608 research outputs found

    The experience of vasa praevia for Australian midwives: A qualitative study

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    © 2018 Australian College of Midwives Background: Vasa praevia can cause stillbirth or early neonatal death if it is not diagnosed antenatally and managed appropriately. Experiencing undiagnosed vasa praevia during labour is challenging and traumatic for women and their care providers. Little is known about the experiences of midwives who care for these women. Aim: To investigate the experience of Australian midwives caring for women with undiagnosed vasa praevia during labour and birth. Methods: A qualitative descriptive study was conducted with midwives in Australia who had cared for at least one woman with vasa praevia during 2010–2016. Semi-structured in-depth telephone interviews were conducted and analysed using thematic analysis. Findings: Twelve of the 20 midwives interviewed were involved in a neonatal death and/or near-miss due to vasa praevia. There was one over-arching theme, which described the ‘devastating and dreadful experience’ for the midwives. This had two inter-related categories of feeling the personal impacts and addressing the professional processes. Feeling scared, shocked, and guilty described how the experience took its toll on the midwives personally. The professional processes included working in organised chaos; feeling for the parents; finding communication to be hard; and, doing their best to save the baby. Discussion: Caring for women who experienced ruptured vasa praevia had a profound impact on the emotional and professional well-being of midwives even when the baby survived. Conclusion: Ruptured vasa praevia was recognised as a traumatic experience that warrants serious considerations from maternity care providers, managers and policy makers. Midwives should be supported and adequately prepared to cope with traumatic events

    A combined numerical and experimental investigation of disengaged wet clutch system power loss

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    A combined numerical and experimental investigation of disengaged wet clutch system power los

    Effect of Mesh Phasing on the Transmission Efficiency and Dynamic Performance of Wheel Hub Planetary Gear Sets

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    Transmission efficiency and refinement of planetary wheel hub gearing system are key design attributes for heavy and off-highway vehicles. Reduction of power loss, directly leading to the development of new generation ECO-axles requires analysis of gear contacting conditions for lubricated conjunctions to determine frictional performance. This is also affected by gear dynamics, which is a prerequisite for assessment of noise, vibration and harshness performance. Therefore, a combined tribo-dynamic analysis is essential. There is a dearth of such holistic analysis, particularly for the case of wheel hub planetary systems. The paper presents such an analysis, which has not hitherto been reported in literature. The inexorable interplay of transmission efficiency and noise, vibration and harshness refinement is demonstrated. The key attributes of noise, vibration and harshness refinement and transmission efficiency can pose contrary requirements and near-optimal conditions can be highlighted by mesh phasing of gearing contacts, thus alleviating the need for more complex gear teeth modifications entailing prohibitive manufacturing costs

    Transient Thermal Analysis of Mixed-elastohydrodynamic Contact of High Performance Transmission in a Dry Sump Environment

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    Fuel efficiency is one of the main concerns in the optimisation of modern racing transmissions. The dry sump transmissions are the preferred choice for high performance racing applications. While it provides adequate lubricant for gear contacts, it minimises the system churning losses, and therefore enhances the system efficiency. An important aspect is assessing its thermal performance in removing the generated frictional heat. The generated heat in the highly loaded high shear contacts of racing transmissions should be dissipated through use of directed impinging oil jets and in an air–oil mist environment. The paper presents an integrated tribological and three-dimensional computational fluid dynamics analysis for a spur gear pair, incorporated into an overall finite element model to evaluate the quantity of generated heat and its removal rate from the rotating gear surfaces. Furthermore, the temperature distribution in the circumferential direction is predicted and used to evaluate transient temperature distribution over representative race laps. Such an approach has not hitherto been reported in literature

    New Insights into the Genetic Regulation of Homologue Disjunction in Mammalian Oocytes

