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Alteration assemblage in the lower units of the Uitkomst Complex, Mpumalanga Province, South AfricaSteenkamp, Nicolaas Casper 03 September 2012 (has links)
The Uitkomst Complex is located within the Great Escarpment area close to the town of Badplaas, approximately 300 km due east of Pretoria, in the Mpumalanga Province, South Africa. This complex is believed to represent a layered conduit system related to the 2.06 Ga Bushveld Complex. The succession from the bottom up comprises the Basal Gabbro- (BGAB), Lower Harzburgite- (LHZBG) and Chromitiferous Harzburgite (PCR) Units, collectively referred to as the Basal Units, followed by the Main Harzburgite- (MHZBG), Upper Pyroxenite-(PXT) and Gabbronorite (GN) Units, collectively referred to as the Main Units. The Basal Unit is largely hosted by the Malmani Dolomite Formation, in the Pretoria Group of the Transvaal Supergroup sediments. The Lower Harzburgite Unit contains numerous calc-silicate xenoliths derived from the Malmani Dolomite. The Basal Units host the economically important nickel-bearing sulphide and chromite deposits exploited by the Nkomati Mine. An area of extensive localized talc-chlorite alteration is found in the area delineated for large scale open cast mining. This phenomenon has bearing on the nature and distribution of the sulphide minerals in the Chromitiferous Harzburgite and to a lesser extent the Lower Harzburgite Units. The Basal Unit is comprised of both near pristine areas of mafic minerals and areas of extensive secondary replacement minerals. Of the olivine minerals, only fosterite of magmatic origin is found, the fosterite suffered hydrothermal alteration resulting in replacement of it by serpentine and secondary magnetite. Three different types of diopside are found, the first is a primary magamatic phase, the second is a hybrid “transitional” phase and the third, a skarn phase. Hydrothermal alteration of the matrix diopside led to the formation of actinolite-tremolite pseudomorphs. This secondary tremolite is intergrown with the nickeliferous sulphide grains. Chromite grains are rimmed or replaced by secondary magnetite. Pyrrhotite grains is also rimmed or replaced by secondary magnetite. Talc and chlorite is concentrated in the highly altered rocks, dominating the PCR unit. Primary plagioclase and calcite do not appear to have suffered alteration to the same extent as the other precursor mafic magmatic and hydrothermal minerals. It is suggested that the PCR was the first unit to be emplaced near the contact of the dolomite and shale host rock. The more primitive mafic mineral composition and presence of chromitite attest to this interpretation. The LHZBG and MHZBG units may have been emplaced simultaneously, the LHZBG below and the MHZBG above. Interaction and partial assimilation of the dolomitic country rock led to a disruption of the primary mafic mineralogy, resulting in the preferential formation of diopside at the expense of orthopyroxene and plagioclase. Addition of country rock sulphur resulted in sulphur saturation of the magma and resulted in the observed mineralization. The downward stoping of the LHZBG magma, in a more “passive” pulse-like manner led to the formation of the calc-silicate xenolith lower third of this unit. It is proposed that the interaction with, and assimilation of the dolomitic host rock by the intruding ultramafic magmas of the Basal Units are responsible, firstly, for the segregation of the nickeliferous sulphides from the magma, and secondly for the formation of a carbonate-rich deuteric fluid that affected the primary magmatic mineralogy of the Basal Unit rocks. The fluids released during the assimilation and recrystallization of the dolomites also led to the serpentinization of the xenoliths themselves and probably the surrounding hybrid and mafic- ultramafic host rocks. The CO2-rich fluids migrated up and outward, while the H2O-rich fluids remained confined to the area around the xenoliths and LHZBG unit. The H2O-rich fluid is thought to be responsible for the retrograde metamorphism of the precursor magmatic and metamorphic minerals in the Lower Harzburgite Unit. The formation of an exoscarn within the dolomitic country rocks and a selvage of endoskarn on the contact form an effective solidification front that prevented further contamination of the magma. It is also suggested that these solidification fronts constrained the lateral extent of the conduit. The CO2-enriched deutric fluid was able to migrate up to the PCR unit. Here the fluid was not removed as effectively as in the underlying parts of the developing conduit. This resulted in higher