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Tübingen, Univ., Diss., 2005.

Ipecacuanha had been used for many years in medical practice before Rogers (1), in 1912, showed that emetine, one of the constituent alkaloids, was a specific agent against dysentery. This discovery, in relation to the toll which the diseases takes in tropical countries, intensified the efforts of chemists to deduce the structure of the alkaloid in the hope of synthesising it. This hope was not finally achieved until 1950. The final stages in selecting the correct structure for emetine were aided by a consideration fo the possible biogenetic route to the alkaloid in the light of current theories of the biogenesis of alkaloids. In consequences of this, a detailed examination of the alkaloidal material present in the root was undertaken in the hope of isolating some compound which might be a biogenetic intermediate. The results of that investigation are described in this thesis. At the same time the opportunity was taken to study the chemistry of the minor alkaloids. The work on the structural formula of emetine had shown the marked specificity of the alkaloid in the treatment of amoebic dysentery. There are four centres of asymmetry in the molecule and inversion of the configuration at the asymmetric centres had to be ascertained. In the latter part of the thesis the initial experiments in the elucidation of the stereochemistry of emetine are described. These results and the subsequent elucidation of the stereochemistry and the stereospecific synthesis of emetine and emetamine have been reported by Dr. Battersby and his associates in a series of papers in the Journal of the Society of Chemistry and Industrial and the Journal of the Chemical Society (80)(56)(57).

1) The most recent work on the pyrolysis of dibenzyl suggested that a thermal equilibrium:- PhCH2CH2Ph == 2 PhCH2- was set up as a preliminary to decomposition. The aim of this research was to test this idea by heating mixtures of PhCH2CH2Ph (M.W. 182) and PhCD2CD2Ph (M.W. 186) and following mass spectrometrically the growth of PhCH2CH2Ph (M.W. 184) formed by radical recombination. 2) A four stage synthesis of deuterated dibenzyl was developed and used to prepare dibenzyl of 95% isotopic purity with the composition:- PhCD2CD2Ph, 81%; PhCD2CDHPh, 18 %; PhCDHCDHPh, 1%. PhCH2CD2Ph was synthesized by the same sequence of reactions. 3) In order to provide the necessary experimental equipment, the following items have been developed and constructed and descriptions of them are given in this Thesis:- a) a 2 litre reaction vessel with an electronically controlled furnace was arranged with a gas circulating system feeding the inlet of a mass spectrometer; b) an existing mass spectrometer was extensively modified in order to give resolution of 1 in 200:- i) the spectrometer tube was stiffened and accurately re-aligned; ii) the ion collector unit was made detachable and its construction improved; iii) a new ion source was designed and built to the required high accuracy; iv) a new scanning unit was built for variation of the magnetic field. 4) The rate of formation of PhCH2CD2Ph was followed in mixtures of PhCH2CD2Ph and PhCD2CD2Ph at pressures of 0.08 to 0.66 mm. in the reaction vessel, and at pressure up to 142 mm. in sealed tubes, using temperatures between 400° and 500°C. Data were also obtained on the rate of decomposition of PhCH2CH2Ph alone in similar systems. 5) The rate of radical exchange was found to be first order, independent of surface and of pressure of added A, N2, D2, and O2. The decomposition reaction was shown to be 1.5 order at low pressures, and tended to first order at high pressures. At lower pressures it was much slower than the radical exchange. 6) A rate equation for radical exchange in terms of the rate of dissociation of dibenzyl, making due allowance for the simultaneous decomposition of dibenzyl has been developed and applied in the lower pressure region where exchange was of major importance. It gives:- kf sec−1 = 10 14.03 exp -6000/RT 7) The energy of activation in 6) has been identified with D(PhCH2-CD2Ph) in dibenzyl. This value has been discussed in relation to current data on the heat of formation of the benzyl radical and bond dissociation energies in benzyl compounds, notably D(PhCH2-H) in toluene. 8) The energy of activation for the decomposition was found to be 47 kcal and the nature and proportions of the reaction products were established and compared with previous work. The proportions of side-chain deuterated toluenes formed were consistent with a deuterium isotope effect of 2 or less, and with toluene being made by the abstraction of hydrogen from the central carbon atoms of dibenzyl by benzyl radicals. Benzyl radicals were also shown to react with deuterium to form toluene.

In this thesis, a study is made of the global solar oscillations known as p-modes, modelled by a plane-parallel stratified plasma, within which is embedded a horizontal layered magnetic field. A magnetohydrodynamic formalism is used to investigate the models. The main aim of the thesis is to model the turnover effect in the frequency shifts of the p-modes observed over the course of the solar cycle. Radial oscillations (modes of degree zero) of the Sun are studied for several atmospheric temperature and magnetic field profiles. It is found that the turnover in frequency shifts may be obtained by an increase in the strength of the atmospheric horizontal magnetic field (assumed to be uniform), coupled with a simultaneous increase in atmospheric temperature. The effect of a thin superadiabatic layer in the upper convection zone on p-mode frequencies is also considered. For this model we study modes of general degree, and find that the observed rise and subsequent downturn in the frequency shifts can be duplicated, in the absence of a magnetic field, by simultaneously steepening the temperature gradient of the superadiabatic layer and increasing the atmospheric temperature. In the presence of a magnetic field, where the atmosphere is permeated by a uniform horizontal magnetic field, turnover is reproduced by a combination of an increase in magnetic field strength, a steepening of the temperature gradient in the superadiabatic region, and an increase in atmospheric temperature. The unstable superadiabatic layer also gives rise to convective modes, which are considered briefly. Finally, a model incorporating a magnetic layer residing at the base of the convection zone is constructed and its influence on the frequencies of p-modes assessed. By simply changing the magnetic field strength of this layer, we are unable to reproduce the observed solar cycle variations in p-mode frequencies. The buried magnetic layer supports surface and body magnetoacoustic waves, and a brief study is made of their properties.

