The authors have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth.
Scientists are probing the bottom – and building up new materials – thanks to the Office of Science’s Nanoscale Science Research Centers.
Ath Godelitsas's insight:
Scanning probes – which include scanning electron, scanning transmission and others – allow scientists to see incredible details at astonishingly small sizes; to visualize materials at the nanoscale, the level of molecules and even individual atoms.
The authors showed that sedimentary ratios of the radionuclides thorium-230 (230Th) and protactinium-231 (231Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of 231Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years.
The authors demonstrated the use of noncontact atomic force microscopy (AFM) to investigate reaction-induced changes in the detailed internal bond structure of individual oligo-(phenylene-1,2-ethynylenes) on Ag(100) as they undergo a series of cyclization processes,
The movement from the subjects during in vivo confocal Raman spectral measurements could change the measurement volume, leading to non-specific signals and inaccurate interpretation of the acquired spectrum.
The authors have characterized the small-scale structure of natural carbonate fault mirrors (FMs) from three different faults along a tectonically active region of the Dead Sea transform using Atomic Force Microscopy (AFM).
The authors present shear strength measurements of iron up to pressures experienced in the Earth’s core. Hydrostatic X-ray spectroscopy and non-hydrostatic radial X-ray diffraction measurements of the deviatoric strain in hexagonally close-packed iron uniquely determine its shear strength to pressures above 200 GPa at room temperature.
We have analyzed gallstones from four patients of Europe and particularly from England (including samples from a mother and a daughter) and Greece. All cholesterol gallstones examined are well enriched in potentially toxic metals (Pb, as well as Ni in one case) and metalloids (As also in one case) as compared to the global average. The position of Zn, which is a characteristic biometal, in the structure of cholesterol, was investigated by molecular simulation using the Accelrys Materials Studio® software.
The authors showed that mantle oxidation state varies systematically as a function of mantle source composition. Negative correlations between Fe3+/ΣFe ratios and indices of mantle enrichment such as 87Sr/86Sr, 208Pb/204Pb, Ba/La, and Nb/Zr ratios reveal that enriched mantle is more reduced than depleted mantle. Because upper mantle carbon may act to simultaneously reduce iron and generate melts that share geochemical traits with our reduced samples, we propose that carbon creates magmas at ridges that are reduced and enriched.
Both cinnabar (HgS) and metallic mercury (Hg0) were important resources throughout Andean prehistory. Cinnabar was used for millennia to make vermillion, a red pigment that was highly valued in pre-Hispanic Peru; metallic Hg0 has been used since the mid-16th century to conduct mercury amalgamation, an efficient process of extracting precious metals from ores.
The authors reported the occurrence of phosphite in early Archean marine carbonates at levels indicating that this was an abundant dissolved species in the ocean before 3.5 Ga. Additionally, we show that schreibersite readily reacts with an aqueous solution of glycerol to generate phosphite and the membrane biomolecule glycerol–phosphate under mild thermal conditions, with this synthesis using a mineral source of P. Phosphite derived from schreibersite was, hence, a plausible reagent in the prebiotic synthesis of phosphorylated biomolecules and was also present on the early Earth in quantities large enough to have affected the redox state of P in the ocean. Phosphorylated biomolecules like RNA may, thus, have first formed from the reaction of reduced P species with the prebiotic organic milieu on the early Earth.
The authors presented atomic-resolution microscopy data with unprecedented detail of the circumferences of nanosized rutile (α-TiO2) crystals previously used in studies of the adsorption of protons, cations, and amino acids.
Analysis of the X-ray absorption spectroscopy (XAS) spectra of sorbed complexes implied that monothioarsenate binds to Fe oxides as a monodentate, inner-sphere complex. In the presence of Fe sulfides, mono- and tetrathioarsenate were both unstable and partially reduced to arsenite.
The gemstones jadeite and ruby generally form as a result of the plate tectonic processes subduction and collision. Jade made of jadeite (jadeitite) forms when supercritical fluids released from subducting oceanic crust condense in the overlying mantle wedge, 20–120 km deep in the Earth.
National Geographic Billion-Year-Old Water Preserved in Canadian Mine - National Geographic News National Geographic "We're looking at billion-year-old rock here and we can still find flowing water that's full of the kind of energy that can support...
Elaborate nanostructures blossom from a chemical reaction perfected at Harvard
Ath Godelitsas's insight:
To create the flower structures, Noorduin and his colleagues dissolve barium chloride (a salt) and sodium silicate (also known as waterglass) into a beaker of water. Carbon dioxide from air naturally dissolves in the water, setting off a reaction which precipitates barium carbonate crystals...
Until recently, to prepare nanocrystals of a new material, scientists searched their shelves for the appropriate molecular precursors, surfactants, and solvents. They then optimized the reaction conditions for the atoms to self-assemble into monodisperse nanocrystals. This approach is being replaced by a simpler strategy, in which preformed nanocrystals serve as templates to produce nanoparticles with a different composition through chemical transformation.
Teeth from human children and captive macaques, with prospectively recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother’s milk through the weaning process. Dietary transitions in a Middle Palaeolithic juvenile Neanderthal, showed a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation.
A large paleo-river of Miocene age traversing Libya from south to north has been previously demonstrated by seismic, stratigraphic, paleontological, and remote sensing data.However, the source of this major African paleo-river has remained controversial. Dark-colored sedimentary material with magnetic properties suggested a source from the basaltic Haruj as Aswad massif in south central Libya. To test this hypothesis, mineralogical and geochemical study of clayey sediments from fossiliferous zones, were carried out. Results strongly indicate very mature and re-processed sediments of continental origin, and felsic sources with no basaltic contribution. Thus the origin can be traced to an upland area of outcrop of rocks of Precambrian continental origin in northeastern Chad.
Th authors used TEM and STXM (coupled with XANES) to discuss the role of bacteria in the fossilization mechanism and propose that they could have played an active role in the formation of francolite in phosphorites.
"...Working with researchers at the National Synchrotron Light Source (NSLS), Cottrell and Kelley fine-tuned a technique called micro x-ray absorption near-edge structure spectroscopy to determine the oxidation state of iron in a variety of glass samples from different tectonic areas..."