Solubility Behavior in Ternary Water-Salt Systems under Sub- and Supercritical Conditions

Summary.  Two main types of binary systems with distinctive solubility behavior under sub- and supercritical conditions were used to subdivide ternary water-salt systems into three classes. Characteristic features of solubility behavior and phase equilibria in ternary water-salt systems of each class at temperatures above 200°C are discussed on the basis of available experimental data and some conclusions obtained as a result of theoretical derivation of fluid and complete phase diagrams. Corresponding author. E-mail: Valyashko@IGIC.RAS.RU Received September 25, 2002; accepted (revised) November 28, 2002 Published online April 24, 2003 RID="a" ID="a" Dedicated to Prof. Dr. H. Gamsjaeger on the occasion of his 70^th birthday anniversary     

Identifying the domains of dynamic instability for inhomogeneous shell systems under periodic loads

The paper outlines an approach to identifying the principal dynamic-instability domain for systems composed of shells of revolution with different shapes under axisymmetric periodic loading. The original problem is reduced to one-dimensional eigenvalue problems with respect to the meridional coordinate. Results of calculations for a specific shell system are presented     

X-ray diffraction study of the complexes of SAICAR synthase with adenosinetriphosphate

The three-dimensional structures of two enzyme-substrate complexes of SAICAR synthase from the yeast Saccharomyces cerevisiae with adenosinetriphosphate (ATP) prepared under different conditions were studied by X-ray diffraction analysis and then refined. An enzyme molecule was shown to contain two binding sites of ATP. One of these sites is located in the central cavity of the enzyme molecule and apparently binds the ATP molecule directly involved in the enzymatic reaction. In the complexes, the phosphate groups of ATP occupying this site adopt different conformations depending on the Mg²⁺ concentration. The functional role of the second binding site located at a distance of approximately 15 Å from the first site away from the central enzyme cavity has not been understood as yet. It might be that the second site perform the regulatory role in enzyme functioning.     

Contact Interaction Between a Laminated Shell of Revolution and a Rigid or Elastic Foundation

A method is proposed to solve the contact problem for laminated anisotropic shells of revolution. The method is based on a two-dimensional model that accounts for transverse shears and reduction. Also the method is based on the method of successive approximations, the generalized pseudo-force method, and a numerical-analytical method of solving boundary-value problems. The results obtained for a cylindrical shell of complex thickness structure are compared with those obtained in three-dimensional formulation__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 5, pp. 68–75, May 2005.     

Phase diagram of BaCl<Subscript>2</Subscript>-NaCl-H<Subscript>2</Subscript>O at temperatures up to 530°C and pressures up to 150 MPa

Experimental studies of high-temperature phase equilibria in the BaCl₂-NaCl-H₂O made it possible to determine the conditions of heterogenization of homogeneous supercritical (SC) fluids spreading from the BaCl₂-H₂O binary subsystem of type 2 and to reveal the continuity of the transformation of gasliquid equilibria into equilibria of phase separation in SC environment. Comparison with the characteristics of the K₂SO₄-KCl-H₂O system suggests that ternary systems with one volatile component formed by binary subsystems of type 2 with phase separation and of type 1 without separation have the same type of phase diagrams.     

High-temperature equilibria and critical phenomena in the Na2CO3-NaCl-H2O and Na2CO3-Na2WO4-H2O systems

Phase equilibria in the Na₂CO₃-NaCl-H₂O and Na₂CO₃-Na₂WO₄-H₂O ternary systems formed by type 1 salts (NaCl, Na₂WO₄) and a type 2 salt (Na₂CO₃) were experimentally studied at temperatures from 425 to 500°C and pressures from 30 to 160 MPa with the contents of type 1 salts from 10 to 30 wt %. Transition from supercritical homogeneous fluid equilibria of the Na₂CO₃-H₂O system to heterogeneous equilibria of the title ternary systems was studied in the presence or absence of liquid phase immiscibility in the type 1 subsystems.     

X-ray diffraction study of the complex of the enzyme SAICAR synthase with substrate analogues

The three-dimensional structure of the complex of the enzyme SAICAR synthase with analogues of natural substrates, namely, phosphoribosylaminoimidazolecarboxamide (AICAR) and succinic acid, was determined and refined by methods of protein crystallography. Two AICAR-binding sites were revealed in the protein molecule. One of these sites is located in the active center of the enzyme in the vicinity of the ATP-binding site, which has been found in the complex of SAICAR synthase with ATP that had been studied earlier. The second AICAR-binding site is located at the periphery of the protein molecule and coincides with the additional ATP-binding site present in the complexes studied earlier. The binding site of succinic acid was revealed in the active center of the enzyme in the vicinity of the AICAR molecule. The electron density distribution for the AICAR molecule in the active center is indicative of the possible lability of the atomic group of the adenine base.     

X-ray diffraction study of the complex of the enzyme SAICAR synthase with the reaction product

The three-dimensional structure of the complex of the enzyme SAICAR synthase with the product of the enzymatic reaction, SAICAR, was solved and refined by methods of protein crystallography. The SAICAR-binding site in the active site of the enzyme was found. The amino-acid residues providing the binding of the reaction product with the protein were revealed. These residues were compared with those involved in the substrate binding in the complex with AICAR and succinic acid studied earlier.