A very large diversity space of synthetically accessible compounds for use with drug design programs

We have constructed a very large virtual diversity space containing more than 10¹³ chemical compounds. The diversity space is built from about 400 combinatorial libraries, which have been expanded by choosing sizeable collections of suitable R-groups that can be attached to each link point of their scaffolds. These R-group collections have been created by selecting reagents that have drug-like properties from catalogs of available chemicals. As members of known combinatorial libraries, the compounds in the diversity space are in general synthetically accessible and useful as potential drug leads. Hence, the diversity space can be used as a vast source of compounds by a de novo drug design program. For example, we have used such a program to generate inhibitors of HIV integrase enzyme that exhibited activity in the micromolar range.     

Ozone production and losses in N<Subscript>2</Subscript>/O<Subscript>2</Subscript> mixtures in an ozone generator

Nonunique ozone concentrations at the output of an ozone generator under identical external conditions of barrier discharge activation of N₂/O₂ mixtures but with different prehistories of operating practice and employed gas mixtures are investigated theoretically. An analytical approach is developed to determine the ozone yield with regard for its heterogeneous loss. Plasma-chemical and electron kinetics in the N₂/O₂-mixtures are calculated numerically. The results of numerical calculations are compared to experimental data obtained by the authors. It is noted that the heterogeneous loss of ozone is the probable reason for the observed variety of behavior of О₃ concentrations, depending on prehistory of ozone generator operation, along with the N₂ and O₂ gas flow rates and the specific active power.     

Dynamic fractal structure of emulsions due to motion and interaction of the particles: Numerical simulation

The method of numerical simulation is used to study the geometrical structure of micro-emulsions in the plane. It is found that the interaction between the particles leads to the formation of a dynamic homogeneous fractal structure of the micro-emulsion. In the absence of any interaction between the particles the structure of the emulsion is homogeneous. The interaction energy of the particles at which the fractal inhomogeneity arises is close in magnitude to the interaction energy of the particles in real (e.g., aqueous) micro-emulsions. It is also found that the size of the inhomogeneities (correlation radius) depends on the particle density in the system and is largest for the density of the percolation transition. The numerical simulation data qualitatively coincide with the results of measurements in real micro-emulsions. Zh. éksp. Teor. Fiz. 111, 1314–1319 (April 1997)     

Suppression of auto-oscillations in wind tunnels with open working part

The results are given of an experimental investigation of the acoustic method of auto-oscillation suppression in wind tunnels of closed type with open working part.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 126–132, January–February, 1982.     

Tunnel nanoengine

The motion of nanoparticles involved in resonance electron tunneling is studied. The motion is caused by the particle charging during the process of resonance tunneling. The possibility of controlling the nanoparticle motion is demonstrated, and the mechanism of self-oscillatory particle motion is considered.     

Fractal structure of large-scale variability of wind-driven waves according to laser-scanning data

Results are presented for experimental laser-scanning investigations of the statistical characteristics of wind-driven ocean waves. The method involves counting the number of specular points during scanning of the sea surface by a narrow laser beam on a moving ship. The data analyzed are the set of specular points recorded along a track traced out by the laser beam as a result of the motion of the ship and the scanning beam. A prominent feature is the large-scale variability of the number of specular points and the self-similar nature of the process over a rather wide range of spatial scales. A fractal analysis of the process shows a clear power-law interval in the spatial spectrum of the distribution of specular points.     

Photometric Determination of Chlorine in a Gas Flow in the Presence of Ozone

A method was proposed for the determination of chlorine in a gas mixture containing ozone. The method is based on passing the mixture before absorption with a potassium iodide solution through a furnace, where the ozone is decomposed. The concentration of chlorine at the outlet of the furnace is determined photometrically.     

Acid Catalysis in Reaction of Ozone with Chloride Ions

The kinetics of the interaction of ozone with aqueous solutions of chlorides resulting in Cl₂ evolution to the gas phase was studied. The reaction of O₃ with Cl^– is accelerated by H⁺ ions. The effects of the concentrations of H⁺ and Cl^–, the ionic strength, and temperature (ranged from 7 to 60°C) on the reaction rate were studied. A mechanism explaining the experimental kinetics was proposed. The acid catalysis is due to the formation of the HO₃Cl complex, which is in equilibrium with H⁺, O₃, and Cl^–. The constants of reactions involved in the proposed mechanism were determined.