1,721,040 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
Mutationen bei primären Mitochondropathien und multiple Deletionen der mitochondrialen DNA bei idiopathischen inflammatorischen Myopathien
No full textIn this study I detected deletions in the mitochondrial genome of patients with idiopathic inflammatory myopathies using long distance PCR and sequencing techniques. The deletions found are unusually large (ca. 10500-12800 bp) and show uncommon 5'-breakpoints between nt800 and nt3326 in the "minor region" of the genome. The atypical location of these deletions suggests a different pathomechanism. The impact of the mitochondrial DNA deletions in the pathogenetic cascade remains uncertain. The mtDNA of a patient whose symptoms seemed to fit to the Kearn-Sayres-Syndrom was also screened using the long distance PCR. Multiple deletions were found and some of them sequenced. The diagnosis KSS could therefore be confermed. The secondary LHON-Mutation A4917G was also found in this patient. The LHON-mutation G3460A was identified in two healthy members (mother and daughter) of a family suffering from LHON. The mutation was sequenced and quantified (100%) using restriction methods. I tried to estimate the lifetime-risk of mother and daughter to become symptomatic. There was no evidence that the dilatative cardiomyopathy also frequent in this familiy was due to mitochondrial deletions. Furthermore I developed restriction tests for the screening of the frequent mitochondrial diseases MERRF, MELAS and M.Leigh and tested several patients using those tools
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
Proteinchemische Charakterisierung und Kristallisation der caa 3 -Cytochrom-c-Oxidase aus Thermus thermophilus
No full textUntersuchungen zur Anbindung von Proteinen und Peptiden an Biomaterialien sowie zur Schädigung dieser Proteine und Peptide durch reaktive Sauerstoff-Spezies
No full textBiomaterials in direct contact to body tissues may lead to inflammatory reactions with the possible formation of reactive molecule species. The extent of these reactions depends decisively on the property of the surface of the particular biomaterial which can be modified in a positive manner by means of the covalent coupling of physiologically active proteins and peptides. In this context the covalent coupling of proteins to biomaterial surfaces as well as the damage to proteins due to reactive molecule species was investigated: - the covalent coupling of different proteins and peptides to the surface of functionalised TiAl6V4 and Si3N4 as well as to the surface of polylactic acid plastic film grafted with polyacrylic acid was examined: at the surface of TiAl6V4 and Si3N4 about 70 molecules of horse radish peroxidase per 1 µm² could be covalently bound, whereas to the grafted polylactic acid plastic film about 25*105 molecules per 1 µm² could be bound. Experiments with further proteins show a correlation between the number of bound molecules and their size. - for the reactions of reactive molecule species with proteins 3-nitrotyrosine was chosen as a sensitive marker and an assay was established: after pre-column derivatisation with dimethylaminoazobenzenesulfonyl chloride (DABS-Cl) and subsequent analysis via High Performance Liquid Chromatography (HPLC) a detection limit in the lower pmol range could be achieved. For the quantification of even smaller amounts of 3-nitrotyrosine an enzyme linked immunosorbent assay (ELISA) with polyclonal antibodies was deve
Untersuchungen zur Anbindung von Proteinen und Peptiden an Biomaterialien sowie zur Schädigung dieser Proteine und Peptide durch reaktive Sauerstoff-Spezies
No full textBiomaterials in direct contact to body tissues may lead to inflammatory reactions with the possible formation of reactive molecule species. The extent of these reactions depends decisively on the property of the surface of the particular biomaterial which can be modified in a positive manner by means of the covalent coupling of physiologically active proteins and peptides. In this context the covalent coupling of proteins to biomaterial surfaces as well as the damage to proteins due to reactive molecule species was investigated: - the covalent coupling of different proteins and peptides to the surface of functionalised TiAl6V4 and Si3N4 as well as to the surface of polylactic acid plastic film grafted with polyacrylic acid was examined: at the surface of TiAl6V4 and Si3N4 about 70 molecules of horse radish peroxidase per 1 µm² could be covalently bound, whereas to the grafted polylactic acid plastic film about 25*105 molecules per 1 µm² could be bound. Experiments with further proteins show a correlation between the number of bound molecules and their size. - for the reactions of reactive molecule species with proteins 3-nitrotyrosine was chosen as a sensitive marker and an assay was established: after pre-column derivatisation with dimethylaminoazobenzenesulfonyl chloride (DABS-Cl) and subsequent analysis via High Performance Liquid Chromatography (HPLC) a detection limit in the lower pmol range could be achieved. For the quantification of even smaller amounts of 3-nitrotyrosine an enzyme linked immunosorbent assay (ELISA) with polyclonal antibodies was deve
Mitochondriale Zytopathien : Aufarbeitung der unterschiedlichen Pathogenese ausgewählter mitochondrialer Zytopathien anhand von zwei Fallbeispielen
No full textMitochondrial cytopathies are a heterogeneous group of diseases with a pathogenesis which is still not completely understood. This paper shows the heterogeneity of mitochondrial diseases on the basis of two clinical cases, the problem of their clinical interpretation and the unanswered questions concerning their pathogenesis. Therefore the mitochondrial dna of the two patients is analyzed by molecular genetic methods. The results are discussed concerning the clinical, pathoanatomical and molecular biological findings. Because of this approach a special question is raised for each patient's special findings. The first case is a patient suffering from LHON with a lymphoma, who needed chemotherapy. Due to the preliminary damaged mitochondria we were afraid of a higher risk the therapy could cause, mainly because apoptosis is discussed in the pathogenesis of LHON. In order to estimate this risk the clinical diagnosis LHON has to be ensured by molecular genetic examinations. The effects of the chemotherapy were carefully clinically monitored and tested in vitro. As a conclusion the influence of the detected mutations on the cells' sensitivity for cytostatic drugs should be evaluated. The second case shows immunhistochemical signs of a Becker's muscular dystrophy, but histological, electron microscopical and biochemical signs for a mitochondrial myopathy. Damages in the mitochondrial dna shall be found to explain the different findings. Again the connection between the mitochondrial dna alterations, the histological findings and the clinical symptoms is of great importance. Finally an overview of the assumed pathogenesis is given by literature research
Proteinchemische Charakterisierung und Kristallisation der caa 3 -Cytochrom-c-Oxidase aus Thermus thermophilus
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