Chronic brain changes including WMCs, MTLA, and AD pathology are associated with incident dementia after stroke/TIA. Interventions targeting these chronic brain changes may reduce burden of vascular cognitive impairment.

Background and Purpose— It was recently demonstrated that cerebral microinfarcts (CMIs) can be detected in vivo using 3.0 tesla (T) magnetic resonance imaging. We investigated the prevalence, risk factors, and the longitudinal cognitive consequence of cortical CMIs on 3.0T magnetic resonance imaging, in patients with ischemic stroke or transient ischemic attack. Methods— A total of 231 patients undergoing 3.0T magnetic resonance imaging were included. Montreal Cognitive Assessment was used to evaluate global cognitive functions and cognitive domains (memory, language, and attention visuospatial and executive functions). Cognitive changes were represented by the difference in Montreal Cognitive Assessment score between baseline and 28-month after stroke/transient ischemic attack. The cross-sectional and longitudinal associations between cortical CMIs and cognitive functions were explored using ANCOVA and regression models. Results— Cortical CMIs were observed in 34 patients (14.7%), including 13 patients with acute (hyperintense on diffusion-weighted imaging) and 21 with chronic CMIs (isointense on diffusion-weighted imaging). Atrial fibrillation was a risk factor for all cortical CMIs (odds ratio, 4.8; 95% confidence interval, 1.5–14.9; P =0.007). Confluent white matter hyperintensities was associated with chronic CMIs (odds ratio, 2.8; 95% confidence interval, 1.0–7.8; P =0.047). The presence of cortical CMIs at baseline was associated with worse visuospatial functions at baseline and decline over 28-month follow-up (β=0.5; 95% confidence interval, 0.1–1.0; P =0.008, adjusting for brain atrophy, white matter hyperintensities, lacunes, and microbleeds). Conclusions— Cortical CMIs are a common finding in patients with stroke/transient ischemic attack. Associations between CMI with atrial fibrillation and white matter hyperintensities suggest that these lesions have a heterogeneous cause, involving microembolism and cerebral small vessel disease. CMI seemed to preferentially impact visuospatial functions as assessed by a cognitive screening test.

C ognitive impairment in the context of stroke or transient ischemic attack (TIA) is a prototype of vascular cognitive impairment (VCI). Our recent in vivo study using carbon-11-labeled Pittsburgh compound B ( 11 C-PiB) positron emission tomography (PET) found that ≈30% of subjects with poststroke/TIA cognitive impairment harbored Alzheimer's pathology.1 Although some studies suggested that in patients with clinical Alzheimer's disease (AD), comorbid cerebrovascular disease was associated with a more rapid cognitive decline, 2,3 it is still unknown whether concurrent presence of Alzheimer's pathology is associated with a faster cognitive deterioration in patients with poststroke/TIA cognitive impairment.In this study, we compared the longitudinal cognitive changes between VCI patients with and without AD-like amyloid-beta (Aβ) deposition measured using 11 C-PiB PET. We hypothesized that over 3 years, PiB-positive VCI (mixed VCI [mVCI]) subjects would experience a more rapid and continuous course of cognitive deterioration, resulting in more severe cognitive impairment than those who were PiB-negative (pure VCI [pVCI]). Methods SubjectsSubjects of this study were participants of the ongoing Stroke Registry Investigating cognitive Decline (STRIDE) study. 1 In the Background and Purpose-We hypothesized that comorbid amyloid-beta (Aβ) deposition played a key role in long-term cognitive decline in subjects with stroke/transient ischemic attack. Methods-We recruited 72 subjects with cognitive impairment after stroke/transient ischemic attack to receive Carbon-11-labeled Pittsburgh compound B positron emission tomography. We excluded subjects with known clinical Alzheimer's disease. Those with and without Alzheimer's disease-like Aβ deposition were classified as mixed vascular cognitive impairment (mVCI, n=14) and pure VCI (pVCI, n=58), respectively. We performed Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment to evaluate global cognition and cognitive domains (memory, visuospatial function, language, attention, and executive function) at 3 to 6 months (baseline) and annually for 3 years after the index event. We compared cognitive changes between mVCI and pVCI using linear mixed models and analysis of covariance adjusted for age and education. Results-Over 3 years, there were significant differences between mVCI and pVCI on change of MMSE score over time (group×time interaction, P=0.007). We observed a significant decline on MMSE score (P=0.020) in the mVCI group but not in the pVCI group (P=0.208 6 were performed on subjects at 3 to 6 months (baseline) after the index event to index general cognition. Then subjects were further invited to return for annual follow-up. This study analyzed the data collected ≤3 years.This substudy included a sample of 72 subjects with cognitive impairment (CDR grade ≥0.5) from the STRIDE study. Clinical diagnoses were made by 2 neurologists specialized in dementia (V.C.T.M. and L.A.). Thirty-six subjects had CDR grade of ≥1 and met the criteria for dementia acco...

