Radicals of rings and pullbacks

AbstractGeneralizing various concrete radicals in associative rings like the nilradical, the Jacobson radical, and so on, A.G. Kurosh and S.A. Amitsur introduced an abstract notion of radical in the early 1950s. The basic notions of their general radical theory can be characterized by properties which are “almost” categorical – in the sense that they can be conveniently defined in the category of rings or even in suitable categories of Ω-groups but not in general categories. Here we are going to characterize radicals of associative rings by means of pullbacks, a notion which is of a purely categorical nature. Throughout the paper we shall work in the category C of associative rings (not necessarily with identity), just calling them “rings”. We hope that our two categorical characterizations of semisimple classes in C can provide natural general frameworks for radical theory, just as localizations do for torsion theories

A simplicial approach to factorization systems and Kurosh–Amitsur radicals

AbstractRegarding categories as simplicial sets via the nerve functor, we extend the notion of a factorization system from morphisms in a category, to 1-simplexes in an arbitrary simplicial set. Applied to what we call the simplicial set of short exact sequences, it gives the notion of Kurosh–Amitsur radical. That is, we present a unified approach to factorization systems and radicals

Enrichment of pineapple aroma compounds from model solutions by sweeping-gas and vacuum-pervaporation

Our experiments were based on a model solution containing five of the main pineapple aroma components. Both sweeping-gas pervaporation and vacuum-pervaporation methods were carried out. Measurements were performed at different temperatures and feed flow rates. The purposes of this study were to examine applicability of the two pervaporation methods in reference to the pineapple aroma recovery, the effects of the operating parameters on the process, and modelling the pervaporation process by resistance-in-series model. Higher enrichment could be reached with vacuum-pervaporation than the sweeping-gas method. The separation process is determined by the diffusion of compounds in the membrane, thus the resistance in the boundary layer at liquid side is negligible. Based on performed experiments, the pervaporation process can be applied in beverage industry for aroma recovery

Reference materials (RMs) for analysis of the human factor II (prothrombin) gene G20210A mutation

The Scientific Committee of Molecular Biology Techniques (C-MBT) in Clinical Chemistry of the IFCC has initiated a joint project in co-operation with the European Commission, Joint Research Centre, Institute of Reference Materials and Measurements to develop and produce plasmid-type reference materials (RMs) for the analysis of the human prothrombin gene G20210A mutation. Although DNA tests have a high impact on clinical decision-making and the number of tests performed in diagnostic laboratories is high, issues of quality and quality assurance exist, and currently only a few RMs for clinical genetic testing are available. A gene fragment chosen was produced that spans all primer annealing sites published to date. Both the wild-type and mutant alleles of this gene fragment were cloned into a pUC18 plasmid and two plasmid RMs were produced. In addition, a mixture of both plasmids was produced to mimic the heterozygous genotype. The present study describes the performance of these reference materials in a commutability study, in which they were tested by nine different methods in 13 expert laboratories. This series of plasmid RMs are, to the best of our knowledge, the first plasmid-type clinical genetic RMs introduced worldwid