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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Exploring the utility of 3D-skin models to evaluate trans-dermal uptake of flame retardants from indoor dust and consumer products

Pawar, Gopal January 2017 (has links)
The aim of this research was to evaluate the utility of innovative in vitro techniques as an alternatives for human/animal tissues to study the transdermal uptake of organic flame retardants from indoor dust and consumer products. Firstly, we successfully designed and applied an in vitro physiologically based extraction test to provide new insights into the dermal bioaccessibility of various FRs from indoor dust. These investigations revealed the bioaccessible fraction for the brominated flame retardants (BFRs) α-, β-and γ- HBCD and TBBPA to 1:1 (sweat/sebum) mixture to be 41%, 47%, 50% and 40%, respectively, while for the phosphate flame retardants (PFRs) TCEP, TCIPP and TDCIPP, the values were 10%, 17% and 19%. With the exception of TBBP A, the presence of cosmetics had a significant effect (p < 0.05) on the bioaccessibility of our target FRs from indoor dust. The presence of cosmetics decreased the bioaccessibility of HBCDs from indoor dust, whereas shower gel and sunscreen lotion enhanced the bioaccessibility of target PFRs. Secondly, we developed a protocol for studying dennal uptake of legacy and novel brominated flame retardants using two 3D-HSE (three dimensional human skin equivalent tissue) models, EpiDerm™ and EPISKIN™ in compliance with the OECD guidelines 428. Overall, results showed a significant negative correlation between the permeability constant of FRs and their Log K_ow values. We also mimicked real life exposure scenarios by exposing the skin surface in turn to FR-containing dust, reference material plastics and upholstered fabrics. Our findings showed that under such scenarios dermal exposure to FRs was appreciable for UK adults and toddlers. For example, for dust exposure, our estimates of daily intake indicated toddlers to be 10 times more highly exposed than adults in the presence of sweat and sebum. This differential exposure is likely attributable to more dust adhering to toddler's skin and their higher exposed skin surface area to body weight ratio compared to adults.
142

Behavioural adjuvants to vaccination

Campbell, John P. January 2010 (has links)
This thesis investigated the effects of acute eccentric exercise on the immune response to vaccination in young humans. Study one investigated whether the efficacy of the eccentric exercise intervention was affected by manipulating the timings of exercise prior to influenza vaccination. Three exercise groups were vaccinated immediately, 6 hr or 48 hr after exercise and antibody responses at 28 days post-vaccination were compared to those from a resting control group. All participants exhibited robust antibody responses to the vaccine and no effect of exercise was observed; therefore, it was not possible to determine the effects of exercise timing on vaccine responses. Study two investigated whether the antibody response to influenza vaccination was influenced by the intensity of eccentric exercise. Three groups exercised at an intensity eliciting 60%, 85% or 110% of one repetition maximum, and the antibody responses at 28 days post-vaccination were compared to those from a resting control group. In the exercise groups, both men and women showed enhanced antibody responses against the B/Florida strain, and men had enhanced responses against A/Uruguay, in comparison to resting controls. In both cases, the control group exhibited poorer responses against these strains, but no effect of exercise intensity was observed. Study three investigated whether the site of vaccine administration affected the efficacy of the immune response to hepatitis B vaccination following eccentric exercise. The antibody seroconversion rate to the vaccine was low (approx. 5 %), and thus, further analysis between exercise and control participants was not feasible. In sum, supporting previous research, it appears that acute eccentric exercise can enhance the immune response to poorly immunogenic strains of influenza, but research is needed to establish if exercise can enhance other poorly immunogenic vaccines, or vaccine responses in the immuno-compromised.
143

Caveolin-1 in renal disease

Chand, Sourabh January 2017 (has links)
Renal disease is a major global public health issue that affects 10% of the general population with premature morbidity and mortality related to cardiovascular disease and infection. Interstitial fibrosis is a common hallmark of progressive kidney dysfunction. There remains a stubborn discrepancy in identifying which patients suffer adverse events because of their disease or resulting treatment. Investigation in patient genome variation may explain this discrepancy. Caveolin-1 is the essential structural protein for caveolae that are ubiquitously distributed in fibroblasts, endothelial and epithelial cells. They act as molecular chaperones for transcellular signaling such as degradation of the activated TGFβ-1 receptor. In this thesis, caveolin-1 single nucleotide polymorphism rs4730751 CC genotype is shown to be associated with a better outcome in renal patients for arterial stiffness, and reduced mortality from cardiovascular disease, infection, malignancy in ANCA associated vasculitis. By inducing renal models of fibrosis in caveolin-1 knockout mice, deletion of caveolin-1 leads to increased fibrosis. In conclusion, this polymorphism could be used as a marker of disease risk either in isolation or as part of a clinical risk score to counsel patients on the likely prognosis of their condition. Manipulation of caveolin-1 expression may be a therapeutic strategy in reducing renal fibrosis.
144

