Preparation and certification of the new reference materials; plastics (disk form, JSAC 0621-0625) for determination of mercury using x-ray fluorescent analysis.

The Japan Society for Analytical Chemistry has developed some new plastic certified reference materials (CRMs) for the analysis of mercury in polyester disks using XRF analysis. These CRMs (named as JSAC 0621-0625) were prepared by casting polyesters including a toluene solution of organometallic compounds as a standard. Concentrations of the five levels of mercury ranged from 0 to 250 mg/kg. Homogeneity tests of prepared disks had shown excellent results. Interlaboratory comparison study for the certification was performed by 15 laboratory participants. The z-scores in robust statistical method was applied for the evaluation of outliers. The certified values were assigned after discarding outliers. The uncertainties of certified values were determined as the confidence levels of 95%.     

FLUORESCENCE OF 1-DIMETHYLAMINONAPHTHALENE-5-SULFONATE AND PYRENE-1-SULFONATE CONJUGATED TO BACTERIORHODOPSIN

Abstract— Two fluorescence probes, 1-dimethylaminonaphthalene-5-sulfonylchloride and pyrene-1-sulfonylchloride, were conjugated to the protein in purple membrane and fluorescence intensity and anisotropy were measured as a function of temperature. The anisotropy of the 1-dimethyl-aminonaphthalene-5-sulfonate conjugate showed a characteristic temperature dependence, in which, the anisotropy is constant at 0.22 ± 0.01 until 25-30°C and decreases above 30°C. The fluorescence intensity, however, varies linearly with temperature. These results imply that the transition is due to bacteriorhodopsin in the trimer.     

Novel ring transformation reactions of xanthine derivatives

The novel ring transformation reactions were found in the reactions of 1,3,7,9-tetra-alkyl-8,9-dihydroxanthines and acetylenic compounds. The reaction of the dihydroxanthine with DMAD gave a propellane type compound and with methyl propiolate afforded the similar type compound and a pyrimido[4,5-b]diazepine derivative. The mechanism of these reactions was also discussed.     

Preparation of crystalline polyamides by the alternating copolymerization of aziridines and cyclic imides

The copolymerization of aziridines and cyclic imides was studied. Aziridines copolymerized alternately with cyclic imides to give crystalline polyamides. Ethylenimine and succinimide copolymerized to nylon 2,4, melting near 300°C., without any catalyst. Similarly, the corresponding crystalline polyamides were obtained from the systems of 1,2-propylenimine–succinimide, ethylenimine–glutarimide, and ethylenimine–phthalimide. The copolymerization of aziridines and cyclic imides in the presence of BF₃OEt₂ gave a copolymer which was rich in aziridine units, whereas, the addition of triethylamine had no influence on the copolymer composition. A mechanism of copolymerization was proposed based on the facts that N-tetramethylenesuccinamide was obtained by the reaction of pyrrolidine and succinimide, N-acetylethylenimine reacted with acetamide to yield N,N′-diacetylethylenediamine and that the rate of this copolymerization was dependent on the electrophilicity of imide.     

Uniform convexity of ψ-direct sums of Banach spaces

Let X and Y be Banach spaces and ψ a continuous convex function on the unit interval [0,1] satisfying certain conditions. Let X⊕_ψY be the direct sum of X and Y equipped with the associated norm with ψ. We show that X⊕_ψY is uniformly convex if and only if X,Y are uniformly convex and ψ is strictly convex. As a corollary we obtain that the ?_p,q-direct sum (not p=q=1 nor ∞), is uniformly convex if and only if X,Y are, where ?_p,q is the Lorentz sequence space. These results extend the well-known fact for the ?_p-sum . Some other examples are also presented.     

Generation of a squeezed vacuum resonant on a rubidium D1 line with periodically poled KTiOPO4

We report the generation of a continuous-wave squeezed vacuum resonant on the Rb D1 line (795 nm) using periodically poled KTiOPO4 (PPKTP) crystals. With a frequency doubler and an optical parametric oscillator based on PPKTP crystals, we observed a squeezing level of -2.75+/-0.14 dB and an antisqueezing level of +7.00+/-0.13 dB. This system could be utilized for demonstrating storage and retrieval of the squeezed vacuum, which is important for the ultraprecise measurement of atomic spins as well as quantum information processing.