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School counselors have been encouraged to operate within a multi-tiered system of support and develop a comprehensive school counseling program to oversee the academic, social emotional, and career development of their students (Goodman-Scott & Ockerman, 2019). To guide their program, school counselors may choose to utilize the American School Counselor Association Student Standards: Mindsets and Behaviors (American School Counselor Association, 2021). This study seeks to contribute to the research on the Mindsets and Behaviors by evaluating the effectiveness of the True Goals School Counseling Curriculum as a Tier 1 intervention for junior high students according to specific standards of the Mindsets and Behaviors as they relate to two valuable student assets: hope and sense of school belonging. Structural equation modeling was used to evaluate the impact of the intervention. Results indicated that students who received the True Goals School Counseling Curriculum had nonsignificant increases in their hope and sense of school belonging. However, the mediation analysis indicated a significant relationship between their hope and sense of school belonging. Implications for school counseling, counselor education, and social justice are discussed, and the researcher offers suggestions for future research. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

Knowing how teachers plan the curriculum for pupils is essential to understanding how they view the nature and purpose of education in the contexts that they find themselves. With the development of the academies programme and Free Schools, where teachers are encouraged to be creators of curriculum, this task has never been more urgent. This study took five secondary teachers of religious education (RE) in English schools and looked at how they planned their subject for pupils in Years 7 and 8, with a focus on the latter. Using repertoires of action research the study looks at the underlying educational beliefs of teachers, their own personal histories and context of their school to produce comparative case studies. The comparison of case studies identified common themes and significant difference of approach set against the expectation that might be had of those teachers who were trained RE teachers and those who were not. Three of the schools in this study were non-denominational schools and two Church of England secondary schools, allowing a comparison of teachers in shared and different contexts. The approach taken in the research is embedded in the Critical Realist tradition and it looks to discover the underlying cultural structures that have an impact on teachers internalised worldviews. It explores how understanding cultural structure can better enable researchers to see its impact on real decisions made by teachers.

This thesis is concerned with the design development of cold-formed steel portal frames at both ambient and elevated temperatures. A full-scale site test was carried out to determine the behaviour in fire, of a portal frame structure comprised entirely from cold-formed steel. Laboratory component tests were used to investigate joint behaviour at ambient temperature. Numerical modelling was used to extend the investigations without the need for further physical testing. Good agreement between the experimental tests and non-linear finite element (NLFEA) models was obtained. The finite element models were then used in an extended study, the purpose of which was to develop the basis for a performance based design approach. At ambient temperature, the inclusion of joint stiffness in models was demonstrated as important in order to accurately predict the behaviour of frames. Design recommendations are proposed that are based on both the experimental and finite element results. At elevated temperature, the importance of base fixity and in-plane restraint from side-rails was highlighted as being crucial in preventing undesirable outwards collapse. Design recommendations in the form of a mathematical model, protection advice and construction details are proposed, that are based on both the experimental and finite element results. In the absence of published design recommendations, the guidance and NLFEA shell model presented can be used by practicing engineers to assist in design of cold-formed steel portal frames in fire boundary conditions.

