Adsorption of 4-nonylphenol ethoxylates onto insoluble chitosan beads bearing cyclodextrin moieties

In order to develop a treatment method for industrial wastewater, the adsorption of 4-nonylphenol ethoxylates (NPEs), non-ionic surfactants used in the industry, onto chitosan beads having cyclodextrin (CDC beads) was investigated. Three kinds of CDC beads containing different cyclodextrin (CD) moieties were prepared from poly-carboxymethylated α-, β- and γ-CDs. Among α-, β- and γ-CD cavities, β-CD was the most suitable for the adsorption of the phenol derivatives. The amount of adsorption was greater for the NPEs having shorter ethoxylates. Most of the NPE adsorbed on the β-CDC beads were successfully released by the treatment of the CDC beads with various aqueous alcohol solutions. After 20 cycles of the adsorption–desorption were completed, no significant decline in the adsorption amount was observed. Continuous adsorption tests were carried out using the CDC beads filled in a glass column. At the appropriate flow rate, the NPE can be adsorbed with a reasonable saturation amount.     

Syntheses of 6N(N′-formyl-D-phenylalanyl)-deoxyamino-β-cyclodextrin and 6N(N′-formyl-L-phenylalanyl)deoxyamino-β-cyclodextrin and their inclusion behavior

6N(N-formyl-D-phenylalanyl)-deoxyamino--cyclodextrin and 6N(N-formyl-L-phenylal-anyl)-deoxyamino--cyclodextrin (I andII) were prepared. These new hosts formed intramolecular host-guest complexes and included naphthyl derivatives preferentially with a stoichiometry of 1:1. The inclusion behavior was different between I and II because the cavity shape formed with the CD cavity and the phenylalanine moiety of I was different from that of II.     

Biotransformation of pinoresinol diglucoside to mammalian lignans by human intestinal microflora,and isolation of Enterococcus faecalis strain PDG-1 responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol

By anaerobic incubation of pinoresinol diglucoside (1) from the bark of Eucommia ulmoides with a fecal suspension of humans, eleven metabolites were formed, and their structures were identified as (+)-pinoresinol (2), (+)-lariciresinol (3), 3'-demethyl-(+)-lariciresinol (4), (-)-secoisolariciresinol (5), (-)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (6), 2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butane-1, 4-diol (7), 3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butane-1, 4-diol (8), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butane-1, 4-diol (9), (-)-enterodiol (10), (-)-(2R, 3R)-3-(3", 4"-dihydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (11), (-)-(2R, 3R)-2-(3', 4'-dihydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (12), (-)-(2R, 3R)-3-(3"-hydroxybenzyl)-2-(4'-hydroxy-3'-methoxybenzyl)butyrolactone (13), 2-(3', 4'-dihydroxybenzyl)-3-(3"-hydroxybenzyl)butyrolactone (14), 2-(3'-hydroxybenzyl)-3-(3", 4"-dihydroxybenzyl)butyrolactone (15) and (-)-(2R, 3R)-enterolactone (16) by various spectroscopic means, including two dimensional (2D)-NMR, mass spectrometry and circular dichroism. A possible metabolic pathway was proposed on the basis of their structures and time course experiments monitored by thin-layer chromatography. Furthermore, a bacterial strain responsible for the transformation of (+)-pinoresinol to (+)-lariciresinol was isolated from a human fecal suspension and identified as Enterococcus faecalis strain PDG-1.     

Adsorption and Recovery of Ionic Surfactants by β-Cyclodextrin Polymer

The adsorption and recovery of ionic surfactants, such as dodecylbenzenesulfonic acid (DBS) and benzalkonium chloride (BKC), from an aqueous solution were studied using the β-cyclodextrin polymer (β-CDP). BKC always demonstrated a higher adsorption efficiency than DBS in batch tests, isotherms, and column tests. The adsorption characteristics of the surfactants seemed to be caused by inclusion into β-CD, and they were easily determined using the Langmuir adsorption isotherm. Furthermore, the surfactants adsorbed by β-CDP were easily released by shaking it with a mixture of water and methanol. Recovery efficiency was dependent on the mixture ratio of the solvent, and regenerated β-CDP was reusable as an adsorbent.     

The synthesis of oligosaccharide-branched cyclodextrins and their interaction with concanavalin A

New oligosaccharide-branched -cyclodextrins having a various oligosaccharides in a primary hydroxyl group of -cyclodextrin(CD) were synthesized and examined for the interaction with the immobilized concanavalin A(ConA) compared with 6-O-glucosyl and maltosyl CD. Oligosaccharides were converted to lactones at the reducing end, which was connected with 6-monoamino--CD forming an amide bond. For the analysis of the interaction between ConA immobilized on an aminosilane-hydrogel surface and various oligosaccharide CDs, a biosensor of the FISONS IAsys apparatus based on a resonant mirror detector (RMD) was used. As a result, it interacted with immobilized ConA and both maltosyl--CD(3) and maltosyl--CD(6), and glucosylglucono-amide--CD(7) with the association constants, K_a of 134, 833 and 8730 M^–1, respectively.     

Synthesis of one-dimensional microporous todorokite and its catalytic activity in CO oxidation

Synthesis of an octahedral molecular sieve composed of Mn, Mg and O, known as todorokite, was studied in detail. The synthesis procedure is composed of three steps; layered birnessite synthesis, ion-exchange to buserite and final hydrothermal treatment of buserite. To obtain todorokites of different morphological properties, the aging time in the birnessite synthesis was varied. The effects of the aging time on properties of todorokites were studied by XRD, FE-SEM, TG-DTA, N₂ adsorption-desorption, FT-IR and CO-TPD. In addition, catalytic activities of various todorokites for CO oxidation were investigated and the correlation between properties and activities was discussed.     

Development and optimization of a lab-on-a-chip device for the measurement of trace nitrogen dioxide gas in the atmosphere

We propose the use of lab-on-a-chip technology for measuring gaseous chemical pollutants, and describe the development of a microchip for the detection of nitrogen dioxide (NO2) in air. A microchip fabricated from quartz glass has been developed for handling the following three functions, gas absorption, chemical reaction and fluorescence detection. Channels constructed in the microchip were covered with porous glass plates, allowing nitrogen dioxide to penetrate into the triethanolamine (TEA) flowing within the microchannel beneath. The nitrogen dioxide was then mixed with TEA and reacted with a suitable fluorescence reagent in the chemical reaction chamber in the microchip. The reacted solution was then allowed to flow into the fluorescence detection area to be excited by an ultraviolet light-emitting diode (UV-LED), and the fluorescence was detected using a photomultiplier tube (PMT). The reaction time, reagent concentration, pH, flow rate and other measurement conditions were optimised for analysis of nitrogen dioxide in air. Preliminary studies with standardized test solutions revealed quantitative measurements of nitrite ion (NO2-), which corresponded to atmospheric nitrogen dioxide in the range of 10-80 ppbv.     

Surface hydrogen detection by low energy He ion scattering spectroscopy

Hydrogen adsorbed on a Si(100) surface can be detected by angle-resolved LEIS (low-energy ion scattering spectroscopy) which uses a ⁴He⁺ ion beam with incident energies around 1 keV. The scattering peaks from the surface hydrogen are restricted to narrow scattering angles from 0° to 15°, which is in agreement with those expected by the binary elastic collision model.