1,720,999 research outputs found
Design of a Library of Potential Inhibitors to Farnesyltransferase
No full textInsight
Pancreatic cancer is the fourth most common cause of cancerrelated deaths. Patients have a survival rate of less than 5% within a five-year span. On average, patients die about two and a half years post-diagnosis after the cancer spreads.
Why?
Pancreatic cancer is difficult to detect during its early stages because its symptoms are not obvious. As a result, pancreatic cancer is typically in its advanced form once diagnosed. At this point, the cancer is difficult to eliminate because the tumors may have spread to other tissues, or metastasized.
What is the pancreas?
The pancreas is a vital digestive gland that aids in digestion of food by secreting digestive enzymes that combine with pancreatic juice to break down protein, fats, and sugars. Aside from secreting enzymes, the pancreas also secretes hormones such as insulin and glucagon to regulate glucose levels.
Target
Generally, healthy cells grow and divide with the help of a signal transmitted by the Ras protein. Ras is a “G-protein” because guanine nucleotides (GTP and GDP) are bound to them. Ras is turned on by replacing GDP with GTP. When Ras protein is activated, it signals the cells to grow by MAP Kinase cascade. When the gamma phosphate is hydrolyzed off the GTP and converted back to GDP, Ras is turned off and cell growth is signaled to stop. Mutations in Ras cause its signal to be constitutively, or continuously, expressed and lead to uncontrolled signaling for cell growth. Ras depends on post-translational modification by the zincmetalloenzyme farnesyltransferase (FTase). After translation, Ras goes through four modification steps; the first step includes FTase. The farnesyl group is necessary for Ras to attach to the cell membrane. If Ras does not attach to the cell membrane, then Ras cannot transfer signals from receptors and signal the cell to grow. If the post translational modification of farnesyltransferase is inhibited by small molecule inhibitors, mutant Ras is mislocalized. When the constitutively active Ras is mislocalized the MAP Kinase cascade is disrupted and the uncontrolled cell growth is halted
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
- …
