<p>The main project Dry preservation of source-separated organic household wastes involves a new technique for treatment of biowaste through drying. Investigations are going on to determine how the dried biowaste best can be used to close the natural circular flow of nutrients. The objective of this degree project is to determine if the dried biowaste can be used as a soil conditioner. By restoring the nutrients in the material to the ground, the natural circular flow is closed. A declaration of contents, including the nutrient levels, C/N ratio, pH and the electrical conductivity of the dried biowaste, was constructed and a germination test was done to make sure that the material did not inhibit sprouting. Further on a method was developed to study the decomposition process, and in particular the nitrogen mineralization of the dried biowaste. This method was then used practically.</p><p>The results of this degree project indicate that the decomposition capacity of the dried biowaste is very good. The germination test showed that the material in a diluted form (up to 50 % dried biowaste) did not inhibit sprouting. The examination of the nitrogen mineralization showed a fast liberalisation of nutrients available to plants, with only a shorter period of nitrogen immobilization. Together these results imply that the dried material could function well as a soil conditioner.</p> / <p>Projektet Torrkonservering av matavfall från hushåll innefattar en helt ny teknik för behandling av bioavfall genom torkning. Undersökningar pågår angående hur det torkade bioavfallet bäst kan användas för att sluta det naturliga kretsloppet. Examensarbetets huvudsyfte var, som ett led i dessa undersökningar, att utreda om det torkade bioavfallet kan användas som ett jordförbättringsmedel. Genom att tillföra bioavfallet till jord så återförs näringen i materialet till marken och kretsloppet sluts. En varudeklaration, med materialets näringshalter, C/N-kvot, pH och elektrisk konduktivitet, togs fram och ett groningstest utfördes för att kontrollera att bioavfallet inte var groningshämmande. Vidare utvecklades en metod för att studera det torkade bioavfallets nedbrytningsegenskaper i form av dess kvävemineralisering. Denna metod användes därefter praktiskt.</p><p>Resultatet av detta examensarbete tyder på att torkat bioavfall har mycket goda nedbrytningsegenskaper. Groningsförsöket visade att materialet i utspädd form (upp till 50 % torkat bioavfall) inte är groningshämmande, och mineraliseringsförsöket visade på en snabb frigörelse av växttillgängligt kväve, och en immobiliseringsperiod på ett par veckor. Tillsammans indikerar dessa resultat att det torkade materialet kan fungera väl som ett jordförbättringsmedel.</p>

Cette étude s’inscrit dans le cadre de l’amélioration des connaissances sur la dégradation photocatalytique des bioaérosols bactériens. La photocatalyse est une technique d’épuration basée sur l’excitation d’un semi-conducteur par un rayonnement le plus généralement ultraviolet. Cette technologie permet, en théorie, de minéraliser pas à pas les polluants. Or, si les conditions optimales ne sont pas réunies, la minéralisation incomplète peut conduire à des sous-produits de dégradation de toxicité potentiellement préoccupante.L’objectif de ces travaux a donc été d’apporter des éléments de compréhension quant aux mécanismes de dégradation photocatalytique d’un bioaérosol bactérien modèle d’E.coli, où de nombreux phénomènes sont couplés. Ainsi, pour distinguer les différents processus mis en jeu, deux approches expérimentales ont été menées. La première, nommée approche « batch », a permis d’isoler la réaction photocatalytique, à proprement parler, en étudiant les étapes d’inactivation, de libération de sous-produits et de minéralisation progressive. La seconde, appelée approche « dynamique » a permis quant à elle la mise en place d’un dispositif expérimental adapté à la dégradation photocatalytique d’un bioaérosol d’E.coli. Les capacités de la photocatalyse à inactiver et minéraliser des espèces bactériennes ont pu être démontrées. Les paramètres clés d’une dégradation efficace ont été mis en évidence et ont permis de décrire les verrous indispensables à une industrialisation sûre du procédé / This study comes within the scope of improving knowledge concerning the photocatalytic degradation of bacterial bioaerosol. Photocatalysis is a purification technology generally based on the excitation of a semiconductor by an ultraviolet radiation. This technology can, in theoretical ways, mineralize pollutants step by step. However, if optimal conditions are not gathered, this mineralization is incomplete and can lead to the formation of potentially toxic by-products. The aim of this work was therefore a better understanding of the mechanisms of photocatalytic degradation of a bacterial bioaerosol of E.coli, where numerous phenomenon are linked. Thus, to distinguish the different processes, two experimental approaches were used. The first one, called “batch approach”, allowed to consider the photocatalytic reaction itself, by studying the steps of inactivation, by-products formation and progressive mineralization. The second one, named “dynamic approach”, consisted to design an experimental setup suited to the photocatalytic degradation of a bioaerosol of E.coli. The abilities of photocatalysis to inactivate and mineralize bacteria could be demonstrated. The key parameters of an efficient degradation were highlighted and allowed to underline the problems to solve before having a safe industrialization of the photocatalysis

