Showing papers by "University of Erlangen-Nuremberg published in 1983"

Efficient diffuse function‐augmented basis sets for anion calculations. III. The 3‐21+G basis set for first‐row elements, Li–F

Abstract: The relatively small diffuse function-augmented basis set, 3-21+G, is shown to describe anion geometries and proton affinities adequately. The diffuse sp orbital exponents are recommended for general use to augment larger basis sets.

Speckle masking in astronomy: triple correlation theory and applications

Abstract: Due to the turbulent atmosphere the resolution of conventional astrophotography is limited to ∼1 sec of arc. However, the speckle-masking method can yield diffraction-limited resolution, i.e., 0.03 sec of arc with a 3.6-m telescope. Speckle masking yields true images of general astronomical objects. No point source is required in the isoplanatic field of the object. We present the theory of speckle masking; it makes use of triple correlations and their Fourier counterparts, the bispectra. We show algorithms for the recovery of the object from genuine astronomical bispectra data.

Quasiparticle energy-band structures in semiconducting polymers: Correlation effects on the band gap in polyacetylene

Abstract: Single- and many-particle effects contributing to the formation of energy-band gaps in semiconducting polymers are investigated using exact-exchange Hartree-Fock (HF) theory and Toyozawa's electronic-polaron model. The electron correlation is calculated by M\o{}ller-Plesset perturbation theory including explicitly all significant matrix elements in second order. Their efficient calculation is facilitated by the use of optimally localized Wannier functions. The importance of both short- and long-range contributions, of extended atomic basis sets, and of the use of the full virtual space is exhibited in the case of trans-polyacetylene (PA) as a model system. Correlation effects are shown to reduce the single-particle energy-band gap first by diminishing the bond alternation in PA. On the other hand, due to the self-energy corrections, the HF energy-band states are transformed to quasiparticle (electronic-polaron) states, the valence band is shifted upward, and the conduction band is shifted downward. The original HF energy-band gap of 5 eV is reduced to 3 eV at an estimated level of 70-75% of valence-shell correlation. Its extrapolated value for full correlation is found to be 2.5 eV. The remaining 0.5-eV difference between theory and experiment is assigned to phonon-polaron and relaxation effects.

Characterization of human papillomavirus type 13 from focal epithelial hyperplasia Heck lesions.

Abstract: Focal epithelial hyperplasia Heck lesions of a Turkish patient were shown to contain papillomavirus-specific DNA, which was molecularly cloned into bacteriophage lambda. It proved to be related to human papillomavirus (HPV) type 6 DNA and HPV type 11 DNA. Reassociation kinetics revealed a cross-hybridization of 4 and 3%, respectively. There was no cross-reactivity with HPV type 1, 2, 3, 4, 5, 8, or 10. This papillomavirus type will be referred to as HPV type 13. The DNA was characterized by cleavage with several restriction enzymes, and the cleavage sites were physically mapped. Papules from two additional cases of Morbus Heck contained HPV type 13 DNA as shown by Southern blot hybridization and by the characteristic cleavage patterns. This may indicate that HPV type 13 is more frequently associated with focal epithelial hyperplasia Heck than are other HPV types.

Image reconstruction by the speckle-masking method

Abstract: Speckle masking is a method for reconstructing high-resolution images of general astronomical objects from stellar speckle interferograms In speckle masking no unresolvable star is required within the isoplanatic patch of the object We present digital applications of speckle masking to close spectroscopic double stars The speckle interferograms were recorded with the European Southern Observatory's 36-m telescope Diffraction-limited resolution (003 arc see) was achieved, which is about 30 times higher than the resolution of conventional astrophotography

Automorphisms of Enriques Surfaces

Abstract: O. Introduction The aim of this note is to compute the group Aut(Y) of (biholomorphic) auto- morphisms for the general Enriques surface Y. The basic tool is the global To- relli theorem for projective K3-surfaces as it was given by Piatetski-Shapiro and Shafarevich [11] and refined by Burns and Rapaport [2]. The essential result is that - in contrast to the case of curves - Aut (Y) is big for general Y and small for special Y. In this paper we consider the complex case only. Recall that an Enriques surface Y is a (projective) complex surface with universal double cover a K3- surface. One knows that H2(Y, Z)= 7Z, ~ ~ 2~ 2 and that the cup-product provides

