Placement sensitivity to aberration in optical imaging

Theories are developed to quantify the shift of image intensity extremum (/spl Delta/x) due to aberration. The theory on real, one-dimensional mask spectrum has been extended to complex, two-dimensional mask spectrum under coherent and partially coherent imaging. Verification of the formulae was performed on alternating phase-shifting mask (PSM) and contact array. Balanced third-order coma was used to illustrate the validity of the theories. It is found that the image shift due to aberration of alternating PSM decreases when the partial coherence factor increases. In general, the theories can be applied to any mask spectra and aberration functions.published_or_final_versio

Association between treatment with apixaban, dabigatran, rivaroxaban, or warfarin and the risk of osteoporotic fractures among patients with atrial fibrillation: A population-based cohort study

Background: It is unclear whether anticoagulant type is associated with the risk for osteoporotic fracture, a deleterious complication of anticoagulants among patients with atrial fibrillation (AF). Objective: To compare the risk for osteoporotic fracture between anticoagulants. Design: Population-based cohort study. Setting: Territory-wide electronic health record database of the Hong Kong Hospital Authority. Participants: Patients newly diagnosed with AF between 2010 and 2017 who received a new prescription for warfarin or a direct oral anticoagulant (DOAC) (apixaban, dabigatran, or rivaroxaban). Follow-up ended on 31 December 2018. Measurements: Osteoporotic hip and vertebral fractures in anticoagulant users were compared using propensity score–weighted cumulative incidence differences (CIDs). Results: There were 23 515 patients identified (3241 apixaban users, 6867 dabigatran users, 3866 rivaroxaban users, and 9541 warfarin users). Overall mean age was 74.4 years (SD, 10.8), ranging from 73.1 years (warfarin) to 77.9 years (apixaban). Over a median follow-up of 423 days, 401 fractures were identified (crude event number [weighted rate per 100 patient-years]: apixaban, 53 [0.82]; dabigatran, 95 [0.76]; rivaroxaban, 57 [0.67]; and warfarin, 196 [1.11]). After 24-month follow-up, DOAC use was associated with a lower risk for fracture than warfarin use (apixaban CID, −0.88% [95% CI, −1.66% to −0.21%]; dabigatran CID, −0.81% [CI, −1.34% to −0.23%]; and rivaroxaban CID, −1.13% [CI, −1.67% to −0.53%]). No differences were seen in all head-to-head comparisons between DOACs at 24 months (apixaban vs. dabigatran CID, −0.06% [CI, −0.69% to 0.49%]; rivaroxaban vs. dabigatran CID, −0.32% [CI, −0.84% to 0.18%]; and rivaroxaban vs. apixaban CID, −0.25% [CI, −0.86% to 0.40%]). Limitation: Residual confounding is possible. Conclusion: Among patients with AF, DOAC use may result in a lower risk for osteoporotic fracture compared with warfarin use. Fracture risk does not seem to be altered by the choice of DOAC. These findings may help inform the benefit–risk assessment when choosing between anticoagulants. Primary Funding Source: The University of Hong Kong and University College London Strategic Partnership Fund

Biophysical Assessment of Single Cell Cytotoxicity: Diesel Exhaust Particle-Treated Human Aortic Endothelial Cells

Exposure to diesel exhaust particles (DEPs), a major source of traffic-related air pollution, has become a serious health concern due to its adverse influences on human health including cardiovascular and respiratory disorders. To elucidate the relationship between biophysical properties (cell topography, cytoskeleton organizations, and cell mechanics) and functions of endothelial cells exposed to DEPs, atomic force microscope (AFM) was applied to analyze the toxic effects of DEPs on a model cell line from human aortic endothelial cells (HAECs). Fluorescence microscopy and flow cytometry were also applied to further explore DEP-induced cytotoxicity in HAECs. Results revealed that DEPs could negatively impair cell viability and alter membrane nanostructures and cytoskeleton components in a dosage- and a time-dependent manner; and analyses suggested that DEPs-induced hyperpolarization in HAECs appeared in a time-dependent manner, implying DEP treatment would lead to vasodilation, which could be supported by down-regulation of cell biophysical properties (e.g., cell elasticity). These findings are consistent with the conclusion that DEP exposure triggers important biochemical and biophysical changes that would negatively impact the pathological development of cardiovascular diseases. For example, DEP intervention would be one cause of vasodilation, which will expand understanding of biophysical aspects associated with DEP cytotoxicity in HAECs

Cerebral microbleeds and stroke risk after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies

