Fatty acid composition of danish margarines and shortenings,with special emphasis ontrans fatty acids

Trans fatty acids from hydrogenated vegetable and marine oils could be as hypercholesterolemic and atherogenic as saturated fatty acids. Hence, it is important to know the fatty acid composition in major food contributors, e.g., margarines and shortenings. In 1992 margarines were examined, and in 1995 brands covering the entire Danish market were examined. Significant amounts oftrans-18∶1 were found only in hard margarines (mean: 4.2±2.8%) and shortenings (mean: 6.8 ±3.1%), whereas the semisoft and soft margarines contained substantially lesstrans-18∶1 in 1995 than in 1992. Where marine oils had been used to a larger degree the meantrans-monoenoic content was about 15%, of which close to 50% was made up of long-chain (C₂₀ and C₂₂)trans fatty acids. A note-worthy decrease in the content oftrans-18∶1 had occurred for the semisoft margarines, from 9.8±6.1% in 1992 to 1.2±2.2% in 1995. Calculated from sales figures, the supply oftrans-18∶1 plus saturated fatty acids from margarines had decreased over this three-year period by 1.4 g/day, which has been replaced bycis monounsaturated and polyunsaturated fatty acids.     

Ambrosio-Tortorelli Segmentation of Stochastic Images: Model Extensions, Theoretical Investigations and Numerical Methods

We discuss an extension of the Ambrosio-Tortorelli approximation of the Mumford-Shah functional for the segmentation of images with uncertain gray values resulting from measurement errors and noise. Our approach yields a reliable precision estimate for the segmentation result, and it allows us to quantify the robustness of edges in noisy images and under gray value uncertainty. We develop an ansatz space for such images by identifying gray values with random variables. The use of these stochastic images in the minimization of energies of Ambrosio-Tortorelli type leads to stochastic partial differential equations for a stochastic smoothed version of the original image and a stochastic phase field for the edge set. For the discretization of these equations we utilize the generalized polynomial chaos expansion and the generalized spectral decomposition (GSD) method. In contrast to the simple classical sampling technique, this approach allows for an efficient determination of the stochastic properties of the output image and edge set by computations on an optimally small set of random variables. Also, we use an adaptive grid approach for the spatial dimensions to further improve the performance, and we extend an edge linking method for the classical Ambrosio-Tortorelli model for use with our stochastic model. The performance of the method is demonstrated on artificial data and a data set from a digital camera as well as real medical ultrasound data. A comparison of the intrusive GSD discretization with a stochastic collocation and a Monte Carlo sampling is shown.     

Grain Boundary Chemistry and Transport Through Alumina Scales on NiAl Alloys

Oxidation of Metals - It is widely accepted that the growth of protective α-Al2O3 scales on Ni-based alloys is governed by the inward diffusion of oxygen through the oxide grain boundaries...     

Degenerate Quantum Gases in Microgravity

Clouds of ultra-cold atoms and especially Bose–Einstein condensates (BEC) provide a source for coherent matter-waves in numerous earth bound experiments. Analogous to optical interferometry, matter-wave interferometers can be used for precision measurements allowing for a sensitivity orders of magnitude above their optical counterparts. However, in some respects the presence of gravitational forces in the lab limits experimental possibilities. In this article, we report about a compact and robust experiment generating Bose–Einstein condensates in the drop tower facility in Bremen, Germany. We also present the progress of building the succeeding experiment in which a two species atom interferometer will be implemented to test the weak equivalence principle with quantum matter.     

Sorption behavior of the MgH2–Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering

The hydrogen sorption behavior of the Mg₂FeH₆–MgH₂ hydride system is investigated via in-situ synchrotron and laboratory powder X-ray diffraction (SR-PXD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), particle size distribution (PSD) and volumetric techniques. The Mg₂FeH₆–MgH₂ hydride system is obtained by mechanical milling in argon atmosphere followed by sintering at high temperature and hydrogen pressure. In-situ SR-PXD results show that upon hydriding MgH₂ is a precursor for Mg₂FeH₆ formation and remained as hydrided phase in the obtained material. Diffusion constraints preclude the further formation of Mg₂FeH₆. Upon dehydriding, our results suggest that MgH₂ and Mg₂FeH₆ decompose independently in a narrow temperature range between 275 and 300 °C. Moreover, the decomposition behavior of both hydrides in the Mg₂FeH₆–MgH₂ hydride mixture is influenced by each other via dual synergetic-destabilizing effects. The final hydriding/dehydriding products and therefore the kinetic behavior of the Mg₂FeH₆–MgH₂ hydride system exhibits a strong dependence on the temperature and pressure conditions.     

Nanoconfinement degradation in NaAlH4/CMK-1

An ordered mesoporous carbon scaffold (CMK-1) has been synthesized and infiltrated with NaAlH₄ nanoparticles by solvent- and melt-infiltration techniques. Small angle X-ray scattering (SAXS), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and energy dispersive spectroscopy (EDS) are used to characterize the structure, composition and morphology before and after thermal treatment. This study illuminates some of the problems that can be associated with nanoconfinement of hydrogen storage materials including scaffold contamination, residual solvent contamination, sample morphology changes after heating, and other factors that can be detrimental to the application of these systems. Of particular interest is the expulsion of NaAlH₄ decomposition products from the scaffold after heating beyond its melting point under vacuum. This results in the surface of mesoporous carbon particles having arrays of multi-micron-long Al filaments that are >100 nm in diameter.     

Peptide profiles and angiotensin-I-converting enzyme inhibitory activity of fermented milk products: Effect of bacterial strain,fermentation pH,and storage time

Milk was fermented to defined pH values with 13 strains of lactic acid bacteria. The products were evaluated after 1 and 7 days of cold storage, and major peptides in selected products were identified. The Streptococcus thermophilus and Lactobacillus acidophilus strains used did not give rise to products with significant angiotensin-1-converting enzyme (ACE)-inhibition. The four Lactococcus lactis strains behaved similarly in fermentation, proteolysis and ACE-inhibition. The products made with the seven Lactobacillus helveticus strains varied. The highest ACE-inhibitory activity was obtained with two highly proteolytic strains of Lb. helveticus and with the Lactococcus strains. Fermentation from pH 4.6 to 4.3 with these strains slightly increased the ACE-inhibitory activity, whilst fermentation to pH 3.5 with Lb. helveticus reduced the ACE-inhibitory activity. Cold storage dramatically increased the ACE-inhibitory activity of some products. A non-linear correlation was found between peptide amount and ACE-inhibitory activity, and peptides contributing to the ACE-inhibitory activity were identified.