Showing papers by "University of Bonn published in 1983"
TL;DR: In this article, the authors considered the special cases of an elliptic equation with time as parameter, that is, b(z)= 0, and the standard parabolic equation, that are, b (z)=z are included.
Abstract: The structure conditions are the ellipticity of a and the (weak) monotonicity of b, and b has to be a subgradient in case m > 1. First we treat the case that b is continuous, and later (Sect. 4) we include Stefan problems, that is, we allow b to have jumps. The special cases of an elliptic equation with time as parameter, that is, b(z)= 0, and the standard parabolic equation, that is, b(z)=z are included. Some special single equations of mixed elliptic and parabolic type are given in the following. The gas flow through a porous medium is described by the equation
1,012 citations
TL;DR: In this article, the Dirichlet problem for Quasilinear Equations is studied in the context of Communications in Partial Differential Equations (CIPE), and the authors propose a method to solve it.
Abstract: (1983). On The Dirichletproblem for Quasilinear Equations. Communications in Partial Differential Equations: Vol. 8, No. 7, pp. 773-817.
384 citations
TL;DR: In this paper, the authors give a general construction for supersymmetric Hamiltonians in quantum mechanics and show that N-extended supersymmetry imposes very strong constraints, and for N > 4 the Hamiltonian is integrable.
316 citations
254 citations
TL;DR: A nomenclature is proposed designating not only the migration pattern of the C4 variants in agarose gels but also the heterogeneity of theC4 chains observed in SDS-PAGE, which resulted in a total of 11 variants in the population studied.
216 citations
TL;DR: In this article, decomposition properties of graphs not contractible to K"5 were used to describe the polyhedron of cuts and to give a polynomial algorithm for the max-cut problem.
159 citations
TL;DR: During environmental anaerobiosis, when the whole organism is exposed to anoxic conditions caused by external, physical factors in the microhabitat, arginine phosphate, glycogen, and aspartate (only mollusks) are the substrates for the metabolism.
Abstract: During environmental anaerobiosis, when the whole organism is exposed to anoxic conditions caused by external, physical factors in the microhabitat, arginine phosphate, glycogen, and aspartate (only mollusks) are the substrates for the metabolism. Main end products formed are lactate (Crustacea, Xiphosura, some Gastropoda and Bivalvia), alanine, succinate, and the volatile fatty acids, propionate and acetate (most Gastropoda and most Bivalvia). Because of reduction of the overall metabolism in bivalves, utilization and production rates of substrates and end products, respectively, are low. They are generally faster in Crustacea, which do not reduce their metabolism.
During functional anaerobiosis, when the muscle tissue becomes anoxic because of increased work done by the animal, energy is derived from arginine phosphate and glycogen. The main end products formed are lactate (Crustacea), octopine (active Gastropoda and Bivalvia), and strombine/alanopine (some gastropod species). Utilization rates of the phosphagen and production rate of lactate and opines are sometimes more than 500-fold higher than during environmental anaerobiosis. These strong variations in the glycolytic flux are probably regulated by the influence of the phosphagen and adenylates on regulatory enzymes and by the NADH/NAD ratio.
152 citations
TL;DR: In this article, a system of classification and naming of general application to host-guest-type compounds is proposed, which is based on several criteria, including the hostguest type and the host guest interaction, but also on topological and numerical considerations.
Abstract: We suggest a system of classification and naming of general application to host-guest-type compounds. The classification is based on several criteria, including the host-guest type and the host-guest interaction, but also on topological and numerical considerations. The application of this concept to the classification of any host-guest situation is illustrated by several examples.
132 citations
TL;DR: It is shown that for arbitrary real edge costs the travelling salesman problem can be polynomially solved for such a graph, and an explicit linear description of the travelled salesman polytope is given.
Abstract: A Halin graphH=T∪C is obtained by embedding a treeT having no nodes of degree 2 in the plane, and then adding a cycleC to join the leaves ofT in such a way that the resulting graph is planar. These graphs are edge minimal 3-connected, hamiltonian, and in general have large numbers of hamilton cycles. We show that for arbitrary real edge costs the travelling salesman problem can be polynomially solved for such a graph, and we give an explicit linear description of the travelling salesman polytope (the convex hull of the incidence vectors of the hamilton cycles) for such a graph.
132 citations
01 Jan 1983
129 citations
TL;DR: The most unique of the newer benzodiazepine derivatives are the ultra-short half-life (oxidised) compounds midazolam, triazol am and brotizol am, which are essentially non-accumulating during multiple dosage.
