17 research outputs found

    Panorama das Intervenções Coronárias Percutâneas em Oclusões Totais Crônicas em Centros Participantes do LATAM CTO Registry no Brasil

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    Background: Major advances have been seen in techniques and devices for performing percutaneous coronary interventions (PCIs) for chronic total occlusions (CTOs), but there are limited real-world practice data from developing countries. Objectives: To report clinical and angiographic characteristics, procedural aspects, and clinical outcomes of CTO PCI performed at dedicated centers in Brazil. Methods: Included patients underwent CTO PCI at centers participating in the LATAM CTO Registry, a Latin American multicenter registry dedicated to prospective collection of these data. Inclusion criteria were procedures performed in Brazil, age 18 years or over, and presence of CTO with PCI attempt. CTO was defined as a 100% lesion in an epicardial coronary artery, known or estimated to have lasted at least 3 months. Results: Data on 1196 CTO PCIs were included. Procedures were performed primarily for angina control (85%) and/or treatment of moderate/severe ischemia (24%). Technical success rate was 84%, being achieved with antegrade wire approaches in 81% of procedures, antegrade dissection and re-entry in 9%, and retrograde approaches in 10%. In-hospital adverse cardiovascular events occurred in 2.3% of cases, with a mortality rate of 0.75%. Conclusions: CTOs can be treated effectively in Brazil by using PCI, with low complication rates. The scientific and technological development observed in this area in the past decade is reflected in the clinical practice of dedicated Brazilian centersinfo:eu-repo/semantics/publishedVersio

    Atomic force microscopy surface analysis of thin polyaniline films deposited on different substrata

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    Este trabalho apresenta um estudo sobre a morfologia de filmes finos de polianilina, fabricados por diferentes processos e depositados sobre diferentes substratos pela técnica de microscopia de força atômica (AFM). Os processos usados para a fabricação dos filmes foram o de espalhamento fluido, o de centrifugação, o de auto montagem e o eletroquímico. Os substratos usados foram: vidro, ouro/cromo/vidro, quartzo, ITO, silício e mica. Além da análise visual da qualidade dos filmes, ou seja, do grau de recobrimento do substrato e da uniformidade dos filmes, foram feitas análises de parâmetros quantitativos através de medidas de rugosidade. Usando modelos de crescimento como o de deposição balística e de análise de rugosidade, como o da densidade do espectro de potência, (transformada de Fourier da rugosidade da imagem em função da freqüência espectral) em superfícies auto-afins, foram obtidos parâmetros como: expoente de rugosidade, comprimento característico de correlação e dimensão fractal. Apesar dos filmes de polianilina serem sistemas extremamente complexos, - compostos de macromoléculas formando uma estrutura semicristalina - os parâmetros obtidos por esses modelos, que foram elaborados para sistemas bem mais simples, deram resultados muito bons e auto-coerentes. Como conclusão, mostramos que a conjuminação da técnica de microscopia de força atômica com esses modelos compõem um método poderoso para o estudo de filmes finos orgânicos.This work presents a detailed study about the characteristic of thin films of polyaniline, fabricated by different methods and deposited over different substrates using Atomic Force Microscopy technique (AFM). The processes used for film depositions were casting, spin-coating, self-assembly, and the electrochemistry methods. The substrata used were: glass plates, gold/chromium/glass, quartz, ITO, silicon, and mica. Besides the visual analysis, that observes the film uniformity and verifies the coating degree of the substratum, the application of some mathematical models was employed to obtain quantitative parameters about the roughness of the film surfaces. From the ballistic deposition model, developed to explain growing processes, and the power spectrum density that takes the Fourier transform of the roughness in function of the spectral frequency, both developed for self-affine surfaces, it was obtained parameters as: the roughness exponent, the correlation characteristic length, and the fractal dimension. Despite the highly complex structure of the polyaniline - composed by macromolecules forming a semicrystalline structure- the obtained parameters by such models developed for very simple systems, provided reasonable and self-coherent results. As a final result of this work we showed that the synergy between the AFM technique and the above mentioned models compose a powerful method for the study of thin organic films

    Atomic force microscopy surface analysis of thin polyaniline films deposited on different substrata

