Polymer derived ceramic materials from Si,B and MoSiB filler-loaded perhydropolysilazane precursor for oxidation protection

Silica-based coating systems were developed using polymer derived ceramics (PDCs) technology. Ceramic composites on the base of a SiO₂ and SiNO matrix and homogeneously distributed Mo₅SiB₂, SiB₆, Si and B fillers were manufactured. The coating systems have low porosity and provide a high oxidation resistance up to 100 h at 800 °C and 1100 °C in air. The influence of temperature and atmosphere of pyrolysis on the polymer precursor, the volume fraction of filler materials on the chemical composition of compacts as well as their high-temperature oxidation protection was investigated.     

Effect of Powder Processing and Sintering Conditions on the Microstructural,Thermal, and Mechanical Properties of Reticulated Zinc Oxide Ceramic Foams

Ceramic foams are made of zinc oxide using different amounts of Sb₂O₃ and Bi₂O₃ as sintering aids. The effect of a ball milling processing of the starting powders and the sintering temperature on the microstructure and the properties of the ZnO foams is investigated. The focus is set on the evolution of the secondary phases formed within the microstructure of ZnO. A determining effect is identified in the amount of an Al₂O₃ impurity which is introduced by abrasion of the milling vessels during ball milling. Alumina is partially dissolved in a spinel α–Zn₇Sb₂O₁₂ secondary phase which is stabilized by a reduction of the unit cell volume. Remaining Al₂O₃ is incorporated into zinc oxide under formation of a defect wurtzite phase. The phase evolution is a complex function of the content of sintering aids, the Al₂O₃ impurity level and the sintering temperature. The shrinkage during sintering and the porosity evolution are correlated to the phase composition within the ZnO material. The thermal conductivity and the compressive strength of the foams are determined, normalized with respect to their porosity, and correlated to the microstructure and phase composition of the ZnO strut material.     

Non-linear Stationary Spin-waves in Superfluid 3He-B at Ultra-low Temperatures

We have performed detailed CW NMR measurements on superfluid ³ He-B in order to investigate stationary spin-wave modes in a texture well. Our results at high temperatures are consistent with previous work. However, we find that the spin dynamics is profoundly modified, even for small excitation amplitudes, for temperatures on the order of 200 K, substantially lower than the limit reached in previous investigations. We report the observation of non-linear spin-waves at ultra-low temperatures and their characterization in terms of a third-order anharmonic oscillator.     

TCMI: a non-parametric mutual-dependence estimator for multivariate continuous distributions

Data Mining and Knowledge Discovery - The identification of relevant features, i.e., the driving variables that determine a process or the properties of a system, is an essential part of the...     

Limitations of rapid myelin water quantification using 3D bSSFP

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Imaging of the myelin water fraction (MWF) is conventionally performed using a multi-echo spin-echo sequence. This technique requires long acquisition times and therefore often suffers from a lack of volume coverage. In this work, the application of 3D balanced steady-state free precession (bSSFP) sequences to extract high-resolution myelin water maps is discussed.     

High glycolytic potential does not predict low ultimate pH in pork

Extent of postmortem pH decline influences meat quality development. To better understand physiological determination of ultimate pH (pH_u), we utilized female and castrated male pigs from a line whose selection index includes differentiated pH_u. All genotypes of AMP-activated protein kinase γ3 subunit (AMPKγ3) V199I site were present. The mutant 199II genotype increased pH_u, but only in castrated males. Genotype affected glycolytic potential (GP), but GP was weakly associated with pH_u. A subset of animals was selected based on low (− Gly) and high (+ Gly) residual glycogen content, and compared with AMPKγ3 200Q, which is associated with low pH_u. Both + Gly and 200Q muscle contained glycolytic substrate at 24 h; however, 200Q muscle generated low pH_u and greater lactate compared to + Gly. Additionally,− Gly and + Gly groups exhibited similar pH_u despite a large difference in GP. In conclusion, high GP does not appear to directly impact the extent of postmortem pH decline.     

Characterization of the human SDHC gene encoding of the integral membrane proteins of succinate-quinone oxidoreductase in mitochondria

The neurological manifestations of multiple sclerosis (MS) have been considered to result from demyelination of axons with relative preservation of axonal integrity. This concept has been challenged recently by a landmark pathological study, published in the New England Journal of Medicine, which has demonstrated that axonal degeneration is also present. The authors of the study hypothesized that axonal degeneration is the pathological correlate of the irreversible neurological impairment in this disease. However, this hypothesis cannot be reconciled with the clinical results obtained with transcranial applications of AC pulsed electromagnetic fields (EMFs) of picotesla flux density which have shown rapid and sustained improvement of symptoms including normalization of evoked potential responses in patients with chronic progressive or secondary progressive MS without demyelinated areas first undergoing remyelination or transected axons undergoing regeneration. Biochemical studies have shown that MS patients are serotonergically depleted with the extent of cerebral depletion correlating with the degree of motor disability and a chronic progressive course. It is believed that progressive serotonergic neuronal atrophy with synaptic inactivation, not axonal degeneration, are the hallmarks of the disease and that administration of AC pulsed magnetic fields improves symptoms of MS partly through reactivation of serotonergic neurons and amplification of synaptic serotonergic transmission.     

Bindemittelfreie zeolithische Molekularsiebe der Typen LTA und FAU

Zeolite molecular sieves belong to the most important adsorbents. For dynamic, technical adsorption processes the use of shaped bodies is required. In conventional molecular sieves usually clay type minerals are used as binder. In this paper novel binderless zeolite molecular sieves and their advantages in comparison to binder containing molecular sieves are shown.