1,721,211 research outputs found
Natural rubber biodegradation by Alternaria alternata and Penicillium chrysogenum isolates
No full textIn the present work, the biodegradation of natural rubber by means of three filamentous fungi, two Alternaria alternata strains (ANR and BNR) and Penicillium chrysogenum, is reported. The biodegradation process has been optimized in Erlenmeyer flasks and then scaled-up in Fernbach flasks. The biodegradation was performed in stationary liquid cultures with biomass immobilized on ceramic Berl saddles. In the presence of NR as the only carbon source, the maximum value of enzyme activity (0.242 IU/L) was reached at 41 days of incubation and at the end of incubation time, 65 days, a 2% weight loss of NR was detected. In Fernbach flasks, the maximum peroxidase activity value was doubled (0.500 IU/L) and reached earlier, after 6 days. In the same incubation time, a better biodegradation performance (4.3%) was obtained. Moreover, the application of a double biodegradation step allowed to obtain higher biodegradation percentage, 6.8%. Among the different tested microorganisms, A. alternata BNR showed the best biodegradation potentiality in terms of enzyme production and NR degradation. On the basis of the results obtained in liquid cultures, A. alternata BNR is currently applied in a lab-scale microcosm study which has to be considered the preliminary step of an in-field biodegradation process
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
Agar Plate Methods for Assessing the Antibacterial Activity of Thyme and Oregano Essential Oils against S. epidermidis and E. coli
Full text linkThe resistance to antimicrobials (AMR), especially antibiotics, represents a serious problem and, at the same time, a challenge. In the last decade, a growing interest in the use of essential oils (EOs) as antimicrobial substances was observed. Commercial thyme and oregano EOs are reported to be the main responsible of the oil antimicrobial efficacy against both Gram-positive and Gramnegative pathogenic bacteria. The aim of the present work was to study the efficacy of EOs against Staphylococcus epidermidis and Escherichia coli in long-time treatments. In a preliminary microdilution test, a MIC value was obtained for thyme EO against S. epidermidis and E. coli. After that, disk diffusion and disk volatilization tests were set up to study the influence of main cultural parameters on EO activity in liquid or vapor phase. Both bacteria were inhibited by thyme and oregano EOs when applied pure (100% v/v) or diluted (75% and 50% v/v): a higher inhibition was observed in a disk diffusion test in which the antimicrobial effect was due to both liquid and vapor phase components. Finally, a comparison with literature data was carried out even if it was not so easy because standard methods are usually modified and adapted to specific case study. For this reason, the results have to be interpreted in relation to the analytical method applied
Confronto al SEM di sei superfici implantari SLA.
No full textL'obiettivo della ricerca da parte degli autori è quello di analizzare e confrontare la microstruttura della superficie SLA di sei impianti di altrettante case produttrici diverse, dopo l'applicazione e successiva rimozione degli stessi dal sito operatorio.
Gli impianti immediatamente dopo la rimozione, previo l'immersione preparatoria in bagno ultrasonico, sono stati osservati al SEM a ingrandimenti crescenti 100X, 1000X,2000x e 4000X evidenziando una serie di modificazioni della superficie atte a determinare una variabilità del successo clinico
Superfici implantari. Valutazione critica delle otto più trattate in letteratura
No full textLo scopo del presente lavoro è di esaminare la microstruttura delle superfici implatari dei più diffusi impianti in commercio, sono stati pertanto valutati gli impianti in titanio tipo 4 con superficie sabbiata, mordenzata, sabbiata e mordenzata (SLA), rivestite in titanio plasma sprayed (TPS), rivestite in idrossiapatite, mordenzate e rivestite in fosfato tricalcico (brushite). Tutto ciò ha consentito di dimostrare che note le caratteristiche della superficie implantare è possibile ottimizzare la scelta del tipo d'impianto in rapporto al caso clinic
La stomatite aftosa ricorrente: clinica e terapia.
No full textNel presente lavoro gli autori descrivono dettagliatamente caratteristiche etiopatogenetiche e cliniche delle principali forme di patologia aftosa indicando i possibili legami tra le lesioni aftose e alcune patologie di carattere sistemicoe quindi correlando ai vari quadri clinici i possibili presidi terapeutici disponibili
Lo sviluppo del burnout: uno studio longitudinale su un campione di infermieri
No full textScopo di questo lavoro è di valutare l’evoluzione del burnout nel corso della carriera lavorativa su
un campione di infermieri professionali. L’ipotesi, in linea con i contributi presenti in letteratura
secondo cui sono i neo-assunti i soggetti a maggior rischio di burnout, prevede di rilevare una
diminuzione dei livelli di burnout nel tempo.
L’indagine longitudinale è stata condotta in 4 diversi momenti della carriera lavorativa: l’ultimo
anno di scuola, dopo 6 mesi dall’entrata nel mondo lavorativo, dopo 1 anno e dopo 13 anni.
I risultati ottenuti sembrano smentire la nostra ipotesi. I dati evidenziano due momenti critici: la
fase di “iniziazione” al lavoro e, soprattutto, l’ultima rilevazione, che si caratterizza come quella
con i maggiori livelli di burnout
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