New extremal doubly-even [64, 32, 12] codes

In this paper, we consider a general construction of doubly-even self-dual codes. From three symmetric 2-(31, 10, 3) designs, we construct at least 3228 inequivalent extremal doubly-even [64, 32, 12] codes. These codes are distinguished by their K-matrices.     

Mössbauer study of the after-effects of the converted isomeric transition in 119mSn in frozen solutions of SnCl2 and in solid adducts of SnCl2 and SnBr4 with organic donor molecules

As an after-effect of the converted isomeric transition in ^119mSn, about 30% yield of the oxidised aliovalent species Sn⁴⁺ was observed in Mössbauer spectra of frozen solutions of ^119mSnCl₂ in organic solvents such as dimethyl sulphoxide and methanol. On the other hand, the reduced aliovalent species Sn²⁺ was observed in the emission spectra of crystalline solid adducts of ^119mSnBr₄ with dimethyl sulphoxide and other donors. As a mechanism for the stabilization of the oxidized aliovalent species observed in the emission spectra of the frozen solutions, it is proposed that the electrons released by Auger processes are trapped in imperfections of the glassy matrices of the medium. On the other hand, a possible mechanism for the formation of reduced species from adducts of ^119mSnBr₄ is that reducing radicals are formed by dissociative electron capture in autoradiolysis of the closest ligands within the molecules. The large yields of the oxidized aliovalent species Sn⁴⁺ observed in the emission spectra of the crystalline solid adducts of ^119mSnCl₂ with dimethyl sulphoxide, pyridine N-oxide, and pycoline N-oxides are also to be understood in terms of dissociative electron capture in autoradiolysis of the ligand.     

Substituent effect on the acetolysis of neophyl p-bromobenzenesulfonates

The substituent effect on the acetolysis of neophyl brosylates was analyzed successfully based on the analysis method of Yukawa-Tsuno. The basic concept of this method was strongly supported.     

Cucurbitadienol synthase, the first committed enzyme for cucurbitacin biosynthesis, is a distinct enzyme from cycloartenol synthase for phytosterol biosynthesis

Three oxidosqualene cyclase (OSC) cDNAs (CPX, CPQ, CPR) were cloned from seedlings of Cucurbita pepo by homology based PCR method. Their open reading frames were expressed in lanosterol synthase deficient (erg7) Saccharomyces cerevisiae strain GIL77. Analyses of in vitro enzyme activities and in vivo accumulated products in the transformants demonstrated that CPQ and CPX encode cucurbitadienol and cycloartenol synthases, respectively. These results indicated the presence of distinct OSCs for cycloartenol and cucurbitadienol synthesis in this plant.     

Effect of dual frequency on sonochemical reaction rates

An ultrasonic reactor that combined a standing-wave-type transducer and a horn-type emitter was constructed and the ultrasonic frequency of the standing-wave-type transducer was varied and the sonochemical reaction rates were estimated. The synergy effect was observed below 100 kHz. In order to consider the mechanism of effect of synergy, the acoustic noise, the sonochemical luminescence and the bubble behavior in the reactor were investigated. The frequency spectrum of acoustic noise indicated that the synergy effect came from the increase of number of cavitation bubbles.     

Catalytic flow-injection determination of reactive iron in non-acidified water samples.

A flow-injection determination method was proposed for the speciation of reactive species of iron in non-acidified water samples. Iron was determined by the spectrophotometric monitoring of the iron-catalyzed oxidation of o-phenylenediamine with hydrogen peroxide. The reactive iron was characterized as Fe3+ and Fe(III)Li(3-in), where i = 1 or 2 for a unidentate ligand and i = 1 for a bidentate ligand (L(n-)) from the chemical equilibria of hydroxo, oxalato and fluoro Fe(III) complexes. A useful parameter was also proposed to check the reliability of the determination when suffering the adsorption of iron on the inner wall of a PTFE tube of a flow-injection system. Under the optimized FIA condition and by measuring the peak height, a linear calibration curve of iron was obtained up to 0.1 mg L(-1) with a detection limit of 0.1 microg L(-1). The proposed method was successfully applied to the speciation of reactive and unreactive iron in tap- and river-water samples.     

Plane curves whose tangent lines at collinear points are concurrent

We are interested in a particular geometry of plane curves in characteristicp>0, which was inspired by Thas's article [13]. We will prove that any plane curve of degree > 2 whose tangent lines at collinear points are concurrent is either a strange curve or projectively equivalent to the Fermat curve of degreeq + 1, whereq is a power ofp.