Mn12_{12}-Acetate Complexes Studied as Single Molecules

The phenomenon of single molecule magnet (SMM) behavior of mixed valent Mn12 coordination clusters of general formula [Mn$^{III}$$_{8}$Mn$^{IV}$$_{4}$O$_{12}$(RCOO)$_{16}$(H$_{2}$O)$_{4}$] had been exemplified by bulk samples of the archetypal [Mn$^{III}$$_{8}$Mn$^{IV}$$_{4}$O$_{12}$(CH$_{3}$COO)$_{16}$(H$_{2}$O)$_{4}$] (4) molecule, and the molecular origin of the observed magnetic behavior has found support from extensive studies on the Mn12 system within crystalline material or on molecules attached to a variety of surfaces. Here we report the magnetic signature of the isolated cationic species [Mn$_{12}$O$_{12}$(CH$_{3}$COO)$_{15}$(CH$_{3}$CN)]$^{+}$ (1) by gas phase X-ray Magnetic Circular Dichroism (XMCD) spectroscopy, and we find it closely resembling that of the corresponding bulk samples. Furthermore, we report broken symmetry DFT calculations of spin densities and single ion tensors of the isolated, optimized complexes [Mn$_{12}$O$_{12}$(CH$_{3}$COO)$_{15}$(CH$_{3}$CN)]$^{+}$ (1), [[Mn$_{12}$O$_{12}$(CH$_{3}$COO)$_{16}$] (2), [Mn$_{12}$O$_{12}$(CH$_{3}$COO)$_{16}$(H$_{2}$O)$_{4}$] (3), and the complex in bulk geometry [Mn$^{III}$$_{8}$Mn$^{IV}$$_{4}$O$_{12}$(CH$_{3}$COO)$_{16}$(H$_{2}$O)$_{4}$] (5). The found magnetic fingerprints – experiment and theory alike – are of a remarkable robustness: The Mn$^{IV}$$_{4}$ core bears almost no magnetic anisotropy while the surrounding MnIII8 ring is highly anisotropic. These signatures are truly intrinsic properties of the Mn$_{12}$ core scaffold within all of these complexes and largely void of the environment. This likely holds irrespective of bulk packing effects

Standardization of measles, mumps and rubella assays to enable comparisons of seroprevalence data across 21 European countries and Australia

The aim of the European Sero-Epidemiology Network is to establish comparability of the serological surveillance of vaccine-preventable diseases in Europe. The designated reference laboratory (RL) for measles, mumps, rubella (MMR) prepared and tested a panel of 151 sera by the reference enzyme immunoassay (rEIA). Laboratories in 21 countries tested the panel for antibodies against MMR using their usual assay (a total of 16 different EIAs) and the results were plotted against the reference results in order to obtain equations for the standardization of national serum surveys. The RL also tested the panel by the plaque neutralization test (PNT). Large differences in qualitative results were found compared to the RL. Well-fitting standardization equations with R20·8 were obtained for almost all laboratories through regression of the quantitative results against those of the RL. When compared to PNT, the rEIA had a sensitivity of 95·3%, 92·8% and 100% and a specificity of 100%, 87·1% and 92·8% for measles, mumps and rubella, respectively. The need for standardization was highlighted by substantial inter-country differences. Standardization was successful and the selected standardization equations allowed the conversion of local serological results into common units and enabled direct comparison of seroprevalence data of the participating countrie

Global Mortality Estimates for the 2009 Influenza Pandemic from the GLaMOR Project: A Modeling Study

Background: Assessing the mortality impact of the 2009 influenza A H1N1 virus (H1N1pdm09) is essential for optimizing public health responses to future pandemics. The World Health Organization reported 18,631 laboratory-confirmed pandemic deaths, but the total pandemic mortality burden was substantially higher. We estimated the 2009 pandemic mortality burden through statistical modeling of mortality data from multiple countries. Methods and Findings: We obtained weekly virology and underlying cause-of-death mortality time series for 2005–2009 for 20 countries covering ~35% of the world population. We applied a multivariate linear regression model to estimate pandemic respiratory mortality in each collaborating country. We then used these results plus ten country indicators in a multiple imputation model to project the mortality burden in all world countries. Between 123,000 and 203,000 pandemic respiratory deaths were estimated globally for the last 9 mo of 2009. The majority (62%–85%) were attributed to persons under 65 y of age. We observed a striking regional heterogeneity, with almost 20-fold higher mortality in some countries in the Americas than in Europe. The model attributed 148,000–249,000 respiratory deaths to influenza in an average pre-pandemic season, with only 19% in person

