1,720,971 research outputs found
Determination of some quinolones in tablets, human plasma and urine by differential-pulse polarography
No full textA differential pulse polarographic method was developed for the determination of norfloxacin, cinoxacin and pipemidic. oxolinic and piromidic acids in tablets and biological fluids. Well defined peaks, useful for an accurate and precise assay, were observed in the appropriate supporting electrolyte (Britton-Robinson and phosphate buffers), depending on both the kind of preparation (tablet, plasma or urine) and the quinolone investigated. The analysis of quinolones in biological fluids requires a prior clean-up procedure (treatment with acetonitrile and 2 M potassium hydroxide for plasma and solid-liquid extraction for urine) while common excipients were found not to interfere in the tablet assay. In each of the above situations (tablet, plasma or urine), good precision of the method evaluated as the CV, was found. © 1994
Thin layer chromatography in the quantitative analysis of pharmaceuticals. Comparison of layers in the analysis of complex mixtures of phenothiazine derivatives
No full textMicrospectrophotometric evaluation of digestibility of pollen grains
No full textDigestibility of pollen grains of poppy (Papaver rhoeas) and hazelnut (Corylus avellana) subjected to a human-like in vitro digestion with pancreatic enzymes was evaluated. Pollens showed different types of walls. Digestibility was determined for total protein and insoluble carbohydrate contents by means of a new application of microspectrophotometry. Results demonstrated that pollen grains of both species were only partly digested; after 24 h treatment, only 26% of carbohydrates and 48% of proteins were digested in poppy and only 3% and 59% in hazelnut. This is probably due to the difficulty of enzymes to penetrate the intine of pollen grains. The degree of digestion of insoluble carbohydrates varied in the studied species according to their chemical nature and their storage sites
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
Ligand-macromolecule complexes: affinity index determination by selective nuclear relaxation analysis
No full textProton NMR selective and non-selective spin-lattice relaxation rate measurements were used to monitor the strength of the overall complexation behaviour of a ligand (carbamazepine) toward a macromolecular receptor (albumin). The 'affinity index,' a quantitative parameter related to the strength of the ligand-macromolecule interaction, was determined from the experimental contribution of the bound ligand molar fraction to the observed selective spin-lattice relaxation rate. The effect of a second ligand (lamotrigine) on the carbamazepine-albumin interaction was also investigated and was found to have a modulation effect on the carbamazepine-albumin interaction. Copyright (C) 2001 John Wiley & Sons, Ltd
Identification and determination of the hydrolysis products of pirenzepine. Note I [Comportamento idrolitico della pirenzepina identificazione e valutazione dei prodotti di idrolisi. Nota I]
No full textHydrolytic process of pirenzepine were studied. Together with 5,11-dihydro-6H-pirydo[2,3-b] [1,4]benzodiazepin-6-one other compounds were identified. The single compounds were evaluated by densitometric methods
Picrocrocin and crocetin content in four clones of saffron (Crocus sativus L. - Iridaceae) and some other species of the genus Crocus
No full textQuantitative variation of the main carotenoids in Italian tomatoes in relation to geographic locations, harvesting time, varieties and ripening stages
No full textThe aim of this study was to evaluate if the carotenoid content of Italian tomatoes is affected by factors such as the geographical area in which the plants are cultivated, harvest time, tomato typology and ripening stage. Three Italian tomato varieties were sampled in different geographical locations throughout Italy in the summer and winter months. Significant differences were found in the lycopene, beta-carotene and phytoene contents as a function of tomato variety with the highest carotenoid levels recorded for cherry tomatoes. In relation to the geographic location the only significant differences were lycopene content in salad tomatoes. The harvesting period influenced carotenoid composition, but a definite seasonal trend was not observed. During the summer the lycopene content was higher in summer-harvested tomatoes than in winter-harvested ones, for both cluster and cherry typologics. In relation to the harvesting season, no significant differences were found for the lycopene content in salad tomatoes, while the beta-carotene content was significantly different. Ripening stage influenced lycopene and carotene levels in all the varieties considered; significant differences in the phytoene values were found in cherry tomatoes. The highest carotenoid levels were recorded in fully ripe cherry tomatoes
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