The aims and objectives of this study are to examine the role of mouthguards and the materials that are used for their manufacture, the heating process they undergo during manufacture and how the lamination of different materials into a multi-layered system to form a composite structure may affect the impact absorbing capabilities. The effect of heat on pEVA during the manufacturing process was investigated using an instrumented dropweight impact testing rig and a polariscope to observe internal stress as it was felt that the physical properties of the material could be adversely affected by this part of the process. Laminated structures, using several different materials, (pEVA, PMMA, silicone rubber, synthetic wax, modelling clay, soft denture lining material and a semi-solid synthetic rubber) were tested as it was felt that the lamination of different materials with a range of physical properties would exhibit less deformation and transmit less of the impact energy. To ascertain how a mouthguard may react during an impact event by simulation tests in the impact test rig. Methods: For the heat treatment of pEVA a furnace was used to heat the test material to near its' glass transition temperature (Tg) of 84'C ±3 'C. The material was brought up to Tg and held at that point for 10 minutes. The specimens were then removed from the furnace and allowed to cool to room temperature. Heat treated and non-heat treated samples were placed in a polariscope to observe stress within the material. Dropweight impact tests were conducted on all samples using an instrumented impact testing rig. All samples were circularly clamped and force-time and displacement-time plots obtained. The samples were placed again in the polariscope and any changes in stress were noted. To observe the processing effects of the manufacturing procedure five mouthguards were made on the same cast and were brought to various stages of completion. Different 'lay-ups' of pEVA along with laminations and sandwiches of pEVA, PMMA, silicone rubber, synthetic wax, modelling clay, semi-solid synthetic rubber and denture soft lining were also tested using the dropweight impact tester. For the impact simulation tests samples of 50mm. diameter were placed on top of a PMMA substrate, that was clamped in the impact rig, to see how the test sample would protect the substrate during impact. Results: The Peak Impact Force (PIF) of heat treated pEVA was lower (PIF<140N) than that of untreated pEVA (PIF=160N). The displacement of the heat treated sample during impact increased by 66%, (untreated pEVA>18mm centre displacement, heat treated pEVA >30mm centre displacement). Digital photographic images from the polariscope show that the heat treatment of pEVA virtually eliminates stress and following impact the amount of stress, seen photoelastically, was also reduced. Images of material in the polariscope also indicate that the finishing techniques employed during the manufacturing process have a direct effect on the stress distribution within the mouthguard. A 5mm laminated structure of pEVA, PMMA and silicone rubber was able to absorb more impact energy (PIF = 275N) and exhibited less deformation (1.4mm) than that of a monolithic structure of 5mrn heat treated pEVA (PIF <140N, displacement >30mm). Simulation tests showed that the 5mm. thick pEVA protected the PMMA better (PIF = 325, displacement 6.8mm) than the Imm pEVA (PIF = 340, displacement 7.7mm). Conclusions: The mouthguard forming process has a direct effect on the internal stresses of pEVA and therefore its physical response. When pEVA is laminated with PMMA and silicone rubber the impact absorbing capabilities are better than a monolithic structure of pEVA. Mouthguards for use in contact sports, therefore, should incorporate a laminated section of pEVA, PMMA and silicone rubber. Simulation tests show that 5mm thick samples protect a substrate more effectively than I- 4mm test samples.

We introduce the braid groups in their connection to knot theory and investigate several of their properties. Based on term rewriting systems, which we review, we find new solutions to the word and conjugacy problems in the braid groups. A similar problem asks for the minimal length word for an equivalence class in a given braid group which we prove to be NP-complete (after a review of this concept) and present a new algorithm for it. As this algorithm takes an exponentially increasing amount of time, we construct an algebraic approximation algorithm which we find to work well. We consider several methods of approximating the minimal word via computer simulation of the braid strings moving under the influence of certain forces. Using the theory of tangles which we also review, we construct a new notation for knots which is usable by a computer. From this notation, we construct an efficient algorithm to find the braid or plat whose closure is ambient isotopic to any given knot. Finally, we apply the computer software developed for these problems to the solar coronal heating problem by simulating magnetic flux tubes. We also present a number of incidental results that were found along the way of researching these problems.

