1,720,978 research outputs found
The Unique 6-(p-Hydroxyphenyl)-2H-3,4-Dihydro-1,1-Dioxo-1,4-Thiazine and the New Tripeptide L-Glu-Gly-4-Hydroxystirylamine from the Marine Sponge Anchinoe tenacior
No full textIn our continuing search for bioactive compounds from marine organisms, we reported previously the isolation of a dimeric peptide alkaloid, anchinopeptolide A, from the Mediterranean sponge Anchinoe tenacior. Here we describe the isolation and structure elucidation of an unique metabolite 1, which incorporates a 1,1-dioxo-1,4 thiazine ring, and of a new tripeptide(2), from the sponge A. tenacior
A Dimeric Peptide Alkaloid of a Completely New Type, Anchinopeptolide A, from the Marine Sponge Anchinoe tenacior
No full textAnchinopeptolide A (1). a dimeric peptide alkaloid of a completely new type, has been isolated from the marine sponge
Anchinoe tenacior collected in the Mediterranean sea along the coasts of Tunisia. The structure elucidation of 1, which include in each half aC-terminal trans4-hydroxyystirylammino residue linked to L-alanine, which in turn is attached to an arginine derived 5-guanidino-2-hydroxy-pentanoyl residue, is described
Four New Dimeric Peptide Alkaloids, Anchinopeptolides B-D, and Cycloanchinopeptolide C, Congeners of Anchinopeptolide A, from the Mediterranean Marine Sponge Anchinoe tenacior
No full textPhosphated and sulfated marine polyhydroxylated steroids from the starfish Tremaster novaecaledoniae
No full textBeside tremasterols A-C, the first phosphated steroid glycosides to be found from a natural source, the starfish Tremaster novaecaledoniae contains nine more novel steroid constituents. One, is related to the previous tremasterols by having the same 6-O-phosphated function. A second group of 4 compds. possesses the same 3,6-disulfated 3β,6α-(22R)-trihydroxycholestane structure, differing by the presence of the Δ9(11) double bond in 2 compds. and by the acetate conjugation of the 22-hydroxyl group in the 2 other compds. The remaining 4 compds. are highly hydroxylated steroids, including one that features the cis A/B ring junction, never encountered before among steroids derived from starfishes
Starfish saponins. VI. Unique 22,23-epoxysteroidal cyclic glycosides, minor constituents from Echinaster sepositus.
No full text
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
- …