Theoretical studies of possible excitonic superconducting state in CuCl and CdS

Abstract: To explain the observed diamagnetic anomalies which are coupled with high conductivity in CuCl and CdS samples, an excitonic mechanism of superconductivity based on the presence of impurities is outlined. To formulate the theoretical model on a more fundamental level, four-component field operators have been introduced in analogy to the Nambu formalism. Generalized Eliashberg equations for the self-energy are derived for both singlet and triplet pairs. Numerical model calculations for the effective interaction are presented for different impurity concentrations and different gaps (exciton frequencies). Conjectures for the further development of the theory, together with proposed experiments, conclude this study.

Carbonic anhydrase distribution in the human and monkey eye by light and electron microscopy.

Abstract: The distribution of carbonic anhydrase (CA) in the eye of man and three species of monkeys was studied by light and electron microscopy using the histochemical method of Hansson. Carbonic anhydrase staining was found in the corneal endothelium. In monkeys the endothelial cells covering the inner surface of the operculum were also stained, whereas in the human the staining stopped at Schwalbe's line. In the trabecular meshwork no cells exhibited CA staining. The iris dilator muscle showed some staining, while no clear staining was found in the pigment epithelium (PE). In the ciliary body both the PE and the non-pigmented epithelium (NPE) displayed CA staining, most prominently in the basal and lateral membranes but also discernible in the cytoplasm. The staining of the NPE (but not the PE) showed clear-cut regional differences, and the presence of CA coincided with morphological indicators of secretory activity. Heavy staining was found in the capillaries under the ciliary epithelium. In the pars plana many capillaries showed staining of only that part of the circumference of the vessel wall which faced the epithelium. Unstained segments were also found in many choroidal capillaries under the pigmented epithelium of the retina. In the retina itself CA stain was found in the pigmented epithelium, in the Muller cells and in capillaries supplying the inner retina (only monkey retina was studied).(ABSTRACT TRUNCATED AT 250 WORDS)

Progressive pseudorheumatoid arthritis of childhood (PPAC). A hereditary disorder simulating rheumatoid arthritis.

Abstract: Five patients are described with a hereditary arthropathy affecting major and minor joints. The main features of this progressive connective tissue disorder are restricted joint mobility, osseous swelling of the interphalangeal and other joints, and platyspondyly. The condition is commonly misdiagnosed as “chronic juvenile polyrthritis with Scheuermann disease”. It differs from the rheumatoid-factor-negative polyarticular form of rheumatoid arthritis and other rheumatoic spondylarthropathies by the absence of arthritic and other inflammatory changes, radiographically by the absence of destructive and the presence of dysplastic bone changes. The disorder does not seem to respond to the usual forms of antirheumatoid treatment. Histological studies showed a peculiar, nest-like clustering of chondrocytes in the resting and growth cartilage suggesting that pathogenetically this is a primary disorder of the articular cartilage.

Non-acidic pyrazoles: inhibition of prostaglandin production, carrageenan oedema and yeast fever.

Abstract: Prostaglandin production from mouse peritoneal macrophages was elicited by the tumour promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The inhibitory potency (IC50) of metamizole and its major metabolites as well as other non-acidic pyrazoles was defined in this system. A reliable IC50-value could not be assigned to metamizole. Isopropylaminophenazone was as active as acetylsalicylic acid while aminophenazone and methylaminophenazone, the major metabolites of metamizole, were about 10 times and phenazone 100 times less potent than acetylsalicylic acid. The major excretion products of metamizole, 4-formyl- and 4-acetyl-aminophenazone were inactive. The IC50-values obtained agree with those necessary for manifestation of anti-inflammatory effects in rats but are up to 10 times higher than those measurable in human plasma after administration of analgesic-antipyretic doses.

