Browsing by Author "Martínez, A"

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    Oral rapamycin to prevent human coronary stent restenosis
    (2004) Guarda, E; Marchant, E; Fajuri, A; Martínez, A; Morán, S; Mendez, M; Uriarte, P; Valenzuela, E; Lazen, R
    Background Recent human trials with rapamycin-eluting stents have shown very low restenosis rates. However, the high costs of these devices preclude their use in routine angioplasty, especially when considering multiple stenting. We evaluated whether orally administered rapamycin inhibits in-stent neointimal growth in patients with unstable angina.
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    Relation of stenting to decreased coronary blood flow during primary angioplasty in acute myocardial infarction
    (2001) Escobar, J; Guarda, E; Marchant, E; Fajuri, A; Martínez, A; Pichard, A
    In primary angioplasty of acute myocardial infarction, stent implantation decreased coronary blood flow in a third of patients, caused no change in another third, and improved coronary blood flow in the last third.
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    Uncertainty analysis of displacements measured by in-plane electronic speckle-pattern interferometry with spherical wave fronts
    (2005) Martínez, A; Cordero, R; Rayas, JA; Puga, HJ; Rodríguez-Vera, R
    Displacement measurements by optical interferometry depend on the induced phase difference and on the interferometer's sensitivity vector; the latter depends in turn on the illuminating sources and on the geometry of the optical arrangement. We have performed an uncertainty analysis of the in-plane displacements measured by electronic speckle-pattern interferometry with spherical incident wave fronts. We induced the displacements by applying a uniaxial tensile load on a nominally flat elastic sample. We approached the displacement uncertainty by propagating the uncertainties that we considered reasonable to assign to the measured phase difference and to the characteristic parameters of the interferometer's sensitivity vector. Special attention was paid to evaluating contributions to the displacement uncertainty. Moreover, we observed that the uncertainty decreases if the angles of incidence and the source-target distances are increased. (C) 2005 Optical Society of America.
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    Uncertainty evaluation of displacements measured by electronic speckle-pattern interferometry
    (2004) Cordero, RR; Martínez, A; Rodríguez-Vera, R; Roth, P
    We have applied electronic speckle-pattern interferometry (ESPI), a whole-field optical technique, to measure the displacements induced by applying tensile load on a metallic sheet sample. because we used a dual-beam ESPI interferometer with collimated incident beams, our measurements were affected by errors in the collimation and in the alignment of the illuminating beams of the optical setup. In this paper, the influences of these errors are characterized and compared with other systematic effects through an uncertainty analysis. We found that the displacement uncertainty depends strongly on the incidence angles of the illuminating beams of the interferometer. Moreover, faults in the alignment of the incident beams have more influence on the uncertainty than errors in their collimation. The latter errors change the incident beams from collimated to slightly divergent, modifying in turn the interferometer sensitivity. We found that this sensitivity change can be generally neglected. (C) 2004 Elsevier B.V. All rights reserved.