79 research outputs found

    A Description Logic of Typicality for Conceptual Combination

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    We propose a nonmonotonic Description Logic of typicality able to account for the phenomenon of combining prototypical concepts, an open problem in the fields of AI and cognitive modelling. Our logic extends the logic of typicality ALC + TR, based on the notion of rational closure, by inclusions p :: T(C) v D (“we have probability p that typical Cs are Ds”), coming from the distributed semantics of probabilistic Description Logics. Additionally, it embeds a set of cognitive heuristics for concept combination. We show that the complexity of reasoning in our logic is EXPTIME-complete as in ALC

    Comparability of Raman Spectroscopic Configurations: A Large Scale Cross-Laboratory Study

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    This is the final version. Available on open access from the American Chemical Society via the DOI in this recordThe variable configuration of Raman spectroscopic platforms is one of the major obstacles in establishing Raman spectroscopy as a valuable physicochemical method within real-world scenarios such as clinical diagnostics. For such real world applications like diagnostic classification, the models should ideally be usable to predict data from different setups. Whether it is done by training a rugged model with data from many setups or by a primary-replica strategy where models are developed on a 'primary' setup and the test data are generated on 'replicate' setups, this is only possible if the Raman spectra from different setups are consistent, reproducible, and comparable. However, Raman spectra can be highly sensitive to the measurement conditions, and they change from setup to setup even if the same samples are measured. Although increasingly recognized as an issue, the dependence of the Raman spectra on the instrumental configuration is far from being fully understood and great effort is needed to address the resulting spectral variations and to correct for them. To make the severity of the situation clear, we present a round robin experiment investigating the comparability of 35 Raman spectroscopic devices with different configurations in 15 institutes within seven European countries from the COST (European Cooperation in Science and Technology) action Raman4clinics. The experiment was developed in a fashion that allows various instrumental configurations ranging from highly confocal setups to fibre-optic based systems with different excitation wavelengths. We illustrate the spectral variations caused by the instrumental configurations from the perspectives of peak shifts, intensity variations, peak widths, and noise levels. We conclude this contribution with recommendations that may help to improve the inter-laboratory studies.COST (European Cooperation in Science and Technology)Portuguese Foundation for Science and TechnologyNational Research Fund of Luxembourg (FNR)China Scholarship Council (CSC)BOKU Core Facilities Multiscale ImagingDeutsche Forschungsgemeinschaft (DFG, German Research Foundation

    Revealing the identification power of CCS: A novel approach applied to pesticide analysis in food

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    &lt;p&gt;Performing pesticide analysis in food requires coping with multi-class compounds, different matrices and responding rapidly. Screening methods are very useful as they can discriminate samples without any pesticides from those with detectable residues. The laboratory can then focus their efforts on quantitative methods for a smaller number of samples. Different strategies can be applied for screening purposes. Full scan acquisition has however driven most of the attention because of its inherent benefit of theoretical detection of unlimited number of compounds. In spite of this analytical potential, it is well characterized that many factors can influence mass spectra for LC-based methods and given the complexity of the samples analysed, reliable identification can be unreachable in some cases. Ion mobility is known to be a powerful analytical tool for the separation of complex samples and collision cross sections of compounds derived from drift time has been extensively used for characterization purposes. We will present a novel way to use these special mobility features in screening methods from acquisition to data processing. For the assay, UPLC-HDMSE experiments were performed on a Synapt G2-S using a series of standard solutions, spiked matrices and a previous proficiency test. CCS values were generated from the standard solutions and inserted into a scientific library within a new scientific information system. Then, the screening method performances were tested with samples (blank matrices, spiked samples and proficiency test). Based on these results, we will show how we can reliably reduce the number of false positive and more importantly avoid false negative identifications.&lt;/p&gt;</p

    Composition and biological activities of the essential oil of Nigella sativa seeds isolated by accelerated microwave steam distillation with cryogenic grinding

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    In this study, essential oil of Sahara Nigella sativa L. was extracted using a rapid extraction, the microwave steam distillation (MSD) and the cryogenic grinding (CG). Two procedures have been investigated, the MSD1 (seeds inside of oven apparatus) and MSD2 (seeds outside of oven apparatus). Forty-six compounds were identified and significant differences in quantities of the major constituents were observed, mainly were thymoquinone (CLG: 331.82-443.55 mg and CG: 272.95- 413.57 mg/100 g of seeds), p-cymene (CLG: 181.71-244.17 mg, CG: 369.80- 374.40 mg/100 g of seeds), dehydro-sabina ketone (CLG: 24.60- 25.83 mg, GC: 44.02-50.69 mg/100g of seeds), carvacrol (CLG: 10.32-10.96 mg, CG: 3.91-12.67 mg/100 g of seeds) and longifolene (CLG: 11.90- 16.43 mg, CG: 12.72-19.58 mg/100 g of seeds).Results showed that essential oils exhibit a good activity in each antioxidant system with a special attention for β-carotene bleaching test (IC50: 21 to 27 μg/ml) and reducing power (EC50: 9 to 14 μg/ml).The N. Sativa essential oils exhibited higher antibacterial and antifungal activities varying according to technique extraction and grinding mode used, with a high effectiveness against Gram-positive bacteria with a diameter of inhibition zones growth ranging from 9.5 to 35 mm and MIC and MBC values ranging from (0.042–0.10 mg/ml) to (0.20–0.75 mg/ml), respectivel
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