Small-volume Lu-Hf and U-Pb isotope determination of complex zircons by solution and laser ablation MC-ICP-MS

This study presents solution and laser ablation analysis methods suited to the determination of the Lu-Hf and U-Pb isotope signatures of small volumes of zircon corresponding to sub-nanogram amounts of Hf. A reduced-volume approach to laser ablation is taken with consecutive U-Pb and Lu-Hf isotopic analyses resulting in a total pit depth of 18 μm using a 25 μm laser ablation spot. This results in excavation of ~ 40 ng of zircon, equating to ~ 0.3 ng of Hf and uncertainties ~ 1 εHf (2s). The laser technique presented here is ideally suited to complex, finely-zoned zircons for which drilling to depth would intersect different zones. The possibility of reducing the total laser ablation pit depth to ~ 10 μm is demonstrated by decreasing the integration time for Hf isotope analysis without serious compromise of the uncertainty. Furthermore, the capability to determine the Hf isotope composition of the same amount of Hf using solution MC-ICP-MS is also demonstrated, as is the suitability of analyzing solutions not subject to Hf-HREE separation. For both solution and laser ablation methods, this study investigates possible methods of Yb interference correction, the potential for matrix effects, and the accurate determination of 176Lu/177Hf. Using the approaches described here, acceptable uncertainty levels are achieved to resolve complexity at the level of 25 × 18 μm (diameter × depth), and therefore this method has the potential to yield geologically meaningful results for rocks containing complexly-zoned zircons

Deciphering petrogenic processes using Pb isotope ratios from time-series samples at Bezymianny and Klyuchevskoy volcanoes, Central Kamchatka Depression

The Klyuchevskoy group of volcanoes in the Kamchatka arc erupts compositionally diverse magmas (high-Mg basalts to dacites) over small spatial scales. New high-precision Pb isotope data from modern juvenile (1956–present) erupted products and hosted enclaves and xenoliths from Bezymianny volcano reveal that Bezymianny and Klyuchevskoy volcanoes, separated by only 9 km, undergo varying degrees of crustal processing through independent crustal columns. Lead isotope compositions of Klyuchevskoy basalts–basaltic andesites are more radiogenic than Bezymianny andesites ([superscript 208]Pb/[superscript 204]Pb = 37.850–37.903, [superscript 207]Pb/[superscript 204]Pb = 15.468–15.480, and [superscript 206]Pb/[superscript 204]Pb = 18.249–18.278 at Bezymianny; [superscript 208]Pb/[superscript 204]Pb = 37.907–37.949, [superscript 207]Pb/[superscript 204]Pb = 15.478–15.487, and [superscript 206]Pb/[superscript 204]Pb = 18.289–18.305 at Klyuchevskoy). A mid-crustal xenolith with a crystallization pressure of 5.2 ± 0.6 kbars inferred from two-pyroxene geobarometry and basaltic andesite enclaves from Bezymianny record less radiogenic Pb isotope compositions than their host magmas. Hence, assimilation of such lithologies in the middle or lower crust can explain the Pb isotope data in Bezymianny andesites, although a component of magma mixing with less radiogenic mafic recharge magmas and possible mantle heterogeneity cannot be excluded. Lead isotope compositions for the Klyuchevskoy Group are less radiogenic than other arc segments (Karymsky—Eastern Volcanic Zone; Shiveluch—Northern Central Kamchatka Depression), which indicate increased lower-crustal assimilation beneath the Klyuchevskoy Group. Decadal timescale Pb isotope variations at Klyuchevskoy demonstrate rapid changes in the magnitude of assimilation at a volcanic center. Lead isotope data coupled with trace element data reflect the influence of crustal processes on magma compositions even in thin mafic volcanic arcs.University of Washington. Department of Earth and Space Science

Correction to “Isotopic characterization of aerosol organic carbon components over the eastern United States”

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): D15399, doi:10.1029/2012JD018478.2013-01-0

PIN6 is required for nectary auxin response and short stamen development

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/1/tpj12184-sup-0001-FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/2/tpj12184.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/3/tpj12184-sup-0004-FigS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/4/tpj12184-sup-0003-FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/5/tpj12184-sup-0002-FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98417/6/tpj12184-sup-0005-FigS5.pd

Fully reprogrammable 2D array of multistate molecular switching units

Integration of molecular switching units into complex electronic circuits is considered to be the next step toward the realization of novel logic and memory devices. This paper reports on an ordered 2D network of neighboring ternary switching units represented by triazatruxene (TAT) molecules organized in a honeycomb lattice on a Ag(111) surface. Using low-temperature scanning tunneling microscopy, the bonding configurations of individual TAT molecules can be controlled, realizing up to 12 distinct states per molecule. The switching between those states shows a strong bias dependence ranging from tens of millivolts to volts. The low-bias switching behavior is explored in active units consisting of two and more interacting TAT molecules that are purposefully defined (programmed) by high-bias switching within the honeycomb lattice. Within such a unit the low-bias switching can be triggered and accessed by single-point measurements on a single TAT molecule, demonstrating up to 9 and 19 distinguishable states in a dyad and a tetrad of coupled molecules, respectively. High experimental control over the desired state, owing to bias-dependent hierarchical switching and pronounced switching directionality, as well as full reversibility, make this system particularly appealing, paving the way to design complex molecule-based memory systems

An Australian longitudinal pilot study examining health determinants of cardiac outcomes 12 months post percutaneous coronary intervention

Background Percutaneous coronary intervention (PCI) is a very common revascularisation procedure for coronary artery disease (CAD). The purpose of this study was to evaluate cardiac outcomes, health related quality of life (HRQoL), resilience and adherence behaviours in patients who have undergone a PCI at two time points (6 and 12 months) following their procedure. Methods A longitudinal pilot study was conducted to observe the cardiac outcomes across a cohort of patients who had undergone a percutaneous coronary intervention (PCI). Participants who had undergone PCI 6 months prior were invited. Those participants who met the inclusion criteria and provided consent then completed a telephone survey (time point 1). These participants were then contacted 6 months later (i.e. 12 months post-intervention, time point 2) and the measures were repeated. Results All patients (n = 51) were recorded as being alive at time point 1. The multiple model indicated that controlling for other factors, gender was significantly associated with a linear combination of outcome measures (p = 0.004). The effect was moderate in magnitude (partial-η2 = 0.303), where males performed significantly better than females 6 months after the PCI procedure physically and with mood. Follow-up univariate ANOVAs indicated that gender differences were grounded in the scale measuring depression (PHQ9) (p = 0.005) and the physical component score of the short form measuring HRQoL (SF12-PCS) (p = 0.003). Thirteen patients were lost to follow-up between time points 1 and 2. One patient was confirmed to have passed away. The pattern of correlations between outcome measures at time point 2 revealed statistically significant negative correlation between the PHQ instrument and the resilience scale (CD-RISC) (r = -0.611; p < 0.001); and the physical component score of the SF-12 instrument (r = -0.437; p = 0.054). Conclusions Men were performing better than women in the 6 months post-PCI, particularly in the areas of mood (depression) and physical health. This pilot results indicate gender-sensitive practices are recommended particularly up to 6 months post-PCI. Any gender differences observed at 6 month appear to disappear at 12 months post-PCI. Further research into the management of mood particularly for women post-PCI is warranted. A more detailed inquiry related to access/attendance to secondary prevention is also warranted