CO2-partial pressures in the PCR unit, and the stabilization of talccarbonate assemblages that extensively replaced the precursor magmatic mineralogy. Intrusion of the magma into the shales, which may have been more susceptible to assimilation and greater stoping, led to a broadening in the lateral extent of the Complex, in the Main units above the trough-like feature occupied by the Basal Units. Late-stage, hydrous dominated fluid migration is inferred to have been constrained to the central part of the conduit. This is demonstrated by the dominance of chlorite in the central part of the Uitkomst Complex in the study area. The Uitkomst Complex was further deformed by later intrusions of dolerite dykes. Weathering of the escarpment led to exposure of the conduit as a valley and oxidation of the surficial exposed rocks. / Thesis (PhD)--University of Pretoria, 2012. / Geology / unrestricted
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Comparison of Indwelling Pleural Catheters and Chemical Pleurodesis Through Tube Thoracostomy for the Management of Malignant Pleural EffusionsSrour, Nadim January 2011 (has links)
BACKGROUND: Malignant and paramalignant pleural effusions are important complications of many malignancies. The two main management options debated in the literature are: 1) insertion of an indwelling pleural catheter (IPC) to achieve chronic drainage of the effusion, or 2) hospitalization with tube thoracostomy and subsequent chemical pleurodesis (CP) with talc or doxycycline to prevent fluid reaccumulation. We aimed to describe a large series of patients with malignant pleural effusions managed with an IPC, identify and validate factors identified in the literature as predictors of spontaneous pleurodesis in the IPC group and compare the group managed with IPC to patients managed with CP.
METHODS: We designed a retrospective cohort study comparing patients with malignant and paramalignant pleural effusions managed either with CP between March 1, 2003 and February 28, 2006 or IPC insertion between May 1, 2006 and April 1, 2009. The CP group was identified through the prescription of talc or doxycycline and the IPC group from the IPC clinic database. Data were collected from paper and electronic records and from the Government of Ontario.
RESULTS: We identified 193 consecutive patients with an ECOG performance status of less than 4 (ECOG less than 4 means that the patient is not completely disabled and confined to bed or chair) having undergone IPC insertion and 168 who were managed with CP. None of the variables we tested were significant predictors of spontaneous pleurodesis in the IPC group. Pleural effusion control rates at 6 months were higher in the IPC group than in the CP group (52.7% vs 34.0%, p<0.01) but the rate of freedom from pleural effusion at 180 days and catheter removal at 90 days was not significantly different (25.8% in the IPC group and 34.0% in the CP group p=0.14). Patients in the IPC group had a significantly longer median survival (148 days measured from the date of catheter insertion vs 133 days in the CP group, log-rank p<0.05).
CONCLUSION: We found an intriguing possible survival benefit favouring management of malignant or paramalignant effusions with an IPC. Given possible biases due to the design of this study and uncertain explanatory mechanism, this needs to be confirmed in a randomized controlled trial. Quality of life, an important measure of success for these palliative procedures, should also be measured.
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Seed coating, seed treatment, and temperature effects on germination of five seeded bermudagrass cultivarsLayton, John Morris 07 August 2010 (has links)
The use of improved seeded bermudagrasses (SB) has increased. All new cultivars are marketed as coated seed. As germination of many of these new cultivars is less than ideal, questions arise as to the effect coatings have on germination. Five SB cultivars were selected for a series of germination studies. The first study compared coated and uncoated samples of the five cultivars for germination response to six temperature regimes. Overall, commercial seed coating did not affect SB germination. However, both temperature regime and cultivar were significant factors. In a second study, three seed treatments were investigated across three temperature regimes and five SB cultivars to evaluate enhancement of germination. Two of the three treatments improved germination at day 7 indicating increased germination rate. No treatment produced significant results in germination at day 21. Cultivar specific differences regarding treatments were present at all count intervals.
