225 resultados para Transition form factors


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Melanoma is the most aggressive form of skin cancer. Five-year survival rates for patients with metastatic melanoma are less than 10%, with a median survival of 6 to 9 months. Despite a number of clinical trials for metastatic melanoma, the treatment options for patients are limited. Palliation is often the main goal of treatment. This constructivist grounded theory study is seeking to examine how people with metastatic melanoma negotiate the transition to palliative care. The method of sampling is purposive and data have been generated through semi-structured interviews with those with metastatic melanoma and partners. Open, focused and theoretical coding of data from 13 interviews conducted to date has produced analytical concepts that reflect how the transition is negotiated. These concepts depict ways in which individuals interact with a fragmented health care system and how meanings are constructed around the rapid progression of the disease and uncertain treatment decisions. The preliminary findings reported upon here are being further explored with a larger sample. The findings to date highlight the need for improved coordination of services for those living with metastatic melanoma, and improved support for individuals dealing with uncertainty.

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With unpredictable workloads and a need for a multitude of specialized skills, many main contractors rely heavily on subcontracting to reduce their risks (Bresnen et al., 1985; Beardsworth et al., 1988). This is especially the case In Hong Kong, where the average direct labour content accounts for only around 1% of the total contract sum (Lai, 1987). Extensive usage of subcontracting is also reported in many other countries, including the UK (Gray and Flanagan, 1989) and Japan (Bennett et al., 1987). In addition, and depending upon the scale and complexity of works, it is not uncommon for subcontractors to further sublet their works to lower tier(s) subcontractors. Richter and Mitchell (1982) argued that main contractors can obtain a higher profit margin by reducing their performance costs by subcontracting work to those who have the necessary resources to perform the work more efficiently and economically. Subcontracting is also used strategically to allow firms to employ a minimum work force under fluctuating demand (Usdiken and Sözen, 1985). Through subcontracting, the risks of main contractors are also reduced, as errors in estimating or additional costs caused by delays or extra labour requirements can be absorbed by the subcontractors involved (Woon and Ofori, 2000). Despite these benefits, the quality of work can suffer when incapable or inexperienced subcontractors are employed. Additional problems also exist in the form of bid shopping, unclear accountability, and high fragmentation (Palaneeswaran et al., 2002). A recent CIB TG 23 International Conference, October 2003, Hong Kong report produced by the Hong Kong Construction Industry Review Committee (CIRC) points to development of a framework to help distinguish between capable and incapable subcontractors (Tang, 2001). This paper describes research aims at identifying and prioritising criteria for use in such a framework.

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For the past decade, an attempt has been made by many research groups to define the roles of the growing number of Bcl-2 gene family proteins in the apoptotic process. The Bcl-2 family consists of pro-apoptotic (or cell death) and anti-apoptotic (or cell survival) genes and it is the balance in expression between these gene lineages that may determine the death or survival of a cell. The majority of studies have analysed the role/s of the Bcl-2 genes in cancer development. Equally important is their role in normal tissue development, homeostasis and non-cancer disease states. Bcl-2 is crucial for normal development in the kidney, with a deficiency in Bcl-2 producing such malformation that renal failure and death result. As a corollary, its role in renal disease states in the adult has been sought. Ischaemia is one of the most common causes of both acute and chronic renal failure. The section of the kidney that is most susceptible to ischaemic damage is the outer zone of the outer medulla. Within this zone the proximal tubules are most sensitive and often die by necrosis or desquamate. In the distal nephron, apoptosis is the more common form of cell death. Recent results from our laboratory have indicated that ischaemia-induced acute renal failure is associated with up-regulation of two anti-apoptotic Bcl-2 proteins (Bcl-2 and Bcl-XL) in the damaged distal tubule and occasional up-regulation of Bax in the proximal tubule. The distal tubule is a known reservoir for several growth factors important to renal growth and repair, such as insulin-like growth factor-1 (IGF-1) and epidermal growth factor (EGF). One of the likely possibilities for the anti-cell death action of the Bcl-2 genes is that the protected distal cells may be able to produce growth factors that have a further reparative or protective role via an autocrine mechanism in the distal segment and a paracrine mechanism in the proximal cells. Both EGF and IGF-1 are also up-regulated in the surviving distal tubules and are detected in the surviving proximal tubules, where these growth factors are not usually synthesized. As a result, we have been using in vitro methods to test: (i) the relative sensitivities of renal distal and proximal epithelial cell populations to injury caused by mechanisms known to act in ischaemia-reperfusion; (ii) whether a Bcl-2 anti-apoptotic mechanism acts in these cells; and (iii) whether an autocrine and/or paracrine growth factor mechanism is initiated. The following review discusses the background to these studies as well as some of our preliminary results.

