507 research outputs found

    Near-infrared identification of the counterpart to X1908+075: a new OB-supergiant X-ray binary

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    We report the near-infrared (IR) identification of the likely counterpart to X1908+075, a highly-absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant-neutron star binary systems. Our JHKs-band imaging of the field reveals the existence within the X-ray error boxes of a near-IR source consistent with an early-type star lying at d=7 kpc and suffering A(V)=16 mag of extinction, the latter value being in good agreement with the hydrogen column density derived from a modelling of the X-ray spectrum. Our follow-up, near-IR spectroscopic observations confirm the nature of this candidate and lead to a late O-type supergiant classification, thereby supporting the identification of a new Galactic OB-supergiant X-ray binary.Comment: Accepted for publication in MNRAS, 7 pages, 3 figure

    Regionalizing rainfall at very high resolution over la Réunion island using a regional climate model.

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    23 pagesInternational audienceRegional climate models (RCMs) should be evaluated with respect to their ability to downscale large-scale climate information to the local scales, which are sometimes strongly modulated by surface conditions. This is the case for La Reunion (southwest Indian Ocean) because of its island context and its complex topography. Large-scale atmospheric configurations such as tropical cyclones (TCs) may have an amplifying effect on local rainfall patterns that only a very high-resolution RCM, forced by the large scales and resolving finescale processes, may simulate properly. This paper documents the capability of the Weather Research and Forecasting Model (WRF) RCM to regionalize rainfall variability at very high resolution (680 m) over La Reunion island for daily to seasonal time scales and year-to-year differences. Two contrasted wet seasons (November-April) are selected: 2000-01 (abnormally dry) and 2004-05 (abnormally wet). WRF rainfall is compared to a dense network of rain gauge records interpolated onto the WRF grid through the regression-kriging (RK) technique. RK avoids the point-to-grid comparison issue, but produces imperfect estimates due to sampling, so its quality also needs to be tested. Seasonal rainfall amounts and contrasts produced by WRF are fairly realistic. At intraseasonal and daily time scales, differences to RK are more sizable. These differences are not easy to interpret in sectors where the rain gauge network is less dense and the quality of RK more uncertain, as over the eastern slopes of Piton de la Fournaise volcano where WRF seems to simulate more realistic rainfall than RK. Finally, the heavy rainfall associated with TC Ando on 6 January 2001, is documented. WRF shows weak disagreements with RK, indicating its capability to regionalize rainfall during extreme events

    Up-regulation of ryanodine receptor expression increases the calcium-induced calcium release and spontaneous calcium signals in cerebral arteries from hindlimb unloaded rats

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    Microgravity induces a redistribution of blood volume. Consequently, astronauts' body pressure is modified so that the upright blood pressure gradient is abolished, thereby inducing a modification in cerebral blood pressure. This effect is mimicked in the hindlimb unloaded rat model. After a duration of 8 days of unloading, Ca²⁺ signals activated by depolarization and inositol-1,4,5-trisphosphate intracellular release were increased in cerebral arteries. In the presence of ryanodine and thapsigargin, the depolarization-induced Ca²⁺ signals remained increased in hindlimb suspended animals, indicating that Ca²⁺ influx and Ca²⁺-induced Ca²⁺ release mechanism were both increased. Spontaneous Ca²⁺ waves and localized Ca²⁺ events were also investigated. Increases in both amplitude and frequency of spontaneous Ca²⁺ waves were measured in hindlimb suspension conditions. After pharmacological segregation of Ca²⁺ sparks and Ca²⁺ sparklets, their kinetic parameters were characterized. Hindlimb suspension induced an increase in the frequencies of both Ca²⁺ localized events, suggesting an increase of excitability. Labeling with bodipy compounds suggested that voltage-dependent Ca²⁺ channels and ryanodine receptor expressions were increased. Finally, the expression of the ryanodine receptor subtype 1 (RyR1) was increased in hindlimb unloading conditions. Taken together, these results suggest that RyR1 expression and voltage-dependent Ca²⁺ channels activity are the focal points of the regulation of Ca²⁺ signals activated by vasoconstriction in rat cerebral arteries with an increase of the voltage-dependent Ca²⁺ influx

    An improved method for isolation of microvascular endothelial cells from normal and inflamed human lung

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    Summary: Microvascular endothelial cells (MVEC), which differ from large vessel endothelial cells, have been isolated successfully from lungs of various species, including man. However, contamination by nonendothelial cells remains a major problem in spite of several technical improvements. In view of the organ specificity of MVEC, endothelial cells should be derived from the tissue involved in the diseases one wishes to study. Therefore, to investigate some of the immunopathological mechanisms leading to acute respiratory distress syndrome (ARDS), we have attempted to isolate lung MVEC from patients undergoing thoracic surgery for lung carcinoma and patients dying of ARDS. The method described here includes four main steps: (1) full digestion of pulmonary tissue with trypsin and collagenase, (2) aggregation of MVEC induced by human plasma, (3) Percoll density centrifugation, and (4) selection and transfer of MVEC after local digestion with trypsin/EDTA under light microscopy. Normal and ARDS-derived lung MVEC purified by this technique presented contact inhibition (i.e., grew in monolayer), and expressed classical endothelial markers, including von Willebrand factor (vWF), platelet endothelial cell adhesion molecule 1(PECAM-1, CD31), and transcripts for the angiogensin converting enzyme (ACE). The cells also formed capillarylike structures, took up high levels of acetylated low-density lipoprotein (Ac-LDL), and exhibited ELAM-1 inducibility in response to TNF. Contaminant cells, such as fibroblasts, smooth muscle cells, or pericytes, were easily recognized on the basis of morphology and were eliminated by selection of plasma-aggregated cells under light microscopy. The technique presented here allows one to study the specific involvement and contribution of pulmonary endothelium in various lung disease

