RESUMO
Background and purpose: The efficacy and safety of endovascular treatment (EVT) in acute basilar artery occlusion (ABAO) has been confirmed by four randomized clinical trials. Nevertheless, the predictors of a 90-day favorable outcome after EVT have not been elucidated. We attempted to establish a nomogram for the prediction of a 90-day favorable outcome in ABAO patients with EVT. Methods: Clinical data of ABAO patients with EVT were obtained from two nationwide clinical trial registries in China. Factors associated with a 90-day favorable outcome were screened by multivariable step-wise regression on the basis of univariable analysis. A nomogram was established to predict 90-day favorable outcome after EVT. Results: The proportion of ABAO patients with a favorable outcome was 41.53% (157/378). Seven variables, including baseline National Institutes of Health Stroke Scale (NIHSS) <20 [odds ratio (OR): 8.330; P-value < 0.0001], posterior circulation Alberta Stroke Program Early CT (pc-ASPECT) score ≥7 (OR: 1.948; P-value = 0.0296), Pons-Midbrain Index (PMI) score < 2 (OR: 2.108; P-value = 0.0128), Posterior Circulation Collateral Score (PC-CS) ≥5 (OR: 3.288; P-value < 0.0001), local anesthesia (OR: 0.389; P-value = 0.0017), time from onset to recanalization (OTR) <330 min (OR: 2.594; P-value = 0.0013), and no occurrence of early neurological deterioration (END; OR: 0.039; P-value < 0.0001) were included into the nomogram, with C-index values of 0.8730 and 0.8857 in the training and the internal validation set, respectively. Conclusions: The proposed nomogram provided a reliable prognostic scale, which can be employed in clinical settings for the selection and clinical management of ABAO patients. Registration: https://www.clinicaltrials.gov, identifier: NCT03370939.
RESUMO
Silicon carbide (SiC) ceramics have been widely used for microelectronics, aerospace, and other industrial fields due to their excellent chemical stability and thermal tolerance. However, hard machinability and low machining precision of SiC ceramics are the key limitations for their further applications. To address this issue, a novel method of underwater femtosecond laser machining was introduced in this study to obtain high precision and smooth surface of the microgrooves of SiC ceramics. The removal profiles were characterized in terms of width, depth, and surface morphology, which exhibited high dependence on the femtosecond laser processing parameters. The instability during the underwater processing affected by laser-induced gas bubbles and material deposition, however, limits the high surface accuracy of microgrooves and processing efficiency. The process condition transformation from a bubble-disturbed circumstance to a disturbance-free model was carefully investigated through a high speed camera for the femtosecond laser processing of SiC ceramics in water. The experiment results indicated that degree of disturbed effect was heavily dependent on size, distribution, and motion of laser-induced gas bubble. Furthermore, some typical evolution mechanisms of gas bubble and their influence on the removal profiles of microgrooves were discussed in detail. Bubble evolution has been proven to be mainly responsible for the behavior of laser propagation (focus model, total reflection, etc.), which notably affects microstructural characteristic of the microgrooves.
