Mesoporous (ZnO)(x)(MgO)(1-x) nanoplates: template-free solvothermal synthesis, optical properties, and their applications in water treatment

Mesoporous (ZnO)x(MgO)1-x nanoplates were synthesized from a solution containing zinc acetate and magnesium acetate by a template-free solvothermal synthetic method followed by subsequent calcination. After thermal treatment, the plate-like morphology was retained. The formation of pores was due to thermal decomposition of Mg(OH)2 and the release of H2O. The optical properties of the mesoporous (ZnO)x(MgO)1-x nanoplates had been investigated by UV-vis absorption and cathodoluminescence (CL) emission spectroscopy. The UV-vis absorption spectra showed the band gap variation of the as-prepared samples due to the presence of ZnO in the MgO nanostructures. The CL spectra showed strong broad peaks in the visible range from 450 to 700 nm, indicating significant oxygen vacancy defects on the surface of the (ZnO)x(MgO)1-x nanoplates. Moreover, the samples were evaluated as photocatalysts for the UV-induced degradation of methyl orange (MO) in aqueous solution. The (ZnO)x(MgO)1-x nanoplates showed high photocatalytic performance and thus would be promising candidates for polluted water treatment.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Physical activity for children in special school environment

1. We assessed children's physical activity (PA) in structured (physical education) and unstructured (recess, lunch, before and after school) periods in special schools and examined its association with modifiable area contextual characteristics. 2. Children with disabilities were not highly active, but were more active during recess and lunch periods than at other times including physical education classes. 3. Areas were often not accessible during unstructured settings. Children were more active in areas when supervision and organised activities were provided. 4. Providing an interactive game during free play did not significantly increase group's PA. 5. Children's PA accrual is influenced by contextual characteristics of the school environment. There is a need to make areas more accessible and to use social marketing and programming to attract more users. School and health professionals should modify contextual characteristics by providing more direct supervision and organised activities during free play.

The novel BH-3 mimetic apogossypolone induces Beclin-1- and ROS-mediated autophagy in human hepatocellular carcinoma [corrected] cells

Apogossypolone (ApoG2), a novel derivative of gossypol, exhibits superior antitumor activity in Bcl-2 transgenic mice, and induces autophagy in several cancer cells. However, the detailed mechanisms are not well known. In the present study, we showed that ApoG2 induced autophagy through Beclin-1- and reactive oxygen species (ROS)-dependent manners in human hepatocellular carcinoma (HCC) cells. Incubating the HCC cell with ApoG2 abrogated the interaction of Beclin-1 and Bcl-2/xL, stimulated ROS generation, increased phosphorylation of ERK and JNK, and HMGB1 translocation from the nucleus to cytoplasm while suppressing mTOR. Moreover, inhibition of the ROS-mediated autophagy by antioxidant N-acetyl-cysteine (NAC) potentiates ApoG2-induced apoptosis and cell killing. Our results show that ApoG2 induced protective autophagy in HCC cells, partly due to ROS generation, suggesting that antioxidant may serve as a potential chemosensitizer to enhance cancer cell death through blocking ApoG2-stimulated autophagy. Our novel insights may facilitate the rational design of clinical trials for Bcl-2-targeted cancer therapy.