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Diffusion kinetics in crystals
No full textIn this study, the full diffusion kinetics behaviour for phenomenological coefficients, interdiffusion coefficients and tracer diffusion coefficients of atomic components in crystalline solids is investigated. The main theoretical approach for this investigation is the hierarchy of random alloy approximations. The combined analysis of tracer or self- diffusion coefficients with the interdiffusion coefficient is also performed. The basic information on the interrelation of the tracer and collective diffusion processes is provided by the chosen theory of diffusion kinetics. Furthermore, extensive Kinetic Monte Carlo (KMC) simulation results are used for the testing and development of analytical diffusion kinetics approaches for binary and multicomponent alloy systems. As part of the present research, the solution to a problem that is often encountered in the experimental investigation on the self- and interdiffusion coefficients is considered. Namely, in the case of a binary alloy it is often necessary (via the Darken-Manning equation) to find the tracer diffusion coefficient where the other tracer diffusion coefficient and interdiffusion coefficient are available. Several numerical tests are performed to examine the solution and compared them with the available experimental data. Further, in this study, the diffusion kinetics formalisms of Darken, Manning, Holdsworth and Elliott (HE), and Moleko, Allnatt and Allnatt (MAA) are analysed in detail. These formalisms are then extended and applied for the cases of multicomponent random alloy models. Moreover, a new version of the highly accurate MAA theory, called MAA-light, is developed for describing diffusion kinetics in multicomponent random alloys. In addition, the resulting expressions from the approaches are verified by means of KMC simulation and the possible range of the tracer diffusion coefficient ratio of the highest atomic mobility to the lowest atomic mobility is analysed. It is shown that the overall results for the theories are in reasonably good agreement with the simulation results. An iterative method for the case of the multicomponent system is also developed to find the uncorrelated parts of the tracer diffusion coefficients and tracer correlation factors with reasonable accuracy. In this research, the diffusion kinetics theory is focused on a special type of multicomponent alloy, namely, high entropy alloys (HEAs). The self-diffusion and interdiffusion kinetics are investigated by extending and applying three diffusion kinetics approaches in the case of the face centred cubic high entropy alloy CoCrFeMn0.5Ni
Elucidating the mechanisms of steroid-resistant asthma
No full textSevere, steroid-resistant (SSR) asthma is of considerable clinical and economic significance as affected individuals do not respond to mainstay corticosteroid therapies. Patients with SSR asthma experience more frequent exacerbations of disease, are more likely to require hospitalisation and have a poor quality of life. Improved therapies are urgently required for SSR asthma, however, progress in this area has been hampered by a lack of understanding of the pathological processes that underpin disease. The major obstacle to understanding the processes that drive SSR asthma is that there are several subsets of the disease characterised by different inflammatory and immunological phenotypes. This heterogeneity disease makes pinpointing the key processes that underpin disease extremely difficult in humans.
To help understand the mechanisms that underpin SSR asthma, we have developed three unique infection-induced models of SSR asthma. As part of my thesis, I have also developed a high fat diet-induced, obesity-associated SSR asthma. Together, all four models recapitulate the key features of a number of different subsets/clusters of SSR asthma in the clinic and represent useful tools to understand subset-specific and universal factors/processes that underpin of disease and test novel therapies that target the factors/processes identified.
The overarching aim of my PhD is to utilise these models to elucidate novel mechanisms that may underpin SSR asthma and to determine whether targeting these mechanisms with therapeutic interventions can suppress disease, where steroids are not effective. My PhD was divided into three major aims that have focused on discovering novel factors associated with disease and assessing the roles played by known associative factors potentially drive steroid resistance. Firstly, I conducted array analyses on whole lung tissue from our three models of infection-induced SSR asthma, that represent different inflammatory and immune subsets observed in the clinic, to identify factors that are universally dysregulated in disease. I identified 11 universally dysregulated genes, most of which have not been previously recognised in SSR asthma (chapter 2). I then showed the functional role that one of these factors may being playing in driving SSR asthma (chapter 2).
Secondly, I have identified dysregulated antioxidant responses as playing a critical role in our Chlamydia-induced model of SSR asthma and show that restoration of antioxidant responses may be a beneficial adjunct therapy for steroid-resistant disease (chapter 3).
