87 research outputs found

    Differential activation of killer cells in the circulation and the lung: a study of current smoking status and chronic obstructive pulmonary disease (COPD)

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    Background:CD8+ T-lymphocytes, natural killer T-like cells (NKT-like cells, CD56+CD3+) and natural killer cells (NK cells, CD56+CD3−) are the three main classes of human killer cells and they are implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Activation of these cells can initiate immune responses by virtue of their production of inflammatory cytokines and chemokines that cause lung tissue damage, mucus hypersecretion and emphysema. The objective of the current study was to investigate the activation levels of human killer cells in healthy non-smokers, healthy smokers, ex-smokers with COPD and current smokers with COPD, in both peripheral blood and induced sputum. Methods/Principal Findings:After informed consent, 124 participants were recruited into the study and peripheral blood or induced sputum was taken. The activation states and receptor expression of killer cells were measured by flow cytometry. In peripheral blood, current smokers, regardless of disease state, have the highest proportion of activated CD8+ T-lymphocytes, NKT-like cells and NK cells compared with ex-smokers with COPD and healthy non-smokers. Furthermore, CD8+ T-lymphocyte and NK cell activation is positively correlated with the number of cigarettes currently smoked. Conversely, in induced sputum, the proportion of activated killer cells was related to disease state rather than current smoking status, with current and ex-smokers with COPD having significantly higher rates of activation than healthy smokers and healthy non-smokers. Conclusions: A differential effect in systemic and lung activation of killer cells in COPD is evident. Systemic activation appears to be related to current smoking whereas lung activation is related to the presence or absence of COPD, irrespective of current smoking status. These findings suggest that modulating killer cell activation may be a new target for the treatment of COPD

    Monodisperse macromolecules – A stepping stone to understanding industrial polymers

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    AbstractPolymers synthesized via anionic polymerization have proved important to our fundamental understanding of the processing, that is rheology and crystallisation, of bulk commodity polymers. The role of monodisperse hydrogenated polybutadienes as models for linear and branched polyethylene is examined. Systematic studies of the effects of long-chain branching, using well-defined “comb” materials have improved our understanding of how the number and length of branches affect the rheological properties and how these features impact on their crystallization behaviour. A combination of techniques including rheology, Small Angle X-ray Scattering (SAXS), and birefringence measurements have provided insight into role of linear long chains in the formation of oriented morphologies during the crystallization of hydrogenated polybutadiene blends of controlled polydispersity leading to the development of a quantitative model

    Chip formation mechanism during orthogonal cutting of rubber microparticles and silica nanoparticles modified epoxy of polymers

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    The addition of well-dispersed nanoparticles can significantly increase the mechanical properties and toughness of epoxy polymers. In this study, an epoxy resin was modified by addition of silica nanoparticles, (CTBN) rubber microparticles and a combination of both. An in-situ orthogonal cutting rig combined with high magnification and high-speed imaging system was used to determine the effects on the chip formation mechanism and machining induced damage to the material. This study indicates that chip formation in silica-modified epoxy is governed by a fracture process with large cracks both at the machined surface level and subsurface within the chip formation zone. The presence of rubber enables larger plastic deformation within the epoxy-modified polymer as the toughening mechanism of the rubber deflects the generated cracks within the primary deformation zone. The magnitude of machining induced damage was found to be lower for rubber microparticles and was correlated with a rubber toughening mechanism observed during cutting. The higher magnitude of machining induced damage of silica-modified epoxy was linked to the material’s poor resistance to crack initiation and growth. These findings of the effect of rubber microparticles and silica nanoparticles on chip formation process will give engineers a greater ability to create a trade-off between filler properties vs material properties vs machining induced damage during Design for Manufacturing (DFM) stages of a product design

    Self-assembly-driven electrospinning:the transition from fibers to intact beaded morphologies

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    Polymer beads have attracted considerable interest for use in catalysis, drug delivery, and photo­nics due to their particular shape and surface morphology. Electrospinning, typically used for producing nanofibers, can also be used to fabricate polymer beads if the solution has a sufficiently low concentration. In this work, a novel approach for producing more uniform, intact beads is presented by electrospinning self-assembled block copolymer (BCP) solutions. This approach allows a relatively high polymer concentration to be used, yet with a low degree of entanglement between polymer chains due to microphase separation of the BCP in a selective solvent system. Herein, to demonstrate the technology, a well-studied polystyrene-poly(ethylene butylene)–polystyrene triblock copolymer is dissolved in a co-solvent system. The effect of solvent composition on the characteristics of the fibers and beads is intensively studied, and the mechanism of this fiber-to-bead is found to be dependent on microphase separation of the BCP

