Trace element determination in soft tissues of marine bivalves by activation analysis

Trace elements in soft tissues of marine bivalves were determined by neutron activation analysis (NAA) and photon activation analysis (PAA). Elemental levels of Ag, As, Br, Co, Cu, Fe, I, Mn, Ni, Rb, Se, and Zn in the organs of giant ezoscallos, rock oysters, and giant crams were obtained. The metal-bound proteins were extracted from the mantles and hepatopancreases of rock oysters. By irradiating the fraction obtained by HPLC gel chromatography, we found the possibility for the existence of an Ag bound protein in the mantles.     

Approximation algorithms for combinatorial fractional programming problems

We are concerned with a combinatorial optimization problem which has the ratio of two linear functions as the objective function. This type of problems can be solved by an algorithm that uses an auxiliary problem with a parametrized linear objective function. Because of its combinatorial nature, however, it is often difficult to solve the auxiliary problem exactly. In this paper, we propose an algorithm which assumes that the auxiliary problems are solved only approximately, and prove that it gives an approximate solution to the original problem, of which the accuracy is at least as good as that of approximate solutions to the auxiliary problems. It is also shown that the time complexity is bounded by the square of the computation time of the approximate algorithm for the auxiliary problem. As an example of the proposed algorithm, we present a fully polynomial time approximation scheme for the fractional 0–1 knapsack problem.     

Routine determination of light elements by charged-particle activation analysis

Bombardment conditions, chemical separation, and counting method were examined for routine determination of carbon, nitrogen, and oxygen in various matrices by charged-particle activation analysis with respect to reliability, reproducibility, simplicity, and rapidity. A system was then set up for trustworthy measurement of these elements.     

p-Benzoquinone-2,3-dicarboxylic anhydride as highly reactive and versatile electron-accepting dienophile

Pericyclic reactions of p-benzoquinone-2,3-dicarboxylic anhydride(PBA) with homo-dienne and conjugated medium-ring polyenes have been examined. The high peri- and stereospecificity observed with dienes is explained using the frontier orbital model where the diene HOMO-PBA LUMO interaction predominates.     

Asymmetriche Synthese unter Verwendung von Poly(5-benzyl-L-glutamat) als Katalysator

Ohne Zusammenfassung     

A phenomenological analysis on γp → π+n, πOp below 1.2 GeV

A phenomenological partial-wave analysis on γp → π⁺n and π^Op reactions has been performed in the energy range 0.25–1.2 GeV with available data, laying special emphasis on the polarization and asymmetry data. A good fit has been obtained.     

Trapping of positive muons by vacancies in non-stoichiometric compounds

A direct evidence for trapping of positive muons by vacancies was found by using the longitudinal field method., 65.5 at. %Cu-34.5 at. %Al, 51at. %Al-49at. %Ni and 52 at. %Al-48at. %Ni polycrystalline samples were studied. The forward/backward asymmetry was measured as a function of time at room temperature changing the magnetic field from 0 to 70 Oe. At H=0, a relaxation function of Kubo-Toyabe type was found. Analysing the data, it was found that positive muons are trapped by vacancies in these materials.