Showing papers by "University of Vienna published in 1975"

The acceptor number — A quantitative empirical parameter for the electrophilic properties of solvents

Abstract: The electrophilic properties of 34 solvents have been characterized by the Acceptor Number (AN) which has been derived from31P-n.m.r. measurements of triethylphosphine oxide dissolved in the respective solvents. Relationships are found between the acceptor numbers and theZ-values,E T-values andY-values, as well as the free energies of solvation of anions and the redox potentials of the hexacyanoferrate(III)—hexacyanoferrrate(II) system in different solvents. The new parameter provides—together with the donor number—a useful guide in choosing the most appropriate solvent for a given reaction.

Bound for the Kinetic Energy of Fermions Which Proves the Stability of Matter

Abstract: We first prove that Σ |e (V)|, the sum of the negative energies of a single particle in a potential V, is bounded above by (4/15 π )∫|V|5/2. This in turn, implies a lower bound for the kinetic energy of N fermions of the form 3/5 (3π/4)2/3 ∫ρ 5/3, where ρ (x) is the one-particle density. From this, using the no-binding theorem of Thomas-Fermi theory, we present a short proof of the stability of matter with a reasonable constant for the bound.

Histological subtypes and prognostic problems in meningiomas.

Abstract: The incidence of the various histological subtypes of meningiomas was examined in 1238 patients with surgically treated meningiomas, about 80% arising within the cranial cavity. The histological classification used was that of Courville (1950) and Rubinstein (1972), but “angioblastic” meningiomas were segregated into 3 groups: highly vascularized meningiomas, hemangioblastomas, and hemangiopericytomas. Endotheliomatous and transitional forms constituted 85% of the total (71.5% of intracranial tumors), fibroblastic forms 6.6 and 7.5%, respectively, and highly vascularized (endotheliomatous or transitional) meningiomas 5.2% of the intracranial tumors, while true “angioblastic” meningiomas (hemangioblastomas and hemangiopericytomas) amounted to 2.8% of the total (3.1% of the intracranial tumors). 1.2% were “atypical” (so-called malignant) meningiomas; true meningeal sarcomas were excluded.

Primary malignant lymphomas of the central nervous system in man.

Abstract: Sixty-eight primary malignant lymphomas of the CNS exclusively confined to the brain and its leptomeninges from a series of about 8000 intracranial neoplasms (incidence 0.85%) were examined and classified according to current histopathologic criteria. Average age at onset of symptoms was 55 years, mean duration of illness to time of diagnosis was 3 months. Survival averaged 1,8 months with supportive care, but 17,2 months with surgery, radiation and/or chemotherapy. CSF cytology was a useful and reliable tool for clinical diagnosis. The cerebral hemispheres were affected in about 50%, the basal ganglia in 18%, posterior fossa in 10%, while multifocal lesions amounted to 22%. All CNS tumors were of the diffuse type of non-Hodgkin’s lymphomas; no follicular (germinal center) lymphomas were observ. d. Three histological patterns comparable to extraneural lymphomas were distinguished: Immunoblastoma (reticulosarcoma) occurred most frequently (58.8%), lympho-plasmacytoid immunocytoma constituted 28 percent, while lymphoblastic lymphoma occurred least frequently (13.2%). There were no significant differences with regard to onset, location, growth pattern or clinical course except for a much poorer prognosis of lymphoblastic lymphoma. Although there are no definite cytological differences between malignant lymphomas arising in extraneural sites or as primary lesions in the CNS, the latter showed a much greater proportion of phagocyting histiocytes (and microglia) and a frequent occurrence of plasmacytes and their precursors which apparently exceeded pure host reaction. The prognostic value of modern classification schemes for CNS lymphomas needs further critical evaluation.

Topological dynamics of transformations induced on the space of probability measures

Abstract: LetT be a continuous transformation of a compact metric spaceX. T induces in a natural way a transformationTM on the spaceM (X) of probability measures onX, and a transformationTK on the spaceK (X) of closed subsets ofX. This note investigates which of the topological properties ofT∶X→X (like distality, transitivity, mixing property etc. ...) are “inherited” byTM∶M (X)→M (X) andTK∶K (X)→K (X).