It has been widely recognised in the computational intelligence and machine learning communities that the key to understanding the behaviour of learning algorithms is to understand what representation is employed to capture and manipulate knowledge acquired during the learning process. However, traditional evolutionary algorithms have tended to employ a fixed representation space (binary strings), in order to allow the use of standardised genetic operators. This approach leads to complications for many problem domains, as it forces a somewhat artificial mapping between the problem variables and the canonical binary representation, especially when there are dependencies between problem variables (e.g. problems naturally defined over permutations). This often obscures the relationship between genetic structure and problem features, making it difficult to understand the actions of the standard genetic operators with reference to problem-specific structures. This thesis instead advocates making the representation of solutions of the explicit focus, in order to highlight the way in which the genetic operators (and resulting search algorithms) form and test hypotheses about the relationship between observed problem structure and films. It is clear that any search algorithm must limit the class of hypotheses which it is able to learn (its bias), if it is to select the most accurate of those hypotheses efficiently. We demonstrate this in the context of evolutionary search by exploring the so-called "no free lunch" results, and argue that it is the chosen representation which determines what kinds of hypotheses can be formed and tested by the algorithm. To do this, we exploit a general formalism for generating a representation for an arbitrary instance of a given problem domain, using a characterisation of that problem domain which captures beliefs about its structure. Such a characterisation is simply an explicit set of mathematical statements about the relationship between features of solutions and their fitness values, making it clear that the resulting representations encapsulate all of the domain knowledge which is available to any search algorithm.

Preliminary experiments employing the Mudlux reporter system indicated that the ahp locus was osmotically sensitive in S. typhimurium. Studies on other bacteria supported this view. The affect of the osmotic environment of the cell upon the expression of ahp was therefore addressed in greater depth. The subsequent use of immunoblotting techniques conclusively demonstrated that chromosomal expression of the ahp locus was not affected by the osmotic environment surrounding the cell. Instead, the Mudlux element was found to alter the natural behaviour of the ahp promoter in such a way that it adopted an osmotically-regulated status, and this mode of regulation appeared to override regulation via the normal hydrogen peroxide-inducible mechanism. S. enterica is an intracellular pathogen which is capable of surviving within macrophage cells. Macrophages are equipped with an arsenal of anti-microbial effector mechanisms, including a respiratory burst which generates reactive oxygen metabolites. Since ahp had previously been shown to respond to the respiratory burst of macrophages, this study also assessed the role of oxidative stress resistance genes in the virulence of S. typhimurium. Strains of the mouse pathogen Sl1344 were constructed in which the ahp and oxyR loci were disrupted and their virulence was assessed in LD₅₀ studies. Disruption of the ahp or oxyR loci was found to have no effect upon the gross virulence of SL1344 for mice, suggesting that these loci were not essential for survival within the macrophage. The ability to develop immunity against infection by S. typhimurium is thought to correlate with the development of immunity against bacterial antigens which are expressed in vivo. As a further part to this study, the immunological responses of mice to two S. typhimurium-derived polypeptides, AhpC and GroEL, following cloning and overexpression of these proteins, were examined. Mice previously infected with an attenuated strain of S. typhimurium were shown to elicit significant delayed-type hypersensitivity reactions following subcutaneous injection of these polypeptides 33 and 104 days post-infection. Moreover, AhpC-and GroEL-specific antibodies were detected during the course of infection of mice with S. typhimurium.

This thesis is concerned to discover the nature of regional identity in Furness and Cartmel, also known as Lancashire North of the Sands, in the 50 years around 1800, and explore the relationship between the essential regional qualities, geographical and cultural, of the area, and the way it was viewed by the human inhabitants. The methodology is heavily biased towards a thorough survey of surviving archival material in the county record offices and public libraries of Cumbria, Lancashire and Cheshire and the integrating of these sources into a coherent narrative of the period, which is then analysed. Attempts have been made to quantify wherever possible, but the sophistication of the statistical manipulation is kept in proportion to the reliability of the gathered data. Chapter 1 surveys the ways in which regions within England have been defined and the uses to which a regional approach can be put. Chapter 2 provides an introductory overview of the society of the area, concentrating on the degree of population mobility. Chapter 3 examines the development of various economic sectors in the period, and the way in which those sectors were spatially organised, both as a result of natural topography and under the influence of human actors. Chapter 4 studies the way in which the manorial administrative system of the area was replaced by a more rationalised system mediated by lawyers, and the influence of statutes and enclosure on this process. Chapter 5 is concerned with the degree of local distinctiveness from national patterns in the administration of the Poor Law, and in the way the authorities reacted to the problems of crime and popular politics. Chapter 6 looks at the factors affecting religious observance, and the reference of both Anglican and dissenting churches to authorities from without the area. Chapter 7 inquires into the ways in which patterns in education, recreation and sexual practices mark either the exclusivity of the area or its absorption into national trends. Chapter 8 concludes that although the area had many distinct regional characteristics, both of ecotype and of culture, and although these are important in explaining many aspects of development in this period, the most distinctive quality of the area was the way in which it lent itself to reinvention by individual human actors, particularly outside colonisers. The originality of the thesis lies in its genuinely integrated study of an area of town and country, and its application of extra-disciplinary ideas (particularly the distinctions between essence and imagination, and material and information) to an English local study of this period.

