1,720,964 research outputs found
Binding of the glycopeptide antibiotic teicoplanin to D-alanyl-D-alanine-agarose: the effect of micellar aggregates.
No full textAnti-urokinase monoclonal antibody, matrix bearing it, test method, biochemical test kits which use it.
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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
Purification of single-chain urokinase precursor from A431 human epidermoid carcinoma cells by monoclonal antibody immunoaffinity chromatography.
No full textPurification procedure for bacterial translational initiation factors IF2 and IF3.
No full textIn bacteria the initiation of protein synthesis is a complex phenomenon in which specific proteins, termed initiation factors (IFs) IF1, IF2, and IF3, are involved. Notwithstanding the progress made in understanding their functions, the precise molecular mechanisms of action of these factors remain somewhat obscure. One reason for this lack of knowledge is the difficulty involved in purifying sufficient quantities of these proteins. We have developed a new procedure for purification of IFs from recombinant Escherichia coli strains producing high levels of E. coli IF3 and Bacillus stearothermophilus IF2. This new procedure is quicker than previous methods, easily scaled up to large volumes, and can be used, with only minor modifications, for different IFs. This new purification method consists essentially of one chromatographic (FPLC) separation on an ion-exchange resin (S-Sepharose fast-flow or Mono-S HR). Using this procedure we have been able to obtain chromatographically pure and biologically active preparations of both IF2 and IF3
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
Nanostructured calcium cobalt oxide Ca3Co4O9 as thermoelectric material. Effect of nanostructure on local coordination, Co charge state and thermoelectric properties
No full textThe preparation of pure Ca3Co4O9 materials in the form of dense bodies made of nano-sized grains was investigated by combining a sol-gel route, different thermal cycles, a ball-milling post-treatment and final densification with HP-FAST (High Pressure-Field Assisted Sintering). We found that an effective way for obtaining nano-sized compact bodies with only a marginal increase of the particle sizes of the original powder was the operation of HP-FAST at extremely high pressures (up to 430 MPa) and comparatively low temperatures. A ball-milling treatment before HP-FAST compaction was then required to hinder the large plastic deformation occurring when using these pressures. In contrast, un-milled powders could be densified by HP-FAST only at lower pressure and therefore required higher temperatures, thus losing their nanostructure. For all powders, X-ray absorption spectroscopy assessed a mean Co oxidation state slightly higher than III, coupled to absence of localized Co(II) and presence of localized Co(IV). Ball milling induced a decrease of the mean oxidation state of Co coupled to an increased disorder. The latter effect was confirmed by X-ray Absorption Fine Structure. Nanostructure had a complex effect on the different properties of compact bodies. According to the different conditions of HP-FAST, densities of 75–98% were achieved; the decrease in thermal conductivity was of a factor 2–3, while the electronic transport properties – in particular electrical conductivity – of nano-sized compact bodies were reduced to a larger extent with respect to their micro-sized counterparts. This demonstrates that, for bulk Ca3Co4O9 materials, nanostructure was not an effective approach toward a performing thermoelectric material
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