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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
611

Analysis of solution-phase macromolecular materials by diffusion NMR

Eden, E. G. January 2017 (has links)
Molecules such as covalent cages can adopt several shapes, in which the ratio of starting materials is the same, but the number of starting materials, and the shape of the resulting molecule is different. However, determining this in the absence of a crystal structure can be challenging. Pulsed field gradient (PFG) NMR has been used for two decades to characterise large macromolecules in solution, but it is still difficult to determine precise structural information, because of the rotational-averaging experienced in experimental measurements. Here, we develop experimental techniques for collecting PFG-NMR data that break this barrier, and allow characterisation of several useful molecular descriptors. By measuring the diffusion coefficients of molecules in a range of solvents, incurvate surfaces are probed to map the outer surface of nanometre-sized molecular species. This technique allows details about the geometrical shape of covalent cages to be determined without the need for isolation. Furthermore, we compare experimental PFG-NMR data to structures produced by computational modelling and produce a new molecular descriptor, ρr, which describes the isotropy of covalent cages. This descriptor is used to determine the quality of agreement between proposed structures and experimental PFG-NMR data. In analysing polymers, we develop a new mathematical model for determining the molar-mass dispersity (ÐM) by PFG-NMR. We find a single parameter is sufficient to determine the dispersity of a system, which eliminates the need for data modelling and enhances the reliability of analysis. We hope this will make the technique more accessible to polymer scientists, and will help test the validity of molar-mass dispersity measurements made by other means. Finally, we synthesise five novel dodecaamide cages, which contain functional groups that offer the opportunity to extend functionality beyond the cage via further reaction. We take significant steps towards producing singly functionalised species, which could be incorporated into polymeric materials for the development of robust membranes and coatings.
612

Plasmids from thermus species

Koh, Chong Lek January 1981 (has links)
No description available.
613

Genome structure and function of some viruses of Gaeumannomyces graminis var. tritici

Romanos, M. A. January 1981 (has links)
No description available.
614

Activation of cellular genes following transformation by Simian virus 40

Scott, M. R. D. January 1982 (has links)
No description available.
615

The synthesis of viral tumour antigens in SV40-transformed mouse cells

Lovett, M. January 1982 (has links)
No description available.
616

Mechanism of gene duplication in Klebsiella aerogenes

David, P. J. January 1983 (has links)
No description available.
617

Enzymes associated with mannitol metabolism in the sporophore of Agaricus bisporus (Lange) Imbach

Morton, N. I. January 1984 (has links)
No description available.
618

Biochemical and biophysical studies of haemosiderin and ferritin

Weir, M. P. January 1984 (has links)
No description available.
619

The effects of defoliation by Plutella xylostella Lon, the growth and the yield of Brassica rapa L

Barrow, Wendy Elizabeth Richings January 1986 (has links)
No description available.
620

DNA methylation and gene-expression in Chinese hamster ovary cells

Gounari, F. January 1986 (has links)
No description available.

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