Absorption of infrared radiation by a thin water layer]

The unhomogeneous distribution of infrared absorption in a thin water layer and its time instability were explained. The parameters of interribbon interaction in the case of thin water layers with bound influence were evaluated.     

Comparative effectiveness of antioxidants in protecting the bacterial plasmatic membrane from the active froms of oxygen

The effect of hydroxyl radicals OH. generated by the decomposition of H2O2 by Fe2+ ions (Fenton reaction) on the barrier properties of plasma membranes of Escherichia coli cells K-12 was studied by electroorientation spectroscopy. It was found that the administration of hydrogen peroxide led to the disturbance of the barrier properties of plasma membranes only when the cells were preincubated with Fe2+ ions and their constant concentration in the system was maintained by ascorbate or dithiotreitol (150-500 microM). The extent of the toxic action on plasma membranes depended on the concentration of reacting elements and the substance used as a reducer Fe2+. The efficiency of protection of antioxidants of different classes (enzymic, SH-containing, and phenolic compounds) against the toxic action of hydroxyl radicals on plasmatic membranes was shown.     

Effect of treated with weak magnetic field aqueous salt solutions on the intrinsic fluorescence of bovine serum albumin. Isolation from solutions and partial characterization of the biologically active fluorescing fraction

It was shown that water with additions of Ca2+, Na+, K+ and Cl- ions preliminarily treated with weak combined constant (42 microT) and low-frequency alternating (0.06 microT) magnetic fields affects the intrinsic fluorescence of bovine serum albumin, the magnitude of the effect being dependent on the frequency of the alternating field and ionic composition of the aqueous salt solution. A practically complete transfer of the effect through a small portion of the solution treated with magnetic fields was revealed. It was also found that after magnetic treatment, the solution contains a rather large (molecular mass 700-900 D) and stable molecular associate, which possesses, at least partially, the properties and characteristics inherent in the whole solution that were as acquired as a result of magnetic treatment.     

Analysis of the contribution of forest pathways to the radiation exposure of different population groups in the Bryansk region of Russia

The experience gained in the aftermath of serious radiation accidents shows that forests are an important source of external and internal exposure of the affected population. This paper presents the results of an assessment of the major radiological consequences for forests of Russia, most heavily contaminated after the Chernobyl nuclear power plant (ChNPP) accident. Illustrated in the Novozybkovsky district of the Russian Federation, the significance of different forest exposure pathways is estimated and the doses resulting from forest pathways are compared with the doses from agricultural products. It has been found that the contribution of mushrooms and berries to the internal doses of the population, relative to the doses from agricultural products, varied from 10–15% in 1987 to 40–45% in 1996. The results indicate large differences in internal exposure of members of the ”critical groups” and ”normal population”, increasing with time after deposition. Data are presented that give information on the contribution of forests to the collective doses of inhabitants of the area under consideration. It has been shown that for 10 years after the accident (1987–1996), the contribution of forest products to the collective dose of the rural population living in contaminated forests of the Novozybkovsky district, amounts to about 20% (213 person Sv) of the total collective dose of internal and external exposures. However, a potential impact of these products including the dose from exported products is much higher and might reach 659 person Sv. It has been found that in the long-term after the ChNPP accident, serious attention should be given to forest countermeasures, and restoration strategies should be selected on the basis of a combined analysis of the effectiveness of forest and agricultural countermeasures. Received: 16 March 2000 / Accepted: 10 September 2000     

Analysis of factors determining the biological availability of 137Cs in forest ecosystem soils

On five forest plots varying in species composition of woody plants and soil properties, 137Cs accumulation by vegetation of the forest understorey has been studied. Differences in 137Cs availability for root uptake are shown to be dependent on a vertical distribution of 137Cs content over the soil profile, percentage of exchangeable 137Cs and distribution of plant root systems (fungous mycelium) in soil. A 137Cs-bioavailability index is suggested and its non-linear relationship with 137Cs transfer factors to different plant species in the understorey is shown.     

Effect of electromagnetic waves in the centimeter range on the production of tumor necrosis factor and interleukin-3 in immunized mice

The effect of prolonged treatment with weak microwaves on the production of tumor necrosis factor and interleukin-3 in peritoneal macrophages and T cells of male NMRI mice twice immunized by affinity-purified carboanhydrase was studied. Against the back ground of a high titer of antibody production, a significant increase in the production of tumor necrosis factor in peritoneal macrophages and splenic T lymphocytes of immunized mice was revealed, and a much stronger effect was observed for irradiated immunized animals. A tendency to increased secretion of interleukin-3 for unirradiated and irradiated immunized animals was found; in the latter group of animals, the effect being more pronounced. The stimulation of production of the cytokins, especially tumor necrosis factor, by combination of antigenic stimulation and microwaves can be used in adjuvant therapy of various immune diseases.     

Vibrational structure of absorption spectra of water in visible region

The results of the study of the temperature dependence of water absorption spectra in the visible region and in the region of vibrational overtones are discussed.     

The biophysical aspects of reconstructing a single cell by the methods of cell engineering

The problem of the low efficiency of mammalian cloning is discussed with emphasis on the need of expert assessment of every step in single cell reconstruction, beginning with microsurgical manipulations. Experimental proof is provided for the impairment of cell integrity upon its fixation for microsurgery by the negative pressure in a conventional holding pipette. The ensuing leakage of the cell contents is shown to depend on the value of negative pressure, the duration of holding, and the size of the holder orifice. An alternative method of cell fixation is proposed, taking advantage of the capillary forces in the holding micropipette. This reduces the holding effort by two orders of magnitude and raises the cell survival upon microsurgery at least to 92%. To alleviate cell damage by instrumental invasion, a new technique is proposed for making micropipettes. Another novel method is offered for pipette filling with viscous liquid such as DNA solution, which allows continuous injection of more than 1000 cells.     

Multimodal effects of nearly complete geomagnetic field deprivation on fission of the planarian <Emphasis Type="Italic">Dugesia tigrina</Emphasis>

The rate of asexual reproduction of planarians (fission) did not change upon total deprivation of the geomagnetic field (induction ±5 nT), but was 1.5–2-fold higher than in the control upon attenuation to 100–300 nT; the stimulatory effect disappeared at 400–600 nT, was almost restituted at 0.8–1.5 μT, and zeroed again at 3 μT.