Untersuchungen an Thalliumfluoridometallaten, TIx[SE(III)yFx+3y], der Lanthanoide mit SE = La-Nd, Sm-Lu

Das Ziel dieser Arbeit war es, neue Verbindungen des Typs Tlx[SEyFx+3y] mit den Lanthanoiden als SE auf einfachem, hydrothermalem Wege zu erhalten, zu charakterisieren und auf ihre mögliche Verwendung als Szintillatormaterial hin zu untersuchen. Zum Einen konnten die bislang unbekannten Verbindungen Tl[SE2F7], mit SE = Sm — Dy, er-folgreich synthetisiert werden. Die Darstellung dieser Verbindungen erfolgte hydrothermal im Autoklaven bei Temperaturen bis 210 bzw. 400 °C. Zwar gelang es nicht, Einkristalle zu erhalten und die Struktur auf diesem Wege zu ermitteln, dafür konnten die Verbindungen mittels Röntgenpulverdiffraktometrie, Atomabsorptionsspektrometrie, Ionenchromatogra-phie, dynamischer Differenzkalorimetrie und energiedispersiver Röntgenspektrometrie cha-rakterisiert werden. Anhand der Daten der Röntgenpulverdiffraktometrie konnte auf die Elementarzelle rückgeschlossen werden. Sie kristallisieren isotyp in der Raumgruppe (Nr. 255), mit 2 Formeleinheiten pro Elementarzelle. Zum Anderen wurden die ebenfalls bislang unbekannten Verbindungen Tl3[SEF6], mit SE = Ho — Lu, hergestellt. Die Darstellung der Verbindungen erfolgte im Autoklaven bei Temperaturen bis 400 °C. Es gelang auch im Falle dieser Verbindungsgruppe nicht, Einkristalle zu erhalten. Mittels der oben genannten Analysemethoden sowie mittels DFT-Rechnungen konnte eine Struktur für diese Verbindungen angegeben werden. Sie kristallisie-ren isotyp in einer kubisch innenzentrierten Zelle mit 2 Formeleinheiten pro Elementarzelle. Die Verbindungen wurden zudem auf ihre Fluoreszenzeigenschaften hin untersucht. Dabei zeigte sich, dass drei der Verbindungen, und zwar Tl[Tb2F7], Tl[Dy2F7] und Tl3[ErF6], deutliche Fluoreszenz zeigen. Die gemessenen Werte liegen sowohl bezüglich der Wellenlänge, als auch der Abklingzeiten, vergleichen mit literaturbekannten Stoffen, im Bereich von bekann-ten und anwendungsreichen Referenzen. Diese Eigenschaften könnten beispielsweise durch Doping mit anderen Elementen in tech-nisch bedeutende Bereiche verschoben werden.The aim of this study was to obtain, to characterize and to examine the possible use as a scintillator of new compounds of the type Tlx[SEyFx+3y] with the lanthanides as SE in a simple, hydrothermal method. On the one hand the hitherto unknown compounds Tl[SE2F7], with SE = Sm - Dy, were synthesized successfully. The preparation of these compounds was carried out hydrothermally in an autoclave at temperatures up to 210 or 400 °C. Although it was not possible to obtain single crystals and to determine the structure in this way, but the compounds were characterized by X-ray, atomic absorption spectrometry, ion chromatography, energy dispersive X-ray spectrometry and differential scanning calorimetry. Based on the data of X-ray powder diffraction the unit cells could be inferred. They crystallize isotypically in the space group (no. 255), with 2 formula units per unit cell. On the other hand, the also previously unknown compounds Tl3[SEF6], with SE = Ho - Lu, were synthesized. The preparation of the compounds was carried out in an autoclave at temperatures up to 400 °C. Also in the case of this group of compounds, it was not possible to obtain any single crystals. With the above-mentioned analysis methods and by means of DFT calculations a structure for these compounds could be specified. They crystallize isotype in a body-centered cubic cell with 2 formula units per unit cell. The compounds were also examined for their fluorescence properties. It turned out that three of the compounds, namely Tl[Tb2F7], Tl[Dy2F7] and Tl3[ErF6], show significant fluorescence. The measured values are in terms of both wavelength and the decay, comparing literature materials, ranging from known and application-rich references. These properties could be moved, for example, by doping with other elements in technically significant areas

