FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Third molar surgery is a frequent procedure in dentistry related to variable degrees of postoperative pain. In this context, non-steroidal anti-inflammatory drugs have been commonly used in studies that evaluated the efficacy of preemptive analgesia as a strategy for pain control. Thus, the aim of the present study was to evaluate the preemptive analgesic efficacy and anti-inflammatory effect of ibuprofen and etoricoxib in mandibular third molar surgery, compared with a placebo. A randomized, double-blind, placebo-controlled crossover trial was conducted with patients undergoing a surgical removal of mandibular third molars with similar pattern of bone inclusion and surgical difficult between right and left sides, requiring bone removal under local anesthesia. Eighteen eligible patients were allocated into three groups to receive 1 hour preoperatively a single dose of ibuprofen 400 mg, etoricoxib 120 mg, or placebo. Pain intensity, use of analgesic rescue medication, swelling and maximum mouth opening were evaluated. The overall median (minimum - maximum) of pain scores was different between groups (p < 0.0001): ibuprofen, 0.0 (0.0 â 5.5); etoricoxib, 0.0 (0.0 â 3.5); placebo, 1.0 (0.0 â 7.0). Etoricoxib reduced pain scores significantly in comparison with ibuprofen (p < 0.05). The pain score peak occurred 6 hours after surgery between 3 compared groups (p < 0.0001). Rescue medication was used in 83.33%, 75%, and 100% of surgical procedures receiving ibuprofen, etoricoxib, and placebo, respectively (p = 0.1967). The mean of consumed rescue medication was different between ibuprofen (1.7Â2.0), etoricoxib (0.8Â06), and placebo (1.0Â2.7) groups over the study period (p = 0.0052), and was significantly lower in etoricoxib group by comparison with the placebo group (p < 0.05). Among study periods, there was no statistically significant difference between groups in relation to median values of facial swelling (p > 0.05) and mean values of maximum mouth opening (p > 0.05). In conclusion, ibuprofen and etoricoxib significantly reduced the intensity of postoperative pain and the need for use of rescue medication compared to placebo group. Etoricoxib showed a better preemptive analgesic activity than ibuprofen. Both drugs did not exert significant anti-inflammatory effect able to reduce swelling and trismus in comparison with placebo group. / A cirurgia de terceiros molares à um procedimento frequente em Odontologia relacionado a variados graus de dor pÃs-operatÃria. Nesse contexto, drogas anti-inflamatÃrias nÃo-estereoidais tÃm sido comumente utilizadas em estudos que avaliaram a eficÃcia da analgesia preemptiva como uma estratÃgia para controle da dor. Portanto, o objetivo do presente estudo foi avaliar a eficÃcia da analgesia preemptiva e aÃÃo anti-inflamatÃria do ibuprofeno e etoricoxibe em cirurgia de terceiros molares mandibulares comparado a um placebo. Foi realizado um ensaio clÃnico randomizado, duplo-cego, placebo-controlado cruzado com pacientes submetidos a cirurgia para remoÃÃo de terceiros molares mandibulares, com padrÃes similares de inclusÃo Ãssea e dificuldade cirÃrgica entre os lados direito e esquerdo, e que requeriam remoÃÃo Ãssea sob anestesia local. Dezoito pacientes elegÃveis foram randomicamente alocados em trÃs grupos para receber 1 hora preoperatoriamente dose Ãnica de ibuprofeno 400mg, etoricoxibe 120mg, ou placebo. Intensidade de dor, uso de medicaÃÃo analgÃsica de resgate, edema e mÃxima abertura bucal foram avaliados. A mediana (mÃnimo - mÃximo) global dos escores de dor diferiu entre os grupos (p < 0,0001): ibuprofeno, 0,0 (0,0 â 5,5); etoricoxibe, 0,0 (0,0 â 3,5); placebo, 1,0 (0,0 â 7,0). Etoricoxibe reduziu os escores de dor significantemente em comparaÃÃo ao ibuprofeno (p < 0,05). O pico de dor ocorreu 6 horas apÃs a cirurgia entre os 3 grupos comparados (p < 0,0001). MedicaÃÃo de resgate foi utilizada em 83,33%, 75% e 100% dos procedimentos cirÃrgicos que receberam ibuprofeno, etoricoxibe e placebo, respectivamente (p = 0,1967). A mÃdia de medicaÃÃo de resgate consumida diferiu entre os grupos ibuprofeno (1,7Â2,0) e etoricoxibe (0,8Â0,6) e placebo (1,0Â2,7) durante todo o perÃodo de estudo (p = 0,0052), e foi significantemente menor no grupo do etoricoxibe em comparaÃÃo com o grupo placebo (p < 0,05). Entre os perÃodos de avaliaÃÃo do estudo, nÃo existiu diferenÃa estatisticamente significante dos grupos entre si em relaÃÃo à mediana dos valores de edema facial (p > 0,05) e à mÃdia dos valores de mÃxima abertura bucal (p > 0,05). Em conclusÃo, ibuprofeno e etoricoxibe reduziram significantemente a intensidade de dor pÃs-operatÃria e a necessidade do uso de medicaÃÃo de resgate comparado ao grupo placebo. Etoricoxibe mostrou melhor atividade analgÃsica preemptiva do que o ibuprofeno. Ambas as drogas nÃo exerceram efeito anti-inflamatÃrio significante capaz de reduzir edema e trismo em comparaÃÃo ao grupo placebo.

