System Design, Motion Modelling and Planning for a Recon figurable Wheeled Mobile Robot

Over the past ve decades the use of mobile robotic rovers to perform in-situ scienti c investigations on the surfaces of the Moon and Mars has been tremendously in uential in shaping our understanding of these extraterrestrial environments. As robotic missions have evolved there has been a greater desire to explore more unstructured terrain. This has exposed mobility limitations with conventional rover designs such as getting stuck in soft soil or simply not being able to access rugged terrain. Increased mobility and terrain traversability are key requirements when considering designs for next generation planetary rovers. Coupled with these requirements is the need to autonomously navigate unstructured terrain by taking full advantage of increased mobility. To address these issues, a high degree-of-freedom recon gurable platform that is capable of energy intensive legged locomotion in obstacle-rich terrain as well as wheeled locomotion in benign terrain is proposed. The complexities of the planning task that considers the high degree-of-freedom state space of this platform are considerable. A variant of asymptotically optimal sampling-based planners that exploits the presence of dominant sub-spaces within a recon gurable mobile robot's kinematic structure is proposed to increase path quality and ensure platform safety. The contributions of this thesis include: the design and implementation of a highly mobile planetary analogue rover; motion modelling of the platform to enable novel locomotion modes, along with experimental validation of each of these capabilities; the sampling-based HBFMT* planner that hierarchically considers sub-spaces to better guide search of the complete state space; and experimental validation of the planner with the physical platform that demonstrates how the planner exploits the robot's capabilities to uidly transition between various physical geometric con gurations and wheeled/legged locomotion modes

Aspects of Diabetic Autonomic Neuropathy

Diabetic autonomic neuropathy is the most commonly-occurring form of autonomic nervous system dysfunction found in clinical practice. Despite the difficulties encountered in studying single control mechanisms in the presence of this disease (Introduction), it may be possible to elucidate information on physiological control of some dynamic aspects of cardiovascular and neuroendocrine influences by looking at a group of severely affected diabetics and their responses

Missed Targets: Canada's 2007 Fiscal Accountability Ranking

If governments do not meet their budget commitments, accountability to legislators and voters breaks down. How reliable have federal, provincial and territorial commitments been over the past 10 years? Overruns have been the general rule, but some governments have done much better than others.fiscal policy, government accountability

Trivalent scandium, yttrium and lanthanide complexes with thia-oxa and selena-oxa macrocycles and crown ether coordination

Complexes of the oxa-thia macrocycles [18]aneO4S2, [15]aneO3S2 and the oxa-selena macrocycle [18]aneO4Se2 (L) of types [MCl2(L)]FeCl4 (M = Sc or Y) were prepared from [ScCl3(thf)3] or [YCl2(THF)5][YCl4(THF)2] and the ligand in anhydrous MeCN, using FeCl3 as a chloride abstractor. The [MI2(L)]I, [LaI3(L)] and [LuI2(L)]I have been prepared from the ligands and the appropriate anhydrous metal triiodide in MeCN. Complexes of type [LaI3(crown)] and [LuI2(crown)]I (crown = 18-crown-6, 15-crown-5) were made for comparison. Use of the metal iodide results in complexes with high solubility compared to the corresponding chlorides, although also with increased sensitivity to moisture. All complexes were characterised by microanalysis, IR, (1)H, (45)Sc and (77)Se NMR spectroscopy as appropriate. X-ray crystal structures are reported for [ScCl2([18]aneO4S2)][FeCl4], [ScI2([18]aneO4S2)]I, [YCl2(18-crown-6)]3[Y2Cl9], [YCl2([18]aneO4S2)][FeCl4], [LaI3(15-crown-5)], [LaI2(18-crown-6)(MeCN)]I, [LuI(18-crown-6)(MeCN)2]I2, [Lu(15-crown-5)(MeCN)2(OH2)]I3, [LaI3([18]aneO4S2)], [LaI([18]aneO4S2)(OH2)]I2, [LaI3([18]aneO4Se2)] and [LuI2([18]aneO4Se2)]I. In each complex all the neutral donor atoms of the macrocycles are coordinated to the metal centre, showing very rare examples of these oxophilic metal centres coordinated to thioether groups, and the first examples of coordinated selenoether donors. In some cases MeCN or adventitious water displaces halide ligands, but not the S/Se donors from La or Lu complexes. A complex of the oxa-tellura macrocycle [18]aneO4Te2, [ScCl2([18]aneO4Te2)][FeCl4] was isolated, but is unstable in MeCN solution, depositing elemental Te. YCl3 and 18-crown-6 produced [YCl2(18-crown-6)]3[Y2Cl9], the asymmetric unit of which contains two cations with a trans-YCl2 arrangement and a third with a cis-YCl2 group