PHEX est une protéine importante dans le processus de minéralisation osseuse. Des mutations ou la délétion d’une partie de ce gène causent l’hypophosphatémie liée au chromosome X (XLH). Cette maladie est caractérisée par une hypophosphatémie, accompagnée de défauts de minéralisation, de rachitisme et de lésions ostéomalaciques. Avec l’hypophosphatémie, les taux circulants de vitamine D devraient être augmentés, ce qui n’est pas le cas d’où une régulation anormale de la production de vitamine D a lieu. Cependant, malgré le fait que cette protéine soit une peptidase, aucun substrat physiologique n’a encore été répertorié pour PHEX. PHEX est une protéine membranaire de type II de la famille M13 des métalloendopeptidases à zinc possédant un court domaine N-terminal cytosolique, un segment transmembrannaire d’environ 20 acides aminés et une large portion C-terminale extracellulaire où se trouve le site actif de l’enzyme. PHEX est exprimée de façon majoritaire dans les os et dans les dents et elle apparaît à l’initiation de la minéralisation. Les patients souffrant de XLH et la souris Hyp, qui est un modèle animal de la maladie humaine, montrent des quantités importantes de la protéine FGF23. De plus, FGF23 est impliqué dans une autre maladie reliée au métabolisme du phosphate, l’hypophosphatémie rachitique autosomale dominante (ADHR) où des mutations de FGF23 causent sensiblement les mêmes symptômes que XLH. FGF23 est produit principalement par les ostéoblastes et les ostéocytes. FGF23 cause une hypophosphatémie par la diminution de l’expression du cotransporteur NaPi de type II, responsable de la réabsorption du phosphate rénal. L’hypothèse proposée dans la littérature serait que PHEX activerait ou inactiverait des peptides importants pour la minéralisation osseuse. Plus spécifiquement, l’activation ou l’inactivation de ces peptides aurait pour rôle de réguler les quantités de FGF23. Selon l’hypothèse mentionnée précédemment, la régulation de PHEX pourrait donc avoir un effet sur la minéralisation. Une quantité croissante de données sur la régulation de PHEX sont maintenant disponibles. Par exemple, la vitamine D diminue l’expression de PHEX tandis que les glucocorticoïdes et l’hormone de croissance augmentent son expression. Dans une première étude, nous avons voulu déterminer si un peptide relié à la minéralisation osseuse, le PTHrP1-34, pouvait réguler l’expression de PHEX. Nous avons déterminé que le PTHrP1-34 peut réguler de façon négative l’expression de PHEX dans les cellules UMR-106, une lignée cellulaire ostéoblastique. Cette régulation passe par la voie de l’AMPc/protéine kinase A. De plus, cette diminution d’expression est également observée au jour 7 dans des cultures primaires d’ostéoblastes de rat en minéralisation. Par la suite, nous avons étudié un mutant de PHEX, le mutant E4Q retrouvé chez un patient souffrant de XLH, où la mutation se retrouve dans le domaine cytosolique de PHEX. Cette mutation n’interfère pas avec le site catalytique de l’enzyme puisque ce mutant de PHEX peut tout aussi bien cliver un substrat synthétique que la protéine sauvage. Il a été déterminé que cette mutation annule un motif di-acide. Nous avons démontré que ce motif di-acide est responsable de la liaison de PHEX à COPII, responsable de la formation de vésicules de sécrétion. De plus, il semblerait que ce motif soit important, probablement par son interaction avec COPII, à l’incorporation de PHEX dans des vésicules de calcification, lesdites vésicules étant importantes dans le processus de minéralisation. Finalement, des essais de compétitions ont démontré que la minéralisation pouvait être perturbée lorsque l’on surexprimait la queue cytosolique sauvage de PHEX, contrairement à la queue mutée. Ceci suggère possiblement que l’interaction avec COPII menant à l’incorporation de PHEX dans les vésicules de calcification ou d’autres protéines comprenant de tels motifs pourrait être importante pour la minéralisation. Finalement, la dernière étude porte sur la protéine FGF23. Nous avons démontré, par la surexpression de FGF23 dans la lignée MC3T3 d’ostéoblastes de souris, que cette surexpression a un effet sur la sénescence de ces cellules. En effet, des essais de sénescence ont montré l’augmentation de celle-ci lorsque FGF23 est surexprimé. Par contre, la prolifération n’est pas altérée. De plus, il semblerait que la différenciation soit