Severe SVD contributes importantly to delayed-onset dementia after stroke and/or TIA. Future clinical trials aiming to prevent delayed-onset dementia after stroke and/or TIA should target this high-risk group.

We propose a new strip/slot hybrid waveguide with double slots, which exhibits a flat and low dispersion over a 1098-nm bandwidth with four zero-dispersion wavelengths. Dispersion of dual-slot silicon waveguide is mainly determined by mode transition from a strip mode to a slot mode rather than by material dispersion. Dispersion tailoring is investigated by tuning different structural parameters of waveguides. Moreover, nonlinear coefficient of dual-slot silicon waveguide and phase-matching condition in FWM are both explored in detail. The dual-slot waveguide can be used to generate supercontinuum with bandwidth extending up to 1630 nm pumped by femtosecond pulses. This waveguide will have a great potential for ultrabroadband signal processing applications from near-infrared region to mid-infrared region.

Carboxylated cellulose nanocrystals (CNCs-COOH) have attracted great attention for their potential applications in reinforcing polymer materials and surface modification. Herein, we developed a low-cost approach to prepare CNCs-COOH from pulp with high yield at mild reaction conditions (50 °C, 1 wt % sulfuric acid medium) using potassium permanganate (KMnO 4 ) and oxalic acid (OA, H 2 C 2 O 4 ) as the oxidizing and reducing agents, respectively. The oxidant dosage in this strategy is much lower than that in a conventional TEMPO method, and the yield of CNCs-COOH can reach as high as 68.0%, with a carboxylate content of 1.58 mmol/g. In this reaction system, the presence of the OA can complex with Mn 3+ to form [Mn(C 2 O 4 2− )] + and prevent the Mn 3+ from being reduced to Mn 2+ , leading to the strong oxidizing capacity of the reaction system maintained for a longer time. Atomic force microscopy analysis showed that rod-like CNCs were obtained with an average size of 10−22 nm in diameter and 150−300 nm in length. The crystal structure of as-prepared CNCs-COOH was nearly unchanged, and the crystallinity was 89.2% based on WAXD analysis. Of particular interest, CNCs-COOH suspension with high concentration (>6 wt %) also exhibited the same intriguing chiral nematic liquid crystalline self-assembly behaviors as sulfate CNCs prepared by traditional H 2 SO 4 hydrolysis method. This study provides an efficient and cost-effective way to fabricate CNCs-COOH, leading to great potential applications in constructing advanced functional material.

Conventional single cutoff scores are associated with substantially high rates of misclassification especially in older and less-educated patients with stroke. These results caution against the use of one-size-fits-all cutoffs on the MoCA.

ObjectiveWe investigated differences in the anatomical distribution of cerebral microbleeds (CMBs) on MRI, hypothesized to indicate the type of underlying cerebral small vessel disease (SVD), between Eastern and Western general populations.MethodsWe analyzed data from 11 studies identified by a PubMed search between 1996 and April 2014 according to the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data. Study quality measures indicated low or medium risk of bias. We included stroke-free participants from populations aged between 55 and 75 years, categorized by geographic location (Eastern or Western). We categorized CMB distribution (strictly lobar, deep and/or infratentorial [D/I], or mixed [i.e., CMBs located in both lobar and D/I regions]). We tested the hypothesis that Eastern and Western populations have different anatomical distributions of CMBs using multivariable mixed effects logistic regression analyses adjusted for age, sex, and hypertension and clustering by institution.ResultsAmong 8,595 stroke-free individuals (mean age [SD] 66.7 [5.6] years; 48% male; 42% from a Western population), 624 (7.3%) had CMBs (strictly lobar in 3.1%; D/I or mixed in 4.2%). In multivariable mixed effects models, Eastern populations had higher odds of D/I or mixed CMBs (adjusted odds ratio 2.78, 95% confidence interval [CI] 1.77–4.35) compared to Western populations. Eastern populations had a higher number of D/I or mixed CMBs (adjusted prevalence ratio 2.83, 95% CI 1.27–6.31).ConclusionsEastern and Western general populations have different anatomical distributions of CMBs, suggesting differences in the spectrum of predominant underlying SVDs, with potential implications for SVD diagnosis and treatment.