645 research outputs found

    High purity nanoparticles exceed stoichiometry limits in rebox chemistry: the nano way to cleaner water

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    A potentially cheaper and more effective way of cleaning wastewater has been discovered by scientists at Nazarbayev University and the University of Brighton researching nanotechnology [1]. It is well established that when particles are reduced to the nanoscale unexpected effects occur. Silver, for example, interacts with mercury ions in a fixed ratio of atoms (stoichiometry), typically 2:1, which presents a limit that has never been exceeded. In this project we used an alternative chemical procedure based on modified quartz sand to immobilise silver nanoparticles (NPs) with control over their size. We found that when the size of the silver NPs decreased below 35 nm the amount of mercury ions reacting with silver increased beyond the long-held limit and rose to a maximum of 1:1.2 for 10 nm sized silver

    High purity nanoparticles exceed stoichiometry limits in rebox chemistry: the nano way to cleaner water

    Get PDF
    A potentially cheaper and more effective way of cleaning wastewater has been discovered by scientists at Nazarbayev University and the University of Brighton researching nanotechnology [1]. It is well established that when particles are reduced to the nanoscale unexpected effects occur. Silver, for example, interacts with mercury ions in a fixed ratio of atoms (stoichiometry), typically 2:1, which presents a limit that has never been exceeded. In this project we used an alternative chemical procedure based on modified quartz sand to immobilise silver nanoparticles (NPs) with control over their size. We found that when the size of the silver NPs decreased below 35 nm the amount of mercury ions reacting with silver increased beyond the long-held limit and rose to a maximum of 1:1.2 for 10 nm sized silver

    ChPT tests at the NA48 and NA62 experiments at CERN

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    The NA48/2 Collaboration at CERN has accumulated unprecedented statistics of rare kaon decays in the Ke4 modes: Ke4(+-) (K±→π+π−e±ΜK^\pm \to \pi^+ \pi^- e^\pm \nu) and Ke4(00) (K±→π0π0e±ΜK^\pm \to \pi^0 \pi^0 e^\pm \nu) with nearly one percent background contamination. The detailed study of form factors and branching rates, based on these data, has been completed recently. The results brings new inputs to low energy strong interactions description and tests of Chiral Perturbation Theory (ChPT) and lattice QCD calculations. In particular, new data support the ChPT prediction for a cusp in the π0π0\pi^0\pi^0 invariant mass spectrum at the two charged pions threshold for Ke4(00) decay. New final results from an analysis of about 400 KÂ±â†’Ï€Â±ÎłÎłK^\pm \to \pi^\pm \gamma \gamma rare decay candidates collected by the NA48/2 and NA62 experiments at CERN during low intensity runs with minimum bias trigger configurations are presented. The results include a model-independent decay rate measurement and fits to ChPT description.Comment: XIIth International Conference on Heavy Quarks and Leptons 2014, Mainz, German

    Recent NA48/2 and NA62 results

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    The NA48/2 Collaboration at CERN has accumulated and analysed unprecedented statistics of rare kaon decays in the Ke4K_{e4} modes: Ke4(+−)K_{e4}(+-) (K±→π+π−e±ΜK^\pm \to \pi^+ \pi^- e^\pm \nu) and Ke4(00)K_{e4}(00) (K±→π0π0e±ΜK^\pm \to \pi^0 \pi^0 e^\pm \nu) with nearly one percent background contamination. It leads to the improved measurement of branching fractions and detailed form factor studies. New final results from the analysis of 381 KÂ±â†’Ï€Â±ÎłÎłK^\pm \to \pi^\pm \gamma \gamma rare decay candidates collected by the NA48/2 and NA62 experiments at CERN are presented. The results include a decay rate measurement and fits to Chiral Perturbation Theory (ChPT) description.Comment: Prepared for the Proceedings of "Moriond QCD and High Energy Interactions. March 22-29 2014." conferenc

    Measurement of the branching ratio of the decay Ξ0→Σ+Ό−ΜˉΌ\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}

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    From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 Ξ0→Σ+Ό−ΜˉΌ\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu} candidates with a background contamination of 30.8±4.230.8 \pm 4.2 events. From this sample, the BR(Ξ0→Σ+Ό−ΜˉΌ\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}) is measured to be (2.17±0.32stat±0.17syst)×10−6(2.17 \pm 0.32_{\mathrm{stat}}\pm 0.17_{\mathrm{syst}})\times10^{-6}

    First observation of the KS->pi0 gamma gamma decay

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    Using the NA48 detector at the CERN SPS, 31 KS->pi0 gamma gamma candidates with an estimated background of 13.7 +- 3.2 events have been observed. This first observation leads to a branching ratio of BR(KS->pi0 gamma gamma) = (4.9 +- 1.6(stat) +- 0.9(syst)) x 10^-8 in agreement with Chiral Perturbation theory predictions.Comment: 10 pages, 4 figures submitted to Phys. Lett.

