Production and characterization of reinforced hydroxyapatite for bone replacement.

PhDHydroxyapatite(HA) is a highly biocompatible calcium phosphate material which in porous form, promotes rapid bone ingrowth and revascularisation. As such it has potential for use as a synthetic bone graft substitute. However, due to poor mechanical strength, its use has been limited to non-major load bearing applications. In response, secondary phase additions such as calcium/phosphate-based glasses have been used to reinforce HA. However, the improved mechanical properties obtained by secondary-phase reinforcement are often associated with decomposition of the HA to tricalcium phosphate(TCP), which may be undesirable due to the increased solubility and controversial biocompatibility of the latter. The aim of this thesis was to produce a calcium/phosphate-based additive for reinforcing HA and to investigate the mechanical and chemical stability of this composite in a physiological environment. Furthermore, the possibility of transferring this technology to porous structures was investigated. Prior to investigating the effects of second phase addition on strength and phase stability, the HA used in this study was characterized as having a biaxial flexural strength (BFS) of 65+11MPa and being chemically stable up to sintering temperatures of 1350°C. Two calcium/phosphate-based additives were produced with Ca/P ratios of 0.5 (CAP I) and 0.8 (CAP2); CAP1 was found to be amorphous, whilst CAP2 was predominantly crystalline in nature where the crystalline phase was primarily Ca2P2O7. The maximal BFS value found for HA doped with 2.5 wt% CAP I (CAPIHA) was 27MPa with up to 73%TCP, whilst the CAP2-doped HA (with 2.5 wt% CAP2) achieved a maximal BFS of 102±21MPa with up to 13%TCP. Thus CAP2HA was judged to be a successful composite suitable for more comprehensive investigation. Studies were carried out to decipher the ideal wt% of CAP2 to promote mechanical reinforcement with a minimal presence of TCP, using 1,2.5 , 3.25 ,4 and 5 wt % CAP2. The results indicated that 2.5 wt% CAP2HA was optimal in terms of both the mechanical and chemical criteria. For investigating mechanical and chemical stability, the HA and CAP2HA samples were soaked in 50% strength Ringer's solution for periods of 1-30 days. HA retained 60% of its original strength, whilst CAP2HA retained 78% of its original strength. In view of the success in using CAP2 as a reinforcing additive, a preliminary investigation was carried out using HA and CAP2HA. This involved development of a technique for producing porous HA, using a reticulated foam template, with a highly interconnected structure and mean porosities and strengths of 66% and 2MPa. Porous samples of CAP2HA were also successfully produced however, only mean porosities and strengths of 75% and 0.6MPa were achieved. This was attributed to processing complications arising from the solubility of Ca2P2O7in water leading to inhibited sintering, which may be overcome by the use of a different binder system

THE MOTIVATION OF WORKING PRACTITIONERS SEEKING A DOCTORAL EDUCATION: FROM THE PERSPECTIVES OF CONFUCIAN LEARNING PHILOSOPHY

This doctoral study explores the motivational orientations of working practitioners pursuing a professional doctoral program who are former and current DPS-IM program students at Syracuse University, School of Information Studies. The found motivational orientations are compared to Confucian philosophy principles of self-cultivation illustrated in The Great Learning (DaXues`å\u3e{t) which is considered the first of a set of Four Books (Sishusl`t). The manuscript\u27s structure consists of a brief of three principles, followed by eight steps that promote individual self-cultivation. Researchers frequently utilize these steps as a connection between civil conduct applied to social and political order (e.g. Keenan, 2011, p. 37). This study uses this Confucian philosophical framework to reveal self-cultivation components related to the motives and aspirations of this select group; Western older adult learners. This study also aims to bridge Eastern motivation theory with Western approaches, making a contribution to both motivational theory and adult education fields of study. This research utilized semi-structured interviews of twenty one DPS-IM students (80.77% participation). Collected data revealed that the majority of the participants were working professionals who have been in their field for at least 10 years. The interview data revealed that self-cultivation was found to be the greatest motivational factor for this study group followed by self-improvement, self-transformation, and sense of responsibility; which are all supported by Confucian learning philosophy found in The Great Learning. This study suggests that even though in modern times, a 2000 year-old Eastern philosophy of learning is synonymous with the motives of adults seeking further education regardless of their cultural background

