The use of microwave irradiation for the easy synthesis of graphene-supported transition metal nanoparticles in ionic liquids

Stable ruthenium or rhodium metal nanoparticles were supported on chemically derived graphene (CDG) surfaces with small and uniform particle sizes (Ru 2.2 ± 0.4 nm and Rh 2.8 ± 0.5 nm) by decomposition of their metal carbonyl precursors by rapid microwave irradiation in a suspension of CDG in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. The graphene-supported hybrid nanoparticles were shown to be active and could be re-used at least 10 times as catalysts for the hydrogenation of cyclohexene and benzene under organic-solvent-free conditions with constant activities up to 1570 mol cyclohexane × (mol metal)⁻¹ × h⁻¹ at 4 bar and 75 °C.     

Bestimmung von Pentan als Indikator für die oxidative Ranzigkeit von Ölen

Determination of Pentane as an Indicator of Oil Rancidity Pentane, determined by a headspace gas chromatographic method, is an excellent indicator of oil rancidity. The methodology applied is very simple and could be performed in an oil laboratory without purchasing additional equipment. The amount of pentane correlated well with the iodometrically determined peroxide value (R²-value of 0.976). Heating the oil sample in air followed by an estimation of pentane is an alternative means to assess oil stability against oxidative deterioration.     

Measurement of fat content of food with single-sided NMR

Fat content is one of the important parameters of quality control in many food products. Several techniques are used to determine the amount of fat in a given product. In this work, the applicability of a portable dedicated nuclear magnetic resonance (NMR) analyzer to measure the fat content in a packaged product without destruction of the material was examined. Two different low-field NMR methods, namely, a ratio method and a relaxation time method, were applied and discussed. The processed NMR signal was linearly correlated with the fat content obtained by reference methods. The linear correlation allowed the application of single-sided NMR for fat measurements. In memoriam     

Modular phospholane ligands in asymmetric catalysis

This Account outlines the preparation and application of a class of phosphine ligands based upon the trans-2,5-disubstituted phospholane moiety. The modular nature of these ligands has allowed facile variation of both phospholane substituent and backbone structure, thus providing access to a series of ligands. Bidentate bis(phospholane) ligands have been found to be very useful in asymmetric catalytic hydrogenation reactions. In particular, we highlight the versatility of highly efficient bis(phospholane)rhodium catalysts that allow enantioselective hydrogenation to produce a diverse range of compounds containing C-N, C-O, and C-C stereogenic centers.     

Engineering the active center of the 6-phospho-{beta}-galactosidase from Lactococcus lactis

Several amino acids in the active center of the 6-phospho-ß-galactosidasefrom Lactococcus lactis were replaced by the corresponding residuesin homologous enzymes of glycosidase family 1 with differentspecificities. Three mutants, W429A, K435V/Y437F and S428D/K435V/Y437F, were constructed. W429A was found to have an improvedspecificity for glucosides compared with the wild-type, consistentwith the theory that the amino acid at this position is relevantfor the distinction between galactosides and glucosides. Thek_cat/K_m for o-nitrophenyl-ß-D-glucose-6-phosphate is 8-foldhigher than for o-nitrophenyl-ß-D-galactose-6-phosphatewhich is the preferred substrate of the wild-type enzyme. Thissuggests that new hydrogen bonds are formed in the mutant betweenthe active site residues, presumably Gln19 or Trp421 and theC-4 hydroxyl group. The two other mutants with the exchangesin the phosphate-binding loop were tested for their abilityto bind phosphorylated substrates. The triple mutant is inactive.The double mutant has a dramatically decreased ability to bindo-nitrophenyl-ß-D-galactose-6-phosphate whereas the interactionwith o-nitrophenyl-ß-D-galactose is barely altered. Thisresult shows that the 6-phospho-ß-galactosidase and therelated cyanogenic ß-glucosidase from Trifolium repenshave different recognition mechanisms for substrates althoughthe structures of the active sites are highly conserved.     

Demosaicing algorithms for area- and line-scan cameras in print inspection

Most color image sensors use color filter arrays (CFA). With this sensor design the captured information at each sensor pixel position is restricted to a specific spectral portion (typically red, green and blue bands). To obtain the missing color responses at each pixel position, so-called CFA demosaicing algorithms are commonly used. We propose two new CFA demosaicing algorithms, which are well suited for industrial print inspection with respect to the requirements in accuracy and speed. As a main contribution, we introduce novel demosaicing algorithms for specific high-speed color digital time delay and integration (DTDI) CFA line-scan cameras. We compare the suggested CFA demosaicing algorithms to state-of-the art algorithms for area and line-scan camera operation modes. We show that the two new algorithms perform superior to conventional algorithms as indicated by reconstruction error.     

Integration of beamforming and uncertainty-of-observation techniques for robust ASR in multi-source environments

This paper presents a new approach for increasing the robustness of multi-channel automatic speech recognition in noisy and reverberant multi-source environments. The proposed method uses uncertainty propagation techniques to dynamically compensate the speech features and the acoustic models for the observation uncertainty determined at the beamforming stage. We present and analyze two methods that allow integrating classical multi-channel signal processing approaches like delay and sum beamformers or Zelinski-type Wiener filters, with uncertainty-of-observation techniques like uncertainty decoding or modified imputation. An analysis of the results on the PASCAL-CHiME task shows that this approach consistently outperforms conventional beamformers with a minimal increase in computational complexity. The use of dynamic compensation based on observation uncertainty also outperforms conventional static adaptation with no need of adaptation data.