1,720,961 research outputs found
An innovative method based on quick, easy, cheap, effective, rugged, and safe extraction coupled to desorption electrospray ionization-high resolution mass spectrometry for screening the presence of paralytic shellfish toxins in clams
Full text linkThe capabilities of desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS)
were tested for screening the presence of some paralytic shellfish toxins in clams. A quick, easy, cheap,
effective, rugged, and safe (QuEChERS) approach is proposed for sample clean-up.QuEChERS extraction
was optimized by using a full factorial design followed by the multicriteria method of the desirability
functions. Quantitation limits in the microgram pe rkilogram range proved reliability of the method for
the detection of the investigated toxins in accordance to the rules laid down by European legislation. The
optimized QuEChERS-DESI-HRMS based-method allowed for a rapid reliable screening of the in-
vestigated compounds at levels of interest, thus being useful for high-throughput analyse
Rapid desorption electrospray ionization-high resolution mass spectrometry method for the analysis of melamine migration from melamine tableware
No full textMigration of melamine into foods from melamine tableware has been object of recent Rapid Alert System for Food and Feed (RASFF) notifications. In this context, a rapid and sensitive desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS) method was developed and
validated for the determination of melamine migration from plastic materials. The migration test was performed using acetic acid 3% (w/v) as food simulant.
Evaluation of DESI parameters in terms of choice of support, motion profile, geometrical configuration and operating conditions coupled to the use of an orbitrap mass analyzer allowed to achieve significant improvements in terms of selectivity and accuracy obtaining detection and quantitation limits at low microgram per kilogram level. A LC–ESI-MS method was also developed for confirmatory purposes. Both methods were applied to 44 melamine tableware samples available on Italian market in order to assess their compliance with the law. Different concentration levels ranging from 0.0077370.0006 to
3.070.1 mg/kg were found after the third exposure to the simulant in new and used tableware with two samples out of 44 being characterized by a melamine release higher than the legal limit, i.e. 2.5 mg/kg. A two tailed t-test allowed to assess the good agreement between the quantitative results obtained
applying the DESI-MS method with those provided by LC–ESI-MS, thus proving reliability of DESIHRMS as rapid technique for the study of melamine release from plastic materials
Optimization of a rapid QuEChERS sample treatment method for HILIC-MS2 analysis of paralytic shellfish poisoning (PSP) toxins in mussels
Full text linkA rapid and simple QuEChERS sample treatment was proposed for the development of a selective hydrophilic interaction liquid chromatography-ESI-MS2-based method for the determination of saxitoxins (STXs) in mussel samples. Among different sorbents, ABS Elut-NEXUS phase, composed of polystyrene cross-linked with 50 % divinyl benzene and poly(methyl methacrylate), provided the best results. The effects of experimental parameters, including sorbent amount, vortexing time and centrifugation time were investigated and optimized by experimental design. In particular, regression models and desirability functions were applied to find the experimental conditions providing the highest global extraction response. The method was validated under the optimized conditions; detection and quantification limits in the 3-159 μg/kg and 7-436 μg/kg ranges respectively were obtained, except for C2 for which highest values were calculated due to its low ESI ionization efficiency. Finally, the analysis of twenty-eight mussel samples permitted to detect and quantify some of the investigated STXs, proving the applicability of the devised method
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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