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Geochemical Investigations of Respirable Particulate MatterJurinski, Joseph Bernard Jr. 22 July 1998 (has links)
Over the course of our lives we are exposed to airborne particulate matter in the workplace, home, and environment that results in the deposition of millions of particles in the lung. These exposures may result in disease if they are significant enough. The potential for harmful exposure depends in part on the dust's biodurability and the bioavailability of harmful constituents derived from the particles. A mixed flow reactor was used to evaluate two applications of geochemical methods to characterize the behavior of inhaled particles in the body. Dissolution rates of a well-characterized sample of powdered talc were measured in solvents that mimic fluids found in the human lung. These studies showed that variation of solvent chemistry, including the addition of organic chelators and proteins at intercellular fluid concentrations, does not markedly affect the measured dissolution rate of talc at 37 degrees Celcius and the data further indicate that the dissolution mechanism for talc in aqueous solutions is independent of pH over a range of pH from 2 to 8. The dissolution rate, determined by measuring the silicon release rate per unit surface area of talc is 1.4 (+/- 1.0) x 10-11 mol Si/(m2 -sec). A geometric shrinking particle model using this dissolution rate predicts an estimated lifetime (upper limit) of approximately 8 years for a 1 micron talc particle under pulmonary conditions. Talc dissolves considerably faster than quartz, but slower than chrysotile and olivine in the body. These data can be used to place constraints on the role of particle dissolution in the disease models associated with airborne respirable particulate matter.
Secondly, the bioavailability of As and Cr was determined from a sample of coal fly ash from an eastern U.S. power plant. The time-release profiles of As and Cr were determined for these materials in physiologically-based solvents and incorporated into a toxicokinetic model to predict the exposure potential to As and Cr from occupational exposures to the coal fly ash. Predicted occupational exposure contributions from the ash relative to total environmental exposures were insignificant. The exposure predicted from the geochemical approach was compared with results observed in a cohort occupationally exposed to coal fly ash and found to be within one order of magnitude of the response of the occupational cohort. These results support the application of geochemical techniques to evaluate exposures to complex respirable materials. / Ph. D.
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Determination of Surface Free Energies and Aspect Ratio of TalcLobato, Emilio Marcus de Castro 23 November 2004 (has links)
Microcalorimetric measurements and contact angle measurements were conducted to assess the surface chemistry of the mineral talc. The contact angles were performed on both flat and powdered samples and the results were used to determine the surface free energy components and parameters (SFEC) using the acid-base theory for solids, according to the van Oss-Chaudhury-Good approach. It was found that the surface hydrophobicity of talc increases with decreasing particle size up to a limit after which hydrophilicity (polarity) increases. The increase in hydrophobicity was attributed to the increase of the delamination of the lamellar talc particles. Delamination is a comminution mechanism that preferentially exposes talc's hydrophobic basal planes, while fracture is another mechanism that breaks the lamellae, rupturing covalent bonds thus exposing more hydrophilic edge surfaces. The decrease in hydrophobicity, beyond a given particle size, could be related to the prevail of fracture over delamination during grinding which generated more hydrophilic edge surfaces.
The flow microcalorymetry combined with thin layer wicking allowed the separate estimation of the SFEC at the basal plane and edge surfaces of talc. The results suggested that the basal surface of talc is monopolar basic, while the edge surface is monopolar acidic, which are in agreement with the crystal structure of the mineral.
