Global ETD Search
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 75 for “"Coumarin"”.
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A Comparison of Theoretical and Actual Coumarin Exudation Under Iron Limitation to Understand Root Exudation Mechanics
… weight metabolites, including iron-fixing coumarins (scopoletin, fraxetin, etc.) are primarily exuded passively, and high molecular weight metabolites follow an active exudation approach. Scopoletin and scopolin exudation from Arabidopsis thaliana in low-iron and replete conditions is …
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Reversibly Photo-Crosslinkable Polycarbonate-Based Polymersomes for Drug Encapsulation and Delivery
… (PEG-PC) copolymers functionalized with pendant coumarin groups. Coumarin groups undergo photo-reversible dimerization when irradiated with specific ultraviolet wavelengths, so they can be used to prepare polymers with photo-responsive properties. In this case, the pendant coumarin groups enable …
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Synthesis and Characterization of Tailored Photoactive Macromolecules
Coumarin and cinnamate derivatives were positioned as either polymer chain ends or side groups to synthesize photoactive macromolecules and gain the ability to reversibly control molecular weight and crosslink density using UV light. The cinnamates and coumarins were reacted onto the polymers via …
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Design and applications of 4-yl-(methyl)coumarins and their derivatives
… Another photofuse, known as the 4-yl-(methyl)coumarin, is of particular interest because of its rapid photochemical response, lack of reactive products upon UV exposure, and many different photofuses are readily prepared from inexpensive, commercially available starting materials. A divergent …
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Towards the total synthesis of novenamine and its analogues with modifications at C-4 and C-5
… glycosidically linked to a 4-hydroxy-3-amino-coumarin unit. Its activity as a DNA-gyrase inhibitor and the absence of analogues containing 4-epi-noviose provided the rationale for developing new synthetic routes to these analogues. This thesis describes the total synthesis of the methyl …
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A fragment based approach to the development of novel antibacterial agents inspired by the natural product simocyclinone D8
… by exploring chlorination reactions of dihydroxycoumarins and their corresponding starting reagents. Additionally, there was a need to establish a viable route towards the complex polyketide scaffold. Secondly, to generate a library of coumarins and screen for a low molecular weight fragment that …
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Thermally Activated Delayed Fluorescence Emitters: Molecular Design, Photophysics, and Sensing Application
… including chemical sensing. In this thesis, coumarin-based donor-acceptor systems are investigated as a versatile platform for the development of TADF-active emitters and their integration into functional sensing materials. Following an overview of the photophysical principles governing …
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Rational design and directed evolution of probe ligases for site-specific protein labeling and live-cell imaging
… of an LplA variant that can ligate a blue coumarin fluorophore onto a 13-amino acid LplA acceptor peptide (LAP2). This "coumarin ligase" can be used to image cellular proteins with high specificity, sensitivity, and minimal perturbation of the biology of the protein of interest. We also …
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Development of Molecular Glasses for Solvent-Free Photolithography utilizing Combinatorial Vapor Deposition
… sectors. 2.) Newly synthesized, self-reactive coumarin derivatives were explored in regard to their suitability for an all-dry photolithography process. When exposed to wavelengths above 300 nm, many coumarin derivatives undergo a [2+2] cycloaddition. Depending on the number of functional …
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Dye-doped polymer nanoparticles for flexible, bulk luminescent solar concentrators
… was found to be 8 7% for lwt%/lwt% doping of Coumarin 1 (C1) and Coumarin 6 (C6). In the solid state, however, energy transfer is lost, reducing to 32.8% and 20.1% respectively for the C1(lwt%)/C6(lwt%) and C1(0.5wt%)/C6(lwt/ ) iterations, respectively. Presumably, the dyes leach out of the …
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Mechanisms of Enzyme Neofunctionalization in Plant Specialized Metabolism
… for the neofunctionalization of coumarin synthase (COSY) that catalyzes the isomerization and lactonization in coumarin biosynthesis. This study unveils the emergence of an unconventional catalytic mechanism mediated by a BAHD-family enzyme, and sheds light on its recruitment to …
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Enzyme-mediated labeling of proteins and protein-protein interactions in vitro and in living cells
… small molecule probes including lipoic acid and coumarin fluorophores. We utilized LpIA and its substrate, the LAP peptide, to create sensors for proteinprotein interactions. If LpIA is fused to one protein and LAP is fused to another, only when the two proteins interact do LpIA and LAP come into …
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New extended methine dyes for application in laser technology
… saturable absorption properties of certain coumarin and long chain polymethine dyes, the synthesis of new related structures was undertaken in order to examine the relationships between structure and RSA activity. It was hoped that in this way, more effective RSA chromophores could be …
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Applications of supercritical fluid technologies to the analysis of food components
… applications related to carbohydrate, lipid, and coumarin derivative analyses. The peracetylated nitrogen derivatives of carbohydrates were analyzed by supercritical fluid chromatography (SFC) with flame ionization detection (FID), Fourier-transform infrared (FT-IR) detection, and mass …
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Optical Pumping of Dye Lasers Using an Array of Plasma Pinches
… laser pulse is obtained from rhodamine 6G, coumarin 480, LD-490, and coumarin 504 dyes.
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The preparation of cucurbit[8]uril-based hydrogels for delivery applications
… preparation and application of hydrogels using a coumarin derivative as guest. The effect of the degree of guest functionalisation, concentration of the polymer, molecular weight of the polymer, and concentration of the host molecule on mechanical properties is investigated. Furthermore, coumarin …
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Synthesis Of 1,4-Triazolyl Combretacoumarins As Potential Anticancer Agents
<p>Coumarins are natural compounds that have various physiological and therapeutic properties, making them pharmacologically important. Combretastatin A-4 (CA-4) is a microtubule-binding agent that has potent cytotoxic effects against human cell lines. In CA-4 the trimethoxyarene moiety plays a …
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Development of Green Subcritical Water Separation Technology
… water conditions. The stability of vanillin and coumarin in subcritical water was studied at 100-250 C. Vanillin was stable up to 60 min at all temperatures tested. While coumarin was stable at temperatures up to 150 C, it started to degrade at 200 and 250 C after heating for 60 min. Vanillin …
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Supramolecular Approaches to Viscoelastic Biomaterials and Their Applications
… bioelectronics. The final work describes a new coumarin-based monomer that can be incorporated into the various free-radical-polymerised and-crosslinked materials to achieve reversibly phototuneable viscoelasticity. Harnessing coumarin’s UV wavelength-dependent cyclo-additionvi and-reversion, an …
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