370 research outputs found

    Do neutrons publish? A neutron publication survey 2005-2015

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    Publication in scientific journals is the main product of scientific research. The amount of papers published, their placement in high impact journals, and their citations are used as a measure of the productivity of individual scientists, institutes or fields of science. To give a profound basis on the publication record and the quality of the publication efforts in neutron scattering, a survey has been done following the approach to use bibliographic databases. Questions to be addressed by this survey are: Is the productivity of research with neutrons changing over the years? Which is the geographic distribution in this field of research? Which ones are leading facilities? Is the quality of publications changing? The main results found are presented

    Surfactant mixtures at the oil–water interface

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    NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Colloid and Interface Science. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in JOURNAL OF COLLOID AND INTERFACE SCIENCE, VOL 398, (2013) DOI 10.1016/j.jcis.2013.01.06

    Cardiolipin, α-d-glucopyranosyl, and l-lysylcardiolipin from Gram-positive bacteria: FAB MS, monofilm and X-ray powder diffraction studies

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    AbstractCardiolipin preparations from Streptococcus B, Listeria welshimeri, Staphylococcus aureus, and a glucosyl and lysyl derivative of cardiolipin were analysed for fatty acid composition and fatty acid combinations. Three different fatty acid patterns are described and up to 17 molecular species were identified in Streptococcus B lipids by high resolution FAB MS. The physicochemical properties of these lipids were characterised in the sodium salt form by monofilm experiments and X-ray powder diffraction. All lipids formed stable monofilms. The minimal space requirement of unsubstituted cardiolipin was dictated by the fatty acid pattern. Substitution with l-lysine led to a decrease of the molecular area, substitution with d-glucopyranosyl to an increase. On self assembly at 100% relative humidity, all preparations adopted lamellar structures. They showed a high degree of order, in spite of the heterogeneous fatty acid compositions and numerous fatty acid combinations. The repeat distances in lamellar fluid phase varied between 4.99 and 5.52 nm, the bilayer thickness between 3.70 and 4.46 nm. Surprising were the low values of sorbed water per molecule of the glucosyl and lysyl derivatives which were 58 and 60%, compared with those of the respective cardiolipin. When Na+ was replaced as counterion by Ba2+, the bilayer structure was retained, but the lipids were in the lamellar gel phase and the fatty acids were tilted between 32 and 53° away from the bilayer normal. Wide angle X-ray diffraction studies and electron density profiles are also reported. Particular properties of glucosyl cardiolipin are discussed

    Reverse hydrotropy by complex formation

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    Magnetic Proximity Effect in Perovskite Superconductor/Ferromagnet Multilayers

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    YBa2Cu3O7/La2/3Ca1/3MnO3\mathrm{YBa_2Cu_3O_7/La_{2/3}Ca_{1/3}MnO_3} superconducting/ferromagnetic (SC/FM) multilayers have been studied by neutron reflectometry. Evidence for a characteristic difference between the structural and magnetic depth profiles is obtained from the occurrence of a structurally forbidden Bragg peak in the FM state. The comparison with simulated reflectivity curves allows us to identify two possible magnetization profiles: a sizable magnetic moment within the SC layer antiparallel to the one in the FM layer (inverse proximity effect), or a ``dead'' region in the FM layer with zero net magnetic moment. The former scenario is supported by an anomalous SC-induced enhancement of the off-specular reflection, which testifies to a strong mutual interaction of SC and FM order parameters.Comment: 4 pages, 2 figures, submitted to PR

    Impact of Right Atrial Physiology on Heart Failure and Adverse Events after Myocardial Infarction

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    Background: Right ventricular (RV) function is a known predictor of adverse events in heart failure and following acute myocardial infarction (AMI). While right atrial (RA) involvement is well characterized in pulmonary arterial hypertension, its relative contributions to adverse events following AMI especially in patients with heart failure and congestion need further evaluation. Methods: In this cardiovascular magnetic resonance (CMR)-substudy of AIDA STEMI and TATORT NSTEMI, 1235 AMI patients underwent CMR after primary percutaneous coronary intervention (PCI) in 15 centers across Germany (n = 795 with ST-elevation myocardial infarction and 440 with non-ST-elevation MI). Right atrial (RA) performance was evaluated using CMR myocardial feature tracking (CMR-FT) for the assessment of RA reservoir (total strain εs), conduit (passive strain εe), booster pump function (active strain εa), and associated strain rates (SR) in a blinded core-laboratory. The primary endpoint was the occurrence of major adverse cardiac events (MACE) 12 months post AMI. Results: RA reservoir (εs p = 0.061, SRs p = 0.049) and conduit functions (εe p = 0.006, SRe p = 0.030) were impaired in patients with MACE as opposed to RA booster pump (εa p = 0.579, SRa p = 0.118) and RA volume index (p = 0.866). RA conduit function was associated with the clinical onset of heart failure and MACE independently of RV systolic function and atrial fibrillation (AF) (multivariable analysis hazard ratio 0.95, 95% confidence interval 0.92 to 0.99, p = 0.009), while RV systolic function and AF were not independent prognosticators. Furthermore, RA conduit strain identified low- and high-risk groups within patients with reduced RV systolic function (p = 0.019 on log rank testing). Conclusions: RA impairment is a distinct feature and independent risk factor in patients following AMI and can be easily assessed using CMR-FT-derived quantification of RA strain

    Fe and N self-diffusion in amorphous FeN: A SIMS and neutron reflectivity study

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    Simultaneous measurement of self-diffusion of iron and nitrogen in amorphous iron nitride (Fe86N14) using secondary ion mass spectroscopy (SIMS) technique has been done. In addition neutron reflectivity (NR) technique was employed to study the Fe diffusion in the same compound. The broadening of a tracer layer of 57Fe8615N14 sandwiched between Fe86N14 layers was observed after isothermal vacuum annealing of the films at different temperatures in SIMS measurements. And a decay of the Bragg peak intensity after isothermal annealing was observed in [Fe86N14/57Fe86N14]10 multilayers in NR. Strong structural relaxation of diffusion coefficient was observed below the crystallization temperature of the amorphous phase in both measurements. It was observed from the SIMS measurements that Fe diffusion was about 2 orders of magnitude smaller compared to nitrogen at a given temperature. The NR measurements reveal that the mechanism of Fe self-diffusion is very similar to that in metal-metal type metallic glasses. The structural relaxation time for Fe and N diffusion was found comparable indicating that the obtained relaxation time essentially pertain to the structural relaxation of the amorphous phase.Comment: 10 pages 12 figure
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