A multiplex ligation detection assay for the characterization of Salmonella enterica strains

A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube? microarray detection. The feasibility of the developed assay was verified in a method comparison study with conventional PCR using 16 Salmonella 'test' strains comprising eight serovars. Subsequently, the feasibility of the LDR microarray assay was also tested by analyzing 41 strains belonging to 23 serovars. With the exception of four serovars each serovar was characterized by a unique virulence associated gene repertoire. The LDR microarray platform proved to be a convenient, rapid and easy to use tool with potential in tracing a Salmonella contamination in the food chain, for outbreak studies, and to provide data for risk assessors that support bio-traceability models.     

Sub-micrometer particulate air pollution and cardiovascular mortality in Beijing, China

Background

While the link between particulate matter and cardiovascular mortality is well established, it is not fully investigated and understood which properties of the aerosol might be responsible for the health effects, especially in polluted mega-city areas.

Objectives

Our goal was to explore the association between daily cardiovascular mortality and different particle metrics in the sub-micrometer range in Beijing, China.

Methods

We obtained daily counts of cause-specific cardiovascular deaths in the Beijing urban area for the period March 2004 to August 2005. Concurrently, continuous measurements of particle number size distributions were performed. Particle number concentrations (NC) between 0.003 μm and 0.8 μm were converted to particle mass and surface area concentrations assuming spherical particles. Semi-parametric Poisson regression models adjusting for trend, seasonality, day of the week, and meteorology were used to estimate immediate, delayed and cumulative particle effects. Additionally, effect modification by air mass origin was investigated.

Results

We observed associations between daily cardiovascular mortality and particle NC for a 2-days delay. Moreover, nearly all particle metrics showed 2-days delayed associations with ischemic heart disease mortality. The strongest association was found for particle NC in the size range 0.03-0.1 μm (7.1% increase in daily mortality with a 95%-confidence interval of 2.9%-11.5%, per an increase of 6250 particles/cm³). Results for surface and mass concentrations with a lag of two days indicated effect modification by air mass origin, whereas effects of particle NC were not modified.

Conclusions

Results show an elevated risk of cardiovascular mortality in Beijing from short-term exposure to particulate air pollution in the sub-micrometer range. Results also indicate that locally produced smaller particles and regionally transported particles may exhibit different effects in Beijing.     

Resonant cavity-enhanced mercury cadmium telluride detectors

The next-generation mercury cadmium telluride (HgCdTe) detectors will need to be able to spectrally resolve images to a degree far exceeding that currently available in two or even three color techniques. However, narrow, spectral pass bands will result in very low photon flux impinging on a detector. This paper investigates the use of resonant cavity-enhanced (RCE) detectors as a means of improving signal-to-noise performance of narrow spectral-width infrared (IR) detection systems.     

Optimal algorithms for dissemination of information in some interconnection networks

The problems of gossiping and broadcasting in one-way communication mode are considered for some prominent families of graphs. The complexity is measured as the number of communication rounds in the gossip and broadcast algorithms. The main result of the paper is the precise estimation of the gossip-problem complexity in cycles. To obtain this result a new combinatorial analysis of gossiping in cycles is developed. This analysis leads to an optimal lower bound on the number of rounds, and also to the design of an optimal algorithm for gossiping in cycles. The optimal algorithm for gossiping is later used to design new, effective algorithms for gossiping in important families of interconnection networks (cube connected cycles, butterfly networks). Furthermore, a new, effective algorithm for broadcasting in shuffle-exchange networks is developed.On leave from Comenius University, Bratislava, Czechoslovakia.     

Electrochemical investigations on the influence of electrolyte composition of Watts baths with special regard to throwing power

The influence of a variety of substances on technically relevant parameters of a nickel electroplating electrolyte (Watts bath) has been investigated. Special attention has been paid to the throwing power (TP), as well as visual appearance, current efficiency and codeposition of foreign atoms. Systems reported in the literature (e.g., inorganic salts to increase conductivity or complexing agents to increase polarization) were compared with typical reducing agents normally used in electroless Ni deposition. The mechanism of TP improvement in the case of sodium hypophosphite and dimethylamine-borane has been examined with the electrochemical quartz crystal microbalance (EQCM). Using the EQCM it was shown that there is a synergistic effect between the electrochemical and electroless deposition process. In addition, the activation energy of the latter was determined from temperature dependent measurements.     

Zum Ausscheidungs- und Korrosionsverhalten eines ferritisch-austenitischen Chrom-Nickel-Molybdän-Stahles nach kurzzeitiger Glühbehandlung unter besonderer Berücksichtigung des Schweißens

Structural changes and corrosion behaviour of a ferritic-austenitic chromium-nickel-molybdenum steel after short time heat treatments with special consideration of welding Susceptibility of the ferritic-austenitic steel X 2 CrNiMoN 225 in the solution treated and quenched state to intergranular corrosion and to stress corrosion cracking and pitting corrosion in solutions with chloride ions. Comparison with two austenitic steels (X 5 CrNi 189 and X 3 CrNiMoN 17135). Investigations of the influence of structural changes due to short time isothermal heat treatments and to welding on the mentioned three corrosion types.     

Perturbed dentate gyrus function in serotonin 5-HT2C receptor mutant mice

Serotonin systems have been implicated in the regulation of hippocampal function. Serotonin 5-HT2C receptors are widely expressed throughout the hippocampal formation, and these receptors have been proposed to modulate synaptic plasticity in the visual cortex. To assess the contribution of 5-HT2C receptors to the serotonergic regulation of hippocampal function, mice with a targeted 5-HT2C-receptor gene mutation were examined. An examination of long-term potentiation at each of four principal regions of the hippocampal formation revealed a selective impairment restricted to medial perforant path-dentate gyrus synapses of mutant mice. This deficit was accompanied by abnormal performance in behavioral assays associated with dentate gyrus function. 5-HT2C receptor mutants exhibited abnormal performance in the Morris water maze assay of spatial learning and reduced aversion to a novel environment. These deficits were selective and were not associated with a generalized learning deficit or with an impairment in the discrimination of spatial context. These results indicate that a genetic perturbation of serotonin receptor function can modulate dentate gyrus plasticity and that plasticity in this structure may contribute to neural mechanisms underlying hippocampus-dependent behaviors.