High rate of uncovered struts in latest generation drug-eluting stents with durable, biodegradable polymer or lack of it 1 month after implantation

Introduction and objectives: Delayed vascular healing may induce late stent thrombosis. Optical coherence tomography (OCT) is useful to evaluate endothelial coverage. The objective of this study was to compare stent coverage and apposition in non-complex coronary artery lesions treated with durable polymer-coated everolimus-eluting stents (durable-polymer EES) vs biodegradable polymer-coated everolimus-eluting stents ( biodegradable-polymer EES) vs polymer-free biolimus-eluting stents (BES) 1 and 6 months after stent implantation. Methods: Prospective, multicenter, non-randomized study that compared the 3 types of DES. Follow-up angiography and OCT were performed 1 and 6 months later. The primary endpoint was the rate of uncovered struts as assessed by the OCT at 1 month. Results: A total of 104 patients with de novo non-complex coronary artery lesions were enrolled. A total of 44 patients were treated with polymer-free BES, 35 with biodegradable-polymer EES, and 25 with durable-polymer EES. A high rate of uncovered struts was found at 1 month with no significant differences reported among the stents (80.2%, polymer-free BES; 88.1%, biodegradable-polymer EES; 82.5%, durable-polymer EES; P =.209). Coverage improved after 6 months in the 3 groups without significant differences being reported (97%, 95%, and 93.7%, respectively; P =.172). Conclusions: In patients with de novo non-complex coronary artery lesions treated with durable vs biodegradable vs polymer-free DES, strut coverage and apposition were suboptimal at 1 month with significant improvement at 6 months

A bibliography and webliography of Mexican Chicago

This Lab Note reflects the first stage of a three-year research project known as eChicago. This project is funded by the Institute for Museum and Library Services and the full title of the project is Chicago community informatics: Places, Uses, Resources. Our interest here is to examine the population of Chicago, in particular a subset of ethnicities and community areas, and analyze how these communities are navigating the digital age. Stage one is to understand the communities today and discover how they are represented in cyberspace. Thus our initial products include a webliography/bibliography on each community and we are honored to partner with experts on these communities.Institute of Museum and Library Servicespublished or submitted for publicatio

Crack initiation under shock loading : validation of a new testing technique

The evaluation of the dynamic fracture properties with the current impact testing techniques is subject of some controversy, because the crack initiation conditions cannot be established with accuracy. Besides, some of them are limited to low loading velocities and the evaluations are made following a static approach. In consequence, a fundamental study is required with two aims, namely, a development of a new impact testing technique and the analysis of the extension of the fracture mechanics concepts to crack initiation under dynamic loading. These are the objectives of this research project. The impact testing technique proposed is based on the shock tube technique and is capable to test the specimens, which are central cracked circular plates, under static and dynamic conditions. The findings show that the specimens are loaded uniformly with blast waves, which have an initial ramp that increases steadily without oscillations. The magnitude of the load is controllable and reproducible and the fracture analysis should be based on a dynamic calibration. This technique has been applied to the evaluation of the dynamic fracture toughness of PMMA following an experimental-numerical procedure. The crack initiation load and the strain rate were measured experimentally and the fracture toughness was calculated numerically with standard solutions and with numerical calculations of the J-Integral with the finite element code ABAQUS. The problem of crack initiation under pressure load has not been completely solved. Consequently, the significance of the static and dynamic test results was established with the findings of additional experimental and numerical work, which showed that the modulus of elasticity and fracture stress increases with the strain rate, that there is plastic deformation at the crack tip of those specimens tested under static conditions and that the dynamic calculations with ABAQUS involves the interaction of the stress waves with the boundaries. Furthermore, it has to be noticed that the crack tip is under bending stresses. Thus, this test is not a standard plane strain material dynamic test. Finally, conclusions are drawn on the use of the this experimental-numerical technique and its further application.</p