Lastly, I have developed a new murine model of high fat diet (HFD)-induced obesity that induces SSR allergic airways disease (AAD) (chapter 4). I used this model to identify a previously unrecognised role for HFD/obesity-induced, NLRP3 inflammasome-mediated responses in the lung the development of steroid-resistant airways hyper-responsiveness (AHR). I also show that HFD/obesity induced NLRP3 inflammasome responses in the lung may be therapeutically targeted for the treatment of HFD/obesity-associated, steroid-resistant AHR.
Together the findings from my PhD studies inform new mechanisms and pathways that may underpin SSR asthma in the clinical setting and highlight potential therapeutic targets and strategies for the treatment of disease. The development of a representative obesity-induced model of SSR asthma will be a useful tool for future studies that aim to identify mechanisms and treatment strategies for obese SSR asthmatics
Rectal protection in prostate stereotactic radiotherapy: a retrospective exploratory analysis of two rectal displacement devices
No full textIntroduction: High rectal doses are associated with increased toxicity. A rectal displacement device (RDD) reduces rectal dose in prostate stereotactic body radiation therapy (SBRT). This study investigates any dosimetric difference between two methods of rectal displacement (Rectafix and SpaceOAR) for prostate SBRT. Methods: Rectal dosimetry of 45 men who received SBRT within the PROMETHEUS trial was retrospectively examined, across two radiation therapy centres using the two RDD's. Men received a total dose (TD) of 19 or 20 Gy in two fractions followed by 46 Gy in 23 fractions. Centre 1 contributed 16 Rectafix and 10 SpaceOAR patients. Centre 2 contributed 19 Rectafix patients. Rectal dose volume histogram (DVH) data were recorded as a TD percentage at the following volume intervals; V1%, V2%, V5%, V10% and then 10% increments to V80%. As only one centre employed both RDD's, three sequential rectal dosimetry comparisons were performed; (1) centre 1 Rectafix versus centre 1 SpaceOAR; (2) centre 1 Rectafix versus centre 2 Rectafix and (3) centre 1+ centre 2 Rectafix versus centre 1 SpaceOAR. Results: In comparison (1) Rectafix demonstrated lower mean doses at 9 out of 11 measured intervals (P = 0.0012). Comparison (2) demonstrated a moderate difference with centre 2 plans producing slightly lower rectal doses (P = 0.013). Comparison (3) further demonstrated that Rectafix returned lower mean doses than SpaceOAR (P < 0.001). Although all dose levels were in favour of Rectafix, in absolute terms differences were small (2.6-9.0%). Conclusions: In well-selected prostate SBRT patients, Rectafix and SpaceOAR RDD's provide approximately equivalent rectal sparing
Prime Cuts
No full textHoping to incentivise funding approval for the expansion of the Newcastle Region Art Gallery, its owners proposed to fast track the demolition of a temporary building on its site, the Children’s Art Pavilion. To promote a process of deconstruction for the Art Pavilion in preference to a more typical process of demolition, a series of 7 short films, Prime Cuts, described how a significant local landscape, captured within an image, were piecemeal transformed to depict the Art Pavilion as part of that landscape. The project also included the mapped projection of a 20 minute film, One Of These Days (developed around ideas within the Pink Floyd song of the same name), on to two panels of the Art Pavilion. On the night before the deconstruction of the Art Pavilion began it was shown through the evening to passers-by, and to an audience who gathered in the street
Building resilience of urban slum settlements: a multi-sectoral approach to capacity building
No full textThis report has been prepared by Architects Without Frontiers (AWF) under the project Building Resilience in Urban Slum Settlements funded by the AusAID Innovations Fund and implemented in partnership
between Habitat for Humanity Australia (HFHA) and Habitat for Humanity Bangladesh (HFHB), together with a local partner NGO, Participatory Development Action Program (PDAP). This was a 1-year pilot
project implemented from July 2012 to June 2013. Technical support was provided by AWF and Arup. This report provides an overview of the project and presents the key lessons learnt that have implications for
