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To evaluate the effects of phacoemulsification energy on the redox state and mitochondrial distribution of cultured human endothelial cells. Methods: Human corneal endothelial cells from fresh banked human donor tissue not suitable for transplantation were harvested and cultured. Cellular autofluorescence images were obtained using an inverted microscope. The redox fluorometric ratio, which can be related to oxidative stress, was calculated as the net value of fluorescence from the 4,6-diamidino-2-phenylindole channel divided by the net value of fluorescence from the fluorescein isothiocyanate-conjugated channel after subtraction of background. For determining the mitochondrial distribution patterns, the cell area was divided by drawing a line halfway between the nuclear and cell membranes. The average fluorescence in the central area was divided by the average fluorescence in the peripheral area. This ratio was compared. Results: Human corneal endothelial cells exposed to increasing phacoemulsification times and increasing ultrasonic energy levels displayed dose-dependent decreases in measured redox ratios. Lower redox ratios in response to phacoemulsification did not associate with decreases in cell size or altered patterns of mitochondrial localization. Conclusion: Redox fluorometry may serve as a useful indicator for the in vitro study of human corneal endothelial cell physiological response to ultrasonic stressors and potentially other nonoxidative stressors. Clinical Relevance: Redox fluorometry in combination with human corneal endothelial cell morphometric measurements has potential to serve as an indicator of human corneal endothelial cell injury resulting secondary to ultrasound phacoemulsification.

Regional till sampling was completed near four Cu porphyry mineralized zones in south-central British Columbia, Canada: Highland Valley Copper (Cu-Mo), Gibraltar (Cu-Mo), and Mount Polley (Cu-Au-Ag) deposits, and the Woodjam (Cu-Au-Mo) prospect. At all sites, Cu concentrations in the clay-sized fraction and chalcopyrite grains (0.25 – 0.5 mm; >3.2 specific gravity) are found in greater abundance in till near and down-ice from mineralized zones compared to surrounding background regions. At Mount Polley, the abundance of gold grains in till defines a dispersal train extending at least 3 km down-ice (SW and NW) from mineralization. At three sites out of four, epidote in till heavy mineral concentrates occurs in greater percentage near and down-ice from mineralized zones compared to background regions suggesting that this mineral could be an indicator of propylitic alteration associated with porphyry mineralization. The distribution pattern of Cu concentrations and chalcopyrite grains in till is controlled by the distribution of Cu-porphyry mineral occurrences in bedrock and the direction of ice-flow movements which prevailed during the last glaciation. By comparing study sites, there is a positive relationship between the areal extent of bedrock mineralization that was exposed to glacial erosion and the absolute values of Cu concentrations and chalcopyrite grain counts in till. In the Woodjam region where the till is thick (>10 m), eight samples with background Cu concentrations in the clay-sized fraction of till contain >4 grains of chalcopyrite/10 kg which is indicative of mineralization. This study demonstrates that a combination of till geochemistry and mineralogy is an efficient method for mineral exploration for Cu porphyry deposits covered by variable amounts of glacial sediments. Supplementary material: The full data sets on till geochemistry and mineralogy are available at: https://doi.org/10.6084/m9.figshare.c.3291503

Mount Polley Mine is an alkaline, silica-under saturated Cu-Au porphyry deposit owned by Imperial Metals Ltd. It is located 8 km southwest of Likely, within the Interior Plateau of British Columbia. This region was glaciated several times during the Quaternary and is predominantly covered by till. This makes it an ideal site to develop drift prospecting exploration methods for detecting buried mineralization. Glaciers are dynamic, eroding bedrock, and transporting and depositing the resulting debris as till in the direction of ice movement. If a glacier erodes mineralized bedrock, the resulting till will be enriched in elements and minerals derived from the mineralization. Porphyry mineralization and the associated alteration zones are spatially extensive, which may result in large dispersal trains in till. The objective of this research is to characterize the geochemical and mineralogical composition of till in the Mount Polley region in order to identify key indicators of porphyry mineralization in till, benefiting future exploration for porphyry deposits in areas of thick drift cover. This research is funded by the Geological Survey of Canada's Targeted Geoscience Initiative (TGI-4) program. Dominant ice flow in the Mount Polley region is to the northwest with an earlier west-southwestward flow. During the 2012 and 2013 field seasons, 87 till samples were collected up-ice, overlying and down-ice from the deposit based on these flow measurements. Elements and minerals associated with the mineralization show elevated content near the deposit, which progressively decreases towards the northwest (or down-ice direction). These include copper, silver (in the 2 ?m fraction) and gold (in the 63 ?m fraction), up to 1548 ppm, 503 ppb and 90.2 ppb, respectively. Gold grain content of up to 87 grains per 10 kg is observed in the silt-fine sand fraction. In the heavy mineral concentrates (s.g > 3.2), apatite (up to 0.5%), chalcopyrite (up to 98 grains per 10 kg), and epidote (up to 90%), observed in the 0.25 - 0.5 mm fraction. Gold grain, chalcopyrite, and epidote are excellant indicators of Mount Polley mineralization. However, apatite may not be a suitable indicator of Mount Polley mineralization in till.