1,721,090 research outputs found
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
Synthesis, characterization and X-ray structural studies of three hybrid inorganic-organic compounds: Silver(I)-, lead(II)- and tris(phenanthroline) copper(II)-2,6-naphthalenedisulfonate (2,6-nds)
No full textThree new hybrid inorganic-organic compounds of silver(I), Ag2(2,6-nds), 1, lead(II), [Pb(2,6-nds)·H2O]n, 2 and copper(II), [Cu(phen)3](2,6-nds)·11H2O, 3, have been synthesized by reacting appropriate reactants in aqueous medium. All the three compounds were characterized on the basis of elemental analyses, spectroscopic techniques (FT-IR, NMR, EPR and NIR-Vis-UV), thermogravimetric analyses and X-ray powder diffraction studies. Single crystal X-ray structure determination of compound 2 (Monoclinic, P 21/c) revealed a polymeric structure in which lead(II) is seven coordinated by six sulfonato oxygen atoms and one oxygen atom of water molecule where as compound 3 (Triclinic, P1 ̄) revealed the existence of discrete ions i.e. [Cu(phen)3]2+ cation, 2,6-naphthalenedisulfonate (2,6-nds) anion and eleven water molecules of crystallization. These water molecules in wide channels show intermolecular non-covalent interactions with disulfonate anion and [Cu(phen)3]2+ cationic layer, leading to crystal lattice stabilization. The d-d bands found in diffuse-reflectance electronic spectrum arise from 2A1g (dx2-y2) > 2A2g (dz2) ≈ 2B1g (dxy) > 2B2g (dxy) ≈ 2B3g (dyz) transitions. A rare resolution of copper hyperfine splitting of powder EPR spectrum is observed only at low temperature
Copper(II) diclofenac complexes: Synthesis, structural studies and interaction with albumins and calf-thymus DNA
No full textThe reaction of the copper(II) diclofenac complex [Cu(dicl)2(H2O)2] (1) (dicl = deprotonated diclofenac (Hdicl)) with the chelating N-donor ligands ethylenediamine (en), propan-1,3-diamine (pn), unsymmetrical dimethylethylene-diamine (unsym-dmen) and N,N,N',N'-tetramethylethylene-diamine (temed) in methanol-water (4:1 v/v) yielded the novel copper(II) complexes [Cu(en)2(H2O)2](dicl)2·2H2O (2), [Cu(pn)2(H2O)2](dicl)2·2H2O (3), [Cu(unsym-dmen)2(H2O)](dicl)2·H2O (4) and [Cu(temed)(dicl)2] (5), respectively. All the synthesized complexes were characterized by spectroscopic (UV-vis, FT-IR) methods. The structures of complexes 2, 3 and 5 were unambiguously determined by single-crystal X-ray crystallography. X-ray structures of complexes clearly revealed the ionic structure of complexes 2, 3 and the covalent structure of complex 5. The geometry of complex 4 was optimized by Density Functional Theory (DFT) calculations. The ability of the complexes 1-5 to bind to calf-thymus DNA was monitored in vitro by diverse techniques (UV-vis spectroscopy, cyclic voltammetry, viscosity measurements) and via competitive studies with ethidium bromide. The interaction of complexes 1-5 with bovine serum albumin was studied in vitro by fluorescence emission spectroscopy and the corresponding binding constants were calculated. The biological behavior of complexes 1-5 was compared with previously reported Cu(II), Mn(II) and Ni(II) complexes of diclofenac
Coordination complexes of copper(II) with herbicide-trichlorophenoxyacetate: Syntheses, characterization, single crystal X-ray structure and packing analyses of monomeric [Cu(γ-pic)3(2,4,5-trichlorophenoxyacetate)]·H2O, [trans-Cu(en)2(2,4,5-trichlorophenoxyacetate)2]·2H2O and dimeric [Cu2(H2tea)2(2,4,5-trichlorophenoxyacetate)2]·2(H2O)
