Understanding the oxidation and reduction mechanisms of catalytically active transition metal nanoparticles is important to improve their application in a variety of chemical processes. In nanocatalysis the nanoparticles can undergo oxidation or reduction in situ, and thus the redox species are not what are observed before and after reactions. We have used the novel environmental scanning transmission electron microscope (ESTEM) with 0.1 nm resolution in systematic studies of complex dynamic oxidation and reduction mechanisms of copper nanoparticles. The oxidation of copper has previously been reported to be dependent on its crystallography and its interaction with the substrate. By following the dynamic oxidation process in situ in real time with high-angle annular dark-field imaging in the ESTEM, we use conditions ideal to track the oxidation front as it progresses across a copper nanoparticle by following the changes in the atomic number (Z) contrast with time. The oxidation occurs via the nucleation of the oxide phase (CuO) from one area of the nanoparticle which then progresses unidirectionally across the particle, with the Cu-to-CuO interface having a relationship of Cu{111}//CuO{111}. The oxidation kinetics are related to the temperature and oxygen pressure. When the process is reversed in hydrogen, the reduction process is observed to be similar to the oxidation, with the same crystallographic relationship between the two phases. The dynamic observations provide unique insights into redox mechanisms which are important to understanding and controlling the oxidation and reduction of copper-based nanoparticles.

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We aimed to study the relationship between the prescribing of lipid-lowering medication, social deprivation and other general practice characteristics. We conducted a cross-sectional survey of all general practices in England, 2004-05. For each practice, the following variables were obtained: standardized cost and volume data for lipid-lowering medication, descriptors of general practices, Index of Multiple Deprivation, 2004, ethnicity data from the 2001 Census and Quality and Outcomes Framework data. A regression model was constructed which explained 34.5% of the variation in statin prescribing by general practitioners. The most powerful predictors were higher social deprivation, higher prevalence of coronary heart disease and achievement of cholesterol targets for diabetics. Negative regression coefficients were demonstrated for the proportion of elderly patients in the practice and, to a lesser extent, for the proportion of south Asian and Afro-Caribbean patients. In conclusion, contrary to previous local studies, we found that statin prescribing was higher in more deprived communities, even after adjustment for increased disease prevalence and practice variables associated with deprivation. Statin prescribing was also independently associated with success at achieving cholesterol targets in established disease (secondary prevention). However, our findings suggest under-prescribing of statins to the elderly and possibly also to ethnic minorities.

The weightings (STAR-PUs) offer a sound basis for cost comparisons at the therapeutic group level. Cost-based weightings for overall prescribing derived from the IMS data were reassuringly similar to those of the existing ASTRO-PU system.

Understanding precursor transformation to active catalysts is crucial to heterogeneous Fischer-Tropsch (FT) catalysis directed towards production of hydrocarbons for transportation fuels. Despite considerable literature on FT catalysis, the effect of pre-treatment of supported cobalt catalysts on cobalt dispersion, dynamic atomic structure and the activity of the catalysts is not well understood. Here we present systematic studies into the formation of active catalyst phases in supported Co catalyst precursors in FT catalysis using in-situ environmental (scanning) transmission electron microscopy (E(S)TEM) with single atom resolution under controlled reaction environments for in-situ visualization, imaging and analysis of reacting atomic species in real time, EXAFS, XAS, DRIFTS analyses and catalytic activity measurements. We have synthesized and analyzed dried-reduced (D) and dried-calcined reduced (DC) Co real catalysts on reducible and non-reducible supports, such as SiO2, Al2O3, TiO2 and ZrO2. Comparisons of dynamic in-situ atomic structural observations of reacting single atoms, atomic clusters and nanoparticles of Co, DRIFTS, XAS, EXAFS and catalytic activity data of the D and DC samples reveal in most cases better dispersion in the D samples, leading to a larger number of low-coordination Co 0 sites and a higher number of active sites for CO adsorption. The experimental findings on the degree of reduction of D and DC catalysts on reducible and non-reducible supports and correlations between hexagonal (hcp) Co sites and the activity of the catalysts generate structural insights into the catalyst dynamics, important to the development of efficient FT catalysts.