Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite

1H, 27Al, 29Si and 39K solid-state NMR are reported from a Hungarian illite 2:1 clay for samples heated up 1600 °C. This single-phase sample has a small amount of aluminium substitution in the silica layer and very low iron-content (0.4 wt%). Thermal analysis shows several events that can be related to features in the NMR spectra, and hence changes in the atomic scale structure. As dehydroxylation occurs there is increasing AlO4 and AlO5-contents. The silica and gibbsite layers become increasingly separated as the dehydroxylation progresses. Between 900 and 1000 °C the silica layer forms a potassium aluminosilicate glass. The gibbsite-layer forms spinel/γ-Al2O3 and some aluminium-rich mullite. Then on heating to 1600 °C changes in the 29Si and 27Al MAS NMR spectra are consistent with the aluminosilicate glass increasing its aluminium-content, the amount of mullite increasing probably with its silicon-content also increasing, and some α-Al2O3 forming

Bcar1/p130Cas protein and primary breast cancer: prognosis and response to tamoxifen treatment

BACKGROUND: The product of the Bcar1/p130Cas (breast cancer resistance/p130Crk-associated substrate) gene causes resistance to antiestrogen drugs in human breast cancer cells in vitro. To investigate its role in clinical breast cancer, we determined the levels of Bcar1/p130Cas protein in a large series of primary breast carcinomas. METHODS: We measured Bcar1/p130Cas protein in cytosol extracts from 937 primary breast carcinomas by western blot analysis. The levels of Bcar1/p130Cas protein were tested for associations and trends against clinicopathologic and patient characteristics, the lengths of relapse-free survival and overall survival (n = 775), and the efficacy of first-line treatment with tamoxifen for recurrent or metastatic disease (n = 268). RESULTS: Bcar1/p130Cas levels in primary tumors were associated with age/menopausal status and the levels of estrogen receptor and progesterone receptor. In univariate survival analysis, higher Bcar1/p130Cas levels were associated with poor relapse-free survival and overall survival (both two-sided P =.04; log-rank test for trend). In multivariate analysis, a high level of Bcar1/p130Cas was independently associated with poor relapse-free survival and overall survival. The response to tamoxifen therapy in patients with recurrent disease was reduced in patients with primary tumors that expressed high levels of Bcar1/p130Cas. In multivariate analysis for response, Bcar1/p130Cas was independent of classical predictive factors, such as estrogen receptor status, age/menopausal status, disease-free interval, and dominant site of relapse. CONCLUSION: Patients with primary breast tumors expressing a high level of Bcar1/p130Cas protein appear to experience more rapid disease recurrence and have a greater risk of (intrinsic) resistance to tamoxifen therapy. Thus, measurement of Bcar1/p130Cas may provide useful prognostic information for patients with primary or metastatic breast cancer

Chemostratigraphy of Neoproterozoic carbonates: implications for 'blind dating'

The delta C-13(carb) and Sr-87/Sr-86 secular variations in Neoproteozoic seawater have been used for the purpose of 'isotope stratigraphy' but there are a number of problems that can preclude its routine use. In particular, it cannot be used with confidence for 'blind dating'. The compilation of isotopic data on carbonate rocks reveals a high level of inconsistency between various carbon isotope age curves constructed for Neoproteozoic seawater, caused by a relatively high frequency of both global and local delta C-13(carb) fluctuations combined with few reliable age determinations. Further complication is caused by the unresolved problem as to whether two or four glaciations, and associated negative delta C-13(carb) excursions, can be reliably documented. Carbon isotope stratigraphy cannot be used alone for geological correlation and 'blind dating'. Strontium isotope stratigraphy is a more reliable and precise tool for stratigraphic correlations and indirect age determinations. Combining strontium and carbon isotope stratigraphy, several discrete ages within the 590-544 Myr interval, and two age-groups at 660-610 and 740-690 Myr can be resolved

Palaeoproterozoic magnesite: lithological and isotopic evidence for playa/sabkha environments

