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Search Results: 1 - 10 of 8708 matches for " Geraint Brian Osborne "
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Robert M. Emerson, Rachel I. Fretz, and Linda L. Shaw, Writing Ethnographic Fieldnotes
Geraint Brian Osborne
The Canadian Journal of Sociology , 2012,
Abstract: Book Review
Transcriptional Priming of Salmonella Pathogenicity Island-2 Precedes Cellular Invasion
Suzanne E. Osborne, Brian K. Coombes
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021648
Abstract: Invasive salmonellosis caused by Salmonella enterica involves an enteric stage of infection where the bacteria colonize mucosal epithelial cells, followed by systemic infection with intracellular replication in immune cells. The type III secretion system encoded in Salmonella Pathogenicity Island (SPI)-2 is essential for intracellular replication and the regulators governing high-level expression of SPI-2 genes within the macrophage phagosome and in inducing media thought to mimic this environment have been well characterized. However, low-level expression of SPI-2 genes is detectable in media thought to mimic the extracellular environment suggesting that additional regulatory pathways are involved in SPI-2 gene expression prior to cellular invasion. The regulators involved in this activity are not known and the extracellular transcriptional activity of the entire SPI-2 island in vivo has not been studied. We show that low-level, SsrB-independent promoter activity for the ssrA-ssrB two-component regulatory system and the ssaG structural operon encoded in SPI-2 is dependent on transcriptional input by OmpR and Fis under non-inducing conditions. Monitoring the activity of all SPI-2 promoters in real-time following oral infection of mice revealed invasion-independent transcriptional activity of the SPI2 T3SS in the lumen of the gut, which we suggest is a priming activity with functional relevance for the subsequent intracellular host-pathogen interaction.
RpoE fine tunes expression of a subset of SsrB-regulated virulence factors in Salmonella enterica serovar Typhimurium
Suzanne E Osborne, Brian K Coombes
BMC Microbiology , 2009, DOI: 10.1186/1471-2180-9-45
Abstract: In this study we demonstrate that RpoE is involved in fine-tuning the expression of a subset of SsrB-regulated genes found in the Salmonella pathogenicity island-2 (SPI-2) genetic locus that encodes a horizontally acquired type III secretion system, and unlinked genes integrated into this regulon that are required for virulence in host animals.These data point to a potential connection between the virulence phenotype of strains lacking ssrB and rpoE, and highlight new transcriptional regulation that might be essential for appropriate temporal and spatial control of the virulence-associated type III secretion system during host infection.Salmonella enterica are enteric pathogens that acquired a type III secretion system (T3SS) through horizontal gene transfer of a genomic island termed Salmonella Pathogenicity Island 2 (SPI-2) [1,2]. The SPI-2-encoded T3SS and its translocated effectors modify the intracellular host niche for Salmonella replication [3-5]. SPI-2 also has genes, ssrA and ssrB, which code for SsrAB, a two-component regulatory system needed for expression of the T3SS [6,7]. SsrB regulates the expression of SPI-2 encoded substrate effectors including ssaB, as well as several integrated virulence effectors such as sseL [8] and srfN [9] that are encoded elsewhere on the chromosome but that have integrated into the SsrB regulon. Mutants lacking ssrAB are unable to survive within macrophages and are avirulent in mice [1].Alternative sigma factors coordinate gene expression in response to environmental cues sensed by the bacterium. Sigma factors have a specific recognition motif at the -35 and -10 positions and function to concentrate RNA polymerase at a subset of promoters [10]. One alternative sigma factor, RpoE (σE) responds to envelope stress at the cell surface. Release of σE from its inner membrane anchored anti-sigma factor, RseA, leads to induction of genes required to maintain cell envelope integrity [11]. SsrB-regulated translocated effectors protect
Introduction to Forensic Dentistry Continuing Education Course  [PDF]
Diane Osborne
Forensic Medicine and Anatomy Research (FMAR) , 2013,
Abstract: This course is an introduction to the basics of forensic dentistry beginning with its historical origins to modern advancements. After an introduction to basic principles, application of this information will be demonstrated in current cases, training in mass fatalities and participation in a mass fatality workshop scenario using dry skull remains. Time permitting, a tour of the Las Vegas Coroner’s Office will be available.
