La terre crue est un des matériaux les plus utilisés au monde pour bâtir. Chaque terre est un mélange de grains de différentes tailles (cailloux, graviers, sables, silts et argiles) en proportions variées. Les particules les plus fines, qui constituent le liant du matériau, se différencient des autres grains par leur petite taille, à laquelle est associée des propriétés colloïdales lorsqu'elles sont mélangées à l'eau. L'argile, au sens granulométrique (particules inférieures à deux microns), contient généralement un mélange d'argiles, au sens minéralogique (phyllosilicates hydratés), d'oxydes de fer, d'aluminium et de silicium. Pour comprendre ce matériau de construction, la terre est envisagée dans un premier temps comme une matière en grains. La physique des milieux granulaires secs et la physique des milieux granulaires humides sont explorées afin de décrire les comportements physiques de cette matière. Des techniques de construction innovantes, qui découlent de cette compréhension, sont présentées. Dans un deuxième temps, l'argile est envisagée comme une matière colloïdale. Comme beaucoup de systèmes naturels, le liant argileux est un mélange de particules aux propriétés de surface différentes, contenant à la fois des charges permanentes négatives et des charges variables avec le pH et la force ionique. Ces systèmes mixtes sont dits hétérocoagulés. Des pistes de recherche, qui découlent de cette compréhension, sont présentées.

Produced water is one of the major by products of oil and gas exploitation which is produced in large amounts up to 80% of the waste stream. Oil and grease concentration in produced water is the key parameter that is used for compliance monitoring, because it is easy to measure. For Canadian offshore operations, the current standard is a 30-day volume weighted average oil-in-water concentration in discharged produced water not exceeding 30 mg/L. Treatment of produced water may therefore be required in order to meet pre-disposal regulatory limits. The measurement of oil in produced water is important for both process control and reporting to regulatory authorities. Without the specification of a method, reported concentrations of oil in produced water can mean little, as there are many techniques and methods available for making this measurement, but not all are suitable in a specific application. The first part of this study focused on selecting a suitable analytical method for oil and grease measurement in oil field produced water. Petroleum ether was found to offer a comparative dissolution of crude oil as dichloromethane and hexane; it was therefore used as the solvent of choice for the UV-Vis spectrophotometric analysis of oil and grease in synthetic produced water. Results from the UV-Vis spectrophotometric and FTIR spectrometric analytical methods were found to be comparable; it confirmed that UV-Vis spectrometry could potentially serve as an alternative method for measuring oil and grease in oil field produced water. However, while the UV-Vis method may have limitations in measuring oil and grease concentrations below 30 mg/L, the FT-IR method was found to be equally efficient at measuring both high and low oil and grease concentrations. Dissolved air flotation (DAF) was the primary treatment technology investigated in this study for removing oil and grease from synthetic produced water. By itself, DAF achieved less than 70% oil and grease (OG) removal, and was not able to achieve a clarified effluent OG concentration of 30 mg/L required for regulatory discharge limits. At an optimum condition of 20 mg/L ferric chloride (FeCl3) at pH 8 (70.6% OG removal), coagulation was found to significantly improve the performance of the DAF unit (p < 0.05). At the optimum conditions of 100 mg/L PAC dose, pH 8 and a mixing time of 10 minutes (77.5% OG removal) and 300 mg/L OC dose, pH 8 and a mixing time of 10 minutes (78.1% OG removal), adsorption was also found to significantly improve the performance of the DAF unit (p < 0.05 in both cases). Adsorption with organoclay was recommended as the best pre-treatment for optimizing the performance of DAF in removing oil and grease from offshore oil field produced water. The bench-scale experiments showed that turbidity removal results were consistent with the OG removal results. Without pre-treatment, DAF achieved significant removal of benzene from produced water due to the volatile nature of benzene. Therefore comparable levels of benzene removal was observed by the DAF, FeCl3/DAF, PAC/DAF and OC/DAF treatment schemes; 79.3 %, 86.6 %, 86.5 %, 83.5% respectively. Finally, as benzene is known to be carcinogenic to humans, this study recommends the incorporation auxiliary equipment in its design, for the treatment of the off-gas (VOCs, particularly BTEX) released during the removal of dissolved oil from the oil field produced water.

