Ultra-trace analysis of platinum in human tissue samples

Background levels of platinum were determined in human autopsy tissues taken from five individuals. The investigated specimens were lung, liver and kidney. Sample preparation involved microwave digestion followed by an open vessel treatment. Inductively-coupled plasma sector field mass spectrometry (ICP-SFMS) was applied in combination with an ultrasonic nebulization/membrane desolvation system for sample introduction. Isotope dilution analysis was employed for accurate quantification of platinum. Excellent procedural detection limits (3 s validation) of 20, 20 and 34 pg g^–1 dry weight were obtained for lung, liver and kidney tissue, respectively. Due to the lack of appropriate biological reference material, road dust (BCR-723) was used for method validation. Platinum levels ranging between 0.03 and 1.42 ng g^–1 were determined in the investigated samples. The platinum concentrations observed in human lung tissue may reflect the increasing atmospheric background levels of platinum originating from car catalysts. The presence of platinum in kidney and liver tissue samples clearly indicates the bioavailability of the element.     

On Triazoles. XIII. The reaction of 5-benzalimino-1,2,4-triazoles with substituted acetyl chlorides

The reaction of Schiff bases prepared from 1- and 2-substituted-5-amino-1,2,4-triazoles with phenoxyacetyl chlorides in the presence of triethylamine and a mixture of phosphorus oxychloride and dichloroacetic acid in dimethylformamide to yield β-lactam 4 , a dihydro-1,2,4-triazolo[4,3-a]pyrimidine-5(1H)-one 5, a 1,2,4-triazolo[1,5-a]pyrimidin-5(3H)-one 9 and the corresponding 1,2,4-triazolo[4,3-a]pyrimidine-5(1H)-one 10 derivatives was studied.     

A one shot method for divertor target shape optimization

Shape optimization methods, as commonly applied in aerodynamic design applications, have recently been adapted for use in nuclear fusion divertor target design. The resulting algorithms are very efficient compared to the standard use of numerical edge plasma simulations as analysis tools only. In this paper, we highlight some numerical aspects of the underlying algorithm, focusing on a correct, nine-point discretization of the fluxes and the need for an adjoint pressure correction equation. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Fractals and generalized inner products

The generation of fractals by a generalization of the matrix product is described. These matrix products allow visualization of additional structure of the fractals as well as producing fractals of new types.     

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Regression Modeling and File Matching Using Possibly Erroneous Matching Variables

Many analyses require linking records from two databases comprising overlapping sets of individuals. In the absence of unique identifiers, the linkage procedure often involves matching on a set of categorical variables, such as demographics, common to both files. Typically, however, the resulting matches are inexact: some cross-classifications of the matching variables do not generate unique links across files. Further, the variables used for matching can be subject to reporting errors, which introduce additional uncertainty in analyses. We present a Bayesian file matching methodology designed to estimate regression models and match records simultaneously when categorical variables used for matching are subject to errors. The method relies on a hierarchical model that includes (1) the regression of interest involving variables from the two files given a vector indicating the links, (2) a model for the linking vector given the true values of the variables used for matching, (3) a model for reported values of the variables used for matching given their true values, and (4) a model for the true values of the variables used for matching. We describe algorithms for sampling from the posterior distribution of the model. We illustrate the methodology using artificial data and data from education records in the state of North Carolina.     

Ultrasonic attenuation in plasma-sprayed coating materials

Measurements have been made of the attenuation in thin samples of plasma-sprayed molybdenum, nickel aluminide and aluminium coating materials in the frequency range 2.5 to 15 MHz. It has been found that attenuation is dependent on the structure of the coatings and in particular on porosity. Interference effects in such thin samples are shown to be unimportant because of their high attenuations. An analysis of ultrasonic attenuation through thin samples is presented.