251 research outputs found

    SYNCHRONIZATION OF PCM NETWORKS

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    Hospitality, Culture and Regeneration: Urban decay, entrepreneurship and the "ruin" bars of Budapest

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    This paper considers the relationships between hospitality, culture and urban regeneration through an examination of rom (ruin) venues, which operate in dilapidated buildings in Budapest, Hungary. The paper reviews previous work on culture and urban regeneration in order to locate the role of hospitality within emerging debates. It subsequently interrogates the evolution of the rom phenomenon and demonstrates how, in this context, hospitality thrives because of social and physical decay in urban locations, how operators and entrepreneurs exploit conflicts among various actors involved in regeneration, and how hospitality may be mobilised purposefully in the regeneration process. The paper demonstrates how networked entrepreneurship maintains these operations and how various forms of cultural production are entangled and mobilised in the venues’ hospitality propositions

    A Counterexample Regarding Labelled Well-Quasi-Ordering

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    Korpelainen, Lozin, and Razgon conjectured that a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by only finitely many minimal forbidden induced subgraphs is labelled well-quasi-ordered, a notion stronger than that of n-well-quasi-order introduced by Pouzet in the 1970s. We present a counterexample to this conjecture. In fact, we exhibit a hereditary property of graphs which is well-quasi-ordered by the induced subgraph order and defined by finitely many minimal forbidden induced subgraphs yet is not 2-well-quasi-ordered. This counterexample is based on the widdershins spiral, which has received some study in the area of permutation patterns

    Pre-Excitation Studies for Rubidium-Plasma Generation

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    The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.Comment: 8 pages, 6 figures, submitted to Nucl. Inst. and Meth. in Phys. Res.

    Mechanistic study of an immobilized molecular electrocatalyst by in situ gap-plasmon-assisted spectro-electrochemistry

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    Immobilised first-row transition metal complexes are potential low-cost electrocatalysts for selective CO2 conversion to produce renewable fuels. Mechanistic understanding of their function is vital for the development of next-generation catalysts, though poor surface sensitivity of many techniques makes this challenging. Here, a nickel bis(terpyridine) complex is introduced as a CO2 reduction electrocatalyst in a unique electrode geometry, sandwiched by thiol anchoring moieties between two gold surfaces. Gap-plasmon-assisted surface-enhanced Raman scattering spectroscopy coupled with density functional theory calculations reveals the nature of the anchoring group plays a pivotal role in the catalytic mechanism by eliminating ligand loss. Our in-situ spectro-electrochemical measurement enables the detection of as few as 8 molecules undergoing redox transformations in the individual gold-sandwiched nanocavities, together with the calibration of electrical fields via vibrational Stark effects. This advance allows rapid exploration of non-resonant redox reactions at the few-molecule level and provides scope for future mechanistic studies of single-molecules

    Steiner trees for hereditary graph classes.

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    We consider the classical problems (Edge) Steiner Tree and Vertex Steiner Tree after restricting the input to some class of graphs characterized by a small set of forbidden induced subgraphs. We show a dichotomy for the former problem restricted to (H1,H2) -free graphs and a dichotomy for the latter problem restricted to H-free graphs. We find that there exists an infinite family of graphs H such that Vertex Steiner Tree is polynomial-time solvable for H-free graphs, whereas there exist only two graphs H for which this holds for Edge Steiner Tree. We also find that Edge Steiner Tree is polynomial-time solvable for (H1,H2) -free graphs if and only if the treewidth of the class of (H1,H2) -free graphs is bounded (subject to P≠NP ). To obtain the latter result, we determine all pairs (H1,H2) for which the class of (H1,H2) -free graphs has bounded treewidth

    Innate Immunity in Human Embryonic Stem Cells: Comparison with Adult Human Endothelial Cells

