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The carbon monoxide derivative of human hemoglobin carrying the double mutation LeuB10->Tyr and HisE7->Gln on alpha and beta chains probed by infrared spectroscopy
No full textThe fine structural properties of the distal heme pocket have been probed by infrared spectroscopy of ferrous carbon monoxy human hemoglobin mutants carrying the mutations LeuB10-->Tyr and HisE7-->Gln on the alpha, beta, and both chains, respectively. The stretching frequency of iron-bound carbon monoxide occurs as a single broad band around 1943 cm(-1) in both the alpha and the beta mutated chains. Such a frequency value indicates that no direct hydrogen bonding exists between the bound CO molecule and the TyrB10 phenolic oxygen, at variance with other naturally occurring TyrB10, GlnE7 nonvertebrate hemoglobins. The rates of carbon monoxide release have been determined for the first time by a Fourier transform infrared spectroscopy stopped-flow technique that allowed us to single out the heterogeneity in the kinetics of CO release in the alpha and beta chains for the mutated proteins and for native HbA. The rates of CO release are 15- to 20-fold faster for the mutated alpha or beta chains with respect to the native ones consistent with the lack of distal stabilization on the iron-bound CO molecule. The present results demonstrate that residues in key topological positions (namely E7 and B10) for the distal steric control of the iron-bound ligand are not interchangeable among hemoglobins from different species
Septic complications involving hand and wrist in patients with pre-existing rheumatoid arthritis: The role of magnetic resonance imaging and sonography
No full textPurpose: Septic arthritis (SA), frequently involving hand and wrist, is common in rheumatoid arthritis (RA) patients due to immunomediated etiology of RA and immunosuppressive drug use. Clinical and laboratory features might not be useful to differentiate between RA relapse and superimposed SA. The role of magnetic resonance imaging (MRI) has been described in several studies. Our aim is to evaluate the role of ultrasonography (US). Material and methods: In the last 4 years 31 MRI of hand and wrist has been performed in the suspect of SA complicating RA. A 1.5. T unit (Siemens Symphony, Erlangen, Germany) with standardized protocol, involving the administration of contrast medium, was used. Also US with power Doppler evaluation was performed. A Philips IU22 US scanner was used. Results: Eleven points (according to Graif's study) were analyzed for every MRI and US. At MRI joint effusion (37.5% of RA relapse vs 100% superimposed SA) and soft tissue edema (25% vs 100%) were indicative of SA. At US joint effusion (31.3% of RA relapse vs 73.3% superimposed SA) and soft tissue edema (12.5% vs 60%) were indicative of SA. Conclusion: Our results suggest that joint effusion and soft tissue edema are markers suggestive for superimposed SA and that MRI is more sensitive in their evaluation. Although US is less sensitive than MRI, the former is important in guiding invasive procedure and evaluating patients that cannot undergo MRI. © 2012 Elsevier Srl
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
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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