Dust, Cadmium and Rheumatoid Arthritis

Background Rheumatoid arthritis (RA) is a systemic, inflammatory disease with an estimated global prevalence of 0.3–1.0%. Evidence suggests that RA is initiated in the lungs. Cigarette smoking and various occupations associated with vapour, gas, dust, and fume (VGDF) inhalation can increase the risk of RA development. The association of VGDF, smoking, development of rheumatoid autoantibodies such as rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) and their relationship to RA disease development is poorly understood. Structure There are seven chapters in the dissertation. Chapter 1 introduces the dissertation reasoning and hypothesis. Chapter 2 is a published review of literature on RA and inhaled occupational exposures. Chapters 3 and 4 are published empirical studies analysing the clustering pattern of RF and ACPA, suggesting a potential common autoantigen in RA. Chapter 5 is a published empirical study analysing the pattern of autoantibody development with inhalational exposures to smoking and VGDF in male RA. Chapter 6 analyses the role of cadmium (as a common factor in smoking and VGDF), in relation to autoantibody development in nodular and non-nodular RA. Chapter 7 discusses further the strengths, limitations, unanswered questions and future direction of research. Conclusions Overall, this research provides evidence that RA, particularly in males, is precipitated by inhaled environmental exposures and RA patients with multiple inhalational insults are likely to have higher RF and ACPA levels. Empirical and laboratory evidence suggests a common autoantigen in RA to explain autoantibody clustering. Nodular RA patients demonstrate higher rheumatoid autoantibody levels, and significantly higher cadmium levels were found in female nodular RA patients. A model of heavy metal adsorption onto VGDF particles in vitro is proposed, stimulating pulmonary nodule formation and generating autoantibodies in response to a common autoantigen: post-translationally modified heavy chain fragments of immunoglobulin G

A framework for evaluating the user experience of digital moderation systems in the South African secondary school environment

The continued emphasis on education quality amidst the accelerating pace of technological developments, which create new opportunities, expectations, and challenges in the teaching and learning environment, requires evidence-based, robust, regulatory frameworks for monitoring standards. Innovative and dynamic approaches are required to quality assure assessment processes (moderation). The reviewed literature provided scant evidence of theorization on the concept of digital moderation (eModeration) and little empirical evidence on systems used in secondary schools. This deficiency in the literature in terms of digital moderation is problematic since it leaves educators, managers, and researchers without evidence-based guidance on how eModeration systems should be designed or evaluated. This deficit provides the rationale for an investigation into the components of a framework to evaluate the user experience of an eModeration system. This study draws on the extant eModeration literature and theories of technology acceptance, Information Systems success (IS) models, and constructs from the field of Human-Computer Interaction (HCI) to create a theoretical framework that integrates constructs identified from the different literature streams to evaluate an eModeration system's user experience. A Design Science Research (DSR) approach guided the design, development, and evaluation of an eModeration evaluation framework. A Participatory Action Design Research (PADRE) approach was used to position the user within the iterative DSR cycles as a means of knowledge acquisition. Participatory Design (PD) was positioned as a data collection strategy during requirements gathering and the generation of design ideas for an eModeration prototype system. Qualitative and quantitative data collection was used to record perceptions of individuals interacting with the prototype. The theoretical contribution is the literature-based framework underpinning this study. This theoretical framework was used as input in determining the components of an eModeration evaluation framework, which is the main contribution of this study. This research has practical value in guiding the design of evaluation criteria for the user experience of an eModeration system for implementation in secondary schools.School of ComputingD. Phil. (Information Systems

Modelling Contracts and Workflows for Verification and Enactment

The work presented in this thesis concerns some aspects related to the Modelling of Contracts and Workflows for Verification and Enactment. We have sought to gain some insight into the nature of contracts and workflows. in order that we may model them. primarily, for the purposes of verifying certain properties and for enacting them. Workflows help coordinate the enactment of business processes. A notable aspect of workflow technologies is the lack of formal semantics for workflow models. In this thesis, we consider the characterisation of workflow using a number of formal tools, viz. Milner's CCS, Cleaveland et ai's Prioritised CCS (which we abbreviate to PCCS) and the Situation Calculus (thanks mainly to Reiter), which is based on First-Order Logic. Using these, we provide formalisations of production workflows, which are somewhat rigid, inflexible structures, akin to production lines. We do so, in order that we may fiJo: their operational meaning for the purposes of verification and enactment. We define the Liesbet meta-model for production workflow to provide a reference ontology for the task of formalisation. We have also implemented a framework for the verification and enactment of Liesbet workflow models. Regarding verification, we are particularly interested in the key property of soundness, which is concerned with an absence of locking and redundant tasks in a workflow model. Our framework is capable of verifying this property of workflow models, as well as arbitrary temporally-extended constraints', which are constraints whose satisfaction is determined over successive states of enactment of a model. We also consider the definition of more flexible workflows, including collaborative workflows, using an approach that we have conceived called Institutional Workflow Modelling (IWM). The essence of IWM lies (in part) in the identification that the structure of a workflow model necessarily entails the existence of counts as relations. These relations prescribe how the occurrence of certain actions, in the context of a particular workflow model. count as the occurrence of other actions. We have also been interested in the modelling of contracts; and have found IWM to be useful as a foundational basis for contract modelling. ????????? Another fu.ndamental aspect of our IWM-based approach is a correspondence, which we have identified, between counts as relations and methods in Hierarchical Task Network (HTN)-based planning. Thus, we are able to advocate the use of an HTN-based planning framework for the verification of flexible workflows and contracts. We have implemented such a framework, whose planner is called Theodore. We define a sjmilar notion of soundness for flexible workflows and contracts, which the Theodore-based framework is able to verify, along with arbitrary temporallyextended constraints.Imperial Users onl

