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A liquid chromatographic (LC) method was developed to assess the potency of products that contain dehydroepiandrosterone (DHEA), a precursor hormone synthesized from cholesterol by the human adrenal cortex and converted to potent androgens and/or estrogens in peripheral tissues. Forty-five commercial products (both single and multi-ingredient) were subjected to analysis by the proposed method. A Zorbax Rx C18 column with a mobile phase containing acetonitrile–0.025M phosphate buffer (60 + 40), pH 3.50, and UV detection at 292 nm was used for 87% of the products. An alternative mobile phase containing methanol–0.025M phosphate (75 + 25), pH 3.50, was used to isolate DHEA from more complex product mixtures. Assay values varied from 0 to 109.5% of the declared amount with an overall mean value of 91.1%. The recoveries based on fortified products ranged from 96.4 to 101.2%, and the intraday precision (RSD, n = 5) varied from 0.50 to 1.66%.

Herbal preparations derived from the dried seeds of guarana (Paullinia cupana) have become a popular nutritional supplement used for stimulatory purposes. Once considered a drug substance in the United States, guaraná currently is classified as a food additive and dietary supplement. The pharmacological activity of guaraná-containing products is primarily due to methylxanthine alkaloids. For guaraná preparations, methylxanthine levels and, more significantly, the presence of several polyphenol compounds (i.e., catechins) provide phytochemical markers of authenticity. Methylxanthines and polyphenols are extracted from sample matrix with a heated phosphate buffer-methanol solution, the cooled extract is filtered, and the extract is injected into the liquid chromatographic (LC) system. A Nova-Pak C18 column eluted with phosphate buffer-methanol mobile phase (pH = 3.50) and monitored at 272 nm gave satisfactory resolution for the methylxanthines theobromine, theophylline, caffeine and the polyphenols (+)-catechin and (−)-epicatechin. Twenty-four products including dried seeds, dried paste, seed powders, tablets, and capsule formulations were assayed and conclusions were drawn about their authenticity. The LC system responded linearly to methylxanthines over the 100-fold range in concentration from 0.043 to 4.30 μg/mL for theobromine and caffeine and from 0.041 to 4.10 μg/mL for theophylline. Precision data for the 3 methylxanthines obtained from 10 different products (n = 5) gave relative standard deviation (RSD) values of 1.18-15.52% within a concentration range of 0.01-52.28 mg/g. Recoveries of methylxanthines from fortified products varied from 87.5 to 120.0%. The response for catechins was linear over a 200-fold range in concentration of 0.05-10.0 μg/mL. Precision data from 5 products (n = 5) gave RSD values of 1.08-5.54% within a concentration range of 0.34-32.65 mg/g. Recoveries from these products ranged from 87.7 to 109.7%. Results and chromatographic profiles for 14 commercial products in solid dosage form indicate that a number of these products may not contain authentic guaraná as an active ingredient or contain less than the declared quantity of guaraná. The proposed procedure also was applied to 2 carbonated soft drinks and a sample of mate.

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-PostdramaticRESUMO -Teatro Pós-dramático e Performance Pós-dramática -Este ensaio inicia com o conceito de teatro pós-dramático conforme formulado pelo teórico alemão HansThies Lehmann e nele se consideram as obras recentes de vários diretores internacionais relevantes -Ivo van Hove, Punchdrunk, Signa, entre outros -como exemplos de performance pós-dramática. Argumenta-se que o ponto comum a essas obras desafia o conceito tradicional de mimese e do universo teatral como construto fictício claramente isolado da vida cotidiana e de suas circunstâncias. Palavras-chave: Teatro. Performance. Pós-dramático. Hans-Thies Lehmann. Artes.

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Southeastern Nebraska is underlain by EarlyProterozoic rocks of the Central Plains (1,600 to 1,800 Ma) and Penokean (1,830 to 1,890 Ma) Provinces. The Midcontinent Rift System was imposed upon and reflects the preexisting tectonic grain of the older basement. During Paleozoic time several periods of structural change occurred related to the Midcontinent Rift System. In the same geographic area, there was successive development of the Southeast Nebraska arch, the North Kansas basin, the Nemaha uplift, and the Table Rock arch. The locations of these regional features were controlled by the patterns established by rift tectonics. Features such as the Eastern Nebraska high, the Abilene Anticline, the Union fault, and the Burchard fault are reactivations of specific rift features.