989 resultados para Environments for zonal cartilage tissue engineerin
Resumo:
This project examines procurement of creative services in a bureaucratic setting and proposes alternative procedures that better negotiate the tensions between creative and bureaucratised ways of working. The outcome is a project procurement strategy called 'Creative Practice Enabled Procurement' and a prototype industry toolkit 'It's Not Shopping! A Guide to Purchasing Innovation and Creativity'. The research is of benefit to managers and creative practitioners, especially those working in interpretive settings. The goal is to propagate better forms of creative procurement across government and private sectors by providing an evidence-based case for improved, practical alternatives.
Resumo:
This project has determined angiogenic and anti-angiogenic factors in osteoarthritis cartilage. The work has expanded our knowledge and understanding of the importance of anti-angiogenic factors in maintaining cartilage homeostasis. This study also tested the concept of topical application of anti-angiogenic treatment strategy for osteoarthritis.
Resumo:
The visual characteristics of urban environments have been changing dramatically with the growth of cities around the world. Protection and enhancement of landscape character in urban environments have been one of the challenges for policy makers in addressing sustainable urban growth. Visual openness and enclosure in urban environments are important attributes in perception of visual space which affect the human interaction with physical space and which can be often modified by new developments. Measuring visual openness in urban areas results in more accurate, reliable, and systematic approach to manage and control visual qualities in growing cities. Recent advances in techniques in geographic information systems (GIS) and survey systems make it feasible to measure and quantify this attribute with a high degree of realism and precision. Previous studies in this field do not take full advantage of these improvements. This paper proposes a method to measure the visual openness and enclosure in a changing urban landscape in Australia, on the Gold Coast, by using the improved functionality in GIS. Using this method, visual openness is calculated and described for all publicly accessible areas in the selected study area. A final map is produced which shows the areas with highest visual openness and visibility to natural landscape resources. The output of this research can be used by planners and decision-makers in managing and controlling views in complex urban landscapes. Also, depending on the availability of GIS data, this method can be applied to any region including non-urban landscapes to help planners and policy-makers manage views and visual qualities.
Resumo:
Background: In the spondyloarthropathies, the underlying molecular and cellular pathways driving disease are poorly understood. By undertaking a study in knee synovial biopsies from spondyloarthropathy (SpA) and ankylosing spondylitis (AS) patients we aimed to elucidate dysregulated genes and pathways. Methods RNA was extracted from six SpA, two AS, three osteoarthritis (OA) and four normal control knee synovial biopsies. Whole genome expression profiling was undertaken using the Illumina DASL system, which assays 24000 cDNA probes. Differentially expressed candidate genes were then validated using quantitative PCR and immunohistochemistry. Results: Four hundred and sixteen differentially expressed genes were identified that clearly delineated between AS/SpA and control groups. Pathway analysis showed altered gene-expression in oxidoreductase activity, B-cell associated, matrix catabolic, and metabolic pathways. Altered «myogene» profiling was also identified. The inflammatory mediator, MMP3, was strongly upregulated (5-fold) in AS/SpA samples and the Wnt pathway inhibitors DKK3 (2.7-fold) and Kremen1 (1.5-fold) were downregulated. Conclusions: Altered expression profiling in SpA and AS samples demonstrates that disease pathogenesis is associated with both systemic inflammation as well as local tissue alterations that may underlie tissue damaging modelling and remodelling outcomes. This supports the hypothesis that initial systemic inflammation in spondyloarthropathies transfers to and persists in the local joint environment, and might subsequently mediate changes in genes directly involved in the destructive tissue remodelling.
Resumo:
Purpose The present study aimed to review the effect of dehydration during Ramadan fasting on the health and ocular parameters leading to changes in eye function. Methods Articles included in the study were taken from PubMed, Ovid, Web of Science and Google Scholar up to 2014. Related articles were also obtained from scientific journals on fasting and vision system. Results Dehydration and nutrition changes in Ramadan cause an increase in tear osmolarity, ocular aberration, anterior chamber depth, IOL measurement, central corneal thickness, retinal and choroidal thicknesses, and also a decrease in IOP, tear secretion, and vitreous thickness. Conclusion Much research related to the effect of dehydration on ocular parameters during Ramadan fasting exists. The findings reveal association with significant changes on ocular parameters. Thus, it seems requisite to have a comprehensive study on "fasting and ocular parameters”, which will be helpful in making decisions and giving plan to the patients.
