2,604 research outputs found

    Preliminary study of kaonic deuterium X-rays by the SIDDHARTA experiment at DAFNE

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    The study of the KbarN system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. At the DAFNE electron-positron collider of Laboratori Nazionali di Frascati we studied kaonic atoms with Z=1 and Z=2, taking advantage of the low-energy charged kaons from Phi-mesons decaying nearly at rest. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width of the lowest experimentally accessible level (1s for H and D and 2p for He). Shift and width are connected to the real and imaginary part of the scattering length. To disentangle the isospin dependent scattering lengths of the antikaon-nucleon interaction, measurements of Kp and of Kd are needed. We report here on an exploratory deuterium measurement, from which a limit for the yield of the K-series transitions was derived: Y(K_tot)<0.0143 and Y(K_alpha)<0.0039 (CL 90%). Also, the upcoming SIDDHARTA-2 kaonic deuterium experiment is introduced.Comment: Accepted by Nuclear Physics

    X-ray transition yields of low-Z kaonic atoms produced in Kapton

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    The X-ray transition yields of kaonic atoms produced in Kapton polyimide (C22H10N2O5) were measured for the first time in the SIDDHARTA experiment. X-ray yields of the kaonic atoms with low atomic numbers (Z = 6, 7, and 8) and transitions with high principal quantum numbers (n = 5-8) were determined. The relative yield ratios of the successive transitions and those of carbon-to-nitrogen (C:N) and carbon-to-oxygen (C:O) were also determined. These X-ray yields provide important information for understanding the capture ratios and cascade mechanisms of kaonic atoms produced in a compound material, such as Kapton.Comment: Accepted in Nucl. Phys. A (2013

    First measurement of kaonic helium-3 X-rays

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    The first observation of the kaonic 3He 3d - 2p transition was made using slow K- mesons stopped in a gaseous 3He target. The kaonic atom X-rays were detected with large-area silicon drift detectors using the timing information of the K+K- pairs of phi-meson decays produced by the DAFNE e+e- collider. The strong interaction shift of the kaonic 3He 2p state was determined to be -2+-2 (stat)+-4 (syst) eV.Comment: Accepted for publication in Phys. Lett.

    RDFauthor: Employing RDFa for Collaborative Knowledge Engineering

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    A New Measurement of Kaonic Hydrogen X rays

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    The KˉN\bar{K}N system at threshold is a sensitive testing ground for low energy QCD, especially for the explicit chiral symmetry breaking. Therefore, we have measured the KK-series x rays of kaonic hydrogen atoms at the DAΦ\PhiNE electron-positron collider of Laboratori Nazionali di Frascati, and have determined the most precise values of the strong-interaction energy-level shift and width of the 1s1s atomic state. As x-ray detectors, we used large-area silicon drift detectors having excellent energy and timing resolution, which were developed especially for the SIDDHARTA experiment. The shift and width were determined to be ϵ1s=283±36±6(syst)\epsilon_{1s} = -283 \pm 36 \pm 6 {(syst)} eV and Γ1s=541±89(stat)±22(syst)\Gamma_{1s} = 541 \pm 89 {(stat)} \pm 22 {(syst)} eV, respectively. The new values will provide vital constraints on the theoretical description of the low-energy KˉN\bar{K}N interaction.Comment: 5 figures, submitted to Physics Letters

    Removal of xenoantigenic glycosylation patterns from porcine pulmonary heart valve matrices is dependent of the applied decellularization method

