Biomedical subjects

C R Souza

Publications and source records attributed to C R Souza.

3 recordsLinked to original sources

PubMed2003

O/w dispersions development containing liquid crystals.

Liquid crystals are defined as the intermediary state between solid and liquid and also called of mesomorphous phase or crystalline phase, presenting characteristics of the mentioned physical states. For the simple emulsions that intermediary phase can act as forms of encapsulation of drugs providing its controlled liberation and besides, it can increase cutaneous hydration. These characteristics evidences the differentiation of the developed formulations and the use of the same ones in the release of new cosmetic vehicles. In that research we use vegetable oils (coffee, tomato), mineral oil, surfactants like phosphorics esthers (fractions A and B) and distilled water as aqueous phase. The stable formulations were submitted to stability physic-chemical preliminary tests (pH values determination, electric conductivity values, centrifugation and thermal stress) and later the compositions were submitted to accelerated stability tests (cold-hot cycle in the following temperature conditions--4 +/- 2 degrees C, 25 +/- 2 degrees C and 45 +/- 2 degrees C). Crystalline phase was identified by microscopy polarization. The recently prepared formulations and aged formulations (after 30 days) were appraised for rheology.

Cosmetics↗

PubMed2001

Three case studies of the GasNet model in discrete domains.

A new neural network model - the GasNet - has been recently reported in the literature, which, in addition to the traditional electric type, point-to-point communication between units, also uses communication through a diffilsable chemical modulator. Here we assess the applicability of this model in three different scenarios, the XOR problem, a food gathering task for a simulated robot, and a docking task for a virtual spaceship. All of them represent discrete domains, a contrast with the one where the GasNet was originally introduced, which had an essentially continuous nature. These scenarios are well-known benchmark problems from the literature and, since they exhibit varying degrees of complexity, they impose distinct performance demands on the GasNet. The experiments were primarily intended to better understand the model, by extending the original problem domain where GasNet was introduced. The results reported point at some difficulties with the current GasNet model.

Neural Networks, Computer↗

PubMed2000

Compounds extracted from Phyllantus and Jatropha elliptica inhibit the binding of [3H]glutamate and [3H]GMP-PNP in rat cerebral cortex membrane.

Glutamate is to be considered a nociceptive neurotransmitter and glutamatergic antagonists present antinoceptive activity. In this study we investigated the effects of the naturally occurring antinociceptive compounds rutin, geraniin and quercetine extracted from Phyllanthus, as well as the diterpene jatrophone, extracted from Jatropha elliptica on the binding of [3H]glutamate and [3H]GMP-PNP [a GTP analogue which binds to extracellular site(s), modulating the glutamatergic transmission] in rat brain membrane. Jatrophone inhibited [3H]glutamate binding and geraniin inhibited [3H]GMP-PNP binding. Quercetine inhibited the binding of both ligands. These results may indicate a neurochemical parameter possibly related to the antinoceptive activity of these natural compounds.

Animals↗