Pericentrin, a conserved centrosomal component, provides the structural scaffold to anchor numerous centrosomal proteins, and thus plays an essential role in the organization and function of the centrosome and the mit...Pericentrin, a conserved centrosomal component, provides the structural scaffold to anchor numerous centrosomal proteins, and thus plays an essential role in the organization and function of the centrosome and the mitotic spindle. Although pericentrin was shown to localize in the cytoplasm and reported to be sensitive to leptomycin B （LMB）, a specific inhibitor of Crml, the regions within pericentrin that serve as signals for transporting in and out of the nucleus have not yet been identified. In this study, we identified five novel nuclear export signals （NESs） in pericentrin with diverse export activities. All of the five NESs could bind to Crml in a LMB-sensitive way when mediating the nuclear export of pericentrin. We also demonstrated that the region of amino acids 8-42 in pericentrin contains a tripartite nuclear localization signal （NLS） consisting of three clusters of basic amino acids. The NLS of pericentrin binds to importin β directly or via the adaptor importin α to form the import complex, which could be disrupted by RanQ69L, a dominant-negative Ran GTPase possessing high affinity for importin β. Furthermore, we found that mutation of the NESs in full-length pericentrin results in both nuclear and cytoplasmic localization, and mutation of the NLS abolishes the nuclear import of pericentrin. On the basis of these results, we suggest that the NESs and NLS of pericentrin are essential for its subcellular localization and nucleocytoplasmic trafficking during the cell cycle.展开更多
Although over the years, Xi＇an City Image has formed clear public perception imagery, but the lack of a distinctive strategic positioning made the image of the city has not yet achieved the unity of understanding. It...Although over the years, Xi＇an City Image has formed clear public perception imagery, but the lack of a distinctive strategic positioning made the image of the city has not yet achieved the unity of understanding. It is not conducive to the dissemination of the Xi＇an city image and improves core competitiveness. Stand at a different angle on the image of the city of Xi＇an positioning the current situation, different leaders, experts and scholars put forward a different position, the positioning feature of the overall showing as abstract and fuzzy. As an attempt, by analyzing the Xi＇an government documents and the Xi＇an real advantages as well as its competitiveness in the country, this article will re-position the city image of Xi＇an.展开更多
Abstract Option pricing problem plays an extremely important role in quantitative finance. In com- plete market, Black-Scholes-Merton theory has been central to the development of financial engineering as both discipl...Abstract Option pricing problem plays an extremely important role in quantitative finance. In com- plete market, Black-Scholes-Merton theory has been central to the development of financial engineering as both discipline and profession. However, in incomplete market, there are not any replicating port- folios for those options, and thus, the market traders cannot apply the law of one price for obtaining a unique solution. Fortunately, the authors can get a fair price via local-equilibrium principle. In this paper, the authors apply the stochastic control theory to price the exotic option-barrier options, and analyze the relationship between the price and the current positions. The authors get the explicit expression for the market price of the risk. The position effect plays a significant role in option pricing, because it can tell the trader how many and which direction to trade with the market in order to reach the local equilibrium with the market.展开更多
文摘Pericentrin, a conserved centrosomal component, provides the structural scaffold to anchor numerous centrosomal proteins, and thus plays an essential role in the organization and function of the centrosome and the mitotic spindle. Although pericentrin was shown to localize in the cytoplasm and reported to be sensitive to leptomycin B （LMB）, a specific inhibitor of Crml, the regions within pericentrin that serve as signals for transporting in and out of the nucleus have not yet been identified. In this study, we identified five novel nuclear export signals （NESs） in pericentrin with diverse export activities. All of the five NESs could bind to Crml in a LMB-sensitive way when mediating the nuclear export of pericentrin. We also demonstrated that the region of amino acids 8-42 in pericentrin contains a tripartite nuclear localization signal （NLS） consisting of three clusters of basic amino acids. The NLS of pericentrin binds to importin β directly or via the adaptor importin α to form the import complex, which could be disrupted by RanQ69L, a dominant-negative Ran GTPase possessing high affinity for importin β. Furthermore, we found that mutation of the NESs in full-length pericentrin results in both nuclear and cytoplasmic localization, and mutation of the NLS abolishes the nuclear import of pericentrin. On the basis of these results, we suggest that the NESs and NLS of pericentrin are essential for its subcellular localization and nucleocytoplasmic trafficking during the cell cycle.
文摘Although over the years, Xi＇an City Image has formed clear public perception imagery, but the lack of a distinctive strategic positioning made the image of the city has not yet achieved the unity of understanding. It is not conducive to the dissemination of the Xi＇an city image and improves core competitiveness. Stand at a different angle on the image of the city of Xi＇an positioning the current situation, different leaders, experts and scholars put forward a different position, the positioning feature of the overall showing as abstract and fuzzy. As an attempt, by analyzing the Xi＇an government documents and the Xi＇an real advantages as well as its competitiveness in the country, this article will re-position the city image of Xi＇an.
基金supported by the National Natural Science Foundation of China under Grant No.9732007CB814901
文摘Abstract Option pricing problem plays an extremely important role in quantitative finance. In com- plete market, Black-Scholes-Merton theory has been central to the development of financial engineering as both discipline and profession. However, in incomplete market, there are not any replicating port- folios for those options, and thus, the market traders cannot apply the law of one price for obtaining a unique solution. Fortunately, the authors can get a fair price via local-equilibrium principle. In this paper, the authors apply the stochastic control theory to price the exotic option-barrier options, and analyze the relationship between the price and the current positions. The authors get the explicit expression for the market price of the risk. The position effect plays a significant role in option pricing, because it can tell the trader how many and which direction to trade with the market in order to reach the local equilibrium with the market.
