303 research outputs found

    Priming Picture Naming with a Semantic Task: An fMRI Investigation

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    Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms

    The neural correlates of picture naming facilitated by auditory repetition

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    Background: Overt repetition of auditorily presented words can facilitate picture naming performance in both unimpaired speakers and individuals with word retrieval difficulties, but the underlying neurocognitive mechanisms and longevity of such effects remain unclear. This study used functional magnetic resonance imaging to examine whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from an auditory repetition task in healthy older adults

    A shifting enemy: analysing the BBC’s representations of “al-Qaeda” in the aftermath of the September 11th 2001 attacks

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    This article seeks to explore how the BBC made sense of the al-Qaeda phenomenon in its flagship “News at Ten” bulletin during the aftermath of the September 11th 2001 attacks. Using Critical Multimodal Discourse Analysis, it shows how the BBC’s representations function as a dynamic and continually shifting site upon which a range of fears, identities, discourses and forms of knowledge and power struggle and contend, and through which a number of different “al-Qaedas” manifest themselves. In particular, three shifting modes of visual and verbal representation are identified within the BBC’s coverage which each correspond to a separate understanding of al-Qaeda: the “Islamic” mode, the “Personalised” mode and the “Elusive” mode. These representations both draw upon and challenge the dominant discourses surrounding Islam, non-state terrorism and the identities of terrorist suspects, providing audiences with a variety of often conflicting ways of seeing and speaking about this entity. As such, the article provides insight into the complex nature of the BBC’s representations of al-Qaeda during its coverage of the September 11th 2001 attacks, and shows how such complexity serves, albeit inadvertently, to legitimise the far-reaching counterterrorism policies that were enacted in the aftermath of these attacks

    Influence of the Escherichia coli oxyR gene function on λ prophage maintenance

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    In Escherichia coli hosts, hydrogen peroxide is one of the factors that may cause induction of λ prophage. Here, we demonstrate that H2O2-mediated λ prophage induction is significantly enhanced in the oxyR mutant host. The mRNA levels for cI gene expression were increased in a λ lysogen in the presence of H2O2. On the other hand, stimulation of the pM promoter by cI857 overproduced from a multicopy plasmid was decreased in the ΔoxyR mutant in the presence of H2O2 but not under normal growth conditions. The purified OxyR protein did bind specifically to the pM promoter region. This binding impaired efficiency of interaction of the cI protein with the OR3 site, while stimulating such a binding to OR2 and OR1 sites, in the regulatory region of the pM promoter. We propose that changes in cI gene expression, perhaps in combination with moderately induced SOS response, may be responsible for enhanced λ prophage induction by hydrogen peroxide in the oxyR mutant. Therefore, OxyR seems to be a factor stimulating λ prophage maintenance under conditions of oxidative stress. This proposal is discussed in the light of efficiency of induction of lambdoid prophages bearing genes coding for Shiga toxins

    A genome-wide association study of corneal astigmatism: The CREAM Consortium

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    PURPOSE: To identify genes and genetic markers associated with corneal astigmatism. METHODS: A meta-analysis of genome-wide association studies (GWASs) of corneal astigmatism undertaken for 14 European ancestry (n=22,250) and 8 Asian ancestry (n=9,120) cohorts was performed by the Consortium for Refractive Error and Myopia. Cases were defined as having >0.75 diopters of corneal astigmatism. Subsequent gene-based and gene-set analyses of the meta-analyzed results of European ancestry cohorts were performed using VEGAS2 and MAGMA software. Additionally, estimates of single nucleotide polymorphism (SNP)-based heritability for corneal and refractive astigmatism and the spherical equivalent were calculated for Europeans using LD score regression. RESULTS: The meta-analysis of all cohorts identified a genome-wide significant locus near the platelet-derived growth factor receptor alpha (PDGFRA) gene: top SNP: rs7673984, odds ratio=1.12 (95% CI:1.08–1.16), p=5.55×10−9. No other genome-wide significant loci were identified in the combined analysis or European/Asian ancestry-specific analyses. Gene-based analysis identified three novel candidate genes for corneal astigmatism in Europeans—claudin-7 (CLDN7), acid phosphatase 2, lysosomal (ACP2), and TNF alpha-induced protein 8 like 3 (TNFAIP8L3). CONCLUSIONS: In addition to replicating a previously identified genome-wide significant locus for corneal astigmatism near the PDGFRA gene, gene-based analysis identified three novel candidate genes, CLDN7, ACP2, and TNFAIP8L3, that warrant further investigation to understand their role in the pathogenesis of corneal astigmatism. The much lower number of genetic variants and genes demonstrating an association with corneal astigmatism compared to published spherical equivalent GWAS analyses suggest a greater influence of rare genetic variants, non-additive genetic effects, or environmental factors in the development of astigmatism

