240 research outputs found

    Developmental parallelism in primates

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    The authors examined a large random sample of skulls from two species of macaques: rhesus monkeys and cynomolgus monkeys. The skulls were measured, divided into age and sex groups and thoroughly analysed using statistical methods. The analysis shows that skulls of young rhesuses are considerably more domed, i.e. have better-developed neurocrania, than their adult counterparts. Male and female skulls, on the other hand, were found to be very similar, which means that sexual dimorphism of the rhesus macaque was suppressed. Both of these patterns are known from the human evolutionary pattern. No such parallelism to the development of Homo sapiens was found in the cynomolgus monkeys. The authors conclude that mosaic hominisation trends may have featured in the evolution of all primates. This would mean that apes were not a necessary step on the evolutionary way leading to the development of Homo sapiens, who may have started to evolve at an earlier stage of monkeys

    Application of SPE for selective fractionation of essential oils constituents from plant materials

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    Solid-phase extraction (SPE) is simple and inexpensive sample preparation procedure which can be applied for the isolation/fractionation of essential oil compounds from wide variety of samples, such as foodstuffs, biological and environmental. Due to the complex nature of the examined matrices and frequently low concentration level of target components, analytical procedures require the use of initial sample preparation stage. The paper shows the possibility of essential oil components fractionation from different plant materials using SPE method. The results presented in this paper shows that the proposed SPE procedure allows for easy and total fractionation of essential oil constituents (especially low-molecular oxygen compounds) from the sample matrix

    Isomerization of bitter acids during the brewing process

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    Beer is the world's oldest and most widely consumed alcoholic beverage. The transformation of bitter acids to iso-α and iso-ß-acids is recognized as the key step of beer production. The paper shows and discusses the transformation kinetics of α- and ß-acids into their iso-form. Following the performed experiments, the largest amounts of the bitter acids isomers are formed in the brewing process carried out at 80oC for more than 100 minutes. The presented data are in good agreements with the knowledge of experienced brewers who learned about the brewing process relying on sensory tests

    A simplified protocol for detecting two systemic bait markers (Rhodamine B and iophenoxic acid) in small mammals

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    We developed a method of quantifying levels of fluorescence in the whiskers of wild stoats (Mustela erminea) using fluorescence microscopy and Axiovision 3.0.6.1 software. The method allows for discrimination between natural fluorescence present in or on a whisker, and the fluorescence resulting from the ingestion of the systemic marker Rhodamine B (RB), although some visual judgement is still required. We also developed a new high performance liquid chromatography (HPLC) protocol for detecting the systemic marker iophenoxic acid (IPA) in the blood of laboratory rats (Rattus norvegicus) and wild stoats. With this method, the blood of an animal that has consumed IPA can be tested for the presence of the foreign IPA compound itself. This is a more reliable test than the previous method, which measured the raised level of natural blood protein-bound iodine correlated with IPA absorption. The quantity of blood required from animal subjects is very small (10 μl), so the testing is less intrusive and the method can be extended to smaller species. The extraction technique uses methanol, rather than acids and heavy metal salts, thereby simplifying the procedure. Recovery of IPA is quantitative, giving a highly reliable reading. In experiments on captive rats the IPA method proved successful. Of 12 positively marked carcasses, two that had not been frozen for the 24 h before blood samples were taken showed relatively lower IPA levels. The same IPA detection method, as well as the whisker analysis for RB, was applied successfully to a population of wild stoats to which both Rhodamine B and IPA were made available at bait stations. The presence of both bait markers was detectable in rats for at least 21 days and in stoats for at least 27 days
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