plus rapide, tel qu’observé par une minéralisation survenant plus tôt, mais n’étant pas plus importante. Bref, la surexpression de FGF23 semblerait faire en sorte que les ostéoblastes se différencient plus rapidement et passent donc à un état de sénescence prématuré comparativement aux cellules sauvages. Ceci est en accord avec la littérature où KLOTHO, un cofacteur de FGF23 permettant sa liaison avec une plus grande affinité sur son récepteur, lorsqu’inactivé démontre un phénotype similaire au vieillissement incluant un phénotype de sénescence. / PHEX is an important protein in the process of osseous mineralisation. Mutations or deletions of a part of the PHEX gene cause X-linked hypophosphatemia (XLH). This disease is characterized by hypophosphatemia, accompanied by defects of bone mineralisation, rickets and osteomalacia. With the hypophosphatemia, the circulating levels of vitamin D should be increased, which is not the case where an abnormal regulation of the production of vitamin D takes place. However, in spite of the fact that this protein is a peptidase, no physiological substrate has been identified. PHEX is a membrane type II integral protein member of the M13 family of zinc metalloendopeptidasee. These proteins have a short N-terminal cytosolic domain, a transmembrane domain of approximately 20 amino acids and a large extracellular C-terminal portion where the active site of the enzyme is located. PHEX is expressed predominantly in bones and teeth in osteoblasts and odontoblasts, respectively. PHEX is expressed at initiation of mineralization. Patients suffering from XLH and the Hyp mouse, which has been used widely as an animal model of the human disease, show large quantities of the FGF23 protein. Moreover, FGF23 is implicated in another disease connected to phosphate metabolism, the autosomal dominant hypophosphatemic rickets (ADHR) where activating mutations in FGF23 cause roughly the same symptoms as XLH. FGF23 is produced mainly by osteoblasts and osteocytes. FGF23 causes hypophosphatemia by decreasing the expression of the type II sodium phosphate cotransportor, partly responsible for renal phosphate reabsorption. The hypothesis suggested in the literature would be that PHEX would activate or inactivate important peptides for osseous mineralisation. More specifically, the activation or the inactivation of these peptides would have a role in the control of FGF23 expression. According to the assumption mentioned previously, the regulation of PHEX could thus have an effect on mineralization. An increasing quantity of data on the regulation of PHEX is now available. For example, vitamin D decreases the expression of PHEX while glucocorticoids and growth hormone increase its expression. In a first study, we examined the possibility that a peptide connected to osseous mineralization could control the expression of PHEX. We determined that PTHrP1-34 can control in a negative way the expression of PHEX in UMR-106 cells, a cell line of osteoblastic origin. This regulation involves the cAMP/protein kinase A pathway. Moreover, this decrease in PHEX expression is also observed at day 7 in primary cultures of mineralizing rat osteoblasts. Next, we looked more closely at PHEX cellular localization. We used a mutant of PHEX, mutant E4Q identified in an XLH patient, where the mutated amino acid is found in the cytosolic domain of PHEX. This change does not interfere with the catalytic site of the enzyme since this PHEX mutant can still cleave a synthetic substrate as well as wildtype protein. This mutation disrupts a di-acidic motif present in the cytosolic domain of PHEX. We showed that this di-acidic motif is reponsible for the interaction of PHEX with COPII, a protein complex involved in the formation of secretion vesicles. Moreover, it would seem that this di-acidic motif is important, probably by its interaction with COPII, to the incorporation of PHEX in matrix vesicles, which are important in the mineralization process. Finally, competition assays showed that mineralization could be disturbed when the wildtype PHEX cytosolic tail is overexpressed, as opposed with the mutated cytosolic tail. This suggests that the interaction with COPII and the subsequent incorporation of PHEX in matrix vesicles or other proteins that possesses this motif could be important for mineralization. Finally, the last study examined the role of FGF23 on mineralization. We showed, by the overexpression of FGF23 in the mouse MC3T3 osteoblast cell line, that FGF23 can cause senescence of these cells. On the other hand, proliferation is not affected. Moreover, differentiation seems to occur at a faster rate, as indicated by earlier mineralization. Overexpression of FGF23 would accelerate differentiation and induce senescence. This is in agreement with the literature where KLOTHO, a FGF23 cofactor that increase the affinity of FGF23 for its receptor, when inactivated, shows a similar phenotype that includes senescence and aging.

