Ce travail a pour but d’étudier les paramètres physico-chimiques qui contrôlent les transferts de matière ainsi que la formation et l’évolution des argiles dans des failles chevauchantes en environnement sédimentaire. Deux failles chevauchantes pyrénéennes de faible grade métamorphique ont été étudiées : la faille de Millaris (cf. Mont Perdu) et le chevauchement du Pic-de-Port-Vieux (cf. Gavarnie). Dans la faille de Millaris, la déformation s’accompagne principalement d’une dissolution de la calcite matricielle par pression-solution induisant un changement de volume de la roche de 20 à 40%. Le chevauchement du Pic-de-Port-Vieux enregistre des modifications importantes au coeur de la faille mais aussi dans la zone d’endommagement. Dans les calcaires du mur du chevauchement, une mylonitisation est associée à une dissolution partielle des dolomites en présence de fluides ne dépassant pas 320-340°C. Dans les pélites du toit du chevauchement, la dissolution de l’hématite par un fluide réducteur entraine un changement de l’état redox de la roche (confirmé par spectroscopie Mössbauer) et la précipitation de chlorite dans des veines syncinématiques. Des chlorites à zonations chimiques oscillatoires présentes dans certaines veines révèlent, en combinant cartographie chimique à la microsonde, mesures de l’état redox par μXANES et thermométrie, des variations cycliques de température d’au moins 50°C au cours de la cristallisation. Un processus de valves sismiques pourrait donc être associé à la mise en place du chevauchement du Pic de Port Vieux. / This work aims to study the physical and chemical parameters that control the mass-transfer and the clays formation and evolution in sedimentary environment thrust faults. Two Pyrenean thrust faults in low metamorphic grade were studied: the Millaris fault (related to Mont Perdu) and the Pic-de-Port-Vieux thrust (related to Gavarnie). In the Millaris fault, the deformation is accompanied mainly by dissolution of the matrix calcite by pressure-solution which induces a volume change of the rock from 20 to 40%. The Pic-de-Port-Vieux thrust records significant changes in the fault core-zone, but in the damaged zone also. In the footwall limestone, a mylonitisation is associated with a partial dissolution of dolomite in the presence of not exceeding 320-340°C fluids. In the hanging-wall pelites, the hematite dissolution by a reducing fluid causes a redox state change of the rock (confirmed by Mössbauer spectroscopy) and chlorite precipitation in synkinematic veins. Oscillatory zoning pattern chlorites located in some shearing veins revealed, by combining chemical mapping microprobe, redox state measurements with μ-XANES and thermometry, cyclic temperature variations of at least 50°C during the crystallization. A seismic valves process could be associated to Pic-de-Port-Vieux thrusting.

A Nappe Lima Duarte, localizada na porção oriental do sistema orogênico Tocantins Meridional, sudoeste do estado de Minas Gerais, é constituída por rochas supracrustais de alto grau (gnaisses e micaxistos com e sillimanita e quartzitos) com lascas de ortognaisses arqueanos tonalíticos - granodioríticos (antigos terrenos TTG) tectônicamente intercaladas. É nesta Nappe de Lima Duarte que ocorrem os dois corpos metaultramáficos tema deste estudo. O corpo ultra máfico de Lima Duarte, bandado - estratificado, sem foliação evidente, encontra-se encaixado em uma zona de cisalhamento entre hornblendabiotita gnaisses e migmatitos, e sillimanita - muscovita - biotita - quartzo xistos/gnaisses. Trata-se de um corpo lenticular alongado em direção NW - SE, com 700 metros de comprimento e aproximadamente 300 metros de largura. Já o corpo ultramáfico de Olaria aflora como um conjunto de blocos anguloso de alguns metros de tamanho, e ocorre como corpo lenticular pequeno encravado em hornblenda - biotita ortognaisses. Em ambos corpos o grau de intemperismo impossibilita estabelecer as relações de contato com as rochas encaixantes. O corpo de Lima Duarte apresenta bandamento composicional como relíquia ígnea, indicando que se trata do fragmento de um corpo bandado - estratificado desmembrado. Seus litotipos, que ocorrem alternados em bandas centimétricas, são constituídos por proporções variáveis de olivina, ortopiroxênio, magnésio-hornblenda, espinélio / magnetita, Mg-clorita e serpentina e, considerando a Mg-hornblenda como substituta do clinopiroxênio ígneo, representam metadunitos, metaharzburgitos, meta-olivina- ortopiroxenitos e metalherzolitos, serpentinizados com intensidade variável. O corpo de Olaria apresenta texturas grano-nematoblásticas poligonizadas a lobadas, e é constituído de ortopiroxênio e hornblenda - espinélio + Mg-clorita + olivina, com serpentinização apenas incipiente em olivina. Os minerais do corpo de Lima Duarte são mais magnesianos (Mg/Mg+Fe2+mais altos, hornblenda e ortopiroxênio sem pleocroísmo), enquanto os de Olaria são mais ricos em ferro (Mg/Mg+Fe2+mais baixo, ortopiroxênio e hornblenda pleocróicos), sugerindo protólitos mais magnesianos para Lima Duarte. As texturas e paragêneses metamórficas (ortopiroxênio - olivina - Mg-hornblenda - Mg-Al-espinélio, + Mg-clorita) sugerem condições de limiar fácies anfibolito-fácies granulito. A evolução metamórfica é modelada com base nas variações composicionais que ocorrem no anfibólio cálcico e na Mg-clorita. A quebra final da Mg-clorita, definida pela reação: Mg-Clorita forsterita + enstatita + espinélio + H20, representa as condições de pico alcançadas, com reconstituição parcial retrometamórfica da clorita. . Estimativas termobarométricas com o programa Thermocalc para a paragênese olivina - ortopiroxênio - espinélio - hornblenda forneceram temperaturas de 810ºC para o corpo de Lima Duarte e 840ºC para o de Olaria, compatíveis com as estimativas citadas na literatura para as rochas encaixantes e com as condições de quebra da Mg-clorita. No corpo de Lima Duarte, a intensa serpentinização ocorreu inicialmente através e substituições por domínios composicionais, resultando em texturas pseudomórficas de olivina (mesh) e ortopiroxênio (bastita), tornando-se mais pervasiva a seguir, com serpentinização da hornblenda e clorita, implicando mobilidade de Ca e Al no sistema. / The ultramafic rocks of this study occur in the Lima Duarte nappe, which is constituted of high-grade metassedimentary rocks such as sillimanite schists and gneisses as well as quartzites, with intercalated tectonic slices of tonalitic-granodioritic gneisses and migmatites from the archean TTG basement. This nappe belongs to the eastern part of the southern Tocantins Orogenic system, in southwestern Minas Gerais State, Brazil. The ultramafic rocks make up two bodies in the Lima Duarte nappe. The Lima Duarte body is stratified, without foliation, included in a shear zone between sillimanite-garnet schists and gneisses and hornblende-biotite gneisses and migmatites as a lenticular body approximately 700 m long and 300 m thick. The Olaria body outcrops as a few meter-size boulders, possibly as a lenticular body intercalated in hornblende-biotite orthogneisses. Neither body exhibits its contacts with the country rocks due to the intense weathering. The Lima Duarte body exhibits layering inherited from stratified igneous rocks, and thus represents a fragment of a dismembered stratified igneous complex. It´s rock types, constituted by varying proportions of olivine, orthopyroxene, magnesian hornblende, green spinel, magnetite, Mg-chlorite and serpentine, occur alternated in centimetric bands and, if hornblende is taken as correspondent to clinopyroxene, can be identified as metadunites, meta-olivine orthopyroxenites, metaharzburgites and metalherzolites, all serpentinized in various degrees. The Olaria body exhibits grano-nematoblastic, polygonized to lobate textures, and is constituted by orthopyroxene - hornblende - green spinel + olivine + Mg-chlorite, with incipient serpentinization in olivine grains. The Lima Duarte rocks are more magnesian (higher Mg/Mg+Fe2+ in minerals, non-pleochroic orthopyroxene and hornblende) than the ones from Olaria (lower Mg/Mg+Fe2+ in minerals, pleochroic hornblende and orthopyroxene). The metamorphic textures and parageneses (olivine - orthopyroxene - hornblende - Mg-Al-spinel + Mg-chlorite) suggest metamorphic conditions transitional from amphibolites to granulite facies, with late low-grade serpentinization in the Lima Duarte body. The metamorphic evolution is modeled through continuous compositional changes in calcic amphibole and Mg-chlorite. The final breakdown of chlorite, through the reaction: Mg-chlorite olivine + orthopyroxene + spinel + H2O represents peak conditions, with later partial retrometamorphic reconstitution of chlorite. Thermobarometric estimates for the paragenesis orthopyroxene - hornblende - olivine - spinel with the help of Thermocalc yielded 810oC for Lima Duarte rocks and 840oC for Olaria rocks, in good agreement with previous results for the high-grade country rocks from literature and for the chlorite breakdown conditions. In the Lima Duarte body, the intensive serpentinization started with compositional domain substitutions, mainly in olivine and orthopyroxene, resulting in pseudomorphic textures (mesh and bastite, respectively). In later stages, calcic amphibole as well as chlorite suffered serpentinization, thus indicating Ca and Al mobility in the system.