Usability analysis of contending electronic health record systems

In this paper, we report measured usability of two leading EHR systems during procurement. A total of 18 users participated in paired-usability testing of three scenarios: ordering and managing medications by an outpatient physician, medicine administration by an inpatient nurse and scheduling of appointments by nursing staff. Data for audio, screen capture, satisfaction rating, task success and errors made was collected during testing. We found a clear difference between the systems for percentage of successfully completed tasks, two different satisfaction measures and perceived learnability when looking at the results over all scenarios. We conclude that usability should be evaluated during procurement and the difference in usability between systems could be revealed even with fewer measures than were used in our study. © 2019 American Psychological Association Inc. All rights reserved.Peer reviewe

The design and management of diverse affiliations : an exploration of international hotel chains

The simultaneous use of different market entry methods by international service firms is creating complex and compound organisations that operate within and across organisational boundaries. These organisations face variable risks related to control, resource commitment, flexibility and dissemination across their diversely affiliated portfolios. This research seeks to explore how these risks are managed within these diverse affiliations through an investigation of organisational and inter-organisational design. This study draws on three fields of literature; international market entry, alliance and networks, and organisation design. A number of gaps have been identified in this literature relating to 'how' international service firms, inter-organisational alliances, diverse affiliations and international hotel chains are designed and managed. Using international hotel chains for the primary investigation, a qualitative case study approach was adopted for this study. The research was conducted in three phases; the first served to verify the extent of the phenomenon under study, the second provided insight into organisation design within firm boundaries and the third revealed a detailed picture of inter-organisational design. A major contribution of this study is the identification of communities of design within diversely affiliated organisations. These communities are created through the different structures and processes employed across portfolios and reinforced by the perceptions of organisation members. Barriers can develop between the communities that limit the degrees of control and flexibility achieved and inhibit organisational potential. A further contribution of this study is the development of a relational-process framework that can be used to build bridges across these communities, break down barriers and enhance relational ties, but only if supported by appropriate control procedures. Managers are recommended to consider the impact of formal mechanistic structures within and across organisational boundaries and the impact of inter-organisational processes on relational ties in designs that cross organisational boundaries in order to enhance the potential of diverse affiliations

Evaluating performance for procurement: A structured method for assessing the usability of future speech interfaces

Procurement is a process by which organizations acquire equipment to enhance the effectiveness of their operations. Equipment will only enhance effectiveness if it is usable for its purpose in the work environment, i.e. if it enables tasks to be performed to the desired quality with acceptable costs to those who operate it. Procurement presents a requirement, then, for evaluations of the performance of human-machine work systems. This thesis is concerned with the provision of information to support procurers in performing such evaluations. The Ministry of Defence (an equipment procurer) has presented a particular requirement for a means of assessing the usability of speech interfaces in the establishment of the feasibility of computerized battlefield work systems. A structured method was developed to meet this requirement, the scope, notation and process of which sought to be explicit and proceduralized. The scope was specified in terms of a conceptualization of human-computer interaction: the method supported the development of representations of the task, device and user, which could be implemented as simulations and used in empirical evaluations of system performance. Notations for representations were proposed, and procedures enabling the use of the notations. The specification and implementation of the four sub-methods is described, and subsequent enhancement in the context of evaluations of speech interfaces for battlefield observation tasks. The complete method is presented. An evaluation of the method was finally performed with respect to the quality of the assessment output and costs to the assessor. The results suggested that the method facilitated systematic assessment, although some inadequacies were identified in the expression of diagnostic information which was recruited by the procedures, and in some of the procedures themselves. The research offers support for the use of structured human factors evaluation methods in procurement. Qualifications relate to the appropriate expression of knowledge of device-user interaction, and to the conflict between requirements for flexibility and low-level proceduralization

Identifying knowledge transfer barriers within a complex supply chain organization

This research is concerned with understanding how organizational performance can be improved through effective knowledge transfer. In particular, the researcher is interested in organizational performance as it relates to those organizations that rely on core horizontal business processes, such as those found within a supply chain. Many organizations develop knowledge strategies to try and utilise existing knowledge within their organizations. However, this process tends to be developed from a top-down perspective, and deployed on an organization-wide basis. It is the researcher’s contention that this is not a suitable approach for developing an effective knowledge strategy for supply chain / complex organizations. It is the researcher’s belief that in order to develop and define a suitable method for knowledge strategy development and implementation, how knowledge and information are created and shared along core business processes must first be understood. To do this it is important to identify the barriers that impact knowledge transfer across an organization, and more specifically, along core business processes. By mapping a core IBM supply chain process, and identifying the employee work groups associated with the process (through social network analysis), the researcher was able to identify and assess knowledge transfer barriers, and how they impact along the IBM order flow process. Through a combination of qualitative and quantitative methods the researcher developed an emergent theory concerning how organizations should approach the identification and management of knowledge transfer barriers