1,720,965 research outputs found
Simultaneous determination and dietary risk assessment of clethodim and its metabolites in different fruits and vegetables
No full textClethodim is one of the most widely used herbicides in agriculture and, after field application, is metabolised to several metabolites. The potential toxicological negative effects of these compounds are poorly understood. Thus, recently, within the risk assessment framework, the European Food Safety Authority (EFSA) proposed to include the minor metabolites in the definition of clethodim residue. In this work, an easy to use and reliable UHPLC method coupled with a triple quadrupole MS/MS was developed and validated for the detection and quantification of the herbicide clethodim and related metabolites clethodim sulphone, clethodim sulphoxide, metabolites M17R and M18R in apple, grape, olive and rice. The five analytes were extracted by using a modified QuEChERS procedure, while the active ingredients were determined in multiple reaction monitoring (MRM) ion-switching mode. The proposed method showed calibration curve linearity with r2≥0.990 for all active ingredients (a.is.) both in solvent and matrix extracts. Limits of quantitation (LOQ) of the five compounds ranged from 9.44g/kg for M17R in olive extract to 11.01g/kg for clethodim in apple extract. Recoveries values ranged from 86% to 119% at two concentration levels (LOQ and 10xLOQ), while the intraday and interday precisions of the method were both below 10% in all cases. The method was successfully used for the quantification of the five a.is. in different food matrices. Furthermore, chronic dietary risk was investigated using a hazard quotients (HQ) method based on European dietary habits. The chronic dietary exposure risk quotients ranged from 1.0*10-5 (lower bound scenario) to 2.7*10-4 (upper bound scenario) which were significantly lower than 1. Data obtained indicate that the dietary exposure risks were acceptable for clethodim and its major and minor metabolites applied in apple, table grape, rice and table olive
Occurrence of acrylamide, hydroxymethylfurfural and furaldehyde as process contaminants in traditional breakfast cereals: “Bsissa”
No full textHydroxymethylfurfural (HMF), furaldehyde (FAL) and acrylamide (AA) are produced during the food roasting
process. The content of these toxic products in a common ready-to-eat breakfast, known as “Bsissa”, was
investigated. This North African traditional food is mainly based on roasted cereals, leguminous and spices. In
the present study, thirty-four commercial “Bsissa” have been investigated for their toxic HMF, FAL and AA
content using RP-HPLC-DAD. Additionally, to distinguish the main way of the production of these toxic products
(Maillard reaction or caramelization origin), total protein, carbohydrates and reducing sugar were quantified and
found in the range 5.63–25.72 g, 45.75–84.33 g and 0.37–3.74 g per 100 g of Bsissa, respectively. This result
makes it also suitable to cover daily needs as a breakfast food. Obtained results showed that HMF and FAL were
detected in most samples, with values not exceeding 24.71 mg/100 g and to 3.91 mg/100 g, respectively. AA was
not detected in all the studied samples. Principal components (PC) and hierarchical classification were employed
to establish the samples’ heat damage based on relations between variables. Two PCs were obtained which
explain more than 75% of the total variance, thus grouping the Bsissa in two clusters based on the main used
cereal. This analysis may help in the mitigation step of furanic compounds by choosing the appropriate Bsissa
ingredients
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Computational and experimental approaches to probe GPCR activation and signaling
No full textG protein-coupled receptors (GPCRs) regulate different physiological functions, e.g., sensation, growth, digestion, reproductivity, nervous and immune systems response, and many others. In eukaryotes, they are also responsible for intercellular communication in response to pathogens. The major primary messengers binding to these cell-surface receptors constitute small-molecule or peptide hormones and neurotransmitters, nucleotides, lipids as well as small proteins. The simplicity of the way how GPCR signaling can be regulated by their endogenous agonists prompted the usage of GPCRs as major drug targets in modern pharmacology. Drugs targeting GPCRs inhibit pathological processes at the very beginning. This enables to significantly reduce the occurrence of morphological changes caused by diseases. Until recently, X-ray crystallography was the method of the first choice to obtain high-resolution structural information about GPCRs. Following X-ray crystallography, cryo-EM gained attention in GPCR studies as a quick and low-cost alternative. FRET microscopy is also widely used for GPCRs in the analysis of protein-protein interactions (PPIs) in intact cells as well as for screening purposes. Regarding computational methods, molecular dynamics (MD) for many years has proven its usefulness in studying the GPCR activation. MODELLER and Rosetta were widely used to generate preliminary homology models of GPCRs for MD simulation systems. Apart from the conventional all-atom approach with explicitly defined solvent, also other techniques have been applied to GPCRs, e.g., MARTINI or hybrid methods involving the coarse-grained representation, less demanding regarding computational resources, and thus offering much larger simulation timescales
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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