Distribution of matter in the current-carrying plasma and dense core of the discharge channel formed upon electrical wire explosion

Distribution of matter in the discharge channel formed upon a nanosecond electrical explosion of a single wire in air and vacuum was studied experimentally. Simultaneous use of optical, UV, and X-ray diagnostics made it possible to distinguish qualitatively different regions of the discharge channel, such as the current-carrying layers and the region occupied by a weakly conducting cold plasma. Several series of experiments with 25-μm-diameter 12-mm-long wires made of different materials were performed. The charging voltage and the current amplitude were varied in the ranges of U ₀ = 10–20 kV and I _max ∼ 5–10 kA, respectively. Explosion regimes with a current pause and with and without current interruption, as well as with wire preheating in air and vacuum, were studied. Shadow and schlieren images of the discharge channel were obtained using optical probing at the second harmonic of a YAG: Nd⁺³ laser (λ = 0.532 μm, τ ∼ 10 ns). In the experiments carried out in vacuum, X-ray images of the discharge channel were also obtained using an X-pinch as a point source of probing radiation and UV images were recorded using a four-frame MCP camera.     

Why Doesn't the Creed Read "Always Be Critical"? An Examination of a Liberal Curriculum

Using ethnographic data collected in a second grade classroom over the course of a school year, this paper describes the ways in which one school's discourse of liberalism is deleteriously deployed. We view the school's discipline creed as emblematic of the school's liberal curriculum, and interrogate the effects on four African American boys in the classroom when the school enacts this creed. Despite the agency that these boys obviously had, they were unable to control the ways in which they were placed at a structural disadvantage and manipulated by a system far more powerful than they were. The results were that these four boys suffered. Not only did the intended liberal curriculum fail to be translated fully into the enacted curriculum, the liberal underpinnings of this curriculum precluded teachers and students from taking any critical stance.     

Mobilization of phase I plasmid in Shigella sonnei and stability of its inheritance in rough strains of Shigella and Escherichia

The plasmid pSS120, determining the synthesis of species specific I phase antigen of Shigella sonnei is mobilized for genetic transfer into E. coli K12 recipient cells with the frequency 12-41%. The frequency depends on the type of mobilized plasmid and recipient strain. The I phase antigen is normally expressed in II phase recipient cells and in E. coli cells. During mobilization pSS120 forms cointegrates representing a recombinant of mobilizing and mobilized plasmids DNA. The study of pSS120 inheritance stability has shown the plasmid to be unstable during culturing of bacteria and to be partially lost from the parent Shigella sonnei strains as well as from the "hybrid" transconjugants obtained. The 60 Md plasmid present in the donor strains of Shigella sonnei is prone to structural fragmentation particularly expressed in Shigella sonnei/E. coli hybrids.     

Use of a protoplasting method for altering the qualitative and quantitative composition of the anthracycline complex in Streptomyces peucetius var. caesius

Conditions for efficient regeneration in mutant strains of the doxorubicin-producing organism Str. peucetius var. caesius were developed. The effect of the protoplast regeneration on changes in the proportion of the components of the anthracycline complex produced by these strains was shown. Variants with doxorubicin productivity 2 times higher than that of the parent strain were isolated.     

Autocatalytic nature of "slow virus infections"

A concept that considers the causative nature of the so-called "slow virus infections", causing syndromes of spongiform encephalopathies in man and animals as a chain autocatalytic process is put forward. According to this concept, PrP(27-30) protein, isolated recently from the brains of scrapie-infected animals, is a C-terminal domain of the normal protein component of brain tissue which is a latent zimogen. Certain clinical and experimental data are discussed within the framework of this concept. Exogenous proteinases are presumed to be capable of triggering such a chain autocatalytic process in the brains of susceptible animals. Indeed, in one of our experiments, a subtoxic dose of pronase injected into mouse brain induced the development of a syndrome indistinguishable from spongiform encephalopathy in its clinical and pathomorphological manifestations. The probable role of neuron-specific proteins of intermediate filaments in such pathological processes is discussed. It seems possible that spongiform encephalopathies are particular cases of pathological processes that have catalytic nature. Presumably, the Alzheimer disease has such a catalytic causative nature.     

Modification of the process of resorption of alpha-emitting nuclides from the gastrointestinal tract depending upon the properties of administered compounds and the physiological state of rats

In experiments on rats a study was made of resorption from the gastrointestinal tract of simple salts, complex compounds and "biologically incorporated" forms of transuranium nuclides, the influence of age, pregnancy and chemically active substances (for instance, trivalent iron and ethyl alcohol) on this process.