Comparison of RRR-α- and all-rac-α-tocopherol uptake by permanent rat skeletal muscle myoblasts (L6 cells): Effects of exogenous lipoprotein lipase

The purpose of the present investigation was to test whether permanent skeletal muscle cells (rat L6 cells) could serve as an in vitro model for α-tocopherol (αTocH) biodiscrimination studies. L6 cells were incubated in the presence of high density lipoprotein (HDL), low density lipoprotein (LDL), and very low density lipoprotein (VLDL) labeled in the lipid moiety with either all-rac-or RRR-[¹⁴C]αTocH. These incubations were performed either in the absence or in the presence of exogenously added bovine lipoprotein lipase (LPL) since skeletal muscle is one of the major expression sites of LPL in vivo. Time-dependent uptake studies (up to 24 h) in the absence of LPL have shown that equipotent doses of all-rac- and RRR-[¹⁴C]αTocH (1.36∶1) led to almost identical accumulation of the tracer, independent of the lipoprotein class used as αTocH carrier. With regard to αTocH donor capacity, it appeared that HDL is the most potent αTocH donor, followed by LDL and VLDL. In the presence of LPL, all-rac- and RRR-[¹⁴C]αTocH uptake was significantly enhanced (between two- and tenfold). Biodiscrimination studies using chiral high-performance liquid chromatographic analysis with radiometric detection of the corresponding methyl ether derivatives on a Chiralcel OD column have demonstrated that the 2S-and 2R-isomers of αTocH were taken up in a 1∶1 ratio by L6 cells independent of the absence or presence of LPL. In addition, we have not observed biodiscrimination between the four 2R-isomers, i.e., there was no preferential accumulation of the RRR-isomer. These data suggest that L6 cells do not discriminate between different αTocH isomers and that the addition of endogenous LPL significantly enhances the uptake of RRR- and all-rac-αTocH.     

Enhanced Catalytic Performance of Co/MFI by Hydrothermal Treatment

Hydrothermal treatment of Co/MFI catalysts at high temperature increases their performance for NO _x reduction with methane. As this treatment also shifts the TPR peak of isolated Co ions upward by 20 °C, the results suggest that the hydrothermal treatment induces transport of Co²⁺ ions from to positions.     

Coriolis mass flowmeters: Overview of the current state of the art and latest research

This paper is an update of the overview given by Baker RC [Coriolis flowmeters: Industrial practice and published information. Flow Meas Instrum 1994;5(4):229–46]. Overviews about mass flowmetering are also given in Baker RC [Flow measurement handbook. Cambridge University Press; 2000]. Furthermore, Drahm W and Linnartz H [Coriolis-massflowmeters: State of the art review and innovations. In: Proceedings FLUCOME 2003. 2003] reported about latest innovations in Coriolis technology.

The published information of the last decade is reviewed and the conclusions of the different papers are briefly described.     

Three-dimensional h-adaptivity for the multigroup neutron diffusion equations

Adaptive mesh refinement (AMR) has been shown to allow solving partial differential equations to significantly higher accuracy at reduced numerical cost. This paper presents a state-of-the-art AMR algorithm applied to the multigroup neutron diffusion equation for reactor applications. In order to follow the physics closely, energy group-dependent meshes are employed. We present a novel algorithm for assembling the terms coupling shape functions from different meshes and show how it can be made efficient by deriving all meshes from a common coarse mesh by hierarchic refinement. Our methods are formulated using conforming finite elements of any order, for any number of energy groups. The spatial error distribution is assessed with a generalization of an error estimator originally derived for the Poisson equation.Our implementation of this algorithm is based on the widely used Open Source adaptive finite element library deal.II and is made available as part of this library's extensively documented tutorial. We illustrate our methods with results for 2-D and 3-D reactor simulations using 2 and 7 energy groups, and using conforming finite elements of polynomial degree up to 6.     