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Enormous progress has been made towards understanding the role of specific factors in the process of epithelial-mesenchymal transition (EMT); however, the complex underlying pathways and the transient nature of the transition continues to present significant challenges. Targeting tumour cell plasticity underpinning EMT is an attractive strategy to combat metastasis. Global gene expression profiling and high-content analyses are among the strategies employed to identify novel EMT regulators. In this review, we highlight several approaches to systematically interrogate key pathways involved in EMT, with particular emphasis on the features of multiparametric, high-content imaging screening strategies that lend themselves to the systematic discovery of highly significant modulators of tumour cell plasticity.

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TCNQ·− radical anions (TCNQ = 7,7,8,8,-tetracyanoquinodimethane) form a wide range of semiconducting coordination polymers when coordinated to transition metals. Some such as CuTCNQ and AgTCNQ exhibit molecular switching and memory storage properties; others have intriguing magnetic properties and for example may behave as molecular magnets at low temperature. In this review, the electro- and photo-chemical synthesis and characterization of this important class of material is reviewed. In particular, the electrochemistry and the redox properties of TCNQ derivatives of coordination polymers based on Cu, Ag, Mn, Fe, Co, Ni, Zn and Cd transition metals are surveyed, with an emphasis on the mechanistic aspects of their electrochemical formation via nucleation–growth processes. Given that TCNQ is an extremely good electron acceptor, readily forming TCNQ•− and TCNQ2-, electrochemical reduction of TCNQ in the presence of a transition metal ion provides an ideal method for synthesis of metal-TCNQ materials by electrocrystallization from organic solvents and ionic liquids or solid-solid transformation using TCNQ modified electrodes from aqueous media containing transition metal electrolytes. The significance of the reversible formal potential (E0f) in these studies is discussed. The coupling of electrocrystallisation on electrode surfaces and microscopic characterization of the electrodeposited materials reveals a wide range of morphologies and phases which strongly influence their properties and applications. Since TCNQ also can be photo-reduced in the presence of suitable electron donors, analogous photochemical approaches to the synthesis of TCNQ-transition metal derivatives are available. The advantages of electrochemical and photochemical methods of synthesis relative to chemical synthesis are outlined.

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Purpose: To investigate the changes occurring in the axial length, choroidal thickness and anterior biometrics of the eye during a 10 minute near task performed in downward gaze. Methods: Twenty young adult subjects (10 emmetropes and 10 myopes) participated in this study. To measure ocular biometrics in downward gaze, an optical biometer was inclined on a custom built, height and tilt adjustable table. Baseline measures were collected after each subject performed a distance primary gaze control task for 10 mins, to provide wash-out period for prior visual tasks before each of three different accommodation/gaze conditions. These other three conditions included a near task (2.5 D) in primary gaze, and a near (2.5 D) and a far (0 D) accommodative task in downward gaze (25°), all for 10 mins duration. Immediately after, and then 5 and 10 mins from the commencement of each trial, measurements of ocular biometrics (e.g. anterior biometrics, axial length, choroidal thickness and retinal thickness) were obtained. Results: Axial length increased with accommodation and was significantly greater for downward gaze with accommodation (mean change ± SD 23 ± 13 µm at 10 mins) compared to primary gaze with accommodation (mean change 8 ± 15 µm at 10 mins) (p < 0.05). A small amount of choroidal thinning was also found during accommodation that was statistically significant in downward gaze (13 ± 14 µm at 10 mins, p < 0.05). Accommodation in downward gaze also caused greater changes in anterior chamber depth and lens thickness compared to accommodation in primary gaze. Conclusion: Axial length, choroidal thickness and anterior eye biometrics change significantly during accommodation in downward gaze as a function of time. These changes appear to be due to the combined influence of biomechanical factors (i.e. extraocular muscle forces, ciliary muscle contraction) associated with near tasks in downward gaze.

