Reactive nitrogen species produced in water by non-equilibrium plasma increase plant growth rate and nutritional yield

Water quality, mineralization, and chemical composition, particularly pH and nitrogen compounds each, play a crucial role in plant development and growth. Treatment of water with non-equilibrium discharges results in the change of its properties and chemical composition, which in turn may affect plant growth process and subsequently agriculture produce quality. Both thermal and non-thermal discharges generated in air or in water produce a number of reactive neutral and charged species, electric fields, and ultraviolet radiation. Plasma treatment of water results in significant change of its properties like pH, oxidation–reduction potential (ORP), conductivity, and concentration of reactive oxygen and reactive nitrogen species (ROS and RNS). Here we report the results of an experimental study of the effect of water treated with different atmospheric plasmas on germination, growth rates, and overall nutritional value of various plants. In the study we have used three types of plasmas: thermal spark discharge, gliding arc discharge, and transferred arc discharge. It is shown that the effects of these plasmas on chemical composition of various types of water are qualitatively different. Non-thermal gliding arc discharge plasma results in lower (acidic) pH, and production of significant amount of oxidizing species (e.g. H₂O₂). Gliding arc discharge also causes significant acidification of water, but it is accompanied by production of reactive nitrogen species (NO, NO₂^? and NO₃^?). Spark discharge treatment results in neutral or higher (basic) pH depending on initial water composition, and production of RNS.     

Technique for detecting changes in fluorescence lifetime by means of optoelectronic circuit auto-oscillation

We present a new, simple, inexpensive, and highly precise approach to excited-state fluorescence-lifetime-based measurements. The detection system consists of a closed-loop optoelectronic arrangement containing a radio frequency resonance amplifier, a fluorescence excitation light source, a fiber-optic delay line, and a photodetector. The system exhibits auto-oscillations in the form of intensity modulation. The oscillation frequency varies with the modulation phase shift of the fluorescent light. This frequency is used as the detection parameter, which is advantageous because frequency may be measured easily, inexpensively, and with high precision. This technique is well suited for chemical or biosensor applications.     

Chaos and neural dynamics

Small neural networks (central pattern generators), which control rythmic behavior of animals, are considered. The mechanisms responsible for regularity, reliability, and plasticity of such behavior (swimming, running, walking, etc.) are analyzed. New data on the origin of regular cooperative behavior of neurons are obtained by using methods of nonlinear dynamics.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 6, pp. 757–770, June, 1996.