5,936 research outputs found

    Curie temperature enhancement of electron doped Sr2_2FeMoO6_6 perovskites studied by photoemission spectroscopy

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    We report here on the electronic structure of electron-doped half-metallic ferromagnetic perovskites such Sr2x_{2-x}Lax_xFeMoO6_6 (xx=0-0.6) as obtained from high-resolved valence-band photoemission spectroscopy (PES). By comparing the PES spectra with band structure calculations, a distinctive peak at the Fermi level (EF_F) with predominantly (Fe+Mo) t2g_{2g}^\downarrow character has been evidenced for all samples, irrespectively of the xx values investigated. Moreover, we show that the electron doping due to the La substitution provides selectively delocalized carriers to the t2g_{2g}^\downarrow metallic spin channel. Consequently, a gradual rising of the density of states at the EF_F has been observed as a function of the La doping. By changing the incoming photon energy we have shown that electron doping mainly rises the density of states of Mo parentage. These findings provide fundamental clues for understanding the origin of ferromagnetism in these oxides and shall be of relevance for tailoring oxides having still higher TC_C

    New compound sets identified from high throughput phenotypic screening against three kinetoplastid parasites:an open resource

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    Using whole-cell phenotypic assays, the GlaxoSmithKline high-throughput screening (HTS) diversity set of 1.8 million compounds was screened against the three kinetoplastids most relevant to human disease, i.e. Leishmania donovani, Trypanosoma cruzi and Trypanosoma brucei. Secondary confirmatory and orthogonal intracellular anti-parasiticidal assays were conducted, and the potential for non-specific cytotoxicity determined. Hit compounds were chemically clustered and triaged for desirable physicochemical properties. The hypothetical biological target space covered by these diversity sets was investigated through bioinformatics methodologies. Consequently, three anti-kinetoplastid chemical boxes of ~200 compounds each were assembled. Functional analyses of these compounds suggest a wide array of potential modes of action against kinetoplastid kinases, proteases and cytochromes as well as potential host–pathogen targets. This is the first published parallel high throughput screening of a pharma compound collection against kinetoplastids. The compound sets are provided as an open resource for future lead discovery programs, and to address important research questions.The support and funding of Tres Cantos Open Lab Foundation is gratefully acknowledgedPeer reviewe

    Clinical impact of acute kidney injury on short- and long-term outcomes after transcatheter aortic valve implantation with the CoreValve prosthesis

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    AbstractBackgroundAcute kidney injury (AKI) after cardiac surgery is associated with increased mortality, but few data exist on the occurrence and clinical impact of AKI associated with transcatheter aortic valve implantation (TAVI). The objective of this study was to determine the incidence and prognosis of AKI after percutaneous implantation of the CoreValve® (Medtronic, Minneapolis, MN, USA) prosthesis.MethodsA total of 357 patients with severe aortic stenosis and 9 patients with pure native aortic regurgitation were treated with the CoreValve prosthesis. AKI was defined according to Valve Academic Research Consortium criteria as the absolute increase in serum creatinine ≥0.3mg/dl at 72h post percutaneous procedure.ResultsAKI was identified in 58 patients (15.8%), none of whom required renal replacement therapy. In patients with AKI, the mortality at 30 days was 13.5% compared with 1.6% of patients without AKI, [odds ratio (OR)=12.2 (95% CI 3.53–41.9); p<0.001] and total mortality after a mean of 26.2±17 months was 29.3% vs. 14.9% [OR=2.36 (95% CI 1.23–4.51), p=0.008]. In the multivariate analysis, AKI was an independent predictor of cumulative total mortality [hazard ratio=2.151, (95% CI from 1.169 to 3.957), p=0.014].ConclusionsThe deterioration of renal function in patients undergoing TAVI with the CoreValve prosthesis is a serious and frequent complication. The occurrence of AKI was associated with increased early mortality and was also a predictor of worse outcomes in follow-up