Recently a large amount of interest has developed around separating out impurities of small size; pertinent examples are found within fuel and solvent processing. For such applications a leading candidate process is nanofiltration. This thesis focuses on SRNF (solvent resistant nanofiltration) composite membranes consisting of a dense polymer active layer bonded to a stronger, but ultimately more porous, support layer. The composite membranes that have been produced during the course of this work consist of a PDMS (polymdimethylsiloxane) active layer bonded to a commercially available support layer of PAN (polyacrylonitrile). To create the membrane a monomer was spread over the support layer and then polymerised to form the matrix which was responsible for separation. Commercially, either heat or radiation is often applied to cause polymerisation, however the membranes in the current work have been formed by the used of a homogeneous catalyst. This thesis investigates the transport and separation dynamics of the produced membranes for a series of fuel simulants composed of organometallics and poly-nuclear aromatic solutes dissolved in aromatic and alkane solvents. Membrane composition and the extent of polymer swelling were found to be the two key factors which had the greatest influence on solvent flux and solute rejection. By increasing catalyst concentration it was found that the dual effects of increased rejection and reduced flux occurred, with the converse also being true. The effective pore size of the membrane could also be controlled by varying the catalyst amount during manufacture as this directly affected the limit of crosslinking which formed. Polymer swelling was the most pronounced using solvents with a solubility parameter close to that of the polymer. The membrane transport mechanism was most accurately forecast by the solution diffusion model for flux predictions and the convection diffusion model for rejection predictions, however all the models tried were in close agreement. This was postulated to be due to the swelled polymer matrix which allows for both convective and diffusive transport to occur.

Abstract This thesis presents an effective optical method for measuring liquid sorption into paper. From the two tested methods, based on a streak-camera and optical coherence tomography (OCT), the last-mentioned proved very promising for investigating dynamical paper-liquid interactions as spatially and temporally dependent processes. The streak-camera measurements were performed to explore the relationship between paper properties and light migration in dry and refractive index matched paper in general. Based on streak-camera measurements, a novel procedure for determining the average refractive index of cellulose fibre tissue was also presented here. In addition, the streak camera method lent itself to paper porosity determination. Results of the performed OCT measurements proved that liquids cannot penetrate into paper before filling the pores and pits of the paper surface. As a liquid penetrated into paper, the border between the wetted and dry area could be investigated in the depth direction. The liquid penetration velocity seemed to be slower at the beginning and end of the process. Liquid absorption into paper fibres could be investigated concurrently. For the first time, the location and moment of structural changes in paper could be determined during wetting, and the effect of three different coexistent subprocesses related to paper wetting could be detected. OCT only fell short of detecting the effect of liquid migration along fibres. Despite the limitations of the utilized method (resolution, probing depth and depth scanning rate), the obtained OCT measurement results are very promising for the development of an effective paper wetting measurement device for industrial applications. Even if this thesis focused on paper wetting, it is reasonable to assert that the presented ideas and obtained results have more general value in terms of explaining liquid penetration into porous structures and offer an alternative method of evaluating that process.

