Oxidized primary arc magmas: Constraints from Cu/Zr systematics in global arc volcanics.

Arc volcanics are more oxidized than mid-ocean ridge basalts (MORB), but it is debated whether this is a mantle feature or a result of magmatic evolution. Copper, a sulfur-loving element, has been used to trace the behavior of redox-sensitive sulfur during mantle melting and infer similar redox states of sub-arc and sub-ridge mantle. Previous studies, however, neglected elevated sulfur contents in the sub-arc mantle, leading to underestimation of oxygen fugacities, and did not recognize systematic Cu variations in arc volcanics. Here, we show that the Cu/Zr ratio is a sensitive indicator that responds to sulfur content, oxygen fugacity, and extent of melting of the mantle. Because of higher mantle S contents, Cu systematics of arc magmas require one log unit higher oxygen fugacities of sub-arc than sub-ridge mantle. Low Cu contents of thick-crusted arc volcanics result from low extents of melting of sulfur-rich mantle, obviating the need for deep crustal sulfide fractionation, with substantial implications for the origin of porphyry-Cu deposits.

Knockdown of p57 gene inhibits breast cancer cell proliferation.

The aim of the study was to investigate possible effects of p57 on the growth of the human MCF-7 and rat SHZ-88 breast cancer cell lines. Specific oligonucleotide sequences containing small hairpin structure were inserted into a small interfering RNA (siRNA) expression vector. The human MCF-7 and rat SHZ-88 breast cancer cell lines were transfected with recombinant plasmids. The p57 gene expression was blocked in the human MCF-7 breast and rat SHZ-88 breast cancer cells, using chemically modified siRNA. The p57 expression level was evaluated using quantitative polymerase chain reaction (qPCR) and western blot analysis. Immunofluorescence was conducted to detect p57 expression in the breast cancer cells. Tetrazolium blue (MTT) method was employed to detect the effect of p57 inhibition on the proliferation of the MCF-7 and SHZ-88 cell lines. Cell proliferation in the experimental group was significantly reduced. Immunofluorescence assay results showed p57 siRNA effectively inhibited the p57 level in the MCF-7 and SHZ-88 cells. RT-PCR results showed that 48 h after transfection, the p57 mRNA level in the transfected group was significantly lower compared with the control group. In conclusion, p57 effectively inhibited the proliferation of breast cancer after stable interference.

[A high transmittance material in UVc band].

Spectral characteristics of an organic material in acid with different concentrations were investigated in the solution of a proper acid concentration. The results showed that at 252 nm the transmittance T = 56.5%, but at 290 nm the material had a strong absorption peak (epsilon > 10(4) L. (mol.cm)-1). The absorbance A280-298 nm > 8, i.e. T280-298 nm < 10(-8). The band width was about 16 nm. Therefore, this material has conspicuous characteristics such as high transmittance and deep cutoff in the background in ultraviolet-c band. The transmission peak can be shifted in the range of 251-260 nm by changing the pH value of the solution and selecting solution with a different polarity. By analyzing the spectra of the material in acid we found that the two original absorption peaks disappeared, and a new strong absorption peak appeared at 290 nm. Moreover, it seems to be some relation between the two absorption peak intensity and the new peak, which needs to be further studied. Using this result, we can produce high quality UV-filters of this material with traditional coating and colour glass technology.