Pacientes com comprometimento pleural por neoplasias malignas freqüentemente apresentam derrame pleural recidivante. Nestes casos, a sínfise das membranas pleurais (pleurodese) com a finalidade de evitar o acúmulo de líquido no espaço pleural deve ser considerada. O talco é o agente mais utilizado indicado para essa finalidade. Entretanto, seu uso terapêutico continua controverso devido aos efeitos deletérios que podem advir de sua utilização. O mais grave entre todos é a insuficiência respiratória aguda, que pode evoluir para a síndrome do desconforto respiratório agudo (SDRA). Essa complicação pode estar relacionada com a composição, com o tamanho das partículas de talco e com a resposta inflamatória desencadeada pelas mesmas. O objetivo deste estudo foi avaliar os efeitos pulmonares e sistêmicos em resposta à injeção intrapleural (IIP) de talco de partículas pequenas (TP) e de partículas de tamanhos diversos (TM). Cem coelhos foram submetidos à IIP com talco. Metade dos animais foi injetada com TP (diâmetro médio= 6,41 mm) e outra metade com TM (diâmetro médio= 21,15 mm), que é o talco usado na prática clínica. Quinze coelhos compuseram o grupo controle. Foram avaliados a celularidade, os níveis de desidrogenase lática (DHL), proteína C reativa (PCR), interleucina-8 (IL-8) e fator de crescimento endotelial vascular (VEGF) no sangue e no lavado broncoalveolar (LBA) às 6, 24, 48, 72 e 96 horas após a IIP. Realizou-se também a quantificação de partículas de talco e a análise histológica dos pulmões. Utilizamos o teste t e Anova na análise estatística, considerando p< 0,05 como significância estatística. A maioria dos parâmetros avaliados apresentou níveis mais elevados no sangue e no LBA dos animais injetados com TP ou TM quando comparados ao grupo controle, sugerindo uma resposta sistêmica e pulmonar à IIP de talco. Com relação aos grupos de talco, os níveis de PCR e de IL-8 apresentaram-se mais elevados no sangue e no LBA dos animais injetados com TP. Partículas de talco foram observadas em todas as lâminas examinadas, sem diferenças significativas entre os grupos. Os pulmões dos animais injetados com TP apresentaram infiltrado linfomononuclear mais exuberante que no grupo TM. A resposta inflamatória pulmonar antecedeu (24 h) a resposta sistêmica (48 h), sugerindo que o pulmão é o principal órgão da resposta sistêmica aguda. Estes achados estudo nos permitem concluir que o talco calibrado com partículas maiores deva ser utilizado na prática clínica, objetivando uma pleurodese mais segura. / Talc has been the pleurodesis agent of choice for the local treatment of recurrent pleural diseases. However, serious concerns exist about its safety. The acute respiratory failure is considered its most serious complication. The physiopathologic mechanisms involved are still unclear. It has been attributed to the systemic dissemination of small talc particles, to the composition of talc and to the inflammatory response. The purpose of this study was to evaluate the systemic and pulmonary response following intrapleural instillation of small particles talc (ST) and mixed particles talc (MT). One hundred rabbits received intrapleural instillation of talc as follows: fifty rabbits were instilled with ST (mean diameter=6,41 microns), and 50 rabbits with MT (mean diameter= 21,15 microns). As control (without talc instillation) were used 15 animals. We studied the pulmonary and systemic inflammatory response (total cell count and differential, levels of lactate dehydrogenase (LD), C-reactive protein (PCR), interleukin-8 (IL-8) and human vascular endothelial growth factor (VEGF) in serum and bronchoalveolar lavage (BAL). Histologic analysis of both lungs and quantitation of talc particles were done at 6, 24, 48, 72 and 96h. ST group showed higher pulmonary and systemic inflammatory response than did the MT group. PCR and IL-8 concentrations were higher in serum and BAL of ST group than the MT group. Many talc particles were observed in the pulmonary tissue of both talc groups, but without statistical significance. We also observed a predominance of cellular infiltrates (lymphomononuclear cells) in the lungs of ST group. The pulmonary inflammatory response (increased IL-8 in BAL) was earlier (24h) than the systemic inflammatory response (48 h). These observations suggest that the main organ in the systemic inflammatory acute response is lung. So, we recommend the clinical use of mixed talc without small particles to induce safety pleurodesis.

