Onega V. Ulianova

LASCA with a small number of scatterers: Application for monitoring of microflow

LASCA, combined with cross-correlation technique, has been applied for high-resolution measurements of the velocity of microflow and its structure in small blood capillaries in vivo. Such measurements have been carried out for the first time behind the resolution limit of the optical system.

Investigation of growth processes in bacterial colonies by the LASCA technique

The method of analysis of the temporal and spatial contrasts of speckle fields formed during the coherent scattering of radiation in bacterial colonies has been adapted to monitor the growth and structure of bacterial colonies by the example of E. coli. A noticeable change in the spatial structures of colonies during their growth has been demonstrated.

Interaction of dynamic low-coherent speckles with the suspension of bacterial cells

Influence of low-coherent speckles on the colonies grows is investigated. It has been demonstrated that effects of light on the inhibition or reactivation of cells are connected with speckle dynamics. The model of free-radicals mechanisms of laser-tissue interaction is simulated by bacteria suspension, containing exogenous photosensitizers in low concentration. The regimes of cell suspension perfusion with purpose of bacteria devitalization, are found.

Biophysical aspects of effects of laser radiation on living systems: II. Effect on Pseudomonas aeruginosa bacteria

It is shown that, taking into account tendencies in the development of new laser technologies, the study of the effect of laser light on microorganisms is a topical and important ecological problem. The results of studies of the role played by the spatiotemporal coherence of laser radiation from the viewpoint of the action of the radiation on bacterial cells are presented. It is found that the coherence of light does not cause any changes in microorganisms under natural conditions (in the presence of photosensitizers in natural concentrations). Based on computer modeling and experimental studies, it is shown that the dynamics of speckles does not affect the stability of bacterial cells.

Biophysical aspects of effects of laser radiation on living systems: I. Effect on laboratory animals

It is shown that, taking into account tendencies in the development of new laser technologies, the study of the effect of laser light on humans and animals is a topical and important ecological problem. The results of studies of the effect of coherent (laser) and partially coherent radiations on the organism of white rats are presented. The results obtained for this model can be extrapolated to humans. Biotesting was performed using the methods of high-spatial-resolution Doppler diagnostics and analysis of the contrast of laser speckles. It is found that the time coherence of light does not affect the cerebral blood flow and does not cause reliable changes in the blood microcirculation in the cutaneous covering. It is also reliably shown that neither monochromatic nor quasi-monochromatic laser radiations change the stability of living systems. It is demonstrated that laser sources in new video technologies have no effect on the blood microcirculation in individual organs.

Using of dynamic speckled speckles with a small number of scatterers for study of suspension of Chlamydia

Theory of formation of speckled speckles at diffraction of focused Gaussian beam in the suspension, containing of Chlamydia trachomatis (CT) is presented. Optical model of scattering of light in suspension of Chlamydia is suggested. Formula for bandwidth of spectrum of intensity fluctuations in speckled speckles is derived. It has been demonstrated, that speckle-microscopy can be used for detection of CT bacteria for any concentration of the relevant cells in suspension.

Detection of the presence of Chlamydia trachomatis bacteria using diffusing wave spectroscopy with a small number of scatterers

Theory of diffusing wave spectroscopy has been firstly adapted to the problem of rapid detection of Chlamydia trachomatis bacteria in blood samples of Chlamydia patients. Formula for correlation function of temporal fluctuations of speckle intensity is derived for the case of small number of scattering events. Dependence of bandwidth of spectrum on average number of scatterers is analyzed. Set-up for detection of the presence of C. trachomatis cells in aqueous suspension is designed. Good agreement between theoretical results and experimental data is shown. Possibility of detection of the presence of C. trachomatis cells in probing volume using diffusing wave spectroscopy with a small number of scatterers is successfully demonstrated for the first time.

Development of principles of two-cascaded laser speckle-microscopy with implication to high-precision express diagnostics of chlamydial infection

Principles of two-cascaded laser speckle-microscopy prospect for application to express diagnostics of chlamydial infection are developed. Prototype of two-cascaded speckle-microscope is designed and tested. Specific case of illumination of bacterial cells by dynamic speckles is considered. Express method of detection of epithelial cells, containing defects, which are caused by Chlamydia trachomatis bacteria, is suggested. Results of improved recognition of C. trachomatis bacteria are discussed.

Optimization of algorithm of coding of genetic information of Chlamydia

New method of coding of genetic information using coherent optical fields is developed. Universal technique of transformation of nucleotide sequences of bacterial gene into laser speckle pattern is suggested. Reference speckle patterns of the nucleotide sequences of omp1 gene of typical wild strains of Chlamydia trachomatis of genovars D, E, F, G, J and K and Chlamydia psittaci serovar I as well are generated. Algorithm of coding of gene information into speckle pattern is optimized. Fully developed speckles with Gaussian statistics for gene-based speckles have been used as criterion of optimization.

Application of LASCA imaging for detection of disorders of blood microcirculation in chicken embryo, infected by Chlamydia trachomatis

Methods of t-LASCA and s-LASCA imaging have been firstly adapted to the problem of monitoring of blood microcirculation in chicken embryo model. Set-up for LASCA imaging of chicken embryo is mounted. Disorders of blood microcirculation in embryonated chicken egg, infected by Chlamydia trachomatis, are detected. Speckle-imaging technique is compared with white-light ovoscopy and new method of laser ovoscopy, based on the scattering of coherent light, advantages of LASCA imaging for the early detection of developmental process of chlamydial agent is demonstrated.