Progress in the Development of SERS-Active Substrates Based on Metal-Coated Porous Silicon

The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed. Since the earliest studies, a number of fundamentally different plasmonic nanostructures including metallic dendrites, quasi-ordered arrays of metallic nanoparticles (NPs), and metallic nanovoids have been grown on porous silicon, defined by the morphology of this host material. SERS-active substrates based on porous silicon have been found to combine a high and well-reproducible signal level, storage stability, cost-effective technology and handy use. They make it possible to identify and study many compounds including biomolecules with a detection limit varying from milli- to femtomolar concentrations. The progress reviewed here demonstrates the great prospects for the extensive use of the metal-coated porous silicon for bioanalysis by SERS-spectroscopy

Chalcogenide Thin Films—Holographic Media for Augmented Reality Devices

Holographic characteristics of chalcogenide film materials with a typical thickness of 0.5–1.5 µm of a number of Ge-S and As-S compositions have been studied theoretically and experimentally with the aim of using them in augmented reality waveguide devices. The possibility of controlling the spectral and holographic properties of materials by varying their composition is shown. The recording of both volume and surface holographic elements operating in the total internal reflection mode was carried out. The operation of holograms in the “periscope mode” with a diffraction efficiency of about 10% is demonstrated. It is concluded that the recording of high-performance holographic elements on chalcogenide films requires significant values of exposure energy when recording in the near UV range (325–355 nm), which makes holographic recording currently ineffective for creating such elements

Apixaban compared with warfarin in patients with atrial fibrillation and previous stroke or transient ischaemic attack: A subgroup analysis of the ARISTOTLE trial

Background: In the ARISTOTLE trial, the rate of stroke or systemic embolism was reduced by apixaban compared with warfarin in patients with atrial fibrillation (AF). Patients with AF and previous stroke or transient ischaemic attack (TIA) have a high risk of stroke. We therefore aimed to assess the efficacy and safety of apixaban compared with warfarin in prespecified subgroups of patients with and without previous stroke or TIA. Methods: Between Dec 19, 2006, and April 2, 2010, patients were enrolled in the ARISTOTLE trial at 1034 clinical sites in 39 countries. 18 201 patients with AF or atrial flutter were randomly assigned to receive apixaban 5 mg twice daily or warfarin (target international normalised ratio 2·0-3·0). The median duration of follow-up was 1·8 years (IQR 1·4-2·3). The primary efficacy outcome was stroke or systemic embolism, analysed by intention to treat. The primary safety outcome was major bleeding in the on-treatment population. All participants, investigators, and sponsors were masked to treatment assignments. In this subgroup analysis, we estimated event rates and used Cox models to compare outcomes in patients with and without previous stroke or TIA. The ARISTOTLE trial is registered with ClinicalTrials.gov, number NTC00412984. Findings: Of the trial population, 3436 (19%) had a previous stroke or TIA. In the subgroup of patients with previous stroke or TIA, the rate of stroke or systemic embolism was 2·46 per 100 patient-years of follow-up in the apixaban group and 3·24 in the warfarin group (hazard ratio [HR] 0·76, 95% CI 0·56 to 1·03); in the subgroup of patients without previous stroke or TIA, the rate of stroke or systemic embolism was 1·01 per 100 patient-years of follow-up with apixaban and 1·23 with warfarin (HR 0·82, 95% CI 0·65 to 1·03; p for interaction=0·71). The absolute reduction in the rate of stroke and systemic embolism with apixaban versus warfarin was 0·77 per 100 patient-years of follow-up (95% CI -0·08 to 1·63) in patients with and 0·22 (-0·03 to 0·47) in those without previous stroke or TIA. The difference in major bleeding with apixaban compared with warfarin was 1·07 per 100 patient-years (95% CI 0·09-2·04) in patients with and 0·93 (0·54-1·32) in those without previous stroke or TIA. Interpretation: The effects of apixaban versus warfarin were consistent in patients with AF with and without previous stroke or TIA. Owing to the higher risk of these outcomes in patients with previous stroke or TIA, the absolute benefits of apixaban might be greater in this population. Funding: Bristol-Myers Squibb and Pfizer. © 2012 Elsevier Ltd

Apixaban versus warfarin in patients with atrial fibrillation

BACKGROUND: Vitamin K antagonists are highly effective in preventing stroke in patients with atrial fibrillation but have several limitations. Apixaban is a novel oral direct factor Xa inhibitor that has been shown to reduce the risk of stroke in a similar population in comparison with aspirin. METHODS: In this randomized, double-blind trial, we compared apixaban (at a dose of 5 mg twice daily) with warfarin (target international normalized ratio, 2.0 to 3.0) in 18,201 patients with atrial fibrillation and at least one additional risk factor for stroke. The primary outcome was ischemic or hemorrhagic stroke or systemic embolism. The trial was designed to test for noninferiority, with key secondary objectives of testing for superiority with respect to the primary outcome and to the rates of major bleeding and death from any cause. RESULTS: The median duration of follow-up was 1.8 years. The rate of the primary outcome was 1.27% per year in the apixaban group, as compared with 1.60% per year in the warfarin group (hazard ratio with apixaban, 0.79; 95% confidence interval [CI], 0.66 to 0.95; P<0.001 for noninferiority; P = 0.01 for superiority). The rate of major bleeding was 2.13% per year in the apixaban group, as compared with 3.09% per year in the warfarin group (hazard ratio, 0.69; 95% CI, 0.60 to 0.80; P<0.001), and the rates of death from any cause were 3.52% and 3.94%, respectively (hazard ratio, 0.89; 95% CI, 0.80 to 0.99; P = 0.047). The rate of hemorrhagic stroke was 0.24% per year in the apixaban group, as compared with 0.47% per year in the warfarin group (hazard ratio, 0.51; 95% CI, 0.35 to 0.75; P<0.001), and the rate of ischemic or uncertain type of stroke was 0.97% per year in the apixaban group and 1.05% per year in the warfarin group (hazard ratio, 0.92; 95% CI, 0.74 to 1.13; P = 0.42). CONCLUSIONS: In patients with atrial fibrillation, apixaban was superior to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality. Copyright © 2011 Massachusetts Medical Society. All rights reserved