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archives@tulane.edu / 1 / Genevieve Mattei

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Introduction Liver resection offers curative treatment to a number of malignant conditions. It has traditionally been associated with poor post-operative outcomes. More recently a mortality rate of less than five per cent has become established but morbidity remains high. Enhanced Recovery After Surgery (ERAS) has become established practice in a number of surgical specialties and has shown improvement in post-operative outcomes. ERAS has been introduced for liver resection however practice is less well established and liver surgery has several complexities that need to be accommodated in order to optimise post-operative care. The following thesis aims to identify areas that require clarification and investigate peri-operative care components to establish optimum practice. Methods Systematic review and meta-analysis were performed to identify areas that required clarification and were lacking in sufficient evidence to guide practice. A randomised controlled trial was performed to compare established areas of practice. Prospective observational studies were performed when exploratory investigation was required. Retrospective analysis of a prospectively collected database was performed to identify risk factors for post-operative morbidity. Patients included in the above trials underwent liver resection at the Royal Infirmary of Edinburgh, UK, between December 2012 and August 2014. Results Post-operative analgesia after liver resection was identified as being an area that was controversial. Continuous wound infiltration was shown to offer improved recovery times when compared to epidural with no significant associated disadvantages. After retrospective review of 603 liver resections, extended resection was observed to be associated with high morbidity rates. It was hypothesised that post-operative nutritional requirements might be higher in these patients. This was not found to be the case but post-operative energy requirements were found to be difficult to predict after liver resection, suggesting the benefits of real-time monitoring of energy expenditure. Finally acetaminophen metabolism was suspected of being altered after major resection. An observational study suggested that despite altered metabolism, glutathione deficiency was not observed after major resection and so liver volume was not a contra-indication to acetaminophen administration. Summary Liver resection offers a complex set of conditions on which to base an enhanced recovery protocol. Current ERAS literature does not completely address these issues. This thesis has investigated several aspects of care unique to liver surgery in an attempt to optimise peri-operative care and improve post-operative outcome after liver surgery.

This dissertation details the effect of underpotentially deposited (UPD) Pb on the surface enhanced Raman scattering (SERS) ability of roughened polycrystalline Ag electrodes. The deposition of monolayer and submonolayer amounts of Pb results in a quenching of the SERS response for pyridine and Cl⁻ adsorbed at Ag electrodes. Various factors which may contribute to the loss of SERS intensity are investigated. The most significant factors include changes in surface roughness features brought about by Pb UPD, changes in surface electronic properties of Pb-modified Ag and changes in a chemical contribution to surface enhancement. Possible changes in surface roughness properties of the Ag electrode due to Pb deposition are examined using scanning electron microscopy (SEM) and SERS reversibility studies. SEMs of roughened Ag electrodes before and after Pb monolayer deposition show no significant change in the morphology of the larger roughness features. However, the deposition and stripping of 60 - 70% of a Pb monolayer results in a loss of ca. 50% of the original SERS intensity for both adsorbate bands. This irreversible loss of SERS intensity is attributed to the destruction of atomic scale roughness (ASR). These results suggest that ca. 50% of the observed SERS response arises from a mechanism involving ASR. In addition, the destruction of ASR is shown to be largely responsible for the quenching of SERS at higher Pb coverages. The morphology of the SERS quenching profiles at lower Pb coverages for pyridine and Cl⁻ varies as a function of excitation wavelength. Experimental quenching profiles are compared with theoretical quenching profiles based on an electromagnetic contribution to SERS. Theoretical quenching profiles are calculated using a model for electromagnetic enhancement at a overlayer-covered ellipsoids proposed by Murray. The experimental results for both adsorbates are in agreement with the theoretical predictions for laser excitation in the blue. Experimental results in the green and red wavelength regions are best explained in terms of photoassisted charge-transfer mechanisms for surface enhancement.

A study of pool boiling of a dielectric liquid (PF 5060) from single-layered enhanced structures was conducted. The parameters investigated were the heat flux, the width of the microchannels and the microchannel pitch. The boiling performance of the enhanced structures increases with increase in channel width and decrease in channel pitch. Simple single line curve fits are provided as a practical way of predicting the data over the entire nucleate boiling regime. The influence of confinement on the thermal performance of the enhanced structures was also assessed. The main parameter investigated was the top space (0 mm { 13 mm). High-speed visualization was used as a tool . For the total confinement ( = 0 mm), the heat transfer performance of the enhanced structures was found to depend weakly on the channel width. For >0 mm, the enhancement observed for plain surfaces in the low heat fluxes regime is not present for the present enhanced structure. The maximum heat flux for a prescribed 85 oC surface temperature limit increased with the increase of the top spacing, similar to the plain surfaces case. Two characteristic regimes of pool boiling have been identified and described: isolated flattened bubbles regime and coalesced bubbles regime. A semi-analytical predictive model applicable to pool boiling under confinement is developed. The model requires a limited number of empirical constants and is capable of predicting the experimental heat flux within 30%.

All projects employ work packaging to divide the project scope into manageable portions of work for planning and execution. Enhanced work packaging, however, provides an organized and structured approach to planning through the project lifecycle in order to provide the construction work face with everything they need to successfully execute their work. This approach leads to increased field productivity and project predictability in terms of cost and schedule. Construction Industry Institute (CII) Research Team (RT) 272 developed a lifecycle execution model that encompasses recommendations for implementing enhanced work packaging throughout the project lifecycle. The model provides work packaging steps and considerations for each project phase from project definition through construction to system turnover. The model was founded upon industry practices as recorded in literature, team experiences, and through case studies and expert interviews. These recommendations were validated in conjunction with the case studies and through expert review. When properly implemented, enhanced work packaging improves field productivity, cost and schedule predictability, safety performance, and reduced rework, amongst other benefits. / text

Due to capillary pressure, reservoir heterogeneity, oil mobility, and lack of reservoir energy, typically more than 50 % of the original oil in place is left in the reservoir after primary and secondary recovery oil production. With relatively easy-to-get conventional oil resources diminishing and the price of oil hovering around triple digits, enhanced oil recovery methods, such as polymer flooding, have become very attractive ways to recover oil effectively from existing reservoirs. Enhanced oil recovery methods can be categorized into three categories: water or chemical based, gas based, and thermal based. This thesis will focus on the chemical injection of surfactants, alkali, and polymer of the water based methods. Surfactants are used to alter the interfacial tension of the aqueous and oleic phases in order to facility oil production. Alkali chemicals are used to create surfactants by reacting with acidic oil. And polymer is used to reduce injection water mobility to effectively displace the contacted oil in heterogeneous reservoirs by improving the volumetric and displacement sweep efficiencies. This research presents several laboratory results of polymer and alkali/surfactant/polymer core floods performed in the Center for Petroleum and Geosystems Engineering laboratories. Properties of polymer and surfactant phase behavior were measured and modeled and each coreflood was history matched with UTCHEM, a three-dimensional chemical flooding simulator. The coreflood results and the history matched model parameters were then upscaled to a pilot case for viscous oil in offshore environment with four wells in a line drive pattern. The potential of polymer flooding was investigated and several sensitivity cases were performed to evaluate the effect of various physical property parameters on oil recovery. Water salinity and hardness (i.e. amount of calcium and magnesium) has detrimental effects on polymer viscosity and its stability. The potential benefits of low salinity water injection by desalinization of seawater for polymer flood projects have been discussed in recent publications. The effect of low salinity polymer flood was also investigated. A series of sensitivity studies on well pattern and well spacing is carried out to investigate the impact on recovery factor and recovery time. / text

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