1,720,993 research outputs found
What dermoscopy tells us about nevogenesis
No full textThe evolution of nevi is a complex process involving several constitutional and environmental factors. Although histopathology is the gold standard for the diagnosis and classification of melanocytic nevi, the widespread use of in vivo diagnostic technologies such as dermoscopy and more recently of reflectance confocal microscopy, has enriched profoundly our knowledge regarding the morphological variability of nevi in different stages of their evolution. In addition, significant progress has been made in our understanding of genetic alterations and molecular pathways involved in the formation of melanocytic tumors. All this newly acquired knowledge increasingly questions whether morphologically different nevi are also histiogenetically different. In this article, we intend to extract some of the salient points from published clinical and molecular studies on melanocytic tumors and attempt to assimilate them into an integrative concept of nevogenesis
"Dying nevus" or regressing melanoma
No full textEpidemiological studies suggest that the number of acquired melanocytic nevi increases from puberty until midlife and, thereafter, decreases. The latter phenomenon is related to spontaneous involution/apoptosis of nevi. The widespread use of dermoscopy has enriched profoundly our knowledge of the morphological variability of nevi during their evolution. A peripheral symmetric rim of small grown globules represents a clear sign of nevus growth. Instead, nevi in adults often reveal a reticular or reticular-mixed pattern. In patients aged 30 to 40 years clinically vanishing nevi can be noticed, which represent nevi during involution. The important differential diagnoses are melanocytic nevi and melanoma with regression. The life cycle of a nevus is also reflected by the phrase" we are born and we die without nevi"
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Asymptomatic solitary nodule of the forehead
No full textAn asymptomatic 12 mm 3 5 mm pinkish-red solitary nodule on her forehead. Dermoscopically, the lesion showed a background variable from orange to pinkish-red, with telangiectasia with a crown arrangement characterized by in-focus arborizing vessels that did not cross the center of the lesion. The general clinical examination was negative. Excision of the lesion was performed, and the cell population was
S-1001 and CD1a
Variations on the Author
Get PDF“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
Incresed sensitivity to peroxiding agents is correlated with an imbalance of antioxidants in normal melanocytes from melanoma patients.
No full textWe have previously shown an imbalance of the antioxidant system in some cultures of normal melanocytes from patients with melanoma. In order to evaluate if the alteration of the antioxidants could be the basis of an increased sensitivity to exposure to peroxidative agents, in cultured melanocytes from normal individuals (n = 11) and from patients with melanoma (n = 11), superoxide dismutase and catalase activities were evaluated by spectrophotometer, and the levels of vitamin E and of the polyunsaturated fatty acid of cell membranes were determined by gas chromatography mass spectrometry. In 5 out of the 11 cultures of melanocytes from melanoma patients, with respect to those from normal individuals, a significant decrease of catalase activity (Cat) associated with an increase of vitamin E (Vit E) concentration was found, whereas no significant modification of superoxide dismutase activity (SOD) was observed. A wide range of variability was detected in the percentage of the polyunsaturated fatty acids of the cell membranes and a correlation was found between the ratio SOD/Cat and the percentage of linoleic acid, indicating that the imbalance of the enzymatic antioxidants leads to a lipoperoxidative process. The electron microscopic examination of these cultures revealed many microvilli in the plasma membranes and nuclear infoldings and in the cytoplasm light vacuoles. Moreover some cells contained several dense bodies with a round shape and numerous spherical lamellae possibly representing immature melanosomes. Treatment with cumene hydroperoxide between 0.66 and 20 microM did not produce a significant modification of cell viability in melanocytes from normal individuals. On the contrary in melanocytes from melanoma patients correlated with the ratio Vit E/Cat, considered as a parameter of the antioxidant imbalance, a stimulatory effect was observed at 0.66 microM CUH and a cytotoxic effect at 20 microM. In conclusion our results suggest that a constitutional alteration of the scavenger system could be present in normal melanocytes from melanoma patients and that this could be the basis for an increased sensitivity to pro-oxidant agents
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Get PDFWe 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
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