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Most reinforced concrete (RC) structures are continuous in some way, and many of these structures are strengthened using fibre-reinforced polymer (FRP) materials as a routine basis. The problem of how to exploit moment redistribution in FRP-strengthened continuous RC structures is still unresolved. Reduction in ductility has been recognised in such structures. However, FRP-strengthening is introduced as an effective method to enhance the strength and load bearing capacity of RC structures. As a result, design guidelines worldwide employ conservative guidance for design, such that they limit the potential exploitation of moment redistribution in FRP-strengthened members. To date, limited research has been conducted into the redistribution of bending moment in such structures. Previous theoretical studies have not yet led to a reliable and rigorous solution for quantifying moment redistribution throughout the loading cycle. In addition, a wide scatter of moment redistribution percentage findings, from zero to 56%, has been reported in previous experimental studies. This demonstrates the need for further research to effectively characterise the circumstances under which moment redistribution can be relied on, both into and out of FRP-strengthened zones in continuous RC flexural members. This research aims to encourage the use of FRP for strengthening existing RC structures in a more efficient manner. The findings help to better understand restrictions on moment redistribution into and out of FRP-strengthened zones, effect of mechanical anchorage of the FRP on the degree of moment redistribution, and the extent to which moment redistribution can be relied on. A new analytical model, only based on structural mechanics, is developed in this research. A comprehensive set of large-scale structural testing is undertaken to validate the analytical model under various strengthening circumstances. The analytical and experimental results show that moment redistribution can occur into FRP-strengthened zones to full capacity without any limitation, even if the FRP is unanchored. Further, bending moment can also be redistributed out of strengthened zones to a considerable extent (up to 20%), depending on the quantity and stiffness of the FRP, and provided that the FRP is fully anchored. A set of parametric studies is conducted to investigate the effectiveness of different parameters on the level of moment redistribution. The major parameters include compressive strength of concrete, steel reinforcement proportion, steel yield strength, FRP quantity and stiffness, ultimate strain of the FRP, strengthening configuration, load position, beam shape, and curvature ductility. The outcomes demonstrate that it is not only the curvature ductility of FRP-strengthened sections that is important to the capacity for moment redistribution (out of such zones), but also the mode of failure, strength of the other critical zones, the ratio of stiffness between the critical zones, and the loading arrangement. It is concluded that moment redistribution in continuous FRP-strengthened concrete structures should be permitted both into and out of strengthened zones, provided that the criteria for such redistribution are met.

Increased lipid peroxidation is thought to play an important role in the pathogenesis of atherosclerosis. However, such elevation in lipid peroxidation has been difficult to assess because specific and reproducible methods for the measurement of products of lipid peroxidation have been unavailable. The aim of this thesis is to show the development of a simple and reliable method to measure of plasma hydroperoxides, initial products formed during peroxidation of unsaturated lipids (e.g. fatty acids and cholesterol). Using this as an index of oxidative injury in vivo, I have shown that it feasible to measure plasma hydroperoxides using Ferrous Ion Oxidation in Xylenol Orange (FOX) version 2. The assay is based upon the oxidation of ferrous to ferric ions by hydroperoxides under acidic conditions. The generated ferric ion is complexed by the ferric ion indicator xylenol orange yielding a blue-purple complex with an absorbance maximum at 550-600 nm. Authentic plasma hydroperoxides are determined by a strategy in which the specific hydroperoxide reductant, triphenylphosphine, is used to discriminate between the background signal generated by ferric ions present in plasma and that generated by hydroperoxide in plasma. The method is specific and sensitive; detection limit <1.0 μM. Inter- and intra assay coefficients of variation are (<5%). Intra laboratory coefficient of variation is <10%. Using this assay, I have shown that plasma hydroperoxides were elevated in individuals with non-insulin-dependent diabetes mellitus (NIDDM) (9.4 ± 3.5 μM;(n=110) compared to those in healthy controls (3.9 ± 2.2 μM; n=60). Relationships between measures of plasma oxidation, metabolic control and selected complication in NIDDM and location of plasma hydroperoxides are discussed with relevance to atherosclerosis.

Much evidence indicates that maternal obesity programs a range of complications in offspring, highlighting the need to identify beneficial interventions. The present thesis examined if the programmed effects of maternal obesity on offspring are exacerbated by exposure to a high-fat, high-sugar ‘Cafeteria’ (Caf) diet and investigated the effects of a healthy diet intervention in adulthood. The first study examined whether a diet switch intervention could reverse the adverse effects of an unhealthy postweaning diet in male and female rat offspring born to dams fed standard chow or a high-fat, high-sugar, Caf diet. Weanling offspring from Caf dams were smaller and lighter, yet had more retroperitoneal (RP) fat, particularly in males. Maternal obesity enhanced the impact of postweaning Caf exposure on adult (14-week-old) body weight, RP fat, liver mass and plasma leptin in males but not females. Maternal Caf diet significantly increased relative expression of ACACA and Fasn in male and female weanling liver, whereas PPARα was increased in males from Caf dams. Hepatic CPT-1 expression was reduced in adult males from Caf fed dams. The results underline the sex-specific detrimental effects of maternal obesity on offspring; maternal obesity exacerbated the obesogenic phenotype produced by postweaning Caf diet in male, but not female offspring. A subset of rats from this first cohort were maintained on their postweaning diets until 22 weeks of age, when postweaning Caf groups were switched to chow for a further 5 weeks. Switching from Caf to chow in adulthood suppressed energy intake below groups maintained on chow. Consequently, body weight and adiposity fell in switched groups, but remained significantly higher than chow-fed controls. The diet switch improved a deficit in place recognition memory observed in Caf-fed groups, with no significant change over time in chow-fed groups. Importantly, the effects of the switch did not differ between offspring born to chow or Caf-fed dams. Thus, in these older adult offspring a healthy dietary intervention led to benefits regardless of prior exposure to maternal obesity. To complement these data, our second study investigated if the programming effects of maternal obesity were aggravated by offspring exposure to a Caf diet when introduced in adulthood. Male and female offspring from lean and obese dams were weaned onto chow until 9 weeks of age; siblings were then either continued on chow or switched to Caf diet for 5 weeks. Offspring from Caf dams were smaller than those from chow dams at birth, and exhibited greater adiposity, plasma glucose and leptin levels at weaning in both sexes. Offspring of Caf dams exhibited elevated liver triglyceride content at weaning but no significant changes in the liver antioxidant enzymes GPx, SOD, and CAT. The switch to Caf diet elevated body weight and fat mass, with more pronounced effects in females than males. As in our first study, adult males (14 week old) from Caf-fed dams exhibited increased body weight, adiposity, and plasma insulin and leptin levels relative to offspring from chow dams. In female offspring, only RP fat mass and plasma insulin were increased by maternal obesity. Moreover, there were behavioural effect of maternal obesity (reduced anxiety-like behaviour) on offspring. Thus, the effects of maternal Caf diet exposure were absent until a cafeteria diet challenge in adulthood, indicating that Caf diet-induced maternal obesity programs a latent vulnerability to obesogenic diet exposure in offspring, particularly in males. Further studies are needed to investigate the beneficial effects of reprogramming strategies such as healthy diet intervention in offspring, which are likely to be influenced by the duration, timing and mode of intervention.