    Massive Stars in the Gaia-ESO Survey

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    The Gaia-ESO Survey (GES) is an ambitious project to study the formation and evolution of the Milky Way and its stellar populations. It is led by Gerry Gilmore and Sofia Randich and includes about 350 Co-Investigators. During 300 nights (spread over 5 years) of order 10^5 Giraffe spectra and 10^4 UVES spectra will be taken. As part of the survey, about 13 clusters will be observed that were chosen specifically for their massive-star content. We report on the preliminary analysis of GES data from two such clusters: NGC 3293 and NGC 6705. We determine stellar parameters for the B-type stars in NGC 3293 and compare the A-type stars population between the two clusters. We also use a repeat observation to study binarity and use the radial velocity information to study cluster membership in NGC 3293. We also list our plans for future observations, which include the Carina nebula region

    Guest editorial: fatigue design and material defects

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    This issue of Fatigue and Fracture of Engineering Materials and Structures contains a collection of manuscripts presented at the Second International Symposium on Fatigue Design and Material Defects (FDMD II) held in Paris, France, on June 11 – 13, 2014 organized by the French Society for Metallurgy and Materials (SF2M) and the German Association for Materials Research and Testing (DVM)

    Sporadic and genetic forms of paediatric somatotropinoma: a retrospective analysis of seven cases and a review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Somatotropinoma, a pituitary adenoma characterised by excessive production of growth hormone (GH), is extremely rare in childhood. A genetic defect is evident in some cases; known genetic changes include: multiple endocrine neoplasia type 1 (MEN1<it>)</it>; Carney complex; McCune-Albright syndrome; and, more recently identified, aryl hydrocarbon receptor-interacting protein (AIP). We describe seven children with somatotropinoma with a special focus on the differences between genetic and sporadic forms.</p> <p>Methods</p> <p>Seven children who presented in our regional network between 1992 and 2008 were included in this retrospective analysis. First-type therapy was somatostatin (SMS) analogues or transsphenoidal surgery. Control was defined as when insulin-like growth factor-1 (IGF-1) levels were within the normal range for the patient's age at 6 months after therapy, associated with decreasing tumour volume.</p> <p>Results</p> <p>Patients were aged 5-17 years and the majority (n = 6) were male. Four patients had an identified genetic mutation (McCune-Albright syndrome: n = 1; MEN1: n = 1; AIP: n = 2); the remaining three cases were sporadic. Accelerated growth rate was reported as the first clinical sign in four patients. Five patients presented with macroadenoma; invasion was noted in four of them (sporadic: n = 1; genetic: n = 3). Six patients were treated with SMS analogues; normalisation of IGF-1 occurred in one patient who had a sporadic intrasellar macroadenoma. Multiple types of therapy were necessary in all patients with an identified genetic mutation (4 types: n = 1; 3 types: n = 2; 2 types: n = 1), whereas two of the three patients with sporadic somatotropinoma required only one type of therapy.</p> <p>Conclusions</p> <p>This is the first series that analyzes the therapeutic response of somatotropinoma in paediatric patients with identified genetic defects. We found that, in children, genetic somatotropinomas are more invasive than sporadic somatotropinomas. Furthermore, SMS analogues appear to be less effective for treating genetic somatotropinoma than sporadic somatotropinoma.</p

    Inhibition of bone turnover by milk intake in postmenopausal women

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    Increased postmenopausal bone turnover leads to bone loss and fragility fracture risk. In the absence of osteoporosis, risk preventive measures, particularly those modifying nutritional lifestyle, are appropriate. We tested the hypothesis that milk supplementation affects bone turnover related to biochemical markers in a direction that, in the long term, may be expected to reduce postmenopausal bone loss. Thirty healthy postmenopausal women aged 59·3 (sd 3·3) years were enrolled in a prospective crossover trial of 16 weeks. After a 4-week period of adaptation with diet providing 600mg calcium plus 300mg ingested as 250ml semi-skimmed milk, participants were maintained during 6 weeks under the same 600mg calcium diet and randomized to receive either 500ml semi-skimmed milk, thus providing a total of 1200mg calcium, or no milk supplement. In the next 6 weeks they were switched to the alternative regimen. At the end of the each period, i.e. after 4, 10 and 16 weeks, blood and urinary samples were collected. The changes in blood variables between the periods of 6 weeks without and with milk supplementation were: for parathyroid hormone, −3·2pg/ml (P=0·0054); for crosslinked telopeptide of type I collagen, −624pg/ml (P<0·0001); for propeptide of type I procollagen, −5·5ng/ml (P=0·0092); for osteocalcin, −2·8ng/ml (P=0·0014). In conclusion, a 6-week period of milk supplementation induced a decrease in several biochemical variables compatible with diminished bone turnover mediated by reduction in parathyroid hormone secretion. This nutritional approach to postmenopausal alteration in bone metabolism may be a valuable measure in the primary prevention of osteoporosi

    Advantages of 18F-FDG PET/CT imaging over modified Duke criteria and clinical presumption in patients with challenging suspicion of infective endocarditis

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    According to European Society of Cardiology guidelines (ESC2015) for infective endocarditis (IE) management, modified Duke criteria (mDC) are implemented with a degree of clinical suspicion degree, leading to grades such as possible or rejected IE despite a persisting high level of clinical suspicion. Herein, we evaluate th
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