A Nappe Lima Duarte, localizada na porção oriental do sistema orogênico Tocantins Meridional, sudoeste do estado de Minas Gerais, é constituída por rochas supracrustais de alto grau (gnaisses e micaxistos com e sillimanita e quartzitos) com lascas de ortognaisses arqueanos tonalíticos - granodioríticos (antigos terrenos TTG) tectônicamente intercaladas. É nesta Nappe de Lima Duarte que ocorrem os dois corpos metaultramáficos tema deste estudo. O corpo ultra máfico de Lima Duarte, bandado - estratificado, sem foliação evidente, encontra-se encaixado em uma zona de cisalhamento entre hornblendabiotita gnaisses e migmatitos, e sillimanita - muscovita - biotita - quartzo xistos/gnaisses. Trata-se de um corpo lenticular alongado em direção NW - SE, com 700 metros de comprimento e aproximadamente 300 metros de largura. Já o corpo ultramáfico de Olaria aflora como um conjunto de blocos anguloso de alguns metros de tamanho, e ocorre como corpo lenticular pequeno encravado em hornblenda - biotita ortognaisses. Em ambos corpos o grau de intemperismo impossibilita estabelecer as relações de contato com as rochas encaixantes. O corpo de Lima Duarte apresenta bandamento composicional como relíquia ígnea, indicando que se trata do fragmento de um corpo bandado - estratificado desmembrado. Seus litotipos, que ocorrem alternados em bandas centimétricas, são constituídos por proporções variáveis de olivina, ortopiroxênio, magnésio-hornblenda, espinélio / magnetita, Mg-clorita e serpentina e, considerando a Mg-hornblenda como substituta do clinopiroxênio ígneo, representam metadunitos, metaharzburgitos, meta-olivina- ortopiroxenitos e metalherzolitos, serpentinizados com intensidade variável. O corpo de Olaria apresenta texturas grano-nematoblásticas poligonizadas a lobadas, e é constituído de ortopiroxênio e hornblenda - espinélio + Mg-clorita + olivina, com serpentinização apenas incipiente em olivina. Os minerais do corpo de Lima Duarte são mais magnesianos (Mg/Mg+Fe2+mais altos, hornblenda e ortopiroxênio sem pleocroísmo), enquanto os de Olaria são mais ricos em ferro (Mg/Mg+Fe2+mais baixo, ortopiroxênio e hornblenda pleocróicos), sugerindo protólitos mais magnesianos para Lima Duarte. As texturas e paragêneses metamórficas (ortopiroxênio - olivina - Mg-hornblenda - Mg-Al-espinélio, + Mg-clorita) sugerem condições de limiar fácies anfibolito-fácies granulito. A evolução metamórfica é modelada com base nas variações composicionais que ocorrem no anfibólio cálcico e na Mg-clorita. A quebra final da Mg-clorita, definida pela reação: Mg-Clorita forsterita + enstatita + espinélio + H20, representa as condições de pico alcançadas, com reconstituição parcial retrometamórfica da clorita. . Estimativas termobarométricas com o programa Thermocalc para a paragênese olivina - ortopiroxênio - espinélio - hornblenda forneceram temperaturas de 810ºC para o corpo de Lima Duarte e 840ºC para o de Olaria, compatíveis com as estimativas citadas na literatura para as rochas encaixantes e com as condições de quebra da Mg-clorita. No corpo de Lima Duarte, a intensa serpentinização ocorreu inicialmente através e substituições por domínios composicionais, resultando em texturas pseudomórficas de olivina (mesh) e ortopiroxênio (bastita), tornando-se mais pervasiva a seguir, com serpentinização da hornblenda e clorita, implicando mobilidade de Ca e Al no sistema. / The ultramafic rocks of this study occur in the Lima Duarte nappe, which is constituted of high-grade metassedimentary rocks such as sillimanite schists and gneisses as well as quartzites, with intercalated tectonic slices of tonalitic-granodioritic gneisses and migmatites from the archean TTG basement. This nappe belongs to the eastern part of the southern Tocantins Orogenic system, in southwestern Minas Gerais State, Brazil. The ultramafic rocks make up two bodies in the Lima Duarte nappe. The Lima Duarte body is stratified, without foliation, included in a shear zone between sillimanite-garnet schists and gneisses and