990 resultados para Differentiation Strategies


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This presenation is part of the UDIA (Qld) Property Development Essentials program, which is a two-day introductory course designed for new entrants to the property industry. The course provides practical advice and direction for those looking to take the first steps into the development industry. This presentation identifies economic factors and their influence on land acquisitions, as well as providing an understanding the property development and business cycles and their impacts on acquisition strategies (long v. short term projects)

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One of the main aims in artificial intelligent system is to develop robust and efficient optimisation methods for Multi-Objective (MO) and Multidisciplinary Design (MDO) design problems. The paper investigates two different optimisation techniques for multi-objective design optimisation problems. The first optimisation method is a Non-Dominated Sorting Genetic Algorithm II (NSGA-II). The second method combines the concepts of Nash-equilibrium and Pareto optimality with Multi-Objective Evolutionary Algorithms (MOEAs) which is denoted as Hybrid-Game. Numerical results from the two approaches are compared in terms of the quality of model and computational expense. The benefit of using the distributed hybrid game methodology for multi-objective design problems is demonstrated.

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Articular cartilage exhibits limited intrinsic regenerative capacity and focal tissue defects can lead to the development of osteoarthritis (OA), a painful and debilitating loss of cartilage tissue. In Australia, 1.4 million people are affected by OA and its prevalence is increasing in line with current demographics. As treatment options are limited, new therapeutic approaches are being investigated including biological resurfacing of joints with tissue-engineered cartilage. Despite some progress in the field, major challenges remain to be addressed for large scale clinical success. For example, large numbers of chondrogenic cells are required for cartilage formation, but chondrocytes lose their chondrogenic phenotype (dedifferentiate) during in vitro propagation. Additionally, the zonal organization of articular cartilage is critical for normal cartilage function, but development of zonal structure has been largely neglected in cartilage repair strategies. Therefore, we hypothesised that culture conditions for freshly isolated human articular chondrocytes from non-OA and OA sources can be improved by employing microcarrier cultures and a reduced oxygen environment and that oxygen is a critical factor in the maintenance of the zonal chondrocyte phenotype. Microcarriers have successfully been used to cultivate bovine chondrocytes, and offer a potential alternative for clinical expansion of human chondrocytes. We hypothesised that improved yields can be achieved by propagating human chondrocytes on microcarriers. We found that cells on microcarriers acquired a flattened, polygonal morphology and initially proliferated faster than monolayercultivated cells. However, microcarrier cultivation over four weeks did not improve growth rates or the chondrogenic potential of non-OA and OA human articular chondrocytes over conventional monolayer cultivation. Based on these observations, we aimed to optimise culture conditions by modifying oxygen tension, to more closely reflect the in vivo environment. We found that propagation at 5% oxygen tension (moderate hypoxia) did not improve proliferation or redifferentiation capacity of human osteoarthritic chondrocytes. Moderate hypoxia increased the expression of chondrogenic markers during redifferentiation. However, osteoarthritic chondrocytes cultivated on microcarriers exhibited lower expression levels of chondrogenic surface marker proteins and had at best equivalent redifferentiation capacities compared to monolayer-cultured cells. This suggests that monolayer culture with multiple passaging potentially selects for a subpopulation of cells with higher differentiation capacity, which are otherwise rare in osteoarthritic, aged cartilage. However, fibroblastic proteins were found to be highly expressed in all cultures of human osteoarthritic chondrocytes indicating the presence of a high proportion of dedifferentiated, senescent cells with a chondrocytic phenotype that was not rescued by moderate hypoxia. The different zones of cartilage support chondrocyte subpopulations, which exhibit characteristic protein expression and experience varying oxygen tensions. We, therefore, hypothesised that oxygen tension affects the zonal marker expression of human articular chondrocytes isolated from the different cartilage layers. We found that zonal chondrocytes maintained these phenotypic differences during in vitro cultivation. Low oxygen environments favoured the expression of the zonal marker proteoglycan 4 in superficial cells, most likely through the promotion of chondrogenesis. The putative zonal markers clusterin and cartilage intermediate layer protein were found to be expressed by all subpopulations of human osteoarthritic chondrocytes ex vivo and, thus, may not be reliable predictors of in vitro stratification using these clinically relevant cells. The findings in this thesis underline the importance of considering low oxygen conditions and zonal stratification when creating native-like cartilaginous constructs. We have not yet found the right cues to successfully cultivate clinically-relevant human osteoarthritic chondrocytes in vitro. A more thorough understanding of chondrocyte biology and the processes of chondrogenesis are required to ensure the clinical success of cartilage tissue engineering.