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    Department of Cardiac-, Thoracic-, Transplantation and Vascular Surgery, Hannover Medical School, Hannover Germany and Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany, The 6th International Medical Congress for Students and Young Doctors, May 12-14, 2016Introduction: Matrix guided tissue regeneration (GTR) based on allogeneic decellularized matrices has been shown as an overall convincing method for heart valve replacement. Nevertheless, a substantial donor shortage prevents an unlimited clinical application of human GTR-valves. Utilization of porcine decellularized heart valve matrices could offer a possible solution for overcoming this considerable limitation. In the past, implantation of xenogeneic valve tissues considered to be acellularinto human recipients, however, mostly lead to severe immune responses usually ending up into graft rejection. This study addresses the question whether potential xenoantigenic glycosylation of extracellular matrix components, like the major xenoantigen α-Gal, which served as model epitope for this study, can be removed by adjusted decellularization procedures. Materials and methods: Fresh porcine pulmonary heart valve conduits were decellularized by application of different detergent- and enzyme-based decellularization protocols. Subsequent cleavage of remaining matrix-related α-Gal epitopes was performed by enzymatic deglycosylation treatment on matrix samples of each decellularization group. Resulting tissues, mainly composed from insoluble extracellular matrix proteins, were afterwards divided into the relevant sections pulmonary artery wall specimens and pulmonary valve leaflets, frozen in liquid nitrogen, minced and finally solubilized by protease digestion. Evaluation of thus prepared solutions regarding to α-Gal contents was finally performed using a novel designed lectin-based immunoblot technique. Discussion results: Sole decellularization lead to significant removal of α-Gal, substantial varying in strong dependency to applied protocols between 30 to 50% compared to α-Gal contents of porcine native control tissues. An additional decrease of residual α-Gal in a range of another 15 to 30% was achievable by additional α-Galactosidase treatment. Combining decellularization and subsequent enzymatic digestion resulted in reductions of matrix related α-Gal contents down to levels, which could be measured for respective pulmonary valve tissues of α-Gal-KnockOut pigs. Conclusion: Residual xenoantigenic carbohydrates are detectable on insoluble matrix components of porcine pulmonary heart valves, substantially varying dependent on applied decellularization protocols. Combined with glycolytic digestions, remaining glycosylation contents are reducible to background levels. Impacts of these novel insights have to be evaluated in further in vitro as well as in vivo studies

    Cercetări privind entomofauna de coleoptere (coleoptera) din unele culturi agricole din N-E Moldovei

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    The purpose of these research is to identify the useful entomofauna from the agricultural crops which have been taken for the study: maize and cabbage. The researches were carried out in the Adamachi station which belongs to “Ion Ionescu de la Brad” University of Iasi, Romania. The biological material was sampled by means of the Barber soil traps from 3rd of June until 13th of September 2016. In total, 15 samples were made for every crop. The traps were placed every five in a row. To prevent the maceration of insects, a conservative liquid was used (water+ washing powder) in proportion of 16%. After finishing the experiments, the insects were bringing to the laboratory of Entomology in order to be counted and determined. From the Coleoptera order, the most dominant species are:-within the crop of maize: Amara aenea (Carabidae)-5 samples; Coccinella septempunctata (Coccinellidae)-15 samples;-within the crop of cabbage:Brachinus crepitans(Carabidae)-9 samples

    CONGAS: a collaborative ontology development framework based on Named GrAphS

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    The process of ontology development involves a range of skills and know-how often requiring team work of different people, each of them with his own way of contributing to the definition and formalization of the domain representation. For this reason, collaborative development is an important feature for ontology editing tools, and should take into account the different characteristics of team participants, provide them with a dedicated working environment allowing to express their ideas and creativity, still protecting integrity of the shared work. In this paper we present CONGAS, a collaborative version of the Knowledge Management and Acquisition platform Semantic Turkey which, exploiting the potentialities brought by recent introduction of context management into RDF triple graphs, offers a collaborative environment where proposals for ontology evolution can emerge and coexist, be evaluated by team users, trusted across different perspectives and eventually converged into the main development stream

    Kaonic hydrogen X-ray measurement in SIDDHARTA

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    Kaonic hydrogen atoms provide a unique laboratory to probe the kaon-nucleon strong interaction at the energy threshold, allowing an investigation of the interplay between spontaneous and explicit chiral symmetry breaking in low-energy QCD. The SIDDHARTA Collaboration has measured the KK-series X rays of kaonic hydrogen atoms at the DAΦ\PhiNE electron-positron collider of Laboratori Nazionali di Frascati, and has determined the most precise values of the strong-interaction induced shift and width of the 1s1s atomic energy level. This result provides vital constraints on the theoretical description of the low-energy KˉN\bar{K}N interaction.Comment: 11 pages, 7 figures, Nuclear Physics A (in press) Special Issue on Strangeness Nuclear Physic
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