    A genome-wide association study for corneal astigmatism: The CREAM Consortium

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    Purpose: To identify genes and genetic markers associated with corneal astigmatism. Methods: A meta-analysis was performed of genome-wide association studies (GWAS) of corneal astigmatism undertaken for 14 European ancestry (N = 22,250) and 8 Asian ancestry (N = 9,120) cohorts by the CREAM Consortium. Cases were defined as having >0.75 D of corneal astigmatism. For the meta-analysed results of European ancestry cohorts, subsequent gene-based and gene-set analyses were performed using VEGAS2 and MAGMA software. Additionally, estimates of SNP-based heritability for corneal and refractive astigmatism and spherical equivalent were calculated for Europeans using LD score regression. Results: Meta-analysis of all cohorts identified a genome-wide significant locus near the gene PDGFRA (platelet derived growth factor receptor alpha): top SNP: rs7673984, odds ratio = 1.12 (95% CI: 1.08-1.16), P = 5.55 x 10-9. No other genome-wide significant loci were identified in the combined analysis or European/Asian ancestry-specific analyses. Gene-based analysis identified 3 novel candidate genes for corneal astigmatism in Europeans: CLDN7 (claudin-7), ACP2 (acid phosphatase 2, lysosomal) and TNFAIP8L3 (TNF alpha induced protein 8 like 3). Conclusions: In addition to replicating a previously identified genome-wide significant locus for corneal astigmatism near the PDGFRA gene, gene-based analysis identified 3 novel candidate genes CLDN7, ACP2 and TNFAIP8L3 that warrant further investigation to understand their role in the pathogenesis of corneal astigmatism. The much lower number of genetic variants and genes demonstrating association with corneal astigmatism compared to published spherical equivalent GWAS analyses suggest a greater influence of rare genetic variants, non-additive genetic effects, or environmental factors to the development of astigmatism

    Associative Vocabulary Learning: Development and Testing of Two Paradigms for the (Re-) Acquisition of Action- and Object-Related Words

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    Despite a growing number of studies, the neurophysiology of adult vocabulary acquisition is still poorly understood. One reason is that paradigms that can easily be combined with neuroscientfic methods are rare. Here, we tested the efficiency of two paradigms for vocabulary (re-) acquisition, and compared the learning of novel words for actions and objects. Cortical networks involved in adult native-language word processing are widespread, with differences postulated between words for objects and actions. Words and what they stand for are supposed to be grounded in perceptual and sensorimotor brain circuits depending on their meaning. If there are specific brain representations for different word categories, we hypothesized behavioural differences in the learning of action-related and object-related words. Paradigm A, with the learning of novel words for body-related actions spread out over a number of days, revealed fast learning of these new action words, and stable retention up to 4 weeks after training. The single-session Paradigm B employed objects and actions. Performance during acquisition did not differ between action-related and object-related words (time*word category: p = 0.01), but the translation rate was clearly better for object-related (79%) than for action-related words (53%, p = 0.002). Both paradigms yielded robust associative learning of novel action-related words, as previously demonstrated for object-related words. Translation success differed for action- and object-related words, which may indicate different neural mechanisms. The paradigms tested here are well suited to investigate such differences with neuroscientific means. Given the stable retention and minimal requirements for conscious effort, these learning paradigms are promising for vocabulary re-learning in brain-lesioned people. In combination with neuroimaging, neuro-stimulation or pharmacological intervention, they may well advance the understanding of language learning to optimize therapeutic strategies

    DNA origami-based single-molecule forcespectroscopy elucidates RNA Polymerase IIIpre-initiation complex stability

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    The TATA-binding protein (TBP) and a transcription factor (TF) IIB-like factor are important constituents of all eukaryotic initiation complexes. The reason for the emergence and strict requirement of the additional initiation factor Bdp1 in the RNA polymerase (RNAP) III system, however, remained elusive. A poorly studied aspect in this context is the effect of DNA strain arising from DNA compaction and transcriptional activity on initiation complex formation. We made use of a DNA origami-based force clamp to follow the assembly of human initiation complexes in the RNAP II and RNAP III systems at the single-molecule level under piconewton forces. We demonstrate that TBP-DNA complexes are force-sensitive and TFIIB is sufficient to stabilise TBP on a strained promoter. In contrast, Bdp1 is the pivotal component that ensures stable anchoring of initiation factors, and thus the polymerase itself, in the RNAP III system. Thereby, we offer an explanation for the crucial role of Bdp1 for the high transcriptional output of RNAP III

    IMI - Myopia Genetics Report

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    The knowledge on the genetic background of refractive error and myopia has expanded dramatically in the past few years. This white paper aims to provide a concise summary of current genetic findings and defines the direction where development is needed. We performed an extensive literature search and conducted informal discussions with key stakeholders. Specific topics reviewed included common refractive error, any and high myopia, and myopia related to syndromes. To date, almost 200 genetic loci have been identified for refractive error and myopia, and risk variants mostly carry low risk but are highly prevalent in the general population. Several genes for secondary syndromic myopia overlap with those for common myopia. Polygenic risk scores show overrepresentation of high myopia in the higher deciles of risk. Annotated genes have a wide variety of functions, and all retinal layers appear to be sites of expression. The current genetic findings offer a world of new molecules involved in myopiagenesis. As the missing heritability is still large, further genetic advances are needed. This Committee recommends expanding large-scale, in-depth genetic studies using complementary big data analytics, consideration of gene-environment effects by thorough measurement of environmental exposures, and focus on subgroups with extreme phenotypes and high familial occurrence. Functional characterization of associated variants is simultaneously needed to bridge the knowledge gap between sequence variance and consequence for eye growth
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