978 resultados para Barrier function
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Purpose – This paper adds to growing research of psychiatric intensive care units (PICU) by recounting descriptions of psychiatric intensive care settings and discusses the perceptions held by nurses of the organisational interfaces, arrangements and provisions of care in these settings. Design/methodology/approach – Data gathered from focus groups held with nurses from two PICUs was used to establish terminology, defining attributes, related concepts, antecedents, values, processes and concepts related to current practices. A literature search was conducted to permit a review of the conceptual arrangements and contemporary understanding of intensive care for people experiencing acute psychiatric illness based on the perspectives held by the nurses from the focus groups. Findings – Dissonance between service needs and the needs and management of individual patients overshadow strategies to implement comprehensive recovery-oriented approaches. Three factors are reported in this paper that influence standards and procedural practice in PICU; organisational structures; physical structures; and subtype nomenclature. Practical implications – Acute inpatient care is an important part of a comprehensive approach to mental health services. Commonly intensive acute care is delivered in specialised wards or units co-located with acute mental health inpatient units mostly known as PICU. Evidence of the most effective treatment and approaches in intensive care settings that support comprehensive recovery for improved outcomes is nascent. Originality/value – Current descriptions from nurses substantiate wide variations in the provisions, design and classifications of psychiatric intensive care. Idiosyncratic and localised conceptions of psychiatric intensive care are not adequately entailing effective treatment and methods in support of recovery principles for improved and comprehensive outcomes. The authors suggest that more concrete descriptions, guidelines, training and policies for provision of intensive psychiatric health care encompassing the perspective of nursing professionals, would reinforce conceptual construction and thus optimum treatments within a comprehensive, recovery-oriented approach to mental health services.
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Road safety barriers are used to redirect traffic at roadside work-zones. When filled with water, these barriers are able to withstand low to moderate impact speeds up to 50kmh-1. Despite this feature, Portable Water-filled barriers (PWFB) face challenges such as large lateral displacements, tearing and breakage during impact; especially at higher speeds. This study explores the use of composite action to enhance the crashworthiness of PWFBs and enable their usage at higher speeds. Initially, energy absorption capability of water in PWFB is investigated. Then, composite action of the PWFB with the introduction of steel frame is considered to evaluate its enhanced impact performance. Findings of the study show that the initial height of the impact must be lower than the free surface level of water in a PWFB in order for the water to provide significant crash energy absorption. In general, an impact of a road barrier with 80% filled is a good estimation. Furthermore, the addition of a composite structure greatly reduces the probability of tearing by decreasing the strain and impact energy transferred to the shell container. This allows the water to remain longer in the barrier to absorb energy via inertial displacements and sloshing response. Information from this research will aid in the design of new generation roadside safety structures aimed to increase safety in modern roadways.
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Alcohol consumption is enmeshed with Australian culture (Palk, 2008) and the use and misuse of alcohol contributes to considerable health and social harms (Barbor et al., 2010; English et al., 1995; Gutjahr, Gmel, & Rehm, 2001; Palk, 2008; Steenkamp, Harrison, & Allsop, 2002). Despite shifts in the way that alcohol is consumed and how it is used, it has been reported that one-third of all alcohol consumed is done so within licensed premises (Lang, Stockwell, Rydon, & Gamble, 1992). Consequently, licensed premises are over-represented as settings in which alcohol-related harms occur. These harms, particularly those related to violence, are associated with particular licensed premises operating in the night-time economy (Briscoe & Donnelly, 2001b; Chikritzhs, Stockwell, & Masters, 1997; Homel, Tomsen, & Thommeny, 1991; Stockwell, 1997). Police have a role in not only responding to the manifestation of harms, such as crime, injuries, assaults, domestic violence, stealing and sexual offences, but they also have a role in preventing problems, and thereby reducing alcohol and other drug-related harms (Doherty & Roche, 2003). Given the extent of alcohol consumption within licensed premises and the nature and extent of the harms, as well as the lack of opportunity to influence outcomes in other settings (e.g. the home), licensed premises offer police and other stakeholders a significant opportunity to influence positively the reduction of alcoholrelated harm. This research focuses specifically on the police role in policing licensed premises. Primarily, this research aims to investigate the factors which are relevant to why and how police officers respond to alcohol-related incidents inside and outside licensed premises. It