Biomedical subjects

J López-Fidalgo

Publications and source records attributed to J López-Fidalgo.

3 recordsLinked to original sources

PubMed2007

Optimal designs for radiation retention with poisson correlated response.

In this paper we describe a non-linear model with correlated observations which accounts for the elimination rate of radiation in the lung of individuals who have been exposed to an accidental intake at some time. The response is then modelled as a conditional Poisson distribution. When the leak is moderate or the size of the particles is large a theoretical justification of this assumption is given and D-optimal designs are computed.

Dose-Response Relationship, Radiation↗

PubMed2006

Algorithm to find gene expression profiles of deregulation and identify families of disease-altered genes.

MOTIVATION: Alteration of gene expression often results in up- or down-regulated genes and the most common analysis strategies look for such differentially expressed genes. However, molecular disease mechanisms typically constitute abnormalities in the regulation of genes producing strong alterations in the expression levels. The search for such deregulation states in the genomic expression profiles will help to identify disease-altered genes better. RESULTS: We have developed an algorithm that searches for the genes which present a significant alteration in the variability of their expression profiles, by comparing an altered state with a control state. The algorithm provides groups of genes and assigns a statistical measure of significance to each group of genes selected. The method also includes a prefilter tool to select genes with a threshold of differential expression that can be set by the user ad casum. The method is evaluated using an experimental set of microarrays of human control and cancer samples from patients with acute promyelocytic leukemia.

Algorithms↗

PubMed2002

Design issues for the Michaelis-Menten model.

We discuss design issues for the Michaelis-Menten model and use geometrical arguments to find optimal designs for estimating a subset of the model parameters, or a linear combination of the parameters. We propose multiple-objective optimal designs when the parameters have different levels of interest to the researcher. In addition, we compare six commonly used sequence designs in the biological sciences for estimating parameters and, propose optimal choices for the parameters for geometric designs using closed-form efficiency formulas.

Algorithms↗