RESUMEN
In this study, a new marine oil that contains 45% docosahexaenoic acid (DHA, 22:6n-3) and 13% docosapentaenoic acid (DPA, 22:5n-6) was administered to rats. The metabolism and distribution of DPA in rats was investigated. In experiment 1, the effects of DHA and n-6 fatty acids (linoleic acid, LA; arachidonic acid, AA; and DPA) on AA contents were investigated in vivo. LA group: LA 25%, DHA 30%; LA-DPA group: LA 15%, DPA 10%, DHA 35%; LA-AA-DPA group: LA 10%, AA 5%, DPA 10%, DHA 35% were administered to rats for 4 wk. In the liver, the AA content in the LA-DPA and LA-AA-DPA groups was significantly higher than in the LA group. The decreased AA contents in the LA group might be caused by DHA administration. Although DHA also was administered in the LA-DPA and LA-AA-DPA groups, the AA contents in these two groups did not decrease. These results suggested that DPA retroconverted to AA, blunting the decrease in AA content caused by DHA administration. To conduct a detailed investigation on DPA metabolism and its relation with AA and DHA, rat hepatocytes were cultured with purified DPA and DHA for 24 h. We discovered the retroconversion of DPA to AA occurred only when AA content was decreased by a high DHA administration; it did not occur when AA content was maintained at a normal level.
Asunto(s)
Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/metabolismo , Hígado/química , Hígado/metabolismo , Animales , Ácido Araquidónico/metabolismo , Química Encefálica , Células Cultivadas , Grasas Insaturadas en la Dieta/administración & dosificación , Grasas Insaturadas en la Dieta/metabolismo , Ácidos Docosahexaenoicos/administración & dosificación , Ácidos Docosahexaenoicos/análisis , Ácidos Docosahexaenoicos/metabolismo , Ácidos Grasos/análisis , Ácidos Grasos Insaturados/administración & dosificación , Masculino , Especificidad de Órganos , Ratas , Ratas Wistar , Testículo/química , Testículo/metabolismoRESUMEN
This paper presents the tuning of the structure and parameters of a neural network using an improved genetic algorithm (GA). It is also shown that the improved GA performs better than the standard GA based on some benchmark test functions. A neural network with switches introduced to its links is proposed. By doing this, the proposed neural network can learn both the input-output relationships of an application and the network structure using the improved GA. The number of hidden nodes is chosen manually by increasing it from a small number until the learning performance in terms of fitness value is good enough. Application examples on sunspot forecasting and associative memory are given to show the merits of the improved GA and the proposed neural network.
RESUMEN
This paper presents stability analysis of fuzzy model-based nonlinear control systems, and the design of nonlinear gains and feedback gains of the nonlinear controller using a genetic algorithm (GA) with arithmetic crossover and nonuniform mutation. A stability condition is derived based on Lyapunov's stability theory with a smaller number of Lyapunov conditions. A solution of the stability conditions is also determined using GA. An application example of stabilizing a cart-pole typed inverted pendulum system is given to show the stabilizability of the nonlinear controller.
RESUMEN
A peptide isolated from rats habituated to a sound stimulus has been given the structure (see article) Glu-Ala-Gly-Tyr-Ser-Lys-OH. A synthesis of this compound afforded a product that different from the natural material on the basis of chromatographic and physiological comparisons. The proposed sequence must therefore be in error.