An algorithm for computing compatibly Frobenius split subvarieties

This paper describes an algorithm which produces all ideals compatible with a given surjective Frobenius near-splitting.     

Effect of Lowering Asymmetric Dimethylarginine (ADMA) on Vascular Pathology in Atherosclerotic ApoE-Deficient Mice with Reduced Renal Mass

The purpose of the work was to study the impact of the endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) and its degrading enzyme, dimethylarginine dimethylaminohydrolase (DDAH1), on atherosclerosis in subtotally nephrectomized (SNX) ApoE-deficient mice. Male DDAH1 transgenic mice (TG, n = 39) and C57Bl/6J wild-type littermates (WT, n = 27) with or without the deletion of the ApoE gene underwent SNX at the age of eight weeks. Animals were sacrificed at 12 months of age, and blood chemistry, as well as the extent of atherosclerosis within the entire aorta were analyzed. Sham treated (no renal mass reduction) ApoE-competent DDAH1 transgenic and wild-type littermates (n = 11) served as a control group. Overexpression of DDAH1 was associated with significantly lower ADMA levels in all treatment groups. Surprisingly, SNX mice did not exhibit higher ADMA levels compared to sham treated control mice. Furthermore, the degree of atherosclerosis in ApoE-deficient mice with SNX was similar in mice with or without overexpression of DDAH1. Overexpression of the ADMA degrading enzyme, DDAH1, did not ameliorate atherosclerosis in ApoE-deficient SNX mice. Furthermore, SNX in mice had no impact on ADMA levels, suggesting a minor role of this molecule in chronic kidney disease (CKD) in this mouse model.     

Proteome Analysis of Subsarcolemmal Cardiomyocyte Mitochondria: A Comparison of Different Analytical Platforms

Mitochondria are complex organelles that play critical roles in diverse aspects of cellular function. Heart disease and a number of other pathologies are associated with perturbations in the molecular machinery of the mitochondria. Therefore, comprehensive, unbiased examination of the mitochondrial proteome represents a powerful approach toward system-level insights into disease mechanisms. A crucial aspect in proteomics studies is design of bioanalytical strategies that maximize coverage of the complex repertoire of mitochondrial proteins. In this study, we evaluated the performance of gel-based and gel-free multidimensional platforms for profiling of the proteome in subsarcolemmal mitochondria harvested from rat heart. We compared three different multidimensional proteome fractionation platforms: polymeric reversed-phase liquid chromatography at high pH (PLRP), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and isoelectric focusing (IEF) separations combined with liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), and bioinformatics for protein identification. Across all three platforms, a total of 1043 proteins were identified. Among the three bioanalytical strategies, SDS-PAGE followed by LC-MS/MS provided the best coverage of the mitochondrial proteome. With this platform, 890 proteins with diverse physicochemical characteristics were identified; the mitochondrial protein panel encompassed proteins with various functional roles including bioenergetics, protein import, and mitochondrial fusion. Taken together, results of this study provide a large-scale view of the proteome in subsarcolemmal mitochondria from the rat heart, and aid in the selection of optimal bioanalytical platforms for differential protein expression profiling of mitochondria in health and disease.     

Coking behavior of nickel and a rhodium based catalyst used in steam reforming for power-to-gas applications

This paper proposes partial steam reforming of natural gas as a chemical storage option for excess electricity. Thermodynamic simulations with Aspen Plus^® show that highest process efficiencies are reached at low steam-to-carbon (S/C) ratios in the feed. However, coke deposition due to unwanted side or follow-up reactions and thus catalyst deactivation is likely in this operation range. In an experimental evaluation three catalysts were selected to test their resistance towards coking: two nickel based and one rhodium based noble metal catalyst. They were tested regarding their long-term stability at S/C ratios as low as 0 to 0.1 and reaction temperatures between 450 and 500 °C. A different reaction and deactivation behavior was observed for nickel and the noble metal catalysts. The measured life times of the noble metal catalyst were by a factor of at least 100 higher than for the two selected nickel catalysts at the applied reforming conditions. Furthermore, after each reforming experiment, a temperature-programmed oxidation (TPO) analysis was performed for the spent catalysts. Based on literature data, the measured CO₂ peaks at corresponding temperatures were related to the different forms of solid carbon depositions. Main carbonaceous species found on the nickel catalysts were of filamentous nature, whereas one or two more reactive C species with monoatomic or polymeric structure at much lower amount were detected on the noble metal catalyst. Further SEM analysis confirmed these findings.     

Atmospheric trace gas analysis with cavity ring-down spectroscopy

Cavity ring-down spectroscopy (CRDS) is a highly sensitive laser absorption method. It can be used for quantitative analysis of molecular species at the sub-ppb level. The absorption cell (cavity) is sealed by two high-reflective mirrors on each side, which results in an effective absorption path-length of some kilometers. Our experiments for atmospheric gas analysis have been carried out so far with an Excimer pumped dye laser in the UV-VIS and a CO overtone sideband laser in the wavelength region around 3 μm. Experiments with an all solid-state difference frequency laser system will follow. In the UV-VIS region, we measured trace gas molecules like SO₂, NO₂, and CH₂O. In the mid-infrared, around 3 μm, we measured hydrocarbons like CH₄, C₂H₆, and C₂H₄ with a detection limit of less than 1 ppb. The noise equivalent absorption coefficients in the MIR are in the order of 1.7·10⁻⁹ cm⁻¹. Due to the high data acquisition rate and the high sensitivity, CRDS enables real-time detection of trace gases in ambient air.     

Incorporation of postconsumer polyurethane foam into a polymer/clay aerogel matrix

The feasibility of incorporating ground recycled polyurethane (PU) foam into clay/polymer aerogels was demonstrated, and a range of compositions were prepared and characterized to determine the effect of variation in the formulations on density and mechanical properties of the resulting materials. This study followed a modified combinatorial approach. Initially, experiments were performed in water using either sodium exchanged montmorillonite or laponite clay, poly(vinyl alcohol) (PVOH) solution as the polymer binder, and the recycled PU foam. Freezing and freeze‐drying the aqueous gels produced aerogels, which were characterized through density and mechanical testing, scanning electron microscopy, and thermal gravimetric analysis. The study was expanded by exploring alternative binder chemistries, including the use of an alginate polymer in place of the PVOH or adding a polyisocyanate as a crosslinking agent for PVOH. The effect of recycled PU foam content, clay type and level, and binder type and level on the mechanical properties of the aerogels were determined and will be discussed herein. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42586.     

Katalysatoren des Leuna Werkes 1945 – 1988: Von der Empirie zur Wissenschaft. Teil III: Hydroraffinationskatalysatoren

Focus of the two preceding papers within this publication series were the development and manufacturing of technical catalysts at the Leuna Werke company from 1921 – 1945 (part I) and 1950 – 1991 (part II) for the reforming and isomerization catalysts. This article describes the genesis of the hydrofining group of catalysts as cornerstones of the GDR economy. 36 catalysts and 15 special aluminum oxides, X‐ray amorphous as well as crystalline aluminum silicates, were developed and brought into service for the Leuna hydrogenation and other refineries. During that time, a vast knowledge base was generated; new chemical processes were pioneered and equipped with tailor‐made catalysts developed in Leuna.