Abstract: New benzodiazepine derivatives continue to be developed and introduced into clinical use. The pharmacokinetic properties of these newer drugs can best be understood by their categorisation according to range of elimination half-life and pathway of metabolism (oxidation versus conjugation). Clobazam and halazepam are long half-life (and therefore accumulating) anxiolytics metabolised by oxidation. Alprazolam and clotiazepam also are oxidised compounds but have short to intermediate half-life values and therefore produce considerably less accumulation. Temazepam and lormetazepam are hypnotic agents with intermediate half-lives but metabolised by conjugation. The most unique of the newer benzodiazepines are the ultra-short half-life (oxidised) compounds midazolam, triazolam and brotizolam, which are essentially non-accumulating during multiple dosage.
TL;DR: The potential of fast-atom-bombardment in the carbohydrate field was assessed with the aid of unmodified, permethylated, and peracetylated oligosaccharides and glycosphingolipids and pseudomolecular ions were obtained as major ions in the high-mass range.
TL;DR: In this article, the authors present a review of Benzodiazepine Kinetics: Implications for Therapeutics and Pharmacogeriatrics, Vol. 14, No. 2, pp. 251-292.
Abstract: (1983). Benzodiazepine Kinetics: Implications for Therapeutics and Pharmacogeriatrics. Drug Metabolism Reviews: Vol. 14, No. 2, pp. 251-292.
TL;DR: The first 2,3-diphosphabutadiene 6 was derived from the silylated phosphaalkene 1 with hexachloroethane (2) as mentioned in this paper.
Abstract: Die Umsetzung des silylierten Phosphaalkens 1 mit Hexachlorethan (2) ergibt das Chlorphosphaalken 3, welches mit weiterem 1 unter Chlortrimethylsilan-Abspaltung zum ersten 2,3-Diphosphabutadien 6 reagiert. Dieses last sich ebenfalls aus dem persilylierten Diphosphan 4 und 2,2-Dimethylpropionylchlorid (5) darstellen. Die spektroskopischen und Rontgenstrukturdaten von 6 werden diskutiert. Versuche zur Darstellung der 1,4-Diphosphabutadiene 11a, b aus den Organylbis(trimethylsilyl)phosphanen 9a, b und Oxalylchlorid (10) ergeben die entsprechend substituierten 3,4-Diphosphacyclobutene 12a, b. Die Reaktion von 1 mit Phosgen (14a) und dem Isocyaniddichlorid 14b liefert anstelle der erwarteten 1,3-Diphosphabutadiene 16a, b die 1,3-Diphosphacyclobutene 17a, b, deren Struktur durch die Rontgenbeugungsanalyse von 17a gesichert ist. Die Bildung der Cyclobutene 12a, b und 17a, b wird diskutiert.
Low Coordinated Phosphorus Compounds, Diphosphabutadienes
The reaction of the silylated phosphaalkene 1 with hexachloroethane (2) yields the chlorophosphaalkene 3, which reacts with additional 1 under chlorotrimethylsilane elimination to give the first 2,3-diphosphabutadiene 6. This can be prepared as well from the persilylated diphosphane 4 and 2,2-dimethylpropionyl chloride (5). The spectroscopic and x-ray data of 6 are discussed. Experiments for the preparation of the 1,4-diphosphabutadienes 11a, b from the organylbis(trimethylsilyl)phosphanes 9a, b and oxalyl chloride yield the correspondingly substituted 3,4-diphosphacyclobutenes 12a, b. The reaction of 1 with phosgene and isocyanide dichloride 14b yields instead of the expected 1,3-diphosphabutadienes 16a, b the 1,3-diphosphacyclobutenes 17a, b, whose structure is affirmed by x-ray structure determination of 17a. The formation of the cyclobutenes 12a, b and 17a, b is discussed.
TL;DR: In this paper, the authors investigated analytic renormalization procedures for functional integrals, corresponding to field theories defined on compact manifolds, which arise, e.g., from string functionals of the Nambu-Schild-Eguchi type.
Abstract: We investigate analytic renormalization procedures for functional integrals, corresponding to field theories defined on compact manifolds, which arise, e.g., from string functionals of the Nambu-Schild-Eguchi type. Although these models belong to the nonrenormalizable class of quantum field theories, we prove finiteness for a rectangular string shape up to three-loop level, for circular boundary up to two-loop order, and for a variety of graphs in higher order, thus indicating that the result might hold in general. From the explicit calculation of the two-loop approximation we extract the first model-dependent corrections to the $q\overline{q}$ potential or the Casimir effect. The importance of dilation transformations for the properties of the renormalization procedure are investigated. We prove that under certain conditions, forced by symmetry properties, the association of finite values to divergent series is unique, independent of the regularization procedure.
TL;DR: Neutral oligosaccharides isolated from pooled human milk were subjected to fractionation on high-performance thin-layer chromatography plates, Iatrobeads, and reverse-phase chromatography after borohydride reduction and peracetylation and calculated the exact carbohydrate composition from the molecular weight determined by mass spectrometry.