Non-parallel dissociation of dislocations in thin foils

Abstract: The equilibrium shape of dissociated dislocations in thin foils of Cu-10 at.% Al is investigated by weak-beam electron microscopy. It is found that dislocations assume a truncated triangular shape caused principally by the reduction in line energy when Shockley partials rotate towards screw character. The effects of interaction image stresses and surface slip steps are generally small, but the former may be important in the case of spontaneous cross-slip of a dislocation at a surface.

Horizontal cells in cat retina with independent dendritic systems

Abstract: Cat horizontal cells are retinal neurons with two functionally distinct parts: the cell body receives signals predominantly from cones, while the terminal arborization receives predominantly from rods. The long thin process connecting these parts neither generates impulses nor allows significant passive electrotonic conduction between them.

Coexistence of lichen planus and bullous pemphigoid. A immunopathological study.

Abstract: A 43-year-old white man presented with a generalized eruption of lichen planus and tense blisters within the lichenoid lesions and also on clinically normal skin. Direct immunofluorescence (IF) studies revealed immunological and histopathological characteristics of lichen planus in the lichenoid lesions and of bullous pemphigoid in the bullous lesions, and indirect IF studies showed that the patient had circulating antibasement membrane antibodies. The coexistence of both disorders may indicate a possible link between the pathology in the junctional zone in lichen planus and the appearance of antibasement membrane zone antibodies and bullous lesions, respectively.

Salt regulation in halophytes

Abstract: Ion concentration and saturation water content were measured in various aged leaves of halophytes growing in saline soils east of lake Neusiedlersee (Austria).All species investigated showed a substantial sodium accumulation within the maturing organs accompanied by a considerable potassium decline. In most species chloride concentration rises distinctly with increasing leaf age, too, whereas concentration shifts of alkaline earth ions and of sulfate (except in Plantago maritima, Lepidium crassifolium and Crypsis aculeata) are of comparably less importance.Saturation water increases markedly in succulent species (Suaeda maritima, Chenopodium glaucum, Spergularia media, Lepidium crassifolium) and to a less degree in xerophytic monocotyledons (Puccinellia distans, Crypsis aculeata, Bolboschoenus maritimus). However, this surplus of water in older leaves is not sufficient to dilute the salt to such an extent that a rise in concentration can be prevented (except chloride in Suaeda maritima and Chenopodium glaucum).Rosette plants (Triglochin maritimum, Plantago maritima, Scorzonera parviflora, Aster tripolium) with the ability to renew their leaves continuously throughout the growth period are characterized by only insignificant changes of saturation water content with increasing leaf age. In these plants, shedding of old salt-saturated leaves is thought to be the main strategy for salt regulation.A modification of Steiner's classical concept of different "salt regulation types" is proposed, based on original findings about salt regulation in Austrian halophytes and on new bibliographical data upon additionally revealed regulatory principles in halophytes and saltaffected nonhalophytes.

The significance of perivascular infiltrations in multiple sclerosis

Abstract: 143 autopsy cases of multiple sclerosis (19 acute and 124 chronic cases) were analysed histologically for the extent of active demyelination and the degree of infiltration within and outside the demyelinating lesions and in the leptomeninges. The results were compared with the duration of the illness. Infiltrations were found in 60% of all cases but more often (74%) in those with active demyelination. Inflammatory lesions outside demyelinating foci were observed in 27% of the total, and in 80% of them active demyelination was present. Inflammatory lesions in the meninges were present in 41% of the total and in 80% of these were accompanied by active demyelination. The duration of illness correlated with decreasing severity of active demyelination and of perivascular infiltration. Patients treated with cortico-steroids and/or immunosuppressive substances showed no or only moderate inflammatory lesions. The duration of illness in both these groups was significantly longer than the average of untreated patients. The significance of these pathological findings for the CSF cytology in multiple sclerosis is discussed.

