Naoyoshi Egashira

Attomole detection of hemagglutinin molecule of influenza virus by combining an electrochemiluminescence sensor with an immunoliposome that encapsulates a Ru complex.

An immunoliposome (80 nm in diameter) encapsulating a Ru complex with two aminobutyl moieties was prepared to detect the presence of hemagglutinin molecules, which play an important role in influenza virus infection. The highly sensitive detection was accomplished by electrochemiluminescence (ECL) from the Ru complex adsorbed onto Au electrodes after competitive immunoreactions. This method clarified that the adsorption of the Ru complex onto the electrode was an important factor in obtaining high sensitivity. Optimization of the analytical conditions enabled determination of the hemagglutinin molecules of the influenza virus in the concentration range of 3 x 10(-14) (6 x 10(-19) mol/50 microL sample) to 2 x 10(-12) g/mL. The sensitivity was far superior to that obtained by conventional ELISA as well as to that obtained by biosensors and reported thus far.

Electrochemiluminescence oxalic acid sensor having a platinum electrode coated with chitosan modified with a ruthenium (II) complex

Abstract An electrochemiluminescence (ECL) sensor having a Pt electrode coated with a tris(2,2′-bipyridine)ruthenium (II)(Ru(II) complex)-modified chitosan responded to oxalic acid more strongly than to several other substrates. The ECL response intensity to oxalic acid was reproducible within 5% (RSD) on 10 repeated runs. A calibration curve for oxalic acid gave a straight line in the concentration range of 0.1 to 10 mM (correlation coefficient, 0.997) and the detection limit (S/N=3) was estimated to be 3×10 −5 M. Interestingly, the response to trimethylamine was 39 times as weak as that obtained with a bare Pt electrode in an aqueous solution where the Ru(II) complex coexisted. The appearance of the high selectivity can be explained partly on the basis of the electrostatic repulsion of the chitosan membrane having a positive charge with trimethylamine, as being supported by cyclic voltammetry.

Mechanochemical degradation of chlorinated contaminants in fly ash with a calcium-based degradation reagent.

This report presents our results in a low-temperature mechanochemical hydrodechlorination process applied to fly ash coming from a municipal waste incinerator in order to efficiently remove all traces of PCDDs, PCDFs and PCBs. We found that the most suitable degradation agent is a mixture of metallic calcium and calcium oxide. A sample of fly ash presenting a TEQ of 5200 pg g(-1) was completely detoxified (no traces of PCDDs, PCDFs and PCBs detected) after ball-milling at 400 rpm over night.

Highly effective degradation of polychlorinated biphenyls in soil mediated by a Ca/Rh bicatalytic system.

Treatment of PCBs in soil using metallic calcium and alcohol ultimately reduced 1300 x 10(-3)mgkg(-1) PCB concentration to 1.8 x 10(-3)mg kg(-1). Moreover, using the metallic calcium catalyst method to promote the effective use of hydrogen gas in the presence of a specific reducing catalyst such as Rh/C, the decomposition efficiency of PCBs was notably increased despite mild reaction conditions. The total PCB concentration of treated soils decreased from 1300 x 10(-3)mg kg(-1) to 0.62 x 10(-3)mg kg(-1) (decomp. avg.=99.95%). Treatment of soils with metallic calcium and a Rh/C catalyst in alcohol under mild conditions such as 0.15-0.26 MPa at room temperature is extremely effective for degradation of existing PCBs.

Novel Mild Hydrodechlorination of PCDDs, PCDFs, and co-PCBs inside Fly Ash Using a Calcium-Promoted Rhodium Carbon Catalyst in Methanol

Environmental Context. The generic term ‘dioxins’, the family of which includes polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls (co-PCBs), is used to describe highly toxic and mutagenic compounds. Many methods that involve high-temperature or high-pressure dry hydrogen conditions to ensure adequate decomposition for persistent chlorinated aromatic pollutants present disadvantages for repeated synthesis or recovery of vaporized dioxins and co-PCBs. We discovered that highly efficient degradation of dioxins in fly ash is accomplished in 24 h using metallic calcium and Rh/C in alcohol in a sealed tube at 25°C at 0.15 MPa. Abstract. Effective hydrodechlorination of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like compounds such as coplanar polychlorinated biphenyls in fly ash was achieved in 24 h using a simple stirring operation in a sealed tube with metallic calcium and Rh/C catalyst in an alcohol solution at room temperature with 0.15 MPa of increasing internal pressure. The initial 7806 pg dioxin toxic equivalent (TEQ) (g of ash)–1 of dioxins in fly ash, which had adsorbed inside the solid phase, was finally degraded to 23.6 pg of TEQ (g of ash)–1, according to estimation using gas chromatography–mass spectrometry analysis.

Quadruple Decker [3.3][3.3][3.3]Orthocyclophane Acetal—An Orthocyclophane Ladder

Through clever bridging of orthocyclophanes (in this case by acetalization), molecules such as 1 can be formed with four benzene rings in a stacked face-to-face arrangement. UV/Vis spectroscopic and electrochemical properties of 1 are governed by π-π through-space interactions within the molecule.

Electroreductive dimerization of acetyl compounds in dimethylformamide

Abstract Seven acetyl compounds were cathodically electrolyzed in dimethylformamide containing TBAI and LiI to give corresponding hydrodimers in good yields respectively. On the basis of the rate constant of dimerization determined by use of digital simulation, it was found that the dimerization proceeded through anion radical (R − )/ion-pair (R − Li + ) coupling in all the cases that a linear relationship existed between the logarithm of the rate constant and electron spin density at the carbonyl carbon.

Highly meso-Diastereoselective Pinacol Coupling of Aromatic Aldehydes Mediated by Al Powder/Copper Sulfate in Water

Abstract Pinacol-type coupling reaction products presenting a high meso-diastereoselectivity (the ratio dl/meso was 4/96 up to 1/99) were obtained in fair to good yields (24–69%) using several aromatic aldehydes as starting materials and aluminium powder/copper sulfate as catalysts, in water, under reflux conditions.

Fabrication of a Trimethylamine Gas Sensor Based on Electrochemiluminescence of Ru(bpy)

The present sensor on the basis of electrochemiluminescence generated from Ru(bpy)/ anionic perfluoropolymer Nafion coated electrode responded strongly to trimethylamine gas. The response gave a straight line in the concentration ranging from 10 to 310 ppb and the lower detection limit was 3 ppb (S/N =3). The sensor was applied to seafood as practical samples and the response for a squid was almost consistent with a profile curve obtained from the K value measurement as an alternative freshness index.

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Various thioesters were obtained through an efficient phase-transfer catalysis method, by treating several thiophenols with different acyl chlorides, in a biphasic system composed of 10% aqueous NaOH and dichloromethane in the presence of tetrabutylammonium chloride. The thiolation reaction was complete in only 5 minutes, at 0°C.