Preparation and Characterization of 61,6n-DI-O-(α-D-Galactopyranosyl)Cyclomaltooctaoses

ABSTRACT

Four positional isomers of 6¹,6ⁿ-di-O-(D-galactopyranosyl)cyclomaltooctaoses (cG₈s, γ-cyclodextrins) (n = 2?5) were chemically synthesized using the trichloroacetimidate method. The desired compounds having two α-(1→6)-linkages were isolated from a mixture of configurational isomers by HPLC, and their structures were confirmed by ¹³C NMR spectroscopy and FAB-high resolution mass spectra (HRMS). The elution behavior of their four positional isomers on an ODS column by HPLC is discussed.     

固态汞合金电极吸附伏安法测定酪氨酸

采用白合金粉与汞混合制成汞合金糊,涂布在固体石蜡碳糊电极表面,固化后制得固态汞合金电极,并首先应用于酪氨酸的测定。在含Co2 的pH 9.2的硼砂-NaOH底液中,用线性扫描伏安法在-0.80~-1.30V范围内进行扫描,酪氨酸于-1.05 V出现灵敏的还原峰,酪氨酸的浓度与峰电流在1.0×10-7~1.0×10-5mol/L范围内呈线性关系。该法已用于复方氨基酸注射液中酪氨酸含量的测定,加标回收率达96%~102%。该电极既保留了汞电极的优点,又避免了汞电极有毒、使用不方便的缺点。     

Noncommuting (S 5, S 5)-Amalgams

ABSTRACT

Rank 2-amalgams (P ₁, P ₂, B), in which P ₁/O ₂(P ₁) ? P ₂/O ₂(P ₂) ? S ₅, are analyzed using the amalgam method. It is determined that in the noncommuting case either |O ₂(P ₁)| = |O ₂(P ₂)| ≤ 2⁶ or (P ₁, P ₂, B) has the same shape as an amalgam in Aut(G ₂(4)).     

Weighted restriction theorems for space curves

Consider a nondegenerate Cn curve γ(t) in Rn, n?2, such as the curve γ₀(t)=(t,t²,…,tn), t∈I, where I is an interval in R. We first prove a weighted Fourier restriction theorem for such curves, with a weight in a Wiener amalgam space, for the full range of exponents p, q, when I is a finite interval. Next, we obtain a generalization of this result to some related oscillatory integral operators. In particular, our results suggest that this is a quite general phenomenon which occurs, for instance, when the associated oscillatory integral operator acts on functions f with a fixed compact support. Finally, we prove an analogue, for the Fourier extension operator (i.e. the adjoint of the Fourier restriction operator), of the two-weight norm inequality of B. Muckenhoupt for the Fourier transform. Here I may be either finite or infinite. These results extend two results of J. Lakey on the plane to higher dimensions.     

Calderón-Zygmund operators on amalgam spaces and in the discrete case

We prove the boundedness of Calderón-Zygmund operators on weighted amalgam spaces for 1<p,q<∞ with Muckenhoupt weights. To do this, we show the boundedness in the discrete case, i.e. the boundedness on . We also investigate on . As an application we consider an operator related to the Navier-Stokes equation.     

Hydrodynamic Correlation Functions for Binary Mixtures

Abstract

Correlation functions of various local thermodynamic variables of binary mixtures are obtained from the linearized hydrodynamic equations following the method of Mountain and Deutch. “Non-Lorentzian” parts of the time Fourier transformed correlation functions which have not been included by these authors are obtained here and their effect on the light scattering spectrum considered. An extension of the treatment by Fox and Uhlenbeck of Landau and Lifshitz hydrodynamical fluctuation theory to binary mixtures has been accomplished and correlation functions of the "fluctuating forces" are obtained for this case.     

Comparison of Mercury Vapor Pressure of Silver Amalgam-Based Electrode Materials Using AAS

Nowadays, several amalgam-based electrodes are commonly used in electrochemistry as a less toxic alternative to mercury electrodes. Therefore, a comparison of the mercury vapor pressure of several silver amalgam-based electrode materials with the mercury vapor pressure of liquid mercury and of dental amalgam using AAS was done in this study. Method was optimized to get the highest mercury signal. Results showed that the mercury vapor pressure of amalgam-based electrode materials not containing liquid mercury is far lower than the mercury vapor pressure of liquid mercury (about two orders of signal magnitude) and comparable with mercury vapor pressure of dental amalgam.