Simultaneous Determination of Imidazole Amino Acids, Aromatic Amino Acids, and Creatinine by Dual-Mode Gradient HPLC Using a Low-Capacity Sulfo-Functionalized Poly(Ethylstyrene-Divinylbenzene) Resin Column

This paper presents a low-capacity cation-exchange chromatography method for the analysis of UV-absorbing dipeptides and amino acids. A newly marketed low-capacity cation-exchange column packed with sulfo-functionalized highly cross-linked macroreticular poly(ethylstyrene-divinylbenzene) copolymer was used for the simultaneous determination of imidazole amino acids, aromatic amino acids, and creatinine in urine samples. A dual-mode binary gradient chromatography method was established using two solvents, A: 15 mM H₃PO₄/5 mM ethylenediamine and B: 15 mM H₃PO₄/5 mM ethylenediamine/40 (v/v) % CH₃CN at 40 °C, with an optimized time program for changing the delivery ratio of A/B and the flow rate. Good chromatograms were obtained within an acceptable cycle time of 25 min. The quantification data were satisfactory for all analytes, showing the relative standard deviations (RSD) of retention times between 0.08 and 1.68 %; RSDs of area intensities between 0.23 and 2.60 %; and linear regression lines with r ² more than 0.9994. The method could determine the creatinine ratios of the diagnostic markers on the single chromatographic run, which enabled to discriminate disease from health. For example, the creatinine ratios for phenylketonuria were significantly higher than those for controls. The method can provide highly cost-efficient information or useful knowledge for clinical and pharmaceutical studies.     

Enzyme sensor for L-lactate with a chitosan-mercury film electrode

Summary An amperometric enzyme sensor composed of a mercury film electrode and an enzyme-immobilized chitosan membrane is developed. This biosensor is based on both a mercury film electrode detecting the consumption of dissolved dioxygen following enzymatic reaction, and a chitosan membrane. The latter provides an excellent permselectivity and excludes electroactive interferents. The detection range of this biosensor was 1.0×10^–5–3.0×10^–4 mol/l and the relative standard deviation, R.S.D. at 5.0×10^–5 mol/l was 1.4% (n=3). This biosensor was applied to the direct determination of L-lactate in human serum without pretreatment.     

Differential pulse-polarographic determination of organotin compounds coated on fishing nets

Summary The pulse-polarographic behaviour of tributyltin chloride (TBTC) and dibutyltin dichloride (DBTC) in ethanol-water mixtures has been studied. The effects of temperature, pH, modulation amplitude, solvent and supporting electrolyte compositions were investigated. The reduction processes are complicated and pH-dependent. DBTC gave one reversible reduction wave and TBTC showed a quasi-reversible one and also several irreversible waves. Both the organotin compounds in the concentration of 10^–7 mol/l were determined by differential pulse polarography. The method was successfully applied to the analysis of commercially available fishing nets. Detection limits were 2.2×10^–7 and 6.2×10^–8 mol/l for TBTC and DBTC, respectively.

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Differential-puls-polarographische Bestimmung von Organozinnverbindungen auf Fischernetzen

Zusammenfassung Das puls-polarographische Verhalten von Tributylzinnchlorid (TBTC) und Dibutylzinndichlorid (DBTC) in Ethanol-Wasser-Gemischen wurde untersucht und die Wirkung von Temperatur, pH, Modulationsamplitude sowie Zusammensetzung des Lösungsmittels und Leitelektrolyts geprüft. Die Reduktionsprozesse waren kompliziert und abhÄngig vom pH. DBTC ergab eine reversible Reduktionswelle, TBTC eine quasireversible Welle, sowie daneben einige irreversible Wellen. Beide Organozinnverbindungen konnten in einer Konzentration von 10^–7 mol/l durch Differential-Puls-Polarographie bestimmt werden. Die Methode wurde erfolgreich auf die Analyse von handelsüblichen Fischernetzen angewandt. Die Nachweisgrenzen lagen bei 2,2·10^–7 (TBTC) bzw. 6,2 · 10^–8 mol/l (DBTC).

This work was supported in part by a Grant-in-Aid for Scientific Research No. 554164 from the Ministry of Education. The authors wish to thank Mr. Y. Komatsu, Clean Kagaku Co., Tokyo, who offered the fishing net samples.     

Conditionally Monotone Independence II: Multiplicative Convolutions and Infinite Divisibility

We study the multiplicative convolution for c-monotone independence. This convolution unifies the monotone, Boolean and orthogonal multiplicative convolutions. We characterize convolution semigroups for the c-monotone multiplicative convolution on the unit circle. We also prove that an infinitely divisible distribution can always be embedded in a convolution semigroup. We furthermore discuss the (non)-uniqueness of such embeddings including the monotone case. Finally connections to the multiplicative Boolean convolution are discussed.     

Unification of Laughlin and Moore-Read states in SUSY quantum Hall effect

Based on the recently proposed SUSY quantum Hall effect, we show that Laughlin and Moore-Read states are related by a hidden SUSY transformation. Regarding the SUSY Laughlin wavefunction as a master wavefunction, Laughlin and Moore-Read states appear as two extreme limits of component wavefunctions. Realizations of topological excitations on Laughlin and Moore-Read states are also discussed in the SUSY formalism. We develop a stereographically projected formulation of the SUSY quantum Hall effect. With appropriate interpretation of Grassmann odd coordinates, we illustrate striking analogies between SUSY quantum Hall effect and superfluidity.     

Pattern transition of temperature distribution at Czochralski silicon melt surface

The melt surface temperature in Czochralski silicon growth was studied by CCD camera observation. The thermal radiation energy from the melt surface was converted into temperature by the blackbody calibration method and was recorded with a VCR as two-dimensional color images. The experimental results without a crystal revealed that the temperature distribution at the melt surface can change in four patterns depending on the crucible rotation rate: axisymmetric spoke pattern at low rotation rates, n-folded and island patterns at medium rotation rates, and cellular patterns at high rotation rates. To predict the fluid motion from the experimental observations, three-dimensional time-dependent numerical simulations of the silicon melt flow were executed. As a result, a qualitative transition model for the temperature distribution and the Czochralski silicon melt flow was derived.     

Free Subordination and Belinschi–Nica Semigroup

We realize the Belinschi–Nica semigroup of homomorphisms as a free multiplicative subordination. This realization allows to define more general semigroups of homomorphisms with respect to free multiplicative convolution. For these semigroups we show that a differential equation holds, generalizing the complex Burgers equation. We give examples of free multiplicative subordination and find a relation to the Markov–Krein transform, Boolean stable laws and monotone stable laws. A similar idea works for additive subordination, and in particular we study the free additive subordination associated to the Cauchy distribution and show that it is a homomorphism with respect to monotone, Boolean and free additive convolutions.