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Biomedical subjects

V A Kashpur

Publications and source records attributed to V A Kashpur.

8 recordsLinked to original sources
PubMed2006

Radioactive aerosols released from the Chernobyl Shelter into the immediate environment.

The release of radioactive particles through large gaps in the containment of the destroyed Chernobyl reactor was assessed during two measurement periods. In 1996-1999, a total radionuclide flow rate of 274 Bq s(-1) or 8.64 x 10(9) Bq year(-1) was determined. These releases were predominantly due to (137)Cs (78.5%), (90)Sr (21.1%), and (239+240)Pu (0.4%). The mean activity concentration in the aerosol measured directly at the gaps was about 240 mBq m(-3) with an activity median aerodynamic diameter (AMAD) of 2.4 microm for (137)Cs, 120 mBq m(-3) with an AMAD in the range 3.1-13 microm for (90)Sr, 1.8 mBq m(-3) with an AMAD in the range 3.5-11 microm for (239+240)Pu, and 2.0 mBq m(-3) with an AMAD of 1.5 microm for (241)Am. The resulting total inhalation dose rate calculated close to the gaps was about 100 nSv h(-1). In the near environment, the mean (137)Cs activity in the aerosol was 2.2 mBq m(-3) with an AMAD of 2.2 microm, which gave rise to an inhalation dose rate of about two orders of magnitude lower than the corresponding dose rate at the gaps. Occasionally, however, dose levels were measured in the near environment that were similar to those at the gaps. In 2000-2003, lower activity concentrations were observed. The decrease was more pronounced at the gaps than in the near environment. The results indicate that effective dose due to inhalation must be considered for the dose assessment of construction workers who will be deployed at the Chernobyl site to reconstruct the old or to build the new Shelter, in the future.

Aerosols↗
PubMedDate not supplied

[Globular protein hydration by a differential dielectrometric method].

A differential method is described for measuring dielectric constants and losses in aqueous protein solutions at millimetrerange wavelengths. Employment of the method allows to improve the accuracy of determining the degree of hydratation. A method has also been suggested for taking into account the contribution of ions to the dielectric constant of solutions. The differential method was used to study hydratation of nine globular proteins. The data obtained are compared with the corresponding values provided by other experimental techniques and with theoretical predictions based on some models of hydratation. Good agreement is obtained with results provided by the isopiestic and NMR techniques. The discrepancy shown for hemoglobin is discussed in the paper. As has been shown, the dielectric method registers a monomolecular surface layer of water only. With pH varying between 4.0 and 3.2, a significant increase is observed in the hydratation of serum albumin. Presumably, this effect is connected with a N--F conformational transition.

Electrochemistry↗
PubMedDate not supplied

[Radio-ecological and hygienic assessment of consequences of forest fires in the areas polluted during the Chernobyl accident].

Retransfer of radionuclides on the condensation trails of Chernobyl radioactive fallouts during forest fires has been experimentally evaluated and their mathematical transfer model verified. It has been shown that radionuclide retransfer will make no great impact on additional pollution of an area even under the most unfavourable conditions. The contribution of convective and non-convective components of transfer to the formation of a radioactive aerosol concentration field has been assessed. Time course of changes in the concentration of radioactive aerosol and its dispersive composition are shown in different phases of fire and at different distance from its source.

Aerosols↗
PubMedDate not supplied

[Thermal restructuring and hydration of serum albumin].

Calorimetry and dielectrometry in the millimeter wave range have been applied to demonstrate a possibility for determination of heat capacity of bound water in biopolymer matrices in solution is shown. Variation of the hydration level of human serum albumin caused by the variation of temperature and protein concentration is described. Application of two methods based on comparison of calorimetric and dielectric data on protein solutions at different temperatures and concentrations have produced similar values of the heat capacity of bound water in the protein hydration shell (approximately 3 J/g.K).

Biopolymers↗
PubMedDate not supplied

[Hydration and stability of the B-form of LiDNA].

Hydration and structure of Li DNA in films and solutions have been investigated by methods of IR spectroscopy, piezogravimentry, UHF dielectrometry, and microcalorimetry. The hydration energy and the water sorption range in which the DNA undergoes the transition from the unordered state to the B-form have been determined, making it possible to evaluate the contribution of water molecules of the DNA hydration shell to the total stabilization energy of the DNA helical structure.

Calorimetry↗
PubMedDate not supplied

[Physical properties of the DNA-water system].

The review of original and literary data obtained by the different physical methods on the structure, mechanical, electrostatic and energetic properties of DNA-ions-water system was done. On the basis of the examined results the main problem of DNA structure formation its dynamic and stability were discussed.

Base Sequence↗