The aim of this study was to examine the mechanisms of transcription and replication of the paramyxovirus, simian virus type 5 (SV5). This was initially attempted using reverse genetics techniques and subsequently examining specific viral protein: protein interactions within the replication complex. A cDNA clone encoding a synthetic negative-sense RNA genome analogue was constructed. Reverse genetics techniques were used to attempt to characterise conditions which supported the transcription and replication of this genome analogue, with or without the use of wild-type helper virus but were unsuccessful. During the course of these studies, a number of mammalian cell lines inducibly expressing SV5 proteins were isolated. These cell lines were subsequently used to examine viral protein: protein interactions within the replication complex. When expressed alone, both P and V proteins exhibited diffuse cytoplasmic fluorescence and V was also found in the nucleus. However, when NP was expressed alone, it was seen as punctate and granular cytoplasmic fluorescence. The distribution patterns of the proteins changed when expressed in combination. Large cytoplasmic aggregates similar to those at late times in an SV5 infection were seen in cells which co-expressed NP and P. When NP was co-expressed with V, however, NP was partially redistributed to give diffuse cytoplasmic and nuclear fluorescence. This showed that both P and V proteins could interact with NP and suggested that V may play a role in keeping NP soluble prior to an ordered encapsidation process. Extracts from these cell lines were then used in a novel protein: protein capture assay and demonstrated that NP could interact with both P and V proteins. NP expressed by the cell line was shown to contained both soluble and polymeric forms of NP. P was shown to bind both forms of NP, while V could only bind soluble NP. Since P and V proteins are amino co-terminal, the site of interaction between P and polymeric NP was predicted to be in the P unique C-terminus. This was strengthened when a P-specific C- terminal mAb was found to block the binding of P with polymeric NP. Deletion mutant analysis in the C-terminus of the P protein showed that the mAb binding site was at the extreme C-terminus of the protein suggesting this is the point of interaction between P and polymeric NP. Possible roles for these protein: protein interactions and implications for the paramyxovirus replication complex are discussed.

A brief history of fish biomechanical studies is given and a general introduction on the composition and functional properties of fish muscle, in relation to different swimming activities is presented. Thermal adaptations in teleost fish over both evolutionary and seasonal time scales are discussed at different levels of biological organisation. Chapter 2 The isometric properties of live fast fibres, isolated from the abdominal myotomes of the short-horned sculpin (Myoxocephalus scorpius) were examined at temperatures of 5, 10 and 15°C. The properties of fibres isolated from laboratory-acclimated (5 and 15°C) and naturally-acclimatised, summer (July - September) and winter (January - March) fish were compared to assess the modulating effect of environmental factors other than temperature. Chapter 3 Live fast fibre bundles were isolated from the abdominal myotomes of naturally acclimatised (summer and winter) and laboratory acclimated (5°C and 15°C) sculpin. Force-velocity (P-V) characteristics of the fibres were investigated using iso-velocity releases. The mechanisms behind the acclimatory increases in power output in summer and 15°C-acclimated fish, at 15°C are partly due to increases in the Vmax of the fibres. More importantly force generating capacity shows a major acclimatory adaptation which greatly enhances power output at warm temperatures. Chapter 4 Short-horned sculpin were acclimated to either 5 or 15°C (12 h light: 12 h dark) for 6 - 8 weeks. Prey-capture of Crangon crangon was filmed at 200 frames s-1, using a high speed video. The fish employed the three classic kinematic stages as described by Weihs (1973) in a typical "S" shaped fast start. The kinematics of the fast start were unaffected by temperature or acclimation state. 5°C-acclimated sculpin were tested at 5, 10 and 15°C. Rates of acceleration doubled in the 5°C-acclimated fish between 5 and 15°C. Tail-beat frequency also increased significantly from 5.5 Hz at 5°C to 8 Hz at 15°C. However, mean and maximum velocity and tail-beat amplitude were relatively independent of test temperature. Chapter 5 Fast muscle fibres were isolated from rostral and caudal myotomes of summer-caught, short-horned sculpin. Muscle strain patterns for three positions (0.31L, 0.52L, 0.77L) along the body were calculated from changes in body curvature, during fast-starts at 15°C. Isolated rostral and caudal muscle fibres were subjected to the in vivo strain fluctuations and stimulated with a similar duty cycle (25 - 32%) to that found in vivo. Work loops were generated by plotting force and length. The effect of varying muscle stimulation phase on power output and force generation was investigated. At the anterior position in the body the rostral fibres produced significantly greater force (41.9 kN m-2) compared to the caudal fibres (12.2 kN m-2). Similarly, power output at position 1 was also significantly greater in rostral fibres (28.0 W kg-1) compared to caudal fibres (3.7 W kg-1). No difference was found in the properties of the fibres at positions 2 and 3. This suggests that the rostral fibres have adapted to their local mechanical environment to increase force and power generation, although the mechanisms responsible are unknown. Chapter 6 The major findings of this thesis are discussed relating different aspects of muscle performance to locomotory capabilities of sculpin. Thermal adaptations over the natural environmental temperature range encountered by sculpin are considered and the possible mechanisms involved are discussed. Finally, suggestions for elucidating the molecular mechanisms behind adaptations in the shortening speed and force generation are presented.

