[Construction and Evaluation on Size Resolved Source Apportionment Methods Based on Particle Size Distribution of Chemical Species].

The analysis of the sources of atmospheric particulate pollution can provide scientific support for the prevention and control of air pollution. Most particulate matter (PM) source analysis studies are based on the chemical composition of PM. In addition, particle size characteristics are also one of the important properties of PM. The accuracy of analytical results can be improved by analyzing the particle size characteristics of chemical components. In this study we aim to to solve the problem of insufficient utilization of component particle size information by using a the three-dimensional multi-particle size factor analysis model (ABB), where the particle size distribution of marked components is regarded as the constraint limit, and a multi-particle size source analytical model (SDABB) based on the characteristics of the components particle size distribution is constructed. The sensitivity of the SDABB model to the collinearity of the source spectrum and the similarity of the particle size distribution of the source contributions are investigated by evaluating the model through the simulation of the data set. The results showed that the ABB model was sensitive to the collinearity of the source spectrum and to the similarity of the particle size distribution of the source contributions. When particle size distribution rules were incorporated into the SDABB model, the effects of the two scenarios were significantly improved, that is, the SDABB model was able to better analyze collinear source spectrum and was insensitive to the similarity of the contribution particle size distribution.

Limb-shaking transient ischemic attack responsive to nimodipine: A case report

Limb-shaking transient ischemic attack (TIA), a rare manifestation, is commonly caused by severe stenosis or occlusion of an extracranial internal carotid artery. Such patients are usually treated with surgical revascularization or anti-platelet therapy. We present a 56-year-old woman with 6 months’ episodic attacks starting with mouth skewed to the right and a sensation of ‘weakness’ involving predominantly her left arm, and at times, also involved the left leg. This was immediately followed by rhythmic jerky movements of the left arm and at times, also involved the left leg. Magnetic resonance angiography revealed severe stenosis of M1 segment of the right middle cerebral artery. The patient’s symptoms were signifi cantly improved by treatment with anti-platelet drugs and nimodipine.