Nongauge local symmetry in gravity

It is shown that there exists a class of nongauge local symmetry in gravity. It is the combination of the known gauge symmetries and _{off shell} transformation. _{off shell} is the transformation which vanishes on shell. _{off shell} invariance imposes some restriction on model Lagrangians besides gauge symmetry, though it does not reduce the physical degrees of freedom.     

Selective determination of ammonium ions by high-speed ion-exclusion chromatography on a weakly basic anion-exchange resin column

This paper describes an ion-exclusion chromatographic system for the rapid and selective determination of ammonium ion. The optimized ion-exclusion chromatographic system was established with a polymethacrylate-based weakly basic anion-exchange resin column (TSKgel DEAE-5PW) as the separation column, an aqueous solution containing 0.05 mM tetramethylammonium hydroxide (pH 9.10) as eluent with conductimetric detection for the analyte determination. Under the optimum chromatographic conditions, ammonium ion was determined within 2.3 min with a detection limit (S/N=3) better than 0.125 microM. Ammonium ion in rain and river waters was precisely determined using this ion-exclusion chromatographic system.     

Synthesis of 4-hydroxy-3-triftuoromethylpyrazoles

Trifluoroacetaldehyde hydrazones are condensed with glyoxals to give 4-hydroxy-3-trifluoromethylpyrazoles, the reaction offering a novel route to 4-hydroxypyrazoles carrying trifluoromethyl group. The 4-hydroxyl group was easily converted to its derivatives by the reaction with various electrophiles.     

Determinations of citric acid by differential pulse polarography with immobilized enzymes

Summary Citrate lyase and oxaloacetate decarboxylase can be rapidly and simply immobilized in polyacrylamide gel to provide a selective and sensitive reactor. Conversion ratio of citric acid to pyruvic acid comes up to 90% under the optimal conditions. Generated pyruvic acid can be determined by differential pulse polarography. The bioreactor can be used for thirty determinations over several weeks. Samples of sports drinks and wine were successfully tested without pretreatment; the relative standard deviation with 1.0×10^-5 mol l^-1 citric acid in polarographic solutions was 1.17% and the detection limit was 6.6×10^-7 mol l^-1 (=2).     

Rapid determination of total mercury in treated waste water by cold vapor atomic absorption spectrometry in alkaline medium with sodium hypochlorite solution

Addition of a sodium hypochlorite solution (9.2% (w/v)) was effective to reduce a sulfide interference in determination of organic mercury, including methylmercury and phenylmercury, as well as a previously reported determination of inorganic mercury by cold vapor atomic absorption spectrometry (CVAAS) in an alkaline medium. Total mercury ranging from 0.17 to 33 μg L⁻¹ in 15 mL of sample solutions containing up to 200 mg L⁻¹ of sulfide can be determined without any serious interference by sulfide when 1 mL of the sodium hypochlorite solution was added after dilution of the sample solution to 25 mL. The proposed method was simple and rapid because no digestion processes were required for the determination of total mercury; the time required for the determination was only about 5 min. The proposed method was applicable to the analysis of treated waste water.     

On birth and death processes in symmetric random environment

We prove a limit theorem for a process in a random one-dimensional medium, which has been considered before as a model for hopping conduction in a disordered medium. To the edge between the two integersj and (j+ 1) a rate _j > 0 is attached. These _j :j integral are taken as independent, identically distributed random variables, and represent the medium. For given values _j, X(t) is a Markov chain in continuous time which jumps fromj to (j + 1) and from (j + 1) toj at the same rate _j. We show that in many cases there exists normalizing constants y(t) (which tend to oo witht) such that the distribution of X(t)/(t), or more generally of the whole processX(st)/(t) _S0, converges to a limit as t . The limit process is continuous and self-similar.     

External chiral ligand-mediated enantioselective Peterson reaction of alpha-trimethylsilanylacetate with substituted cyclohexanones

[reaction: see text] The asymmetric Peterson reaction of an alpha-trimethylsilanylacetate with 4-substituted and 3,5-disubstituted cyclohexanones was mediated by an external chiral tridentate ligand to give the corresponding olefins with an axial chirality in high yields and enantioselectivities of up to 85%.     

Novel transformation of arenediazonium salts to acid anhydrides under palladium catalysis

Palladium catalyzed reaction of arenediazonium salts, carbon monoxide and sodium carboxylates gave mixed anhydrides, which in turn could be converted to aromatic acid anhydrides in good yields.     

Asymmetric total synthesis of natural (-)-and unnatural (+)-steganacin : Determination of the absolute configuration of natural antitumor steganacin

A virtually complete asymmetric control in the synthesis of 2,3-disubstituted butan-4-olide (10) was demonstrated by employing the butenolide (12) as the chiral acceptor for the conjugate 1,4-addition. Highly efficient asymmetric total synthesis of natural (-)- and unnatural (+)-steganacin was accomplished. The absolute stereostructure of natural antitumor steganain was determined to be 1.     

Monomer-isomerization polymerization. XIX. Monomer-isomerization copolymerizations of methylbutenes and 2-butene with Ziegler-Natta catalyst

The copolymerization of 3-methyl-1-butene (3M1B), 2-methyl-2-butene (2M2B), or 2-methyl-1-butene (2M1B) with trans-2-butene (2B) was attempted in the presence of a Ziegler-Natta catalyst. It was found the 3M1B underwent monomer-isomerization copolymerization with 2B to give a copolymer consisting of both 3M1B and 1-butene (1B) units, with an infrared (IR) spectrum in good agreement with that obtained from the copolymerization of 3M1B with 1B under similar conditions. When the apparent copolymerization parameters obtained by a TiCl₃–(C₂H₅)₃Al catalyst were compared, the apparent reactivity of 3M1B observed in the 3M1B-2B system was much higher than that in the 3M1B-1B system. However, 2M2B and 2M1B did not undergo monomer-isomerization copolymerization with 2B, and only the homopolymer of 1B was obtained under similar conditions.