1,721,001 research outputs found
Cone Beam CT use in the pre-prosthetic evaluation of endodontically treated of the rear maxilla
Full text linkWith our study we wanted to compare the diagnostic accuracy of conventional radiography (orthopanoramic and intraoral radiography) and Cone Beam CT (CBCT) for the diagnosis of periapical lesions on the posterior elements of the upper maxilla endodontically treated.
The images were analyzed by a radiologist and an endodontist whose interpretation of radiological examinations is unique. Were examined 34 molars (23 first molars and 13 second molars) with a total of 102 roots. The CBCT detected a significantly higher number of lesions (43%, p <0.001) compared to conventional radiography. Our results demonstrate that the CBCT can be inserted into the diagnostic routine for the evaluation of all pre-prosthetic posterior elements of the upper jaw endodontically treated in addition to the diagnostic techniques 2D, especially when in the treatment plan is provided the realization of an abutment. The CBCT, which has reduction of cost and absorption of radiation with respect to the conventional CT, is also very useful even when there is a need to perform a surgical treatment-endodontic (apicectomy) of a lesion diagnosed with 2D techniques
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
Non-Gaussian diffusion NMR discriminates between low- and high-risk prostate cancer.
No full textProstate cancer (Pca) is the second most common malignancy and the fifth leading cause of death in men
worldwide. Current diagnostic methods, based on PSA measurement and biopsy, are limited by low
specificity (36%) and invasive procedures; moreover, 30% of tumor-grade were under-estimated[1]. High-
grade PCa is treated with more aggressive therapy, including surgery or radiations, than low-grade PCa;
discriminating correctly different tumor grade is mandatory to plan patient treatment. Prostate tissue has a
glandular structure, composed by several compartments: acini, formed by secretory cells and connected to
ducts; the glandular structure is supported by the connective tissue of stroma.
PCa development is characterized by microstructural modifications, due to the growth of undifferentiated
cells and alteration of cell membranes, that change each compartment volume fraction[2].
The Diffusion-weighted NMR (DW-NMR) imaging is sensible to the tumor modifications, since this
technique exploits the diffusion of biological water molecules as an endogenous contrast agent.
Diffusion is the stochastic thermally-induced displacement of molecules, that colliding with the structures
and barriers they encounter during motion, probe the tissue and reveal its histoarchitecture at microscopic
scale, non-invasively. By using a couple of pulsed magnetic-field gradients, the NMR acquired signal,
named DW signal, is proportional to the Fourier Transform of molecules motion propagator; if the
displacements probability distribution (dpd) is Gaussian-shaped, as it happens in homogeneous media, the
signal mono-exponentially decays. Nevertheless, prostate, as any biological systems, is a complex and
inhomogeneous media, which exhibits a non-Gaussian diffusion. In order to obtain additional information
on tissue microstructures, inaccessible to Gaussian-diffusion NMR technique, we estimate the Kurtosis, i.e.
the fourth-order term of the cumulant expansion, that quantifies the deviation of dpd from a Gaussian
distribution, providing a measure of tissue heterogeneity[3].
In this work, we compare two NMR technique, Diffusion Tensor Imaging (DTI) and Kurtosis Imaging
(DKI), based respectively on Gaussian and non-Gaussian diffusion, to test their diagnostic potential in PCa
identification and stadiation.
31 patients with different tumor grades (TG) PCa were enrolled to be examined by a 3T scanner, after two
months from the first biopsy. Diffusion-weighted images were acquired with 5 different diffusion weights,
i.e. b-values up to 2500s/mm^2. Parametric maps of Mean Diffusivity (MD) and apparent Kurtosis (K)
were obtained by using an in-house algorithm developed in Matlab.
One-way ANOVA was performed to test statistical significance of differences in MD and K values
calculated in benign prostate and in PCa among different TG. The linear correlation between diffusion
parameters and the tumor grade was estimated by the Pearson's test.Malignant tissue shows a significantly higher K and lower MD values compared to the healthy tissue
(p<10 -4 ).
