13,083 research outputs found

    Study of X52 steel in seawater with biocides under turbulent flow conditions

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    This work presents the corrosion study of the API X52 pipeline steel immersed in seawater without biocide and with 0,25, 0,5 and 0,75 ppm of biocide, under static and dynamic (turbulent flow) conditions at room temperature and atmospheric pressure. The total exposure time of the steel sample in test solution was 24h. In order to control the hydrodynamic conditions, a rotating cylinder electrode(RCE) was used. The rotation speed was 1000 RPM. The steel samples were immersed in the test solution, then, an electrochemical corrosion study using linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and polarization curves (PC) was made. In the superficial analysis of the steel samples, a scanning electronic microscopy was used. The results of the electrochemical study shown that the corrosion rate is higher under turbulent flow conditions than static conditions, and as the biocide concentration increased in the test solution, the corrosion rate decreased. A localized corrosion type was found in all the samples tested

    The course of the cystic artery during laparoscopic cholecystectomy

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    Proper recognition of the particular structures that form the triangle of Calot is essential for the proper and safe performance of laparoscopic cholecystectomy. Proper recognition, ligation, and cut of the cystic duct and cystic artery with branches (dorsal and ventral) remain an integral condition for the removal of the gallbladder. Calot’s triangle, as an orientation structure, determines the most common location of the cystic artery. The triangle of Calot is one of the most variable regions of the abdomen in terms of anatomy. The aim of this study was to evaluate how important for surgery is the detailed anatomical recognition of the main branches of the cystic artery in Calot’s triangle during laparoscopic cholecystectomy. Relations of the main branches of the cystic artery were evaluated in 88 patients that underwent laparoscopic cholecystectomy at the Department of General Surgery of the District Specialistic Hospital of Lublin. The anatomical relations of cystic duct and artery were classified into typical and variant types. Significantly more frequently variants of cystic artery were observed in women. However, the time of the procedure was not significantly related with the type of cystic artery

    An XMM-Newton and INTEGRAL view on the hard state of EXO 1745-248 during its 2015 outburst

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    CONTEXT - Transient low-mass X-ray binaries (LMXBs) often show outbursts lasting typically a few-weeks and characterized by a high X-ray luminosity (Lx≈1036−1038L_{x} \approx 10^{36}-10^{38} erg/sec), while for most of the time they are found in X-ray quiescence (LX≈1031−1033L_X\approx10^{31} -10^{33} erg/sec). EXO 1745-248 is one of them. AIMS - The broad-band coverage, and the sensitivity of instrument on board of {\xmm} and {\igr}, offers the opportunity to characterize the hard X-ray spectrum during {\exo} outburst. METHODS - In this paper we report on quasi-simultaneous {\xmm} and {\igr} observations of the X-ray transient {\exo} located in the globular cluster Terzan 5, performed ten days after the beginning of the outburst (on 2015 March 16th) shown by the source between March and June 2015. The source was caught in a hard state, emitting a 0.8-100 keV luminosity of ≃1037\simeq10^{37}~{\lumcgs}. RESULTS - The spectral continuum was dominated by thermal Comptonization of seed photons with temperature kTin≃1.3kT_{in}\simeq1.3 keV, by a cloud with moderate optical depth τ≃2\tau\simeq2 and electron temperature kTe≃40kT_e\simeq 40 keV. A weaker soft thermal component at temperature kTth≃0.6kT_{th}\simeq0.6--0.7 keV and compatible with a fraction of the neutron star radius was also detected. A rich emission line spectrum was observed by the EPIC-pn on-board {\xmm}; features at energies compatible with K-α\alpha transitions of ionized sulfur, argon, calcium and iron were detected, with a broadness compatible with either thermal Compton broadening or Doppler broadening in the inner parts of an accretion disk truncated at 20±620\pm6 gravitational radii from the neutron star. Strikingly, at least one narrow emission line ascribed to neutral or mildly ionized iron is needed to model the prominent emission complex detected between 5.5 and 7.5 keV. (Abridged)Comment: 14 pages, 6 figure, 2 tables. Accepted for publication on A&A (21/03/2017

    Ultrasound intensification of Ferrochelatase extraction from pork liver as a strategy to improve ZINC-protoporphyrin formation

