1,721,174 research outputs found
4'-Deoxypyridoxine disrupts vitamin B6 homeostasis in Escherichia coli K12 through combined inhibition of cumulative B6 uptake and PLP-dependent enzyme activity
Full text linkPyridoxal 5 '-phosphate (PLP) is the active form of vitamin B6 and a cofactor for many essential metabolic processes such as amino acid biosynthesis and one carbon metabolism. 4'-deoxypyridoxine (4dPN) is a long known B6 antimetabolite but its mechanism of action was not totally clear. By exploring different conditions in which PLP metabolism is affected in the model organism Escherichia coli K12, we showed that 4dPN cannot be used as a source of vitamin B6 as previously claimed and that it is toxic in several conditions where vitamin B6 homeostasis is affected, such as in a B6 auxotroph or in a mutant lacking the recently discovered PLP homeostasis gene, yggS. In addition, we found that 4dPN sensitivity is likely the result of multiple modes of toxicity, including inhibition of PLP-dependent enzyme activity by 4'-deoxypyridoxine phosphate (4dPNP) and inhibi-tion of cumulative pyridoxine (PN) uptake. These toxicities are largely dependent on the phosphorylation of 4dPN by pyridoxal kinase (PdxK)
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Identification of Genes Involved in Susceptibility to Biocides in Sulfate-Reducing Bacteria
No full textMicrobially induced corrosion (MIC) poses a significant challenge in various industries, leading to structural damage and economic losses due to the activity of microorganisms on metal surfaces. The major culprits of MIC are the sulfate-reducing bacteria (SRB). A common mitigation method is the usage of biocides to prevent MIC. However, the molecular mechanisms that determine susceptibility of SRB to biocides have been poorly understood. Our aim is to identify genes that are linked to biocide susceptibility in the model SRB strain Oleidesulfovibrio alaskensis (G20). We investigated the susceptibility of G20 towards three biocides commonly used in MIC protection: benzalkonium chloride (BAC), glutaraldehyde (GTA), and tetrakishydroxymethyl phosphonium sulphate (THPS). We determined selection of mutants in specific genes in two G20 barcoded transposon mutant libraries in the presence of these biocides and media as control along a concentration gradient up to 500 ppm. Our study investigated over 1843 genes in G20, revealing insights into their response to biocide treatments. We identified 1668 genes negatively affected by biocide treatment, while 175 genes showed improved fitness. Among the treatments leading to reduced fitness in the mutants, GTA had the highest number of solely negatively affected genes (186), followed by BAC (67) and THPS (69). There were common negative impacts on 280 genes of all four treatments (BAC, GTA, THPS, control). Notably, BAC and GTA shared 113 affected genes, BAC and THPS shared 59, and GTA and THPS shared 72. On the single gene level, mutants treated with THPS exhibited reduced fitness for the rluD gene (DDE_1447), encoding ribosomal large subunit pseudouridine synthase d, which plays a crucial role in protein biosynthesis. In the presence of BAC, mutants showed reduced fitness due to the lack of the acrB gene (DDE_0401), encoding a cationic efflux pump crucial for biocide resistance. Our findings provide leads for future research into the detailed molecular mechanisms that underlie biocide susceptibility in microorganisms responsible for MIC. Such detailed understanding will enable the development of improved MIC prevention strategies and foster a more sustainable use of biocides
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