Resumo:
BACKGROUND Experimental learning, traditionally conducted in on-campus laboratory venues, is the cornerstone of science and engineering education. In order to ensure that engineering graduates are exposed to ‘real-world’ situations and attain the necessary professional skill-sets, as mandated by course accreditation bodies such as Engineers Australia, face-to-face laboratory experimentation with real equipment has been an integral component of traditional engineering education. The online delivery of engineering coursework endeavours to mimic this with remote and simulated laboratory experimentation. To satisfy student and accreditation requirements, the common practice has been to offer equivalent remote and/or simulated laboratory experiments in lieu of the ones delivered, face-to face, on campus. The current implementations of both remote and simulated laboratories tend to be specified with a focus on technical characteristics, instead of pedagogical requirements. This work attempts to redress this situation by developing a framework for the investigation of the suitability of different experimental educational environments to deliver quality teaching and learning. PURPOSE For the tertiary education sector involved with technical or scientific training, a research framework capable of assessing the affordances of laboratory venues is an important aid during the planning, designing and evaluating stages of face-to-face and online (or cyber) environments that facilitate student experimentation. Providing quality experimental learning venues has been identified as one of the distance-education providers’ greatest challenges. DESIGN/METHOD The investigation draws on the expertise of staff at three Australian universities: Swinburne University of Technology (SUT), Curtin University (Curtin) and Queensland University of Technology (QUT). The aim was to analyse video recorded data, in order to identify the occurrences of kikan-shido (a Japanese term meaning ‘between desks instruction’ and over-the-shoulder learning and teaching (OTST/L) events, thereby ascertaining the pedagogical affordances in face-to-face laboratories. RESULTS These will be disseminated at a Master Class presentation at this conference. DISCUSSION Kikan-shido occurrences did reflect on the affordances of the venue. Unlike with other data collection methods, video recorded data and its analysis is repeatable. Participant bias is minimised or even eradicated and researcher bias tempered by enabling re-coding by others. CONCLUSIONS Framework facilitates the identification of experiential face-to-face learning venue affordances. Investigation will continue with on-line venues.
Resumo:
AIM: This study investigated the ability of an osteoconductive biphasic scaffold to simultaneously regenerate alveolar bone, periodontal ligament and cementum. MATERIALS AND METHODS: A biphasic scaffold was built by attaching a fused deposition modelled bone compartment to a melt electrospun periodontal compartment. The bone compartment was coated with a calcium phosphate (CaP) layer for increasing osteoconductivity, seeded with osteoblasts and cultured in vitro for 6 weeks. The resulting constructs were then complemented with the placement of PDL cell sheets on the periodontal compartment, attached to a dentin block and subcutaneously implanted into athymic rats for 8 weeks. Scanning electron microscopy, X-ray diffraction, alkaline phosphatase and DNA content quantification, confocal laser microscopy, micro computerized tomography and histological analysis were employed to evaluate the scaffold's performance. RESULTS: The in vitro study showed that alkaline phosphatase activity was significantly increased in the CaP-coated samples and they also displayed enhanced mineralization. In the in vivo study, significantly more bone formation was observed in the coated scaffolds. Histological analysis revealed that the large pore size of the periodontal compartment permitted vascularization of the cell sheets, and periodontal attachment was achieved at the dentin interface. CONCLUSIONS: This work demonstrates that the combination of cell sheet technology together with an osteoconductive biphasic scaffold could be utilized to address the limitations of current periodontal regeneration techniques.
