TERAHERTZ RADIATION INFLUENCE ON THE GROWING OF NEURITES

Our research was devoted to the impact of broadband pulsed THz radiation in the frequency range of 0.05 to 2 THz on the neurite growth in the sensory ganglia of 10-12-day chicken embryos. Dependence of changes in functional responses of cells on the average output power has been found

Fabrication and characterization of biotissue-mimicking phantoms in the THz frequency range

Abstract The study revealed the most promising candidates for phantoms mimicking different biological tissues in the terahertz frequency range. Closest to biological tissues in terms of the refractive index appeared to be gelatin-based gels; in terms of the absorption coefficient they were agar-based gels. Gelatin is more stable in time, but requires special storage conditions to limit water evaporation. The dense structure of the agar-based phantom allows its use without mold and risk of damage. However, agar is a nutrient medium for bacteria and its parameters degrade even when the phantom form and water content are retained. Use of liquid suspensions of lecithin and milk powder are found to be extremely limited

Agar and Silica Gel Based Biotissue-mimicking Phantoms in THz Frequency Range

International audienc

Study of blood plasma optical properties in mice grafted with Ehrlich carcinoma in the frequencyrange 0.1–1.0 THz

International audienceIn the course of in vitro studies of blood of laboratory animals with progressing Ehrlich carcinoma, we have revealed the change of the blood plasma optical properties in the THz range, which can be used for developing the express diagnostics of the presence of oncological diseases. An applied software package is elaborated that allows the phantoms of biological samples having a complex structure to be numerically simulated and the parameters of the electromagnetic wave reflected from these samples in the THz frequency range to be calculated

SPECTRUM RESEARCH OF DNA MOLECULE IN THE TERAHERTZ FREQUENCY DOMAIN

Spectrum research of degraded DNA of herring in the range 0.1-1 THz was done. DNA native absorption lines were obtained. Lines, responsible for interaction with water and conformational changes, were identified

AMINO ACIDS IDENTIFICATION IN THE HUMAN SKIN BY SPECTRA APPLICATION OF 0,05-1,2 THZ RANGE

Spectra of human skin and tableted preparations of amino acids in 0,05 1,2 THz range are obtained by terahertz spectroscopy method with time resolution. Comparison of the amino acids spectral lines is made for their identification in the skin. It is shown that the following amino acids are the most clearly visible in the skin spectrum: tryptophan, cysteine, alanine, glycine, phenylalanine and histidine. Terahertz spectral lines of the mentioned amino acids are associated with molecules oscillating modes, caused by chemical reactions, hydration processes and molecules conformal changes in the human skin. Determination of amino acids spectral lines and other specific molecules, involved in the metabolic processes of the skin, is necessary for the development of terahertz diagnostic tool with maximum sensitivity and selectivity

Self-damping of the relaxation oscillations in miniature pulsed transmitter for sub-nanosecond-precision, long-distance LIDAR

Abstract Peak power is a critical factor for sub-nanosecond-pulsed transmitters utilizing laser diodes (LD) and applied to long distance LIDARs (light detection and ranging) for drones and automotive applications. Receiver speed is not anymore a limiting factor thanks to replacing linear (typically avalanche) detectors and a broad-band amplifier with a single photon avalanche detector (SPAD). Consequently the transmitters become the bottle neck in the resolution and ranging. The simplest and lowest-possible-cost transmitter consists of a switch, an LD, a storage capacitor C, and unavoidable parasitic loop inductance L. In the resulting resonant circuit, the principal problem consists of suppressing relaxation oscillations. Traditional way of oscillation damping reduce peak current and increase the pulse width. Here we show that specific transient properties of a Si avalanche switch solves the problem automatically provided the inductance is sufficiently low. This finding advances the state-of-the-art by reaching 90 W/1ns/200 kHz pulses from a miniature low-cost transmitter based on Si avalanching bipolar junction transistor (ABJT). Besides, the same self-damping effect may be realized in other switches maintaining significant residual voltage despite of fast current reduction

Multimodal optical diagnostics of glycated biological tissues

Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia accompanied by the disruption of carbohydrate, lipid, and proteins metabolism and development of longterm microvascular, macrovascular, and neuro pathic changes. This review presents the results of spectroscopic studies on the glycation of tissues and cell proteins in organ isms with naturally developing and model diabetes and in vitro glycated samples in a wide range of electromagnetic waves, from visible light to terahertz radiation. Experiments on the refractometric measurements of glycated and oxygenated hemoglobin in broad wavelength and temperature ranges using digital holographic microscopy and diffraction tomography are discussed, as well as possible application of these methods in the diabetes diagnostics. It is shown that the development and implementation of multimodal approaches based on a combination of phase diagnostics with other methods is another promising direction in the diabetes diagnostics. The possibilities of using optical clearing agents for monitoring the diffusion of substances in the glycated tissues and blood flow dynamics in the pancreas of animals with induced diabetes have also been analyzed