Preparation of β-cyclodextrin sulfate-immobilized hydrophilic vinyl-polymer gel as a selective,high recovery and stable adsorbent for high-performance affinity chromatography of heparin-binding substances

Summary β-Cyclodextrin sulfate having heparin-mimicking activity was immobilized on a hydrophilic vinyl-polymer gel, TSKgel AF-Epoxy, TOYOPEARL 650M. A column packed with this material could be used for high-performance affinity chromatographic separation of heparin-binding substances such as growth factors, enzymes, coagulation factors and lipoproteins. The substances retained on the column were recovered more easily than those on a heparin-immobilized column. Furthermore, the β-Cyclodextin sulfate-immobilized gel was superior in stability to the heparin-immobilized gel when exposed to acidic and basic solutions.     

Epitaxial growth of InN on nearly lattice-matched (Mn,Zn)Fe2O4

We have grown InN films on nearly lattice-matched (Mn,Zn)Fe₂O₄ (111) substrates at low temperatures by pulsed laser deposition (PLD) and investigated their structural properties. InN films grown at substrate temperatures above 400 °C show poor crystallinity, and their in-plane epitaxial relationship is [10-10]InN//[11-2](Mn,Zn)Fe₂O₄, which means that their lattice mismatch is quite large (11%). By contrast, high quality InN films with flat surfaces can be grown at growth temperatures lower than 150 °C with the ideal in-plane epitaxial relationship of [11-20]InN//[11-2](Mn,Zn)Fe₂O₄, which produces lattice mismatches of as low as 2.0%. X-ray reflectivity measurements have revealed that the thickness of the interfacial layer between the InN and the substrates is reduced from 14 to 8.4 nm when the growth temperature is decreased from 400 °C to room temperature. This suppression of the interface reactions by reducing the growth temperature is probably responsible for the improvement in crystalline quality. These results indicate that the use of (Mn,Zn)Fe₂O₄ (111) substrates at low growth temperatures allows us to achieve nearly lattice matched epitaxial growth of InN.     

Application of a new capsule-type silica gel coated with hydrophobic polymer to preparative liquid chromatography on an industrial scale

Summary A new type of column packing material designed for preparative liquid chromatography, silicone polymer-coated silica gel modified with octadecyl group (S/S-C₁₈), was applied to chromatographic purification of a lipophilic biotechnological product. Triglycerides containing γ-linolenic acid were separated from the curde oil that consisted of triglycerides, diglycerides, free fatty acids, sterols and other polar substances, using a S/S-C₁₈ packed column (150 mm I.D. × 1000 mm). No column deterioration was observed after more than 1500 times of sample introductions.     

Nonequilibrium interface equations: An application to thermocapillary motion in binary systems

Interface equations are derived for both binary diffusive and binary fluid systems subjected to nonequilibrium conditions, starting from coarse-grained (mesoscopic) models. The equations are used to describe thermocapillary motion of a droplet in both purely diffusive and fluid cases, and the results are compared with numerical simulations. A mesoscopic chemical potential shift owing to the temperature gradient, and associated mesoscopic corrections involved in droplet motion, are elucidated.     

Evaluation of a quantitative method for trace impurities in arsenous acids by synchrotron radiation X-ray fluorescence spectrometry and inductively coupled plasma-atomic emission spectrometry.

Thirteen arsenous acid samples of known origins and refining methods were collected. Each sample was subjected to quantitative analysis of any impurity elements present using synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The trace elements selected were Sn, Sb and Bi for the reasons that they were considered not to be changed by their circumstances and that they showed high sensitivity to SR-XRF. These results obtained by both methods were compared and the correlation between these two methods was determined. The quantification of trace impurities obtained by SR-XRF using As as an internal standard showed good agreement with the results obtained by ICP-AES. The discrimination of refining method became possible by the comparison of these impurities' contents measured with non-destructive SR-XRF using several arsenous acid particles.     

Microchip electrophoresis for specific gene detection of the pathogenic bacteria V. cholerae by circle-to-circle amplification.

