ALBERT

Description: 〈p〉Protein function depends critically on intrinsic internal dynamics, which is manifested in distinct ways, such as loop motions that regulate protein recognition and catalysis. Under physiological conditions, dynamic processes occur on a wide range of time scales from subpicoseconds to seconds. Commonly used NMR spin relaxation in solution provides valuable information on very fast and slow motions but is insensitive to the intermediate nanosecond to microsecond range that exceeds the protein tumbling correlation time. Presently, very little is known about the nature and functional role of these motions. It is demonstrated here how transverse spin relaxation becomes exquisitely sensitive to these motions at atomic resolution when studying proteins in the presence of nanoparticles. Application of this novel cross-disciplinary approach reveals large-scale dynamics of loops involved in functionally critical protein-protein interactions and protein-calcium ion recognition that were previously unobservable.〈/p〉

Description: In this paper, high Nb-TiAl alloys with Cr and W additions were prepared by Vacuum induction melting method, and then were heat treated under three different cooling rates of slow cooling, furnace cooling and air cooling. The phase composition of the alloy was analyzed by X ray diffraction, and the microstructure of the alloy was observed by optical microscope (OM), scanning electron microscope (SEM) and energy dispersive analyzer. The results show that the microstructure of Ti45Al8Nb0.2Cr and Ti45Al8Nb0.2W are fully lamellar structure with the main phase composition of α+γ after 3 different heat treatment conditions. The grain size of the two alloys decreases with decreasing of cooling rate, and the grain size of the alloyed with Cr alloy is smaller than that of the alloyed with W alloy. Most of the original massive β phase at grain boundaries and lamellar interfaces dissolved after heat treatment, and the transformation of β phase is easier for Ti45Al8Nb0.2Cr.

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xiang, Limin -- Tao, N J -- England -- Nature. 2016 Mar 3;531(7592):38-9. doi: 10.1038/531038a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Biosensors and Bioelectronics, Biodesign Institute, Arizona State University, Tempe, Arizona 85287, USA. ; State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, China, and at the School of Electrical, Computer and Energy Engineering, Arizona State University.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26935691" target="_blank"〉PubMed〈/a〉

Description: The cotton-like Co(OH) 2 (S-Co(OH) 2 ) was successfully synthesized and its electrochemical performance was systematically investigated. S-Co(OH) 2 was prepared through the “destruction” of the newly formed colloid Co(OH) 2 by the reduction using sodium borohydride. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Used as an anode material for alkaline secondary batteries, S-Co(OH) 2 sample exhibited better cycle stability, higher electrochemical capacity, and higher rate performance than those of conventional β-Co(OH) 2 . At a discharge current density of 100 mA/g, the initial discharge capacity of S-Co(OH) 2 is 549.3 mAh/g and the discharge capacity is still sustained to be 329.2 mAh/g after 100 charge-discharge cycles with a capacity retention of 59.9%.

Description: Using urea as nitrogen source, nitrogen-doped Co-B alloys were prepared by chemical reduction method at different reaction temperatures (25, 50, and 75 °C). The structure and surface morphology were characterized by XRD and SEM. Then they were used as negative electrode materials for alkaline secondary batteries (ASBs). The electrochemical properties were measured by galvanostatic charge-discharge, electrochemical impedance spectroscopy (EIS), and anodic polarization (AP). The experimental results show that the lower the synthesizing temperature is, the better the electrochemical performance of nitrogen-doped Co-B alloy is. For example, nitrogen-doped CoB alloy prepared at 25 °C has an initial discharge capacity of 825.8 mAh/g. After 100 charge/discharge cycles, the discharge specific capacity has remained to be 369.5 mAh/g with capacity retention of 44.7%.

Description: 〈p〉Gastrulation is a key event in embryonic development when the germ layers are specified and the basic animal body plan is established. The complexities of primate gastrulation remain a mystery because of the difficulties in accessing primate embryos at this stage. Here, we report the establishment of an in vitro culture (IVC) system that supports the continuous development of cynomolgus monkey blastocysts beyond early gastrulation up to 20 days after fertilization. The IVC embryos highly recapitulated the key events of in vivo early postimplantation development, including segregation of the epiblast and hypoblast, formation of the amniotic and yolk sac cavities, appearance of the primordial germ cells, and establishment of the anterior-posterior axis. Single-cell RNA-sequencing analyses of the IVC embryos provide information about lineage specification during primate early postimplantation development. This system provides a platform with which to explore the characteristics and mechanisms of early postimplantation embryogenesis in primates with possible conservation of cell movements and lineages in human embryogenesis.〈/p〉

Description: The isotopic compositions of Li and B have great potential for the tracing of fluid sources and for the characterization of ore-forming processes. The fractionation of Li and B isotopes during the magmatic-hydrothermal transition in evolved granites, however, is not well understood as these rocks commonly show multiple late hydrothermal overprints. Tourmaline is sensitive to changes in melt and fluid compositions during its growth and resistant to alteration by later fluids, which makes it a good recorder of Li and B isotopic signatures and fractionation at late evolutionary stages of magmatic systems. To characterize the evolution of a Sn-ore forming granitic intrusion, we analyzed magmatic, hydrothermal, and detrital-sedimentary tourmaline from the Yuanbaoshan granite, associated cassiterite-tourmaline-quartz veins, and disseminated tourmaline-bearing cassiterite-sulfide ore in the sedimentary wall rocks. The Li and B isotopic compositions of tourmaline from these rocks do not covary, largely due to mineral-controlled decoupling during magmatic and hydrothermal processes. Because of the dominant role of tourmaline on the B budget of the rock, magmatic and hydrothermal tourmalines show little variation in δ11B (−12.5 to −8.2‰), a signature reflecting the metasedimentary protoliths of the melt. In contrast, several rock-forming minerals contribute to the budget of Li, which shows significant variation in δ7Li (−0.3 to +6.9‰). The isotopic fractionation of Li in tourmaline from rocks of the Yuanbaoshan area is controlled by three major processes: (i) fractional crystallization results in magmatic tourmaline having progressively higher δ7Li values and higher Li contents, (ii) the magmatic-hydrothermal transition leads to higher δ7Li values at lower Li contents in hydrothermal tourmaline, and (iii) extensive fluid-rock interaction adds isotopically light Li to hydrothermal tourmaline in the wall rocks. Extensive fluid-rock interaction also leached HREE, Mg, isotopically light B, and probably Sn from the granites and/or wall rocks. Tourmaline seems to robustly record progressive changes in Li isotopes in evolving magmatic-hydrothermal systems and hydrothermal mineral deposits.