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Indigenous Australians are among the most unhealthy populations in the world and yet they reside in a country where the non-Indigenous population enjoys high standards of well-being. Education has been identified as the key mechanism for closing this equity gap. At school commencement many Indigenous children are already at risk of disengagement. This four-year longitudinal study of two Indigenous boys from a socially marginalised community examined key factors affecting transitional trajectories into school. While child characteristics affected level of achievement the critical factors in sustaining positive educational engagement were social support, school practices, inclusion of family and positive expectation.

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Regenerative medicine includes two efficient techniques, namely tissue-engineering and cell-based therapy in order to repair tissue damage efficiently. Most importantly, huge numbers of autologous cells are required to deal these practices. Nevertheless, primary cells, from autologous tissue, grow very slowly while culturing in vitro; moreover, they lose their natural characteristics over prolonged culturing period. Transforming growth factors-beta (TGF-β) is a ubiquitous protein found biologically in its latent form, which prevents it from eliciting a response until conversion to its active form. In active form, TGF-β acts as a proliferative agent in many cell lines of mesenchymal origin in vitro. This article reviews on some of the important activation methods-physiochemical, enzyme-mediated, non-specific protein interaction mediated, and drug-induced- of TGF-β, which may be established as exogenous factors to be used in culturing medium to obtain extensive proliferation of primary cells.

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Located at the intersection of two vulnerable groups in the contemporary labour market, young people who migrate as refugees during adolescence face a unique constellation of opportunities and challenges that shape their employment trajectories. Yet the tendency for research to focus on the early years of refugee settlement means that we have an inadequate understanding the factors that mediate their employment decisions, experiences and outcomes. Based on interviews with 51 young people, this article explores how aspirations, responsibilities, family, education and networks are understood to influence the employment trajectories of adolescent refugee migrants. While this article draws attention to the complex and dynamic range of challenges and constraints that these young people negotiate in the pursuit of satisfying and sustainable employment, what also emerges is an optimistic and determined cohort who, even as they at times unsuccessfully prepare for and navigate the labour market, maintain high hopes for a better life.

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Many commentators argue that domestic food waste is strongly influenced by consumer behaviours. This article reports on a study using mixed-methods to identify key factors responsible for promoting consumer behaviours that lead to domestic food waste through the lens of the Value-Belief-Norm (VBN) theory. Based on the study’s findings, three factors are proposed that cause behaviours that lead to food waste: supply knowledge – does a consumer know what food they have available; location knowledge – does a consumer know where to locate food items, and; food literacy – to what degree do past experience and acquired knowledge impact on a consumer’s food consumption and wastage practices. We analyse the study’s findings in light of a review of literature about consumer food wastage behaviours and in turn, present new insights into consumer behaviour, food waste, and the use of technology to reduce food waste.

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Smart Material Interface (SMI) is the latest generation of user interface that makes use of engineered materials and leverages their special properties. SMIs are capable of changing their physical properties such as shape, size and color, and can be controlled under certain (external) conditions. We provide an example of such an SMI in the form of a prototype of a vacuum cleaner. The prototype uses schematic electrochromic polymer at the suction nozzle of the vacuum cleaner, which changes its color depending on the dust level on a floor. We emphasize on the new affordances and communication language supported by SMIs, which challenges the current metaphors of user interfaces in the field of HCI.

