Investigation of the possibility of geometrical electrophoresis

We investigate the possibility of geometrical electrophoresis, which is based on nanofabrication techniques. (GEE) utilizes geometrical effects during electrophoresis, which are generated by physical interactions between walls and a macromolecule confined in spaces smaller than the Flory radius. When a polymer is injected into a small space, confinement energy is usually required. However, the confinement energy form depends on the geometry of the space. In the case of electrophoresis, the electric field itself changes depending on the geometry. Using a nanofabricated quartz chip with a curved channel, we investigated electrophoretic behavior of high molecular weight DNA based on the curvature effect.     

Efficient synthesis of antihyperglycemic (S)-alpha-aryloxy-beta-phenylpropionic acid using a bifunctional asymmetric catalyst

Antihyperglycemic (S)-alpha-aryloxy-beta-phenylpropionic acid was prepared using catalytic asymmetric cyanosilylation as a key reaction to construct alpha-oxycarboxylic acid moiety.     

Syntheses and characterization of μ-Bis{N-(oxopropyl)-glycinamidato}-dicopper(II) and μ-Bis{n-(oxopropyl)-DL-alaninamidato}-dicopper(II)

Two new complexes, [Cu(OP-gld)]₂ and [Cu(OP-alad)]₂ (shown in Fig. 2) with a subnormal magnetic moment have been synthesized and characterized by means of analyses, magnetic susceptibility measurements, IR-, and electronic spectra, and conductivity measurement.     

Application of the vanadium(V)-xylenol orange reagent to the assay of serum glucose

The VXO reagent (mixture of V(V) and xylenol orange) provided in our earlier studies is found very useful for the colorimetric determination of traces of hydrogen peroxide. In this paper the reagent is successfully extended to the assay of glucose in serum by the combined use of glucose oxidase.The VXO reagent exhibited a characteristic absorption maximum at 582 nm, and the presence of glucose together with glucose oxidase led to a significant decrease in the absorbance of the reagent. A linear relation was found between the magnitude of the decrease and glucose concentration in the range of 5 to 400 mg/100 ml. The average recovery of glucose added in serum was 98.6% and the data were reliable with a coefficient of variation below 3.0%. A good correlation to the method by 4-aminoantipyrine-phenol was found: r = 0.970. Ascorbic acid and uric acid did not interfere with the assay.     

Redox properties of isradipine and its electrochemical detection in the HPLC determination of the compound in human serum

The electrochemical behaviour of isradipine in a mixed solution of Britton-Robinson buffer (pH 11.8):acetonitrile:methanol (6:3:1, v/v) was studied by cyclic voltammetry and spectroelectrochemistry using an optically transparent thin layer electrode of carbon cloth. The cyclic voltammogram showed several peaks whose shape and potentials depended on the pH. The peak at 330 nm, corresponding to the absorbance of the dihydropyridine ring, disappeared after electrolysis at a potential that was more positive than the oxidation peak. The oxidation peak corresponds to the oxidation of the dihydropyridine ring. Peak height at pH 11.8 was proportional to isradipine concentration. On the basis of the redox properties of isradipine, HPLC was conducted applying electrochemical detection on a polybutadiene coated alumina column using an alkaline mobile phase. The method was applied for the determination of isradipine content in human serum. A good linear relationship between isradipine concentration and peak height was found in the concentration range of 2-200 ng/mL with a correlation coefficient of 0.9924. The detection limit was 0.5 ng/mL. The within-day and day-to-day variation were examined for control human serum and percentage relative standard deviation ranged from 0.5 to 6.7. Interference from many other coadministered drugs was studied in the specified experimental conditions. Photo and heat stabilities of the compound were also studied.     

Three new steroid glycosides from the underground parts of Trillium kamtschaticum

Three new steroid glycosides named trikamsterosides C, D and E were isolated from the underground parts of Trillium kamtschaticum PALL. (Liliaceae) along with two known 18-norspirostanol glycosides trillenosides A and B. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence.     

New entry for synthesis of N-acylhydrazones, pyridazinones, and 1,3,4-oxadiazin-6-ones from alpha-amino acid esters

Versatile electrophiles N-acylhydrazones are synthesized via diazotization, reduction, and acylation of alpha-amino acid esters. Reduction of diazo esters with L-selectride or tributylphosphine affords the corresponding hydrazones in good yields. Both reducing agents give anti-hydrazones as the major product although the reactivity of each reductant is slightly different. The resulting hydrazones are acylated to give N-acylhydrazones, which are subjected to further reactions to give 1,3,4-oxadiazin-6-ones that serve as useful synthetic intermediates for the Diels-Alder reaction.     

Synthesis and cationic ring-opening polymerization of mono- and bifunctional spiro orthoesters containing ester groups and depolymerization of the obtained polymers: An approach to chemical recycling for polyesters as a model system

A spiro orthoester having an ester moiety, 2-acetoxymethyl-1,4,6-trioxaspiro[4.6]undecane (4) was synthesized, and its cationic polymerization and depolymerization of the obtained polymer (5) were carried out. The monomer 4 underwent cationic polymerization with a cationic catalyst to afford the corresponding poly(cyclic orthoester) 5. The obtained polymer 5 could be depolymerized with a cationic catalyst to regenerate the monomer 4 in an excellent yield. Further, bifunctional spiro orthoesters (6, 8, 9) having diester moieties were synthesized from terephthalic acid, succinic acid, and 1,4-cyclohexanedicarboxylic acid, and their acid-catalyzed reversible crosslinking–decrosslinking was examined. The bifunctional monomer 6 derived from terephthalic acid underwent cationic crosslinking to afford the corresponding network polymer (7), which could be also depolymerized to regenerate the original bifunctional monomer 6. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2551–2558, 1999     

Influence of Plasma Resistance and Fluctuation on Probe Characteristics in Detached Recombining Plasmas

In order to find the causes of the strong anomaly of current‐voltage characteristics of Langmuir probe observed in detached recombining plasmas in a linear divertor plasma simulator, NAGDIS‐II, we have investigated plasma resistance along a magnetic field and potential fluctuations in the detached recombining plasmas. Simple calculation on the ratio between the plasma length, at which plasma resistance and resistance of ion sheath formed around a probe tip become equal, and an electron collection length indicates that the evaluation of electron temperature T_e becomes inaccurate at T_e of less than 0.6 eV when plasma density and neutral pressure are 1.0 × 10¹⁸ m^—3 and 10 mtorr, respectively. The potential fluctuation in detached recombining plasmas was found to be so large compared to T_e/e, which can also modify the probe characteristics.     

Simultaneous Observation of NO2 Column Density and Aerosol Optical Thickness in Urban Atmosphere

Ground-based, optical monitoring of the NO₂ column density and aerosol optical thickness is described. The instrument consists of a solar radiation spectrometer and a conventional sunphotometer, both mounted on a sun-tracker and operated automatically. From daytime measurements in Chiba during the winter of 1998, variations of NO₂ and aerosol are analyzed. Because of the capability of simultaneous, real time measurement, this method is particularly suitable for air pollution studies in city areas.