Application of a microbial sensor to the quality control of meat freshness

Isosorbide dinitrate (ISDN) is reduced voltammetrically at gold working electrode surface in aqueous sodium sulfite solution and produces a voltammogram with its peak current proportional to the concentration of ISDN in the range of 1.3-2340 mug ml(-1). Sodium sulfite is used as supporting electrolyte and oxygen removing agent and, therefore, no nitrogen gas purging for elimination of soluble oxygen in, the sample solution is required. The limit of detection (LOD) of the method is 0.0838 mug ml(-1) and the relative standard deviation (R.S.D.) of 24 replicate determination of 52 mug ml(-1) of ISDN is 3.60%. The method is used for quantitative analysis of ISDN in arterial plasma, synthetic serum and pharmaceutical dosage form. The results are compared with those obtained from GC determination method. The method is sensitive and requires little sample preparation in a wide concentration range.     

Microcolumn test and model analysis of activated carbon adsorption of dissolved organic matter after precoagulation: effects of pH and pore size distribution

Microcolumn adsorption experiments were conducted to generate breakthrough profiles of dissolved organic matter (DOM) remaining after coagulation treatment of a naturally colored surface water for three coal-based activated carbons (ACs) and four water pH levels. A plug-flow homogeneous surface diffusion model was applied to determine the intraparticle surface diffusivities of the DOM at different AC-pH combinations. It was found that, for all three ACs, the removal of DOM increased as pH decreased and the increasing extent changed with the ACs used. The pH dependency of the column performance seemed to be attributed more apparently to pH's capability in changing the zeta potential of AC particles. In addition, at all pH levels, the column performance varied markedly with the ACs used. Correlation analyses of the accumulated amounts of DOM onto all three ACs with corresponding pore volumes in several divided pore size regions clearly indicated that pores with sizes 30-100 A were more effective in adsorbing organic macromolecules. Furthermore, based on model simulations, the sensitivity of bed performance to equilibrium and kinetic parameters was quantified by conducting variance analyses with a four-way classification method.     

Biomimetic entry to acyclic terpene synthesis a novel rearrangement of allyl ether catalyzed by organoaluminium reagents

The intramolecular prenyltransfer reaction is accomplished by the rearrangement of allyl ethers with (2,6-di-$\text{tert}$-butyl-4-methylphenoxy)methylaluminum trifluoromethanesulfonate. The present method provides a simple and highly efficient synthesis of lavandulol.     

A new synthetic method for an indolizidine skeleton by C-N bond formation via a pi-allylpalladium complex

Pd(0)-catalyzed intramolecular cyclic reaction via a pi-allylpalladium complex provided an indolizidine skeleton in satisfactory high and reproducible yields by using allylic compound having an acetoxyl group as a leaving group. These results must be available for syntheses of various functional indolizidine alkaloids.     

Rapid fermentation of beer using an immobilized yeast multistage bioreactor system

A multistage bioreactor system for rapid beer fermentation was developed. The main fermentation process, which conventionally requires 7 d, could be shortened to 2 d by this system. The concentration of esters and higher alcohols are major factors in brewery fermentation, their production being closely related to the yeast growth phase. Yeast metabolism was successfully subdivided into a growth and a restricted phase through a combination of a continuous stirredtank reactor (CSTR) and an immobilized yeast packed-bed reactor (PBR). Production of higher alcohols was high in the CSTR because of its association with the level of biosynthetic activityde novo. A small amount was also produced in the PBR, however, possibly a result of an overflow in carbohydrate metabolism. Ester formation mainly occurred in the PBR, a linear increase in the level of ester being observed with flow through the PBR. The reactor system control strategy was to maximize the level of both higher alcohol and ester formation. The CSTR/PBR control range, based on extract consumption, was varied between 1:1 and 1:2. A ratio of 1:1 tended to create a flat beer, whereas a ratio 1:2 gave a beer of richer quality. Amino acid uptake by the yeast directly contributed to a reduction in the wort pH, whereas no relation could be observed between the level of organic acid production and pH.     

