1,720,959 research outputs found
An experimental and theoretical study of metallorganic coordination networks of tetrahydroxyquinone on Cu(111)
No full textThe adsorption of tetrahydroxyquinone (THQ) on the Cu(111) surface at different temperatures gives rise to different ordered structures, unveiled by density functional theory (DFT) modelling of scanning tunnelling microscopy (STM) topography and by X-ray absorption spectroscopy (XAS) measurements. After annealing, the THQ films generated tetrameric Cu clusters embedded in a metal–organic tetraoxyquinone (TOQ) network, whose electronic properties were thoroughly studied. The remarkable agreement between the STM results and periodic calculations was exploited to model C and O K-edge XA spectra recorded before (room temperature, RT) and after annealing (high temperature, HT). The subsequent analysis of the C and O TOQ@Cu(111) K-edge XA spectra provides definitive information about the structural arrangement of the TOQ@Cu(111) coordination network, confirming the complete THQ dehydrogenation upon annealing, suggested by the simulations of the STM images. The obtained information is crucial to rationalize the evolution of THQ@Cu(111) upon heating, shedding light into the potential reactivity of the HT coordination network, and, more generally, to investigate the nature and character of low-lying virtual states, the most involved states in the chemical reactions
Substrate involvement in dioxygen bond dissociation catalysed by iron phthalocyanine supported on Ag(100)
No full textDioxygen adsorbs in the end-on configuration on-top of the Fe atoms of an iron phthalocyanine monolayer supported on Ag(100) and is partly cleaved at room temperature to produce O/FePc/Ag(100). Scanning tunnelling microscopy coupled to density functional theory calculations gives the first experimental evidence of the substrate involvement in the O2 bond dissociation
Unfolding IGDQ Peptides for Engineering Motogenic Interfaces
Full text linkExtracellular matrix (ECM)-mimicking surfaces are pivotal tools in understanding adherent cell physiopathology. In this sense, we have recently reported on a discrete set of ECM-mimicking SAMs, among which only those exposing IGDQ peptide-alkanethiols sustain the adhesion of MDA-MB-231 cells by triggering FAK phosphorylation and peculiarly induce the migration of individual cancer cells on the subcentimeter scale. Starting from the experimentally observed relationship among the SAM composition, organization, and biological response, a systematic computational characterization aided in pinpointing the atomistic details through which specific composition and organization achieve the desired biological responsiveness. Specifically, the solvent, number and type of peptides, and presence or absence of surface fillers were accurately considered, creating representative model SAMs simulated by means of classical molecular dynamics (MD) with a view toward unravelling the experimental evidence, revealing how the conformational and structural features of these substrates dictate the specific motogenic responses. Through complementary experimental and computational investigations, it clearly emerges that there exists a distinct and precise mutual interaction among IGDQ-peptides, the surface fillers, and Au, which controls the structural properties of the ECM-mimicking SAMs and thus their motogenic potential.</p
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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