Fossildiagenese im miozänen Leitha-Kalk der Paratethys von österreich: Ein Beispiel für Faunenverschiebungen durch Diageneseunterschiede

Abstract: Der miozane Leithakalk (Badenien) im Wiener Becken und in der S-Steiermark ist durch eine reichhaltige Fauna und Flora gekennzeichnet. Im Schliffbild dominieren Corallinaceen (Lithothamnium, Mesophyllum, Lithophyllum, Archaeolithothamnium, Palaeothamnium). Die ebenfalls sehr reiche Foraminiferenfauna kann in einzelnen Faziestypen die Corallinaceen an Haufigkeit ubertreffen. Faziell sind im Leithakalk zwei Hauptfaziestypen entwickelt: eine bioklastische Schutt-Fazies mit nur schwacher Zementation (mit Ausnahme eines Profils, in dem eine grobsparitische Zementation vorliegt). Die bioklastischen Schutt-Faziestypen konnen ebenso wie die Foraminiferen-Schutt-Faziestypen durch die Haufigkeit und Korngrose der Rhodolithen und deren Fragmente untergliedert werden: So weist die bioklastische Algen-Schutt-Fazies nur eckigen bis masig gerundeten Corallinaceen-Schutt auf, wahrend die bioklastische Rhodolithen-Schutt-Fazies auch einzelne ganze Rhodolithen enthaalt. Einen Sondertyp stellt die bioklastische Algen-Mollusken-Fazies dar, in der zahlreiche Mollusken den Kern der sie laminar umwachsenden Rhodolithen bilden. Die Bioklasten-Fazies besteht uberwiegend aus feinen, ursprunglich aragonitischen Bioklasten, die systematisch nicht mehr zugeordnet werden konnen. Kleine Riffkorper sind durch die Bafflestone-Fazies charakterisiert, in der verzweigte Korallen, massive Korallen und Bryozoen als Sedimentfanger auftreten. Die Pflaster-Fazies zeichnet sich durch lagenweise auftretende Rhodolithen aus; diese lateral nicht weit zu verfolgenden Rotalgenonkoide werden als Rinnenfullung interpretiert. Die Foraminiferen-Rhodolithen-Schutt-Fazies und die Foraminiferen-Algen-Schutt-Fazies gleichen den bioklastischen Typen, es fehlen jedoch die ursprunglich aragonitischen Bioklasten, und die Foraminiferen treten deutlich in den Vordergrund. Die Foraminferen-Fazies entspricht einem Foraminiferensand (bis zu 1200 Individuen auf 12 cm2 Schliff-Flache). In den Profilen tritt ein lebhafter Fazieswechsel auf, der im Zusammenhang mit der palaogeographischen Entwicklung steht. Die bioklastischen Schutt-Faziestypen haben sich hinter kleinen Riffchen gebildet. Die Bioklasten-Fazies steht in engem Zusammenhang mit den Riffen; im “Vorriffbereich” Uberwieger. die Foraminiferen-Schutt-Fazies-typen, Hier konnen stellenweise auch mergelige Kalke entwickelt sein, die durch ihre Foraminiferenfauna mit Globigerinen und Uvigerinen auf die Nahe von tieferen Beckensedimenten hinweisen. Diese Entwicklung ist am Sudrand des Leithagebirges vorhanden. Im Unterschied dazu sind die Foraminiferen-Schut-Faziestypen von St. Margarethen in sehr kustennahen Bereichen abgelagert worden und zeigen keinerlei Anzeichen vorriffahnlicher Bildungen. In diesen Karbonatsanden treten immer wieder fossilarme, geringmachtige Tonlagen auf, die in lebensfeindlichen, abgeschnurten Becken entstanden sind. Diese lagunenahnlichen Wannen wurden durch wiederholtes Trockenfallen der Karbonatsande vom normal-marinen Milieu abgeschnurt. Diese besonders im stratigraphisch jungeren Abschnitt zu beobachtende Entwicklung findet ihren Abschlus in der endgultigen Heraushebung im Sarmat und der damit verbundenen Entstehung einer Steilkuste mit Brandungsgerollen. Die unterschiedliche palaogeographische Entwicklung ausert sich auch sehr deutlich in der Lithofazies der Leithakalke, die drei Haupttypen zeigt (Abschnitt 7): 1) Die festzementierten Kalke vom Typ Fenk sind als bioklastische Schutt-Faziestypen und als Bafflestone-Fazies entwickelt. Die sehr starke Zementation ist auf eine primare mikritische Zementation zuruckzufuhren, wobei ursprunglich Mg-Kalzit abgeschieden wurde. Die weitere Diagenese erfolgte vorwiegend im phreatischen Suswasserbereich. Vadose Bildungen von Kristallsilten sind in den festzementierten Kalken selten. 