224 research outputs found

    X-Type Interface for Management of Multidomain Multitechnology Networks

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    The specification and implementation of Xcoop interfaces has received great attention in the last few years. In fact, the appropriate design of this system component is a key aspect for efficient and seamless co-operative management. In this context it is worth mentioning the EURESCOM P408 project and the standards of the European Telecommunication Standards Institute (ETSI) in Europe and the ITU-T and Telemanagement Forum related work worldwide. The Xcoop specification presented in this paper, produced as part of the results of the project MISA co-funded by the Commission of the European Union, is a step ahead in the evolution of this system interface. Distinguished from preceding works, this one allows interactions between management systems independently to the underlying network technology, ATM, SDH or hybrid. This is achieved by defining appropriate functionality and an information model, indeed, where the specific characteristics of ATM and SDH resources are abstracted and merged in common classes.Peer ReviewedPostprint (published version

    Performance evaluation of a linear predictor frequency estimator for mobile flat fading wireless channels

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    A well known frequency estimation algorithm using the linear prediction method is analyzed for flat fading wireless channels. The estimator outputs are statistically analyzed and its jitter performances are compared with the non-fading case and the Cramer-Rao bound. We provide a closed form solution for the distribution and the variance of the frequency estimates under fading conditions by making valid assumptions. We also verify the theoretical model using simulations. Analysis shows that the variance of the estimates for flat fading channels reaches a threshold point and increasing the transmit power does not necessarily improve the performances any further

    Cryptococcal meningitis presenting with bilateral complete ophthalmoplegia: a case report

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    BACKGROUND: Cryptococcus neoformans is saprophytic encapsulated yeast. Infection is acquired by inhalation of the organism and could be asymptomatic or limited to the lungs, specially in the immunocompetent host. Cryptococcal meningitis is a serious opportunistic infection among post transplant recipients. Cranial nerve palsies and ophthalmoplegia are well known complications of this disease, but bilateral complete ophthalmoplegia is a very rare presentation. CASE PRESENTATION: A Sri Lankan young male, who is a post kidney transplant recipient, presented with bilateral complete ophthalmoplegia and subsequently was diagnosed to have cryptococcal meningitis based on Indian ink stain and culture of cerebrospinal fluid (CSF). His magnetic resonance imaging (MRI) showed bilateral multiple nodular lesions in both basal ganglia and thalami. Brainstem imaging was normal. CONCLUSIONS: Cryptococcal meningitis is a serious fungal infection in post transplant patients. It should be suspected in any immunocompromised patient with fever, headache and focal neurological signs. Bilateral thalamic lesions, inflammation and invasion of the cranial nerves and raised intracranial pressure were thought to be possible mechanisms resulting in bilateral complete ophthalmoplegia in this patient

    Stabilization and Anticancer Enhancing Activity of the Peptide Nisin by Cyclodextrin-Based Nanosponges against Colon and Breast Cancer Cells

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    The great variability of cancer types demands novel drugs with broad spectrum, this is the case of Nisin, a polycyclic antibacterial peptide that recently has been considered for prevention of cancer cells growth. As an accepted food additive, this drug would be very useful for intestinal cancers, but the peptide nature would make easier its degradation by digestion procedures. For that reason, the aim of present study to investigate the protective effect of two different ÎČ-cyclodextrin-based nanosponges (carbonyl diimidazole and pyromellitic dianhydride) and their anti-cancer enhancement effect of Nisin-Z encapsulated with against colon cancer cells (HT-29). To extend its possible use, a comparison with breast (MCF-7) cancer cell was carried out. The physicochemical properties, loading efficiency, and release kinetics of Nisin complex with nanosponges were studied. Then, tricin-SDS-PAGE electrophoresis was used to understand the effect of NSs on stability of Nisin-Z in the presence of gastric peptidase pepsin. In addition, the cytotoxicity and cell membrane damage of Nisin Z were evaluated by using the MTT and LDH assay, which was complemented via Annexin-V/ Propidium Iodide (PI) by using flowcytometry. CD-NS are able to complex Nisin-Z with an encapsulation efficiency around 90%. A protective effect of Nisin-Z complexed with CD-NSs was observed in presence of pepsin. An increase in the percentage of apoptotic cells was observed when the cancer cells were exposed to Nisin Z complexed with nanosponges. Interestingly, Nisin Z free and loaded on PMDA/CDI-NSs is more selectively toxic towards HT-29 cells than MCF-7 cancer cells. These results indicated that nanosponges might be good candidates to protect peptides and deliver drugs against intestinal cancers

