Modification of lysine amino groups by the lipid peroxidation product 4,5(E)-Epoxy-2(E)-hepteal

The reaction between 4,5(E)-epoxy-2(E)-heptenal (EH) andl-lysine was studied to characterize some of the compounds that may be produced when proteins react with peroxidizing lipids. A mixture of EH and lysine was incubated overnight at room temperature and then fractionated by high-performance liquid chromatography (HPLC). Fractions were freeze-dried and characterized by¹H and¹³C nuclear magnetic resonance (NMR) and mass spectrometry. Four major pyrrole derivatives were obtained, namely 1-(5′-amino-1′-carboxypentyl)-pyrrole (3), 1-(5′-amino-1′-carboxypentyl)-2-(1″-hydroxypropyl)pyrrole (diastereomers 5 and 8), 1-(5′-amino-5′-carboxypentyl)pyrrole (7), and 1-(5′-amino-5′-carboxypentyl)-2-(1″-hydroxypropyl)pyrrole (9). In addition, several lysine complexes were detected. A polymer (1b) that was responsible for the color and the fluorescence produced in the reaction was isolated by gel filtration chromatography from a fraction obtained by HPLC. Formation of pairs of analogs (5 and 3, 9 and 7) with and without a substituent in position 2 of the pyrrole ring suggested that the compounds were produced by the same mechanism, with the formation of the 2-unsubstituted pyrroles corresponding to the loss of the 2-substituent as propanal; propanal was detected by headspace capillary gas chromatography. A reaction mechanism is proposed based on the NMR data obtained when the reaction was monitored in real time in an NMR tube. The results suggest that pyrrolic amino acids 7 and 9 may be present in proteins that have been damaged by peroxidizing lipids.     

Effect of environmental temperature changes on rat liver fatty acid desaturases

Female rats warm-adapted at 30–32 C for 20–25 days and then shifted to 13–15 C for 12, 24, 48, 72 and 120 hr showed that Δ9 desaturase and fatty acid synthetase activity decay after 24 hr of cold exposure, while Δ6 and Δ5 desaturases were increased after this period of time. These results were confirmed by an increase of arachidonic acid of heart and liver microsomes phosphatidylcholine and a decrease of oleic acid. Neither NADH-cyt b₅ reductase nor NADH-cyt c reductase activity of liver microsomes were significantly affected. Male rats warm-adapted under the same conditions and then shifted to 13–15 C for 120 hr did not show significant changes in fatty acid synthetase, Δ9 and Δ6 desaturases and enzymes of the microsomal electron transport chain. Therefore, the desaturase response to environmental temperature changes could be plausibly linked to female hormones.     

Sn doped GeO(2) nanowires with waveguiding behavior

Sn doped GeO(2) nanowires and microwires have been grown by an evaporation-deposition method, using a mixture of Ge and SnO(2) powders as precursors. Comparison with undoped GeO(2) nanowires grown by the same method shows that the presence of Sn prevents the formation of sharp bends, which makes the wires more suitable for waveguiding applications. Incorporation of about 0.5?at.% of Sn into the wires influences their morphology and gives rise to wires showing two different cross-sectional dimensions along the growth axis. Sn does not influence the luminescence spectra in the visible range but causes the appearance of emission bands in the near-infrared range. The waveguiding behavior of the Sn doped wires for green and red laser light has been demonstrated.     

Phase stability analysis using the PC-SAFT equation of state and the tunneling global optimization method

Phase stability calculation is a very important topic in phase equilibrium modeling. Usually the phase stability problem is solved by minimization of the tangent plane distance (TPD) function, the sign of the objective function at its global minimum indicating the state of the mixture at given conditions. The TPD function is non-convex and may be highly non-linear, many phase stability problems being really challenging. The tunneling global optimization method had been successfully used for solving a variety of phase equilibrium problems, including stability, with cubic equations of state (EoS). In this work, we test the ability of the tunneling method to solve the phase stability problem for more complex EoS like PC-SAFT. Calculations are performed for several benchmark problems, for mixtures of non-associating molecules, from binaries to multicomponent. In one example, the mixture contains hydrogen sulphide, for which the three parameters required by the PC-SAFT EoS were unavailable in the literature. These parameters, as well as the binary interaction parameter (BIP) between hydrogen sulphide and methane, were calculated based on experimental data.     