The Application of Gas-Phase Methods to the Analysis of Naturally Occurring Compounds

In the last few years, increasing interest has been shown in the related techniques of gas liquid chromatography (GLC), and combined gas chromatography and mass spectrometry (GC-MS), and in particular in the application of these techniques to the analysis of small amounts of material, such as those which may be found in natural systems. This thesis investigates the use of these techniques in two distinct fields; the first is the examination of boronic acids as reagents for the formation of derivatives of sugars suitable for GC and. GC-MS analysis, and the second is the application of the techniques to the investigation of extracts from plant tissue for the purpose of locating and identifying any compounds of a particular type which may be present in the plant. In 1968, Brooks and Watson introduced the concept of boronate esters as suitable derivatives, for GLC and GC-MS, of compounds possessing a cis bifunctionality, such as cis diols. They suggested the applicability of the derivative to carbohydrate analysis, and also showed that pregnanetriol boronate could easily be trimethylsilyated. without disturbing the cyclic ester group. Brooks and Harvey also showed, in a later paper, that triple derivatives of a compound could be made, for example, the methyl oxime of a cyclic boronate trimethylsilyl ether. In this same paper the authors demonstrated that acyclic boronates formed from isolated hydroxyl groups could be displaced by trimethylsilyation without affecting a cyclic boronate also present in the molecule. This last observation was extremely important, as it showed that excess boronic acid could be used to form a derivative of a compound and any acyclic boronates formed could be removed in this way. This was ideal for the study of compounds like sugars, where there are a number of hydroxyl groups present. Excess boronic acid could be used to form the cyclic boronates, and the compound would then be trimethylsilylated to eliminate any undesired acyclic boronates formed. The trimethylsilylation would also result in a less polar, more volatile compound which would have better GLC properties. Shortly after the inception of the present research, there appeared the first of a number of papers on this topic; these demonstrated that it was possible to use the boronates in such a way, and that where the reaction resulted in one or more hydroxyls remaining under-ivatised, it was possible to convert them to the trimethylsilyl ethers, without destroying the boronate already present, producing a mixed derivative that was suitable for GLC and GC-MS. To investigate these derivatives further, a comparison has been made of the GLC properties of the methyl-, n-butyl; and phenylboronates and boronate TMSi ethers of a number of sugars, each of which was known to be, initially, in a cyclic form, and hence to have a preferred conformation which would influence the course of the boronation reaction in which the boronic acids react only with cis-bifunctional systems. The GC-MS properties of the methyl- and phenyl- derivatives have also been studied, the difference of 62 mass units between the methyl and phenyl groups being an aid to the identification of boron-containing peaks. From the gas chromatographic data and mass spectra, and in some instances the nuclear magnetic resonance data, an attempt has been made to determine the structure of the boronates and boronate TMSi ethers formed by each sugar. The boronates, and. the boronate TMSi ethers, have been found to be good derivatives for GLC, giving sharp, non-tailing peaks on both 1% SE-30 and 1% QF-1, and though the tendency of the sugars to form multiple derivatives would make this method difficult for the routine analysis of a large number of compounds, it does simplify the identification of individual sugars by increasing the number of useful parameters characteristic of each sugar. (Abstract shortened by ProQuest.)

