Determination of sub-nanogram quantities of ruthenium by flameless atomic absorption spectrometry

Flameless atomic absorption spectrometry has been applied to the determination of subnanogram quantities of ruthenium in a variety of matrices encountered in the solidification of nuclear waste. Detection limits ranged to below 10^?10 g, depending on the sample matrix. Most matrix effects could be eliminated by proper selection of atomizer temperature program, allowing the use of a single set of standards in 0.1 N HCl. The one exception was the calcined solid matrix, where a fusion and extraction were used to dissolve the ruthenium and separate it from matrix constituents.     

Charge localization by molecular orbital calculations. II. Formamide,thioformamide and N-methylated analogues

Ab initio molecular orbital calculations have been used to determine the degree of charge localization associated with the formation of radical cations on electron impact of formamide, thioformamide and their N-methyl and N, N-dimethyl analogues. The charge favours the nitrogen of formamides and the sulphur of thioformamides, but the degree of localization is calculated to be lower than in the radical cations of urea and thiourea.     

Influence of deformation upon domain wall pinning defect spectrum in 50-50 NiFe

A measurement of the distribution function of magnetically active defects in 50-50% Ni-Fe was made before and after mild mechanical deformation (? ? 10^?3). After deformation, the distribution function has two maxima instead of the usual one. The results are interpreted in terms of interactions of magnetic domain walls with grain boundaries which, as a result of the deformation, apparently provide more effective pinning sites.     

Conjugate addition of organolithium reagents to acrylanilide anions

Phenyllithium, $\text{n}$-butyllithium, and $\text{t}$-butyllithium were found to add to substituted acrylanilide anions to give the 1,4-addition products in fair to good yields.     

Comparison of fuzzy sets on the same decision space

Some methods of making fuzzy decisions include a comparison of fuzzy sets on the same space. Methods have been published which suffer from lack of discrimination between alternatives and occasional conflict with intuitive choice. These methods are reviewed in this paper and then a new approach is described which overcomes their drawbacks. Methods of evaluating the parameter used in decision-making are given which can be varied to incorporate different utility functions.     

An Azulenic Bacteriorhodopsin Analog Has Photoinduced Activity

Abstract— The photoinduced changes of absorbance as well as proton release and uptake have been observed for an azulenic analog of wild-type bacteriorhodopsin. The release and uptake of protons have been measured using a highly sensitive electrochemical technique. Bacteriorhodopsin membrane patches on a tin-oxide electrode produce a transient photocurrent that is negative for proton release and positive for proton uptake. For azulenic bacteriorhodopsin the photocurrent is approximately 20% of the transient observed with native bacteriorhodopsin. The existence of the photoinduced absorbance changes and the transient photocurrent are important results for gaining further insight into the photoinduced function of bacteriorhodopsin.     

Electrochemistry and chromatographic detection of monosaccharides,disaccharides, and related compounds at an electrocatalytic chemically modified electrode

Many carbohydrate compounds undergo electro-oxidation at modest positive potentials at chemically modified electrodes (CMEs) made by adding cobalt phthalocyanine (CoPC) electrocatalyst to a conventional carbon paste mixture. The active carbohydrates which were oxidized at the CME at +0.4 to 0.5 V vs. Ag/AgCl under the very basic pH conditions required, included not only monosaccharides but also oligosaccharides, deoxy sugars, and even simple polyalcohols such as glycerol. When used for carbohydrate detection after liquid chromatography, the CoPC CME yielded detection limits in the 10–50 pmol range. Electrode stability and selectivity was such that no sample preparation other than dilution and particulate filtration was required for carbohydrate determinations in sample matrices including food products and physiological fluids.