1,721,006 research outputs found
The principal toxic glycosidic steroids in Cerbera manghas L. seeds: Identification of cerberin, neriifolin, tanghinin and deacetyltanghinin by UHPLC-HRMS/MS, quantification by UHPLC-PDA-MS
No full textThe toxicity of the sea mango (Cerbera manghas L.) is well known. The plant is ranked as one of the deadliest of the southern Asian coastline. Cardenolidic heterosides are responsible for the cardiotoxicity of trees of the Cerbera genus. We have identified and determined the concentration of the principal glycosidic steroids present in the seeds of sea mangos (Thailand). Drug screening of an extract of the seeds was carried out using ultra-high performance liquid chromatography coupled to photodiode array detection and mass spectrometry (UHPLC-PDA-MS) with quantification at 219. nm. Identification was confirmed by UHPLC-HRMS. Deacetyltanghinin (m/. z 549.3055 ± 2. ppm), neriifolin (m/. z 535.3259 ± 2. ppm), tanghinin (m/. z 591.3169 ± 2. ppm) and cerberin (577.3375 ± 2. ppm) were the most abundant glycosidic steroids present in the sea mango seeds. A seed of the dried ripe fruit had concentrations of 1209.1, 804.2, 621.4 and 285.9. μg/g, respectively. A seed of the fresh unripe fruit had concentrations of 49.4, 47.0, 3.5 and 2.3. μg/g. © 2014 Elsevier B.V
Quantification of pregabalin using hydrophilic interaction hplc-high-resolution ms in postmortem human samples: Eighteen case reports
No full textPregabalin is a drug for treating epilepsy, anxiety disorders and neuropathic pain. Cases of poisoning are rare, though some have been fatal. Concentrations of pregabalin in postmortem human samples and its distribution have very rarely been documented. As the literature is so scarce, we propose to report the concentrations in autopsy samples of 18 people who had been taking Lyrica®, including one case of a mixed overdose involving pregabalin. Analysis was carried out using an original Hydrophilic Interaction LIquid Chromatography (HILIC) technique coupled with a high-resolution mass spectrometer (m/z 160.1334 ± 5 ppm). The sensitivity of the technique enables a quick and simple treatment of the samples by protein precipitation. The method was validated in the whole blood with detection and quantification limits of 0.025 and 0.060 μg/mL, respectively. Pregabalin was a likely factor in the cause of death in 3 of the 18 cases. In the other individuals, the concentrations ranged from 0.4 to 17.0 in the peripheral blood, 1.5 to 11.1 in the central blood, 126.6 to 2004.6 in the urine and 10.5 to 58.3 μg/mL in the bile, with median values of 5.6, 4.6, 534.6 and 17.7, respectively. © The Author [2014]. Published by Oxford University Press. All rights reserved
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
Fatal intoxication due to ackee (Blighia sapida) in Suriname and French Guyana. GC-MS detection and quantification of hypoglycin-A
No full textBetween 1998 and 2001 the deaths of 16 Surinamese children were recorded along the Maroni River, which forms the border between Suriname and French Guyana. After a metabolic origin was eliminated, ethnobotanical research in the field led to a hypothesis of intoxication through the ingestion of ackee. Ackee (Blighia sapida) is a large green leafy tree of West African origin. Its unripe fruit contains large quantities of two toxic molecules: hypoglycin-A and hypoglycin-B, the former being the more toxic. We have developed a GC-MS procedure allowing us to demonstrate the presence of hypoglycin-A in the gastric fluid of one of the deceased children, and to compare the content of hypoglycin-A in fruit collected on the road to Paramaribo in Suriname (5.1. mg/g) with samples from Burkina Faso (8.1. mg/g) and Jamaica (9.2. mg/g).Field research showed the misuse of this little-known plant by Maroon witch doctors. The Bushinengue witch doctors were informed about the dangers of ackee, and no new cases have been reported to date. © 2011 Elsevier Ireland Ltd
Effetti a lungo termine della fango-balneoterapia del Bacino Termale Euganeo nella gonartrosi.
No full textDispelling 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
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