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Aim: Worldwide, injury is the leading cause of death and disability for young people. Injuries among young people are commonly associated with risk taking behaviour, including violence and transport risks, which often occur in the context of alcohol use. The school environment has been identified as having a significant role in shaping adolescent behaviour. In particular, school connectedness, the degree to which adolescents feel that they belong and are accepted at school, has been shown to be an important protective factor. Strategies for increasing school connectedness may therefore be effective in reducing risk taking and associated injury. Prior to developing connectedness strategies, it is important to understand the perspectives of those in the school regarding the construct and how it is realised in the school context. The aim of this research was to understand teachers’ perspectives of school connectedness, the strategies they employ to connect with students, and their perceptions of school connectedness as a strategy for risk taking and injury prevention. Method: In depth interviews of approximately 45 minutes duration were conducted with 13 Health and PE teachers and support staff from 2 high schools in Southeast Queensland, Australia. Additionally, 6 focus group workshop discussions were held with 35 Education department employees (5-6 per group), including teachers from 15 Southeast Queensland high schools. Results: Participants were found to place strong importance on the development of connectedness among students, including those at risk for problem behaviour. Strategies used to promote connectedness included building trust, taking an interest in each student and being available to talk to, and finding something positive for students to succeed at. Teachers identified strategies as being related to decreased risk taking behavior. Teacher training on school connectedness was perceived as an important and useful inclusion in a school based injury prevention program. Conclusions: The established link between increased school connectedness and decreased problem behaviour has implications for school based strategies designed to decrease adolescent risk taking behaviour and associated injury. Targeting school connectedness as a point of intervention, in conjunction with individual attitude and behaviour change programs, may be an effective injury prevention strategy.

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The impact of government policy can become a strong enabler for the use of e-portfolios to support learning and employability. E-portfolio policy and practice seeks to draw together the different elements of integrated education and learning, graduate attributes, employability skills, professional competencies and lifelong learning, ultimately to support an engaged and productive workforce. Drawing on and updating the research findings from a nationwide research study conducted as part of the Australian ePortfolio Project, the present chapter discusses two important areas of the e-portfolio environment, government policy and academic policy. The focus is on those jurisdictions where government and academic policy issues have had a significant impact on e-portfolio practice, such as the European Union, the Netherlands, Scandinavian countries and the United Kingdom, as well as in Australia and New Zealand. These jurisdictions are of interest as government policy discussions are currently focusing on the need for closer integration between the different education and employment sectors. Finally, issues to be considered as well as strategies for driving policy decision making are presented.

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The pore architecture of scaffolds is known to play a critical role in tissue engineering as it provides the vital framework for seeded cells to organize into a functioning tissue. In this report we have investigated the effects of different concentrations of silk fibroin protein on three-dimensional (3D) scaffold pore microstructure. Four pore size ranges of silk fibroin scaffolds were made by the freeze drying technique, with the pore sizes ranging from 50 to 300 lm. The pore sizes of the scaffolds decreased as the concentration of fibroin protein increased. Human bone marrow mesenchymal stromal cells (BMSC) transfected with the BMP7 gene were cultured in these scaffolds. A cell viability colorimetric assay, alkaline phosphatase assay and reverse transcription-polymerase chain reaction were performed to analyze the effect of pore size on cell growth, the secretion of extracellular matrix (ECM) and osteogenic differentiation. Cell migration in 3D scaffolds was confirmed by confocal microscopy. Calvarial defects in SCID mice were used to determine the bone forming ability of the silk fibroin scaffolds incorporating BMSC expressing BMP7. The results showed that BMSC expressing BMP7 preferred a pore size between 100 and 300 lm in silk fibroin protein fabricated scaffolds, with better cell proliferation and ECM production. Furthermore, in vivo transplantation of the silk fibroin scaffolds combined with BMSC expressing BMP7 induced new bone formation. This study has shown that an optimized pore architecture of silk fibroin scaffolds can modulate the bioactivity of BMP7-transfected BMSC in bone formation.

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With the increasing complexity of modern day threats and the growing sophistication of interlinked and interdependent operating environments, Business Continuity Management (BCM) has emerged as a new discipline, offering a strategic approach to safeguarding organisational functions. Of significant interest is the application of BCM frameworks and strategies within critical infrastructure, and in particular the aviation industry. Given the increased focus on security and safety for critical infrastructures, research into the adoption of BCM principles within an airport environment provides valuable management outcomes and research into a previously neglected area of inquisition. This research has used a single case study methodology to identify possible impediments to BCM adoption and implementation by the Brisbane Airport Corporation (BAC). It has identified a number of misalignments between the required breadth of focus for a BCM program, identified differing views on specific roles and responsibilities required during a major disruptive event and illustrated the complexities of the Brisbane Airport which impede the understanding and implementation of effective Business Continuity Management Strategies.

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This thesis is a work of creative practice-led research comprising two components. The first component is a speculative thriller novel, entitled Diamond Eyes. (Contracted for publication in 2009 by Harper Collins: Voyager as the first in a trilogy, under the name AA Bell.) The second component is an exegesis exploring the notion of re-visioning a novel. Re-visioning, not to be confused with revision, refers to advance editing strategies required when the original vision of a novel changes during development.