Matthew A. Marcus

TL;DR: The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study, and preliminary examination shows that the nonvolatile portion of the comet is an unequilibrated assortment of materials that have both presolar and solar system origin.

TL;DR: The bulk of the comet 81P/Wild 2 samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger ferromagnesian silicates, Fe-Ni sulfides,Fe-Ni metal, and accessory phases.

TL;DR: In this article, the authors present the most catastrophic actual examples of the second type, where a modification of the chemistry of deep sediment layers by intensive well drillings and pumping of drinking water has led to vast arsenic remobilization and poisoning of ecosystems.

TL;DR: This work elucidates more properties and tries to understand the inner workings of black TiO2 nanoparticles with hydrogenated disorders in a surface layer surrounding a crystalline core, and suggests that the enhanced hydrogen mobility may be explained by the presence of the hydrogenated, disordered surface layer.

TL;DR: In this article, the authors used Synchrotron-based X-ray radiation microfluorescence (μ-SXRF) and micro-focused and powder extended Xray absorption fine structure (EXAFS) spectroscopy measurements, combined with desorption experiments and thermodynamic calculations, were used to evaluate the solubility of metal contaminants (Zn, Cu, Pb) and determine the nature and fractional amount of Zn species in a near neutral pH (6.5-7.0) truck-farming soil contaminated by sewage irrigation for