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Abstract: A series of silica particles with different size and surface groups were prepared through the sol–gel process of tetraethylorthosilicate, then directly introduced into polyester polyol resins via in situ (IS) polymerization or blending (BL) method and investigated by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), viscosity measurement, particle size analyzer and transmittance electron microscope (TEM), respectively. The results showed that polyester segments were chemically bonded onto silica particles for both IS and BL methods, but more polyester segments chemically bonded onto the surfaces of silica particles during IS polymerization than those during BL process, resulting in lower viscosity of nanocomposite resins from IS polymerization than their corresponding resins from BL method. TEM indicated that silica particles could be dispersed into polymer resins during IS polymerization while causing obvious aggregation during BL method. [Copyright &y& Elsevier]

Mirror intracranial aneurysms with different rupture status is a useful model to investigate features associated with aneurysm rupture. Morphological and hemodynamic analyses of ruptured middle cerebral artery (MCA) mirror aneurysms are rarely reported. The purpose of this study was to determine the morphological or hemodynamic characteristics associated with ruptured MCA mirror aneurysms. We performed a retrospective analysis of consecutive 317 patients with MCA aneurysms. Ruptured MCA mirror aneurysms (1 ruptured and mirror unruptured aneurysm) were included. In the matched pairs of ruptured and unruptured mirror aneurysms, 13 morphological parameters were measured using 3-dimensional computed tomography angiography and 6 hemodynamic parameters were evaluated using high-resolution computational fluid dynamic simulations. The association of morphological and hemodynamic characteristics with the rupture of MCA mirror aneurysms was determined. A total of 20 (6.31%) patients with 40 MCA mirror aneurysms were included in this study. There were significant differences in morphological and hemodynamic parameters between the ruptured and unruptured mirror aneurysms. Irregular aneurysms were 3 times more common in the ruptured aneurysms than in the unruptured aneurysms. A larger aneurysm (P = 0.025), a higher aneurysm (P = 0.020), a larger size ratio (P = 0.009), a higher bottleneck ratio (P = 0.033), an irregular aneurysm (P = 0.022), a higher maximum intra-aneurysmal wall shear stress (WSS; P = 0.020), and a lower normalized average WSS (P = 0.008) were associated with MCA mirror aneurysm rupture. Larger aneurysms, a larger size ratio, irregular aneurysms, a lower spatial average WSS, and a higher maximum WSS may contribute to evaluating the risk of rupture of MCA aneurysms independent of patient characteristics. [ABSTRACT FROM AUTHOR]