Synthesis of Simple Multivalent β-D-GalNAc-(1→4)-β-D-Gal Oligomers as Probes for Investigating the Interactions of P. Aeruginosa Pili with Multivalent Receptors

ABSTRACT

Five multivalent β-D-GalNAc-(1→4)-β-D-Gal oligomers were selected and synthesized as probes for investigating the adhesin-receptor interactions of P. aeruginosa pili with multivalent receptors. They were synthesized by the amide coupling reactions of 8-(N-2-aminoethyl)carboxamidooctyl 4-O-(2-acetamido-2-deoxy-β-D-galactopyranosyl)-β-D-galactopyranoside (7) with EDTA dianhydride, EDTA, Kemp's triacid and adipic acid with EDC, DIC and DCC combined with HOBt as coupling reagents and by the reaction of per-O-acetylated 7 with 1,3,5-benzenetricarbonyl trichloride followed by de-O-acetylation. These resulting multivalent compounds contain flexible C₉ spacer arms as linkers attached to either flexible hydrophilic moieties or rigid hydrophobic cores.     

On-line dialysis and weak cation-exchange enrichment of dialysate. Automated high-performance liquid chromatography of pholcodine in human plasma and whole blood.

An automated method for the determination of pholcodine in plasma and whole blood is described. The technique combines dialysis and trace enrichment prior to high-performance liquid chromatography. Dialysis, trace enrichment on a weak cation-exchange column, separation on a cyano column and fluorescence detection was shown to be an extremely selective and sensitive method. The method has been used successfully in the analysis of real samples after administration of pholcodine. The automated method can be used, after minor modification, to determine other basic drugs in whole blood and plasma.     

All-fiber mode-locked fiber laser

An environmentally stable mode-locked fiber laser based on nonlinear polarization rotation is experimentally demonstrated. The laser is based on a novel laser configuration that has negligible low-power steady-state reflectivity from one side and, consequently, no CW gain. The laser is self starting and the configuration is implementable as an all-fiber laser with standard polarization-maintaining fiber-pigtailed components. A pulse duration of 5.6 ps is obtained at a repetition rate of 5.96 MHz and at an average power of 8 mW. As an application of the proposed laser configuration, 213 mW of supercontinuum (600-1750 nm) was demonstrated from a fiber laser system with no sections of free-space optics.     

Rheological characterization of coatings with regard to application and film formation

Summary The rheological properties and their functional dependencies, involved in the flow behavior of coatings during application and drying, are discussed. From the available rheometrical techniques a characterization of coatings is proposed, which reflects the most important rheological parameters with respect to the application process. This characterization includes measurement of (i) the change of viscosity during the drying period, (ii) the viscosity of the coating, ready for application, in the shear range from below 1 s^–1 to more than 10000 s^–1, (iii) the thixotropic recovery of viscosity at a shear rate below 1 s^–1 following shearing at a shear rate, where all structures are broken, or being at least 3 decades higher than the measuring rate, (iv) the stress relaxation from a low shear rate where relaxation times are largest or from a realistically high shear rate, and (v) the change in the composition of the material during drying in terms of evaporation.This characterization is found to be closely related to many of the different flow problems occurring in the application process. It may be extended more fully to elucidate specific problems, since the present characterization has been limited in order to make it a useful tool in routine work. For the same reason versatile rotational viscometers, normally used in coatings laboratories, are the most advanced instruments required for the characterization. This characterization, furthermore, is consistent with theoretical approaches to rheology, thereby giving access to an extension of the validity of the measurements on theoretical grounds and to use of extensive knowledge of how well-defined materials behave and interact in the design of coatings with a certain flow behavior. The framework of the characterization is found to be crucial in relating application process and rheology, whereas the specific measurements can be made in various ways.

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Zusammenfassung Die rheologischen Eigenschaften und ihre funktionellen Abhängigkeiten, welche das Fließverhalten von Anstrichstoffen während deren Applikation und Trocknung beeinflussen, werden besprochen. Mit Hilfe von gebräuchlichen rheometrischen Verfahren wird eine Charakterisierung von Anstrichstoffen vorgeschlagen, welche die wichtigsten rheologischen Parameter in Verbindung mit dem Applikationsprozeß berücksichtigt. Diese Charakterisierung umfaßt folgende Messungen: 1. Die scheinbare Viskosität während der Trocknung, 2. die Viskosität des Anstrichstoffes unmittelbar vor dessen Applikation, im Bereich von Schergeschwindigkeiten von unter 1 s^–1 bis über 10000 s^–1, 3. die thixotrope Rückbildung der Viskosität bei einer Schergeschwindigkeit unter 1 s^–1, gemessen nach Beendigung einer Scherbeanspruchung mit einer Geschwindigkeit, welche die gesamte Struktur aufzubrechen imstande war oder mindestens 3 Zehnerpotenzen höher liegt als die Meßgeschwindigkeit, 4. die Spannungsrelaxation, ausgehend von einer niedrigen Schergeschwindigkeit, wo die Relaxationszeiten am größten sind, oder von einer realistisch hohen Schergeschwindigkeit, und 5. die Veränderung des Materials während seiner Trocknung infolge Verdampfung seiner flüchtigen Anteile.Diese Charakterisierung wurde zu vielen verschiedenen Fließproblemen, wie sie während des Applikationsprozesses vorkommen, in enger Beziehung stehend gefunden. Sie könnte erweitert werden, um noch speziellere Probleme deuten zu können, doch ist die Charakterisierung als nützliches Hilfsmittel für Routinearbeiten begrenzt. Aus dem gleichen Grunde wurden für die Charakterisierung keine Instrumente vorgeschlagen, die komplizierter als Rotationsviskosimeter sind.Die vorliegende Charakterisierung ist in Übereinstimmung mit den theoretischen Grundlagen der Rheologie, so daß die Meßergebnisse auf theoretischer Basis verallgemeinert werden können. Für die Formulierung von Anstrichstoffen mit gemessenem Fließverhalten endlich können die Kenntnisse über Verhalten und Wechselwirkung theoretisch definierter Stoffe mit Nutzen angewandt werden.Der oben gegebene Charakterisierungsrahmen erwies sich als entscheidend für die Anwendbarkeit der Rheologie auf den Applikationsprozeß, die spezifischen Messungen hingegen können auf verschiedene Weise ausgeführt werden.

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Paper, presented at the Annual Conference of the Deutsche Rheologische Gesellschaft in Berlin, May 8–10, 1978.

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With 3 figures     

Explicit constructions and properties of generalized shift-invariant systems in $L^{2}(\mathbb {R})$

Generalized shift-invariant (GSI) systems, originally introduced by Hernández et al. and Ron and Shen, provide a common frame work for analysis of Gabor systems, wavelet systems, wave packet systems, and other types of structured function systems. In this paper we analyze three important aspects of such systems. First, in contrast to the known cases of Gabor frames and wavelet frames, we show that for a GSI system forming a frame, the Calderón sum is not necessarily bounded by the lower frame bound. We identify a technical condition implying that the Calderón sum is bounded by the lower frame bound and show that under a weak assumption the condition is equivalent with the local integrability condition introduced by Hernández et al. Second, we provide explicit and general constructions of frames and dual pairs of frames having the GSI-structure. In particular, the setup applies to wave packet systems and in contrast to the constructions in the literature, these constructions are not based on characteristic functions in the Fourier domain. Third, our results provide insight into the local integrability condition (LIC).