Application of the laser microprobe mass analyzer (LAMMA) to qualitative and quantitative single cell analysis

The laser microprobe mass analyzer (LAMMA ) is a new type of analytical instrument. It is a combination of a laser microscope with a time-of-flight (TOF ) mass spectrometer. By focusing an UV pulse laser beam onto the specimen positive and negative atomic and molecular ions are formed which are detected by the TOF mass analyzer. The detection limits reach 10^–20 g for some elements in an excited sample volume of 10^–13 cm³. With the aim of finding out whether the LAMMA instrument is capable of quantitative measurements on very small biological samples the ²³Na⁺ and ³⁹K⁺ contents of single mycobacterial cells (M. tuberculosis H 37 Ra) were measured and the results were compared with those obtained from “integral” methods (AAS, NAA , tracer). Furthermore, the influence of different temperatures applied during the washing procedure of the bacteria on the distribution of the Na⁺/K⁺ ratio within the cell population was investigated. First attempts to trace isonicotinic acid hydrazide (INH) in bacteria were made by comparison of the LAMMA spectra of INH treated and untreated cells.     

Stratifizierung im Hilbertschema II: Flächen mit gewöhnlichen Singularitäten

Ohne Zusammenfassung     

Das Verhalten von Mono- und Diorganylphosphansulfiden gegenüber Metallcarbonylsystemen. VIII [1]; Die Kristall- und Molekülstruktur von Pentacarbonyl(dimethylmercaptophosphan)-chrom

Inhaltsübersicht. Die S-verknüpfte Verbindung (OC)₃CrSPH(CH₃)₂ isomerisiert sich oberhalb 25°C zu dem Mercaptophosphan-Komplex (OC)₅CrP(CH₃)₂SH. Dieser kristallisiert monoklin in der Raumgruppe P2₁/c mit den Citterkonstanten a = 6,882, b = 13,290, c = 13,224 Å, β = 91,60° und vier Molekeln in der Elementarzelle. In der Kristallstruktur (R = 0,085) sind die Chromatome pseudooktaedrisch koordiniert von fünf CO-Gruppen und dem Mercaptophosphanliganden (Cr—P = 2,344 Å). The Behaviour of Mono- and Diorganylphosphane Sulphides towards Metal Carbonyl Systems. VIII. Crystal and Molecular Structure of Pentacarbonyl(dimethylmereaptophosphane) chromium Abstract. The S-linked compound (OC)₅CrSPH(CH₃)₂ isomerizes to the mercaptophosphane complex (OC)₅CrP(CH₃)₂SH above 25°C. The latter crystallizes monoclinic in the space group P2₁/c with the lattice constants a = 6.882, b = 13.290, c = 13.224 Å, β = 91.60° and four molecules per unit cell. In the crystal structure (R = 0.085) the chromium atoms are pseudooctahedrally coordinated by five CO groups and the mercaptophosphane ligand (Cr—P) = 2.344 Å).     

Absorptionsquerschnitte und Transmissionskoeffizienten für Protonen und Neutronen nach dem optischen Modell

T _l -values and absorption cross sections for protons and neutrons are calculated with optical potentials, which have been fitted to experimental scattering data. Values are given forZ=10, 20, 30, 50, 70, 90, and energies between 0.1 und 25 MeV. For protons we used the local optical potential ofPerey and for neutrons the nonlocal optical potential ofPerey andBuck. The results are compared with those of other optical potentials. In addition it is shown, that the spin-orbit-interaction leads toT _{l j} -values which sometimes differ appreciably depending whetherj equalsl+1/2 orl?1/2.