763 research outputs found

    Metformin prevents the effects of Pseudomonas aeruginosa on airway epithelial tight junctions and restricts hyperglycaemia-induced bacterial growth.

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    Lung disease and elevation of blood glucose are associated with increased glucose concentration in the airway surface liquid (ASL). Raised ASL glucose is associated with increased susceptibility to infection by respiratory pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. We have previously shown that the anti-diabetes drug, metformin, reduces glucose-induced S. aureus growth across in vitro airway epithelial cultures. The aim of this study was to investigate whether metformin has the potential to reduce glucose-induced P. aeruginosa infections across airway epithelial (Calu-3) cultures by limiting glucose permeability. We also explored the effect of P. aeruginosa and metformin on airway epithelial barrier function by investigating changes in tight junction protein abundance. Apical P. aeruginosa growth increased with basolateral glucose concentration, reduced transepithelial electrical resistance (TEER) and increased paracellular glucose flux. Metformin pre-treatment of the epithelium inhibited the glucose-induced growth of P. aeruginosa, increased TEER and decreased glucose flux. Similar effects on bacterial growth and TEER were observed with the AMP activated protein kinase agonist, 5-aminoimidazole-4-carboxamide ribonucleotide. Interestingly, metformin was able to prevent the P. aeruginosa-induced reduction in the abundance of tight junction proteins, claudin-1 and occludin. Our study highlights the potential of metformin to reduce hyperglycaemia-induced P. aeruginosa growth through airway epithelial tight junction modulation, and that claudin-1 and occludin could be important targets to regulate glucose permeability across airway epithelia and supress bacterial growth. Further investigation into the mechanisms regulating metformin and P. aeruginosa action on airway epithelial tight junctions could yield new therapeutic targets to prevent/suppress hyperglycaemia-induced respiratory infections, avoiding the use of antibiotics

    Blow-up profile of rotating 2D focusing Bose gases

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    We consider the Gross-Pitaevskii equation describing an attractive Bose gas trapped to a quasi 2D layer by means of a purely harmonic potential, and which rotates at a fixed speed of rotation Ω\Omega. First we study the behavior of the ground state when the coupling constant approaches a_a\_* , the critical strength of the cubic nonlinearity for the focusing nonlinear Schr{\"o}dinger equation. We prove that blow-up always happens at the center of the trap, with the blow-up profile given by the Gagliardo-Nirenberg solution. In particular, the blow-up scenario is independent of Ω\Omega, to leading order. This generalizes results obtained by Guo and Seiringer (Lett. Math. Phys., 2014, vol. 104, p. 141--156) in the non-rotating case. In a second part we consider the many-particle Hamiltonian for NN bosons, interacting with a potential rescaled in the mean-field manner a_NN2β1w(Nβx),with--a\_N N^{2\beta--1} w(N^{\beta} x), with wapositivefunctionsuchthat a positive function such that \int\_{\mathbb{R}^2} w(x) dx = 1.Assumingthat. Assuming that \beta < 1/2andthat and that a\_N \to a\_*sufficientlyslowly,weprovethatthemanybodysystemisfullycondensedontheGrossPitaevskiigroundstateinthelimit sufficiently slowly, we prove that the many-body system is fully condensed on the Gross-Pitaevskii ground state in the limit N \to \infty$

    Formation of Supermassive Black Holes

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    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.Comment: To appear in The Astronomy and Astrophysics Review. The final publication is available at http://www.springerlink.co

    The Cold Peace: Russo-Western Relations as a Mimetic Cold War

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    In 1989–1991 the geo-ideological contestation between two blocs was swept away, together with the ideology of civil war and its concomitant Cold War played out on the larger stage. Paradoxically, while the domestic sources of Cold War confrontation have been transcended, its external manifestations remain in the form of a ‘legacy’ geopolitical contest between the dominant hegemonic power (the United States) and a number of potential rising great powers, of which Russia is one. The post-revolutionary era is thus one of a ‘cold peace’. A cold peace is a mimetic cold war. In other words, while a cold war accepts the logic of conflict in the international system and between certain protagonists in particular, a cold peace reproduces the behavioural patterns of a cold war but suppresses acceptance of the logic of behaviour. A cold peace is accompanied by a singular stress on notions of victimhood for some and undigested and bitter victory for others. The perceived victim status of one set of actors provides the seedbed for renewed conflict, while the ‘victory’ of the others cannot be consolidated in some sort of relatively unchallenged post-conflict order. The ‘universalism’ of the victors is now challenged by Russia's neo-revisionist policy, including not so much the defence of Westphalian notions of sovereignty but the espousal of an international system with room for multiple systems (the Schmittean pluriverse)

    Chronic non-specific low back pain - sub-groups or a single mechanism?

