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Approved for public release; distribution is unlimited / Theory and simulations of the railgun and free electron laser are presented, as well as a suggestion for extending the railgun lifecycle. The theory, design, and analysis of an electromagnetic railgun using a numerical model are discussed. The effects of varying electrical pulse formations, rail materials and geometries are explored. The application of a metallurgical process to mitigate hypervelocity gouging in railgun rails is proposed. This concept, to delay the onset velocity of gouging by laser-peening rails surfaces, may significantly increase the velocity at which projectiles acceptably traverse the barrel and extend the useful life of rails. If successful, this process would apply to any pair of materials in sliding contact at high relative velocity, including rocket sled tracks and light gas guns barrels. The status of proof-of-concept tests at LLNL, UC Davis, and UT is covered. FEL simulations investigating the effect that electron beam focal point variations have on the optical mode within the undulator are presented. / Lieutenant, United States Navy

by Chan Wah Lun. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 252-260). / Acknowledgments --- p.i / Abstract --- p.ii / Contents --- p.vi / Naming of TCS mutants and modified TCS protein --- p.x / Abbreviations --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Physical and chemical properties of Trichosanthin --- p.1 / Chapter 1.2 --- Biological activities of Trichosanthin --- p.3 / Chapter 1.3 --- Renal tubular reabsorption and nephrotoxicity of Trichosanthin --- p.10 / Chapter 1.4 --- Objective and strategies of study --- p.11 / Chapter Chapter 2 --- Materials and methods --- p.19 / Chapter 2.1 --- General Techniques --- p.19 / Chapter 2.2 --- Site directed mutagenesis of Trichosanthin --- p.21 / Chapter 2.3 --- DNA sequencing --- p.37 / Chapter 2.4 --- Overexpression of modified Trichosanthin in E. coli --- p.42 / Chapter 2.5 --- Purification of modified Trichosanthin --- p.43 / Chapter 2.6 --- Breaking of Disulphide bridge between modified TCS --- p.44 / Chapter 2.7 --- Coupling of DX T40 to modified Trichosanthin --- p.44 / Chapter 2.8 --- Biological activities of modified Trichosanthin and Dextran-modified trichosantin conjugates --- p.46 / Chapter 2.9 --- Immunogenicity of modified Trichosanthin and Dextran-trichosanthin conjugates --- p.50 / Chapter 2.10 --- Nephrotoxicity of Trichosanthin and Dextran-trichosanthin conjugates --- p.53 / Chapter Chapter 3 --- Construction of TCS mutants --- p.61 / Chapter 3.1 --- Introduction --- p.61 / Chapter 3.2 --- Method --- p.61 / Chapter 3.3 --- Results --- p.62 / Chapter 3.3.1 --- Construction of K173C mutant --- p.62 / Chapter 3.3.2 --- Construction of R29C mutant --- p.64 / Chapter 3.3.3 --- Construction of K173C R29C double mutant --- p.65 / Chapter 3.4 --- Discussion --- p.66 / Chapter Chapter 4 --- "Expression,Purification and Ribosome- inactivating activities of Modified Trichosanthin proteins" --- p.87 / Chapter 4.1 --- Introduction --- p.87 / Chapter 4.2 --- Method --- p.87 / Chapter 4.3 --- Results --- p.88 / Chapter 4.3.1 --- "Expression, purification and ribosome-inactivating activity of K173C" --- p.88 / Chapter 4.3.2 --- "Expression ,purification and ribosome-inactivating activity of R29C" --- p.89 / Chapter 4.3.3 --- "Expression, purification and ribosome-inactivating activity of K173C R29C" --- p.90 / Chapter 4.4 --- Discussion --- p.91 / Chapter Chapter 5 --- Coupling of Dextran T40 to modified Trichosanthin --- p.108 / Chapter 5.1 --- Introduction --- p.108 / Chapter 5.2 --- Method --- p.109 / Chapter 5.3 --- Results --- p.109 / Chapter 5.3.1 --- Coupling of R29C --- p.109 / Chapter 5.3.2 --- Coupling of K173C --- p.111 / Chapter 5.3.3 --- Coupling of R29CK173C --- p.111 / Chapter 5.4 --- Discussion --- p.111 / Chapter Chapter 6 --- Biological Activities of modified Trichosanthin and Dextran-modified trichosanthin conjugates --- p.128 / Chapter 6.1 --- Introduction --- p.128 / Chapter 6.2 --- Method --- p.128 / Chapter 6.3 --- Results --- p.130 / Chapter 6.3.1 --- In vivo Biological activity- Mid-term abortifacient activity --- p.130 / Chapter 6.3.2 --- In vitro biological activities / Chapter 6.3.2a --- Ribosome-inactivating activity --- p.131 / Chapter 6.3.2b --- Anti-tumour activity --- p.132 / Chapter 6.4 --- Discussion --- p.133 / Chapter Chapter 7 --- Immunogenicity of Dextran-modified trichosanthin conjugates --- p.156 / Chapter 7.1 --- Introduction --- p.156 / Chapter 7.2 --- Method --- p.157 / Chapter 7.3 --- Results / Chapter 7.3.1 --- Immunogenicity without denaturation of protein --- p.158 / Chapter 7.3.2 --- Immunogenicity with denaturation of protein --- p.161 / Chapter 7.4 --- Discussion --- p.162 / Chapter Chapter 8 --- Nephrotoxicity of Trichosanthin and Dextran-Trichosanthin conjugates --- p.199 / Chapter 8.1 --- Introduction --- p.200 / Chapter 8.2 --- Method --- p.202 / Chapter 8.3 --- Results --- p.202 / Chapter 8.3.1 --- Functional study on nephrotoxicity of Trichosanthin --- p.202 / Chapter 8.3.2 --- Morphological study on the nephrotoxicity of Trichosanthin --- p.203 / Chapter 8.3.3 --- The effect of coupling of Dextran T40 on the nephrotoxicity of Trichosanthin --- p.206 / Chapter 8.4 --- Discussion --- p.207 / Chapter Chapter 9 --- General Discussion --- p.244 / References --- p.252

