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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"hydroxybenzoic acid"”.
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Rheological characterizaton, and the development of molecular orientation and texture during flow for a liquid crystalline copolymer of para- hydroxybenzoic acid and polyethylene terephthalate
… polymers. These include a copolyester of para-hydroxybenzoic acid and polyethylene terephthalate, and an anisotropic solution of 12 weight% Kevlar in 100% sulfuric acid. It was found that in the case of the copolyester system, the steady shear and dynamic viscosities were equal over certain …
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Aspects of natural product chemistry: Biosynthesis, structure elucidation and HSCCC/MBI/FABMS
… carboxylic acid by X-ray crystallography. Through the intermediacy of 4-methoxysalicylic acid, cremeomycin was shown to be biosynthesized by a $\rm C\sb2+C\sb2+C\sb3$ pathway in contrast to 3-amino-5-hydroxybenzoic acid and 3-aminobenzoic acid, which are made …
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A study of processing methods for producing biaxial orientation in thermotropic liquid crystalline polymers
… and properties in two thermotropic copolyesters: hydroxybenzoic acid-co-polyethylene terephthalate (HBA/PET) and hydroxybenzoic acid/2, 6 hydroxynaphthoic acid (HBA/HNA). They consisted of solid phase forming, extrusion blow molding, biaxial stretching, and film blowing. Some measure of biaxial …
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Isolation, structure, synthesis, and biosynthesis of selected bioactive microbial metabolites
… of the streptovaricins was shown to be 3-amino-5-hydroxybenzoic acid (AHBA) through carbon-14 and carbon-13 labeling studies. ($Carboxy$-$\sp{14}$C) AHBA was incorporated at a rate of 0.1% into streptovaricin C, and ($carboxy$-$\sp{13}$C) AHBA gave an enrichment factor of 21 for the resonance …
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The role of repulsive interaction in molecular self-assembly on insulating surfaces
… quantification. For this, the model system of 3-hydroxybenzoic acid on the calcite(104) surface is investigated with atomic force microscopy in an ultrahigh vacuum at different temperatures and degrees of surface coverage. The adsorbed 3-hydroxybenzoic acid molecules self-assemble into …
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Cloning, Expression, and Biochemical Characterization of Recombinant Putative Glucosyltransferases Clone 3 and 8 from Grapefruit (Citrus paradisi)
… indicate GT activity with 6 substrates, p-hydroxybenzoic acid, vanillin, vanillic acid, p-hydroxyphenylpyruvate, gentisic acid, and catechol. A second project designed to clone putative PGT8 into the Pichia expression system has been completed.</p>
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Synthesis of a renewable sourced thermotropic polyester with 2,5-furandicarboxylic acid
… derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline …
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Synthesis and Computational Studies on Hiv-1 Integrase Inhibitors
… and biological evaluation of 3-keto salicylic acid chalcones as novel HIV-1 IN inhibitors. In the chalcone series, the most active compound, 5-bromo-2-hydroxy-3-[3-(2,3,6-trichloro-phenyl)- acryloyl]-2-hydroxybenzoic acid (96) was selectively active against IN strand transfer (ST) with IC50 of …
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Antioxidant activity and phytochemical evaluations of selected medicinal plants
… in the isolation of 3,5-di-caffeoylquinic acid (3,5-DCQA), axillarin and luteolin. 3,5-DCQA appeared to be the most abundant and most antioxidant-active compound (yield = 7.28%, IC50 = 9.7 μM). The potent antioxidant activity is in support of the traditional use of the herb for fever, …
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Analysis and Engineering of Polyene Biosynthesis in Actinomycetes
… The starter unit was identified as 3 hydroxybenzoic acid by expression and assay of the chorismatase gene ftcR. Deletion of ftcR abolished flavatericin production. One flavatericin component was purified to homogeneity and subject to NMR analysis. Chapter 7 summarises conclusions, and …
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Cyclodextrin complexes of antimicrobial agents
… were chlorhexidine dihydrochloride (CHX), p-hydroxybenzoic acid esters (methyl, ethyl, proply and butyl) and triclosan. The interactions between the antimicrobials and CyDs were studied in solution and solid phases. Phase solubility studied revealed an enhancement in the aqueous drug …
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Formation, Characterization and Stability of Natural Antimicrobial-Cyclodextrin Complexes
… five compounds are alkyl esters of para-hydroxybenzoic acid. The test compounds were evaluated for aqueous solubility as well as their solubility in an acid-based beverage mixture. The compounds were found to be practically insoluble (< 100 mg/L), very slightly soluble (100 mg/L – 1,000 …
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Transport of Liquid Phase Organic Solutes in Liquid Crystalline Membranes
… demonstrated enhanced permeation selectivity for hydroxybenzoic acid and aminophenol isomers primarily due to increased sorption selectivity. Shape selective absorption of rod-like para-isomers in the nematic phase was observed in both 8CB and PCH5 LCs. A nonchiral based HPLC-CD (High Performance …
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Development of bio-composites with novel characteristics through enzymatic grafting
… various natural phenols e.g., caffeic acid (CA), gallic acid (GA), p-4-hydroxybenzoic acid (HBA), and thymol (T) were grafted onto the newly developed P(3HB)-EC and keratin-EC-based composites under laccase-assisted environment. Subsequently, the resulting bio-composites were removed …
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Part I: Synthesis of Aromatic Polyketones Via Soluble Precursors Derived from Bis(A-Amininitrile)S; Part Ii: Modifications of Epoxy Resins with Functional Hyperbranched Poly(Arylene Ester)s
… polyaminonitriles, which were hydrolyzed in acidic conditions to produce the corresponding polyketones. A novel approach to the synthesis of high molecular weight wholly aromatic polyketones without ether linkages or alkyl substituents in the polymeric backbones was demonstrated. These …
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Investigating co-crystallisation of primary amides and carboxylic acids. Comparative analysis of Benzamide, Isonicotinamide and Nicotinamide co-crystal growth with carboxylic acid.
… to the primary amide, usually carboxylic acids. The progress with regards to the screening process for the determination of co-crystals is evident in the literature, In particular, high throughput solution growth methods and solvent drop grinding. The comparison of Isonicotinamide and …
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Studies on the rheology and morphology of thermotropic liquid crystalline polymers
… polymers. These include two copolyesters of para-hydroxybenzoic acid and polyethylene terephthalate and a copolymer of para-hydroxy benzoic acid and 6-hydroxy-2-naphthoic acid. For all three systems, it was found that the viscosities at temperatures below the normal flow temperatures were reduced …
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A framework for integrating chemistry and process synthesis in the analysis of pathways for chemical manufacture
… this thesis also presents a flow sheet for mixed-acid batch nitration, reaction pathways for making various substituted benzenes, a general MILP formulation for evaluating and comparing chemical manufacturing pathways, and a review and analysis of different approaches to multiobjective …
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A study of the mechanical properties and the equilibrium nature of the blend of thermotropic liquid crystalline copolyesters
… deals with the melt blend of 60/40 PHB/PET (p-hydroxybenzoic acid and polyethylene terephthalate) and 80/20 PHB/PET copolyesters in a 50:50 weight% ratio. Specifically, the interest was to determine as to how do the mechanical properties of the injection-molded parts from the blend compare with …
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Role of Bioadditions in Sustainable Energy Production
… have an inhibitory effect. For example, syringic acid (S-unit) was metabolized and produced increased biogas yields compared to control and yeast addition significantly increased these yields. On the other hand, p-hydroxybenzoic acid, inhibited biogas production, with and without yeast addition. …
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