1,721,193 research outputs found
Nanotechnological applications in clinical dentistry
Full text linkAl giorno d'oggi, i progressi delle nanotecnologie hanno rivoluzionato drasticamente tutti i campi dell'odontoiatria, dalle malattie orali alla diagnosi, prevenzione e trattamento. Lo scopo di questa tesi di dottorato è stato quello di indagare e valutare l'applicazione delle nanotecnologie nella pratica clinica, con particolare attenzione all'Odontoiatria Preventiva, Estetica e Restaurativa.
La prevenzione della carie e il trattamento precoce delle lesioni sono sfide prioritarie per il clinico. Il design basato su nanomateriali, che include idrossiapatite sintetica o suoi derivati, è in grado di imitare alcune delle proprietà meccaniche e strutturali dei tessuti calcificati nativi e quindi può promuovere la remineralizzazione della struttura dello smalto e prevenire l'ipersensibilità della dentina. Inoltre, l'impiego di nanotecnologie nell'arricchimento di gel sbiancanti mediante nanoforme di idrossiapatite è ampiamente utilizzato per evitare i disagi e i danni associati ai trattamenti sbiancanti.
Uno dei principali usi delle nanoparticelle nell'Odontoiatria Restaurativa è la loro applicazione come riempitivi nei nanocompositi, fornendo elevata duttilità senza perdita di forza e resistenza ai graffi, con proprietà ottiche, meccaniche e termiche migliorate. Inoltre, i nanocompositi mostrano proprietà estetiche migliorate, come un'elevata ritenzione della brillantezza e un'eccellente lucidabilità e adattabilità. Tra queste caratteristiche migliorate, degne di nota sono quelle mostrate dai nuovi compositi bulk-fill. Infatti, grazie al loro nuovo contenuto di monomero e alle migliorate proprietà di polimerizzazione, i compositi bulk-fill consentono di ottenere rapidamente un adattamento soddisfacente del materiale nella cavità, diminuendo il tempo di seduta necessario, garantendo anche adeguate caratteristiche fisiche della superficie.
Pertanto, l'applicazione delle nanotecnologie supporta e facilita le esigenze del clinico, che richiedono protocolli clinici rapidi, sicuri e ripetibili, per ottenere il miglior risultato in un unico appuntamento.Nowadays, developments in the nanotechnology arena have dramatically revolutionized all fields of dentistry from oral diseases to diagnosis, prevention and treatment. The aim of this PhD thesis was to investigate and evaluate the application of nanotechnologies in clinical practice, with particular attention to Preventive, Aesthetic and Restorative dentistry.
Caries prevention and early treatment of lesions are priority challenges for clinicians. Nanomaterial-based design, which includes synthetic hydroxyapatite or its derivatives, is able to mimic some of the mechanical and structural properties of native calcified tissues and can definitely promote the remineralization of the enamel structure and prevent dentin hypersensitivity. Moreover, the employment of nanotechnologies in the enrichment of whitening gels by means of nano-forms of hydroxyapatite are widely used to avoid the discomfort and damages associated with bleaching treatments.
One of the principal uses of nanoparticles in restorative dentistry is their application as fillers in nanocomposites, providing high ductility without strength loss, scratch resistance, enhanced optical, mechanical and thermal properties. In addition, dental nanocomposites exhibit increased aesthetic properties, such as high gloss retention and excellent polishability and adaptability. Among these ameliorated characteristics, noteworthy are those showed by the new bulk-fill composites. Indeed, due to their novel monomer content and enhanced curing properties, bulk-fill composites let to rapidly obtain a satisfactory adaptation of the material into the cavity, decreasing the chair-time needed, while also ensuring adequate physical characteristics of the surface.
Therefore, the application of nanotechnology supports and facilitates the clinician’s needs, which require rapid, safe and repeatable clinical protocols, to obtain the best result in a single appointment
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
The Biology of Intestinal Immunoglobulin A Responses
No full textThe gut mucosa is exposed to a large community of commensal bacteria that are required for the processing of nutrients and the education of the local immune system. Conversely, the gut immune system generates innate and adaptive responses that shape the composition of the local microbiota. One striking feature of intestinal adaptive immunity is its ability to generate massive amounts of noninflammatory immunoglobulin A (IgA) antibodies through multiple follicular and extrafollicular pathways that operate in the presence or absence of cognate T-B cell interactions. Here we discuss the role of intestinal IgA in host-commensal mutualism, immune protection, and tolerance and summarize recent advances on the role of innate immune cells in intestinal IgA production
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