Inhibition of leukocyte 5-lipoxygenase by phenolics from virgin olive oil

Interest in the health-promoting effects of virgin olive oil, an important part of the 'Mediterranean diet', prompted us to determine the anti-eicosanoid and antioxidant effects in leukocytes of the principal phenolic compounds from the 'polar fraction': oleuropein, tyrosol, hydroxytyrosol, and caffeic acid. In intact rat peritoneal leukocytes stimulated with calcium ionophore, all four phenolics inhibited leukotriene B4 generation at the 5-lipoxygenase level with effectiveness hydroxytyrosol > oleuropein > caffeic acid > tyrosol (approximate EC50 values: 15, 80, 200, and 500 microM, respectively). In contrast, none of these compounds caused substantial inhibition of thromboxane generation via the cyclo-oxygenase pathway. Hydroxytyrosol, caffeic acid, oleuropein, and tyrosol (decreasing order of effectiveness) also quenched the chemiluminescence signal due to reactive oxygen species generated by phorbol myristate acetate-stimulated rat leukocytes. None of these compounds were toxic to leukocytes at the concentrations tested. We conclude that the phenolics found in virgin olive oil possess an array of potentially beneficial lipoxygenase-inhibitory, prostaglandin-sparing, and antioxidant properties.     

Suicide risk assessment in a college student population.

A group of 211 students at a midwestern university completed the Suicidal Behaviors Questionnaire (M. M. Linehan & S. L. Nielsen, 1981), Adult Suicidal Ideation Questionnaire (W. M. Reynolds, 1991a), Multi-Attitude Suicide Tendency Scale (I. Orbach et al., 1991), Beck Helplessness Scale (A. T. Beck, A. Weissman, D. Lester, & L. Trexler, 1974), and the Reasons for Living Inventory (M. M. Linehan, L. J. Goodstein, S. L. Nielsen, & J. A. Chiles, 1983) to determine if this group of commonly used self-report measures can distinguish between individuals with high and low levels of suicidal ideation and history of self-harmful behaviors. Exploratory principal-axis factor analysis resulted in an interpretable 2-factor solution accounting for 36.2% of the variance in suicidality. Support for convergent validity of the chosen measures was also found. It appears that rapid, accurate assessment of university student suicide risk is possible. Implications for reduction of suicide risk in this segment of the population are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Corrosion of MCrAlY: Pt composites prepared by spark plasma sintering

Cyclic oxidation tests of sintered MCrAlY:Pt composites were carried out at temperatures of 1223 and 1273?K. Composite tablets were previously produced by spark plasma sintering. To assess an effect of platinum dispersed, microstructural characterisation was performed on the tablets before and after the cyclic oxidation treatment. Scanning electron microscopy analysis of the oxide layer showed that the presence of typical α-Al₂O₃ and NiAl₂O₄ spinel had structure columnar and equiaxial in both samples. Fine sintered microstructure and addition of Pt into the MCrAlY matrix enhanced the resistance of the material to cyclic oxidation.     

Implementation of periodic boundary conditions for loading of mechanical metamaterials and other complex geometric microstructures using finite element analysis

The implementation of periodic boundary conditions (PBCs) is one of the most important and difficult steps in the computational analysis of structures and materials. This is especially true in cases such as mechanical metamaterials which typically possess intricate geometries and designs which makes finding and implementing the correct PBCs a difficult challenge. In this work, we analyze one of the most common PBCs implementation technique, as well as implement and validate an alternative generic method which is suitable to simulate any possible 2D microstructural geometry with a quadrilateral unit cell regardless of symmetry and mode of deformation. A detailed schematic of how both these methods can be employed to study 3D systems is also presented.

     

Prompt fission-neutron spectra in the reactions of 1.5-MeV neutrons with235U

Translated from Atomnaya énergiya, Vol. 69, No. 1, pp. 28–31, July, 1990.     

Preferential adsorption in polymer/solvent-1 /solvent-2 solutions by infrared spectroscopy

IR spectroscopy is shown to be a suitable technique for preferential adsorption studies in the following solvent-1/solvent-2/polymer systems: poly(N-vinylcarbazole) and polyacenaphthene in nitrobenzene/dioxane, nitrobenzene/ tetrahydrofuran, and nitrobenzene/cyclohexanone. Values of the preferential adsorption parameters derived from the Schultz-Flory theory agree with those from IR when both solvents in the ternary system are considered to be good solvents for the polymer. In the systems studied, the relative adsorptions of solvent-1 and solvent-2 by the polymer depend on the solvent mixture composition. The number of adsorbed molecules and their performance are correlated with the ternary interaction parameters, X_m3, and the Mark-Houwink-Sakurada exponent, a′. The adsorption changes observed are greater in those systems in which tetrahydrofuran was present.