696 research outputs found

    Double Ionisation in R-Matrix Theory Using a 2-electron Outer Region

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    We have developed a two-electron outer region for use within R-matrix theory to describe double ionisation processes. The capability of this method is demonstrated for single-photon double ionisation of He in the photon energy region between 80 eV to 180 eV. The cross sections are in agreement with established data. The extended RMT method also provides information on higher-order processes, as demonstrated by the identification of signatures for sequential double ionisation processes involving an intermediate He+^{+} state with n=2n=2.Comment: 5 pages, 4 figure

    Java binary computability is almost correct version 2∝

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    The Java language description is unusual in that it defines the effect of interleaving separate compilation and source code modifications. In Java, certain source code modifications, such as adding a method to a class, are defined as binary compatible. The Java language description does not require the re-compilation of programs importing classes or interfaces which were modified in binary compatible ways, and it claims that successful linking and execution of the altered program is guaranteed. In this paper we show that Java binary compatibility does not actually guarantee successful linking and execution. We then suggest a framework in which we formalize the requirement of safe linking and execution without re-compilation and we propose a more modest definition of binary compatibility. We prove for a substantial subset of Java, that our definition guarantees safe linking and execution

    The Jahn-Teller active fluoroperovskites ACrF3A\mathrm{CrF_3} A=Na+,K+A=\mathrm{Na^+},\mathrm{K^+}: thermo- and magneto optical correlations as function of the AA-site

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    Chromium (II) fluoroperovskites ACrF3(A=Na+,K+)A\mathrm{CrF_3}(A\mathrm{=Na^+,K^+}) are strongly correlated Jahn-Teller active materials at low temperatures. In this paper, we examine the role that the AA-site ion plays in this family of fluoroperovskites using both experimental methods (XRD, optical absorption spectroscopy and magnetic fields) and DFT simulations. Temperature-dependent optical absorption experiments show that the spin-allowed transitions E2E_2 and E3E_3 only merge completely for AA= Na at 2 K. Field-dependent optical absorption measurements at 2 K show that the oscillating strength of the spin-allowed transitions in NaCrF3\mathrm{NaCrF_3} increases with increasing applied field. Direct magneto-structural correlations which suppress the spin-flip transitions are observed for KCrF3{\rm KCrF_3} below its Ne\'el temperature. In NaCrF3{\rm NaCrF_3} the spin-flip transitions vanish abruptly below 9 K revealing magneto-optical correlations not linked to crystal structure changes. This suggests that as the long range ordering is reduced local JT effects in the individual CrF64{\rm CrF_6^{4-}} octahedra take control of the observed behavior. Our results show clear deviation from the pattern found for the isoelectronic AxMnF3+xA_x{\rm MnF}_{3+x} system. The size of the AA-site cation is shown to be central in dictating the physical properties and phase transitions in ACrF3A{\rm CrF}_3, opening up the possibility of varying the composition to create novel states of matter with tuneable properties

    Systematic Review of miRNA as Biomarkers in Alzheimer's Disease.

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    Currently there are 850,000 people with Alzheimer's disease in the UK, with an estimated rise to 1.1 million by 2025. Alzheimer's disease is characterised by the accumulation of amyloid-beta plaques and hyperphosphorylated tau in the brain causing a progressive decline in cognitive impairment. Small non-coding microRNA (miRNA) sequences have been found to be deregulated in the peripheral blood of Alzheimer patients. A systematic review was conducted to extract all miRNA found to be significantly deregulated in the peripheral blood. These deregulated miRNAs were cross-referenced against the miRNAs deregulated in the brain at Braak Stage III. This resulted in a panel of 10 miRNAs (hsa-mir-107, hsa-mir-26b, hsa-mir-30e, hsa-mir-34a, hsa-mir-485, hsa-mir200c, hsa-mir-210, hsa-mir-146a, hsa-mir-34c, and hsa-mir-125b) hypothesised to be deregulated early in Alzheimer's disease, nearly 20 years before the onset of clinical symptoms. After network analysis of the 10 miRNAs, they were found to be associated with the immune system, cell cycle, gene expression, cellular response to stress, neuron growth factor signalling, wnt signalling, cellular senescence, and Rho GTPases

    Glycoprotein IIb/IIIa Inhibitors Use and Outcome after Percutaneous Coronary Intervention for Non-ST Elevation Myocardial Infarction

