1,720,957 research outputs found
Contributo al safety assessment dei semi di finocchio dolce e dell’estragolo: citotossicità, apoptosi e genotossicità in cellule umane HepG2
No full textTisane e infusi di semi di finocchio (Foeniculum vulgare Mill.) nella var. dulce (finocchio dolce) sono utilizzate nella medicina tradizionale di popoli Europei ed Asiatici per la prevenzione della flautolenza e delle coliche del lattante. Gli effetti farmacologici dei semi di finocchio sono stati attribuiti ai numerosi componenti dell’olio essenziale tra i quali l’estragolo, un alchenilbenzene che ha recentemente richiamato l’attenzione della comunità scientifica in quanto è risultato essere cancerogeno a livello epatico in roditori trattati con elevate concentrazioni. A nostra conoscenza, però,
non esistono dati in letteratura condotti su cellule di derivazione umana o studi epidemiologici che possano confermare la cancerogenicità osservata nell’animale da esperimento. Lo scopo del presente lavoro è quello di contribuire alle conoscenze circa la capacità di indurre citotossicità, apoptosi e genotossicità della polvere impalpabile (PI) di semi di finocchio dolce e del composto puro estragolo nei confronti di una linea cellulare umana stabilizzata di derivazione epatica HepG2. A tale scopo sono state analizzate tre concentrazione scalari dei composti allo studio (rispettivamente 40.00, 20.00 e 10.00 μg/ml per la PI dei semi di finocchio e 84.55, 42.28 e 21.14 μg/ml per estragolo) scelte sulla base della massima solubilità dei campioni. Cellule HepG2 in fase esponenziale di crescita sono state trattate per 4 ore con i composti allo studio, le prove sono state ripetute in triplicato ed in ogni set sperimentale sono stati inclusi idonei controlli negativi e positivi. La citotossicità è stata valutata con il test MTT, lo studio dell’apoptosi (nelle sue fasi precoci) è stato effettuato valutando la depolarizzazione della membrana mitocondriale attraverso la marcatura con la sonda cationica lipofilica JC-1, mentre la genotossicità è stata valutata con il test della cometa in condizioni alcaline che evidenzia la capacità di uno xenobiotico di indurre danno primario al DNA inteso come rotture del singolo o del doppio filamento della catena fosfodiesterica.
I risultati ottenuti hanno mostrato che la PI di semi di finocchio ed estragolo non esercitano, nelle condizioni sperimentali applicate, né azione citotossica né azione genotossica nei confronti di cellule HepG2. Lo studio delle capacità apoptotiche ha dato, invece, risultati diversi: la PI dei semi di finocchio non ha indotto la depolarizzazione mitocondriale legata alle fasi iniziali della apoptosi a nessuna delle concentrazioni testate, mentre circa il 15% di cellule trattate con la concentrazione più elevata di
estragolo sono risultate in apoptosi precoce
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
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
Valutazione dell’attività antigenotossica di un prodotto lassativo a base vegetale (Sollievo, Aboca SpA)
No full textkoamabayili/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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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