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The hydrophilic bile salt ursodeoxycholic acid (UDCA) is a potent inhibitor of apoptosis. In this paper, we further characterize the mechanism by which UDCA inhibits apoptosis induced by deoxycholic acid, okadaic acid and transforming growth factor β1 in primary rat hepatocytes. Our data indicate that coincubation of cells with UDCA and each of the apoptosis-inducing agents was associated with an approximately 80% inhibition of nuclear fragmentation (P<0.001). Moreover, UDCA prevented mitochondrial release of cytochrome c into the cytoplasm by 70-75% (P<0.001), thereby, inhibiting subsequent activation of DEVD-specific caspases and cleavage of poly(ADP-ribose) polymerase. Each of the apoptosis-inducing agents decreased mitochondrial transmembrane potential and increased mitochondrial-associated Bax protein levels. Coincubation with UDCA was associated with significant inhibition of these mitochondrial membrane alterations. The results suggest that the mechanism by which UDCA inhibits apoptosis involves an interplay of events in which both depolarization and channel-forming activity of the mitochondrial membrane are inhibited. [ABSTRACT FROM AUTHOR]

The tailings pond is a dangerous source of man-made debris flow with high potential energy. The oxidative acidification of tailings may cause the instability of the pond and induce serious safety accidents. The influence of oxidation and acidification degree on macro mechanical properties of tailings is discussed from the aspects of mineral composition and microstructure. The results show that as the degree of oxidation and acidification of tailings sand increases, the overall structural performance and load-bearing capacity decrease, and its cohesion (c) and internal friction angle (φ) show a decreasing trend. In fact, the engineering properties of tailings with different oxidation and acidification degrees are dominated by the physicochemical composition and structural characteristics. On the one hand, as the degree of oxidation increases, acidic substance will neutralize with CaCO3 and CaMg(CO3)2, resulting in the loss of cemented substance and the decrease of cementation force between tailing sand particles as well as the gradual destruction of the integrity of tailing sand. On the other hand, the increase of oxidation and acidification degree of tailing sand leads to a gradual reduction of outline (2D) fractal dimension and gray surface (3D) fractal dimension of surface laminated structure as well as the obvious reduction of laminated structure and its roughness of tailings sand. [ABSTRACT FROM AUTHOR]

The "cyborg cells", living cells with built-in nanoscaffolds, which could integrate the biological function of the cells with the functionality of nanomaterials, have been rarely explored. Here we report a method to construct "cyborg erythrocytes" through the in situ reaction of exogenous calcium and carbonate ions to generate calcium carbonate nanodots inside erythrocytes. The intracellular calcium carbonate nanodots combined with proteins are hidden under the membrane of erythrocytes, which can restrict migration and unexpected accumulation of nanodots in the body, improving the biosecurity of the nanodots. Most importantly, the calcium carbonate nanodots not only do not bring adverse effects on the nature of erythrocytes, but also endow erythrocytes with new properties. The in vitro and in vivo results show that the "cyborg erythrocytes" can remove 80% of lead ions in a blood poisoning model and reduce the lead level in the kidney and liver of mice through a precipitation transformation mechanism. Precipitation of inorganic materials on cell surfaces is well established but intracellular nanoparticle synthesis is less common. Here the crystallisation of calcium carbonate from exogenous ions within red blood cells is shown to selectively sequester Pb(II) from blood and to reduce accumulation of Pb(II) in mouse kidney and liver tissue. [ABSTRACT FROM AUTHOR]

In this work, 3,3′,5,5′-tetramethylbenzidine(II) (TMB2+), derived from H2O2-horseradish peroxidase (HRP)-3,3′,5,5′-tetramethylbenzidine (H2O2-HRP-TMB) reaction system, was used to etch AuNRs to generate different colors of solution. Many enzyme reactions are involved in the production of H2O2 (e.g., glucose can react with the dissolved oxygen in the presence of glucose oxidase (GOx) to produce H2O2). Given this information, a simple visual biosensor was developed in this study, with glucose as the example target. The detection range of the proposed system varied with the experimental conditions, such as the concentration of GOx and HRP, and enzymatic reaction time. Under the optimized conditions, the longitudinal shift of localized surface plasmon resonances (LSPR) had a linear correlation with the glucose concentration in the range of 0.1~1.0 mM. Meanwhile, the solution displayed a specific color in response to the glucose concentration, thus enabling the visual quantitative detection of glucose at a glance. Compared with the traditional monochromic colorimetry, this multicolor glucose sensor generates various vivid colors, which can be easily distinguished by naked eyes without any sophisticated instrument. Notably, the proposed method has been successfully applied to detect glucose in serum samples with satisfied results. [ABSTRACT FROM AUTHOR]