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The development of a robotic system for zygomatic implant placement
Get PDFOral rehabilitation with zygomatic implant placement is a predictable treatment option to restore the function of lost maxillary dentition. It is particularly indicated in cases of severe resorption of the maxilla and also after maxillectomies.
Today, the placement of almost all dental implants including zygomatic implants is achieved with the aid of a physical or a digital guide. Static guides are widely used to physically guide the placement of dental and zygomatic implants. Dynamic navigation technology provides digital guidance through monitoring of a computer screen during the implant osteotomy preparation and implant placement. Robotic-assisted implant dentistry can be regarded as a combination guide in the sense that it provides haptic physical guidance in addition to the digital real-time monitoring of the drilling stages on screen.
On the other hand, robotic placement of dental and zygomatic implants also relies on digital guidance principles, but the drilling and implant placement is not performed by a human operator. This technique has shown to produce a highly predictable accuracy in conventional dental implants and also demonstrated promising results with zygomatic implants. A deeper analysis of the possible sources of error involved in the digitally guided zygomatic implant placement techniques would inform the surgeons and may lead to better treatment outcomes in relation to placement accuracy. Such level of analysis would also benefit operators performing digitally guided conventional dental implant placement as it has not been done with this type of implants either.
Chapter 1: reviews the literature in relation to the importance of accurate implant positioning, the revolution of digital planning and guiding protocols, including robotic-assisted and robotic-guided approaches.
Chapter 2: is presented as a published journal article. This chapter analysed the registration error; one of the major human-related sources of error for the digital guidance protocol. This analysis served to optimise and standardise the registration process for the next stages of the project, by selecting the configuration of registration markers expected to produce the best registration accuracy
Chapter 3: is presented as a published journal article. This chapter investigated the precision of drill calibration; another major human-related sources of error for the digital guidance protocol. The results served to optimise and standardise the drill calibration process for the next stages of the project, by selecting the best single drill that is expected to produce the best drill calibration accuracy.
Chapter 4: describes the processes involved in the initial development and testing phases of the integrated robotic system.
Chapter 5: is presented in the traditional chapter format. This chapter includes the final phases of in vitro testing of the newly developed integrated robotic system in this project. This blindly-analysed comparative study investigated the application error (i.e., execution error); the last major human-related source of error for the digital guidance protocol. The control groups involved operator placement under digital guidance (i.e., dynamic navigation) while the test group involved task-autonomous robotic placement using the new system.
In conclusion, this project investigated (in vitro) the accuracy of a newly developed dynamically guided robotic system to achieve zygomatic implant placement. The results demonstrated that the robotic system is highly accurate with clinically acceptable margin of errors. The translation into clinical application would require further developments mainly pertaining to the automation of the preparatory and within-procedure checks as the process was time-consuming when compared to manual placement. The project also contributes to our knowledge of the magnitude of the possible human-related sources of error in placing zygomatic implants under dynamic navigation guidance and suggests solutions to minimising them whether in vitro or in clinical scenarios
Needs of Omani children during their transition from KG2 to first grade: a case study of stakeholders’ perspectives
Get PDFChildren learners’ experiences can have a long-lasting influence on their future well-being, active participation both in school and life, and academic success. The purpose of this research is to shed light on children’s transition from KG2 to first grade, its general situation, and children’s needs during this time from their viewpoint as well as those of the stakeholders involved in this issue. Theoretically, this study builds on two perspectives of experience: Dewey’s concept of the continuity of experience and the notion of boundary objects, CHAT, as introduced in 1978 by Vygotsky. The study followed a multimethodological design that incorporated gathering the perceptions of relevant stakeholders and children’s experiences in this area, along with the effects of cultural and historical influence, through semi-structured interviews and focus groups. Data validation included triangulation via observation. Stakeholders included nursery teachers, primary one teachers, nursery and primary school principals, curriculum developers for kindergarten and first grade, nursery and primary supervisors, policy makers, and parents. Data collection also included children’s drawings and visual narratives, along with research field notes and observations of first-graders in the classroom at the beginning of the school year, in order to illustrate young learners’ experiences in nursery school and first grade. Data analysis entailed identifying main motives and needs and exploring through the lens of the underpinning theories whether the children’s experiences demonstrated continuity. The theoretical framework and study findings guided the development of the suggested model, which presents the theory behind it: community, continuity, and public content. It was designed according to Fullan's framework and the theories of CHAT and Dewey as the theoretical framework for the study, in a summary on an illustration explaining its components and steps. It is developed to bring about positive change in the issue of transition of children from KG2 to first grade and secure the future for young learners
Accountability and issue politics: a case of shale gas extraction in a Chinese province
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The prediction of purification conditions for automated chemistry
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Does learning to perceive English vowels help in perceiving English lexical stress? The case of Arab learners of English: a longitudinal study
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Eastward spread of Western learning and knowledge transfer: the translation and interpretation of The Wealth of Nations in Late Qing China (1840-1912)
No full textAbstract not currently available
The impact of Candida albicans phenotype on the oral microbiome
Get PDFCandida albicans is a prolific opportunistic pathogen and resides within the mucosa associated microbiome in the human body. The presence of Candida albicans has commonly been reported as a potential indicator or risk factor in the development of caries in children and adults. Typically commensal in nature, it has also been well established that the development of pathogenicity in Candida albicans is driven by environmental factors which lead to its overabundance or phenotypic switching to a more pathogenic hyphal morphology. While this has been found to aid in adhesion to oral surfaces, both biological and inert, it also provides a substrate and environmental niche for other micro-organisms. In this study, we propose that alteration of Candida phenotype directly influences the microbial and cariogenic profile of a fixed model biofilms and complex, undefined biofilms.
