Influence of Xenon on Survival of Sperm of Common Frog Rana temporaria during Slow Freezing.

We studied the effect of xenon on the survival rate of the spermatozoa of the common frog Rana temporaria during slow freezing with saturation of the suspension with xenon at a pressure of up to 1.2 bar. The cryoprotective properties of xenon were analyzed in comparison with nitrogen. No specific cryoprotective effect of xenon was revealed. Viability of spermatozoa pretreated with xenon at atmospheric pressure (0 bar) or under excess pressure of 0.6 bar and frozen in a cryoprotective medium with dimethylformamide, sucrose, and BSA did not differ significantly. The use of overpressure of xenon of 1.0 or 1.2 bar in the pretreatment and freezing process significantly impaired viability of the biomaterial.

[On peculiarities of temperature dependences of water spectra in the terahertz frequency domain].

We analyzed spectra of light and heavy water at temperatures from 4 up to 50 degrees C in a frequency range of 0.15 to 6.5 THz. It was shown that the amplitude of high-frequency relaxation absorption band with its maximum at 0.5 THz extends with increasing, temperature and this temperature dependence for light water has a marked feature at 35-40 degrees C as a sharp growth. This fact is noteworthy because this range corresponds to physiological values of a body temperature of the warm-blooded organisms. At the same time, the analogous temperature dependence for heavy water in the considered temperature range lacks this particular feature. Thus, the water with its properties differs significantly not only from other fluids, but also from its own isotopologues.

[Calculation of the portion of free water molecules in water solutions by means of spectral analysis].

In this paper we present the results of spectral studies of water solutions and water at different temperatures. The calculation method for estimation of the portion of free water molecules is offered. The method is based on the analysis of transmissions spectra features in the terahertz region. The calculation using the proposed method shows that the portion of free water molecules at room temperature ranges from 10 to 16% for a variety of water solutions. In case of pure water, the temperature increase from 20 to 50 degrees C results in the increase of the free molecule fraction from 12% to 19%. Moreover, the increase in the number of free water molecules within a specified temperature range exhibits significant nonuniformity: the most intense growth was observed in the range of 30-40 degrees C. This is particularly interesting because this temperature range includes the optimum temperatures for the existence of warm-blooded animals.

[On singularities of molecular relaxation in water solutions].

In this paper, we analyzed spectra of liquid water and water solutions in a frequency domain, characteristic of the collective dynamics of water molecules (from 0 to 200 cm(-1)). Particular attention is paid to the relaxation processes, one of which is observed in the terahertz region of the spectrum (approximately 5-50 cm(-1)). The physical essence of this process at the molecular level is still unclear. Based on data obtained this process is strongly suggested to interpret as a monomolecular relaxation of unbound water molecules.