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    Treatment of human disease with human embryonic stem cell (hESC)-derived cells is now close to reality, but little is known of their responses to physiological and pathological insult. The ability of cells to respond via activation of Toll like receptors (TLR) is critical in innate immune sensing in most tissues, but also extends to more general danger sensing, e.g. of oxidative stress, in cardiomyocytes. We used biomarker release and gene-array analysis to compare responses in hESC before and after differentiation, and to those in primary human endothelial cells. The presence of cardiomyocytes and endothelial cells was confirmed in differentiated cultures by immunostaining, FACS-sorting and, for cardiomyocytes, beating activity. Undifferentiated hESC did not respond with CXCL8 release to Gram positive or Gram negative bacteria, or a range of PAMPs (pathogen associated molecular patterns) for TLRs 1-9 (apart from flagellin, an activator of TLR5). Surprisingly, lack of TLR-dependent responses was maintained over 4 months of differentiation of hESC, in cultures which included cardiomyocytes and endothelial cells. In contrast, primary cultures of human aortic endothelial cells (HAEC) demonstrated responses to a broad range of PAMPs. Expression of downstream TLR signalling pathways was demonstrated in hESC, and IL-1β, TNFα and INFγ, which bypass the TLRs, stimulated CXCL8 release. NFκB pathway expression was also present in hESC and NFκB was able to translocate to the nucleus. Low expression levels of TLRs were detected in hESC, especially TLRs 1 and 4, explaining the lack of response of hESC to the main TLR signals. TLR5 levels were similar between differentiated hESC and HAEC, and siRNA knockdown of TLR5 abolished the response to flagellin. These findings have potential implications for survival and function of grafted hESC-derived cells

    Impact of CT-apelin and NT-proBNP on identifying non-responders to cardiac resynchronization therapy

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    CONTEXT: Assessment of response to cardiac resynchronization therapy (CRT) is essential. OBJECTIVE: To assess the predictive value of CT-apelin together with NT-proBNP in patients undergoing CRT. METHODS: Serum CT-apelin and NT-proBNP were measured by ELISA before, and 6-month after CRT. Primary endpoint was non-response (<4% increase in LVEF) after 6-month. RESULTS: From 81 patients, 15 proved to be non-responders. Six-month CT-apelin was superior compared to NT-proBNP in identifying non-responders by multivariate ROC (CT-apelin:p = 0.01, NT-proBNP:p = 0.13) and by logistic regression (CT-apelin:p = 0.01, NT-proBNP:p = 0.41) analyzes. CONCLUSION: Six-month CT-apelin might be valuable novel biomarker in identifying non-responders to CRT that was superior to NT-proBNP

    Host-Guest Chemistry Meets Electrocatalysis: Cucurbit[6]uril on a Au Surface as a Hybrid System in CO2 Reduction.

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    The rational control of forming and stabilizing reaction intermediates to guide specific reaction pathways remains to be a major challenge in electrocatalysis. In this work, we report a surface active-site engineering approach for modulating electrocatalytic CO2 reduction using the macrocycle cucurbit[6]uril (CB[6]). A pristine gold surface functionalized with CB[6] nanocavities was studied as a hybrid organic-inorganic model system that utilizes host-guest chemistry to influence the heterogeneous electrocatalytic reaction. The combination of surface-enhanced infrared absorption (SEIRA) spectroscopy and electrocatalytic experiments in conjunction with theoretical calculations supports capture and reduction of CO2 inside the hydrophobic cavity of CB[6] on the gold surface in aqueous KHCO3 at negative potentials. SEIRA spectroscopic experiments show that the decoration of gold with the supramolecular host CB[6] leads to an increased local CO2 concentration close to the metal interface. Electrocatalytic CO2 reduction on a CB[6]-coated gold electrode indicates differences in the specific interactions between CO2 reduction intermediates within and outside the CB[6] molecular cavity, illustrated by a decrease in current density from CO generation, but almost invariant H2 production compared to unfunctionalized gold. The presented methodology and mechanistic insight can guide future design of molecularly engineered catalytic environments through interfacial host-guest chemistry
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