Gravimetric determination of palladium with biguanide sulfate

1986

Abstract Biguanides are interesting reagents for the determination of palladium owing to their solubility, chemical resistance, and selectivity in moderately acidic solutions. A procedure for the gravimetric determination of palladium(II) in the form of Pd(HL)2SO4, where HL = biguanide, is proposed and the conditions of precipitation, treatment of the precipitate, precision, accuracy, and selectivity of the procedure are discussed.

Impact excitation of 42 P-potassium by polarized electrons

1986

The present work investigates the 42 P impact excitation of potassium by longitudinally polarized electrons. Exchange scattering causes a polarization transfer from the primary electron beam to the ensemble of excited atoms which results in a non zero circular polarization of the fluorescence light emitted in foreward direction. The experimental values of light polarization agree well with values calculated using close coupling data of Moores.

Significance of ultrasound for the diagnosis of hypertrophic pyloric stenosis

1986

The sonographic features of hypertrophic pyloric stenosis (HPS) were evaluated in a 5-year prospective study (1981–1985) at the University Clinic of Pediatric Surgery in Mainz. In 37 cases real-time ultrasound was performed preoperatively to measure muscle thickness, diameter, and length of the pylorus; the recorded values were compared with those of a control group. Muscular wall thickness proved to be the most reliable parameter, while pyloric canal length was the most difficult measurement to obtain. Diameter alone was not adequate to establish the sonographic diagnosis, which depends on the individually and functionally different luminal width and submucosal thickness. Significant sonog…

Topographical geometric factors governing the biological activities of methomyl derivatives on binding receptors of maize mitochondria

1986

Abstract The topographical study of the binding receptors of T and N mitochondria was undertaken with methomyl derivatives acting as molecular probes. The two biological activities related to topography and geometric isomerism are distinguishable from the receptor sites of T and N mitochondria.

Statistical Mechanics of the Sine-Gordon Equation

1986

We give two fundamental methods for evaluation of classical free energies of all the integrable models admitting soliton solutions; the sine-Gordon equation is one example. Periodic boundary conditions impose integral equations for allowed phonon and soliton momenta. From these, generalized Bethe-Ansatz and functional-integration methods using action-angle variables follow. Results for free energies coincide, and coincide with those that we find by transfer-integral methods. Extension to the quantum case, and quantum Bethe Ansatz, on the lines to be reported elsewhere for the sinh-Gordon equation, is indicated.

Critical wetting with short-range forces: Is mean-field theory valid?

1986

Fructose 2,6-bisphosphate as a signal for changing from sugar to lipid oxidation during flight in locusts

1986

AbstractFlight in locusts is initially powered mainly by carbohydrate but if flight is to be sustained, as in migration, the animals have to utilize fat as the predominant fuel. The molecular basis of this metabolic switch has not been identified. Fructose 2,6-bisphosphate is a potent activator of 6-phosphofructokinase (EC 2.7.1.11) purified from locust flight muscle. After the first few minutes of flight in the locust the concentration of fructose 2,6-bisphosphate in the flight muscle falls dramatically, which should lead to a decrease in the activity of 6-phosphofructokinase as part of the mechanism to conserve carbohydrate during prolonged flight.

Matkakuvaus Neuvostoliitosta

1986

Los impresos científicos españoles de los siglos XV y XVI: inventario, bibliometría y thesaurus. Vol. IV

1986

pp. 127

Inequalities for character degrees of solvable groups

1986

THE GOLDMAN CONSTANT FIELD ASSUMPTION - SIGNIFICANCE AND APPLICABILITY CONDITIONS

1986

Ionic transport phenomena in simple, porous membranes can be approximately represented by the Nernst-Planck flux equations and Poisson's equation. In order to solve this set of equations for each particular case, the Goldman constant field assumption is one of the most widely used. In the present paper the significance and the applicability conditions of the above hypothesis is critically examined. and the particular situations where it is exact are shown. These conditions are later verified by solving numerically the electrodiffusion equations. The analysis carried out shows that some of the earlier studies based on asymptotic expansions and numerical solutions should be partially revised.

