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O V Sergeev

Publications and source records attributed to O V Sergeev.

8 recordsLinked to original sources
PubMedDate not supplied

Spectrally resolved cathodoluminescence analyses in the optical near-field.

By implementing a scanning near-field optical microscope into the specimen chamber of a scanning electron microscope, cathodoluminescence can be locally detected in the optical near-field. The achievable spatial resolution in this set-up is only limited by the size of the aperture in a coated fibre probe and its separation from the sample, rather than by the energy dissipation volume of the primary electrons and diffusion processes of excess carriers inside the specimen. We demonstrate how electronically active defects in polycrystalline diamond can be distinguished and localized with sub-wavelength lateral resolution by spectral filtering of the cathodoluminescence signal.

Journal Article↗
PubMedDate not supplied

[Effects of dioxins in the development of malignant tumors and disorders of reproductive health of the population].

The mortality caused by malignant tumors in the town of Chapaevsk, characterized by increased level of dioxins in the environment, is statistically higher than the expected values. For men the relative risk of general morbidity is 1.9 and mortality, 1.8; for lung cancer: morbidity, 3.3 and mortality 3.1; for urogenital cancer: morbidity, 3.6 and mortality, 2.6; for gastric cancer: morbidity 1.9 and mortality, 1.7. In women the morbidity and mortality due to breast cancer (relative risks 1.9 and 2.1, respectively) and cancer of the cervix uteri (relative risks 2.1 and 1.8, respectively) are increased. Changes in the reproductive health of residents of this town are as follows: high incidence of spontaneous abortions, appearance of small-for-date babies, and genital disorders in body (cryptorchidism, phimosis, hypospadia, delayed sexual development).

Adolescent↗
PubMedDate not supplied

[Breast cancer in Chapayevsk].

Numerous epidemiological surveys show the ambiguity of evaluation of stable organic chlorine compounds as a risk factor for breast cancer (BC). This is likely to be, to a certain degree, associated with the specific features of performance of epidemiological surveys. The selection of cases of BC from different areas has provided groups with different levels of exposure that as judged from the content of the above substances in the biological environments. Only few epidemiological surveys have been made in the world to assess stable organic pollutants (SOP) as risk factors of BC mainly in occupational groups. In the local areas highly polluted with dioxins, there is evidence for their role as a risk factor of BS only for women living in Sevezo. These findings are in agreement with the results of the surveys made in Chapayevsk. The analytical epidemiological study using a case-control approach has revealed the significance of biological (BC in relatives, childlessness), occupational (women's work at CVZH) and environmental (pollution, the more frequent ingestion of local pork and fish than in the control group) risk factors of BC. In the 1950-1960s, the largest Russian enterprises of chlorine chemistry worked most actively not only in Chapayevsk, but also in towns with plants of chlorine industry, such as Dzerzhinsk, Novomoskovsk, Sayansk, Usolye-Sibirskoye, and others. Ecological and epidemiological studies should be organized in these towns in order to define the value of SOP as a risk factor of BC for general populational groups.

Adolescent↗
PubMedDate not supplied

[The expression of a fragment of the HIV-1 env gene in the cells of Escherichia coli bacteria].

A recombinant plasmid pEK6 determining the synthesis of a hybrid protein the N-terminus of which was represented by full-size beta-galactosidase and C-terminus by HIV-1 gene env virus-specific sequence was constructed. The analysis of lysates of E. coli HB101/pEK6 bacteria in 6% PAAGE revealed additional proteins with molecular weights from 185 to 130 kDa. These proteins interacted with blood serum antibodies of a virus carrier but formed no specific bands with sera from normal donors. Densitometric analysis of polyacrylamide gels stained with Coomassi R250 demonstrated that the level of production of recombinant protein was at least 15% of the total cell protein. Hybrid polypeptides formed poorly soluble inclusion bodies in the bacterial cells. Study of the immunological properties of the recombinant polypeptides showed that immunization of rabbits with these proteins induced antibodies specifically reacting with viral polypeptides with molecular weights of about 82 and 140 kDa. Such features as a high level of synthesis, technologically feasible purification of inclusion bodies, and adequate antigenic properties recommend this preparation for use in the development of diagnostic test systems.

Amino Acid Sequence↗
PubMedDate not supplied

[The RNA electrophoretypes of the rotaviruses circulating in Moscow and Leningrad in the winter of 1987-1988].

Analysis of electrophoretypes of RNA of rotavirus which had circulated in Moscow and Leningrad in the winter of 1987-1988, detected by enzyme immunoassay (EIA), was carried out. RNA electrophoresis was performed in 10% polyacrylamide gel (PAG) followed by silver staining, Most of the strains isolated in Moscow and Leningrad had a long phoretype (67% and 77%, respectively. The greatest variations in PAG mobility were found in segments 2, 3, and 7-9, segments 1, 4, 10, and 11 showed most unchangeable mobility. According to the pattern of segment migration, 3 variants of the long phoretype and 5 variants of the short phoretype were distinguished. In Moscow the ist variant (confluent 2nd and 3rd segments as well as 7th and 8th segments) of the long phoretype was predominant, which was isolated in approximately 70% of all cases of infection; in Leningrad the dominating variant was intermediate between the 1st and 2nd phoretype (slower migration of the 2nd segment). Variants of the sport phoretype were characterized by greater variability and lack of the dominating strain. The potentials of rotavirus RNA electrophoresis as a method of molecular epidemiology are discussed.

Child↗
PubMedDate not supplied

[Pestiviruses].

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Animals↗
PubMedDate not supplied

[An analysis of the blood sera of patients infected with HIV-1 for the presence of antibodies to the gp120 and gp41 sequences].

Blood sera, originating four regions of Russia and Byelorussia and previously tested for the content of antibodies to HIV-1 proteins, were studied in the enzyme immunoassay on the basis of recombinant sequences gp160, as well as on the basis of oligopeptides corresponding to sequences V3 of six HIV-1 strains. The possibility of using sequences gp160, contained in fusion polypeptides synthesized in Escherichia coli cells, for the detection of antibodies in laboratory research was shown. Differences in the reactivity of the sera under study with respect to fragments gp160 correlated with the geographical origin of these sera: similarity between the serum samples from Elista and Rostov and their difference from serum samples collected in other regions were shown.

Amino Acid Sequence↗