V. Svetukhin

Fiber-optic dosimeter based on radiation-induced attenuation in P-doped fiber: suppression of post-irradiation fading by using two working wavelengths in visible range

The design of a fiber-optic dosimeter, which determines the radiation dose from the difference of radiation-induced attenuation (RIA) Δα measured in a P-doped silica fiber at λ = 413 and 470 nm, is presented along with its first test results under gamma-radiation (dose rates 0.00064 and 0.0066 Gy/s, maximal dose ~2Gy). The dose-dependence of Δα as well as of RIA at individual wavelengths is found to be well described by a power law, the exponent lying in the range 0.90-0.94. In contrast to RIA at individual wavelengths, Δα is found not to depend on dose rate and to decay only slightly on termination of irradiation. Therefore, using Δα for dosimetry is argued to be more promising.

Surface plasmon polariton amplification in a single-walled carbon nanotube

The interaction of a surface plasmon polariton wave of the far-infrared regime propagating in a single-walled carbon nanotube with a drift current is theoretically investigated. It is shown that under the synchronism condition a surface plasmon polariton amplification mechanism is implemented due to the transfer of electromagnetic energy from a drift current wave into a terahertz surface wave propagating along the surface of a single-walled carbon nanotube. Numerical calculations show that for a typical carbon nanotube surface plasmon polariton amplification coefficient reaches huge values of the order of 106 сm-1, which makes it possible to create a carbon-nanotube-based spaser.

Effect of femtosecond laser radiation on morphofunctional state of neoplasm in vitro

The effect of femtosecond laser radiation provided by the Erbium fiber laser with the pulse duration of 10-13 s, peak and average power of 6,0±0,3 kW and 1,26±0,15 mW, respectively, wavelength λ of 1,55 μm has been studied in the experiments on rat ascitic ovarian tumor cell in vitro. Irradiation has been performed at the average intensity of 0,033±0.002 mW/cm2 at two expositions under femtosecond laser radiation of 600 and 900 s. The membrane topology and rigidity of the cancer cells have been estimated with the Scanning probe microscopy (SolverPro, NT-MDT, Russia). Besides, the viability and apoptosis of the cancer cells have been estimated. Free-radical processes and antioxidant enzyme activity have been studied in cancer cell lysate. Femtosecond laser irradiation was established to increases the activity of the Lipoperoxidation - antioxidants system in neoplasm, enhance the apoptosis, decrease the viability, and change cancer cell membrane topology and rigidity in vitro depending on the energy density of the irradiation.

Neutrophils of the patients with cervical cancer after femtosecond laser radiation in vitro

The cytochemical analysis of the aerobic and anaerobic bactericidal, phagocytic activity, phagocytosis completeness, as well as membrane topology and rigidity has been performed with the Scanning probe microscopy (Solver Pro, NT-MDT, Russia) in neutrophils of the patients with cervical carcinoma treated with the Erbium laser radiation at different intensity. The obtained data reveal a significant effect of the femtosecond laser radiation on neutrophil morphofunctional state in patients with cervical cancer. The efficiency of the femtosecond radiation depends on its intensity and clinical stage of the cervical cancer.