The Thermodynamic Limit for Jellium

Abstract: The thermodynamic limit of the free energy, energy, pressure, and entropy is established for a neutral system of charged particles interacting with a fixed, uniformly charged background (jellium)

Internal structure of cat extraocular muscle.

Abstract: Teasing preparations of cat extraocular muscles (EOM) were used to study the arrangement of muscle fibers and the distribution of the different cholinesterase-positive sites, i.e. (1) large motor endplates, (2) small motor endings of the “en grappe” type, (3) myotendinous junctions and (4) myomyous junctions. The distribution of these cholinesterase-positive structures gives clear evidence of a complex muscle architecture of cat EOM. In the global layer of cat EOM, only multiply innervated muscle fibers run the whole length of the muscle. The focally innervated muscle fibers are generally shorter; they are usually arranged in series of two to three fibers being interconnected by myomyous junctions. Moreover, muscle fiber splitting is frequently present resulting in a netlike arrangement of muscle fibers. Most of the myomyous junctions occur between focally innervated muscle fibers, but also end-to-side connections of focally to multiply innervated muscle fibers are observed; multiply innervated muscle fibers have not been found connected to each other. In this layer, large motor endplates are distributed in several bands between origin and insertion. In the orbital layer all muscle fibers run from tendon to tendon, focally as well as multiply innervated ones. Here, large motor endplates are confined to a band in the middle of the muscle, and myomyous junctions are generally absent.

Taurine uptake in synaptosomal fractions of rat cerebral cortex.

Abstract: — [35S]Taurine was found to be accumulated in synaptosomal fractions of rat cerebral cortex. Kinetic analysis in the range of 1–800 μm-[35S]taurine revealed at least two different uptake processes. A high affinity uptake with a Km of 20 μM and a low affinity uptake with a Km of about 450 μM. The high affinity component was dependent on temperature and energy, and virtually abolished in the absence of sodium. Examination of the influence of structural analogues and putative transmitter substances indicates that the high affinity uptake of taurine into synaptosomal fractions of rat cerebral cortex is unique and highly specific. No specific actions of several centrally acting drugs on taurine uptake could be observed.

Exact quantum transition probabilities by the state path sum method: Collinear F + H2 reaction

Abstract: Exact quantum mechanical transition probabilities have been calculated for the collinear F + H2 →H + HF reaction by the State Path Sum method. The potential energy surface used is based on the ab initio SCF CI surface of Bender et al. For the energy range considered, four product channels are open. Pronounced level inversion is found. The dominant transition is the 3 ←0 one. It has a resonance-like energy dependence which is similar to that for the 2 ←0 transition. The 1 ←0 and 0 ←0 transition probabilities are negligible. These results are compared with those of Wu et al. and Schatz et al. who use semi-empirical LEPS surfaces.

Metabolic changes in the course of severe acute Brain Damage

Abstract: 27 Patients following severe brain injury were studied with regard to metabolic alterations. Metabolic rate was calculated from measured RQ, respiratory minute volume and oxygen consumption, as soon as the patient was able to breathe spontaneously. Catabolism was defined by determination of N-balance. It was concluded that metabolism following cerebral injury is particularly enhanced compared to common trauma. The neurological course of patients, who after midbrain syndrome recovered in contrast to those who developed apallic syndrome had little influence on metabolic rates, however, it distinctly seemed to modify catabolism. Thus catabolism throughout the apallic phase was found to be higher. The requirements for a favourable recovery from severe brain injury were defined as a well balanced nitrogen regime apart from a high amount of carbohydrate and fat calories.

Regeneration of a transected peripheral nerve. An autoradiographic and electron microscopic study.