Gene functional similarity search tool (GFSST)
Peisen Zhang, Jinghui Zhang, Huitao Sheng, James J Russo, Brian Osborne, Kenneth Buetow
BMC Bioinformatics , 2006, DOI: 10.1186/1471-2105-7-135
Abstract: By using a statistical model to measure the functional similarity of genes based on the Gene Ontology directed acyclic graph, we developed a novel Gene Functional Similarity Search Tool (GFSST) to identify genes with related functions from annotated proteome databases. This search engine lets users design their search targets by gene functions.An implementation of GFSST which works on the UniProt (Universal Protein Resource) for the human and mouse proteomes is available at GFSST Web Server. GFSST provides functions not only for similar gene retrieval but also for gene search by one or more GO terms. This represents a powerful new approach for selecting similar genes and gene products from proteome databases according to their functions.Cellular function in a biological system normally involves participation and interaction of multiple genes. Mutations that alter function of any one of these genes can potentially increase disease susceptibility. For example, the tumor suppressor gene BRCA1 suppresses cell growth and participates in transcription-coupled DNA damage repair. Mutations in BRCA1 increase the risk of early onset breast cancer as well as ovarian and prostate cancer [[1,2], and [3]]. Genes with functions similar to BRCA1 can be considered additional candidate genetic risk factors for breast, ovarian, prostate, or other cancers.One common approach to identify functionally similar genes is to find genes that share significant sequence homology. However, functional similarity does not always require sequence similarity. For example, both P53 [4] and BRCA1 [5] function as tumor suppressor genes. Similar to BRCA1, mutations in P53 have also been found in breast cancer patients [6]. The two genes share no sequence homology. As a result, a sequence similarity search tool, such as BLAST [7], is unable to reveal their functional similarity.An alternative to sequence homology search is key word search, but this approach has two weaknesses. First, key words for gene f
Prognostic significance of new onset ascites in patients with pancreatic cancer
Emmanuel E Zervos, Dana Osborne, Brian A Boe, German Luzardo, Steven B Goldin, Alexander S Rosemurgy
World Journal of Surgical Oncology , 2006, DOI: 10.1186/1477-7819-4-16
Abstract: A prospective database was queried to identify patients with pancreatic cancer who develop ascites. Stage at presentation, size, and location of primary tumor, treatment received and length of survival after onset of ascites were determined.A total of 15 patients were identified. Of which 4 patients (1 stage II, 3 stage III) underwent pancreaticoduodenectomy and manifested with ascites 2, 3, 24 and 47 months after surgery (tumor size 2.9 ± 1.32 cm). All but one of the remaining 11 patients (tumor size 4.4 ± 3.38 cm) presented with metastatic disease, and all developed malignant ascites 9 months after diagnosis, dying 2 months later. Resected patients lived longer before the onset of ascites, but not after.Once diagnosed, ascites in pancreatic cancer patients heralds imminent death. Limited survival should be considered when determining the aggressiveness of further intervention.Pancreatic cancer is the 5th most common gastrointestinal (GI) malignancy but the third most common cause of death among all GI cancers [1]. Almost all patients with pancreatic cancer ultimately die of it, usually within 6 months of diagnosis [2]. The vast majority of these patients are ineligible for surgical therapy at the time of diagnosis due to metastatic spread or local invasion and death usually occurs by inanition rather than gross tumor burden. Aggressive chemotherapeutic regimens are generally highly toxic and prolong life by weeks, rather than months [3]. Most patients with unresectable pancreatic cancer die of their disease before completing a standard course of therapy.Common manifestations of end stage pancreatic cancer include: gastric outlet obstruction due to tumor ingrowth to the duodenum, cachexia, deep venous thrombosis (Trousseau's phenomenon), anasarca and ascites. Ascites manifests in only 20% of pancreatic cancer patients and its cause is multifactorial [4]. It can occur due to obstruction of diaphragmatic lymphatics, increased production of exudate by the tumor itself
Revising the Economic Imperative for US STEM Education
Brian M. Donovan ,David Moreno Mateos,Jonathan F. Osborne,Daniel J. Bisaccio
PLOS Biology , 2014, DOI: 10.1371/journal.pbio.1001760
Abstract: Summary Over the last decade macroeconomic studies have established a clear link between student achievement on science and math tests and per capita gross domestic product (GDP) growth, supporting the widely held belief that science, technology, engineering, and math (STEM) education are important factors in the production of economic prosperity. We critique studies that use science and math tests to predict GDP growth, arguing that estimates of the future economic value of STEM education involve substantial speculation because they ignore the impacts of economic growth on biodiversity and ecosystem functionality, which, in the long-term, limit the potential for future economic growth. Furthermore, we argue that such ecological impacts can be enabled by STEM education. Therefore, we contend that the real economic imperative for the STEM pipeline is not just raising standardized test scores, but also empowering students to assess, preserve, and restore ecosystems in order to reduce ecological degradation and increase economic welfare.
