University of Patras

About: University of Patras is a education organization based out in Pátrai, Greece. It is known for research contribution in the topics: Population & Catalysis. The organization has 13372 authors who have published 31263 publications receiving 677159 citations. The organization is also known as: Panepistímio Patrón.

Dependence of catalytic rates on catalyst work function

Abstract: THE catalytic activity and selectivity of metals can be altered dramatically and reversibly by supplying or removing oxide anions, O2–, at the metal catalyst surface by interfacing the catalyst with an O2– conductor such as zirconia1–6. This effect, termed non-faradaic electrochemical modification of catalytic activity (NEMCA), leads to a steady-state catalytic reaction rate increase up to 3 × 105 times higher than the rate of supply or removal of O2– at the catalyst surface1,3,4. Here we report that β"-Al2O3, which is a Na+ conductor, can also induce the NEMCA effect. Furthermore we show that the origin of the NEMCA effect lies in the controlled variation of catalyst work function on polarization of the metal-solid-electrolyte interface, and demonstrate that the rates of metal-catalysed reactions depend exponentially on the average catalyst work function. Thus the influence of catalyst electronic structure, rather than surface geometry, is here the key factor in catalytic activity.

The Cdt1 protein is required to license DNA for replication in fission yeast.

Abstract: To maintain genome stability in eukaryotic cells, DNA is licensed for replication only after the cell has completed mitosis, ensuring that DNA synthesis (S phase) occurs once every cell cycle1. This licensing control is thought to require the protein Cdc6 (Cdc18 in fission yeast) as a mediator for association of minichromosome maintenance (MCM) proteins with chromatin2,3,4,5,6,7,8,9,10. The control is overridden in fission yeast by overexpressing Cdc18 (ref. 11) which leads to continued DNA synthesis in the absence of mitosis12. Other factors acting in this control have been postulated13 and we have used a re-replication assay to identify Cdt1 (ref. 14) as one such factor. Cdt1 cooperates with Cdc18 to promote DNA replication, interacts with Cdc18, is located in the nucleus, and its concentration peaks as cells finish mitosis and proceed to S phase. Both Cdc18 and Cdt1 are required to load the MCM protein Cdc21 onto chromatin at the end of mitosis and this is necessary to initiate DNA replication. Genes related to Cdt1 have been found in Metazoa and plants (A. Whitaker, I. Roysman and T. Orr-Weaver, personal communication), suggesting that the cooperation of Cdc6/Cdc18 with Cdt1 to load MCM proteins onto chromatin may be a generally conserved feature of DNA licensing in eukaryotes.