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The majority of gymnasts are young girls. Training hours required to meet competition demands are high and gymnasts begin serious training at a young age. Concerns regarding injury risk are substantial and may be the result of repeated high impact loads experienced during landings from dismounts, tumbling and vaulting. There is currently little information available to coaches regarding the quantity of training that is safe or not safe. The use of acceleration was tested for its efficacy for use in the field to examine risk factors for injury. Risk factors examined were loading and fatigue. Kinematics, ground reaction forces and acceleration were measured during landing from gymnastics skills and also pre- and post fatigue during landing from a vertical jump and a 35cm drop in the laboratory. A pilot study was performed in the field to examine accelerations during gymnastics skills pre- and post-training. Lower body kinematics of landing were notably different between gymnastics skills analysed. Joint positions at touchdown and range of motion available during landing due to these joint positions affect the ability to contribute to energy absorption. Peak ground reaction forces and peak accelerations measured at the pelvis showed significant differences between skills landing on both the hands and the feet. The peak acceleration during landing from gymnastics skills was positively correlated with the peak ground reaction force. A large variability stiffness during landing meant that an estimation of ground reaction force using simple modelling was not successful in improving the correlation. After a fatiguing jumping and landing task peak accelerations measured at the pelvis during landing were increased indicating the use of acceleration for identifying fatigue. Pilot field testing of acceleration during landing from gymnastics skills showed similar results to laboratory results. Pre- and post-training measurements showed no difference in peak accelerations during landing from the skills analysed. The training session completed was not demanding enough to induce enough fatigue to be seen in acceleration values Acceleration has potential to be used to quantify repeated loading and accumulative effects in gymnastics, as well as the presence of fatigue in gymnasts during training sessions.

It has been demonstrated that 1,25 dihydroxy vitamin D3 (1,25 (OH)2VD3) can inhibit the proliferation of cancer cells including colorectal and hepatocellular cells which are mainly responsible for liver cancer. However, the use of 1, 25 (OH)2VD3 is hampered due to the development of hypercalcaemia. Current treatment using hepatic arterial delivery of drug solution is inconvenient since repetitive invasive treatments are required. This work aims to tackle this problem by utilizing crosslinked microspheres prepared by suspension polymerization as a carrier to control the release of 1, 25 (OH)2VD3 or hydrophobic drug in general at targeted sites over a long period. Poly(vinyl neodecanoate crosslinked ethyleneglycol dimethacrylate) microspheres in the size range of 35 m were prepared via suspension polymerization. Different parameters in suspension polymerization such as temperature, concentration and crosslinker percentage were studied in details. The effect of stabilizer on the formation of spheres was carefully investigated by using RAFT polymerization to produce various structures of the stabilizer, poly (vinyl pyrrolidone). Core- shell microspheres were also produced to enhance the hydrophilicity of the surface of microspheres. Hydrophobic drugs were loaded to these microspheres after reaction by the evaporation method. These microspheres were then used for drug loading and drug release study. Release study has shown that up to 10% of drug was released after 40 days. Cytotoxicity test reveals the suitability of this polymer for application in biomedical field. The MTT assay of Clofazimine loaded microspheres on the colorectal cancer cell lines HT29 has shown that the cell number was decreased about 50% after drug treatment.

It has been demonstrated that 1,25 dihydroxy vitamin D3 (1,25 (OH)2VD3) can inhibit the proliferation of cancer cells including colorectal and hepatocellular cells which are mainly responsible for liver cancer. However, the use of 1, 25 (OH)2VD3 is hampered due to the development of hypercalcaemia. Current treatment using hepatic arterial delivery of drug solution is inconvenient since repetitive invasive treatments are required. This work aims to tackle this problem by utilizing crosslinked microspheres prepared by suspension polymerization as a carrier to control the release of 1, 25 (OH)2VD3 or hydrophobic drug in general at targeted sites over a long period. Poly(vinyl neodecanoate crosslinked ethyleneglycol dimethacrylate) microspheres in the size range of 35 m were prepared via suspension polymerization. Different parameters in suspension polymerization such as temperature, concentration and crosslinker percentage were studied in details. The effect of stabilizer on the formation of spheres was carefully investigated by using RAFT polymerization to produce various structures of the stabilizer, poly (vinyl pyrrolidone). Core- shell microspheres were also produced to enhance the hydrophilicity of the surface of microspheres. Hydrophobic drugs were loaded to these microspheres after reaction by the evaporation method. These microspheres were then used for drug loading and drug release study. Release study has shown that up to 10% of drug was released after 40 days. Cytotoxicity test reveals the suitability of this polymer for application in biomedical field. The MTT assay of Clofazimine loaded microspheres on the colorectal cancer cell lines HT29 has shown that the cell number was decreased about 50% after drug treatment.

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The behaviour of sands during loading has been studied in great detail. However, little work has been devoted to understanding the response of sands in unloading. Drained triaxial tests indicate that, contrary to the expected elastic behaviour, sand often exhibit contractive behaviour when unloaded. Undrained cyclic simple shear tests show that the increase in pore water pressure generated during the unloading cycle often exceeds that generated during loading. The tendency to contract upon unloading is important in engineering practice as an increase in pore water pressure during earthquake loading could result in liquefaction. This research contributes to filling the gap in our understanding of soil behaviour in unloading and subsequent reloading. The approach followed includes both theoretical investigation and numerical implementation of experimental observations of stress dilatancy in unload-reload loops. The theoretical investigation is done at the micromechanical level. The numerical approach is developed from observations from drained triaxial compression tests. The numerical implementation of yield in unloading uses NorSand — a hardening plasticity model based on the critical state theory, and extends upon previous understanding. The proposed model is calibrated to Erksak sand and then used to predict the load-unload-reload behaviour of Fraser River sand. The trends predicted from the theoretical and numerical approaches match the experimental observations closely. Shear strength is not highly affected by unload-reload loops. Conversely, volumetric changes as a result of unloading-reloading are dramatic. Volumetric strains in unloading depend on the last value of stress ratio (q/p’) in the previous loading. It appears that major changes in particles arrangement occur once peak stress ratio is exceeded. The developed unload-reload model requires three additional input parameters, which were correlated to the monotonic parameters, to represent hardening in unloading and reloading and the effect of induced fabric changes on stress dilatancy. The calibrated model gave accurate predictions for the results of triaxial tests with load-unload-reload cycles on Fraser River sand. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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