1,720,969 research outputs found
Computed Tomography of dental arches with dedicated software: current state of applications.
No full textSince the introduction of the "Dentascan" reconstruction program, the use of CT in the field of odontostomatology has attracted growing interest from both radiologists and dentists. Over the years, the potential applications of Dentascan have extended from the management of implantology-related issues to the study of all jaw bone diseases relevant to dentists. This paper describes the technical aspects and current diagnostic capabilities of computed tomography of the dental arches with dedicated software, by presenting a wide selection of case studies
Modified translabyrinthine approach and hearing preservation: imaging evaluation.
No full textTo establish if the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of the vestibule, after the removal of vestibular schwannoma by a modified translabyrinthine approach, correlate with a successful outcome, defined as hearing preservation. Our study group consisted of 16 patients with vestibular schwannoma. All patients' pre-operative hearing was graded as class one or two according to the Gardner-Robertson scale. On MRI scans, the schwannoma, including the intracanalicular segment, were less than 2 cm in size in all the patients. The intracanalicular portion involved the fundus of the internal auditory canal in seven patients. In the remaining nine patients, the schwannoma had spread to involve two-thirds of the meatus, sparing its lateral third. The state of the labyrinth, in particular the integrity of the vestibule, was evaluated by CT scans and MRI prior to and following surgery. The schwannoma was completely removed in all patients. None showed any signs of persistence or tumoral relapse on the post-operative MRI. The final follow up showed that seven patients had maintained their hearing function (i.e. four patients with class one hearing and three with class two). The MRI vestibular signal on the T2-weighted images was well depicted only in patients with hearing preservation. Bony vestibular integrity was observed in the CT scans of all cases with hearing preservation, and also in three cases with failure of hearing preservation. Our results confirm that total isolation and maintenance of an anatomically intact vestibule, as depicted by MRI examination, is one of the fundamental factors for successful preservation of hearing function following modified translabyrinthine approach schwannoma removal
[MRI evaluation of morpho-structural alterations of the retrodiscal tissue in condylo-meniscal incoordination of the TMJ: usefulness of individualised T2-weighted TSE sequences].
No full textPURPOSE: To assess and evaluate morpho-structural alterations of the retrodiscal tissue of the temporomandibular joint (TMJ) that may be seen in chronic trauma of the condylo-meniscal incoordination through magnetic resonance (MR), using T2-weighted TSE sequences. MATERIALS AND METHODS: The study included 40 patients, 6 male and 34 female, age range 12-66 years, mean age 28.5 years. According to the Wilkes classification, TMJs of patients were graded as follows: 10 grade 1 TMJs; 28 grade 2, 16 grade 3, and 26 grade 4. Scans were obtained with a 1.5 T MRI unit, and a dedicated surface coil, using T2-weighted TSE sequences (TR 3000-3500, TE 90-100), 2 acquisitions, 256x256 matrix, 3-mm section thickness, with a 0-mm interval, and 2'30" duration for a single acquisition. Scans were obtained both during opening and during closure of the mouth, on 3 planes: sagittal oblique, perpendicular to the condylar long axis; coronal oblique, perpendicular to the anteroposterior axis of the discs; and axial, perpendicular to coronal scans. Parameters used were the following: presence or absence of retrodiscal fibrosis; morphology of the retrodiscal fibrosis in scans taken during mouth opening in the four grades of the Wilkes classification; dimensions of the retrodiscal fibrosis in scans taken during mouth opening, in the four grades of the Wilkes classification, in an anteroposterior direction, measuring the longest distance on parasagittal planes on a horizontal line touching the outer edge of the disc and the most-distal point of fibrosis, and in a vertical direction, measuring the distance between the highest and lowest points of fibrosis; signal intensity features within the fibrotic area. RESULTS: In all TMJs analysed, it was possible to confirm the presence of retrodiscal tissue fibrosis, which was more or less evident according to the grading of the dysfunction/disease, to the extent of mouth opening, and to displacement with or without reduction of the articular disc. In grade 1 TMJs, fibrosis looked like a truncated cone; in grade 2, fibrosis looked like a cone; in grade 3, it was either shaped like a mushroom placed horizontally, with the stalk towards the disc, or else ribbon-shaped; in grade 4, it had an inhomogeneous, irregular ribbon shape. CONCLUSIONS: MR studies of TMJ dysfunction through T2-weighted TSE sequences allowed us to evidence in all cases the sclerotic alterations of the retrodiscal tissue, and to assess their form and dimensions. Furthermore, it was possible to evidence both the pathognomonic features of retrodiscal tissue fibrosis resembling a mushroom, and the characteristic brace-shape the upper and lower layers take on during mouth opening in TMJs with a disc displacement with reduction
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
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