Control of the magnetic anisotropy in multirepeat Pt/Co/Al heterostructures using magnetoionic gating

Controlling magnetic properties through the application of an electric field is a significant challenge in modern nanomagnetism. In this study, we investigate the magnetoionic control of magnetic anisotropy in the topmost Co layer in Ta/Pt/[Co/Al/Pt]n/Co/Al/AlOx multilayer stacks comprising n + 1 Co layers and its impact on the magnetic properties of the multilayers. We demonstrate that the perpendicular magnetic anisotropy can be reversibly quenched through gate-driven oxidation of the intermediary Al layer between Co and AlOx, enabling dynamic control of the magnetic layers contributing to the out-of-plane remanence— varying between n and n + 1. For multilayer configurations with n = 2 and n = 4, we observe reversible and nonvolatile additions of 1/3 and 1/5, respectively, to the anomalous Hall-effect amplitude based on the applied gate voltage. Magnetic imaging reveals that the gate-induced spin-reorientation transition occurs through the propagation of a single 90◦ magnetic domain wall separating the perpendicular and in-plane anisotropy states. In the five-repetition multilayer, the modification leads to a doubling of the period of the magnetic domains at remanence. These results demonstrate that the magnetoionic control of the anisotropy of a single magnetic layer can be used to control the magnetic properties of coupled multilayer systems, extending beyond the gating effects on a single magnetic layer

Astropy: A community Python package for astronomy

We present the first public version (v0.2) of the open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to the community, including support for domain-specific file formats such as flexibl

Registry of transcatheter aortic-valve implantation in high-risk patients.

International audienceBACKGROUND: Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2. METHODS: All TAVIs performed in France, as listed in the FRANCE 2 registry, were prospectively included in the study. The primary end point was death from any cause. RESULTS: A total of 3195 patients were enrolled between January 2010 and October 2011 at 34 centers. The mean (±SD) age was 82.7±7.2 years; 49% of the patients were women. All patients were highly symptomatic and were at high surgical risk for aortic-valve replacement. Edwards SAPIEN and Medtronic CoreValve devices were implanted in 66.9% and 33.1% of patients, respectively. Approaches were either transarterial (transfemoral, 74.6%; subclavian, 5.8%; and other, 1.8%) or transapical (17.8%). The procedural success rate was 96.9%. Rates of death at 30 days and 1 year were 9.7% and 24.0%, respectively. At 1 year, the incidence of stroke was 4.1%, and the incidence of periprosthetic aortic regurgitation was 64.5%. In a multivariate model, a higher logistic risk score on the European System for Cardiac Operative Risk Evaluation (EuroSCORE), New York Heart Association functional class III or IV symptoms, the use of a transapical TAVI approach, and a higher amount of periprosthetic regurgitation were significantly associated with reduced survival. CONCLUSIONS: This prospective registry study reflected real-life TAVI experience in high-risk elderly patients with aortic stenosis, in whom TAVI appeared to be a reasonable option. (Funded by Edwards Lifesciences and Medtronic.)

Late Outcomes of Transcatheter Aortic Valve Replacement in High-Risk Patients The FRANCE-2 Registry

International audienceBACKGROUND Transcatheter aortic valve replacement (TAVR) has revolutionized management of high-risk patients with severe aortic stenosis. However, survival and the incidence of severe complications have been assessed in relatively small populations and/or with limited follow-up. OBJECTIVES This report details late clinical outcome and its determinants in the FRANCE-2 (FRench Aortic National CoreValve and Edwards) registry. METHODS The FRANCE-2 registry prospectively included all TAVRs performed in France. Follow-up was scheduled at 30 days, at 6 months, and annually from 1 to 5 years. Standardized VARC (Valve Academic Research Consortium) outcome definitions were used. RESULTS A total of 4,201 patients were enrolled between January 2010 and January 2012 in 34 centers. Approaches were transarterial (transfemoral 73%, transapical 18%, subclavian 6%, and transaortic or transcarotid 3%) or, in 18% of patients, transapical. Median follow-up was 3.8 years. Vital status was available for 97.2% of patients at 3 years. The 3-year all-cause mortality was 42.0% and cardiovascular mortality was 17.5%. In a multivariate model, predictors of 3-year all-cause mortality were male sex (p = 2 of 4 (p < 0.001). Severe events according to VARC criteria occurred mainly during the first month and subsequently in < 2% of patients/year. Mean gradient, valve area, and residual aortic regurgitation were stable during follow-up. CONCLUSIONS The FRANCE-2 registry represents the largest database available on late results of TAVR. Late mortality is largely related to noncardiac causes. Incidence rates of severe events are low after the first month. Valve performance remains stable over time. (J Am Coll Cardiol 2016; 68: 1637-47) (C) 2016 by the American College of Cardiology Foundation