Dietary and host-related factors influencing carotenoid bioaccessibility from spinach (Spinacia oleracea)

Several dietary and host related factors potentially influencing carotenoid (beta-carotene, lutein and zeaxanthin) bioaccessibility from spinach, including different concentrations of sodium, calcium and magnesium, were systematically investigated by means of an in vitro digestion model. Bioaccessibility was highest when milk (4% fat) and lowest when skimmed milk or more complex food matrices such as sausage were added to the meal. Micellarisation significantly depended on the presence and concentration of bile salts and pancreatin (p < 0.001, Bonferroni) but was unaffected by pepsin. Micellarisation significantly decreased to 61.4 ± 3.0% of control (p < 0.001, Dunnett’s) at high cholesterol (114 mg/test meal) but not at similar stigmasterol concentrations. Calcium and magnesium ?13.8 mM individually inhibited micelle formation ( >40% on average), presumably due to the generation of insoluble soaps with fatty acids and bile salts. Increased sodium concentrations (280 and 460 mM) altered carotenoid micellarisation patterns, favoring beta-carotene isomers (p < 0.001, Bonferroni) but decreasing lutein and zeaxanthin (p < 0.001 and p < 0.05, respectively, Bonferroni). This study suggests that minerals may impact carotenoid bioavailability.     

Dispersion polymerization of styrene in CO2-expanded ethanol

Dispersion polymerization of styrene has been performed in CO₂-expanded ethanol at ≤9 MPa and 70 °C using PVP as stabilizer. The polymerizations proceeded with good colloidal stability, resulting in spherical particles of diameters of ∼2 μm. Pressurization with CO₂ leads to an increase in particle size (∼1 μm in the corresponding CO₂-free system), and a decrease in both polymerization rate and molecular weight. The main effect of CO₂ is proposed to be its influence on the partitioning of monomer between the continuous and the particle phase–the results indicate that CO₂-pressurization causes a reduction in monomer concentration in the particles. Overall, the results are consistent with literature data on the effects of the polarity of the continuous phase in dispersion polymerization of styrene in alcohols and alcohol/water mixtures.     

Synthesis of versatile TIPNO-based alkoxyamines

The versatile chloromethyl TIPNO-based alkoxyamine was efficiently transformed into other valuable functionalised TIPNO-based alkoxyamines such as amino alkoxyamines which are interesting initiators for block copolymers and bisalkoxyamines in good yield and in two steps at the most. One bisalkoxyamine has allowed to prepare well-defined polystyrene-b-poly(n-butyl acrylate)-b-polystyrene symmetrical triblock copolymer. The last representative example of such alkoxyamines is a styrenic alkoxyamine which was copolymerized with styrene to afford branched polystyrene. Finally, for the first time branched poly(n-butyl acrylate) by nitroxide mediated radical polymerization was obtained and was a efficient macroinitiator of styrene, which indicates that the radical polymerization mediated by this styrenic alkoxyamine is living.     

Sociogenèse et psychobiologie: Les sources de la continuité et de la discontinuité du développement.

The aim of this article is to reflect conceptually upon the various stakes in development from both psychobiological and sociogenetical perspectives, two prominent contemporary theories of social sciences. Where does developmental continuity belong?...Does it belong within the individual or within his or her environment? Despite explicitly recognizing the influence of social experience in human development, the traditionally old nature-nurture debate remains at the center of theoretical analyses and leads to a futile integration of the two positions. The authors propose a theoretical model, which suggests not to integrate these two antagonistic positions but rather to recognize and utilize their interdependency as a means of viewing continuity and discontinuity as complementary facets of development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Weibull Parameters and the Tensile Strength of Porous Phosphate Glass-Ceramics

The strengths of porous phosphate glass-ceramic specimens, with relative densities ranging between 0.25 and 0.50, were measured by four-point bending at room temperature. An analysis of the data, using Weibull statistics, indicated that such a treatment, usually performed on dense ceramics, can also be used on porous materials. In the sets studied, the nature of critical flaws was determined, which led to the proposal of a mechanism of fracture initiation in such porous materials.     

Stress-strain relationships in uniaxial extension of high cis-1,4-polyisoprene networks with different molecular weight precursors

Equilibrium stress-strain relationships in uniaxial extension for high cis-1,4-polyisoprene (Shell IR 307) networks were obtained by extrapolation of relaxation measurements to infinite time through a BKZ constitutive equation. Three series of networks were investigated, each series being characterized by its polymer precursor molecular weight. Influence of crosslinking density was studied through varying amounts of dicumyl peroxide as crosslinking agent. These results were used to test Flory and Erman's recent molecular elasticity theory of imperfect networks with constraints on junctions. It was shown that this later theory treating entanglements as restrictions on junction fluctuations could be reasonably used to characterize network topology. A universal value of 0.50 for the interpenetration parameter I is confirmed and an interpretation of parameter ζ in terms of network inhomogeneity is tentatively given.     

Effects of low‐frequency drain termination and injection on nonlinear amplifier performances

Low‐frequency parameters have important effects on the nonlinear performances of power amplifiers. Injection at the output of a low‐frequency‐voltage device, following the signal envelope, is proposed. Two‐tone simulations, measurements using the principle of a low‐frequency active load‐pull system, and implementation of the technique are presented. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Influence of material superficial moisture on insulation-metalelectroseparation

The efficiency of electroseparating the constituents of a polyvinyl chloride (PVC)-metal (aluminium or copper) granular mixture depends on the moisture content of the materials. Laboratory research has been accomplished in order to determine the acceptable superficial humidity of the granules to be separated. The experimental study has been carried out on a roll-type laboratory separator with corona-electrostatic field. Ten samples of 50% PVC and 50% aluminum or copper, with a moisture content in the range 0相似文献   

Improvement of mass transfer coefficient in reverse osmosis by oscillatory flow

This paper describes a laboratory apparatus for confined feed liquid reverse osmosis operation. In this apparatus, the mass transfer coefficient on the high pressure side of the membrane is increased by sweeping the membrane surface at a predetermined frequency by a back and forth movement of the feed liquid itself through an adjustable narrow channel in the cell. The utility of the technique for improving membrane performance is illustrated.     

An analysis of the relative errors in measuring the number of theoretical plates in a continuous distillation column

A general error function is derived which permits an examination of the accuracy of the heat of evaporation, the relative volatility, the analysis of the samples and the internal reflux ratio on the estimate of the number of theoretical trays required for a given change of the composition in a continuous rectification column. The error function published by Peacock can be derived as a special case. The examination shows that the accuracy of the estimate is mainly determined by the accuracy of the internal reflux ratio and especially the analysis of the samples. The best range for experiments is situated around an internal reflux ratio of one. An increase in relative volatility narrows this experimental range.