Saltwater intrusion due to global change is expected to have a detrimental effect on the biogeochemistry of tidal freshwater wetlands. Of particular concern is that fact that salinization can alter the role of these ecosystems in the global carbon cycling by causing shifts in microbial metabolism that alter greenhouse gas emissions and increase carbon mineralization rates. However, our understanding of how wetland microbial community dynamics will respond to saltwater intrusion is limited. To address this knowledge gap and increase our understanding of how microbial communities in tidal freshwater wetlands change over time (1, 3, 12, and 49 weeks) under elevated salinity conditions, an in situ soil transplant was conducted. Throughout the 49 weeks of saltwater exposure, salinity had no effect on soil quality (organic matter content and C:N ratio). In contrast, the concentration of porewater ion species (SO4-2, NO3-, and NH4+) considerably increased. The activity of hydrolytic enzymes, (ß-1,4-glucosidase and 1,4-ß-cellobiohydrolase) gradually decreased with prolonged exposure to saline conditions; by the final sampling event (49 weeks), activity was reduced by ~70% in comparison to the freshwater controls. Short term exposure to salinity (3 and 12 weeks) had a greater effect on phenol oxidase, decreasing activity by 10-20%. Saltwater exposure had an immediate (1 week) effect on potential rates of carbon mineralization; overall, carbon dioxide production doubled and methane production decreased by ~20-fold. These changes in gas production were correlated to increased salinity and to changes in the abundance of methanogens and sulfate reducing bacteria, suggesting a shift in the terminal step in organic matter degradation from methanogenesis to sulfate reduction. Principal component analysis revealed distinct changes in soil environmental conditions and carbon metabolism within weeks, but the response of the microbial community was slower (months to a year). Taken together, results from this study indicate that the response of tidal freshwater wetlands to salinization is driven by complex interactions of microbial related processes and environmental changes that are dependent on the duration of exposure. Assessing the impact of environmental perturbation on ecosystem function may be better achieved by complementary analysis of both microbial community structure and function.

Master of Science / Department of Geology / Saugata Datta / In response to increasing concerns over release of anthropogenic greenhouse gases the Arbuckle saline aquifer in south-central Kansas has been proposed as a potential site for geologic storage for CO2. Two wells (KGS 1-32 and 1-28) have been drilled to provide data for site specific determination of the storage potential of the Arbuckle. Cores from specific depths within Arbuckle (4164`-5130`) were utilized for study and flow-through experiments. Examination of formation rocks by thin section studies, SEM, XRD and CT scans was carried out to characterize the mineralogy of the core. Dominant mineralogy throughout the formation is dolomite with large chert nodules and occasional zones with pyrite and argillaceous minerals. Carbonate-silica contacts contain extensive heterogeneity with sulfide minerals and argillaceous material in between. Extensive vugs and microfractures are common. This study focuses on three zones of interest: the Mississippian pay zone (3670`-3700`), a potential baffle in Arbuckle (4400`-4550`) and the proposed CO2 injection zone (4900`-5050`). Drill stem tests and swabbed brine samples collected from 13 depths throughout the aquifer reveal a saline brine (~50,000-190,000 TDS) dominated by Na+, Ca2+ and Cl-. Elemental ratios of major cations with Cl- demonstrate a typical saline aquifer system. Cl/Br ratios reveal mixing between primary and secondary brines within the aquifer. Ca/Cl and Mg/Cl ratios suggest effect of dolomitization within the brines. δ18O and δ2H isotopes and Li/Cl ratios in the brine suggest the separation of upper and lower Arbuckle by a baffle zone. Swabbed waters provide Fe speciation data and reveal the importance of it in the system. Laboratory experiments carried out at 40°C and 2100 psi using formation core plug and collected brine identify reaction pathways to be anticipated when supercritical CO2 is injected. Results showed fluctuating chemistries of elements with Ca2+, Mg2+, Na+ and Cl- increasing during the first 15 hours, while Fe, S, and SO42- decrease. For the next 15 hours a reverse trend of the same elements were observed. Alkalinity and pH show inverse relationship throughout the experiment. We conclude that dominant reactions will occur between brine, CO2 and dolomite, calcite, chert, pyrite and argillaceous minerals. There is no perceived threat to freshwater resources in Kansas due to CO2 injection.

