Electrical properties of bilayer lipid membranes containing iodine and iodide,investigated by cyclic voltammetry

The conduction properties of lecithin bilayer membranes in iodine-containing solutions are examined from a potentiodynamic experimental approach. Voltammetric data obtained by using a variety of forms (derived from charge-transfer type interactions) of iodide implicate the triiodide ion as the charge carrier accounting for the diffusion-limited voltammetric response whereas the charge transport of iodide seems to be limited by transmembrane diffusion. The data are used to support one of the many proposed mechanisms for conductance of iodide in membranes.     

Platinum-catalyzed intramolecular hydroamination of unactivated olefins with secondary alkylamines

Reaction of benzyl-2,2-diphenyl-4-pentenylamine with a catalytic 1:2 mixture of [PtCl2(H2C=CH2)]2 (2.5 mol %) and PPh3 in dioxane at 120 degrees C for 16 h led to isolation of 1-benzyl-2-methyl-4,4-diphenylpyrrolidine in 75% yield. A number of gamma- and delta-amino olefins underwent intramolecular hydroamination to form the corresponding pyrrolidine derivatives in moderate to good yield. The reaction displayed excellent functional group compatibility and low moisture sensitivity.     

The role of MgO in the binding of SO<Subscript>2 </Subscript>by lime-containing materials

Summary The results of investigation of MgO participation in the binding of SO₂ with lime-containing materials as sorbents are presented. Experiments of SO₂ binding into solid phase using model samples of reactive grade MgO and CaO varying the mole ratio of MgO/CaO from 9:1 to 1:9 were carried out. Besides, dolomite and limestone samples with different MgO/CaO mole ratio (from 1.24 to 0.13) and samples of ashes formed at combustion of Estonian oil shale (containing 35-40% of carbonates) and its semicoke were studied Initial samples, intermediate and final products were subjected to chemical, IR-spectroscopy, X-ray and BET specific surface area analyses. The results of the present study confirmed the active participation of MgO in the binding of SO₂ into the solid phase. In addition to CaSO₄ the formation of Ca,Mg-double sulphate CaMg₃(SO₄)₄ and -MgSO₄ was observed. The presence of CaMg₃(SO₄)₄ was fixed in a large temperature range 400-900°C and that of -MgSO₄ in between 500-700°C. The optimum temperature range for formation and durability of CaMg₃(SO₄)₄ was 700-800°C.     

Low-energyπK-scattering

A self-consistent calculation of thes- andp-wave resonance inπK-scattering is attempted using as input the exchanged resonances themselves and the exchange of a?-meson. While this approximation to the left-hand cut fails in thes-wave problem it produces ap-wave resonance but for a much too strong?-coupling. Position and width depend very sensitively on the inelastic region. Suppressing this region by a subtraction at threshold the subtraction constant can be adjusted to yield the observed position. The corresponding width is close to the experimental values for reasonable?-coupling.     

Selfconsistent calculation of the 11- and 33-amplitude in the low-energy π-N-scattering

A self-consistent calculation of the masses of the nucleon and the 33-resonance, theπN-coupling constant and the resonance width is made. By using a simplified version of theN/D-method the consistency equations are reduced to algebraic equations. Therefore selfconsistency can be obtained at once for both partial waves. In order to suppress the high energy contributions a second subtraction at threshold is made. The thereby introduced subtraction constants are connected with the 11- and 33-scattering lengths which are known from experiment.     

Prediction of the one pion exchange contribution to the processπ − p→π − pω with the help of the Veneziano model

The one pion exchange contribution to the differentialπ ^? p→π ^? pω cross-section is calculated assuming that theπ→πω amplitude associated with one of the vertices is described by the Veneziano formula, and that only a trivial dependence of the latter on the mass of the exchanged pion needs to be taken into account. The remaining unknown overall constant is then fixed by considering the decayω→3π. A rough comparison with preliminary data from a 16 GeV/cπ ^? p experiment shows that the one pion exchange model could possibly describe the reactionπ ^? p→π ^? pω forπω masses above 1.4 GeV.     

Characteristic polynomials of symmetric matrices III: some counterexamples

When is a monic polynomial the characteristic polynomial of a symmetric matrix over an integral domain D? Known necessary conditions are shown to be insufficient when D is the field of 2-adic numbers and when D is the rational integers. The latter counterexamples lead to totally real cubic extensions of the rationals whose difierents are not narrowly equivalent to squares. Furthermorex³-4x+1 is the characteristic polynomial of a rational symmetric matrix and is the characteristic polynomial of an integral symmetric p-adic matrix for every prime p, but is not the characteristic polynomial of a rational integral symmetric matrix.     

A novel approach to the solution of boundary-layer problems

By replacing a differential equation boundary-layer problem by its discrete lattice equivalent we are able to treat the resulting equation as a regular perturbation problem. We obtain the solution on the lattice as a regular perturbation series in inverse powers of the lattice spacing. To obtain the answer to the continuum problem we extrapolate the solution to the lattice problem to zero lattice spacing. This extrapolation, which is a Padé-like procedure, yields good numerical results for a wide range of problems.