Le Vanadium produit dans le monde est issus à près de 90% de complexes ignés comme celui du Bushveld en Afrique du Sud. Le Complexe de la Rivière Bell est localisé dans le camp minier de Matagami, au nord de la province d'Abitibi. C'est une intrusion litée de 750km2, d'âge 2725Ma qui présente un potentiel en vanadium, fer et titane. La partie ouest du complexe, entourée de gisements de sulfures massifs volcanogènes, présente une base de gabbros, une zone supérieure litée de gabbronorites contenant des lits d'oxydes à Fe-Ti-V, surmontée par une zone de granophyres. La zone d'oxydes, hôte des minéralisations en vanadium fut jusqu'à présent peu étudiée. La zone litée est marquée par un métamorphisme rétrograde au faciès amphibolite à schistes verts. Elle comprend des lits d'oxydes massifs et semi-massifs globalement orientés Est-Ouest, à pendage subvertical et à polarité vers le Nord. Elle contient également des séquences de gabbronorites mélanocrates à leucocrates, à oxydes disséminés. Les zones d'oxydes ont une épaisseur jusqu'à 200m avec des lits centimétriques à décimétriques, dont les teneurs moyennes de 27,3% Fe, 39,04% Fe2O3, 6,55% TiO2 et 0,42% V2O5. On observe plusieurs séquences magmatiques primaires, directement liées au processus de cristallisation fractionnée. Une phase tardimagmatique de bréchification, donnant des brèches à ciment de gabbronorites pegmatitiques, est présente au sommet de la zone litée. Les oxydes présents dans la zone litée sont l'ilménite et la titanomagnétite. La titanomagnétite présente des exsolutions d'ilménite en treillis associées à de l'ulvöspinelle et de l'hercynite. Le vanadium est inclus dans la structure cristalline de la magnétite où les ions V3+ vont remplacer les ions Fe3+. Les observations texturales et les analyses géochimiques montrent que la zone supérieure litée du Complexe de la Rivière Bell est vraisemblablement issus d'une injection de magma mafique associée à un mélange avec un liquide résiduel enrichi en V-Fe-Ti. Ce mélange est possiblement issu de la zone de gabbros massifs sous-jacente. Plusieurs particularités distinguent le Complexe de la Rivière Bell d'autres complexes connus dans le monde comme celui du Bushveld, impliquant une mise en place avec un fort contraste thermique, vraisemblablement à faible profondeur. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : gisement de vanadium, complexe mafique, titanomagnétite, litage magmatique, cristallisation fractionnée.

The purpose of this project was to determine the vanadium bearing ore minerals present at the Green Giant vanadium-graphite deposit in the S.W. of Madagascar owned by Toronto based Energizer Resources Inc. The rocks are mainly quartzofeldspathic gneiss, with alternating bands of hornblende biotite gneiss, marble, granitoid, and amphibolite. Using X-ray diffraction, electron microprobe analysis, and Raman spectroscopy, the vanadium bearing minerals were identified as vanadium bearing rutile, schreyerite, berdesinskiite, karelianite, a member of the karelianite-eskolaite solid solution, V-bearing phlogopite, V-bearing pyrrhotite, V-bearing pyrite, goldmanite, dravite, uvite, actinolite, and unidentified V-sulphide 1, V-sulphide 2, and V-silicate 1. The mineral assemblage present at Green Giant deposit is quite similar to that at Lake Baikal, Russia. Vanadium-bearing phlogopite is primary vanadium host in the deposit, although V-bearing oxides contribute substantially to the total V concentration, even where present in very trace amounts.

Filter Cake, which contains leachable nickel and vanadium above the criteria in the Alberta Waste Control Regulation, is produced at an oil sands facility operated by Nexen Inc. and is currently being disposed in a landfill. Bench scale and field tests were performed with stabilization/solidification (S/S) treatment reagents such as Portland cement, fly ash, elemental sulphur, and CETCO Oilfield Service’s proprietary reagents to assess their efficacy at reducing leachable metals in Filter Cake. The CETCO reagents were the most effective treatment for reducing leachable nickel and vanadium in Filter Cake. Treatments with Portland cement were successful in bench scale tests, but inconsistent in field tests. The inconsistent results obtained for Portland cement may have been due to interferences of the cement reactions from factors such as fine particulates. S/S treatments of Filter Cake present a viable waste management option. However, the associated reduced cost and environmental impacts were not substantial.