examines the attitudes and beliefs of police and assesses their knowledge, capacity and ability to effectively police licensed premises. The research methodology uses three distinct surveys. Each contributes to understanding the motivations and practice of police officers in this important area of harm reduction. Study One involved a survey of police officers within a police district (Brisbane Central District) in Queensland, Australia and used a comprehensive questionnaire involving both quantitative and qualitative techniques. A key research outcome of Study One was the finding that officers had low levels of knowledge of the strategies that are effective in addressing alcohol-related harm both inside and outside licensed premises. Paradoxically, these officers also reported extensive recent experience in dealing with alcohol issues in these locations. In addition, these officers reported that alcohol was a significant contextual factor in the majority of matters to which they responded. Officers surveyed reported that alcohol increased the difficulty of responding to situations and that licensed premises (e.g. nightclubs, licensed clubs and hotels) were the most difficult contexts to police. Those surveyed were asked to self-assess their knowledge of the Liquor Act (Qld), which is the primary legislative authority in Queensland for regulating licensed premises. Surprisingly, well over half of the officers (65%) reported ‘no’ to ‘fair’ knowledge of the Act, despite officers believing that their skill level to police such premises was in the ‘good to very good range’. In an important finding, officers reported greater skill level to police outside licensed premises than inside such premises, indicating that officers felt less capable, from a skill perspective, to operate within the confines of a licensed premise than in the environment immediately outside such premises. Another key finding was that officers reported greater levels of training in responding to situations outside and around licensed premises than to situations inside licensed premises. Officers were also asked to identify the frequency with which they employed specified regulatory enforcement and community-based strategies. Irrespective of the type of response, ‘taking no action’ or passive policing interventions were not favoured by officers. The findings identified that officers favoured taking a range of strategies (sending home, releasing into the custody of friends, etc.) in preference to arrest. In another key finding, officers generally reported their support for operational stakeholder partnership approaches to policing licensed premises. This was evidenced by the high number of officers (over 90%) reporting that there should be shared responsibility for enforcing the provisions of the Liquor Act. Importantly, those surveyed also identified the factors which constrain or prevent them from policing licensed premises. Study Two involved interviewing a small but comprehensive group (n=11) of senior managers from within the Queensland Police Service (QPS) who have responsibility for setting operational and strategic policy. The aim of this study was to examine the attitudes, perceptions and influence that senior officers (at the strategy and policy-setting level) had on the officers at the operational level. This qualitative study was carried out using a purposive sampling (Denzin & Lincoln, 2005; Guba & Lincoln, 1989), focused interview and thematic analytic approach. The interview participants were drawn from three tiers of management at district, regional as well as the whole-of-organisational level. The first key theme emerging from the study related to role, in terms of both the QPS broader organisational role, and the individual officer role with respect to the policing of licensed premises. For the QPS organisational role, participants at all three strategic levels had a high degree of congruity as to the organisations service role; that is, to enhance public safety. With respect to participants’ beliefs as to whether police officers have knowledge and understanding of their individual roles concerning licensed premises (as opposed to the QPS role), participants reported most commonly that officers had a reasonable to clear understanding of their role. Participant comments also were supportive of the view that officers operating in the research area, Brisbane Central District (BCD), had a clearer understanding of their role than police operating in other locations. The second key theme to emerge identified a disparity between the knowledge and capability of specialist police, compared with general duties police, to police licensed premises. In fact, a number of the responses to a variety of questions differentiated specialist and general police in a range of domains. One such example related to the clarity of understanding of officer role. Participants agreed that specialist police (Liquor Enforcement & Proactive Strategies [LEAPS] officers) had more clarity of understanding in terms of their role than generalist police. Participants also were strongly of the opinion that specialist police had higher skill levels to deal with issues both inside and outside licensed premises. Some participants expressed the view that general duty police undertook purely response-related activities, or alternatively, dealt with lower order matters. Conversely, it was viewed that specialist police undertook more complex tasks because of their higher levels of knowledge and skill. The third key theme to emerge concerned the identification of