1,721,096 research outputs found
Gastric cancer carcinogenesis and tumor progression
No full textBACKGROUND:
Gastric cancer (GC) remains one of the leading causes of cancer-related deaths worldwide, even though a decline has been observed in its incidence and the mortality rate in recent decades. Gastric carcinogenesis is a complex phenomena involving multiple epigenetic and genetic factors; several genetic, environmental and infectious agents interact causing a cumulative effect in the early steps of gastric carcinogenesis.
MATERIALS AND METHODS:
The most commonly used classifications of GC are the World Health Organization (WHO) and the Laurén classifications which describes two main histological types, diffuse and intestinal, which have different clinicopathological characteristics. Diffuse cancer occurs more commonly in young patients, can be multifocal, is not often accompanied by intestinal metaplasia and can be hereditary, in which E-cadherin alteration plays a pivotal role. Intestinal type is more frequently observed in older patients and follows multifocal atrophic gastritis. This is usually accompanied by intestinal metaplasia and leads to cancer via dysplasia, and thus intestinal metaplasia is considered a dependable morphological marker for GC risk. Intestinal adenocarcinoma predominates in the high-risk areas whereas the diffuse adenocarcinoma is more common in low-risk areas.
DISCUSSION:
Classically, genetic instability and Helicobater pylori (H. Pylori) infection are often identified in intestinal GC. The great majority of GCs are sporadic and result from the cumulative effects of different environmental risk factors; smoking, alcohol consumption and dietary habits have been addressed as significant. H. Pylori infection and proinflammatory cytokine gene polymorphisms represent other features of this compound process that leads to the development of GC. Other molecular pathway well described in GC is microsatellite instability (MSI) that related with specific clinic-pathological features.
CONCLUSION:
In this review we focused on the role of H. Pylori infection, MSI and alterations of CDH1 (E-Cadherin) gene
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
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
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
Target gene mutation profile differs between gastrointestinal and endometrial tumors with mismatch repair deficiency
No full textMutation frequencies at 25 genes containing coding repeats were comparedin colorectal, gastric, and endometrial mismatch repair-deficient (MSI-H) tumors. The overall number of mutations was significantly lower in endometrial than in gastrointestinal MSI-H cancers. Using a likelihood statistical method, target genes were divided in each tumor location into two groups likely to represent gene mutations that do or do not provide selective pressures during tumoral progression. Mutation profiles were quite similar in gastric and colorectal MSI-H cancers but were different in endometrial MSI-H tumors. Deletions in Bat-25 and Bat-26 noncoding repeats were also significantly less important in endometrial as compared with gastrointestinal MSI-H tumors. Our results show that the profile of target gene mutations in MSI-H tumors is tissue specific, with both qualitative and quantitative differences between gastrointestinal and endometrial MSI-H cancers
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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