Transmission electron microscopic studies on CS2 hydrolase provide direct evidence for the existence of the hexadecameric catenane and octameric ring topologies. Reconstructions of both protein assemblies are in good agreement with crystallographic analyses of the catenane and ring forms of CS2 hydrolase.

Instruments for microanalysis are now able to provide several images of the same specimen area. In this paper, two groups of methods are described for handling these multivariate maps. One group concerns dimensionality reduction, i.e., the projection of N-dimensional data sets onto a M-dimensional parameter space (M<N). It is shown that, in addition to linear mapping which can be performed by M...

Multicomponent condensation of 1-naphthol, malononitrile, and arylglyoxals in the presence of Mg-Al hydrotalcite under solvent-free MicroWave (MW) conditions gave a new series of 2-amino-4-aroyl-4H-benzo[h]chromene-3-carbonitriles in high yields (70-89%). The structure of all products was elucidated by their...

Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays f...

The basic principle and the properties of threshold spectroscopies in surface analysis are presented. Comparisons are made to Auger microscopy and the prospects for la tera l resolution are discussed.

Abstract Laser induced breakdown spectroscopy is a fast non-contact technique for the analysis of the elemental composition of any sample. Our focus is to advance this technique into a new regime where we use pulse energies below 100 μJ. This regime is referred to as microLIBS or μLIBS. Preliminary pulse emission scaling of Na in latent fingerprints has been investigated for ∼ 130 fs, 266 nm pu...

Quantitative X-ray microanalysis requires the use of many fundamental constants related to the interaction of the electron beam with the sample. The current state of our knowledge of such constants in the particular areas of electron stopping power, X-ray ionization cross-sections, X-ray fluorescence yield, and the electron backscattering yield, is examined. It is found that, in every case, the...

Bromine has been added to cis,trans,trans-1,5,9-cyclododecatriene under various reaction conditions. All expected direct addition products have been isolated, and their structures have been determined by microanalysis, NMR and X-ray crystallography. Advanced NMR techniques were used to determine solution conformations of several of the compounds, enabling comparison with the solid-state conform...