hornblende-biotite gneisses and migmatites as a lenticular body approximately 700 m long and 300 m thick. The Olaria body outcrops as a few meter-size boulders, possibly as a lenticular body intercalated in hornblende-biotite orthogneisses. Neither body exhibits its contacts with the country rocks due to the intense weathering. The Lima Duarte body exhibits layering inherited from stratified igneous rocks, and thus represents a fragment of a dismembered stratified igneous complex. It´s rock types, constituted by varying proportions of olivine, orthopyroxene, magnesian hornblende, green spinel, magnetite, Mg-chlorite and serpentine, occur alternated in centimetric bands and, if hornblende is taken as correspondent to clinopyroxene, can be identified as metadunites, meta-olivine orthopyroxenites, metaharzburgites and metalherzolites, all serpentinized in various degrees. The Olaria body exhibits grano-nematoblastic, polygonized to lobate textures, and is constituted by orthopyroxene - hornblende - green spinel + olivine + Mg-chlorite, with incipient serpentinization in olivine grains. The Lima Duarte rocks are more magnesian (higher Mg/Mg+Fe2+ in minerals, non-pleochroic orthopyroxene and hornblende) than the ones from Olaria (lower Mg/Mg+Fe2+ in minerals, pleochroic hornblende and orthopyroxene). The metamorphic textures and parageneses (olivine - orthopyroxene - hornblende - Mg-Al-spinel + Mg-chlorite) suggest metamorphic conditions transitional from amphibolites to granulite facies, with late low-grade serpentinization in the Lima Duarte body. The metamorphic evolution is modeled through continuous compositional changes in calcic amphibole and Mg-chlorite. The final breakdown of chlorite, through the reaction: Mg-chlorite olivine + orthopyroxene + spinel + H2O represents peak conditions, with later partial retrometamorphic reconstitution of chlorite. Thermobarometric estimates for the paragenesis orthopyroxene - hornblende - olivine - spinel with the help of Thermocalc yielded 810oC for Lima Duarte rocks and 840oC for Olaria rocks, in good agreement with previous results for the high-grade country rocks from literature and for the chlorite breakdown conditions. In the Lima Duarte body, the intensive serpentinization started with compositional domain substitutions, mainly in olivine and orthopyroxene, resulting in pseudomorphic textures (mesh and bastite, respectively). In later stages, calcic amphibole as well as chlorite suffered serpentinization, thus indicating Ca and Al mobility in the system.

Microbial chlorate respiration plays an important role in the turnover of oxochlorates in nature and industrial waste management. This thesis deals with the characterization of the molecular components of chlorate respiration in Ideonella dechloratans. Chlorate respiration utilizes two soluble periplasmic enzymes, chlorate reductase and chlorite dismutase, to convert chlorate to chloride and oxygen. The genes encoding the enzymes participating in the chlorate degradation have been sequenced, and are found in close proximity, forming a gene cluster for chlorate metabolism. This work also includes the successful recombinant expression of three genes from Ideonella dechloratans. Two of the gene products, chlorite dismutase and the C subunit of chlorate reductase, participate in the chlorate respiration. The third gene, which is found close to the gene cluster for chlorate metabolism, encodes a soluble c-type cytochrome. The localization of the gene suggests the corresponding protein as a candidate for a role as electron donor to chlorate reductase. Also, the role of soluble periplasmic c cytochromes of Ideonella dechloratans in chlorate respiration was studied. At least one of the soluble c cytochromes was found capable of serving as electron donor for chlorate reduction. This c cytochrome, and several others, can also donate electrons to a terminal oxidase for subsequent reduction of oxygen, as required for the branched electron flow during chlorate respiration.