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    Mammalian oocytes execute a unique meiotic programme involving 2 arrest stages and an unusually protracted preamble to chromosome segregation during the first meiotic division (meiosis I). How mammalian oocytes successfully navigate their exceptional meiotic journey has long been a question of immense interest. Understanding the minutiae of female mammalian meiosis I is not merely of academic interest as 80–90% of human aneuploidy is the consequence of errors arising at this particular stage of oocyte maturation, a stage with a peculiar vulnerability to aging. Recent evidence indicates that oocytes employ many of the same cast of proteins during meiosis I as somatic cells do during mitosis, often to execute similar tasks, but intriguingly, occasionally delegate them to unexpected and unprecedented roles. This is epitomised by the master cell-cycle regulon, the anaphase-promoting complex or cyclosome (APC/C), acting in concert with a critical APC/C-targeted surveillance mechanism, the spindle assembly checkpoint (SAC). Together, the APC/C and the SAC are among the most influential entities overseeing the fidelity of cell-cycle progression and the precision of chromosome segregation. Here I review the current status of pivotal elements underpinning homologue disjunction in mammalian oocytes including spindle assembly, critical biochemical anaphase-initiating events, APC/C activity and SAC signalling along with contemporary findings relevant to progressive oocyte SAC dysfunction as a model for age-related human aneuploidy

    Effect of teeth micro-geometrical form modification on contact kinematics and efficiency of high performance transmissions

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    Light weight, compactness and efficiency are key objectives in high performance vehicular transmission systems, which are subject to large variations in torque and power. Pitch line velocities of up to 52 m/s and teeth pair contact pressures of up to 3 GPa are routinely encountered under race conditions. Contact patch asymmetry due to angular misalignments between input and output shafts leads to the generation of high edge stress discontinuities on gear flanks, inducing fatigue spalling which affects system durability. Crowning is widely used as a palliative measure to mitigate these undesired effects. These problems can be further exacerbated by contact footprint truncation. The paper presents a new approach to modelling the kinematics and contact micro-geometry of meshing conjunctions of involute spur gears with profile and lead modifications. A time-efficient analytical method is presented to accurately determine the contact footprint and kinematics, leading to the solution of highly loaded non-Newtonian mixed thermo-elastohydrodynamic contact under the extreme prevalent conditions of high performance vehicular transmissions. The effect of tooth form modification on contact footprint truncation, contact kinematics and generated frictional power loss is investigated. This approach has not hitherto been reported in literature

    An intervention to improve outcomes of falls in dementia: the DIFRID mixed-methods feasibility study:A mixed methods study to develop and assess the feasibility of the DIFRID intervention

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    Background : Fall-related injuries are a significant cause of morbidity and mortality in people with dementia (PWD). There is presently little evidence to guide the management of such injuries, and yet there are potentially substantial benefits to be gained if the outcome of these injuries could be improved. This study aimed to design an appropriate new healthcare intervention for PWD following a fall and to assess the feasibility of its delivery in the UK National Health Service. Objective (s): To determine whether it is possible to design an intervention to improve outcomes of falls in dementia; to investigate the feasibility and acceptability of the DIFRID intervention; to investigate the feasibility of a future randomised controlled trial (RCT) and data collection tools needed to evaluate the effectiveness and efficiency of the DIFRID intervention. Design : Mixed-methods feasibility study. Methods : A systematic review (using Cochrane methodology) and realist review (using RAMESES methodology) explored the existing evidence base and developed programme theories. Searches were carried out in Nov 2015 (updated Jan 2018) for effectiveness studies and August 2016 for economic studies. A prospective observational study identified service use via participant diary completion. Qualitative methods (semi-structured interviews, focus groups, and observation) were used to explore: current practice; stakeholder perspectives of the health and social care needs of PWD following a fall; ideas for intervention; and barriers and facilitators to change. Each of these datasets informed intervention development, via Delphi consensus methods. Finally, a single-arm feasibility study with embedded process evaluation was conducted. Setting : Community. Participants : PWD presenting with falls needing healthcare attention in each setting at 3 sites and their carers. Professionals delivering the intervention, responsible for training and supervision and members of the intervention team. Professionals responsible for approaching and recruiting participants. Interventions: A complex multidisciplinary therapy intervention. Physiotherapists, occupational therapists, and support workers delivered up to 22 sessions of tailored activities in the PWD’s home or local area over a period of 12 weeks. Main outcome measures: Assessment of feasibility of study procedures; assessment of the acceptability, feasibility and fidelity of intervention components; assessment of suitability and acceptability of outcome measures for PWD and carers (number of falls; quality of life; fear of falling; activities of daily living; goal setting; health utilisation; carer burden). Results : A multidisciplinary intervention delivered in PWDs’ own homes was designed based on qualitative work, realist review and recommendations of the consensus panel. The intervention was delivered to 11 PWD. The study suggested that the intervention is both feasible and acceptable to stakeholders. A number of modifications was recommended to address some of the issues arising during feasibility testing. Measurement of outcome measures was successful. Limitations : Recruitment to the feasibility study was lower than expected and therefore the intervention needs to be tested with a larger number of PWD. Conclusions : The study has highlighted the feasibility of delivering a creative, tailored, individual approach to intervention for PWD following a fall. Although the intervention required greater investment of time than usual practice, many staff valued the opportunity to work more closely with PWD and carers. Future work : We conclude that further research is now needed to refine this intervention in the context of a pilot randomised controlled trial