Experimental Correlation between Mechanical Non‐Linearity in LAOS Flow and Capillary Flow Instabilities for Linear and Branched Commercial Polyethylenes

An experimental correlation between the non‐linear behaviour of commercial polyethylene melts in LAOS flow, and the pressure fluctuations associated with melt flow instabilities developed in capillary rheometry are presented. Polyethylene melts with enhanced non‐linear behaviour under LAOS conditions present larger pressure fluctuations during capillary extrusion, and consequently, larger surface distortions on the extrudate. The combination of both methods can be a tool to predict the development of melt flow instabilities in the extrusion process of polyethylene melts, and can elucidate their correlation with material structural properties ( , MWD and topology).

     

Analysis of the optical field on the human retina from wavefront aberration data

Wave aberrations in the human eye are usually known with respect to the ideal spherical wavefront in the exit pupil. Using Kirchhoff's diffraction theory, we have derived a diffraction integral to compute the optical field on the retina from the wave aberration data. We have proposed a numerical algorithm based on the Stamnes-Spjelkavik-Pedersen (SSP) method to solve that integral. We have shown which approximations are admissible to reduce the complexity of the diffraction integral. In addition, we have compared our results with those of the conventional procedure used to compute intensities on the retina. We have found significant differences between our results and the conventional ones.     

Nonparametric tests for model selection with time series data

We consider a test for the selection of variables/covariates in a time series regression model based on aL ₂-measure of global deviation between the nonparametric estimates of the regression model obtained under the null and alternative hypotheses. Thus, the test can be viewed in the context of dimension reduction. Moreover, the test only requires, unlike others proposed for the same hypothesis testing problem, the choice of one bandwidth parameter. We show that our test has power against contiguous alternatives that converge to the null at a rateT ^−α, in contrast to alternative tests whose rates areT ^-α1, where 1/4 < α₁ < α 1/2. Thus the asymptotic relative efficiency of their test compared to ours is zero. Finally, the test is extended to the situation when the null follows a parametric model up to a finite set of parameters. This article is based on research funded by the Economic and Social Research Council (ESRC) reference number: R000235892.     

Effects of voucher-based intervention on abstinence and retention in an outpatient treatment for cocaine addiction: A randomized controlled trial.

The aims of this study were to assess whether voucher magnitude improved cocaine abstinence and retention in an outpatient treatment for cocaine dependence, and to determine the effectiveness of a contingency management intervention in a European cultural context. A randomized controlled trial was conducted in which 96 participants who were randomly assigned to 1 of 3 treatment conditions in a community setting: standard outpatient treatment, community reinforcement approach (CRA) plus low monetary value vouchers (each point earned was equivalent to 0.125? US$ 0.18), and CRA plus high monetary value vouchers (each point was worth 0.25? US$ 0.36). In the standard treatment group, mean percentage of cocaine-negative samples was 88.45%, versus 96.09% in the CRA plus low-vouchers group, and 97.07% in the CRA plus high-vouchers group. Retention rate at 6 months was 36.5% in the standard treatment group, 53.3% in the CRA plus low-vouchers group, and 69.0% in the CRA plus high-vouchers group. The CRA plus vouchers groups obtained better results than the standard program. This study showed that treating cocaine addiction by combining CRA with vouchers was more effective than standard treatment in community outpatient programs in Spain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis of Polymer‐Supported Fesulphos Ligands and their Application in Asymmetric Catalysis

The synthesis of two Fesulphos‐based chiral ligands and their immobilization on a polystyrene support is described. These supported chiral ligands act as very efficient catalysts in 1,3‐dipolar cycloaddition and allylic substitution reactions providing the products with excellent enantioselectivities (91 to >99 % ee). Filtration of the catalyst from the reaction mixtures allows simple product isolation. The polymer‐supported Cu complex of chiral ligand PS‐ 8 can be recycled without further addition of a copper salt in 1,3‐dipolar cycloaddition reactions.