There has been much debate regarding the impact of state-mandated assessment in schools. Most of the literature on this topic has been gathered from studies focused on teachers' perceptions (Hungerford, 2004). The effects, typically perceived to be negative, indicate reduced quality of teaching and learning in schools. The purpose of this study was to investigate elementary school principals' perceptions of the impact of the Massachusetts Comprehensive Assessment System (MCAS) testing culture on the six conditions for effective learning (Tyler, 1992) within their schools. A sequential explanatory mixed-methods approach was used. A total of 225 principals in Massachusetts responded to the "Principal Perception Survey." Qualitative data were then gathered from 15 of these respondents through telephone interviews guided by the "Principal Perception Interview" protocol. Examination of the data gathered led to the following conclusions: *Principals perceive the MCAS testing culture has had a positive impact on all six of the conditions for effective learning. Findings suggest that feedback and purpose are most positively impacted. *Principals value the momentum established in creating a "data culture" within schools. They feel this is a direct result of the sense of urgency felt by all staff to consistently monitor student progress and use data gathered to make informed decisions about how to teach individual students. *Principals believe MCAS testing has been critical to the emphasis that school districts have placed upon implementation of the Massachusetts Curriculum Frameworks. They feel this has led to greater clarity of purpose at the classroom level, as well as to greater consistency throughout the Commonwealth. *Principals have many concerns about MCAS testing and its impact on their schools. Qualitative findings revealed that principals were far more positive when talking about the impact of the MCAS testing culture than they were when talking about specific shortcomings of MCAS testing. Up to this point, the perceptions of elementary principals pertaining to state-mandated testing systems have been underrepresented in the literature. With major changes being discussed and formulated at the national level pertaining to mandated assessments in schools, the perspective added by school leaders within this study should be of great value. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

A theory is presented according to which language users hold to employ detailed videotape-like memory traces of prototype objects in association with their lexemes for the purpose of mediating the application of lexemes. The theory is advanced by pointing to flaws in rival conceptions, which are for this purpose amalgamated under the label "theory of criterial attributes". In an extensive discussion of psychological issues the theory of prototypes is shown to be plausible in terms of what is known of human mental structures and operations. A longitudinal study (up to the age of years) of concrete nominals in the vocabularies of three young children is also offered in support of this view. The following properties of the children's words and usage are noted: accuracy, diversity within denotation classes (inclining the dispensability of even functional and contextual factors which at other times appear to be crucial in the application of the same word), vacillation in the selection of a name for an object and caution in extending denotation classes. The children's lexical structures are also examined.