Complex powers of elliptic pseudodifferential operators

1986

The aim of this paper is the construction of complex powers of elliptic pseudodifferential operators and the study of the analytic properties of the corresponding kernels kS (x,y). For x=y, the case of principal interest, the domain of holomorphy and the singularities of kS (x,x) are shown to depend on the asymptotic expansion of the symbol. For classical symbols, kS (x,x) is known to be meromorphic on ℂ with simple poles in a set of equidistant points on the real axis. In the more general cases considered here, the singularities may be distributed over a half plane and kS (x,x) can not always be extended to337-2. An example is given where kS (x,x) has a vertical line as natural boundary.

Reliability Analysis of Systems Containing Complex Control Loops

1986

Abstract Many Process Plants employ complex control and trip systems to improve process safety. Reliability prediction requires determination of the failure mechanisms followed by quantification of the failure rates. The fault tree technique is often used for reliability prediction. Fault tree construction is a skilled task and can be complex for systems containing multiple protective devices. The paper compares 3 approaches to the problem of fault tree construction. The problems of quantification and common mode failure is also considered.

Das kleinste Ree-Unital

1986

Multisteroid analysis after DST in depressed patients — A controlled study

1986

Abstract 111 consecutively admitted in-patients with a depressive syndrome received a dexamethasone suppresion test (DST) after all known factors which might confound the test results had been carefully excluded. Plasma concentrations of cortisol, corticosterone and dexamethasone were compared with several diagnostic evaluations (RDC, DSM-III, ICD-9) in a controlled study. The positive predictive value of nonsuppressed corticosteroid levels was only moderate for each diagnostic category. Diagnostic specificities were 84.6% for major depression, endogenous subtype (RDC), 71.2% for melancholia (DSM-III) and 86.8% for endogenous depression (IDC-9) when using a post-DST cortisol value above 50 …

Size-dependent photoemission shifts in small metal clusters

1986

Density-functional calculations of the change in self-consistent-field energy ( Delta SCF) type are reported for core-level photoemission shifts in small metal spheres. The results for the atom-in-jellium vacancy model show that the binding energies are increased from bulk-metal values, but the photoemission shifts show considerable oscillations as a function of cluster size.

false

1986

A procedure is described for the preparation of a block copolymer with A-B-A sequences in which ω-ω′-dihydroxy-poly-(ethylene glycol) is inserted between two polymeric monoacidic chains of polycaproamide and bonded to them by means of ester links. The resulting material was characterized. The copolymer is isomorphous with the polycaproamide. Thermal treatments induce a crystalline transition γ α as in polycaproamide. The influence of the moisture content on the glass transition temperature and on the storage modulus is discussed. Ein Verfahren zur Herstellung eines Blockcopolymers mit A-B-A-Sequenzen wird beschrieben. In dem Copolymer ist ω-ω′-Dihydroxy-polyethylenglycol uber Esterbindungen…

Who profits from the public funding of education : a comparison world regions

1986

International audience

Rat CNS neurons are not yet programmed to shorten their chromatin repeat length at the end of fetal neurogenesis.

1986

Neurons from rat fetal cerebral hemispheres were grown in a synthetic medium (Maat medium), as previously described, for different periods of time. The repeat length of their chromatin was determined by micrococcal nuclease digestion and compared with that of neurons isolated from postnatal rat brain of corresponding ages. In contrast to the in vivo situation, we found that neurons, dissociated at the 16th gestational day and cultured in vitro, did not undergo the shortening of their chromatin repeat, thus indicating that, at the end of their mitotic cycles, they are not yet programmed to this event. © 1986.

Ouabain enhances release of acetylcholine in the heart evoked by unilateral vagal stimulation.

