948 resultados para human osteoblast matrix
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Section 14(4) of the Human Fertilisation and Embryology Act 2008 imposes – within the general licensing conditions listed in the Human Fertilisation and Embryology Act 1990 – a prohibition to prevent the selection and implantation of embryos for the purpose of creating a child who will be born with a “serious disability.” This article offers a perspective that demonstrates the problematic nature of the consultation, review, and legislative reform process surrounding s 14(4). The term “serious disability” is not defined within the legislation, but we highlight the fact that s 14(4) was passed with the case of selecting deaf children in mind. We consider some of the literature on the topic of disability and deafness, which, we think, casts some doubt on the view that deafness is a “serious disability.” The main position we advance is that the lack of serious engagement with alternative viewpoints during the legislative process was unsatisfactory. We argue that the contested nature of deafness necessitates a more robust consultation process and a clearer explanation and defence of the normative position that underpins s 14(4).
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This editorial first describes the workshop out of which the present special issue arose. The editors then identify the need for a multidisciplinary collection examining the Human Fertilisation and Embryology Act 2008 from both legal and political perspectives, including the consultation process, campaigning and parliamentary debates leading to its passage, and the concluded legislation and its effects. The editorial provides an overview of the legislative reform process, key legislative changes, and the various contributions to the special issue. Cross-cutting themes include the value of a qualitative, discourse-based approach to research in this area; the need to understand the 2008 Act in historical context; unforeseen practical implications of the legislative provisions; and silences and missed opportunities in the legislation. Finally, a postscript covers the changing landscape of hybrid embryo research since the passage of the Act, and the uncertain future of the Human Fertilisation and Embryology Authority at the time of writing.
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Axial acoustic wave propagation has been widely used in evaluating the mechanical properties of human bone in vivo. However, application of this technique to monitor soft tissues, such as tendon, has received comparatively little scientific attention. Laboratory-based research has established that axial acoustic wave transmission is not only related to the physical properties of equine tendon but is also proportional to tensile load to which it is exposed (Miles et al., 1996; Pourcelot et al., 2005). The reproducibility of the technique for in vivo measurements in human tendon, however, has not been established. The aim of this study was to evaluate the limits of agreement for repeated measures of the speed of sound (SoS) in human Achilles tendon in vivo. Methods: A custom built ultrasound device, consisting of an A-mode 1MHz emitter and two regularly spaced receivers, was used to measure the SoS in the mid-portion of the Achilles tendon in ten healthy males and ten females (mean age: 33.8 years, range 23-56 yrs; height: 1.73±0.08 m; weight: 68.4±15.3 kg). The emitter and receivers were held at fixed positions by a polyethylene frame and maintained in close contact with the skin overlying the tendon by means of elasticated straps. Repeated SoS measurements were taken with the subject prone (non-weightbearing and relaxed Achilles tendon) and during quiet bipedal and unipedal stance. In each instance, the device was detached and repositioned prior to measurement. Results: Limits of agreement for repeated SoS measures during non-weightbearing and bipedal and unipedal stance were ±53, ±28 and ±21 m/s, respectively. The average SoS in the non-weightbearing Achilles tendon was 1804±198 m/s. There was a significant increase in the average SoS during bilateral (2122±135 m/s) (P < 0.05) and unilateral (2221±79 m/s) stance (P < 0.05). Conclusions: Repeated SoS measures in human Achilles tendon were more reliable during stance than under non-weightbearing conditions. These findings are consistent with previous research in equine tendon in which lower variability in SoS was observed with increasing tensile load (Crevier-Denoix et al, 2009). Since the limits of agreement for Achilles tendon SoS are nearly 5% of the changes previously observed during walking and therapeutic heel raise exercises, acoustic wave transmission provides a promising new non-invasive method for determining tendon properties during sports and rehabilitation related activities.
