1,720,967 research outputs found
Catalytic and stoichiometric reactions of tertiary silanes with [Ir(Me)2Cp*L] (Cp*=h5-C5Me5; L= PMe3, PMe2Ph, PMePh2, PPh3) in the presence of one-electron oxidants. A unique case of Si-H, Si-C, Ir-C and P-F bonds one-step activation: crystal structure of [Ir(Ph)(SiPh2F)Cp*(PMe3)]
No full textThe iridium(III) dimethyl derivatives [Ir(Me)(2)Cp*L] (Cp* = eta(5)-C5Me5; L = PMe3 1a, PPh3 1d) catalyze the dehydrogenative coupling of dimethylphenylsilane in the presence of one-electron oxidants to yield Me2PhSiSiPhMe2. Compounds 1a-d react with triphenylsilane in the presence of [FeCp2]PF6 to give methane and [Ir(Ph)(SiFPh2)Cp*L] (L = PMe3 (2a), PMe2Ph (2b), PMePh2 (2c), PPh3 (2d)). 2a was structurally characterized by single-crystal X-ray diffraction experiments. The 'three-legged piano stool' coordination polyhedron is slightly deformed
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
Reduction of the NO+ ligand in half-sandwich ruthenium derivatives
No full textThe reduction of the tetrafluoroborate salts of the ruthenium nitrosyl dicationic [Ru(η5-C5R5) (NO)(L)2]2+ (R=Me, L=PMe3, 1a; PMe2Ph, 1b; R=H, L=PPh3, 2d) and monocationic complexes [Ru(Me)Cp*(NO)L]+ (L=PMe3, 3a; PMe2Ph, 3b (Cpz.ast;=η5- C5Me5) has been studied by electrochemical and spectroscopic (IR, NMR, EPR) techniques. The nitrosyl complexes 1a, 1b and 2d exhibit two successive one-electron cathodic processes due to the sequential reduction of coordinated NO+ to NO and NO-, respectively. Chemical reduction yields products of rearrangement of the intermediates which have been spectroscopically characterized. EPR studies and theoretical calculations show that in the first one-electron reduction product the electron interacts with the NO nitrogen atom and that the RuNO moiety presents significant distortion from linearity. The X-ray structure of the related [Ir(Me)2Cpz.ast;(NO)]BF4 has been determined
CK2-mediated phosphorylation of Che-1/AATF is required for its pro-proliferative activity
No full textBackground: Che-1/AATF (Che-1) is an RNA polymerase II binding protein involved in several cellular processes, including proliferation, apoptosis and response to stress. We have recently demonstrated that Che-1 is able to promote cell proliferation by sustaining global histone acetylation in multiple myeloma (MM) cells where it interacts with histone proteins and competes with HDAC class I members for binding. Methods: Site-directed Mutagenesis was performed to generate a Che-1 mutant (Che-1 3S) lacking three serine residues (Ser316, Ser320 and Ser321) in 308–325 aa region. Western blot experiments were conducted to examine the effect of depletion or over-expression of Che-1 and Che-1 3S mutant on histone acetylation, in different human cancer cell lines. Proliferation assays were assessed to estimate the change in cells number when Che-1 was over-expressed or deleted. Immunoprecipitation assays were performed to evaluate Che-1/histone H3 interaction when Ser316, Ser320 and Ser321 were removed. The involvement of CK2 kinase in Che-1 phosphorylation at these residues was analysed by in vitro kinase, 2D gel electrophoresis assays and mass spectrometry analysis. Results: Here, we confirmed that Che-1 depletion reduces cell proliferation with a concomitant general histone deacetylation in several tumor cell lines. Furthermore, we provided evidence that CK2 protein kinase phosphorylates Che-1 at Ser316, Ser320 and Ser321 and that these modifications are required for Che-1/histone H3 binding. These results improve our understanding onto the mechanisms by which Che-1 regulates histone acetylation and cell proliferation. Conclusions: Che-1 phosphorylation at Ser316, Ser320 and Ser321 by CK2 promotes the interaction with histone H3 and represents an essential requirement for Che-1 pro-proliferative ability
Establishment of high-resolution two-dimensional reference maps using 2D-DIGE technique of sheep and buffalo Milk Fat Globules
No full text- …