The combination of two particle size distribution techniques, which are based on different physical principles, permitted the quantitative determination of the aspect ratio of highly anisometric particles, such as talc. The same trend obtained using flow microcalorimetry was observed for the evolution of the aspect ratio as a function of particle fineness, i.e. the fracture prevails over delamination after achieving a maximum aspect ratio value of about 35. The agreement between two distinct methods was considered rather encouraging. / Master of Science
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Films cellulaires en polypropylène chargé de talc et de carbonate de calcium utilisés comme matériaux piézoélectriques : optimisation de la structure cellulaire par étirage bi-axial et par gonglement sous atmosphère d'azoteAudet, Éric 23 April 2018 (has links)
Des films cellulaires pour usage piézoélectrique ont été développés par étirage bi-axial suivi d’un gonflement contrôlé à partir de films composites en polypropylène (PP) chargés de particules minérales: carbonate de calcium (CaCO3) et talc. Afin d’atteindre des propriétés piézoélectriques convenables, la morphologie cellulaire des films a été basée sur une revue de littérature pour l’épaisseur (b) des cellules, leur aspect (a/b) défini par le rapport entre leur longueur (a) et leur épaisseur (b), ainsi que l’épaisseur (t) de leurs parois. De façon à évaluer l’impact de la taille des particules, de leur concentration, de leur forme et de la température d’étirement sur la morphologie cellulaire de films, des échantillons ont été produits en extrudant des feuilles de 0,9 mm de PP/CaCO3 (12 μm, sphérique), PP/CaCO3 (6 μm, sphérique), PP/CaCO3 (3 μm, sphérique) et PP/talc (10 μm, plat). Ces feuilles ont été ensuite étirées bi-axialement à des températures de 152, 155, 158 et 160°C à un taux d’étirement de 2,4 m/min. Suite à l’étirement bi-axial, des épaisseurs de films variant entre 40 et 120 μm ont été obtenues. Les films ont ensuite subi un traitement d’expansion (diffusion d’azote à 130°C) afin de gonfler les cellules. L’analyse d’images obtenues par microscopie électronique à balayage (MEB) a servi à quantifier la morphologie cellulaire. Les résultats obtenus ont montré que les films de PP/CaCO3 (3 μm) n’ont pas donné de cellule, alors que ceux de PP/CaCO3 (12 μm) étirés à 152°C ont donné les meilleures morphologies cellulaires à des concentrations massiques de 35%. Ces «meilleures» morphologies correspondent à t = 3,6 μm, a/b = 5,6 et b = 13,6 μm. La valeur de la contrainte ultime lors de l’étirement s’est avérée proportionnelle à la quantité et à la qualité des cellules produites. Finalement, le ratio d’étirement, auquel la contrainte ultime est atteinte, est constant à environ 3,3, peu importe la taille des particules, leur concentration ou la température d’étirement. Ceci suggère que la matrice et la vitesse d’étirement sont responsables de la modulation du ratio d’étirement auquel la délamination matrice-particules se produit. Les travaux ont démontré que la concentration et la taille des particules sont inversement proportionnelles à l’épaisseur des parois cellulaires proportionnelles, au nombre de cellules observées et à la hauteur de ces cellules. L’abaissement de la température d’étirement a pour effet d’amplifier les effets respectifs associés à la taille et à la concentration des particules. / Piezoelectric cellular films have been developed, by bi-axial stretching followed by controlled cell inflation, from composite polypropylene (PP) films filled with mineral particles of calcium carbonate (CaCO3) and talc. An exhaustive literature review was done to identify the optimum values for the parameters describing the cellular structure promoting piezoelectricity. The most important morphological parameters associated with the structural stiffness of the films, which is inversely proportional to the piezoelectric coefficient, are: cell aspect ratio (a/b), cell thickness (b) and cell wall thickness (t). To optimize the cellular structure created during the bi-axial stretching step, PP films filled with CaCO3 and talc particles of different sizes and shapes were stretched at different temperatures and then underwent a gas diffusion expansion to improve the cell morphology. Initially, 0.9 mm sheets of PP/CaCO3 (12 μm, spherical), PP/CaCO3 (6 μm, spherical), PP/CaCO3 (3 μm, spherical) and PP/talc (10 μm, platy) were extruded before being bi-axially stretched at 152, 155, 158 and 160°C under a stretching rate of 2.4 m/min in both directions. The gas diffusion expansion treatment of the resulting films was done with nitrogen at 130°C. The cell morphology analysis was done from scanning electron microscopy (SEM) images to quantify a/b, b and t. It was observed that films made of PP/CaCO3 (3 μm) did not yield any cells. However, those made from PP/CaCO3 (12 μm) and stretched at 152°C had the best cellular structure when the CaCO3 concentration was 35% wt. The best morphology (t = 3.6 μm, a/b = 5.6 and b = 13.6 μm) was achieved within the targeted values to optimize piezoelectric properties. It was found that the ultimate stress during stretching depends on the cellular quality of the resulting film and that, independent of the size of CaCO3 or talc particles, their concentration or the stretching temperature. It was also observed that the stretching ratio at which the ultimate stress was obtained was always around 3.5. This suggested that both the stretching speed and the polymer matrix were responsible for the stretching ratio at which delamination occurs. As expected, particle concentration and their size were shown to be inversely proportional to cell wall thickness, but proportional to the number of cells observed and to their height. Decreasing the stretching temperature amplified the respective effects of the cell morphology associated with particles size and concentration.
