1,128 research outputs found

    Magnesium isotopes: a tool to understand self-enrichment in Globular Clusters

    Full text link
    A critical issue in the asymptotic giant branch (AGB) self-enrichment scenario for the formation of multiple populations in Globular Clusters (GCs) is the inability to reproduce the magnesium isotopic ratios, despite the model in principle can account for the depletion of magnesium. In this work we analyze how the uncertainties on the various p-capture cross sections affect the results related to the magnesium content of the ejecta of AGB stars. The observed distribution of the magnesium isotopes and of the overall Mg-Al trend in M13 and NGC 6752 are successfully reproduced when the proton-capture rate by 25Mg at the temperatures 100 MK, in particular the 25Mg(p, gamma)26Alm channel, is enhanced by a factor 3 with respect to the most recent experimental determinations. This assumption also allows to reproduce the full extent of the Mg spread and the Mg-Si anticorrelation observed in NGC 2419. The uncertainties in the rate of the 25Mg(p,gamma)26Alm reaction at the temperatures of interest here leave space for our assumption and we suggest that new experimental measurements are needed to settle this problem. We also discuss the competitive model based on the super massive star nucleosynthesis.Comment: accepted for publication on MNRA

    Coherent structures in an electron beam

    Full text link
    The formation and evolution of coherent structures in a low-energy electron beam produced in a Malmberg-Penning trap is investigated by means of CCD diagnostics. The electrons are emitted from a thermionic cathode and their energy is controlled by an acceleration grid. By varying the spatial distribution of the energy of emitted electrons, different space charge effects are observed, as, e. g., a sharp or a gradual transition to a space charge dominated regime. The variation of the coherent structures along the beam is studied by varying the electron density or/and the value of the confined magnetic field. The observed processes are interpreted using a tridimensional particle-in-cell code which solves the Vlasov-Poisson system in zeroth order drift approximation.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

    Alzheimer’s Disease: From Immune Homeostasis to Neuroinflammatory Condition

    Get PDF
    Alzheimer’s Disease is the most common cause in the world of progressive cognitive decline. Although many modifiable and non-modifiable risk factors have been proposed, in recent years, neuroinflammation has been hypothesized to be an important contributing factor of Alzheimer’s Disease pathogenesis. Neuroinflammation can occur through the combined action of the Central Nervous System resident immune cells and adaptive peripheral immune system. In the past years, immunotherapies for neurodegenerative diseases have focused wrongly on targeting protein aggregates Aβ plaques and NFT treatment. The role of both innate and adaptive immune cells has not been fully clarified, but several data suggest that immune system dysregulation plays a key role in neuroinflammation. Recent studies have focused especially on the role of the adaptive immune system and have shown that inflammatory markers are characterized by increased CD4+ Teff cells’ activities and reduced circulating CD4+ Treg cells. In this review, we discuss the key role of both innate and adaptive immune systems in the degeneration and regeneration mechanisms in the pathogenesis of Alzheimer’s Disease, with a focus on how the crosstalk between these two systems is able to sustain brain homeostasis or shift it to a neurodegenerative condition

    Pediatric palliative care

    Get PDF
    The WHO defines pediatric palliative care as the active total care of the child's body, mind and spirit, which also involves giving support to the family. Its purpose is to improve the quality of life of young patients and their families, and in the vast majority of cases the home is the best place to provide such care, but for cultural, affective, educational and organizational reasons, pediatric patients rarely benefit from such an approach. In daily practice, it is clear that pediatric patients experience all the clinical, psychological, ethical and spiritual problems that severe, irreversible disease and death entail. The international literature indicates a prevalence of incurable disease annually affecting 10/10,000 young people from 0 to 19 years old, with an annual mortality rate of 1/10,000 young people from birth to 17 years old. The needs of this category of patients, recorded in investigations conducted in various parts of the world, reveal much the same picture despite geographical, cultural, organizational and social differences, particularly as concerns their wish to be treated at home and the demand for better communications between the professionals involved in their care and a greater availability of support services. Different patient care models have been tested in Italy and abroad, two of institutional type (with children staying in hospitals for treating acute disease or in pediatric hospices) and two based at home (the so-called home-based hospitalization and integrated home-based care programs). Professional expertise, training, research and organization provide the essential foundations for coping with a situation that is all too often underestimated and neglected

    Prognostic role of minimal residual disease before and after hematopoietic stem cell transplantation in childhood acute lymphoblastic leukemia

    Get PDF
    More than 80% of children with acute lymphoblastic leukemia (ALL) can be cured through intensive and risk-oriented chemotherapy protocols. Allogeneic hematopoietic stem cell transplantation (HSCT) is considered bene\ufb01cial for approximately 10% of the patients who are at veryhigh risk at frontline therapy and for the majority of patients after relapse. Consequently, it is critically important to identify prognostic factors in this group of patients in order to tailor risk-adapted therapy. In this retrospective study, we aimed to assess the prognostic role of minimal residual disease (MRD) before HSCT and at di\ufb00erent time points after transplantation in children with ALL

