Prediction of Separation Factors Using Group Contribution Methods a Review

For separation process design calculations such as distillation, absorption and extraction it is unconditionally necessary to have quantitative information on the mixtures in consideration, i.e. knowledge about phase equilibrium compositions, heats of mixing etc.     

Infrared Spectra of Tris(ethylendiamine) Cobalt(III) Complex Ion in Solid State and Dissolved in Light and Heavy Water

In recent years, at least two groups^1,2 have developed programmes for combined conformational and vibrational analysis of complicated molecular systems. A version of one of these systems² is currently being adapted for work on coordination complexes. In such work experimental data are needed, and they stem almost exclusively from x-ray structural determinations, and infrared spectra of solids. Most calculational schemes so far deal with isolated molecules, and as one objective of the calculations is to provide thermodynamic functions, which, as far as coordination complexes are concerned, are measured in aqueous solution, we consider it necessary to compare some key properties of the substances as measured in the solid state and in solution. In particular, we want to investi- gate the extent to which internal vibrations are independent of the surroundings of the complexion.     

Profiling of impurities in illicit amphetamine samples by high-performance liquid chromatography using column switching

A simple high-performance liquid chromatographic method, suitable for routine profiling of impurities in illegally produced amphetamine, has been developed. Amphetamine is dissolved in acetonitrile-citrate buffer (pH 3) (2:8) and injected directly without further sample pre-treatment. The impurities are enriched on-line on a C8 extraction column, while amphetamine and polar diluents are washed out with water. After washing for 1.5 min, a six-port valve is switched and an acetonitrile-0.2 M butylamine in water (pH 8) gradient elutes the impurities from the extraction column on to a C18 analytical column where they are separated. The compounds are monitored by UV detection at 220 and 254 nm. The total extraction and analysis time is 30 min. The method allows automated extraction and analysis to be performed.     

Nuclear rotational population patterns in heavy-ion scattering and transfer reactions

A model of²³⁹Pu with decoupled neutron is used for theoretical calculations of rotational population patterns in heavy ion inelastic scattering and one-neutron transfer reactions. The system treated is⁹⁰Zr on²³⁹Pu at the near-barrier energy of 500 MeV and backscattering angles of 180° and 140°. The influence of the complex nuclear optical potential is seen to be very strong, and the Nilsson wave function of the odd neutron produces a distinctive pattern in the transfer reaction.     

Alpha decay theoretical calculations for 125-neutron nuclei

We have applied the new normalized and an older shell-model alpha decay theory to the calculation of decay rates of three 125-neutron isotones²⁰⁹Po,²¹¹Rn, and²¹³Ra. We also have applied the theory to the 2.1-ms isomer of²¹³Ra and are able thus to select a 17/2?assignment as preferable to the 13/2+ alternative.     

The classical-limit S-matrix for Coulomb excitation

An expression for the classical-limit S-matrix for Coulomb excitation is derived and directly evaluated without resorting to stationary phase integration methods. The results obtained are in quantitative agreement with quantum mechanical calculations. This agreement and the simplicity of the method suggest tha feasibility of extending it to cases where other methods are not easily applied.     

Force field modeling of conformational energies: Importance of multipole moments and intramolecular polarization

The ability of force fields to reproduce relative conformational energies for seven molecules is probed. The correlation against LMP2/cc‐pVTZ results for standard force field employing fixed partial charges deteriorates as the molecules become more polar. Inclusion of multipole moments and intramolecular polarization can improve the correlation, and both contributions are of similar importance. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

High temperature gas chromatography of trimethylsilyl derivatives of alcohol ethoxylates and ethoxysulfates

Conversion of ethoxylated alcohols to trimethylsilyl derivatives and subsequent high temperature gas chromatography allowed for the determination of alkyl chain distribution, mole average degree of ethoxylation and weight percent distribution of several commercial mixtures. Repetitive derivatizations and analyses of a mixture with a vendor specified mole average degree of ethoxylation of 3.0 (Neodol 23-3), yielded an experimental result of 2.93 ± 0.05 (n = 6). Mixtures with different alkyl chain distributions and higher degrees of ethoxylation provided similar accuracy. Extension of the method to the analysis of ethoxylated alcohol sulfate raw materials and ethoxylated alcohol sulfates in dishwashing liquids is discussed.     

The human keratinocyte two-dimensional gel protein database (update 1992): towards an integrated approach to the study of cell proliferation, differentiation and skin diseases.

The master two-dimensional gel database of human keratinocytes currently lists 2980 cellular proteins (2098 isoelectric focusing, IEF; and 882 nonequilibrium pH gradient electrophoresis, NEPHGE) many of which correspond to posttranslational modifications. About 20% of all recorded proteins have been identified (protein name, organelle components, etc.) and they are listed in alphabetical order together with their M(r), pI, cellular localization and credit to the investigator(s) that aided in the identification. Also, we have listed 145 microsequenced proteins that are recorded in this database. As an aid in localizing the polypeptides we have included blow-ups of the master images (IEF, NEPHGE) displaying all the protein numbers. In the long run, the master keratinocyte database is expected to link protein and DNA sequencing and mapping information (Human Genome Program) and to provide an integrated picture of the expression levels and properties of the thousands of proteins that orchestrate various keratinocyte functions both in health and disease.