Measles virus spread initiated at international mass gatherings in Europe, 2011

Three parallel transmission chains of measles virus (MV) variant ‘D8-Villupuram’ (D8-V) originated from two coinciding international mass gathering (MG) events in Rimini, Italy, in June 2011. MV D8-V was independently introduced into Germany by two unvaccinated persons, and into Slovenia by one unvaccinated person who had attended these events. Secondary spread of D8-V was restricted to two generations of transmission in Slovenia as well as in Germany where the virus was further disseminated at another MG. Serological and epidemiological investigation of the D8-V-associated German and Slovenian cases revealed different antibody responses and age distributions. Primary infected young persons between 11 and 27 years-old were affected in Germany, whereas the group of Slovenian cases comprised adults aged from 28 to 47 years and a high proportion (9/14; 64%) of patients with secondary vaccine failure (SVF). Our study demonstrates that monitoring of MV transmission chains in an international context and adequate serological investigation of cases with remote vaccination can contribute to identify susceptibility gaps

Predominance of influenza A(H1N1)pdm09 virus genetic subclade 6B.1 and influenza B/Victoria lineage viruses at the start of the 2015/16 influenza season in Europe

Influenza A(H1N1)pdm09 viruses predominated in the European influenza 2015/16 season. Most analysed viruses clustered in a new genetic subclade 6B.1, antigenically similar to the northern hemisphere vaccine component A/California/7/2009. The predominant influenza B lineage was Victoria compared with Yamagata in the previous season. It remains to be evaluated at the end of the season if these changes affected the effectiveness of the vaccine for the 2015/16 season

Estimating seroprevalence of vaccine-preventable infections: is it worth standardizing the serological outcomes to adjust for different assays and laboratories?

The aim of the European Sero-Epidemiology Network 2 (ESEN2) project was to estimate age-specific seroprevalence for a number of vaccine-preventable diseases in Europe. To achieve this serosurveys were collected by 22 national laboratories. To adjust for a variety of laboratory methods and assays, all quantitative results were transformed to a reference laboratory’s units and were then classified as positive or negative to obtain age-specific seroprevalence. The aim of this study was to assess the value of standardization by comparing the crude and standardized seroprevalence estimates. Seroprevalence was estimated for measles, mumps, rubella, diphtheria, varicella zoster and hepatitis A virus (HAV) and compared before and after serological results had been standardized. The results showed that if no such adjustment had taken place, seroprevalence would have differed by an average of 3·2% (95% bootstrap interval 2·9–3·6) although this percentage varied substantially by antigen. These differences were as high as 16% for some serosurveys (HAV) which means that standardization could have a considerable impact on seroprevalence estimates and should be considered when comparing serosurveys performed in different laboratories using different assay methods

Measles virus spread initiated at international mass gatherings in Europe, 2011

Three parallel transmission chains of measles virus (MV) variant ‘D8-Villupuram’ (D8-V) originated from two coinciding international mass gathering (MG) events in Rimini, Italy, in June 2011. MV D8-V was independently introduced into Germany by two unvaccinated persons, and into Slovenia by one unvaccinated person who had attended these events. Secondary spread of D8-V was restricted to two generations of transmission in Slovenia as well as in Germany where the virus was further disseminated at another MG. Serological and epidemiological investigation of the D8-V-associated German and Slovenian cases revealed different antibody responses and age distributions. Primary infected young persons between 11 and 27 years-old were affected in Germany, whereas the group of Slovenian cases comprised adults aged from 28 to 47 years and a high proportion (9/14; 64%) of patients with secondary vaccine failure (SVF). Our study demonstrates that monitoring of MV transmission chains in an international context and adequate serological investigation of cases with remote vaccination can contribute to identify susceptibility gaps