1,721,021 research outputs found
INFLUENCE OF THE VALVE METAL-OXIDE ON THE PROPERTIES OF RUTHENIUM BASED MIXED-OXIDE ELECTRODES .1. TITANIUM SUPPORTED RUO2/TA2O5 LAYERS
No full textRuO2/Ta2O5 mixed oxide electrodes have been investigated by XPS-AES techniques and X-ray diffractometry and their electrochemical behaviour for the oxygen evolution reaction has been studied. The surface analysis indicated a relative insensitivity of the surface composition to the changes of the Ru/Ta ratio in the bulk of the coatings. The diffractometric study showed the existence of a RuO2 rutile phase and a Ta2O5 amorphous phase in the electrode materials. no evidence for solid solutions was found. The influence of the noble metal concentration in the coatings on their catalytic activity has been studied for different oxide loadings. Maxima of Activity for a Ru/Ta atom ratio close to 1 have been found for coating thicknesses of 1 μm. Thicker layers exhibit an activity increasing with the noble metal content. The correlation between anodic charge density, q*, and current density, i, for the oxygen evolution reaction has been tested and definite trends related to the morphology of the electrode material have been assessed. © 1986
Raccomandazioni sull’uso dei mezzi di contrasto organo-iodati e per Risonanza Magnetica per via iniettiva. Considerazioni radiologiche e medico-legali
No full textEntropy and uniformity as CT perfusion measures may predict survival in lung cancer
No full textComputed Tomography perfusion (CTp) is a functional imaging technique, which allows detecting the presence of tumour abnormal vascular patterns, through the temporal analysis of the tissue density variations. The aim of this study is to extract meaningful statistical features from CTp colorimetric maps of lung cancers that could act as a surrogate prognostic image-based biomarker
Effects of Guided Random Sampling of TCCs on Blood Flow Values in CT Perfusion Studies of Lung Tumors
No full textRationale and Objectives: Tissue perfusion is commonly used to evaluate lung tumor lesions through dynamic contrast-enhanced computed tomography (DCE-CT). The aim of this study was to improve the reliability of the blood flow (BF) maps by means of a guided sampling of the tissue time-concentration curves (TCCs). Materials and Methods: Fourteen selected CT perfusion (CTp) examinations from different patients with lung lesions were considered, according to different degrees of motion compensation. For each examination, two regions of interest (ROIs) referring to the target lesion and the arterial input were manually segmented. To obtain the perfusion parameters, we computed the maximum slope of the Hill equation, describing the pharmacokinetics of the contrast agent, and the TCC was fitted for each voxel. A guided iterative approach based on the Random Sample Consensus method was used to detect and exclude samples arising from motion artifacts through the assessment of the confidence level of each single temporal sample of the TCC compared to the model. Removing these samples permits to refine the model fitting, thus exploiting more reliable data. Goodness-of-fit measures of the fitted TCCs to the original data (eg, root mean square error and correlation distance) were used to assess the reliability of the BF values, so as to preserve the functional structure of the resulting perfusion map. We devised a quantitative index, the local coefficient of variation (lCV), to measure the spatial coherence of perfusion maps, from local to regional and global resolution. The effectiveness of the algorithm was tested under three different degrees of motion yielded by as many alignment procedures. Results: At pixel level, the proposed approach improved the reliability of BF values, quantitatively assessed through the correlation index. At ROI level, a comparative analysis emphasized how our approach "replaced" the noisy pixels, providing smoother parametric maps while preserving the main functional structure. Moreover, the implemented algorithm provides a more meaningful effect in correspondence of a higher motion degree. This was confirmed both quantitatively, using the lCV, and qualitatively, through visual inspection by expert radiologists. Conclusions: Perfusion maps achieved with the proposed approach can now be used as a valid tool supporting radiologists in DCE-CTp studies. This represents a step forward to clinical utilization of these studies for staging, prognosis, and monitoring values of therapeutic regimens
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
Short-term onset of fatal pulmonary toxicity in a patient treated with intravenous amiodarone for post-operative atrial fibrillation.
No full textNo abstract availabl
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
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