1,721,016 research outputs found
Ferrate(ii) complexes with redox-active formazanate ligands
Full text linkThe synthesis of mono(formazanate) iron complexes is described. In the presence of tetrabutylammonium halides, salt metathesis reactions afford the ferrate(ii) complexes [Bu4N][LFeX2] (L = PhNNC(p-tol)NNPh; X = Cl, Br) in good yield, and the products are characterized in detail. The high-spin ferrate(ii) complexes show cyclic voltammograms that are consistent with reversible, ligand-based one-electron reduction. The halides in these ferrate(ii) compounds are labile, and are displaced by 4-methoxyphenyl isocyanide (4 equiv.) as evidenced by formation of the low-spin, cationic octahedral complex [LFe(CNC6H4(p-OMe))4][Br]. Thus, a straightforward route to mono(formazanate) iron(ii) complexes is established
Palladium alkyl complexes with a formazanate ligand: synthesis, structure and reactivity
Full text linkPalladium(ii) complexes with a bidentate, anionic formazanate ligand are described. Attempts to prepare mono(formazanate) palladium alkyl complexes often leads to the homoleptic bis(formazanate) complex, which shows rich electrochemistry due to the redox-active nature of the ligands. Performing salt metathesis between the precursor [Pd(COD)(CH3)Cl] and the potassium salt of the ligand in the presence of tetrabutylammonium chloride yields a square planar mono(formazanate) palladate complex through coordination of chloride anion. Ligand exchange allows binding of unsaturated molecules and evaluation of the reactivity of the Pd-CH3 fragment. Using this approach, insertion reactions of CO, isocyanide and methyl acrylate into the Pd-CH3 bond are demonstrated
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
Fluorinated and Charged Hydrogenated Alkanethiolates Grafted on Gold: Expanding the Diversity of Mixed-Monolayer Nanoparticles for Biological Applications
Full text linkLow intrinsic toxicity, high solubility, and stability are important and necessary features of gold nanoparticles to be used in the biomedical field. In this context, charged nanoparticles proved to be very versatile, and among them charged mixed-monolayer gold nanoparticles, displaying monolayers with well-defined morphologies, represent a paradigm. By using mixtures of hydrogenated and fluorinated thiols, the formation of monolayer domains may be brought to an extreme because of the immiscibility of fluorinated and hydrogenated chains. Following this rationale, mixed monolayer gold nanoparticles featuring ammonium, sulfonate, or carboxylic groups on their surface were prepared by using amphiphilic hydrogenated thiols and 1H,1H,2H,2H-perfluoro-alkanethiols. The toxicity of these systems was assessed in HeLa cells and was found to be, in general, low even for the cationic nanoparticles which usually show a high cytotoxicity and is comparable to that of homoligand gold nanoparticles displaying amphiphilic charge neutral hydrogenated or fluorinated thiolates in their monolayer. These properties make the mixed ligand monolayer gold nanoparticles an interesting new candidate for medical application
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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