Trauma caused by grasping during laparoscopic surgery is something which will never be fully eradicated however efforts should be taken to reduce the potential to cause trauma by grasping. Tissue is often grasped with excessive forces for long periods of time during surgeries such as cholecystectomies and colectomies. This along with failed grasping actions and the occurrence of slip has been shown to damage the tissue. Design features often employed within graspers such as profiling and the occlusion mechanism of the instrument cause areas of high, uneven distribution of pressures on the tissue which can result in perforation or tissue tearing. By investigating these contributing factors, development of graspers with a low risk to cause damage this combined with actuating the grasping force should reduce the incidence of grasping trauma, currently at estimated at one incidence per procedure. These trauma events can lead to conversion to open surgery, peritonitis and even death. Development of an autonomous grasping instrument to detect and prevent slip by actuating the grasping force is reported. Piezoelectric sensors are used to detect incipient slip and slip events. A closed loop control system then reacts to these perceived slip events to prevent slip occurring by actuating the applied force by small increments to increase or decrease grasping force. This leads to a system in which only the required amount of force necessary to overcome pull force is applied to the tissue. Other areas of investigation to reduce tissue trauma are presented. In chapter 3 design features such as surface profiling and fenestrations are evaluated to determine the potential to cause damage. A variety of profiles and fenestrations are studied and each is reported by representing the applied force to retention force ratio which indicates how good the profile is at retaining tissue against a pull force. The aim of this study was to develop surface profiling which had a high retention force but a reduced number of high stress areas which can lead to tissue damage. Three new parallel action grasping designs are presented and evaluated using finite element analysis. Parallel action grasping is important in reducing tissue trauma as it distributes pressure evenly across the active grasping area as opposed to more conventional pivot style graspers which have high stress concentration areas in the proximal opening. Each area of study within the thesis addresses areas of concern which have been shown to cause tissue trauma and postulates viable solutions to reduce the incidences of tissue trauma during laparoscopic surgery with the ultimate aim of developing a deployable and autonomous grasping device which will detect and prevent slip.

L'efficacité énergétique du bâtiment occupe une place importante dans les projets de construction. La façade, intermédiaire entre l'environnement et l'intérieur, joue un rôle clé pour déterminer les performances énergétiques du bâtiment. Les systèmes de fenestration complexes sont généralement utilisés pour améliorer son efficacité. L'étude des performances de la façade inclut généralement la consommation d'énergie, l'éclairage naturel et les aspects de confort visuel et thermique. Les efforts récents s'orientent vers l'utilisation de modèles intelligents tels que le Building Information Modeling. CFS pourraient être facilement comparées dans la phase de conception du bâtiment afin d'optimiser ses performances. Nous présentons une méthodologie pour transformer le modèle architectural du BIM en modèle énergétique ainsi que des modèles optique et thermique du CFS compatibles avec le BIM. Ces modèles sont validés par une comparaison avec des données expérimentales et les normes actuelles. / The energy efficiency of the building occupies an important place in construction projects. The facade plays a key role in determining the performance of the building. Complex fenestration systems (CFS) are therefore generally used to improve its efficiency. The facade's performance evaluation usually includes energy consumption, natural lighting, visual and thermal comfort aspects in order to choose the optimal CFS. Recent efforts have focused on using rich models such as Building Information Modeling (BIM). These models provide an opportunity for automation and cost savings. Several CFS models could easily be compared to optimize the building's performance. In this thesis, we present a methodology to transform the architectural model of the BIM into a Building Energy Model compatible with several simulation software. We also present optical and thermal models compatible with BIM. These models are validated by comparison with experimental data and current standards.

Doctor of Philosophy(PhD) / Owing to its strategic position in the liver sinusoid, pathologic and morphologic alterations of the Liver Sinusoidal Endothelial Cell (LSEC) have far-reaching repercussions for the whole liver and systemic metabolism. LSECs are perforated with fenestrations, which are pores that facilitate the transfer of lipoproteins and macromolecules between blood and hepatocytes. Loss of LSEC porosity is termed defenestration, which can result from loss of fenestrations and/ or decreases in fenestration diameter. Gram negative bacterial endotoxin (Lipopolysaccharide, LPS) has marked effects on LSEC morphology, including induction LSEC defenestration. Sepsis is associated with hyperlipidemia, and proposed mechanisms include inhibition of tissue lipoprotein lipase and increased triglyceride production by the liver. The LSEC has an increasingly recognized role in hyperlipidemia. Conditions associated with reduced numbers of fenestrations such as ageing and bacterial infections are associated with impaired lipoprotein and chylomicron remnant uptake by the liver and consequent hyperlipidemia. Given the role of the LSEC in liver allograft rejection and hyperlipidemia, changes in the LSEC induced by LPS may have significant clinical implications. In this thesis, the following major hypotheses are explored: 1. The Pseudomonas aeruginosa toxin pyocyanin induces defenestration of the LSEC both in vitro and in vivo 2. The effects of pyocyanin on the LSEC are mediated by oxidative stress 3. Defenestration induced by old age and poloxamer 407 causes intrahepatocytic hypoxia and upregulation of hypoxia-related responses 4. Defenestration of the LSEC seen in old age can be exacerbated by diabetes mellitus and prevented or ameliorated by caloric restriction commencing early in life

Doctor of Philosophy(PhD) / Owing to its strategic position in the liver sinusoid, pathologic and morphologic alterations of the Liver Sinusoidal Endothelial Cell (LSEC) have far-reaching repercussions for the whole liver and systemic metabolism. LSECs are perforated with fenestrations, which are pores that facilitate the transfer of lipoproteins and macromolecules between blood and hepatocytes. Loss of LSEC porosity is termed defenestration, which can result from loss of fenestrations and/ or decreases in fenestration diameter. Gram negative bacterial endotoxin (Lipopolysaccharide, LPS) has marked effects on LSEC morphology, including induction LSEC defenestration. Sepsis is associated with hyperlipidemia, and proposed mechanisms include inhibition of tissue lipoprotein lipase and increased triglyceride production by the liver. The LSEC has an increasingly recognized role in hyperlipidemia. Conditions associated with reduced numbers of fenestrations such as ageing and bacterial infections are associated with impaired lipoprotein and chylomicron remnant uptake by the liver and consequent hyperlipidemia. Given the role of the LSEC in liver allograft rejection and hyperlipidemia, changes in the LSEC induced by LPS may have significant clinical implications. In this thesis, the following major hypotheses are explored: 1. The Pseudomonas aeruginosa toxin pyocyanin induces defenestration of the LSEC both in vitro and in vivo 2. The effects of pyocyanin on the LSEC are mediated by oxidative stress 3. Defenestration induced by old age and poloxamer 407 causes intrahepatocytic hypoxia and upregulation of hypoxia-related responses 4. Defenestration of the LSEC seen in old age can be exacerbated by diabetes mellitus and prevented or ameliorated by caloric restriction commencing early in life