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Etude de la cristallisation du PLA : Effets d’agents de nucléation et de l’écoulement sur les cinétiques et morphologies cristallines / Study of the PLA crystallization : Effects of nucleating agent and flow on the crystallization kinetics and morphology developmentRefaa, Zakariaa 09 December 2015 (has links)
Le Polylactide est un polymère biosourcé et biodégradable. Il représente un alternatif potentiel pour certains polymères issus de l’industrie pétrochimique. Néanmoins, il présente une cinétique de cristallisation lente. Dans ce travail, une attention particulière a été portée à la compréhension et la modélisation de la cinétique de cristallisation et la morphologie cristalline induite du PLA. Dans un premier temps, nous avons étudié la cristallisation en conditions statiques du PLA avec et sans agent de nucléation «talc». L’effet du polymorphisme sur les paramètres du modèle d’Avrami est modélisé en conditions isothermes, ensuite la morphologie cristalline induite en fonction de degré de surfusion est discutée pour le PLA avec et sans talc. Dans un second temps, l’effet de la température, le taux et le temps de cisaillement sur la cinétique de cristallisation du PLA et la morphologie cristalline induite est analysée, et la contribution de l’écoulement dans la germination est modélisée. La synergie entre le cisaillement et les particules de talc dans l’amélioration de la cinétique de cristallisation est démontrée par la quantification de la germination thermiquement induite et celle induite par le cisaillement. Enfin, dans le cadre du procédé d’injection, nous avons étudié l’effet de l’histoire thermomécanique et du talc sur les propriétés mécaniques du PLA. L’analyse effectuée a porté sur l’effet des paramètres du procédé d’injection et du talc sur le module de flexion en relation avec la cristallinité induite dans les pièces injectées. / The Polylactide is a biobased, biodegradable polymer. It represents a potential alternative for some polymers from the petrochemical industry. Nevertheless, it has a slow crystallization kinetics. In this work, special attention was paid to the understanding and modeling of the crystallization kinetics and morphology induced crystalline PLA. First, we investigated the crystallization of PLA in static conditions with and without nucleating agent "talc". The effect of the polymorphism on the parameters of the Avrami model is modeled in isothermal conditions, then the induced crystalline morphology as a function of degree of supercooling is discussed for PLA with and without talc. In a second step, the effect of temperature, the rate and the shearing time on the crystallization kinetics of the PLA and the resulting crystal morphology is analyzed, and the contribution of the flow in the germination is modeled. The synergy between the shear and the talc particles in improving the crystallization kinetics is demonstrated by quantification of germination thermally induced and that induced by shear. Finally, as part of the injection process, we studied the effect of thermomechanical history and talc on the mechanical properties of PLA. The analysis focused on the effect of parameters of the injection process and talc on the flexural modulus in relation to the induced crystallinity in the molded parts.
