323 research outputs found

    The Serum Level of Fibroblast Growth Factor-23 and Calcium-Phosphate Homeostasis in Obese Perimenopausal Women

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    Plasma FGF-23 concentrations and its relationship with calcium-phosphate homeostasis were evaluated in 48 perimenopausal obese women and in 29 nonobese controls. Serum parathyroid hormone, 25-hydroxyvitamin D3, CTX1, osteocalcin, total calcium, phosphorus, creatinine, and plasma intact FGF-23 concentrations were assessed. DXA of lumbar spine and femoral neck was performed to determine bone mineral density (BMD). Plasma iFGF-23 concentration was significantly higher in obese patients (by 42%) and correlated with age and BMD of proximal femur (R = −0.346; R = 0.285, resp.) but not with markers of bone turnover. However, serum phosphorus level in obese subjects was significantly lower. iFGF-23 concentration correlated significantly with body mass index (R = 0.292) and fat content (R = 0.259) in all study subjects. Moreover, a significant correlation between iFGF-23 and iPTH (R = 0.254) was found. No correlation between serum phosphorus or eGFR and plasma iFGF-23 and between eGFR and serum phosphorus was found. Elevated serum iFGF-23 concentration may partially explain lower phosphorus levels in the obese and seems not to reflect bone turnover

    The Berlin Exoplanet Search Telescope II. Catalog of Variable Stars. I. Characterization of Three Southern Target Fields

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    A photometric survey of three Southern target fields with BEST II yielded the detection of 2,406 previously unknown variable stars and an additional 617 stars with suspected variability. This study presents a catalog including their coordinates, magnitudes, light curves, ephemerides, amplitudes, and type of variability. In addition, the variability of 17 known objects is confirmed, thus validating the results. The catalog contains a number of known and new variables that are of interest for further astrophysical investigations, in order to, e.g., search for additional bodies in eclipsing binary systems, or to test stellar interior models. Altogether, 209,070 stars were monitored with BEST II during a total of 128 nights in 2009/2010. The overall variability fraction of 1.2-1.5% in these target fields is well comparable to similar ground-based photometric surveys. Within the main magnitude range of R[11,17]R\in\left[11,17\right], we identify 0.67(3)% of all stars to be eclipsing binaries, which indicates a completeness of about one third for this particular type in comparison to space surveys.Comment: accepted to A

    Variability survey in the CoRoT SRa01 field: Implications of eclipsing binary distribution on cluster formation in NGC 2264

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    Time-series photometry of the CoRoT field SRa01 was carried out with the Berlin Exoplanet Search Telescope II (BEST II) in 2008/2009. A total of 1,161 variable stars were detected, of which 241 were previously known and 920 are newly found. Several new, variable young stellar objects have been discovered. The study of the spatial distribution of eclipsing binaries revealed the higher relative frequency of Algols toward the center of the young open cluster NGC 2264. In general Algol frequency obeys an isotropic distribution of their angular momentum vectors, except inside the cluster, where a specific orientation of the inclinations is the case. We suggest that we see the orbital plane of the binaries almost edge-on.Comment: 18 pages, 8 figures, accepted for publication in Ap

    Switch-on Luminescent Sensing of Unlabelled Bacterial Lectin by Terbium(iii) Glycoconjugate Systems

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    Interactions of lectins with glycoconjugate-terbium(III) self-assembly complexes lead to sensing through enhanced lanthanide luminescence. This glycan-directed sensing paradigm detects an unlabelled lectin (LecA) associated with pathogen P. aeruginosa in solution, without any bactericidal activity. Further development of these probes could have potential as a diagnostic tool

    Transmit array as a viable 3D printing option for backhaul applications at V-band

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    Two designs of high gain dielectric lens for a Vband backhaul antenna, compatible with 3D printing, are compared. The available printing materials still have significant losses, which limit the performance of traditional focusing dielectric lenses, as the dome elliptical lens. Herein, we show that an all-dielectric transmit array can present several mechanical and electrical advantages, especially when high gains are required. We demonstrate that even with a compact transmit array (f/d = 067 it is still possible to comply with the usual bandwidth (57-66 GHz) and gain (>30 dBi) requirements for backhaul applications.info:eu-repo/semantics/acceptedVersio

    3D-Printed transmit-array antenna for broadband backhaul 5G links at V band

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    The low cost and compactness of transmit-array antennas (TAs) make them attractive for 5G backhaul links. However, the TA advantage is less obvious when considering the broadband operation requirement. Two main factors influence the bandwidth performance, namely: 1) the bandwidth of the unit cells, and 2) the number of 360° phase wrapping zones in the aperture, which are designed for a specific frequency. Herein, we overcome these limitations by using all-dielectric unit cells (inherently broadband) and by developing a general method to quantify and manage the intricate relation between antenna gain, bandwidth, and antenna height. Based on this framework we optimize, as an example, a TA design (focal distance, F=63 mm and aperture diameter D=80 mm ) to comply with typical gain specification for 5G backhaul links (>30 dBi) in the WiGiG band (from 57 to 66 GHz). The feed is a dedicated compact horn (8 ×5×22 mm3) that provides a proper illumination of the aperture. Additive manufacturing is used to simplify the manufacturing process of the antenna. A very good agreement between simulations and experimental results is obtained, achieving good aperture efficiency for this type of antenna (42%), which rivals with existing solutions based on more expensive manufacturing techniques.info:eu-repo/semantics/acceptedVersio