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Introduction: The human patellar tendon is highly adaptive to changes in habitual loading but little is known about its acute mechanical response to exercise. This research evaluated the immediate transverse strain response of the patellar tendon to a bout of resistive quadriceps exercise. Methods: Twelve healthy adult males (mean age 34.0+/-12.1 years, height 1.75+/-0.09 m and weight 76.7+/-12.3 kg) free of knee pain participated in the research. A 10-5 MHz linear-array transducer was used to acquire standardised sagittal sonograms of the right patellar tendon immediately prior to and following 90 repetitions of a double-leg parallel-squat exercise performed against a resistance of 175% bodyweight. Tendon thickness was determined 20-mm distal to the pole of the patellar and transverse Hencky strain was calculated as the natural log of the ratio of post- to pre-exercise tendon thickness and expressed as a percentage. Measures of tendon echotexture (echogenicity and entropy) were also calculated from subsequent gray-scale profiles. Results: Quadriceps exercise resulted in an immediate decrease in patellar tendon thickness (P<.05), equating to a transverse strain of -22.5+/-3.4%, and was accompanied by increased tendon echogenicity (P<.05) and decreased entropy (P<.05). The transverse strain response of the patellar tendon was significantly correlated with both tendon echogenicity (r = -0.58, P<.05) and entropy following exercise (r=0.73, P<.05), while older age was associated with greater entropy of the patellar tendon prior to exercise (r=0.79, P<.05) and a reduced transverse strain response (r=0.61, P<.05) following exercise. Conclusions: This study is the first to show that quadriceps exercise invokes structural alignment and fluid movement within the matrix that are manifest by changes in echotexture and transverse strain in the patellar tendon., (C)2012The American College of Sports Medicine
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Particulate matter research is essential because of the well known significant adverse effects of aerosol particles on human health and the environment. In particular, identification of the origin or sources of particulate matter emissions is of paramount importance in assisting efforts to control and reduce air pollution in the atmosphere. This thesis aims to: identify the sources of particulate matter; compare pollution conditions at urban, rural and roadside receptor sites; combine information about the sources with meteorological conditions at the sites to locate the emission sources; compare sources based on particle size or mass; and ultimately, provide the basis for control and reduction in particulate matter concentrations in the atmosphere. To achieve these objectives, data was obtained from assorted local and international receptor sites over long sampling periods. The samples were analysed using Ion Beam Analysis and Scanning Mobility Particle Sizer methods to measure the particle mass with chemical composition and the particle size distribution, respectively. Advanced data analysis techniques were employed to derive information from large, complex data sets. Multi-Criteria Decision Making (MCDM), a ranking method, drew on data variability to examine the overall trends, and provided the rank ordering of the sites and years that sampling was conducted. Coupled with the receptor model Positive Matrix Factorisation (PMF), the pollution emission sources were identified and meaningful information pertinent to the prioritisation of control and reduction strategies was obtained. This thesis is presented in the thesis by publication format. It includes four refereed papers which together demonstrate a novel combination of data analysis techniques that enabled particulate matter sources to be identified and sampling site/year ranked. The strength of this source identification process was corroborated when the analysis procedure was expanded to encompass multiple receptor sites. Initially applied to identify the contributing sources at roadside and suburban sites in Brisbane, the technique was subsequently applied to three receptor sites (roadside, urban and rural) located in Hong Kong. The comparable results from these international and national sites over several sampling periods indicated similarities in source contributions between receptor site-types, irrespective of global location and suggested the need to apply these methods to air pollution investigations worldwide. Furthermore, an investigation into particle size distribution data was conducted to deduce the sources of aerosol emissions based on particle size and elemental composition. Considering the adverse effects on human health caused by small-sized particles, knowledge of particle size distribution and their elemental composition provides a different perspective on the pollution problem. This thesis clearly illustrates that the application of an innovative combination of advanced data interpretation methods to identify particulate matter sources and rank sampling sites/years provides the basis for the prioritisation of future air pollution control measures. Moreover, this study contributes significantly to knowledge based on chemical composition of airborne particulate matter in Brisbane, Australia and on the identity and plausible locations of the contributing sources. Such novel source apportionment and ranking procedures are ultimately applicable to environmental investigations worldwide.
