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Numerous studies have examined the associations between air pollution and stroke. However, little is known about the associations between air pollution and transient ischemic attack (TIA). In this study, we aimed to conduct a time-series study to systematically examine the associations between hospital admissions for TIA and air pollutants. Admissions for TIA (ICD-10: G45) from 1 January 2014 to 31 December 2016 were identified based on the primary diagnosis from 134 hospitals in Beijing, China. Hourly measurements of air pollutants were obtained from the National Air Pollution Monitoring System. Generalized additive models with quasi-Poisson regression were used to determine the associations for each pollutant. Additionally, stratified analysis was implemented to examine whether age, gender, temperature, and season were the potential effect modifiers. Restricted cubic spline was applied to investigate the exposure-response curve. In total, 109,975 hospital admissions for TIA were included. The positive associations were detected between PM2.5, PM10, SO2, NO2, and CO and hospital admissions for TIA. The effects of PM2.5 and PM10 in men are stronger than in women. Additionally, the effects of PM2.5, PM10, SO2, and O3 are more pronounced on warm days than cool days. From exposure-response curves, we observe a nearly linear relationship for PM2.5, PM10, CO, and NO2. Further studies are needed to verify the association. This research contributes evidence on the association between air pollution and admissions for TIA in the low- and middle-income countries and may promote related public health policy development.

Aging has a significant effect on the performance of asphalt material. Reliable modelling of the change of asphalt mixture properties over time is crucial to evaluating and predicting the performance of the designed pavement. The objective of this study is to develop an aging model to accurately predict the cracking performance of asphalt mixtures over the pavement service life, as well as evaluate the aging susceptibility of mixtures over time. In this study, nine loose mixtures were conditioned in an oven at 95 °C for multiple durations to simulate different field aging times. The climatic aging index (CAI) developed by the National Cooperative Highway Research Program (NCHRP) 09-54 project was utilized to calculate the appropriate field aging durations corresponding to the different laboratory aging conditions. Complex modulus tests (E*) were conducted to measure the rheological properties of the conditioned mixtures and further construct the dynamic modulus and phase angle mastercurves. The mixture Glover–Rowe (G–Rm) parameter, incorporating both stiffness and relaxation capacity, was selected and used as the Aging Index Property to model the changes in mixture cracking properties with aging. The results of this study indicate that the developed mixture aging model can effectively capture the two aging reaction periods (fast and constant) of asphalt materials. The developed model can not only be used to evaluate the change of cracking properties over pavement service life, but also detect the aging susceptibility of asphalt mixtures.

Background Accumulating evidence has shown that cigarette smoking is an important risk factor for ischemic stroke. However, it is not clear about the potential mechanisms through which cigarette smoking affects stroke risk. In the study, we aimed to investigate the relationship between cigarette smoking and the occurrence of extracranial (ECAS) and intracranial atherosclerotic stenosis (ICAS). Methods We analyzed patients enrolled in the Chinese intracranial atherosclerosis (CICAS), which was a prospective, multicenter, hospital-based cohort study. Smoking status was classified into never, former and current smoking. For those patients with current smoking, data on time duration (year) and extent (the number of cigarette smoked per day) was recorded and pack year of smoking was calculated. ICAS was evaluated with 3-dimentional time-of-flight MRA and ECAS was evaluated with cervical ultrasonography or contrast-enhanced MRA. Multivariable Logistic regression was performed to identify the association between smoking status and the occurrence of ECAS and ICAS. Results A total of 2656 patients (92.7%) of acute ischemic stroke and 208 (7.3%) of transient ischemic attack were analyzed. The mean age was 61.9 ± 11.2 and 67.8% were male. There were 141 (4.9%) patients had only ECAS, 1074 (37.5%) had only ICAS, and 261 (9.1%) had both ECAS and ICAS. Current smoking was significantly associated with the occurrence of ECAS (adjusted OR = 1.47, 95% CI = 1.09–1.99, P