Today Americans have little knowledge or understanding of the migration of Americans into the West during the 1840’s and 1850’s. In particular, Americans are not aware of the contribution that women made to the development of the American West during this period. For a woman, migrating to, and settling in, the West was a frightening and exhausting ordeal; but an ordeal over which they prevailed, decisively. The objective of this thesis is to bring about a better understanding of the women who journeyed to the West; what they endured during the journey, and the contribution they made to the development of a civilized American society at their destinations. For purposes of achieving this thesis’ objective we will examine women’s experiences before, during and after what is known as the Oregon Trail; a two thousand one-hundred-mile journey, undertaken during the 1840’s and 1850’s, across absolute wilderness, from points on the Missouri River to the Willamette River Valley, in the Oregon Territory. This thesis is focused upon the Oregon Trail, in particular, because it was undertaken not for the purpose of religious separation such as the Mormon’s journey to Salt Lake, nor was it undertaken for the mining of gold as was the case for much of the travel to California during this period, nor was it undertaken for the purpose of trade as was the case for what was known as the Santa Fe Trail. Rather, the Oregon Trail was undertaken primarily to travel from one homestead in order to create another homestead: a homestead requiring the presence of a family; a husband, and a wife, and children, all prepared to make their respective contributions to the success of the enterprise. With the Oregon Trail we have a ‘clearer slide’ for our analytical microscope. This thesis examines scholarly work on the subject as well as individual diaries, journals and letters written by women who travelled the Oregon Trail. In getting to Oregon between 1840 and 1860, and in creating successful homesteads, businesses, political structures, and an encompassing, supportive society, women made an effort and contribution that should be better appreciated by Americans. Professor John M. Faragher wrote in the introduction to his book Women and Men on the Overland Trail, “Still, despite the thousands of pages in print [of diaries, journals, letters by travelers], interesting scholarly interpretations of the Overland Trail experience are a relatively rare commodity and there is ample room for new scholarship.”

School counselors have been encouraged to operate within a multi-tiered system of support and develop a comprehensive school counseling program to oversee the academic, social emotional, and career development of their students (Goodman-Scott & Ockerman, 2019). To guide their program, school counselors may choose to utilize the American School Counselor Association Student Standards: Mindsets and Behaviors (American School Counselor Association, 2021). This study seeks to contribute to the research on the Mindsets and Behaviors by evaluating the effectiveness of the True Goals School Counseling Curriculum as a Tier 1 intervention for junior high students according to specific standards of the Mindsets and Behaviors as they relate to two valuable student assets: hope and sense of school belonging. Structural equation modeling was used to evaluate the impact of the intervention. Results indicated that students who received the True Goals School Counseling Curriculum had nonsignificant increases in their hope and sense of school belonging. However, the mediation analysis indicated a significant relationship between their hope and sense of school belonging. Implications for school counseling, counselor education, and social justice are discussed, and the researcher offers suggestions for future research.

Recent advances in genome engineering technologies based on the CRISPR-associated RNA-guided endonuclease Cas9 are enabling the systematic interrogation of genome function. Analogous to the search function in modern word processors, Cas9 can be guided to specific locations within complex genomes by a short RNA search string. Using this system, DNA sequences within the endogenous genome and their functional outputs are now easily edited or modulated in virtually any organism of choice. Cas9-mediated genetic perturbation is simple and scalable, empowering researchers to elucidate the functional organization of the genome at the systems level and establish causal linkages between genetic variations and biological phenotypes. To facilitate successful and specific Cas9 targeting, we first optimize the guide RNAs (sgRNA) to significantly enhance gene editing efficiency and consistency. We also systematically characterize Cas9 targeting specificity in human cells to inform the selection of target sites and avoid off-target mutagenesis. We find that SpCas9 tolerates mismatches between guide RNA and target DNA at different positions in a sequence-dependent manner, sensitive to the number, position and distribution of mismatches. We also show that Cas9-mediated cleavage is unaffected by DNA methylation and that the dosage of Cas9 and sgRNA can be titrated to minimize off-target modification. Additionally, we provide a web-based software tool to guide the selection and validation of target sequences as well as off-target analyses. We next demonstrate that Cas9 nickase mutants can be used with paired guide RNAs to introduce targeted double-strand breaks. Because individual nicks in the genome are repaired with high fidelity, simultaneous nicking via appropriately offset guide RNAs can reduce off-target activity by over 1,500-fold in human cells. In collaboration with researchers at the University of Tokyo, we further identified a PAM-interacting domain of the Cas9 nuclease that dictates Cas9 target recognition specificity. Finally, we present protocols that provide experimentally derived guidelines for the selection of target sites, evaluation of cleavage efficiency and analysis of off-target activity. Beginning with target design, gene modifications can be achieved within as little as 1-2 weeks. Taken together, this work enables a variety of genome engineering applications from basic biology to biotechnology and medicine.

