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A simple and rapid capillary electrophoretic method with UV detection (CE-UV) has been developed for the identification of five natural dyes namely, carmine, indigo, saffron, gamboge and Rubia tinctoria root. The separation was performed in a fused-silica capillary of 64.5 cm length and 50 microm id. The running buffer was 40 mM sodium tetraborate buffer solution (pH 9.25). The applied potential was 30 kV, the temperature was 25 degrees C and detections were performed at 196, 232, 252, 300 and 356 nm. The injections were under pressure of 50 mbar during 13 s. The method was applied to the identification of carminic acid, gambogic acid, crocetin, indigotin, alizarin and purpurin in the collection of drawings and maps at the Royal Chancellery Archives in Granada (Spain). The method was validated by using HPLC as a reference method.

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The insular cortex has been related to various sensory, regulatory, and learning processes, which frequently include affective-emotional components. The objective of this study was to investigate the possibility of inducing reinforcing effects by electrical stimulation of this cortical region in Wistar rats. Concurrent conditioned place preference tasks were conducted for this purpose, using two rectangular mazes that differed in dimensions, texture, and spatial orientation. A significant correlation was found in the preferences induced by insular cortex electrical stimulation between the two mazes. Animals showed consistent preference or avoidance behaviors associated with simultaneous insular cortex stimulation. No electrical self-stimulation was achieved. In a second experiment, animals that showed consistent place preference after the simultaneous insular cortex electrical stimulation were administered with 4 mg/ml/kg of naloxone. The results revealed that this opiate antagonist blocked concurrent place preference learning when the task was conducted in a new maze but not when it was conducted in the same maze as that in which the animals had learned the task. These results are discussed in terms of the participation of the insular cortex in various reward and aversion modalities.

This study examined the stimulus specificity of external lateral parabrachial (LPBe) rewarding stimulation by using two identical learning procedures that may dissociate conditioned reinforcement to either the place or the flavor stimulus. Animals were presented with two distinct flavors in two different positions (left and right) that were varied throughout the experimental sessions. In the first experiment, LPBe stimulation was associated with one or other flavor, while in the second it was conditioned to one or other place in which these flavors were offered. The results show that, despite stimulus interferences, the animals develop specific conditioned preferences for the flavor stimuli (experiment 2A), and also for the place of their presentation (experiment 2B). These data are discussed in the context of brain reward systems and the biological constraints that characterize some learning modalities.

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The inks used in Arabic manuscripts written between the 11th and 17th centuries and belonging to the archive of the Sacromonte Abbey in Granada, Spain, were studied. The constituent materials were determined with DRX, SEM/EDX, FTIR, HPLC and EC analytical methods. The results obtained coincide with the components described in a considerable number of Islamic recipes and treatises from the period. In all cases gum arabic was identifi ed as the binding agent. Iron gall inks and carbon blacks were used for black inks. Vermillion and minium were the most used for red inks; verdigris, malachite and lead and tin yellows for green inks; natural ultramarine blue (lapis lazuli), azurite and smalte in blue inks; and, fi nally, gold and some silver for gold inks. Chlorine was detected in a large number of the samples for reasons that cannot be fully explained. Calcium and magnesium were present, presumably as in their carbonate form, as an additive in the pulp.Zusammenfassung/résumée at end of article