Transcriptional regulation is a determinant of stability of recombinant protein production in CHO cells. Fundamental studies of recombinant gene transcription in relation to chromatin environment and promoter regulation are important for CHO cell line development and selection. This study has developed a methodology based on a cell/vector system to study recombinant transcription and expression stability of different promoters and/or proteins in the similar genomic environment. The CHO-FRT mini-pools developed in this project were mini-pools of CHO-S cell lines containing Flp Recombination Target (FRT) sites with ß-galactosidase gene, under the influence of a SV40 promoter. Continuous culture of these mini-pools for 8 weeks using a robotic system demonstrated that 20% of the mini-pools studied revealed an unstable profile (with 30% loss of protein expression). Two of these mini-pools with different characteristics, CHO-FRT 1 (low producer/unstable) and CHO-FRT 108 (high producer/stable), were selected to be used on the study of influence of SV40 and CMV promoters in long-term recombinant expression. Genes encoding fluorescent proteins were integrated in a site-directed manner under the influence of SV40 or CMV promoters. A sub-clonal population of the top 10% yellow fluorescent protein (YFP) expressing cells of each mini-pool/promoter combination was selected by cell sorting and cultured for 4 weeks. During this period protein expression was monitored by flow cytometry and compared between both promoters. The results revealed that both SV40 and CMV promoters had an unstable expression with different degrees of instability and long-term expressing behaviours. For CMV, instability was considerably high displaying a long-term logarithmic loss of 50-80% of productivity while for SV40 the loss of productivity observed was only 40-45% with a linear behaviour during long-term culture. The vector system generated contained an MS2-RNA tag sequence cloned 3'- of the recombinant gene to track the recombinant mRNA by using the MS2/MCP-GFP system. This study showed the development of a protocol to measure the transcriptional output of recombinant promoters in CHO cells. The results showed background signal in CHO cells that requires further optimisation studies to allow the direct live cell image quantification of the transcriptional activity of recombinant promoters. Although not yet optimised, the successful combination of site-directed integration with recombinant mRNA tagging method has the potential to become a valuable tool to study the mechanisms of transcriptional activity and stability of transcription driven by different promoters in CHO cells.

Throughout this study, I investigate the interaction that occurs between a parent and her child when creating a collaborative drawing. The purpose of this study is to find ways in which to change common images of children and their capabilities in forming and making decisions, problem solving and communication skills, and imaginative story telling abilities. This research seeks to answer some of the following questions: In what ways are children and adults influenced by the child taking ownership of the artmaking experience and how does giving the child ownership and control over the experience change the experience for the adult? I observe two mothers as they collaborate with their young sons (ages 3 and 4) to create a drawing, discuss their experience with them and analyze their final images. Utilizing these methods, I uncover common themes and ideas about the view that adults have of children and ways of shifting these ideas of power and control over to children. I provide my recommendations and implications for the field of early childhood art education and offer a guide for parents when working with their young children.