Study of soft X-ray emission from Z-pinches with a complex atomic composition

Results are presented from experimental studies of Z-pinches produced by implosion of aluminum and tungsten cylindrical wire arrays in the Angara-5-1 facility. The electron temperature T _e and density n _e of the high-temperature pinch plasma have been determined by analyzing line emission from multicharged ions. For the same mass and radius of the array and the same number of wires in it, the intensity of line emission of H- and He-like Al ions from an imploded Al + W wire array containing even a small amount of tungsten (7 wt %) is one order of magnitude lower than that from an Al array. As the W content increases, the total soft X-ray (SXR) yield increases, while the duration of the SXR pulse decreases. For the 30% W content in the array, the power and duration of the SXR pulse are nearly the same as those recorded during the implosion of a W array with the same linear mass and radius and the same number of wires. Results are also presented from experiments with nested wire arrays in which the outer and inner shells were made of Al and W wires, respectively. It is found that, in this case, the effect of tungsten on the line emission of aluminum is much weaker than that in experiments with arrays in which tungsten and aluminum wires were placed in the same shell, even if the mass of the inner (tungsten) shell was larger than that of the outer (aluminum) one. At the same time, the inner W shell plays a significant role in the implosion dynamics of a nested wire array, reducing the duration of the SXR pulse and increasing the SXR power.     

Simulations of the Evolution of the Heterophase Electrode of a Vacuum Transmission Line During the Passage of a High Current Pulse

Plasma Physics Reports - In electromagnetic generators of the terawatt range with current pulse of 1–30 MA, electric explosion of the surface of current-carrying electrodes takes place. One...     

Development of a sex-specific molecular marker for Japanese hop Humulus japonicus Siebold & Zucc

Japanese hop (Humulus japonicus Siebold & Zucc.) is a dioecious plant and a suitable model for studying the XX/XY1Y2 system of sex chromosomes. To develop a sex-specific marker, 12 RAPD and 36 ISSR markers were analyzed on the basis of pools of male and female plants identified after flowering. We were the first to identify ISSR marker K-16, which manifested stable amplification of an approximately 300-bp fragment in male plants and the absence of amplification in female plants in the populations examined. Marker effectiveness was confirmed in several Japanese hop populations of different origin.     

Comparative molecular cytogenetic characterization of partial wheat-wheatgrass hybrids

The chromosomal composition of the Zernokormovaya 169, Istra 1, Ostankinskaya, and Otrastayushchaya 38 cultivars of octoploid partial wheat-wheatgrass hybrids was studied using genomic in situ hybridization (GISH). Differentiation of wheatgrass chromosomes by the distribution of the GISH signal along the chromosome was revealed. The wheatgrass chromosomes of the hybrid cultivars studied in the work differed in the type of differentiation, centromeric index, and absolute size. The cytogenetic distinctions of these chromosomes revealed by us can be used in making crosses and in studying the transmission through gametes of additional wheatgrass chromosomes.     

Laser radiation scattering from the wires and fibers of imploding arrays on the Angara-5-1 facility

A method is developed for measurements of laser radiation scattering by wires and fibers in different types of imploding arrays in the initial stage of plasma production at discharge currents per wire of up to 2 kA for aluminum arrays and up to 8 kA for tungsten arrays. The experiments were carried out on the Angara-5-1 facility at a current density in the wires of 10⁸ A/cm² and current growth rate of ～10¹³ A/s. It is found that the indicatrix of laser radiation reflected from the wires (fibers) in cylindrical and conical arrays is modified at currents of 0.1–10 kA per wire (fiber). The experimental data on the reflection and scattering of laser radiation from wires and fibers are compared with the results of numerical simulations of their electric explosion in vacuum. It is proposed that the change in the reflection indicatrix of laser radiation is caused by the onset of thermal instabilities. The typical size of density and temperature inhomogeneities on the wire surface is in a range of 10–20 μm, which probably results in a transition from specular to diffuse reflection of laser radiation. A simultaneous abrupt (over 2–3 ns) reduction in the reflection intensity from several wires of an array indicates a homogeneous distribution of the discharge current over the irradiated wires. This closes the issue of the quality of the contact between the wires and the electrodes. The obtained experimental information is of considerable importance for the development of numerical codes for simulations of the implosion of wire arrays and the refinement of the wire parameters in the initial stage of plasma production.     

Influence of ligands’ peripheral substituents on the structure, magnetochemical and electrochemical behaviour of complexes containing a Cu2O2 butterfly core

New polydentate open structure ligands H₃L1 and H₃L2 were synthesized by the condensation of 2,6-diformyl-4-tert-butylphenol and corresponding N-R-o-phenylenediamines (R = Ac and R = Boc). Treating of the ligands with copper trimethylacetate leads to binuclear copper complexes with dissimilar Cu₂O₂ cores, the structures of which were solved by X-ray diffraction analysis. The electrochemical properties of both complexes were studied; the observed redox transitions were assigned to specific redox-active sites of the molecule. These assignments were confirmed by DFT calculations of the electronic structure of binuclear complexes. Both complexes exhibit antiferromagnetic behaviour, as confirmed by variable-temperature magnetic studies.     

Erythrocyte diagnostic kits for detection of Pseudomonas aeruginosa exotoxin A

The use of formulated chick red blood cells loaded with IgG preparations and affinity-purified antibodies, in comparison with initial immune serum to P. aeruginosa exotoxin A (ETA), has been shown to increase the sensitivity of antibody erythrocyte diagnosticum (AbED) 17-fold and to ensure the detection of ETA at a concentration of 1.2 mg of protein per ml. The passive hemagglutination (PHA) test with AbED has proved to be a more sensitive method for the detection of ETA than the antibody neutralization test with the use of antigenic erythrocyte diagnosticum, the latex agglutination test, the coagglutination test and the enzyme immunoassay. The PHA test has permitted the detection of ETA in the culture fluid of 80% of P. aeruginosa cultures under study.