future work. The project was targeted at an urban slum community of 650 households known as Talab Camp in Mirpur in the north-western part of Dhaka. During the 1947 India-Pakistan partition, Hindu-Muslim communal strife led to large numbers of Muslim refugees, particularly from the Indian state of Bihar, to flee into East Pakistan. When East Pakistan seceded from West Pakistan and formed Bangladesh in 1971, the Biharis, who sided with West Pakistan at that time, were contained in refugee camps by the Bangladeshi government to separate them from the mainstream Bangali population and thereby avoid potential ethnic
conflict; hence the name “camp”. There were a number of other such “Bihari camps” around Talab Camp. Being an ethnic community, it still faced the difficulty of assimilation into the mainstream Bengali society even after more than 65 years, despite being granted Bangladeshi citizenship in 2008. Given that this was a marginal community, and hence poor and vulnerable, there was a strong rationale to implement the project there. Additionally as the community was protected under the Geneva Convention for Refugees, it provided an opportunity to work there as it was safe from eviction drives
The representations of life outside Vietnam in first-year technical university textbooks in Hanoi and their influence on students’ intercultural communicative competence in English learning
No full textEnglish Language Teaching (ELT) textbooks are an indispensable component in language classrooms to transport cultural elements, societal values, and attitudes as well as language knowledge, to support the process of foreign language acquisition (Rajabi & Ketabi, 2012). Designed for the purpose of international use, these commercial ELT textbooks expose learners to foreign perspectives embedded in cultural representations. In many Southeast Asian countries where English is spoken as a foreign language, ELT textbooks are the predominant source of language and culture that learners are exposed to. In Vietnamese non-major universities, commercial ELT textbooks are sometimes the only source of language input, which to some extent, offer undeniable and remarkable advantages in providing the context of lessons and classroom practice (Nguyen, 2011).
Important as they may be, little is known about ELT textbook choice, and foreign cultural representations in these ELT textbooks in Vietnamese tertiary education. This study examines the current textbook use in ten technical universities in Hanoi, which are the representatives of non-major universities in Vietnam. This study not only focuses on the representations of culture as life outside Vietnam in these ELT textbooks but also investigates how these cultural differences influence students’ development of intercultural communicative competence in language learning.
The study was conducted in three phases: phase one (administrator interviews and textbook collection), phase two (textbook analysis) and phase three (teachers and students’ interviews). In phase one, structured interviews with Heads/Vice Heads of Language Faculties identified a corpus of similar and different current ELT textbooks and the context in which these textbooks were used. Phase two focused on the cultural representations of life outside Vietnam in these textbooks, applying a sources of culture model (Cortazzi & Jin, 1999), and senses of culture framework (Adaskou et al., 1990). The findings demonstrate a predominance of foreign cultural representations, with strong focus on British-American and European cultures, and an underrepresentation of the source culture (Vietnamese culture in this context) and many different international cultures. Phase two also discovered a similar pattern to these textbooks emphasising the sociological and aesthetic sense of culture, with less emphasis on the semantic and pragmatic senses. In phase three, semi-structured interviews with teachers and students were conducted to explore how students and teachers perceived and responded to these representations in their learning and teaching activities. The data analysis in this phase observed a strong agreement of teachers and students on the patterns of cultural representations in these textbooks. This phase also identified multiple teachers and students’ views of the influence of cultural representations on students’ intercultural communicative competence and their cultural teaching pedagogies.