Abstract: The regeneration of transected peripheral nerves of mice was studied using autoradiographical and electron microscopical techniques. In general, maximal proliferation occurred between the 5th and 7th day after dissection and stopped when the cells emigrating from the proximal and distal stumps of the nerve started to contact one another. Special attention was paid to the reaction of the connective tissue cells of the endo-, epi- and perineurium. The perineurial cells seemed to dedifferentiate between the 3rd and 5th day after the transection and then started to proliferate into the defect. Labelled perineurial cells were completely absent, when the minifascicles were fully developed in the neuroma. The epineurial fibroblasts started to proliferate during the 1st day. Even 6 weeks after transection the multiplication rate was about ten fold that of the controls. The results are discussed with special reference to clinical nerve repair.

Partially resected and irradiated cerebellar astrocytoma of childhood: malignant evolution after 28 years.

Abstract: Partial resection of a cystic cerebellar astrocytoma with well-differentiated histomorphology in a 13 year old girl was followed by a course of X-ray therapy. After a period of 27 years symptoms recurred. The patient died 2 days after a second operation, and autopsy showed a large partly cystic cerebellar astrocytoma with distinct morphological evidence of malignancy in some areas. The role of the X-ray therapy in the formation of peculiar bizarre giant cells in our case is discussed. Radio-induction of malignant tumour evolution after long latency has to be considered, but the possibility seems remote. However, the value of radiotherapy for cystic cerebellar astrocytomas needs some reconsideration. More caution in the long term prognosis of cystic cerebellar astrocytomas of childhood might be appropriate.

Über Aminosäuren und Peptide, XIV. Über Dehydroaminosäuren, II. Dehydroaminosäuren aus Aminosäuren

Abstract: α-Iminocarbonsaurederivate, wie Ester (6) und Amide (7), wurden durch N-Chlorierung und Dehydrochlorierung aus ihren Aminosaureverbindungen gewonnen. – α-Acylaminosaureverbindungen liesen sich unter Alkoholatkatalyse N-chlorieren. Alkoholat in Alkohol fuhrte uber Dehydrochlorierung und Alkoholaddition zu α-N-Acyl-α-alkoxy-aminosaureverbindungen (z. B. 16). Ohne protonenhaltiges Losungsmittel mit Diazabicycloundecen entstand die N-Acyl-α,β-dehydroverbindung 17, die sich auch aus der α-Alkoxy-α-acylaminoverbindung 16 mit Saure bildete. – Die Reaktionsreihe 13 17 bietet einen einfachen Weg von der Aminosaure zur Dehydroaminosaure, z. B. N-Acetyldehydrovalinester (17), N-Acetyldehydroleucinester (18) und α-Acetylaminocrotonsaureester (19). Weder neben den α-Iminoverbindungen noch neben den N-Acyl-enaminen haben wir die Tautomeren registriert. On Amino Acids and Peptides XIV. On Dehydro Amino Acids, II Dehydro Amino Acids from Amino Acids Derivatives of α-imino carboxylic acids like esters (6) and amides (7) can be obtained by N-chlorination and dehydrochlorination of their amino acid compounds. – α-Acylamino acid compounds were N-chlorinated by alcoholate catalysis. Alcoholate in alcohol leads to N-acyl-α-alkoxyamino acid compounds (e.g.16) via dehydrochlorination and addition of alcohol. Using diazabicycloundecene without proton containing solvents we obtained the N-acyl-α,β-dehydro compound 17. This is also formed by the reaction between α-alkoxy-α-acylamino compounds (e.g. 16) with acids. – The reaction sequence 13 17 represents a simple way to prepare the dehydroamino acid from the amino acid, e. g. N-acetyldehydrovaline ester (17), N-acetyldehydroleucine ester (18), and α-acetylamino crotonic acid ester (19). We found no tautomers, neither with the α-imino compounds, nor with the N-acylenamines.