Synchronous cultures of a high temperature strain of Chlorella pyrenoidosa have been used to measure the apparent levels of aspartate transcarbamylase and dihydroorotase, the first two enzymes on the pyrimidine nucleotide biosynthetic pathway during the cell cycle of this organism. When the apparent levels of these two enzymes were plotted on a relative increase basis, their rates of increase throughout the cell cycle were different. Dihydroorotase had the greater rate of increase through the first 0.5 of the cycle, whereas aspartate transcarbamylase had the greater rate of increase for the remainder of the cell cycle. These findings tend to support the conclusion that these t:wo enzymes are not coordinately synthesized in Chlorella. A theoretical approach was taken to try to elucidate the mechanisms controlling the rate of RNA accumulation. Of the two enzymes studied, dihydroorotase appears to fulfill the requirements of the enzyme which rate-limits RNA synthesis in this organism. / Master of Science

No description available.

This thesis will deal with certain problems of parametric instabilities in the inhomogeneous plasma. A large amplitude, 'pump' wave can deposit some of its energy into the plasma through resonance with two lower frequency waves (which may be damped). This type of process is a parametric decay of the pump wave and has applications in many fields. We consider, predominantly, that of laser fusion, in which the pump wave is electromagnetic and incident on the plasma. The objective is to deposit as much energy as possible within the plasma. Instabilities reducing this energy input are therefore of importance and it is, mostly, to these that this thesis will turn. They are mostly scattering processes in which one of the decay modes is electromagnetic. We examine the stimulated Brillouin backscattering process (the other decay mode being an ion accoustic wave) from a reference frame in which the plasma is streaming outwards. It is found that, if this velocity is near the sound velocity, the ion acoustic wave has a frequency Doppler-shifted to zero, the electromagnetic waves then having equal frequencies. In such a situation, any reflection of the pump wave at the critical surface will enhance the initial level of the backscattered wave. We find that, allowing for this, there is considerable enhancement of backscatter from the plasma, with consequent energy loss to the pump. Since the effect is noticeably unaffected by 'off- resonance' situations, it is felt that this process could mount a barrier to possible applications. We next consider the stimulated Compton scattering process, where the pump is scattered off the 'bare' or thermal electrons in the plasma. It is found that this rather weak instability occurs predominantly only when electron plasma waves are heavily dampled. Substantial reflection only occurs for high pump powers. Whilst there is little loss to the pump energy, there is substantial perturbation to the background distribution function. However, at the high powers involved filamentation and modulation of the pump can occur with a resulting enhancement of the scattering. Finally, we consider the effect on the decay instability (photon → plasmon + phonon) of the presence of substantial filamentation of the critical surface. It is found that the growth rate is substantially reduced.

