Sex-Related Differences in Clinical Features, Neuroimaging, and Long-Term Prognosis After Transient Ischemic Attack.

BACKGROUND AND PURPOSE: Differences in sex in the incidence, presentation, and outcome of events after ischemic stroke have been studied in depth. In contrast, only limited data are available after transient ischemic attack (TIA). We aim to assess sex-related differences in the presentation, cause, neuroimaging features, and predictors of long-term prognosis in patients with TIA. METHODS: We carried out a prospective cohort study of consecutive patients with TIA from January 2006 to June 2010. Nondefinitive TIA events were defined by the presence of isolated atypical symptoms. The risk of stroke recurrence (SR) and composite of major vascular events were stratified by sex after a median follow-up time of 6.5 (interquartile range, 5.0-9.6) years. RESULTS: Among the 723 patients studied, 302 (41.8%) were female and 79 (10.9%) suffered a nondefinitive TIA event. Vascular territory diffusion-weighted imaging patterns (odds ratio, 1.61 [95% CI, 0.94-2.77]), and nondefinitive TIA events (odds ratio, 2.66 [95% CI, 1.55-4.59]) were associated with women, whereas active smoking (odds ratio, 0.30 [95% CI, 0.15-0.58]) and large artery atherosclerosis causes (odds ratio, 0.50 [95% CI, 0.29-0.83]) were related to men. The risk of SR was similar in both sexes (12.6% [95% CI, 8.9-16.3] for women versus 14.3% [95% CI, 11.0-17.6] for men). In contrast, the risk of major vascular events was significantly lower in women than in men (17.5% [95% CI, 13.2-21.8] versus 23.8% [95% CI, 19.7-27.9]). In both sexes, after adjusting for age, large artery atherosclerosis was associated with SR (hazard ratio, 3.22 [95% CI, 1.42-7.24] and hazard ratio, 2.00 [95% CI, 1.14-3.51]). In a Kaplan-Meier analysis, females with positive diffusion-weighted imaging (P=0.014) and definitive TIA (log-rank test P=0.022) had a significantly higher risk of SR. CONCLUSIONS: Despite similar risks of SR, there were sex-related differences in baseline characteristics, presenting symptoms, patterns of acute ischemic lesions, cause, and outcomes. These findings encourage further research into optimal preventive strategies that take into account these differences.

Laser Engineering Nanocarbon Phases within Diamond for Science and Electronics.

Diamond, as the densest allotrope of carbon, displays a range of exemplary material properties that are attractive from a device perspective. Despite diamond displaying high carbon-carbon bond strength, ultrashort (femtosecond) pulse laser radiation can provide sufficient energy for highly localized internal breakdown of the diamond lattice. The less-dense carbon structures generated on lattice breakdown are subject to significant pressure from the surrounding diamond matrix, leading to highly unusual formation conditions. By tailoring the laser dose delivered to the diamond, it is shown that it is possible to create continuously modified internal tracks with varying electrical conduction properties. In addition to the widely reported conducting tracks, conditions leading to semiconducting and insulating written tracks have been identified. High-resolution transmission electron microscopy (HRTEM) is used to visualize the structural transformations taking place and provide insight into the different conduction regimes. The HRTEM reveals a highly diverse range of nanocarbon structures are generated by the laser irradiation, including many signatures for different so-called diaphite complexes, which have been seen in meteorite samples and seem to mediate the laser-induced breakdown of the diamond. This work offers insight into possible formation methods for the diamond and related nanocarbon phases found in meteorites.

Surface States of (100) O-Terminated Diamond: Towards Other 1 × 1:O Reconstruction Models.

Diamond surface properties show a strong dependence on its chemical termination. Hydrogen-terminated and oxygen-terminated diamonds are the most studied terminations with many applications in the electronic and bioelectronic device field. One of the main techniques for the characterization of diamond surface terminations is X-ray photoelectron spectroscopy (XPS). In this sense, the use of angleresolved XPS (ARXPS) experiments allows obtaining depth-dependent information used here to evidence (100)Oterminated diamond surface atomic configuration when fabricated by acid treatment. The results were used to compare the chemistry changes occurring during the oxidation process using a sublayer XPS intensity model. The formation of nondiamond carbon phases at the subsurface and higher oxygen contents were shown to result from the oxygenation treatment. A new (100) 1 × 1:O surface reconstruction model is proposed to explain the XPS quantification results of Oterminated diamond.