The bonding of fibres in paper is influenced by environmental changes (e.g. moisture) that may cause unstable fibres to move. These movements include cell-wall swelling, fibre lifting and/or puffing that break inter-fibre bonds and lead to reduced strength and surface roughness. Fibre puffing is defined as the expansion of the lumen area as result of changes in the environment. Puffing was investigated through image analysis of scanning electron micrographs. Detailed images were obtained with samples that were embedded in resin and then etched. Puffing of fibres was then quantified by calculating the ratio of lumen area to fibre area. Stability of softwood and hardwood fibres was studied in this way, and to simulate printing, handsheets were calendered and rewetted. This method was later validated against commercial sheets. Compared to softwood, hardwood fibres were more stable and most of the handsheet properties were retained after rewetting. Mannanase and/or endoglucanase treatments resulted in improved fibre stability by increasing fibre bonding, fibrillation or fibre collapse. Mannanase improved handsheet smoothness and strength as well as fibre stability, but endoglucanase was less effective. The effect of the enzymes was more difficult to observe on hardwood fibres, because even untreated fibres were more stable under moist conditions. Thin-walled fibres such as earlywood were less stable than latewood fibres, but it responded better to mannanase treatment. Thick-walled fibres (latewood), on the other hand, were more difficult to improve with enzymes. The potential of enzymes to improve fibre stability of commercial pulp was tested on chemi-thermo-mechanical pulp (CTMP) and bleached CTMP. Enzyme treatment improved fibrillation and reduced beating energy of bleached CTMP. Mannanase again resulted in the most improved fibre stability. On rejects, a lack of response to enzymes was overcome by pre-treating the pulp with alkaline peroxide. This study provided new insights into the stability of fibres with different morphology. It was also demonstrated that fibre stability can be improved with enzyme treatment and it is expected that this knowledge could have significant commercial value. / Dissertation (PhD)--University of Pretoria, 2010. / Microbiology and Plant Pathology / unrestricted

This diploma thesis is aimed at verifying the properties of joints of waterproofing membranes generaly used in underground constructions and also deals with the possible addition of a swelling profile as a barrier to permeating water through the defect in the waterproofing system. The most commonly used materials for waterproofing membranes are polymers. The work is focused on verifying the properties of automatic and manual welding joints of polyvinylchloride membrane. In actual practice, there is a pressure test being used for automatic weldings, and for manual weldings there are tests with a tear-off needle and a vacuum bell. In the laboratory, it is also possible to verify the joints using a peeling test and determining the shear strength of the joint using a testing device. In case of damaged waterproofing system and soaking of pressurized water, it is possible to use a swellable strip as a barrier for the water leaking from one injection compartment to another. At the end of the thesis there is a comparison of the waterproofing system without the swelling profile and the system including its application. The swelling profile has shown very good properties with regard to the infiltration of the flowing water into its structure, and so the amount of water that could be applied to the sample with the swelling profile was much higher than in the case of the generaly used waterproofing system.

