თეიმურაზ გოგოლაძე

The EPR spectra of melanin"s free radicals in natural black and hair have been investigated. It is show that the EPR spectrum of black hair is slightly asymmetric singlet with g=2.0035. The EPR spectrum of red hair with g=2.0053 differs frpm the spectru, of black hair.Under the influence of visible in both typs of hair (black and red), the protoinduced free radicals appear, wich indicates an increase in the intensity of already existing EPR spectrum of hair.

The definition of the concentration of pheomelanin in the skin is an issue of great interest because in the case of being influenced by UV radiation, it manifests itself as a prooxidant, causing various skin disorders including melanoma that might help to explain the relatively high incidence of skin cancer among individuals with red hair. The ESR spectra of red hair samples were investigated. It was found that at low microwave power, they are characterized by two types of spectra. Red hair ESR signals result from a superposition of two spectral shapes, a singlet spectrum as a result of the existence of eumelanin and a triplet spectrum as a result of the existence of pheomelanin. At high microwave power, only triplet spectra shape was detected, caused by saturation of the eumelanin singlet. Using different concentration ratios of black to red hair, we measured ESR spectra and plotted the ratio values in each sample against a measured 'g-factor' (experimental). We found that there is a linear relationship between these two parameters. So, it is evident that using these results, the concentration ratio of pheomelanin to eumelanin in a sample of hair can be easily determined by an almost noninvasive method. This can be considered a potential advantage for many practical activities compared with other invasive methods. The concentration dependence curve of pheomelanin (µg/mg) on gexp-factor in an ESR spectrum of hair has been designed, which allows the determination of the amount of pheomelanin in hair of any color.

A wide progress of a photodynamic and laser therapy stimulates a study of an influence of a visible light on human’s skin and hair. The study aimed to create a standard source of a light making it possible to obtain a stable visible light of different frequency spectra – white, red, green and blue. A matrix of four light diodes was used asasource of a light allowing to create almost monochromatic emission of a proper spectrum without any parasitic, infrared or ultraviolet emanations.The device constructed was examined in experimental conditions by means of paramagnetic resonance for a study of an influence of a visible light on free radicals’ processes in dark hair of a human.

The aim of the study was to investigate the kinetics of photo-induced free radicals in the human hair chestnut color with short-term exposure to visible light in different frequency ranges.Studies carried out on human volunteers aged 17-21 years (n=37). Hairs of volunteers of the study were not treated with dyes and other active cosmetic preparations. Hairs bundled in a bun had a length - 1.5 cm, weight - 40 mg.At the beginning background EPR-spectrum of a sample was measured and then hairs were irradiated with visible light (blue, green, red and white) of different wavelength subsequently; exposure duration - 60 minutes; after the exposure the kinetics of photo-induced free radicals was measured within 60 minutes.The radiation source was selected LED array of the four crystals that provides a nearly monochromatic radiation spectrum having no parasitic infrared and ultraviolet radiations

The research aimed at the assessment of diagnostic value of screening tests, evaluation of efficiency of the excisional treatment and determination of predictor risk factors for residual lesions

Our results showed, that EPR method using DMPO spin-trapping is characterized with high sensitivity, wich enables to define anti oxidative activity of very sma;; concentration of major antioxidants in Georgian and foreign red and white wines and in red wine. It was concluded, that red as well as white wines have very high anti oxidative activities. Herewith it has to be mentioned, that anti oxidative activity of red wine does not always correlate with the total concentration of phenol in it and mostly depends on the concentration of different major antioxidants. This was showed up in the results of modeling process for the wine "Nika", a good correlation with the total anti oxidative activity was showed up.

In this work, TiO2 micropowders and nanopowders coated by Ni nanoclusters have been prepared by original electroless deposition method. The presence of Ni nanoclusters at the surface of TiO2 grains was confirmed by measuring the temperature dependence of magnetization. Optical spectroscopy measurements showed significant increase of light absorption in Ni-coated TiO2 nanopowders. Photocatalytic properties of TiO2/Ni powder were studied with electron paramagnetic resonance spectroscopy as well. It was found that deposition of Ni nanoclusters on a mixture of anatase (76%) and rutile (14%) nanopowder provides best results and the optimal Ni deposition time was determined.

Titanium dioxide particles coated by cobalt nanoclusters have been prepared by a novel electroless deposition method. The presence of the Co clusters on the TiO2 surface was confirmed by measuring the temperature dependence of magnetization. Optical spectroscopy revealed a significant increase of light absorption due to the Co clusters. Electron paramagnetic resonance (EPR) spectroscopy was used to quantify the photocatalytic production of radicals, which measurement could be used to determine the optimum cobalt deposition time for maximizing photocatalytic radical production.