Charlie Davies | Australian Catholic University (original) (raw)
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Papers by Charlie Davies
Many promising pharmaceutically active compounds have low solubility in aqueous environments and ... more Many promising pharmaceutically active compounds have low solubility in aqueous environments and their encapsulation into efficient drug delivery vehicles is crucial to increase their bioavailability. Lipodisq nanoparticles are approximately 10 nm in diameter and consist of a circular phospholipid bilayer, stabilized by an annulus of SMA (a hydrolysed copolymer of styrene and maleic anhydride). SMA is used extensively in structural biology to extract and stabilize integral membrane proteins for biophysical studies. Here, we assess the potential of these nanoparticles as drug delivery vehicles, determining their cytotoxicity and thein vivoexcretion pathways of their polymer and lipid components. Doxorubicin-loaded Lipodisqs were cytotoxic across a panel of cancer cell lines, whereas nanoparticles without the drug had no effect on cell proliferation. Intracellular doxorubicin release from Lipodisqs in HeLa cells occurred in the low-pH environment of the endolysosomal system, consisten...
Mineralium Deposita, 2005
El Galeno and Michiquillay are early to middle Miocene Cu-Au-Mo porphyry-related deposits located... more El Galeno and Michiquillay are early to middle Miocene Cu-Au-Mo porphyry-related deposits located in the auriferous Cajamarca district of northern Peru. The El Galeno deposit (486 Mt at 0.57% Cu, 0.14 g/t Au and 150 ppm Mo) is associated with multiple dioritic intrusions hosted within Lower Cretaceous quartzites and shales. Emplacement of the porphyry stocks (17.5-16.5 Ma) in a hanging wall anticline was structurally controlled by oblique faults superimposed on early WNW-trending fold-thrust structures. Early K-feldspar-biotite-magnetite (potassic) alteration was associated with pyrite and chalcopyrite mineralisation. A quartz-magnetite assemblage that occurs at depth has completely replaced potassically altered rocks. Late-and post-mineralisation stocks are spatially and temporally related to weak quartz-muscovite (phyllic) alteration. High Au grades are associated with early intrusive phases located near the centre of the deposit. Highest Cu grades ($0.9% Cu) are mostly associated with a supergene enrichment blanket, whilst high Mo grades are restricted to contacts with the metasedimentary rocks. The Michiquillay Cu-Au-Mo deposit (631 Mt at 0.69% Cu, 0.15 g/t Au, 100-200 ppm Mo) is associated with a Miocene (20.0-19.8 Ma) dioritic complex that was emplaced within the hanging wall of a back thrust fault. The intrusive complex is hosted in quartzites and limestones. The NE-trending deposit is crosscut by NNWtrending prospect-scale faults that influenced both alteration and metal distribution. In the SW and NE of the deposit, potassic alteration zones contain moderate hypogene grades (0.14 g/t Au and 0.8% Cu) and are characterised by chalcopyrite and pyrite mineralisation. The core of the deposit is defined by a lower grade (0.08 g/t Au and 0.57% Cu) phyllic alteration that overprinted early potassic alteration. Michiquillay contains a supergene enrichment blanket of 45-80 m thickness with an average Cu grade of 1.15%, which is overlain by a deep leached cap (up to 150 m). Cu-Au-Mo (El Galeno-Michiquillay) and Au-rich (Minas Conga) deposits in the Cajamarca region are of similar age (early-middle Miocene) and intrusive rock type (dioritic) associations. Despite these geochronological and geochemical similarities, findings from this study suggest variation in metal grade between the hybrid-type and Au-rich deposits result from a combination of physio-chemical factors. These include variations in temperature and oxygen fugacity conditions during hypogene mineralisation resulting in varied sulphide assemblages, host rock type, precipitation of ubiquitous hydrothermal magnetite, and late hydrothermal fluid flow resulting in a well-developed phyllic alteration zone.
Many promising pharmaceutically active compounds have low solubility in aqueous environments and ... more Many promising pharmaceutically active compounds have low solubility in aqueous environments and their encapsulation into efficient drug delivery vehicles is crucial to increase their bioavailability. Lipodisq nanoparticles are approximately 10 nm in diameter and consist of a circular phospholipid bilayer, stabilized by an annulus of SMA (a hydrolysed copolymer of styrene and maleic anhydride). SMA is used extensively in structural biology to extract and stabilize integral membrane proteins for biophysical studies. Here, we assess the potential of these nanoparticles as drug delivery vehicles, determining their cytotoxicity and thein vivoexcretion pathways of their polymer and lipid components. Doxorubicin-loaded Lipodisqs were cytotoxic across a panel of cancer cell lines, whereas nanoparticles without the drug had no effect on cell proliferation. Intracellular doxorubicin release from Lipodisqs in HeLa cells occurred in the low-pH environment of the endolysosomal system, consisten...
Mineralium Deposita, 2005
El Galeno and Michiquillay are early to middle Miocene Cu-Au-Mo porphyry-related deposits located... more El Galeno and Michiquillay are early to middle Miocene Cu-Au-Mo porphyry-related deposits located in the auriferous Cajamarca district of northern Peru. The El Galeno deposit (486 Mt at 0.57% Cu, 0.14 g/t Au and 150 ppm Mo) is associated with multiple dioritic intrusions hosted within Lower Cretaceous quartzites and shales. Emplacement of the porphyry stocks (17.5-16.5 Ma) in a hanging wall anticline was structurally controlled by oblique faults superimposed on early WNW-trending fold-thrust structures. Early K-feldspar-biotite-magnetite (potassic) alteration was associated with pyrite and chalcopyrite mineralisation. A quartz-magnetite assemblage that occurs at depth has completely replaced potassically altered rocks. Late-and post-mineralisation stocks are spatially and temporally related to weak quartz-muscovite (phyllic) alteration. High Au grades are associated with early intrusive phases located near the centre of the deposit. Highest Cu grades ($0.9% Cu) are mostly associated with a supergene enrichment blanket, whilst high Mo grades are restricted to contacts with the metasedimentary rocks. The Michiquillay Cu-Au-Mo deposit (631 Mt at 0.69% Cu, 0.15 g/t Au, 100-200 ppm Mo) is associated with a Miocene (20.0-19.8 Ma) dioritic complex that was emplaced within the hanging wall of a back thrust fault. The intrusive complex is hosted in quartzites and limestones. The NE-trending deposit is crosscut by NNWtrending prospect-scale faults that influenced both alteration and metal distribution. In the SW and NE of the deposit, potassic alteration zones contain moderate hypogene grades (0.14 g/t Au and 0.8% Cu) and are characterised by chalcopyrite and pyrite mineralisation. The core of the deposit is defined by a lower grade (0.08 g/t Au and 0.57% Cu) phyllic alteration that overprinted early potassic alteration. Michiquillay contains a supergene enrichment blanket of 45-80 m thickness with an average Cu grade of 1.15%, which is overlain by a deep leached cap (up to 150 m). Cu-Au-Mo (El Galeno-Michiquillay) and Au-rich (Minas Conga) deposits in the Cajamarca region are of similar age (early-middle Miocene) and intrusive rock type (dioritic) associations. Despite these geochronological and geochemical similarities, findings from this study suggest variation in metal grade between the hybrid-type and Au-rich deposits result from a combination of physio-chemical factors. These include variations in temperature and oxygen fugacity conditions during hypogene mineralisation resulting in varied sulphide assemblages, host rock type, precipitation of ubiquitous hydrothermal magnetite, and late hydrothermal fluid flow resulting in a well-developed phyllic alteration zone.