TL;DR: In this paper, all experimental values are expressed in terms of the quadrupole interaction frequency as defined by eq. (1), and the entries are listed order of increasing atomic and mass number of the probe.
Abstract: Data published up to June 1986 have been taken into account. All experimental values are expressed in terms of the quadrupole interaction frequency as defined by eq. (1). The entries are listed order of increasing atomic and mass number of the probe. Energy, spin, half-life and where available the quadrupole moment of the level are given for each probe. Where no reference is given the values for the quadrupole moments have been taken from ref. [310]. The columns of the table contain the following quantities:
TL;DR: In this paper, the oscillatory reaction probability (as a function of energy) of collinear heavy+light-heavy systems (e.g., I+HI→IH+I) is described quantitatively by a semiclassical WKB model.
Abstract: The oscillatory reaction probability (as a function of energy) of collinear heavy+light–heavy systems (e.g., I+HI→IH+I) that has been seen in earlier quantum mechanical reactive scattering calculations is shown to be described quantitatively by a semiclassical WKB model. Because these reactions are highly vibrationally adiabatic they reduce to a two‐state symmetric resonance system (analogous to symmetric charge transfer, e.g., H++H→H+H+) that involves only the phase shifts of the one‐dimensional g (symmetric) and u (antisymmetric) combinations of the two states. Comparisons of the semiclassical and quantum mechanical reaction probabilities over a wide range of energy for the cases I+MuI→IMu+I and I+HI→IH+I show almost perfect agreement. The vibrationally adiabatic symmetric exchange problem is also solved classically (analytically) and is seen to have an interesting relation to the quantum/semiclassical result. The classical reaction probability is also an oscillatory function of energy, although the str...
TL;DR: In this article, an ab initio MRD CI study of the ground and excited states of the C 2 molecule is reported which employs a large DZP AO basis.
TL;DR: In this article, the authors studied the geometric and topological consequences of the existence of a non-trivial Codazzi tensor on a given Riemannian manifold.
Abstract: for arbitrary vector fields X, Y, Z. In this case, the self-adjoint section B of End TM, characterized by g(BX, Y) = b(X, Y), will also be called a Codazzi tensor. The Codazzi tensor b will be called non-trivial if it is not a constant multiple of the metric. The aim of the present paper is to study some geometric and topological consequences of the existence of a non-trivial Codazzi tensor on a given Riemannian manifold. Results of this type were obtained by Bourguignon [3], who proved that the existence of such a tensor imposes strong restrictions on the curvature operator [3, Theoreme 5.1 and Corollaire 5.3] and, as a consequence, obtained the following theorem [3, Corollaire 7.3]: a compact orientable Riemannian four-manifold admitting a non-trivial Codazzi tensor with constant trace must have signature zero. Our main results consist in generalizing these theorems, in particular in seeing what can be said when the assumption on the trace is dropped. In § 2 of this paper we observe that, in the C°° category, every manifold admits a Riemannian metric with a non-trivial Codazzi tensor (Example 7), so that topological consequences may be expected only if some sort of analytic behaviour is assumed. Section 3 is devoted to the particular consequences of the existence of a non-trivial Codazzi tensor B for the structure of the curvature operator (Theorem \):for any point x of the manifold M and arbitrary eigenspaces Vx, V^ ofBx, the span Vx A V^cz A TXM of all exterior products of elements of Vx and V^ is invariant under the curvature operator Rx acting on 2-forms. As a consequence, we obtain in §4 a relation between the eigenspaces of any Codazzi tensor and the Pontryagin forms (Propositions 3 and 4), which, together with an extra argument for the case of a Codazzi tensor having only two distinct eigenvalues (Lemma 1), implies that a compact orientable Riemannian four-manifold (M, g) admitting a non-trivial Codazzi tensor b must have signature zero unless the restriction ofb to some non-empty open subset ofM is a constant multiple ofg (Theorem 2). Another consequence of Proposition 4 is that for any n-dimensional Riemannian manifold with a Codazzi tensor having n distinct eigenvalues almost everywhere, all the real Pontryagin classes are zero (Corollary 3).
21 Aug 1983
TL;DR: The power of deterministic and nondeterministic input driven automata is the same and these automata can recognize e.g. the parenthesis languages and the leftmost Szilard languages.
Abstract: We show that the class of input driven languages is contained in log n space, an improvement over the previously known bound of log2n/ log log log n space [Me 8o]. We also show the power of deterministic and nondeterministic input driven automata is the same and that these automata can recognize e.g. the parenthesis languages and the leftmost Szilard languages (cf. [Me 75], [Ly 76], [Ig 77]).
TL;DR: Amounts of Copper/zinc containing superoxide dismutase have been found in human seminal plasma and in seminal plasma of spermatozoa with a good motility the superoxide Dismutase activity is higher than in those with a low motility.
