194 research outputs found

    On the spectral efficiency for selection combiner diversity (SCD) over slow fading

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    In this paper we derive closed-form expressions for the single-user capacity of selection combining diversity (SCD) system, taking into account the effect of imperfect channel estimation at the receiver. The channel considered is a slowly varying spatially independent flat Rayleigh fading channel. The complex channel estimate and the actual channel are modelled as jointly Gaussian random variables with a correlation that depends on the estimation quality. Two adaptive transmission schemes are analyzed: 1) optimal power and rate adaptation; and 2) constant power with optimal rate adaptation. Our numerical results show the effect of Gaussian channel estimation error on the achievable spectral efficiency

    Ten kilodalton heat shock protein (HSP10) is overexpressed during carcinogenesis of large bowel and uterine exocervix

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    In the present study, we evaluated the presence and the level of expression of HSP10 in two carcinogenetic models: the 'adenoma-carcinoma sequence' of large bowel and the 'dysplasia-carcinoma sequence' of uterine exocervix. We found HSP10 was overexpressed during the carcinogenesis of both organs. In particular, HSP10 was overexpressed early in large bowel carcinogenesis, while the expression of this protein in exocervical carcinogenesis gradually increased from normal through dysplastic to neoplastic tissues. The quantitative analysis of immunohistochemistry and the Western blotting confirmed these results. Our previous observations showed overexpression of HSP60 in the same carcinogenetic models. This report correlates the overexpression of HSP10 with that of HSP60 during carcinogenesis in vivo. These results could stimulate further studies on the pathogenetic role of these proteins during the carcinogenesis as well as their use as diagnostic and prognostic tools in oncology. \ua9 2003 Elsevier Science Ltd. All rights reserved

    PRENATAL DEVELOPMENT OF TEMPORO-MANDIBULAR JOINTS: STATE OF ART

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    The aim of this work is to analyze the state of the art of temporo-mandibular joint (MJ) to understand the varoius stage of the development of the same during embryogenesis. Various theories have been analyzed, such as the formation of apoptotic or the important role of growth factors, or the Valencia et studies in which are analyzed to numerous articular diseases in various stage of development. By the aforementioned studies show that many factors, of a different nature, are to be involved in the prenatal developlment of this important joint

    Nonbinary LDPC-Coded Sphere-Packed Transmit Diversity

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    Do neurologists agree in diagnosing drug resistance in adults with focal epilepsy?

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    OBJECTIVE: To evaluate interrater agreement in categorizing treatment outcomes and drug responsiveness status according to the International League Against Epilepsy (ILAE) definition of drug-resistant epilepsy. METHODS: A total of 1053 adults with focal epilepsy considered by the investigators to meet ILAE criteria for drug resistance were enrolled consecutively at 43 centers and followed up prospectively for 18-34 months. Treatment outcomes for all antiepileptic drugs (AEDs) used up to enrollment (retrospective assessment), and on an AED newly introduced at enrollment, were categorized by individual investigators and by 2 rotating members of a 16-member expert panel (EP) that reviewed the patient records independently. Interrater agreement was tested by Cohen's kappa (k) statistics and rated according to Landis and Koch's criteria. RESULTS: Agreement between EP members in categorizing outcomes on the newly introduced AED was almost perfect (90.1%, k = 0.84, 95% confidence interval [CI] 0.80-0.87), whereas agreement between the EP and individual investigators was moderate (70.4%, k = 0.57, 95% CI 0.53-0.61). Similarly, categorization of outcomes on previously used AEDs was almost perfect between EP members (91.7%, k = 0.83, 95% CI 0.81-0.84) and moderate between the EP and investigators (68.2%, k = 0.50, 95% CI 0.48-0.52). Disagreement was related predominantly to outcomes considered to be treatment failures by the investigators but categorized as undetermined by the EP. Overall, 19% of patients classified as having drug-resistant epilepsy by the investigators were considered by the EP to have "undefined responsiveness." SIGNIFICANCE: Interrater agreement in categorizing treatment outcomes according to ILAE criteria ranges from moderate to almost perfect. Nearly 1 in 5 patients considered by enrolling neurologists to be "drug-resistant" were classified by the EP as having "undefined responsiveness.

