Influence of thermal treatment on nanostructured gold model catalysts.

We fabricated films of Au onto single crystal alumina (Al(2)O(3)(0001)) and nanostructured the surface using a high resolution focused ion beam (FIB) to remove specific regions of the film. The nanostructures consist of lines and orthogonal lines cut into the film, resulting in one- and two-dimensional islands of gold. When these films are heated above 300 °C, small nanoparticles of gold form due to the dewetting of the Au film from the alumina surface. The dimensions of these islands are dictated by the nature of the nanopatterning. The isolated islands generally have the smallest nanoparticles after heating, while the unpatterned film has much larger particles. Sintering is reduced within the nanostructured metal domains due to isolation of Au islands from each other. The evaporation rate is higher within these islands, due to the smaller size of nanoparticles and hence the higher effective vapor pressure over the surface (the Kelvin effect).

Case of the month: "Oh! Drat!--A case of transcutaneous superwarfarin poisoning and its recurrent presentation".

Superwarfarin poisoning is considered a significant public health problem in the US. In 2004, there were 16,054 cases of poisoning; most were accidental ingestions of rat bait by children but 4576 patients required hospital treatment, 23 patients had major adverse outcomes and 1 patient died. Similar information is unavailable for the UK. The National Poisons Information Service is presently auditing cases. The case of a farmer who presented with haematuria, 9 days after spilling a rodenticide containing a superwarfarin over himself is reported here. He was physically well except for mild abdominal tenderness. He had grossly deranged clotting studies (prothrombin time (PT) >200 s, activated partial thromboplastin time (APTT) 56 s) that were rapidly corrected with fresh frozen plasma and vitamin K. He was sent home after 5 days without follow up. Unfortunately, he presented again 2 days later, again with haematuria and an international normalised ratio (INR) >10. He required inpatient treatment with high-dose vitamin K for 1 week. Upon discharge, he required daily vitamin K and INR monitoring for a further month. The original inpatient team had not identified the specific poison (chlorophacinone). They were unaware that superwarfarins are more potent and longer acting than warfarin, with toxic effects for weeks or even months, and that large doses of vitamin K are often required.