Growth kinetics and mechanism of the initial oxidation of Al-based Al-Mg alloys

The relationship between the growth kinetics and the local chemical states of Al, Mg and O ions in ultrathin (<3 nm) oxide films grown on Al-based Al-Mg substrates at T = 300-610 K was established by ellipsometry and XPS. At T ? 385 K, an Al-oxide film of near-limiting thickness (∼1 nm) is formed, which exhibits interfacial and bulk-like states for the Al cations. At T > 385 K, continued growth is realized by the preferential oxidation of interfacially segregated Mg, resulting in the sequential appearance of interfacial and bulk-like states for the Mg cations.     

Wild edible fruit diversity and its significance in the livelihood of indigenous tribals: Evidence from eastern India

A number of wild plants, used by rural and tribal populations and contributing significantly to their livelihood and food security have escaped recognition and scientific inquiry. Their distribution, conservation, mode of harvest by locals and optimal use require region-specific assessment in order to integrate them into developmental interventions. This study analyzed the collection, consumption, sale and income from edible forest fruits in 49 tribal villages spread over five districts of Orissa State in eastern India. Density, dominance and diversity of species yielding wild fruit were measured by studying ecological parameters in the sample plots. We estimated an average of 48 fruit plants per hectare of deciduous forests. Fifty-six wild edible fruit species belonging to 40 genera in 26 families were recorded in the study region, many of which have multiple uses. Indigenous fruits formed part of the family diet with average annual consumption of 73 kg per household. Sale of wild fruits contributed 15 % of income for tribal households. Despite their good knowledge of indigenous fruits, the tribal populations have not adopted fruit tree farming which would enhance their nutrition and income.     

Effects of protein-surface interactions on protein ion signals in MALDI mass spectrometry

The influence of polymer surface-protein binding affinity on protein ion signals in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is examined. The surfaces of poly(vinylidene fluoride) and poly(ethylene terephthalate) polymer substrates are modified by pulsed rf plasma deposition of allylamine. By varying the on/off duty cycle of the pulsed rf plasma, the polymer substrate surfaces are coated with thin films having varying densities of surface amine groups. The varying surface amine density is shown to lead to systematic changes in the surface binding affinity for the 125I-radiolabeled peptides angiotensin I and porcine insulin. Unlabeled angiotensin I and porcine insulin are then deposited on the pulsed rf plasma-modified substrates and analyzed by MALDI mass spectrometry. The experimental approach involves applying the peptide to the modified polymer surface in an aqueous phosphate-buffered saline solution and allowing the peptide solution to dry completely under ambient conditions. Subsequently, the MALDI matrix alpha-cyano-4-hydroxycinnamic acid in methanol and 10% trifluoroacetic acid in water are added to the peptide-coated modified polymer surfaces. The results of these studies demonstrate that, for the sample preparation method employed, increases in the surface peptide binding affinity lead to decreases in the peptide MALDI ion signal.     

Biological activity of carboxy-terminal gastrin analogs

Amidated forms of gastrin are derived by post-translational processing of a large precursor peptide and stimulate gastric acid secretion via the gastrin/CCK(B) receptor. Non-amidated biosynthetic intermediates may exert biological effects through other mechanisms, but their effect on gastric acid secretion is unclear. Amidated gastrins stimulate acid secretion mainly by releasing histamine from mucosal enterochromaffin-like cells. This study examines the effects on histamine release from the vascularly perfused rat stomach of amidated gastrin-17, COOH-terminal glycine-extended gastrin-17, gastrin-17 extended at the COOH-terminal including the remaining progastrin sequence, and carboxy-terminal progastrin fragments (SAEDEN and GRRSAEDEN). Carboxy-terminal extended gastrins induced histamine release which was inhibited by the gastrin/CCK(B) antagonist L-740,093, but had to be given in concentrations 100-fold higher than amidated gastrin-17 to produce comparable effects. These progastrin-derived peptides are found in high concentrations in some patients with the Zollinger-Ellison syndrome and may contribute to acid hypersecretion and other gastrin/CCK(B) receptor mediated responses.     

Effects of chemical reaction on free convection flow through a porous medium bounded by a vertical surface

The effect of a chemical reaction on a free convection flow through a porous medium bounded by a vertical infinite surface has been studied. Velocity, temperature, and concentration profiles have been obtained for different values of parameters like the Grashof number, Prandtl number, and the chemical reaction parameter in the presence of homogeneous chemical reaction of first order. It is observed that the velocity and concentration increase during a generative reaction and decrease in a destructive reaction. The same is true for the behavior of the fluid temperature. The presence of the porous media diminishes the temperature.     

Multi-objective evolutionary algorithm for SSSC-based controller design

In this paper, an evolutionary multi-objective optimization approach is employed to design a static synchronous series compensator (SSSC)-based controller. The design objective is to improve the transient performance of a power system subjected to a severe disturbance by damping the multi-modal oscillations namely; local mode, inter-area mode and inter-plant mode. A genetic algorithm (GA)-based solution technique is applied to generate a Pareto set of global optimal solutions to the given multi-objective optimization problem. Further, a fuzzy-based membership value assignment method is employed to choose the best compromise solution from the obtained Pareto solution set. Simulation results are presented and compared with a PI controller under various disturbances namely; three-phase fault, line outage, loss of load and unbalanced faults to show the effectiveness and robustness of the proposed approach.