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This article describes the experimental and theoretical studies of the mechanisms of failure of ABS polymer in the range of strain rates of 10–4–103 s–1 at different temperatures of testing (from an ambient temperature of 23 to 100°C). The alteration of the type of failure as a function of the strain rate and temperature is analyzed. Based on the structure–time approach, a model of the temperature–rate superposition is proposed.

Experimental and theoretical data for the strength performance of 1230 aluminum alloy under tension in the quasi-static and dynamic ranges of loading parameters are presented. Using the structural temporal approach and the sign-perturbed sums algorithm, the feasibility of raising the strain rate of a specimen by decreasing its geometrical size has been estimated.

The mechanical properties of the additive material prepared from acrylonitrile–butadiene–styrene plastic are studied experimentally on a 3D printer in the quasi-static and dynamic regimes. The strength curve describing the nonlinear dependence of the critical stress on the strain rate is constructed using the incubation time. The characteristic incubation time τ is determined by comparing the theoretical curve with the experimental data.

Dynamics and spectral transmission of Al plasma produced by extreme ultraviolet (EUV) irradiation of 0.75-μm thick Al foil is investigated. The EUV radiation with the peak power density in the range of 0.19–0.54 TW/cm2 is provided by Z-pinch formed by W multiwire array implosion in the Angara-5-1 facility. Geometry of the experiment ensures that there are no plasma fluxes from the pinch toward the Al foil and plasma. The same EUV source is used as a back illuminator for obtaining the absorption spectrum of Al plasma in the wavelength range of 5–24 nm. It comprises absorption lines of ions Al4+, Al5+, Al6+, Al7+. Analysis of relative intensities of the lines shows that those ions are formed in dense Al plasma with a temperature of ∼20 eV. Dynamics of Al plasma has been investigated with transverse laser probing. We have also performed radiation-gas-dynamics simulations of plasma dynamics affected by external radiation, which includes self-consistent radiation transport in a plasma shell. The simulations show good agreement with an experimental absorption spectrum and with experimental data concerning plasma dynamics, as well as with the analysis of line absorption spectrum. This confirms the correctness of the physical model underlying these simulations.

The effect of induced transparency of thin Al foils radiatively heated by intense extreme ultraviolet (EVU) radiation has been observed. The radiation of the plasma of Z-pinches appearing under the compression of tungsten liners at the Angara-5-1 facility has been used as the radiation that heats the Al foil (peak illumination on the foil ~0.55 TW/cm2) and is transmitted through it. The photoabsorption has been studied in the formed aluminum plasma at temperatures of ~10–30 eV in the density range of ~1–20 mg/cm3 in the wavelength range of ~5–24 nm. Absorption lines of Al4+...7+ ions have been identified in the experimental spectrum. In addition, radiative gas-dynamic simulations of the foil heating and expansion have been performed taking into account radiation transfer processes.

Results are presented from experimental studies of the spatial distribution of the density of matter in the central part of the discharge gap and the formation of the temporal profile of the X-ray power in the course of implosion of quasi-spherical wire arrays at discharge currents of up to 4 MA. The spatial distribution of the X-ray intensity in the central part of the discharge gap and the temporal profile of the X-ray power are used as implosion characteristics of quasi-spherical wire arrays. The quasi-spherical arrays were formed by the radial stretching of unstrained wires of initially cylindrical and conical wire arrays under the action of the electrostatic field. The temporal profile of the output X-ray pulse in the photon energy range of 0.1–1 keV is shown to depend on both the geometrical parameters of the quasi-spherical array and the longitudinal distribution of its mass. It is found that a 40% increase in the wire mass due to deposition of an additional mass in the equatorial region of a quasi-spherical array leads to a 15% increase in the average current radius of the pinch and a 30% decrease in the X-ray yield. Experiments with quasi-spherical arrays made of kapron fibers with deposited Al and Bi conducting layers were also carried out. It is demonstrated that application of such arrays makes it possible to control the profile and duration of the generated X-ray pulse by varying the mass, material, and location of the deposited layer. It is found that deposition of an additional mass in the form of a thin Bi stripe on tungsten wires near the cathode end of the array allows one to mitigate the influence of the cathode zipper effect on the pinch compression and formation of the X-ray pulse in tungsten arrays.

Phospholipases A2 (PlA2) are the most common compounds of snake venom. Ability of the enzyme to affect cell interactions, particularly platelet aggregation, proliferation of cancer cells, processes of angiogenesis and cell differentiation, potentiates it as a therapeutic or cancerostatic agent in treatment of malignant tumors. Indicated potential medicinal functions of PLA2 require high purified protein. We developed and probated method for phospholipase A2 obtaining from venom of snake Gloydius blomhoffii brevicaudus. The technology consists of four consecutive stages of chromatographic separation. Purified PLA2 is acidic protein with molecular weight of 13762.86 Dа and рІ 4.17. Estimated optimal pH for the enzyme constitutes 8.5. PLA2 inhibits ADP-induced platelet aggregation and exerts cytotoxic effect. Its ability to induce differentiation of РС12 cells, declared by other authors, was not shown.