    Differential effects of saturated and unsaturated fatty acids on autophagy in pancreatic β-cells

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    Long-chain saturated fatty acids are lipotoxic to pancreatic β-cells, whereas most unsaturates are better tolerated and some may even be cytoprotective. Fatty acids alter autophagy in β-cells and there is increasing evidence that such alterations can impact directly on the regulation of viability. Accordingly, we have compared the effects of palmitate (C16:0) and palmitoleate (C16:1) on autophagy in cultured β-cells and human islets. Treatment of BRIN-BD11 β-cells with palmitate led to enhanced autophagic activity, as judged by cleavage of microtubule-associated protein 1 light chain 3-I (LC3-I) and this correlated with a marked loss of cell viability in the cells. In addition, transfection of these cells with an mCherry-YFP-LC3 reporter construct revealed the accumulation of autophagosomes in palmitate-treated cells, indicating an impairment of autophagosome-lysosome fusion. This was also seen upon addition of the vacuolar ATPase inhibitor, bafilomycin A1. Exposure of BRIN-BD11 cells to palmitoleate (C16:1) did not lead directly to changes in autophagic activity or flux, but it antagonised the actions of palmitate. In parallel, palmitoleate also improved the viability of palmitate-treated BRIN-BD11 cells. Equivalent responses were observed in INS-1E cells and in isolated human islets. Taken together, these data suggest that palmitate may cause an impairment of autophagosome-lysosome fusion. These effects were not reproduced by palmitoleate which, instead, antagonised the responses mediated by palmitate suggesting that attenuation of β-cell stress may contribute to the improvement in cell viability caused by the mono-unsaturated fatty acid.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.The authors are grateful to Diabetes UK for financial support via project grants 14/0005093 and 15/0005156 (to N G M) and a PhD studentship (14/0005093) to Patricia Thomas. They also thank Dr Jon Lane (University of Bristol) for the kind gift of a dual-fluorescence LC3 reporter construct.accepted version (12 month embargo), submitted versio

    Fabrication of periodic microstructures on flexible polyimide membranes

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    Periodic metallic microstructures were fabricated on polyimide membranes. Techniques were developed to maintain flatness of the membrane during processing while still allowing for flexibility in the final structure. For proper functionality of the structures, it was necessary to first fabricate a continuous metallic film and a continuous dielectric layer on top of the flexible substrate, which underlaid the periodic microstructure. Flexibility of the overall structure was maintained by using a polymer as the dielectric layer, which was constrained to have high optical transmission over the infrared wavelength range of 6-14 mu m. Three candidate polymers were evaluated, and their measured optical properties are presented. Benzocyclobutene was found to be the best choice for this application. The final structure fully populated a 10 cm (4 in.) diameter flexible membrane with microstructures of excellent uniformity. (C) 2007 American Vacuum Society

    Medium-term culture of normal human oral mucosa: a novel three-dimensional model to study the effectiveness of drugs administration.

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    Tissue-engineered oral mucosal equivalents have been developed for in vitro studies for a few years now. However, the usefulness of currently available models is still limited by many factors, mainly the lack of a physiological extracellular matrix (ECM) and the use of cell populations that do not reflect the properly differentiated cytotypes of the mucosa of the oral cavity. For this reason, we have developed a novel three-dimensional culture model reflecting the normal architecture of the human oral mucosa, with the main aim of creating a better in vitro model where to test cellular responses to drugs administration. This novel 3D cell culture model (3D outgrowth) was set up using an artificial extracellular matrix (MatrigelTM), allowing the interactions required for proper differentiation of the various citotypes which form the mucosal layer. Biopsies of human oral mucosa, in fragments of about 0.5 mm3, were placed onto 6.5mm Transwells, covered with MatrigelTM and grown in a specific culture medium. A gradual formation of an architectural structure similar to that of the in vivo oral mucosa was observed. Transmission electron and confocal microscopy were employed to characterize the newly developed model: the cell components (keratinocytes and fibroblasts) differentiated properly within the outgrowth and reconstituted, in vitro, the physiological structure of the human oral mucosa, including a stratified non-keratinized squamous layer composed of four different layers, a proper basal membrane and a lamina propria where fibroblasts produce ECM. Moreover, keratinocytes expressed CK5, CK13, CK19 and E-cadherin, whereas fibroblasts expressed collagen type I and IV, laminin and fibronectin. 3D outgrowths could be considered a valid alternative to animal models, and provide useful information for researchers interested in studying the responses of the human oral mucosa to locally delivered drugs or other exogenous treatments
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