1,721,012 research outputs found
Biosintesi e controllo delle micotossine negli alimenti
No full textMycotoxins are harmful secondary metabolites produced by several widespread environment-contaminating fungi mainly belonging to Fusarium, Aspergillus and Penicillium genera. These compounds can be mutagenic, teratogenic and carcinogenic for animals and humans. In our diet we experience a quite harmful daily consumption of mycotoxin-contaminated foods. But why fungi do produce toxins? And how are their biosynthesis regulated? Some mycotoxins have a clear-cut role in the assessment of pathogenesis, i.e. fumonisins and some trichothecene, in the competition with other organisms, i.e. patulin vs bacteria. In other cases, such as aflatoxins, more than one role can be hypothesised. Several are the inputs able to modulate mycotoxin synthesis. Here we have focused our attention on those whose regulatory mechanisms have been assessed. In particular, some of these pathways seem to have a common factor which is represented by the control exerted by the reactive oxygen species. In fact, when a fungus receives an external stimulus reacts by activating, through a quite well-defined signal cascade, an evident switch in its lifestyle. This profound change also lead to the activation of global gene regulators and, in particular, of transcription factors able to enhance the mycotoxin gene cluster expression.
The control exerted by oxidative stress onto the mycotoxin synthesis has lead to use antioxidants of different origin for blocking the synthesis of these harmful compounds both in the field and in the storage. Recently, many natural-based antioxidant or biocontrol-related strategies have been assessed as environment-friendly approaches for controlling the production of many mycotoxins in feed and foodstuffs
Impiego del resveratrolo per il controllo della crescita fungina e della produzione di micotossine su grano e mais
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Effect of different antifungals on the control of paper biodeterioration caused by fungi
No full textThe inhibition of some fungal strains responsible for paper biodeterioration is reported. Antimicrobials (butylated hydroxytoluene, BHT and butylated hydroxyanisole, BHA), azole antifungals (econazole, miconazole and ketoconazole) and chitin synthase inhibitors (uridine, 5-fluorouridine, 2-deoxyuridine) have been assessed for efficacy against Penicillium chrysogenum Thom, Aspergillus terreus Thom, Stachybotrys atra Corda and Chaetomium elatum Kunze, fungal strains isolated from deteriorated papers. Our results have shown that the most evident inhibiting effect on fungal growth has been obtained with miconazole and econazole at 10−3 M
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
Effect of antifungal compounds on both fungal growth and aflatoxin biosynthesis by Aspergillus parasiticus.
No full textDispelling 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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