Magnesite forms a series of 1- to 15-m-thick beds within the approximate to2.0 Ga (Palaeoproterozoic) Tulomozerskaya Formation, NW Fennoscandian Shield, Russia. Drillcore material together with natural exposures reveal that the 680-m-thick formation is composed of a stromatolite-dolomite-'red bed' sequence formed in a complex combination of shallow-marine and non-marine, evaporitic environments. Dolomite-collapse breccia, stromatolitic and micritic dolostones and sparry allochemical dolostones are the principal rocks hosting the magnesite beds. All dolomite lithologies are marked by delta C-13 values from +7.1 parts per thousand to +11.6 parts per thousand (V-PDB) and delta O-18 ranging from 17.4 parts per thousand to 26.3 parts per thousand (V-SMOW). Magnesite occurs in different forms: finely laminated micritic; stromatolitic magnesite; and structureless micritic, crystalline and coarsely crystalline magnesite. All varieties exhibit anomalously high delta C-13 values ranging from +9.0 parts per thousand to +11.6 parts per thousand and delta O-18 values of 20.0-25.7 parts per thousand. Laminated and structureless micritic magnesite forms as a secondary phase replacing dolomite during early diagenesis, and replaced dolomite before the major phase of burial. Crystalline and coarsely crystalline magnesite replacing micritic magnesite formed late in the diagenetic/metamorphic history. Magnesite apparently precipitated from sea water-derived brine, diluted by meteoric fluids. Magnesitization was accomplished under evaporitic conditions (sabkha to playa lake environment) proposed to be similar to the Coorong or Lake Walyungup coastal playa magnesite. Magnesite and host dolostones formed in evaporative and partly restricted environments; consequently, extremely high delta C-13 values reflect a combined contribution from both global and local carbon reservoirs. A C- 13-rich global carbon reservoir (delta C-13 at around +5 parts per thousand) is related to the perturbation of the carbon cycle at 2.0 Ga, whereas the local enhancement in C-13 (up to +12 parts per thousand) is associated with evaporative and restricted environments with high bioproductivity

Incorporating New Technologies Into Toxicity Testing and Risk Assessment: Moving From 21st Century Vision to a Data-Driven Framework

Based on existing data and previous work, a series of studies is proposed as a basis toward a pragmatic early step in transforming toxicity testing. These studies were assembled into a data-driven framework that invokes successive tiers of testing with margin of exposure (MOE) as the primary metric. The first tier of the framework integrates data from high-throughput in vitro assays, in vitro-to-in vivo extrapolation (IVIVE) pharmacokinetic modeling, and exposure modeling. The in vitro assays are used to separate chemicals based on their relative selectivity in interacting with biological targets and identify the concentration at which these interactions occur. The IVIVE modeling converts in vitro concentrations into external dose for calculation of the point of departure (POD) and comparisons to human exposure estimates to yield a MOE. The second tier involves short-term in vivo studies, expanded pharmacokinetic evaluations, and refined human exposure estimates. The results from the second tier studies provide more accurate estimates of the POD and the MOE. The third tier contains the traditional animal studies currently used to assess chemical safety. In each tier, the POD for selective chemicals is based primarily on endpoints associated with a proposed mode of action, whereas the POD for nonselective chemicals is based on potential biological perturbation. Based on the MOE, a significant percentage of chemicals evaluated in the first 2 tiers could be eliminated from further testing. The framework provides a risk-based and animal-sparing approach to evaluate chemical safety, drawing broadly from previous experience but incorporating technological advances to increase efficiency

Validation of revised methane and nitrous oxide profiles from MIPAS-ENVISAT

Improved versions of CH4 and N2O profiles derived at the Institute of Meteorology and Climate Research and Instituto de Astrofísica de Andalucía (CSIC) from spectra measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have become available. For the MIPAS full-resolution period (2002-2004) these are V5H-CH4-21 and V5H-N2O-21 and for the reduced-resolution period (2005-2012) these are V5R-CH4-224, V5R-CH4-225, V5R-N2O-224 and V5R-N2O-225. Here, we compare CH4 profiles to those measured by the Fourier Transform Spectrometer on board of the Atmospheric Chemistry Experiment (ACE-FTS), the HALogen Occultation Experiment (HALOE) and the Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY), to the Global Cooperative Air Sampling Network (GCASN) surface data. We find the MIPAS CH4 profiles below 25 km to be typically higher of the order of 0.1 ppmv for both measurement periods. N2O profiles are compared to those measured by ACE-FTS, the Microwave Limb Sounder on board of the Aura satellite (Aura-MLS) and the Sub-millimetre Radiometer on board of the Odin satellite (Odin-SMR) as well as to the Halocarbons and other Atmospheric Trace Species Group (HATS) surface data. The mixing ratios of the satellite instruments agree well with each other for the full-resolution period. For the reduced-resolution period, MIPAS produces similar values as Odin-SMR, but higher values than ACE-FTS and HATS. Below 27 km, the MIPAS profiles show higher mixing ratios than Aura-MLS, and lower values between 27 and 41 km. Cross-comparisons between the two MIPAS measurement periods show that they generally agree quite well, but, especially for CH4, the reduced-resolution period seems to produce slightly higher mixing ratios than the full-resolution data. © Author(s) 2016

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie