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Background: Diagnostic error is a significant problem in specialities characterised by diagnostic uncertainty such as primary care, emergency medicine and paediatrics. Despite wide-spread availability, computerised aids have not been shown to significantly improve diagnostic decision-making in a real world environment, mainly due to the need for prolonged system consultation. In this study performed in the clinical environment, we used a Web-based diagnostic reminder system that provided rapid advice with free text data entry to examine its impact on clinicians' decisions in an acute paediatric setting during assessments characterised by diagnostic uncertainty.

Genes involved in the production of the extracellular (133)-␤-glucan, curdlan, by Agrobacterium sp. strain ATCC 31749 were described previously (Stasinopoulos et al., Glycobiology 9:31-41, 1999). To identify additional curdlan-related genes whose protein products occur in the cell envelope, the transposon TnphoA was used as a specific genetic probe. One mutant was unable to produce high-molecular-mass curdlan when a previously uncharacterized gene, pss AG , encoding a 30-kDa, membrane-associated phosphatidylserine synthase was disrupted. The membranes of the mutant lacked phosphatidylethanolamine (PE), whereas the phosphatidylcholine (PC) content was unchanged and that of both phosphatidylglycerol and cardiolipin was increased. In the mutant, the continued appearance of PC revealed that its production by this Agrobacterium strain is not solely dependent on PE in a pathway controlled by the Pss AG protein at its first step. Moreover, PC can be produced in a medium lacking choline. When the pss AG ::TnphoA mutation was complemented by the intact pss AG gene, both the curdlan deficiency and the phospholipid profile were restored to wild-type, demonstrating a functional relationship between these two characteristics. The effect of the changed phospholipid profile could occur through an alteration in the overall charge distribution on the membrane or a specific requirement for PE for the folding into or maintenance of an active conformation of any or all of the structural proteins involved in curdlan production or transport.

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This article shows how a large palaeontological database (the Plant Fossil Record version 2.2, available on the Internet) can be used to draw evolutionary and migratory pathways. 2946 published records of the family Aceraceae have been found as leaf, fruit and seed, wood or pollen fossils, and their geographical and stratigraphical distributions are presented here in different graphical forms. Manipulation and analysis of the data have produced palaeo-geographic maps of these distributions, curves of the number of records in five global regions over the last 100 million years, and cladograms of taxa and their geography. The results give objective evidence which shows that early members of the family became well established on upland slopes of the north Pacific rim during the Palaeogene. Some of these early species migrated eastwards across Greenland to Europe before the North Atlantic opened to the Arctic. Later and larger migrations started in the Oligocene, from Asia westwards to central Europe, bringing a diversification in species both there and in the regions of origin.