Abstract: Amounts of Copper/zinc containing superoxide dismutase have been found in human seminal plasma. Superoxide dismutase inhibits the lipid peroxidation in the xanthine oxidase system. In seminal plasma of spermatozoa with a good motility the superoxide dismutase activity is higher than in those with a low motility.
TL;DR: In this paper, a class of special, highly efficient multigrid methods for solving h-discrete elliptic differential equations is introduced, which are characterized by intermediate grids (between the given h-grid and the 2h-grid) and by special fine-to-coarse and coarse-tofine grid transfer techniques.
TL;DR: In this paper, one-dimensional single-channel scattering calculations on an effective potential are used to discuss resonances in collinear reactions and to predict their energetic location almost quantitatively.
TL;DR: In this paper, correlations in charged multiplicity were analyzed using data from the UA5 detector at the CERN SPS collider and both short-range and long-range correlations were observed.
TL;DR: In this paper, the production of π± and K± mesons and of protons and antiprotons ine+e− annihilation has been measured at c.m. energies of W=14, 22 and 34GeV.
Abstract: The inclusive production of π± andK± mesons and of protons and antiprotons ine+e− annihilation has been measured at c.m. energies ofW=14, 22 and 34GeV. Using time of flight measurements and Cerenkov counters the full momentum range has been covered. Differential cross sections and total particle yields are given. At particle momenta of 0.4 GeV/c more than 90% of the charged hadrons are pions. With increasing momentum the fraction of pions among the charged hadrons decreases. AtW=34 GeV and a momentum of 5 GeV/c the particle fractions are approximately π±:K±:p,\(\bar p = 0.55:0.3:0.15\). On average an event atW=34 GeV contains 10.3±0.4π±, 2.0±0.2K± and 0.8±0.1p,\(\bar p\). In addition, we present results on baryon correlations using a sample of events where two or more protons and/or antiprotons are observed in the final state.
TL;DR: Two new pyrrolophenanthridone alkaloids, pratorimine and pratosine, have been isolated and characterized from the bulbs of Crinum latifolium on the basis of comprehensive spectral analyses, chemical transformation and synthesis.
TL;DR: Results indicate that phosphatidylglycerol does not stimulate, and tunicamycin does not inhibit, the transferases themselves; rather, the two opposing effects might relate to carrier-mediated transport, e.g. of nucleotide sugars, across Golgi vesicles.
Abstract: Golgi vesicles were isolated and purified from rat liver, in which the specific activities of glycosyltransferases (e.g. GM3:CMP-NeuAc sialyltransferase, GD3 synthase; GM3:UDP-GalNAc galactosaminyltransferase, GM2 synthase) were 50-60-times enriched relative to microsomes or total homogenate. Synthesis of gangliosides GM2 and GM1 in such Golgi vesicles is, in the absence of any detergents, stimulated 6-fold and 20-fold respectively by phosphatidylglycerol. Other phospholipids like phosphatidylethanolamine and phosphatidylserine are also significantly stimulatory. With 50 micrograms Golgi protein and 1 nmol UDP-GalNAc, optimal stimulation of GM2 synthase was obtained with 20 micrograms of phosphatidylglycerol and 7.5 nmol of the lipid acceptor GM3. Under the same experimental conditions this stimulation exceeds (by about 40%) that obtained with optimal amount (200 micrograms) of the detergent octylglucoside. Phosphatidylglycerol, on the other hand, has virtually no stimulatory activity on the synthesis of ganglioside GD3 either in the presence of Mg2+ or Mn2+, indicating that facilitation by phospholipid of GM3 transport into Golgi vesicles was not the basis of stimulation of GM2 synthesis. Tunicamycin inhibits the synthesis of gangliosides GM2 and GM1 in isolated Golgi vesicles, but only in the absence of detergents. In the presence of phosphatidylglycerol, GM2 synthesis, for example, was inhibited by 60% by 2 micrograms tunicamycin and more than 85% by 10 micrograms tunicamycin, per 50 micrograms Golgi membrane protein. The inhibition was stronger on GM1 synthesis: 85% with 2.5 micrograms of the antibiotic. The dependence on phosphatidylglycerol and the degree of inhibition by tunicamycin of the synthetic activities are strictly dependent on the intactness of the Golgi vesicles: both phenomena become increasingly less evident when the vesicles are pelleted, and frozen and thawed several times, and completely disappear when the vesicles are solubilized by detergents or disrupted by ultrasonication. Furthermore, tunicamycin inhibition is reversible by increased concentration of phosphatidylglycerol. All these results indicate that phosphatidylglycerol does not stimulate, and tunicamycin does not inhibit, the transferases themselves; rather, the two opposing effects might relate to carrier-mediated transport, e.g. of nucleotide sugars, across Golgi vesicles.