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Estadística para investigadores : introducción al diseño de experimentos, análisis de datos y construcción de modelos

Source: OAI

ABSTRACT Sumario: Comparación de dos tratamientos -- Comparación de más de dos tratamientos -- Midiendo los efectos de variables -- Construcción y empleo de modelos

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    ABSTRACT: A study of ultrasonically assisted extraction of bioactive principles from Quillaja Saponaria Molina (Quillay) is presented. To address the problem it was studied the effects that could influence the extraction process through a two-level Factorial Design. The effects considered in the Experimental Design were: Granulometry, Extraction time, Acoustic Power and Acoustic Impedance.The production of the quillaja extracts is done with an aqueous extraction and the process is assisted by an ultrasonic field; no other solvents are used in its production. The final product only incorporates natural ingredients and raw materials, authorized for their use in food manufacturing processes.The principal factors affecting the ultrasonic extraction process were: Granulometry and Extraction time. The enhanced of ultrasonic assisted extraction ratio was measuring the increasing yield of extracted components, the extraction ratio was increased by ultrasonic effect and a reduction in extraction time was verified. In addition the process can be carried out at temperatures lower than the traditional way.The influence of ultrasound on the quality of bioactive principles was examined by HPLC technique and no influence of ultrasound on natural components was found.
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    ABSTRACT: Introduction: Magnolia grandiflora was firstly typified by Linneo as Magnolia grandiflora (L.) in 1759. It is an ever-green tree introduced by the Spanish during the conquer and is now widely distributed in America. Ethnomedically, it has been previously reported that M. grandiflora extracts have been used since ancient times to treat cardiac pathologies, a practice that remains to this day. Materials and methods: Vulgarenol, a sesquiterpene isolated and purified from Magnolia grandiflora flowers petals extracts by high-performance liquid chromatography (HPLC), was pharmacologically evaluated on isolated and perfused guinea pigs hearts according to Langendorff. In another experimental group, hypertension was induced by chronic blockade of nitric oxide synthesis by administrating N w - nitro-L-arginine methyl ester (70 mg/kg, i.p.). Under these conditions, coronary vascular resistance, nitric oxide production and cyclic guanosine monophosphate release were evaluated. Results: Vulgarenol decreases coronary vascular resistance in isolated and perfused guinea pigs hearts according to Langendorff. Our results suggest that vulgarenol pharmacological action ongoes with statistically significant increases in nitric oxide and cyclic guanosine monophosphate production, which were inhibited by the blocking effect of antagonists and inhibitors such as gadolinium (III) chloride, N w - nitro-L-arginine methyl ester and 1H-(1,2,4) oxadiazolo (4,2-a) quinoxalin-1-one. In the hypertensive animals, it was observed that vulgarenol partially reverts hypertension induced by chronic blockade of nitric oxide synthesis. Additionally, drugs such as pentoxyphylline and milrinone potentiate the pharmacological effect induced by vulgarenol. Such effects suppose a calcium-dependent process, along with the possible participation of the constitutive and inducible nitric oxide synthases, increasing cyclic guanosine monophosphate production by means of phosphodiesterase III inhibition. Conclusion: Our results support the fact that vulgarenol-induced vasorelaxation is mediated through the nitric oxide/soluble guanylyl cyclase pathway.