Administration of ferrocene-modified amino acids induces changes in synaptic transmission in the CA1 area of the hippocampus

A series of ferrocene-modified amino acid methyl esters with pyrazole linker was prepared in good to quantitative yields starting from easy accessible ferrocene pyrazole carbaldehyde and amino acids in racemic and enantio enriched forms under reductive amination conditions (NaBH (OAc)₃, reflux, 3 hr). The resulting enantiomers were resolved using analytical HPLC on modified cellulose or amylose as chiral selectors. In vivo electrophysiological experiments were performed in the CA1 field of the hippocampus on 3a Fc-Gly, (L)- 3b Fc-Ala, and (D)- 3b Fc-Ala compounds. An increasing in the amplitudes of responses of local potentials (up to 25%) of the CA1 region in the studied groups was found after intraperitoneal administration of ferrocene compounds 3a and (D)- 3b compared with control rats treated with saline.     

Reactive compatibilization of recycled low density polyethylene/butadiene rubber blends during dynamic vulcanization

For reactive compatibilization of the recycled LDPE with butadiene rubber (BR) an equal quantity of few couples of reactive polyethylene copolymer/reactive polybutadiene (1/1) were introduced into the corresponding phases before the dynamic vulcanization. The LDPE/BR thermoplastic dynamic vulcanizates (TDVs) produced using the poly(ethylene-co-acrylic acid), PE-AA/polybutadiene terminated with isocyanate groups, PB-NCO compatibilizing couple with different ratio of functional groups have demonstrated the best mechanical properties and have been characterized by X-Ray analysis and DMTA measurements. For all of systems studied the increasing components compatibility due to the formation of the essential interface layer have been observed. The PB-NCO modifier participates in two processes: it is co-vulcanised with BR in rubber phase and reacts in the interface with the PE-AA dissolved in LDPE. The amorphous phase of LDPE is dissolved by rubber phase, i.e. the morphology with dual phase continuity is formed that provides an improvement of mechanical characteristics of material obtained. The best combination of mechanical characteristics was obtained for LDPE(PE-AA)/BR(PB-NCO), PB-NCO=7.5 wt.% per PB, COOH/NCO=1/1. The tensile strength and an elongation at break for these blends were 3.9 MPa and 353% and for the basic non-compatibilized blend 3.2 MPa and 217%, relatively.     

Self‐Consistent Integral Equation Theory for Semiflexible Polyelectrolytes in Poor Solvent

Self‐consistent hybrid MC/PRISM method is presented for calculating properties of polyelectrolytes in semidilute and more concentrated regimes in a poor solvent. The static structure and conformational behavior of salt‐free polyelectrolyte solutions composed of semiflexible polyions and monovalent counterions are studied using the approach which combines the traditional Monte‐Carlo (MC) simulation with the numerical solution of the polymer integral PRISM equation. The MC technique is applied to generate the configurations of a single chain molecule and obtain the averaged intrapolymer correlation function. The PRISM equation is then numerically solved for a given monomer density to obtain the various correlation functions and the medium‐induced intrapolymer potential. This is used in a single chain MC simulation, where the polymer sites interact via the bare Coulomb potential together with the short range attractive potential and a self‐consistently determined medium‐induced potential. The monomer‐monomer pair correlation functions and static structure factors are calculated for a large variety of parameters. Conformational properties such as the radius of gyration and visual images are obtained as a function of attractive short‐range interaction, monomer density, Bjerrum length, and chain stiffness. The MC/PRISM study predicts that there is a range of hydrophobicity and monomer density for which polyion chains can form the toroidal structure in a poor solvent. Nonmonotonic dependence of the chain size on monomer density is predicted over the entire range of parameters. Polyion structure factor peak position as a function of density is described. Two concentration regimes in which the polyion structure factors exhibit physically different peaks were found. Over the entire concentration regime considered polyelectrolyte chains undergo strong compression with R_g ∝ lequation/tex2gif-stack-1.gif.

Conformation of a polyion chain for l_B = 2, ε = 0.18 at ρ* = 0.2 and α = 10°.     

Synthesis of aminopyridines from 2-fluoropyridine and lithium amides

Lithium amides promote the amination of 2-fluoropyridine under mild reaction conditions, providing 2-aminopyridines in good yields and purity. Treatment of 2-fluoropyridine with 1 equiv of lithium amide at room temperature affords complete conversion after 2 h. To our knowledge, this is the first study of lithium amide-promoted amination of fluoropyridines that are not further activated by electron-withdrawing groups.     