2) Auch der zweite Typ, die kreidigen Kalke von Mullendorf, unterlagen einer phreatischen Suswasserdiagenese, in der die hohe Durchflusgeschwindigkeit der eindringenden Wasser nur eine auserst schwache Zementation zuliese, 3) In den Karbonatsanden von St. Margarethen uberwiegen bedingt durch das wiederholte synsedimentare Trockenfallen der Karbonatsande vadose Erscheinungen. Die primare marine Zementation war gering und ausert sich nur in dunnen Mikritzementen. Die sparitischen Zementbander in diesen Karbonatsanden entstanden in einem Mischbereich von marinen und vadosen Wassern. Meniskus- und Dripstone-Zemente weisen auf ein vadoses Milieu hin. Die wechselnden Diagenesebedingungen werden auser durch die Zementgefuge auch durch die Verteilungsmuster von Mg und Sr angezeigt. Die verschiedenartigen Diagenesebereiche spiegeln sich auch sehr deutlich in der Erhaltung der Fossilien wider (Abschnit 8): In den Karbonatsanden sind alle aragonitischen Fossilien durch Losung verschwunden; gleichermasen die kleinen Bioklasten, ohne irgendwelche Reliktstrukturen zu hinterlassen. Auch Hohlformen fehlen. Aragonitische Fossilien sind nur dort erhalten, wo sie durch Corallinaceen umkrustet sind. Im Unterschied dazu sind in den festzementierten und kreidigen Kalken auf Grund der vorwiegend phreatischen Suswasserdiagenese Hohlformen und umkristallisierte aragonitische Fossilien uberliefert. Kalzitische Fossilien wie Austern und Pectiniden treten uberall auf und besitzen noch ihre ursprungliche Schale, wobei nur eine schwache Sammelkristallisation zu beobachten ist. Von Interesse ist die bei aragonitischen Mollusken aus den mergeligen Beckensedimenten feststellbare allmahliche Umwandlung der Schale, die zur volligen Struktur auflosung wie in den festzementierten und kreidigen Kalken fuhrt, Hierbei konnen aus in ihrer primaren Entstehung verschiedenen Strukturen durch sanfte Umwandlung optisch gleichartige Strukturen entstehen: Bei der Perlmuttstruktur der Archaeogastropodenschalen konnte eine Umwandlung in eine Kreuzlamelle durch kalzitische Neubildungen beobachtet werden. Das gemeinsame Auftreten der beiden Strukturtypen in eine und derselben Schale von fossilen Mollusken mus daher diskutiert werden (Abschnitt 8.2). Bei den aus Mg-Kalzit bestehenden Corallinaceen sind ebenfalls graduelle Strukturveranderungen festzustellen, wobei eine allmahliche Kristallvergroberung fur die Strukturumwandlung verantwortlich ist (Abschnitt 8.1). Die unterschiedliche Schalenmineralogie der biogenen karbonatischen Skelettelemente fuhrt wahrend der Diagenese zu einer Verschiebung der ursprunglichen Faunen- und Florenzusammensetzung. Besonders stark wirkt sich dies bei den Mollusken aus: Die Aragonitschaler werden dezimiert und die Kalzitschaler “reichern” sich durch Losung an und konnen, wie in den Karbonatsanden von St. Margarethen, die einzigen erhaltenen Mollusken sein. Vergleichbare diagenetische Veranderungen des Faunenspektrums werden auch durch den Vergleich von Faunen rezenter Karbonate im Golf von Agaba mit den Faunen in faziell entsprechenden, gehobenen Terassen bestatigt (Abschnitt 9).