Pyrazolonderivate. IV [9]. Zur Tautomerie und Stereochemie von 4-Aminomethylen-Δ2-pyrazolinonen-(5)

Pyrazolone Derivatives. IV. Tautomerism and Stereochemistry of 4-Aminomethylene-Δ²-pyrazolinones-(5) Tautomerism and stereochemistry of compounds of type 1 were investigated by ¹H-n.m.r.- and i.r.-spectroscopy. Dynamic ¹H-n.m.r. study with ¹⁵N-labelled compounds shows, that 1 exist in solution as 4-aminomethylene-Δ²-pyrazolinones-(5) with strong intramolecular hydrogen bonds. Compared to 4-unsubstituted Δ²-pyrazolinones-(5) polar solvents do not change the tautomeric equilibrium of 1 . The N-aryl-substituted compounds have a higher NH-acidity than N-alkyl-substituted derivatives. In crystalline state the N-alkyl-substituted compounds 1g, h exist in the E-configuration as 4-aminomethylene-Δ²-pyrazolinones-(5) with intermolecular hydrogen bond. At higher temperatures or in solution the Z-isomer is formed spontaneously.     

Analysis of the Processing-Pressure Dependent Refractive Index of Polycarbonate by Transmission Measurements of Glass-Filled Specimen

In this study, the influence of pressure during processing on the refractive index (RI) of polycarbonate (PC) was investigated by transmission measurements on glass-filled samples with a spectrometer. In order to isolate the pressure dependence of the RI from other influencing parameters such as cooling rate, orientation and stress states, the samples were prepared in a pressure-specific volume-Temperature (pvT) instrument under constant cooling rate and temperature history and without shear effects. Subsequently, the RI was determined at the intersection of the dispersion curves of the glass and the polymer by evaluating the wavelength of the maximal transmission of the samples. The mean RI over the entire cross section of the sample is determined by the transmission measurements without complex sample preparation. The investigations show that the RI of PC increases by 3.26 E-6 per bar with increasing pressure. POLYM. ENG. SCI., 60:512–516, 2020. © 2019 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.     

Identification of benzalkonium chloride in food additives and its inefficacy against bacteria in minced meat and raw sausage batters

There is a growing market for 'natural' food preservatives though their active ingredients are poorly known. We analysed four such additives, Bacterin, Protecta One, Protecta Two and Protecta Three, marketed as effective preservatives for meat products on the basis of salts and extracts of 'natural herbs'. Their ingredients were separated by HPLC and the structures of the antimicrobially active components were determined by mass spectrometry. The products contained the disinfectant benzalkonium chloride, an antimicrobial quaternary ammonium compound, as the only active principle. HPLC methods are reported for the analysis of benzalkonium chloride in such products and in meat. Bacterin and Protecta One, as well as pure benzalkonium chloride in equivalent concentrations, did not show antibacterial effects against meat-relevant pathogens in minced meat and raw sausage batter. Because benzalkonium chloride is not a permitted food additive, and is not effective as a preservative in meat, the public should be cautioned against such products alleged to contain 'natural herb extracts'.     

Stability of a system with nonlinear nonautonomous feedback

A sufficient stability condition is presented for systems which contain a time-varying nonlinear feedback element. It is shown that it extends existing stability criteria. The application of the criterion to a numerical example is given.     

Mutations in the EXT1 and EXT2 genes in hereditary multiple exostoses

In an in-vitro preparation of gastric mucosae of Rana pipiens, the effect of adding melittin to a concentration of 5x10-6 M in the secretory solution on the transepithelial potential difference (PD), resistance (R) and short-circuit current (Isc) was studied. In 20 min, melittin decreased the PD by 9.3 mV and R by 148 ohm cm2. These changes can be explained by a decrease in the resistance, RP, of the paracellular pathway. To determine whether specific-ion pathways were responsible for the decrease in R, the effect of melittin on the partial conductances of Cl-, K+ and Na+ was also studied using the ion substitution method. Melittin decreased the PD response to changes in nutrient Na+, K+ and Cl- and the PD response to changes in secretory Cl-, but did not affect PD responses to changes in secretory Na+ or K+. Therefore, melittin decreased the nutrient membrane partial conductances of Cl-, K+ and Na+ and secretory membrane partial conductance of Cl-, without affecting the secretory partial conductances of Na+ or K+. Initially, melittin increased Isc in regular and Cl--free but not in Na+-free solutions. There was a delayed decrease in Isc. The results indicate that melittin decreases RP, increases the Na+ conductance of the secretory membrane and inhibits, eventually, the Na+/K+-ATPase pump.