12,315 research outputs found

    Rupture of the arterial wall causes deflection in pressure time course during ex vivo balloon angioplasty

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    A relation between restenosis and arterial lesions resulting from balloon angioplasty has been suggested in literature. Nevertheless, it is unclear to what extent angioplasty-induced arterial wall lesions contribute to the occurrence of restenosis. One problem is that arterial ruptures cannot be detected during balloon inflation. This study describes a method to detect ruptures in the arterial wall, based on deflections observable in the development of the balloonpressure. We performed ex vivo angioplasty with constant strain rate on 28 human femoral artery segments, showing deflections in 21 cases. In 20 cases wall rupture was confirmed histologically. From seven cases not showing deflections, four showed intact wall at microscopy. These figures result in a selectivity of the proposed method of 87 ± 7% and a predictive value of the positive test of 95 ± 5%. We conclude that this method can enhance detection of arterial rupture during ex vivo angioplasty and may become important clinically

    A Meta-Analysis of Procedures to Change Implicit Measures

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    Using a novel technique known as network meta-analysis, we synthesized evidence from 492 studies (87,418 participants) to investigate the effectiveness of procedures in changing implicit measures, which we define as response biases on implicit tasks. We also evaluated these procedures’ effects on explicit and behavioral measures. We found that implicit measures can be changed, but effects are often relatively weak (|ds| \u3c .30). Most studies focused on producing short-term changes with brief, single-session manipulations. Procedures that associate sets of concepts, invoke goals or motivations, or tax mental resources changed implicit measures the most, whereas procedures that induced threat, affirmation, or specific moods/emotions changed implicit measures the least. Bias tests suggested that implicit effects could be inflated relative to their true population values. Procedures changed explicit measures less consistently and to a smaller degree than implicit measures and generally produced trivial changes in behavior. Finally, changes in implicit measures did not mediate changes in explicit measures or behavior. Our findings suggest that changes in implicit measures are possible, but those changes do not necessarily translate into changes in explicit measures or behavior

    Removing black-hole singularities with nonlinear electrodynamics

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    We propose a way to remove black hole singularities by using a particular nonlinear electrodynamics Lagrangian that has been recently used in various astrophysics and cosmological frameworks. In particular, we adapt the cosmological analysis discussed in a previous work to the black hole physics. Such analysis will be improved by applying the Oppenheimer-Volkoff equation to the black hole case. At the end, fixed the radius of the star, the final density depends only on the introduced quintessential density term ργ\rho_{\gamma} and on the mass.Comment: In this last updated version we correct two typos which were present in Eqs. (21) and (22) in the version of this letter which has been published in Mod. Phys. Lett. A 25, 2423-2429 (2010). In the present version, both of Eqs. (21) and (22) are dimensionally and analytically correc

    Deformation of Silica Aerogel During Fluid Adsorption

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    Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.Comment: 8 pages, 5 figures, submitted to PR
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