Compositional models and conditional independence in evidence theory

The goal of the paper is twofold. The first is to show that some of the ideas for representation of multidimensional distributions in probability and possibility theories can be transferred into evidence theory. Namely, we show that multidimensional basic assignments can be rather efficiently represented in a form of so-called compositional models. These models are based on the iterative application of the operator of composition, whose definition for basic assignments as well as its properties are presented. We also prove that the operator of composition in evidence theory is in a sense generalization of its probabilistic counterpart.The second goal of the paper is to introduce a new definition of conditional independence in evidence theory and to show in what sense it is superior to that formerly introduced by other authors.     

Ordinally equivalent data: A measurement-theoretic look at formal concept analysis of fuzzy attributes

We show that if two fuzzy relations, representing data tables with graded attributes, are ordinally equivalent then their concept lattices with respect to the Gödel operations on chains are (almost) isomorphic and that the assumption of Gödel operations is essential. We argue that measurement-theoretic results like this one are important for pragmatic reasons in relational data modeling and outline issues for future research.     

Local computations in Dempster–Shafer theory of evidence

When applying any technique of multidimensional models to problems of practice, one always has to cope with two problems: the necessity to represent the models with a ”reasonable” number of parameters and to have sufficiently efficient computational procedures at one’s disposal. When considering graphical Markov models in probability theory, both of these conditions are fulfilled; various computational procedures for decomposable models are based on the ideas of local computations, whose theoretical foundations were laid by Lauritzen and Spiegelhalter.The presented contribution studies a possibility of transferring these ideas from probability theory into Dempster-Shafer theory of evidence. The paper recalls decomposable models, discusses connection of the model structure with the corresponding system of conditional independence relations, and shows that under special additional conditions, one can locally compute specific basic assignments which can be considered to be conditional.     

Enantiomerically enriched trans-diols from alkenes in one pot: a multicatalyst approach

Multicatalysts consisting of non-natural oligopeptides with distinctly different catalytic moieties create molecular complexity in a multistep one-pot sequence starting from simple alkenes yielding highly enantiomerically enriched trans-diols.     

A nonradioactive electrophoretic mobility shift assay for measurement of pregnane X receptor binding activity to CYP3A4 response element

The electrophoretic mobility shift assay (EMSA) is a method for the study of specific DNA–protein interactions in vitro. The pregnane X receptor (PRX) is a key xenobiotic sensor that regulates the expression of drug‐metabolizing enzymes and many other genes. Radiolabeled ³²P‐DNA‐probes had been used in studies of PXR‐DNA interactions. There is an increasing need for nonradioactive assays, due to the health, safety and environmental issues. In the current study, we present a protocol for the nonradioactive electrophoretic mobility shift assay, allowing studying interactions between human PXR with promoter DNA sequences.     

Enantioseparation of tartaric acid by ligand‐exchange capillary electrophoresis using contactless conductivity detection

A method for the determination of tartaric acid enantiomers using CE with contactless conductivity detection has been developed. Cu(II) as a central metal ion together with l ‐hydroxyproline were used as a chiral selector, the BGE was composed of 7 mM CuCl_2, 14 mM trans‐4‐hydroxy‐l ‐proline, and 100 mM ε‐aminocaproic acid; the pH was adjusted to 5 by hydrochloric acid. Separation with a resolution of 1.9 was achieved in 9 min in a polyacrylamide‐coated capillary to suppress the EOF. Various counterions of the BGE were studied, and migration order reversal was achieved when switching from ε‐aminocaproic acid to l ‐histidine. With detection limits of about 20 μM, the method was applied to the analysis of wine and grape samples; only l ‐tartaric acid was found.     

C6‐substituted purine derivatives: an experimental and theoretical 1H, 13C and 15N NMR study

We measured the ¹H, ¹³ C and ¹⁵ N chemical shifts for a series of purine derivatives bearing a norbornane substituent in position 9 and various substituents in position 6. The experimental data were complemented with density functional theory (DFT) calculations. The comparison of the calculated and experimental chemical shifts provided us with information about the tautomer and conformational equilibria of the studied compounds. Copyright © 2012 John Wiley & Sons, Ltd.     

RP-ZrO2 Stationary Phase as an Alternative to Separate of Doxazosin Impurities

Degradation products and related compounds occurring in drugs as impurities have often very similar properties as the parent substance. Therefore new analytical separation methods which show appropriate selectivity are required. Apart from improvements on silica-based reversed phases the attention has also been focused on other materials such as modified inorganic supports. In this study a polystyrene-coated zirconia was examined as an alternative in analysis of parent drug (doxazosin) and its impurities. Doxazosin and its five pharmacopoeial impurities were separated within 16 min. The suitability of the developed method was verified and confirmed by means of linearity, precision, inter-day precision, robustness and determination of LOD as well as LOQ. The results proved the potential of zirconia-based stationary phases to be useful alternatives in the field of drug analysis.