9,105 research outputs found

    Poly[(R)-3-hydroxybutyrate] production under different salinity conditions by a novel Bacillus megaterium strain

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    Bacillus megaterium uyuni S29, isolated from the Bolivian salt lake Uyuni, displays a high capability to produce poly[(R)-hydroxybutyrate] (PHB) in industrial culture media. In order to analyze the influence of salt on biomass formation and PHB production, cultivations at different NaCl concentrations were carried out according to the salinity conditions of the habitats of the strain’s original isolation. In this preliminary report, the strain showed considerable adaptability to media of different salinity, obtaining the best results for both cellular growth and PHB production in media containing 45 g/L NaCl. The strain grew at 100 g/L NaCl and PHB production was observed even at high salt levels of 250 g/L without unwanted concurrent spore formation. Its tolerance to high salt concentrations together with auspicious PHB productivity makes this strain appealing not only for PHB production, but also for other biotechnological applications such as the treatment of salty wastewater; additional studies will be needed to further increase PHB productivity.Postprint (published version

    Novel method of severe plastic deformation - Continuous closed die forging: CP aluminum case study

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    There is a large number of methods for severe plastic deformation (SPD). Multidirectional forging (MDF) is probably one of the most easily scalable for industrial application. In general, two main conditions need to be fulfilled for successful SPD processing: constan t sample geometry and application of a quasi - hydrostatic pressure. The first condition is necessary for strain accumulation by repetitive deformation and the second one helps preventing cracking in the specimens with high accumulated strain. However, MDF i s not providing quasi - hydrostatic condition in the processed sample. This paper reports a novel method for severe plastic deformation, namely continuous close d die forging (CCDF), which fulfils both requirements for the successful deformation of samples to a very high accumulated strain. Commercially pure aluminum (1050) was processed to a total strain of 24 by CCDF. After processing, the microstructure was refined down to a mean grain size of 0. 78 µm . Tensile testing showed good mechanical properties: yiel d strength and ultimate tensile strength of the ultrafine - grained (UFG) aluminum were 180 and 226 MPa, respectively. Elongation to rupture was about 18%. The microstructure, microhardness and grain boundary statistics are discussed with regard to the high mechanical properties of the UFG aluminum processed by th is novel method.Peer ReviewedPostprint (author's final draft

    Acquired potential N-glycosylation sites within the tumor-specific immunoglobulin heavy chains of B-cell malignancies

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    Background and Objectives. Among B-cell malignancies, follicular lymphomas (FL) more frequently show acquired, potential N-glycosylation sites (AGS) within tumor-specific immunoglobulin. The aim of this study was to extend this observation and to evaluate the pattern of presentation of AGS within five different forms of B-cell lymphoma. Design and Methods. We sequenced the tumor-specific immunoglobulin heavy chain variable region fragment, including complementarity-determining regions 2 and 3, of forty-seven consecutive patients with a B-cell malignancy enrolled in idiotype vaccine clinical trials. This sequencing approach is known to allow the identification of most AGS. We then statistically analyzed differences in presentation pattern, in terms of tumor histology, immunoglobulin isotype, AGS location and amino acid composition. Results. All twenty-four FL cases presented with at least one AGS, whereas the vast majority of four B-cell lymphoma types other than FL did not. The non- FL group of tumors included four cases of Burkitt’s lymphoma, six of diffuse large cell lymphoma, seven mantle cell lymphomas and six small lymphocytic lymphomas. Most IgM-bearing follicular lymphoma cases featured their AGS within complementarity-determining region 2, as opposed to those bearing an IgG, which mostly displayed the AGS within complementarity- determining region 3. The vast majority of AGS located within either complementarity- determining region ended with a serine residue, whereas those located within framework regions mostly featured threonine as the last amino acid residue. Interpretation and Conclusions. In our series, all cases of FL had AGS within their tumor-specific immunoglobulin heavy chain variable regions. In contrast, most B-cell malignancies other than FL did not. Further studies are warranted in order to establish the possible meaning of these findings in terms of disease pathogenesis, their diagnostic value in doubtful cases and their potential implications for immunotherapy

    The NIKA instrument: results and perspectives towards a permanent KID based camera for the Pico Veleta observatory

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    The New IRAM KIDs Array (NIKA) is a pathfinder instrument devoted to millimetric astronomy. In 2009 it was the first multiplexed KID camera on the sky; currently it is installed at the focal plane of the IRAM 30-meters telescope at Pico Veleta (Spain). We present preliminary data from the last observational run and the ongoing developments devoted to the next NIKA-2 kilopixels camera, to be commissioned in 2015. We also report on the latest laboratory measurements, and recent improvements in detector cosmetics and read-out electronics. Furthermore, we describe a new acquisition strategy allowing us to improve the photometric accuracy, and the related automatic tuning procedure.Comment: 24th International Symposium on Space Terahertz Technology, ISSTT 2013, April 8 to 10, 2013, Groningen, the Netherland

    Non-parametric deprojection of NIKA SZ observations: Pressure distribution in the Planck-discovered cluster PSZ1 G045.85+57.71

