Multidimensional Watson lemma and its applications

We prove the multidimensional analog of the well-knownWatson lemma and then apply it to prove a local limit theorem for the transition probabilities of symmetric random walks on the multidimensional lattice with infinite variance of jumps.     

Fabrication of polytetrafluoroethylene- and graphite-containing oxide layers on aluminum and titanium and their structure

Stable aqueous electrolyte emulsions with negatively charged micelles containing dispersed particles of polytetrafluoroethylene (PTFE) or graphite are obtained using siloxane-acrylate emulsion as an emulsifier. The oxide coatings formed in such electrolytes contain carbon, polytetrafluoroethylene, or graphite. The coatings with PTFE particles are similar to monolithic polytetrafluoroethylene with respect to its hydrophobic characteristics. According to X-ray photoelectron spectroscopy data, the surface of the formed coatings predominantly contains aliphatic carbon (C-C and C-H bonds) and some fraction of oxidized (or, in the case of PTFE-containing electrolytes, fluorinated) carbon.     

Transformations of 6,7-Epoxy Derivatives of Citral and Citronellal in Various Acidic Media

The transformations of 6,7-epoxy derivatives of widely spread in the nature unsaturated aldehydes, citral and citronellal, in various acidic media both under conditions of homogeneous and heterogeneous catalysis were investigated. A number of previously unknown products belonging to different classes of organic compounds was obtained. Probable mechanisms of the products formation are discussed.     

Influence of solid surface on the compatibility in polymer blends produced in situ

Blends of linear polyurethane and poly(methyl methacrylate) were obtained in situ in the course of simultaneously proceeding reactions of polymerization and polyaddition. The effect of filler nanoparticles on the thermodynamic properties of the systems was investigated. Introduction of filler into the monomer mixture before curing increases the compatibility of final systems, as follows from diminishing thermodynamic interaction parameters. The reverse correlation has been established between the interaction parameter and the fraction of an interfacial region between two phases, its origin being the result of incomplete phase separation. Introducing filler into the reaction system determines simultaneously the increasing compatibility and increasing fraction of an interfacial region, i.e., prevents phase separation. Both effects are due to increasing of the interaction between two polymeric components at the interface with solid and changing conditions of incomplete phase separation in the course of reaction.     

Reactions of caryophyllene,isocaryophyllene, and their epoxy derivatives with acetonitrile under ritter reaction conditions

Acid-catalyzed reactions between acetonitrile and caryophyllene, isocaryophyllene, caryophyllene 4, 5-epoxide, and isocaryophyllene 4,5-epoxide affording optically active amides with a tricyclic skeleton were investigated.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 11, 2004, pp. 1641–1646.Original Russian Text Copyright © 2004 by Yarovaya, Korchagina, Rybalova, Gatilov, Polovinka, Barkhash.     

Synthesis and Antiviral Activity of N-Heterocyclic Hydrazine Derivatives of Camphor and Fenchone

Chemistry of Heterocyclic Compounds - Alkylation of the primary amino group of hydrazones of (+)-camphor and (–)-fenchone with dihaloalkanes leading to the production of novel...     

Peculiarities of formation of optically transparent photocurable compound adhesive with high refractive index

The peculiarities of the formation of an optically transparent, photocurable composition with a high refractive index based on epoxy resin are studied. The optimal ratios of the components at which the fastest and most complete formation of three-dimensional structures occurs are established.     

Anodic oxidation of complex shaped items of aluminum and aluminum alloys with subsequent electrodeposition of copper coatings

It was shown that the method of anodization of aluminum and aluminum alloys can be applied for subsequent plating of highly adherent copper coating instead of the known zincate treatment with additional annealing. Fluorine-containing additives in anodizing electrolyte were proposed as activator of oxide film. The parameters of the anodic film (thickness, porosity, and microroughness) were calculated. The plated quality copper coatings have high adhesion to the aluminum support, and no additional heat treatment is required. This considerably reduces the processing time for deposition of multilayer coatings and decreases the material costs.     

Synthesis and In Vitro Study of Antiviral Activity of Glycyrrhizin Nicotinate Derivatives against HIV-1 Pseudoviruses and SARS-CoV-2 Viruses

When developing drugs against SARS-CoV-2, it is important to consider the characteristics of patients with different co-morbidities. People infected with HIV-1 are a particularly vulnerable group, as they may be at a higher risk than the general population of contracting COVID-19 with clinical complications. For such patients, drugs with a broad spectrum of antiviral activity are of paramount importance. Glycyrrhizinic acid (Glyc) and its derivatives are promising biologically active compounds for the development of such broad-spectrum antiviral agents. In this work, derivatives of Glyc obtained by acylation with nicotinic acid were investigated. The resulting preparation, Glycyvir, is a multi-component mixture containing mainly mono-, di-, tri- and tetranicotinates. The composition of Glycyvir was characterized by HPLC-MS/MS and its toxicity assessed in cell culture. Antiviral activity against three strains of SARS-CoV-2 was tested in vitro on Vero E6 cells by MTT assay. Glycyvir was shown to inhibit SARS-CoV-2 replication in vitro (IC₅₀2–8 μM) with an antiviral activity comparable to the control drug Remdesivir. In addition, Glycyvir exhibited marked inhibitory activity against HIV pseudoviruses of subtypes B, A6 and the recombinant form CRF63_02A (IC₅₀ range 3.9–27.5 µM). The time-dependence of Glycyvir inhibitory activity on HIV pseudovirus infection of TZM-bl cells suggested that the compound interfered with virus entry into the target cell. Glycyvir is a promising candidate as an agent with low toxicity and a broad spectrum of antiviral action.     

Acid-catalyzed transformations of diepoxy derivatives of terpinolene

Transformations of diepoxy derivatives of terpinolene under conditions of homogeneous and heterogeneous acid catalysis were studied. Qualitative and quantitative compositions of the reaction mixtures were found to depend on the acidity of the medium and mutual orientation of the epoxide rings in the p-menthane skeleton. The experimental data were compared with the results of computer simulation of the most probable transformation pathways in terms of molecular mechanics and quantum-chemical methods.