Flow-induced vibration in the compressible cavity flow

The cavity plays an important role in the fuel-air mixing and combustion stability inside the hypersonic scramjet. However, the high levels of time-dependent loading resulting from the supersonic cavity flow can cause intense structural vibration even damage. Experiments and numerical simulations were performed to understand the complex fluid-structure interaction in this paper. A cantilever plate with a cavity was installed as a splitter plate in the supersonic mixing layer wind tunnel. The response displacements of this cantilever plate were measured by a non-intrusive laser vibrometer. Large eddy simulation (LES) was applied to calculate the aerodynamic loading. Results show that the St number of time-dependent surface-averaged pressure difference agrees well with semi-empirical relation of Heller used to predict the resonance mode. The cantilever plate exhibits a directly dependent response to self-oscillation of supersonic cavity flow. Measurement results of displacement indicate that the vibration shape of this plate is dominantly two-dimensional

Optimal treatment determination on the basis of haematoma volume and intra-cerebral haemorrhage score in patients with hypertensive putaminal haemorrhages: a retrospective analysis of 310 patients

BACKGROUND: Hypertensive putaminal haemorrhage comprises major part of intra-cerebral haemorrhages, with particularly high morbidity and mortality. However, the optimal treatments for these individuals remain controversial. METHODS: From June 2010 to August 2013, patients with hypertensive putaminal haemorrhages were treated in the Department of Neurosurgery, West China Hospital. Information regarding the age, signs of cerebral herniation, haematoma volume, intra-ventricular haemorrhage, intra-cerebral haemorrhage score and the treatments of each patient were analyzed retrospectively. The outcome was evaluated by the 30-day mortality rate. RESULTS: The 30-day mortality rate of the patients with haematomas volume greater than or equal to 30 ml and intra-cerebral haemorrhage scores of 1 or 2 was decreased in the surgical group compared with those in the conservative group (1.92% VS. 21.40%, OR = 0.072, p = 0.028; 15.40% VS. 33.3%, OR = 0.365, p = 0.248, respectively). The mortality rate of the patients with signs of cerebral herniation was not significantly different between the surgical and conservative groups (83.30% VS. 100%; p = 0.529). The intra-cerebral haemorrhage score was significantly associated with the 30-day mortality rate of patients with intra-cerebral haemorrhages (r = -0.798, p < 0.001). CONCLUSION: Patients with basal ganglia haematomas volume greater than or equal to 30 ml and intra-cerebral haemorrhage scores of 1 or 2 could benefit from the surgical removal of haematomas. The intra-cerebral haemorrhage score can accurately predict the 30-day mortality rate of patients with hypertensive putaminal haemorrhages

Compilation of a regionally-extended inter-country input-output table and its application to global value chain analysis

Studies on the rise of global value chains (GVCs) have attracted a great deal of interest in the recent economics literature. However, due to statistical and methodological challenges, most existing research ignores domestic regional heterogeneity in assessing the impact of joining GVCs. GVCs are supported not only directly by domestic regions that export goods and services to the world market, but also indirectly by other domestic regions that provide parts, components, and intermediate services to final exporting regions. To better understand the nature of a country\u27s position and degree of participation in GVCs, we need to fully examine the role of individual domestic regions. Understanding the domestic components of GVCs is especially important for larger economies such as China, the US, India and Japan, where there may be large variations in economic scale, geography of manufacturing, and development stages at the domestic regional level. This paper proposes a new framework for measuring domestic linkages to global value chains. This framework measures domestic linkages by endogenously embedding a target country\u27s (e.g. China and Japan) domestic interregional input–output tables into the OECD inter-country input–output model. Using this framework, we can more clearly understand how global production is fragmented and extended internationally and domestically

Controlled release of chitosan/heparin nanoparticle-delivered VEGF enhances regeneration of decellularized tissue-engineered scaffolds

Regeneration deficiency is one of the main obstacles limiting the effectiveness of tissue-engineered scaffolds. To develop scaffolds that are capable of accelerating regeneration, we created a heparin/chitosan nanoparticle-immobilized decellularized bovine jugular vein scaffold to increase the loading capacity and allow for controlled release of vascular endothelial growth factor (VEGF). The vascularization of the scaffold was evaluated in vitro and in vivo. The functional nanoparticles were prepared by physical self-assembly with a diameter of 67–132 nm, positive charge, and a zeta potential of ∼30 mV and then the nanoparticles were successfully immobilized to the nanofibers of scaffolds by ethylcarbodiimide hydrochloride/hydroxysulfosuccinimide modification. The scaffolds immobilized with heparin/chitosan nanoparticles exhibited highly effective localization and sustained release of VEGF for several weeks in vitro. This modified scaffold significantly stimulated endothelial cells’ proliferation in vitro. Importantly, utilization of heparin/chitosan nanoparticles to localize VEGF significantly increased fibroblast infiltration, extracellular matrix production, and accelerated vascularization in mouse subcutaneous implantation model in vivo. This study provided a novel and promising system for accelerated regeneration of tissue-engineering scaffolds