Versuchsplanerische Untersuchung der Umesterung von Sojaöl mit Ethanol im Mikroreaktor

Base‐catalyzed transesterification of fats and oils with primary alcohols in discontinuous operation is an established batch process for the biodiesel production. However, the application of microreaction technology and continuous flow process lead to an increase of process intensification. The ethanol/soy bean oil ratio at low flow rates as well as the reactor geometry have the most evident effects on the fatty acid ethyl ester yield of KOH‐catalyzed ethanolysis of soy bean oil in microreactors. The influence of the catalyst concentration is of a lower importance.     

Monte Carlo Simulation of the Neurofilament Brush

Grand canonical Monte Carlo (MC) simulations are performed to analyse conformations of projection domains in a neurofilament (NF) brush composed of three types of tails (L, M, and H) at different concentrations of added salt. The NF is modelled as a rigid, uniformly charged cylinder (backbone), surrounded by tethered, flexible polyampholytic chains with charge distributions and stoichiometry similar to those in natural NFs. We calculate the equilibrium trajectory for each projection; that is, the average distance of the amino acid residue from the surface of the backbone as a function of its ranking number. These trajectories demonstrate the tendency for projections to fold back and adopt loop-like conformations at moderate solution salinities. We also perform extended analysis of MC data to identify metastable states of the system, and demonstrate representative snapshots of tail conformations in major metastable states.     

Complex Formation of Divalent Cations with Carboxylic Acid Resins as a Factor Determining Different Stationary States of Their Swelling

Three samples of carboxylic acid gel-type cross-linked polyelectrolytes were examined by registering the extent and kinetics of their volume change depending on the temperature, concentration, and nature of external electrolyte solutions, as well as the initial state (ionic form, water content) of the bead. It is found that in some systems the swelling of the bead (as a result of lowering the temperature) proceeds much more slowly than the preceding shrinking (as a result of the increase of temperature). Moreover, the initial volume of the bead is not restored, and a new stationary state of swelling is established. By means of optical dilatometry, it is found that in the systems in which the differences in the stationary states of swelling are found, the beads display plasto-elastic properties, whereas in the absence of such differences the beads show elastic properties. It is found that different stationary states of swelling are also established when the beads of copolymer of methacrylic acid cross-linked with divinylbenzene in Na⁺ form in the dry state and in the NaCl solution-swollen state are placed into a solution of a divalent cation salt. The difference in the stationary states of swelling reaches 12% in 4 N NiCl₂ solution. The substantial differences in the swelling behavior and viscoelastic properties of the resins in their Na⁺, Mg²⁺, Ca²⁺, and Ni²⁺ forms are interpreted in terms of formation of different kinds of complexes of functional groups of the polymer with Ca²⁺ and Ni²⁺ ions.     

Comparative Effects of Deferiprone and Salinomycin on Lead-Induced Disturbance in the Homeostasis of Intrarenal Essential Elements in Mice

Lead (Pb) exposure induces severe nephrotoxic effects in humans and animals. Herein, we compare the effects of two chelating agents, salinomycin and deferiprone, on Pb-induced renal alterations in mice and in the homeostasis of essential elements. Adult male mice (Institute of Cancer Research (ICR)) were randomized into four groups: control (Ctrl)—untreated mice administered distilled water for 28 days; Pb-exposed group (Pb)—mice administered orally an average daily dose of 80 mg/kg body weight (BW) lead (II) nitrate (Pb(NO₃)₂) during the first two weeks of the experimental protocol followed by the administration of distilled water for another two weeks; salinomycin-treated (Pb + Sal) group—Pb-exposed mice, administered an average daily dose of 16 mg/kg BW salinomycin for two weeks; deferiprone-treated (Pb + Def) group—Pb-exposed mice, administered an average daily dose of 20 mg/kg BW deferiprone for 14 days. The exposure of mice to Pb induced significant accumulation of the toxic metal in the kidneys and elicited inflammation with leukocyte infiltrations near the glomerulus. Biochemical analysis of the sera revealed that Pb significantly altered the renal function markers. Pb-induced renal toxicity was accompanied by a significant decrease in the endogenous renal concentrations of phosphorous (P), calcium (Ca), copper (Cu) and selenium (Se). In contrast to deferiprone, salinomycin significantly improved renal morphology in Pb-treated mice and decreased the Pb content by 13.62% compared to the Pb-exposed group. There was also a mild decrease in the renal endogenous concentration of magnesium (Mg) and elevation of the renal concentration of iron (Fe) in the salinomycin-treated group compared to controls. Overall, the results demonstrated that salinomycin is a more effective chelating agent for the treatment of Pb-induced alterations in renal morphology compared to deferiprone.     

Glass–Ceramic Composites with Strontium Hexaferrite Ultrafine Particles in the SrO–Fe2O3–B2O3–SiO2 System

Glass samples with nominal compositions SrFe₁₂O₁₉+(12− n )SrB₂O₄+nSrSiO₃, n =3, 6, 9 were prepared by rapid quenching of the melt. Processes of glass devitrification were studied. The samples were annealed at temperatures of 600–900°C, and the resulting glass–ceramics was characterized by XRD, SEM, EDX, and magnetic measurements. SrFe₁₂O₁₉ crystallizes above 700°C and forms nano- and submicron platelet particles with the aspect ratio depending on the thermal treatment conditions. The glass–ceramic samples annealed at 900°C show coercive force values in the range of 422–455 kA/m.     

Aluminum‐enhanced alkali diffusion from float glass to PVD‐sputtered silica thin films

Interdiffusion processes between aluminum enriched PVD‐sputtered silica thin films and industrial float soda‐lime silicate glass substrates are quantitatively studied using SIMS analysis. Heat treatments are performed at temperatures close or above the glass transition temperature of the float glass. Aluminum doping of the film is shown to strongly increase the migration of alkali from the glass substrate to the silica thin film. In particular the final alkali content in the film exhibits a linear scaling with the aluminum concentration. An interdiffusion process is evidenced between bulk alkali ions and protons originating from a significant water content in the as‐deposited silica film. Experimental measurements of sodium concentration are shown to be consistent with a simple thermodynamic model based on the equilibration of the activity of sodium between the film and the glass substrate.     

Complex of HIV-1 Integrase with Cellular Ku Protein: Interaction Interface and Search for Inhibitors

The interaction of HIV-1 integrase and the cellular Ku70 protein is necessary for HIV replication due to its positive effect on post-integration DNA repair. We have previously described in detail the Ku70 binding site within integrase. However, the integrase binding site in Ku70 remained poorly characterized. Here, using a peptide fishing assay and site-directed mutagenesis, we have identified residues I72, S73, and I76 of Ku70 as key for integrase binding. The molecular dynamics studies have revealed a possible way for IN to bind to Ku70, which is consistent with experimental data. According to this model, residues I72 and I76 of Ku70 form a “leucine zipper” with integrase residues, and, therefore, their concealment by low-molecular-weight compounds should impede the Ku70 interaction with integrase. We have identified such compounds by molecular docking and have confirmed their capacity to inhibit the formation of the integrase complex with Ku70. Our data demonstrate that the site of IN binding within Ku70 identified in the present work may be used for further search for inhibitors of the integrase binding to Ku70.