Verdienen die "Renitenten" eine härtere Gangart? : Hintergründe zur Kooperation in der Sozialhilfe

Die aktuelle sozialstaatliche Praxis beantwortet die provokative Frage im Titel mit Ja. Seit dem 1. Januar 2016 gelten neue SKOS-Richtlinien, welche nebst tieferen Unterstützungsbeiträgen für Grossfamilien und junge Erwachsene auch härtere Sanktionen für unkooperative Klienten vorschlagen. Vor dem Hintergrund der Ergebnisse eines dreijährigen Nationalfonds-Forschungsprojektes zur Kooperation in der Sozialhilfe möchten wir aufzeigen, dass Sanktionen in der Sozialhilfe keine Probleme lösen, sondern welche erschaffen

Lossless State Detection of Single Neutral Atoms

We introduce lossless state detection of trapped neutral atoms based on cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a hyperfine-state-detection fidelity of 99.4% is achieved in 85 microseconds. The quantum bit is interrogated many hundreds of times without loss of the atom while a result is obtained in every readout attempt. The fidelity proves robust against atomic frequency shifts induced by the trapping potential. Our scheme does not require strong coupling between the atom and cavity and can be generalized to other systems with an optically accessible quantum bit.Comment: 4 pages, 4 figure

Endomannosidase undergoes phosphorylation in the Golgi apparatus

Glucose residues from N-linked oligosaccharides are removed by glucosidases I and II in the endoplasmic reticulum (ER) or by the alternate endomannosidase pathway in the Golgi apparatus. Our morphological analysis demonstrates that recombinant rat endomannosidase exhibited a cis- and medial-Golgi localization alike the endogenous enzyme and its ER to Golgi transport is COP II mediated. Recombinant endomannosidase undergoes a posttranslational modification, which is not related to N-or O-glycosylation. A shift in molecular mass of recombinant endomannosidase was observed upon phosphatase digestion but not for ER-retained CHO cell endomannosidase. Furthermore, immunoprecipitation of 35S- and 33P-labeled endomannosidase expressed in CHO-K1 cells suggests that recombinant endomannosidase undergoes phosphorylation. Substitution of the single cytoplasmic threonine residue of rat endomannosidase by either an alanine or valine residue resulted in the same posttranslational modification alike the wild-type enzyme. The subcellular localization and the in vivo activity of the mutant endomannosidase were not affected. Thus, endomannosidase phosphorylation is occurring in luminal sequences. Modification was prevented when endomannosidase was synthesized using reticulocyte lysates in the presence of canine microsomes. Treatment of cells with brefeldin A blocked the posttranslational modification of endomannosidase, suggesting that phosphorylation is occurring in the Golgi apparatus, the residence of endomannosidas

A cell culture system for the induction of Mallory bodies: Mallory bodies and aggresomes represent different types of inclusion bodies

Mallory bodies (MBs) represent keratin-rich inclusion bodies observed in human alcoholic liver disease and in several chronic non-alcoholic liver diseases. The mechanism of their formation and their relationship to other inclusion bodies such as aggresomes is incompletely understood. We could induce keratin aggregates typical of MBs in cultured clone 9 rat hepatocytes by transgenic expression of wild-type and mutant aquaporin2 or α1-antitrypsin and under various forms of other cellular stress. By immunocytochemical analysis, p62 and poly-ubiquitin, components of classical MBs, could be demonstrated in the keratin aggregates of clone 9 hepatocytes. In addition, histone deacetylase 6, a microtubule-associated deacetylase, was identified as a novel component of the keratin aggregates. Thus, together with their ultrastructural appearance as randomly oriented, organelle-free aggregates of keratin filaments, the keratin aggregates in clone 9 hepatocytes correspond to MBs. An imbalance in keratin 8 to18 with very low levels of keratin 18 appears to be the underlying cause for their formation. The formation of MBs was microtubule-dependent although not depending on the activity of histone deacetylase 6. Forskolin-induced MBs in clone 9 hepatocytes were reversible structures which disappeared upon drug withdrawal. The MBs were not related to aggresomes since overexpressed misfolded transgenic proteins were undetectable in the keratin aggregates and no vimentin fiber cage was detectable, both of which represent hallmarks of aggresomes. Thus, cultured clone 9 hepatocytes are a useful system to study further aspects of the pathobiology of MB

