Short-time motion of Brownian particles in a shear flow

The short-time motion of Brownian particles in an incompressible Newtonian fluid under shear, in which the fluid inertia becomes important, was investigated by direct numerical simulation of particulate flows. Three-dimensional simulations were performed, wherein external forces were introduced to approximately form Couette flows throughout the entire system with periodic boundary conditions. In order to examine the validity of the method, the mean square displacement of a single spherical particle in a simple shear flow was calculated, and these results were compared with a hydrodynamic analytical solution that includes the effects of the fluid inertia. Finally, the dynamical behavior of a monodisperse dispersion composed of repulsive spherical particles was examined on short time scales, and the shear-induced diffusion coefficients were measured for several volume fractions up to 0.50

自転−公転ミキサーを用いた人工赤血球（ヘモグロビン ベシクル）の高いカプセル化効率のための調製法

Hemoglobin vesicles (Hb-V) are artificial red blood cells encapsulating highly concentrated hemoglobin (Hb) in liposomes comprising phospholipids, cholesterol, negatively charged lipids, and polyethylene glycol (PEG)-conjugated phospholipids. Safety and efficacy of Hb-V as a transfusion alternative have been extensively studied. For this study, we prepared Hb-V using the kneading method with a rotation-revolution mixer as an alternative to the conventional extrusion method. We optimized the kneading operation parameters to obtain Hb-V with a high yield. Results show that the Hb encapsulation efficiency was increased dramatically up to 74.2%, which is higher than that of the extrusion method (20%) because the kneading method enabled mixing of a highly concentrated carbonylhemoglobin (HbCO) solution (40 g/dL) and a considerably large amount of powdered lipids in only 10 min. The high viscosity of the Hb-lipid mixture paste (ca. 103-105 cP) favorably induces frictional heat by kneading and increases the paste temperature (ca. 60 °C), which facilitates lipid dispersion and liposome formation. During the kneading operation using a thermostable HbCO solution, Hb denaturation was prevented. Hb-V prepared using this method showed no marked changes in particle sizes, Hb denaturation, or Hb leakage from liposomes during two years of long-term storage-stability tests. Collectively, these results demonstrate that the kneading method using a rotation-revolution mixer shows good potential as a new method to produce Hb-V.博士（医学）・甲第797号・令和3年9月29日This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS biomaterials science and engineering, copyright © 2021 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsbiomaterials.1c00424発行元が定める登録猶予期間終了の後、本文を登録予定（2022.06

A direct numerical simulation method for complex modulus of particle dispersions

We report an extension of the smoothed profile method (SPM)[Y. Nakayama, K. Kim, and R. Yamamoto, Eur. Phys. J. E {\bf 26}, 361(2008)], a direct numerical simulation method for calculating the complex modulus of the dispersion of particles, in which we introduce a temporally oscillatory external force into the system. The validity of the method was examined by evaluating the storage $G'(\omega)$ and loss $G"(\omega)$ moduli of a system composed of identical spherical particles dispersed in an incompressible Newtonian host fluid at volume fractions of $\Phi=0$, 0.41, and 0.51. The moduli were evaluated at several frequencies of shear flow; the shear flow used here has a zigzag profile, as is consistent with the usual periodic boundary conditions

Traumatic middle cerebral artery aneurysm: case report and review of the literature

The original publication is available at www.springerlink.comArticleNEUROSURGICAL REVIEW. 30(3): 263-267 (2007)journal articl