Microcalorimetric measurements and contact angle measurements were conducted to study the surface chemistry of powdered minerals. The contact angle measurements were conducted on both flat and powdered talc samples, and the results were used to determine the surface free energy components using Van Oss-Chaudhury-Good (OCG) equation. It was found that the surface hydrophobicity of talc increases with decreasing particle size. At the same time, both the Lifshitz-van der Waals (gSLW) and the Lewis acid-base (gSAB) components (and, hence, the total surface free energy (gS)) decrease with decreasing particle size. The increase in the surface hydrophobicity and the decrease in surface free energy (gS) can be attributed to preferential breakage of the mineral along the basal plane, resulting in the exposure of more basal plane surfaces to the aqueous phase. Heats of immersion measurements were conducted using a flow microcalorimeter on a number of powdered talc samples. The results were then used to calculate the contact angles using a rigorous thermodynamic relation. The measured heat of immersion values in water and calculated contact angles showed that the surface hydrophobicity of talc samples increase with decreasing particle size, which agrees with the direct contact angle measurements. A relationship between advancing water contact angle qa, and the heat of immersion (-DHi) and surface free energies was established. It was found that the value of -DHi decrease as qa increases. The microcalorimetric and direct contact angle measurements showed that acid-base interactions play a crucial role in the interaction between talc and liquid. Using the Van Oss-Chaudhury-Good's surface free energy components model, various talc powders were characterized in terms of their acidic and basic properties. It was found that the magnitude of the Lewis electron donor, gS-, and the Lewis electron acceptor, gS+, components of surface free energy is directly related to the particle size. The gS- of talc surface increased with decreasing particle size, while the gS+ slightly decreased. It was also found that the Lewis electron-donor component on talc surface is much higher than the Lewis electron-acceptor component, suggesting that the basal surface of talc is basic. The heats of adsorption of butanol on various talc samples from n-heptane solution were also determined using a flow microcalorimeter. The heats of adsorption values were used to estimate % hydrophilicity and hydrophobicity and the areal ratios of the various talc samples. In addition, contact angle and heat of butanol adsorption measurements were conducted on a run-of-mine talc sample that has been ground to two different particle size fractions, i.e., d50=12.5 mm and d50=3.0 mm, respectively. The results were used to estimate the surface free energy components at the basal and edge surfaces of talc. It was found that the total surface free energy (gS) at the basal plane surface of talc is much lower than the total surface free energy at the edge surface. The results suggest also that the basal surface of talc is monopolar basic, while the edge surface is monopolar acidic. The results explain why the basicity of talc surface increases with decreasing particle size as shown in the contact angle and microcalorimetric measurements. Furthermore, the effects of the surface free energies of solids during separation from each other by flotation and selective flocculation were studied. In the present work, a kaolin clay sample from east Georgia was used for the beneficiation tests. First, the crude kaolin was subjected to flotation and selective flocculation experiments to remove discoloring impurities (i.e., anatase (TiO2) and iron oxides) and produce high-brightness clay with GE brightness higher than 90%. The results showed that a clay product with +90% brightness could be obtained with recoveries (or yields) higher than 80% using selective flocculation technique. It was also found that a proper control of surface hydrophobicity of anatase is crucially important for a successful flotation and selective flocculation process. Heats of immersion, heats of adsorption and contact angle measurements were conducted on pure anatase surface to determine the changes in the surface free energies as a function of the surfactant dosage (e.g. hydroxamate) used for the surface treatment. The results showed that the magnitude of the contact angle and, hence, the surface free energy and its components on anatase surface varies significantly with the amount of surfactant used for the surface treatment. / Ph. D.

