Geographic characterization of Greek wine by inductively coupled plasma–mass spectrometry macroelemental analysis

Abstract

Studying wine mineral profile has been proven as a valuable tool in geographical origin discrimination and authenticity for both producers and consumers. Adulteration of wines, in terms of geographical origin or variety, is considered a major topic of extensive research. Traceability and authenticity of wines have been previously studied on the basis of typical mineral element patterns by means of chemometric methods. In this context, analytical methods were developed for the determination of mineral elements in wines by inductively coupled plasma–mass spectrometry. This study aimed at classifying selected varietal Greek wines from various regions by employing instrumental analysis. Preliminary data of wine mineral content enabled for the classification of samples according to geographical origin and variety. However, further work is required in order to draw more valid conclusions and to obtain a detailed map of the mineral element content of Greek wines according to their geographical origin and/or variety.     

Is There a Place in OR for Intelligent Tutoring Systems?

Intelligent tutoring systems (ITS) have recently found a wide range of potential applications across a multitude of disciplines and subject areas. This paper investigates the suitability and feasibility of developing ITS in the general context of OR as well as in a specific OR activity, simulation. It also examines how a current teaching aid for simulation model debugging can be transformed into an ITS and proposes a specification for the transformation process. The paper concludes that ITS could be useful in OR either for use as prime training systems or integrated in existing OR teaching packages. However, the field of ITS is in its infancy and development efforts are likely to be labour-intensive.     

Synthesis of amphoteric polystyrene particles using mixed initiators

The synthesis of amphoteric polystyrene latex particles, using a mixture of cationic (amidinium based) and anionic (carboxylic acid based) initiators in a surfactant-free emulsion polymerization reaction is investigated; this extends work described in an earlier paper by Bolt et al. Electrophoretic mobility measurements show the effect of the initiator concentration ratio on the isoelectric point (IEP) of the particles. A good correlation with theoretical predictions is obtained. Particle size and polydispersity are determined as a function of the lag time between the addition of each initiator. An increase in particle size and polydispersity is observed at short lag times. It is shown that this is due to the ratio of the cationic to anionic surface charge approaching unity during the reaction. At long lag times an increase in polydispersity may occur due to late-stage, secondary nucleation upon addition of the second initiator. Increasing the reaction pH to reduce the degree of ionization of the cationic initiator greatly reduces the polydispersity and has a significant effect on the IEP of the particles. This effect is ascribed to the burial of a fraction of the neutral amidine groups below the particle surface due to their increased solubility in the monomer. Slow addition of the second initiator was found to reduce the polydispersity of the particles, while maintaining an IEP value consistent with that expected for the ratio of initiators added.     

The Efficiency of RP-TLC for Lipophilicity Assessment. A Comparative Study on a Series of Pyrrolyl-Acetic Acid Derivatives,Inhibitors of Aldose Reductase

JPC – Journal of Planar Chromatography – Modern TLC - The lipophilicity of a series of pyrrolyl-acetic acid derivatives, inhibitors of the aldose reductase enzyme, was assessed by...