Resumo:
Mammographic density (MD) is a strong risk factor for breast cancer. It is altered by exogenous endocrine treatments, including hormone replacement therapy and Tamoxifen. Such agents also modify breast cancer (BC) risk. However, the biomolecular basis of how systemic endocrine therapy modifies MD and MD-associated BC risk is poorly understood. This study aims to determine whether our xenograft biochamber model can be used to study the effectiveness of therapies aimed at modulating MD, by examine the effects of Tamoxifen and oestrogen on histologic and radiographic changes in high and low MD tissues maintained within the biochamber model. High and low MD human tissues were precisely sampled under radiographic guidance from prophylactic mastectomy fresh specimens of high-risk women, then inserted into separate vascularized murine biochambers. The murine hosts were concurrently implanted with Tamoxifen, oestrogen or placebo pellets, and the high and low MD biochamber tissues maintained in the murine host environment for 3 months, before the high and low MD biochamber tissues were harvested for histologic and radiographic analyses. The radiographic density of high MD tissue maintained in murine biochambers was decreased in Tamoxifen-treated mice compared to oestrogen-treated mice (p = 0.02). Tamoxifen treatment of high MD tissue in SCID mice led to a decrease in stromal (p = 0.009), and an increase in adipose (p = 0.023) percent areas, compared to placebo-treated mice. No histologic or radiographic differences were observed in low MD biochamber tissue with any treatment. High MD biochamber tissues maintained in mice implanted with Tamoxifen, oestrogen or placebo pellets had dynamic and measurable histologic compositional and radiographic changes. This further validates the dynamic nature of the MD xenograft model, and suggests the biochamber model may be useful for assessing the underlying molecular pathways of Tamoxifen-reduced MD, and in testing of other pharmacologic interventions in a preclinical model of high MD.
Resumo:
Organ-specific immunity is a feature of many infectious diseases, including visceral leishmaniasis caused by Leishmania donovani. Experimental visceral leishmaniasis in genetically susceptible mice is characterized by an acute, resolving infection in the liver and chronic infection in the spleen. CD4+ T cell responses are critical for the establishment and maintenance of hepatic immunity in this disease model, but their role in chronically infected spleens remains unclear. In this study, we show that dendritic cells are critical for CD4+ T cell activation and expansion in all tissue sites examined. We found that FTY720-mediated blockade of T cell trafficking early in infection prevented Ag-specific CD4+ T cells from appearing in lymph nodes, but not the spleen and liver, suggesting that early CD4+ T cell priming does not occur in liver-draining lymph nodes. Extended treatment with FTY720 over the first month of infection increased parasite burdens, although this associated with blockade of lymphocyte egress from secondary lymphoid tissue, as well as with more generalized splenic lymphopenia. Importantly, we demonstrate that CD4+ T cells are required for the establishment and maintenance of antiparasitic immunity in the liver, as well as for immune surveillance and suppression of parasite outgrowth in chronically infected spleens. Finally, although early CD4+ T cell priming appeared to occur most effectively in the spleen, we unexpectedly revealed that protective CD4+ T cell-mediated hepatic immunity could be generated in the complete absence of all secondary lymphoid tissues.
Resumo:
For a successful clinical outcome, periodontal regeneration requires the coordinated response of multiple soft and hard tissues (periodontal ligament, gingiva, cementum, and bone) during the wound-healing process. Tissue-engineered constructs for regeneration of the periodontium must be of a complex 3-dimensional shape and adequate size and demonstrate biomechanical stability over time. A critical requirement is the ability to promote the formation of functional periodontal attachment between regenerated alveolar bone, and newly formed cementum on the root surface. This review outlines the current advances in multiphasic scaffold fabrication and how these scaffolds can be combined with cell- and growth factor-based approaches to form tissue-engineered constructs capable of recapitulating the complex temporal and spatial wound-healing events that will lead to predictable periodontal regeneration. This can be achieved through a variety of approaches, with promising strategies characterized by the use of scaffolds that can deliver and stabilize cells capable of cementogenesis onto the root surface, provide biomechanical cues that encourage perpendicular alignment of periodontal fibers to the root surface, and provide osteogenic cues and appropriate space to facilitate bone regeneration. Progress on the development of multiphasic constructs for periodontal tissue engineering is in the early stages of development, and these constructs need to be tested in large animal models and, ultimately, human clinical trials.
