681 research outputs found

    The accuracy of visualized treatment objectives in bimaxillary protrusion patients

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    Magister Scientiae Dentium - MSc(Dent)The aim of this research project was to assess the accuracy of four different types of VTO [Steyn (1979), Jacobson and Sadowsky (1980), Ricketts (1982) and Holdaway (1984)], in predicting the final result of the incisor and soft tissue response to orthodontic treatment in bimaxillary protrusive patients.South Afric

    Drag force as a function of cross section and angle of attack. A hydraulic laboratory dataset for numerical validation

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    This data relates to a set of hydraulic laboratory experiments in which the flow around four cross-sections was investigated. Each cross section was examined at four angles of attack (0, 5, 10, 90°), seven velocities (0–0.7 m/s in 0.1 m/s steps) and two flow directions. The data is primarily from an array of load cell which monitored the loading on the cross-sections during testing in six degrees of freedom during testing. Video and photographs are also included

    Chasing electrons : exploring the redox balance of platelet functions

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    The platelet redox environment consists of the blood plasma and within it the lowmolecular weight thiols glutathione and cysteine. Both glutathione and cysteine exist as independent redox couples comprising carefully controlled ratios of the reduced (GSH, Cys) and oxidised (GSSG, CySS) form of each thiol. These ratios yield a GSH/GSSG redox potential and a Cys/CySS redox potential in the plasma. Changes in the redox status of the plasma are manifested by alterations in either the glutathione or cysteine redox potential and are associated with the progression of a large number of disease states including cancer, atherosclerosis and schizophrenia. In addition, oxidative changes in either of the plasma redox potentials have been directly linked with risk factors for cardiovascular disease. The post-translational modification of critical cysteine thiol groups on proteins is linked to such alterations in both the GSH/GSSG and Cys/CySS redox potentials and occurs extracellularly and intracellularly. Platelet integrins in particular are prime targets for redox modification due to their high cysteine content. Although the role of thiol/ disulphide bond exchange in platelet activation is established the effects of a changing redox environment on platelet reactivity are unclear. The aims of this thesis therefore, are to explore the impact and consequences of such changes on platelet function. Platelet activation was significantly diminished in the presence of either reducing GSH/GSSG or Cys/CySS redox potentials. Moreover, this response was most notable when platelets were activated with collagen only. The redox modulated effects were shown to be specific to the integrin ɑ2β1, through a mechanism involving disulphide bond reduction. An analysis of the platelet integrin β subunits revealed the presence of the greatest number of potentially reactive cysteine residues within the Pi subunit when compared to the other platelet integrin beta subunit β3. Furthermore, platelet proteins were S-glutathionylated in a reducing extracellular redox environment. The findings of this thesis reveal for the first time how exquisitely sensitive collagen-induced platelet activation is to alterations in the external redox environment. This, in fact, is potentially a novel demonstration of reductive stress regulating platelet reactivity and provides a novel avenue for therapeutic intervention using physiological redox reagents or their precursors

    The microbiome and the pathophysiology of asthma

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    Asthma is a chronic respiratory disease whose prevalence is increasing in the western world. Recently research has begun to focus on the role the microbiome plays in asthma pathogenesis in the hope of further understanding this respiratory disorder. Considered sterile until recently, the lungs have revealed themselves to contain a unique microbiota. A shift towards molecular methods for the quantification and sequencing of microbial DNA has revealed that the airways harbour a unique microbiota with apparent, reproducible differences present between healthy and diseased lungs. There is a hope that in classifying the microbial load of the asthmatic airway an insight may be afforded as to the possible role pulmonary microbes may have in propagating an asthmatic airway response. This could potentially pave the way for new therapeutic strategies for the treatment of chronic lung conditions such as asthma

    Description of an 8 MW reference wind turbine

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    An 8 MW wind turbine is described in terms of mass distribution, dimensions, power curve, thrust curve, maximum design load and tower configuration. This turbine has been described as part of the EU FP7 project LEANWIND in order to facilitate research into logistics and naval architecture efficiencies for future offshore wind installations. The design of this 8 MW reference wind turbine has been checked and validated by the design consultancy DNV-GL. This turbine description is intended to bridge the gap between the NREL 5 MW and DTU 10 MW reference turbines and thus contribute to the standardisation of research and development activities in the offshore wind energy industry

    Growing Up in Ireland: Growing up and developing as an adult: A review of the literature on selected topics pertaining to cohort ’98 at age 20 years. ESRI Report December 2020.

