Biomedical subjects

A N de Souza

Publications and source records attributed to A N de Souza.

3 recordsLinked to original sources

PubMed2001

A novel approach for solving constrained nonlinear optimization problems using neurofuzzy systems.

A neural network model for solving constrained nonlinear optimization problems with bounded variables is presented in this paper. More specifically, a modified Hopfield network is developed and its internal parameters are computed using the valid-subspace technique. These parameters guarantee the convergence of the network to the equilibrium points. The network is shown to be completely stable and globally convergent to the solutions of constrained nonlinear optimization problems. A fuzzy logic controller is incorporated in the network to minimize convergence time. Simulation results are presented to validate the proposed approach.

Fuzzy Logic↗

PubMed1996

[Health education--knowledge and sources of information about acquired immunodeficiency or AIDS].

Questionnaires were answered by 151 students, 10 to 19 years old, from an elementary, Jr. and Senior-high State School in Florianópolis, State of Santa Catarina-Brazil. The objectives were: to identify information sources; transmission mechanisms; prevention forms and the interest shown by students in acquiring new knowledge on HIV/AIDS. Based on the responses, authors found out that 90.06% of the students had heard about AIDS on TV, 29.13% had been informed about the theme through a teacher. It was also observed that 45.03% would seek for orientation from their parents, and 9.93% from their teachers.

Acquired Immunodeficiency Syndrome↗

PubMed1991

An enkephalin degrading aminopeptidase of human brain preserved during the vertebrate phylogeny.

1. A soluble human brain aminopeptidase which hydrolyses the Tyr-Gly bond of Met-enkephalin and Leu-enkephalin was identified in the brains of the following vertebrates: mammals (Callithrix jacchus and Rattus norvegicus), bird (Gallus domesticus), reptile (Tupinambis teguixin), amphibia (Bufo paracnemis), fish (Sarotherdon niloticus) and elasmobranchy (Galeocerdo cuvieri). 2. The properties of this enzyme are: molecular weight near 100,000 Da, isoelectric point near 4.9, optimum pH near 7.5, activation by dithiothreitol, strong inhibition by Cu2+, Zn2+, Ni2+, puromycin and bacitracin, hydrolysis of enkephalins and basic and neutral aminoacid-beta-naphythylamide substrates. 3. The results indicate the preservation of this human brain aminopeptidase during the course of vertebrate phylogeny.

Amino Acid Sequence↗