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Chondrocytes dedifferentiate during ex vivo expansion on 2-dimensional surfaces. Aggregation of the expanded cells into 3-dimensional pellets, in the presence of induction factors, facilitates their redifferentiation and restoration of the chondrogenic phenotype. Typically 1×105–5×105 chondrocytes are aggregated, resulting in “macro” pellets having diameters ranging from 1–2 mm. These macropellets are commonly used to study redifferentiation, and recently macropellets of autologous chondrocytes have been implanted directly into articular cartilage defects to facilitate their repair. However, diffusion of metabolites over the 1–2 mm pellet length-scales is inefficient, resulting in radial tissue heterogeneity. Herein we demonstrate that the aggregation of 2×105 human chondrocytes into micropellets of 166 cells each, rather than into larger single macropellets, enhances chondrogenic redifferentiation. In this study, we describe the development of a cost effective fabrication strategy to manufacture a microwell surface for the large-scale production of micropellets. The thousands of micropellets were manufactured using the microwell platform, which is an array of 360×360 µm microwells cast into polydimethylsiloxane (PDMS), that has been surface modified with an electrostatic multilayer of hyaluronic acid and chitosan to enhance micropellet formation. Such surface modification was essential to prevent chondrocyte spreading on the PDMS. Sulfated glycosaminoglycan (sGAG) production and collagen II gene expression in chondrocyte micropellets increased significantly relative to macropellet controls, and redifferentiation was enhanced in both macro and micropellets with the provision of a hypoxic atmosphere (2% O2). Once micropellet formation had been optimized, we demonstrated that micropellets could be assembled into larger cartilage tissues. Our results indicate that micropellet amalgamation efficiency is inversely related to the time cultured as discreet microtissues. In summary, we describe a micropellet production platform that represents an efficient tool for studying chondrocyte redifferentiation and demonstrate that the micropellets could be assembled into larger tissues, potentially useful in cartilage defect repair.
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The exchange between the body and architecture walks a fine line between violence and pleasure. It is through the body that the subject engages with the architectural act, not via thought or reason, but through action. The materiality of architecture is the often the catalyst for some intense association; the wall that defines gender or class, the double bolted door that incarcerates, the enclosed privacy of the bedroom to the love affair. Architecture is the physical manifestation of Lefebvre’s inscribed space. It enacts the social and political systems through bodily occupation. Architecture, when tested by the occupation of bodies, anchors ideology in both space and time. The architect’s script can be powerful when rehearsed honestly to the building’s intentions and just as beautiful when rebuked by the act of protest or unfaithful occupation. This research examines this fine line of violence and pleasure in architecture through performance, in the work of Bryony Lavin’s play Stockholm and Revolving Door by Allora & Calzadilla as part of the recent Kaldor Public Art Projects exhibition 13 Rooms in Sydney. The research is underpinned by the work of Architect and theorist, Bernard Tschumi in his two essays, Violence of Architecture and The Pleasure of Architecture. Studying architecture through the lens of performance shifts the focus of examination from pure thought to the body; because architecture is occupied through the body and not the mind.
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Introduction. We develop a sheep thoracic spine interbody fusion model to study the suitability of polycaprolactone-based scaffold and recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within the thoracic spine. The surgical approach is a mini- open thoracotomy with relevance to minimally invasive deformity correction surgery for adolescent idiopathic scoliosis. To date there are no studies examining the use of this biodegradable implant in combination with biologics in a sheep thoracic spine model. Methods. In the present study, six sheep underwent a 3-level (T6/7, T8/9 and T10/11) discectomy with randomly allocated implantation of a different graft substitute at each of the three levels; (i) calcium phosphate (CaP) coated polycaprolactone based scaffold plus 0.54µg rhBMP-2, (ii) CaP coated PCL- based scaffold alone or (iii) autograft (mulched rib head). Fusion was assessed at six months post-surgery. Results. Computed Tomographic scanning demonstrated higher fusion grades in the rhBMP-2 plus PCL- based scaffold group in comparison to either PCL-based scaffold alone or autograft. These results were supported by histological evaluations of the respective groups. Biomechanical testing revealed significantly higher stiffness for the rhBMP-2 plus PCL- based scaffold group in all loading directions in comparison to the other two groups. Conclusions. The results of this study demonstrate that rhBMP-2 plus PCL-based scaffold is a viable bone graft substitute, providing an optimal environment for thoracic interbody spinal fusion in a large animal model.