Defining the mechanism(s) of Hepatitis C virus (HCV) entry

Schwarz, Anne-Katrin January 2009 (has links)
Hepatitis C virus (HCV) is a major human pathogen and the leading cause of cirrhosis and liver cancer worldwide. HCV entry is clathrin- and pH-dependent, and requires CD81, Scavenger receptor BI (SR-BI), and the tight junction (TJ) proteins Claudin-1 and Occludin. Primary HCV strains cannot be efficiently cultured in vitro, making the evaluation of potential antiviral compounds in a biologically relevant context extremely difficult. Despite being suitable for high-throughput screening, most cell-based reporter assays rely on the secretion of serine alkaline phosphatase and thus do not allow the selection of HCV infected cells, or the screening of patient samples to identify cell culture infectious viral strains. We aimed to develop a cell-based reporter assay, which utilizes the viral NS3/4A protease to cleave and activate a fluorescent reporter protein constitutively expressed in Huh-7.5 hepatoma cells. HCV tropism is restricted to the liver, where hepatocytes are polarized and form TJ, which are indispensable for normal liver functionality. We demonstrate that in confluent cells, SR-BI and Claudin-1 expression is increased and that HCV entry is enhanced when cellular contact is established. Furthermore, cell junction formation and SR-BI overexpression, respectively, accelerated virus entry, suggesting a key role for SR-BI in HCV internalization. The mechanisms underlying HCV-associated hepatic injury are poorly understood, however, it is thought that HCV may disrupt TJ integrity, thus compromising hepatocyte polarity and function. We demonstrate that the HCV structural proteins modulate the expression and localization of TJ proteins, leading to their redistribution to cytoplasmic vesicles with possible consequences for TJ integrity in vivo.
145

Student nurses, stigma and infectious diseases : a mixed methods study

Ashby, Nichola Jane January 2016 (has links)
Individuals or groups will form impressions of another based upon a series of traits, which may be relied upon when forming behaviour pattern towards others (Asch, 1946; Crocker and Major, 1989; Pinel, 1999; Albon, 2002; Corrigan and Wassel, 2008). These traits will depict the reception individuals receive within healthcare and may depend upon learnt and inherited ‘perceived’ ideals affecting the working and personal relationships experienced by positively diagnosed healthcare workers, predisposing stigma responses to others (Asch, 1946). A mixed method study investigating the potential existence of stigmatising values from student nurses towards positively diagnosed healthcare workers with Pulmonary Tuberculosis (PTB), Human Immunodeficiency Virus (HIV), Methicillin-resistant Staphylococcus Aureus (MRSA), Hepatitis C and Diabetes type 2, was undertaken. Analysis provided exploration of the stigmatising attitudes and values of 482 student nurses undertaking an education programme. Interpretation of the findings explored the participants views at course commencement, midpoint and completion considering variables of education (theoretical and clinical), personal and professional influences. Findings indicated that stigmatising values and attitudes return to those identified precourse and underpin the need for implementation of a change to nurse education within this area. The development of a longitudinal education model for healthcare workers considering disease processes and influencing factors psychologically, socially and physically, will provide opportunities to reduce the existence of stigmatisation for positively diagnosed healthcare workers.
146

Investigation of the role of neutrophils in the production of autoantigens in patients with rheumatoid arthritis

Spengler, Julia January 2016 (has links)
In most patients with rheumatoid arthritis (RA), citrullinated autoantigens are targeted by autoantibodies (ACPA). However, the process leading to protein citrullination by peptidylarginine deiminases (PADs) in the joint remains unclear. In this thesis, I tested the hypothesis that generation of neutrophil extracellular traps (NETosis), can contribute to release of enzymatically active PADs and citrullinated autoantigens in inflamed joints. I have shown that in vitro induced NETosis leads to release of citrullinated proteins and enzymatically active PADs both attached to NETs and free in the supernatant. In the SF from RA patients DNA levels correlated with neutrophil concentrations, and DNA levels and PAD activity were found to be increased compared with OA patients. Finally, I demonstrated the antigenicity of in vitro generated NETs and identified citrullinated histone H3 as a NET-component recognised by ACPA and RA sera. Based on the findings in this thesis release of active PADs into SF by neutrophil cell death is a plausible explanation for the generation of citrullinated extracellular autoantigens. In ACPA positive RA patients the continuous production of these autoantigens combined with pre-existing ACPA may result in the formation of immune complexes and perpetuation of the inflammatory response.
147