1986

The aim of the study was to elucidate peripheral effects of ouabain on the parasympathetic innervation of the heart, effects that could contribute to the experimentally and clinically well established “vagal effect of cardiac glycosides”. The experiments were carried out with ouabain concentrations of 3×10−7 and 10−6 mol/l, which were considered “therapeutic”, as they increased force of contraction and did not elicit arrhythmias in incubated chicken atria. In atrial preparations of chickens and guinea-pigs the negative chronotropic and inotropic effects of acetylcholine (ACh) were not altered by 3×10−7 mol/l ouabain. Resting efflux of ACh from perfused chicken hearts was increased by ouabai…

Hydrogen bond studies on n-pentanol and 2-methyl-2-butanol by Raman spectroscopy

1986

Polarized Raman spectra of n-pentanol and its isomer 2-methyl-2-butanol are obtained in the liquid phase near the melting points and at superheated temperatures. The measurements are performed in the intramolecular O-H stretching region. Our analysis of the Raman data provides an interpretation of the spectral features in terms of symmetric O-H bands, originated by various degrees of intermolecular coupling, for which mechanism is different for the two isomers. Temperature dependence of the spectra is also discussed in terms of available structural and dynamical models for these H-bonded liquids.

false

1986

Polyhydrogenomethylsiloxanes ayant la meme paire de groupes lateraux mesogenes mais un bras ecarteur different

Über polygermane

1986

Abstract The optimum conditions for the synthesis of the trigermanes Ge3Ph8 and Ge3Me2Ph6 according to R2GeCl2 + 2 Ph3GeAk (Ak = Li, K) in HMPT have been determined. The main difficulty is to repress a nucleophilic attack of Ph3Ge− at newly formed GeGe bonds. The mass spectrum of Ge3Me2Ph6 shows rearrangements of the GePh3 and Ph/Me groups. The 13C NMR phenyl signals of di-, tri- and tetra-germanes are nearly identical. Ge3Ph8 and Ge4Ph10 transform to the plastically-crystalline state before melting (ΔH 45.3 and 54.9 kJ mol−1). The crystal structure of Ge3Me2Ph6 has been determined. The molecule has C2 symmetry (GeGe 242.9(1) pm, GeGeGe 120.3(1)°).

Photochemie des 1,3‐Distyrylbenzols — Ein neuer Weg zu syn ‐[2.2](1,3)Cyclophanen

1986

Finite linear spaces in which any n-gon is euclidean

1986

Abstract An n-gon of a linear space is a set S of n points no three of which are collinear. By a diagonal point of S we mean a point p off S with the property that at least two lines through p intersect S in two points. The number of diagonal points is called the type of S. For example, a 4-gon has at most three diagonal points. We call an n-gon euclidean if (roughly speaking) it contains the maximal possible number of 4-gons of type 3. In this paper, we characterize all finite linear spaces in which, for a fixed number n ⩾ 5, any n-gon is euclidean. It turns out that these structures are essentially projective spaces or punctured projective spaces.

Fluoreszenz‐Untersuchungen an styrylsubstituierten Benzolen

1986

Die Fluoreszenz-Abklingzeiten der stilbenartigen Verbindungen 1 – 4 zeigen, das die mittleren Lebensdauern dieser Molekule im elektronisch angeregten Singulettzustand um rund zwei Zehnerpotenzen hoher sind als bei trans-Stilben selbst. Anhand von UV-Absorptions-und Anregungsspektren wird das auf einen neu gefundenen S1-Zustand zuruckgefuhrt, der einem verbotenen Ubergang S0 S1 auf der langwelligen Seite der intensiven Absorption entspricht. Investigations on the Fluorescence of Styryl-substituted Benzenes Fluorescence decay measurements of the stilbene-like compounds 1 – 4 demonstrate that the average lifetimes of these molecules in the electronically excited singlet state are about 102 tim…