Optimal Educational Investment: Domestic Equity and International Competition
Geraint Johnes
ISRN Economics , 2012, DOI: 10.5402/2012/909727
Optimal Educational Investment: Domestic Equity and International Competition
Geraint Johnes
ISRN Economics , 2012, DOI: 10.5402/2012/909727
Abstract: We construct a family of models to analyse the effect on optimal educational investment of (i) society's preferences for equity and (ii) competition between countries. The models provide insights about the impact of a variety of parameters on optimal policy. In particular, we identify a form of “overeducation” that is new to the literature and provide a counterexample to a common finding in the literature on fiscal federalism. 1. Introduction Economists’ interest in education often focuses upon the rate of return to schooling investments. Yet it is a characteristic of the education system in many countries that, for the most part, schooling is funded out of the public purse. While one might imagine that governments should seek to “equalise rates of return in all directions” [1], it is often the case that the authorities have broader objectives that inform their educational investments. For example, a government may have preferences about equity as well as efficiency. Or it may, for various reasons, be concerned to ensure that its own investment in its people’s skills does not fall behind investments made by other countries. We examine these issues by developing, in the next section, a series of models that can aid our understanding of how, under a variety of conditions, the optimal provision of publicly funded education is determined. 2. The Model In this section we present a family of related models of education and the tax system in order to provide insights into how governments can reach decisions about the optimal funding of education where (i) society has preferences about equity and (ii) decisions have impacts across countries. The basic structure of the model builds on the analysis of Johnes [2]. 2.1. Equity Suppose that the disposable income of individual is given by where is a basic income to be defined more precisely later, is a binary variable that indicates whether the th individual has undertaken schooling or not, is the proportional rate of income tax, and is the income premium associated with schooling. Both and are assumed exogenous. Tax revenues are used solely for the purpose of financing education which, we assume, takes place instantaneously. This distinguishes the model from a family of models typified by that of Bovenberg and Jacobs [3], where taxation also serves a redistributive purpose. In our model we keep the tax system simple in order to facilitate the extension to the international case in Section 2.2 below. In the present model, tax revenues fund education as a means of achieving the redistribution of income, but they could
Optical Synthesis of Terahertz and Millimeter-Wave Frequencies with Discrete Mode Diode Lasers
Stephen O'Brien,Simon Osborne,David Bitauld,Nicola Brandonisio,Andreas Amann,Richard Phelan,Brian Kelly,James O'Gorman
Physics , 2010, DOI: 10.1109/TMTT.2010.2074931
Abstract: It is shown that optical synthesis of terahertz and millimeter-wave frequencies can be achieved using two-mode and mode-locked discrete mode diode lasers. These edge-emitting devices incorporate a spatially varying refractive index profile which is designed according to the spectral output desired of the laser. We first demonstrate a device which supports two primary modes simultaneously with high spectral purity. In this case sinusoidal modulation of the optical intensity at terahertz frequencies can be obtained. Cross saturation of the material gain in quantum well lasers prevents simultaneous lasing of two modes with spacings in the millimeter-wave region. We show finally that by mode-locking of devices that are designed to support a minimal set of four primary modes, we obtain a sinusoidal modulation of the optical intensity in this frequency region.
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