Use of non-radioactive biotin-labelled probes for detecting hepatitis A virus]

The biotin-labeled DNA probes were constructed on the basis of the hybrid bacteriophage M13nip 9 single-stranded DNA containing the fragments of the hepatitis A viral cDNA. The probes were biotin treated by chemical modification of the DNA by the peraminating reagent or photochemically. The labeled DNA probes were used in molecular hybridization experiments with the nuclear acids fixed on the nitrocellulose filters. The biotin treated DNA was determined by the avidin-gold colloid conjugate with the subsequent physical silver amplification or by the streptavidin-alkaline phosphatase conjugate. The sensitivity of both probes was identical and permitted the determination of 5 x 10(-11)-5 x 10(-12) g of the control DNA and 10(-9) g of the hepatitis A virus. The developed test systems were used for detection of the viral RNA in blood from patients.     

Effect of the direction of a preionization current on X-ray emission from a capillary discharge plasma

The effect of the direction of a preionization current on the generation of 469-Å X-ray emission from the plasma of a fast capillary discharge in argon was studied experimentally in the SIGNAL facility (the discharge current I = 25–40 kA and the current rise rate dI/dt ～ 10¹² A/s). The experiments were performed with 3.1-mm-diameter 157-mm-long ceramic capillaries filled with argon at a pressure of 0.2–1.0 Torr.     

Duration of meiotic prophase stages during oogenesis in the newt Triturus cristatus cristatus]

The duration of the early stages of meiotic prophase was determined in the oogenesis of T. cristatus cristatus by means of autoradiography. The oocytes were being investigated during 39 days from the moment of 3H-thymidine injection. It was shown that preleptotene lasts 1--2, leptotene ca. 4, zygotene 5 and pachytene 26 days. When studying the preparations obtained 1 day after the injection of 3H-thymidine, the silver grains were found to be localized over the nuclei at all stages of meiotic prophase; this suggests the amplification of rDNA which begins in leptotene-zygotene and ends in early diplotene.     

Real-time measurements of quartz erosion in experiments modeling heat loads on divertor plates during disruption in tokamaks

Time-resolved measurements of quartz erosion are carried out to determine the density of the energy flux incident onto the sample surface. These data are needed to create a reliable code describing the interaction of a thermonuclear plasma with a solid surface. Experiments were performed in the 2MK-200 facilityunder the program of modeling heat loads on divertor plates during disruptions in tokamaks. A 10-mm-thick plate of fused quartz was exposed to a high-temperature deuterium-plasma stream with the temperature T _i +T _e ≤1 keV, density (5–10)×10¹⁵ cm⁻³ β=0.25, energy density up to 200 J/cm², and power density ∼10 MW/cm². It is shown that the quartz erosion begins almost immediately after the stream reaches the surface. The eroded material shields the quartz surface from further destruction. Under the given experimental conditions, the integral shielding factor (the ratio of the stream energy to the energy reaching the surface) was rather high (about seventeen). As a result, at a stream energy density of ∼150 J/cm², the total erosion depth was about 0.75 μm over 35 μs. Based on the measured time dependence of the erosion depth and the reference data on the thermal conductivity of the fused quartz, the power density incident onto the quartz sample was numerically calculated. __________ Translated from Fizika Plazmy, Vol. 27, No. 3, 2001, pp. 243–250. Original Russian Text Copyright ? 2001 by Arkhipov, Bakhtin, Vasenin, Zhitlukhin, Safronov, Toporkov.     

Distribution of spontaneous and 8-methoxypsoralen-induced sister chromatid exchanges along the length of the 1st chromosome of Chinese hamster cells

Distributions of spontaneous, induced by monoadducts and induced by crosslinks sister chromatid exchanges (SCE) along the first chromosome of Chinese hamster cells are nonrandom. All experimental distributions have low frequency of SCE in centromeric and telomeric regions. It can be explained by specific structural organization of the chromosome. However, there are some differences between experimental distributions. Distribution of SCE induced by crosslinks differs from that of spontaneous SCE. Distribution of SCE induced by monoadducts, unlike other distributions, has an increased frequency of exchanges in the q11 region. This region contains several narrow closely disposed G+ bands. It is possible that monoadducts lead to increasing SCE frequency on G+-G- junctions. Distribution of SCE induced by crosslinks resembles random distribution, except centromeric and telomeric regions. These results lead to conclusion that the mechanisms of formation of spontaneous, induced by monoadducts and induced by crosslinks SCE differ from each other.     

Global 137Cs Pollution of the Territory of Yakutia and Content in the Feed and Tissue of Wild Game

Biology Bulletin - Data on the concentration of 137Cs is obtained from soils, food plants, and muscle tissue of seven species of game animals (wild reindeer, elk, roe deer, musk deer, bighorn...     

Functional organization of the chromomere. II. Effect of choriogonin on RNA synthesis within the limits of the functioning chromomere]

With the aid of 3-H-uridine radioautography, the effect of gonadotropic hormone choriogonin on the synthesis of RNA in the giant granular loop of XII chromosome of the Triturus cr. cristatus oocytes was studied in normal and after pretreatment of the cells with mutagen. Choriogonin, while obviously stimulating the RNA synthesis, has no effect on the cells pretreated with mutagen.     

Patellar reflex: III. Comparison of reflexes in the cases of normal and pathological activation

The influence of voluntary and involuntary tension of remote muscles on the patellar reflex has been studied. The relationship between the patellar reflex amplitude and the energy of striking the patellar tendon reflects the degree of spasticity. It is suggested that associated activation with the reinforcing effect of the Jendrassik maneuver in healthy subjects may be regarded as an approximate model of the excessive background excitation of the motor system in cerebral palsy.     

Investigation of Electrode Erosion Parameters in Direct and Alternating Current Plasma Torches

Plasma Physics Reports - This paper deals with the study of the wear resistance (erosion) of the material of electrodes in direct and alternating current plasma torches. The life time of electrodes...