1,720,961 research outputs found
Biofilms: stato dell'arte
No full textIn questo editoriale gli Autori descrivono la morfologia e la biologia dei biofilms formati da microrganismi, la loro importanza in differenti infezioni croniche e la possibilità di nuove strategie terapeutiche per il trattamento di queste infezioni. I biofilms sono una struttura complessa e organizzata, consistente in microcolonie circondate da una matrice esopolisaccaridica (slime) nella quale sono scavati minuscoli canali d’acqua che si anastomizzano fra loro, formando una sorta di sistema circolatorio primitivo. I biofilms possono organizzarsi sulla superficie di
differenti mucose o sulla superficie di dispositivi medici impiantati o inseriti nel corpo. Molecole-segnale prodotte dai microrganismi stessi, condizionano la formazione, lo sviluppo dei biofilms e l’interazione tra i microrganismi. A causa della presenza dell’involucro polisaccaridico, che agisce come un sistema di protezione che si oppone alla penetrazione dei farmaci, i microrganismi presenti nel biofilm, mostrano un’aumentata resistenza alle difese immunitarie dell’ospite e alla terapia antibiotica rispetto alle forme planctoniche. Conseguentemente, i biofilms rivestono un’importanza rilevante per la salute, dato il loro ruolo in molte infezioni croniche e la loro importanza in un numero elevato di infezioni da impianti biomedici; queste infezioni, a carattere recidivante, sembrano intrattabili con antibiotico-terapia. Una sostanza mucolitica, N-acetilcisteina (NAC) ha dimostrato una buona attività nell’inibire l’adesione batterica e nel dissolvere la matrice del biofilm. Recenti risultati sperimentali hanno confermato l’efficacia di NAC nella disgregazione e nella riduzione del numero di forme vitali di batteri presenti nei biofilms, rispettivamente di Staphilococcus aureus ed Escherichia coli. In questi studi è stata anche messa in evidenza l’efficacia di due noti antibiotici, tiamfenicolo e fosfomicina trometamolo, utilizzati rispettivamente nelle infezioni respiratorie e nelle infezioni urinarie non complicate. Particolarmente interessante la nuova osservazione circa l’attività in associazione di NAC ed i singoli antibiotici che è risultata sinergica aprendo nuove importanti prospettive terapeutiche in patologie infettive croniche delle vie respiratorie e delle vie urinarie determinate da microrganismi formanti biofilms che, come è noto, è quasi impossibile eradicare con le comuni terapie antibiotich
Amino acid and codon use: in two influenza viruses and three hosts [Utilisation de codons et d'acides aminés : chez deux virus de la grippe et chez trois hotes]
No full textOBJECTIVE: The aim of this study was to compare the use of amino acids and codons in influenza viruses A and B and in their common hosts, to highlight any relevant difference. METHODS: The frequency of the 20 amino acids and of the 61 codons was studied in influenza viruses A, B, and in man, pig, and chicken. The correlation in amino acid and codon use among these hosts was calculated. RESULTS: The correlation between the frequency of the 20 amino acids and the molecular weight was also calculated and it was very similar in all studied hosts, ranging from 0.506 to 0.595. The correlation of codon frequency among these organisms was highest between man and chicken (r=0.974), and lowest between pig and virus B (r=0.147). CONCLUSIONS: The important correlation in codon use among the three hosts and the two viruses suggests there was a remote lateral gene transfer among the three hosts and the two viruses. The higher use of alanine, leucine, and proline in man versus virus A is significan
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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