1,721,032 research outputs found
Enhancement of a pentacyclic tyrosine kinase inhibitor production in Cladosporium cf. cladosporioides by Cladosporol
Full text linkThe binaphthyl derivative cladosporol A was
supplied from 60 to 200 mg l−1 to shaken cultures of Cladosporium cf. cladosporioides. Compared to blank, fungal
biomass was not affected by adding cladosporol till 100 mg l−1: it rather increased at higher ratios between 150
and 200 mg l−1. The production of the major pentacyclic metabolite 1, a cytokine production and tyrosine kinase inhibitor, was enhanced tenfold when cladosporol was
supplied at the highest ratio (200 mg l−1) to shaken growing cultures of the fungus. The bioconversion of cladosporol to cladosporol D through reductive cleavage of the epoxide group was also observed. Interest in this kind of metabolites lies in their potential activity vs DNA topoisomerase I
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
Isolation and structure elucidation of aza-sesquiterpenoids of protoilludane origin formed by shaken cultures of the fungus Clavicorona divaricata
No full textTwo novel sesquiterpenes of protoilludane origin, the alkaloids divaricatine C and D, have been isolated
from MPGB shaken cultures of the fungus Clavicorona divaricata (Basidiomycetes). Their structures were
elucidated by means of NMR studies and chemical correlations. The metabolites were weakly active
against bacteria and inhibited the germination of the water cress Lepidium sativum. A possible
mechanism of their formation from the protoilludane tsugicoline A (2) is suggested
Acremines H–N, novel prenylated polyketide metabolites produced by a strain of Acremonium byssoides
Full text linkFive novel metabolites, acremines H–N, have been isolated from malt extract–peptone–glucose agar
cultures of a strain of Acremonium byssoides. Their structures and stereochemistry were elucidated using
a combination of 13C and 1H homo and heteronuclear 2D NMR experiments. Acremines H–N inhibited
the germination of sporangia of Plasmopara viticola
Synthesis of (+)-Spirolaxine Methyl Ether
No full textA short and efficient synthesis of (+)-spirolaxine methyl ether, a metabolite of the fungus Sporotrichum laxum with inhibitory activity against Helicobacter pylori, is described. The synthesis has been carried out by a Prins cyclization, to obtain the [6,5]-spiroketal system, and a Wadsworth-Emmons condensation, applied for the installation of the polymethylene chain on the phthalide moiety
"Microbial Transformations on the Taxan Ring of 10-DAB by some Strains of the Fungus Curvularia Lunata; Formation of the bis-abeotaxanes Wallifoloil and 4-deacyl-Wallifoliol"
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