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Development of hypoxia-mimicking bone tissue engineering scaffolds is of great importance in stimulating angiogenesis for bone regeneration. Dimethyloxallyl glycine (DMOG) is a cell-permeable, competitive inhibitor of hypoxia-inducible factor prolyl hydroxylase (HIF-PH), which can stabilize hypoxia-inducible factor 1α (HIF-1α) expression. The aim of this study was to develop hypoxia-mimicking scaffolds by delivering DMOG in mesoporous bioactive glass (MBG) scaffolds and to investigate whether the delivery of DMOG could induce a hypoxic microenvironment for human bone marrow stromal cells (hBMSC). MBG scaffolds with varied mesoporous structures (e.g. surface area and mesopore volume) were prepared by controlling the contents of mesopore-template agent. The composition, large-pore microstructure and mesoporous properties of MBG scaffolds were characterized. The effect of mesoporous properties on the loading and release of DMOG in MBG scaffolds was investigated. The effects of DMOG delivery on the cell morphology, cell viability, HIF-1α stabilization, vascular endothelial growth factor (VEGF) secretion and bone-related gene expression (alkaline phosphatase, ALP; osteocalcin, OCN; and osteopontin, OPN) of hBMSC in MBG scaffolds were systematically investigated. The results showed that the loading and release of DMOG in MBG scaffolds can be efficiently controlled by regulating their mesoporous properties via the addition of different contents of mesopore-template agent. DMOG delivery in MBG scaffolds had no cytotoxic effect on the viability of hBMSC. DMOG delivery significantly induced HIF-1α stabilization, VEGF secretion and bone-related gene expression of hBMSC in MBG scaffolds in which DMOG counteracted the effect of HIF-PH and stabilized HIF-1α expression under normoxic condition. Furthermore, it was found that MBG scaffolds with slow DMOG release significantly enhanced the expression of bone-related genes more than those with instant DMOG release. The results suggest that the controllable delivery of DMOG in MBG scaffolds can mimic a hypoxic microenvironment, which not only improves the angiogenic capacity of hBMSC, but also enhances their osteogenic differentiation.
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This PhD study has examined the population genetics of the Russian wheat aphid (RWA, Diuraphis noxia), one of the world’s most invasive agricultural pests, throughout its native and introduced global range. Firstly, this study investigated the geographic distribution of genetic diversity within and among RWA populations in western China. Analysis of mitochondrial data from 18 sites provided evidence for the long-term existence and expansion of RWAs in western China. The results refute the hypothesis that RWA is an exotic species only present in China since 1975. The estimated date of RWA expansion throughout western China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. It is concluded that western China represents the limit of the far eastern native range of this species. Analysis of microsatellite data indicated high contemporary gene flow among northern populations in western China, while clear geographic isolation between northern and southern populations was identified across the Tianshan mountain range and extensive desert regions. Secondly, this study analyzed the worldwide pathway of invasion using both microsatellite and endosymbiont genetic data. Individual RWAs were obtained from native populations in Central Asia and the Middle East and invasive populations in Africa and the Americas. Results indicated two pathways of RWA invasion from 1) Syria in the Middle East to North Africa and 2) Turkey to South Africa, Mexico and then North and South America. Very little clone diversity was identified among invasive populations suggesting that a limited founder event occurred together with predominantly asexual reproduction and rapid population expansion. The most likely explanation for the rapid spread (within two years) from South Africa to the New World is by human movement, probably as a result of the transfer of wheat breeding material. Furthermore, the mitochondrial data revealed the presence of a universal haplotype and it is proposed that this haplotype is representative of a wheat associated super-clone that has gained dominance worldwide as a result of the widespread planting of domesticated wheat. Finally, this study examined salivary gland gene diversity to determine whether a functional basis for RWA invasiveness could be identified. Peroxidase DNA sequence data were obtained for a selection of worldwide RWA samples. Results demonstrated that most native populations were polymorphic while invasive populations were monomorphic, supporting previous conclusions relating to demographic founder effects in invasive populations. Purifying selection most likely explains the existence of a universal allele present in Middle Eastern populations, while balancing selection was evident in East Asian populations. Selection acting on the peroxidase gene may provide an allele-dependent advantage linked to the successful establishment of RWAs on wheat, and ultimately their invasion potential. In conclusion, this study is the most comprehensive molecular genetic investigation of RWA population genetics undertaken to date and provides significant insights into the source and pathway of global invasion and the potential existence of a wheat-adapted genotype that has colonised major wheat growing countries worldwide except for Australia. This research has major biosecurity implications for Australia’s grain industry.
