313 research outputs found

    The relation between mass and concentration in X-ray galaxy clusters at high redshift

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    Galaxy clusters are the most recent, gravitationally-bound products of the hierarchical mass accretion over cosmological scales. How the mass is concentrated is predicted to correlate with the total mass in the cluster's halo, with systems at higher mass being less concentrated at given redshift and for any given mass, systems with lower concentration are found at higher redshifts. Through a spatial and spectral X-ray analysis, we reconstruct the total mass profile of 47 galaxy clusters observed with Chandra in the redshift range 0.4<z<1.20.4<z<1.2, selected to have no major mergers, to investigate the relation between the mass and the dark matter concentration, and the evolution of this relation with redshift. The sample in exam is the largest one investigated so far at z>0.4z>0.4, and is well suited to provide the first constraint on the concentration--mass relation at z>0.7z>0.7 from X-ray analysis. Under the assumptions that the distribution of the X-ray emitting gas is spherically symmetric and in hydrostatic equilibrium, we combine the deprojected gas density and spectral temperature profiles through the hydrostatic equilibrium equation to recover the parameters that describe a NFW total mass distribution. The comparison with results from weak lensing analysis reveals a very good agreement both for masses and concentrations. Uncertainties are however too large to make any robust conclusion on the hydrostatic bias of these systems. The relation is well described by the form c∝MB(1+z)Cc \propto M^B (1+z)^C, with B=−0.50±0.20B=-0.50 \pm 0.20, C=0.12±0.61C=0.12 \pm 0.61 (at 68.3\% confidence), it is slightly steeper than the one predicted by numerical simulations (B∌−0.1B\sim-0.1) and does not show any evident redshift evolution. We obtain the first constraints on the properties of the concentration--mass relation at z>0.7z > 0.7 from X-ray data, showing a reasonable good agreement with recent numerical predictions.Comment: A&A accepted, 18 pages, 13 figures, 1 Appendi

    Neurobiology of Pain in Children: An Overview

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    The evaluation of pain in the newborn and the infant is difficult because pain is mainly a subjective phenomenon. Until a few years ago, several myths persisted. First, the myth that children, especially infants, do not feel pain the way adults do, therefore there is no untoward consequences for them. Second, lack of assessment and reassessment for the presence of pain. Third, misunderstanding of how to conceptualise and quantify a subjective experience. Fourth, lack of knowledge of pain treatment. Fifth, the notion that addressing pain in children takes too much time and effort, in ultimate analysis resulting in wasting time. Sixth, fears of hidden -and not easy to diagnose or prevent- adverse effects of analgesic medications, including respiratory depression and addiction. Finally, from a conceptual point of view, high thresholds of pain in neonates and infants were considered to be present by natural character, and useful in protecting infant from pain during birth and transit through the narrow vaginal channel

    LSD1 mediates MYCN control of epithelial-mesenchymal transition through silencing of metastatic suppressor NDRG1 gene

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    Neuroblastoma (NB) with MYCN amplification is a highly aggressive and metastatic tumor in children. The high recurrence rate and resistance of NB cells to drugs urgently demands a better therapy for this disease. We have recently found that MYCN interacts with the lysine-specific demethylase 1 (LSD1), a histone modifier that participates in key aspects of gene transcription. In cancer cells, LSD1 contributes to the genetic reprogramming that underlies to Epithelial-Mesenchymal Transition (EMT) and tumor metastasis. Here, we show that LSD1 affects motility and invasiveness of NB cells by modulating the transcription of the metastasis suppressor NDRG1 (N-Myc Downstream-Regulated Gene 1). At mechanistic level, we found that LSD1 co-localizes with MYCN at the promoter region of the NDRG1 gene and inhibits its expression. Pharmacological inhibition of LSD1 relieves repression of NDRG1 by MYCN and affects motility and invasiveness of NB cells. These effects were reversed by overexpressing NDRG1. In NB tissues, high levels of LSD1 correlate with low levels of NDRG1 and reduced patients survival. Collectively, our findings elucidate a mechanism of how MYCN/LSD1 control motility and invasiveness of NB cells through transcription regulation of NDRG1 expression and suggest that pharmacological targeting of LSD1 represents a valuable approach for NB therapy

    Aspetti igienico-sanitari in ambito urbanistico: conflittualitĂ  nelle norme urbanistiche nazionali e locali in tema di sanitĂ  pubblica [Hygienic and sanitary aspects in urban planning: contradiction in national and local urban legislation regarding public health]

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    Nowadays, the majority of world population lives in urban areas and this portion is going to increase in the coming decades. The health impact of urban areas is well established and described in scientific literature. Italian health and hygiene legislation dealing with urban health is fragmented and not coordinated with the regulation about environment and city planning. The overlapping of legal competences between different authorities and the conflict of attribution between the Central State and Regional Governments deeply contributed to generate uncertainty. The authors here analyse the Italian regulatory framework and depict its lacks in terms of public health protection

    Laparoscopic One-Stage vs Endoscopic Plus Laparoscopic Management of Common Bile Duct Stones – A Prospective Randomized Study