We have developed a new method for a fast and precise analysis of circle-to-circle amplification (C2CA) product for specific gene detection by microchip electrophoresis. In this method, we have added a new enzymatic step to the C2CA reaction, which could be carried out isothermally at 37 degrees C. Compared to the original single-stranded DNA, the double-stranded DNA that is produced by this enzymatic reaction is more reliable for analysis by microchip electrophoresis. C2CA product was detected within 55 s with high reproducibility by this method which was successfully applied to the detection of 10-ng genomic DNA of the pathogenic bacteria Vibrio. cholerae within 110 s. Purification was found to be an indispensable step for the analysis of the C2CA product of genomic DNA samples.     

Electrothermal atomization of calcium and strontium in a molybdenum micro-tube

The excitation and ionization of calcium and strontium in a molybdenum micro-tube atomizer and their use in atomic-absorption spectrometry are described. Increasing hydrogen flow led to complex calcium atomization profiles for absorption measurements, but decreasing hydrogen flow resulted in higher atomic emission. Ionization of calcium and its suppression by potassium were also observed. Strontium was measured effectively by atomic absorption because of the higher sensitivity. Increasing hydrogen flow resulted in a lower atomization temperature and higher absorption for strontium, while decreasing hydrogen flow resulted in higher atomic emission. No interference from 100-fold amounts of magnesium, calcium and sodium was found for atomization of strontium, but 100-fold amounts of aluminium shifted the peak temperature for strontium though with no variation of appearance temperature and peak absorption. A small shift in peak temperature was observed for strontium in the presence of 100-fold amounts of phosphate.     

Overlapping block diagonal dominance and existence of Liapunov functions

The main objective of this paper is to formulate a generalization of block diagonal dominance, which can be used to establish nonsingularity of matrices via overlapping diagonal blocks. A number of stability results are derived in the new setting by exploiting the well-known M-matrix properties, as well as extensions of the normalization, scaling, and alternative norm utilization. A link between generalized block diagonal dominance and vector Liapunov functions is established, which can be applied in the stability analysis of interconnected dynamic systems.     

The influence of short branches on the α, β and γ-relaxation processes of ultra-high strength polyethylene fibers

Dynamic mechanical measurements were conducted for several kinds of ultra–high-strength polyethylene fibers with different methyl branch contents. As is the case with conventional polyethylene materials, UHSPE fibers also exhibit α, β, and γ-relaxation dispersions. Each relaxation process is the function of both the tensile moduli and the branch contents of UHSPE fibers. It was also found that the γ-process of UHSPE fibers is dominated mainly by the localized molecular motion in the crystalline part, such as a dislocation mode of crystallite defects, which is very sensitive to the branching content. From the time and temperature superposition of the frequency dispersion experiments, it was found that activation energies for both the α2-process and α3-process increase proportionally to the methyl branch content, while the α1-process is not so affected by the branch content. This result shows that the incorporated branch sites in the crystalline part effectively hinder the chain-to-chain slippage; meanwhile, they have not hindered the slippage at the grain boundary so far, which also enables us to explain the creep improvement of UHSPE fibers through branch incorporation with the same mechanism. © 1994 John Wiley & Sons, Inc.     

Electrothermal atomization with a metal micro-tube in atomic absorption spectrometry

The processes of atom formation and dissipation in a molybdenum micro-tube atomizer have been studied to obtain information on the reaction involved. Vapor temperature was found to be close to atomizer surface temperature. Appearance temperatures and activation energies were obtained for Al, Co, Cu, Mn, Pb, Sb, Se, Sn and Te in argon and argon-hydrogen atmospheres. The atom formation processes are divided into two groups : the reduction of the metal oxide followed by the atomization of free metal, and thermal dissociation of the metal oxide. Hydrogen significantly changes atom formation processes for some metals compared to those in pure argon. The dissipation process of atoms from the micro-tube atomizer appears to be purely gas-phase diffusional.