Sound radiation from a joint of plates of different thickness

A method of solving the problem of sound radiation from a plate with elements of different thickness in its plane is proposed, and the results obtained with this method are presented. It is shown that the main sources of sound radiation are the inhomogeneous flexural fields formed in the elements on both sides of their joint.     

Destruction and stabilization of the electromagnetic transparency of a semiconductor superlattice

Three types of transparency of a semiconductor superlattice, namely, self-induced, induced, and selective transparency, were studied. The conditions of their existence and the causes of their destruction were revealed. It was shown that the state of self-induced transparency, which is unstable in a harmonic field, can be stable in a biharmonic field.     

Creation of a donor-acceptor pair for studying intraprotein electron transfer with the participation of amino-acid derivatives of fullerene C60

Efficient quenching of eosin phosphorescence by amino-acid derivatives of fullerene (AADFs) such as C₆₀-alanine and C₆₀-glycine in aqueous solutions indicates the possibility of transferring electrons from eosin to fullerene upon collisions or in the exciplex state. To investigate electron transfer in the protein structure, we studied the process of incorporation of C₆₀-alanine and C₆₀-glycine into the heme pocket of myoglobin by controlling Förster quenching. The dissociation constant for the protein-AADF complex was estimated.     

1,3-diallyl-5-[ω-(diphenylphosphino)alkyl] isocyanurates in reactions of complex formation with palladium(ii) dichloride

The reactions of phosphine derivatives of diallyl isocyanurates with palladium(ii) dichloride lead to the formation of complexes, whose structure, composition, and stability depend on the length of the methylene chain between the isocyanurate and diphenylphosphine fragments in the ligand. 1,3-Diallyl-5-[5′-(diphenylphosphino)pentyl and 10′-(diphenyl-phosphino)decyl] isocyanurates with PdCl₂ form monomeric L₂PdCl₂ trans-complexes in which P atoms of the ligands participate in coordination with the metal. 1,3-Diallyl-5-[2′-(diphenylphosphino)ethyl] isocyanurate with PdCl₂ forms a dimeric (LPdCl₂)₂ complex, which decomposes in a solution to the monomer including solvent molecule into the coordination sphere of the metal. The reactions of 1,3-diallyl-5-[4′-(diphenylphosphino)butyl] isocyanurate and 1,3-diallyl-5-[6′-(diphenylphosphino)hexyl] isocyanurate with PdCl₂ give monomeric chelate LPdCl₂ complexes in which one of the allyl groups of the isocyanurate cycle participates in coordination with the central ion along with the phosphorus atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1859–1865, September, 1998.     

Preparation and Ion-Exchange Properties of Mixed Zirconium(IV) Phosphate-Phosphonate Sorbents

Composite sorbents based on Zr(IV) phosphate-hydroxyethylidenediphosphonate with different phosphate-phosphonate ratio were prepared. These sorbents were characterized by elemental analysis, X-ray diffraction, and IR spectroscopy, and their ion-exchange sorption capacity for several transition metals and strontium was studied. The sorption capacity of these sorbents increases with increasing pH.     

Synthesis and spatial structure of the geometrical isomers of 4-substituted 1-tert-butyl-3-methyl-piperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines

In order to study the interrelationship between the structure, reactivity, and spectroscopic characteristics of the stereoisomeric piperidines, starting from 1-tert-butyl-3-methylpiperidin-4-one the synthesis has been performed of the geometric isomers of some 4-substituted 1-tert-butyl-3-methylpiperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines. The spatial structures of the compounds obtained have been determined by IR and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1056–1061, August, 1973.     

Chemische synthese von nonadesoxyribonucleotiden mit den abgewandelten basen uracil, 5-bromuracil und 5-methylcytosin nach dem triester-verfahren

In order to investigate the interaction of Eco RII restriction and modification enzymes with synthetic DNA fragments three nonadeoxyribonucleotides containing the modified bases uracil, 5-bromouracil and 5-methylcytosine were synthesized according to the phosphate tri-ester approach using TPS/l-methylimidazole as the condensation agent. The patterns of these modified DNA fragments obtained by Maxam/Gilbert sequence technique are presented.     

Anode volt-amperometry of aminopyridines and aminopicolines

The electrochemical behavior of amino derivatives of pyridine — 2-, 3-, and 4-aminopyridines, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 4-amino-3-methylpyridine, and 2,6-diaminopyridine — during their oxidation on a rotating platinum microanode in acetonitrile and aqueous alcohol was investigated. Differences associated with the electronic effect of the substituent were uncovered during the electrical oxidation of the indicated compounds. The data obtained make it possible to conclude that the magnitude of the current strength in the oxidation of aminopyridines is determined by the rate of diffusion of the depolarizer to the electrode.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1654–1657, December, 1977.     

5′-Phosphouridine as a source of terminal phosphate groups in oligonucleotides

A universal key component is proposed for the preparation of oligonucleotides with 3′- and 5′-terminal phosphate groups — 2′,3′-dibenzoyluridin-5′-yl (4-chlorophenylphosphate) (pU(Bz)₂), which is a potential source of the phosphate group. The condensation ofpU(Bz)₂ with the 5′-OH or the 3′-OH group of a protected oligonucleotide leads to the formation of oligodeoxyribonucleotides with 5′- or 3′-terminal uridine, respectively. The oxidation of the 2′,3′-cis-glycol group of the terminal uridine unit followed by β-elimination forms oligodeoxyribonucleotides with terminal phosphate groups.