Gloydius venom is a rich natural source of proteins possessing platelet aggregation inhibition activity. These proteins or their recombinant analogs are universal instruments for the investigation of proteins and receptors interaction in hemostatic system. At the same time previously studied and potentially new pharmacological properties of platelet aggregation inhibitors from snake venoms create a background for the development of the manufacturing technologies. This study presents a part of technological development of several target proteins parallel obtaining from G. blomhoffii brevicaudus snake venom, in particular deve­lop­ment of manufacturing steps for platelet aggregation inhibitor.The target protein was purified using three different chromatographic approaches. It was shown that it is a single chain protein with molecular weight 12001.55 Da, isoelectrical point 8.03, which inhibited platelet aggregation in the rabbit platelet rich plasma with ID50 = 3.26×10-6 g or 542×10-9 М and revealing no enzyme activity.

The results of a study of a radiating Z-pinch with a profiled initial gas-density distribution over the z axis are presented. The gas distribution with the density maximum and transverse-size minimum at the discharge-gap center is formed by a pulsed gas valve with a specially designed nozzle. The parameters of X-ray radiation are measured for pinches formed in gaseous neon at currents of up to 200 kA. The experimentally selected gas density ensures the formation of a region with a typical size of less than 1 mm at the discharge-gap center. This region emits X-ray radiation in the keV photon-energy range in a time of less than 5 ns. Prospects for the development of an X-ray source based on this mechanism are discussed.

The process of Z-pinch decay upon current termination is considered. The experimental data obtained for the Angara-5-1 facility on compression of multiwire tungsten liners are discussed. It is shown that among the decay products there are microparticles of the eroded liner construction material and plasma fluxes. It was determined that the plasma flow velocities exceeded the ‘thermal’ velocities of the Z-pinch plasma. A model for the description of the process of ion acceleration based on an ambipolar mechanism is suggested. Precautions for protection of the peripheral equipment against the decay products of Z-pinch are discussed and protective components are studied. A fast electromagnetic shutter is used for protection from microparticles.

In SRC RF TRINITI investigated implosion of cylindrical and quasi-spherical wire arrays. Such arrays are made of metal wires and plastic fibers both coated by metal. For three-dimensional quasi-spherical arrays implosion the technique was developed to produce wires or fiber with a given distribution of linear mass along the wires. That mass distribution needs for good implosion to the center of array. The wires and fibers was formed by spraying a metal on wire or fiber. We have also developed the technique of manufacture of only tungsten wire with a given distribution of mass per unit length.

Investigation of the influence of divalent metal cations on the induction of plasminogen catalytic activity by monoclonal antibody IV-Ic showed that the presence of metal cations in the reaction medium changes the induction by slowing down or accelerating the process. Ions of Zn(2+), Mn(2+), and Cu(2+) completely inhibit activation. Ions of Co(2+) and Ni(2+) decrease the rate of the first and second phases of the reaction more than 2 times. Ca(2+) ions do not have any effect on the activation rate. Ions of Mg(2+), Ba(2+), and Sr(2+) increase the rate of the first phase of the reaction by 1.5, 2.0, and 2.0 times and the rate of the second phase by 2.0, 3.8, and 4.7 times, correspondingly. Sr(2+) ions have the strongest stimulating effect on plasminogen activation by monoclonal antibody IV-Ic. Investigation of the dose dependent effect of Sr(2+) on the rate of plasminogen activation by monoclonal antibody IV-Ic showed stimulating effect of Sr(2+) at concentrations from 0.1 to 1.0 mM with half maximum at 0.6 mM. However, Sr(2+) ions do not affect amidolytic activity of plasmin and activation of plasminogen by streptokinase. Sr(2+) ions also do not affect monoclonal antibody IV-Ic binding to plasminogen. The effect of Sr(2+) is specific and mediated by the IV-Ic component. The presence of metal cations affects conformational changes in the process of active site formation. Metal cations also affect structure of the plasminogen molecule active site in the complex with monoclonal antibody IV-Ic and enzyme-substrate interaction. The effect of alpha(2)-antiplasmin on the induction of plasminogen catalytic activity by monoclonal antibody IV-Ic in range of concentrations from 5 to 30 nM has been studied. alpha(2)-Antiplasmin at concentration 30 nM almost completely inhibits induction of plasminogen catalytic activity by monoclonal antibody IV-Ic at the ratio plasminogen/alpha(2)-antiplasmin of 3 : 1. This can be explained by competition of alpha(2)-antiplasmin and monoclonal antibody IV-Ic for the lysine-binding sites of plasminogen and inhibition of the active center in activated complex plasminogen*-mAB IV-Ic. Divalent metal cations and alpha(2)-antiplasmin are important factors in induction of plasminogen catalytic activity by monoclonal antibody IV-Ic.