barriers that serve to restrict or prevent police officers from policing licensed premises. Participant responses strongly indicated that there was a diversity of resourcing barriers that restrict police from undertaking their roles in licensed premises. Examples of such barriers were the lack of police and the low ratio of police to patrons, available officer time, and lack of organisational investment in skills and knowledge acquisition. However, some participants indicated that police resourcing in the BCD was appropriate and officers were equipped with sufficient powers (policy and legislation). Again, the issue of specialist police was raised by one participant who argued that increasing the numbers of specialist police would ameliorate the difficulties for police officers policing licensed premises. The fourth and last key theme to emerge from Study Two related to the perception of senior officers regarding the opportunity and capability of officers to leverage off external partnerships to reduce harms inside and outside licensed premises. Police working in partnership in BCD was seen as an effective harm reduction strategy and strongly supported by the participants. All participants demonstrated a high degree of knowledge as to who these partners were and could identify those government, non-government and community groups precisely. Furthermore, the majority of participants also held strong views that the partnerships were reasonably effective and worked to varying degrees depending on the nature of the partnership and issues such as resourcing. These senior officers identified better communication and coordination as factors that could potentially strengthen these partnerships. This research finding is particularly important for senior officers who have the capacity to shape the policy and strategic direction of the police service, not only in Queensland but throughout Australasia. Study Three examined the perceptions of those with links to the broader liquor industry (government, non-government and community but exclusive of police) concerning their understanding of the police role and the capacity of police to reduce alcohol-related harm inside and outside licensed premises, and their attitudes towards police. Participants (n=26) surveyed represented a range of areas including the liquor industry, business represenatives and government representatives from Queensland Fire and Rescue Service, Queensland Ambulance Service, Brisbane City Council and Queensland Health. The first key theme to emerge from Study Three related to participant understanding of the QPS organisational role, and importantly, individual officer role in policing licensed premises. In terms of participant understanding of the QPS role there was a clear understanding by the majority of participants that the police role was to act in ways consistent with the law and to otherwise engage in a range of enforcement-related activities. Participants saw such activities falling into two categories. The first category related to reactive policing, which included actions around responding to trouble in licensed premises, monitoring crowd controllers and removing trouble-makers. In the second category, proactive approaches, participants identified the following activities as consistent with that approach: early intervention with offenders, support of licensed premises operators and high visibility policing. When participants were asked about their understanding of individual officer roles in the policing of licensed premises, a range of responses were received but the consistent message that emerged was that there is a different role to be played by general duty (uniformed) police compared to specialist (LEAPS Unit) police, which reflects differences in knowledge, skill and capability. The second key theme that emerged from the data related to the external participants’ views of the knowledge and capability of specialist police, compared with general duty police, to police licensed premises. As noted in the first key theme, participants were universally of the view that the knowledge, skill and capability of police in specialist units (LEAPS Unit) was at a higher level than that of general duty police. Participants observed that these specialist officers were better trained than their colleagues in generalist areas and were therefore better able to intervene knowledgeably and authoritatively to deal with problems and issues as they emerged. Participants also reported that officers working within BCD generally had a positive attitude to their duties and had important local knowledge that they could use in the resolution of alcohol-related issues. Participants also commented on the importance of sound and effective QPS leadership, as well as the quality of the leadership in BCD. On both these measures, there was general consensus from participants, who reported positively on the importance and effectiveness of such leadership in BCD. The third key theme to emerge from Study Three concerned the identification of barriers that serve to restrict or prevent police officers from policing licensed premises. Overwhelmingly, external participants reported the lack of human resources (i.e. police officers) as the key barrier. Other resourcing limitations, such as available officer time, police computer systems, and the time taken to charge offenders, were identified as barriers. Some participants identified barriers in the liquor industry such as ‘dodgy operators’ and negative media attention as limitations. Other constraints to emerge related to