1,721,006 research outputs found
Thionitrosyl- and Selenonitrosyliridium Complexes
No full textThe activation of elemental sulfur and selenium with electrophilic iridium nitride [Ir(N){N(CHCHPtBu2)2}]+ allowed the synthesis of thionitrosyl- and selenonitrosyliridium complexes. The crystallographic and spectroscopic characterization of this rare series of chalcogenonitrosyl complexes [Ir(NE){N(CHCHPtBu2)2}]+ (E = none, O, S, Se) is discussed in the context of bonding models. The experimental results indicate strong Ir-N-E multiple-bond character, in agreement with the previously proposed N-E donor-acceptor interaction as an appropriate description for the heavier chalcogens
[IrCl{N(CHCHPtBu2)2}]−: a versatile source of the IrI(PNP) pincer platform
Get PDFThe iridium(II) complex [IrCl{N(CHCHPtBu2)2}] is reduced by KC8 to give the anionic iridium(I) pincer complex [IrCl{N(CHCHPtBu2)2}]− which was isolated and fully characterized upon stabilization of the counter cation with crown ether as [K(15-cr-5)2][IrCl{N(CHCHPtBu2)2}]. This unprecedented anionic iridium(I) pincer complex completes the unusual, structurally characterized IrI/IrII/IrIII redox series [IrCl{N(CHCHPtBu2)2}]−/0/+, all in a square-planar coordination geometry, emphasizing the versatility of this PNP pincer ligand in stabilizing a broad range of oxidation states. The anionic chloro complex is a versatile source of the Ir(PNP) platform. Its reactivity was examined towards chloride ligand substitution against CO and N2, and oxidative addition of C-electrophiles, C–H bonds and dioxygen, allowing for the isolation of iridium(I) and iridium(III) (PNP) carbonyl, hydrocarbyl and peroxo complexes which were spectroscopically and crystallographically characterized
Thionitrosyl‐ and Selenonitrosyliridium Complexes
No full textThe activation of elemental sulfur and selenium with electrophilic iridium nitride [Ir(N){N(CHCHPtBu2)(2)}](+) allowed the synthesis of thionitrosyl- and selenonitrosyliridium complexes. The crystallographic and spectroscopic characterization of this rare series of chalcogenonitrosyl complexes [Ir(NE){N(CHCHPtBu2)(2)}](+) (E = none, O, S, Se) is discussed in the context of bonding models. The experimental results indicate strong Ir-N-E multiple-bond character, in agreement with the previously proposed N-E donor-acceptor interaction as an appropriate description for the heavier chalcogens
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
Biomechanical comparison of four double-row speed-bridging rotator cuff repair techniques with or without medial or lateral row enhancement
No full textBiomechanical comparison of four different Speed-Bridge configurations with or without medial or lateral row reinforcement. Reinforcement of the knotless Speed-Bridge double-row repair technique with additional medial mattress- or lateral single-stitches was hypothesized to improve biomechanical repair stability at time zero. Controlled laboratory study: In 36 porcine fresh-frozen shoulders, the infraspinatus tendons were dissected and shoulders were randomized to four groups: (1) Speed-Bridge technique with single tendon perforation per anchor (STP); (2) Speed-Bridge technique with double tendon perforation per anchor (DTP); (3) Speed-Bridge technique with medial mattress-stitch reinforcement (MMS); (4) Speed-Bridge technique with lateral single-stitch reinforcement (LSS). All repairs were cyclically loaded from 10-60 N up to 10-200 N (20 N stepwise increase) using a material testing device. Forces at 3 and 5 mm gap formation, mode of failure and maximum load to failure were recorded. The MMS-technique with double tendon perforation showed significantly higher ultimate tensile strength (338.9 +/- A 90.0 N) than DTP (228.3 +/- A 99.9 N), LSS (188.9 +/- A 62.5 N) and STP-technique (122.2 +/- A 33.8 N). Furthermore, the MMS-technique provided increased maximal force resistance until 3 and 5 mm gap formation (3 mm: 77.8 +/- A 18.6 N; 5 mm: 113.3 +/- A 36.1 N) compared with LSS, DTP and STP (P < 0.05 for each 3 and 5 mm gap formation). Failure mode was medial row defect by tendon sawing first, then laterally. No anchor pullout occurred. Double tendon perforation per anchor and additional medial mattress stitches significantly enhance biomechanical construct stability at time zero in this ex vivo model when compared with the all-knotless Speed-Bridge rotator cuff repair
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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