1,720,970 research outputs found
Ceramic surfaces with microbiological action for healthcare buildings
No full textIn the present study, porcelain stoneware tile samples, having a silver doped surface, with antibacterial characteristics, were prepared. The microstructure of the fired samples was studied with the aid of a scanning electron microscope, equipped with an energy dispersion X-ray attachment. Vickers hardness and surface roughness were also assessed. The presence of silver does not meaningfully change the physical and mechanical characteristics of the standard and silver added surfaces. The antibacterial activity against Escherichia coli (E. coli, ATCC 25922) was examined, setting up a methodology useful for hard surfaces. The achieved results allowed to identify the main processing problems of such body mixes, modified with silver, for a possible future industrial developments
Complete Assignment of the Aliphatic Chains in Dimers, Trimers and Polymer of 3-Hexylthiophene through 2D-NMR Spectroscopy
No full textThe 1-H and 13-C signals of the hexyl chains of the title compounds were fully assigned. The regiochemical features of the aliphatic region of proron and carbon spectra were analysed in dimers and trimers
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
Synthesis and antimuscarinic activity of some N-(4-dimethylaminomethyl-2-phenyl-1,3)dioxolan-2-ylmethyl)lactam methiodides
No full textA series of 1,3-dioxolane-based ligands, having a lactam function were synthesized and tested as potential muscarinic antagonists. The compounds display moderate affinity for the three receptor subtypes M1-M3, with significant selectivity for the M1-M3 over the M2 subtype
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
Separation of alpha-adrenergic and imidazoline/guanidinium receptive sites 4IGRS) activity in a series of imidazoline analogues of cirazoline
No full textTo characterize the structure-activity relationship between alpha(1)-adrenergic receptors and the family of imidazoline/guanidinium receptive sites (IGRS), we synthesized and characterized a series of analogues of cirazoline, an imidazoline with high affinity for alpha(1)-adrenergic receptors and IGRS. Analysis of potency, affinity and efficacy of the synthesized molecules indicate different structure-activity relationships for IGRS and alpha-adrenergic receptors. Cirazoline exhibits a 25-fold higher affinity for IGRS (pK(i) 7.9) than for alpha(1)-adrenergic receptors. Replacement of the cyclopropyl ring with an isopropoxy group resulted in a molecule that was 20-fold more selective for alpha(1)-adrenergic receptors than for IGRS, i.e. a 500-fold increase in selectivity relative to cirazoline. The unsubstituted derivative 3 and the methyl and allyl substituted analogues 4 and 12 are of particular interest: compounds 3 and 4 recognize IGRS with high affinity (pK(i) 7.83 and 8.17) and high selectivity (398 and 123) with respect to the alpha(1)-adrenergic receptor; compound 12 also recognizes IGRS with high affinity (pK(i) 8.08) and high selectivity (228 and 138) with respect to the alpha(2B), and alpha 2(C)-adrenergic receptor subtypes. Thanks to their IGRS selectivity, these compounds represent novel and valuable pharmacological tools for the characterization and elucidation of the physiological role of these novel sites
Multinuclear NMR spectroscopy structural properties of ofloxacin
No full textAn accurate 1-H, 13-C and 15-N NMR study on ofloxacin 1 is reported. The conformational properties of the two mobile regions (the benzoxazine and the piperazinyl ring) are studied and discussed. According to the spectroscopic data, the condensed benzoxazine ring shows a conformational consistent with the C-2 atom below the mean molecular plane and the 3-CH3 group in a pseudo-axial position and the piperazinyl group maintains a conformational favourable to N-1' conjugation with the aromatic ring. How multinuclear NMR spectroscopic studies may impact on biological activity and SAR investigations is discussed
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