The feasibility of sports grips customisation using rapid manufacturing methodologies

In many sports where an implement is used to strike a ball, the grip is typically the sole point of contact between the player and implement. The grip significantly influences how a player wields an implement and is also a means for a player to experience impact forces and vibration. This transmission of force and vibration to the hand can affect a player's control, perception of the equipment, and also expose a player to injury or provoke degeneration of existing maladies. In general, the grip is the least expensive component of an implement. Little development over the previous two decades has been invested on the grip when compared to the vast changes in design, geometry and materials used in the implements which they are attached to. The development and flexibility of a group of manufacturing processes collectively known as rapid manufacturing have begun to introduce customised products to the mass-market. The main advantage of rapid manufacturing processes is the lack of tooling required, allowing parts to be produced directly from 3D CAD models using an expanding range of polymers and other materials. The integration of rapid manufactured parts into recreational sports equipment has not previously been attempted and is the focus of this work, with tennis selected as the candidate sport. [Continues.

Investigations of RNA production and processing in Saccharomyces cerevisiae

Over the course of 10 years and 14 publications, 7 of which are described in this thesis, I made significant contributions to the field of RNA processing, particularly RNA splicing in budding yeast. These contributions have been both in knowledge accrued and techniques developed and optimised. For the Ribo1 reporter (chapter 2), I developed the RT-qPCR assays, RNA copy number/cell estimation and 3’ end cleavage assay. These show that the minimum time taken for signal induction, recruitment, assembly of transcription factors and ultimately transcription, is in the order of 4 minutes, with transcription rates of 60 to 90 seconds per kb. The 3’ end cleavage assay reveals that the initial pulse of transcripts may be spliced only partially co-transcriptionally; presumably splicing factors are recruited to the site of transcription during this period. After this initial phase, in the reporter at least, splicing is almost exclusively co-transcriptional. Mutant transcripts on which spliceosomes assemble but are unable to complete splicing, are targeted for very rapid degradation. I have optimised the thio-labelling technique to the point where I can detect thiolated RNAs just 15 seconds after addition of the 4-thiouracil nucleotide analogue to cell cultures (chapter 3). From my data and transcriptome sequencing (chapter 4), I have constructed models of transcription and splicing, which indicate that co-transcriptional splicing is a general feature of most yeast pre-mRNA transcripts and almost all ribosomal protein gene transcripts. Intronic features that act against co-transcriptional splicing include runs of uracils and secondary structure, especially over the branch point adenosine (chapter 4). I have provided a highly detailed protocol and video for thio-labelling of RNA in vivo and its purification (chapter 3). Similarly, I have developed and prepared a comprehensive protocol for auxin-induced protein depletion, to the point where this is the most flexible and least metabolically perturbing technique for doing this in yeast (chapter 6). Applying this method, whilst thio-labelling, I revealed that depleting splicing factors sequesters spliceosome components, rapidly resulting in the cessation of splicing (chapter 7). My microarray results indicate that this is a common consequence of splicing factor deactivation for many or all transcripts. In this thesis I examine RNA metabolism, noting that the processes of transcription, splicing, 3’ end formation and degradation are coordinated and harmonised to optimise fidelity, flexibility and efficiency

Interaction of yeast eIF4G with spliceosome components Implications in pre-mRNA processing events

International audienceAs evidenced from mammalian cells the eukaryotic translation initiation factor eIF4G has a putative role in nuclear RNA metabolism. Here we investigate whether this role is conserved in the yeast Saccharomyces cerevisiae. Using a combination of in vitro and in vivo methods, we show that, similar to mammalian eIF4G, yeast eIF4G homologues, Tif4631p and Tif4632p, are present both in the nucleus and the cytoplasm. We show that both eIF4G proteins interact efficiently in vitro with UsnRNP components of the splicing machinery. More specifically, Tif4631p and Tif4632p interact efficiently with U1 snRNA in vitro. In addition, Tif4631p and Tif4632p associate with protein components of the splicing machinery, namely Snu71p and Prp11p. To further delineate these interactions, we map the regions of Tif4631p and Tif4632p that are important for the interaction with Prp11p and Snu71p and we show that addition of these regions to splicing reactions in vitro has a dominant inhibitory effect. The observed interactions implicate eIF4G in aspects of pre-mRNA processing. In support of this hypothesis, deletion of one of the eIF4G isoforms results in accumulation of un-spliced precursors for a number of endogenous genes, in vivo. In conclusion these observations are suggestive of the involvement of yeast eIF4G in pre-mRNA metabolism

Mathematical modelling of pulsatility in neuroendocrine systems.

