16 resultados para Gerry Boyle

em Aston University Research Archive


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Transglutaminase 2 (TG2) is a protein crosslinking enzyme with several additional biochemical functions. Loss of TG2 in vivo results in impaired phagocytosis of apoptotic cells and altered proinflammatory cytokine production by macrophages engulfing apoptotic cells leading to autoimmunity. It has been proposed that TG2 acts as an integrin ß(3) coreceptor in the engulfment process, while altered proinflammatory cytokine production is related to the lack of latent TGFß activation by TG2 null macrophages. Here we report that TG2 null macrophages respond to lipopolysaccharide treatment by elevated IL-6 and TNFa production. Though TGFß has been proposed to act as a feed back regulator of proinflammatory cytokine production in LPS-stimulated macrophages, this phenomenon is not related to the lack of active TGFß production. Instead, in the absence of TG2 integrin ß(3) maintains an elevated basal Src family kinase activity in macrophages, which leads to enhanced phosphorylation and degradation of the I?Ba. Low basal levels of I?Ba explain the enhanced sensitivity of TG2 null macrophages to signals that regulate NF-?B. Our data suggest that TG2 null macrophages bear a proinflammatory phenotype, which might contribute to the enhanced susceptibility of these mice to develop autoimmunity and atherosclerosis.

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Specific association of tissue transglutaminase (tTG) with matrix fibronectin (FN) results in the formation of an extracellular complex (tTG-FN) with distinct adhesive and pro-survival characteristics. tTG-FN supports RGD-independent cell adhesion of different cell types and the formation of distinctive RhoA-dependent focal adhesions following inhibition of integrin function by competitive RGD peptides and function blocking anti-integrin antibodies alpha5beta1. Association of tTG with its binding site on the 70-kDa amino-terminal FN fragment does not support this cell adhesion process, which seems to involve the entire FN molecule. RGD-independent cell adhesion to tTG-FN does not require transamidating activity, is mediated by the binding of tTG to cell-surface heparan sulfate chains, is dependent on the function of protein kinase Calpha, and leads to activation of the cell survival focal adhesion kinase. The tTG-FN complex can maintain cell viability of tTG-null mouse dermal fibroblasts when apoptosis is induced by inhibition of RGD-dependent adhesion (anoikis), suggesting an extracellular survival role for tTG. We propose a novel RGD-independent cell adhesion mechanism that promotes cell survival when the anti-apoptotic role mediated by RGD-dependent integrin function is reduced as in tissue injury, which is consistent with the externalization and binding of tTG to fibronectin following cell damage/stress.

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The well-established sociolinguistic literature on complimenting claims that compliments are formulaic (Manes and Wolfson 1981). The purpose of this thesis is to demonstrate that the claim is invalid, to describe an alternative approach to the study of compliments, and to draw on an extensive collection of compliments in order to show that complimenting is a diverse, interactive process. A prerequisite for such work is a means of deciding whether a given utterance is a compliment, but this issue is neglected in the literature. The conversation analytic notion of preference appeared capable of providing this criterion, but research revealed that it was too ill-defined to serve such a purpose. The thesis was, therefore, obliged to clarify the notion of preference before applying it to a study of compliments. The necessary clarification was found in the enthnomethodological roots of conversation analysis, and the thesis provides a clear and consistent means of determining whether utterances are preferred to dispreferred. The criteria used in the determination of preference are applied, in the final chapter, to the study of compliments. The results of the study contrast markedly with those of the sociolinguistic researchers, and they provide significant grounds for rejecting the claim that compliments are formulaic.

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Using panel data for twenty-seven post-communist economies between 1987-2003, we examine the nexus of relationships between inequality, fiscal capacity (defined as the ability to raise taxes efficiently) and the political regime. Investigating the impact of political reform we find that full political freedom is associated with lower levels of income inequality. Under more oligarchic (authoritarian) regimes, the level of inequality is conditioned by the state’s fiscal capacity. Specifically, oligarchic regimes with more developed fiscal systems are able to defend the prevailing vested interests at a lower cost in terms of social injustice. This empirical finding is consistent with the model developed by Acemoglu (2006). We also find that transition countries undertaking early macroeconomic stabilisation now enjoy lower levels of inequality; we confirm that education fosters equality and the suggestion of Commander et al (1999) that larger countries are prone to higher levels of inequality.