Systematic reviews and meta-analyses of test accuracy : developing methods that meet practitioners' needs

Davenport, Clare Frances January 2012 (has links)
Testing can be a substantial driver of health care costs. Increase in test use over recent decades has occurred despite disappointing results from test accuracy evaluations. Poor quality and reporting of primary test accuracy studies and difficulties with understanding and application of test accuracy information are purported to be important contributors to this observed evidence ‘gap’. The objectives of this thesis were to: * Systematically review evidence concerning the understanding and application of test accuracy metrics. * Undertake primary research building on the review of understanding and application. * Assess whether the contribution of test accuracy reviews to the test accuracy evidence base is compromised by deficiencies in their contextual fit, or of included primary studies. Existing research concerned with understanding and application of test accuracy information is not driven by the needs of decision makers. Contrary to the prevailing view in the literature, findings of original research from this thesis demonstrate that probability revision is not a feature of diagnostic decision making. Choice of test accuracy metric however was shown to have a profound influence on diagnostic decision making. Deficiencies in question formulation and contextualisation of test accuracy reviews are undermining their contribution to the test accuracy evidence base.
148

Cannabis use amongst individuals with severe mental health problems : reasons for use and motivational based interventions

Cook, Adam January 2011 (has links)
Motivational based approaches have been shown to be effective in reducing problematic behaviours in the general population. The present study reviewed 31 studies that aimed to reduce a number of problematic behaviours amongst individuals with severe mental health problems. Evidence supporting the efficacy of motivational based approaches in increasing adherence to medication was inconsistent. In the minority of studies where an increase in medication adherence was reported, the duration of effect appeared to decline over time. The evidence from the studies that aimed to reduce substance use was more consistent. A number of other positive outcomes were reported reductions in: dependence, general functioning and mental health symptomatology. The empirical paper presents a quantitative study that aimed to look at the reasons for cannabis use amongst individuals with and without severe mental health problems. It was found that the motivations for using cannabis did not differ between the two groups; both using cannabis to cope with negative affect, for pleasure and for social reasons. However, individuals with severe mental health problems differed in that they expected cannabis to be more ‘socially and sexually facilitative’. Irrespective of mental health status, participants who used cannabis more problematically endorsed more coping and pleasure motives.
149

Childhood obesity and its prevention in primary school-aged children : a focus on South Asian communities in the UK

Pallan, Miranda Jane January 2011 (has links)
Childhood obesity is a major global concern but there is little evidence for effective childhood obesity prevention strategies. People of South Asian origin are a specific target group for obesity prevention as they are vulnerable to cardiovascular health effects of obesity. This thesis explores the contextual influences on the development of childhood obesity by presenting two studies; a quantitative analysis of routine datasets explores the association between the school physical activity environment and obesity in children, and a qualitative study explores the beliefs of South Asian community members and other stakeholders about the causes of childhood obesity and potential interventions to prevent it. A process of development of a childhood obesity prevention programme tailored to South Asian communities, guided by the MRC framework for complex interventions is described. The contextual information from the stakeholder focus groups is central to this process. Finally, this thesis examines the potential consequences of obesity in South Asian children by exploring its association with body image. Understanding the psychosocial consequences of obesity in target communities will enable future interventions to be appropriately designed. The findings of this thesis highlight the importance of understanding the cultural context with respect to childhood obesity causes, consequences and intervention.
150

The family in flux : a mixed methods study on men's experiences of antenatal genetic screening

Dheensa, Sandi January 2012 (has links)
Women’s views of antenatal screening have been widely researched, but men’s remain under-explored. The original contribution of this research was to conduct a mixed-methods study about men’s experiences specifically. In-depth interviews were firstly conducted with twelve men. Six women were interviewed about their views on men’s involvement. A grounded theory was developed, which was that men began developing a prenatal paternal identity and a schema of their child. These conceptualisations were reinforced or distorted by screening, causing their ideas and feelings about their growing family to be in a state of flux. To explore this theory with a more diverse group, a questionnaire was designed, pretested (n=30), piloted (n=53) and administered to 200 men. Exploratory factor analysis showed prenatal paternal identity and child-schema consisted of ‘bonding and closeness’, ‘genetic relationship’ and ‘imagined interactions’. Regression analyses showed investing time in screening, seeing more ultrasound scans, and making screening decisions, predicted higher scores on ‘bonding and closeness’. Investing time and being younger predicted higher scores on ‘genetic relationship’. Investing time, feeling fetal movements, being of a higher socioeconomic status and being younger predicted higher scores on ‘imagined interactions’. Longitudinal research is now required to identify implications for men, women and children.

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