A5085877860- Astro and Planetary Science
- Geological and Geochemical Analysis
- Planetary Science and Exploration
- High-pressure geophysics and materials
- Isotope Analysis in Ecology
- Space Exploration and Technology
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Geomagnetism and Paleomagnetism Studies
- Paleontology and Stratigraphy of Fossils
- earthquake and tectonic studies
- Astronomical and nuclear sciences
- Mineralogy and Gemology Studies
- Radioactive element chemistry and processing
- Nuclear Physics and Applications
- Laser-induced spectroscopy and plasma
- Stellar, planetary, and galactic studies
- Methane Hydrates and Related Phenomena
- Extraction and Separation Processes
- Hydrocarbon exploration and reservoir analysis
- Spacecraft and Cryogenic Technologies
- Metallurgical Processes and Thermodynamics
- Ion-surface interactions and analysis
- Nuclear Materials and Properties
Florida State University
2016-2025
National High Magnetic Field Laboratory
2016-2025
Prince Sultan University
2025
NOAA Oceanic and Atmospheric Research
2025
University of Calgary
2024
University of Roehampton
2024
University of Chicago
1995-2008
University of Vermont
2004-2005
University of Maryland, College Park
2005
University of Bern
2005
The cell wall envelope of Gram-positive pathogens functions as a scaffold for the attachment virulence factors and sieve that prevents diffusion molecules. Here isd genes (iron-regulated surface determinant) Staphylococcus aureus were found to encode responsible hemoglobin binding passage heme-iron cytoplasm, where it acts an essential nutrient. Heme-iron required two sortases tether Isd proteins unique locations within wall. Thus, appears act import apparatus uses wall–anchored relay across...
Although bacteria use different iron compounds in vitGro, the possibility that microbes distinguish between these sources during infection has hitherto not been examined. We applied stable isotope labeling to detect source-specific by mass spectrometry and show Staphylococcus aureus preferentially imports heme over transferrin iron. By combining this approach with computational genome analysis, we identified hts (heme transport system), a gene cluster promotes preferred import S. aureus....
ABSTRACT The pathogenesis of human infections caused by the gram-positive microbe Staphylococcus aureus has been previously shown to be reliant on acquisition iron from host hemoproteins. iron-regulated surface determinant system (Isd) encodes a heme transport apparatus containing three cell wall-anchored proteins (IsdA, IsdB, and IsdH) that are exposed staphylococcal hence have potential interact with Here we report S. can utilize hemoproteins hemoglobin myoglobin, but not hemopexin, as...
Chemical interaction of Earth's mantle with the liquid outer core should influence mantle's iron content. Osmium isotope ratios in Hawaiian lavas indicate a mass flux </=1% to mantle, which is immediate source these lavas. We present precise measurements Fe/Mn ratio for lavas, revealing an increase 1 2% mole fraction beneath Hawaii. This corresponds density anomaly about 0.5%, same magnitude observed seismic tomography models Pacific superswell region. These data also rule out role Mn-rich...
Tungsten isotopes are the ideal tracers of core-mantle chemical interaction.Given that W is moderately siderophile, it preferentially partitioned into Earth's core during its segregation, leaving mantle depleted in this element.In contrast, Hf lithophile, and short-lived radioactive isotope 182 decayed entirely to after metal-silicate segregation.Therefore, isotopic composition expected differ by about 200 ppm.Here, we report new high precision data for mantle-derived rock samples from...
Executive Summary Return of samples from the surface Mars has been a goal international science community for many years. Affirmation by NASA and ESA importance exploration led agencies to establish MSR Objectives Samples Team ( iMOST ). The purpose team is re‐evaluate update sample‐related engineering objectives Sample ) campaign. also undertaken define measurements types that can best address objectives. Seven have defined , traceable through two decades previously published priorities....
Calcium silicate perovskite, CaSiO3, is arguably the most geochemically important phase in lower mantle, because it concentrates elements that are incompatible upper including heat-generating thorium and uranium, which have half-lives longer than geologic history of Earth. We report CaSiO3-perovskite as an approved mineral (IMA2020-012a) with name davemaoite. The natural specimen davemaoite proves existence compositional heterogeneity within mantle. Our observations indicate also hosts...
To determine the degree to which matrix affects elemental abundance measurements in LA-ICP-MS analysis, and describe these effects term of properties, we measured sensitivity ratios (ESRs) from a multi-element solution laser ablation range silicate reference materials (SRM 61X series, MPI-DING glasses, USGS basalt glasses). For all analyses, ESRs depend strongly on element mass first ionization potential (FIP), as expected. nearly transparent SRM 612, show an additional dependence...
Martian meteorite NWA 7533 is a regolith breccia that compositionally resembles the surface measured by orbiters and landers. contains monzonitic clasts have zircon with U–Pb ages of 4.428 Ga. The Pb isotopic compositions plagioclase alkali feldspars, as well chlorapatite in been Secondary Ion Mass Spectrometry (SIMS). from yield an age 1.357±81 Ga (2σ). least radiogenic K-feldspar lie within error Geochron. These data indicate are product differentiation history includes residence reservoir...
Abstract Elemental abundances for volatile siderophile and chalcophile elements Mars inform us about processes of accretion core formation. Such data are few Martian meteorites, often lacking in the growing number desert finds. In this study, we employed laser ablation inductively coupled plasma–mass spectrometry ( LA ‐ ICP MS ) to analyze polished slabs 15 meteorites 70 elements. This technique has high sensitivity, excellent precision, is generally accurate as determined by comparisons...