government and policy barriers. These were reflected in comments about the collection by government of fees from licensees and better ‘powers’ for police to deal with offenders. The fourth and final key theme that emerged from Study Three related to the opportunities for and capability of police to leverage off external partnerships to reduce harms inside and outside licensed premises. Not surprisingly, participants had a comprehensive knowledge of a broad range of stakeholders, from a diversity of contexts, influential in addressing issues in licensed premises. Many participants reported their relationships with the police and other stakeholders as effective, productive and consistent with the objectives of partnering to reduce alcohol-related harm. On the other hand, there were those who were concerned with their relationship with other stakeholders, particularly those with a compliance function (e.g. Office of Liquor & Gaming Regulation [OLGR]). The resourcing limitations of partners and stakeholders were also raised as an important constraining factor in fulfilling the optimum relationship. Again, political issues were mentioned in terms of the impact on partnerships, with participants stating that there is at times political interference and that politicians complicate the relationships of stakeholders. There are some significant strengths with respect to the methodology of this research. The research is distinguished from previous work in that it examines these critical issues from three distinct perspectives (i.e. police officer, senior manager and external stakeholder). Other strengths relate to the strong theoretical framework that guides and informs the research. There are also some identified limitations, including the subjective nature of self-report data as well as the potential for bias by the author, which was controlled for using a range of initiatives. A further limitation concerns the potential for transferability and generalisability of the findings to other locations given the distinctive nature of the BCD. These limitations and issues of transferability are dealt with at length in the thesis. Despite a growing body of literature about contextual harms associated with alcohol, and specific research concerning police intervention in such contextual harms, there is still much to learn. While research on the subject of police engaging in alcohol-related incidents has focused on police behaviours and strategies in response to such issues, there is a paucity of research that focuses on the knowledge and understanding of officers engaged in such behaviours and practices. Given the scarcity of research dealing with the knowledge, skills and attitudes of police officers responding to harms inside and outside licensed premises, this research contributes significantly to what is a recent and growing body of research and literature in the field. The research makes a practical contribution to police agencies’ understanding of officer knowledge and police practice in ways that have the potential to shape education and training agendas, policy approaches around generalist versus specialist policing, strategic and operational strategy, as well as partnership engagements. The research also makes a theoretical contribution given that the research design is informed by the Three Circle
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Background: Side effects of the medications used for procedural sedation and analgesia in the cardiac catheterisation laboratory are known to cause impaired respiratory function. Impaired respiratory function poses considerable risk to patient safety as it can lead to inadequate oxygenation. Having knowledge about the conditions that predict impaired respiratory function prior to the procedure would enable nurses to identify at-risk patients and selectively implement intensive respiratory monitoring. This would reduce the possibility of inadequate oxygenation occurring. Aim: To identify pre-procedure risk factors for impaired respiratory function during nurse-administered procedural sedation and analgesia in the cardiac catheterisation laboratory. Design: Retrospective matched case–control. Methods: 21 cases of impaired respiratory function were identified and matched to 113 controls from a consecutive cohort of patients over 18 years of age. Conditional logistic regression was used to identify risk factors for impaired respiratory function. Results: With each additional indicator of acute illness, case patients were nearly two times more likely than their controls to experience impaired respiratory function (OR 1.78; 95% CI 1.19–2.67; p = 0.005). Indicators of acute illness included emergency admission, being transferred from a critical care unit for the procedure or requiring respiratory or haemodynamic support in the lead up to the procedure. Conclusion: Several factors that predict the likelihood of impaired respiratory function were identified. The results from this study could be used to inform prospective studies investigating the effectiveness of interventions for impaired respiratory function during nurse-administered procedural sedation and analgesia in the cardiac catheterisation laboratory.
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Impaired respiratory function (IRF) during procedural sedation and analgesia (PSA) poses considerable risk to patient safety as it can lead to inadequate oxygenation and ventilation. Risk factors that can be screened prior to the procedure have not been identified for the cardiac catheterization laboratory (CCL).