BACKGROUND: Cerebral microbleeds are a neuroimaging biomarker of stroke risk. A crucial clinical question is whether cerebral microbleeds indicate patients with recent ischaemic stroke or transient ischaemic attack in whom the rate of future intracranial haemorrhage is likely to exceed that of recurrent ischaemic stroke when treated with antithrombotic drugs. We therefore aimed to establish whether a large burden of cerebral microbleeds or particular anatomical patterns of cerebral microbleeds can identify ischaemic stroke or transient ischaemic attack patients at higher absolute risk of intracranial haemorrhage than ischaemic stroke. METHODS: We did a pooled analysis of individual patient data from cohort studies in adults with recent ischaemic stroke or transient ischaemic attack. Cohorts were eligible for inclusion if they prospectively recruited adult participants with ischaemic stroke or transient ischaemic attack; included at least 50 participants; collected data on stroke events over at least 3 months follow-up; used an appropriate MRI sequence that is sensitive to magnetic susceptibility; and documented the number and anatomical distribution of cerebral microbleeds reliably using consensus criteria and validated scales. Our prespecified primary outcomes were a composite of any symptomatic intracranial haemorrhage or ischaemic stroke, symptomatic intracranial haemorrhage, and symptomatic ischaemic stroke. We registered this study with the PROSPERO international prospective register of systematic reviews, number CRD42016036602. FINDINGS: Between Jan 1, 1996, and Dec 1, 2018, we identified 344 studies. After exclusions for ineligibility or declined requests for inclusion, 20 322 patients from 38 cohorts (over 35 225 patient-years of follow-up; median 1·34 years [IQR 0·19-2·44]) were included in our analyses. The adjusted hazard ratio [aHR] comparing patients with cerebral microbleeds to those without was 1·35 (95% CI 1·20-1·50) for the composite outcome of intracranial haemorrhage and ischaemic stroke; 2·45 (1·82-3·29) for intracranial haemorrhage and 1·23 (1·08-1·40) for ischaemic stroke. The aHR increased with increasing cerebral microbleed burden for intracranial haemorrhage but this effect was less marked for ischaemic stroke (for five or more cerebral microbleeds, aHR 4·55 [95% CI 3·08-6·72] for intracranial haemorrhage vs 1·47 [1·19-1·80] for ischaemic stroke; for ten or more cerebral microbleeds, aHR 5·52 [3·36-9·05] vs 1·43 [1·07-1·91]; and for ≥20 cerebral microbleeds, aHR 8·61 [4·69-15·81] vs 1·86 [1·23-1·82]). However, irrespective of cerebral microbleed anatomical distribution or burden, the rate of ischaemic stroke exceeded that of intracranial haemorrhage (for ten or more cerebral microbleeds, 64 ischaemic strokes [95% CI 48-84] per 1000 patient-years vs 27 intracranial haemorrhages [17-41] per 1000 patient-years; and for ≥20 cerebral microbleeds, 73 ischaemic strokes [46-108] per 1000 patient-years vs 39 intracranial haemorrhages [21-67] per 1000 patient-years). INTERPRETATION: In patients with recent ischaemic stroke or transient ischaemic attack, cerebral microbleeds are associated with a greater relative hazard (aHR) for subsequent intracranial haemorrhage than for ischaemic stroke, but the absolute risk of ischaemic stroke is higher than that of intracranial haemorrhage, regardless of cerebral microbleed presence, antomical distribution, or burden

Deep etch of GaN by laser micromachining

Trench formation for device isolation on GaN lightemitting diode (LED) wafers via nanosecond ultraviolet laser micromachining is demonstrated. Owing to the dissimilar ablation thresholds between GaN and sapphire, the etch process terminates automatically at the GaN/sapphire interface. It was found that optimal focus offset, optimal pulse energy and high repetition rate are essential for obtaining a trench with tapered sidewall and smooth bottom surface, which is suitable for the conformal deposition of interconnects across the trench. This technique has been successfully applied to the rapid prototyping of interconnected LED arrays on a single chip. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.link_to_subscribed_fulltextThe 8th International Conference on Nitride Semiconductors (ICNS), Jeju, Korea, 18-23 October 2009

Effect of prenatal maternal depression on early speech sound acquisition: a preliminary study

OBJECTIVE: Speech sound disorders (SSD) are the most prevalent childhood communication disorders. Many cases of SSD have an unknown origin. The study investigated the effect of prenatal maternal depression on the offspring's speech sound production. METHOD: Data from 26 mother–child dyads were included in the study. Prenatal maternal depression was assessed by a validated questionnaire during the third trimester of pregnancy. Speech sound production ability was assessed in terms of the number of atypical (non-developmental) speech errors produced in a standardized speech assessment when the children were 2-years-old. RESULTS: Six of the mothers’ questionnaires suggested depression, whereas 20 were within normal limits. Hierarchical multiple regression analyses indicated that prenatal depression uniquely accounted for 30.8% of the variance in speech sound acquisition after controlling for the child's sex and postnatal maternal depression level. CONCLUSIONS: Maternal prenatal depression was significantly associated with more atypical speech errors in the offspring at 2 years. The current findings contribute to understanding the etiology of SSD with unknown origin. At a clinical level, prenatal depression could be taken as a risk factor for SSD