Células tronco hematopoéticas (CTH) de sangue de cordão umbilical (SCU) possuem grande potencial em terapia celular. Mesmo sendo bem caracterizadas quanto às suas propriedades funcionais e fenotípicas, a regulação da auto-renovação de CTH e os genes envolvidos são pouco conhecidos. Investigou-se através da curva de crescimento, ensaio clonogênico e citometria de fluxo, a expansão e diferenciação de CTH cultivadas sem e com suplementação dos mitógenos estradiol e LiCl. A expressão da subunidade da telomerase teve aumento significativo em todas as condições, bem como a expressão de Nanog e Oct4 relacionados a pluripotência e auto-renovação. Observou-se também a expressão de Nanog, Oct4, Sox2 e FoxD3 em células CD133, células CD3 de sangue periférico e células de colônias hematopoéticas. Concluiu-se que o meio sem suplementação já é suficiente na expansão de CTH, mantendo suas características, relacionadas à proliferação, auto-renovação e pluripotência celular. / Hematopoietic stem cells (HSC) from umbilical cord blood (UCB) have a great potencial for hematopoietic reconstitution. Although these stem cells have been well characterized by their functional and fenotipics properties, self-renewal regulation and genes involved are still unknown. Analyses of cell growth, clonogenic assay and flow cytometry revealed the expansion and differentiation of HSC grown in medium with or without suplementation of the mitogens estradiol and LiCl. Expression of the subunit of telomerase increased in all treatments. As well as the expression of Nanog and Oct4, related to plutipotency and self-renewal. Nanog, Oct4, Sox2 and FoxD3 expression was also high in CD133 cells, in CD3 cells from peripherical blood and in clonogenic assay derived cells. Conclusion: medium without the suplementation is sufficient for expansion of HSC, keeping their characteristcs, realted to proliferation, self-renewal and pluripotency.

L'ensemble Silurien supérieur-Dévonien inférieur du Bassin de Ghadamès, équivalent du réservoir F6 du bassin d'illizi, est subdivisé en cinq unités (a, b, c, d, e) couvrant l'intervalle de temps du Ludlowien au Praguien sans discontinuité sédimentaire. L'analyse des faciès et la stratigraphie séquentielle ont permis de caractériser les milieux de dépôts et de retracer l'histoire spatio-temporelle des sédiments. Les sédiments argilo-gréseux, de l'unité "a" (Ludlowien - Pridolien) forment le prisme de haut niveau (PHN) de la séquence S1 (Ordovicien supérieur - Silurien supérieur); ils caractérisent une zone littorale dominée par l'action des vagues et des tempêtes. Les Grès massifs "b" (Lochkovien), prisme de bas niveau (PBN) de la séquence S2 (éodévonienne), sont constitués de dépôts fluviatiles de remplissage de vallées entaillées (IVF) au Sud du bassin (région Stah/Méreksen) et de dépôts de plaine côtière formant des prismes de progradation (LPW) en direction du bassin (Nord). Les sédiments ferrugineux de l'unité "C" (Lochkovien) sont des dépôts marins transgressifs (TST). Les sédiment de l'unité "d" (Praguien) et de l'unité "e" (Emsien) sont des dépôts de haut niveau marin (PHN) de la séquence S2. Les réservoirs rencontrés dans le Bassin de Ghadamès sont situés principalement dans les unités "b" et "c" (Lochkovien) où l'extension des grès est prouvée sur des milliers de km2 Par contre les réservoirs présentent des variations de porostté et de perméabilité, engendrées par les transformations diagénétiques qui ont affecté les grès. Le revêtement chloriteux des grains, ciment précoce, préserve la porosité intergranulaire et protège les grains des phénomènes diagénétiques ultérieures. Les grains épargnés par la chlorite, vont subir au cours de l'enfouissement des silicifications intense et la précipitation des ciments sulfatés et carbonatés qui engendrent une roche compacte. L'altération des feldspaths et la dissolution des carbonates créent des pores secondaires. La dernière phase de diagenèse est représentée par la cristallisation de la kaolinite et de l'illite.

