Study of X-ray and neutron emission in experiments with Al wires in an MA plasma focus

Results are presented from experimental studies of the correlation between X-ray and neutron emissions generated in the implosion of a deuteron plasma shell onto an Al wire. The experiments were carried out on the PF-1000 facility at currents of 1.5–1.8 MA. An Al wire 80 μm in diameter and 7–9 cm in length was placed at the end of the inner electrode. During the implosion of the plasma shell, Al K-shell X-rays were first emitted at the dip of the current derivative. After the X-ray pulse, a relatively stable corona with a diameter of 2–3 mm and lifetime of a few hundred nanoseconds formed around the wire. The presence of the wire did not considerably reduce the total neutron yield (at most 10¹¹ neutrons per shot) in comparison to discharges without a wire. As a rule, the intensity of neutron emission was maximal a few tens of nanoseconds after the peak of X-ray emission. A detailed comparison of two shots with low and high neutron yields have shown that the neutron yield depends on the configuration and dynamics of the discharge. The possible influence of the self-generated axial component of the magnetic field on the development of the plasma focus and the acceleration of fast deuterons is discussed.     

Bacterial Genomic Islands: Organization,Function, and Evolutionary Role

Data on the structural organization and evolutionary role of specific bacterial DNA regions known as genomic islands are reviewed. Emphasis is placed on the most extensively studied genomic islands, pathogenicity islands (PAIs), which are present in the chromosome of Gram-negative and Gram-positive pathogenic bacteria and absent from related nonpathogenic strains. PAIs are long DNA regions that harbor virulence genes and often differ in GC content from the remainder of the bacterial genome. Many PAI occur in the tRNA gene loci, which provide a convenient target for foreign gene insertion. Some PAI are highly homologous to each other and contain sequences similar to ISs, phage att sites, and plasmid ori sites, along with functional or defective integrase and transposase genes, suggesting horizontal transfer of PAI among bacteria.     

Analysis of Gliadin Polymorphism in aTriticum speltaL. Collection

Using gliadins, endorperm storage proteins of kernels, as markers, the genetic diversity of 170 samples from the Triticum speltaL. collection of the Vavilov Institute of Plant Industry was studied. High intraspecific polymorphism of the gliadin electrophoretic patterns was revealed. On the basis of similarity of the gliadin electrophoretic patterns, groups of samples were isolated, and the genetic stucturization of the collection was performed.     

Spontaneous frequency of micronuclei in peripheral blood lymphocytes of Kiev residents]

The level of micronuclei in the peripheral blood lymphocytes of Kyiv residents and its dependence on age, sex and smoking status were studied. Analysis of lymphocytes of 102 healthy Kyiv residents showed that the spontaneous frequency of micronuclei in individuals at the age of 21 to 67 (mean age of 42.6) was 10.5 +/- 0.5@1000. The frequency of micronuclei depends on individual age and increases by 3% per year, and also depends on smoking habits (the micronucleus frequency in smokers was 1.3 times higher then nonsmokers). There is no dependence of the micronucleus frequency on the sex of persons.     

Immunochemical properties of erythrocyte-specific histone H5 in salmonid fishes

Comparative studies have been made on the immunochemical properties of histone H5 in Salmonidae species. High degree of homology between these histones and H5 histone from Oncorhynchus tschawytscha was demonstrated by microcomplement fixation. Properties of H5 histones in fish and birds are discussed.     

The influence of post-treatment storage on the frequency of ethyleneimine-induced chromosomal aberrations and gene mutations in barley

Summary Dry seeds of spring barley variety MOS-121 were treated with ethyleneimine and after the treatment were stored in the desiccator over granulated KOH from 6 to 46 days. During this period statistically significant changes in the general level of chromosome rearrangements, number of chlorophyll mutations, death-rate and fertility of M 1-plants were observed. The spectrum of chlorophyll mutations also changed. The maximum genetic effect resulting from storage was noted by the 18th day, and this was followed by the decrease of injuries reached zero by the 46th day.The mode of changes in dynamics of the formation of chromosome aberrations, chlorophyll mutations and recessive lethal mutations proves the similar nature of the initial mechanisms of their potential changes.     

Effect of colchicine and pilocarpine on the secretory activity of rat type II alveolar cells: an ultrastructural study

Colchicine in a total dose of 0.6 mg/100 g body weight per day was shown to reduce the level of apical surfactant secretion by type II alveolar cells in random-bred male albino rats, thereby demonstrating that the cytoplasmic microtubules participate in the release of surfactant into the alveolar lumen. In addition, basal secretion of surface-active material was found in 51% of all the cells. In a single dose of 8 mg/100 g b.w., pilocarpine stimulated apical surfactant secretion. If injected after colchicine, it slightly increased the number of type II alveolar cells ready to release surfactant, but actual secretion was not observed; the level of basal secretion did not increase. It has been suggested that microtubular function is not completely responsible for basal secretion and is only partly responsible for apical surfactant secretion.