Gas-phase conversion of the U(VI), Sr,Mo, and Zr compounds in nitrating atmosphere

The gas-phase conversion of U₃O₈, MoO₃, SrO, and their mechanical mixtures, and also of ZrO₂ into water-soluble compounds in the atmosphere of (NO _x  + vapor H₂O) or HNO₃ (vapor) was studied. In the course of gas-phase conversion, U₃O₈ and SrO transform into water-soluble compounds (nitrates, hydroxonitrates), whereas MoO₃ and ZrO₂ undergo no changes. The principal possibility of separating U from Mo and Zr by gas-phase conversion of the oxides in the atmosphere of (NO _x  + vapor H₂O) or HNO₃ (vapor) was demonstrated.     

The Carpet-3 experiment to search for diffuse gamma rays with energies of more than 100 TeV

An experiment for measuring the flux of cosmic diffuse gamma rays with energies above 100 TeV (the Carpet-3 air shower array) is now being prepared at the Baksan Neutrino Observatory, Institute for Nuclear Research, Russian Academy of Sciences. The preparations entail a substantial increase of the areas of both the muon detector and the surface air shower array. The experiment’s sensitivity to showers generated by primary gamma rays is estimated for different configurations of the array. In addition, preliminary estimates of the upper limit on the flux of diffuse gamma rays with energies higher than 1.3 PeV, derived using experimental data from the old Carpet-2 array, are presented for a net exposure time of 9.2 years.     

Carpet-2 Search for PeV Gamma Rays Associated with IceCube High-Energy Neutrino Events

JETP Letters - Carpet-2 is an air-shower array at Baksan Valley, Russia, equipped with a large-area (175 m2) muon detector, which makes it possible to separate primary photons from hadrons. We...     

Surface modification of cellulose-containing materials with solutions of tetrafluoroethylene telomers

Russian Journal of Applied Chemistry - Modification of cellulose-containing materials (wood veneer, paper) with solutions of radiationsynthesized tetrafluoroethylene telomers was studied. Treatment...     

Synthesis, structure, and biological activity of mixed-ligand platinum(II) complexes with aminonitroxides

Mixed-ligand platinum complexescis-Pt^II(R⁶NH₂)(NH₃)X₂ andcis-Pt^II(R⁵NH₂)(NH₃)X₂ (R⁶ is 2,2,6,6-tetramethyl-4-piperidyl-1-oxyl and R⁵ is 2,2,5,5-tetramethyl-3-pyrrolidinyl-1-oxyl) were synthesized by either the reaction of aminonitroxides RNH₂ with Na[Pt^II(NH₃)Cl₂I] generatedin situ (for X₂=ClI) or by replacement of the iodo-chloro ligands incis-Pt¹¹(RNH₂)(NH₃)ClI by dichloro and oxalato ligands. The complexes obtained were characterized by elemental analysis and by IR, UV, and ESR spectra. Forcis-Pt¹¹(R⁵NH₂)(NH₃)Cl₂, crystal and molecular structures were determined by X-ray diffraction analysis. Cisplatin accelerates autooxidation of methyl linoleate and the platinum nitroxide complexes synthesized exhibit antioxidant properties. The rate of isolated DNA binding with the new complexes is almost as high as that for cisplatin.cis-Pt¹¹(R⁶NH₂)(NH₃)Cl₂ exhibits the highest antitumor activity. The high antitumor activity of platinum nitroxide complexes shows that the possible “radical component” is not a crucial factor in the cytotoxic action of cisplatin. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1624–1630, September, 2000.     

Interaction of Palladium(II) Acido Complexes with DNA

Interaction of K₂[PdCl₄] (I) and (C₅H₁₂NO)₂[PdCl₄] (II) with DNA in vitro is studied. No fragmentation of DNA occurs under the action of II. The interstrand cross-links are formed due to the formation of complexes with purine and pyrimidine bases; no interaction with DNA phosphates is observed. The cation does not play an essential role in the formation of cross-links.     

Rate and equilibrium constants for the epimerization of the endothelin receptor antagonist J-104,132 in aqueous solution

The degradation of [5S-[5alpha,6beta,7alpha(R*)]]-2-butyl-5-(1,3-benzodioxol-5-yl)-7-[(2-carboxypropyl)-4-methoxyphenyl]-6-dihydro-5H-cyclopenta[b]pyridine-6-carboxylic acid (J-104,132) was studied in aqueous solution as a function of temperature and pH. The degradation reaction does not proceed to completion; rather, a stable equilibrium is attained in which approximately 2% of the degradate is produced. Kinetic data for the formation of the degradate are analyzed using an integrated form of the rate law for a reversible first-order reaction, and the forward and reverse rate constants and overall equilibrium constants are presented. Isolation and spectroscopic structural determination indicate that the degradate is the C7 beta-epimer of the drug. A mechanism for the epimerization reaction involving a novel enamine-like intermediate is proposed and shown to be consistent with the kinetic data. The rate and equilibrium constants are used to predict the room temperature stability of an injectable formulation of J-104,132, and these predictions are compared to actual data from long-term stability studies. It is concluded that the preformulation kinetic studies provide essential data needed for optimum drug product development.