Kinetics of Dynamic Polymer Brush Formation

The kinetics of dynamic polymer brush formation, which is driven by interfacial segregation of amphiphilic block copolymers, was investigated by quartz crystal microbalance (QCM) and neutron reflectivity (NR). High speed formation kinetics in the early stage was probed by QCM, and the later stage, where the formation kinetics became relatively slow, was investigated by NR. QCM detected fairly the fast brush formation kinetics on the order of tens of seconds for the copolymers in use. The dynamic polymer brush rapidly grows initially and hence repairs itself when the surface is damaged and the brush is partly lost. This fast dynamic polymer brush formation is driven by relatively slow diffusion of block copolymers in the matrix. The slow diffusion suggests that the diffusion mechanism is not controlled by simple Rouse or reputational diffusion but by the activation hopping mechanism of self-assembled diblock copolymers

Visualization of Resected Area in Endonasal Endoscopic Approach versus Transcranial Approach for Skull Base Meningiomas by Voxel-Based-Lesion Mapping

Background: We aimed to evaluate the resected area of endonasal endoscopic approach (EEA) and transcranial approach (TCA) for skull base meningiomas (SBMs) using voxel-based-lesion mapping and visualized the appropriate tumor location in each approach. Methods: We retrospectively examined 182 patients with SBMs who underwent tumor resection in our hospital between 2014 and 2019. Pre- and post-operative SBMs were manually delineated on MRI to create the voxels-of-interest (VOIpre and VOIpost) and were registered onto the normalized brain (normalized VOIpre and normalized VOIpost). The resected map was created by subtracting normalized VOIpost from the normalized VOIpre divided by the number of cases. The resected maps of TCA and EEA were compared by subtracting them. Results: Twenty patients underwent EEA and 135 patients underwent TCA. The tumor resected map demonstrated that the resected area of EEA frequently accumulated on the central skull base, while that of TCA accumulated near the central skull base. The border of both approaches matched the circle that connects neural foramens at the skull base. Conclusions: The resected area of SBMs by EEA and TCA was well visualized by voxel-based-lesion mapping. The circle connecting the neural foramens was the border of EEA and TCA