Magnification inferred curvature for real-time curvature monitoring.

The in situ and real-time measurement of curvature changes of optically reflecting surfaces is a key element to better control bottom-up fabrication processes in the semiconductor industry, but also to follow or adjust mirror deformations during fabrication and use for space or optics industries. Despite progresses made in the last two decades thanks to laser deflectometry-based techniques, the community lacks an instrument, easy to use, robust to tough environments and easily compatible with a large range of fabrication processes. We describe here a new method, called magnification inferred curvature (MIC), based on the determination of the magnification factor of the virtual image size of a known object created by a reflecting curved surface (the substrate) acting as a spherical mirror. The optical formalism, design, and proof of concept are presented. The precision, accuracy, and advantages of the MIC method are illustrated from selected examples taken from real-time growth monitoring and compared with state-of-the-art laser deflectometry-based instruments.

In Situ and Real-Time Nanoscale Monitoring of Ultra-Thin Metal Film Growth Using Optical and Electrical Diagnostic Tools.

Continued downscaling of functional layers for key enabling devices has prompted the development of characterization tools to probe and dynamically control thin film formation stages and ensure the desired film morphology and functionalities in terms of, e.g., layer surface smoothness or electrical properties. In this work, we review the combined use of in situ and real-time optical (wafer curvature, spectroscopic ellipsometry) and electrical probes for gaining insights into the early growth stages of magnetron-sputter-deposited films. Data are reported for a large variety of metals characterized by different atomic mobilities and interface reactivities. For fcc noble-metal films (Ag, Cu, Pd) exhibiting a pronounced three-dimensional growth on weakly-interacting substrates (SiO2, amorphous carbon (a-C)), wafer curvature, spectroscopic ellipsometry, and resistivity techniques are shown to be complementary in studying the morphological evolution of discontinuous layers, and determining the percolation threshold and the onset of continuous film formation. The influence of growth kinetics (in terms of intrinsic atomic mobility, substrate temperature, deposition rate, deposition flux temporal profile) and the effect of deposited energy (through changes in working pressure or bias voltage) on the various morphological transition thicknesses is critically examined. For bcc transition metals, like Fe and Mo deposited on a-Si, in situ and real-time growth monitoring data exhibit transient features at a critical layer thickness of ~2 nm, which is a fingerprint of an interface-mediated crystalline-to-amorphous phase transition, while such behavior is not observed for Ta films that crystallize into their metastable tetragonal ß-Ta allotropic phase. The potential of optical and electrical diagnostic tools is also explored to reveal complex interfacial reactions and their effect on growth of Pd films on a-Si or a-Ge interlayers. For all case studies presented in the article, in situ data are complemented with and benchmarked against ex situ structural and morphological analyses.

Outcome, Recurrence and Mortality after Non-Valvular Atrial Fibrillation Stroke: Long-Term Follow-Up Study.

OBJECTIVE: Non-valvular atrial fibrillation (NVAF) is a major risk factor for ischemic stroke (IS) and a powerful predictor of mortality. This study investigates early and long-term outcome among patients with IS secondary to NVAF and identify the main factors associated with poor outcome, recurrence, and death. METHODS: We analyzed the data from our consecutive NVAF acute IS database, over a period of 23 years. The endpoints were bad outcome (Modified Rankin Score ≥3), recurrence, and mortality at discharge, after 6 months, 12 months, and final follow-up. Multivariate Cox and Kaplan-Meier analysis were used to estimate the probability of death. RESULTS: 129 consecutive acute IS patients were included (77 [59.7%] females, mean age 70.2 ± 10.1 years). Discharge, 6 and 12 months bad outcome was 62%, 63%, and 61%, respectively. After a median follow-up of 17 months (IQR 6-54.5), 35.6% patients had bad outcome, 21.7% had recurrence and 36.4% died. The recurrence and death annual rates were 19.1% and 6.32%. The absence of oral anticoagulation (OAC) and NIHSS score > 12 were the strongest predictors of mortality. CONCLUSIONS: IS secondary to NVAF has a high rate of stroke recurrence and mortality in our population, with the absence of OAC and major stroke as the main risk factors.

Comparison of Functional Outcome and Stroke Recurrence in Patients with Embolic Stroke of Undetermined Source (ESUS) vs. Cardioembolic Stroke Patients.

BACKGROUND: Embolic stroke of undetermined source (ESUS) recurrence and functional outcome from long-term follow-up is not well delineated. The purpose of this study is to compare these functional variables between ESUS vs. cardioembolic stroke (CS) patients. METHODS: We analyzed data of consecutive ESUS and CS patients from our institutional database, from January 2003 until April 2015. The endpoints were stroke recurrence, mortality and poor clinical outcome (Modified Rankin Score 3-6), at discharge, 6 months and final follow-up. Adjusted multivariate Cox analysis and Kaplan-Meier curves were used to estimate the probability of recurrence and death. RESULTS: 149 ESUS (median age 44 years) and 235 CS (median age 66 years) consecutive patients were included in the study. Median follow-up period for the entire sample was 19 months (interquartile range 6.0-45.0 months). Stroke recurrence was similar between ESUS and CS patients (5.4% vs. 9.8% respectively, p = 0.12). Death occurred in 30 CS cases (12.8%), with a cumulative probability of survival of 77%. Poor functional outcome was present in 58.3%, 54.0% and 54.9% at discharge, 6 months and final follow-up respectively in CS patients, significantly worst compared to ESUS cases (HR 3.1; CI 95% 1.96-4.68). Oral anticoagulation presents with a HR 8.01 for recurrence, and antiplatelet therapy had the highest risk for recurrence for both groups (HR 24.3). CONCLUSION: ESUS patients are substantially younger than CS patients but have a stroke recurrence rate similar to CS patients, with a lower mortality rate, and better functional outcome on long-term follow-up.

Diabetic retinopathy (treatment).

INTRODUCTION: Diabetic retinopathy is the most common cause of blindness in the UK, with older people and those with worse diabetes control, hypertension, and hyperlipidaemia being most at risk. Diabetic retinopathy can cause microaneurysms, haemorrhages, exudates, changes to blood vessels, and retinal thickening. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people with diabetic retinopathy? What are the effects of treatments for vitreous haemorrhage? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found 58 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. CONCLUSIONS: In this systematic review we present information relating to the effectiveness and safety of the following interventions: peripheral retinal laser photocoagulation, focal and grid laser photocoagulation for maculopathy, corticosteroids for macular oedema, vascular endothelial growth factor inhibitors, and vitrectomy for vitreous haemorrhage.

New Approaches to the Computer Simulation of Amorphous Alloys: A Review.

In this work we review our new methods to computer generate amorphous atomic topologies of several binary alloys: SiH, SiN, CN; binary systems based on group IV elements like SiC; the GeSe2 chalcogenide; aluminum-based systems: AlN and AlSi, and the CuZr amorphous alloy. We use an ab initio approach based on density functionals and computationally thermally-randomized periodically-continued cells with at least 108 atoms. The computational thermal process to generate the amorphous alloys is the undermelt-quench approach, or one of its variants, that consists in linearly heating the samples to just below their melting (or liquidus) temperatures, and then linearly cooling them afterwards. These processes are carried out from initial crystalline conditions using short and long time steps. We find that a step four-times the default time step is adequate for most of the simulations. Radial distribution functions (partial and total) are calculated and compared whenever possible with experimental results, and the agreement is very good. For some materials we report studies of the effect of the topological disorder on their electronic and vibrational densities of states and on their optical properties.