The research has revealed four key issues: The issues arising from the current provisions of technical university English Foreign Language (EFL) programs and the course objectives toward students’ intercultural communicative competence (ICC); the issues arising from the representations of life outside Vietnam embedded in Vietnamese technical university textbooks and the development of students’ ICC; the issues arising from Vietnamese technical university students’ learning interests and their development of ICC; and the issues arising from Vietnamese technical university EFL teachers’ cultural teaching practices and the development of students’ ICC. From the four discussions, I propose recommendations to improve technical university students’ ICC. These recommendations include the course provisions, the cultural content and culture-based activities that may be applied to technical university contexts to develop students’ understanding of cultural differences and their ICC
On the Batchelor constant in decaying isotropic turbulence
No full textDirect numerical simulations of a passive scalar mixed in decaying homogeneous isotropic turbulence indicate that, when the Schmidt number is close to or exceeds unity, the Batchelor constant is about 3. This is smaller by nearly a factor of 2 than that inferred from stationary turbulence simulations. In the present case, Batchelor's spectrum approximates the present data well in the viscous-convective range while Kraichnan's spectrum provides a very good fit at large wavenumbers
Effectiveness of a pragmatic school-based universal intervention targeting student resilience protective factors in reducing mental health problems in adolescents
No full textWorldwide, 10–20% of adolescents experience mental health problems. Strategies aimed at strengthening resilience protective factors provide a potential approach for reducing mental health problems in adolescents. This study evaluated the effectiveness of a universal, school-based intervention targeting resilience protective factors in reducing mental health problems in adolescents. A cluster randomised controlled trial was conducted in 20 intervention and 12 control secondary schools located in socio-economically disadvantaged areas of NSW, Australia. Data were collected from 3115 students at baseline (Grade 7, 2011), of whom 2149 provided data at follow up (Grade 10, 2014; enrolments in Grades 7 to 10 typically aged 12–16 years; 50% male; 69.0% retention). There were no significant differences between groups at follow-up for three mental health outcomes: total SDQ, internalising problems, and prosocial behaviour. A small statistically significant difference in favour of the control group was found for externalising problems. Findings highlight the continued difficulties in developing effective, school-based prevention programs for mental health problems in adolescents
Chloride diffusion and acid resistance of concrete containing zeolite and tuff as partial replacements of cement and sand
No full textIn this paper, the properties of concrete containing zeolite and tuff as partial replacements of cement and sand were studied. The compressive strength, water absorption, chloride ion diffusion and resistance to acid environments of concretes made with zeolite at proportions of 10% and 15% of binder and tuff at ratios of 5%, 10% and 15% of fine aggregate were investigated. The results showed that the compressive strength of samples with zeolite and tuff increased considerably. In general, the concrete strength increased with increasing tuff content, and the strength was further improved when cement was replaced by zeolite. According to the water absorption results, specimens with zeolite showed the lowest water absorption values. With the incorporation of tuff and zeolite, the chloride resistance of specimens was enhanced significantly. In terms of the water absorption and chloride diffusion results, the most favorable replacement of cement and sand was 10% zeolite and 15% tuff, respectively. However, the resistance to acid attack reduced due to the absorbing characteristic and calcareous nature of the tuff
Graph labeling techniques
No full textWe give some background to the labeling schemes like graceful, harmonious, magic, antimagic and irregular total labelings. Followed by this we give some preliminary results and open problems in these schemes. We will introduce a new branch of irregular total labeling, irregular reflexive labeling. This new labeling technique has few variations on vertices labels from irregular total labeling. They are, 1) The vertices labels are non negative even integers. 2) The vertex label 0 is permissible, representing the vertex without loop. The vertex (edge) irregular reflexive labeling is a total irregular labeling with above conditions on vertices labeling such that the vertices (edges) weights are distinct. The idea is to use minimum possible labels for vertices (edges) and thus keeping the reflexive vertex (edge) strength as low as possible. We believe that this new technique is closer in concept to the original irregular labeling as proposed by Chartrand et al., since the vertex labels are also being used to represent edges(loops). Again the objective is to minimize the total strength by using the smallest vertices/edges labels. We will give edge and vertex irregular reflexive strengths for many graphs such as paths, cycles, stars, complete graphs, prisms, wheels, baskets, friendship graphs, join of graphs and generalised friendship graphs and present labeling techniques for these graphs. We also describe edge covering, H-edge covering, H-magic and H-antimagic graphs and prove some theorems based on these concepts. Many results have been established for construction of H-antimagic labelings of graphs. We will use the partitions of a set of integers with determined differences, the upper bound of the difference d if the graph GH is super (a,d)-H-antimagic, establishment of connection between H-antimagic labelings and edge-antimagic total labelings. We have also posed some open problems. Finally we address why study of graph labeling is important by explaining some applications of graph labeling and give some open problems and conjectures