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 28 for “"persistence length"”.
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Unexpected mechanical properties of nucleic acids
… in many biological life processes. The bending persistence length of DNA is of specific interest, because so much eukaryotic DNA that stores genetic information is tightly packed inside cell nuclei, even though DNA is considered to be a relatively stiff biopolymer. However, recent experiments …
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Single -Molecule and Ensemble Fluorescence Studies of Single -Stranded DNA and Replication Proteins
… FRET measurements can be used to determine the persistence length of single-stranded DNA. Our results indicate that the persistence length decreases from 3.0nm to 1.5nm as the salt concentration increases from 50mM NaCl to 2M NaCl. Furthermore, we use fluoresce anisotropy and FRET measurements …
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Thermal conductivity in organic semiconducting polymers
… role in deciding its thermal conductivity. Then persistence length, which quantifies the stiffness, of these polymers in dilute solution was determined both experimentally and computationally; although this was an interesting topic on its own, no explicit correlation was found between persistence …
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Temperature and sequence dependence of DNA flexibility
DNA fragments shorter than the persistence length display about five orders of magnitude higher flexibility than predictions of the semi-flexible polymer models based on its persistence length. Via single molecule cyclization assays, flexibility of different constructs at various conditions can be …
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Nanomechanical coupling of mechanomutable polyelectrolytes
… and weak interactions, polyelectrolyte persistence length and molecular rigidity of PAA and PAH is investigated with full atomistic precision. Large-scale molecular dynamics (MD) simulations indicate the stiffening of PEMs cannot be explained by increased electrostatic cross-linking …
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Conformations of semiflexible polymers and filaments
… Semiflexible polymers are characterized by their persistence length, the definition of which is the subject of the first part of this thesis. Attractive interactions, that arise e.g.~in the adsorption, the condensation and the bundling of filaments, can change the conformation of a semiflexible …
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Biology's wires and motors : single-molecule mechanics of M13 bacteriophage and kinesin
… single-molecule elasticity, revealing a persistence length (1265 nm) that places it squarely in the semiflexible polymer regime. Single-molecule stretching also revealed a mechanically robust and genetically versatile tether that could serve as a general "molecular handle" for …
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Part I: Strategies for the Synthesis of Monodisperse Polymers and Cyclic Polymers. Part II: Synthesis of Dipyrromethenes and Aza-dipyrromethenes from Aromatic Nitriles
… of cyclic polymers, in that the relatively long persistence length of the polymers makes it unreasonable to assume 100\% cyclization. The approach presented in this chapter is meant to be as general as possible, and to have applications in other cases where polymers need to be separated based on …
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Nanoscale studies of CVD graphene and poly(3-hexylthiophene) thin films.
… the use of two methods for quantifying the persistence length of the polymer chains: edge-detection based Hough transform and the worm-like chain model. By optimizing the graphene electrode and the polymer efficiency we hope to move closer to a carbon-based replacement for bulk semiconductor …
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Multi-Level Coarse-Grained Modelling on DNA Functionalised Building Blocks
… of the double-strand DNA (dsDNA) with a persistence length of around 50nm (≅150bp) provides rigid structural properties to form the most stable duplexes. Single-strand DNA (ssDNA) with much less rigidity acts as hinges between duplex sections allowing extra flexibility to the structure. …
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Submicron Correlations Of Receptor-positions On Cell Surfaces
… present fluctuations that have a characteristic persistence length equal to the laser beam width. The calculated correlation function decays as the laser beam intensity profile which is Gaussian in nature. The zero-lag value of the properly normalised correlation function is a direct measure of …
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Dynamics and structures of linear and supercoiled DNAs
… rods comprising 10 and 30 subunits with various persistence lengths.Rapidly relaxing components in the decay of the transient electric dichroism of DNA restriction fragments reported by Diekmann et al. (Diekmann et al., 1982) and Porschke (Porschke et al., 1987) are analyzed using the new normal …
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Synthesis and Characterization of Highly Functional Substituted Stilbene Copolymers and Semi-crystalline Poly(aryl ether sulfone)s
… Dynamic light scattering, 2H solid state NMR and persistence length measurement reveal high chain rigidity of the polymer backbone. Double quantum heteronuclear local field solid state NMR spectroscopy (2Q-HLF Solid State NMR) has been employed to investigate the chain structure of ¹³C labelled …
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Synthesis and Characterization of Nanoporous Copolymers with Potential Gas Storage Applications
… Surface areas were found to increase as the persistence length increased. A series of HCPs containing functionalized stilbene and N-substituted phenyl maleimide were synthesized via free radical suspension polymerization. The incorporation of these functionalized, chain stiffening, Tg …
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Towards Synthetic Molecular Motors Interfaced by AFM
… should, by OSF-theory, change their persistence length (and therefore the overall length at a constant force) with the Debye screening length of the solvent (which is manipulated by the salt concentration). Therefore, t he elasticity of the polyelectrolyte polyvinylamine, which could …
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Deformability and Dynamics in Linear and Looped/Supercoiled DNA with Implications for Damage Sensing
… bp and 336 bp, comparable in size to ~150 bp DNA persistence length). In 126-bp relaxed minicircles, Rad4 affinity increased ~50-fold and MutS affinity ~10-fold, to their respective specific sites. Interestingly, DNA appeared more rigid in these minicircles compared to linear DNA. 336-bp …
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Single molecule fluorescence studies of biomolecular interactions
… of DNA posits that DNA must be stiff below the persistence length (<150 base pair) but recent studies addressing this have yielded contradictory results. We developed a fluorescence-based, protein-free, assay for studying the cyclization of single DNA molecules in real time. The looping rate for …
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Photophysical Studies of Beta Phase Formation in Poly(9,9-di-n-alkylfluorenes)
… formation efficacy shows an optimal side chain length of 8 carbons. The beta phase formation in PF8, PF9 and PF10 is modelled using a previously reported aggregation model, with limited success. A mechanism for the beta phase formation is proposed, where the interactions between the alkyl side …
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Computational modeling of biological molecule separation in nanofluidic devices
… For molecules that are sufficiently short (length on the order of, or smaller than, the persistence length), we developed a BD model which treats DNA molecules as rigid rods; this results in significantly reduced computational requirements. Finally, we present a further simplified BD model …
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Self-assembly of Nanoparticles on Fluid and Elastic Membranes
… elastic membrane may acquire a macroscopic persistence length and a helical conformation. We find that the filaments helical pitch is completely determined by the mechanical properties of the surface, and can be easiliy tuned. Moreover, we study the collapse of unstretchable (thin) hollow …
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