Determination of Stability Constants for Alkanol/α-Cyclodextrin Inclusion Complexes using the Surface Tension Method

The stability constants for the inclusion of alkanols with-cyclodextrin (-CD) in aqueous solutionhave been determined using the surface tension method. Dataanalyses assuming 1 : 1 stoichiometry were appliedto estimate the stability constants of thesecomplexes. The stability constants obtained using this methodwere in reasonable agreement with the corresponding values inthe literature. Chemically modified -CDs could not beused in this method because those CDs themselves have surfaceactivity. In addition, the relation between the stability constantsand the carbon number of alkanols is discussed.     

Selective preconcentration of rare earth elements by substoichiometric precipitation of calcium oxalate and its application to the neutron activation analysis of biological material

A preconcentration method for trace amounts of rare earth elements (REs) based on the substoichiometric precipitation of calcium oxalate was developed. RE(III) was quantitatively coprecipitated with calcium oxalate which had been precipitated from the calcium of a macrocomponent in a biological sample by addition of a substoichiometric amount of oxalate. In this way high selectivity for RE(III) from other elements was achieved. The method was applied to the neutron activation analysis of a biological sample (NBS SRM 1572 Citrus Leaves), and Sc, La, Ce, Pf, Nd, Sm, Eu, Th, Dy, Ho, Yb and Lu were determined with a relative standard deviation of less than 5%.     

Synthesis of carboxamides by LDA-catalyzed Haller-Bauer and Cannizzaro reactions

[reaction: see text] The first direct synthesis of N-alkylcarboxamides and N,N-dialkylcarboxamides by Haller-Bauer (HB) and Cannizzaro-type reactions has been realized. Lithium N,N-diisopropylamide (LDA) catalyst was successfully used in not only the HB reaction of benzylic ketones with lithium N-alkylamides to give the corresponding carboxamides and hydrocarbons but also in the Cannizzaro-type reaction of aldehydes with lithium N-alkylamides or lithium N,N-dialkylamides to give the corresponding carboxamides and alcohols.     

Imaging of nitric oxide generation in the rat brain

Nitric oxide radicals produced in the rat brain subjected to ischemia-hypoxia were trapped by the systemically administered diethyldithiocarbamate and iron. The right hemisphere of the brain was then removed and frozen with liquid nitrogen. Three-dimensional spatial distribution of the nitric oxide radicals in this hemisphere was performed using electron paramagnetic resonance imaging techniques. The results suggest that nitric oxide radicals were produced and trapped in the areas which are known to have high nitric oxide synthase activity, such as piriform cortex, hippocampus, hypothalamus, amygdala, and substantia nigra. In this model, which did not interrupt the posterior circulation, the production and trapping of nitric oxide in the cerebellum was relatively weak.     

On-line microdialysis assay of l-lactate and pyruvate in vitro and in vivo by a flow-injection system with a dual enzyme electrode

A flow-injection biosensor system with an on-line microdialysis sampling is proposed for the simultaneous assay of l-lactate and pyruvate in serum and rat brain. The dialysate collected in the sample loop by perfusing Ringer’s solution through the microdialysis probe is automatically injected into the flow-injection line with a dual enzyme electrode arranged in parallel for the flow direction. The dual enzyme electrode is constructed by hybridizing a poly(1,2-diaminobenzene) film to two sensing parts, which respond selectively to l-lactate and pyruvate, respectively, without any cross-reactivity. Both the sensing parts respond linearly to the concentrations of both analytes between 0.01 and 5 mM, without any interference from oxidizable species and low-molecular weight proteins present in the dialysate. The proposed flow-injection analysis (FIA) method can be successfully applied to the simultaneous in vitro and in vivo assays of both analytes in serum and rat brain, respectively. The system can be automatically processed at an analytical speed of 19 dialysates h⁻¹ over a period of 5 h.