Intravenous laser irradiation of blood (ILIB) by helium-neon laser (HNL) with &lgr;=632.8 nm, 2.5-4.5 mW at the light
guide outlet was employed to investigate ILIB influence on blood oxygen transport (BOT), hydro-ion balance for normal
rabbits and after modeling of local ischemia of brain (LIB). Marked improvement of disturbances typical for ischemia
was revealed for both hydro-ion balance characteristics and BOT parameters such as oxygen tension (pvO2), oxygen hemoglobin saturation (svO2), pvO2 of blood under its 50% saturation by O2 (p50) and tendency was found to their normalization.
To identify the molecular photoacceptors and the mechanisms of primary photoreactions the spectral data were
used both in visible and infrared regions. On the basis of spectral analysis hemoglobin was discussed as a possible
photoacceptor when blood is irradiated with HNL radiation. Variations in the redox properties of respiratory chain components
were considered as primary mechanisms of light action on photoacceptor molecules that initiated a cascade of
secondary reactions controlling cellular homeostasis parameters.
Laser-magnetic field action on blood in vivo was studied within a range 440-650 nm. The primary mechanisms of laser-magnetic
blood irradiation in vivo were studied at (1) laser and non-laser irradiation with light of various wavelengths,
(2) autohemo-magnetic-therapy, (3) multicolored over-vein irradiation of the blood, (4) the laser-magnetic field actions.
Hemoglobin is considered as primary photoacceptor of radiation. The dependence of effectiveness of laser action on
light wavelength was compared with known action spectra for blood photostimulation. Magnetic field enhancement of
the laser- induced reactions was discussed as result of magnetic field influence on ferromagnetic hem inclusions and on a
structure of hemoglobin peptide chains. Hemoglobin oxygenation or deoxygenation processes were analyzed as a first
stage of the therapeutic effects depending on a preceding hemoglobin oxygenation degree at pathological state. The laser-
magnetic irradiation causes tendency to the normalization of these process. It is proposed that the secondary reactions
are initiated by reversible structural changes of erythrocytes membrane caused the strong hemoglobin absorption.
The oxygen quenching of aromatic hydrocarbon excited states was studied with emphasis on the mechanisms of the
quenching processes in the vapor phase. The changes in decay rates and intensities of laser-induced fluorescence and
delayed fluorescence with the O2 pressure growth were determined. The relationships between kq and the photophysical
parameters of molecules as well as the changes in the free energy for intermolecular full electron transfer (▵Get) were
analyzed for gas-phase systems under study.
To identify the molecular photoacceptors and the mechanisms of primary photoreactions the relationships were discussed between the changes both in visible and infrared spectra and in the molecular structure of blood and blood components after intravenous laser irradiation.
Application of multistep schemes for excitation of polyatomic molecules makes it possible to improve bond-selected excitation with light. Fast collisional energy transfer is one of the most important processes that hinder bond-selected reactions. Collisional effects after multistep laser excitation of molecules is an active area of research at present time because of both the little studied characteristics of relaxation processes for polyatomic molecules in vibrational quasi-continuum and possible practical applications. In this report, the intensities and decay rates of the time-resolved delayed fluorescence (DF) activated by several ways of multistep laser excitation of complex organic molecules (acetophenone, benzophenone, anthraquinone, fluorenone) were used to study collisional processes after nonequilbirium vibrational excitation of triplet molecules mixed with bath gases N2, CO2, NH3, H2O, C2H2, CCl4, C6H6, C5H12, many of which participate in important chemical and photochemical organic molecules transformations that occur in nature. The quantitative characteristics of collisional processes in vibrational quasicontinuum were obtained. Analysis was made of rate constant dependences for near-resonant vibration-vibration (V-V) and vibration-translation (V-T) energy transfer processes on such factors as: properties of excited molecules and bath gases; vibrational energy of excited molecules; temperature, etc. Conclusions were made that collisional efficiencies of V-V process in mixture with polyatomic bath gases were governed by long-range attractive interactions. Upper levels, initially populated following laser excitation relaxed to vibrational distribution after several collisions. Majority of the collision took place only in V-T transfer of relatively small energies. The regularities of this process reflected the dominant role of short-range repulsive forces.
Mechanisms and rates of laser-induced gas-phase reactions of vibrationally excited triplet ketones were studied after adding electron and hydrogen donors using time-resolved delayed fluorescence. The influence of various bimolecular competing processes on DF quenching was analyzed.
KEYWORDS: Molecules, Carbon dioxide lasers, Energy transfer, Molecular lasers, Gases, Luminescence, Information technology, Argon, Pulsed laser operation, Molecular energy transfer
Intensities and decay rates of delayed luminescence (DL) initiated by a pulse of N2 laser or CO2 laser were employed to probe collisional relaxation of complex molecules (benzophenone -- C13H10O, acetophenone -- C8H8O, anthraquinone -- C14H8O2) diluted with bath gases: Ar, C2H4, SF6, C5H12, CCl4. It was shown that time resolution about 10-8 sec permit one to divide the V-V and V-T processes for such large and complex molecules, the relaxation occurs in two stages. Upper levels relax through V-V transfer, which completes after several collisions. The collisional efficiencies of V-V process had the values typical for supercollision. The average energies transferred per collision, <(Delta) E>, well correlate with predictions of the simple ergodic collision theory of intermolecular energy transfer. The majority of energy transfer collisions involve V-T/R transfer of relatively small energies. The CO2 laser excitation method to initiate the DL allowed to obtain only V-T CET quantities because of lower time resolution.
The experimental approaches to studying both collision- induced and collision-free vibrational relaxation after excitation of polyatomic triplet molecules by CO2 laser and by ruby laser pulses are used to discuss the processes of vibrational energy redistribution in quasicontinuum of vibrational states.
The photoacoustic gas analyzer utilizing an industrial carbon-dioxide waveguide laser was presented to quantitatively determine low concentration of gaseous pollutants in real air. The PA resonant H-type cell design was described. By analyzing the dependence of the PA signal on a modulation frequency, the most suitable acoustic resonance was chosen for practical use. The spectrophone characteristic constant A was determined for various carbon-dioxide laser lines which coincided with air pollutants absorption lines. The schematic diagram of the full- automatic PA gas analyzer was considered, and the interconnection of its units was outlined. It is shown that PA gas analyzer concentration characteristic is linear in a wide concentration range overlapping three orders of magnitude; pollutants detection threshold values are considerably less than their utmost admissible concentrations in air of the living zone. An idea of using Stark's modulation at atmospheric gas pressure analysis is examined.
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