Calculation of transition metal compounds using an extension of the CNDO formalism. V. many body effects in the inner valence shell photoionization spectra of free and coordinated carbon monoxide

The inner valence shell region in the photoionization spectra of NiCO, Ni(CO)₄ and Cr(CO)₆ is studied by means of a diagonal two-particle—hole Tamm—Dancoff approximation. Many body effects are found in the energy range of the CO-ligand ionizations. The effects are more pronounced in NiCO and Ni(CO)₄ than in Cr(CO)₆. Since similar results have to be expected for adsorbate systems, the interpretation of photoemission spectra of such systems on the basis of the simple one particle picture should be handled with care.     

Ein Isomorphiesatz für Potenzreihenräume

Ohne Zusammenfassung     

Low-frequency signal changes reflect differences in functional connectivity between good readers and dyslexics during continuous phoneme mapping

The current fMRI study investigated correlations of low-frequency signal changes in the left inferior frontal gyrus, right inferior frontal gyrus and cerebellum in 13 adult dyslexic and 10 normal readers to examine functional networks associated with these regions. The extent of these networks to regions associated with phonological processing (frontal gyrus, occipital gyrus, angular gyrus, inferior temporal gyrus, fusiform gyrus, supramarginal gyrus and cerebellum) was compared between good and dyslexic readers. Analysis of correlations in low-frequency range showed that regions known to activate during an "on-off" phoneme-mapping task exhibit synchronous signal changes when the task is administered continuously (without any "off" periods). Results showed that three functional networks, which were defined on the basis of documented structural deficits in dyslexics and included regions associated with phonological processing, differed significantly in spatial extent between good readers and dyslexics. The methodological, theoretical and clinical significance of the findings for advancing fMRI research and knowledge of dyslexia are discussed.     

Identification of the rapamycin-sensitive phosphorylation sites within the Ser/Thr-rich domain of the yeast Npr1 protein kinase

The Saccharomyces cerevisae nitrogen permease reactivator Npr1 is a hyperphosphorylated protein that belongs to a fungus-specific family of Ser/Thr protein kinases dedicated to the regulation of plasma membrane transporters. Its activity is regulated by the TOR (target of rapamycin) signalling pathway. Inhibition of the TOR proteins by treating yeast cells with the immunosuppressant drug rapamycin promotes rapid dephosphorylation of Npr1. To identify the rapamycin-sensitive phosphorylation sites in yeast Npr1, glutathione-S-transferase (GST)-tagged Npr1 was isolated from untreated or rapamycin-treated cells, and analyzed by mass spectrometry. Here, we report for the first time 22 phosphorylation sites that are clustered in two regions of the N-terminal serine-rich domain. All phosphorylation sites, except two, were found to be rapamycin-sensitive. Some phosphorylation sites are contained in motifs that closely resemble those in mammalian S6K (serines followed by a tyrosine or a phenylalanine) and 4E-BP1 (serines followed by a proline). Other sites, such as serines followed by Ala, Asn, Gln, His, Ile, Leu, or Val, appear to define new motifs. Thus, TOR controls an unusually broad array of phosphorylation sites in Npr1. In addition to phosphorylation by upstream kinases, Npr1 undergoes autophosphorylation that was mapped to three distinct serines in the N-terminal domain of which Ser257 appears to be the main autophosphorylation site. Site-directed mutagenesis confirmed the mass spectral assignments of the autophosphorylation sites and shows that Ser257 is specifically involved in forming an in vitro substrate-binding site.     

Influence of active sites distribution on CaCO<Subscript>3</Subscript> formation under model biofilms at the air/water interface

In an approach to understand the influence of structural parameters of interfaces on calcification in biomineralisation, the distribution of COOH groups as active sites in an inert matrix was varied using two-component lipid model monolayers. Octadecanoic acid (ODA) and octadecyl succinic acid (OSA), respectively, were the active components, and methyl octadecanoate (MOD) the inactive matrix. Surface pressure-area isotherms provide evidence for a different distribution of the active components in the matrix. Formation of solid calcium carbonate (CaCO₃) with two-component monolayers on subphases containing aqueous CaCO₃ was observed in situ by Brewster angle microscopy, where CaCO₃ domains appear bright. Striking differences in kinetics and extent of CaCO₃ formation were observed between monolayers containing ODA and those containing OSA of the same average surface density of COOH groups.     

Saddle points of index 2 on potential energy surfaces and their role in theoretical reactivity investigations

After a general characterization of second order saddle points two boundary cases are derived and illustrated by examples. The utilization of the classification is pointed out. One type, the virtual saddle point of index 2 (V-SP 2), may be understood as geometrical superposition of two saddles of index 1 (transition structures) which belong to relatively independent processes within the chemical system.     

Zur Reaktion von 4-Alkylaminodihydro-2(1H)-pyridinthionen bzw. -onen mit Ethylmalonsäure-bis-trichlorphenylester

4-Alkylamino-2(1H)-pyridinethiones (1) react with bis-trichlorphenylethylmalonate (3) to give four isomeric products: 5-thioxo-1,6-naphthyridine-2(1H)-ones (4), 7,7-dimethyl-4H-thiopyrano[2,3-b]pyridine-4-ones (6), 2,2-dimethyl-2H-thiopyrano[2,3-b]pyridine-5,7-dioles (7) and 2,2-dimethyl-2H-thiopyrano[2,3-b]pyridine-5(3H)-ones (8). On treatment with alkali the thioxogroup of4 is hydrolyzed and 1,6-naphthyridinediones (5) are formed. Compound5 can also be synthesized by heating the alkylaminopyridones (2) together with3.6 can be hydrolyzed to 2-thioxo-3-pyridylpropylketones (12). On treatment with diluted alkali or conc. acid the aminogroup of7 and8 is hydrolyzed and10 is formed. By heating in 20% NaOH10 is transformed to the dihydroxymercapto-3-pyridylmethylketone (11).

Herrn Prof. Dr.Erich Ziegler mit den besten Wünschen zum 70. Geburtstag gewidmet.