1,720,956 research outputs found
Attività antimutagena del limonene e dei suoi metaboliti
No full textIl limonene è un monoterpene ampiamente diffuso in natura e caratterizzato da una spiccata fragranza agrumata, utilizzata in diversi prodotti commerciali. La sostanza è anche oggetto di grande interesse scientifico per le sue proprietà chemiopreventive. Dal punto di vista metabolico, il limonene subisce una serie di biotrasformazioni che portano alla formazione di monoterpeni monociclici ossigenati, tra cui l’alcool perillilico, che possiede proprietà chemioprevetive analoghe a quelle del precursore1. Alcuni studi hanno dimostrato che il limonene, in particolari condizioni di temperatura e pH, va incontro a biotrasformazioni alternative con formazione di α-terpineolo ed 1,8-cineolo; quest’ultimo sembra responsabile del particolare aroma di alcuni vini invecchiati. Nel presente lavoro abbiamo valutato quanto questa via metabolica alternativa possa modificare l’attività biologica del limonene, in particolare in relazione agli effetti antigenotossici ed antiossidanti. A tal fine, i monoterpeni limonene, α-terpineolo e 1,8-cineolo sono stati sottoposti in parallelo a studi di antimutagenesi, mediante il test di Ames, nei ceppi batterici di Salmonella typhimurium TA98 e TA100 ed Escherichia coli WP2uvrA, contro i mutageni noti 2-nitrofluorene (2-NF), 2-aminoantracene (2-AA), sodio azide (SA) e metilmetansulfonato (MMS), sia in assenza che in presenza di un attivatore metabolico esogeno S9. Inoltre, ne è stata valutata l’attività antiossidante, mediante una batteria di test standardizzati, in particolare: DPPH, ABTS, ferro tiocianato e ferrozina. Nelle nostre condizioni sperimentali, sia il limonene che i due metaboliti inducevano effetti antimutageni, sebbene di entità differente. In particolare, l’attività antimutagena dei due metaboliti era minore o uguale al precursore verso i mutageni SA (% di inibizione: limonene, 55%; α-terpineolo, 37%; 1,8 –cineolo, 28%) e MMS (% di inibizione: limonene, 50%; α-terpineolo, 50%; 1,8 –cineolo, 35%), mentre risultava maggiore verso il 2NF (% di inibizione: limone, 39%; α-terpineolo, 41%; 1,8 –cineolo, 50%). Nei riguardi del 2AA, a fronte di una modesta attività del limonene e dell’1,8-cineolo (inibizione < 40%), l’α-terpineolo presentava una spiccata attività antimutagena, riducendo del 77% il numero delle colonie revertenti. L’attività antiossidante era assente nel limonene e nell’1,8 –cineolo, mentre ’α-terpineolo era attivo come chelante degli ioni ferrosi (effetto massimo 91%; EC50 = 0,5 ± 0,01 mM); tale effetto rappresenta un meccanismo antiossidante indiretto, in quanto, bloccando la reazione di Fenton, inibisce la produzione delle specie reattive dell’ossigeno. I risultati ottenuti mostrano che l’attività antimutagena del limonene è presente, sebbene leggermente modificata in termini di potenza, anche nei metaboliti esaminati. Inoltre, per l’α-terpineolo si evidenzia una spiccata attività antimutagena contro il 2AA e un’attività antiossidante non presenti nel precursore metabolico. Considerando che il 2AA è un composto appartenente alla classe delle amine aromatiche, note come cancerogeni ambientali ed alimentari, la presenza di α-terpineolo o suoi precursori metabolici in componenti della dieta, potrebbe essere oggetto di potenziale interesse futuro nel campo della chemioprevenzione, in particolare come forma di prevenzione primaria.Monoterpenes limonene and its metabolic derivatives, α-terpineol and 1,8-cineol, commonly found as aroma wine components, were studied for their antimutagenicity by the bacterial reverse mutation assay on different strains. Substances were also tested for their antioxidant activity, i.e. radical scavenger, chelation, reduction, and lipid peroxidation inhibition. Limonene and its metabolites, α-terpineol and 1,8-cineol, resulted able to inhibit the chemically-induced mutagenesis, although with a different specificity. The antimutagenicity of limonene has been generally retained by its metabolites and sometimes increased. In particular, α-terpineol exhibited the strongest inhibition, moreover it showed to be a remarkable ferrous ions chelating agent. Limonene and 1,8-cineol were devoid of antioxidant activity. Present results are a starting point in evaluating the potential of α-terpineol as a chemopreventive agent and suggest potential functional dietary benefits of wine
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
The Use of Herbal Products during Breastfeeding: A Study from a Public Italian Hospital.
No full textBackground: The use of herbal products is steadily increasing worldwide, especially by women, also during pregnancy and
breastfeeding, even if safety data are lacking. Aim of this study was to estimate the prevalence of use and the attitude toward
herbal remedies among women during breastfeeding, by an interview-based survey.
Methods: Participants were interviewed after receiving the informed consent, by a structured and validated questionnaire.
Results: Two hundred forty-four breastfeeding women completed the questionnaire. The majority of them were non-smokers
and non-drinkers, whereas they were regular consumers of herbal products during breastfeeding (97%). Medicinal plants most
commonly used were sweet almond oil (68%) and fennel (37%). Herbal products were often associated with other prescription
drugs (89%). Five percent of women have experienced dermatological and gastrointestinal adverse reactions, potentially due to
herbal products.
Conclusions: This study reports that nursing mothers are generally no smokers, avoid alcohol consumption, and they reduce
the use of drugs to those really needed. At the main time, this study highlights that breastfeeding mothers have limited knowledge
on the risk/benefit profile of plant-derived products. As data on the excretion of chemical components of herbal products and their
metabolites in breast milk are lacking, it is generally better to avoid during breastfeeding the use “natural remedies” whose safety
has not been well established
Indagine sull'uso di prodotti naturali e farmaci da parte di donne in gravidanza o allattamento.
No full textScopo dello studio è stato quello di valutare l'uso e la conoscenza di prodotti naturali (cosmetici, omeopatici, prodotti erboristici, ecc.) e farmaci, da parte delle donne in gravidanza (G) e in allattamento (A)
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
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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