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Road safety barriers are used to redirect traffic at roadside work-zones. When filled with water, these barriers are able to withstand low to moderate impact speeds up to 50kmh-1. Despite this feature, there are challenges when using portable water-filled barriers (PWFBs) such as large lateral displacements as well as tearing and breakage during impact, especially at higher speeds. In this study, the authors explore the use of composite action to enhance the crashworthiness of PWFBs and enable their use at higher speeds. Initially, we investigated the energy absorption capability of water in PWFB. Then, we considered the composite action of a PWFB with the introduction of a steel frame to evaluate its impact on performance. Findings of the study show that the initial height of impact must be lower than the free surface level of water in a PWFB for the water to provide significant crash energy absorption. In general, impact of a road barrier that is 80% filled is a good estimation. Furthermore, the addition of a composite structure greatly reduces the probability of tearing by decreasing the strain and impact energy transferred to the shell container. This allows the water to remain longer in the barrier to absorb energy via inertial displacement and sloshing response. Information from this research will aid in the design of next generation roadside safety structures aimed to increase safety on modern roadways.
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Sequences with optimal correlation properties are much sought after for applications in communication systems. In 1980, Alltop (\emph{IEEE Trans. Inf. Theory} 26(3):350-354, 1980) described a set of sequences based on a cubic function and showed that these sequences were optimal with respect to the known bounds on auto and crosscorrelation. Subsequently these sequences were used to construct mutually unbiased bases (MUBs), a structure of importance in quantum information theory. The key feature of this cubic function is that its difference function is a planar function. Functions with planar difference functions have been called \emph{Alltop functions}. This paper provides a new family of Alltop functions and establishes the use of Alltop functions for construction of sequence sets and MUBs.
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This thesis provides an experimental and computational platform for investigating the performance and behaviour of water filled, plastic portable road safety barriers in an isolated impact scenario. A schedule of experimental impact tests were conducted assessing the impact response of an existing design of road safety barrier utilising a novel horizontal impact testing system. A coupled finite element and smooth particle hydrodynamic model of the barrier system was developed and validated against the results of the experimental tests. The validated model was subsequently used to assess the effect of certain composite materials on the impact performance of the water filled, portable road safety barrier system.
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A key derivation function is used to generate one or more cryptographic keys from a private (secret) input value. This paper proposes a new method for constructing a generic stream cipher based key derivation function. We show that our proposed key derivation function based on stream ciphers is secure if the underlying stream cipher is secure. We simulate instances of this stream cipher based key derivation function using three eStream finalist: Trivium, Sosemanuk and Rabbit. The simulation results show these stream cipher based key derivation functions offer efficiency advantages over the more commonly used key derivation functions based on block ciphers and hash functions.
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Background & aims: - Excess adiposity (overweight) is one of numerous risk factors for cardiometabolic disease. Most risk reduction strategies for overweight rely on weight loss through dietary energy restriction. However, since the evidence base for long-term successful weight loss interventions is scant, it is important to identify strategies for risk reduction independent of weight loss. The aim of this study was to compare the effects of isoenergetic substitution of dietary saturated fat (SFA) with monounsaturated fat (MUFA) via macadamia nuts on coronary risk compared to usual diet in overweight adults. Methods: - A randomised controlled trial design, maintaining usual energy intake, but manipulating dietary lipid profile in a group of 64 (54 female, 10 male) overweight (BMI > 25), otherwise healthy, subjects. For the intervention group, energy intakes of usual (baseline) diets were calculated from multiple 3 day diet diaries, and SFA was replaced with MUFA (target: 50%E from fat as MUFA) by altering dietary SFA sources and adding macadamia nuts to the diet. Both control and intervention groups received advice on national guidelines for physical activity and adhered to the same protocol for diet diary record keeping and trial consultations. Anthropometric and clinical measures were taken at baseline and at 10 weeks. Results: A significant increase in brachial artery flow-mediated dilation (p < 0.05) was seen in the monounsaturated diet group at week 10 compared to baseline. This corresponded to significant decreases in waist circumference, total cholesterol (p < 0.05), plasma leptin and ICAM-1 (p < 0.01). Conclusions: - In patient subgroups where adherence to dietary energy-reduction is poor, isoenergetic interventions may improve endothelial function and other coronary risk factors without changes in body weight. This trial was registered with the Australia New Zealand Clinical Trial Registry (ACTRN12607000106437).