Compounds of tungsten(VI) with citric acid: A spectrophotometric, polarimetric and hydrogen-1, carbon-13 N.M.R. study of the formation and interconve…

1986

Tungsten(VI)-citrate complexes, which occur in aqueous solution, were studied by polarimetric and absorbance measurements. The pH of the medium is the principal variable controlling complex formation and interconversion equilibria. At high pH (>6), the stable complexes are monomers with 1∶2 and 1∶1 stoichiometry, depending on the tungsten(VI)-citrate ratio, while at lower pH two different dinuclear complexes are formed. The intervals of existence of these species with the pH, the number of equivalents of acid necessary for their formation, as well as the conditional stability constant, have also been calculated. The structure of these compounds have been investigated by1H and13C-n.m.r. spec…

Antibakterielle wirkstoffe. IX . Die aminomethinylierung im system des 3-methyi-1-(4-nitrophenyl)-2-pyrazolin-5-ons

1986

Die mit Hilfe von s-Triazin (1) durchgefuhrte Aminomethinylierung von 3-Methyl-1-(4-nitrophenyl)-2-pyrazolin-5-on (2) fuhrt zu dem Aminomethinylierungsprodukt 4 und dem C-Rubazonsauretypus 5. In den zur Untermauerung der erhaltenen Strukturen aufgenommenen Massenspektren treten als charakteristische Fragmente von 4 das Pyrazolo[4,3-d]isoxazolyliumion 6 (m/e 245), p-Benzochinonmonoiminylkation (m/e 106) und Mthylenaminophenylkation (m/e 104) auf. The aminomethinylation of 3-methyl-l-(4-nitrophenyl)2-pyrazolin-5-one (2) by means of s-triazine (1) leads to the aminomethinylation product 4 and the C-rubazoic acid type 5. The mass spectra supporting the structures obtained exhibit the pyrazolo[4…

Zur protonenkatalysierten elektrophilen substitution von 2,3-dimethylindol mit arylaldehyden: C6-regioselektivität am indol-gerüst

1986

The proton catalyzed reaction of 2,3-dimethylindole (1) with several arylaldehydes 2 yields the 6,6′bisindolylarylmethanes 5 regioselectively. No mechanistic information about the predominant attack of the aldehydes on the indole nucleus is obtained, because the reaction proceeds too fast to control. The electron-rich aldehydes, 2,4,6-trimethoxybenzaldehyde and indole-3-carbaldehyde, yield exclusively the 6,6′,6″-trisin-dolylmethane 9. The constitutions of all isolated methanes were elucidated by 400 MHz 1H-nmr spectroscopy.

Photodecomposition of adsorbed ethanoic acid over silica gel catalyst in a flow system

1986

Abstract The photodecomposition of ethanoic acid adsorbed on silica gels from various sources was studied at wavelengths greater than 300 nm. The experiments were carried out in a flow apparatus. A few photoreactivity tests using acetone or ethanol were also performed. The photodecomposition of ethanoic acid and acetone produced mainly carbon dioxide and methane, in the ratio 2:1, and traces of ethane and methanol. Adsorbed ethanol was not affected at all by the radiation. Infrared and UV-vis reflectance spectra of ethanoic acid adsorbed on silica gels as well as UV-vis reflectance spectra of acetone and ethanol adsorbed on silica gels were recorded. The spectra show the presence of a varie…

Improved stability of black lipid membranes by coating with polysaccharide derivatives bearing hydrophobic anchor groups

1986

Abstract Black lipid membranes were coated with modified polysaccharides bearing hydrophobic palmitoyl and cholesteryl moieties. The changes in membrane structure were investigated using dipicrylamine, a lipophilic ion, as membrane probe. The kinetics of ion transport through the black lipid membranes were studied using the charge pulse relaxation technique. With this technique it was found that it is possible to detect the insertion of the hydrophobic anchor groups of the polysaccharides into the membrane bilayer. As a result of the surface coating, these membranes exhibit a drastically increased long-term stability.

