2,056 research outputs found

    Potential Role of Ultrafine Particles in Associations between Airborne Particle Mass and Cardiovascular Health

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    Numerous epidemiologic time-series studies have shown generally consistent associations of cardiovascular hospital admissions and mortality with outdoor air pollution, particularly mass concentrations of particulate matter (PM) ≀2.5 or ≀10 ÎŒm in diameter (PM(2.5), PM(10)). Panel studies with repeated measures have supported the time-series results showing associations between PM and risk of cardiac ischemia and arrhythmias, increased blood pressure, decreased heart rate variability, and increased circulating markers of inflammation and thrombosis. The causal components driving the PM associations remain to be identified. Epidemiologic data using pollutant gases and particle characteristics such as particle number concentration and elemental carbon have provided indirect evidence that products of fossil fuel combustion are important. Ultrafine particles < 0.1 ÎŒm (UFPs) dominate particle number concentrations and surface area and are therefore capable of carrying large concentrations of adsorbed or condensed toxic air pollutants. It is likely that redox-active components in UFPs from fossil fuel combustion reach cardiovascular target sites. High UFP exposures may lead to systemic inflammation through oxidative stress responses to reactive oxygen species and thereby promote the progression of atherosclerosis and precipitate acute cardiovascular responses ranging from increased blood pressure to myocardial infarction. The next steps in epidemiologic research are to identify more clearly the putative PM casual components and size fractions linked to their sources. To advance this, we discuss in a companion article (Sioutas C, Delfino RJ, Singh M. 2005. Environ Health Perspect 113:947–955) the need for and methods of UFP exposure assessment

    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

    Visual Similarity Perception of Directed Acyclic Graphs: A Study on Influencing Factors

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    While visual comparison of directed acyclic graphs (DAGs) is commonly encountered in various disciplines (e.g., finance, biology), knowledge about humans' perception of graph similarity is currently quite limited. By graph similarity perception we mean how humans perceive commonalities and differences in graphs and herewith come to a similarity judgment. As a step toward filling this gap the study reported in this paper strives to identify factors which influence the similarity perception of DAGs. In particular, we conducted a card-sorting study employing a qualitative and quantitative analysis approach to identify 1) groups of DAGs that are perceived as similar by the participants and 2) the reasons behind their choice of groups. Our results suggest that similarity is mainly influenced by the number of levels, the number of nodes on a level, and the overall shape of the graph.Comment: Graph Drawing 2017 - arXiv Version; Keywords: Graphs, Perception, Similarity, Comparison, Visualizatio

    Clarifying Assumptions about Intraoperative Stress during Surgical Performance: More Than a Stab in the Dark: Reply

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    Ó The Author(s) 2011. This article is published with open access at Springerlink.com We thank Dr. Ali for his concise annotation of our efforts to validate a tool that evaluates mental workload in surgery [1, 2]. Unlike other safety critical domains, the field of surgery has been slow to acknowledge the impact of intraoperative stress on surgical performance, but recently a sea change has been triggered by authorities in the field of surgical education [3]. We agree with Ali that stress is not by default detrimental to performance. Our aim was to develop a diagnostic tool that identifies the factors that contribute to disrupted performance, should it occur. Indeed, studies of the effects of acute stress on operating performance have shown considerable variability, ranging from no effect to either facilitative or debilitative effects [3–5]. The Yerkes-Dodson law emerged from the earliest attempts to explain the relationship between physiological arousal and performance, but it has been criticized for treating stress as a unitary construct, influenced solely by physiological factors [6]. More recently, Catastrophe Theory has been invoked to model the relationship, using both physiological and psychological (cognitive anxiety) components of stress [7]. The model proposes that physiological arousal displays a mild inverted-U relationship with performance when cognitive anxiety is low, but that catastrophic declines in performance can occur if both physiological arousal and cognitive anxiety are high. Recent surgical literature has elucidated the complexity of M. Wilson (&amp;

    A systematic review investigating fatigue, psychological and cognitive impairment following TIA and minor stroke:protocol paper

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    Approximately 20,000 people have a transient ischemic attack (TIA) and 23,375 have a minor stroke in England each year. Fatigue, psychological and cognitive impairments are well documented post-stroke. Evidence suggests that TIA and minor stroke patients also experience these impairments; however, they are not routinely offered relevant treatment. This systematic review aims to: (1) establish the prevalence of fatigue, anxiety, depression, post-traumatic stress disorder (PTSD) and cognitive impairment following TIA and minor stroke and to investigate the temporal course of these impairments; (2) explore impact on quality of life (QoL), change in emotions and return to work; (3) identify where further research is required and to potentially inform an intervention study

    Inheritance of isozyme and RFLP markers in Brassica campestris and comparison with B. oleracea

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    Using primarily cDNA restriction fragment length polymorphism markers (RFLPs) previously located to Brassica oleracea (cabbage, 2n=18) chromosomes, we initiated a comparative RFLP map in an F 2 population of B. campestris (turnip x mock pak-choi, 2n=20). As with B. oleracea , the genome of B. campestris showed extensive gene duplication, and the majority of detected duplicated loci were unlinked. Only 6 of the 49 identified loci were represented as a single copy, and 3 of these 6 were clustered on a single linkage group showing a distorted segregation ratio. Comparison with B. Oleracea indicates this synteny is conserved between species. Two other linkage groups also appeared syntenic between B. oleracea and B. campestris . One single copy locus appears to have changed synteny between B. oleracea and B. campestris . These observations suggest that B. oleracea and B. campestris share a common ancestor, but that chromosome repatterning has occurred during or after speciation. Within B. campestris , 5 loci appeared duplicated in one parent or the other, and 2 of these were linked. Differentiation through subspecies-specific duplication or deletion events is suggested as one mechansim for the evolution of numerous morphotypes within each of these species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46007/1/122_2004_Article_BF00227309.pd

