246 research outputs found

    Depth dependent magnetization profiles of hybrid exchange springs

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    We report on the magnetization depth profile of a hybrid exchange spring system in which a Co/Pd multilayer with perpendicular anisotropy is coupled to a CoFeB thin film with in-plane anisotropy. The competition between these two orthogonal anisotropies promotes a strong depth dependence of the magnetization orientation. The angle of the magnetization vector is sensitive both to the strength of the individual anisotropies and to the local exchange constant, and is thus tunable by changing the thickness of the CoFeB layer and by substituting Ni for Pd in one layer of the Co/Pd stack. The resulting magnetic depth profiles are directly probed by element specific x-ray magnetic circular dichroism (XMCD) of the Co, Fe, and Ni layers located at different average depths. The experimental results are corroborated by micromagnetic simulations

    Genomic analysis of the function of the transcription factor gata3 during development of the Mammalian inner ear

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    We have studied the function of the zinc finger transcription factor gata3 in auditory system development by analysing temporal profiles of gene expression during differentiation of conditionally immortal cell lines derived to model specific auditory cell types and developmental stages. We tested and applied a novel probabilistic method called the gamma Model for Oligonucleotide Signals to analyse hybridization signals from Affymetrix oligonucleotide arrays. Expression levels estimated by this method correlated closely (p<0.0001) across a 10-fold range with those measured by quantitative RT-PCR for a sample of 61 different genes. In an unbiased list of 26 genes whose temporal profiles clustered most closely with that of gata3 in all cell lines, 10 were linked to Insulin-like Growth Factor signalling, including the serine/threonine kinase Akt/PKB. Knock-down of gata3 in vitro was associated with a decrease in expression of genes linked to IGF-signalling, including IGF1, IGF2 and several IGF-binding proteins. It also led to a small decrease in protein levels of the serine-threonine kinase Akt2/PKB beta, a dramatic increase in Akt1/PKB alpha protein and relocation of Akt1/PKB alpha from the nucleus to the cytoplasm. The cyclin-dependent kinase inhibitor p27(kip1), a known target of PKB/Akt, simultaneously decreased. In heterozygous gata3 null mice the expression of gata3 correlated with high levels of activated Akt/PKB. This functional relationship could explain the diverse function of gata3 during development, the hearing loss associated with gata3 heterozygous null mice and the broader symptoms of human patients with Hearing-Deafness-Renal anomaly syndrome

    Integrating whole-genome sequencing within the National Antimicrobial Resistance Surveillance Program in the Philippines

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    Funding: This work was funded by the Newton Fund, Medical Research Council (UK) grant MR/N019296/1, Philippine Council for Health Research and Development project number FP160007. J.S. was partially supported by research grants RR025040 and U01CA207167 from the National Institutes of Health (NIH). S.A. and D.M.A. were additionally supported by the National Institute for Health Research (UK) Global Health Research Unit on genomic Surveillance of AMR(16_136_111) and by the Centre for Genomic Pathogen Surveillance (http://pathogensurveillance.net).National networks of laboratory-based surveillance of antimicrobial resistance (AMR) monitor resistance trends and disseminate these data to AMR stakeholders. Whole-genome sequencing (WGS) can support surveillance by pinpointing resistance mechanisms and uncovering transmission patterns. However, genomic surveillance is rare in low- and middle-income countries. Here, we implement WGS within the established Antimicrobial Resistance Surveillance Program of the Philippines via a binational collaboration. In parallel, we characterize bacterial populations of key bug-drug combinations via a retrospective sequencing survey. By linking the resistance phenotypes to genomic data, we reveal the interplay of genetic lineages (strains), AMR mechanisms, and AMR vehicles underlying the expansion of specific resistance phenotypes that coincide with the growing carbapenem resistance rates observed since 2010. Our results enhance our understanding of the drivers of carbapenem resistance in the Philippines, while also serving as the genetic background to contextualize ongoing local prospective surveillance.Publisher PDFPeer reviewe

