Efficient and selective hydrogen generation from bioethanol using ruthenium pincer-type complexes.

Catalytic generation of hydrogen from aqueous ethanol solution proceeds in the presence of pincer-type transition metal catalysts. Optimal results are obtained applying a [Ru(H)(Cl)(CO)(iPr2PEtN(H)EtPiPr2)] complex (catalyst TON 80,000) in the presence of water and base. This dehydrogenation reaction provides up to 70% acetic acid in a selective manner. For the first time, it is shown that bioethanol obtained from fermentation processes can be used directly in this protocol without the need for water removal. The produced hydrogen can be directly utilized in proton exchange membrane (PEM) fuel cells, since very low amounts of CO are formed.

Selective hydrogen production from methanol with a defined iron pincer catalyst under mild conditions.

Molecularly well-defined iron pincer complexes promote the aqueous-phase reforming of methanol to carbon dioxide and hydrogen, which is of interest in the context of a methanol and hydrogen economy. For the first time, the use of earth-abundant iron complexes under mild conditions for efficient hydrogen generation from alcohols is demonstrated.

Contribution of CD8+ T cells to innate immunity: IFN-gamma secretion induced by IL-12 and IL-18.

The role of CD8+ T cells in adaptive immunity is well documented and involves numerous effector mechanisms including direct cytolysis of targets and secretion of cytokines. The role of CD8+ T cells in innate immunity has not been previously appreciated. Using J774 macrophages infected in vitro with the intracellular bacterium, Listeria monocytogenes (LM), we show that CD8+ T cells isolated from naïve C57BL/6 (B6) mice respond rapidly by secreting IFN-gamma. CD8+ T cells secreting IFN-gamma can also be found in naïve B6 mice 16 h after infection with LM. This rapid IFN-gamma response is TCR-independent and mediated through the actions of IL-12 and IL-18. Cell surface staining and cell sorting experiments indicate that these novel CD8+ T cells express memory markers. In vitro CFSE-labeling experiments show that IFN-gamma-secreting CD8+ T cells proliferate rapidly after 2 days in culture and after 4 days constitute the majority of the CD8+ T cell population. Together, these data suggest an important role for IFN-gamma-secreting CD8+ T cells in the innate response to bacterial pathogens.