186,527 research outputs found
Organisational innovation: recruit and retain
No full textAdela McMurray, Peter ONeill, John Buckeridge and Julie Wolfram-Cox identify challenges and blockages to skills acquisition in the technical professions
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
IDENTIFICATION OF THE RESIDUES RESPONSIBLE FOR THE ALKALINE INHIBITION OF THE ACTIVITY OF CU,ZN SUPEROXIDE-DISMUTASE - A STUDY OF NATIVE AND CHEMICALLY-MODIFIED ENZYMES RID A-4573-2009
No full textThe pH dependence of the activity of Cu,Zn superoxide dismutases from bovine erythrocytes and shark liver was studied by pulse radiolysis in both the native enzymes and those chemically modified at lysine side chains. The study was aimed at identifying the residues responsible for the activity decrease at pH > 9, observed in all native Cu,Zn superoxide dismutases, and is based on the Lys --> Arg substitution present in the shark protein at position 134, which has been established to be critical for the catalytic efficiency of the enzyme. Both native enzymes display a pH dependence that can be deconvoluted by three deprotonation equilibria, at pH 9-9.5 (pK(1)), at pH 10.2 (pK(2)), and at pH 11.5 (pR(3)). pK(1) is lacking in both the modified enzymes and thus can be assigned to activity-linked lysine residues. pK(2) is clearly dominated by Arg134 in the modified shark enzyme and can be assigned to surface arginine residues. pK(3) is shared by all four enzyme forms and is likely to be due to the invariant Arg141. (C) 1995 Academic Press, Inc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
SUBSTITUTION OF ARGININE FOR LYSINE 134 ALTERS ELECTROSTATIC PARAMETERS OF THE ACTIVE-SITE IN SHARK CU,ZN SUPEROXIDE-DISMUTASE RID D-1236-2011
No full textSingle mutation at the intersubunit interface confers extra efficiency to Cu,Zn superoxide dismutase.
No full textMUTATION OF LYS-120 AND LYS-134 DRASTICALLY REDUCES THE CATALYTIC RATE OF CU,ZN SUPEROXIDE-DISMUTASE RID A-4573-2009
No full textLys-120 and Lys-134, located at the edge of the active site channel in most Cu,Zn superoxide dismutases, have been suggested to play a major role in steering the anionic substrate towards the catalytic copper ion. In this study, mutants of Xenopus laevis Cu,Zn superoxide dismutase have been engineered, with Lys-120 and Lys-134 changed into leucine and threonine, respectively, and their catalytic properties have been investigated by pulse radiolysis. Results obtained demonstrate that both residues decrease the catalytic rate by about 40%, in partial disagreement with previous brownian dynamics calculations, carried out on bovine Cu,Zn superoxide dismutase
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