    Effects of tool coating and tool wear on the surface quality and flexural strength of slotted CFRP

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    Machining of carbon fibre reinforced polymer (CFRP) is abrasive and causes significant tool wear. The effect of tool wear on static flexural strength is investigated, using edge trimming with uncoated carbide and chemical vapour deposition (CVD) diamond coated burr style tools. Edge rounding (ER) criteria along with flank wear are used to observe tool degradation with ER shown to preferentially wear allowing the tool to become cyclically sharper and duller, corresponding to fluctuating dynamometer readings, a novelty for CFRP machining. Areal surface metrics degraded for an uncoated tool due to changes in cutting mechanism, whilst for up to 16.2 m of linear traverse, the coated tool showed limited changes. Tool wear, caused by edge trimming 7.2 m of CFRP, using an uncoated carbide tool, provided a flexural strength reduction of up to 10.5 %, directly linking tool wear to reduced mechanical strength

    Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study

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    Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14 years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (p < 0.001) in the fit group (mean 1.21 ± 3.42) compared to the unfit group (mean -0.74 ± 2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth

    Just a wind-up? Ethnicity, religion and prejudice in Scottish football-related comedy

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    This article probes how media representations of football in Scotland sustain the hegemonic ideologies associated with ethnicity and religion. The paper probes the football-related comedy output of one radio programme; radio output and football comedy are both neglected cultural material in studies of sport in Scotland. It argues that ambiguity and allusive language in comedy construct multiple interpretative possibilities that can demean the social and cultural identity of particular groups in society. The discussion analyses specific sketches from the Scottish radio comedy show Watson's Wind Up. It is concluded that although humorous, these sketches reveal how ideas, myths and stereotypes that coalesce round Celtic FC and the Irish-descended and Catholic communities in Scotland reinforce and sustain anti-Irish and anti-Catholic bigotry

    Liquid – liquid phase separation morphologies in ultra-white beetle scales and a synthetic equivalent

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    Cyphochilus beetle scales are amongst the brightest structural whites in nature, being highly opacifying whilst extremely thin. However, the formation mechanism for the voided intra- scale structure is unknown. Here we report 3D x-ray nanotomography data for the voided chitin networks of intact white scales of Cyphochilus and Lepidiota stigma. Chitin-filling frac- tions are found to be 31 ± 2% for Cyphochilus and 34 ± 1% for Lepidiota stigma, indicating previous measurements overestimated their density. Optical simulations using finite- difference time domain for the chitin morphologies and simulated Cahn-Hilliard spinodal structures show excellent agreement. Reflectance curves spanning filling fraction of 5-95% for simulated spinodal structures, pinpoint optimal whiteness for 25% chitin filling. We make a simulacrum from a polymer undergoing a strong solvent quench, resulting in highly reflective ( 94%) white films. In-situ X-ray scattering confirms the nanostructure is formed through spinodal decomposition phase separation. We conclude that the ultra-white beetle scale nanostructure is made via liquid–liquid phase separation

    Does 1,8-diiodooctane affect the aggregation state of PC71BM in solution?

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    1,8-Diiodooctane (DIO) is an additive used in the processing of organic photovoltaics and has previously been reported, on the basis of small-angle X-ray scattering (SAXS) measurements, to deflocculate nano-aggregates of [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) in chlorobenzene. We have critically re-examined this finding in a series of scattering measurements using both X-rays and neutrons. With SAXS, we find that the form of the background solvent scattering is influenced by the presence of DIO, that there is substantial attenuation of the X-rays by the background solvent and that there appears to be beam-induced aggregation. All three factors call into question the suitability of SAXS for measurements on these samples. By contrast, small-angle neutron scattering (SANS) measurements, performed at concentrations of 15 mg ml−1 up to and including 40 mg ml−1, show no difference in the aggregation state for PC71BM in chlorobenzene with and without 3% DIO; we find PC71BM to be molecularly dissolved in all solvent cases. In situ film thinning measurements of spin-coated PC71BM solution with the DIO additive dry much slower. Optical imaging shows that the fullerene films possess enhanced molecular mobility in the presence of DIO and it is this which, we conclude, improves the nanomorphology and consequently solar cell performance. We propose that any compatible high boiling solvent would be expected to show the same behaviour
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