1,720,958 research outputs found
Automated sample preparation and analysis by gas chromatography tandem mass spectrometry (GC–MS/MS) for the determination of 3- and 2-monochloropropanediol (MCPD) esters and glycidol esters in edible oils
No full textThe potentially carcinogenic process contaminant 3- and 2-monochloropropanediol esters (2-MCPD and 3-MCPD esters) and glycidyl esters (GEs) are under study in refined oils and foodstuffs. Legislation set recommended total daily intake (TDI) for 3-MCPD of 0.8 μg/kg and as low as reasonably achievable (ALARA) for glycidol. Usually, the so far adopted method for the determination of these contaminants relay on numerous and time-consuming steps for sample preparation (AOCS methods) and on GC–MS detection. The obtained sensitivities and the number of processable samples are thus limited. In this optic, new reliable methods that allow for the fast and sensitive determination of these contaminants in edible oils may be considered an improvement of the overall strategy of tackling the problem. In this paper a new automated method for sample preparation and detection by GC–MS/MS is presented and validated. Data on sensitivity (LOD at 1.5, 2.2 and 3 ng/g for 3-MCPD, 2-MCPD, 3-MBPD (deriving from glycidol), respectively), linearity across low and high calibration ranges and precision showed to be fit-for-purposes. Finally, the methodology was applied to ten extra virgin oil samples and one sample of sunflower seeds oil
Per- and polyfluoroalkyl substances (PFAS) determination in shellfish by liquid chromatography coupled to accurate mass spectrometry
No full textPer- and polyfluoroalkyl substances (PFAS) are a numerous class of
chemical compounds characterized by a C-F backbone of variable
length with either a sulfonic acid group (PFSA) or a carboxylic acid
(PFCA), produced for more than 70 years at industrial level.1 PFOS
and PFOA are the predominantly cited molecules of this class. Cur-
rently, these compounds are debated both at scientific and political
levels due to the risks associated to exposure to legacy (PFOA, PFOS,
etc.) and to emerging perfluorinated compounds (HFPO-DA or GenX,
ADONA, C6O4), introduced after the banning in the production/
import/use of PFOA and PFOS.2,3
Per- and polyfluoroalkyl substances (PFAS) presence in food: Comparison among fresh, frozen and ready-to-eat vegetables
Full text linkThere is a worldwide discussion to provide safety limits in food for per-and polyfluoroalkyl substances (PFAS), a group of persistent contaminants associated to human disease. Processed food is more at risk of containing increased amounts of PFAS as a consequence of intentionally or non-intentionally contamination during manipulation and packaging. Among food products, also vegetables can be submitted to industrial manipulation; therefore, a different PFAS content correlated to the level of vegetables processing is conceivable. This study assessed the amount and type of PFAS present in fresh, frozen and ready-to-eat vegetables. Differences have been observed between the three groups of samples in the average PFAS content; the difference between ready-to eat and frozen vegetables resulted statistically significative. Organic vegetables displayed a lower total amount of PFAS respect to the traditional counterpart. The impact of industrial manipulation remains to be cleared, but pesticides use during cultivation could be considered a source of PFAS contamination
Multiple prohibited ingredients detected in nutritional supplements in a case of adverse analytical finding (AAF)
No full textDoping itself is considered by most athletes as “dishonest, unhealthy, and/or risky because of sanctions”; however, the attitude on performance-enhancing substances (PES) is more tolerant. Dietary supplement consumption in sport is considered by the athletes as advisable for improving recovery ability (66%), improving muscle performance (22%), enhancing the immune system (40%), and also to protect health (45%). However, data collected by some authors display those supplements that are often used without full understanding or evaluation of the potential benefits and risks associated with their use and without consultation with sports nutrition professionals.1 Dietary supplement market worldwide is estimated for 2022 at USD 155.2 billion and projected to reach USD 220.8 billion by 2027. Among the consumers, athletes play a major role. Between 40% and 100% of athletes typically use supplements, depending on the type of sport, level of competition, and the definition of supplements. However, supplementation may not improve performance and may have a detrimental effect on both performance and health. Dietary supplements are classified as a subcategory of food, so manufacturers are not required to provide evidence of product safety and efficacy nor obtain approval from regulatory bodi
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
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