    Observation of the rare decay K_S -> pi^0mu^+mu^-

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    A search for the decay K_S -> pi^0mu^+mu^- has been made by the NA48/1 Collaboration at the CERN SPS accelerator. The data were collected during 2002 with a high-intensity K_S beam. Six events were found with a background expectation of 0.22^+0.18_-0.11 event. Using a vector matrix element and unit form factor, the measured branching ratio is B(K_S -> pi^0mu^+mu^-)=[2.9^+1.5_-1.2(stat)+/-0.2(syst)]x10^{-9}.Comment: 19 pages, 8 figures, 4 tables. To be published in Physics Letters

    Subcutaneous dissociative conscious sedation (sDCS) an alternative method for airway regional blocks: a new approach

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    <p>Abstract</p> <p>Background</p> <p>Predicted difficult airway is a definite indication for awake intubation and spontaneous ventilation. Airway regional blocks which are commonly used to facilitate awake intubation are sometimes impossible or forbidden. On the other hand deep sedation could be life threatening in the case of compromised airway.</p> <p>The aim of this study is evaluating "Subcutaneous Dissociative Conscious Sedation" (sDCS) as an alternative method to airway regional blocks for awake intubation.</p> <p>Methods</p> <p>In this prospective, non-randomized study, 30 patients with predicted difficult airway (laryngeal tumors), who were scheduled for direct laryngoscopic biopsy (DLB), underwent "Subcutaneous Dissociative Conscious Sedation" (sDCS) exerted by intravenous fentanyl 3-4ug/kg and subcutaneous ketamine 0.6-0.7 mg/kg. The tongue and pharynx were anesthetized with lidocaine spray (4%<b>)</b>. 10 minutes after a subcutaneous injection of ketamine direct laryngoscopy was performed. Extra doses of fentanyl 50-100 ug were administered if the patient wasn't cooperative enough for laryngoscopy.</p> <p>Patients were evaluated for hemodynamic stability (heart rate and blood pressure), oxygen saturation (Spo<sub>2</sub>), patient cooperation (obedient to open the mouth for laryngoscopy and the number of tries for laryngoscopy), patient comfort (remaining moveless), hallucination, nystagmus and salivation (need for aspiration before laryngoscopy).</p> <p>Results</p> <p>Direct laryngoscopy was performed successfully in all patients. One patient needed extra fentanyl and then laryngoscopy was performed successfully on the second try. All patients were cooperative enough during laryngoscopy. Hemodynamic changes more than 20% occurred in just one patient. Oxygen desaturation (spo<sub>2</sub>< 90%) didn't occur in any patient.</p> <p>Conclusions</p> <p>Subcutaneous Dissociative Conscious Sedation (sDCS) as a new approach to airway is an acceptable and safe method for awake intubation and it can be suggested as a noninvasive substitute of low complication rate for regional airway blocks.</p> <p>Registration ID in IRCT</p> <p>IRCT201012075333N1</p

    First Observation and Measurement of the Decay K+- -> pi+- e+ e- gamma

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    Using the full data set of the NA48/2 experiment, the decay K+- -> pi+- e+ e- gamma is observed for the first time, selecting 120 candidates with 7.3 +- 1.7 estimated background events. With K+- -> pi+- pi0D as normalisation channel, the branching ratio is determined in a model-independent way to be Br(K+- -> pi+- e+ e- gamma, m_eegamma > 260 MeV/c^2) = (1.19 +- 0.12_stat +- 0.04_syst) x 10^-8. This measured value and the spectrum of the e+ e- gamma invariant mass allow a comparison with predictions of Chiral Perturbation Theory.Comment: 13 pages, 3 figures. Accepted for publication in Phys.Lett.

    Search for CP violation in K0 -> 3 pi0 decays

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    Using data taken during the year 2000 with the NA48 detector at the CERN SPS, a search for the CP violating decay K_S -> 3 pi0 has been performed. From a fit to the lifetime distribution of about 4.9 million reconstructed K0/K0bar -> 3 pi0 decays, the CP violating amplitude eta_000 = A(K_S -> 3 pi0)/A(K_L -> 3 pi0) has been found to be Re(eta_000) = -0.002 +- 0.011 +- 0.015 and Im(eta_000) = -0.003 +- 0.013 +- 0.017. This corresponds to an upper limit on the branching fraction of Br(K_S -> 3 pi0) < 7.4 x 10^-7 at 90% confidence level. The result is used to improve knowledge of Re(epsilon) and the CPT violating quantity Im(delta) via the Bell-Steinberger relation.Comment: 18 pages, 7 figures, submitted to Phys. Lett.
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