Bandstruktur des Festkörpers – Interpretation der chemischen Bindung in einigen Übergangsmetallverbindungen aufgrund von Bandstrukturrechnungen

Abstract: Die chemischen Bindungsverhaltnisse einiger in der NaCl-Struktur kristallisierenden Ubergangsmetallverbindungen (ScN. ScO, TiC, TiN, TiO, VC, VN, VO) werden auf Grund von Bandstrukturrechnungen diskutiert. Grundlage der Betrachtungen bilden die nach der quasi-selbstkonsistenten APW-Methode berechneten Wellenfunktionen und Energieeigenwerte sowie die nach dem LCAO-TB-Inter-polationsverfahren von Slater und Koster ermittelten Energieeigenwerte und Eigenvektoren. Die partiellen LCAO-TB l-Zustandsdichten erlauben eine Analyse der Valenzbander, aus der hervorgeht, das das energetisch tiefstliegende Valenzband nahezu ausschlieslich s-Charakter besitzt. In den folgenden Bandern, die sich im wesentlichen von den Nichtmetall 2p-Atomzustanden herleiten, besitzt die LCAO-TB-Zustandsdichte neben einem hohen Anteil an partieller p-Zustandsdichte auch einen deutlichen Beitrag an partieller d-Zustandsdichte, der sich vom Karbid zum Oxid verringert. In der LCAO-TB-Zustandsdichte der funf Bander, die sich von den Metall-3d-Atomzustanden herleiten, findet man neben einem uberwiegenden Anteil an partieller d-Zustandsdichte auch einen kleineren Beitrag an partieller p-Zustandsdichte. Die partielle d-Zustandsdichte wird in den eg- und t2g-Anteil zerlegt und deren Verhalten diskutiert. Eine Analyse der APW-Kristallwellenfunktionen gibt Aufschlus uber die l-artigen Ladungen in den Atomspharen. Auf Grund eines Vergleichs der APW-Gesamtladungen in den Atmospharen mit den Ladungen, die sich durch die Uberlagerung der Ladungsdichten eines hypothetischen Kristalls neutraler Atome ergeben, wird auf eine Uberfuhrung von Elektronen geschlossen, die in allen Verbindungen aus der Metallatomsphare in die Nichtmetallatomsphare erfolgt. The nature of chemical binding for some transition metal compounds (ScN, ScO, TiC, TiN, TiO, VC, VN, VO) with NaCl structure is discussed in terms of energy band structure calculations. The discussion is based on the wave functions and energy eigenvalues, as calculated by the “Quasi self consistent APW method” as well as on the energy eigen values and eigen vectors resulting from the Slater-Koster LCAO-Tight binding interpolation scheme. The LCAO-TB l-like partial density of states can be used to analyse the valence bands. This analysis shows, that the deepest valence band has predominantly s-character. The following bands, which can be derived in essence from the atomic 2p states of the non metal are characterized not only by the partial p-like density of states but also by a substantial contribution from the d-like partial density of states, which is decreasing going from a particular Carbide to the corresponding Oxide. For the valence bands, which can be associated with the atomic 3d states of the metal, the density of states exhibits besides the partial d-density of states small contributions from the partial p-like density of states. The decomposition of the d-like partial density of states into an eg-like and a t2g-like contribution is discussed. By analyzing the APW crystal wave functions the partial l-like charges inside each atomic sphere can be obtained. If the APW total charges within the atomic spheres are compared with the charges of a hypothetical crystal, which correspond to a superposition of the charge densities of the neutral atoms, a transfer of electrons from the metal to the non-metal sphere is found for all compounds under investigation.

Heterogeneity of heterochromatin in plants: Comparison of Hy- and C-bands inVicia faba

Abstract: The comparison of Hy- and C-bands reveals three types of heterochromatin (Hy+, Hy−, and Hy 0) inVicia faba. By C-banding, the total of constitutive heterochromatin is identified. The Hy-banded heterochromatin is restricted to the M-chromosome: The nucleolus-associated heterochromatin appears as two darkly stained (Hy+)-bands bordering the secondary constriction, while reduced staining (Hy−)-bands are located near the centromere. The heterochromatin of the S-chromosomes is of the (Hy 0)-type, i.e., it does not respond to the Hy-banding procedure. A complete karyogram of the C-banded chromosome complement is presented and discussed. A comparison of C-bands and cold-sensitive segments clearly shows that negatively as well as positively reacting cold-induced segments are partly heterochromatic, partly euchromatic.