The influence of the human facial image was surveyed and the nature of its many interpretations were examined. The role of distinctiveness was considered particularly relevant as it accounted for many of the impressions of character and identity ascribed to individuals. The notion of structural differences with respect to some selective essence of normality is especially important as it allows a wide range of complex facial types to be considered and understood in an objective manner. A software tool was developed which permitted the manipulation of facial images. Quantitative distortions of digital images were examined using perceptual and recognition memory paradigms. Seven experiments investigated the role of distinctiveness in memory for faces using synthesised caricatures. The results showed that caricatures, both photographic and line-drawing, improved recognition speed and accuracy, indicating that both veridical and distinctiveness information are coded for familiar faces in long-term memory. The impact of feature metrics on perceptual estimates of facial age was examined using 'age-caricatured' images and were found to be in relative accordance with the 'intended' computed age. Further modifying the semantics permitted the differences between individual faces to be visualised in terms of facial structure and skin texture patterns. Transformations of identity between two, or more, faces established the necessary matrices which can offer an understanding of facial expression in a categorical manner and the inherent interactions. A procedural extension allowed generation of composite images in which all features are perfectly aligned. Prototypical facial types specified in this manner enabled high-level manipulations to be made of gender and attractiveness; two experiments corroborated previously speculative material and thus gave credence to the prototype model. In summary, psychological assessment of computer-manipulated facial images demonstrated the validity of the objective techniques and highlighted particular parameters which contribute to our perception and recognition of the individual and of underlying facial types.

No description available.

Coxsackievirus B3 (CVB3) is the primary cause of viral myocarditis. The role of cystein-x-cystein (CXC) chemokine ligand 10 (CXCL10, formerly interferon-y-inducible protein 10) in CVB3-induced myocarditis is unknown. To explore the contribution of CXCL10 to CVB3-induced myocarditis, we performed functional analyses using newly generated transgenic mice with cardiac-specific CXCL10 overexpression (Tg) and CXCL10 knock out (KO) mice. The mRNA levels of CXCL10 peaked in the myocardium at day 3 post-infection prior to immune infiltration, suggesting that mainly resident cells of the heart are the sources of CXCL10. Indeed, we showed that CXCL10 can be induced by IFN-y but not by CVB3 infection in cultured cardiomyocytes. Further, a transgenic mouse model with cardiac-specific overexpression of CXCL10 was generated. CXCL10 Tg mice had spontaneous infiltrations of mononuclear cells with limited mRNA upregulation of IFN-y and IL-10, which were not sufficient to cause the impairment of cardiomyocyte or cardiac function. Following CVB3 infection, the viral titre in the mouse hearts inversely correlated with the levels of CXCL10 at day 3 post-infection. Further, the decreased virus titers in the CXCL10 Tg mouse hearts led to reduced cardiac damage indicated by low serum cTnI levels and improved cardiac functional performance and vice versa in the KO mice. This antiviral ability of CXCL10 may be through increased recruitment of natural killer (NK) cells to the heart and increased IFN-y expression early post-infection. At days 7 and day 10 post-infection with massive influx of mononuclear cells, the expression of CXCL10 enhanced the infiltration of CXCR3+ cells, CD4+, and CD8+ T cells as well as their associated inflammatory cytokines. However, the augmented accumulation of these immune cells and associated cytokines did not alter the viral clearance and mouse survival. Our data demonstrate for the first time that CXCL1 0 confers the protection to the heart during the early course of CVB3 infection, which may be primarily attributed to NK cell recruitment to the site of infection. This data suggest that CXCL10 is an important player in the orchestrated action of a group of cytokines and chemokines in combating against the CVB3-induced myocarditis in the early phase of infection.