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    The determination of the thermodynamic properties of clusters of galaxies at intermediate and high redshift can bring new insights into the formation of large-scale structures. It is essential for a robust calibration of the mass-observable scaling relations and their scatter, which are key ingredients for precise cosmology using cluster statistics. Here we illustrate an application of high resolution (<20(< 20 arcsec) thermal Sunyaev-Zel'dovich (tSZ) observations by probing the intracluster medium (ICM) of the \planck-discovered galaxy cluster \psz\ at redshift z=0.61z = 0.61, using tSZ data obtained with the NIKA camera, which is a dual-band (150 and 260~GHz) instrument operated at the IRAM 30-meter telescope. We deproject jointly NIKA and \planck\ data to extract the electronic pressure distribution from the cluster core (R0.02R500R \sim 0.02\, R_{500}) to its outskirts (R3R500R \sim 3\, R_{500}) non-parametrically for the first time at intermediate redshift. The constraints on the resulting pressure profile allow us to reduce the relative uncertainty on the integrated Compton parameter by a factor of two compared to the \planck\ value. Combining the tSZ data and the deprojected electronic density profile from \xmm\ allows us to undertake a hydrostatic mass analysis, for which we study the impact of a spherical model assumption on the total mass estimate. We also investigate the radial temperature and entropy distributions. These data indicate that \psz\ is a massive (M5005.5×1014M_{500} \sim 5.5 \times 10^{14} M_{\odot}) cool-core cluster. This work is part of a pilot study aiming at optimizing the treatment of the NIKA2 tSZ large program dedicated to the follow-up of SZ-discovered clusters at intermediate and high redshifts. (abridged)Comment: 16 pages, 10 figure

    The NIKA2 instrument, a dual-band kilopixel KID array for millimetric astronomy

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    NIKA2 (New IRAM KID Array 2) is a camera dedicated to millimeter wave astronomy based upon kilopixel arrays of Kinetic Inductance Detectors (KID). The pathfinder instrument, NIKA, has already shown state-of-the-art detector performance. NIKA2 builds upon this experience but goes one step further, increasing the total pixel count by a factor \sim10 while maintaining the same per pixel performance. For the next decade, this camera will be the resident photometric instrument of the Institut de Radio Astronomie Millimetrique (IRAM) 30m telescope in Sierra Nevada (Spain). In this paper we give an overview of the main components of NIKA2, and describe the achieved detector performance. The camera has been permanently installed at the IRAM 30m telescope in October 2015. It will be made accessible to the scientific community at the end of 2016, after a one-year commissioning period. When this happens, NIKA2 will become a fundamental tool for astronomers worldwide.Comment: Proceedings of the 16th Low Temperature Detectors workshop. To be published in the Journal of Low Temperature Physics. 8 pages, 4 figures, 1 tabl

    Latest NIKA results and the NIKA-2 project

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    NIKA (New IRAM KID Arrays) is a dual-band imaging instrument installed at the IRAM (Institut de RadioAstronomie Millimetrique) 30-meter telescope at Pico Veleta (Spain). Two distinct Kinetic Inductance Detectors (KID) focal planes allow the camera to simultaneously image a field-of-view of about 2 arc-min in the bands 125 to 175 GHz (150 GHz) and 200 to 280 GHz (240 GHz). The sensitivity and stability achieved during the last commissioning Run in June 2013 allows opening the instrument to general observers. We report here the latest results, in particular in terms of sensitivity, now comparable to the state-of-the-art Transition Edge Sensors (TES) bolometers, relative and absolute photometry. We describe briefly the next generation NIKA-2 instrument, selected by IRAM to occupy, from 2015, the continuum imager/polarimeter slot at the 30-m telescope.Comment: Proceedings of Low Temperature Detectors 15 (LTD-15), Pasadena, June 201

    Detection of the tSZ effect with the NIKA camera

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    We present the first detection of the thermal Sunyaev-Zel'dovich (tSZ) effect from a cluster of galaxies performed with a KIDs (Kinetic Inductance Detectors) based instrument. The tSZ effect is a distortion of the black body CMB (Cosmic Microwave Background) spectrum produced by the inverse Compton interaction of CMB photons with the hot electrons of the ionized intra-cluster medium. The massive, intermediate redshift cluster RX J1347.5-1145 has been observed using NIKA (New IRAM KIDs arrays), a dual-band (140 and 240 GHz) mm-wave imaging camera, which exploits two arrays of hundreds of KIDs: the resonant frequencies of the superconducting resonators are shifted by mm-wave photons absorption. This tSZ cluster observation demonstrates the potential of the next generation NIKA2 instrument, being developed for the 30m telescope of IRAM, at Pico Veleta (Spain). NIKA2 will have 1000 detectors at 140GHz and 2x2000 detectors at 240GHz, providing in that band also a measurement of the linear polarization. NIKA2 will be commissioned in 2015.Comment: SF2A Proceedings 201

    High-resolution tSZ cartography of clusters of galaxies with NIKA at the IRAM 30-m telescope

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    The thermal Sunyaev-Zeldovich effect (tSZ) is a powerful probe to study clusters of galaxies and is complementary with respect to X-ray, lensing or optical observations. Previous arcmin resolution tSZ observations ({\it e.g.} SPT, ACT and Planck) only enabled detailed studies of the intra-cluster medium morphology for low redshift clusters (z<0.2z < 0.2). Thus, the development of precision cosmology with clusters requires high angular resolution observations to extend the understanding of galaxy cluster towards high redshift. NIKA2 is a wide-field (6.5 arcmin field of view) dual-band camera, operated at 100 mK100 \ {\rm mK} and containing 3300\sim 3300 KID (Kinetic Inductance Detectors), designed to observe the millimeter sky at 150 and 260 GHz, with an angular resolution of 18 and 12 arcsec respectively. The NIKA2 camera has been installed on the IRAM 30-m telescope (Pico Veleta, Spain) in September 2015. The NIKA2 tSZ observation program will allow us to observe a large sample of clusters (50) at redshift ranging between 0.5 and 1. As a pathfinder for NIKA2, several clusters of galaxies have been observed at the IRAM 30-m telescope with the NIKA prototype to cover the various configurations and observation conditions expected for NIKA2.Comment: Proceedings of the 28th Texas Symposium on Relativistic Astrophysics, Geneva, Switzerland, December 13-18, 201
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