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Objective To assess the effectiveness of an activity programme in improving function, quality of life, and falls in older people in residential care. Design Cluster randomised controlled trial with one year follow-up. Setting 41low level dependency residential carehomes in New Zealand. Participants 682 people aged 65 years or over. Interventions 330 residents were offered a goal setting and individualised activities of daily living activity programme by a gerontology nurse, reinforced by usual healthcare assistants; 352 residents received social visits. Main outcome measures Function (late life function and disability instruments, elderly mobility scale, FICSIT-4
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The growth of graphene on SiC/Si substrates is an appealing alternative to the growth on bulk SiC for cost reduction and to better integrate the material with Si based electronic devices. In this paper, we present a complete in-situ study of the growth of epitaxial graphene on 3C SiC (111)/Si (111) substrates via high temperature annealing (ranging from 1125˚C to 1375˚C) in ultra high vacuum (UHV). The quality and number of graphene layers have been thoroughly investigated by using x-ray photoelectron spectroscopy (XPS), while the surface characterization have been studied by scanning tunnelling microscopy (STM). Ex-situ Raman spectroscopy measurements confirm our findings, which demonstrate the exponential dependence of the number of graphene layer from the annealing temperature.
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In this study, we have demonstrated that the preproghrelin derived hormones, ghrelin and obestatin, may play a role in ovarian cancer. Ghrelin and obestatin stimulated an increase in cell migration in ovarian cancer cell lines and may play a role in cancer progression. Ovarian cancer is the leading cause of death among gynaecological cancers and is the sixth most common cause of cancer-related deaths in women in developed countries. As ovarian cancer is difficult to diagnose at a low tumour grade, two thirds of ovarian cancers are not diagnosed until the late stages of cancer development resulting in a poor prognosis for the patient. As a result, current treatment methods are limited and not ideal. There is an urgent need for improved diagnostic markers, as well better therapeutic approaches and adjunctive therapies for this disease. Ghrelin has a number of important physiological effects, including roles in appetite regulation and the stimulation of growth hormone release. It is also involved in regulating the immune, cardiovascular and reproductive systems and regulates sleep, memory and anxiety, and energy metabolism. Over the last decade, the ghrelin axis, (which includes the hormones ghrelin and obestatin and their receptors), has been implicated in the pathogenesis of many human diseases and it may t may also play an important role in the development of cancer. Ghrelin is a 28 amino acid peptide hormone that exists in two forms. Acyl ghrelin (usually referred to as ghrelin), has a unique n-octanoic acid post-translational modification (which is catalysed by ghrelin O-acyltransferase, GOAT), and desacyl ghrelin, which is a non-octanoylated form. Octanoylated ghrelin acts through the growth hormone secretagogue receptor type 1a (GHSR1a). GHSR1b, an alternatively spliced isoform of GHSR, is C-terminally truncated and does not bind ghrelin. Ghrelin has been implicated in the pathophysiology of a number of diseases Obestatin is a 23 amino acid, C-terminally amidated peptide which is derived from preproghrelin. Although GPR39 was originally thought to be the obestatin receptor this has been disproven, and its receptor remains unknown. Obestatin may have as diverse range of roles as ghrelin. Obestatin improves memory, inhibits thirst and anxiety, increases pancreatic juice secretion and has cardioprotective effects. Obestatin also has been shown to regulate cell proliferation, differentiation and apoptosis in some cell types. Prior to this study, little was known regarding the functions and mechanisms of action ghrelin and obestatin in ovarian cancer. In this study it was demonstrated that the full length ghrelin, GHSR1b and GOAT mRNA transcripts were expressed in all of the ovarian-derived cell lines examined (SKOV3, OV-MZ-6 and hOSE 17.1), however, these cell lines did not express GHSR1a. Ovarian cancer tissue of varying stages and normal ovarian tissue expressed the coding region for ghrelin, obestatin, and GOAT, but