    Characterisation of sugar beet (Beta vulgaris L. ssp. vulgaris) varieties using microsatellite markers

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    <p>Abstract</p> <p>Background</p> <p>Sugar beet is an obligate outcrossing species. Varieties consist of mixtures of plants from various parental combinations. As the number of informative morphological characteristics is limited, this leads to some problems in variety registration research.</p> <p>Results</p> <p>We have developed 25 new microsatellite markers for sugar beet. A selection of 12 markers with high quality patterns was used to characterise 40 diploid and triploid varieties. For each variety 30 individual plants were genotyped. The markers amplified 3-21 different alleles. Varieties had up to 7 different alleles at one marker locus. All varieties could be distinguished. For the diploid varieties, the expected heterozygosity ranged from 0.458 to 0.744. The average inbreeding coefficient F<sub>is </sub>was 0.282 ± 0.124, but it varied widely among marker loci, from F<sub>is </sub>= +0.876 (heterozygote deficiency) to F<sub>is </sub>= -0.350 (excess of heterozygotes). The genetic differentiation among diploid varieties was relatively constant among markers (F<sub>st </sub>= 0.232 ± 0.027). Among triploid varieties the genetic differentiation was much lower (F<sub>st </sub>= 0.100 ± 0.010). The overall genetic differentiation between diploid and triploid varieties was F<sub>st </sub>= 0.133 across all loci. Part of this differentiation may coincide with the differentiation among breeders' gene pools, which was F<sub>st </sub>= 0.063.</p> <p>Conclusions</p> <p>Based on a combination of scores for individual plants all varieties can be distinguished using the 12 markers developed here. The markers may also be used for mapping and in molecular breeding. In addition, they may be employed in studying gene flow from crop to wild populations.</p

    A novel PKC activating molecule promotes neuroblast differentiation and delivery of newborn neurons in brain injuries

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    Neural stem cells are activated within neurogenic niches in response to brain injuries. This results in the production of neuroblasts, which unsuccessfully attempt to migrate toward the damaged tissue. Injuries constitute a gliogenic/non-neurogenic niche generated by the presence of anti-neurogenic signals, which impair neuronal differentiation and migration. Kinases of the protein kinase C (PKC) family mediate the release of growth factors that participate in different steps of the neurogenic process, particularly, novel PKC isozymes facilitate the release of the neurogenic growth factor neuregulin. We have demonstrated herein that a plant derived diterpene, (EOF2; CAS number 2230806-06-9), with the capacity to activate PKC facilitates the release of neuregulin 1, and promotes neuroblasts differentiation and survival in cultures of subventricular zone (SVZ) isolated cells in a novel PKC dependent manner. Local infusion of this compound in mechanical cortical injuries induces neuroblast enrichment within the perilesional area, and noninvasive intranasal administration of EOF2 promotes migration of neuroblasts from the SVZ towards the injury, allowing their survival and differentiation into mature neurons, being some of them cholinergic and GABAergic. Our results elucidate the mechanism of EOF2 promoting neurogenesis in injuries and highlight the role of novel PKC isozymes as targets in brain injury regeneration

    The morphologies of massive galaxies at 1 < z < 3 in the CANDELS-UDS field : compact bulges, and the rise and fall of massive discs

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    We have used high-resolution, Hubble Space Telescope, near-infrared imaging to conduct a detailed analysis of the morphological properties of the most massive galaxies at high redshift, modelling the WFC3/IR H-160-band images of the similar or equal to 200 galaxies in the CANDELS-UDS field with photometric redshifts 1 10(11)M(circle dot). We have explored the results of fitting single-Sersic and bulge+disc models, and have investigated the additional errors and potential biases introduced by uncertainties in the background and the on-image point spread function. This approach has enabled us to obtain formally acceptable model fits to the WFC3/IR images of > 90 per cent of the galaxies. Our results indicate that these massive galaxies at 1 2 the compact bulges display effective radii a factor of similar or equal to 4 smaller than local ellipticals of comparable mass. These trends also appear to extend to the bulge components of disc-dominated galaxies. In addition, we find that, while such massive galaxies at low redshift are generally bulge-dominated, at redshifts 1 2 they are mostly disc-dominated. The majority of the disc-dominated galaxies are actively forming stars, although this is also true for many of the bulge-dominated systems. Interestingly, however, while most of the quiescent galaxies are bulge-dominated, we find that a significant fraction (25-40 per cent) of the most quiescent galaxies, with specific star formation rates sSFR < 10(-10) yr(-1), have disc-dominated morphologies. Thus, while our results show that the massive galaxy population is undergoing dramatic changes at this crucial epoch, they also suggest that the physical mechanisms which quench star formation activity are not simply connected to those responsible for the morphological transformation of massive galaxies into present-day giant ellipticals
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