398 research outputs found

    High-Speed Communications Over Polymer Optical Fibers for In-Building Cabling and Home Networking

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    This paper focuses on high-speed cabling using polymer optical fibers (POF) in home networking. In particular, we report about the results obtained in the POF-ALL European Project, which is relevant to the Sixth Framework Program, and after two years of the European Project POF-PLUS, which is relevant to the Seventh Framework Program, focusing on their research activities about the use of poly-metyl-metha-acrilate step-index optical fibers for home applications. In particular, for that which concerns POF-ALL, we will describe eight-level pulse amplitude modulation (8-PAM) and orthogonal frequency-division multiplexing (OFDM) approaches for 100-Mb/s transmission over a target distance of 300 m, while for that which concerns POF-PLUS, we will describe a fully digital and a mixed analog-digital solution, both based on intensity modulation direct detection, for transmitting 1 Gb/s over a target distance of 50 m. The ultimate experimental results from the POF-ALL project will be given, while for POF-PLUS, which is still ongoing, we will only show our most recent preliminary results

    Real-Time 100Gb/s Downstream PAM4 PON Link with 34 dB Power Budget

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    We experimentally demonstrate in real-time a 34dB PON power budget, exceeding E1 ODN class, with 100Gb/s PAM4 modulation using an amplified O-Band EML plus receiver-side optical amplification and only low complexity FFE equalization

    Enhanced Electrical Duobinary Decoder with Low-{BW} Based Receivers for Short Reach Indoor Optical Links

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    We propose and experimentally validate a novel scheme combining both binary and electrical duobinary detection. At 50Gb/s, in a 1-bit memory channel, we obtain a Rx sensitivity of -25.7dBm with a 25G-class Rx and a low path penalty after 20km using a 1342nm EML Tx

    Design of qos-aware energy-efficient fiber–wireless access networks

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    Energy-efficient network design has recently become a very important topic because of the energy cost increases in service providers’ infrastructures. This is of particular importance in access networks because of the growing demand for digital traffic by end users. Here we address the challenge of reducing the energy consumption of fiber–wireless (FiWi) access networks, that use both optical and radio frequency technologies to provide high bandwidth and ubiquity for end-user applications, while keeping delay under a threshold. Our goal is to find optimal sleep mode schedulings that allow energy consumption to be reduced while keeping packet delay acceptable. For this purpose a mathematical formalization and an algorithm are developed. The results show that the proposed approach is able to reduce the average packet delay, with negligible energy cost increases, in many scenarios, besides being computationally efficient and scalable. The proposed approach may, therefore, serve as a basis for planning and design of quality of service-aware energy-efficient FiWi access networks.This work was supported by FCT (Foundation for Science and Technology) of Portugal within CEOT (Center for Electronic, Optoelectronic and Telecommunications)

    On the pooling and subgrouping of data from percutaneous coronary intervention versus coronary artery bypass grafting trials: a call to circumspection

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    In the modern era, treatment choice is guided by scientific evidence, usually gathered from well-conducted clinical trials, and often followed by the pooling of their data. In this article, we review the most recent pooled evidence regarding myocardial revascularization strategies and discuss how these meta-analyses have inherent shortcomings that should be better understood, prior to their purported conclusions potentially influencing clinical decisions. Properly conducted randomized trials comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) can provide unbiased estimates of treatment effects. However, the design of such trials has often involved a primary outcome that is a composite measure and thus open to challenges with regard to the appropriate interpretation of each individual components. Quantitative synthesis of such data from multiple trials can enable estimates of individual components of the composite outcomes (e.g. all-cause mortality). Where individual patient data are available, a full investigation of mediating effects, or subgroups analyses, may also be undertaken. Relevant to this article, we now have multiple meta-analyses of trials available, which provide an opportunity to assess the appropriateness of criteria for patient selection between PCI and CABG. Consequently, we will appraise the robustness of these meta-analytic methods in answering the question at stake: does PCI provide equivalent results to CABG for the treatment of unprotected left main coronary artery stenosis and multivessel coronary artery disease

    Characteristics of cardiothoracic surgeons practicing at the top-ranked US institutions

