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.     

Role of hydrolytic degradation of polylactide drug carriers in developing micro- and nanoscale polylactide-based drug dosage forms

The present analytical survey explores different aspects of hydrolytic degradation of drug dosage forms (DF) based on polylactides, homopolymers of lactic acid (PLA) and copolymers of lactic and glycolic acids (PLGA). The study includes various scientific data from multiple sources describing the effect of the PLGA nanocarrier hydrolytic degradation rate on the profile of drug release from the DFs intended for intravenous and intramuscular administration, including micro- and nanoparticles, and implants. The following aspects are explored in the review: design of experiments aimed at studying the hydrolytic degradation kinetics of PLGA carriers; commonly employed analytical methods; interpretation of the mechanism of PLGA-based DF hydrolytic degradation; factors that influence the hydrolytic degradation rate of PLGA drug carriers as part of DFs; interrelation between the processes of polymer carrier hydrolytic degradation and drug substance release from the PLGA-based DFs.

     

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.     

Effect of laser radiation on living systems: Role of light coherence

The influence of spatial and temporal coherence, as well as speckle dynamics, on animal organisms is studied in detail. Our theoretical and experimental studies reveal no biophysical evidence of the influence of light coherence on living systems at any level, as well as no specific effects caused by laser radiation. The effects of laser therapy used for treatment of a wide range of diseases of humans require further detailed investigation and possibly a revision of the existing concept.