Influence of peripheral substituents on the stability of sandwich-type complexes of crown ether-containing anthraquinoneimines

Benzo-15-crown-5 ether derivatives of 1-hydroxy-9,10-anthraquinone-9-imine bearing a substituted benzoylamino group, NHCO(p-C₆H₄NO₂) or NHCOC₆F₅, in position 2 were synthesized by a photochemical method. The structure of the fluorine-containing compound was determined by single-crystal X-ray diffraction. Both synthesized dyes, as well as their analogue without substituents on the benzoyl ring, are capable of binding Sr²⁺ and Ba²⁺ to form sandwich-type 2:1 (ligand:metal) complexes. In MeCN, these complexes exhibit higher stability constants (K_2:1) than the corresponding 1:1 complexes (K_1:1). The para-substitution of the benzoyl ring with a nitro group leads to a significant increase in both the K_2:1 constant and the K_2:1/K_1:1 ratio. The fluorination of the benzoyl ring insignificantly affects the stability of sandwich complexes. Density functional theory calculations showed that this is related to steric interactions in the benzoylamino group. The calculated structures of the dyes and their sandwich complexes with Ba²⁺ are consistent with the 2D NOESY data.     

Determination of glutathione in blood via capillary electrophoresis with pH-mediated stacking

A new approach has been developed for the direct determination of reduced (glutathione [GSH]) and oxidized (glutathione disulfide [GSSG]) GSH in whole blood by means of capillary electrophoresis. Its features include GSH-stabilizing sample preparation, the use of an internal standard, and pH-mediated stacking. Blood stabilized with acid citrate and K₃EDTA was treated with acetonitrile with N-ethylmaleimide, and then the analytes were extracted with diethyl ether. The total analysis time was 8 min using a 50-µm (i.d.) by 32.5-cm (eff. length) silica capillary. The background electrolyte was 0.075-M citrate Na pH 5.8 with 200-µM cetyltrimethylammonium bromide and 5-µM sodium dodecyl sulfate, and the separation voltage was −14 kV. The quantification limit (S/N = 15) of the method was 1.5 µM for GSSG. The accuracy levels of GSH and GSSG analysis were 104% and 103%, respectively, and between-run precision levels were 2.6% and 3.2%, respectively. Analysis of blood samples from healthy volunteers (N = 24) showed that the levels of GSH and GSSG and the GSH/GSSG ratio in the whole blood were 1.05 ± 0.14 mM, 3.9 ± 1.25 µM, and 256 ± 94, respectively. Thus, the presented approach can be used in clinical and laboratory practice.     

Diagnostics of properties of capacitor foil with extended nanostructured surface

The results of the study of nanostructured titanium coating used for producing cathode foils of electrolytic capacitors with the best operating characteristics in the world are described. The coating is produced by titanium deposition on an aluminum substrate by electron-beam evaporation in a nitrogen atmosphere. The study was performed using scanning electron microscopy, atomic-force microscopy, X-ray photoelectron spectroscopy, and thermodesorption spectroscopy.     

Interfacing Living Unicellular Algae Cells with Biocompatible Polyelectrolyte‐Stabilised Magnetic Nanoparticles

Green algae are a promising platform for the development of biosensors and bioelectronic devices. Here we report a reliable single‐step technique for the functionalisation of living unicellular green algae Chlorella pyrenoidosa with biocompatible 15 nm superparamagnetic nanoparticles stabilised with poly(allylamine hydrochloride). The magnetised algae cells can be manipulated and immobilised using external permanent magnets. The distribution of the nanoparticles on the cell walls of C. pyrenoidosa was studied by optical and fluorescence microscopy, TEM, SEM and EDX spectroscopy. The viability and the magnetic properties of the magnetised algae are studied in comparison with the native cells. The technique may find a number of potential applications in biotechnology and bioelectronics.

     

Deuterium release from lithium irradiated by deuterium plasma

Lithium targets are exposed to deuterium plasma with a fluence of 10²²–10²³ D/m² and then heated at a rate of about 5°C/s up to 600°C. Intense deuterium release starts at 400°C. Based on the TDS measurements, it is assumed that deuterium in Li exists in two equilibrium phases: a solid solution and LiD precipitates that start to actively decompose above 400°C.