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Atmospheric CO enrichment is a key factor contributing to global climate 2 change. Major consequences of climate change include increasing sea surface temperature and decreasing seawater pH (ocean acidification) – both of which are predicted to lead to an increase in ocean hypoxic events. Early ontogenetic stages of invertebrates have shown sensitivity to these environmental changes. Previous research has focused on short-term exposure to these environmental factors; however, the long- term and multi-generational effects of ocean acidification on organismal reproduction and development have received little attention. The aim of this thesis is to address this shortcoming for reproduction and early embryonic development of the economically- and ecologically-important sea urchin, Paracentrotus lividus (Lamark, 1816) and the reef-forming invasive polychaete, Ficopomatus enigmaticus (Fauvel, 1923). Fertilisation success and early embryogenesis of P. lividus were negatively impacted under conditions of increased pCO, at ambient temperature and ambient 2 +2°C after 12 months exposure. Sperm motility – determined by computer assisted sperm analysis (CASA) – showed a significant increase in average swimming speed measured as curvilinear velocity (VCL) at increased pCO levels after 6 months but by 2 12 months VCL values had decreased. There was no overall significant effect of pCO 2 on VCL but there was a significant reduction in fertilisation success under hypoxic conditions. Increasing pCO levels appeared to buffer the effects of hypoxia, however, 2 with significantly lower fertilisation success observed only under hypoxic conditions at ambient pCO. Multi-generational experiments examined the effects of increased pCO on 2 F.enigmaticus. Both percentage sperm motility and sperm VCL were similar between experimental treatments, but there was a significant difference between generations 0 and 2. In contrast, fertilisation success was negatively affected by both pH and generation, with a significant reduction seen with pH at all generations and a significant reduction seen between generation 0 and generation 2. Oocyte diameter was also significantly affected by pH and generation, with a significant increase in egg diameter seen at generation 1 in all pH treatments except pH 7.95, which shows a significant increase and generation 2, which suggests differing levels of maternal investment. This research suggests that in the long term, ocean acidification, temperature and hypoxia may seriously impact the reproduction and development of two important marine invertebrate species. This research highlights the need for further long-term investigation involving multiple stressors to provide a more comprehensive understanding of the long-term effects arising from changing oceanic chemistry.

This research examines the impact of work-family reconciliation policies on gender inequality in the labour market, and on the division of paid work and care in the household. Policies designed to help families meet their work and care responsibilities have undergone considerable reform over the last fifteen years. The research aims to understand how this has affected the way that earning and caring are divided between mothers and fathers, and the implications of this for mothers’ labour market outcomes. The research compares two cohorts; the National Child Development Study (NCDS) tracks individuals born in 1958, and the British Cohort Study (BCS) those born in 1970. These cohorts experienced the key childbearing years of their early thirties on either side of a fairly sharp discontinuity in work-family reconciliation policy. The research aims to link this difference in policy environments to differences the way that couples in each cohort divide paid work and care, and in the labour market behaviour of mothers and the penalties they face when they are in employment. Logistic regression models are employed to quantify the magnitude and significance of the impact of cohort membership on the work and care outcomes of interest, controlling for other variables that affect these outcomes. Some case-level analysis of the data is also carried out; individuals representing typical family arrangements are highlighted, to demonstrate the relevance of the theoretical model and assist with hypothesis generation. Case stories illustrate the interplay of individual circumstances with policy and other external factors, in a way that is difficult to achieve using statistical methods. A key finding is that the younger cohort is less likely to report equal sharing of childcare than the older cohort, even after controlling for other factors that might influence the division of labour. This is also in spite of the finding that mothers in the younger cohort are more likely to be in work. This suggests progress to some extent, in that mothers perhaps find it easier to be in employment. However at the same time it represents a regressive step at the household level, as they not only continue to shoulder the majority of the care work, but are even more inclined to do so. Analysis of pay and status gaps also yields interesting results. The findings suggest that the penalty to motherhood in terms of labour market status accrues by virtue of the interrupted human capital accumulation that results from periods out of the labour market or working part time. However, the motherhood penalty in pay persists even after controlling for other wage determinants, suggesting that these gaps are a direct result of motherhood itself and not of the labour market behaviour changes that occur as a result. The research contributes theoretically and substantively to the wider literature on this topic. It brings together human capital perspectives with theories of gender, power and resources, and of the impact of policy on family life, and uses Amartya Sen’s capability approach to reconcile and move forward these ideas. It also contributes to the practical understanding of the impact of policy on the way that families reconcile work and care, and in particular the implications of policy for gender equality. Finally, its methodological contribution is in the use of a narrative approach to large-scale quantitative data, alongside more conventional statistical techniques, in order to further exploit the detailed, longitudinal data available.

