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Confronto tra cultivar di frumento duro in Sardegna nel 1992
No full textRisultati del confronto tra nuove cultivar di frumento duro in diversi campi della Sardegn
Risposta dell'orzo (Hordeum vulgare L.) a differenti livelli di intensificazione colturale
No full text
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
Textural and mineralogical constitution of mineral trioxide aggregate: A comparison among different products
No full textObjectives: To determine the mineralogical, chemical, and microtextural differences between commercially available MTA products, clarifying common differences with Portland and between each other. Materials and methods: The study was done on four commercially available MTA cements, that is Ogna Aureoseal®, Proroot white MTA®, Angelus white and gray MTA® and on a commercial Portland cement. After preliminary X-ray diffraction characterization of the powder, the samples were consolidated following the same procedure used in clinical practice. The consolidated material was embedded in epoxy and polished, and subsequently investigated, by means of SEM-EDS analysis of back-scattered electron images on all samples and of quantitative compositional mapping on MTA. Results: The MTA and Portland cements differ for the grain size, the hydration rate, and homogeneity of the set products, and for lower Fe and S content in MTA. Previously reported presence of opacizing agents (Bi2O3 and CaWO4) was confirmed in all samples, whereas low Al content was not observed in all MTA. Although the MTA products are all mainly composed by di-calcium and tri-calcium silicates, the post-setting texture and the chemical and mineralogical constitution differ. Finer texture was observed in Ogna Aureoseal® and Proroot white MTA®; in Ogna Aureoseal® the presence of apatite and Ca-tungstate was reported; Mg and Al content changed in samples, following the clinker composition. Conclusions: Significant differences exist between Portland cement and MTA, but also among different MTA formulations. MTA products can be classified as a form of Portland cement, specifically modified for dentistry purposes. © 2011 Società Italiana di Endodonzia. Published by Elsevier Srl. All rights reserved
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