1,720,957 research outputs found
Studio sull'induzione di danno al DNA, micronuclei ed alterazioni del ciclo cellulare da condensato di sigaretta
No full textNumerosi studi confermano l’associazione tra fumo di sigaretta e insorgenza di patologie-polmonari, cardiovascolari e tumori. Il fumo, infatti, contiene diversi composti mutageni c cancerogeni. Premesso che non esiste una sigaretta sicura, è comunque possibile attuare strategie per caratterizzare e ridurre il rischio. In questo studio, abbiamo utilizzato test in vitro per investigare i possibili meccanismi d’azione del condensato di sigaretta (CSC), ovvero la frazione particolata del fumo, assorbita nei polmoni del fumatore e successivamente metabolizzata. Analisi precedenti avevano dimostrato che il CSC, dopo 24h di trattamento induce decremento della vitalità delle cellule Swiss3T3 (IC50 = 130 μg/ml), inibizione dell’efficienza di clonaggio (circa il 60% a`50 μg/ml) e attivazione delle caspasi già a partire dalla prima dose testata (25 μg/ml). La natura degli effetti genotossici del CSC è stata analizzata con il Comet assay che ha evidenziato la capacità del CSC di indurre rotture a singolo e doppio filamento del DNA, dopo trattamenti per 90min e 3 h, a partire dalla dose di 100 μg/ml (p<0.001 Kruskall-Wallis). Il significativo aumento (p<0.001 Mann-Whitney U-test`) delle rotture al DNA è stato osservato dopo 90 min di esposizione a 100 e 150 μg/ml di CSC lascia ipotizzare che la componente ossidativa del danno indotto da CSC venga rapidamente riparata. Il saggio del micronucleo è stato effettuato su cellule trattate con 30 μg/ml di CSC e osservate immediatamente dopo il trattamento e fino a 120h di coltura in terreno completo senza condensato. I risultati ottenuti hanno evidenziato un aumento significativo (p<0.005 t-Student) di cellule micronucleate dopo 72h di recupero. Utilizzando anticorpi anti-nucleari (ANA test) contro il cinetocore è stato possibile mettere in evidenza che il trattamento con CSC esplica prevalentemente un effetto clastogeno. La comparsa dei micnonuclei solo dopo 72h dal trattamento sembra essere correlata al ritardo nella progressione del ciclo cellulare come indicano sia il decremento di cellule in mitosi osservato subito dopo il trattamento, sia l’accumulo dose-dipendente di cellule in G2/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
Compliance to therapy with Dapoxetine in patients affected by Premature Ejaculation
No full textIntroduction: Premature ejaculation (PE) is a sexual dysfunction with high prevalence. According to some reports, it is present in about 20-30% of the male population.
Since 2009 PE has been treated with a novel inhibitor of serotonin re-uptake, Dapoxetine, which has been reported to be specifically active for PE.
Materials and methods: 59 patients have been selected among the patients affected by PE observed at the outpatient department of Urology and Andrology of the "Paolo Giaccone" University Policlinic Hospital of Palermo.
Diagnosis was confirmed unequivocally in all patients, who were suitable for drug treatment and accepted to participate in the study. They were divided in 2 groups: one receiving Dapoxetine (41 patients), another (18 patients) receiving Citalopram. Patients were followed up by telephone at monthly intervals, in order to compare compliance, efficacy and side effects.
Results: Compliance to treatment was obtained in 56% of patients treated with Dapoxetine and in 61% of those treated with Citalopram.
In the Dapoxetine group side effects were reported in 14.6% versus 38.4% in the Citalopram group. Benefit from the treatment was reported in 82% and 69.2%, respectively
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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