The thesis deals with the concepts of Millenarianism and the witnessing of Faith through costume, textiles and related arts. The responses of five religious sects, Amish, Shaker, Puritan, Quakers and Mennonites, are examined. This text falls into two discrete sections. Chapter One details the historic background of the sects. Subsequent chapters outline the Millennial impulse of the seventeenth to the nineteenth centuries and resulting emigration to the New World. These chapters detail Utopian social models and a discussion of textiles and clothing as indicators of history and human experience. Chapter Three is an overview of religious iconography in this area of American art, touching on themes and the role in society of both the art and the artist. It discusses allegory and symbolism in the visual arts. The second half of the thesis focuses on the costume and textiles of each group. Particular consideration is given to the use of iconography, symbolism and allegory in their visual creations. Internal doctrinal differences are examined such as interpretations of the Biblical injuction to be 'plain', and the central role that the concept of being 'not conformed to the World' plays in the social/aesthetic/religious development of the sects. Apparent theological contradictions are highlighted and addressed. Pressures on each sect to adapt to the cultural norm that have resulted in change and disintegration are detailed.

Several models of animal associative learning are described. The evidence for the concept of associability is reviewed. The review contains a detailed account of blocking, including the Mackintosh, Bygrave and Picton (1977) experiment. It is shown that the two major associability models need to be modified, mathematically, to simulate the results of this experiment. A general, simple framework for investigating putative associability changes is suggested. A review of stimulus pre-exposure effects is put into this framework, and indicates a suitable direction for research. The experiments looked for associability changes of both conditioned and unconditioned stimuli. Sometimes the stimulus was a predictor of subsequent events; if not, it was predicted by another stimulus. A variety of procedures was employed. Experiments 1, 2, and 3 tried to replicate and extend previous work with a conditioned stimulus predicting subsequent events, but they were unsuccessful. Experiments 4, 5, 6, 7, and 8 investigated whether conditioned and unconditioned stimuli would change in associability when they were well predicted. Unfortunately, the data were difficult to interpret. An appetitive-aversive transfer paradigm was used in Experiments 9, 10, and 11; there was some evidence that a tone could change in associability, both when it was acting as a predictor, and when it was being predicted. Alternative Interpretations were also discussed. In Experiments 12 and 13, a shock was used to predict the occurrence of food; and there was no evidence that the associability of the shock could be increased in this way.

i. The stomatogastric nervous system of some of the decapod crustacea contains several small isolated ganglia. At least one of these ganglia is useful for the detailed investigation of the generation of a patterned central output controlling movement. A review of previous work shows that little is known of the anatomy and physiology of the sense organs innervating the foregut. This knowledge would be valuable for understanding the control mechanisms governing the foregut function because reflex mechanisms are probable important in this situation. Therefore the aim of the thesis was to investigate the mechanoreceptors innervating the foregut. Work was concentrated on these sense organs because they are probably involved directly in the control of movement. ii. The large amount of previous work on this type of sense organ in the higher decapods is summarised in an appendix. An attempt is also revise to some of the terminology used in the study oi these receptors, and recent developments are reviewed in some detail. iii. Two new major receptor systems innervating the foregut are described. The posterior stomach (p.s.n.) contains a group of about 80 neurones which innervate the posterior of the gastric mill. These neurons respond to normal movements of the mill. Changes in the input from the receptors affect the output from the stomatogastric ganglion. The other system (MPRs) consists of three distinct organs totalling about 40 neurones which monitor normal movements of the structures around the mouth iv. Suggestions are made top further specific work on these two receptor systems. What is now known of the sensory innervation of the foregut is summarised and suggestions made for completing this knowledge. v. Further possible work on the ganglia and the role the associated mechanoreceptor organs is reviewed. Finally work on other problems related to the studies reported here is discussed.

In 1967, J. A. Erdős showed, using a matrix theory approach that the semigroup Sing[sub]n of singular endomorphisms of an n-dimensional vector space is generated by the set E of idempotent endomorphisms of rank n - 1. This thesis gives an alternative proof using a linear algebra and semigroup theory approach. It is also shown that not all the elements of E are needed to generate Sing[sub]n. Necessary conditions for a subset of E to generate found; these conditions are shown to be sufficient if the vector space is defined over a finite field. In this case, the minimum order of all subsets of E that generate Sing[sub]n is found. The problem of determining the number of subsets of E that generate Sing[sub]n and have this minimum order is considered; it is completely solved when the vector space is two-dimensional. From the proof given by Erdős, it could be deduced that any element of Sing[sub]n could be expressed as the product of, at most, 2n elements of E. It is shown here that this bound may be reduced to n, and that this is best possible. It is also shown that, if E+ is the set of all idempotent of Singn, then (E+)n−1 is strictly contained in Sing[sub]n. Finally, it is shown that Erdős's result cannot be extended to the semigroup Sing of continuous singular endomorphisms of a separable Hilbert space. The sub semigroup of Sing generated by the idempotent of Sing is determined and is, clearly, strictly contained in Sing.