    The IR Luminosity Functions of Rich Clusters

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    We present MIPS observations of the cluster A3266. About 100 spectroscopic cluster members have been detected at 24 micron. The IR luminosity function in A3266 is very similar to that in the Coma cluster down to the detection limit L_IR~10^43 ergs/s, suggesting a universal form of the bright end IR LF for local rich clusters with M~10^15 M_sun. The shape of the bright end of the A3266-Coma composite IR LF is not significantly different from that of nearby field galaxies, but the fraction of IR-bright galaxies (SFR > 0.2M_sun/yr) in both clusters increases with cluster-centric radius. The decrease of the blue galaxy fraction toward the high density cores only accounts for part of the trend; the fraction of red galaxies with moderate SFRs (0.2 < SFR < 1 M_sun/yr) also decreases with increasing galaxy density. These results suggest that for the IR bright galaxies, nearby rich clusters are distinguished from the field by a lower star-forming galaxy fraction, but not by a change in L*_IR. The composite IR LF of Coma and A3266 shows strong evolution when compared with the composite IR LF of two z~0.8 clusters, MS 1054 and RX J0152, with L*_IR \propto (1+z)^{3.2+/-0.7},Phi*_IR \propto (1+z)^{1.7+/-1.0}. This L*_IR evolution is indistinguishable from that in the field, and the Phi*_IR evolution is stronger, but still consistent with that in the field. The similarity of the evolution of bright-end IR LF in very different cluster and field environments suggests either this evolution is driven by the mechanism that works in both environments, or clusters continually replenish their star-forming galaxies from the field, yielding an evolution in the IR LF that is similar to the field. The mass-normalized integrated star formation rates (SFRs) of clusters within 0.5R_200 also evolve strongly with redshift, as (1+z)^5.3.Comment: 15 pages, 8 figures, 1 table, accepted by Ap

    Newly impaired glucose metabolism and prognosis after percutaneous revascularization

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    Background: Clinical practice guidelines recommend ad hoc screening of diabetes in patients admitted for macrovascular disease; however, these recommendations are rarely followed in real practice. This study was undertaken to assess whether impaired glucose metabolism, newly diagnosed after percutaneous coronary intervention (PCI) or known diabetes, provides prognostic information. Methods: We studied 374 patients who underwent PCI. An oral glucose tolerance test was carried out in the known non-diabetic patients with fasting glucose &lt; 7 mmol/L. Results: Eighty-one percent of the patients presented impaired glucose metabolism, from which 35.3% were previously diagnosed with diabetics, 21.4% were newly detected diabetics, and 24.3% were pre-diabetics. After a mean follow-up of 35.8 ± 13.4 months, only a known history of diabetes was an independent predictor of revascularization (OR = 2.03, p = 0.025), non-fatal acute myocardial infarction (OR = 2.70, p = 0.029) and readmission due to heart failure during the follow-up (OR = 3.82, p = 0.022). Conclusions: Screening for impaired glucose metabolism after PCI permits the detection of a high proportion of patients with abnormal glucose regulations. However, previously known diabetes remains the only independent predictor of cardiovascular events in the follow-up.

    Hsp90 orchestrates transcriptional regulation by Hsf1 and cell wall remodelling by MAPK signalling during thermal adaptation in a pathogenic yeast

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    Acknowledgments We thank Rebecca Shapiro for creating CaLC1819, CaLC1855 and CaLC1875, Gillian Milne for help with EM, Aaron Mitchell for generously providing the transposon insertion mutant library, Jesus Pla for generously providing the hog1 hst7 mutant, and Cathy Collins for technical assistance.Peer reviewedPublisher PD

    The VVV Templates Project. Towards an Automated Classification of VVV Light-Curves. I. Building a database of stellar variability in the near-infrared

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    Context. The Vista Variables in the V\'ia L\'actea (VVV) ESO Public Survey is a variability survey of the Milky Way bulge and an adjacent section of the disk carried out from 2010 on ESO Visible and Infrared Survey Telescope for Astronomy (VISTA). VVV will eventually deliver a deep near-IR atlas with photometry and positions in five passbands (ZYJHK_S) and a catalogue of 1-10 million variable point sources - mostly unknown - which require classifications. Aims. The main goal of the VVV Templates Project, that we introduce in this work, is to develop and test the machine-learning algorithms for the automated classification of the VVV light-curves. As VVV is the first massive, multi-epoch survey of stellar variability in the near-infrared, the template light-curves that are required for training the classification algorithms are not available. In the first paper of the series we describe the construction of this comprehensive database of infrared stellar variability. Methods. First we performed a systematic search in the literature and public data archives, second, we coordinated a worldwide observational campaign, and third we exploited the VVV variability database itself on (optically) well-known stars to gather high-quality infrared light-curves of several hundreds of variable stars. Results. We have now collected a significant (and still increasing) number of infrared template light-curves. This database will be used as a training-set for the machine-learning algorithms that will automatically classify the light-curves produced by VVV. The results of such an automated classification will be covered in forthcoming papers of the series.Comment: 12 pages, 16 figures, 3 tables, accepted for publication in A&A. Most of the data are now accessible through http://www.vvvtemplates.org
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