870 resultados para Preparation and behavior of Indian teachers
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The discovery and characterization of oncofetal proteins have led to significant advances in early cancer diagnosis and therapeutic monitoring of patients undergoing cancer chemotherapy. These tumor-associated antigens are presently measured by sensitive, specific immunoassay techniques based on the detection of minute amounts of labeled antigen or antibody incorporated into immune complexes, which must be isolated from free antigen and antibody.^ Since there are several disadvantages with using radioisotopes, the most common immunolabel, one major objective was to prepare covalently coupled enzyme-antibody conjugates and evaluate their use as a practical alternative to radiolabeled immune reagents. An improved technique for the production of enzyme-antibody conjugates was developed that involves oxidizing the carbohydrate moieties on a glycoprotein enzyme, then introducing antibody in the presence of polyethylene glycol (PEG). Covalent enzyme-antibody conjugates involving alkaline phosphatase and amyloglucosidase were produced and characterized.^ In order to increase the sensitivity of detecting the amyloglucosidase-antibody conjugate, an enzyme cycling assay was developed that measures glucose, the product of maltose cleavage by amyloglucosidase, in the picomole range. The increased sensitivity obtained by combined usage of the amyloglucosidase-antibody conjugate and enzyme cycling assay was then compared to that of conventional enzyme immunoassay (EIA).^ For immune complex isolation, polystyrene tubes and protein A-bearing Staphylococcus aureus were evaluated as solid phase matrices, upon which antibodies can be immobilized. A sandwich-type EIA, using antibody-coated S. aureus, was developed that measures human albumin (HSA) in the nanogram range. The assay, using an alkaline phosphatase-anti-HSA conjugate, was applied to the determination of HSA in human urine and evaluated extensively for its clinical applicability.^ Finally, in view of the clinical significance of alpha-fetoprotein (AFP) as an oncofetal antigen and the difficulty with its purification for use as an immunogen and assay standard, a chemical purification protocol was developed that resulted in a high yield of immunochemically pure AFP. ^
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Fluorides are used in dental care due to their beneficial effect in tooth enamel de-/remineralization cycles. To achieve a desired constant supply of soluble fluorides in the oral cavity, different approaches have been followed. Here we present results on the preparation of CaF2 particles and their characterization with respect to a potential application as enamel associated fluoride releasing reservoirs. CaF2 particles were synthesized by precipitation from soluble NaF and CaCl2 salt solutions of defined concentrations and their morphology analyzed by scanning electron microscopy. CaF2 particles with defined sizes and shapes could be synthesized by adjusting the concentrations of the precursor salt solutions. Such particles interacted with enamel surfaces when applied at fluoride concentrations correlating to typical dental care products. Fluoride release from the synthesized CaF2 particles was observed to be largely influenced by the concentration of phosphate in the solution. Physiological solutions with phosphate concentration similar to saliva (3.5 mM) reduced the fluoride release from pure CaF2 particles by a factor of 10-20 × as compared to phosphate free buffer solutions. Fluoride release was even lower in human saliva. The fluoride release could be increased by the addition of phosphate in substoichiometric amounts during CaF2 particle synthesis. The presented results demonstrate that the morphology and fluoride release characteristics of CaF2 particles can be tuned and provide evidence of the suitability of synthetic CaF2 particles as enamel associated fluoride reservoirs.
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The preparation of LiNbO3:Er3+/Yb3+ nanocrystals and their up-conversion properties have been studied. It is demonstrated that polyethyleneimine- (PEI) assisted dispersion procedures allow obtaining stable aqueous LiNbO3:Er3+/Yb3+ powder suspensions, with average size particles well below the micron range (100–200 nm) and the isoelectric point of the suspension reaching values well above pH 7. After excitation of Yb3+ ions at a wavelength of 980 nm, the suspensions exhibit efficient, and stable, IR-to-visible (green and red) up-conversion properties, easily observed by the naked eye, very similar to those of the starting crystalline bulk material.
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Polymer nanocomposites, specifically nanoclay-reinforced polymers, have attracted great interest as matrix materials for high temperature composite applications. Nanocomposites require relatively low dispersant loads to achieve significant property enhancements. These enhancements are mainly a consequence of the interfacial effects that result from dispersing the silicate nanolayers in the polymer matrix and the high in-plane strength, stiffness and aspect ratio of the lamellar nanoparticles. The montmorillonite (MMT) clay, modified with organic onium ions with long alkyl chains as Cloisites, has been widely used to obtain nanocomposites. The presence of reactive groups in organic onium ions can form chemical bonds with the polymer matrix which favours a very high exfoliation degree of the clay platelets in the nanocomposite (1,2)
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Authors proposed an MSc Program related to Environmental Security and Management. This program endeavors to prepare students for the regional and global postgraduate job market.
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As the first step of a research program aimed at developing a bispecific monoclonal antibody system for the delivery of boron-rich molecules to tumor cells for boron neutron capture therapy, monoclonal antibodies (mAbs) were produced against an anionic nido-carborane derivative, 4-[7,8-dicarbadodecahydroundecaborat(-1)-7-yl]butanoic acid. Two IgG subclass mAbs, designated HAW101 and HAW102, were identified that specifically bound the anionic nido-carborane hapten, as well as a variety of other anionic nido-carborane cage derivatives. By using surface plasmon resonance technology, the affinity constants of HAW101 and HAW102 were determined to be 1.9 x 10(9) and 6.8 x 10(8) M-1, respectively. A diverse array of 7-substituted and 7,8-disubstituted anionic nido-carborane derivatives reacted with the mAb HAW101 in competition ELISA, whereas anionic closo-polyhedral boranes showed negligible binding, suggesting a role for the open nido-carborane cage structure. These results suggest that mAbs such as HAW101, which bind anionic nido-carboranes, are useful in the development of bispecific mAbs for specific targeting and enhanced boron delivery to tumor sites.
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Includes index.
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Attributed to Charles F. Crosman. Cf. Richmond, M.L.H. Shaker literature.
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"This report represents a cooperative study between the Bureau of mines, Department of commerce, and the College of mines, University of Washington."
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Running title: Lignite investigations, 1918 to 1925.