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Skin is the largest, and arguably, the most important organ of the body. It is a complex and multi-dimensional tissue, thus making it essentially impossible to fully model in vitro in conventional 2-dimensional culture systems. In view of this, rodents or pigs are utilised to study wound healing therapeutics or to investigate the biological effects of treatments on skin. However, there are many differences between the wound healing processes in rodents compared to humans (contraction vs. re-epithelialisation) and there are also ethical issues associated with animal testing for scientific research. Therefore, the development of skin equivalent (HSE) models from surgical discard human skin has become an important area of research. The studies in this thesis compare, for the first time, native human skin and the epidermogenesis process in a HSE model. The HSE was reported to be a comparable model for human skin in terms of expression and localisation of key epidermal cell markers. This validated HSE model was utilised to study the potential wound healing therapeutic, hyperbaric oxygen (HBO) therapy. There is a significant body of evidence suggesting that lack of cutaneous oxygen results in and potentiates the chronic, non-healing wound environment. Although the evidence is anecdotal, HBO therapy has displayed positive effects on re-oxygenation of chronic wounds and the clinical outcomes suggest that HBO treatment may be beneficial. Therefore, the HSE was subjected to a daily clinical HBO regime and assessed in terms of keratinocyte migration, proliferation, differentiation and epidermal thickening. HBO treatment was observed to increase epidermal thickness, in particular stratum corneum thickening, but it did not alter the expression or localisation of standard epidermal cell markers. In order to elucidate the mechanistic changes occurring in response to HBO treatment in the HSE model, gene microarrays were performed, followed by qRT-PCR of select genes which were differentially regulated in response to HBO treatment. The biological diversity of the HSEs created from individual skin donors, however, overrode the differences in gene expression between treatment groups. Network analysis of functional changes in the HSE model revealed general trends consistent with normal skin growth and maturation. As a more robust and longer term study of these molecular changes, protein localisation and expression was investigated in sections from the HSEs undergoing epidermogenesis in response to HBO treatment. These proteins were CDCP1, Metallothionein, Kallikrein (KLK) 1 and KLK7 and early growth response 1. While the protein expression within the HSE models exposed to HBO treatment were not consistent in all HSEs derived from all skin donors, this is the first study to detect and compare both KLK1 and CDCP1 protein expression in both a HSE model and native human skin. Furthermore, this is the first study to provide such an in depth analysis of the effect of HBO treatment on a HSE model. The data presented in this thesis, demonstrates high levels of variation between individuals and their response to HBO treatment, consistent with the clinical variation that is currently observed.
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Welcome to the Quality assessment matrix. This matrix is designed for highly qualified discipline experts to evaluate their course, major or unit in a systematic manner. The primary purpose of the Quality assessment matrix is to provide a tool that a group of academic staff at universities can collaboratively review the assessment within a course, major or unit annually. The annual review will result in you being read for an external curricula review at any point in time. This tool is designed for use in a workshop format with one, two or more academic staff, and will lead to an action plan for implementation.
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This article analyzes a series of stories and artworks that were produced in a collective biography workshop. It explores Judith Butler’s concept of the heterosexual matrix combined with a Deleuzian theoretical framework. The article begins with an overview of Butler’s concept of the heterosexual matrix and her theorizations on how it might be disrupted. It then suggests how a Deleuzian framework offers other tools for analyzing these ruptures at the micro level of girls’ everyday interactions.
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Benhabib and Spiegel (1994) examine the role of human capital in the development process empirically using a theory-driven specification rather than the standard production function approach. While they find evidence of a positive impact of human capital on income growth, their result is not robust to the inclusion of inequality as an additional covariate. Using an alternate dataset and different measures of inequality, we find robust support for the hypothesis that human capital matters even when we account for the adverse effect of income inequality on growth.