The products of vanadium metal atom reactions with propene and some propene isotopomers (propene-d6 and propene-3,3,3-d3) are investigated using FT-IR matrix isolation. The major product from the condensation of V atoms with propene at elevated mole ratios is found to be propane (C3H8), the production of which is seen to increase as concentration of propene increases. Additionally a matrix isolated product formed after metal atom insertion into the C-H bond of propene at low propene mole ratios is isolated and identified. The location of the insertion site is identified as one of the methyl hydrogen carbon bonds. The structure of the product is identified as an allyl vanadium hydride complex, through a FT-IR matrix isolation study of propene isotopomers. It is also shown that this primary product acts as an intermediate in the formation of propane. A full mechanism for the proposed formation of propane from sacrificial hydrogenation is proposed and compared with the reported mechanism for the similar reaction involving ethene. The mechanistic identification of the hydrogenation of propene is shown as a generalization of the previous reaction involving ethene. Photochemistry of reactants and intermediates trapped in the matrix are investigated. Irradiation of matrices with several different UV-visible wavelength ranges indicate that no further chemistry occurs after formation of the matrix and further irradiation has no effect on intermediates or reactants. Additionally the reactivity of water with vanadium and propene under low propene concentration conditions is also studied. Results from this study show that under all conditions studied no incorporation of water into the propene molecule is found. / Thesis (Master, Chemistry) -- Queen's University, 2009-08-10 11:15:55.312

No description available.

The Cdc25 phosphatases are highly conserved from yeast through humans and play pivotal roles in regulating the activities of cyclin-dependent kinases (Cdks). Cdc25A is one of three human Cdc25 family members, and has previously been shown to be overexpressed in numerous cancers and to transform rodent fibroblasts. Cdc25A therefore represents a rational target for chemotherapeutic development. Further, a thorough understanding of its biology and regulation in normal and transformed cells may facilitate the development of strategies to specifically interfere with the proliferation of cancerous cells. In this work I describe experiments which demonstrate that bisperoxoVanadium compounds, and specifically bpV(Me2Phen), inhibit Cdc25A phosphatase in vitro and in vivo. Further, these compounds cause cell-cycle arrest, are cytotoxic to cancer cells, and slow the growth of tumours in mouse models. With respect to the fundamental biology of Cdc25A, I have identified a sequence element (NLS) responsible for nuclear localization of Cdc25A phosphatase. An analysis of this sequence demonstrated high conservation of flanking phosphoacceptor sites, notably Serine 292. S292 was predicted to be a consensus PKA or CamKII substrate. Using site-directed mutagenesis I have shown that S292 is the sole site of PKA phosphorylation in vitro. The functional importance of S292 phosphorylation was investigated via transfections of phospho-mimetic mutants of S292 (S292E) expressed as GFP-fusion proteins; these studies indicate that S292 phosphorylation may promote nuclear localization. Studies by other groups have indicated that S292 is a phosphorylation site for inhibitory kinases, namely Chk1 and Chk2 (4). I generated a phospho-specific antibody to this site and demonstrate by immunofluorescence and western blotting an unexpected pattern of S292 phosphorylation associated with nuclear bodies and the mitotic apparatus. I provide evidence to suggest that these sites represent local fine-tuning of Cdc25A, allowing Cdk activity to be controlled at the level of specific subcellular structures. These studies highlight the complexity of Cdc25 regulation and indicate a previously unappreciated degree of control of their activity such that these enzymes exist in multiple discrete pools within a given cell.

The purpose of this project was to determine the vanadium bearing ore minerals present at the Green Giant vanadium-graphite deposit in the S.W. of Madagascar owned by Toronto based Energizer Resources Inc. The rocks are mainly quartzofeldspathic gneiss, with alternating bands of hornblende biotite gneiss, marble, granitoid, and amphibolite. Using X-ray diffraction, electron microprobe analysis, and Raman spectroscopy, the vanadium bearing minerals were identified as vanadium bearing rutile, schreyerite, berdesinskiite, karelianite, a member of the karelianite-eskolaite solid solution, V-bearing phlogopite, V-bearing pyrrhotite, V-bearing pyrite, goldmanite, dravite, uvite, actinolite, and unidentified V-sulphide 1, V-sulphide 2, and V-silicate 1. The mineral assemblage present at Green Giant deposit is quite similar to that at Lake Baikal, Russia. Vanadium-bearing phlogopite is primary vanadium host in the deposit, although V-bearing oxides contribute substantially to the total V concentration, even where present in very trace amounts.

No description available.