    Francisella tularensis Elicits IL-10 via a PGE2-Inducible Factor, to Drive Macrophage MARCH1 Expression and Class II Down-Regulation

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    Francisella tularensis is a bacterial pathogen that uses host-derived PGE2 to subvert the host's adaptive immune responses in multiple ways. Francisella-induced PGE2 acts directly on CD4 T cells to blunt production of IFN-γ. Francisella-induced PGE2 can also elicit production of a >10 kDa soluble host factor termed FTMØSN (F. tularensis macrophage supernatant), which acts on IFN-γ pre-activated MØ to down-regulate MHC class II expression via a ubiquitin-dependent mechanism, blocking antigen presentation to CD4 T cells. Here, we report that FTMØSN-induced down-regulation of MØ class II is the result of the induction of MARCH1, and that MØ expressing MARCH1 “resistant” class II molecules are resistant to FTMØSN-induced class II down-regulation. Since PGE2 can induce IL-10 production and IL-10 is the only reported cytokine able to induce MARCH1 expression in monocytes and dendritic cells, these findings suggested that IL-10 is the active factor in FTMØSN. However, use of IL-10 knockout MØ established that IL-10 is not the active factor in FTMØSN, but rather that Francisella-elicited PGE2 drives production of a >10 kDa host factor distinct from IL-10. This factor then drives MØ IL-10 production to induce MARCH1 expression and the resultant class II down-regulation. Since many human pathogens such as Salmonella typhi, Mycobacterium tuberculosis and Legionella pneumophila also induce production of host PGE2, these results suggest that a yet-to-be-identified PGE2-inducible host factor capable of inducing IL-10 is central to the immune evasion mechanisms of multiple important human pathogens

    Extended self-knowledge

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    We aim to move the externalism and self-knowledge debate forward by exploring two novel sceptical challenges to the prospects of self-knowledge of a paradigmatic sort, both of which result from ways in which our thought content, cognitive processes and cognitive successes depend crucially on our external environments. In particular, it is shown how arguments from extended cognition (e.g., Clark A, Chalmers D. Analysis 58:7–19 (1998); Clark A. Supersizing the mind: Embodiment, action, and cognitive extension. Oxford: Oxford University Press (2008)) and situationism (e.g., Alfano M. The Philosophical Quarterly 62:223–249 (2012), Alfano M. Expanding the situationist challenge to reliabilism about inference. In Fairweather A (ed) Virtue epistemology naturalized, Springer, Dordrecht, pp 103–122 (2014); Doris JM. Noûs 32:504–530 (1998), Doris JM. Lack of character: Personality and moral behavior. Cambridge University Press, Cambridge (2002); Harman G. Proceedings of the Aristotelian Society. 99:315–331 (1999), Harman G. Proceedings of the Aristotelian Society 100:223–226 (2000)) pose hitherto unexplored challenges to the prospects of self-knowledge as it is traditionally conceived. It is shown, however, that, suitably understood, these apparent challenges in fact only demonstrate two ways in which our cognitive lives can be dependent on our environment. As such, rather than undermining our prospects for attaining self-knowledge, they instead illustrate how self-knowledge can be extended and expanded

    From icon of empire to national emblem: new evidence for the fallow deer of Barbuda

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    Barbuda and Antigua's national animal is the fallow deer, Dama dama dama, a species native to the eastern Mediterranean that has been transported around the world by people during the last 8,000 years. The timing and circumstances by which fallow deer came to be established on Barbuda are currently uncertain but, by examining documentary, osteological and genetic evidence, this paper will consider the validity of existing theories. It will review the dynamics of human-Dama relationships from the 1500s AD to the present day and consider how the meaning attached to this species has changed through time: from a symbol of colonial authority and dominance, to a 'walking larder' after the slave emancipation of 1834, and now an important part of the island's economy and cultural heritage that requires careful management
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