recruitment. Outcome measures include: anxiety and depression, cancer specific distress, unmet psychological supportive care needs, positive adjustment, overall Quality of life.The study will provide recommendations about the efficacy and potential economic value of minimal contact self management vs. tele-based psychologist delivered cognitive behavioural intervention to facilitate better psychosocial adjustment and mental health for people with cancer and their carers.ACTRN12609000301268.It is estimated that from 2001 to 2011 the number of newly diagnosed cases of cancer will increase by 29% in women and 32% in men [1]. Cancer is the leading cause of burden of disease and injury in Australia, accounting for nearly one-fifth of the total disease burden [2]. The diagnosis and subsequent treatment of cancer is a major life stress that is followed by a range of well described psychological, social, physical and spiritual difficulties [3]. While over time most people diagnosed with cancer go on to adjust effectively to their changed life circumstances without clinical intervention, approximately 35% will experience persistent clinically significant distress such as anxiety and depression, adjustment disorders, fears about cancer recurrence, and post traumatic stress reactions, that for some will worsen over time [4,5]. As w
Too big to be noticed: cryptic invasion of Asian camel crickets in North American houses
Mary Jane Epps,Holly L. Menninger,Nathan LaSala,Robert R. Dunn
PeerJ , 2015, DOI: 10.7717/peerj.523
Abstract: Despite the rapid expansion of the built environment, we know little about the biology of species living in human-constructed habitats. Camel crickets (Rhaphidophoridae) are commonly observed in North American houses and include a range of native taxa as well as the Asian Diestrammena asynamora (Adelung), a species occasionally reported from houses though considered to be established only in greenhouses. We launched a continental-scale citizen science campaign to better understand the relative distributions and frequency of native and nonnative camel crickets in human homes across North America. Participants contributed survey data about the presence or absence of camel crickets in homes, as well as photographs and specimens of camel crickets allowing us to identify the major genera and/or species in and around houses. Together, these data offer insight into the geographical distribution of camel crickets as a presence in homes, as well as the relative frequency and distribution of native and nonnative camel crickets encountered in houses. In so doing, we show that the exotic Diestrammena asynamora not only has become a common presence in eastern houses, but is found in these environments far more frequently than native camel crickets. Supplemental pitfall trapping along transects in 10 urban yards in Raleigh, NC revealed that D. asynamora can be extremely abundant locally around some homes, with as many as 52 individuals collected from pitfalls in a single yard over two days of sampling. The number of D. asynamora individuals present in a trap was negatively correlated with the trap’s distance from a house, suggesting that these insects may be preferentially associated with houses but also are present outside. In addition, we report the establishment in the northeastern United States of a second exotic species, putatively Diestrammena japanica Blatchley, which was previously undocumented in the literature. Our results offer new insight into the relative frequency and distribution of camel crickets living in human homes, and emphasize the importance of the built environment as habitat for two little-known invading species of Orthoptera.
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