Problem solving as intelligent retrieval from distributed knowledge sources

Distributed computing in intelligent systems is investigated from a different perspective. From the viewpoint that problem solving can be viewed as intelligent knowledge retrieval, the use of distributed knowledge sources in intelligent systems is proposed

DETERMINATION OF PORE SIZE DISTRIBUTION IN CAPILLARY-CHANNELED POLYMER (C-CP) FIBER STATIONARY PHASES BY INVERSE SIZE-EXCLUSION CHROMATOGRAPHY (ISEC) AND THE STUDY OF THE ROLE OF INTERSTITIAL FRACTION ON C-CP FIBERS ON PROTEIN BINDING CAPACITY

ABSTRACT High performance liquid chromatography (HPLC), first used in the 1960\u27s, is a rapidly evolving analytical technique, widely employed for identification, separation, and purification in biotechnology and pharmaceutical industries. The development of the stationary phases has played an important role in improving this technique. Each stationary phase will have its own disadvantages. Polysaccharide-based stationary phases such as cross-linked dextran cannot tolerate high pressures and linear velocities; silica stationary phases are rigid enough but slow mass transfer in the pores on the surface causes another problem; with the introduction of non-porous and small bead packing materials, the low surface area and high backpressure still handicapped people from achieving better separations. Therefore, fiber based polymer stationary phases came into view. Capillary-channeled polymer (C-CP) fibers have been investigated in the Marcus laboratory for several years as a stationary phases for ion-exchange (IEC), reversed phase (RP), and hydrophobic interaction (HIC) chromatography. When packed into a column, the unique eight-channeled shape makes them interdigitate to form parallel channels with high surface area-to-volume ratio and low backpressure. Additionally, C-CP fibers are virtually non-porous toward large molecules, which decreases the mass transfer to achieve fast protein separations. In the first study, polypropylene (PP) C-CP fibers and inverse size exclusion chromatography (iSEC) were employed to determine the pore size distribution (PSD) on the surface of the fibers. With the findings of mean pore size radius and standard deviation, the fibers\u27 geometric structure and adsorption behavior is better understood. In the second study, with the evaluation of the effects of different factors such as interstitial fraction and flow rate on the loading capacity of nylon-6 fibers, the kinetic and thermodynamic properties of the fibers have been further revealed. All results presented the potential of C-CP fibers as an innovative stationary phase for fast macromolecule separations

Weak center for a class of Λ–Ω differential systems

In this paper, we give the necessary and sufficient conditions for a class of higher degree polynomial systems to have a weak center. As corollaries, we prove the correctness of the two conjectures about the weak center problem for the Λ–Ω differential systems

On the analytic commutator for Λ–Ω differential systems

In this paper, we give the necessary and sufficient conditions for some Λ–Ω differential systems to have an analytic commutator, use these properties to judge the origin point of the Λ–Ω differential systems to be an isochronous center

Formal total synthesis of pseudopteroxale : progress toward total synthesis of hamigeran B

Title from PDF of title page (University of Missouri--Columbia, viewed on May 21, 2012).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Michael HarmataVita."July 2011"In the first chapter, a formal total synthesis of pseudopteroxazole is presented, highlightening an E-selective Horner-Emmons reaction, a Buchwald-Hartwig coupling, and a diastereoselective intramolecular Michael addition. In the second chapter, the effort toward synthesizing anti-viral natural product hamigeran B is summarized. Several routes to the core structure were shown separately, including those unexpected discoveries when pursuing those routes. Tius-Nazarov cyclization was first applied in synthesizing natural product; an efficient palladiumcatalyzed oxidative intramolecular carbocyclization was realized on an α-hydroxy enone for the first time; an interrupted Nazarov cyclization of a hydrolysis intermediate of dithiane was achieved.Includes bibliographical reference