1,165 research outputs found

    Identification and characterisation of enteroaggregative Escherichia coli subtypes associated with human disease

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    Enteroaggregative E. coli (EAEC) are a major cause of diarrhoea worldwide. Due to their heterogeneity and carriage in healthy individuals, identification of diagnostic virulence markers for pathogenic strains has been difficult. In this study, we have determined phenotypic and genotypic differences between EAEC strains of sequence types (STs) epidemiologically associated with asymptomatic carriage (ST31) and diarrhoeal disease (ST40). ST40 strains demonstrated significantly enhanced intestinal adherence, biofilm formation, and pro-inflammatory interleukin-8 secretion compared with ST31 isolates. This was independent of whether strains were derived from diarrhoea patients or healthy controls. Whole genome sequencing revealed differences in putative virulence genes encoding aggregative adherence fimbriae, E. coli common pilus, flagellin and EAEC heat-stable enterotoxin 1. Our results indicate that ST40 strains have a higher intrinsic potential of human pathogenesis due to a specific combination of virulence-related factors which promote host cell colonization and inflammation. These findings may contribute to the development of genotypic and/or phenotypic markers for EAEC strains of high virulence

    Clean Agents in Explosion Inerting

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    The US Federal Aviation Administration (FAA) observed during explosion tests that at low concentrations candidate halon replacement agents increased the explosion severity instead of mitigating the event. At UTC Aerospace Systems a test program was developed to assess the behaviour of alternative agents at values below inerting concentration. Two agents were selected, C2HF5 (Pentafluoroethane, HFC-125) and C6F12O (FK-5-1-12, Novec™1230). Baseline tests were performed with unsuppressed C3H8 (propane)/air mixtures and C3H8/air mixtures with CF3Br (Halon 1301) and N2 (nitrogen). Using CF3Br or N2 at below inerting concentrations mitigated the explosion. C2HF5 was tested against C3H8 at stoichiometric (4 vol%) and lower explosion limit (LEL) (2 vol%). Against 4 vol% C3H8 the combustion was mitigated, proportional to agent concentration; however, low concentrations of C2HF5with 2 vol% C3H8 enhanced the explosion. Tests with N2 against a volatile mixture of C3H8 with C2HF5 showed that N2 mitigated the events. Final tests were performed with low concentrations of C6F12O against C3H8/air mixtures. This showed similar behaviour to that observed with the C2HF5 tests. Normally during qualification tests for new agents the stoichiometric concentration of a fuel is deemed to be the worst case scenario and the baseline against which agents are tested. The above described test results show that this assumption may need to be reconsidered. This work shows that contrary to common assumption the agents investigated did not act chemically at the flame front, but mainly cooled the flame and changed the stoichiometry, i.e. the ratio of components of the flammable mixture

    Use of whole-genus genome sequence data to develop a multilocus sequence typing tool that accurately identifies Yersinia isolates to the species and subspecies levels

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    The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus. Here we report the mining of this enormous data set to create a multilocus sequence typing-based scheme that can identify Yersinia strains to the species level to a level of resolution equal to that for whole-genome sequencing. Our assay is designed to be able to accurately subtype the important human-pathogenic species Yersinia enterocolitica to whole-genome resolution levels. We also report the validation of the scheme on 386 strains from reference laboratory collections across Europe. We propose that the scheme is an important molecular typing system to allow accurate and reproducible identification of Yersinia isolates to the species level, a process often inconsistent in nonspecialist laboratories. Additionally, our assay is the most phylogenetically informative typing scheme available for Y. enterocolitica

    Little Black Me : Song & Refrain

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    https://digitalcommons.library.umaine.edu/mmb-vp/3255/thumbnail.jp

    Madeline

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    https://digitalcommons.library.umaine.edu/mmb-vp/2058/thumbnail.jp

    Sweet Irish Rose

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    Illustration of two homes; Illustration of large rose above homeshttps://scholarsjunction.msstate.edu/cht-sheet-music/7693/thumbnail.jp

    Pals, Good Old Pals

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    https://digitalcommons.library.umaine.edu/mmb-vp/3817/thumbnail.jp

    Can\u27t You Take It Back, And Change It For A Boy?

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    https://digitalcommons.library.umaine.edu/mmb-vp/5826/thumbnail.jp

    I\u27ve Grown So Used To You

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    https://digitalcommons.library.umaine.edu/mmb-vp/5503/thumbnail.jp
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