Resumo:
In vitro pre-vascularization is one of the main vascularization strategies in the tissue engineering field. Culturing cells within a tissue-engineered construct (TEC) prior to implantation provides researchers with a greater degree of control over the fate of the cells. However, balancing the diverse range of different cell culture parameters in vitro is seldom easy and in most cases, especially in highly vascularized tissues, more than one cell type will reside within the cell culture system. Culturing multiple cell types in the same construct presents its own unique challenges and pitfalls. The following review examines endothelial-driven vascularization and evaluates the direct and indirect role other cell types have in vessel and capillary formation. The article then analyses the different parameters researchers can modulate in a co-culture system in order to design optimal tissue-engineered constructs to match desired clinical applications.
Authorisation management in business process environments: An authorisation model and a policy model
Resumo:
This thesis provides two main contributions. The first one is BP-TRBAC, a unified authorisation model that can support legacy systems as well as business process systems. BP-TRBAC supports specific features that are required by business process environments. BP-TRBAC is designed to be used as an independent enterprise-wide authorisation model, rather than having it as part of the workflow system. It is designed to be the main authorisation model for an organisation. The second contribution is BP-XACML, an authorisation policy language that is designed to represent BPM authorisation policies for business processes. The contribution also includes a policy model for BP-XACML. Using BP-TRBAC as an authorisation model together with BP-XACML as an authorisation policy language will allow an organisation to manage and control authorisation requests from workflow systems and other legacy systems.
Resumo:
TERMINAL EAR1-like (TEL) genes encode putative RNA-binding proteins only found in land plants. Previous studies suggested that they may regulate tissue and organ initiation in Poaceae. Two TEL genes were identified in both Populus trichocarpa and the hybrid aspen Populus tremula × P. alba, named, respectively, PoptrTEL1-2 and PtaTEL1-2. The analysis of the organisation around the PoptrTEL genes in the P. trichocarpa genome and the estimation of the synonymous substitution rate for PtaTEL1-2 genes indicate that the paralogous link between these two Populus TEL genes probably results from the Salicoid large-scale gene-duplication event. Phylogenetic analyses confirmed their orthology link with the other TEL genes. The expression pattern of both PtaTEL genes appeared to be restricted to the mother cells of the plant body: leaf founder cells, leaf primordia, axillary buds and root differentiating tissues, as well as to mother cells of vascular tissues. Most interestingly, PtaTEL1-2 transcripts were found in differentiating cells of secondary xylem and phloem, but probably not in the cambium itself. Taken together, these results indicate specific expression of the TEL genes in differentiating cells controlling tissue and organ development in Populus (and other Angiosperm species).
Resumo:
Finite element analysis (FEA) models of uniaxial loading of pumpkin peel and flesh tissues were developed and validated using experimental results. The tensile model was developed for both linear elastic and plastic material models, the compression model was develop d only with the plastic material model. The outcomes of force versus time curves obtained from FEA models followed similar pattern to the experimental curves however the curve resulted with linear elastic material properties had a higher difference with the experimental curves. The values of predicted forces were determined and compared with the experimental curve. An error indicator was introduced and computed for each case and compared. Additionally Root Mean Square Error (RMSE) values were also calculated for each model and compared. The results of modelling were used to develop material model for peel and flesh tissues in FEA modelling of mechanical peeling of tough skinned vegetables.
Resumo:
Advances in tissue-engineering have resulted in a versatile tool-box to specifically design a tailored microenvironment for hematopoietic stem cells (HSCs) in order to study diseases that develop within this setting. However, most current in vivo models fail to recapitulate the biological processes seen in humans. Here we describe a highly reproducible method to engineer humanized bone constructs that are able to recapitulate the morphological features and biological functions of the HSC niches. Ectopic implantation of biodegradable composite scaffolds cultured for 4 weeks with human mesenchymal progenitor cells and loaded with rhBMP-7 resulted in the development of a chimeric bone organ including a large number of human mesenchymal cells which were shown to be metabolically active and capable of establishing a humanized microenvironment supportive of the homing and maintenance of human HSCs. A syngeneic mouse-to-mouse transplantation assay was used to prove the functionality of the tissue-engineered ossicles. We predict that the ability to tissue engineer a morphologically intact and functional large-volume bone organ with a humanized bone marrow compartment will help to further elucidate physiological or pathological interactions between human HSCs and their native niches.