    No full text
    Este trabalho apresenta um estudo sobre a morfologia de filmes finos de polianilina, fabricados por diferentes processos e depositados sobre diferentes substratos pela técnica de microscopia de força atômica (AFM). Os processos usados para a fabricação dos filmes foram o de espalhamento fluido, o de centrifugação, o de auto montagem e o eletroquímico. Os substratos usados foram: vidro, ouro/cromo/vidro, quartzo, ITO, silício e mica. Além da análise visual da qualidade dos filmes, ou seja, do grau de recobrimento do substrato e da uniformidade dos filmes, foram feitas análises de parâmetros quantitativos através de medidas de rugosidade. Usando modelos de crescimento como o de deposição balística e de análise de rugosidade, como o da densidade do espectro de potência, (transformada de Fourier da rugosidade da imagem em função da freqüência espectral) em superfícies auto-afins, foram obtidos parâmetros como: expoente de rugosidade, comprimento característico de correlação e dimensão fractal. Apesar dos filmes de polianilina serem sistemas extremamente complexos, - compostos de macromoléculas formando uma estrutura semicristalina - os parâmetros obtidos por esses modelos, que foram elaborados para sistemas bem mais simples, deram resultados muito bons e auto-coerentes. Como conclusão, mostramos que a conjuminação da técnica de microscopia de força atômica com esses modelos compõem um método poderoso para o estudo de filmes finos orgânicos.This work presents a detailed study about the characteristic of thin films of polyaniline, fabricated by different methods and deposited over different substrates using Atomic Force Microscopy technique (AFM). The processes used for film depositions were casting, spin-coating, self-assembly, and the electrochemistry methods. The substrata used were: glass plates, gold/chromium/glass, quartz, ITO, silicon, and mica. Besides the visual analysis, that observes the film uniformity and verifies the coating degree of the substratum, the application of some mathematical models was employed to obtain quantitative parameters about the roughness of the film surfaces. From the ballistic deposition model, developed to explain growing processes, and the power spectrum density that takes the Fourier transform of the roughness in function of the spectral frequency, both developed for self-affine surfaces, it was obtained parameters as: the roughness exponent, the correlation characteristic length, and the fractal dimension. Despite the highly complex structure of the polyaniline - composed by macromolecules forming a semicrystalline structure- the obtained parameters by such models developed for very simple systems, provided reasonable and self-coherent results. As a final result of this work we showed that the synergy between the AFM technique and the above mentioned models compose a powerful method for the study of thin organic films

    Scanning Electron Microscopy

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    Thermoluminescence, structural and magnetic properties of a Li(2)O-B(2)O(3)-Al(2)O(3) glass system doped with LiF and TiO(2)

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    A Li(2)O-B(2)O(3)-Al(2)O(3) glass system, un-doped and doped with LiF, and/or TiO(2) was synthesized by the fusion method and its physical properties were investigated by thermoluminescence (TL), X-ray diffraction (XRD), electron paramagnetic resonance (EPR), atomic force microscopy (AFM) and differential thermal analysis (DTA). The samples were subjected to gamma-rays from a colbalt-60 ((60)Co) source. These techniques provided evidence of LiF and LiF doped with Ti crystal formation in the glass system. A TL glow peak at about 433 K was sensitive to (60)Co gamma-rays and showed good linearity with doses and consequently could be used to quantify radiation doses. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.Brazilian agency: CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Brazilian agency: FAPEMIGCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Brazilian agency: CAPE

    Effect of Mn concentration and atomic structure on the magnetic properties of Ge thin films

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    This work reports on the magnetic properties of Ge(100-x)Mn(x) (x=0-24 at. %) films prepared by cosputtering a Ge+Mn target and submitted to cumulative thermal annealing treatments up to 500 degrees C. Both as-deposited and annealed films were investigated by means of compositional analysis, Raman scattering spectroscopy, magnetic force microscopy, superconducting quantum interference device magnetometry, and electrical resistivity measurements. All as-deposited films (either pure or containing Mn) exhibit an amorphous structure, which changes to crystalline as the annealing treatments are performed at increasing temperatures. In fact, the magnetic properties of the present Ge(100-x)Mn(x) films are very sensitive to the Mn content and whether their atomic structure is amorphous or crystalline. More specifically: whereas the amorphous Ge(100-x)Mn(x) films (with high x) present a characteristic spin glass behavior at low temperature; after crystallization, the films (with moderate Mn contents) are ferromagnetic at room temperature. Moreover, the magnetic behavior of the films scales with their Mn concentration and tends to be more pronounced after crystallization. Finally, the semiconducting behavior of the films, experienced by previous optical studies, was confirmed through electrical measurements, which also indicate the dependence of the resistivity with the atomic composition of the films. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3520661]FAPESPCNP

    Dynamic formation of SEBS copolymer submicrometric structures.