The new forms of superabsorbent polymers (SAP) on the base of acrylic acid were developed and studied in this thesis. The SAP are focused on agricultural and environmental applications. While they are applied to the soil, SAP can prevent water losing and they become a reservoir of humidity in case of dry season, moreover in combination with fertiliser they play role of controlled release medium. Eight various samples of SAP were experimentally prepared by networking of partially neutralized acrylic acid. Potassium peroxydisulfate was used as the initiator and N,N–methylenebisacrylamide as the crossing agent. Some of samples contained addition of second monomer of acrylamide. All of them were enriched by fertilisers – natural lignohumate or synthetic NPK or combination of both. The swelling characteristics of prepared samples were investigated in conditions of various ionic strength. The influence of xerogels’ particles size on swelling properties was also observed. The viscoelastic characteristics of hydrogel form of all SAP were determined by using of rotation rheometer. The changing of viscoelastic properties were studied in dependence on time, on freezing and on repeating swelling cycles. On top of that the controlled releasing ability of SAP was tested due to three modelling experiments. The biological activity of all polymer products was tested at the end of the thesis. All samples of SAP were incorporated into the artificial soil and the ability of the water retention in the soil was observed. The growing experiments were running by using of corn plants. The size and the mass of each plant were measured and branching of the root was objectively evaluated by programme Harmonic and Fractal Image Analyzer.

This work provides an insight into how the molecular interactions influence macroscale properties of two materials: swelling clay and oil shale. Swelling clays cause enormous damage to infrastructure: buildings, roads, and bridges. Understanding the mechanisms are essential to prevent the detrimental effects and use of these clays for engineering applications. Our group studied the effect of fluid polarity on sodium montmorillonite (Na-MMT) swelling clay mineral using molecular modeling and experiments for bridging the molecular level behavior with the microstructure, swelling pressure, permeability, and compressibility. Various polar fluids (Dielectric Constant 110 to 20) found in landfill leachates are used. Our molecular dynamics (MD) simulations show that the nonbonded interactions of Na-MMT with polar fluids are higher than with low and medium polar fluids. These results are consistent with the results from Fourier transform infrared (FTIR) spectroscopy experiments. The polarity of the fluids and the fluid content influence the interlayer spacing, interlayer modulus, nonbonded interactions, and conformation as well as the shear strength parameters, the angle of internal friction (φ) and cohesion (c). Furthermore, the unconfined compressive strength experiments are used to evaluate the undrained cohesion at various swelling level. The nanomechanical properties, the modulus of elasticity (E) and hardness (H), of the undisturbed dry and saturated Na-MMT at various level of swelling are evaluated using nanoindentation experiments for the first time. The undrained cohesion, modulus of elasticity, and hardness decrease with increase in swelling level. Swelling controls the microstructure of Na-MMT clay, and the clay particles breakdown into smaller sizes with increase in swelling level. The Green River Formation located in the United States is the richest oil shale deposit in the world. Oil shale contains clay minerals, bitumen, and kerogen—a precursor to crude oil. A three-dimensional (3D) kerogen model is built from seven fragments, and the interactions of kerogen with Na-MMT is investigated using MD simulations to understand how the kerogen is bound to the clay mineral. The nonbonded interactions between Na-MMT and kerogen as well as among kerogen fragments are found. This work seeks to develop new methods to extract kerogen economically and efficiently. / Department of Energy (DoE) / Mountain Plains Consortium (MPC) / North Dakota Established Program to Stimulate Competitive Research (ND EPSCoR)

This diploma thesis is focused on development and characterization of synthetic hydrogel materials containing humic acids. Based on the literature review, procedure for the preparation of synthetic superabsorbent containing humic acids was designed and optimized in order to maintain required functionality of the resulting materials, such as swelling abilities and to the controlled the release of humic substances. Very important part of this work was also characterization of superabsorbents by wide range of routine physic-chemical methods (rheometry, moisture analyzers, FT-IR). Preparation of these materials is aimed to their use in agriculture and in the environment.

