Dielectric and field-induced strain behaviour of (Pb1−xBax) ZrO3 ceramics

The effects of Ba2+ substitution on the dielectric properties and induced strain behaviour of the (Pb1–xBax) ZrO3 ceramics (0.05x0.3) have been investigated as a function of x. A new phase diagram of the (Pb1–xBax) ZrO3 system, indicating the field effect on the phase transition, is also presented. As the Ba2+ content increases, the Curie temperature decreases linearly, whereas maximum dielectric constant increases for up to 20 mol% Ba2+ addition, and then decreases with further Ba2+ addition. Based on the hysteresis loops, the temperature range of the ferroelectric phase as an intermediate phase between the antiferroelectric and paraelectric phases, increases with increasing electric field and Ba2+ content. The ferroelectric loops are induced at room temperature for the specimens containing above 10 mol% Ba2+ by applying an electric field up to 25 kV cm–1. However, for the 5 mol% Ba2+-substituted specimen, no ferroelectric loop is induced, even with applied fields up to 55 kV cm–1. The phase transition due to electric field and Ba2+ addition is also confirmed by the measurement of the field-induced longitudinal strain.     

Mechanical characteristics of fused cast basalt tube encased in steel pipe for protecting steel surface

Because of the various excellent characteristics of cast basalt materials, such as, anti-corrosion, anti-wearing, good hardness, high chemical stability, of which steel may not possess, the steel-basalt composite pipes are used in severe environments for compensating the defects of steel. The limit of bending moment with which steel-basalt composite pipe may safely endure was calculated and the limit curvature of the composite pipe in the safe range was presented. The application temperature of steel-basalt pipe was examined due to a different coefficient among basalt, mortar and mild steel.     

ANALYSIS of BUTTERFAT EXTRACTION and FRACTIONATION USING SUPERCRITICAL CARBON DIOXIDE

A flow through extraction reactor was used to study supercritical fraction-ation of butterfat. the rate of extraction of butterfat was constant for an initial period followed by a decreasing rate of extraction. DSC and GC analyses showed that more soluble triglycerides extracted preferentially in the initial stages exhibited lower melting behavior. the chemical and physical properties of the fractions changed with extraction time. Residual butterfat concentration in the bed was obtained as a function of distance from the bed entrance. the breakthrough curves had a sigmoidal shape, with the ascent-portion of the curves advancing through the bed with the degree of extraction. At the highest extents of extraction, the lower acyl carbon number triglycerides were totally depleted from the lowest portions of the bed, where fresh CO₂ was introduced.     

Effect of Grain Growth on Pore Coalescence During the Liquid-Phase Sintering of MgO-CaMgSiO4 Systems

During the liquid-phase sintering of MgO-CaMgSiO₄ systems in N₂ atmosphere, the total porosity and the average pore size increase while the number of pores decreases. The negligible permeability of entrapped nitrogen through the liquid matrix and the observed linear relationship between the number of pores and that of the MgO grains suggest that the pores coalesce as a consequence of grain growth during sintering. An analysis of the balance between the pressure of the entrapped N₂ gas and the capillary pressure shows that pore coalescence in turn causes the observed porosity increase. When Fe₂O₃ or Cr₂O₃ is added to MgO-CaMgSiO₄, the pore size and the total porosity become larger or smaller, because the grain growth is accelerated or retarded, respectively.     

AKT regulates IL-1β-induced proliferation and activation of hepatic stellate cells

Background: Activated hepatic stellate cells (HSCs) are closely involved in the initiation, perpetuation, and resolution of liver fibrosis. Pro-inflammatory cytokine levels are positively correlated with the transition from liver injury to fibrogenesis and contribute to HSC pathophysiology in liver fibrosis. Methods: In this study, we investigated the effect of the pro-inflammatory cytokine interleukin (IL)-1β on the proliferation and signaling pathways involved in fibrogenesis in LX-2 cells, an HSC cell line, using western blotting and cell proliferation assays. Results: IL-1β increased the proliferation rate and α-smooth muscle actin (SMA) expression of LX-2 cells in a dose-dependent manner. Within 1 h after IL-1β treatment, c-Jun N-terminal kinase (JNK), p38, and nuclear factor-κB (NF-κB) signaling was activated in LX-2 cells. Subsequently, protein kinase B (AKT) phosphorylation and an increase in α- SMA expression were observed in LX-2 cells. Each inhibitor of JNK, p38, or NF-κB decreased cell proliferation, AKT phosphorylation, and α-SMA expression in IL-1β-treated LX-2 cells. Conclusion: These results indicate that JNK, p38, and NF-κB signals converge at AKT phosphorylation, leading to LX-2 activation by IL-1β. Therefore, the AKT signaling pathway can be used as a target for alleviating liver fibrosis by the inflammatory cytokine IL-1β.