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    Highly ordered AeBeA block copolymer arrangements in the submicrometric scale, resulting from dewetting and solvent evaporation of thin films, have inspired a variety of new applications in the nanometric world. Despite the progress observed in the control of such structures, the intricate scientific phenomena related to regular patterns formation are still not completely elucidated. SEBS is a standard example of a triblock copolymer that forms spontaneously impressive pattern arrangements. From macroscopic thin liquid films of SEBS solution, several physical effects and phenomena act synergisticallyto achieve well-arranged patterns of stripes and/or droplets. That is, concomitant with dewetting, solvent evaporation, and Marangoni effect, Rayleigh instability and phase separation also play important role in the pattern formation. These two last effects are difficult to be followed experimentally in the nanoscale, which render difficulties to the comprehension of the whole phenomenon. In this paper, we use computational methods for image analysis, which provide quantitative morphometric data of the patterns, specifically comprising stripes fragmentation into droplets. With the help of these computational techniques, we developed an explanation for the final part of the pattern formation, i.e. structural dynamics related to the stripes fragmentation

    Titanium surface topography after brushing with fluoride and fluoride-free toothpaste simulating 10 years of use

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    Objectives: To conduct a controlled study contrasting titanium surface topography after procedures that simulated 10 years of brushing using toothpastes with or without fluoride. Methods: Commercially pure titanium (cp Ti) and Ti-6Al-4V disks (6 mm circle divide x 4 mm) were mirror-polished and treated according to 6 groups (n = 6) as a function of immersion (I) or brushing (B) using deionised water (W), fluoride-free toothpaste (T) and fluoride toothpaste (FT). Surface topography was evaluated at baseline (pretreatment) and post-treatment, using atomic force microscope in order to obtain three-dimensional images and mean roughness. Specimens submitted to immersion were submerged in the vehicles without brushing. For brushed specimens, procedures were conducted using a linear brushing machine with a soft-bristled toothbrush. Immersion and brushing were performed for 244 h. IFT and BFT samples were analysed under scanning electron microscope with Energy-Dispersive X-ray Spectroscopy (EDS). Pre and post-treatment values were compared using the paired Student T-test (alpha = .05). Intergroup comparisons were conducted using one-way ANOVA with Tukey post-test (alpha = .05). Results: cp Ti mean roughness (in nanometers) comparing pre and post-treatment were: IW, 2.29 +/- 0.55/2.33 +/- 0.17; IT, 2.24 +/- 0.46/2.02 +/- 0.38; IFT, 2.22 +/- 0.53/1.95 +/- 0.36; BW, 2.22 +/- 0.42/3.76 +/- 0.45; BT, 2.27 +/- 0.55/16.05 +/- 3.25; BFT, 2.27 +/- 0.51/22.39 +/- 5.07. Mean roughness (in nanometers) measured in Ti-6Al-4V disks (pre/post-treatment) were: IW, 1.79 +/- 0.25/2.01 +/- 0.25; IT, 1.61 +/- 0.13/1.74 +/- 0.19; IFT, 1.92 +/- 0.39/2.29 +/- 0.51; BW, 2.00 +/- 0.71/2.05 +/- 0.43; BT, 2.37 +/- 0.86/11.17 +/- 2.29; BFT, 1.83 +/- 0.50/15.73 +/- 1.78. No significant differences were seen after immersions (p > .05). Brushing increased the roughness of cp Ti and of Ti-6Al-4V (p < .01); cp Ti had topographic changes after BW, BT and BFT treatments whilst Ti-6Al-4V was significantly different only after BT and BTF. EDS has not detected fluoride or sodium ions on metal surfaces. Conclusions: Exposure to toothpastes (immersion) does not affect titanium per se; their use during brushing affects titanium topography and roughness. The associated effects of toothpaste abrasives and fluorides seem to increase roughness on titanium brushed surfaces. (C) 2012 Elsevier Ltd. All rights reserved.CNPQCNPqState of Sao Paulo Research Foundation (FAPESP)FAPESP (State of Sao Paulo Research Foundation) [08/028710
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