No full textThree novel coordination complexes of copper(II) with 2,4,5-trichlorophenoxyacetate [Cu(γ-pic)3(L)2]·H2O 1, [trans-Cu(en)2(L)2]·2H2O 2 and [Cu2(H2tea)2(L)2]·2H2O 3, where L = 2,4,5-trichlorophenoxyacetate, γ-pic = γ-picoline, en = ethylenediamine, H2tea = monodeprotonated triethanolamine, were synthesized by addition of γ-picoline/ethylenediamine/triethanolamine, respectively, to the hydrated Cu(2,4,5-trichlorophenoxyacetate)2 suspended in methanol-water (4:1, v/v). The newly synthesized complexes have been characterized by elemental analyses, spectroscopic techniques (UV–Vis and FT-IR), magnetic moment determination, molar conductance studies, TGA and single crystal X-ray diffraction method. The structure determination revealed neutral nature of complexes in all the three cases, with different coordination geometry around the copper(II) metal centre depending upon nature of the N- or N,O-donor ligands. Hydrogen bonding network i.e. O–H⋯O and C–H⋯O in complexes 1, 3 and N–H⋯O, and O–H⋯O in complex 2 stabilizes crystal lattice in copper(II) complexes besides other non-covalent interactions
New copper(II) complexes of the anti-inflammatory drug mefenamic acid: A concerted study including synthesis, physicochemical characterization and their biological evaluation
No full textReaction of hydrated copper(ii) mefenamate in the presence of diverse N-donor ligands such as N,N,N′,N′-tetramethylethylenediamine (temed), ethylenediamine (en), β-picoline (β-pic) in a methanol:water mixture (4:1, v/v) yielded crystalline monomeric copper(ii) complexes [Cu(temed) (mefenamato)2], 1, [Cu(en)2(H2O)2](mefenamato)2, 2 and [Cu(β-pic)2(mefenamato)2]·H2O, 3. The newly synthesized complexes have been characterized by elemental analysis, spectroscopic methods (FT-IR, UV-Vis and EPR), thermogravimetric analyses and single-crystal X-ray structure determination in the case of complexes 2 and 3. The ground-state geometry optimization of complex 1 was performed by DFT calculations. In order to verify the complexes capability to get bound and possibly transported by the albumin towards their biological targets (cells and/or tissues), the interaction with bovine (BSA) and human serum albumin (HSA) was studied by fluorescence emission spectroscopy. The interaction of complexes 1-3 with calf-thymus DNA (CT DNA) was monitored by UV-Vis spectroscopy, cyclic voltammetry, viscosity measurements and via the ethidium bromide (EB) displacement from the EB-DNA conjugate performed by fluorescence emission spectroscopy, as a preliminary approach to evaluate their potential biological activity
Synthesis and characterization of new silver(I) naphthalenedisulfonate complexes with heterocyclic N-donor ligands: Packing analyses and antibacterial studies
No full textFour new silver(I) naphthalenedisulphonate complexes, [Ag 2 (1,5-nds) (β-Pic) 4 ]·2H 2 O (1), [Ag 2 (1,5-nds)(γ-Pic) 4 ]·6H 2 O (2), [Ag 2 (2,6-nds) (β-Pic) 4 ] (3) and [Ag 2 (2,6-nds) (γ-Pic) 4 ]·2H 2 O (4) have been synthesized using appropriate starting materials at ambient temperature and normal reaction conditions and fully characterized by spectroscopic methods (FT-IR, NMR). The structures of all the four complexes were determined using single crystal X-ray diffraction techniques and a detailed analysis of the role of weak non-covalent interactions in the solid state (hydrogen bonds, argentophylic interactions, π⋯π interactions) were investigated. Antibacterial activities of all complexes have been evaluated, indicating their high efficacy against both gram positive and gram negative bacterial strains
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