Objective To study the chemical composition and the sources of indoor PM10 in some residential houses in Beijing. Methods PM10 samples were collected using cascade impactors in smoker's and non-smoker's homes in winter. The mass concentrations and enrichment characteristics of nineteen elements, such as Al, Si, and S in airborne particles were analyzed by proton induced X-ray emission (PIXE) and enrichment factor. Results The concentrations of 19 elements were higher in smoker's homes than those in non-smoker's homes in winter, especially K and S concentrations were 2-4 times of those in non-smoker's homes. Al, Si, S, K, Ca and Fe made greater contribution to concentrations of elements in PM10, of which K and S accounted for 72% of total elements in smoker's homes while Al, Si and Ca amounted to 57% of total elements in non-smoker's homes. Conclusion Al, Si, Ca, Ti and Fe come from natural sources while S, Zn, Pb, Cr, Cu, As, Cl and P originated from anthropogenic sources such as smoking, coal combustion and oil combustion.

Objective The aim of the study was to investigate the related factor of postoperative provisional paraly?sis of parasagittal meningioma in the eloquent area. Methods A retrospective review was conducted on ninety-six pa?tients with parasagittal meningioma in the eloquent area treated by surgery from May 2005 to December 2015. Accord?ing to the diagnostic criteria for postoperative provisional paralysis, patients were divided into postoperative provisional paralysis group(n=31)and non- postoperative provisional paralysis group(n=65). Univariate and multivariate logistic regression methods were used to analyze the data including age, size of tumor,preoperative epilepsy, preoperative periph?eral edema, complete the occlusion of superior sagittal sinus(SSS) by tumor, incision of SSS during surgery, drainage vein damage during surgery. Results Univariate analysis showed that there were significant differences(P<0.05)between these two groups in age(χ2=14.943,P=0.000), preoperative peripheral edema(χ2=4.435,P=0.049), the complete occlu?sion of SSS by tumor(χ2=5.248,P=0.028), incision of SSS during surgery(χ2=5.773,P=0.026), drainage vein damage during surgery(χ2=11.441,P=0.002). Multivariate analysis showed that the factors related to postoperative provisional paralysis were age(OR=8.709,P=0.028), drainage vein damage during surgery(OR=16.242,P=0.012)and complete oc?clusion of SSS by tumor(OR=0.053,P=0.025). Conclusion Age and the drainage vein damage during surgery are the risk factors of postoperative provisional paralysis and complete occlusion of SSS by tumor is the protective factor for the oc? currence of postoperative provisional paralysis.