Can dawsonite permanently trap CO2?

Thermodynamic calculations indicate that although dawsonite (NaAlCO3(OH)2) is favored to form at the high CO2 pressures associated with carbon dioxide injection into sandstone reservoirs, this mineral will become unstable as CO2 pressure decreases following injection. To assess the degree to which dawsonite will persist following its formation in sandstone reservoirs, its dissolution rates have been measured at 80 +/- 3 degrees C as a function of pH from 3 to 10. Measured dawsonite dissolution rates normalized to their BET surface area are found to be nearly independent of pH over the range of 3.5 < pH < 8.6 at 1.58 x 10(-9) mol/(m2 x s). Use of these dissolution rates in reactive transport calculations indicate that dawsonite rapidly dissolves following the decrease of CO2 pressure out of its stability field, leading mainly to the precipitation of secondary kaolinite. This result indicates that dawsonite will provide a permanent mineral storage host only in systems that maintain high CO2 pressures, whereas dawsonite may be an ephemeral phase in dynamic settings and dissolve once high CO2 pressure dissipates either through dispersion or leakage.     

Fatty acid and oxylipin concentration differ markedly between different fetal bovine serums: A cautionary note

Fetal bovine serum (FBS) has been used as a universal supplement in cell culture for more than six decades. This includes the investigation of lipid and lipid mediator formation and biology. Little is known about the (polyunsaturated) fatty acid composition and their oxidation products in FBS. Therefore, we analyzed six different FBS purchased from three different companies regarding their fatty acid and oxylipin concentrations. We found pronounced differences in the fatty acid concentrations. Even two batches of “standardized” FBS batches from one company showed drastic differences (e.g., for eicosapentaenoic acid 5 ± 1 μM vs. 11 ± 1 μM). Oxylipin concentrations also markedly differ between the FBS lots. The highest differences were found for 12-lipoxygenase products (e.g., 12-hydroxyeicosatetraenoic acid free 21–87 nM and total 58–108 nM), probably due to inconsistent serum generation procedures. Our results indicate that for cell culture studies dealing with lipid metabolism, researchers should carefully characterize their used FBS to ensure reliability and reproducibility of study outcomes.     

Effects of substrate annealing on the gold-catalyzed growth of ZnO nanostructures

The effects of thermal substrate pretreatment on the growth of Au-catalyzed ZnO nanostructures by pulsed laser deposition are investigated. C-plane sapphire substrates are annealed prior to deposition of a thin Au layer. Subsequent ZnO growths on substrates annealed above 1,200°C resulted in a high density of nanosheets and nanowires, whereas lower temperatures led to low nanostructure densities. Separate Au film annealing experiments at 700°C showed little variation in the size and density of the Au catalyst droplets with substrate annealing temperature. The observed variation in the density of nanostructures is attributed to the number of surface nucleation sites on the substrate, leading to a competition between nucleation promoted by the Au catalyst and surface nucleation sites on the rougher surfaces annealed below 1,200°C.     

Bioactive Derivatives of Isopropylstilbene from Mutasynthesis and Chemical Synthesis

Isopropylstilbene is a natural product from Photorhabdus luminescens TT01, with multiple biological activities. A mutant deficient in the production of both anthraquinones and cinnamic acid was constructed, thus giving a clean background according to UV detection. This anthraquinone and stilbene deficient (ASD) mutant was used in mutasynthesis experiments to obtain new stilbene derivatives, which were detected by GC–MS. The structures of the new derivatives were confirmed by detailed MS analysis and then chemically synthesised; all of the natural and synthetic compounds were tested against protozoa that cause tropical diseases. Two compounds obtained by mutasynthesis showed the highest activity against Trypanosoma cruzi, the causative agent of Chagas disease, and Leishmania donovani, which causes leishmaniasis.     

Recommendations for Capacity Development in Water Resources Engineering and Environmental Management in Latin America

Socioeconomic development often causes environmental and water related problems. Any solution requires knowledge, willingness and sufficient financial and technical means. Such capacity is limited in many developing and threshold countries. To identify opportunities for strengthening capacity in water and environmental management, we analysed University curricula, identified synergies between Universities and practice, explored the potential of vocational training and awareness raising, and developed regional concepts for risk communication. The results present ways how Universities can make capacity development in the water sector in Latin America more efficient. We recommend to modernize curricula, to strengthen vocational training, to intensify public involvement and cooperation with practice, and provide methodological advice for implementation.