Miniaturised space plasma analysers allow for lower cost plasma measurements for space science and for space weather monitoring applications; further miniaturisation will make possible nanosat-scale plasma instruments. Small instruments produced in large numbers are ideal for very-large-scale swarm and constellation missions. The field of MEMS (micro-electro-mechanical systems) potentially enables all these possibilities. This thesis introduces these themes and describes the conception and development of CATS (Cylindrical And Tiny Spectrometer), an instrument designed with MEMS in mind. CATS uses an innovative, highly-miniaturised, concentric cylindrical geometry that is able to measure simultaneously, multiple energies of both electrons and ions in space plasmas. A prototype of a CATS analyser head has been fabricated – the critical electrodes by electron discharge machining – and has been demonstrated with 30 eV to 8 keV electrons in a laboratory environment. A CEM (channel electron multiplier) and a CCD (charge coupled device) have been adapted for use with the prototype. The CCD is a back-illuminated, ion-implanted device that has been used to detect electrons directly—the first known use of such a device in an analyser instrument. The prototype design has also been extensively modelled using SIMION charged particle ray-tracing simulations, run within a tool-kit of specially created and highly sophisticated IDL automation and analysis routines. This has revealed the focussing properties of the design and options for improvements. The experimental results were compared with the simulation results and discrepancies were revealed that suggested deviations from the design specification. These deviations were confirmed, in part, by a visual inspection. Recommendations for future work and possible applications of the instrument are discussed, including the destination of the current CATS prototype and CCD detector: PoleCATS, a student-led, educational project to develop a low-altitude sounding rocket instrument.

Gold nanoparticles are promising tools for cancer therapy and cell imaging due to their non-toxicity, high heat conduction and tunable optical properties for the infraredvisible region. Nanoparticles production often involves thermal annealing, a process that changes the structure of the nanoparticle by mechanisms that are not yet well understood. For any of the biomedical applications, the nanoparticles are organically-coated to allow targeting and efficient uptake by cancer cells. Once the nanoparticles are inside the cell, their optical tunability allows the use of specific wavelengths strongly absorbed or scattered by the particles but poorly interacting with the medium to induce hyperthermia or obtain an image of the cell. In any case, the nanoparticle is expected to heat up. Although the propagation of heat is well understood at the macroscale, the details of the heat transfer at the nanoscale are still poorly understood. In this work, we use classical, equilibrium molecular dynamics simulations to create nanoparticles and investigate how their crystalline structure and the number and type of defects evolves as a function of annealing conditions. We use both analytical methods and classical non-equilibrium molecular dynamics simulations to investigate the effects of the particle size and the type of interface on the heat transfer properties of bare and organic-coated gold nanoparticles embedded in water. Water was chosen to mimic the cellular medium because it is the most abundant cellular component. Our simulations with a slab system of water and gold suggest that the material present at the interface between the gold and the water affects the heat transfer in the system. Moreover, our analytical calculations and computational results indicate that the heat transfer is dominated by the heat conduction in the medium for large nanoparticles, while for smaller nanoparticles the interface controls the overall heat propagation.

本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第5386号 / 工博第1277号 / 新制/工/901 / UT51-93-F143 / 京都大学大学院工学研究科電子工学専攻 / 学位規則第4条第1項該当

The purpose of this thesis was to elucidate the socio-economic benefits of international collaboration in scientific research. The proportion of internationally co-authored papers is increasing. This increase in co-authored papers indicates an increase in international collaboration of the actual scientific research being conducted. There are various mechanisms available in the UK which support scientific collaboration with researchers in other countries, however, there is recognition that a more strategic approach is required for international scientific engagement and that there are important social and economic considerations, beyond the benefits to the research process, that governments should consider (GSIF, 2006). This thesis aims to contribute to this debate by analysis of what the benefits are to researchers from collaborating internationally, and also what benefits may be achieved by institutions, and countries, with the focus being on the international engagement of the UK. A literature review was initially conducted. The economic rationales for publicly funded research, particularly the evolutionary rationales, are discussed, before focusing on the issues regarding international collaboration in publicly funded research, and then the techniques and indicators used to study international science. From the findings in the literature review a set of issues were identified and a theoretical framework constructed to analyse. Questionnaires from evaluations of British Council international exchange programmes for researchers were analysed to gain a better understanding of what motivates researchers to collaborate internationally, and what it is that they actually gain from such collaborations. For an understanding of why the government and national agencies support international collaboration, policy officials in the UK Government, UK Research Councils, and non-governmental organisations where interviewed. A case study was undertaken to test the initial findings in more detail. Stem cell research was chosen as a research area to use as a case study as it had many similarities with the UK position overall in scientific research, and further characteristics which made it a suitable case. A questionnaire survey, and follow-up interviews, was conducted with stem cell researchers, based in the UK and abroad. The research has confirmed many of the benefits that researchers have to collaborate internationally which were evident in the literature. These are predominately concerned with accessing knowledge, or equipment which they would not otherwise have access to. How researchers utilise their networks has also been found to be important. Hard economic benefits have been difficult to identify. However, there are benefits that accrue to a country such as awareness and visibility of the research system which can assist in attracting the best students and researchers. Finally there are the benefits that accrue to the individual researchers aggregating to national level benefits.

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Mupirocin, a polyketide antibiotic active against Gram-positive bacteria is used clinically for treatment of bacterial skin infections, to clear Stapylococcus aureus ftom nasal passages and as a surgical scrub to inhibit bacterial growth, particularly that of MRSA. Mupirocin is synthesised by polyketide synthases (PKS) in a series of reactions involving many enzymes encoded by genes from the mupirocin cluster. The mupirocin cluster consists of six larger ORFs (mmpA-F. ) encoding multifunctional proteins, and twenty nine individual genes (mupA-X and macpA-E) all of which have been shown to be required for normal mupirocin biosynthesis and presumably create a biosynthetic assembly line. Sub-groups of mutants produce identical novel metabolites implying the presence of multi-protein complexes. To determine the interactions between proteins of the Mup assembly line Bacterial and Yeast Two Hybrid Systems were used but no evidence has been provided that tested proteins are partners. Although no interaction has been revealed, complementation studies suggest that MupE protein requires coexpression of MupD protein to be functional. Furthermore, inactivation of MupD by amino acid substitution suggests that MupD is not essential on its own for any step in mupirocin biosynthesis except for the proper function of MupE protein. BPLC analysis of wild type P. fluorescens overexpressing mupOlmacpElUIVICIF in trans showed that this did not abolish PA-B production as had been hypothesised but did increase production of total antibiotic (PA-A and PA-B) up to more than two-fold indicating a need to modify our model for the production of PA-B. Results using fluorescence microscopy demonstrate that small Mup proteins are not localized within the bacterial cell and that they are spread evenly in the cells of P. fluorescens.

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