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Chronic nerve compression (CNC) induces a permeability change in neural vasculature. As recent evidence has shown that an alteration in reactive oxidative species (ROS) is related to neural degradation and regeneration, we evaluated whether inducible nitric oxide synthase (iNOS) plays a role in a rat model for CNC. Semi-quantitative analysis of iNOS mRNA and protein were performed with in situ hybridization and immunohistochemistry, respectively, at 3, 5, and 9 months post-operatively. At 3 months, iNOS mRNA was up-regulated in the perineurium of the proximal nerve with detectable changes in compressed and distal nerve segments. This expression continued to increase in the perineurium of 5-month proximal and compressed nerve segments with distal nerve demonstrating only a slight up-regulation of iNOS mRNA. At 9 months, iNOS mRNA expression was observed in both compressed and distal nerve. iNOS protein expression followed the same pattern of iNOS mRNA. As the perineurium is the blood-nerve barrier, the data suggests that these changes maybe mediated at the level of the perineurium. As macrophages release iNOS, we also evaluated whether macrophage recruitment followed the same pattern as iNOS expression. The results of ED-1 immunostaining for macrophages indicate that macrophages were localized to the outer one-third of cross sections during early time points. At later time points, macrophages were distributed diffusely throughout the nerve sections. Contrary to Wallerian degeneration, which elicits a relatively immediate signal for macrophage recruitment, CNC provides a slow, sustained stimulus for macrophage recruitment, which may be responsible for the up-regulation of iNOS gene expression.

In this paper, we report a further study of flow-network generating four jet flows which circulate in a sealed device to experimentally investigate the feasibility and efficiency of a dual-axis gyroscope. The experiment is carried out successfully and the experimental results reasonably agreed with those obtained by numerical analysis using OpenFOAM. The flow rectifying coefficient is determined using the mathematical lump model for a vibrating system, which takes into account of the device geometry and resonant frequency. Experimental and numerical results demonstrate that the coefficient of the new system developed in this study is significantly higher than those of conventional designs. The hotwire-integrated device which can function as a dual-axis gyroscope is tested using a turntable with speeds up to 1900 rpm. The scale factor and cross-sensitivity of the system are 0.26 μVs/° and 1.2 %, respectively. The cross-sensitivity and the effects of linear acceleration, actuating voltage on the diaphragm, heating power and position of hotwires are also investigated.

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