The work described in this thesis concerns the mathematical description of the characteristic oscillatory electrical behaviour of certain neurosecretory cells found in the hypothalamus of the mammalian brain. This study concentrates on those cells which secrete the hormone oxytocin. A model first described by Hodgkin and Huxley is used as a starting point for the derivation of a description comprising a system of coupled non-linear partial differential equations. The equations have been based wherever possible on experimental data relevant to the system being studied. Where this has not been possible, alternative models based on data from other, related systems have been used. The thesis starts with a discussion of the physiology of the system under study and presents some background material. The second chapter discusses the process of mathematical modelling of neurones and presents some of the relevant work in the area. The model due to Hodgkin and Huxley is significant and is discussed in detail. The research methodology is then outlined. Experimental procedures for recording the electrical behaviour of nerve cells and methods of recording selected ionic currents are the subject of chapter three. Chapter four presents a discussion of oscillatory behaviour in nerve cells at a general level and outlines the features necessary for a nerve cell to exhibit oscillation. The next three chapters discuss the characteristics of the different ionic currents involved and describe the author's derivation of models of these currents. Chapter Five presents the author's model of the sodium current, Chapter Six, the potassium currents and Chapter Seven, the calcium current. The experimental work undertaken and the results obtained are then presented and discussed.During the course of this study a number of computer programs were written and tested by the author. The program listings appear in the appendix. The thesis is significant and contributes to the body of knowledge in that no other mathematical model of the unique bursting behaviour of oxytocin-secreting cells exists as far as the author is aware

Microarray detection of novel nuclear RNA substrates for the exosome

Microarray analyses were performed on yeast strains mutant for the nuclear-specific exosome components Rrp6p and Rrp47p/Lrp1p or the core component Rrp41p/Ski6p, at permissive temperature and following transfer to 37 degrees C. 339 mRNAs showed clearly altered expression levels, with an unexpectedly high degree of heterogeneity in the different exosome mutants. In contrast, no clear alterations were seen in strains lacking the cytoplasmic exosome component Ski7p. 27 mRNAs that were overexpressed in each strain defective in the nuclear exosome are good candidates for regulation by nuclear turnover. These included the mRNA for the autoregulated RNA-binding protein Nrd1p. Northern and primer extension analyses confirmed the elevated NRD1 mRNA levels in exosome mutants, and revealed the accumulation of truncated 5' fragments of the mRNA. These contain a predicted Nrd1p-binding site, potentially sequestering the protein and disrupting its autoregulation. Several genes located immediately downstream of independently transcribed snoRNA genes were overexpressed in exosome mutants, presumably due to stabilization of the products of transcription termination read-through. Further analyses indicated that many snoRNA and snRNA genes are inefficiently terminated, but read-through transcripts into downstream ORFs are normally rapidly degraded by the exosome. Copyright (c) 2006 John Wiley & Sons, Ltd

Sensorless Control of im for Limp-Home Mode EV Applications

This paper presents a novel speed estimation scheme for induction motors (IMs) based on back electromotive-force model reference adaptive system (back-EMF MRAS). The scheme is employed for the purpose of sensorless fault-Tolerant torque-controlled drives used in a limp-home mode operation in electric vehicle (EV) applications. The proposed scheme was experimentally tested on a laboratory dynamometer using a 19-kW IM and a 29-kW controller, which are both currently used in the automotive industry for EV applications. The scheme was also implemented on an electric golf buggy which was equipped with a 5-kW IM. A performance comparison was carried out between the proposed and conventional back-EMF MRAS schemes for starting from standstill, sensitivity to parameter variations and constant speed operation with load variations. Utilizing the golf buggy, the behaviors of the new scheme was separately investigated for vehicle starting from standstill, wide speed range including field weakening region, and hill-starting operations. The proposed scheme is computationally easy to implement, robust against sensitivity to parameters variations, inverter nonlinearity and errors due to digitization in the field weakening region. This scheme is not only consistent for vehicle starting from standstill, it also provides a reliable vehicle-drive in the field weakening region and during vehicle hill-starting. The dynamometer and vehicle test-drive results show the suitability of the proposed scheme for the purpose of EV fault-Tolerant limp-home mode operation

The use of structured relationship modelling techniques as a tool to elicit customizable product features

The current article discusses a procedure for the elicitation of product requirements from a target group of users. The use of the method to help develop products with customizable elements is evaluated as this is one area in which this procedure is considered effective. The technique of forming a structured relationship model uses open-ended questions to elicit subject’s sensations when using the product under investigation. Inductive content analysis is then performed on the responses to allow a structured relationship model to be developed

The visual and beyond : characterizing experiences with auditory, haptic and visual data representations

Research in sonification and physicalization have expanded data representation techniques to include senses beyond the visual. Yet, little is known of how people interpret and make sense of haptic and sonic compared to visual representations. We have conducted two phenomenologically oriented comparative studies (applying the Repertory Grid and the Microphenomenological interview technique) to gather in-depth accounts of people's interpretation and experience of different representational modalities that included auditory, haptic and visual variations . Our findings show a rich characterization of these different representational modalities: our visually oriented representations engage through their familiarity, accuracy and easy interpretation, while our representations that stimulated auditory and haptic interpretation were experienced as more ambiguous, yet stimulated an engaging interpretation of data that involved the whole body. We describe and discuss in detail participants' processes of making sense and generating meaning using the modalities' unique characteristics, individually and as a group. Our research informs future research in the area of multimodal data representations from both a design and methodological perspective.Postprin