K-values of PCa were positively correlated with TG (r=0.37;p<0.004), while MD-values were negatively
correlated with TG (r=-0.31;p=0.02). Both K and MD can significantly discriminate between low- and
high-grade PCa; however K showed the highest significance (p K =0.005;p MD =0.015).
These results may be explained considering that, in healthy prostate, water diffusion is almost free in acini
and ducts, restricted in stroma and highly restricted in secretory cell layer. The histopathological evidences
show that tumor progression causes prostate glands to change in size and shape and malignant cells to
infiltrate compartments. The overall effect of these modification lead to a decrease of diffusivity and an
increase of heterogeneity.
Our results demonstrate that non-Gaussian diffusion parameter K is more sensitive to tumor-induced
microstructural changes, suggesting that DKI could provide a reliable, non-damaging and less expensive
diagnostic exam. Since DKI is a non-invasive technique, it also could be employed to follow-up patients,
evaluating therapy response.
[1] Ferlay, J. et al., Int. J. Cancer, (2015): E359–E386.
[2] Nezzo, M. et al., European Journal of Radiology, (2016); 85:1794-1801.
[3] Jensen JH, Helpern JA. NMR Biomed, (2010);23:698-710
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
Identità comunitaria tra museo grandi cicli di decorazione pubblica e città. Peculiarità, potenzialità e criticità di un progetto di ricerca condiviso.
No full textIl saggio ripercorre gli obiettivi e i risultati della ricerca focalizzata sullo studio comparativo dei fenomeni artistici e architettonici che hanno cercato di definire l'identità comunitaria di alcune città Italiane tra l'Unità d'Italia e il secondo conflitto mondiale, ovvero Milano, Brescia, Verona, Padova e Napoli. Il saggio descrive anche il repository e il sito web dove sono stati riversati e ragionati materiali e risultati della ricerca.The essay traces the objectives and results of the research focused on the comparative study of artistic and architectural phenomena that have tried to define the community identity of some Italian cities between the Unification of Italy and the Second World War, namely Milan, Brescia, Verona, Padua and Naples. The essay also describes the repository and the website where the materials and results of the research have been poured and reasoned
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
L'Università nella città
No full textIl saggio introduttivo di un volume dedicato al patrimonio artistico dell'università di Padova analizza lo stretto rapporto tra l'università, attestata per la prima volta nel 1222 e la città, dalla fase medievale, in cui non esistevano spazi specifici deputati all'insegnamento, alla costruzione dell'edificio rinascimentale, ancora oggi sede del rettorato, fino agli ampliamenti novecenteschi e all'attuale politica di espansione con la realizzazione di nuovi edifici e la rigenerazione urbana di intere aree all'interno perimetro urbano. Il volume, destinato ad un più largo pubblico, è suddiviso in due parti. 4 saggi analizzano le tematiche principali nella prima parte, nella seconda sono analizzate le opere in contributi specifici dedicati a ciascun edificio, affidati a specialisti della materia. Il volume presenta un ricco apparato illustrativo, concepito come un'asse portante dell'intero volume, in gran parte realizzato appositamente. Ogni saggio è corredato da una bibliografia ragionata, posta alla fine del volume insieme all'indice dei nomi
Diagnosis and treatment of paranasal sinus fungus ball of odontogenic origin: case report
Full text linkIn recent years the incidence of fungal sinusitis has increased considerably, due both to increased survival of patients at risk and to improved diagnostic equipment. The pathogen responsible in most cases is the Aspergillus in its forms Fumigatus, Flavus and Niger. The diagnosis is often delayed because the symptoms, characterized by headache, cough, and facial algia, are generally similar to that of chronic bacterial rhinosinusitis. It can be divided into invasive and non-invasive forms based on the clinical evolution and extent of the lesion. We report a case of
non-invasive fungal rhinosinusitis in a patient with recurrent sinusitis and pain in the left maxillary region, resistant to antibiotic therapy
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