51 resultados para Experimental literature


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This works describes the use of experimental design and surface response methodology for optimization of saponin extraction from Ampelozizyphus amazonicus. For this purpose, a method employing extraction based on maceration assisted by ultrasound technique was utilized. The following factors were studied: extraction length of time and solvent composition. The total saponin was determined by using a gravimetric method and the results expressed by their relative proportion to total crude extract. For the specific condition, 60% hydro-alcoholic solution and 18 minutes extraction length of time has shown the best results. This method can be useful for extraction of substances with biological importance

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The purpose of this paper is to present a classification criterion for general chemistry experiments departing from a survey of 35 years of the experimental general chemistry discipline at the Chemistry Institute - UNICAMP. It is shown that by considering the most remarkable characteristics of an experiment and classifying it under Conceptual, Fundamental, Methodological or Quantitative criterion, teachers could better develop the discipline plan and prevent a subject superposition. Taking into account the system Fe3+/SCN- , the article also exemplify how is possible to modify an experimental approach and to conceive other procedures with different didactic purposes.

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A practical and didactic sequence of experiments was proposed to illustrate the stereochemistry concept, optically active compounds, resolution of racemates, and use of the NMR technique, including 2D-COSY for identification of organic compounds, on a laboratory course for undergraduate students. The sequence was: extractions of racemic ibuprofen and chiral naproxen from commercial tablets; syntheses of diastereoisomeric amides reacting chiral (S)-(-)-α-methylbenzylamine with (±)-ibuprofen; separation and determination of absolute configuration of amides by ¹H NMR spectroscopy and GC analysis, and hydrolysis of amides to obtain (+)- and (-)-ibuprofen.

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Development of processing technology and equipments requires new methods and better quality of the processed product. In the continuous drying process, utilization of equipments that promotes an increment in the transfer coefficients becomes of the major interest. The use of vibrational energy has been recommended to the dispersed materials. Such method is based on the use of vibrational energy applied to disperse media. Thus, a literature review on the mass transfer and drying in vibro-fluidized beds was carried out, showing experimental results and mathematical modeling.

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Application of mechanical vibration to aid fluidization and to improve heat, mass and momentum transfer are usual processes in agricultural industry and it has found nowadays extensive applications in particle processing of materials difficult-to-fluidized. Equations and experimental data found in literature for the aerodynamics characteristics of vibro-fluidized beds are presented and discussed, emphasizing the vibration effect in the bed.

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In order to determine the energy needed to artificially dry an agricultural product the latent heat of vaporization of moisture in the product, H, must be known. Generally, the expressions for H reported in the literature are of the form H = h(T)f(M), where h(T) is the latent heat of vaporization of free water, and f(M) is a function of the equilibrium moisture content, M, which is a simplification. In this article, a more general expression for the latent heat of vaporization, namely H = g(M,T), is used to determine H for cowpea, always-green variety. For this purpose, a computer program was developed which automatically fits about 500 functions, with one or two independent variables, imbedded in its library to experimental data. The program uses nonlinear regression, and classifies the best functions according to the least reduced chi-squared. A set of executed statistical tests shows that the generalized expression for H used in this work produces better results of H for cowpea than other equations found in literature.

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The spouted and fluidized bed technologies are usually employed in operations of drying, coating and granulation of particles by the chemical and pharmaceutical industries. The use of these techniques in agronomy is limited to the treatment of some species of seeds. In this work, the objective was to analyse the fluid-dynamics of fluidized and spouted beds when broccoli (Brassica oleracea L. var. Italica) seeds are used and also to verify the influence on seed germination after 60 min of seed exposition to spouting or fluidization, at room temperature. The fluid-dynamics was defined by the measurements of the bed pressure drop as a function of the air flow rate for different seeds loads. The experimental conditions were based on the physical properties of the seeds and were limited by the apparatus dimensions. The cone-cylindrical bed was constructed in plexyglass to permit flow visualization. The values of the parameters: maximum pressure drop, minimum spouting flow rate and pressure drop, and stable spout pressure drop were experimentally obtained from the fluid-dynamic analysis and were compared with the values calculated by empirical equations found in the literature. The same procedure was carried out with the fluidized bed and the important parameters for this regime were the air velocity and the bed pressure drop at minimum fluidization. The analysis of seed germination indicated that no damage was caused to the seeds by the spout or fluidization processes.

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The present work evaluated the effect of low doses of X-irradiation on the repairing process of sutured and nonsutured skin wounds in rats. For that, rats underwent a surgical proceedure, in which a 20 x 5-millimeter rectangular wound approximately 2-millimeter-deep was made in the dorsal region of each animal, and were divided in four groups: nonirradiated nonsutured; irradiated nonsutured ; nonirradiated sutured and irradiated sutured. The animals under irradiation were protected, during exposure, with a 2-millimeter-thick lead apron in such a way that only the incision was irradiated. Each animal was submitted to 18 seconds of exposure, undergoing a total of 7.4 rads. The evaluation of the effects of X-rays on the repairing process was carried out through microscopic observation by means of hematoxylin-eosin staining for morphological evaluation, and silver impregnation under polarized light for the observation of collagen synthesis. The results have shown that X-irradiation has caused delay in the repairing process, but it did not stop its development. The irradiated nonsutured group was considered to show the greater delay when compared with the other groups.

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Objective: To review the literature about the use of atypical antipsychotics in the treatment of pathological aggression in children and adolescents. Method: The databases MEDLINE, SciELO, and LILACS were searched for publications in Portuguese or English from 1992 to August 2011 using the following keywords: mental disease, child, adolescent, treatment, atypical antipsychotic, aggressive behavior, aggression, and violent behavior. Results: Sixty-seven studies of good methodological quality and clinical interest and relevance were identified. Studies including children and adolescents were relatively limited, because few atypical antipsychotics have been approved by the Food and Drug Administration (FDA). All the medications included in this review (risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole and clozapine) have some effectiveness in treating aggression in children and adolescents, and choices should be based on clinical indications and side effects. Conclusions: There are few studies about the effectiveness and safety of atypical antipsychotics for the pediatric population, and further randomized controlled studies with larger groups of patients and more diagnostic categories, such as severe conduct disorder and oppositional defiant disorder, should be conducted to confirm the results reported up to date and to evaluate the impact of long-term use.

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INTRODUCTION: Subclinical hypothyroidism (SCH), defined as elevated concentrations of thyroid stimulating hormone (TSH) despite normal levels of thyroid hormones, is highly prevalent in Brazil, especially among women and the elderly. Although an increasing number of studies have related SCH to an increased risk of coronary artery disease and mortality, there have been no randomized clinical trials verifying the benefit of levothyroxine treatment in reducing these risks, and the treatment remains controversial. OBJECTIVE: This consensus, sponsored by the Thyroid Department of the Brazilian Society of Endocrinology and Metabolism and developed by Brazilian experts with extensive clinical experience with thyroid diseases, presents these recommendations based on evidence for the clinical management of SCH patients in Brazil. MATERIALS AND METHODS: After structuring the clinical questions, the search for evidence in the literature was initially performed in the MedLine-PubMed database and later in the Embase and SciELO - Lilacs databases. The strength of evidence was evaluated according to the Oxford classification system and established based on the experimental design used, considering the best available evidence for each question and the Brazilian experience. RESULTS: The topics covered included SCH definition and diagnosis, natural history, clinical significance, treatment and pregnancy, and the consensus issued 29 recommendations for the clinical management of adult patients with SCH. CONCLUSION: Treatment with levothyroxine was recommended for all patients with persistent SCH with serum TSH values > 10 mU/L and for certain patient subgroups.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física