1,721,029 research outputs found
Differentiation of Vitis vinifera L. and hybrid red grapes by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry analysis of berry skin anthocyanins
No full textAmong the methods that have been developed for anthocyanin characterization, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) offers several analytical advantages in terms of speed, minimal sample handling, specificity, and reliability, without requiring any previous chromatographic separation. This study used MALDI-TOF MS to profile the anthocyanins from the berry skins of 23 red grape varieties clustered as (i) authentic Vitis vinifera grapes, (ii) American hybrid cultivars, and (iii) Casavecchia cultivars, previously characterized as functional crosses of V. vinifera with nondefined hybrid grapevines. Anthocyanin profiling demonstrated evidence of several varietal traits that enabled the differentiation of authentic V. vinifera from hybrid cultivars on a molecular basis. In particular, acyl 3,5-O-diglucoside anthocyanins were established as easily monitored molecular markers of the hybrid varieties. It was also demonstrated that MALDI-post source decay MS is a powerful tool to differentiate isobaric 3,5-O-diglucosides and their derivatives, which prevail in hybrid cultivars, from acylated 3-O-glucoside anthocyanins
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
Proteomic approaches to study structure, functions and toxicity of legume seeds lectins. Perspectives for the assessment of food quality and safety
No full textLectins are a structurally diverse class of (glyco)proteins which bind mono- and oligosaccharides with high specificity and in a reversible way. For many years, the unique sugar binding properties of plant lectins have been exploited for the development of biochemical tools for glycoprotein isolation and characterisation, and the use of lectins as a glycoprofiling tool has became much more sophisticated with the advent of lectin microarrays, in which a panel of lectins are immobilized on a single chip for glycomic analysis. Among the numerous lectins studied so far, those from legumes represent the largest family. They can be present at relatively high amounts depending on genetic as well as environmental factors, and are accumulated especially in the seeds. For this reason, some lectins as the phytohemagglutinin from the common bean Phaseolus vulgaris constitute a possible risk, since consumption of raw or incorrectly processed beans has been shown to cause outbreaks of gastroenteritis, nausea and diarrhoea. On the other hand, for these anti-nutritional properties, bean extracts enriched in lectins or in lectin-related amylase inhibitors are also finding a growing use as active ingredients of "weight-blockers" in dietetic preparations for obesity treatment. Current methods to determine the lectin levels in foods are based on immunoenzymatic or toxicity tests, which are largely aspecific. Very recently, the availability of proteomic methodologies has allowed to start development and validation of sensitive and specific assays for detecting trace amounts of harmful lectins in either raw or processed foods. In this review, the main aspects of current and perspective applications of mass spectrometry and proteomic technologies to the structural characterisation of legumes are presented, with focus on issues related to detection, identification, and quantification of phytohemagglutinins relevant for their biochemical, immunological and toxicological aspect
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
Adapting avalilable ELISA assays for gliadin to the assessment of gluten content in complex matrixes
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