1,720,960 research outputs found
Sintesi di nuovi inibitori della Topoisomerasi II e della Protocheinchinasi CK2 con potenziale attività antitumorale
Full text linkThe Topoisomerase inhibitors play an essential role in the research of new molecules useful in the antitumor therapy. Topoisomerases are enzymes that regulate the topology of the DNA macromolecule. There are two type of Topoisomeases: Type I are enzymes that cleave single strand of DNA, type II cleaves both strands of DNA and they play an essential role on the cell life. The Topoisomerases are the targets of many antitumor agents currently used in the clinical practice.
Proteinkinase CK2 is another interesting target for the potential anti-neoplastic drugs. CK2 is a messenger-indipendent kinase that plays an essential role in cell growth and proliferation.
Some studies underline the interaction between Topoisomerase II and proteinkinase CK2 as CK2 is involved in the control of Topo II activity and programmed cell death (apoptosis). The synergism between Topoisomerase II inhibitors and CK2 inhibitors was studied considering that usually the treatment of cancer is a multicomponent therapy.
The research was developed with two goals:
1. The synthesis of new Topoisomerase II inhibitors represented by molecular hybrid obtained by functionalization of planar benzoquinazolinic system substituted by methanesulfonamidoanilinic chain of Amsacrine, known drug Topo II inhibitors.
2. The synthesis of new quinolinone proteinkinase CK2 inhibitors and coumarin proteinkinase CK2 inhibitors
Synthesis of coumarin compounds as CK2 inhibitors.
No full textProtein kinase CK2 is ubiquitous, essential and highly pleiotropic kinase whose abnormally high constitutive activity is suspected to underlie its pathogenic potential in neoplasia and possible implication in viral infections. CK2 is a messenger-independent protein serine/threonine kinase with more than 300 protein substrates and is implicated in many cellular functions [1, 2]. Recently some halogen-substitute 4-methylcoumarins has shown a good biological inhibitory activity. In this work is described the synthesis of new substitute coumarins and was made a preliminary structure-activity relationship through comparison with data in literature [3]. 2 goals are persecuted: verify the importance of hydroxy group in 7 position of the 3,8-dibromo-7-hydroxy-4-methylcoumarin (DBC) [3] to maintain biological activities; study how various substituent in 4-position can influence the IC50 of literature compounds.
The structures of novel coumarin compounds as CK2 inhibitors are summarized in figure
A microwave improvement in the synthesis of the quinazoline scaffold
No full textA rapid and efficient microwave-assisted protocol is described that greatly improves a recent synthetic method developed
for quinazoline synthesis. The synthetic protocol is based on the use of cycles of microwave irradiation. The optimization process is
reported and the experimental results are compared with those of the conventional synthetic route
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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