Automatic analysis of serum lactate dehydrogenase isoenzymes by high-performance ion-exchange chromatography

The repetitive analysis of serum lactate dehydrogenase (LDH) isoenzymes has been performed on a weak anion exchanger (TSKgel DEAE-5PW), which was developed by introducing diethylaminoethyl groups into TSKgel G5000PW (10 microns particle diameter)--a hydrophilic polymer-based material of large pore size--for high-performance gel chromatography. By use of this anion exchanger, a high-pH (greater than 8.0) solvent could be used and the albumin peak was completely separate from the LDH isoenzyme peaks. After 10 successive analyses with an autosampler, the coefficient of variation of the LDH isoenzyme elution times was less than or equal to 0.90%, and the coefficient of variation for peak areas was less than or equal to 3.85%. After 40 successive analyses, resolution between isoenzymes was generally greater than 1.25. This column can be used for more than 300 intermittent injections of human serum.     

Effect of particle addition on sonochemical reaction

Enhancement of chemical reaction with a photocatalyst of titanium dioxide (TiO(2)) by ultrasonic irradiation is studied through the absorbance measurements for liberation of iodine from a KI aqueous solution as an index of oxidation reaction. It is well known as a synergetic effect that the addition of TiO(2) fine particles under UV has an ability to enhance the yield in chemical reaction with OH-radical from hot spot at violent collapse of cavitation bubbles with intense ultrasound. In this study, the absorbance is measured after simultaneous irradiation of ultrasound and UV with the addition of TiO(2) much less than the usual concentration by two orders of content. It is shown that, even in case of quite a little TiO(2) addition where the photocatalytic effect is less, the yield is enhanced obviously in comparison with the summation in yield of independent procedure of ultrasound without TiO(2) and UV with TiO(2). The absorbance-peak deviation to the shorter wavelength implies the generation of titanium peroxide (TiO(3)). The effect of particle addition is due to the chemically activated particle surface on the TiO(2) and probably to the increase in the cavitation bubbles that results in promoting a transfer of OH-radical and other oxidants to bulk liquid region at the collapse.     

High-pressure Raman study of Ba doped silicon clathrate

Vibrational properties of Ba doped Si clathrate are investigated at high pressures up to 20 GPa by Raman spectroscopy. Vibrations related with Ba encaged in the Si cages are observed below 100 cm(-1) by low-frequency Raman measurements of Ba8Si46 and Ba6.6Si46 clathrates. The high-pressure Raman spectra obtained for both compression and decompression processes reveal a new phase transition at 7 GPa, and the reversibility of the phase transition at 15 GPa. We investigate the mechanisms of these phase transitions, the interaction between the guest and host frame, and the volume dependence of the vibrational modes.     

Coexistence of long-range order and spin fluctuation in geometrically frustrated clinoatacamite Cu2Cl(OH)3

Muon spin rotation experiments are carried out on clinoatacamite, Cu2Cl(OH)3, which is a new geometrically frustrated system featuring a three-dimensional network of corner-sharing tetrahedral 3d Cu2+ spins. A long-range antiferromagnetic order occurs below 18.1 K with a surprisingly small entropy release of about 0.05Rln2/Cu. Below 6.5 K, the static long-range order transforms abruptly into a metastable state with nearly complete depolarization of muon spins which suggests strong fluctuation. The system then enters a state in which partial long-range order and spin fluctuation coexist down to the lowest experimentally attainable temperature of 20 mK. This work presents a novel system for studying geometric frustration.     

Effects of dissolved gas species on ultrasonic degradation of (4-chloro-2-methylphenoxy) acetic acid (MCPA) in aqueous solution

Sonochemical degradation of MCPA ((4-chloro-2-methylphenoxy) acetic acid) in dilute aqueous solutions was studied using ultrasound with a frequency of 500 kHz. The effect of gas atmosphere on MCPA degradation was investigated in nitrogen (N(2)), air (O(2)/N(2)), oxygen (O(2)), argon (Ar) and Ar/O(2) (60/40% v/v) atmospheres. For sonochemical degradation of MCPA in N(2), air (O(2)/N(2)), O(2) and Ar atmospheres, the rate enhancement of MCPA decomposition by sonolysis was found to be more effective in an O(2)-enriched atmosphere compared to Ar atmosphere. It was considered that a higher amount of oxidants was formed in a higher O(2) partial pressure, which accelerated MCPA decomposition in a radical reaction system. On the other hand, both dechlorination and total organic carbon (TOC) removal rates were higher in Ar atmosphere, compared to those in O(2)/N(2) atmosphere. It was found that, MCPA was most effectively decomposed by sonication in Ar/O(2) (60/40% v/v) atmosphere, with higher rates of decomposition, dechlorination and TOC removal.     

Study of Salt Effects on the Micelle-Monomer Exchange Process of Octyl-, Decyl-, and Dodecyltrimethylammonium Bromide in Aqueous Solutions by Means of Ultrasonic Relaxation Spectroscopy

Spreading of a tiny macroscopic droplet of a nonvolatile, completely wetting liquid over a flat solid is considered. A liquid in creeping is subjected to capillary forces and long-range molecular forces. The droplet may be surrounded with a precursor wetting film. This paper deals with the problem of determining of the microscopic parameter that influences the interface shape near the apparent line of wetting; this is regarded as the inverse problem in the hydrodynamics of wetting. If the system includes a precursor film, the microscopic parameter coincides with the maximum thickness of the film. A series of inverse equations for the microparameter is obtained, which relate it to, first, the current geometric parameters of the macroscopic drop part and, second, the spreading time. A method for determining how the microparameter depends on the wetting line speed is proposed. The theory expands the opportunity to perform macroscopic measurements and reveals additional parameters. The inverse relations may be used to experimentally study the growth of the maximum thickness of a precursor film during drop spreading. Copyright 2000 Academic Press.     

New steroid‐group‐containing borazine compounds and their 13C NMR spectra

New borazine compounds containing steroid units (cholesteryl and stigmasteryl) were prepared by the reactions of B,B′,B″‐trichloro‐N,N′,N″‐trimethylborazine with the 3‐chloro derivatives of the corresponding steroids under Grignard conditions. The products were characterized by ¹³C–¹H correlation NMR measurements to give fully assigned ¹³C NMR data. Copyright © 2001 John Wiley & Sons, Ltd.