1,720,958 research outputs found
Bis(dimethylsulfoxide)carbonateplatinum(II), a new synthon for a low-impact, versatile synthetic route to anticancer Pt carboxylates
No full textThe work describes a new low-impact synthetic route to Pt(ii)-carboxylate complexes, a class of compounds provided with established anticancer activity. The process is based on the ligand substitution on [PtCO3(Me2SO-S)2] (1), a new synthon that can be easily prepared in water with high yield, is stable as a solid, and is reactive in solution where all its ligands can be easily replaced. It reacts with acidic O-donors releasing CO2 as the only side-product, whose development also supplies a driving force toward the products. The substitution of carbonate led to new Pt-DMSO carboxylate complexes 2-4, while the total substitution of the ligands of complex 1 gave new Pt-phosphino carboxylates 5-9 in high yields. The X-ray crystal structures of complexes [Pt(d(-)-quinate-O,O′)(Me2SO-S)2] (3), [Pt(salicylate)(Me2SO-S)2] (4) and [Pt(salicylate)(PPh3)2] (6) were determined. The tests of the antiproliferative activity of complexes 1-9 on two human tumoral cell lines, A2780 (cisplatin-sensitive) and SKOV-3 (cisplatin-resistant), showed that the PTA (PTA = 1,3,5-triaza-7-phosphaadamantane) complexes 7-9 were the most active on both cell lines
Synthesis and characterization of Pt complexes containing dichloroacetate (DCA), designed for dual anticancer action
No full textA group of new Pt(II) complexes with dichloroacetate (DCA), bearing DMSO (cis-[Pt(DCA)2(Me2SO-S)2], 2) or phosphines (cis-[Pt(DCA)2(PPh3)(Me2SO-S)], 3, cis-[Pt(DCA)2(P)2], P = PPh33a, P = PTA 4a and [Pt(DCA)(P)3]DCA, P = PPh33b, P = PTA, 4b) as neutral ligands was prepared by a simple fast route from the inorganic synthon [PtCO3(Me2SO-S)2], 1. The X-ray crystal structures of 2, 3, 3a and 4a were determined. The antiproliferative activity of 2, 4a, and 4b was evaluated against two human cancer cell lines, cisplatin sensitive A2780 and cisplatin resistant SKOV-3, and the results were compared with known amine analogues and with the dichloride precursors
SPR-based non-invasive prenatal testing for fetal sex determination
No full textSince the discovery of cell-free fetal DNA (cffDNA) in maternal plasma, diagnostic non-invasive prenatal methods have been developed and optimized for fetal sex determination and identification of genetic diseases. As far as fetal sex determination, this might be important for therapeutic intervention on sex-associated pathologies. Biosensors based on surface plasmon resonance (SPR), such as BiacoreTM X100, might be available for these studies. In fact, SPR biosensors permit to monitor the interactions between biomolecules in real-time, providing both qualitative and quantitative information, through kinetics, affinity and concentration analyses. In this study BiacoreTM X100 has been applied to identify the Y-chromosome in cffDNA obtained from plasma samples of 27 pregnant women at different gestational ages. We have performed SPR-based analysis of SRY-PCR products using a BiacoreTM instrument and an SRY-specific probe immobilized on the sensor chip. The results suggest that there is a statistically significant difference between samples collected by pregnancies carrying male or female fetuses. Moreover cffDNA, obtained at early gestational ages (6th-7th week) and not detectable by conventional quantitative real-time PCR, might be discriminated with high accuracy and reliability using SPR-based biosensors
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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