Doctor of Philosophy / Department of Agronomy / Charles W. Rice / Increasing atmospheric CO2 concentrations and other greenhouse gases have been linked to global climate change. Soil organic C (SOC) sequestration in both agricultural and native ecosystems is a plausible option to mitigate increasing atmospheric CO2 in the short term. Laboratory and field studies were conducted to (1) understand the influence of soil water content on the temperature response of SOC mineralization (2) investigate burn and nutrient amendment effects on biogeochemical properties of tallgrass prairie and (3) assess perennial and annual plant management practices on biophysical controls on SOC dynamics. The laboratory study was conducted using soils collected from an agricultural field, currently planted to corn (C4 crop), but previously planted to small grain (C3) crops. The changes in cultivated crops resulted in a δ¹³C isotopic signature that was useful in distinguishing older from younger soil derived CO2-C during SOC mineralization. Soils were incubated at 15, 25 and 35 oC, under soil water potentials of -1, -0.03 and -0.01 MPa. Soil water content influenced the effect of temperature on SOC mineralization. The impact of soil water on temperature effect on SOC mineralization was greater under wetter soil conditions. Both young and older SOC were temperature sensitive, but SOC loss depended on the magnitude of temperature change, soil water content and experiment duration. Microbial biomass was reduced with increasing soil water content. The first field experiment investigated burn and nutrient amendment effects on soil OC in a tallgrass prairie ecosystem. The main plots were burned (B) and unburned (UB) tallgrass prairie and split plots were nutrient amendments (N, P or N+P including controls). Vegetation was significantly altered by burning and nutrient amendment. Treatment effects on either TN or SOC were depth-specific with no impact at the cumulative 0-30 cm depth. The P amendment increased microbial biomass at 0-5 cm which was higher in unburned than burned. However, at 5-15 cm depth N amendment increased microbial biomass which was higher in burned than unburned. In conclusion, soil OC in both burned and unburned tallgrass prairie may have a similar trajectory however; the belowground dynamics of the burned and unburned tallgrass prairie are apparently different. Another field experiment assessed SOC dynamics under perennial and annual plant management practices. The main plots were grain sorghum (Sorghum bicolor) planted in no-tillage (NT) or continuous tillage (CT), and replanted native prairie grass, (Andropogon gerardii) (RP). The spit plots were phosphorus (+P) and control without P (-P). The P amendment was used to repress arbuscular mycorrhizal fungi (AMF), known to influence soil aggregation. The macroaggregate >250 µm, SOC and TN were higher in RP and NT than CT. The relative abundances of AMF and saprophytic fungi were greater with less soil disturbance in RP and NT than in CT. Therefore, less soil disturbance in RP and NT increased AMF and fungal biomasses. The higher relative abundances of AMF and fungi with less soil disturbance increased macroaggregate formation in RP and NT, which resulted in higher SOC sequestration in RP and NT than CT.

IDans la région de Dabakala située au Nord-Est de la Côte d’Ivoire, la croûte birimienne de l’Afrique de l’Ouest comporte trois séries volcano-Sédimentaires, toutes orientées NNE-SSW: celle de la Haute Comoé à l’est, celles du Haut-N’Zi et de Fettêkro à l’ouest. Elles constituent l’encaissant d’importants massifs granitiques datés à 2,1 Ga, l'ensemble formant une ride granitique bordée par deux sillons volcano-Sédimentaires.Les données pétrographiques et géochimiques montrent que les volcanites présentent des variations de composition continues de basalte à rhyolite. Les métabasites, subalcalins à alcalins montrent une source de type lherzolite à spinelle, avec une possible contamination crustale. Leur environnement de mise en place serait un contexte de subduction. Les andésites montrent une affinité avec les arcs insulaires continentaux matures, suggérant un modèle de subduction avec délamination crustale. Les volcanites acides, également mises en place dans un contexte d’arc volcanique, terminent la lignée calco-Alcaline.Les plutonites de la région de Dabakala, comprenant des massifs de pegmatite, granite, granodiorite, diorite, tonalite et trondhjémite, sont liées à des arcs volcaniques et caractérisent un magmatisme calco-Alcalin de marge active. Les métasédiments se reportent quant à eux dans le champ des arcs insulaires continentaux.Au plan structural, la région de Dabakala présente des directions de fractures majeures orientées N-S à NNE-SSW senestres pour la plupart (les plus anciennes), N90° à N100° dextres (les plus récentes), NW-SE dextres ou senestres. Une structure significative, de direction N075° à N080° est identifiée pour la première fois: la faille de Sarala (FSr). La carte structurale du prospect aurifère de Bobosso indique globalement un fort développement des linéaments NNE-SSW recoupés par des linéaments NW-SE. Les premiers dessinent une mégastructure de premier ordre dénommée Zone Tectonique de Bobosso (ZTB), abritant plusieurs structures secondaires avec des lentilles minéralisées.Concernant la minéralisation