ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Blackwell Publishing  (1)
  • Centro Nacional de Investigaciones Científicas  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing
    Expert systems 21 (2004), S. 0 
    ISSN: 1468-0394
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Computer Science
    Notes: Abstract: A key problem of modular neural networks is finding the optimal aggregation of the different subtasks (or modules) of the problem at hand. Functional networks provide a partial solution to this problem, since the inter-module topology is obtained from domain knowledge (functional relationships and symmetries). However, the learning process may be too restrictive in some situations, since the resulting modules (functional units) are assumed to be linear combinations of selected families of functions. In this paper, we present a non-parametric learning approach for functional networks using feedforward neural networks for approximating the functional modules of the resulting architecture; we also introduce a genetic algorithm for finding the optimal intra-module topology (the appropriate balance of neurons for the different modules according to the complexity of their respective tasks). Some benchmark examples from nonlinear time-series prediction are used to illustrate the performance of the algorithm for finding optimal modular network architectures for specific problems.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2021-05-19
    Description: El D-004 es un extracto lipídico obtenido del fruto de la palma real (Roystonea regia) (Arecaceae) que consiste en una mezcla reproducible de ácidos grasos, en la cual el ácido oleico, el laurico y el palmítico son los más abundantes. El tratamiento oral con D-004 inhibe significativamente la hiperplasia prostática (HP) inducida por testosterona en roedores. El objetivo de este trabajo fue investigar si el D-004 induce mutaciones génicas puntuales en el ensayo de Ames por incorporación directa en placa. Se utilizaron las cepas TA 1535, TA 98 y TA 100 de Salmonella typhimurium. El ensayo se realizó tanto con la adición de la fracción microsomal hepática (S9) como sin ella. Como controles positivos en este ensayo se emplearon dos mutágenos, uno directo: la azida de sodio (AzNa) y uno indirecto: el 2-acetil amino fluoreno (2-AAF). Las concentraciones de D-004 empleadas fueron 5, 50, 500, 2000 y 5000 μg/placa, utilizando el vehículo Tween 65 (0,2 %) como control negativo. Los resultados mostraron que el D-004 no afectó significativamente la frecuencia de reversión respecto al control negativo para ambas variantes del ensayo de Ames, con o sin activación metabólica, en las cepas empleadas. Como era esperado, los controles positivos AzNa y 2-AAF incrementaron significativamente el número de colonias revertantes con respecto al control negativo. Los niveles de frecuencia de reversión espontánea y el número de revertantes obtenidas con los controles positivos en este estudio están en el rango de los valores históricos obtenidos en nuestro laboratorio para cada una de las cepas empleadas. El presente estudio demuestra que el D-004 no presenta potencial mutagénico en el ensayo de Ames por incorporación directa a placa en las cepas estudiadas.
    Description: D-004 is a lipid extract of the fruits of the Cuban royal palm (Roystonea regia) (Arecaceae), which consist in a mixture of fatty acids, in which oleic, lauric and palmitic are the most abundant. Oral treatment with D-004 significantly prevents the prostate hyperplasia (PH) induced with testosterone in rodents. This study was conducted to investigate whether D-004 induces gene mutations in the Ames test for plate incorporation method. The tester strains used were TA 1535, TA 98 y TA 100 of Salmonella typhimurium. The test was done with and without metabolic activation. As positive controls two mutagenic agents, sodium azide (NaAz) and 2-acetyl aminofluorene (2-AAF), were used. The doses of D-004 used were 5, 50, 500, 2000 y 5000 μg/plate, using Tween 65 (0.2 %) vehicle as negative control. D-004 did not change significantly the reversion frequency compare with negative control in the Ames test in both alternatives with or without S9 metabolic activation, in the used strains. As expected, the positive controls, NaAz and 2-AAF significantly increased the frequency of revertants compared with the negative control. The frequencies of spontaneous reversions and the number of revertants observed in this study are within the historical values obtained in our lab for each strain. This study demonstrates that D-004 has not potential mutagenic in the Ames test for plate incorporation.
    Description: Centro de Productos Naturales. Centro Nacional de Investigaciones Científicas
    Description: Published
    Description: Ames test, D-004, Roystonea regia, potential mutagenic
    Keywords: Fatty acids ; Fatty acids
    Repository Name: AquaDocs
    Type: Journal Contribution
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...