219 research outputs found

    Lifetimes of C-60(2-) and C-70(2-) dianions in a storage ring

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    C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb barrier, mainly from thermally populated triplet states about 120 meV above a singlet ground state. At times longer than about 100 ms, the absorption of blackbody radiation plays an important role for the decay of initially cold ions. The tunneling rates obtained from the modeling, combined with WKB estimates of the barrier penetration, give a ground-state energy 200 +/- 30 meV above the energy of the monoanion plus a free electron and a ground-state lifetime of the order of 20 s. (c) 2006 American Institute of Physics

    Screening for elderly patients admitted to the emergency department requiring specialized geriatric care

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    BACKGROUND: There is a need for a brief geriatric assessment (BGA) tool to screen elderly patients admitted to the Emergency Department (ED) for their risk of a long hospital stay. OBJECTIVE: To examine whether a BGA administered to elderly patients admitted to the ED may predict the risk of a long hospital stay in the geriatric acute care unit. METHODS: This study had a prospective cohort study design, enrolling 424 elderly patients (mean age 84.0 +/- 6.5 years, 31.6% male) who were evaluated in the ED using a BGA composed of the following items: age, gender, number of medications taken daily, history of falls during the past 6 months, Mini-Mental State Examination (MMSE) score, and non-use of home-help services (i.e., living alone without using any formal or informal home services or social help). The length of stay (LOS) was calculated in days. Patients were separated into three groups based on LOS: low (<8 days), intermediate (8-13 days), and high (>13 days). RESULTS: The prevalence of male gender was higher among patients with the longest LOS compared to those with intermediate LOS (p = 0.002). There were more patients with a history of falls in the high LOS group compared to the intermediate LOS group (p = 0.001) and the low LOS group (p < 0.001). The classification tree showed that male patients with an MMSE score <20 who fell with age under 85 years formed the end node with the greatest relative risk (RR) of a long hospital stay (RR = 14.3 with p < 0.001). CONCLUSIONS: The combination of a history of falls, male gender, cognitive impairment, and age under 85 years identified elderly ED patients at high risk of a long hospital stay

    Association between vitamin D deficiency and long hospital stay in geriatric acute care unit: results from a pilot cohort study

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    Finding a biomarker of long length-of-stay (LOS) would provide a simple solution to target frail older inpatients at such risk. The aim of this study was to determine whether serum 25-hydroxyvitamin D (25OHD) deficiency, defined as serum concentration <25 nmol/L, was associated with long LOS among inpatients admitted to a geriatric acute care unit. Three hundred and six older inpatients (mean age 84.6 +/- 6.4 years, 61.8 % women) were consecutively included in this longitudinal prospective cohort study. Patients were separated into two groups according to LOS tertiles: highest tertile (>= 14 days; n = 120) versus the other two tertiles combined (<14 days; n = 186). Serum 25OHD deficiency (58.3 vs. 38.7 %, P = 0.001) and the prevalence of male gender (58.3 vs. 28.5 %, P < 0.001) were higher among inpatients with the highest LOS compared with those with lower LOS. Serum 25OHD deficiency [odds ratio (OR) = 2.22, P = 0.001 for unadjusted model; OR = 1.87, P = 0.012 for fully adjusted model) and male gender (OR = 2.87, P < 0.001 for unadjusted model; OR = 2.64, P = 0.001 for full model) were associated with a high LOS. Vitamin D deficiency and male gender were risk factors for a long LOS in this pilot study. Using these risk factors to identify inpatients at risk of long LOS may be helpful in adapting early care plans, and thus improving inpatients\u27 health and shortening LOS

    MONOBOB II : Latest results of monocharged ions source for SPIRAL2 project

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    Original publication available at http://www.jacow.orgInternational audienceAmong the sources which can be installed in the radioactive ion production module of SPIRAL II, a singly-charged ECRIS has been chosen to produce ions from gaseous elements. Its characterization is under way on a test bench at GANIL. Extraction, transport and response time results are presented

    Nuclear structure and reaction studies at SPIRAL

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    The SPIRAL facility at GANIL, operational since 2001, is described briefly. The diverse physics program using the re-accelerated (1.2 to 25 MeV/u) beams ranging from He to Kr and the instrumentation specially developed for their exploitation are presented. Results of these studies, using both direct and compound processes, addressing various questions related to the existence of exotic states of nuclear matter, evolution of new "magic numbers", tunnelling of exotic nuclei, neutron correlations, exotic pathways in astrophysical sites and characterization of the continuum are discussed. The future prospects for the facility and the path towards SPIRAL2, a next generation ISOL facility, are also briefly presented.Comment: 48 pages, 27 figures. Accepted for publication in Journal of Physics

    Transcriptional landscape of bone marrow-derived very small embryonic-like stem cells during hypoxia

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    <p>Abstract</p> <p>Background</p> <p>Hypoxia is a ubiquitous feature of many lung diseases and elicits cell-specific responses. While the effects of hypoxia on stem cells have been examined under <it>in vitro </it>conditions, the consequences of <it>in vivo </it>oxygen deprivation have not been studied.</p> <p>Methods</p> <p>We investigated the effects of <it>in vivo </it>hypoxia on a recently characterized population of pluripotent stem cells known as very small embryonic-like stem cells (VSELs) by whole-genome expression profiling and measuring peripheral blood stem cell chemokine levels.</p> <p>Results</p> <p>We found that exposure to hypoxia in mice mobilized VSELs from the bone marrow to peripheral blood, and induced a distinct genome-wide transcriptional signature. Applying a computationally-intensive methodology, we identified a hypoxia-induced gene interaction network that was functionally enriched in a diverse array of programs including organ-specific development, stress response, and wound repair. Topographic analysis of the network highlighted a number of densely connected hubs that may represent key controllers of stem cell response during hypoxia and, therefore, serve as putative targets for altering the pathophysiologic consequences of hypoxic burden.</p> <p>Conclusions</p> <p>A brief exposure to hypoxia recruits pluripotent stem cells to the peripheral circulation and actives diverse transcriptional programs that are orchestrated by a selective number of key genes.</p
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