aurifère, le prospect de Bobosso dans la série de la Haute-Comoé présente une déformation polyphasée avec une déformation cassante à l’origine de la formation de plusieurs générations de veines de quartz. La minéralisation aurifère présente un contrôle structural principalement marqué par les filons de quartz liés à la mise en place d’intrusions dans les basaltes et les andésites. Il existe deux types de minéralisations: une disséminée et l’autre filonienne. Cette distribution bimodale de l’or a été également mise en évidence dans les gisements de la ceinture Ashanti au Ghana et dans plusieurs gisements aurifères mondialement connus.La minéralisation disséminée serait syngénétique, d'après l’existence de teneurs élevées dans les sections de sondages sans aucun filon de quartz. La minéralisation filonienne est évidemment épigénétique. Les teneurs les plus élevées ont été obtenues dans les zones de sondages montrant la présence de lentilles, veines et filons de quartz, calcite ± tourmaline ± sulfures. La paragenèse métallifère est essentiellement constituée de pyrite, mais également de pyrrhotite, chalcopyrite et d’arsénopyrite, avec présence de magnétite et d’hématite. L'or n’est jamais visible à l’oeil nu, même dans les sections de forage présentant les plus fortes teneurs.Nous pouvons retenir une principale phase de minéralisation dans le prospect aurifère. Elle est de type hydrothermal et liée à la mise en place de granitoïdes dans les métasédiments et les volcanites lors de la fermeture des bassins à la fin de l’orogenèse éburnéenne. La minéralisation filonienne montre de plus fortes teneurs en Or. / In Dabakala region located in the northeastern part of Côte d'Ivoire, the birimian crust of West Africa displays three volcano-Sedimentary series: the Upper Comoé serie to the east, and the Upper N'Zi and Fettêkro series to the west. These three volcano-Sedimentary series are NNE-SSW oriented and enclose an important granitic mass dated to 2.1 Ga; thus constituting a granitic ridge bordered by two volcano-Sedimentary trenches.Petrographic and geochemical data show that these pyroclastic rocks have basalts, andesites, andesite basalts, dacites, rhyolites and rhyodacites compositions. Metabasites are generally subalkaline to peralkaline and show their source composition between those of N- MORB and E- MORB. Fettêkro serie basalts, with La / Yb values between 1.43 to 1.83 and La values between 2.21 to 5.6, are close to average of Nauru basalts and belts’ mafic. Their magmatic source would be spinel lherzolite type, with probably possible crustal contamination in an environment of implementing intra -Oceanic environment with building oceanic plateaus. Andesites show an affinity to continental and mature island arcs basalts, corresponding to a subduction model with crustal delamination. Acid volcanics are implemented in a volcanic arcs context and follow a calc-Alkaline suite.The plutonic rocks of the Dabakala region are composed to pegmatite, alkali and natural granite, granodiorite, diorite and gabbro. These rocks correspond to syn-Collisional volcanic arc plutonites, and are probably related to a calc-Alkaline magmatism of active margins. Metasediments generally defer in the field of continental island arcs.Structurally, the Dabakala region has major fractures directions oriented NS to NNE-SSW sinistral for most (older), N90° to N100° dextral (latest), NW-SE to NNW-SSE dextral or sinistral. A significant structure, oriented N075° to N080° is identified for the first time: the Sarala fault (FSr). The structural map of the Bobosso gold prospect generally indicates a strong development of NNE-SSW lineaments cut by NW-SE lineaments. The first ones draw a first order megastructure called Bobosso Tectonic Zone (ZTB), containing multiple secondary structures or mineralized lenses.Concerning gold mineralization, the Bobosso prospect (Upper-Comoé serie) has a polyphase deformation with brittle deformation as manifested in several ways. The latter is the cause of the formation of several generations of quartz veins. Gold mineralization presents mainly a structural control by quartz veins, related to the development of intrusions in basalts and andesites.. Two types of mineralization may be mentioned: disseminated and vein. This bimodal distribution of gold has also been highlighted in the Ashanti belt deposits in Ghana and several gold deposits known worldwide.Disseminated mineralization is syngenetic and relies on the existence of high grade in sections of surveys without quartz vein. The vein mineralization is evidently epigenetic. The highest grades were obtained in sections showing the presence of lenses, veins and quartz veins, tourmaline ± calcite ± sulfides. The metalliferous paragenesis consists essentially of pyrite, but pyrrhotite, chalcopyrite and arsenopyrite with presence of magnetite and hematite. Gold is not visible, even in the drill sections with the highest grades.We retain two main phases of mineralization in the Bobosso gold prospect: 1) a first phase (SEDEX type) occurred while opening rear arc basins. It occurs mainly in the metasediments and 2) a second phase (hydrothermal) related to the implementation of various granitoids in the metasediments and volcanics when closing pools at the end of the eburnean orogeny. Vein mineralization shows higher grades of gold.

