Geochemical characteristics of biogenic barium in sediments of the Antarctica Ross Sea and their indication for paleoproductivity

241-248In this paper, the biogenic Ba of Column R11 in the Antarctic Ross Sea and its implications to the paleo oceanographic productivity since the late of Late Quaternary were discussed, combined with the organic carbon, opal and biogenic calcium carbonate. The biogenic Ba contents ranged from 51.8 to 508.4 μg/g overall, exhibiting a gradually rising trend from the bottom to the top. It highly correlated both with TOC and opal, revealing that on one hand biogenic Ba can be used to study the change of productivity in the Ross Sea; and on the other hand, the marine productivity gradually increased since the late Pleistocene. The new productivity based on Francois model varied from 0.40 to 233.90 gC/(m2•a). The high values were mainly concentrated at the depth from 32 to 48 cm, but the new productivity values of the bottom were lower. It was inferred that the change in marine productivity in the Ross Sea was possibly affected by the ice cover since the late Pleistocene

{μ-6,6′-Dimeth­oxy-2,2′-[propane-1,3-diylbis(nitrilo­methyl­idyne)]­diphenolato}­trinitratocopper(II)lutetium(III) acetone solvate

In the title complex, [CuLu(C19H20N2O4)(NO3)3]·CH3COCH3, the CuII ion is four-coordinated in a square-planar geometry by two O atoms and two N atoms from the deprotonated Schiff base. The LuIII ion is ten-coordinate, chelated by three nitrate groups and linked to the four O atoms of the deprotonated Schiff base. A mol­ecule of acetone is present as a solvate

Site-specific selection reveals selective constraints and functionality of tumor somatic mtDNA mutations.

BACKGROUND: Previous studies have indicated that tumor mitochondrial DNA (mtDNA) mutations are primarily shaped by relaxed negative selection, which is contradictory to the critical roles of mtDNA mutations in tumorigenesis. Therefore, we hypothesized that site-specific selection may influence tumor mtDNA mutations. METHODS: To test our hypothesis, we developed the largest collection of tumor mtDNA mutations to date and evaluated how natural selection shaped mtDNA mutation patterns. RESULTS: Our data demonstrated that both positive and negative selections acted on specific positions or functional units of tumor mtDNAs, although the landscape of these mutations was consistent with the relaxation of negative selection. In particular, mutation rate (mutation number in a region/region bp length) in complex V and tRNA coding regions, especially in ATP8 within complex V and in loop and variable regions within tRNA, were significantly lower than those in other regions. While the mutation rate of most codons and amino acids were consistent with the expectation under neutrality, several codons and amino acids had significantly different rates. Moreover, the mutations under selection were enriched for changes that are predicted to be deleterious, further supporting the evolutionary constraints on these regions. CONCLUSION: These results indicate the existence of site-specific selection and imply the important role of the mtDNA mutations at some specific sites in tumor development

Expression of an engineered tandem-repeat starch-binding domain in sweet potato plants

In this study, the transgenic sweet potato Xu55-2 modified with an engineered tandem repeat of a family 20 starch binding domain (SBD2) was analyzed by Western dot blot to investigate whether SBD2 proteins are capable of granule-targeting during starch biosynthesis. Furthermore, the impact of SBD2 accumulation in granules on the physicochemical properties of the transgenic starches was also investigated. Our results demonstrate that the high levels of SBD2 protein could be accumulated in granules. The SBD2 expression affect granule morphology without altering the primary structure of the constituent starch molecules, suggesting that SBD2 could be used as an anchor for effector proteins to sweet potato starch granules during biosynthesis.Keywords: Sweet potato (Ipomoea batatas), tandem starch-binding domain, transgenic starch, granule morphology.African Journal of Biotechnology Vol. 12(41), pp. 5994-599

Application of Machine Learning in Financial Asset Pricing:A Review

The key problem of financial asset allocation is asset price.Asset pricing is the core content of modern finance,which indicates that asset pricing law has always been one of the hot topics of financial research.This paper reviews the methods used by machine learning in the field of asset pricing and research progresses,classifies machine learning asset pricing method into machine learning method based on the characteristics processing and deep learning method based on end-to-end processing,compares the differences between different algorithms in principle and application scenarios,points out the applicability and limitations of the two kinds of machine learning methods,prospects the research direction on machine learning asset pricing in the future

Localized States and Quantum Spin Hall Effect in Si-Doped InAs/GaSb Quantum Wells

We study localized in-gap states and quantum spin Hall effect in Si-doped InAs/GaSb quantum wells. We propose a model describing donor and/or acceptor impurities to describe Si dopants. This model shows in-gap bound states and wide conductance plateau with the quantized value $2e^2/h$ in light dopant concentration, consistent with recent experiments by Du et al. We predict a conductance dip structure due to backward scattering in the region where the localization length $\xi$ is comparable with the sample width $L_y$ but much smaller than the sample length $L_x$.Comment: 4+pages main text including 4 figures, supplementary materials with 3 figures are include