In this thesis, geometry is used as a basis for conducting experiments aimed at growing and arranging inorganic minerals on curved interfaces. Mineralisation is directed using crystalline and liquid-crystalline metallic soaps and surfactant/water systems as templates.¶ A review of the history, syntheses, structure and liquid crystallinity of metallic soaps and other amphiphiles is presented as a foundation to understanding the interfacial architectures in mesostructured template systems in general.¶ In this study, a range of metallic soaps of varying chain length and cation type are synthesised and characterised to find potentially useful templates for mineral growth. These include alkaline-earth, transition metal, heavy metal and lanthanide soaps. These are systematically characterised using a variety of analytical techniques, including chemical analyses, x-ray diffraction (XRD) infrared spectroscopy (IR) and differential scanning calorimetry (DSC). Their molecular and crystal structures are studied using transmission electron microscopy (TEM), cryo-TEM, electron diffraction (ED), electron paramagnetic spin resonance (EPR), absorption spectroscopy (UV-VIS), high resolution laser spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM), electron dispersive x-ray analysis (EDXA), thermal gravimetric analysis (TGA) and magnetic measurements. Models for the molecular and crystal structures of metallic soaps are proposed. The soaps are predominantly lamellar crystalline or liquid crystalline lamellar rotor phases with tilted and/or untilted molecular constituents. These display evidence of varying degrees of headgroup organisation, including superstructuring and polymerisation. A single crystal structure is presented for a complex of pyridine with cobalt soap. Simple models for their structure are discussed in terms of their swelling properties in water and oils. Experiments are also presented to demonstrate the sorbent properties of aluminium soaps on oil spills.¶ The thermotropic liquid crystallinity of alkaline earth, transition metal, heavy metal and lanthanide soaps is investigated in detail. This is done to assess their suitability as templates, and to document their novel thermotropic behaviour, particularly the relatively unknown lanthanide soaps. Liquid crystalline behaviours are studied using high-temperature XRD (HTXRD), hot-stage optical microscopy and DSC. Models for a liquid crystalline phase progression from crystals to anisotropic liquids are discussed in terms of theories of self-assembly and interfacial curvature. The terminology required for this is drawn from various nomenclature systems for amphiphilic crystals and liquid crystals. General agreement with previous studies is reported for known soaps, while liquid crystallinity is demonstrated in the lanthanide and some non-lanthanide soaps for the first time. A general phase progression of crystalline lamellar through liquid crystalline lamellar to non-lamellar liquid crystalline is discussed in terms of models concerned with the molecular and crystal structures of the soaps and their phase transitions via headgroup and chain re-arrangements.¶ Experiments aimed at guiding growth of metal sulfides using metallic soaps as templates are described, and a model for this growth is discussed. Metal sulfides have been successfully grown by reacting crystalline and liquid crystalline transition metal and heavy metal soaps with H2S gas at room temperature and at elevated temperature. These have been characterised using XRD, TEM, ED and IR. Sulfide growth is demonstrated to be restricted and guided by the reacting soap template architecture. Zinc, cadmium, indium and lead soaps formed confined nanoparticles within the matrix of their reacting soap template. In contrast, curved and flat sheet-like structures, some resembling sponges were found in the products of sulfided iron, cobalt, nickel, copper, tin and bismuth soaps. A model to explain this behaviour is developed in terms of the crystal and liquid crystal structures of the soaps and the crystal structures of the metal sulfide particles.¶ Liquid crystalline iron soaps have been subjected to controlled thermal degradation yielding magnetic iron oxide nanoparticles. Some XRD and TEM evidence has been found for formation of magnetic mesostructures in heat-treated iron soaps. Models for the molecular and liquid crystalline structure of iron soaps, their thermotropic phase progression and eventual conversion to these magnetic products are discussed. Systematic syntheses of mesoporous silicates from sheeted clays are discussed.¶The templates that have been used are cationic surfactants and small, organic molecular salts. Experiments are reported where a cooperative self-assembly of surfactant/water/kanemite plus or minus salt and oils yields 'folded sheet materials' (FSM'S). Templating of kanemite has also been achieved using cobalt cage surfactants. A theoretical prediction of the specific surface areas and specific volumes of homologous sets of FSM's gave excellent agreement with measured values. The geometry and topology of the mesostructures are discussed. A theoretical model is also discussed regarding the curvature found in the sheets of natural clays , and results of templating clays and silica using metallic soaps are presented. Experiments and a model for low temperature nucleation and growth of microporous silicalite-1 are described in terms of silica templating by water clathrates.¶ Finally, the problem of finding minimal surface descriptions of crystal networks is addressed. Combinatoric methods are used to disprove the existence of possible embeddings of type I and II clathrate networks in non-self intersecting periodic minimal surfaces. The crystal network of the clathrate silicate, melanophlogite is successfully embedded in the WI-10 self-intersecting surface. Details of a previously unreported, genus-25 periodic surface with symmetry Im3m are discussed.

