Supramolecular systems based on poly(ethyleneimines) and calix[4]resorcinarenes with alkylphosphonate fragments. Aggregation and catalytic activity

Aggregation in poly(ethylenimine)-calix[4]resorcinarene-water-DMF systems was studied by the methods of conductometry and dynamic light scattering. The sizes (radii) of the aggregates formed and the critical micelle concentrations were determined. The catalytic activity for these systems in the hydrolisys of phosphorus acid esters was shown. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 924–931, May, 2007.     

Influence of frustrations on the thermodynamic properties of the low-dimensional Potts model studied by computer simulation

Influence of disorder in the form of frustration on the thermodynamic behavior of a two-dimensional three-vertex Potts model has been studied by the Monte Carlo method, taking into account the nearest and next-nearest neighbors. Systems with linear sizes of L × L = N (L = 9–48) on a triangular lattice have been considered. It has been shown that in the case of J₁ > 0 and J₂ < 0 frustrations appear in the spin system within the interval of 0.5 ≤ |r| ≤ 1.0. The model undergoes a phase transition outside this region.     

Thermodynamic and magnetic properties of a three-state Potts model on a triangular lattice with next-neighbor interactions

Physics of the Solid State - Using Monte Carlo calculations, we study the thermodynamic and magnetic properties of 2D structures that can be described by a three-state Potts model on a triangular...     

Control of the catalytic effect of cetyltrimethylammonium bromide micelles by the addition of background electrolyte and nonionic surfactant

The variation of the microscopic properties (surface potential, micropolarity, etc.) of the interface of cetyltrimethylammonium bromide micelles upon the addition of a background electrolyte or the nonionic surfactant Triton X-100 decreases the rates of ion-molecular reactions, namely, alkaline hydrolysis of carboxylic acid esters and tetracoordinate phosphorus acid esters, and results in the shift of acid-base equilibria. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1933–1940, October, 2007.     

Procedure for setting control for the turnover of new,potentially hazardous psychoactive substances. Detection of metabolites of a new APINAC psychoactive compound in rat urine by gas and liquid chromatography with mass spectrometry detection

The appearance of a new APINAC compound (AKB-57, ACBL(N)-018, adamantan-1-yl-1-pentyl-1H-indazol-3-carboxylate) in the Russian market of psychoactive drugs led to the need in setting measures of state control over its turnover and in solving the problem of categorizing this compound as a potentially hazardous psychoactive substance. To establish these control measures, it was necessary to determine the appropriate chromatographic–mass spectrometric characteristics and to search for its metabolites for their subsequent automated detection. The structure of an APINAC molecule has significant similarity with the molecules of other synthetic cannabinoids. In this paper, primary information on the metabolism of APINAC in the body of rats is presented. A number of putative metabolites, which are the products of hydrolysis of the initial structure and additional monohydroxylation of these products, carbonylation and carboxylation of the lateral N-pentyl chain of indazole-containing metabolites, were detected in rat urine by liquid chromatography–mass spectrometry in the mode of measurement of exact masses and gas chromatography–mass spectrometry. It was found that the formation of glucuronides is characteristic for 1-adamantol and its monohydroxylated metabolite and for the indazole-containing product of hydrolysis of APINAC. The presented mass spectra and retention characteristics of the detected metabolites can help in the detection of these (or similar) compounds in human urine.     

Elastic Modulus of Nanofiller in Polymer-Matrix Composites

Russian Physics Journal - The paper explores the stiffness of the nanofiller particle aggregates in polymer matrix composites, such as particulate reinforced, carbon nanotube polymer and graphene...     

Computer Simulation of Critical Behavior of Two-Dimensional Weakly Diluted Antiferromagnetic Potts Model on a Triangular Lattice

Physics of the Solid State - The critical behavior of a two-dimensional weakly diluted antiferromagnetic Potts model with spin states q = 3 on a triangular lattice is computationally simulated. The...     

Geminal alkylammonium surfactants: Aggregation properties and catalytic activity

Geminal alkylammonium surfactants containing a hexamethylene spacer show a specific behavior, namely, a catalytic effect at low concentrations of the detergent in the system. The critical micellization concentrations of these surfactants are by an order of magnitude lower than those of the related surfactants with one hydrophobic fragment. The effect exerted on the hydrolysis of carboxylic acid esters by micellar structural rearrangements induced by addition of a supporting electrolyte is determined.