Description: Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable for several thousand samples, but not practical or scalable for larger, more complex datasets. As results have accumulated, researchers have increasingly gravitated toward larger compilations and statistical tools. New data frameworks have become necessary to handle larger sample sets and encourage more sophisticated or even standardized statistical analyses. In this paper, we describe the Sedimentary Geochemistry and Paleoenvironments Project (SGP; Figure 1), which is an open, community-oriented, database-driven research consortium. The goals of SGP are to (1) create a relational database tailored to the needs of the deep-time (millions to billions of years) sedimentary geochemical research community, including assembling and curating published and associated unpublished data; (2) create a website where data can be retrieved in a flexible way; and (3) build a collaborative consortium where researchers are incentivized to contribute data by giving them priority access and the opportunity to work on exciting questions in group papers. Finally, and more idealistically, the goal was to establish a culture of modern data management and data analysis in sedimentary geochemistry. Relative to many other fields, the main emphasis in our field has been on instrument measurement of sedimentary geochemical data rather than data analysis (compared with fields like ecology, for instance, where the post-experiment ANOVA (analysis of variance) is customary). Thus, the longer-term goal was to build a collaborative environment where geobiologists and geologists can work and learn together to assess changes in geochemical signatures through Earth history. With respect to the data product, SGP is focused on assembling a well-vetted and comprehensive dataset that is tractable to multivariate statistical analyses accounting for multiple geological and methodological biases. Phase 1 of the project, which focused on the Neoproterozoic and Paleozoic, has been completed. Future phases will capture a broader range of geologic time, data types, and geography. The database contains tens of thousands of unpublished data points provided by consortium members, as well as detailed metadata that go beyond what is contained in papers. In many cases, these represent measurements that are tangential to a given published study but still of high utility to database studies; these allow the community to address questions that would be impossible to answer solely with the published data. For instance, in order to use a proxy such as Mo/TOC (total organic carbon) ratios in mudrocks deposited under a euxinic water column, the full suite of trace metal, iron speciation, and total organic carbon data is needed. Likewise, geospatial information is required to account for sampling biases, and many statistical learning approaches cannot accept, or have difficulty with, incomplete geological predictor variables. Ultimately, it is this complete data matrix that will allow for SGP’s most insightful analyses.

Description: There are four episodes (Neoproterozoic, early Paleozoic, early and late Mesozoic) of Sn-W-Nb-Ta mineralization in South China, accounting for more than 50% W and 20% Sn reserves of the world and hosting considerable Nb and Ta resources. The genesis for such large-scale mineralization that may have seen multiple phases of recycling of ore elements is not well unterstood. The study of the earliest mineralized granites in South China, however, may be helpful to better understand the mechanism of mineralization. We present detailed mineralogical, geochemical, and isotopic data from two typical Neoproterozoic, mineralized intrusions, i.e., the Fanjingshan and Yuanbaoshan tourmaline leucogranites. There is a characteritstic mineral succession of diverse magmatic (columbite group minerals [CGMs], Nb-Ta-bearing cassiterite) and hydrothermal (wolframite, wolframoixiolite, Nb-Ta-poor cassiterite) Sn-W-Nb-Ta oxides. Hydrothermal cassiterite and W-bearing oxides (wolframite, wolframoixiolite) in the Yuanbaoshan intrusion were deposited separately by two types, i.e., Sn-rich and Nb-W-rich fluids. In-situ U-Pb dating of zircon, columbite and wolframoixiolite yields ages of 830 ± 5, 832 ± 5 and 821 ± 5 Ma, respectively. Whole-rock εNd(t) values of −2.5 to −6.4 correspond to crustal Nd model ages of 1.6–1.9 Ga. Paleoproterozoic model ages (~1.6–2.2 Ga) for most episodes of W-Nb-Ta mineralization in South China indicate that (i) Paleoproterozoic or older sediments may have been involved in the formation of W-Nb-Ta bearing granites and (ii) contributions of juvenile material was not important for these W-Nb-Ta mineralization. Neoproterozoic peraluminous granites along the Jiangnan Orogen formed in post-collision environments, but only those in the western part show Sn (-W-Nb-Ta) mineralization. The mineralized Neoproterozoic granites of the western part have experienced more extensive fractional crystallization (lower Nb/Ta, Zr/Hf ratios and more depleted in Fe, Mg, Ca, Sr, Ba, Eu, Ti) and are richer in volatiles (H2O, B) than the barren peraluminous intrusions of the eastern part. As similarly evolved Mesozoic metaluminous granites of the Nanling area have considerably more important tin mineralization than the mineralized Neoproterozoic granites, fractionation is not the only factor controlling mineralization. Instead, other factors, such as protolith and conditions of partial melting may account for the more important Mesozoic tin mineralization.