Experimental study of the albedo of a beam of γ rays produced by ultrarelativistic electrons

A study has been carried out of the spectral dependence of -radiation scattered from targets irradiated with beams of rays produced by relativistic electrons in crystals. It is shown that the change in the spectral composition of the beam of rays incident on the target changes considerably the spectral properties of the scattered radiation. The spectra of the scattered radiation are studied as a function of the thickness and atomic number of the scatterer. It is shown that the atomic number of the scattering material can be determined from the ratio of the spectral components of the scattered radiation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 106–119, June, 1991.     

Degradation of Copolymers of N-Vinylpyrrolidone with Sodium 2-Acrylamido-2-Methylpropanesulfonate in Aqueous Solutions

The kinetics of controllable degradation of N-vinylpyrrolidone-sodium 2-acrylamido-2-methylpropanesulfonate copolymers in aqueous solutions under the action of degrading agents at 25-50°C were studied by viscometry. The efficiency of controlling the molecular weight of copolymer was estimated.     

Cyclocondensation of 2-Fluoro-5-nitrobenzaldehyde with Amidines. New Synthesis of Isoquinolines

The direction of the cyclocondensation of 2-fluoro-5-nitrobenzaldehyde with five amidines having -hydrogen atoms has been studied. It was established that depending on the structure of the amidine the main products of the reaction may be not only quinazolines but also 3-aminoisoquinolines. A new convenient route has been found for the synthesis of 3-aminoisoquinolines consisting of the cyclocondensation of -acylacetamidines with 2-fluoro-5-nitrobenzaldehyde.     

Methyl alcohol associated-ion formation and decomposition in field ionization

A study has been made on the formation of methyl-alcohol associated ions by field desorption and by quantum-chemical methods (SCF MO LCAO in the CNDO/2 valency approximation). Field desorption can be used to determine molecular interaction characteristics because the electric field has the role merely of ionizing the products.Translated from Teoreticheskaya i Èksperimental'naya Khimiya, Vol. 25, No. 6, pp. 653–659, November–December, 1989.     

Clarification of kaolin suspension and turbid natural water in the presence of Praestols and aluminum sulfate and aluminosilicate coagulants

The kinetics of clarification of a kaolin suspension and turbid natural water in the presence of coagulants (aluminum sulfate and aluminosilicate) and flocculants (nonionic, cationic, and anionic Praestols) was studied in relation to the concentrations of coagulants and flocculants.     

Neodymium(III) tris(1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)propane-1,3-dionato)(1,10-phenanthroline): Synthesis and photophysical properties

The reaction of NdCl₃ with 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)propane-1,3-dione (HL) and 1,10-phenanthroline (Phen) in the presence of a base afforded complex [Nd(L)₃Phen] (I). Unstable solvate I · 2CH₂Cl₂ was obtained from a solution of the complex in dichloromethane, and its structure was determined by X-ray diffraction analysis. The photophysical properties of the complex were studied. Possible routes for the energy transfer in the course of photoluminescence were proposed.     

Synthesis and physicochemical study of hexaamminechromium(III) hexamolybdogallate

Hexaamminechromium(III) hexamolybdogallate of composition [Cr(NH₃)₆][GaMo₆O₁₈(OH)₆] · 5H₂O (I) was synthesized and studied by mass spectrometry, IR spectroscopy, thermogravimetry, and X-ray diffraction. Crystals I are monoclinic: a = 11.77 Å, b = 10.97 Å, c = 15.49 Å, β = 115.11°, V = 1811.29 ų, ρ_calc = 1.17 g/cm³, Z = 1. The compound obtained was used as a catalyst for soft oxidation of natural gas at 633 K.     

Development of a polymer system for the delivery of daunorubicin to tumor cells to overcome drug resistance

Method for the synthesis of polymeric nanoparticles (NP) with encapsulated daunorubicin (DNR) was developed on the basis of double emulsion solvent evaporation technique using biodegradable poly(lactide-co-glycolide) (PLGA), which is aimed at customization of pharmacokinetic properties of the preparation, enhanced accumulation of DNR in tumor cells and prolongation of its action. The obtained polymer nanoparticles (DNR-PLGA) had average size ranging around 138±36 nm, with zeta-potential of –25.3 mV and the polydispersity index (PDI) of 0.072. The release kinetics of DNR from polymer nanoparticles at pH 7.4 and 5.0 has been studied. In vitro studies showed similar specific activity of DNR- PLGA in K562 and MCF-7 cancer cell lines together with an increase in activity in K562 Adr and MCF-7 Adr cell lines, which are anthracycline resistant, by 1.6 and 3.4 times. The study demonstrated the efficacy of the developed PLGA-based DNR delivery system in the improvement of antitumor effect of DNR, overcoming multidrug resistance in cancer cells, and also in the decrease in nonspecific toxicity of the preparation.     

Thermodecomposition ofo-benzoquinone complexes of transition metals

Thermodecomposition of 3,5- and 3,6-di-tert-butyl-o-benzoquinone complexes of Cu, Fe, Co, Cr, Mo, and W has been investigated in the solid phase by the thermogravimetric method. The relative stability of a series of complexes has been determined from the temperatures at which their decomposition begins. Detachment of a neutral electron-donor ligand takes place in the first stage. Detachment of ano-quinone ligand and decomposition of theo-benzoquinone formed occur in the next stage. Thermodecomposition of Fe, Co, Cr, Mo, and W complexes gives oxides or carbides, while copper complexes decompose to pure metal.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 327–329, February, 1994.     

Stereochemical and electronic structure of the free base,cation, and dication of porphin

The equilibrium stereochemical and electronic structure of the free base and the mono- and dications of porphin was calculated by the MO-LCAO SCF method in the CNDO/2 approximation. Successive protonation of the porphin molecule leads to an increase in the dimensions of the conjugation contour and to stage-by-stage exclusion of the nitrogen atoms. It was also established that single and double protonation of the free base does not lead to destruction of the coplanarity of the porphyrin macrocycle.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 3, pp. 339–343, May–June, 1988.