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Etude de l'impact des vieillissements photochimique, thermique et climatique sur les propriétés d'aspect de polypropylènes teintés masse colorés / Study of impact of photochemical, thermal and climatic aging on appearance properties of mass-coloured polypropyleneRouillon, Camille 07 December 2015 (has links)
Sous l’impact de contraintes photochimiques, thermiques, et hydrolytiques, les polymères subissent une dégradation souvent irréversible de leurs propriétés fonctionnelles. L’étude des mécanismes à l’origine de cette dégradation est indispensable pour la compréhension des phénomènes mis en jeu à toutes les échelles et pour la prévision de la durée de vie du matériau. L’enjeu de cette thèse est de comprendre les mécanismes à l’origine de la perte des propriétés d’aspect de matériaux en polypropylène teinté dans la masse soumis à un vieillissement photochimique, en suivant une approche multi-échelles et multi-critères. La composition des matériaux a été progressivement complexifiée au cours de l’étude, afin de pouvoir comprendre l’influence de l’ajout de pigments organiques, de stabilisants, et de talc, sur les modifications d’aspect des pièces sous irradiation. Grâce aux résultats obtenus et aux valeurs-seuils alors définies pour chaque critère de dégradation identifié, un modèle analytique d’étude du vieillissement de pièces en polypropylène teinté dans la masse a pu être proposé. / Under photochemical, thermal and hydrolytic stresses, polymers undergo an often-irreversible degradation of their functional properties. The study of the mechanisms governing the degradation of the properties is important, and understanding the involved phenomena at every scale is mandatory to predict the material lifetime. This PhD thesis aims at understanding the mechanisms underlying the loss of appearance properties of mass coloured polypropylene materials, using a multi-scale and multi-criteria approach. Formulations were progressively made more complex during this study, in order to understand the influence of organic pigments, stabilizers, and talc, on the appearance changes of the material under exposure. Thanks to the obtained results and to the threshold values determined for each identified criterion during degradation monitoring, an analytical model to study mass coloured polypropylene ageing could be proposed.
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Development of novel bio-derived polymer composites reinforced with natural fibres and mineral fillersShakoor, Abdul January 2013 (has links)
Biocomposites exhibit properties like many petrochemical-based polymers composites. They have the potentials be used in the automotive and decking industries and as biodegradable packaging. However, the high cost as well as, poor mechanical and thermal properties have restricted their widespread use. There are a number of technical issues that need to be addressed before bio-composites can be widely used. In this research Polylactic acid (PLA) composites, reinforced with natural fibres (wood, flax) and mineral fillers (talc) were investigated. The thermal and mechanical properties of the composites were studied by means of Differential Scanning Calorimetry (DSC), Tensile Testing and Dynamic Mechanical Analysis (DMA), while morphology and crystallization processes of the composites were studied by hot stage optical microscopy. The experimental results are also compared with different theoretical models of the response of the composites. PLA / wood composites were developed by mixing PLA with wood in different ratios using a melt compounding process. PLA/wood (90/10. 80/20, 60/40), PLA/wood/copolymers (85/10/05, 80/10/10, 75/20/05, 70/20/10, 55/40/05, 50/40/10) and PLA/wood/coupling agent (80/20/silane coating) were the three different composite systems that were developed. Adding increasing amount of wood into the PLA, the thermal properties remain unchanged but the mechanical properties increased significantly, bringing a stiffening effect to the composites. Tensile modulus increased from 4.1± 0.6 to 9.8 ± 1.2 (GPa) as the wood content increased from 0 to 40 (wt %), but the tensile strength at break reduced from 43.8 ± 3.1 to 31.8 ± 2.8 MPa. The experimental results of the PLA-wood composites were modelled according to the Halpin-Tsai equation. The addition of copolymer affected the thermal properties considerably by decreasing the glass transition temperature of the composite. The glass transition temperature dropped from 54 ± 0.7 (0C) to 48 ± 0.36 (0C) when the content of copolymer