The aim of this thesis work was to gain understanding of the interactions between talc mineral and surfaces, liquids and chemicals relevant for industrial applications, such as pulp and paper. Talc is used in the pulp and paper industry as a filler pigment, in control of pitch (lipophilic extractives) deposits and as a coating pigment. A deeper understanding of talc interactions will be beneficial in optimizing its use. Long-range attractive interactions between talc and hydrophobic model probes, as well as pitch probes, have been measured using the atomic force microscope (AFM) colloidal probe method. Two procedures for preparation of pitch colloidal probes were developed to allow these studies. Model hydrophobic, nanorough surfaces with surface energy characteristics similar to talc have also been prepared and their interactions with hydrophobic model probes compared to interactions between hydrophobic model probes and talc. It is demonstrated that talc mineral interacts with model hydrophobic particles, as well as with pitch, by long-range attractive forces, considerably stronger than the expected van der Waals force. The possible origin of the measured interaction forces is discussed, and the conclusion is that the main cause is an attractive capillary force due to formation of a gas/vapor capillary between the surfaces. Force measurements using model hydrophobic, nanorough surfaces show that a large-scale waviness does not significantly influence the range and magnitude of the capillary attraction, but large local variations in these quantities are found. It is demonstrated that a large variation in adhesion force corresponds to a small variation in local contact angle of the capillaries at the surfaces. The nature of the surface topographical features influences the capillary attraction by affecting the local contact angle and by pinning of the three-phase contact line. The effect is clearly dependent on the size of the surface features and whether they exist in the form of crevices or as extending ridges. Entrapment of air also affects the imbibition of water in pressed talc tablets. The effects of wetting and dispersion agents on the interactions between talc and hydrophobic probes have also been investigated. It is demonstrated that a common dispersing agent used for talc, poly(acrylic acid), does not affect the capillary attraction between talc and non-polar probes. In fact, the results strongly suggest that poly(acrylic acid) does not adsorb on the basal plane of talc. From this finding it is inferred that the stabilizing effect of this additive most likely is due to adsorption to the edges of talc. In contrast, a wetting agent (the non-ionic triblock copolymer Pluronic PE6400) removes the long-range capillary attraction. It is suggested that such an ability to replace air at the talc surface is of great importance for an efficient wetting agent. The Hamaker constant for talc has also been estimated by using optical data obtained from spectroscopic ellipsometry. It is demonstrated that a nanocrystalline talc mineral, cut in different directions displays very small differences in Hamaker constant between the different crystallographic orientations, whereas a microcrystalline sample displays a significantly higher value. The estimated Hamaker constants are discussed for different material combinations of relevance for the pulp- and paper industry, such as cellulose and calcium carbonate. / Målet med detta avhandlingsarbete var att öka förståelsen för interaktioner mellan talkmineral och ytor, vätskor och kemikalier relevanta för industriella applikationer, såsom papper och massa. Talk används i pappers- och massaindustrin som fyllmedel, för kontroll av hartsrika (lipofila extraktivämnen) avsättningar och som bestrykningspigment. En djupare förståelse för talkinteraktioner kommer att vara användbart för att optimera dess användning. Långväga attraktiva interaktioner mellan talk och hydrofoba modellpartiklar, såväl som mellan talk och hartspartiklar, har uppmätts med hjälp av atomkraftsmikroskopi (AFM) genom att fästa kolloidala partiklar på kraftsensorn. Två metoder för att framställa partiklar gjorda av harts har utvecklats för att möjliggöra dessa studier. Hydrofoba, nanostrukturerade