The date for the formation of the Benton Uplift, Ouachita orogeny, is bracketed by Carboniferous synorogenic sediments deposited to the north and Late Pennsylvanian to Early Permian isotopic dates from the weakly metamorphosed rocks within the uplift. We address the largely unknown structural history between these two constraints by presenting an improved 3-dimensional kinematic model using better constrained retrodeformable sections. These new sections are based on all surface and subsurface data, new zircon fission track dates and thermal maturation data including new ‘crystallinity’ data to constrain the maximum burial depth. Concordant zircon fission track ages range from 307 ± 18.8 Ma to 333.4 ± 38.9 Ma or from the Late Devonian to Early Permian. Maximum ‘crystallinity’ of both illite and chlorite indicate these exposed rocks experienced a temperature of ~300°C across the eastern Benton Uplift. This temperature is consistent with reconstructed burial depths using cumulative stratigraphic thickness without having to call on structural thickening. Comparing coarse and fine clay fractions, computed temperature for the fine clay fraction is less by ~100°C than that of the coarse clay fraction. This difference is the same for all formations studied. This uniform difference in temperature may indicate cooling of the orogen as it deformed or more than one thermal event.

Abstract Cellulose micro- and nanofibrils are elongated, flexible nano-scale particles produced from natural fibres with intensive mechanical treatments, usually in the form of dilute aqueous suspensions. Due to the recalcitrant structure of the fibres, mechanical, chemical and enzymatic pre-treatments are often used to loosen the fibre wall structure so as to facilitate the mechanical liberation of micro- and nanofibrils and reduce the high amount of mechanical energy needed. However, it is still unclear how different chemistries affect the disintegration phenomena and how mechanical action starts to unravel the fibre structure, and thus how micro- and nanofibrillation could best benefit from the pre-treatments. In addition, the high water content used in the process increases the production and transportation costs of the material, so that the solids content should be increased. Reducing the water content before or after production would be challenging, however, due to changes in fibre properties during drying (hornification) and the tendency for the resulting nanofibrils to agglomerate. Also, the effect of high solids content and temperature on the reduction of fibres to nano- and microfibrils is still not well understood. The aims of this work were to follow the changes in fibre morphology after mechanical, chemical and thermal modification and address their effects on the disintegration phenomena of the fibres to microfibrils. Mechanical compression-shearing, two selective oxidations and thermal drying in combination with TEMPO oxidation were used to modify the fibre structure before mechanical disintegration in a high-shear homogenizer or ball mill. The results showed that sufficient swelling of the fibre cell walls was a prerequisite for successful microfibrillation. Swelling can be promoted by loosening the hydrogen bonding network with compression and shearing forces or by increasing the charge density. Different charge thresholds were observed for microfibrillation depending on the chemistry used. Extremely hornified fibres were also successfully microfibrillated with the aid of TEMPO oxidation. Different fibre disintegration mechanisms were seen depending on the modification type and disintegration conditions. In addition, micro- and nanofibrils and nanocrystals were successfully produced under high solids (≥ 50%) conditions. / Tiivistelmä Luonnonkuiduista saatavat selluloosamikro- ja -nanofibrillit ovat pitkiä ja joustavia nanokokoluokan partikkeleita, joita valmistetaan yleensä intensiivisillä mekaanisilla käsittelyillä vesiliuoksissa. Kuitujen lujan rakenteen vuoksi valmistuksessa käytetään usein mekaanisia, kemiallisia ja entsymaattisia esikäsittelyjä heikentämään kuituseinämän tiivistä rakennetta, mikä helpottaa mikro- ja nanofibrillien irtoamista kuituseinämästä, sekä alentaa valmistuksen mekaanisen energian tarvetta. On kuitenkin edelleen epäselvää, miten erilaiset kemialliset käsittelyt vaikuttavat kuitujen hajoamiseen, miten kuiturakenne alkaa purkautua mekaanisessa käsittelyssä ja miten esikäsittelyillä voitaisiin parhaiten edistää mikro- ja nanofibrilloitumista. Valmistuksessa käytettävä korkea vesipitoisuus lisää mikro- ja nanofibrillien valmistus- ja kuljetuskustannuksia. Vesipitoisuuden alentaminen valmistuksessa tai sen jälkeen on kuitenkin haastavaa, sillä kuituominaisuudet muuttuvat kuivatuksessa ja valmiit nanofibrillit kimppuuntuvat helposti. Korkean kuiva-ainepitoisuuden ja lämpötilan vaikutusta kuidun hajoamiseen mikro- ja nanofibrilleiksi ei myöskään ymmärretä vielä täysin. Työn tarkoituksena oli tutkia sellukuitujen rakenteen muutoksia mekaanisen, kemiallisen ja lämpömuokkauksen seurauksena, sekä tutkia niiden vaikutusta kuidun purkautumiseen mikrofibrilleiksi. Kuiturakennetta muokattiin puristus-hiertomenetelmällä, kahdella selektiivisellä hapetusmenetelmällä, sekä lämpökuivauksen ja nk. TEMPO-hapetuksen yhdistelmällä ennen kuitujen mekaanista hajottamista joko leikkaavassa homogenisaattorissa tai kuulamyllyssä. Tulosten perusteella riittävä kuituseinämän turvottaminen oli edellytys onnistuneelle mikrofibrilloinnille. Turpoamista saatiin edistettyä hajottamalla kuiduissa olevia vetysidosverkostoja puristus- ja leikkausvoimilla tai kasvattamalla anionisen varauksen määrää kuiduissa. Varauksen kynnysarvo mikrofibrilloitumiselle riippui käytetystä hapetusmenetelmästä. Myös kuivatuksessa erittäin sarveistuneet kuidut saatiin mikrofibrilloitua TEMPO-hapetuksen avulla. Tulosten perusteella kuiduilla on erilaisia hajoamismekanismeja, jotka riippuvat käytetystä muokkauksesta, sen intensiivisyydestä, sekä hajottamisolosuhteista. Työssä onnistuttiin myös valmistamaan mikro- ja nanofibrillejä, sekä nanokiteitä tavanomaista huomattavasti korkeammassa (≥50 %) kuiva-ainepitoisuudessa.