was increased from 0 to 10 (wt %). The cold crystallization temperature also decreased from 127 ± 1.41 (0C) to 103 ± 2.58 (0C) when the copolymer was incorporated into the PLA/wood composites. The significant aspect was the occurrence of a double peak in the melting endotherm. The degree of crystallinity also increased from 2 ± 0.83 (%) to 11 ± 1.23 (%) when the amount of copolymer was increased to 10 (wt %). PLA, flax and expoidizied natural rubber (ENR) composites were also developed using a melt compounding process. The mechanical properties were affected significantly when the flax fibres were mixed with PLA in the ratios of 10, 20 and 30 (wt %). Addition of flax fibres increased the elastic modulus significantly but reduced the tensile strength and strain at break. To improve the toughness of the PLA- Flax composites, ENR was incorporated into the PLA- Flax composites. In order to balance the modulus of the reinforcement and the matrix, the PLA- Flax and ENR composites were annealed above the glass transition temperature and the degree of crystallinity increased from 2 to 35 (%). The integral blending of PLA, Flax and ENR did not affect the brittle fracture but introducing a masterbatch of flax fibres and ENR into the PLA matrix during melt processing had a considerable effect on the fracture behaviour of the composites. The elastic modulus of the composites decreased due to the elastomeric content in the composites and there was an increase in elongation-to-break. The effect of talc on the crystallinity and mechanical properties of a series of polylactic acid (PLA) / talc composites was investigated. PLA talc composites were developed by incorporating different types of the talc into the PLA in the ratios of 10, 20 and 30 (wt %). The composites were prepared by melt blending followed by compression moulding. It was found that talc acted as a nucleating agent and increased the crystallinity of the PLA from 2% to 25%. There was significant improvement in Young s modulus of the composites with increasing talc addition and these results were found to fit the Halpin Tsai model. Thermo-mechanical tests confirmed that the combination of increased crystallinity and storage modulus leads to improvement in the heat distortion properties.
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Talkum-PleurodeseLuplow, Silke 03 February 2006 (has links)
Die Talkumpleurodese stellt ein effektives Verfahren zur Behandlung von rezidivierenden malignen Pleuraergüssen dar. Sie ist ein rein palliatives Verfahren. Das Auftreten des malignen Pleuraergusses stellt den Beginn des letzten Lebensabschnittes eines Tumorpatienten dar. Es ist verbunden mit dem Kardinalsymptom Dyspnoe. Um diese zu lindern, wird im blinden Aktionismus die operative Pleurodese angeboten. Dieses führt zu einer hohen perioperativen Mortalität. In 36 Monaten (1997-1999) wurden in unserer Klinik 115 operative Talkum-Pleurodesen durchgeführt. Die perioperative Letalität lag bei 7,8 %. Die häufigsten Primärtumoren waren Mammakarzinom (MÜL 12,4 Monate), Bronchialkarzinm (MÜL 6,2 Monate), CUP (MÜL 10,7 Monate) Ovarialkarzinom (MÜL 2,2 Monate) und Mesotheliom (MÜL 10,9 Monate). Die Patienten mit Mammakarzinom, Bronchialkarzinom und Ovarialkarzinom litten postoperativ deutlich gehäufter unter erneuter Luftnot. Es ist daher nötig, Standards festzulegen, um ein geeignetes Patientengut zu behandeln. In der Literatur finden sich eindeutige Zusammenhänge zum Karnofsky-Index des Patienten sowie zu den Laborparametern pH (kritisch / Talc pleurodesis is the most effective treatment für malignant pleural effusions. It is a palliative procedure. The appearance of a malignant pleural effusions marks the beginning of the last part of life of a patient with cancer. The cardinal symptom is dyspnoea. To allay, we offer surgical pleurodesis, offen in blind action. This is causing high mortality. We performed 115 thoracoscopic talc pudrages between 1997 and 1999 (36 month). The inpatient mortality was 7,8%. The most offen origins of metastatic carcinoma were Breast cancer (MS 12,4 month), Lung cancer (MS 6,2 month), Carcinoma of unknown primary (MS 10,7 month), Malignant mesothelioma (MS 10,9 month) and Ovarian cancer (MS 2,2 month). The patients with Breast-, Lung- and Ovarian cancer suffered the must from dyspnoea after pleurodesis. That''s why it is necessary, to find standards to choose suitable patients, which profit. In literature there are definite connection between Karnofsky Performance Scale of a patient, pleural fluid pH (critically
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