not GHSR1a, or GHSR1b. No correlations between cancer grade and the level of expression of these transcripts were observed. This study demonstrated for the first time that both ghrelin and obestatin increase cell migration in ovarian cancer cell lines. Treatment with ghrelin (for 72 hours) significantly increased cell migration in the SKOV3 and OV-MZ-6 ovarian cancer cell lines. Ghrelin (100 nM) stimulated cell migration in the SKOV3 (2.64 +/- 1.08 fold, p <0.05) and OV-MZ-6 (1.65 +/- 0.31 fold, p <0.05) ovarian cancer cell lines, but not in the representative normal cell line hOSE 17.1. This increase in migration was not accompanied by an increase in cell invasion through Matrigel. In contrast to other cancer types, ghrelin had no effect on proliferation. Ghrelin treatment (10nM) significantly decreased attachment of the SKOV3 ovarian cancer cell line to collagen IV (24.7 +/- 10.0 %, p <0.05), however, there were no changes in attachment to the other extracellular matrix molecules (ECM) tested (fibronectin, vitronectin and collagen I), and there were no changes in attachment to any of the ECM molecules in the OV-MZ-6 or hOSE 17.1 cell lines. It is, therefore, unclear if ghrelin plays a role in cell attachment in ovarian cancer. As ghrelin has previously been demonstrated to signal through the ERK1/2 pathway in cancer, we investigated ERK1/2 signalling in ovarian cancer cell lines. In the SKOV3 ovarian cancer cell line, a reduction in ERK1/2 phosphorylation (0.58 fold +/- 0.23, p <0.05) in response to 100 nM ghrelin treatment was observed, while no significant change in ERK1/2 signalling was seen in the OV-MZ-6 cell line with treatment. This suggests that this pathway is unlikely to be involved in mediating the increased migration seen in the ovarian cancer cell lines with ghrelin treatment. In this study ovarian cancer tissue of varying stages and normal ovarian tissue expressed the coding region for obestatin, however, no correlation between cancer grade and level of obestatin transcript expression was observed. In the ovarian-derived cell lines studied (SKOV3, OV-MZ-6 and hOSE 17.1) it was demonstrated that the full length preproghrelin mRNA transcripts were expressed in all cell lines, suggesting they have the ability to produce mature obestatin. This is the first study to demonstrate that obestatin stimulates cell migration and cell invasion. Obestatin induced a significant increase in migration in the SKOV3 ovarian cancer cell line with 10 nM (2.80 +/- 0.52 fold, p <0.05) and 100 nM treatments (3.12 +/- 0.68 fold, p <0.05) and in the OV-MZ-6 cancer cell line with 10 nM (2.04 +/- 0.10 fold, p <0.01) and 100 nM treatments (2.00 +/- 0.37 fold, p <0.05). Obestatin treatment did no affect cell migration in the hOSE 17.1normal ovarian epithelial cell line. Obestatin treatment (100 nM) also stimulated a significant increase in cell invasion in the OV-MZ-6 ovarian cancer cell line (1.45 fold +/- 0.13, p <0.05) and in the hOSE17.1 normal ovarian cell line cells (1.40 fold +/- 0.04 and 1.55 fold +/- 0.05 respectively, p <0.01) with 10 nM and 100 nM treatments. Obestatin treatment did not stimulate cell invasion in the SKOV3 ovarian cancer cell line. This lack of obestatin-stimulated invasion in the SKOV3 cell line may be a cell line specific result. In this study, obestatin did not stimulate cell proliferation in the ovarian cell lines and it has previously been shown to have no effect on cell proliferation in the BON-1 pancreatic neuroendocrine and GC rat somatotroph tumour cell lines. In contrast, obestatin has been shown to affect cell proliferation in gastric and thyroid cancer cell lines, and in some normal cell lines. Obestatin also had no effect on attachment of any of the cell lines to any of the ECM components tested (fibronectin, vitronectin, collagen I and collagen IV). The mechanism of action of obestatin was investigated further using a two dimensional-difference in gel electrophoresis (2D-DIGE) proteomic approach. After treatment with obestating (0, 10 and 100 nM), SKOV3 ovarian cancer and hOSE 17.1 normal ovarian cell lines were collected and 2D-DIGE analysis and mass spectrometry were performed to identify proteins that were differentially expressed in response to treatment. Twenty-six differentially expressed proteins were identified and analysed using Ingenuity Pathway Analysis (IPA). This linked 16 of these proteins in a network. The analysis suggested that the ERK1/2 MAPK pathway was a major mediator of obestatin action. ERK1/2 has previously been shown to be associated with obestatin-stimulated