Células tronco hematopoéticas (CTH) de sangue de cordão umbilical (SCU) possuem grande potencial em terapia celular. Mesmo sendo bem caracterizadas quanto às suas propriedades funcionais e fenotípicas, a regulação da auto-renovação de CTH e os genes envolvidos são pouco conhecidos. Investigou-se através da curva de crescimento, ensaio clonogênico e citometria de fluxo, a expansão e diferenciação de CTH cultivadas sem e com suplementação dos mitógenos estradiol e LiCl. A expressão da subunidade da telomerase teve aumento significativo em todas as condições, bem como a expressão de Nanog e Oct4 relacionados a pluripotência e auto-renovação. Observou-se também a expressão de Nanog, Oct4, Sox2 e FoxD3 em células CD133, células CD3 de sangue periférico e células de colônias hematopoéticas. Concluiu-se que o meio sem suplementação já é suficiente na expansão de CTH, mantendo suas características, relacionadas à proliferação, auto-renovação e pluripotência celular. / Hematopoietic stem cells (HSC) from umbilical cord blood (UCB) have a great potencial for hematopoietic reconstitution. Although these stem cells have been well characterized by their functional and fenotipics properties, self-renewal regulation and genes involved are still unknown. Analyses of cell growth, clonogenic assay and flow cytometry revealed the expansion and differentiation of HSC grown in medium with or without suplementation of the mitogens estradiol and LiCl. Expression of the subunit of telomerase increased in all treatments. As well as the expression of Nanog and Oct4, related to plutipotency and self-renewal. Nanog, Oct4, Sox2 and FoxD3 expression was also high in CD133 cells, in CD3 cells from peripherical blood and in clonogenic assay derived cells. Conclusion: medium without the suplementation is sufficient for expansion of HSC, keeping their characteristcs, realted to proliferation, self-renewal and pluripotency.

Currently, there is very little research available on nonpoint source pollution from rural watersheds. Government regulatory agencies are desperate for information regarding the causes of nonpoint source pollution, which includes the relationship between suspended soil particles and dispersion. Since soil dispersion is dependent on clay mineralogy, knowing the clay mineralogy of the soil in an area can help predict sediment loads entering the surrounding surface waters. This information is necessary to protect the resource value of our rivers, lakes, and estuaries, as well as to protect recreational activities such as fishing or hunting; but most importantly, this information is necessary to ensure the safety of our drinking water supply. Clay mineralogy and its influence on dispersion, as well as dispersion and its relation to water quality are the focus of this study. Soil mineralogy affects water quality in several ways: soil mineralogy determines the dispersivity of the clay portion of the soil and dispersive clays are likely to end up as suspended sediment in surface waters; weathering reactions contribute elements to water as dissolved load, and the sorption properties of clay minerals contribute to soils' ability to filter and carry pollutants. Through the use of X-ray diffraction, dispersivity, atomic absorption spectrometry, cation exchange capacity, and petrographic microscopy, this study shows that the clay mineral fraction of a soil determines the dispersivity, and that dispersed clay minerals contribute excess nutrients and metals as nonpoint source pollutants to surface waters.