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Corrosion inhibition of copper through six bipyrazolic compounds has been elucidated by means of density functional theory (DFT)-derived reactivity indexes. The DFT calculated parameters and experimental corrosion inhibition efficiency (IE%) indicate that their inhibition effect is closely related to the frontier orbital energies, polarizability, electronic chemical potential and global nucleophilicity. The quantum chemistry calculations were performed at the B3LYP/6-31G (d) level. The theoretical results, predicted using DFT-based reactivity indexes, are in good agreement with experimental outcomes. [ABSTRACT FROM AUTHOR]

This paper summarizes the results of a study that comprised a survey along with a morphological characterization of Artemia populations from seven sebkhas, one chott, and an inland salt lake in Algeria. Sebkhas and chotts are two different types of closed inland basins. Morphological characters together with a multivariate discriminant analysis applied to morphometric data obtained from adult specimens cultured under standard conditions, were used to differentiate the species and strains. The bisexual species A. salina (L., 1758) is present in seven of these saltmarshes, but frequently cooccurs with diploid and tetraploid parthenogenetic strains. The biodiversity pattern of the populations of Artemia in Algeria appears to be similar to that found in the rest of the western Mediterranean region. [ABSTRACT FROM AUTHOR]

Abstract: The l,l-Phe-Leu-Cu(II), l,l-Leu-Phe-Cu(II), l,l-Phe-Met-Cu(II), and l,l-Met-Phe-Cu(II) systems were studied using molecular modelling. The results obtained, which are in good agreement with results obtained by potentiometric studies show a significant increase in stability of copper complexes, when an aromatic residue is located in C-terminal (compared to the l,l-dipeptides containing the same amino acid residues), this phenomenon is attributed to the interaction between the d-orbital of copper and the π-electrons of the aromatic ring. [Copyright &y& Elsevier]

Carbohydrates play vital roles in many biological processes, such as recognition, adhesion, and signalling between cells. The Lewis X determinant is a trisaccharide fragment implicated as a specific differentiation antigen, tumor antigen, and key component of the ligand for the endothelial leukocyte adhesion molecule, so it is necessary or essential to determine and to know their conformational and structural properties. In this work, conformational analysis was performed using molecular dynamics (MD) simulation with the AMBER10 program package in order to study the dynamic behavior of of the Lewis X trisaccharide (β-D-Gal- (1,4)-[α-L-Fuc-(1,3)]-β-D-GlcNAc-OMe) and the Lewis X pentasaccharide (β-D-Gal-(1,4)-[α-L-Fuc-(1,3)]-β-D-GlcNAc-(1,3)- β-D-Gal-(1,4)-β-D-Glu-OMe) in explicit water model at 300 K for 10 ns using the GLYCAM 06 force field. [ABSTRACT FROM AUTHOR]

Methyl 2-(bis((3,5-dimethyl-1 H-pyrazol-1-yl)methyl)amino) acetate, BT36, and methyl 2-(bis((3,5-dimethyl-1 H-pyrazol-1-yl)methyl)amino)-3-(1 H-indol-3-yl)propanoate, BT 43, have been synthesized. Investigation by weight-loss measurement and use of electrochemical techniques revealed the compounds are very effective inhibitors of corrosion of C38 steel in 1 M HCl solutions-percentage protection exceeded 95 % for BT43 at concentrations as low as 10 M. An impedance study in the absence and presence of these compounds revealed the mechanism of protection was cathodic inhibition by polarization and charge-transfer. The Langmuir adsorption isotherm was obeyed. Quantum chemical data calculated by use of DFT at the B3LYP/6-31G* level of theory revealed a good correlation between inhibition efficiency and the molecular structure of BT36 and BT43. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, the separation energy (Δ E), and the dipole moment ( μ) from the inhibitor to the metal surface explain the experimental data well. [ABSTRACT FROM AUTHOR]

Abstract: N-Phenyl oxalic dihydrazide (PODH) and oxalic N-phenylhydrazide N′-phenylthiosemicarbazide (OPHPT), synthesized in our laboratory, were tested as inhibitors for the corrosion of mild steel in molar HCl by electrochemical measurements. Inhibition efficiencies up to 92% for OPHPT and 79% for PODH can be obtained. Polarization curves reveal that PODH and OPHPT act as mixed type inhibitors. Adsorption of these inhibitors on the mild steel surface was found to obey the Langmuir adsorption isotherm. Results show that the rate of corrosion of mild steel increased with increasing temperature over the range 25–55°C both in the presence of inhibitors and in their absence. Activation energies in the presence and absence of PODH and OPHPT were obtained by measuring the temperature dependence of the corrosion current. The reactivity of these compounds was analyzed through theoretical calculations based on density functional theory to explain the different efficiency of these compounds as corrosion inhibitors. [Copyright &y& Elsevier]