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The field of research of epithelial-mesenchymal transitions, EMT, and its reverse, mesenchymal-epithelial transitions, MET, has expanded very rapidly indeed from its beginnings, heralded by Professor Betty Hay in the 1970s and 1980s. This expansion has involved the realisation that the EMT was not just an interesting phenomenon of early developmental morphogenetic cell behaviour, but bore remarkable resemblance to clinically crucial pathological events in cancer invasion. Not surprisingly, this discipline soon became numerically dominant in the EMT publication field. Simultaneously, the EMT concept has been extended to normal physiological wound healing. Exploration revealed that these resemblances were more than skin deep: the same sets of growth factors, receptors, transcription factors, epigenetic marks and signalling pathways turned up repeatedly in EMTs and METs in a variety of contexts, both pathological and normal. This molecular genetic research in turn uncovered similarities of the EMT signature to that of fibrosis, a set of diseases which is of enormous clinical importance, rivalling that of cancer. Most recently, and more surprisingly, the EMT signature has shown considerable similarity to that found in stem cell and cancer stem cell biology.

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Signals from the tumor microenvironment trigger cancer cells to adopt an invasive phenotype through epithelial-mesenchymal transition (EMT). Relatively little is known regarding key signal transduction pathways that serve as cytosolic bridges between cell surface receptors and nuclear transcription factors to induce EMT. A better understanding of these early EMT events may identify potential targets for the control of metastasis. One rapid intracellular signaling pathway that has not yet been explored during EMT induction is calcium. Here we show that stimuli used to induce EMT produce a transient increase in cytosolic calcium levels in human breast cancer cells. Attenuation of the calcium signal by intracellular calcium chelation significantly reduced epidermal growth factor (EGF)- and hypoxia-induced EMT. Intracellular calcium chelation also inhibited EGF-induced activation of signal transducer and activator of transcription 3 (STAT3), while preserving other signal transduction pathways such as Akt and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. To identify calcium-permeable channels that may regulate EMT induction in breast cancer cells, we performed a targeted siRNA-based screen. We found that transient receptor potential-melastatin-like 7 (TRPM7) channel expression regulated EGF-induced STAT3 phosphorylation and expression of the EMT marker vimentin. Although intracellular calcium chelation almost completely blocked the induction of many EMT markers, including vimentin, Twist and N-cadherin, the effect of TRPM7 silencing was specific for vimentin protein expression and STAT3 phosphorylation. These results indicate that TRPM7 is a partial regulator of EMT in breast cancer cells, and that other calcium-permeable ion channels are also involved in calcium-dependent EMT induction. In summary, this work establishes an important role for the intracellular calcium signal in the induction of EMT in human breast cancer cells. Manipulation of calcium-signaling pathways controlling EMT induction in cancer cells may therefore be an important therapeutic strategy for preventing metastases.

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Epithelial-mesenchymal plasticity in breast carcinoma encompasses the phenotypic spectrum whereby epithelial carcinoma cells within a primary tumor acquire mesenchymal features and re-epithelialize to form a cohesive secondary mass at a metastatic site. Such plasticity has implications in progression of breast carcinoma to metastasis, and will likely influence response to therapy. The transcriptional and epigenetic regulation of molecular and cellular processes that underlie breast cancer and result in characteristic changes in cell behavior can be monitored using an increasing array of marker proteins. Amongst these markers exists the potential for emergent prognostic, predictive and therapeutic targeting.

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Epithelial mesenchymal transition (EMT) has long been associated with breast cancer cell invasiveness and evidence of EMT processes in clinical samples is growing rapidly. Genome-wide transcriptional profiling of increasingly larger numbers of human breast cancer (HBC) cell lines have confirmed the existence of a subgroup of cell lines (termed Basal B/Mesenchymal) with enhanced invasive properties and a predominantly mesenchymal gene expression signature, distinct from subgroups with predominantly luminal (termed Luminal) or mixed basal/luminal (termed Basal A) features (Neve et al Cancer Cell 2006). Studies providing molecular and cellular analyses of EMT features in these cell lines are summarised, and the expression levels of EMT-associated factors in these cell lines are analysed. Recent clinical studies supporting the presence of EMT-like changes in vivo are summarised. Human breast cancer cell lines with mesenchymal properties continue to hold out the promise of directing us towards key mechanisms at play in the metastatic dissemination of breast cancer.