Zolis-gelis procesas, kuris turi potencialiai didelę technologinę vertę, leidžia sukurti medžiagas, kurių unikalios struktūros ir savybės yra retai gaunamos naudojant kitus metodus. Šio darbo užduotis- pagaminti Vanadžio-Titano-hidrochinono oksidinę bronzą panaudojant zolis-gelis technologiją bei ištirti vanadžio ir titano jonų valentingumą juose naudojant Rentgeno fotoelektronų spektroskopijos metodą. Darbe aprašoma Zolio-Gelio technologijos pagrindai, Rentgeno fotoelektronų spektroskopija ir jos spinduliuotės prietaisai, bei matavimo metodika. Aprašyti eksperimentiniai bronzos ir vanadžio – titano- hidrochinono kserogelio Rentgeno Fotoelektronų spektrai. Darbe pateikti ir lyginami grafikai buvo braižomi paisnaudojus įvairiomis programomis (SDP, XPS ir Origin). Apibendrinant šio darbo rezultatus, galima teigti, jog Vanadžio- Titano- hidrohinono kserogelyje vanadis yra V5+, V4+ ir V3+ būsenose, o deguonies jonai surišti su vanadžiu, hidroksilinėmis grupėmis ir molekuliniu vandeniu. Vanadžio- Titano- hidrochinono kserogelio kaitinimas aplinkos atmosferoje iki 580K leidžia visiškai pašalinti iš kserogelio chemiškai surišta vandenį, tai yra pereiti nuo kserogelio prie bronzos. / Sol-gel process, which has a potentially high technological value, allows you to create materials with unique structure and properties are reraly generated using other methods. This work made the task – Vanadium-Titanium-hydroquinone oxidic bronze using the sol-gel technology and study of vanadium and titanium ion valence them using X- ray photoelectron spectroscopy. The paper describes the sol-gel technology basics, X-ray photoelectron spectroscopy radiation devices, and measurement techniques. Describe the experimental and vanadium - titanium - hydroquinone xerogels and bronze X-ray photoelectron spectra. The paper presents and compares graphs were drawn from this various programs (SDP, XPS and Original). Summing up the results, one can argue that the vanadium-titanium in xerogel is V5+, V4+ and V3+ states and the oxygen ions are bound to vanadium hydroxyl groups and molecular water. Vanadium- titanium-hydroquinone xerogels heating in the atmosphere to 580K allows to completely remove from the xerogels chemically bound water which is the transition from xerogels to bronze. Vanadium and titanium ions in the bronze are in stable V5+ and Ti4+ states respectively.

The objective of this thesis is to calibrate two oxygen barometers for kimberlite magmas in the system CaO-MgO-Al2O3-SiO2-TiO2-FeO based on the Fe and V content of monticellite, CaMgSiO4, that may be utilized in cases where oxides in olivine phenocrysts and perovskite are absent from a kimberlite pipe. I first calibrate a new oxygen barometer for kimberlite magmas based on the Fe content of monticellite in equilibrium with kimberlite liquids in experiments at 100kPa from 1230 to 1350C and at fO2 from NNO-4.1 to NNO+5.3 (where NNO is the nickel-nickel oxide buffer). The XFeMtc/XFeliq (where XFeMtc/XFeliq is the ratio of mole fraction of total Fe in monticellite and Fe in liquid) decreases with increasing fO2, consistent with only Fe2+ entering the monticellite structure. Although the XFe in monticellite varies with temperature and bulk composition, these dependencies are small (0.03) compared to that with fO2. The experimental data were fitted by weigted least square regression to the following relationship: DNNO= (log (0.858(0.021)*XFeliq/XFeMtc-1)-0.139(0.022))/0.193(0.004) (uncertainties at 2 sigma). I apply this oxygen barometer to natural kimberlite assuming the bulk rock FeO is that of their liquid FeO. Monticellite compositions of five kimberlites from both literature and my own investigations revealed a range in fO2 from NNO-3.5 to NNO+1.7. I finally use my well-defined monticellite-liquid Kd Fe2+-Mg to derive a range of Mg/(Mg+Fe2+) (Mg number) for kimberlite melts of 0.40-0.90. This range in composition is broader than previous estimates of 'primary' kimberlites, reflecting the diverse mantle sources and processes that occur during generation and ascent of kimberlites. Second, I calibrate a new oxygen barometer for kimberlite magmas based on the V content of monticellite in equilibrium with kimberlite liquids doped with 0.5 wt% V2O5 at 100kPa at 1280 and 1350C and at fO2 from NNO-4.1 to NNO_0.5. The DV Mtc/liq (DV Mtc/liq = V (ppm) in monticellite/V (ppm) in liquid) decreases with increasing fO2. The partitioning data can be fitted to a model consistent with V5+ as the dominant species in the melt phase above NNO whereas V4+ dominates below those conditions in kimberlitic magmas. The total DV Mtc/liq, which embodies both DV3+ Mtc/liq and DV4+ Mtc/liq, shows a very slight temperature and bulk composition dependence. The experimental data can be fitted by weighted least square regression to the following relationship: DNNO= (log(0.354(1.785)*Vliq/VMtc-1)-1.172(2.302))/0.111(0.071) (uncertainties at 2 sigma and V in ppm). In order to apply this oxygen barometer rigorously, the V concentrations of the kimberlite melt coexisting with monticellite need to be constrained. In contrast to the Fe-in-monticellite oxygen barometer for which the concentration of Fe in monticellite was close to that of the whole rock composition, the concentration of V in the bulk rock composition reflects mostly the large accumulation of olivine xenocrysts which contain low V concentrations. For that reason, the V-in-monticellite oxygen barometer cannot be applied to natural kimberlites until we find a way to overcome this problem. The vanadium concentrations of kimberlite melts are likely higher than the V concentrations of the whole rock compositions leading to underestimated fO2 values. / Graduate