15 research outputs found

    Ion-stimulated gas desorption yields and their dependence on the surface preparation of stainless steel

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    Ion-induced gas desorption yields were investigated for 4.2 MeV/u lead ions incident on 316 LN stainless steel surfaces. Focussed on a possible application for the Low Energy Ion Ring (LEIR) vacuum system, the influence of surface treatments like chemical etching, electropolishing and gold-coating on the desorption yields was studied with accelerator-type vacuum chambers. The surface composition of similar prepared samples was investigated with X-ray Photoemission Spectroscopy (XPS). Desorption yields for H2, CH4, CO, Ar and CO2, which are of fundamental interest for LEIR and future accelerator applications, are reported as a function of impact angle, ion dose and charge state (+27, +53) of the lead ion beam

    Experimental evaluation of niobium film pinholes [for LEP cavities]

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    To assess the quality of vacuum-deposited films, well-defined areas of free-hanging thin film may be obtained by chemically dissolving the substrate on a fraction of its surface. A global evaluation of the thin film pinholes is then possible by measuring the gas conductance across the film. To do so, copper discs clamped between Con-Flat flanges have been used to separate a chamber filled with helium gas from another chamber where the helium throughput was measured. This method has been used to compare films produced under dust-free and dusty conditions, of various surface roughnesses and at different deposition incidence angles

    Ion-stimulated gas desorption yields of coated (Au, Ag, Pd) stainless steel vacuum chambers irradiated with 4.2 MeV/u lead ions

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    The ion-induced desorption experiment, installed in the CERN Heavy Ion Accelerator (LINAC 3), has been used to measure molecular desorption yields for 4.2 MeV/u lead ions impacting on different accelerator-type vacuum chambers. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, and palladium-coated 316LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analysed for chemical composition by X-ray Photoemission Spectroscopy (XPS). The large effective desorption yield of 2 x 10**4 molecules/ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble metal coating by up to 2 orders of magnitude. In addition, the effectiveness of beam scrubbing with heavy ions and the consequence of a subsequent venting on the desorption yields of a beam-scrubbed vacuum chamber are described. Practical consequences for the vacuum system of the future Low Energy Ion Ring (LEIR) are discussed

    Ion-stimulated gas desorption yields of electropolished, chemically etched, and coated (Au, Ag, Pd, TiZrV) stainless steel vacuum chambers and St707 getter strips irradiated with 4.2  MeV/u lead ions

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    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to measure molecular desorption yields for 4.2  MeV/u lead ions impacting under grazing incidence on different accelerator-type vacuum chambers. Desorption yields for H_{2}, CH_{4}, CO, and CO_{2}, which are of fundamental interest for future accelerator applications, are reported for different stainless steel surface treatments. In order to study the effect of the surface oxide layer on the gas desorption, gold-, silver-, palladium-, and getter-coated 316 LN stainless steel chambers and similarly prepared samples were tested for desorption at LINAC 3 and analyzed for chemical composition by x-ray photoemission spectroscopy. The large effective desorption yield of 2×10^{4}   molecules /Pb^{53+} ion, previously measured for uncoated, vacuum fired stainless steel, was reduced after noble-metal coating by up to 2 orders of magnitude. In addition, pressure rise measurements, the effectiveness of beam scrubbing with lead ions, and the consequence of a subsequent venting on the desorption yields of a beam-scrubbed vacuum chamber are described. Practical consequences for the vacuum system of the future Low Energy Ion Ring are discussed

    Objective and self-reported cognitive dysfunction in breast cancer women treated with chemotherapy: a prospective study

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    The objective of this study is to investigate if changes in cognitive functions can be recognised in patients undergoing chemotherapy for breast cancer. Forty women with breast cancer and without depression underwent cognitive evaluation before and after 6 months of chemotherapy; emotional evaluation was performed before and after 1, 3 and 6 months of chemotherapy. Self-reported cognitive deficit evaluation was included. Global cognitive functioning before starting chemotherapy was good. After 6 months of treatment there was a significant decline in some cognitive functions, particularly involving the attention subdomain. Objective cognitive deficit resulted independent from the emotional status. On the contrary, self-perceived mental dysfunction was unrelated to the objective cognitive decline, but it was associated with depression and anxiety. Breast cancer chemotherapy can induce domain-specific cognitive dysfunction. Patients' self-perception of mental decline is unrelated to objective cognitive deficit. Breast cancer patients negatively judge their cognitive performances if they have a negative emotional functioning.status: publishe

    Vitamin D deficiency is associated with impaired reperfusion in STEMI patients undergoing primary percutaneous coronary intervention

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    Background and aims: Vitamin D displays a broad spectrum of cardioprotective effects, preventing oxidative stress, inflammation and thrombosis and improving endothelial function. Previous studies have associated vitamin D deficiency with more extended and severe coronary artery disease (CAD) and worse outcome, and especially among patients with ST-segment elevation myocardial infarction (STEMI). However, few data have been reported on the association of vitamin D levels with the angiographic findings and epicardial reperfusion in STEMI patients undergoing primary percutaneous coronary intervention (pPCI), that was therefore the aim of the present study. Methods and results: A consecutive cohort of patients admitted for STEMI and treated with pPCI were included. The levels of 25(OH)D were assessed at admission by chemiluminescence immunoassay kit LIAISON\uae Vitamin D assay (Diasorin Inc). Hypovitaminosis D was defined for 25(OH)D < 10 ng/ml. We included in our study 450 patients, divided according to tertiles values of 25(OH)D. Lower vitamin D was associated to a higher use of diuretics (p = 0.02), higher levels of white blood cells and glycemia (p < 0.001), lower prevalence of lesions on bifurcations (p = 0.03) and smaller diameter of the target coronary vessel (p = 0.03). Procedural characteristics and pre-procedural TIMI flow were not different according to vitamin D levels, but for a higher rate of impaired epicardial reperfusion (12.8% vs 8.1% vs 5.3%, p = 0.03, adjusted OR[95%CI] = 2.6[1.05\u20136.6], p = 0.04 for I vs III tertile), requiring higher use of adenosine (p = 0.006) and glycoprotein IIbIIIa inhibitors (p = 0.01). Conclusion: The present study shows that among patients with STEMI undergoing pPCI, lower levels of vitamin D are independently associated with impaired reperfusion, Future dedicated studies will shed light on the prognostic implications of hypovitaminosis D in these patients and the potential therapeutic perspectives
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