Regioselektive Metallierung von Aromaten, II. Zweitmetallierung von 1-Lithionaphthalin und 9-Lithioanthracen

Abstract: Sowohl 1-Lithionaphthalin (2) als auch 9-Lithioanthracen (12) werden durch n-Butyllithium in Gegenwart von N,N,N′,N′-Tetramethylethylendiamin (TMEDA) spezifisch metalliert, wobei ein zweites Lithiumatom in der benachbarten peri-Position eingefuhrt wird (5, 18). MNDO-Berechnungen liefern eine Erklarung fur solche gerichteten Zweitmetallierungen, fur die andere Beispiele bekannt sind. Nicht nur sind die dilithiierten Produkte durch symmetrische doppelte Uberbruckung stabilisiert (thermodynamische Triebkraft), sondern es werden auch die aktivierten Wasserstoffatome in den monolithiierten Vorstufen richtig erkannt. Die LUMO-Koeffizienten und die CH-Bindungslangen sind hier am grosten. Realistischere Modelle fur die Verbindungen in Losung, namlich Dimere, zeigen die gleiche Charakteristik. Regioselective Metallation of Aromatic Compounds, II. Second Metallation of 1-Lithionaphthalene and 9-Lithioanthracene Both 1-lithionaphthalene (2) and 9-lithioanthracene (12) undergo specific metallations whereby a second lithium is introduced at the adjacent peri-positions (5, 18) (in the presence of n-butyllithium/N,N,N′,N′-tetramethylethylenediamine (TMEDA)). Explanations for such directed second metallations, for which other examples are known, are provided by MNDO calculations. Not only are the dilithiated products stabilized by symmetrically double bridging (implying a thermodynamic driving force) but also the activated hydrogens in the monolithio precursors are indicated clearly. The LUMO-coefficients on these hydrogens are largest and the CH bond lengths longest. Dimers, more realistic models for the solution species, show these characteristics as well.

Perturbation theoretical investigation of electron correlation effects in infinite metallic and semiconducting polymers

Abstract: Moller–Plesset-type perturbation theory is applied to calculate electron correlation effects in infinite, periodic, metallic, and semiconducting polymers. Different possible choices of the zeroth-order Hamiltonian (symmetry adapted Hartree–Fock, spin-, and charge-density waves), the influence of the size of the atomic basis sets, lattice and conduction band sums are investigated. In the case of semiconducting systems a very efficient version of the method using optimally localized Wannier functions has been worked out. Applications include model calculations for infinite atomic hydrogen chains, the investigation of the role of correlation effects in the bond alternation and metal-insulator phase transition in polyene, different one-and many-particle effects contributing to the single-particle gap in polyene, and the calculation of correlated quasiparticle band structures using the electronic polaron model.

The pathogenesis of trypanosomiasis of the CNS. Studies on parasitological and neurohistological findings in trypanosoma rhodesiense infected vervet monkeys.

Abstract: Parasitological examinations of the cerebrospinal fluid of 20 vervet monkeys (Cercopithecus aethiops), that had been infected with Trypanosoma rhodesiense, revealed that the CSF was regularly infested with trypanosomes in the early phase of the disease, at the earliest on the 13th day, in most of the animals in the 3rd or 4th week, after infection. Follow-up examinations of the CSF during the further course of the disease also regularly proved positive for trypanosomes. Histological studies in the animals that died at a mean of 65 days after infection (range 35 to 107 days) revealed encephalitis in the animal with the longest course of the disease. In all the other animals, meningitis alone was found. This was accompanied by a modified early encephalitic reaction, characterized by lympho-plasma-cellular infiltrates exclusively in the adventitial sheaths of those blood vessels passing into the brain from the leptomeninges affected by inflammatory infiltration. The early encephalitic reaction is interpreted as the morphological manifestation of an infestation of the perivascular spaces (Virchow-Robin spaces) with parasites. It indicates that CSF parasitosis in the early phase represents the point of departure for the encephalitis that develops in the late phase of the disease, and that the encephalitis presumably develops as a result of the migration of the trypanosomes out of the subarachnoid space into the perivascular spaces, and from there into the brain.