A morphological study of retinal changes in unilateral amblyopia using optical coherence tomography image segmentation.

OBJECTIVE: The purpose of this study was to evaluate the possible structural changes of the macula in patients with unilateral amblyopia using optical coherence tomography (OCT) image segmentation. PATIENTS AND METHODS: 38 consecutive patients (16 male; mean age 32.4+/-17.6 years; range 6-67 years) with unilateral amblyopia were involved in this study. OCT examinations were performed with a time-domain OCT device, and a custom-built OCT image analysis software (OCTRIMA) was used for OCT image segmentation. The axial length (AL) was measured by a LenStar LS 900 device. Macular layer thickness, AL and manifest spherical equivalent refraction (MRSE) of the amblyopic eye were compared to that of the fellow eye. We studied if the type of amblyopia (strabismus without anisometropia, anisometropia without strabismus, strabismus with anisometropia) had any influence on macular layer thickness values. RESULTS: There was significant difference between the amblyopic and fellow eyes in MRSE and AL in all subgroups. Comparing the amblyopic and fellow eyes, we found a statistically significant difference only in the thickness of the outer nuclear layer in the central region using linear mixed model analysis keeping AL and age under control (p = 0.032). There was no significant difference in interocular difference in the thickness of any macular layers between the subgroups with one-way between-groups ANCOVA while statistically controlling for interocular difference in AL and age. CONCLUSIONS: According to our results there are subtle changes in amblyopic eyes affecting the outer nuclear layer of the fovea suggesting the possible involvement of the photoreceptors. However, further studies are warranted to support this hypothesis

Atherosclerotic Plaques in the Aortic Arch and Subclinical Cerebrovascular Disease

Background and purposeAortic arch plaque (AAP) is a risk factor for ischemic stroke, but its association with subclinical cerebrovascular disease is not established. We investigated the association between AAP and subclinical cerebrovascular disease in an elderly stroke-free community-based cohort.MethodsThe CABL study (Cardiovascular Abnormalities and Brain Lesions) was designed to investigate cardiovascular predictors of silent cerebrovascular disease in the elderly. AAPs were assessed by suprasternal transthoracic echocardiography in 954 participants. Silent brain infarcts and white matter hyperintensity volume (WMHV) were assessed by brain magnetic resonance imaging. The association of AAP thickness with silent brain infarcts and WMHV was evaluated by logistic regression analysis.ResultsMean age was 71.6±9.3 years; 63% were women. AAP was present in 658 (69%) subjects. Silent brain infarcts were detected in 138 participants (14.5%). In multivariate analysis adjusted for potential confounders, AAP thickness and large AAP (≥4 mm in thickness) were significantly associated with the upper quartile of WMHV (WMHV-Q4; odds ratio =1.17; 95% confidence interval, 1.04-1.32; P=0.009 and odds ratio =1.79; 95% confidence interval, 1.40-3.09; P=0.036, respectively), but not with silent brain infarcts (odds ratio =1.08; 95% confidence interval, 0.94-1.23; P=0.265 and odds ratio =1.46; 95% confidence interval, 0.77-2.77; P=0.251, respectively).ConclusionsAortic arch atherosclerosis was associated with WMHV in a stroke-free community-based elderly cohort. This association was stronger in subjects with large plaques and independent of cardiovascular risk factors. Aortic arch assessment by transthoracic echocardiography may help identify subjects at higher risk of subclinical cerebrovascular disease, who may benefit from aggressive stroke risk factors treatment

Ultrafine grained plates of Al-Mg-Si alloy obtained by Incremental Equal Channel Angular Pressing : microstructure and mechanical properties

In this study, an Al-Mg-Si alloy was processed using via Incremental Equal Channel Angular Pressing (I-ECAP) in order to obtain homogenous, ultrafine grained plates with low anisotropy of the mechanical properties. This was the first attempt to process an Al-Mg-Si alloy using this technique. Samples in the form of 3 mm-thick square plates were subjected to I-ECAP with the 90˚ rotation around the axis normal to the surface of the plate between passes. Samples were investigated first in their initial state, then after a single pass of I-ECAP and finally after four such passes. Analyses of the microstructure and mechanical properties demonstrated that the I-ECAP method can be successfully applied in Al-Mg-Si alloys. The average grain size decreased from 15 - 19 µm in the initial state to below 1 µm after four I-ECAP passes. The fraction of high angle grain boundaries in the sample subjected to four I-ECAP passes lay within 53-57 % depending on the examined plane. The mechanism of grain refinement in Al-Mg-Si alloy was found to be distinctly different from that in pure aluminium with the grain rotation being more prominent than the grain subdivision, which was attributed to lower stacking fault energy and the reduced mobility of dislocations in the alloy. The ultimate tensile strength increased more than twice, whereas the yield strength - more than threefold. Additionally, the plates processed by I-ECAP exhibited low anisotropy of mechanical properties (in plane and across the thickness) in comparison to other SPD processing methods, which makes them attractive for further processing and applications

Environmentalism in the EU-28 context: the impact of governance quality on environmental energy efficiency

Environmental policies are a significant cornerstone of a developed economy, but the question that arises is whether such policies lead to a sustainable growth path. It is clear that the energy sector plays a pivotal role in environmental policies, and although the current literature has focused on examining the link between energy consumption and economic growth through an abundance of studies, it does not explicitly consider the role of institutional or governance quality variables in the process. Both globalization and democracy are important drivers of sustainability, while environmentalism is essential for the objective of gaining a “better world.” Governance quality is expected to be the key, not only for economic purposes but also for the efficiency of environmental policies. To that end, the analysis in this paper explores the link between governance quality and energy efficiency for the EU-28 countries, spanning the period 1995 to 2014. The findings document that there is a nexus between energy efficiency and income they move together: the most efficient countries are in the group with higher GDP per capita. Furthermore, the results show that governance quality is an important driver of energy efficiency and, hence, of environmental policies.University of Granad

A Fuzzy Logic Based Adaptive Whitening for Blind Channel Equalization

The use of a blind adaptive whitening filter to improve performance of a blind equalizer adapted by the constant modulus algorithm (CMA) is investigated in this paper. Since the desired performance can not be achieved by the least mean squares (LMS) algorithm for linear estimation in adaptive whitening filter, it is aimed that a fuzzy logic is adapted to increase convergence rate. The simulation results show that the proposed method increases die performance of blind equalizer significantly with whitening filter adapted by LMS algorithm