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Book review: British local government into the 21st century. Gerry Stoker and David Wilson (eds) Palgrave Macmillan, 2004, 304 pp., £50.60 (hb), £18.99 (pb) ISBN: 1403918724

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A recent article in the Lancet, by David Stuckler, Larry King and Martin McKee, investigated anew the fluctuations in adult male mortality rates that have come to characterise the so-called post-communist mortality crisis. Adopting a cross-country, time-series perspective the authors examined how the economic policy strategies of the 1990s impacted upon observed fluctuations in mortality. They conclude that the adoption of a strategy of rapid (mass) privatisation contributed to the adverse mortality trends. We subject that finding to closer scrutiny using the same data from which the Stuckler et al claim stems. We find that their claim that mass privatisation adversely affected male mortality trends in the post-Communist world does not stand up to closer examination. It is not supported empirically and is at odds with what we know about both transition in the post-communist world and about health trends over time in this region.

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Using data for the period 1989 – 2002, we examine the determinants of income inequality in post-communist economies. We find a strong positive association between equality and tax collection but note that this relationship is significantly stronger under authoritarian regimes than under democracies. We also discover that countries introducing sustainable democratic institutions early are characterised by lower inequality. We also confirm that education fosters equality and find that larger countries are prone to higher levels of inequality.

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Using data on Polish firms this paper examines the relationship between corporate control structures, sales growth and the determinants of employment change. Privatised and de novo firms are the main drivers of employment growth; in the case of de novo firms, it is foreign ownership which underpins the result. Being privatised has a positive impact on employment but this is concentrated within a range of 3–6 years after privatisation. There are no systematic differences in employment response to negative sales growth across the ownership categories. Employment in state firms is less responsive to positive sales growth. From these results we infer that the behaviour of state firms is affected by both insider rent sharing and binding budget constraints.

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Using panel data pertaining to large Polish (non-financial) firms this paper examines the determinants of employment change during the period 1996-2002. Paying particular attention to the asymmetry hypothesis we investigate the impact of own wages, outside wages, output growth, regional characteristics and sectoral affiliation on the evolution of employment. In keeping with the 'right to manage' model we find that employment dynamics are not affected negatively by alternative wages. Furthermore, in contrast to the early transition period, we find evidence that employment levels respond to positive sales growth (in all but state firms). The early literature, (e.g. Kollo, 1998) found that labour hoarding lowered employment elasticities in the presence of positive demand shocks. Our findings suggest that inherited labour hoarding may no longer be a factor. We argue that the present pattern of employment adjustment is better explained by the role of insiders. This tentative conclusion is hinged on the contrasting behaviour of state and privatised companies and the similar behaviour of privatised and new private companies. We conclude that lower responsiveness of employment to both positive and negative changes in revenue in state firms is consistent with the proposition that rent sharing by insiders is stronger in the state sector.

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Using panel data on large Polish firms this paper examines the relationship between corporate control structures, sales growth and the determinants of employment change during the period 1996-2002. We find that privatised and de novo firms are the main drivers of employment growth and that, in the case of de novo firms, it is foreign ownership which underpins the result. Interestingly, we find that being privatised has a positive impact on employment growth but that this impact is concentrated within a range of three to six years after privatisation. In contrast with the findings of earlier literature, we find evidence that there are no systematic differences in employment response to negative sales growth across the ownership categories. On the other hand, employment in state firms is less responsive to positive sales growth. From these combined results we infer that the behaviour of state firms is constrained by both insider rent sharing and binding budget constraints. Consistent with this, we find that privatised companies, three to six years post-privatisation, are the firms for whom employment is most responsive to positive sales growth and as such, offer the best hope for rapid labour market expansion.