Natural organic matter (NOM) is present in all surface waters as a result of decaying vegetation, biological activity, and organic soil. Alternative NOM removal processes such as anion exchange resins (AERs) have shown NOM removals typically ranging between 50 to 90%, with up to 99% removal achieved in some cases. The first portion of this study evaluated the performance of two AERs; a conventional Type 1 AER and magnetic ion exchange resin (i.e. MIEX®) for NOM removal from surface water quantified by UV254, dissolved organic carbon (DOC), and specific UV absorbance (SUVA). Samples were also characterized for chloride, sulphate, and chloride-to-sulphate mass ratio (CSMR) to provide additional information on water quality characteristics of AER treated waters. Overall, the results showed that both AERS were effective for removing NOM. However, the MIEX® resin provided greater removal of NOM with shorter contact times compared to the conventional resin investigated. Water treated with MIEX® resin showed significantly higher chloride and lower sulphate concentrations than the conventional AER. Higher CSMR values were found with MIEX® treated water compared to conventional AER system, although both resins showed CSMR much greater than 0.5, which can increase galvanic corrosion effects with lead. Bench-scale jar tests were conducted to investigate the impact of temperature on the efficacy of three NOM removal treatment technologies; enhanced coagulation with alum, MIEX® and a combined MIEX® treatment followed by coagulation with a low dose of alum. Higher settled water turbidity was observed during cold water operating conditions for all three processes. At cold-water operating conditions, DOC removal was reduced with combined MIEX® -Alum treatment, and UV254 removal was impacted for both MIEX® and MIEX® -Alum processes. The combined MIEX®-Alum process was found to provide the lowest THMFP and HAAFP at both temperatures to concentrations lower than current regulatory maximum acceptable concentration (MAC) guidelines in Canada. Surface charge analysis experiments were performed at bench-scale using synthetic water containing humic acid to determine the relationship between NOM and the charge of AER-treated waters. Further bench and pilot-scale studies were performed to investigate the use of surface charge measurements to monitor and optimize NOM removal during treatment with AER systems. Strong correlations were observed between UV254 and respective charge measurements (i.e. ZP, SC) of AER-treated synthetic and raw waters. The results of this research has shown that it is possible to use charge to optimize the MIEX® process for NOM removal. Additionally, it was found that SC measurements could be used as an operational tool for AER processes, where deviations in SC from optimum treatment would indicate the requirement for fresh resin addition or resin regeneration.

No description available.

This thesis have explored the functions of the protein Tissue Factor (TF), which together with its ligand coagulation factor VII/VIIa (FVII/FVIIa) forms a proteolytic complex that functions in initiation of blood coagulation and activation of cell signaling. In paper I, the mechanisms behind the observation that TF/FVIIa signaling protects cells from apoptosis were further investigated. Using cell culture models, we found that antiapoptotic signaling by TF/FVIIa requires signaling by the Insulin-like growth factor I receptor (IGF-1R), as synthetic IGF-1R inhibitors and IGF1-R siRNA knock-down abolished the antiapoptotic effect of FVIIa. Furthermore, the IGF-1R translocated to the cell nucleus after FVIIa stimulation, implying a role in regulation of gene expression. Papers II and III describe the discovery that the Eph tyrosine kinase receptors EphB2 and EphA2 are proteolytically cleaved directly by TF/FVIIa. By using mass spectrometry and N-terminal Edman sequencing, the exact cleavage site was identified after a conserved arginine residue in the EphA2/EphB2 ligand binding domains, in agreement with the cleavage preferences of FVIIa. TF and EphA2/EphB2 co-localized in cancer cell lines and FVIIa potentiated ligand-dependent Eph signaling by increasing cytoskeletal remodeling and cell repulsion, demonstrating a novel proteolytical event that modulates Eph receptor signaling. In paper IV, expression of TF was investigated in colorectal cancer in both the stromal and tumor cell compartments by immunohistochemistry using an anti-TF-antibody developed and validated by the Human Protein Atlas project. In normal large intestine, TF was strongly expressed in the innermost pericryptal sheath cell layer lining the epithelium, in a cell population distinct from intestinal pericryptal myofibroblasts. We evaluated TF expression in two colorectal cancer materials, and found that TF was variably present in both the stromal and tumor cell compartments. TF expressed by pericryptal sheath cells was progressively lost after the adenoma-to-carcinoma transition and was a strong predictor of survival in rectal but not colon cancer patients independently of disease stage, histological tumor grade and age. In summary, this thesis demonstrates novel signaling mechanisms for the TF/FVIIa complex, and provides evidence of a hitherto unknown role of TF expressed by a specific population of stromal cells in colorectal cancer.

