Different modes of alkaline hydrolysis of fervenulin and isofervenulin

Unlike rheumycin and fervenulin, isofervenulin and 3-methylisofervenulin are hydrolyzed by aqueous alkalies at the N₍₅₎-C₍₆₎ bond. On acidification of the reaction mixture, the N-carboxy-N-methylcarbamoyltriazines formed are reconverted into the starting isofervenulins, and on basification (pH>10) into methylaminotriazinecarboxamides. A by-product of the alkaline hydrolysis of isofervenulin is a product of the contraction of the uracil ring, namely imidazotriazinone-7a-carboxylic acid.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1555–1559, November, 1987.     

Nitroazines. 6. Direct introduction of indole residues into 6-nitroazolo[1,5-a]pyrimidines

Non-charge-activated 6-nitroazolo[1,5-a]pyrimidines have been reacted with indoles, and the effects of substituents in the azole moiety of the substrate molecule have been examined.For communication 5, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenni, No. 11, 1544–1549, November, 1986.     

New formulation of restricted growth processes

We present a new formulation of a class of growth models-those which evolve according to an exclusion process. This formulation is based upon a transformation of the probability distribution function which involves Grassmann variables. This method is very general and enables one to derive an exact stochastic differential equation for the model of interest. We describe this method using the traffic model as an example.     

13C NMR spectra of the aminoglycoside antibiotic neomycin B,monomycin A,and kanamycin A. Complete assignment of the signals

On the basis of the results of a study of the dependence of the chemical shifts of the signals in the¹³C NMR spectra of neomycin B, monomycin A, and kanamycin A, over a wide pH range (from 1.0 to 10.0) a complete assignment of the spectra signals of these antibiotics has been made. Optimum pH values of solutions are proposed for which the more complete resolution of the resonance signals in the spectra of neomycin B, monomycin A, and kanamycin A is observed. All-Union Scientific-Research Institute of Antibiotics, Moscow. I. M. Sechenov 1st Moscow Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 686–695, September–October, 1980.     

Three-Dimensional Structure of Recombinant Thermophilic Ribokinase from Thermus speсies 2.9 in Complex with Adenosine Diphosphate

Crystallography Reports - The three-dimensional structure of recombinant thermophilic ribokinase from Thermus speсies 2.9 was determined at 2.4 Å resolution using crystals, which were...     

Modeling of Phosphoribosylpyrophosphate Synthetase from Thermus Thermophilus in Complex with ATP and Ribose 5-Phosphate

Crystallography Reports - The positions of the substrates (ATP and ribose 5 phosphate) of phosphoribosylpyrophosphate synthetase from Thermus thermophilus were determined by molecular dynamics...     

Ultrasonic technology for enhanced oil recovery from failing oil wells and the equipment for its implemention

A new method for the ultrasonic enhancement of oil recovery from failing wells is described. The technology involves lowering a source of power ultrasound to the bottom of the well either for a short treatment before removal or as a permanent placement for intermittent use. In wells where the permeability is above 20 mD and the porosity is greater than 15% ultrasonic treatment can increase oil production by up to 50% and in some cases even more. For wells of lower permeability and porosity ultrasonic treatment alone is less successful but high production rates can be achieved when ultrasound is applied in conjunction with chemicals. An average productivity increase of nearly 3 fold can be achieved for this type of production well using the combined ultrasound with chemical treatment technology.     

Resonance method of measuring shear viscoelastic properties of liquid media based on excitation of torsional oscillations in tubes

Possibilities of using torsional oscillations for measuring viscoelastic properties of liquids are discussed. The theory of torsional oscillations of an elastic tube filled with the media to be investigated possessing viscosity and shear elasticity is developed. It is shown that to determine a complex shear modulus it is sufficient to determine the resonance frequency and Q-factor of torsional oscillations. An experimental installation and the results of measurements of viscoelastic modulus of glycerin and oil of one oilfield within the temperature range from −10° to 60°C are given. The experimental installation allows measuring a viscoelastic modulus within the range of acoustic logging frequencies (10–20 kHz). The obtained results are compared with the results of rheometric measurements.