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    Improvements in diagnostic and operative approach to CBD stones associated with cholelithiasis allow the surgeon to treat in a single stage the disease through a laparoscopic approach, The AA report the results of a prospective randomised study comparing this approach to a a double stage endoscopic plus laparoscopic cholecistectomy in 124 patients. techniques and procedures are referred and the results are statistically analysed. the outcome of the two procedures were recorded as success or failure according to the complete clearance of the CB

    Potential Therapeutic Effects of Vitamin E and C on Placental Oxidative Stress Induced by Nicotine: An In Vitro Evidence

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    There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. The adverse effect of prenatal smoking exposure on human fetal development and growth has been a major public health issue. Active or passive smoking during pregnancy can result in a wide variety of adverse outcomes, including intrauterine growth retardation (IUGR), prematurity, stillbirth, and the sudden infant death syndrome. Smoking in pregnancy has also been associated with an increased risk of attention deficit and learning problems in childhood. Some studies argued that as a principal component of tobacco smoke, nicotine alone is responsible for the majority of negative reproductive outcomes. Nicotine and its major metabolite cotinine can cross the placental barrier. The level of nicotine in fetal tissues was found to be equal to or greater than the plasma nicotine level in the mothers. The oxidative stress induce by nicotine has been increasingly postulated as a major contributor to endothelial dysfunction. A large body of research has investigated the potential role of antioxidant nutrients in the prevention of endothelial dysfunction in women. Therefore, the present study was undertaken to assess the potential benefit of antioxidant supplementation on markers of placental oxidative stress in an in vitro model of endothelial dysfunction induced by nicotine, since it was previously found that nicotine is able to trigger the placental secretion of stress molecules. In this regard, we evaluated the effects of vitamin C, vitamin E and N-acetylcysteine (NAC), alone or in combination, in placental villi culture after exposure to nicotine. The effect of antioxidant nutrients on trophoblast cells proliferation and vitality was also evaluated. The results obtained suggest that in a patho-physiological condition, such as endothelial dysfunction induced by nicotine, the deleterious effect of reactive oxygen species may be counteracted by an antioxidant therapy, and there is the need to investigate the optimum dosing and timing of antioxidants administration, since an inappropriate antioxidant treatment in pregnant women may have deleterious consequences, reducing placental cells proliferation until to cell death

    Polariton Nanophotonics using Phase Change Materials

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    Polaritons formed by the coupling of light and material excitations such as plasmons, phonons, or excitons enable light-matter interactions at the nanoscale beyond what is currently possible with conventional optics. Recently, significant interest has been attracted by polaritons in van der Waals materials, which could lead to applications in sensing, integrated photonic circuits and detectors. However, novel techniques are required to control the propagation of polaritons at the nanoscale and to implement the first practical devices. Here we report the experimental realization of polariton refractive and meta-optics in the mid-infrared by exploiting the properties of low-loss phonon polaritons in isotopically pure hexagonal boron nitride (hBN), which allow it to interact with the surrounding dielectric environment comprising the low-loss phase change material, Ge3_3Sb2_2Te6_6 (GST). We demonstrate waveguides which confine polaritons in a 1D geometry, and refractive optical elements such as lenses and prisms for phonon polaritons in hBN, which we characterize using scanning near field optical microscopy. Furthermore, we demonstrate metalenses, which allow for polariton wavefront engineering and sub-wavelength focusing. Our method, due to its sub-diffraction and planar nature, will enable the realization of programmable miniaturized integrated optoelectronic devices, and will lay the foundation for on-demand biosensors.Comment: 15 pages, 4 figures, typos corrected in v

    Qualitative versus automatic evaluation of CT perfusion parameters in acute posterior circulation ischaemic stroke

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    Purpose To compare the diagnostic accuracy (ACC) in the detection of acute posterior circulation strokes between qualitative evaluation of software-generated colour maps and automatic assessment of CT perfusion (CTP) parameters. Methods Were retrospectively collected 50 patients suspected of acute posterior circulation stroke who underwent to CTP (GE “Lightspeed”, 64 slices) within 24 h after symptom onset between January 2016 and December 2018. The Posterior circulation-Acute Stroke Prognosis Early CT Score (pc-ASPECTS) was used for quantifying the extent of ischaemic areas on non-contrast (NC)CT and colour-coded maps generated by CTP4 (GE) and RAPID (iSchemia View) software. Final pc-ASPECTS was calculated on follow-up NCCT and/or MRI (Philips Intera 3.0 T or Philips Achieva Ingenia 1.5 T). RAPID software also elaborated automatic quantitative mismatch maps. Results By qualitative evaluation of colour-coded maps, MTT-CTP4D and Tmax-RAPID showed the highest sensitivity (SE) (88.6% and 90.9%, respectively) and ACC (84% and 88%, respectively) compared with the other perfusion parameters (CBV, CBF). Baseline NCCT and CBF provided by RAPID quantitative perfusion mismatchmaps had the lowest SE (29.6%and 6.8%, respectively) and ACC (38% and 18%, respectively). CBF and Tmax assessment provided by quantitative RAPID perfusion mismatch maps showed significant lower SE and ACC than qualitative evaluation. No significant differences were found between the pc-ASPECTSs assessed on colour-coded MTT and Tmax maps neither between the scores assessed on colourcoded CBV-CTP4D and CBF-RAPID maps. Conclusion Qualitative analysis of colour-codedmaps resultedmore sensitive and accurate in the detection of ischaemic changes than automatic quantitative analysis
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