Um dos maiores desafios da ortopedia é recuperar o tecido ósseo que tenha sido perdido por motivo de doença ou acidente. Na busca de substitutos para os enxertos, tem-se utilizado comumente biomateriais, para recuperação desse tecido. A quitosana é um polímero biocompatível, biodegradável e juntamente com a gelatina, que é produto da desnaturação do colágeno, possuem uso potencial no área de regeneração de tecidos ósseos. O objetivo deste trabalho é a preparação, caracterização de hidrogéis de quitosana:gelatina mineralizados, em diferentes proporções (1:0,5; 1:1 e 1:2) e estudar a liberação controlada de gentamicina utilizando como suporte o hidrogel mineralizado. A quitosana foi obtida a partir da desacetilação parcial da quitina oriunda de gládios de lula e a gelatina utilizada é a comercial Sigma®. Os hidrogéis foram mineralizados pelo método de imersão alternada em soluções de CaCl2 0,2 mol L-1 pH=7,4 e de Na2HPO4 0,12 mol L-1 pH=9,0. A mineralização foi caracterizada por espectroscopia na região do infravermelho (FTIR), análise termogravimétrica (TG), microscopia eletrônica de varredura (MEV), dispersão de raios-X (EDS), difração de raios-X (DRX) e cinética de absorção em PBS. Nas análises de TG e MEV pode-se observar a ocorrência de mineralização homogênea no hidrogel, aproximadamente 60% (m/m) em todas as proporções. Nos espectros de FTIR, EDS e DRX, observou-se que o sal de fosfato de cálcio formado durante o processo de mineralização alternada corresponde à hidroxiapatita. Quanto ao estudo de absorção em PBS, os hidrogéis mineralizados apresentam menor intumescimento que os não-mineralizados. Estudou-se o comportamento da liberação in vitro (em PBS, pH 7,4) de gentamicina no hidrogel mineralizado de quitosana/gelatina (1:1) quando se altera a temperatura da liberação (25°C e 37°C). A gentamicina foi incorporada ao hidrogel mineralizado através da imersão em uma solução com concentração de 30 mg ml-1 de gentamicina. O estudo de liberação foi realizado em duas temperaturas 25°C e 37°C. A quantidade de fármaco liberado após 24 horas não é afetada pela alteração na temperatura, mas a velocidade da liberação nas duas primeiras horas é maior a 37°C do que a 25°C. O mecanismo de liberação da gentamicina foi ajustado para o modelo Korsmeyer-Peppas sugerindo que segue a difusão Fickiana. / The replacement of bone tissue lost due to illness or accident is a great challenge in orthopedic area. Biomaterials have been commonly used to prepare new materials for substitution of lost tissue. Chitosan is a biocompatible and biodegradable polymer and its association with gelatin has potential application in bone tissue regeneration. The objective of this study is to describe the preparation and characterization of mineralized hydrogels of chitosan/gelatin prepared with different ratios (1:0.5, 1:1 and 1:2) and the controlled release of gentamicin using the mineralized hydrogel as a support. Chitosan was obtained from the partial deacetylation of squid pens and gelatin was commercial (Sigma ®). The mineralization process was carried out by the alternate soaking method. Hydrogels were soaked in 0.2 mol L-1 CaCl2 buffered with 0.05 mol L-1 Tris buffer (pH 7.4) at 25°C for 30 min, taken out of the Ca2+ solution, rinsed with deionized water and then soaked in 0.12 mol L-1 Na2HPO4 solution buffered with 0.05 mol L-1 Tris buffer (pH 9.0) for 30 min, taken out of the PO43- solution and rinsed with deionized water. The alternate soaking cycle was repeated 6 times to obtain the mineralized matrices which were then rinsed with water, frozen and lyophilized. Mineralized hydrogels were characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TG), scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray diffraction (XRD) and kinetic absorption in PBS. SEM results showed an homogeneous mineralization, and for all hydrogels a quantity of approximately 60% (w/w) of mineralization was determined by TG. FTIR, EDS and XRD indicated that phosphate calcium deposited during mineralization process was hydroxyapatite. Mineralized hydrogels had lower swelling values in comparison with non-mineralized, as observed by absorption in PBS. Release of gentamicin in mineralized hydrogel was performed at 25°C and 37°C. Gentamicin was incorporated in the mineralized hydrogel by immersion in a gentamicin solution with a concentration of 30 mg ml-1. The change in release temperature showed that the quantity of drug delivery was not affected after 24 hours. However, the release rate in the first hour is higher at 37°C. The release mechanism of gentamicin was adjusted to the Korsmeyer-Peppas model suggesting that drug release is mostly controlled by a diffusion process.

