High performance metal-supported solid oxide fuel cells with Gd-doped ceria barrier layers

Metal-supported solid oxide fuel cells are believed to have commercial advantages compared to conventional anode (Ni-YSZ) supported cells, with the metal-supported cells having lower material costs, increased tolerance to mechanical and thermal stresses, and lower operational temperatures. The implementation of a metallic support has been challenged by the need to revise the cell fabrication route, as well as electrode microstructures and material choices, to compete with the energy output and stability of full ceramic cells.The metal-supported SOFC design developed at Risø DTU has been improved, and an electrochemical performance beyond the state-of-the-art anode-supported SOFC is demonstrated possible, by introducing a CGO barrier layer in combination with Sr-doped lanthanum cobalt oxide (LSC) cathode. Area specific resistances (ASR) down to 0.27 Ω cm², corresponding to a maximum power density of 1.14 W cm⁻² at 650 °C and 0.6 V, were obtained on cells with barrier layers fabricated by magnetron sputtering. The performance is dependent on the density of the barrier layer, indicating Sr²⁺ diffusion is occurring at the intermediate SOFC temperatures. The optimized design further demonstrate improved durability with steady degradation rates of 0.9% kh⁻¹ in cell voltage for up to 3000 h galvanostatic testing at 650 °C and 0.25 A cm⁻².     

Leaching of metribuzin metabolites and the associated contamination of a sandy Danish aquifer

As degradation products of metribuzin have received little attention as potential groundwater contaminants, we evaluated leaching of metribuzin and its primary metabolites desaminometribuzin (DA), desaminodiketometribuzin (DADK), and diketometribuzin (DK) at a sandy test site in Denmark. Soil water and groundwater were sampled monthly over a four-year period. Leaching of metribuzin and DA was negligible. DK and DADK leached from the root zone (1 meter below ground surface (mbgs)) in average concentrations considerably exceeding the EU limit value for drinking water (0.1 microg/L). Both metabolites appear to be relatively stable and persisted in soil water and groundwater several years after application. Past application of metribuzin at the site had contaminated the groundwater with both DK and DADK, which were detected in 99% and 48%, respectively, of the groundwater samples analyzed. Except for three of the groundwater samples, the DADK concentration never exceeded the EU limit value. In contrast, the annual concentration of DK exceeded 0.1 microg/L at 90% of the screens analyzed. The present findings suggest that as the degradation products of metribuzin can leach through sandy soil in high concentrations, they could potentially contaminate the groundwater. In view of this risk DK and DADK should both be included in monitoring programs and their ecotoxicological effects should be further investigated.     

Discovery of a Lead Brain-Penetrating Gonadotropin-Releasing Hormone Receptor Antagonist with Saturable Binding in Brain

We report the synthesis, radiosynthesis and biological characterisation of two gonadotropin-releasing hormone receptor (GnRH−R) antagonists with nanomolar binding affinity. A small library of GnRH−R antagonists was synthesised in 20–67 % overall yield with the aim of identifying a high-affinity antagonist capable of crossing the blood–brain barrier. Binding affinity to rat GnRH−R was determined by autoradiography in competitive-binding studies against [¹²⁵I]buserelin, and inhibition constants were calculated by using the Cheng–Prusoff equation. The radioligands were obtained in 46–79 % radiochemical yield and >95 % purity and with a molar activity of 19–38 MBq/nmol by direct nucleophilic radiofluorination. Positron emission tomography imaging in rat under baseline conditions in comparison to pretreatment with a receptor-saturating dose of GnRH antagonist revealed saturable uptake (0.1 %ID/mL) into the brain.     

The survival and persistence in the human gastrointestinal tract of five potential probiotic lactobacilli consumed as freeze-dried cultures or as probiotic sausage

Among five lactobacilli (L. plantarum MF1291, MF1298, DC13, L. pentosus MF1300 and L. salivarius DC5) which were administrated as freeze-dried cultures for 17 volunteers, MF1298 and DC13 were the most frequently reisolated strains in faeces demonstrating the human gastric survival of these strains. Furthermore, MF1298 and DC13 persisted in the same volunteer after ended intake, suggesting host-specific persistence behaviour. When MF1298 was administrated as sausage fermented with this strain, the number of volunteers harbouring MF1298 increased from 4 to 10 indicating that the sausage matrix protects the survival through the gastrointestinal tract (GIT).