Many methods exist in the literature for the prediction of pharmacokinetic parameters which describe drug distribution in rat and human, such as tissue-to-plasma partition coefficients (Kps) and volume of distribution (Vss). However, none of these methods make use of the in vivo information obtained at the early stages of the drug development process in the form of plasma concentration vs. time profiles. The overall aim of the presented study was to improve upon an existing Kp prediction method by making use of the distribution information contained within this experimental data. Chapter 2 shows that Kp values can be successfully obtained experimentally, but that this process is expensive and time-consuming. Chapter 3 compares six Kp prediction methods taken from the literature for their ability to predict the Kp values of 80 drugs. The Rodgers et al. model was found to be the most accurate, with over 77% of predictions within 3-fold of experimental values. This Chapter also discusses the Vss prediction ability of some of these methods, with the Poulin & Theil and Rodgers et al. models shown to be the most accurate predictors for rat Vss and human Vss respectively. Chapter 4 investigates the relationship between muscle Kp and the Kps of all other tissues, to show that experimental muscle Kp can be used as a surrogate from which all other non-adipose Kp values can be predicted. However, the predictions made using this method were shown to be less accurate than predictions made by the Rodgers et al. model for the same dataset of drugs. A relationship was identified between muscle Kp and tumour Kp in rat, suggesting a potential way to predict tumour Kp in the future. In Chapter 5, a novel method is developed whereby Kp predictions made by the Rodgers et al. model are updated using prior information obtained from the in vivo concentration-time profile. These updated values are then used within a physiologically-based pharmacokinetic (PBPK) model and are shown in Chapter 6 to generate improved predictions for other pharmacokinetic parameters such as Vss and clearance in both rat and human. 100% of human Vss predictions made by the most accurate of the novel methods presented here were within 3-fold of experimental values, compared to 68.8% of predictions made by the Rodgers et al. model. The work presented here has highlighted the need for a more accurate method for the prediction of Kp values, and has addressed this need by generating a model which improves upon the most accurate Kp prediction method currently found in the literature. This will lead to an increase in confidence in the use of predicted pharmacokinetic parameters within PBPK modelling.

Collagen fibrils, which are large, multicomponent protein assemblies, are the principal source of mechanical strength in animal tissues and can grow to millimetre lengths. The mechanism of fibril formation and the influence of non-collagenous components, particularly proteoglycans, in the hierarchical assembly and organisation of collagen fibrils have yet to be fully determined. In this study, quantitative mass mapping by scanning transmission electron microscopy of entire tendon fibrils showed that some fibrils exhibited thinned regions. The axial mass distributions (AMDs) corresponding to the thinned regions were smooth and linear troughs in mass, consistent with the fusion of two fibril tips. In addition, fusion of entire fibrils isolated from tissue has been induced in vitro for the first time. Tissue fibrils fused at their tips in buffered solution to form either fibril rings (having no ends) or elongated fibrils with thinned regions, which lends support to the hypothesis that fusion of fibril tips can occur and that fusion is a mechanism of fibril elongation during the organisation of the extracellular matrix of tendon. Negative staining showed that fusion occurred between the N-tip of a unipolar or bipolar fibril and the C-tip of a unipolar fibril. Fusion between two N-tips was not observed. In one instance fusion was seen between the C-ends of two unipolar fibrils, indicating that fusion between fibril tips must involve the C-end of a unipolar fibril. Cuprolinic blue staining of intact fibrils localised surface-bound proteoglycans predominantly to the shaft region, with markedly depleted levels at the tips. After enzymic removal of proteoglycans, fibrils aggregated laterally in solution. It is likely that a threshold surface concentration of proteoglycans on the fibril shaft prevents lateral aggregation of fibrils whilst being permissive of fibril elongation by tip-to-tip fusion in vivo. Immunoprecipitation experiments with cultured skin fibroblasts using anti-decorin antibodies and anti-collagen antibodies demonstrated the presence of procollagen-decorin complexes in the cell media, suggesting that decorin (a small proteoglycan found in collagen-rich tissues) binds procollagen prior to fibril assembly. This thesis shows that a relationship exists between collagen and proteoglycans throughout the hierarchical assembly of collagen fibrils. An early step in the formation of fibrils appears to be the assembly of procollagen-proteoglycan complexes, which subsequently assemble into well-defined early fibrils. The early fibrils fuse at their tips to form elongated fibrils and the fusion is regulated by proteoglycans located on the fibril shafts.