Adsorption of Cu(II), Cd(II), Pb(II), Cr(VI) by double hydroxides on the basis of Al oxide and Zr, Sn, and Ti oxides

It was studied the equilibrium adsorption and adsorption kinetics of Cu(II), Cd(II), Pb(II), and Cr(VI) by composite hydroxides formed by Me _x O _y · nH₂O and Me_0.4–0.7Al_0.6–0.3O _y · nH₂O, where Me = Zr, Sn and Ti. It was estimated the values of the diffusion coefficients of adsorbed ions Cu(II) and Cr(VI) from kinetic values. It was established that the estimated diffusion coefficients of adsorbed ions Cu(II) are in the range 0.4 × 10⁻¹²–2.5 × 10⁻¹² m²/s for individual hydroxides and 1.2 × 10⁻¹²–2.8 × 10⁻¹² m²/s for double hydroxides. The obtained values of diffusion coefficients Cr (VI) for double hydroxides are 0.1 × 10⁻¹⁰–0.4 × 10⁻¹⁰ m²/s.     

Adsorption of amyloid beta (1-40) peptide to phosphatidylethanolamine monolayers.

The aggregation of soluble, nontoxic amyloid beta (Abeta) peptide to beta-sheet containing fibrils is assumed to be a major step in the development of Alzheimer's disease. Interactions of Abeta with neuronal membranes could play a key role in the pathogenesis of the disease. Herein, we study the adsorption of synthetic Abeta peptide to DPPE and DMPE monolayers (dipalmitoyl- and dimyristoylphosphatidylethanolamine). Both lipids exhibit a condensed monolayer state at 20 degrees C and form a similar lattice. However, at low packing densities (at large area per molecule), the length of the acyl chains determines the phase behavior, therefore DPPE is fully condensed whereas DMPE exhibits a liquid-expanded state with a phase transition at approximately 5-6 mNm(-1). Adsorption of Abeta to DPPE and DMPE monolayers at low surface pressure leads to an increase of the surface pressure to approximately 17 mNm(-1). The same was observed during adsorption of the peptide to a pure air-water interface. Grazing incidence X-ray diffraction (GIXD) experiments show no influence of Abeta on the lipid structure. The adsorption kinetics of Abeta to a DMPE monolayer followed by IRRAS (infrared reflection absorption spectroscopy) reveals the phase transition of DMPE molecules from liquid-expanded to condensed states at the same surface pressure as for DMPE on pure water. These facts indicate no specific interactions of the peptide with either lipid. In addition, no adsorption or penetration of the peptide into the lipid monolayers was observed at surface pressures above 30 mNm(-1). IRRAS allows the measurement of the conformation and orientation of the peptide adsorbed to the air-water interface and to a lipid monolayer. In both cases, with lipids at surface pressures below 20 mNm(-1) and at the air-water interface, adsorbed Abeta has a beta-sheet conformation and these beta-sheets are oriented parallel to the interface.     

The Effect of Electrochemical and Gas Phase Activation of High Surface Area Carbon Black Ketjen Black EC 600 DJ on Its Surface Composition,Electrochemical Capacitance,and Stability

The effect of electrochemical and gas-phase activation of high-surface-area carbon black Ketjen Black EC 600 DJ on its stability and electrochemical capacitance is studied. The electrochemical activation is carried out according to the “start–stop” protocol (1–1.5 V, 0.5 V/s). The stability of samples is assessed based on variation of their effective resistance (based on the results of cyclic voltammetry (CVA)) and electrochemical capacitance (based on CVA and galvanostatic data) with the cycle number. The changes in the texture and surface properties of activated samples are studied by the methods of nitrogen low-temperature adsorption and X-ray photoelectron spectroscopy. The gas-phase activation of high-surface-area carbon black Ketjen Black EС 600 DJ is shown to impair its stability, while the electrochemical oxidation of carbonblack samples leads to a considerable (two-fold) increase in their electrochemical capacitance.     

Behavior of Na and K in the extraction process of lithium isotope separation

Russian Chemical Bulletin - The extraction behavior of Na and K during lithium isotope separation using benzo-15-crown-5 (B15C5) in chloroform as the extractant was investigated. It was found that...     

Steady waves in a stratified flow over a combined obstacle

A problem of steady internal waves in subcritical flows of a stratified liquid over a finite sequence of bottom elevations is considered. An asymptotic solution of the second order of accuracy, which takes into account nonlinear effects, is constructed by the method of perturbations in terms of the small parameter of the obstacle height. Near-field interference wave structures are studied.     

Existence and Dimension Properties of a Global <Emphasis Type="Italic">B</Emphasis>-Pullback Attractor for a Cocycle Generated by a Discrete Control System

We consider cocycles on finite-dimensional manifolds generated by discrete-time control systems. Frequency conditions for the existence of a global B-pullback attractor for such cocycles considered over a general base system on a metric space are given. Upper bounds for the Hausdorff dimension of the global B-pullback attractor of a discrete cocycle are obtained using the transfer function of the linear part of the cocycle and the discrete Kalman–Yakubovich–Popov frequency theorem.     

The effect of laminins on chemoresistance of colorectal cancer cells

Russian Chemical Bulletin - Earlier, the data on the ability of laminin-332 to protect liver cancer cells from apoptosis caused by doxorubicin, sorafenib, and gefitinib have been obtained. In order...     

Concentration of cesium and francium by distribution and adsorption chromatography

Methods were developed for concentrating cesium and francium from nuclear reaction products using distribution and adsorption chromatography. The feasibility of obtaining concentrated solutions of cesium and francium, both on carriers and carrier-free, has been demonstrated.