Firstly, by employing a meta-analytic approach to examining relevant media related to the oral microbiome to synthesise findings which examine the influence of bacteria within the microbiome and the ability to predict onset or development of caries based on these findings. Following this, C albicans isolates with high and low biofilm phenotype were selected for co aggregation assessment with other organisms of a previously published “caries” biofilm model and profiled based on biomass, metabolism, drug response and response to environmental stimuli such as sucrose. Saliva was pooled from 19 individuals and used as starter biofilm culture for ex-vivo experiments ex-vivo models were grown on bovine enamel and assessed for shifting microbial profile, acidogenesis and alteration of substrate when exposed to environmental stimuli. Additionally, Complex bacterial biofilms ± Candida albicans were formed over 5 days ± fluconazole (FLU) or amphotericin B (AMB), with biofilms sampled every 24 h for 120 hrs. DNA was extracted with propidium monoazide to amplify live cell DNA. Microbiome analysis was performed using long read Nanopore sequencing.
Analysis of the literature containing 16S rRNA sequencing data relating to caries revealed insights into the collection, curation, and storage of sequencing data which highlighted a lack of standardisation in the field. In addition, though some significance was found between studies, it was determined that more data would be required to be able to reliably use microbiome data as a predictive tool for caries pathology. When screening isolates, C albicans was found to buffer pH profile of “caries” organisms in both dual and multi-species formats. Using sucrose as an environmental stimulus of multi-species biofilms resulted in both a shift in microbial distribution and a higher erosion profile in bovine enamel. Additionally, Candida was shown to influence the distribution of organism taxonomy in a complex saliva-derived ex-vivo model where it was also identified that environmental conditions such as media requirements, substrate development and challenge through oral hygiene regimen or antifungal exposure can also impact the oral microbiome. Overall, Candida was shown to provide a key role in the oral in-vitro microenvironment, in the context of caries, and in a strain-dependent manner, using in-vitro and ex-vivo methods. This has implications in both the application of strains of C. albicans in fixed models for testing of novel compounds and in applications of personalised healthcare where the ramifications of affecting these core organisms, via antimicrobial interventions, could have further, unexpected effects
Converging environmental and genetic risk factors during embryonic development of mice cause lasting, long-term behavioural and neurobiological changes relevant to schizophrenia
Get PDFSummary available: pp. ii-v
Effects of home-based resistance exercise programmes on muscle fitness, well-being, thoughts and perceptions of healthy adults
Get PDFResistance or strength exercise produces several health benefits including an increase in muscle mass, muscle strength, improvements in body fat, metabolic rate, glycaemic control, blood pressure, blood lipid profile, flow-mediated dilatation and cardiorespiratory fitness. World and UK physical activity (PA) guidelines suggest performing at least two days a week muscle-strengthening activities involving major muscle groups. However, less than half of the UK and Scotland’s adult population achieve the recommended guidelines. Different barriers towards strength exercise have been identified, such as lack of time, family constraints, not having the equipment, inadequate knowledge, and financial barriers, among others. Home-based resistance exercise programmes with a low time commitment that involve bodyweight exercises and resistance bands could be a solution to overcome the barriers and increase the number of people performing strength exercise. This thesis aimed to explore the effects of two home-based resistance exercise programmes on muscle strength, muscle endurance and thickness in healthy adults. Additionally, it aimed to explore participants’ experiences, thoughts, tolerance and acceptability of the homebased resistance exercise programmes.
Firstly, twenty-six healthy adults (n=22 female, n=4 male) and underwent a 12- week intervention (ONE Study) (Chapter 2). Participants were randomised (1:1) to a control group (N=14, n=12 female, n=2 male) and a resistance exercise group (RE) (N=12, n=10 female, n=2 male). Participants in the CG were asked to keep their normal PA levels, while the RE group was asked to do a home-based resistance exercise programme of performing one minute of resistance exercise per day, for six days a week (one exercise per day with one day rest). Muscle strength, muscle endurance, body composition and anthropometry were measured at baseline, 4-week, 8-week and post-intervention. Muscle thickness was measured at baseline and post-intervention. No significant changes were found for muscle strength, muscle endurance, muscle thickness, anthropometry and fat mass. There was a significant Time*Group interaction in fat free mass (p=0.025), with a significant linear trend for the control group (p=0.009), experiencing a decrease in fat free mass of 1.11 kg between baseline and postintervention. A subgroup of the RE group took part in qualitative semi-structured interviews (N=7). Thematic analysis and framework analysis were used. The analysis generated 13 themes, including physical activity before the study, reasons for joining the study, instructions and learning, programme of daily life and planning, perceptions of the programme, self-monitoring, impact of the programme, motivators for physical activity, barriers and facilitators, health, suggestions for the programme, selling the programme and other. The main finding is that convenience, enjoyment, progression, a sense of achievement and receiving the benefits of the strength exercise were important for participants in order to do the exercise programme and continue to do it in the long term.