The tenuous boundaries that separate humans, animals, and machines fascinate and sometimes unsettle us. In eighteenth-century France, conceptions of what differentiates humans from animals and machines became a sustained topic of interest in spaces that were public and private, recreational and intellectual. This dissertation argues that eighteenth-century harpsichords were porous sites where performers, composers, artisans, academics, and pedagogues negotiated the limits of these fragile boundaries. French harpsichords are at the center of my dissertation because they embodied an experimental collision of animal parts and other biomatter, complex machinery, and visual and musical performance. Taken together, I consider the ways that instruments had social import apart from sound production alone, expanding the definition of “instrument” beyond traditional organological studies of style in craftsmanship and musical aesthetics.I use an “entangled organology” that traces economic, technological, scientific, and environmental convergences to reveal the thick networks through which harpsichords traveled and the behavioral codes and motivations that instrument makers, performers, listeners, composers, and philosophers embedded into them. I follow the 1687 French embassy to Siam to show how harpsichords were crucial in intercultural, diplomatic exchanges as gifts, bribes, or as sources of teachable knowledge. I examine Jacques de Vaucanson’s 1738 flute-playing android to show how musical instruments mobilized debates in human anatomy and the mechanical arts. I then focus on bird and monkey genre paintings (singerie) on harpsichords’ surfaces to show how harpsichords evoked the contested human-animal divide. Next, I use Jean-Philippe Rameau’s harpsichord manual of 1724 and songbird pi�ce to narrate musical confrontations with nature between player and machine. Finally, I bring together early modern brain and nerve theories and an analysis of a pair of keyboard rondeaux by Joseph-Nicolas-Pancrace Royer to demonstrate how harpsichord music embraced neurocultural findings on the exceptionalism of human cognition over animals and machines. Drawing from historically informed performance practices, the history of the book, the history of science and technology, art history, and material culture, “Wond’rous Machines” questions implicit assumptions about music, music making, and the fixity of musical instruments to argue that there are kinds of musical engagements, or musicking, that conventional organologies cannot explain.

The rational development of drugs against diseases such as infections, immunological disorders, cancer, inflammation etc. requires a detailed understanding of the proteins involved in these diseases. This work aims to provide novel insights into such proteins, their structural and dynamic behavior, their modifications and their interactions with small molecules or other proteins to maximize the potential to combat diseases caused by these proteins using rational drug design. This PhD project is subdivided into six projects, each of which focuses on a different protein involved in diseases which has been difficult to interfere with due to a variety of challenging aspects. Project 1 is focused on the bacterial membrane-bound enzyme MraY. Studies on the inhibition of different MraY isoforms in divergent purification systems with muraymycins and muraymycin analogues provided insights into the influence that the experimental conditions have on the investigation of MraY inhibition. Furthermore, the possibility of resistance development through single-point mutations was shown and analyzed. Additionally, a protein-protein interaction between MraY and the soluble enzyme MurF was proven and foundations were laid to understand the structural and biological implications of this interaction. Project 2 revolved around the intrinsically disordered N-terminal and regulatory domains of NFAT. Novel NMR experiments were developed that will improve the analysis of IDPs and the mechanism of subcellular localization of NFAT by phosphorylation was deciphered. Protein dynamics influenced by phosphorylation were analyzed and a basis to solve the structural ensemble of NFAT’s transactivation domain was provided. In addition, a mechanism to control a protein’s function by introduction of binding motifs into IDRs was provided. Project 3 furnished new avenues to target the master regulator for eukaryotic protein translation eIF4E for cancer treatment. An inhibitor targeting a novel cavity was developed and cell-permeable degraders were generated. Also, the structural and functional implications of eIF4E phosphorylation were highlighted by solving the structure of phosphorylated eIF4E. Project 4 aimed to elucidate the specificity in substrate recognition by AHL-synthases of acyl carrier proteins loaded with different cargoes. In project 5, the oligomeric nature of GILZ was shown and experiments were conducted to solve the interface of a GILZ/HDAC7 interaction. Project 6 leveraged the interaction between Keap1 and the transcription factor Nrf2 to develop an open-source software that enabled the largest high-throughput in silico screening possible to date. In addition, experiments were conducted to solve the structure of Keap1 in complex with inhibitors found in those computational screens.