Histopathology and Classification of Renal Cell Tumors (Adenomas, Oncocytomas and Carcinomas)

1986

The term renal cell tumors (adenomas and carcinomas) subsumes the tumors deriving from the uriniferous tubule epithelium of the kidney. Precise analysis shows that the renal cell tumors display different cell types which build up the individual tumor alone or in combination with each other. Three categories of basic elements are distinguished in the characterization of renal cell tumors: Cytological elements = tumor cell types: Clear, chromophobe, chromophilic (basophilic, eosinophilic), oncocytic, spindle-shaped/pleomorphic. Histological elements = growth patterns: Compact, acinar (nest-like), tubulopapillary (tubular, papillary), cystic. Cytological grading of malignancy: G I, G II, G III…

Survival and prognostic indicators in compensated and decompensated cirrhosis

1986

Six-year survival of cirrhosis was assessed in a series of 1155 consecutive patients (751 men, 404 women). Among the men, 33% were alcoholics and 18% were HBsAg positive; corresponding figures for the women were 15% and 6%, respectively. Features of decompensation at first presentation were observed in 63% of the patients. Six-year survival was 54% in compensated and 21% in decompensated patients. No significant differences in survival were found between alcoholics and nonalcoholics. Leading causes of death were liver failure (49%), hepatocellular carcinoma (22%), and bleeding (13%). The prognostic role of 21 variables was evaluated separately in compensated and decompensated patients by th…

Dipolar and Quadrupolar Freezing in(KBr)1−x(KCN)x

1986

Dipolar and quadrupolar susceptibility measurements are reported for the molecular glass system ${(\mathrm{KBr})}_{1\ensuremath{-}x}{(\mathrm{KCN})}_{x}$ covering a wide range of frequencies. The results allow a direct comparison of the dipolar and quadrupolar anomalies and demonstrate unambiguously that the freezing in of the dipolar and quadrupolar degrees of freedom occurs at different temperatures.

Flavor Changing Yukawa Coupling in the Standard Model and Muon Polarization in KL-->mumu¯

1986

The muon longitudinal polarization P/sub L/ in K/sub L/..--> mu..mu-bar decay is investigated in the standard model. The induced s-bardH vertex responsible for P/sub L/ turns out to be unexpectedly ''large.'' The measurement of P/sub L/ above approx.10/sup -3/ will, therefore, be a signal of the existence of a rather light Higgs boson (M/sub H/< or approx. =10 GeV). It is also shown that the mechanism of gauge-dependence cancellation between Higgs-boson-exchange and box diagrams works even in the standard model.

Stereoselektive Glycosylierung von Steroidalkoholen mit 2,3,4,6-Tetra-O-privaloyl-α-D-glucopyranosylbromid (Pivalobromglucose) und 2,3,4,6-Tetra-O-(o…

1986

Steroidalkohole verschiedener Struktur, deren Hydroxyfunktionen aus elektronischen und sterischen Grunden in ihrer Reaktivitat differieren und die daruber hinaus empfindliche Gruppierungen enthalten, werden mit 2,3,4,6-Tetra-O-pivaloyl-α-D-glucopyranosylbromid (1) selektiv und effektiv in β-Glucoside ubergefuhrt. Dank des lenkenden Einflusses des 2-O-Pivaloyl-Substituenten wird eine Orthoesterbildung bei den Koenigs-Knorr-Reaktionen stark unterdruckt. Mit dem o-Toluoylrest als Hydroxyschutzgruppe wird diese Lenkung nur in geringem Mas erreicht. Stereoselective Glycosylation of Steroid Alcohols Using 2,3,4,6-Tetra-O-pivaloyl-α-D-glucopyranosyl Bromide (Pivalobromoglucose) and 2,3,4,6-Tetra-O…