Micro- vs. macro-phase separation in binary blends of poly(styrene)-poly(isoprene) and poly(isoprene)-poly(ethylene oxide) diblock copolymers

In this paper we present an experimentally determined phase diagram of binary blends of the diblock copolymers poly(styrene)-poly(isoprene) and poly(isoprene)-poly(ethylene oxide). At high temperatures, the blends form an isotropic mixture. Upon lowering the temperature, the blend macro-phase separates before micro-phase separation occurs. The observed phase diagram is compared to theoretical predictions based on experimental parameters. In the low-temperature phase the crystallisation of the poly(ethylene oxide) block influences the spacing of the ordered phase

Longitudinal changes in functional connectivity of cortico-basal ganglia networks in manifests and premanifest huntington's disease

Huntington's disease (HD) is a genetic neurological disorder resulting in cognitive and motor impairments. We evaluated the longitudinal changes of functional connectivity in sensorimotor, associative and limbic cortico-basal ganglia networks. We acquired structural MRI and resting-state fMRI in three visits one year apart, in 18 adult HD patients, 24 asymptomatic mutation carriers (preHD) and 18 gender- and age-matched healthy volunteers from the TRACK-HD study. We inferred topological changes in functional connectivity between 182 regions within cortico-basal ganglia networks using graph theory measures. We found significant differences for global graph theory measures in HD but not in preHD. The average shortest path length (L) decreased, which indicated a change toward the random network topology. HD patients also demonstrated increases in degree k, reduced betweeness centrality bc and reduced clustering C. Changes predominated in the sensorimotor network for bc and C and were observed in all circuits for k. Hubs were reduced in preHD and no longer detectable in HD in the sensorimotor and associative networks. Changes in graph theory metrics (L, k, C and bc) correlated with four clinical and cognitive measures (symbol digit modalities test, Stroop, Burden and UHDRS). There were no changes in graph theory metrics across sessions, which suggests that these measures are not reliable biomarkers of longitudinal changes in HD. preHD is characterized by progressive decreasing hub organization, and these changes aggravate in HD patients with changes in local metrics. HD is characterized by progressive changes in global network interconnectivity, whose network topology becomes more random over time. Hum Brain Mapp, 2016. © 2016 Wiley Periodicals, Inc

Intracranial Vertebrobasilar Artery Dissection Associated with Postpartum Angiopathy

Background. Cervicocephalic arterial dissection (CCAD) is rare in the postpartum period. To our knowledge this is the first reported case of postpartum angiopathy (PPA) presenting with ischemic stroke due to intracranial arterial dissection. Case. A 41-year-old woman presented with blurred vision, headache, and generalized seizures 5 days after delivering twins. She was treated with magnesium for eclampsia. MRI identified multiple posterior circulation infarcts. Angiography identified a complex dissection extending from both intradural vertebral arteries, through the basilar artery, and into both posterior cerebral arteries. Multiple segments of arterial dilatation and narrowing consistent with PPA were present. Xenon enhanced CT (Xe-CT) showed reduced regional cerebral blood flow that is improved with elevation in blood pressure. Conclusion. Intracranial vertebrobasilar dissection causing stroke is a rare complication of pregnancy. Eclampsia and PPA may play a role in its pathogenesis. Blood pressure management may be tailored using quantitative blood flow studies, such as Xe-CT

Association Between Anxiety, Depression, and Post-traumatic Stress Disorder and Outcomes After Ischemic Stroke

Background: Stroke patients are known to be at risk of developing anxiety, depression, and post-traumatic stress disorder (PTSD).Objective: To determine the overlap between anxiety, depression, and PTSD in patients after stroke and to determine the association between these disorders and quality of life, functional status, healthcare utilization, and return to work.Methods: A cross-sectional telephone survey was conducted to assess for depression, anxiety, PTSD, and health-related outcomes 6–12 months after first ischemic stroke in patients without prior psychiatric disease at a single stroke center.Results: Of 352 eligible subjects, 55 (16%) completed surveys. Seven subjects (13%) met criteria for probable anxiety, 6 (11%) for PTSD, and 11 for depression (20%). Of the 13 subjects (24%) who met criteria for any of these disorders, 6 (46%) met criteria for more than one, and 5 (39%) met criteria for all three. There were no significant differences in baseline characteristics, including stroke severity or neurologic symptoms, between those with or without any of these disorders. Those who had any of these disorders were less likely to be independent in their activities of daily living (ADLs) (54 vs. 95%, p < 0.001) and reported significantly worse quality of life (score of 0–100, median score of 50 vs. 80, p < 0.001) compared to those with none of these disorders.Conclusions: Anxiety, depression, and PTSD are common after stroke, have a high degree of co-occurrence, and are associated with worse outcomes, including quality of life and functional status

