111 research outputs found

    Debt levels, debt composition, and sovereign spreads in emerging and advanced economies

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    This paper studies the relationship between sovereign spreads and the interaction between debt composition and debt levels in advanced and emerging market countries. It finds that in emerging market countries there is a significant correlation between spreads and debt levels. This correlation, however, is not statistically significant in countries where most public debt is denominated in local currency. In advanced economies, the magnitude of the correlation between debt levels and spreads is about one fifth of the corresponding correlation for emerging market economies. In Eurozone countries, however, the correlation between spreads and debt ratios is similar to that of emerging market countries. The paper also shows that the financial crisis amplified the relationship between spreads and debt levels within the Eurozone but had no effect on the relationship between spreads and debt in standalone countries. Finally, the paper shows that the relationship between debt levels and spreads is amplified by the presence of large net foreign liabilities. This amplifying effect of net foreign liabilities is larger in the Eurozone than in standalone advanced economies. The paper concludes that debt composition matters and corroborates the original sin hypothesis that, rather than being a mere reflection of institutional weaknesses, the presence of foreign currency debt increases financial fragility and leads to suboptimal macroeconomic policies

    External morphology of the immature stages of Neotropical heliconines: VI. Dione moneta moneta Hübner (Lepidoptera, Nymphalidae, Heliconiini)

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    The external features of the egg, larva and pupa of Dione moneta moneta Hübner, 1825 are described and illustrated, based upon light and scanning electron microscopy.As estruturas externas do ovo, larva e pupa de Dione moneta moneta Hübner, 1825 são descritas e ilustradas, baseadas em microscopia óptica e eletrônica de varredura.1323Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Effect of interchain separation on the photoinduced absorption spectra of polycarbazolyldiacetylenes

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    The photoinduced absorption spectra of a novel polycarbazolyldiacetylene with long aliphatic chains on the carbazolyl side groups are measured and compared with those of the unsubstituted polyDCHD. The two polymers in the blue form exhibit very similar electronic absorption spectra and Raman frequencies. This fact indicates that the conjugation length of the polydiacetylene backbone is not too affected by the long substituents. In contrast, the near steady-state photoinduced absorption spectra show that different photogeneration mechanisms are involved in the two polymers. This result can be ascribed to the role played by the interchain distance in the dynamics of the relaxation processes in polydiacetylenes

    Multi-Modality Therapeutics with Potent Anti-Tumor Effects: Photochemical Internalization Enhances Delivery of the Fusion Toxin scFvMEL/rGel

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    BACKGROUND: There is a need for drug delivery systems (DDS) that can enhance cytosolic delivery of anti-cancer drugs trapped in the endo-lysosomal compartments. Exposure of cells to specific photosensitizers followed by light exposure (photochemical internalization, PCI) results in transfer of agents from the endocytic compartment into the cytosol. METHODOLOGY AND PRINCIPAL FINDINGS: The recombinant single-chain fusion construct scFvMEL/rGel is composed of an antibody targeting the progenitor marker HMW-MAA/NG2/MGP/gp240 and the highly effective toxin gelonin (rGel). Here we demonstrate enhanced tumor cell selectivity, cytosolic delivery and anti-tumor activity by applying PCI of scFvMEL/rGel. PCI performed by light activation of cells co-incubated with scFvMEL/rGel and the endo-lysosomal targeting photosensitizers AlPcS(2a) or TPPS(2a) resulted in enhanced cytotoxic effects against antigen-positive cell lines, while no differences in cytotoxicity between the scFvMEL/rGel and rGel were observed in antigen-negative cells. Mice bearing well-developed melanoma (A-375) xenografts (50-100 mm(3)) were treated with PCI of scFvMEL/rGel. By 30 days after injection, approximately 100% of mice in the control groups had tumors>800 mm(3). In contrast, by day 40, 50% of mice in the PCI of scFvMEL/rGel combination group had tumors<800 mm(3) with no increase in tumor size up to 110 days. PCI of scFvMEL/rGel resulted in a synergistic effect (p<0.05) and complete regression (CR) in 33% of tumor-bearing mice (n = 12). CONCLUSIONS/SIGNIFICANCE: This is a unique demonstration that a non-invasive multi-modality approach combining a recombinant, targeted therapeutic such as scFvMEL/rGel and PCI act in concert to provide potent in vivo efficacy without sacrificing selectivity or enhancing toxicity. The present DDS warrants further evaluation of its clinical potential
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