Association of fluid-attenuated inversion recovery vascular hyperintensity with ischaemic events in internal carotid artery or middle cerebral artery occlusion

Background and purpose Individuals with intracranial artery occlusion have high rates of ischaemic events and recurrence.It has been challenging to identify patients who had high-risk stroke using a simple,valid and non-invasive screening approach.This study aimed to investigate whether fluid-attenuated inversion recovery(FLAIR)vascular hyperintensity(FVH),a specific imaging sign on the FLAIR sequence,could be a predictor of ischaemic events in a population with internal carotid artery(ICA)or middle cerebral artery(MCA)occlusion.Methods We retrospectively analysed 147 patients(mean 60.43±12.83 years)with 149 lesions,including 37 asymptomatic and 112 symptomatic cases of ICA or MCA occlusion.Symptomatic occlusion was considered if ischaemic events were present in the relevant territory within 90 days.FVH Alberta Stroke Program Early Computed Tomography Score(FVH-ASPECTS:0-7,with 0 indicating absence of FVH and 7 suggesting prominent FVH)and collateral circulation grade were assessed for each participant.Multivariable logistic regression analysis was performed to detect independent markers associated with symptomatic status.Results A lower FVH-ASPECTS was associated with a more favourable collateral circulation grade(rho=−0.464,p<0.0001).The FVH-ASPECTS was significantly lower in the asymptomatic occlusion group than in the symptomatic occlusion group(p<0.0001).FVH-ASPECTS(Odd ratio,2.973;95%confidence interval,1.849 to 4.781;p<0.0001)was independently associated with symptomatic status after adjustment for age,sex,lesion location and collateral circulation grade in the multivariate logistic regression.The area under the curve was 0.861 for the use of FVH-ASPECTS to identify symptomatic occlusion.Conclusions The ability to discriminate symptomatic from asymptomatic occlusion suggests that FVH may be a predictor of stroke.As a simple imaging sign,FVH may serve as a surrogate for haemodynamic impairments and can be used to identify high-risk stroke cases early in ICA or MCA occlusion.

Smart light-responsive hierarchical metal organic frameworks constructed mixed matrix membranes for efficient gas separation

One type of new light-responsive hierarchical metal organic framework(MOF) has been successfully prepared using Co(NO_(3))_(3)·6H_(2)O as the metal salt and 4,4’-azobenzenedicarboxylic acid as the ligand by microwave method for the first time. It is found that MOF [Co(Az DC)] exhibits a light-responsive characteristic to SO_(2)adsorption due to the presence of azo group from the ligand. The light-responsive hierarchical MOFs are incorporated into Matrimid■ 5218(PI) matrix to prepare mixed matrix membranes(MMMs) for gas separation application. The morphology, crystallinity, chain mobility and thermal stability of MMMs are explored. Results show that Co(Az DC) may elevate both the CO_(2)(SO_(2)) permeability and CO_(2)(SO_(2))/N_(2)selectivity of the MMMs. In particular,the Co(Az DC) doped MMMs exhibit the significantly improved CO_(2)(SO_(2))/N_(2)selectivity from 33(123) for PI control membrane to 78(420) for MMMs, overcoming the 2008 Robeson upper bound for CO_(2)/N_(2)system. Sizesieving effect of Co(Az DC) with pore size 0.35 nm enhances the selectivity, while the –N=N– group from Co(Az DC) shows affinity to CO_(2)molecular rather than N_(2), also elevating selectivity of MMMs. In brief, enhanced selectivity of high-performance membrane is attributed to incorporation of Co(Az DC) particles, which displays synergistic effects both in size-sieving and CO_(2)-philic interaction for CO_(2)/N_(2)separation. Smart highly selective interface is constructed in MMMs by switching the configuration of MOFs from cis to trans. The SO_(2)permeability and SO_(2)/N_(2)selectivity of MMMs are investigated under both visible light and ultraviolet light states, and the SO_(2)/N_(2)separation performance under visible light is notably improved in comparison with that under ultraviolet light state.