Morphogenesis in Inorganic Precipitates in Gels

This thesis is concerned with the precipitation of inorganic materials and in particular Induced Morphology Crystal Aggregates (IMCA's). This strange phenomenon occurs when an akaline earth metal carbonate and an alkaline earth metal silicate precipitate simultaneously in basic silica gel. The metal silicate precipitates as a sheath which acts to control the crystal-to-crystal relations of the metal carbonate aggregate and therefore the overall morphology of the precipitate. Very strange morphologies result such as sheet-like and spiral structures in the case of BaCO3. BaCO3 was studied extensively in this project. A glass cassette reaction vessel was developed in collaboration with J. M. Garcia Ruiz which enabled in-situ light microscopical analysis of morphology. Precipitates were then removed from their gels and subjected to chemical analysis and further morphological observation by scanning electron microscopy (SEM). The surface analysis techniques of energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were utilised to determine the chemical composition of the sheath or membrane which controls morphology. Some key factors which affect BaCO3 IMCA formation were established. A very clear morphogenetical transition from dendrites (normal crystal growth) through to fully induced morphologies was observed. This transition depends on the amount of soluble silicate in the gel and its ability to react with the metal and form a membrane. The main factors which affect this are pH and the presence of NaCl in the gel. High pH values promote IMCA growth. This is attributed to increased silicate ion concentrations at higher pH values. The presence of NaCl also promotes the formation of IMCA's. This may be due to charge effects stabilising the precipitating membrane. Growth mechanisms are proposed which have similarities to cement chemistry and the silica garden effect. Experiments carried out on the nature of the membrane have shown it to be a barium silicate carbonate in the region of one micron thick. Other insoluble barium precipitates such as BaSO4 (studied extensively), BaCrO4 and BaHPO4 have been found to form IMCA's suggesting that the effect may be quite widespread and experiments on iron carbonate and iron sulphide suggested that silica may influence morphology. In the case of iron sulphide, precipitates were obtained which were remarkably similar to naturally occurring iron sulphide framboids, unusual spherical aggregates recently implicated in origin of life studies

The Distribution and Characterisation of Aspartic Proteinases in Human Tissues

The aspartic proteinases are members of a family of enzymes, the catalytic activity of which depends on the presence of two aspartic residues in the active site. This thesis concerns four members of this group - pepsin, gastricsin, cathepsin D and slow moving protease (SMP). The defining characteristics, nomenclature and general biochemistry of the aspartic proteinases are reviewed in Chapter 1 and an attempt is made to clarify the various systems which have been used to classify this group of enzymes. Assay and purification methods, the structure and mechanism of action of the enzymes and their immunological properties are outlined. Pure supplies of these enzymes are not commercially available and Chapter 2 describes the method by which these were obtained and how anti sera were developed. The anti sera are used to show that cathepsin D and SMP, previously thought to be identical, are separate enzymes. In Chapter 3 the immunohistochemical methods are introduced and their use in determining the distribution of the above enzymes in normal gastroduodenal mucosa is described, at both light and electron microscopic level. It is shown that pepsinogen is mainly confined to the gastric body, while progastricsin co-localises with pepsinogen but is also present in the gastric antrum and duodenum. Cathepsin D is demonstrated in parietal cells, in gastric antral glands and cells in the lamina propria, while SMP is demonstrated mainly in the surface epithelium of the stomach. These studies raise the general problem of the effects diffusion may have on the localisation of tissue antigens. This problem appears not to have been widely discussed in the literature and is dealt with in Chapter 4, in which diffusion was studied by immunolocalisation of pepsinogen and progastricsin in autolysing gastric mucosa and confirmed experimentally by immunolabelling of antigens introduced into various normal tissues. Enzyme activity at low pH has long been recognised in seminal fluid. In Chapter 5 this is shown to be due to the presence of gastricsin, apparently identical to that in normal gastric juice. The zymogen, progastricsin, was localised to the acinar cells of the prostate, which appear to secrete and presumably synthesise it. In Chapter 6, the distribution of aspartic proteinases in normal tissues apart from stomach, duodenum and prostate is discussed. No evidence of pepsinogen or progastricsin was found in other tissues, while cathepsin D appears widely distributed both in macrophages and in epithelial cells. SMP appears to be confined to the surface membrane or cilia of a few tissues, such as chorionic villi and respiratory epithelium, but its presence even in these tissues could be derived from the red blood cells, on the membranes of which it is demonstrated. Studies on the distribution of the aspartic proteinases are extended to the fetal stomach in Chapter 7, where it is shown that SMP is the dominant enzyme from 12 weeks gestation onwards, while progastricsin becomes prominent by about 17 weeks, when pepsinogen and cathepsin D also appear. Some attempt is made to relate the order of their appearance to the molecular evolution of aspartic proteinases. The rest of the thesis deals with the presence and distribution of the aspartic proteinases in neoplastic tissues. In Chapter 8, it is shown that gastric carcinomas produce aspartic proteinases, namely cathepsin D (100%), SMP (50%), progastricsin (30%) and pepsinogen (6%). There appears to be no relation to prognosis and both intestinal and diffuse types of carcinoma contain aspartic proteinases. In Chapter 9, the studies which showed progastricsin in normal prostatic epithelium, described in Chapter 5, are extended to carcinomas, up to 40% of which produce progastricsin. Progastricsin co-localises with acid phosphatase but is, however, less widely distributed. In Chapter 10 the distribution of aspartic proteinases in non-gastric tumours is described. While pepsinogen is highly specific to gastric carcinomas, progastricsin occasionally occurs in tumours of some other sites, especially pancreas, while cathepsin D is found in almost all tumours studied. SMP appears to be present in certain tumours, mainly kidney. In Chapter 11, progastricsin is more fully studied in metastatic tumours, firstly in local lymph node secondaries near primary gastric carcinomas and secondly in deposits further afield, both in lymph node and liver, from a range of primaries in different sites. It is shown that in most cases the presence of progastricsin in a lymph node metastasis of adenocarcinoma indicates a primary in the stomach or in pancreas but that occasionally metastases from other sites contain progastricsin. While progastricsin was commonly found in liver metastases, the correlation with a primary in stomach did not reach statistical significance. These results could be useful to the diagnostic histopathologist in determining the primary site from which a given metastasis has originated. The final discussion (Chapter 12) incorporates recent evidence that the pol gene of the HIV I virus codes for an aspartic proteinase and that retroviral proteinase activity is inhibited by the aspartic proteinase inhibitor, pepstatin. Knowledge of the distribution of the aspartic proteinases might therefore be relevant to possible treatment of AIDS with aspartic proteinase inhibitors