modellytor med ytenergier liknande de för talk har också tillverkats och deras växelverkan med hydrofoba modellpartiklar har jämförts med dem mellan talk och hydrofoba modellpartiklar. Studierna visar att talkmineral växelverkar med hydrofoba modellpartiklar, såväl som med harts, genom långväga attraktiva krafter som är betydligt starkare än den förväntade van der Waals kraften. Möjliga orsaker till de uppmätta växelverkanskrafterna diskuteras och slutsatsen blir att huvudorsaken är en attraktiv kapillärkraft som uppkommer genom att en gas-/ångkapillär bildas mellan ytorna. Kraftmätningar gjorda med hydrofoba nanostrukturerade modellytor visar att en storskalig vågighet inte nämnvärt påverkar storleken av kapillärattraktionen, men stora lokala variationer existerar. Det demonstreras att en stor variation i adhesionskraft motsvaras av en liten variation i lokal kontaktvinkel för kapillärerna på ytorna. Ytornas topografi påverkar kapillärattraktionen genom att påverka den lokala kontaktvinkeln samt genom att trefaskontaktlinjen inte kan röra sig fritt över ytan. Effekten är tydligt beroende av huruvida ytojämnheterna existerar i form av nedsänkningar eller upphöjningar. Instängd luft påverkar också pressade talktabletters uppsugningsförmåga av vatten. Vätnings- och dispergeringsmedels inverkan på växelverkan mellan talk och hydrofoba partiklar har undersökts. Resultaten visar att ett vanligt dispergeringsmedel för talk, polyakrylsyra, inte påverkar kapillärattraktionen. I själva verket tyder data på att polyakrylsyra inte adsorberas på talks basalplan. Utifrån dessa resultat dras slutsatsen att polyakrylsyra stabiliserar talkdispersioner genom att adsorbera på talkkanterna. Ett vanligt vätmedel (nonjonisk triblock sampolymer Pluronic PE6400) tar å andra sidan bort långväga kapillärattraktion. Detta antyder att egenskapen att ersätta luft på talkytan är av stor betydelse för effektiva vätmedel. Hamakerkonstanten för talk har uppskattats genom att utnyttja optiska data från ellipsometrimätningar. Det demonstreras att ett nanokristallint talkmineral kapat i olika riktningar uppvisar mycket små skillnader i Hamakerkonstant mellan de olika kristallografiska orienteringarna, medan ett mikrokristallint prov uppvisar ett betydligt högre värde. De beräknade Hamakerkonstanterna diskuteras för olika materialkombinationer relevanta för pappersindustrin, såsom cellulosa och kalciumkarbonat. / QC 20100813

The influence of seven additives on the crystallization ability of polylactide (PLA), melt flow index (MVR) and mechanical tensile properties was studied. Pressed plates with a thickness of 0.8 mm were tested. Selected additives added in amounts of 0.5 and 1.0% were as follows: talc, sodium benzoate, mixtures of organic salts with amorphous SiO2 and zinc stearate, metal salt, phosphate salt, and potassium salt of 5-dimethylsulfoisophthalate (LAK-301 - nucleating agent developed for PLA). Non-isothermal crystallization measurements were performed at different cooling rates (0.3; 0.5; 0.7; 1.0 and 1.5 ° C). All nucleation agents increased the MVR of PLA except talc; the largest increase (9-fold and 24-fold) was the addition of metal salt. The additives did not fundamentally change the mechanical properties. All samples were rather brittle (the most brittle with LAK-301), the modulus of elasticity was around 1.2 GPa for all samples, the strength of PLA was increased the most by the addition of 1% talc (by 12%) and the elongation at break was increased by organic salt with SiO2. All samples with nucleating agents content of 1% were amorphous (crystalline content did not exceed 2%). Thus, the addition of reagents did not support the crystallization process during rapid cooling, even in the case of LAK-301. However, LAK-301 was acting as an excellent nucleating agent at slow cooling rates (1.5 °C / min and below). The nucleation activity of the additives decreased in the following order: LAK-301, organic salt with zinc stearate, talc, organic salt modified with amorphous SiO2 and phosphate salt. Samples with sodium benzoate and metal salt were crystallizing on cooling in several steps and it was not possible to use the method of Dobrev and Gutzow to evaluate the nucleation activity.