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    BACKGROUND: We aimed to determine which factors distinguish cardiothoracic (CT) surgeons practicing at the top-ranked US institutions from their peers. METHODS: Using online resources, we collected demographics, training information and academic metrics of 694 cardiac (n=489; 70%) and thoracic (n=205; 30%) surgeons practicing at 57 preeminent US institutions, including those with the highest US News & World Report ranking ("top CT centers"). RESULTS: Two hundred and ninety-nine (43.1%) CT surgeons were practicing at the 18 "top CT centers" and had higher academic productivity (publications, citations) than their peers. While there was no difference in the proportion of international medical graduates (IMGs) (21.4% overall) or of surgeons with a PhD degree (9.4% overall) across institutions, the "top CT centers" had a higher proportion of faculty who received their entire CT training abroad (10.4% vs. 5.8%; P=0.038) or at highly-ranked US institutions. Those who published more during their early career years (residency, fellowship and first 5 years as faculty) were more likely to attain academic (professorship) and institutional leadership (division/department chair) positions and to practice at the "top CT centers". Women represented a minority (7.3% overall; 5.1% of cardiac vs. 12.7% of thoracic surgeons, P<0.001), but with growing prevalence among younger faculty and without differences across institutions. CONCLUSIONS: CT surgeons of the best US centers have a more international background and received their training at highly-ranked institutions. Early academic productivity is associated with life-long career achievements, with special importance of the first 5 years as faculty. Women represent a growing proportion of the CT surgical workforce

    Plastic Optical Fiber Technology for Reliable Home Networking: Overview and Results of the EU Project POF-ALL

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    The rising performance of broadband connections for residential users, particularly in conjunction with fiber to the home, will present a new challenge for telecom operators in the short and medium terms: how to deliver the high bit rate digital signals with high quality-of-service to all consumer devices scattered inside the building of final users? Among the many different solutions for the home network, we review in this article the use of polymer optical fibers for short-reach and high-capacity optical communications for residential customer premises. POF is an easy-to-install, low-cost, and eye-safe solution for these networks, with the potential of being future-proof. In this article the state of the art in POF technology is presented by summarizing significant results achieved in the European project POF-ALL. Data transmission rates of more than 1 Gb/s over 50+ m and 100 Mb/s over 200+ m of standard step-index POF have been show

    Nampt over-expression recapitulates the braf inhibitor resistant phenotype plasticity in melanoma

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    Serine&ndash;threonine protein kinase B-RAF (BRAF)-mutated metastatic melanoma (MM) is a highly aggressive type of skin cancer. Treatment of MM patients using BRAF/MEK inhibitors (BRAFi/MEKi) eventually leads to drug resistance, limiting any clinical benefit. Herein, we demonstrated that the nicotinamide adenine dinucleotide (NAD)-biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT) is a driving factor in BRAFi resistance development. Using stable and inducible NAMPT over-expression systems, we showed that forced NAMPT expression in MM BRAF-mutated cell lines led to increased energy production, MAPK activation, colony-formation capacity, and enhance tumorigenicity in vivo. Moreover, NAMPT over-expressing cells switched toward an invasive/mesenchymal phenotype, up-regulating expression of ZEB1 and TWIST, two transcription factors driving the epithelial to mesenchymal transition (EMT) process. Consistently, within the NAMPT-overexpressing cell line variants, we observed an increased percentage of a rare, drug-effluxing stem cell-like side population (SP) of cells, paralleled by up-regulation of ABCC1/MRP1 expression and CD133-positive cells. The direct correlation between NAMPT expression and gene set enrichments involving metastasis, invasiveness and mesenchymal/stemness properties were verified also in melanoma patients by analyzing The Cancer Genome Atlas (TCGA) datasets. On the other hand, CRISPR/Cas9 full knock-out NAMPT BRAFi-resistant MM cells are not viable, while inducible partial silencing drastically reduces tumor growth and aggressiveness. Overall, this work revealed that NAMPT over-expression is both necessary and sufficient to recapitulate the BRAFi-resistant phenotype plasticity
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