Mass Spectrometry of Some Organic Compounds

The thesis discusses the aspects of mass spectrometry related to organic chemistry. It is primarily concerned with involatile substances which cannot be studied by conventional mass spectrometry. Chapter I is a brief introduction and deals with the development of mass spectrometry from the early positive beam studies to its use in organic analysis. A study of furan (Chapter IIA) and benzfuran (Chapter IIB) systems is then discussed in an attempt to predict fragmentation patterns of the furan ring system in simple and complex structures. The cracking pattern of simple furans is considered along with the mass spectra obtained from some naturally occurring compounds, such as marrubiin and Columbia, which contain a substituted furan ring. Many of these natural products are involatile substances and a direct inlet system is used to obtain results. Some conclusions are drawn with reference to the identification of the furan system in a molecular structure and tentative structures are proposed for some of the abundant ions produced by electron impact. Chapter III is devoted to a series of naturally occurring tetracyclic antibiotics (the pyrromycinones and rhodomycinones) which include a polyhydroxyanthraquinone system in their structure. Correlation studies of the series of mass spectra obtained have been found useful in attempts to postulate structures for some related compounds which have been studied unsuccessfully by classical organic chemists. No worker has yet been able to predict the detailed stereochemical relationships in a compound from mass spectral data alone. Chapter IV discusses the limitations of mass spectrometry in this respect and demonstrates the use of the mass spectrometer to decide the overall "crowding" in a molecule. The chapter comments on the columbin-iso-columbin isomerism, the stereochemistry of rhodomycinone and its isomer and the positional isomerism which occurs in the chlorogriseophenones. Unsatisfactory results are usually obtained from compounds which are thermally unstable or which have a highly branched structure. However, although part of the cracking pattern obtained from derivatives of malonic acid may arise by thermal decomposition, it has been found possible to determine the molecular weight of such compounds by use of ions occurring at one mass unit greater than the parent ion. Correlation of the mass spectra of these compounds is again useful in determining structural features of some compounds which contain one or more quaternary centres