    Dark Coupling and Gauge Invariance

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    We study a coupled dark energy-dark matter model in which the energy-momentum exchange is proportional to the Hubble expansion rate. The inclusion of its perturbation is required by gauge invariance. We derive the linear perturbation equations for the gauge invariant energy density contrast and velocity of the coupled fluids, and we determine the initial conditions. The latter turn out to be adiabatic for dark energy, when assuming adiabatic initial conditions for all the standard fluids. We perform a full Monte Carlo Markov Chain likelihood analysis of the model, using WMAP 7-year data.Comment: 16 pages, 2 figures, version accepted for publication in JCA

    Comparative evaluation of solubility, cytotoxicity and photostability studies of resveratrol and oxyresveratrol loaded nanosponges

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    Resveratrol and oxyresveratrol are natural polyphenolic stilbenes with several important pharmacological activities. However, low solubility and aqueous instability are the major limitations in their drug delivery applications. In the present work, we demonstrated the encapsulation of resveratrol and oxyresveratrol with nanosponge to improve solubility and stability. Several characterization techniques were used to confirm the encapsulation of both drug molecules within the nanosponges. The high encapsulation efficiency of resveratrol (77.73%) and oxyresveratrol (80.33%) was achieved within the nanosponges. Transmission electron microscopy suggested uniform spherical size particles of resveratrol and oxyresveratrol loaded nanosponges. Compared to free drugs, better protection against UV degradation was observed for resveratrol-loaded nanosponge (2-fold) and oxyresveratrol-loaded nanosponge (3-fold). Moreover, a higher solubilization of resveratrol- and oxyresveratrol-loaded nanosponges lead to a better antioxidant activity compared to drug molecules alone. Cytotoxicity studies against DU-145 prostate cancer cell lines further suggested improved activity of both resveratrol and oxyresveratrol-loaded nanosponges without any significant toxicity of blank nanosponges

    Dark Sector from Interacting Canonical and Non-Canonical Scalar Fields

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    In this work it is investigated general models with interactions between two canonical scalar fields and between one non-canonical (tachyon-type) and one canonical scalar field. The potentials and couplings to the gravity are selected through the Noether symmetry approach. These general models are employed to describe interactions between dark energy and dark matter, with the fields being constrained by the astronomical data. The cosmological solutions of some cases are compared with the observed evolution of the late Universe.Comment: 20 pages, 13 figures, correction of misprints in eqs. (4), (5), (43), (44

    The new resilience of emerging and developing countries: systemic interlocking, currency swaps and geoeconomics

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    The vulnerability/resilience nexus that defined the interaction between advanced and developing economies in the post-WWII era is undergoing a fundamental transformation. Yet, most of the debate in the current literature is focusing on the structural constraints faced by the Emerging and Developing Countries (EDCs) and the lack of changes in the formal structures of global economic governance. This paper challenges this literature and its conclusions by focusing on the new conditions of systemic interlocking between advanced and emerging economies, and by analysing how large EDCs have built and are strengthening their economic resilience. We find that a significant redistribution of ‘policy space’ between advanced and emerging economies have taken place in the global economy. We also find that a number of seemingly technical currency swap agreements among EDCs have set in motion changes in the very structure of global trade and finance. These developments do not signify the end of EDCs’ vulnerability towards advanced economies. They signify however that the economic and geoeconomic implications of this vulnerability have changed in ways that constrain the options available to advanced economies and pose new challenges for the post-WWII economic order
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