Posts Tagged ‘Chemistry’

NAS Member, Foreign Associate Share 2017 Nobel in Chemistry

The Nobel Prize in Chemistry was awarded to NAS member Joachim Frank, NAS foreign associate Richard Henderson, and Jacques Dubochet for developing cryo-electron microscopy for the high-resolution structure determination of biomolecules in solution.

Researchers develop first ‘living’ cancer treatment

Nanomachines capable of drilling holes in the membranes of individual cells could soon be a new weapon in the battle against cancer, as new research has demonstrated that the motorized molecules can effectively be used to kill off tumor cells in a mere 60 seconds. The breakthrough, described in a report published Thursday by The […]

The post Researchers develop first ‘living’ cancer treatment appeared first on Redorbit.

Can ‘mood ring’ sensors warn before bridges fail?

Scientists are working with “mood ring” materials as a potential way to minimize and mitigate […]

The post Can ‘mood ring’ sensors warn before bridges fail? appeared first on Futurity.

Implications for metal and volatile cycles from the pH of subduction zone fluids

The chemistry of aqueous fluids controls the transport and exchange—the cycles—of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth’s interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid–rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones. We find that the pH of fluids in subducted crustal lithologies is confined to a mildly alkaline range, modulated by rock volatile and chlorine contents. Cold subduction typical of the Phanerozoic eon favours the preservation of oxidized carbon in subducting slabs. In contrast, the pH of mantle wedge fluids is very sensitive to minor variations in rock composition. These variations may be caused by intramantle differentiation, or by infiltration of fluids enriched in alkali components extracted from the subducted crust. The sensitivity of pH to soluble elements in low abundance in the host rocks, such as carbon, alkali metals and halogens, illustrates a feedback between the chemistry of the Earth’s atmosphere–ocean system and the speciation of subduction zone fluids via the composition of the seawater-altered oceanic lithosphere. Our findings provide a perspective on the controlling reactions that have coupled metal and volatile cycles in subduction zones for more than 3 billion years7.

Powered by WordPress | Designed by: video game | Thanks to search engine optimization, seo agency and Privater Sicherheitsdienst