Elution of residual ions with etching of heavy ion-injected polyimide

The experiment was carried out to estimate the amount of residual ions after the etching of polyimide irradiated by heavy ions, where etching resulted in a channel of measurable depth in the polyimide. None of the analytical techniques presents each ion separately in etched polyimide containing heavy ions. Activation analysis was used for the irradiated polyimide to see how the injected ions were eluted into the solution by etching. When the irradiated polyimide was etched for only a little longer than the time needed to dissolve a selected range of incident ions, the bulk began subsequently to dissolve. The residual radioactivity in polyimide was found to fall below the limit of detection when the depth of the etched channel appeared 10% deeper than the expected value.     

Extension of secular perturbation theory for asteroids

In this paper the theory of secular perturbations of asteroids with high inclinations and eccentricities (1962) is reviewed and extended analytically for orbits of Kuiper-belt objects and the problem of stellar three bodies consisting of a binary and a distant third body. The theory thus extended seems to be consistent with numerical results published in various papers on subjects like periodic comets, planets of extra-solar systems, star clusters and binaries of black-holes.     

On permutations of wires and states

We characterize a permutation as a sequence of wire-cycle periods and a sequence of state-cycle periods. These sequences are called a wire-sequence and a state-sequence, respectively. A relation between wire-cycles and state-cycles is discussed and some combinatorial problems on cycle periods of permutations are solved. An efficient method for constructing the state-sequence corresponding to a given wire-sequence is also described.     

Error estimates of a Galerkin method for some nonlinear Sobolev equations in one space dimension

Summary A semidiscrete Galerkin finite element method is defined and analyzed for nonlinear evolution equations of Sobolev type in a single space variable. Optimal orderL ^p error estimates are derived for 2p. And it is shown that the rates of convergence of the approximate solution and its derivative are one order better than the optimal order at certain spatial Jacobi and Gauss points, respectively. Also the standard nodal superconvergence results are established. Futher, it is considered that an a posteriori procedure provides superconvergent approximations at the knots for the spatial derivatives of the exact solution.     

Waiakeamide, a Cyclic Hexapeptide from the Sponge Ircinia dendroides(1)

From the sponge, Ircinia dendroides, collected in Indonesia we isolated a new cyclic hexapeptide, waiakeamide (1). Its structure, consisting of three proline residues, two methionine sulfoxides, and one thiazolylphenylalanine, was elucidated by spectral analysis and chemical degradation. Isolation and structural elucidation of waiakeamide is described.     

A novel synthesis of (±)-descarboxyquadrone

The novel synthesis of descarboxyquadrone (3) and its model compound (4) by using the acid-catalyzed rearrangement of [4.3.2]propellanones is described.     

5-Amino-4-sulfanylphthalhydrazide as a chemiluminescence derivatization reagent for aromatic aldehydes in liquid chromatography

5-Amino-4-sulfanylphthalhydrazide (ASPH) was synthesized as a chemiluminescence derivatization reagent for aromatic aldehydes in liquid chromatography (LC). Benzaldehyde, 4-tolualdehyde, 4-chlorobenzaldehyde, 4-formylbenzoic acid, 4-hydroxybenzaldehyde and vanillin were used as model compounds to optimize the derivatization conditions. This reagent, ASPH, reacts selectively with aromatic aldehydes in the presence of sodium sulfite and disodium hydrogenphoshite in acidic medium at 100 degrees C to give the corresponding highly chemiluminescent 2-arylbenzothiazole derivatives. The resulting derivatives generated intense chemiluminescence by reaction with hydrogen peroxide and potassium hexacyanoferrate(III) in alkaline solution. The ASPH derivatives of aromatic aldehydes were separated by reversed-phase liquid chromatography with isocratic elution, and detected chemiluminometrically after mixing with oxidizing agents. The detection limits (signal-to-noise ratio = 3) for aromatic aldehydes are in the range 0.2-4.0 fmol for a 20-microl injection volume. Currently, the method is not effective for aliphatic aldehydes because of interfering LC peaks.