Deformation characteristics of a millimeter-sized thin liquid spherical shell moving at intermediate Reynolds numbers in immiscible liquid are investigated both numerically and experimentally. Experiments are made using the novel principle of sequential production of the shell developed by the authors. Numerical results of the flow pattern around the liquid shell, deformation ratio, and the drag coefficient are compared to experimental results for wide flow conditions. They are in reasonable agreement from the viewpoint of practical engineering. Furthermore, effects of shell deformation on heat transfer characteristics are also investigated numerically. The present research provides the fluid dynamical knowledge for various applications of liquid spherical shells.

Background: Acute cerebral infarction is a rare complication resulting from an unruptured cerebral aneurysm (UCA). There is presently no consensus on the optimal strategy for the management of UCAs with cerebral infarctions. Case Description: A 53-year-old man presented with transient dysarthria and left hemiparesis. Magnetic resonance imaging (MRI) demonstrated the presence of a 7 mm UCA originating from the middle cerebral artery bifurcation, and diffusion-weighted imaging showed no evidence of cerebral infarction. One month later, his transient left hemiparesis recurred, and the patient was admitted to our hospital. Computed tomography angiography showed enlargement of the aneurysm. His left hemiparesis worsened 3 days later. MRI showed cerebral infarction in the area of perforating arteries and further enlargement of the aneurysm with surrounding parenchymal edema. Therefore, the rupture risk was considered to be rarely high and dome clipping was performed immediately. Postoperatively, his neurological status improved without any recurrent brain ischemia. Conclusion: We report a rare case of a rapidly enlarging aneurysm that presented with cerebral infarction. This is the first report describing aneurysmal sac enlargement that can lead to perforating artery obstruction and brain ischemia. The case illustrates the importance of performing close follow-up examinations to confirm findings that suggest a high rupture risk.

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Primary central nervous system lymphoma (PCNSL) is a rare brain tumor that most commonly arises in the cerebral white matter, basal ganglia, peri-ventricle or corpus callosum. Confinement of PCNSL to the third ventricle is extremely rare, and seldom presents with intratumoral hemorrhage (ITH). The present study described the case of a 75-year-old woman who presented with obstructive hydrocephalus due to third-ventricle PCNSL. On magnetic resonance imaging (MRI), the tumor presented ITH on T2*-weighted images and a highly elevated regional cerebral blood volume on dynamic susceptibility contrast-enhanced MRI (DSC-MRI). Due to the high elevation of the regional cerebral blood volume, high-grade glioma was suspected as a preoperative diagnosis. The patient underwent endoscopic tumor biopsy and third ventricle PCNSL was successfully diagnosed. The patient achieved good prognosis at an early stage after the start of treatment initiation. There are many differential considerations for a third-ventricle tumor, and DSC-MRI can help the differential diagnosis of these tumors. Furthermore, the presence of ITH can lead to the inaccurate estimation of regional cerebral blood volume values. Overall, silent or microhemorrhage in PCNSL may be underestimated, and clinicians should therefore carefully evaluate tumor vascularity by MRI.

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