1,721,001 research outputs found
L'ossido nitrico nella terapia anti-protozoaria
No full textL'ossido d'azoto (NO) di orgine endogena ed esogena presenta arttività anti-parassitaria sia sui Protozoi che sui Metazoi. Peraltro, la produzione del NO richiede sofisticati meccanismi di controllo onde evitare danni alle cellule e ai tessuti dell'ospite. I più noti bersagli molecolari per i donatori di NO sono le proteasi a cisteina, che svolgono un ruolo essenziale nel ciclo vitale dei parassiti e nelle interazioni ospite-parassita. Tali enzimi sono pertanto dei potenziali bersagli molecolari per farmaci che basano la propria funzione sul rilascio del NO
Cysteine protease as a target for nitric oxide in parasitic organisms
No full textNitric oxide (NO) is an important cytotoxic and cytostatic mediator for several parasites, including intracellular (e.g. Trypanosoma, Leishmania, Plasmodium, Toxoplasma) and extracellular (e.g. Entamoeba) protozoa and the helminth Schistosoma. Increasing evidence suggests that parasitic cysteine proteases could represent NO targets, providing molecular bases for the parasiticidal effect of NO. NO-donors (e.g. S-nitroso-acetyl-penicillamine, SNAP) inhibitthe catalytic activity of cruzipain, falcipain and Leishmania infantarti cysteine protease in vitro. L. infantum cysteine protease is inhibited following incubation of promastigotes with SNAP, which leads to parasite killing. Although NO-mediated chemical modification(s) of cysteine proteases accounts for the loss of enzyme activity and the parasiticidal effect of NO, the binding of NO to other parasite molecular targets should be taken into account. In particular, ribonucleotide reductase inhibition has been suggested to explain the cytostatic effect of NO on Trypanosoma brucei gambiense and Trypanosoma bruceì brucei. Moreover, the NO-mediated chemical modification(s) of host cysteine-containing proteins could also influence parasite survival.Considering that cysteine proteases appear as promising targets for anti-parasite chemotherapy, NO-releasing drugs could have an enhancing role in thè therapeutic treatment of parasitic diseases
Culling Dogs for Zoonotic Visceral Leishmaniasis Control: The Wind of Change
No full textVisceral leishmaniasis, caused by Leishmania infantum, is a zoonosis, and culling seropositive dogs has been recommended to control the disease in some endemic countries. However, no scientific evidence supports the effectiveness of this strategy to reduce the incidence of visceral leishmaniasis. Economic and ethical issues concerning dog culling are discussed
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
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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