Alcohol steam reforming is a promising source of hydrogen as fuel, and could be improved by the use of an optimal catalyst. The methanol steam reforming reaction, CH3OH+H2O --> 3H2+CO2 frequently conducted by means of a Cu/ZnO catalyst. Unfortunately, this catalyst deactivates quickly and is pyrophoric. Pd catalysts are much more stable, but reactions using these catalyst follow the decomposition pathway, CH3OH --> 2H2+CO. PdZn alloys can achieve the desired selectivity, and have been noted to form under reaction conditions from Pd/ZnO heterogeneous catalysts. In the present work, careful synthesis techniques of specific support and nanoparticle surfaces have been developed to gain a better understanding of the interaction between each phase. Synthesis focused on preferential exposure of the most active surface of each material. In the case of ZnO, the polar facets of the crystallite were desirable. These high-energy surfaces are less commonly exposed than non-polar facets in typical powders. Tailored platelet shapes were produced in solution by restricting the growth along the (0001) direction, producing thin crystallites. The surfaces of these crystallites were primarily (0001) surfaces, and \\emph{en masse} constituted a high surface area powder, ideal for use as a catalyst support. For the Pd nanoparticle phase, small particles are necessary for high activity. Synthetic techniques to produce nanoparticles typically use organic capping material, which was shown here to be detrimental to the overall activity. A simpler technique was developed in which methanol was used to reduce a Pd precursor in solution without capping agents. This method was effective when depositing Pd on carbon, and has been shown to be strongly dependent on surface chemistry when used with oxide supports. By manipulating the oxide surface with simple solvents, this technique has been generalized for the synthesis of supported nanoparticle catalysts.

Dental alloys, and later zirconia, have been used in dentistry as frameworks for many years in making crowns and bridges veneered with ceramic e.g. feldspathic porcelain. Such methods of restoring teeth have been extensively studied both in the laboratory and clinically. Although such substructures have excellent strength there remains a large properties mismatch between these materials and bone or dentine e.g. elasticity. Furthermore, other drawbacks have been documented such as possible allergies, colouring of alloy margins, veneer chipping and excessive wear to opposing natural dentition. Polyaryletherketone (PAEK) thermoplastic biomaterial polymers such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) have been successfully applied in different medical applications with the latter recently being introduced to dentistry as a restorative material. The material is called Pekkton® ivory (Cendres+Métaux, SA, Switzerland) and is proposed to be used for fabricating both monolithic and bi-layered structures veneered with indirect composite resin. The manufacturer recommends methods similar to well-established restorations such as alloy and ceramic based crowns which makes it a user friendly material for both dental clinics and laboratories. Furthermore, the material’s properties such as high strength, low elastic modulus close to that of dentine, high temperature, chemical, hydrolysis and wear resistance, makes it a promising material for the replacement of tooth material. There is little published data about this material and hence the aim of this research was to evaluate the manufacturing process, aesthetic properties, structural integrity and durability of bi-layered crowns made from PEKK based thermoplastic high performance polymer (Pekkton® ivory, Cendres+Métaux, SA) and veneered with indirect light cured composite (Vita VM LC, VITA Zahnfabrik H. Rauter GmbH & Co.KG, DE). The processing route for Pekkton® ivory is either via milling or hot-pressing and the procedures were compared. The polymer-based restoration was compared to equivalent zirconia and metal based bi-layered restoration systems veneered with either light cured composite resin or feldspathic porcelain. Optical properties of each crown system were compared using a UV and visible light spectrophotometer. Structural integrity was compared for each system by testing the fracture resistance of the crowns using a universal testing machine and durability was evaluated by testing the fatigue limit and fatigue life using a fatigue chewing apparatus. The research hypothesis is that the PEKK polymer as anunderlying substructure material will perform equivalently to metal and zirconia substructures when veneered with light cured composite in the aspects of optical properties, strength and durability. The outcome of the study established a pressing protocol for PEKK using a standard ceramic pressing furnace where the pressed samples showed no significant differences in the CIEL*a*b* colour values, hardness or biaxial flexural strength to those samples produced via milling. There was no significant optical difference between the systems compared, the study found no evidence of difference in the CIEL*a*b* colour value of PEKK, zirconia or metal based samples when veneered with the same composite veneer. However, zirconia based groups displayed greater translucency with the composite veneer and feldspathic porcelain veneer. The fracture resistance of the PEKK and metal composite veneered crowns showed to be comparable, whereas zirconia based crowns demonstrated significantly lower fracture resistance. The durability of the PEKK composite veneered crowns showed the highest fatigue limit in comparison to the zirconia and metal composite veneered crowns. Similarly they showed the highest survival rate in the fatigue life assessment under the same cyclic load. Furthermore, the fracture mode was significantly different than observed with the zirconia and metal based crowns. The conclusion was that this material is promising for use as a restorative material and that clinical evaluation should be undertaken.

