Rapid chemical separation procedures

Fast, discontinuous separation procedures are described for zirconium, niobium, technetium and antimony from fission products. Other rapid separation methods from aqueous solutions are summarized. The combination of a gas jet recoil transport system with a continuous solvent extraction technique and with a thermochromatographic separation method is presented. The application of such procedures to the investigation of new and already known short-lived nuclides is illustrated by some examples.     

Multielement determination in tobacco leaves by photon activation analysis

A nondestructive photon activation procedure with 30 MeV bremsstrahlung followed by high-resolution gamma-spectrometry has been applied to the multielement determination in tobacco leaves and commercial cigarettes. The elements determined by this method included essential minor elements such as Ca, Cl, K and Mg, essential trace elements such as Fe, Mn and Zn, and possibly toxic elements such As and Sb. The NBS Orchard Leaves could successfully be used as a comparative standard. The method is quite simple and gives good reproducible results for at least 12 elements.     

Complexation of Cu(II) with <Emphasis Type="SmallCaps">L</Emphasis>- and <Emphasis Type="SmallCaps">DL</Emphasis>-threonine: An ESR study

Complexation of Cu(II) ions with L- and DL-threonine in aqueous solution was studied. Treatment of the ESR spectra of solutions containing Cu(II) and threonine in various ratios and having various pH, involving total line shape analysis, revealed formation of geometric isomers of the complex ions [Cu(thrH_–1)₂]^2– differing in the mutual arrangement of the N and O atoms in the equatorial plane; the complexation and isomerization equilibrium constants were determined.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 8, 2004, pp. 1388–1391.Original Russian Text Copyright © 2004 by Statsenko, Bolotin, Panyushkin.This revised version was published online in April 2005 with a corrected cover date.     

Characterization of dynamic and steady-state protein phosphorylation using a fluorescent phosphoprotein gel stain and mass spectrometry

Protein phosphorylation plays a vital role in the regulation of most aspects of cellular activity, being key to propagating messages within signal transduction pathways and to modulating protein function. Pro-Q Diamond phosphoprotein gel stain is suitable for the fluorescence detection of phosphoserine-, phosphothreonine-, and phosphotyrosine-containing proteins directly in sodium dodecyl sulfate (SDS)-polyacrylamide gels. The technology is especially appropriate for profiling steady-state and dynamic phosphorylation on a proteome-wide scale, as demonstrated through detection of the native phosphorylation of cardiac mitochondrial phosphoproteins and changes in this profile arising from the activity of a protein kinase. For example, Pro-Q Diamond phosphoprotein gel stain was employed to demonstrate that among the 46 subunits of the mitochondrial respiratory chain complex, NADH:ubiquinone oxidoreductase (complex I), a 42 kDa subunit is phosphorylated in the steady-state. However, exposure of mitochondria to cAMP-dependent protein kinase increases phosphorylation of this 42 kDa subunit and results in de novo phosphorylation of an 18 kDa subunit as well. Since Pro-Q Diamond dye binds to phosphorylated residues noncovalently, the staining technology is fully compatible with modern microchemical analysis procedures, such as peptide mass profiling by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry and post-source decay analysis of peptide phosphorylation.     

A Simple Method for Determining the Enthalpy of Specific Solute-Solvent Interaction

An equation correlating a parameter that described the enthalpy of nonspecific solvation of nonelectrolytes with a quantity characterizing intermolecular solute-solvent interaction was found. A simple and versatile method based on this equation was suggested for calculating the enthalpy of nonspecific solvation and the enthalpy of specific solute-solvent interaction.     

Determination of mono-, di- and polyamines in foods using a single-column amino acid auto-analyzer

A fully automated, rapid and sensitive method was developed to analyze fourteen different biogenic amines in food. Using a Technicon C4 ion-exchange resin column (20 m X 0.5 cm), adapted to an automatic Technicon TSM amino acid analyzer, the following amines were separated and quantified: adrenaline, noradrenaline, 1,3-diaminopropane, putrescine, cadaverine, histamine, spermidine, dopamine, spermine, agmatine, tyramine, serotonin, phenethylamine and tryptamine. Five buffers were required to elute the amines using a gradient of pH from 5.6 to 12.7; the column temperature was maintained at 65 degrees C. The method was also assayed on ground beef, cheese and wine samples. Amines from cheese and ground beef samples were extracted with 0.6 M perchloric acid. No extraction of wine samples was necessary.     

Telomerization of ethylene with 1,1,1,3-tetrachloropropane in the presence of iron pentacarbonyl and isopropyl alcohol

Conclusions Polychlorinated hydrocarbons containing the CCl₃ group can be used as telogens in the telomerization of olefins in the presence of iron pentacarbonyl and i-C₃H₇OH. The formation of the telomer homologs in high yield obeys the general rules that were established for the given initiating system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2837–2839, December, 1971.     

π-Electron hyperconjugation in organic molecules and ions

The extent of energetic stabilization by alkyl groups with -electron systems via hyperconjugation is investigated theoretically by MINDO molecular orbital calculations. In neutral hydrocarbons, this stabilization represents about 4 % of the effective C-C bond energy, and is additive in the number of alkyl groups present. Calculations for conjugated, polar, and ionic molecules are also discussed.

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Zusammenfassung Das Ausma\ der energetischen Stabilisierung von -Elektronen-Systemen mit Alkylgruppen durch Hyperkonjugation wird theoretisch durch MINDO-MO-Berechnungen untersucht. In neutralen Kohlenwasserstoffen betrÄgt diese Stabilisierung etwa 4% der effektiven C-C Bindungsenergie und ist additiv entsprechend der Zahl der vorhandenen Alkylgruppen. Berechnungen für konjugierte, polare und ionische Moleküle werden ebenfalls diskutiert.

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Résumé La méthode des orbitales moléculaires MINDO est utilisée pour calculer le degré de stabilisation par hyperconjugaison entre des groupements alkyles et des systèmes d'électrons . Dans des hydrocarbures neutres cette stabilisation représente environ 4% de l'énergie effective de la liason C-C; elle est additive par rapport au nombre de groupements alkyles. On discute aussi des calculs effectués pour des molécules conjuguées polaires ou ioniques.

     

Studies in the benzazole and naphthazole series. VIII. Reaction of 2-hydrazinonaphth[1, 2-d]imidazole and its 1- and 3-methyl derivatives with carbon disulfide

When heated with carbon disulfide in pyridine 2-hydrazinonaphth[1, 2-d]imidazole yields S-triazolo[4, 3-b]-naphth[1, 2-d]imidazole-3-thione. Kinetic and not steric factors determine the formation of this compound. Its trans-angular structure is demonstrated by the agreement between its UV spectrum and that of 11-methyl-S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, prepared from 1-methyl-2-hydrazinonaphth[1, 2-d]imidazole and carbon disulfide, as well as by the identity of their methylation products. Methyl iodide methylation, in the presence of sodium methoxide, of S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, like that of S-triazolo[4, 3-a]benzimidazole-3-thione, takes place stepwise. First the methyl group adds to the nitrogen atom of the imidazole ring, and only then to the thiol group of the triazole ring.For Part VII see [3].