The set of diagnostic techniques used at the Angara-5-1 facility that make it possible to study the processes which accompany the ultrafast current-driven implosion of liners is described. This set includes electric methods and methods for the detection of various radiations. The liner-plasma shapes are visualized by detecting the intrinsic liner radiation in various wavelength ranges and actively probing liners in the visible and X-ray regions. Examples of the results of studying the current-driven implosion of cylindrical arrays of tungsten wires at the Angara-5-1 facility are presented.

The features are studied of plasma production in the initial stage of implosion of hollow cylindrical wire arrays at electric-field growth rates of 1012 V/(cm s). The results are presented from the analysis of both UV emission from the wire plasma and the discharge parameters in the initial stage of the formation of a Z-pinch discharge. It is found that, a few nanoseconds after applying voltage to a tungsten wire array, a plasma shell arises on the wire surface and the array becomes a heterogeneous system consisting of metal wire cores and a plasma surrounding each wire (a plasma corona). As a result, the current switches from the wires to the plasma. A further heating and ionization of the wire material are due primarily to heat transfer from the plasma corona. A model describing the primary breakdown along the wires is created with allowance for the presence of low-Z impurities on the wire surface.

The results of spectral measurements of radiation from microsecond gas Z-pinch are presented. The pinch current is 250 kA with a rise time of 1 μs. At the maximum nitrogen-pinch compression, the radiation spectrum corresponds to the emission of helium-, lithium-, and beryllium-like ions. The spectral-intensity peak lies within the spectral range 15–25 nm, which corresponds to the 2s-3p transitions of Li-and Be-like ions and to higher-energy transitions of these ionization states (2s-4p, 2s-5p, and 2s-6p). The spectra are measured in the first, second, and third diffraction orders. The total yield of X rays measured by a thermocouple-based calorimeter was 45 J at a 2-kJ electric energy stored in the capacitor bank. The pinch-radiation intensity and the spectra obtained experimentally are compared to the results of two-dimensional simulation of the emitting-plasma plasma dynamics using the ZETA radiation-magnetic hydrodynamic code.

It was shown by the methods of induced electron emission that a transfer of the electron density from C60 molecules to the eight-membered ring of sulfur is characteristic of C60·2S8. The value of the (σ+π)-plasmon energy for C60·2S8 is approximately 1 eV less than that for pure C60. In a high vacuum, the C60·28 surface is depleted in sulfur.

Enaminones are applied as synthons in the preparation of heterocyclic compounds [1, 2]. Their properties depend essentially on the character of the amine fragment of the molecule. In this study we showed that the enaminones obtained from acetylacetone and monosubstituted 1,2-ethylenediamines at 200–250°С suffer a thermal cleavage to give acetone and N-substituted imidazolines. The reaction apparently proceeds along a mechanism similar to that of the ester cleavage of β-dicarbonyl compounds.

A number of compounds possessing a 2-oxoimidazolidine ring exhibit different kinds of biological activity. Examples are biotin (vitamin H) [1], marine sponge alkaloids [2], isocarbamide (N-isobutyl-2-oxoimidazolidine-1-carboxamide, herbicide) [3]. Biological activity is also inherent to many vinyl ethers derived from amino alcohols [4]. With a view to extent the series of potential biologically active compounds we synthesized previously unknown vinyloxy derivatives of N-(2-hydroxypropyl)-1,3-imidazolidin-2-one. Reactions of vinyl ethers Ia and Ib with 3 equiv of ethylenediamine at 50°C gave N-[vinyloxy(hydroxy)alkyl]ethene-1,2-diamines IIa and IIb which were subjected to condensation with urea at 175–180°C to obtain the corresponding substituted imidazolidin-2ones IIIa and IIIb in almost quantitative yield.

Fluorination and nitration of bis(2,2,2-trinitroethyl)urea has given the novel N-fluoro-bis(2,2,2-trinitroethyl)urea and N-nitro-bis(2,2,2-trinitroethyl)urea. The thermal decomposition rates and parameters for bis(2,2,2-trinitroethyl)urea and its derivatives have been found, and the standard enthalpies of combustion, and the standard enthalpies of formation of these compounds calculated therefrom, have been determined.

This review summarizes current data suggesting that A-chain of the human alpha-thrombin molecule plays a role of allosteric effector in catalytic reactions with various substrates. Special attention is paid to the relationship between A-chain structure and catalytic activity of thrombin. The existence of this relationship is based on studies of natural mutation of A-chain of the alpha-thrombin molecule. Use of molecular and essential dynamics confirmed the role of A-chain in changes of conformation and catalytic properties of this enzyme; these changes involve residues located in the specificity sites and some inserting loops. Current knowledge on structure and properties of thrombin can be used for the development of new antithrombin agents.

