Impact of dry density and incomplete saturation on microbial growth in bentonite clay for nuclear waste storage.

Aims: Many countries are in the process of designing a deep geological repository (DGR) for long-term storage of used nuclear fuel. For several designs, used fuel containers will be placed belowground, with emplacement tunnels being backfilled using a combination of highly compacted powdered bentonite clay buffer boxes surrounded by a granulated "gapfill" bentonite. To limit the potential for microbiologically influenced corrosion of used fuel containers, identifying conditions that suppress microbial growth is critical for sustainable DGR design.

Multicomponent Synthesis of Poly(α-aminophosphine chalcogenide)s and Subsequent Depolymerization.

Multicomponent reactions of primary phosphines (R-PH), diimines (R'-N═C(H)-R-(H)C═N-R'), and chalcogens (O, S) generate poly(α-aminophosphine chalcogenide)s (-) through step-growth polymerization. Characterization of the linear polymers using P{H} diffusion-ordered NMR spectroscopy (DOSY) experiments aided in determining the molecular weight () of the material. Subjecting the polyphosphine oxide or sulfide to reducing conditions in the presence of a Lewis acid resulted in complete depolymerization of the polymers, quantitatively releasing the 1° phosphine and diimine () starting materials, with concomitant reduction of diimine to diamine ().

Effect of gamma irradiation on gas-ionic liquid and water-ionic liquid interfacial stability.

The effect of γ-radiation on gas-ionic liquid (IL) and water-IL interfacial stability was investigated. Three phosphonium-based ILs, which vary considerably in their viscosity, conductivity and miscibility with water, were examined. The gas phase above the IL samples (headspace gas) was analyzed using gas chromatography with a mass spectrometer detector while the changes in the IL and aqueous phases were followed by conductivity measurements and Raman spectroscopy.

Protein oxidative modifications during electrospray ionization: solution phase electrochemistry or corona discharge-induced radical attack?

The exposure of solution-phase proteins to reactive oxygen species (ROS) causes oxidative modifications, giving rise to the formation of covalent +16 Da adducts. Electrospray ionization (ESI) mass spectrometry (MS) is the most widely used method for monitoring the extent of these modifications. Unfortunately, protein oxidation can also take place as an experimental artifact during ESI, such that it may be difficult to assess the actual level of oxidation in bulk solution.

Analyzing the influence of alloying elements and impurities on the localized reactivity of titanium grade-7 by scanning electrochemical microscopy.

Scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) was applied to investigate the grain boundaries on ASTM grade-7 titanium (Ti-7) with a freshly polished surface, and the results showed that the alloying element, Pd, and the impurity, Fe, cosegregated to grain boundaries. Scanning electrochemical microscopy (SECM) was used to study the variations in reactivity on Ti-7 exposed to an aerated neutral solution of 0.1 M NaCl.