Simple diffuse reflectance UV-vis spectroscopic determination of organic pigments (fringelites) in fossils

To screen for organic pigments, like fringelites or porphyrins, in sediments and fossil specimen, a simple diffuse reflectance UV-vis spectroscopic determination was developed. In contrast to common inorganic pigments, like Fe₂O₃, these pigments exhibit well-structured characteristic absorption peaks which allow their recognition. This method was then used to identify fringelite H in a non-crinoidSolenopora species from the Jurassic. Reflectance FTIR spectroscopy proved not to be useful for this purpose.     

Protein identification platform utilizing micro dispensing technology interfaced to matrix-assisted laser desorption ionization time-of-flight mass spectrometry

An integrated protein microcharacterization/identification platform has been developed. The system has been designed to allow a high flexibility in order to tackle challenging analytical problems. The platform comprises a cooled microautosampler, an integrated system for microcolumn HPLC, and a capillary reversed-phase column that is interfaced to matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) system via a low internal volume flow-through microdispenser. The chromatographic separation is continuously transferred onto a MALDI target plate as discrete spots as the dispenser ejects bursts of droplets of the column effluent in a precise array pattern. A refrigerated microfraction collector was coupled to the outlet of the flow-through microdispenser enabling enrichment and re-analysis of interesting fractions. The use of target plates pre-coated with matrix simplified and increased the robustness of the system. By including a separation step prior to the MALDI-TOF-MS analysis and hereby minimizing suppression effects allowed us to obtain higher sequence coverage of proteins compared to conventional MALDI sample preparation methodology. Additionally, synthetic peptides corresponding to autophosphorylated forms of the tryptic fragment 485-496 (ALGADDSYYTAR) of tyrosine kinase ZAP-70 were identified at sensitivities reaching 150 amol.     

Biotinylation: A nonradioactive method for the identification of cell surface antigens in immunoprecipitates

A nonradioactive method was employed to detect different cell membrane antigens on human polymorphonuclear granulocytes, monocytes and platelets. We compared the reactivity of one monoclonal antibody, N1III10, assumed to be FcγRII-specific by functional assays, with other well-characterized monoclonal antibodies and human sera. Intact cells were incubated with biotin N-hydroxysulfosuccinimide ester which preferentially reacts with lysine residues in polypeptides. Biotin-labeled cells were lysed and the antigen was isolated from the cell lysate by immunoprecipitation with the antibody bound to Protein A-Sepharose. The precipitates were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred onto nitrocellulose membrane, and visualized by a streptavidin-alkaline phosphatase system with a suitable substrate. Using this biotin-labeling system we could show that N1III10 detects a 40 kDa antigen on monocytes and platelets, comparable to that expected of FcγRII monoclonal antibodies.     

Effect of halides and alkali cations on the Zn(Hg)/Zn(II) electrode reactions

The title subject has been studied by galvanostatic single-pulse, chronopotentiometric and equilibrium measurements on the Zn(Hg)/Zn(II) electrode in x M KI+(1?x) M KCl (x from 0 to 1), 1 M KBr and 1 M MeCl (Me=Li, Na, K and Cs) solutions of pH 3 at 25°C. Quantitative information about the effect of specifically adsorbed halides on the rates of the Zn(II)/Zn(I) and the Zn(I)/Zn(Hg) steps is obtained separately (for the latter step mainly at potentials near ?1.0 V(SCE)), and the latter step seems to be more influenced than the former by the adsorption. An attempt is made to correlate the adsorption effect on the rate of the Zn(II)/Zn(I) step to double-layer parameters according to recent models for such effects. The extra current observed at potentials where the halides are adsorbed, seems to vary with the surface activity of the specifically adsorbed ion. The lack of any observed kinetic effect of Cs⁺, which is specifically adsorbed at these potentials, is possibly due to the Cs⁺ specific adsorption enhancing the Cl^? specific adsorption and vice versa, so that the decelerating and accelerating effects by these ions may cancel each other.     

The level structure of92Ru up to high spin values

The level structure of⁹²Ru has been studied by means of γ-ray spectroscopy. The nucleus was produced by the⁵⁸Ni(⁴⁰Ca, α2p)⁹²Ru reaction at beam energies of 147 and 187 MeV. The NORDBALL detector system including particle selection was used. A large number of new levels with excitation energies up to 11.3 MeV and spin values up to 22 or 23 units of angular momentum have been established. The level scheme is compared with recent shell model calculations using¹⁰⁰Sn as a core. Some systematics of the g ₉ ^2/?2 configuration is discussed and a strong correlation between the levels in⁹⁰Mo and⁹²Ru is found.