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Drawing on a dataset covering more than 100 countries from 1970 to 2007, we estimate the impact of different types of financial crises on male and female mortality. We find that only currency crises have a direct short-term impact on mortality rates. We stylize our reading of the key empirical evidence of this paper in the following way: of three distinct types of financial crises, it is currency crises that have a direct short-term impact on mortality rates, and this is particularly the case for males.

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Noxious stimuli in the esophagus cause pain that is referred to the anterior chest wall because of convergence of visceral and somatic afferents within the spinal cord. We sought to characterize the neurophysiological responses of these convergent spinal pain pathways in humans by studying 12 healthy subjects over three visits (V1, V2, and V3). Esophageal pain thresholds (Eso-PT) were assessed by electrical stimulation and anterior chest wall pain thresholds (ACW-PT) by use of a contact heat thermode. Esophageal evoked potentials (EEP) were recorded from the vertex following 200 electrical stimuli, and anterior chest wall evoked potentials (ACWEP) were recorded following 40 heat pulses. The fear of pain questionnaire (FPQ) was administered on V1. Statistical data are shown as point estimates of difference +/- 95% confidence interval. Pain thresholds increased between V1 and V3 [Eso-PT: V1-V3 = -17.9 mA (-27.9, -7.9) P < 0.001; ACW-PT: V1-V3 = -3.38 degrees C (-5.33, -1.42) P = 0.001]. The morphology of cortical responses from both sites was consistent and equivalent [P1, N1, P2, N2 complex, where P1 and P2 are is the first and second positive (downward) components of the CEP waveform, respectively, and N1 and N2 are the first and second negative (upward) components, respectively], indicating activation of similar cortical networks. For EEP, N1 and P2 latencies decreased between V1 and V3 [N1: V1-V3 = 13.7 (1.8, 25.4) P = 0.02; P2: V1-V3 = 32.5 (11.7, 53.2) P = 0.003], whereas amplitudes did not differ. For ACWEP, P2 latency increased between V1 and V3 [-35.9 (-60, -11.8) P = 0.005] and amplitudes decreased [P1-N1: V1-V3 = 5.4 (2.4, 8.4) P = 0.01; P2-N2: 6.8 (3.4, 10.3) P < 0.001]. The mean P1 latency of EEP over three visits was 126.6 ms and that of ACWEP was 101.6 ms, reflecting afferent transmission via Adelta fibers. There was a significant negative correlation between FPQ scores and Eso-PT on V1 (r = -0.57, P = 0.05). These data provide the first neurophysiological evidence of convergent esophageal and somatic pain pathways in humans.

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The deliberate addition of Gaussian noise to cochlear implant signals has previously been proposed to enhance the time coding of signals by the cochlear nerve. Potentially, the addition of an inaudible level of noise could also have secondary benefits: it could lower the threshold to the information-bearing signal, and by desynchronization of nerve discharges, it could increase the level at which the information-bearing signal becomes uncomfortable. Both these effects would lead to an increased dynamic range, which might be expected to enhance speech comprehension and make the choice of cochlear implant compression parameters less critical (as with a wider dynamic range, small changes in the parameters would have less effect on loudness). The hypothesized secondary effects were investigated with eight users of the Clarion cochlear implant; the stimulation was analogue and monopolar. For presentations in noise, noise at 95% of the threshold level was applied simultaneously and independently to all the electrodes. The noise was found in two-alternative forced-choice (2AFC) experiments to decrease the threshold to sinusoidal stimuli (100 Hz, 1 kHz, 5 kHz) by about 2.0 dB and increase the dynamic range by 0.7 dB. Furthermore, in 2AFC loudness balance experiments, noise was found to decrease the loudness of moderate to intense stimuli. This suggests that loudness is partially coded by the degree of phase-locking of cochlear nerve fibers. The overall gain in dynamic range was modest, and more complex noise strategies, for example, using inhibition between the noise sources, may be required to get a clinically useful benefit. © 2006 Association for Research in Otolaryngology.