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Shaoyong Jiang Jon Woodhead Jimin Yu Jiayong Pan Qiling Liao Nanping Wu 《科学通报(英文版)》2002,47(3):247-250
The Jinman deposit is a low-temperature hydrothermal vein-type copper deposit, which occurs along faults and fractures within Middle Jurassic sandstone and mudstone units of the Lanping-Simao Mesozoic-Cenozoic basin of Yunnan Province. In this note, we report for the first time the Cu isotopic compositions of Cu-sulfides from the Jinman deposit. The data show large variations and low δ65Cu values of -3.70‰ to +0.30‰, which are in sharp contrast to the δ65Cu values of high-temperature magmatic-hydrothermal copper deposits (-0.62‰ to +0.40‰) and the modern ocean-floor massive sulfide deposits (-0.48‰ to +1.15‰). It is suggested that the Cu isotope fractionation at Jinman is affected mainly by the following factors, i.e. a low temperature of ore formation (150—286℃); a sedimentary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming processes. 相似文献
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The Jinman deposit is a low-temperature hydrothermal vein-type copper deposit, which occurs along faults and fractures within Middle Jurassic sandstone and mudstone units of the Lanping-Simao Mesozoic-Cenozoic basin of Yunnan Province. In this note, we report for the first time the Cu isotopic compositions of Cu-sulfides from the Jinman deposit. The data show large variations and low 65Cu values of 3.70‰ to +0.30‰, which are in sharp contrast to the 65Cu values of high-temperature magmatic-hydrothermal copper deposits (0.62‰ to +0.40‰) and the modern ocean-floor massive sulfide deposits (0.48‰ to +1.15‰). It is suggested that the Cu isotope fractionation at Jinman is affected mainly by the following factors, i.e. a low temperature of ore formation (150-286℃); a sedimentary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming processes. 相似文献
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Contraction of muscle involves the cyclic interaction of myosin heads on the thick filaments with actin subunits in the thin filaments. Muscles relax when this interaction is blocked by molecular switches on either or both filaments. Insight into the relaxed (switched OFF) structure of myosin has come from electron microscopic studies of smooth muscle myosin molecules, which are regulated by phosphorylation. These studies suggest that the OFF state is achieved by an asymmetric, intramolecular interaction between the actin-binding region of one head and the converter region of the other, switching both heads off. Although this is a plausible model for relaxation based on isolated myosin molecules, it does not reveal whether this structure is present in native myosin filaments. Here we analyse the structure of a phosphorylation-regulated striated muscle thick filament using cryo-electron microscopy. Three-dimensional reconstruction and atomic fitting studies suggest that the 'interacting-head' structure is also present in the filament, and that it may underlie the relaxed state of thick filaments in both smooth and myosin-regulated striated muscles over a wide range of species. 相似文献
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