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Computational Fluid Dynamics (CFD) has become an indispensable tool that can potentially predict many phenomena of practical interest in the tundish. Model verification and validation (V&V) are essential parts of a CFD model development process if the models are to be used with sufficient confidence in real industrial tundish applications. The crucial aspects of CFD simulations in the tundish are addressed in this study, such as the selection of the turbulence models, meshing, boundary conditions, and selection of discretization schemes. A series of CFD benchmarking exercises are presented serving as selected examples of appropriate modelling strategies. A tundish database, initiated by German Steel Institute VDEH working group "Fluid Mechanics and Fluid Simulation", was revisited with the aim of establishing a comprehensive set of best practice guidelines (BPG) in CFD simulations for tundish applications. These CFD benchmark exercises yield important results for the sensible application of CFD models and contribute to further improving the reliability of CFD applications in metallurgical reactors.

Objective: To construct a nanodelivery system surface-modified with RD2 peptide (polypeptide sequence PTLHTHNRRRRR) for brain tissue penetration and β-amyloid (Aβ) binding. Epigallocatechin-3-gallate (EGCG) was selected for encapsulation in the targeted delivery system and its therapeutic potential for Alzheimer's disease (AD) was investigated., Methods: EGCG-load nanoparticles (NP/EGCG), NP/EGCG with RD2 peptide surface modification (RD2-NP/EGCG), as well as RD2 peptide-modified blank nanoparticles (RD2-NP) were prepared and characterized. Thioflavin T assay was done to assess the ability of RD2-NP to bind with Aβ and ex vivo imaging was conducted to evaluate the distribution of RD2-NP in brain lesion sites. The AD mice model was established by injecting oligomeric Aβ 42 in the bilateral hippocampi of ICR mice. Then AD mice were administered intravenously through the tail vein with normal saline, EGCG solution, NP/EGCG or RD2-NP/EGCG for 28 d, respectively, and the Morris water maze tests were performed to assess the spatial memory of mice. Subsequently, RT-PCR method was used to determine the mRNA levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the hippocampus of the mice, and the morphological changes of hippocampal neurons were observed with Nissl staining. Additionally, the pathological changes of heart, liver, spleen, lung, and kidney were characterized by hematoxylin-eosin (HE) staining., Results: The particle diameter of the prepared RD2-NP/EGCG was (204.83±2.80) nm and the zeta potential was -23.88 mV. The encapsulation efficiency and drug loading capacity were 94.39% and 5.90%, respectively. The RD2 peptide modification has no significant effect on the physiochemical properties of the nanoparticles. RD2-NP had good Aβ binding ability, and it could be concentrated in hippocampus and cerebral cortex, the most common Aβ deposition sites. The four-week RD2-NP/EGCG treatment significantly decreased the expression of the pro-inflammatory cytokine TNF-α and IL-1β, restored neuronal losses and hippocampal damage, and ameliorated spatial memory impairment in AD model mice. Moreover, treatment with the RD2-NP/EGCG did not present organ toxicity., Conclusion: Surface modified RD2 peptide nanodelivery system can efficiently deliver drugs to AD lesions and improve the therapeutic effect of EGCG on AD., (Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).)

Natural convection of molten steel flow in a tundish occurs due to the temperature variation of the inlet stream and heat losses through top surface and refractory walls. A computational fluid dynamics (CFD) model was applied to study the effect of thermal buoyancy on fluid flow and residence-time distribution in a single-strand tundish. The CFD model was first validated with the experimental data from a non-isothermal water model and then applied to both scale-down model and prototype. The effects of flow control devices, including weir, dam and turbulence inhibitor, were compared and analyzed. Parameter studies of different heat losses through the top surface were performed. The results show that thermal buoyancy has a significant impact on the flow pattern and temperature distributions of molten steel in the tundish. The increase of heat loss through the top surface shortens the mean residence time of molten steel in the tundish, leading to an increase in dead volume fraction and a decrease in plug flow volume fraction.

The mechanisms driving the spatial patterns of species richness and composition are essential to the understanding of biodiversity. Numerous studies separately identify the contributions of the environment (niche process) and space (neutral process) to the species richness or composition at different scales, but few studies have investigated the contributions of both types of processes in the two types of data at the landscape scale. In this study, we partitioned the spatial variations in all, exotic and native understory plant species richness and composition constrained by environmental variables and space in 134 plots that were spread across 10 counties in Hainan Island in southern China. The 134 plots included 70 rubber (Hevea brasiliensis) plantation plots, 50 eucalyptus (Eucalyptus urophylla) plantation plots, and 14 secondary forest plots. RDA based variation partitioning was run to assess the contribution of environment and space to species richness and composition. The results showed that the environmental variables alone explained a large proportion of the variations in both the species richness and composition of all, native, and exotic species. The RDA results indicated that overstory composition (forest type here) plays a leading role in determining species richness and composition patterns. The alpha and beta diversities of the secondary forest plots were markedly higher than that of the two plantations. In conclusion, niche differentiation processes are the principal mechanisms that shape the alpha and beta diversities of understory plant species in Hainan Island.

The present study investigated whether and how a musical rhythm entrains a listener's visual attention. To this end, participants were presented with pictures of faces and houses and indicated whether picture orientation was upright or inverted. Participants performed this task in silence or with a musical rhythm playing in the background. In the latter condition, pictures could occur off-beat or on a rhythmically implied, silent beat. Pictures presented without the musical rhythm and off-beat were responded to more slowly than pictures presented on-beat. This effect was comparable for faces and houses. Together these results indicate that musical rhythm both synchronizes and facilitates concurrent stimulus processing., (2010 Elsevier B.V. All rights reserved.)

Plasma levels of the renin-angiotensin-aldosterone system (RAAS) and atrial natriuretic peptide (ANP) were studied in healthy male pilots, and in a ground crew control group. Plasma concentrations of angiotensin I (A I), angiotensin II (A II) and aldosterone (Aldo) were measured in the pilots before and after flight by radioimmunoassay. Results showed that the plasma concentrations of A I, A II, and Aldo were much higher after flight than before flight, and were different from samples taken from the control group (p less than 0.001). On the other hand, the ANP levels in the pilot group did not differ significantly from the control group, before or after flight. There was no significant difference of the four hormones within the control group over the course of the study. This suggests that the development of hypertension in pilots may relate to the reaction of the RAAS.