In the present work, novel dewatering aids and a novel centrifuge configuration were developed and applied for the purpose of dewatering fine particles. Three different types dewatering reagents were tested in different filtration and centrifugation units. These chemicals included low-HLB surfactants, naturally occurring lipids, and modified lipids. Most of these reagents are insoluble in water; therefore, they were used in solutions of appropriate solvents, such as light hydrocarbon oils and short-chain alcohols. The role of these reagents was to increase the hydrophobicity of the coal and selected mineral particles (chalcopyrite, sphalerite, galena, talc, clay, phosphate, PCC and silica) for the dewatering. In the presence of these reagents, the water contact angles on the coal samples were increased up to 90o. According to the Laplace equation, an increase in contact angle with the surfactant addition should decrease the capillary pressure in a filter cake, which should in turn increase the rate of dewatering and help reduce the cake moisture. The use of the novel dewatering aids causes a decrease in the surface tension of water and an increase in the porosity of the cake, both of which also contribute to improved dewatering. A series of batch-scale dewatering tests were conducted on a variety of the coal and mineral samples using the novel dewatering aids. The results obtained with a Buchner funnel and air pressure filters showed that cake moistures could be reduced substantially, the extent of which depends on the particle size, cake thickness, drying time, reagent dosage, conditioning time, reagent type, sample aging, water chemistry, etc. It was determined that use of the novel dewatering aids could reduce the cake formation time by a significant degree due to the increased kinetics of dewatering. At the same time, the use of the dewatering aids reduced the cake moistures by allowing the water trapped in smaller capillaries of the filter cake. It was found that final cake moistures could be reduced by 50% of what can be normally achieved without using the reagents. However, the moisture reduction becomes difficult with increasing cake thickness. This problem can be minimized by applying a mechanical vibration to the cake, spraying a short-chain alcohol on the cake and by adding a small amount of an appropriate coagulant, such as alum and CaCl2 to the coal and mineral slurries. The novel dewatering aids were also tested using several different continuous filters, including a drum filter, disc filter and horizontal belt filter (HBF). The results obtained with these continuous filtration devices were consistent with those obtained from the batch filters. Depending on the coal and mineral samples and the type of the reagent, 40 to 60% reductions in moisture were readily achieved. When using vacuum disc filters, the cake thickness increased substantially in the presence of the novel dewatering aids, which could be attributed to the increased kinetics of dewatering. A dual vacuum system was developed in the present work in order to be able to control the cake thickness, which was necessary to achieve lower cake moistures. It was based on using a lower vacuum pressure during the cake formation time, while a full vacuum pressure was used during the drying cycle time. Thus, use of the dual vacuum system allowed the disc filter to be used in conjunction with the novel dewatering aids. Its performance was similar to that of HBF, which is designed to control cake thickness and cake formation time independently. The effectiveness of using the novel dewatering aids were also tested in a full-continuous pilot plant, in which coal samples were cleaned by a flotation column before the flotation product was subjected to the disc filter. The tests were conducted with and without using novel dewatering aids. These results were consistent with those obtained from the laboratory and batch-scale tests. The novel centrifuge developed in the present work was a unit, which combined a gravity force and air pressure. The new centrifuge was based on increasing the pressure drop across the filter cake formed on the surface of the medium (centrifuge wall). This provision made it possible to take advantage of Darcy s law and improve the removal of capillary water, which should help lower the cake moisture. A series of tests were conducted on several fine coal and mineral particles and obtained more than 50% moisture reduction even at very fine particle size (2 mm x 0). Based on the test results obtained in the present work, two proof-of-concept (POC) plants have been designed. The first was for the recovery of cyclone overflows that are currently being discarded in Virginia, and the other was for the recovery of fines from a pond in southern West Virginia. The former was designed based on the results of the plant tests conducted in the present work. Cost vs. benefit analyses were conducted on the two POC plants. The results showed very favorable internal rates of return when using the novel dewatering aids. Surface chemistry studies were conducted on the coal samples based on the results obtained in the present investigation. These consisted mainly of the surface characterization of the coal samples (surface mineral composition, surface area, zeta potential, x-ray photoelectron microscopy (XPS)), acid-base interactions of the solids and liquids, dewatering kinetic tests, contact angle measurements of the coal samples and surface force measurements using AFM. In addition, carbon coating on a silica plate using palsed laser deposition (PLD) and Langmuir-Blodgett (LB) film deposition tests were conducted on the sample to better understand the surfactant adsorption and dewatering processes. The test results showed that the moisture reductions on the fine particles agree well with the surface chemistry results. / Ph. D.