Pulmonary embolism as a part of venous thromboembolic disease has a broad spectrum of clinical presentations from minimal disease to life-threatening right heart failure. Therapy has to be guided by the risk associated with the individual clinical state of the patient. As long as hemodynamics are entirely stable, anticoagulation is given in order to prevent early or late recurrence, thereby allowing for endogeneous thrombolysis and recovery. In hemodynamically instable patients, i.e. patients under cardiopulmonary resuscitation or in shock, there is the need for a rapid reduction of thrombus mass in order to restore right ventricular function. Systemic thrombolysis is the most feasible modality to reduce the thrombus burden of the pulmonary circulation in the short term. For hemodynamically stable patients with right ventricular dysfunction as assessed by echocardiography, there is still some controversy as to whether thrombolysis improves the long-term outcome. At the least, thrombolysis may positively modify the short-term course of acute disease in patients with an extremely low risk of bleeding. When the acute phase has been overcome, secondary prophylaxis with vitamin K antagonists has to be given. The duration of secondary prophylaxis requires an individual assessment of both the risk of recurrence and the risk of bleeding. In the near future, new anticoagulant drugs such as direct thrombin and factor Xa inhibitors will offer new treatment modalities for the acute phase as well as for secondary prophylaxis. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

All artificial organ systems and medical devices that operate in direct contact with blood elicit activation of coagulation and platelets, and their long-term use often necessitates antithrombotic therapies that carry significant cost and bleeding risk. Thrombomodulin (TM) is a major endogenous inhibitor of blood coagulation localized on the endothelial cell surface. The overall objective of this research is to develop clinically durable synthetic materials by incorporating TM as a solid-supported film to actively and sustainably attenuate thrombus formation at the blood-contacting interface. During the course of this research, we developed site-specific approaches to covalently attach TM on the luminal surface of commercial vascular grafts using bioorthogonal chemistry that was compatible with ethylene oxide sterilization. Notably, we demonstrated the superior efficacy of TM to reduce platelet deposition compared with commercial heparin modified grafts using a non-human primate model of acute graft thrombosis. Finally, we optimized a novel reversible chemistry to rapidly and repeatedly regenerate immobilized TM, with the potential to significantly extend the lifetime of biologically active films.

The formation of disinfection by-products (DBPs) in drinking water has become an issue of greater concern in recent years. Bench-scale jar tests were conducted on a surface water to evaluate the impact of enhanced coagulation on the removal of organic DBP precursors and the formation of trihalomethanes (THMs) and haloacetic acids (HAAs). The results of this testing indicate that enhanced coagulation practices can improve treated water quality without increasing coagulant dosage. The data generated were also used to develop artificial neural networks (ANNs) to predict THM and HAA formation. Testing of these models showed high correlations between the actual and predicted data. In addition, an experimental plan was developed to use ANNs for treatment optimization at the Peterborough pilot plant.

The formation of disinfection by-products (DBPs) in drinking water has become an issue of greater concern in recent years. Bench-scale jar tests were conducted on a surface water to evaluate the impact of enhanced coagulation on the removal of organic DBP precursors and the formation of trihalomethanes (THMs) and haloacetic acids (HAAs). The results of this testing indicate that enhanced coagulation practices can improve treated water quality without increasing coagulant dosage. The data generated were also used to develop artificial neural networks (ANNs) to predict THM and HAA formation. Testing of these models showed high correlations between the actual and predicted data. In addition, an experimental plan was developed to use ANNs for treatment optimization at the Peterborough pilot plant.

The physiological role of the plasma contact system still remains a partial enigma. The aim of the presented work was to expand our understanding of the plasma contact system, focusing on its physiological activation and function, principally from a hemostatic perspective. It also explored contact system activation under pathological conditions. We found that when human platelets become activated in blood, plasma proteins of the contact system bind to platelets and initiate contact activation. The platelet-triggered contact activation contributed to clot formation by shortening the clotting time and enhancing clot stability. We demonstrated that the regulation of contact activation elicited by activated platelets differed from the previously described contact activation elicited by negatively charged material surfaces. Platelet-triggered contact activation and activation propelled by clotting blood were found to be regulated by antithrombin, whereas material-induced activation was regulated by C1 inhibitor. We also showed that the fibrin fibers that are formed during the clot process further enhance and propagate the contact activation initially induced by activated platelets. Fibrin not only activated factor XII but also seemed to increase the affinity of antithrombin for the proteases of the contact system, leading to the generation of contact enzyme-antithrombin complexes during clot formation. To determine whether the contact system might be involved in the inflammation and vascular disease associated with systemic lupus erythematosus (SLE), we analyzed plasma samples from SLE patients. These patients were found to have altered levels of contact enzyme-serpin complexes, supporting the concept that the contact system may be involved in the pathophysiology of SLE. The contact enzyme-antithrombin complexes were clearly linked to platelet activation in vivo. Altered levels of both FXIIa-antithrombin and FXIIa-C1 inhibitor were found to be correlated with previous vascular disease and may therefore be potential biomarkers for assessing the risk of thrombotic events in SLE patients. These findings add to our knowledge of how the plasma contact system is activated and functions in vivo and will help us to understand the role of the contact system, not only in hemostasis but also in vascular disease and thrombotic conditions.