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    Aims. We investigate the effect of glycoprotein IIb/IIIa (GP IIb/IIIa) inhibitors on long-term outcomes following percutaneous coronary intervention (PCI) after non-ST elevation myocardial infarction (NSTEMI). Meta-analyses indicate that these agents are associated with improved short-term outcomes. However, many trials were undertaken before the routine use of P2Y12 inhibitors. Recent studies yield conflicting results and registry data have suggested that GP IIb/IIIa inhibitors may cause more bleeding than what trials indicate. Methods and Results. This retrospective observational study involves 3047 patients receiving dual-antiplatelet therapy who underwent PCI for NSTEMI. Primary outcome was all-cause mortality. Major adverse cardiac events (MACE) were a secondary outcome. Mean follow-up was 4.6 years. Patients treated with GP IIb/IIIa inhibitors were younger with fewer comorbidities. Although the unadjusted Kaplan-Meier analysis suggested that GP IIb/IIIa inhibitor use was associated with improved outcomes, multivariate analysis (including propensity scoring) showed no benefit for either survival (P=0.136) or MACE (P=0.614). GP IIb/IIIa inhibitor use was associated with an increased risk of major bleeding (P=0.021). Conclusion. Although GP IIb/IIIa inhibitor use appeared to improve outcomes after PCI for NSTEMI, patients who received GP IIb/IIIa inhibitors tended to be at lower risk. After multivariate adjustment we observed no improvement in MACE or survival and an increased risk of major bleeding

    4,7,13,18-Tetra­oxa-1,10-diazo­nia­bicyclo­[8.5.5]icosane hexa­fluorido­silicate

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    The asymmetric unit of the title molecular salt, C14H30N2O4 2+·SiF6 2−, contains half of both the anion and the cation, both ions being completed by a crystallographic twofold axis passing through the Si atom. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter­molecular inter­actions and form only intra­molecular contacts. There are short inter­molecular C—H⋯F inter­actions in the structure, but no conventional inter­molecular hydrogen bonds

    4,7,13,18-Tetra­oxa-1,10-diazo­nia­bicyclo­[8.5.5]icosane bis­(hexa­fluorido­phosphate)

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    The asymmetric unit of the title structure, C14H30N2O4 2+·2PF6 −, contains the anion and half of the cation, the latter being completed by a crystallographic twofold axis. The cation has a cage structure with the ammonium H atoms pointing into the cage. These H atoms are shielded from inter­molecular inter­actions and form only intra­molecular contacts. There are short inter­molecular C—H⋯F inter­actions in the structure, but no conventional inter­molecular hydrogen bonds

    Determination of the nature of the Cu coordination complexes formed in the presence of NO and NH3 within SSZ-13

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    Ammonia-selective catalytic reduction (NH3-SCR) using Cu zeolites is a well-established strategy for the abatement of NOx gases. Recent studies have demonstrated that Cu is particularly active when exchanged into the SSZ-13 zeolite, and its location in either the 6r or 8r renders it an excellent model system for fundamental studies. In this work, we examine the interaction of NH3-SCR relevant gases (NO and NH3) with the Cu2+ centers within the SSZ-13 structure, coupling powder diffraction (PD), X-ray absorption spectroscopy (XAFS), and density functional theory (DFT). This combined approach revealed that, upon calcination, cooling and gas exposure Cu ions tend to locate in the 8r window. After NO introduction, Cu-ions are seen to coordinate to two framework oxygens and one NO molecule, resulting in a bent Cu-nitrosyl complex with a Cu-N-O bond angle of similar to 150 degrees. Whilst Cu seems to be partially reduced/changed in coordination state, NO is partially oxidized. On exposure to NH3 while the PD data suggest the Cu2+ ion occupies a similar position, simulation and XAFS pointed toward the formation of a Jahn-Teller distorted hexaamine complex [Cu(NH3)(6)](2+) in the center of the cha cage. These results have important implications in terms of uptake and storage of these reactive gases and potentially for the mechanisms involved in the NH3-SCR process

    (E)-1-(2-Iodo­phen­yl)-2-phenyl­diazene

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    The mol­ecule of the title compound, C12H9IN2, is approximately planar [maximum deviation = 0.020 (5) Å] with a trans arrangement of the groups around the N=N double bond. This double bond is rotated away from the iodine substiuent
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