cell proliferation and with the anti-apoptotic effects of obestatin. Activation of the ERK1/2 signalling pathway by obestatin was, therefore, investigated in the SKOV3 and OV-MZ-6 ovarian cancer cell lines using anti-active antibodies and Western immunoblots. Obestatin treatment significantly decreased ERK1/2 phosphorylation at higher obestatin concentrations in both the SKOV3 (100 nM and 1000 nM) and OV-MZ-6 (1000 nM) cell lines compared to the untreated controls. Currently, very little is known about obestatin signalling in cancer. This thesis has demonstrated for the first time that the ghrelin axis may play a role in ovarian cancer migration. Ghrelin and obestatin increased cell migration in ovarian cancer cell lines, indicating that they may be a useful target for therapies that reduce ovarian cancer progression. Further studies investigating the role of the ghrelin axis using in vivo ovarian cancer metastasis models are warranted.
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Background Epidemiological studies have shown a reduced incidence of cardiovascular disease in the Mediterranean population attributed to the consumption of dietary olive oil rich in antioxidants. This has lead to increased interest in the antioxidant properties of other phenolic compounds of olive tree products. It has been suggested that olive leaf extract may also have health benefits due to its antioxidant and anti-inflammatory activities. Antioxidants can prevent the effects of oxidative metabolism by scavenging free radicals and decreasing the hyperactivity of platelets associated with the development of occlusive thrombosis. No studies to date have investigated the effects of olive leaf extract on platelet function to our knowledge. Improved understanding of the antioxidant properties of olive leaf extract and its effect on platelet function could lead to improved cardiovascular health. Objective The current study used an olive leaf extract prepared from the Olea europaea L. tree. The aim was to determine if polyphenols in olive leaf extract would reduce platelet activity and, to establish an optimal dose in vitro that would reduce platelet aggregation and ATP release. Design Eleven subjects with normal platelet counts (150–400 x 109/L) were recruited for the current in vitro study. Olive leaf extract was added to citrated whole blood to obtain five concentrations ranging from 5.4 ug/mL to 54.0 ug/mL for a dose response curve. Baseline samples, without olive leaf extract were used as a negative control for each subject. After 2 hours incubation with olive leaf extract samples were analyzed for platelet aggregation and ATP release from platelets stimulated by the addition of collagen. Results Whole blood analysis (n=11) showed a clear dose-dependant reduction in platelet aggregation with the increasing olive leaf extract concentrations (p<0.0001). There was also a similar decrease in ATP release from collagen stimulated platelets (p=0.02). Conclusion In the current study the olive leaf extract obtained from Olea europaea L. inhibited platelet aggregation and ATP release from collagen stimulated platelets in vitro. This study suggests olive leaf extract may prevent occlusive thrombosis by reducing platelet hyperactivity.
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This study investigated how and to what degree “hybrid photography”—the simultaneous use of indexical and fictional properties and strategies— innovates the representation of animals within animalcentric, ecocentric frameworks. Design theory structured this project’s Practice-led, Visual research methodology framework. Grounded theory processes articulated emerging categories of hybrid photography through systematically and comparatively treating animal photography works for reflexive analysis. Design theory then applied and clarified categories, developing practice that re-visualised shark perspectives as new ecological discourse. Shadows, a creative practice installation, realised a full-scale photographic investigation into shark and marine animal realities of a specific environment—Heron Island and Gladstone, Great Barrier Reef—facing ecological crisis from dredging and development at Gladstone Harbour. Works rendered and explored hybrid photography’s capacity for illuminating nonhuman animals, in particular, sharks, and comprise 65% of this project’s weighting. This exegetical paper offers a definition, strategies and evaluation of hybrid photography in unsettling animal perspectives as effective ecological discourse, and comprises 35%.