Problem: The number of partially edentulous patients is increasing, so the need for RPDs will increase in the clinical practice (Walmsley 2003). One of the most significant disadvantages of current RPDs affecting the health of the remaining oral structures is the unresolved issue of the load distribution between the supporting structures. This is dependent upon materials properties, design and fit of the RPD. A significant need exists to advance the knowledge surrounding this issue and the exploration of novel materials now available for this type of prosthetic treatment. Purpose of study: The aim of this project was to evaluate the RPD frameworks produced from Polyetheretherketone (PEEK) and their load distribution to the supporting structures in comparison to the conventional RPD materials. Further, to enhance the design in order to take advantage of the polymer’s mechanical properties. Therefore, the design will then be adjusted to optimise the load distribution. The objectives for this study were firstly, to use 3D stress freezing digital photoelasticity in dental applications and produce a photoelastic model composed of two materials that have properties representing that of dentin and bone. Secondly, to compare the load distribution of PEEK with that of the conventional materials, and thirdly, to design a PEEK RPD framework for the optimised load distribution. Method and Materials: A 3D digital photoelasticity technique was adapted for use in dentistry to analyse the load distribution of RPD frameworks. A novel photoelastic model was made with individual simulative materials for tooth structure, alveolar bone, PDL, and oral mucosa. For each experiment the RPDs were placed on the photoelastic model and loaded by a modified dental surveyor in the stress freezing oven. The models then sectioned to produce sample slices 2mm in thickness at selected points. The data was collected using Catchsix and CoPA photoelastic softwares packages. Results: Results of the resin model fabrication revealed that the ratio of the modulus of elasticity between Photoelastic materials PL1 and Araldite 2020 epoxy resins at Tg mimic that between dentin and bone. 3D digital photoelasticity was demonstrated to be a valuable technique which allows for viewing of the stresses in the model and the inclusion of digital technology in data processing advances photoelasticity to a modern technique of stress analysis. Results of stress analysis revealed that: • PEEK dimensions and designs should be tailored to the material properties to fulfil the objective of the supporting components • Covering the palatal surfaces of the teeth above the height of the contour in acrylic denture designs assists in transferring some of the applied load to the teeth. • PEEK dentures with a novel clasp design shows potential in comparison to the conventional tissue supported RPD materials. • RPI assemblies are better in load distribution than circumferential and embrasure CoCr designs. This was found to be consistent with other studies. • PEEK dentures with the novel clasp design are comparable in load distribution with that of the RPI assembly design. Conclusion: PEEK is a promising RPD material. The flexibility of this material in combination with novel clasp design transfers the distribution of load in a favourable manner over the abutment teeth. However, further research is needed before it can be accepted as an option in RPD prosthodontics.