    Incidental diagnosis of diseases on un-enhanced helical computed tomography performed for ureteric colic

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    BACKGROUND: Patients presenting in the emergency room with flank pain suggestive of acute ureteric colic may have alternative underlying conditions mimicking ureteric stones. An early diagnosis and appropriate treatment for other causes of flank pain is important. The majority of centers around the world are increasingly using un-enhanced helical CT (UHCT) for evaluation of ureteric colic. This study was conducted to determine the incidence and spectrum of significant incidental diagnoses established or suggested on UHCT performed for suspected renal/ureteric colic. METHODS: Urologist and radiologist reviewed 233 consecutive UHCT, performed for suspected renal/ureteral colic along with assessment of the medical records. Radiological diagnoses of clinical entities not suspected otherwise were analyzed. All other relevant radiological, biochemical and serological investigations and per-operative findings were also noted. RESULTS: Ureteral calculi were identified in 148 examinations (64%), findings of recent passage of calculi in 10 (4%) and no calculus in 75 examinations (32%). Overall the incidental findings (additional or alternative diagnosis) were found in 28 (12%) CT scans. Twenty (71%) of these diagnoses were confirmed by per-operative findings, biopsy, and other radiological and biochemical investigations or on clinical follow up. CONCLUSION: A wide spectrum of significant incidental diagnoses can be identified on UHCT performed for suspected renal/ureteral colic. In the present series of 233 consecutive CT examinations, the incidence of incidental diagnosis was 12%

    A System Dynamics Approach for Modeling Return on Quality for ECS Industry

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    The Electronic Components and Systems industry (ECS) is characterized by long lead times and high market volatility. Besides fast technological development within this industry, cyclic market up- and downturns are influencing the semiconductor market. Therefore, adequate capacity and inventory management as well as continuous process improvements are important success factors for semiconductor companies to be competitive. In this study, the authors focus on a manufacturing excellence approach to increase front-end supply reliability and the availability of inventory within the customer order decoupling point. Here, development and manufacturing processes must be designed in a way that highest levels of product quality, flexibility, time and costs are reached. The purpose of this study is to explore the impact of return on quality in manufacturing systems. Therefore, multimethod simulation modelling including discrete-event and system dynamics simulation is applied

    CT scanning for diagnosing blunt ureteral and ureteropelvic junction injuries

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    <p>Abstract</p> <p>Background</p> <p>Blunt ureteral and ureteropelvic (UPJ) injuries are extremely rare and very difficult to diagnose. Many of these injuries are missed by the initial trauma evaluation.</p> <p>Methods</p> <p>Trauma registry data was used to identify all blunt trauma patients with ureteral or UPJ injuries, from 1 April 2001 to 30 November 2006. Demographics, injury information and outcomes were determined. Chart review was then performed to record initial clinical and all CT findings.</p> <p>Results</p> <p>Eight patients had ureteral or UPJ injuries. Subtle findings such as perinephric stranding and hematomas, and low density retroperitoneal fluid were evident on all initial scans, and prompted delayed excretory scans in 7/8 cases. As a result, ureteral and UPJ injuries were diagnosed immediately for these seven patients. These findings were initially missed in the eighth patient because significant associated visceral findings mandated emergency laparotomy. All ureteral and UPJ injuries have completely healed except for the case with the delay in diagnosis.</p> <p>Conclusion</p> <p>Most blunt ureteral and UPJ injuries can be identified if delayed excretory CT scans are performed based on initial CT findings of perinephric stranding and hematomas, or the finding of low density retroperitoneal fluid.</p
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