    Exploiting magnetic properties of Fe doping in zirconia

    Full text link
    In this study we explore, both from theoretical and experimental side, the effect of Fe doping in ZrO2 (ZrO2:Fe). By means of first principles simulation we study the magnetization density and the magnetic interaction between Fe atoms. We also consider how this is affected by the presence of oxygen vacancies and compare our findings with models based on impurity band and carrier mediated magnetic interaction. Experimentally thin films (~ 20 nm) of ZrO2:Fe at high doping concentration are grown by atomic layer deposition. We provide experimental evidence that Fe is uniformly distributed in the ZrO2 by transmission electron microscopy and energy dispersive X-ray mapping, while X-ray diffraction evidences the presence of the fluorite crystal structure. Alternating gradient force magnetometer measurements show magnetic signal at room temperature, however with low magnetic moment per atom. Results from experimental measures and theoretical simulations are compared.Comment: 8 pages, 9 figures. JEMS 201

    Rare earth elements in human and animal health: State of art and research priorities

    Get PDF
    "Background: A number of applications have been developed using rare earth elements (REE), implying several human exposures and raising unsolved questions as to REE-associated health effects. Methods: A MedLine survey was retrieved from early reports (1980s) up to June 2015, focused on human and animal exposures to REE. Literature from animal models was selected focusing on REE-associated health effects. Results: Some REE occupational exposures, in jobs such as glass polishers, photoengravers and movie projectionists showed a few case reports on health effects affecting the respiratory system. No case-control or cohort studies of occupational REE exposures were retrieved. Environmental exposures have been biomonitored in populations residing in REE mining areas, showing REE accumulation. The case for a iatrogenic REE exposure was raised by the use of gadolinium-based contrast agents for nuclear magnetic resonance. Animal toxicity studies have shown REE toxicity, affecting a number of endpoints in liver, lungs and blood. On the other hand, the use of REE as feed additives in livestock is referred as a safe and promising device in zootechnical activities, possibly suggesting a hormetic effect both known for REE and for other xenobiotics. Thus, investigations on long-term exposures and observations are warranted. Conclusion: The state of art provides a limited definition of the health effects in occupationally or environmentally REE-exposed human populations. Research priorities should be addressed to case-control or cohort studies of REE-exposed humans and to life-long animal experiments. (C) 2015 Elsevier Inc. All rights reserved.

    DCF Data Call Coverage Report for the Mediterranean and Black Sea in 2014

    Get PDF
    DG Mare called the DCF Data from Member States in the Mediterranean and Black Sea on April 2014, defining the deadline of 9 June 2014 for data submissions from member states, under the Community Framework of Data Collection Regulation (DCR) (Council Regulation (EC) â„– 199/2008 of 25th February 2008). A second deadline specific for the Black Sea was established on 8 September 2014. The data call also defined a third deadline 12 January 2015 for the submission of trawl surveys data for Mediterranean MS. aruptii. The DCF data submitted by national correspondents are duly evaluated in the present coverage report by JRC DCF team as part of an Administrative Arrangement with DG MARE. The report provides a detailed review of the timeliness and completeness of data submissions by Member States.JRC.G.3-Maritime affair

    Contraception with estradiol valerate and dienogest: adherence to the method

    Get PDF
    Purpose: The aim of the study was to examine the discontinuation rate of hormonal contraception with estradiol valerate (E2V) and dienogest (DNG). Patients and methods: We collected data at the Family Planning Clinics of the Departments of Obstetrics and Gynecology of Pisa and Cagliari. We included in the analysis 354 consecutive women using oral contraceptive pills containing E2V and DNG. We analyzed the rate and the reason for discontinuation, classifying the reasons in 5 categories: 1) minor side effects, 2) adverse events, 3) other events not directly caused by the drug or conditions for which the pill could represent a risk factor, 4) no compliance with the method and 5) no further need. Results: Of the 354 women examined, 50.8% had discontinued E2V/DNG pill. Excluding women who stopped the pill because of no further need (10.5%), 27.4% discontinued because of minor side effects, 1.7% discontinued for adverse events, 9.9% because of other events not directly caused by the drug or conditions for which the pill could represent a risk factor and 1.4% because of difficulties with compliance. Irregular bleedings were the main reasons reported for discontinuation. The time to discontinuation for irregular bleedings was significantly (p<0.02) longer in adults than in adolescents and slightly but not significantly longer in women who received information about this possible effect. Conclusion: Unacceptable cycle control was the principal cause of discontinuation of pill with E2V and DNG. An appropriate information about this possible effect may improve adherence to this combined oral contraceptive
    • …
    corecore