Mass Spectrometric Analysis of Microcystins from Cyanobacterial Biomass: Optimization of the Sample Preparation Procedure

The sample preparation procedure for determination of microcystins from biomass by the LC–MS method was optimized. Treatment of freeze-dried biomass samples with acetonitrile prior to the main extraction was effectively used for decreasing the amount of protein-like matrix compounds in extracts. Use of acetonitrile–water mixtures during the main ultrasound-assisted extraction allowed increasing the total microcystins amount in the resultant extracts compared to the traditional extraction using 75% methanol.     

Structure and sorption characteristics of bioaffinity membranes

The new bioaffinity membranes comprise mammalian blood and tissue cells immobilized in the polymer matrix. The method of immobilization does not assume the retention of physiological and enzymatic activity of immobilized cells, but it ensures the safety of cellular membrane receptors that are used as specific ligands. Macroporous polymer carriers based on polyacrylonitrile maintain the accessibility of the cellular receptors for all blood plasma components including immunoglobulins and viral particles. The sorption capacity of membranes with respect to model substances in a batchwise technique is evaluated. Although the results are of a preliminary nature, the membranes may be used in crossflow modules for selective blood plasma correction of endogenous substances.     

Parametric and high-frequency instability of Alfvén and magnetoacoustic waves in a plane waveguide run through by an ionized gas flow with a transverse magnetic field

We study the parametric and high-frequency instability of Alfvén waves and magnetic sound in a plane waveguide run through by a plasma flow. The mode energies and synchronism conditions are described and the possibility of efficient spectral up-conversion of Alfvén modes and magnetic sound is shown. State Technical University, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 4, pp. 469–474, April, 1998.     

Angular distributions in proton-nucleus interactions in emulsion at 800 GeV

Data on angular distributions of heavily ionizing and shower particles in incoherent protonnucleus collisions in emulsion at 800 GeV are reported and discussed in details. Dependence of angular distributions on the mass number of a target nucleus and on the multiplicity of charged particles is investigated. The data presented are systematically compared with results of emulsion experiments at lower energies and with predictions of the Lund Monte Carlo model FRITIOF.     

Generation of the second harmonic of an alfvén wave as a result of development of an explosive instability in a flow-plasma system

We study the possibility of up-conversion and explosive instability in the system flow-magnetoactive plasma. The synchronism conditions and mode energies are found and the shortened equations for the slowly varying mode amplitudes are obtained. It is shown that the “explosion” is stabilized due to generation of weakly decaying harmonics of an Alfvén wave. State Technical University, Nizhny Novgorod, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 41, No. 8, pp. 985–990, August, 1998.     

Interpenetrating polymer networks based on diisocyanates and polar monomers

Compatible interpenetrating polymer networks systems (IPS) have been obtained by two-stage polymerization of a mixture of diisocyanates (M₁) with various different polar monomers (M₂) initiated by catalytic systems based on tertiary amines. In the first stage, a polyisocyanate network (P₁) is formed and then M₂ is polymerized on a regenerated active centre with the formation of a linear polymer (L₂) specially arranged in P₁. The essential features of the formation of IPS of this type are considered. Some physico-mechanical and thermal characteristics are reported.     

Morphological Stability of the Solid–Liquid Interface during Melt Crystallization of Ca1–xSrxF2 Solid Solution

Crystallography Reports - Proceeding from the phase diagram of the CaF2–SrF2 system, the stability of crystal–melt interface of solid solution against constitutional supercooling has...