Theoretical study of a new group of corrosion inhibitors

In the present work, the molecular interactions of four amino acid compounds were simulated through the density functional theory (DFT) indexes to study their inhibitive properties. The prototype inhibitors previously synthesized 2-amino-N-decylacetamide (G), 2-amino-N-decylpropionamide (A), 2-amino-N-decyl-3-methylbutyramide (V), and 2-amino-N-decyl-3-(4-hydroxyphenyl)propionamide (T) were used to test the accuracy of this calculation. The generalized gradient approximation (GGA) was the ab initio approach used to optimize the ground state of the molecules. The simulation of molecular dynamics with force field (AMBER) was calculated to obtain the interaction energy between the metallic surface and the inhibitor molecules. A strong correlation of the global and local indexes with the inhibiting capacity was observed. The inhibitive properties of compounds on mild steel in an aqueous hydrochloric acid solution agreed well with those derived from the reactivity and selectivity indexes in gaseous phase.

Electroencephalographical-anatomical correlation of brain tumours in infancy and childhood

EEG correlated with anatomical aspects of 198 brain tumours in children gave the following results in hemispheric neoplasms: a rather precise location in 40% of the cases; lateralized in 42%; 14% showed only generalized anomalies and 4% were normal tracings. The findings depended on location and ICP condition, but not on neurological signs nor on histological nature. Basal-midline location (88 tumors) displayed 82.4% abnormal EEGs; 50% pointed to the more invaded hemisphere, mainly from the upper brain stem, ventricles and basal ganglia regions. Hypophyseal tumours gave 50% abnormalities with proved compression of the third ventricle, hypothalamus and cerebral peduncles. In posterior fossa tumours (60 cases), abnormalities are frequent (86.7%), but the localizing value of EEG is uncertain due to bisynchronous bursts mainly in the occipital region; 15% were lateralized with correlating asymmetrical location and/or growth of tumours. Differences compared to adult tumours are mentioned as specially influenced by maturational processes of the brain.