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    [EN] The enzyme Ferrochelatase (FeCH), which is naturally present in pork liver, catalyses the formation of Zincprotoporphyrin (ZnPP), a natural pigment responsible for the typical color of dry-cured Italian Parma ham. The aim of this study was to evaluate the feasibility of using high power ultrasound in continuous and pulsed modes to intensify the extraction of the enzyme FeCH from pork liver. US application during FeCH extraction led to an improved enzymatic activity and further increase in the formation of ZnPP. The optimal condition tested was that of 1 min in continuous US application, in which time the enzymatic activity increased by 33.3 % compared to conventional extraction (30 min). Pulsed US application required 5 min treatments to observe a significant intensification effect. Therefore, ultrasound is a potentially feasible technique as it increases the catalytic activity of FeCH and saves time compared to the conventional extraction methodThe authors acknowledge the financial support from the "Ministerio de Economia y Competitividad (MINECO) and Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA)" in Spain (Project RTA2017-00024-C04-03). The authors acknowledge the contribution of the undergraduate student Jose V. Pedrero-Gonzalez to the experimental work.Abril-Gisbert, B.; Sanchez-Torres, E.; Bou, R.; Garcia-Perez, J.; Benedito Fort, JJ. (2021). Ultrasound intensification of Ferrochelatase extraction from pork liver as a strategy to improve ZINC-protoporphyrin formation. Ultrasonics Sonochemistry. 78:1-7. https://doi.org/10.1016/j.ultsonch.2021.105703S177

    Diet-Induced Swine Model with Obesity/Leptin Resistance for the Study of Metabolic Syndrome and Type 2 Diabetes

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    The objective of the present study was to determine the suitability of a swine breed with leptin resistance and predisposition to obesity (the Iberian pig) as model for studies on metabolic syndrome and type 2 diabetes. Thus, six Iberian sows had ad libitum access to food enriched with saturated fat (SFAD group; food consumption was estimated to be 4.5 kg/animal/day) whilst four females acted as controls and were fed with 2 kg/animal/day of a commercial maintenance diet. After three months of differential feeding, SFAD animals developed central obesity, dyslipidemia, insulin resistance and impaired glucose tolerance, and elevated blood pressure; the five parameters associated with the metabolic syndrome. Thus, the current study characterizes the Iberian pig as a robust, amenable, and reliable translational model for studies on nutrition-associated diseases

    The Low Redshift survey at Calar Alto (LoRCA)

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    The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information about dark energy, it is necessary to measure a standard ruler in the local, z<0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4\% and 1.2\% using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy.Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto (LoRCA), to observe spectroscopically about 200,000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website: http://lorca-survey.ft.uam.es

    The Low Redshift survey at Calar Alto (LoRCA)

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    The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information about dark energy, it is necessary to measure a standard ruler in the local, z<0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 Mpc/h wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34,000 sq. deg.), i.e. a K(2MASS)<14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4\% and 1.2\% using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy.Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto (LoRCA), to observe spectroscopically about 200,000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.Comment: 15 pages. Accepted in MNRAS. Please visit our website: http://lorca-survey.ft.uam.es

    Spectroscopic classification of X-ray sources in the Galactic Bulge Survey

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    We present the classification of 26 optical counterparts to X-ray sources discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and spectroscopic observations to classify the X-ray sources based on their multi-wavelength properties. We find a variety of source classes, spanning different phases of stellar/binary evolution. We classify CX21 as a quiescent cataclysmic variable (CV) below the period gap, and CX118 as a high accretion rate (nova-like) CV. CXB12 displays excess UV emission, and could contain a compact object with a giant star companion, making it a candidate symbiotic binary or quiescent low mass X-ray binary (although other scenarios cannot be ruled out). CXB34 is a magnetic CV (polar) that shows photometric evidence for a change in accretion state. The magnetic classification is based on the detection of X-ray pulsations with a period of 81 ±\pm 2 min. CXB42 is identified as a young stellar object, namely a weak-lined T Tauri star exhibiting (to date unexplained) UX Ori-like photometric variability. The optical spectrum of CXB43 contains two (resolved) unidentified double-peaked emission lines. No known scenario, such as an AGN or symbiotic binary, can easily explain its characteristics. We additionally classify 20 objects as likely active stars based on optical spectroscopy, their X-ray to optical flux ratios and photometric variability. In 4 cases we identify the sources as binary stars.Comment: Accepted for publication in MNRA
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