Summary form given only. Complex of techniques for research superfast implosion of liners on installation Angara-5-1 includes electrotechnical methods, methods of registration of various radiations and active probing. Electrotechnical methods allow to evaluate the deposited in the liner power and energy, inductance of the liner. Use of microprobes allows to estimate distribution of density of a current inside the liner and the rate of plasma production. Visualization of the form of plasma of liners is carried out by registration of own radiation of liners in various ranges and active probing in visible and x-ray ranges. It allows to estimate distribution of density of substance inside the liner, distribution of brightness of various areas of the liner. Examples of the results of studying the current-driven implosion of cylindrical arrays of tungsten wires at the Angara-5-1 facility are presented.

Several indirect plasminogen (Pg) activators are known including streptokinase and the monoclonal antibody IV-Ic, whose mechanism of activation is well studied. To characterize thermodynamically the activation of Pg by streptokinase (SK) and the monoclonal antibody (mAB) IV-Ic, the activation energies were calculated for various reaction stages. Activation energy of 7.4 kcal/mol was determined for the interaction of the chromogenic substrate S-2251 with plasmin (Pm) and activated equimolar complexes Pm—SK and Pg*SK at the steady-state reaction stage, and 18.7 kcal/mol with the complexes Pg*IV-Ic. A 2.5-fold increase in the energy of activation for the Pg*IV-Ic complex suggests a more intricate mechanism of its interaction with the substrate. At the stage of increasing active center concentrations and the formation of activated complexes Pg*SK and Pg*mAB IV-Ic, the activation energy was found to be 10.5 and 38 kcal/mol, respectively. At this reaction stage the conformational rearrangement of Pg molecule with the formation of active center is the limiting stage determining the reaction rate. Unexpectedly high energy of activation at the second stage of interaction between mAB IV-Ic and Pg suggests several simultaneous reactions and complexity of conformation rearrangement in the Pg molecule in activated complexes, thus requiring large energy expense. Formation of the active center is probably accompanied by its transition within a narrow temperature range into another conformation state with the change in activation parameters of the reaction. Quantitative evaluation of the studied reactions from the perspective of thermodynamics of the enzymatic reactions gives more comprehensive characteristics of the activation mechanism.

Sorbents containing 10–12 % fullerene C60 were prepared by the reaction of C60 with γ-aminopropylsilica gel. C60-Silica gel possesses good chromatographic properties for the separation of aromatic, nitro, and heterocyclic compounds in the regimes of normal and reversed-phase HPLC.

Z pinches and tungsten wire arrays, compressing under action of current, are widely studied in ICF nowadays1,2,3. The wires have typical diameter 5–10 microns. Duration of output soft x-ray emission about 5–10ns. Spatial distribution of mass inside current — driven array during implosion has crucial importance for process of array implosion.

Enaminones are applied as synthons in the preparation of heterocyclic compounds [1, 2]. Their properties depend essentially on the character of the amine fragment of the molecule. In this study we showed that the enaminones obtained from acetylacetone and monosubstituted 1,2-ethylenediamines at 200–250°С suffer a thermal cleavage to give acetone and N-substituted imidazolines. The reaction apparently proceeds along a mechanism similar to that of the ester cleavage of β-dicarbonyl compounds.

A number of compounds possessing a 2-oxoimidazolidine ring exhibit different kinds of biological activity. Examples are biotin (vitamin H) [1], marine sponge alkaloids [2], isocarbamide (N-isobutyl-2-oxoimidazolidine-1-carboxamide, herbicide) [3]. Biological activity is also inherent to many vinyl ethers derived from amino alcohols [4]. With a view to extent the series of potential biologically active compounds we synthesized previously unknown vinyloxy derivatives of N-(2-hydroxypropyl)-1,3-imidazolidin-2-one. Reactions of vinyl ethers Ia and Ib with 3 equiv of ethylenediamine at 50°C gave N-[vinyloxy(hydroxy)alkyl]ethene-1,2-diamines IIa and IIb which were subjected to condensation with urea at 175–180°C to obtain the corresponding substituted imidazolidin-2ones IIIa and IIIb in almost quantitative yield.

Problems related to the anisotropy of chemical reactivity in graphite are examined. Possible reasons are indicated for disagreement between experimental values for the anisotropy of the reactivity of graphite toward oxidizing agents and the theoretical anisotropy in the chemical reactivity of the peripheral and internal carbon atoms of the graphite crystal lattice.

The features of interaction between synthetic graphites and oxidizing agents are examined, with a method proposed for separating the effect of physical and chemical factors. Experimental data are presented on the differentiated determination of graphite mass-loss rate on oxidation with the oxygen in the air.