Development of a simple gel permeation clean-up procedure coupled to a rapid disequilibrium enzyme-linked immunosorbent assay (ELISA) for the detection of Sudan I dye in spices and sauces

Sudan dyes have been found to be added to chilli and chilli products for illegal colour enhancement purposes. Due to the possible carcinogenic effect, they are not authorized to be used in food in the European Union or the USA. However, over the last few years, many products imported from Asian and African countries have been reported via the Rapid Alert System for Food and Feed in the European Union to be contaminated with these dyes. In order to provide fast screening method for the detection of Sudan I (SI), which is the most widely abused member of Sudan dyes family, a unique (20 min without sample preparation) direct disequilibrium enzyme-linked immunosorbent assay (ELISA) was developed. The assay was based on polyclonal antibodies highly specific to SI. A novel, simple gel permeation chromatography clean-up method was developed to purify extracts from matrices containing high amounts of fat and natural pigments, without the need for a large dilution of the sample. The assay was validated according to the Commission Decision 2002/657/EC criteria. The detection capability was determined to be 15 ng g⁻¹ in sauces and 50 ng g⁻¹ in spices. The recoveries found ranged from 81% to 116% and inter- and intra-assay coefficients of variation from 6% to 20%. The assay was used to screen a range of products (85 samples) collected from different retail sources within and outside the European Union. Three samples were found to contain high amounts (1,649, 722 and 1,461 ng g⁻¹) of SI by ELISA. These results were confirmed by liquid chromatography-tandem mass spectrometry method. The innovative procedure allows for the fast, sensitive and high throughput screening of different foodstuffs for the presence of the illegal colorant SI.     

Retention mechanism divergence of a mixed mode stationary phase for high performance liquid chromatography

Mixed mode stationary phases utilize secondary retention mechanisms to add a dimensionality to the surface of high performance liquid chromatography (HPLC) adsorbents. This approach was used by several authors to improve the separation performance of single dimension separations. We explored the magnitude of these secondary interactions by performing an off-line two-dimensional (2D)-HPLC separation with a Scherzo SM-C18 column of a β-lactoglobulin tryptic digest with a mobile phase pH of 7 in the first dimension and 2 in the second. Mechanism divergence was determined using the peak capacity and a geometric approach to factor analysis, to measure the correlation. This separation was repeated with a C18 stationary phase as a control. It was found that the C18 column had a correlation coefficient of 0.784, smaller than the mixed mode column, 0.884. This indicated that the retention mechanisms of the C18 column were more divergent under these two pH environments than the mixed mode column. However, the SM-C18 still provided alternative selectivity of the peptides to that of the C18 and could be considered as a good alternative for further 2D-HPLC separations.     

Die Bestimmung von Cumarin und Melilots?ure

Ohne Zusammenfassung     

Untersuchung von Wasser

Ohne Zusammenfassung     

Description of an individual patient methodology for calculating the cost-effectiveness of treatments for osteoporosis in women

Models of the cost-effectiveness of pharmaceutical interventions for the treatment of osteoporosis have traditionally adopted cohort-based approaches. We present a transition-state model to simulate the experience of individual patients, allowing the full patient history and residential status to influence the probabilities of future fractures at the hip, spine, wrist or proximal humerus. Alongside epidemiological data, we used systematic literature reviews of costs, utilities and efficacy to populate the model for a UK setting. We established a statistical relationship between the inputs and outputs of the individual patient model creating a near instantaneous emulation of the individual patient model. We undertook extensive sensitivity analyses to analyse the uncertainty in the estimated incremental cost per quality-adjusted life year due to uncertainty in the efficacy of the drugs. We provide illustrative results accompanied by individual and multi-interventional cost-effectiveness acceptability curves.     

On a generalised Connes-Hochschild-Kostant-Rosenberg theorem

The central result of this paper is an explicit computation of the Hochschild and cyclic homologies of a natural smooth subalgebra of stable continuous trace algebras having smooth manifolds X as their spectrum. More precisely, the Hochschild homology is identified with the space of differential forms on X, and the periodic cyclic homology with the twisted de Rham cohomology of X, thereby generalising some fundamental results of Connes and Hochschild-Kostant-Rosenberg. The Connes-Chern character is also identified here with the twisted Chern character.     

Optimality of a Standard Adaptive Finite Element Method

In this paper an adaptive finite element method is constructed for solving elliptic equations that has optimal computational complexity. Whenever, for some s > 0, the solution can be approximated within a tolerance ε > 0 in energy norm by a continuous piecewise linear function on some partition with O(ε^-1/s) triangles, and one knows how to approximate the right-hand side in the dual norm with the same rate with piecewise constants, then the adaptive method produces approximations that converge with this rate, taking a number of operations that is of the order of the number of triangles in the output partition. The method is similar in spirit to that from by Morin, Nochetto, and Siebert, and so in particular it does not rely on a recurrent coarsening of the partitions. Although the Poisson equation in two dimensions with piecewise linear approximation is considered, the results generalize in several respects.