431 research outputs found
Absorbable stent: focus on clinical applications and benefits
Coronary stents have improved very significantly the immediate and long-term results of percutaneous coronary interventions. However, once the vessel has healed, the scaffolding function of the stent is no longer needed, and the presence of a permanent metallic prosthesis poses important disadvantages. This has led to the idea of creating new devices that are able to provide mechanical support for a determined period and then disappear from the vessel, allowing its natural healing and avoiding the risks associated with having a permanent metallic cage, such as stent thrombosis. Absorbable stents currently appear as one of the most promising fields in interventional cardiology. The present article will review the available clinical evidence regarding these devices at present and their future perspectives
Optical coherence tomography for the assessment of coronary atherosclerosis and vessel response after stent implantation
Optical Coherence Tomography (OCT) is a light-based imaging modality that can provide in vivo high-resolution images of the coronary artery with a level of resolution (axial 10-20 µm) ten times higher than intravascular ultrasound. The technique, uses low-coherent near infrarred light to create high-resolution cross sectional images of the vessel. The technology refinement achieved in the last years has made this imaging modality less procedurally demanding opening its possibilities for clinical use. The present thesis provides im
Gate induced enhancement of spin-orbit coupling in dilute fluorinated graphene
We analyze the origin of spin-orbit coupling (SOC) in fluorinated graphene
using Density Functional Theory (DFT) and a tight-binding model for the
relevant orbitals. As it turns out, the dominant source of SOC is the atomic
spin-orbit of fluorine adatoms and not the impurity induced SOC based on the
distortion of the graphene plane as in hydrogenated graphene. More
interestingly, our DFT calculations show that SOC is strongly affected by both
the type and concentrations of the graphene's carriers, being enhanced by
electron doping and reduced by hole doping. This effect is due to the charge
transfer to the fluorine adatom and the consequent change in the
fluorine-carbon bonding. Our simple tight-binding model, that includes the SOC
of the orbitals of F and effective parameters based on maximally localized
Wannier functions, is able to account for the effect. The strong enhancement of
the SOC induced by graphene doping opens the possibility to tune the spin
relaxation in this material.Comment: 9 pages, 8 figure
Grammar compressed sequences with rank/select support
An early partial version of this paper appeared in Proc. SPIRE 2014: G. Navarro, A. Ordóñez Grammar compressed sequences with rank/select support, Proc. 21st International Symposium on String Processing and Information Retrieval, LNCS, SPIRE, vol. 8799 (2014), pp. 31–44The final publication is available at Springer via http://dx.doi.org/10.1016/j.jda.2016.10.001[Abstract] Sequence representations supporting not only direct access to their symbols, but also rank/select operations, are a fundamental building block in many compressed data structures. Several recent applications need to represent highly repetitive sequences, and classical statistical compression proves ineffective. We introduce, instead, grammar-based representations for repetitive sequences, which use up to 6% of the space needed by statistically compressed representations, and support direct access and rank/select operations within tens of microseconds. We demonstrate the impact of our structures in text indexing applications.Chile. Fondo Nacional de Desarrollo CientÃfico y Tecnológico; 140796Ministerio de EconomÃa, Industria y Competitividad; 00645663/ITC-20133062Ministerio de EconomÃa, Industria y Competitividad; TIN2009-14560-C03-02Ministerio de EconomÃa, Industria y Competitividad; TIN2010-21246-C02-01Ministerio de EconomÃa, Industria y Competitividad; TIN2013-46238-C4-3-RMinisterio de EconomÃa, Industria y Competitividad; TIN2013-47090-C3-3-PMinisterio de EconomÃa, Industria y Competitividad; AP2010-6038Xunta de Galicia; GRC2013/05
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