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    Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches. Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention. Summary: The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed

    Parallels, prescience and the past: analogical reasoning and contemporary international politics

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    Analogical reasoning has held a perpetual appeal to policymakers who have often drafted in historical metaphor as a mode of informing decision-making. However, this article contends that since the beginning of the ‘War on Terror’ we have arguably seen the rise of a more potent form of analogy, namely ones that are selected because they fulfil an ideological function. Analogical reasoning as a tool of rational decision-making has increasingly become replaced by analogical reasoning as a tool of trenchant ideologically-informed policy justification. This article addresses three key areas which map out the importance of analogical reasoning to an understanding of developments in contemporary international politics: the relationship between history and politics, in intellectual and policy terms; a critical assessment of the appeal that analogical reasoning holds for policymakers; and the development of a rationale for a more effective use of history in international public policymaking

    Deep Theorizing in International Relations

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    This paper starts from the observation that, at a time when the popularity of grand theory is in decline among IR scholars, they do not agree on what they mean by theory. In fact, the celebration of theoretical pluralism is accompanied by the relative absence of a serious conversation about what ‘theory’ is, could, or should be. Taking the view that we need such a conversation, this puts forward the notion of ‘deep theorizing’. Countering both the shallow theorizing of modern scholarship that conflates theory with scientific method, and the postmodern view that abstract narratives must be deconstructed and rejected, it offers a reading of the parameters along which substantial theorizing proceeds. Specifically, it suggests that ‘deep theorizing’ is the conceptual effort of explaining (inter)action by developing a reading of drives/basic motivations and the ontology of its carrier through an account of the human condition, that is, a particular account of how the subject (the political actor) is positioned in social space and time. The paper illustrates the plausibility of this meta-theoretical angle in a discussion of realist, liberal and postcolonial schools of thought

    The misuses of sustainability: adult education, citizenship and the dead hand of neoliberalism

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    ‘‘Sustainability’’ has a captivating but disingenuous simplicity: its meanings are complex, and have political and policy significance. Exploring the application of the term to adult education, this paper argues that a particular discourse of ‘‘sustainability’’ has become a common-sense, short-circuiting critical analysis and understanding of policy options. This ‘‘business discourse’’ of sustainability, strongly influenced by neoliberal ideas, encourages the presumption that educational programmes and movements which have died out were unsustainable, bound to fail, and even responsible – having failed to adapt – for their own demise. Potentially valuable experience is thus excluded from the educational policy canon. The author uses three cases from 20th-century adult education, namely (1) English liberal adult education; (2) ‘‘mass education’’, also known as community development, in the British colonies; and (3) UNESCO’s Fundamental Education, to challenge this presumption. He demonstrates for each case how a business discourse has implied their ‘‘unsustainability’’, but that the reality was more complex and involved external political intervention

    The mimetic politics of lone-wolf terrorism

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    Written at a time of crisis in the project of social and political modernity, Fyodor Dostoevsky’s 1864 novel Notes from Underground offers an intriguing parallel for the twenty-first century lone-wolf; it portrays an abject, outcast, spiteful unnamed anti-hero boiling with rage, bitter with resentment and on the verge of radicalisation. A Girardian reading of the poetic truths contained in Dostoevsky’s work is able to provide important keys to explain the contemporary transformation from ‘fourth-wave’ religious terrorism to ‘fifth-wave’ lone-wolf terrorism. Such a reading argues that it is mimetic rivalry – rather than much-trumpeted forms of religious violence or cultural differences – that fuels the triangular relation between governments, terrorists and civilian victims at heart of terrorist acts. This approach is further able to blend social inquiry with an account of the individual, in fact anthropological, conditions of lone-wolf terrorism by tracing the globalisation of resentment and the individualisation of violence to the hyper-mimeticism characterising the globalisation of late modernity. Finally, a mimetic reading of ‘fifth-wave’ terrorism accounts for the turbulence of a global politics in which victimhood and scapegoating no longer have the ability to stabilise social order and warns against a future where violence proliferates and escalates unchecked

    Bringing analysis of gender and social–ecological resilience together in small-scale fisheries research: Challenges and opportunities

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    The demand for gender analysis is now increasingly orthodox in natural resource programming, including that for small-scale fisheries. Whilst the analysis of social–ecological resilience has made valuable contributions to integrating social dimensions into research and policy-making on natural resource management, it has so far demonstrated limited success in effectively integrating considerations of gender equity. This paper reviews the challenges in, and opportunities for, bringing a gender analysis together with social–ecological resilience analysis in the context of small-scale fisheries research in developing countries. We conclude that rather than searching for a single unifying framework for gender and resilience analysis, it will be more effective to pursue a plural solution in which closer engagement is fostered between analysis of gender and social-ecological resilience whilst preserving the strengths of each approach. This approach can make an important contribution to developing a better evidence base for small-scale fisheries management and policy
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