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    The goal of this report is to provide research information on selected potential research questions using data collected in interviews with 20-year-olds and their parents. At the time of writing, fieldwork was under way, so the topics of the survey were known but not the outcome of the interviews. The research questions address the central outcomes of the Growing Up in Ireland study that contribute to building developmental trajectories from childhood to adulthood: socio-emotional well-being; educational and cognitive development; physical health and growth. Three potential research questions are outlined under each outcome and provide a short supporting review of the national and international literature, followed by a description of the measures in Growing Up in Ireland useful in exploring the topic. While there is a wide array of possible research questions with a dataset such as this, the selected topics are those that offer new potential given the measures at this particular wave and/or are particularly salient to this phase of the life-course

    Gastric aspiration and its role in airway inflammation

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    Gastro-Oesophageal Reflux (GOR) has been associated with chronic airway diseases while the passage of foreign matter into airways and lungs through aspiration has the potential to initiate a wide spectrum of pulmonary disorders. The clinical syndrome resulting from such aspiration will depend both on the quantity and nature of the aspirate as well as the individual host response. Aspiration of gastric fluids may cause damage to airway epithelium, not only because acidity is toxic to bronchial epithelial cells but also due to the effect of digestive enzymes such as pepsin and bile salts. Experimental models have shown that direct instillation of these factors to airways epithelia cause damage with a consequential inflammatory response. The pathophysiology of these responses is gradually being dissected, with better understanding of acute gastric aspiration injury, a major cause of acute lung injury, providing opportunities for therapeutic intervention and potentially, ultimately, improved understanding of the chronic airway response to aspiration. Ultimately, clarification of the inflammatory pathways which are related to micro-aspiration via pepsin and bile acid salts may eventually progress to pharmacological intervention and surgical studies to assess the clinical benefits of such therapies in driving symptom improvement or reducing disease progression

    Growing Up in Ireland. National Longitudinal Study of Children. Report 6 2018

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    This report provides a descriptive analysis of the findings from detailed interviews with 13-year-olds and their parents in the Growing Up in Ireland study. The purpose of the report is to present a broad, comprehensive overview of the lives of the Child Cohort at age 13 and to describe how they are faring in important areas of their lives. Preliminary key findings from data collected at age 13 were published in November 2012. This report explores data from this wave of data collection in more detail and expands on the issues covered in those key findings. In the current report, findings are explored on a longitudinal basis, allowing insights into developmental trajectories for the cohort since the age of nine years. Exploration into interactions between multiple factors on the lives of young people are also presented, a type of analysis that was not possible in previous cross-sectional reports

    The Emergence of Spanking Among a Representative Sample of Children Under 2 Years of Age in North Carolina

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    Spanking is common in the United States but less common in many European countries in which it has been outlawed. Being spanked has been associated with child abuse victimization, poor self-esteem, impaired parent–child relationships, and child and adult mental health, substance abuse, and behavioral consequences. Being spanked as a child has also been shown to increase the likelihood of abusing one's own children or spouse as an adult. Spanking of very young children less than two is almost never recommended even among experts that consider spanking as reasonable in some circumstances. Using a cross-sectional anonymous telephone survey, we describe spanking rates among a representative sample of North Carolina mothers of children less than 2 years old and the association of spanking with demographic characteristics. A substantial proportion of mothers admit to spanking their very young children. The rate of spanking in the last year among all maternal respondents was 30%. Over 5% of the mothers of 3-month olds reported spanking. Over 70% of the mothers of 23-month olds reported spanking. Increased spanking was associated with higher age of the child and lower maternal age. With every month of age, a child had 27% increased odds of being spanked. Early spanking has been shown to be associated with poor cognitive development in early childhood. Further, early trauma has been shown to have significant effects on the early developing brain. It is therefore critical that health and human services professionals address the risk of corporal punishment as a method of discipline early in the life of the child. The spanking of very young children may be an appropriate locus for policy and legislative debates regarding corporal punishment

    Effects of age-associated regional changes in aortic stiffness on human hemodynamics revealed by computational modeling

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    Although considered by many as the gold standard clinical measure of arterial stiffness, carotid-to-femoral pulse wave velocity (cf-PWV) averages material and geometric properties over a large portion of the central arterial tree. Given that such properties may evolve differentially as a function of region in cases of hypertension and aging, among other conditions, there is a need to evaluate the potential utility of cf-PWV as an early diagnostic of progressive vascular stiffening. In this paper, we introduce a data-driven fluid-solid-interaction computational model of the human aorta to simulate effects of aging-related changes in regional wall properties (e.g., biaxial material stiffness and wall thickness) and conduit geometry (e.g., vessel caliber, length, and tortuosity) on several metrics of arterial stiffness, including distensibility, augmented pulse pressure, and cyclic changes in stored elastic energy. Using the best available biomechanical data, our results for PWV compare well to findings reported for large population studies while rendering a higher resolution description of evolving local and global metrics of aortic stiffening. Our results reveal similar spatio-temporal trends between stiffness and its surrogate metrics, except PWV, thus indicating a complex dependency of the latter on geometry. Lastly, our analysis highlights the importance of the tethering exerted by external tissues, which was iteratively estimated until hemodynamic simulations recovered typical values of tissue properties, pulse pressure, and PWV for each age group.</p
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