1,720,963 research outputs found
Photoprotective characteristics of natural antioxidant polyphenols
No full textFourteen natural polyphenols belonging to the classes of stilbenes, flavonoids and hydroxycinnamic acid derivatives, have been investigated in order to verify the combination of their photoprotective characteristics with their antioxidant properties.To this purpose, sun protection factor (SPF), UVA/UVB ratio and critical wavelengths (λc), have been considered to evaluate photoprotection capacity, while inhibition of lipid peroxidation has been adopted as a reliable measure of the antioxidant properties.The results obtained indicate that a large number of these natural phenol derivatives show both antioxidant activity and photoprotective characteristics and, as a consequence, they could be interesting components for pharma-photoprotection formulations. In fact, these compounds associate to a preventive function, linked to UV filtering properties, an effective action, correlated to antioxidant capacity of contrast towards UV-induced ROS injury. © 2014 Elsevier Inc
A Mossbauer study of some coloured marbles (cipollino mandolato, rosso antico and fior di pesco): implications on the nature of their colour.
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Propolis as potential cosmeceutical sunscreen agent for its combined photeprotective and antioxidant properties
No full textPropolis, bee glue, and its main polyphenolic components show high antioxidant activity as found measuring their inhibitory action on lipid peroxidation of linoleic acid (LA) in sodium dodecyl sulfate (SDS) micelles. Furthermore, these substances evidence effectiveness as broad spectrum UVB and UVA photoprotection sunscreens, as it results by measurements of sun protection factor (SPF), the universal indicator related primarily to UVB radiations, and of the two parameters giving an indication of the UVA absorbance properties, i.e. UVA/UVB ratio and critical wavelength. The combination of these characteristics moves up propolis and its main polyphenolic components to the class of cosmeceuticals, as possible active ingredient of sunscreen commercial formulations for their protective and preventive properties.© 2010 Elsevier B.V. All rights reserved
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
Phenolic content and antioxidant properties of fermenting musts and fruit and vegetable fresh juces.
No full textVariations 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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