Secondly, seventy-five participants underwent 12-week online intervention (REFLEX Study) (Chapter 3). Participants were randomised (1:1) into a flexibility exercise group (N=36) and a RE group (N=39). Participants in the flexibility exercise group were asked to do at least one set of flexibility exercises per muscle group (six muscle groups in total) per week. Participants in the RE group were asked to do at least one set of resistance exercises per muscle group (six muscle groups in total) per week. All participants could choose to do up to three sets per muscle group. The intervention was delivered through a webapp. Muscle endurance (push-up test, half-squat test and plank test), flexibility (sit-andreach test), well-being, self-esteem, vitality and energy, exercise motivation, adherence, volume and frequency of exercise were measured. No significant changes were found in muscle endurance and flexibility, well-being, selfesteem, vitality and energy and energy motivation outcomes. Only 57.9% of the RE group and 55.6% of the flexibility group completed 80% of the minimum amount of exercise prescribed. The RE group started the intervention with 7 sets per week (mean) but decreased to four sets by week 12. The flexibility group started the intervention by doing nine sets per week (mean) and also decreased to three sets by week 12. Many participants in both groups chose to do all of their exercises on one day per week. Finally, a subgroup of the REFLEX Study took part in qualitative interviews (RE group N=11;Flexibility group N=10). Similar results to the ONE Study were found in the REFLEX Study. Additionally, understanding instructions and being able to follow them emerged as essential for doing the exercises properly and self-monitoring. Participants also reported that competing priorities and external circumstances affect how they managed to fit the exercises into their everyday lives. Finally, personal and external accountability were major motivators to do the exercises during the programme.
This thesis showed that these two home-based resistance exercise programmes did not have a significant effect on muscle fitness, flexibility, anthropometry, fat mass, well-being, vitality and energy, self-esteem and exercise motivation regulation. However, they did have a significant effect on fat free mass. Finally, it showed that convenience, enjoyment, a sense of achievement, experiencing the effects of strength exercise, progression and variety of exercises are important to start doing resistance exercises and continuing to do them
Power-based value capture over punctuated time: cashmere supply chains and business continuity
Get PDFSupply chain management (SCM) assumes collaboration is central to good practice and profitability. Empirical research shows that practitioners frequently choose opportunism over collaboration, and supply chain collaboration (SCC) requires appropriate cultures, resource complementarity, and incentives to succeed. This research further investigated this issue by exploring how cashmere value chain collaborative alliances sustain power-based value capture over punctuated time.
A qualitative longitudinal single case study of cashmere value chains was used for localised theory building. Data was collected from historical documentation, 30 semi-structured interviews and onsite observations before conducting a thematic analysis. The findings revealed that firms inherit power-based value capture depending on the relative value of their resources for a business opportunity. High-power firms adopt adversarial relationships and trap partners into illusionary collaborations over multiple business cycles. The longer opportunism cycles last, the harder it is for firms to break free as unfavourable conditions transform into cultural norms. Alternatively, low-power firms use genuine collaborations to mitigate opportunism cycles. If relationships continue without change, high-power firms can also become hostage to their growing convenience and sunk cost-based dependencies from long-established illusionary and genuine collaborations.
The opportunism cycle concept validates and extends the inter-partner learning theory and, to a lesser extent, Power theory and Path Dependence theory. First, it extends Hamel's priority shifts and external disruptor concepts by showing that these elements determine business developmental paths and validate the path dependence theory concept of multiple lock-ins. It also extends Hamel's concept of competitive collaboration by showing that firms can use illusionary collaborations to trick partners into creating psychological slack to extend the value capture potential beyond the limits of psychological slack. It validates that Khanna’s predicted scenarios (three-legged fallacy, hesitant winners and reluctant losers) can occur passively but also shows how firms can actively create them. Second, it validated all six power bases and their relevance to different stages of the opportunity cycle, forming an effective tool for manipulating perceived power dynamics. It also contradicted Cox's assumption that collaborations do not account for power dynamics by showing that they do by actively avoiding their consideration. Third, it validated the power architecture theory prediction that network embeddedness facilitates opportunism rather than collaboration over time. Fourth, it identified path-breaking processes to extend the path dependence theory. On a practical level, the research explained that collaborations fail because practitioners fail to distinguish between genuine and illusionary collaborations and showed how practitioners can recognise when to implement and avoid opportunism cycles. The research concluded by identifying the need for future studies to adopt more advanced research methodologies and explore the implications of instant access to difficult-to-acquire resources
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