The ommatidia of Arca noae: a three-tier structure with a central light-guiding element for the receptor cell

The compound eyes of ark clams appear to function as an optical system to trigger shell closure against predators. We have analyzed the structure of the ommatidia of Arca noae by thin section electron microscopy and serial sectioning, Concanavalin A-gold labeling and acid phosphatase cytochemistry. Our results demonstrate that the ommatidia are a three-tier structure composed of a central single receptor cell, surrounded and covered by proximal pigment cells followed by rows of distal pigment cells. The receptor cells of Arca noae have no lens and the disks of their receptive segment are derived from sensory cilia. The distal mitochondrial segment in the cytoplasm between the nucleus and the receptive segment is surrounded by a mass of Concanavalin A-reactive glycogen particles. Although both, proximal and distal pigment cells have numerous microvilli, only those of the proximal pigment cells form a well-aligned brush border. The microvilli of the latter are ≈9-11μm long and have a diameter of ≈70-80nm. Numerous microlamellar bodies cover them. The microlamellar bodies are stored in acid phosphatase-negative secretory granules of the pigment granule-free apical cytoplasm of proximal pigment cells before their secretion. Observation of living compound eyes indicated that the apex of proximal pigment cells transmitted significantly more light than the surrounding distal pigment cells. Hence, the regular geometry of the brush border seems to be a light-guiding structure for receptor cells similar to an optical fibe

On the Growth of Al_2 O_3 Scales

Understanding the growth of Al2O3 scales requires knowledge of the details of the chemical reactions at the scale–gas and scale–metal interfaces, which in turn requires specifying how the creation/annihilation of O and Al vacancies occurs at these interfaces. The availability of the necessary electrons and holes to allow for such creation/annihilation is a crucial aspect of the scaling reaction. The electronic band structure of polycrystalline Al2O3 thus plays a decisive role in scale formation and is considered in detail, including the implications of a density functional theory (DFT) calculation of the band structure of a Σ7 View the MathML source bicrystal boundary, for which the atomic structure of the boundary was known from an independent DFT energy-minimization calculation and comparisons with an atomic-resolution transmission electron micrograph of the same boundary. DFT calculations of the formation energy of O and Al vacancies in bulk Al2O3 in various charge states as a function of the Fermi energy suggested that electronic conduction in Al2O3 scales most likely involves excitation of both electrons and holes, which are localized on singly charged O vacancies, View the MathML source and doubly charged Al vacancies, View the MathML source, respectively. We also consider the variation of the Fermi level across the scale and bending (“tilting”) of the conduction band minimum and valence band maximum due to the electric field developed during the scaling reaction. The band structure calculations suggest a new mechanism for the “reactive element” effect—a consequence of segregation of Y, Hf, etc., to grain boundaries in Al2O3 scales, which results in improved oxidation resistance—namely, that the effect is due to the modification of the near-band edge grain-boundary defect states rather than any blocking of diffusion pathways, as previously postulated. Secondly, Al2O3 scale formation is dominated by grain boundary as opposed to lattice diffusion, and there is unambiguous evidence for both O and Al countercurrent transport in Al2O3 scale-forming alloys. We postulate that such transport is mediated by migration of grain boundary disconnections containing charged jogs, rather than by jumping of isolated point defects in random high-angle grain boundaries

Importation of Hybrid Human-Associated Trypanosoma cruzi Strains of Southern South American Origin, Colombia.

We report the characterization of Trypanosoma cruzi of southern South American origin among humans, domestic vectors, and peridomestic hosts in Colombia using high-resolution nuclear and mitochondrial genotyping. Expanding our understanding of the geographic range of lineage TcVI, which is associated with severe Chagas disease, will help clarify risk of human infection for improved disease control