1,721,010 research outputs found
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
Absence of BRAF mutations in endocrine tumors
No full textBackground: Chromogranin A (CgA) is considered the most accurate marker in the diagnosis of gastro-entero-pancreatic (GEP) endocrine tumors. Pancreatic polypeptide (PP) has also been proposed to play this role, but then not used due to its low sensitivity. The aim of the present study was to determine whether the assessment of PP would improve the diagnostic reliability of CgA in patients with GEP tumors. Patients and methods: Both markers were assessed in 68 patients [28 functioning (F), 40 non functioning (NF)]. Twenty-seven patients disease-free (DF) after surgery, and 24 with non-endocrine tumors (non-ETs) were used as control groups. Results: CgA sensitivity was: 96% in F, 75% in NF, 74% in pancreatic, and 91% in gastrointestinal (GI) tumors. Specificity was 89% vs DF, and 63% vs non-ETs. PP sensitivity was: 54% in F, 57% in NF, 63% in pancreatic, and 53% in GI tumors. Specificity was 81% vs DF, and 67% vs non-ETs. By combining the two markers a significant gain in sensitivity vs CgA alone was obtained: overall in GEP tumors (96% vs 84%, p=0.04), in NF (95% vs 75%, p=0.02), and in pancreatic (94% vs 74%, p=0.04). More specifically, a 25% gain of sensitivity was obtained in the subgroup of NF pancreatic tumors (93% vs 68%, p=0.04). Conclusion: The combined assessment of PP and CgA leads to a significant increase in sensitivity in the diagnosis of GEP tumors, particularly in pancreatic NF
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
BRAF mutations in an Italian cohort of thyroid cancers
No full textOBJECTIVE: Recently, a somatic point mutation of the BRAF gene (V599E) has been identified as the most common genetic event in papillary thyroid carcinoma (PTC) with a variable frequency (about 25-70%) in different series from USA, Japan, Portugal and Ukraine. DESIGN: In the present study, the genetic analysis of BRAF in an Italian cohort of 65 thyroid tumours with corresponding normal tissues and 21 thyroid benign disorders is reported. METHODS: For BRAF analysis, the somatic DNA was PCR amplified by means of specific intronic primers and PCR products were directly sequenced. Statistical analyses were obtained by means of Fisher's exact test. RESULTS: All mutations detected involved a T > A transversion at 1796 (V599E) and were heterozygous. Overall, BRAF V599E mutation was found in 18/58 (32.1%) PTCs. According to the histological type of the tumour, the mutation was present in 38.3% of cases of conventional PTC (18/47), in 0/6 follicular variant of PTC, in 0/ 3 oncocytic variant of PTC. No BRAF mutations were detected either in five follicular carcinomas, or in four poorly differentiated or undifferentiated cancers or in benign thyroid disorders. No statistically significant correlation of BRAF mutation with patient age and gender, with multicentricity of the tumour, with the lymphocytic infiltration of the tissue, with the stage and with the recurrence rate, was found. BRAFV599E tended to be associated, although not significantly, with a greater volume and extension of the tumour and with lymph-nodal metastases at surgery. CONCLUSIONS: In conclusion, the present study on the first Italian series of thyroid cancers shows a frequency of 38.3% of BRAFV599E in the classical variant of PTC, confirming the key role of this mutation in promoting tumourigenesis
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
Analysis of a deiodinase 2 polymorphism (oRFa-Asp) in patients with Graves’ disease and controls : preliminary results
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Fetal cell microchimerism in papillary thyroid cancer : a role in the outcome of the disease
No full textFetal cell microchimerism (FCM) is defined as the persistence of fetal cells in maternal organs and circulation without any apparent rejection and it was hypothesized to protect toward the onset of some neoplastic diseases. To verify the role of FCM in papillary thyroid cancer (PTC), we enrolled 87 parous women with PTC and at least one male pregnancy preceding the diagnosis (PTC-P), 66 healthy women with 1 or more male children (HC-P) and 57 nonparous women with PTC (PTC-NP). The presence of circulating male DNA was assessed by the amplification of the Y chromosome-specific gene SRY, with a sensitivity of 1 male cell/1 million female cells. A significantly higher frequency of FCM was found in HC-P than PTC-P women (63.6% vs. 39.1%, p = 0.004). Among PTC-P patients, those positive for the presence of FCM (FMC+ve) had a lower prevalence of extrathyroidal extension (p = 0.027) and lymph node metastases (p = 0.044) than those without FCM (FMC-ve). Moreover, FMC+ve patients were more frequently in remission than FMC-ve cases (94.1 vs. 67.9%, p = 0.009). Interestingly, we showed for the first time that the positive effect on tumor presentation and outcome is specifically related to FCM and it is not an effect of pregnancy. In conclusion, circulating FCM is significantly more frequent in healthy parous women than in women with PTC. Moreover, the presence of circulating fetal male cells is associated with a significantly lower extrathyroidal extension and a good prognosis, suggesting a protective role of this phenomenon toward both the onset and the progression of thyroid cancer
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