World Stroke Organization Brain & hEart globAl iniTiative Program

Introduction. The World Stroke Organization (WSO) Brain & Heart Task Force developed The Brain & hEart globAl iniTiative (BEAT), a pilot feasibility implementation program aimed at establishing clinical collaborations between cardiologists and stroke physicians who work at large healthcare facilities. Methods. The WSO BEAT pilot project focused on atrial fibrillation (AF) and patent foramen ovale (PFO) detection and management, and post-stroke cardiovascular complications known as the stroke-heart syndrome. The program included 10 sites from 8 countries: Brazil, China, Egypt, Germany, Japan, Mexico, Romania, and the USA. The primary composite feasibility outcome was the achievement of the following 3 implementation metrics (1) developing site-specific clinical pathways for the diagnosis and management of AF, PFO, and the stroke heart syndrome; (2) establishing regular Neurocardiology rounds (e.g., monthly); and (3) incorporating a cardiologist to the stroke team. The secondary objectives were (1) to identify implementation challenges to guide a larger program and (2) to describe qualitative improvements.Results. The WSO BEAT pilot feasibility program achieved the pre-specified primary composite outcome in 9 of 10 (90%) sites. The most common challenges were the limited access to specific medications (e.g., direct oral anticoagulants) and diagnostic (e.g., prolonged cardiac monitoring) or therapeutic (e.g., PFO closure devices) technologies. The most relevant qualitative improvement was the achievement of a more homogeneous diagnostic and therapeutic approach.Discussion/Conclusion. The WSO BEAT pilot program showed that developing Neurocardiology collaborations is feasible. The long-term sustainability of the WSO BEAT program and its impact on quality of stroke care and clinical outcomes needs to be tested in a larger and longer-duration program

Failed surgical ligation of the proximal left subclavian artery during hybrid thoracic endovascular aortic repair successfully managed by percutaneous plug or coil occlusion: a report of 3 cases

Open surgical rerouting and proximal ligation of one or more supra-aortic vessels prior to endovascular stent-graft placement has become an alternative to major open thoracic surgery in the treatment of complex thoracic aortic disease. Complications owing to failed surgical ligation of the left subclavian artery are rare. In this report, 3 cases of failed ligation are presented. Diagnosis was made by CT-scan and treatment was performed by transcatheter coil and plug embolization, avoiding redo neck surgery

Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

Background: Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from prior studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesized that anticoagulant treatment with rivaroxaban, an oral factor-Xa inhibitor, would reduce the risk of recurrent stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE-ESUS trial. Methods: The NAVIGATE-ESUS double-blind, randomised trial assessed the efficacy and safety of rivaroxaban 15mg versus aspirin 100mg once daily for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined based on transthoracic(TTE) and transesophageal echocardiography(TEE). The primary efficacy outcome was time-to-recurrent ischemic stroke between treatment groups. In addition, a systematic review of the literature incorporated prior studies in which patients with cryptogenic stroke and PFO were randomly assigned to anticoagulant or antiplatelet therapy. Findings: 7213 participants were enrolled and followed for a mean of 11 months due to early trial termination. PFO was reported as present in 534 (7.4%) patients based on either TTE or TEE. Aspirinassigned patients with PFO had a recurrent stroke rate of 4.8% per year. Among patients with known PFO, there was insufficient evidence to support a difference in hazards between rivaroxaban and aspirin (HR 0.54; 95%CI:0.22-1.36), while hazards were high similar for those without known PFO (HR 1.06; 95%CI:0.84-1.33); the interaction was not statistically significant (p=0.18). Major bleeding was likely increased with rivaroxaban compared with aspirin (HR 2.05; 95%CI:0.51-8.2) in patients with PFO. Systematic review that included 2 prior trials yielded a summary odds ratio of 0.48 (95%CI:0.24-0.96; p=0.04) in favour of anticoagulation, without evidence of heterogeneity. Interpretation: Among patients with ESUS who have PFO, anticoagulation may reduce the risk of recurrent stroke by about half, though substantial imprecision remains. Dedicated trials of anticoagulation vs. antiplatelet therapy and/or PFO closure are warranted

On the Effect of Nb on the Microstructure and Properties of Next Generation Polycrystalline Powder Metallurgy Ni-Based Superalloys

Abstract The effect of Nb on the properties and microstructure of two novel powder metallurgy (P/M) Ni-based superalloys was evaluated, and the results critically compared with the Rolls-Royce alloy RR1000. The Nb-containing alloy was found to exhibit improved tensile and creep properties as well as superior oxidation resistance compared with both RR1000 and the Nb-free variant tested. The beneficial effect of Nb on the tensile and creep properties was due to the microstructures obtained following the post-solution heat treatments, which led to a higher γ′ volume fraction and a finer tertiary γ′ distribution. In addition, an increase in the anti-phase-boundary energy of the γ′ phase is also expected with the addition of Nb, further contributing to the strength of the material. However, these modifications in the γ′ distribution detrimentally affect the dwell fatigue crack-growth behavior of the material, although this behavior can be improved through modified heat treatments. The oxidation resistance of the Nb-containing alloy was also enhanced as Nb is believed to accelerate the formation of a defect-free Cr2O3 scale. Overall, both developmental alloys, with and without the addition of Nb, were found to exhibit superior properties than RR1000.This work was supported by the Rolls-Royce/EPSRC Strategic Partnership under EP/H022309/1, EP/H500375/1 and EP/ M005607/1

Motivation gains in performance groups: Paradigmatic and theoretical developments on the Köhler effect.

In contrast to many demonstrations of social loafing, relatively few studies have documented group motivation gains. One such exception was 0. Köhler's (1926, 1927) finding that team members working together did better at a taxing persistence task than would be expected from their individual performances, particularly when there was a moderate discrepancy in coworkers' capabilities. In Experiment 1, we developed a paradigm within which Köhler's overall motivation gain effect could be replicated, although the discrepancy in coworkers' capabilities did not moderate these motivation gains (after statistical artifacts were taken into account). Experiment 2 indicated that this motivation gain occurred under conjunctive but not under additive task demands, suggesting that the instrumentality of one's contribution to valued outcomes is a more likely explanation of the Köhler effect than social comparison processes