Osteoporose é a doença osteometabólica mais comum na população idosa. É definida como redução difusa da qualidade óssea que surge por um desbalanço entre a reabsorção e a formação óssea. Vários fatores etiológicos acontecem juntos levando à redução das proteínas ósseas, entre eles: deficiência hormonal, senilidade, subnutrição e imobilização. Um fator etiológico que, além dos processos de mutação, leva a alteração da estrutura do colágeno no processo de envelhecimento é o ageing, que se caracterizado por mudanças estruturais na matriz extracelular e virtualmente atinge todos os tecidos e sistemas orgânicos. Mudanças nas ligações cruzadas têm sido considerada como o papel principal do ageing e essas ocorrem através de 2 principais maneiras: a primeira é um processo enzimático pela ação da lisil oxidase e a segunda é um processo não-enzimático e recebe o nome de glicação. Essa última envolve reação da glicose com arginina (Arg) e lisina (Lys) sendo a principal causa de disfunção dos tecidos colágeno na idade avançada. No ageing há hidroxilação da lisina (Lys) levando modificação nas ligações cruzadas, o que gera uma estrutura de colágeno alterada. Além disso, a alteração em especial da arginina (Arg) afeta a crucial interação célula-matriz envolvendo motifs como o RGD (Arg-Gly-Asp), o que altera a mineralização e remodelagem óssea. Essas modificações envolvendo o intervalo 70-110 do período D do colágeno tipo I, que corresponde a interface overlap:gap tem uma séria repercussão, pois segundo o modelo de mineralização, qualquer variação de carga nesse local afeta a interação com a fosfoforina, uma proteína ácida que parece ser o gatilho para o processo de mineralização da dentina, e que também, de alguma forma, deve ocorrer no tecido ósseo. Assim, em um colágeno bioquimicamente modificado pelas reações do ageing leva, entre outras coisas, a uma alteração na mineralização, e essa alteração seria mais um fator a ser considerado no estudo da osteoporose. / Osteoporosis is the most commom osteometabolic disease in the elderly. It´s definied like difuse reduction of bone density that arouses from a delicate debalance between bone reabsorption and formation. Several etiologic factors happens together and they result in the reduction of bone proteins, like hormonal deficiency, senility, bad nutrition and imobilization. Another etiologic factor that causes the collagen struture modification in old age it\'s ageing, characterized for structure modification on extracelular matrix and virtually affect all tissue and organic system. Modification on cross-link have been considered like main reason of ageing and these modifications occur through two main ways: the first one is an enzimatic process for the lysil oxidase action and the second is a non-enzimatic process denominated glycation. The last process involve the glucose reaction with arginine (Arg) and lysine (Lys) being the main cause of the collagen tissue disfunction in advanced age. In ageing process there is a lysine (Lys) hidroxilation modification the cross-link what results a fragilized collagen structure. Besides, the special modification of arginine (Arg) affects the crucial interaction of the cell matrix involving motifs like RGD (Arg-Gly-Asp), around the interval 70-110 of period collagen type I, that corresponds to the interface overlap:gap has a serious repercussion, because according to the mineralization standard, which charge alteration in this place affects the interaction with phosphoforin an acid protein that seems to be the responsible of mineralization process. In this manners, in a biochemically modified collagen causes, among other things, to a mineralization alteration, and it has its consequences on osteoporosis.

Durante a safra agrícola ocorrem aplicações simultâneas ou aplicações de um defensivo agrícola em seguida de outro. Esta prática gera a combinação de resíduos no solo que pode levar a mudanças no destino final destes compostos. Com o objetivo de investigar se a aplicação em mistura influencia no comportamento no solo de diuron, hexazinone e sulfometuron-methyl foram avaliadas a sorção, dessorção, biodegradação, lixiviação e efeito sobre microrganismos dos solos, após aplicação em mistura e isolada destes herbicidas, em diferentes solos. Nos estudos de lixiviação, sorção e biodegradação foram preparadas soluções com herbicidas radiomarcados e não radiomarcados. Nos tratamentos em mistura apenas o herbicida sendo avaliado era radiomarcado e os outros eram padrões analíticos. A avaliação do efeito sobre microrganismos foi realizada após aplicação dos herbicidas e de glicose radiomarcada. O delineamento utilizado foi o inteiramente casualizado. A mineralização e a porcentagem detectada nos lixiviados do solo arenoso, foram maiores quando hexazinone foi aplicado em mistura. A sorção foi menor quando hexazinone estava em mistura com diuron, em um dos cinco solos avaliados. A mineralização e sorção de diuron nos solos não foram influenciadas pela presença de hexazinone e sulfometuron-methyl. No caso de sulfometuron-methyl, a aplicação em mistura aumentou a mineralização do herbicida, contudo, não afetou a lixiviação tampouco a sorção do herbicida. Maior evolução de 14CO2 a partir da glicose foi observada nos tratamentos com sulfometuron-methyl, diuron e da mistura dos três herbicidas em solo arenoso, contudo não foi observado aumento dos efeitos dos herbicidas quando em mistura sobre atividade biológica do solo. / Herbicides can either be applied alone or simultaneously during the entire crop cultivation. This practice could potentially promote changes in herbicide behavior in the soil. Thus, the aim of this study was to understand the effect of diuron, hexazinone, and sulfometuron-methyl and its mixtures when applied on the soil. Herbicide sorption, desorption, biodegradation, leaching and its effect on the soil microorganism in contrasting soils textures were evaluated. Radiolabeled and an analytical standard herbicide were used to understand leaching, biodegradation and sorption. Microorganism evaluation was done by adding 14C-glucose. Highest mineralization percentage was observed in hexazinone mixed with diuron and sulfometuron-methyl leachates. The application in mixture did not affect the mineralization or sorption of diuron. In the case of sulfometuron-methyl, the application with diuron and hexazinone increased the mineralization of the herbicide, however it did not affect its leaching or sorption. A greater evolution of 14CO2 was observed in the treatments with sulfometuron-methyl, diuron and the mixture of the three herbicides in sand soil. Nevertheless, the application in mixture did not increase the effects of the herbicides in the soil biological activity.