This thesis is a report of acoustical research on the concert harp. The harp has an established place in the symphony orchestra and is reacquiring its role as a solo chamber instrument that it had before the development of the modern piano. As far as can be determined, this is the first doctoral thesis on the concert harp and serves as an introduction to the science of the instrument, The experimental methods employed- holographic interferonietry, input admittance measurements, Chiadni glitter pattern methods, sound pressure level measurements- have all been successfully used with work on other musical instruments. Theoretical calculations are used to underpin the experimental results for several of the subjects reported. The experimental results are also compared with the results of similar tests on different musical instruments. Analyses of the violin, guitar and piano are particularly used in discussions. This work is specifically on the "Orchestra" concert harp, manufactured and sold by the Salvi Harp organisation, though reference Is made in Chapter 3 to the "Electra" concert harp, which is also a Salvi harp. The "Orchestra" harp has a similar design to many other concert harps built by different luthiers around the world. This thesis is structured as follows. The first chapter is a review of historical and contemporary research an stringed musical instruments. The next chapter is a detailed description of the Salvi "Orchestra" harps the dimensions of all the inportant features are given, the tensions and materials of the strings are reported and there is also a short description on the playing of the instrument. The next five chapters form the kernal of the research report and deal with the vibrations of the constituent part of the "Orchestra" and finally the completed, strung harp itself. In Chapter 3, the vibrations of the free soundboard are reported in some detail. Analysis is made at a number of stages of the construction of the soundboard itself. The position of the neutral axis on the soundboard is also given. There is also reference to the soundboard of the Salvi "Electra" harp. Chapter 4 deals with the air resonances in the enclosed air volume of the "Orchestra" soundbox. Both a Helmholtzian air mode and higher order air modes are discussed. Theoretical models are used for both forms of air modes, Chapter 5 is a report of the vibrational modes of the "Orchestra" soundbox using both Chladni glitter patterns and holographic interferonietry. The results of Chapter 5 are confirmed and expanded by the work in Chapter 6, where input admittance measurements are made on the soundbox.Chapter 7 investigates the vibrational modes of the soundbox, both in the isolated state and as part of a completed, strung harp. This is followed by a chapter on the directivity of the "Orchestra" harp in which the principal areas of radiation from the harp are reported. The next chapter deals with attempts to relate objective measurements with subjective opinions of six concert harps. The last chapter summarises the principal results of the various analyses reported in this thesis. Suggestions for further research on the harp are made. There are also suggestions for the improvement of the Salvi "Orchestra" harp. There are three appendices at the end of this work. The first deals with the testing of spruce samples intended for the soundboards of the harps. The effect of the veneer is also discussed. The second appendix deals with the production and physical properties of gut harp strings. The third appendix describes the changes to the resonant modes of an isolated soundbox produced by changing the shape of the straining and cover bars of the soundboard.

Coxsackievirus B3 (CVB3) is the primary cause of viral myocarditis. The role of cystein-x-cystein (CXC) chemokine ligand 10 (CXCL10, formerly interferon-y-inducible protein 10) in CVB3-induced myocarditis is unknown. To explore the contribution of CXCL10 to CVB3-induced myocarditis, we performed functional analyses using newly generated transgenic mice with cardiac-specific CXCL10 overexpression (Tg) and CXCL10 knock out (KO) mice. The mRNA levels of CXCL10 peaked in the myocardium at day 3 post-infection prior to immune infiltration, suggesting that mainly resident cells of the heart are the sources of CXCL10. Indeed, we showed that CXCL10 can be induced by IFN-y but not by CVB3 infection in cultured cardiomyocytes. Further, a transgenic mouse model with cardiac-specific overexpression of CXCL10 was generated. CXCL10 Tg mice had spontaneous infiltrations of mononuclear cells with limited mRNA upregulation of IFN-y and IL-10, which were not sufficient to cause the impairment of cardiomyocyte or cardiac function. Following CVB3 infection, the viral titre in the mouse hearts inversely correlated with the levels of CXCL10 at day 3 post-infection. Further, the decreased virus titers in the CXCL10 Tg mouse hearts led to reduced cardiac damage indicated by low serum cTnI levels and improved cardiac functional performance and vice versa in the KO mice. This antiviral ability of CXCL10 may be through increased recruitment of natural killer (NK) cells to the heart and increased IFN-y expression early post-infection. At days 7 and day 10 post-infection with massive influx of mononuclear cells, the expression of CXCL10 enhanced the infiltration of CXCR3+ cells, CD4+, and CD8+ T cells as well as their associated inflammatory cytokines. However, the augmented accumulation of these immune cells and associated cytokines did not alter the viral clearance and mouse survival. Our data demonstrate for the first time that CXCL1 0 confers the protection to the heart during the early course of CVB3 infection, which may be primarily attributed to NK cell recruitment to the site of infection. This data suggest that CXCL10 is an important player in the orchestrated action of a group of cytokines and chemokines in combating against the CVB3-induced myocarditis in the early phase of infection.