    Fitting a geometric graph to a protein-protein interaction network

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    Finding a good network null model for protein-protein interaction (PPI) networks is a fundamental issue. Such a model would provide insights into the interplay between network structure and biological function as well as into evolution. Also, network (graph) models are used to guide biological experiments and discover new biological features. It has been proposed that geometric random graphs are a good model for PPI networks. In a geometric random graph, nodes correspond to uniformly randomly distributed points in a metric space and edges (links) exist between pairs of nodes for which the corresponding points in the metric space are close enough according to some distance norm. Computational experiments have revealed close matches between key topological properties of PPI networks and geometric random graph models. In this work, we push the comparison further by exploiting the fact that the geometric property can be tested for directly. To this end, we develop an algorithm that takes PPI interaction data and embeds proteins into a low-dimensional Euclidean space, under the premise that connectivity information corresponds to Euclidean proximity, as in geometric-random graphs.We judge the sensitivity and specificity of the fit by computing the area under the Receiver Operator Characteristic (ROC) curve. The network embedding algorithm is based on multi-dimensional scaling, with the square root of the path length in a network playing the role of the Euclidean distance in the Euclidean space. The algorithm exploits sparsity for computational efficiency, and requires only a few sparse matrix multiplications, giving a complexity of O(N2) where N is the number of proteins.The algorithm has been verified in the sense that it successfully rediscovers the geometric structure in artificially constructed geometric networks, even when noise is added by re-wiring some links. Applying the algorithm to 19 publicly available PPI networks of various organisms indicated that: (a) geometric effects are present and (b) two-dimensional Euclidean space is generally as effective as higher dimensional Euclidean space for explaining the connectivity. Testing on a high-confidence yeast data set produced a very strong indication of geometric structure (area under the ROC curve of 0.89), with this network being essentially indistinguishable from a noisy geometric network. Overall, the results add support to the hypothesis that PPI networks have a geometric structure

    Fitting a geometric graph to a protein-protein interaction network

    Get PDF
    Finding a good network null model for protein-protein interaction (PPI) networks is a fundamental issue. Such a model would provide insights into the interplay between network structure and biological function as well as into evolution. Also, network (graph) models are used to guide biological experiments and discover new biological features. It has been proposed that geometric random graphs are a good model for PPI networks. In a geometric random graph, nodes correspond to uniformly randomly distributed points in a metric space and edges (links) exist between pairs of nodes for which the corresponding points in the metric space are close enough according to some distance norm. Computational experiments have revealed close matches between key topological properties of PPI networks and geometric random graph models. In this work, we push the comparison further by exploiting the fact that the geometric property can be tested for directly. To this end, we develop an algorithm that takes PPI interaction data and embeds proteins into a low-dimensional Euclidean space, under the premise that connectivity information corresponds to Euclidean proximity, as in geometric-random graphs.We judge the sensitivity and specificity of the fit by computing the area under the Receiver Operator Characteristic (ROC) curve. The network embedding algorithm is based on multi-dimensional scaling, with the square root of the path length in a network playing the role of the Euclidean distance in the Euclidean space. The algorithm exploits sparsity for computational efficiency, and requires only a few sparse matrix multiplications, giving a complexity of O(N2) where N is the number of proteins.The algorithm has been verified in the sense that it successfully rediscovers the geometric structure in artificially constructed geometric networks, even when noise is added by re-wiring some links. Applying the algorithm to 19 publicly available PPI networks of various organisms indicated that: (a) geometric effects are present and (b) two-dimensional Euclidean space is generally as effective as higher dimensional Euclidean space for explaining the connectivity. Testing on a high-confidence yeast data set produced a very strong indication of geometric structure (area under the ROC curve of 0.89), with this network being essentially indistinguishable from a noisy geometric network. Overall, the results add support to the hypothesis that PPI networks have a geometric structure

    THz packaging solution for low cost si-based 40 Gb/s wireless link system

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    This paper presents an innovative low-cost transmitter solution aimed at improving telecommunication networks capacities in order to support the massive data traffic growth. Sub-THz frequencies > 200 GHz are considered to target at least 40 Gb/s. The proposed transmitter consists of a Silicon Photonic integrated sub-THz source and an industrial antenna integrated in HDI organic packaging substrate. As these components were experimentally evaluated, a real-time error free wireless data transmission of 10 Gb/s was successfully achieved and an antenna gain of 5.5 dBi was measured in the broadside direction from 220 GHz to 240 GHz (8.7% relative bandwidth). With the addition of a low-cost dielectric lens, a gain of 17 dBi was reached.info:eu-repo/semantics/acceptedVersio

    Ground-based photometry of space-based transit detections: Photometric follow-up of the CoRoT mission

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    The motivation, techniques and performance of the ground-based photometric follow-up of transit detections by the CoRoT space mission are presented. Its principal raison d'\^{e}tre arises from the much higher spatial resolution of common ground-based telescopes in comparison to CoRoT's cameras. This allows the identification of many transit candidates as arising from eclipsing binaries that are contaminating CoRoT's lightcurves, even in low-amplitude transit events that cannot be detected with ground-based obervations. For the ground observations, 'on'-'off' photometry is now largely employed, in which only a short timeseries during a transit and a section outside a transit is observed and compared photometrically. CoRoT planet candidates' transits are being observed by a dedicated team with access to telescopes with sizes ranging from 0.2 to 2 m. As an example, the process that led to the rejection of contaminating eclipsing binaries near the host star of the Super-Earth planet CoRoT-7b is shown. Experiences and techniques from this work may also be useful for other transit-detection experiments, when the discovery instrument obtains data with a relatively low angular resolution.Comment: Accepted for the A&A special issue on CoRo
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