Ce travail a pour objectif d’étudier la fissuration des sols due au séchage par des approches numérique et analytique. L’initiation et la propagation des fissures sont investiguées en utilisant un code de calcul aux éléments finis avec la présence des joints cohésifs. Les couplages entre le problème hydraulique et le comportement mécanique en présence des discontinuités sont considérés. La loi de la fissure cohésive est appliquée pour modéliser l’initiation et la propagation des fissures.Tout d’abord, les résultats d’un essai de séchage au laboratoire réalisé sur un sol argileux à l’état liquide sont utilisés afin d’évaluer la méthode numérique proposée. Les résultats numériques montrent que le modèle est capable de reproduire les tendances principales du processus de séchage. Elle souligne aussi l’importance des conditions aux limites dans l’initiation des fissures. Ensuite, une approche énergétique est proposée pour étudier l’initiation d’une fissure. Les énergies élastiques avant et après l’initiation de la fissure sont estimées par les deux approches analytique et numérique. L’énergie dissipée lors de l’initiation de la fissure est comparée avec le taux d’énergie pour créer une fissure. Les analyses montrent que le critère d’énergie peut est atteint avant le critère de contrainte. La dissipation de l’énergie cumulée correspond à la propagation instable lors de l’initiation de la fissure. De plus, le développement et la géométrie des fissures sont étudiés essentiellement par les simulations numériques avec plusieurs joints cohésifs. Les résultats numériques montrent que la fissuration se produit souvent progressivement pour former différentes familles de fissures par un processus dichotomique (une fissure apparait au milieu de deux fissures existantes). La propagation d’une fissure est brutale dans la phase d’initiation pour atteindre une profondeur appelée ‘ultime’. Les fissures dans chaque famille peuvent apparaitre simultanément à un même niveau de succion et présentent une même profondeur ultime. En se basant sur les résultats numériques et quelques analyses analytiques supplémentaires, des relations empiriques sont proposées afin de prédire l’espacement et la profondeur ultime des fissures. Finalement, quelques calculs préliminaires sont réalisés afin d’évaluer le potentiel de la méthode numérique proposée pour prédire la fissuration liée au séchage des ouvrages en terre / This work focuses on the analysis of desiccation cracking by numerical and analytical approaches. The initiation and the propagation of cracks are investigated by using a finite element code including cohesive joints elements. Coupling between the hydraulic and the mechanical processes in the presence of discontinuities is considered. The cohesive crack’s law is applied to simulate the initiation and the propagation of cracks.Results of a laboratory experiments performed on slurry clay soil are first used to evaluate the proposed numerical modelling method. The results show that the method is able to reproduce the main trends of desiccation process. The importance of boundary conditions are also discussed. Second, an energy approach is proposed to study the initiation of cracks. The energies before and after crack initiation are estimated by both numerical and analytical solutions. The energy released by cracking is then compared to the crack energy to discuss crack initiation conditions. The analysis shows that the energy criterion is reached before the stress criterion, and this can explain unstable crack propagation at the beginning. Third, the development and the geometry of desiccation cracks are studied by numerical simulation with several cohesive joints. The numerical results show that cracking occurs sequentially to form different cracks families with a dichotomy process (the subsequent cracks appear at the middle of two existing neighboring ones). The cracks in each family appear simultaneously and reach an identical ultimate depth. From the numerical results and additional analytical analysis, empirical correlations are proposed to predict the spacing and crack depth. Finally, some preliminary studies are performed showing that the proposed numerical method can be used to predict the desiccation crack phenomena observed on geotechnical earth structures

Risk of death from cardiovascular disease is substantially increased throughout winter season and by exposure of organism to acute cold stress. However, several studies have suggested that some cold acclimation models could act cardioprotectively. The thesis is focused on effects of acute and chronic cold acclimation on swelling of rat heart mitochondria. Mitochondrial swelling is, besides other things, caused by massive influx of Ca2+ into the mitochondria especially during ischemia-reperfusion injury. By that, mitochondria permeability transition pore is being opened and subsequently, this could end up in mitochondrial burst and cell death, eventually. Lower rate of mitochondrial swelling indicates greater mitochondrial resistance. The results express higher mitochondrial resistance after acute cold exposure and chronic cold acclimation. Key words: cold, mitochondria, Ca2+ ions, swelling, MPTP, myocardium, ROS, ischemia