Atomic Transport in Dense, Multi-Component Metallic Liquids

Pd43Ni10Cu27P0 has been investigated in its equilibrium liquid state with incoherent, inelastic neutron scattering. As compared to simple liquids, liquid PdNiCuP is characterized by a dense packing with a packing fraction above 0.5. The intermediate scattering function exhibits a fast relaxation process that precedes structural relaxation. Structural relaxation obeys a time-temperature superposition that extends over a temperature range of 540K. The mode-coupling theory of the liquid to glass transition (MCT) gives a consistent description of the dynamics which governs the mass transport in liquid PdNiCuP alloys. MCT scaling laws extrapolate to a critical temperature Tc at about 20% below the liquidus temperature. Diffusivities derived from the mean relaxation times compare well with Co diffusivities from recent tracer diffusion measurements and diffsuivities calculated from viscosity via the Stokes-Einstein relation. In contrast to simple metallic liquids, the atomic transport in dense, liquid PdNiCuP is characterized by a drastical slowing down of dynamics on cooling, a q^{-2} dependence of the mean relaxation times at intermediate q and a vanishing isotope effect as a result of a highly collective transport mechanism. At temperatures as high as 2Tc diffusion in liquid PdNiCuP is as fast as in simple liquids at the melting point. However, the difference in the underlying atomic transport mechanism indicates that the diffusion mechanism in liquids is not controlled by the value of the diffusivity but rather by that of the packing fraction

Trends in influenza vaccination coverage rates in Germany over five seasons from 2001 to 2006

BACKGROUND: To assess influenza vaccination coverage from 2001 to 2006 in Germany, to understand drivers and barriers to vaccination and to identify vaccination intentions for season 2006/07. METHODS: 9,990 telephone-based household surveys from age 14 were conducted between 2001 and 2006. Essentially, the same questionnaire was used in all seasons. RESULTS: The influenza vaccination coverage rate reached 32.5% in 2005/06. In the elderly (> or years), the vaccination rate reached 58.9% in 2005/06. In those aged 65 years and older, it was 63.4%. Perceiving influenza as a serious illness was the most frequent reason for getting vaccinated. Thirteen percent of those vaccinated in 2005/06 indicated the threat of avian flu as a reason. The main reason for not getting vaccinated was thinking about it without putting it into practice. The major encouraging factor to vaccination was a recommendation by the family doctor. 49.6% of the respondents intend to get vaccinated against influenza in season 2006/07. CONCLUSION: Increasing vaccination rates were observed from 2001 to 2006 in Germany. The threat of avian influenza and the extended reimbursement programs may have contributed to the recent increase

Cross-Sectional Study on Influenza Vaccination, Germany, 1999–2000

To assess influenza vaccination coverage in Germany, we conducted a nationwide telephone survey in November 1999 in adults (>18 yrs) using random-digit dialing. Overall, 23% of 1,190 survey participants reported having been vaccinated (adjusted 18%) with 16% (adjusted 15%) in former West Germany versus 35% (adjusted 32%) in former East Germany. Immunization rates for vaccination target groups were lower in West Germany (21%) than in East Germany (40%). Seven percent of health-care workers were immunized. Previous influenza vaccination, positive attitudes towards immunization, and having a family physician increased the rate of vaccination; fear of adverse effects lowered the rate. Family physicians performed 93% of the vaccinations, which suggests their key role in improving low vaccination coverage in Germany. The fact that >71% (850/1,190) of participants belonged to at least one of the vaccination target groups recommended by the German Standing Commission on Immunization emphasizes the need to focus the definition of target groups

Polyelectrolyte Adsorption on Solid Surfaces: Theoretical Predictions and Experimental Measurements

This work utilizes a combination of theory and experiments to explore the adsorption of two different cationic polyelectrolytes onto oppositely charged silica surfaces at pH 9. Both polymers, poly(diallyldimethylammonium chloride), PDADMAC, and poly(4-vinyl N-methylpyridinium iodide), PVNP, are highly charged and highly soluble in water. Another important aspect is that a silica surface carries a relatively high surface charge density at this pH level. This means that we have specifically chosen to investigate adsorption under conditions where electrostatics can be expected to dominate the interactions. Of specific focus in this work is the response of the adsorption to the addition of simple salt (i.e., a process where electrostatics is gradually screened out). Theoretical predictions from a recently developed correlation-corrected classical density functional theory for polyelectrolytes are evaluated by direct quantitative comparisons with corresponding experimental data, as obtained by ellipsometry measurements. We find that, at low concentrations of simple salt, the adsorption increases with ionic strength, reaching a maximum at intermediate levels (about 200 mM). The adsorption then drops but retains a finite level even at very high salt concentrations, indicating the presence of nonelectrostatic contributions to the adsorption. In the theoretical treatment, the strength of this relatively modest but otherwise largely unknown nonelectrostatic surface affinity was estimated by matching predicted and experimental slopes of adsorption curves at high ionic strength. Given these estimates for the nonelectrostatic part, experimental adsorption data are essentially captured with quantitative accuracy by the classical density functional theory

Influenza vaccination coverage rates in Europe – covering five consecutive seasons (2001–2006) in five countries

Objective  To understand potential drivers and barriers to influenza vaccination in the general population. Methods  47 982 household surveys were conducted in five European countries between 2001 and 2006. Results  Overall influenza vaccination coverage increased over the years and reached 26·2% in 2005/06. Among the elderly ≥65 years, the rate increased significantly to 67·8% (2005/06). The most common reason for being vaccinated over the 5 years was the perception of influenza as a serious illness, which people want to avoid. The main reason for not getting vaccinated among those never previously vaccinated was feeling that they were unlikely to catch influenza. A recommendation by the family physician was the most encouraging factor for vaccination