427 research outputs found

    The Contagion Effect of Compensation Regulation: Evidence From China

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    To shed light on whether and how firms changed compensation practices in response to a shift in the environment in which they operated, we examine whether there is contagion effect of executive compensation regulation on state-owned enterprises (SOEs) in the emerging market of China. Specifically, we investigate whether firms not directly affected by the changing regulatory environment nonetheless changed executive compensation in response to the actions of the directly affected firms, which is called contagion effect. We further examine the specific contagion mechanisms and the economic consequences of regulation on compensation. We find that the regulation has a significant effect on compensation gap in central SOEs and a contagion effect on local SOEs but not for non-SOEs. Within SOEs, there is an intra-industry contagion effect of compensation regulation but not an intra-region effect. Further, central SOEs and local SOEs experience reduced firm performance after the compensation regulations, but not the non-SOEs; indicating that the compensation regulation does not have favorable economic consequences for both the directly affected central SOEs and the indirectly affected local SOEs

    Integrated siRNA design based on surveying of features associated with high RNAi effectiveness

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    BACKGROUND: Short interfering RNAs have allowed the development of clean and easily regulated methods for disruption of gene expression. However, while these methods continue to grow in popularity, designing effective siRNA experiments can be challenging. The various existing siRNA design guidelines suffer from two problems: they differ considerably from each other, and they produce high levels of false-positive predictions when tested on data of independent origins. RESULTS: Using a distinctly large set of siRNA efficacy data assembled from a vast diversity of origins (the siRecords data, containing records of 3,277 siRNA experiments targeting 1,518 genes, derived from 1,417 independent studies), we conducted extensive analyses of all known features that have been implicated in increasing RNAi effectiveness. A number of features having positive impacts on siRNA efficacy were identified. By performing quantitative analyses on cooperative effects among these features, then applying a disjunctive rule merging (DRM) algorithm, we developed a bundle of siRNA design rule sets with the false positive problem well curbed. A comparison with 15 online siRNA design tools indicated that some of the rule sets we developed surpassed all of these design tools commonly used in siRNA design practice in positive predictive values (PPVs). CONCLUSION: The availability of the large and diverse siRNA dataset from siRecords and the approach we describe in this report have allowed the development of highly effective and generally applicable siRNA design rule sets. Together with ever improving RNAi lab techniques, these design rule sets are expected to make siRNAs a more useful tool for molecular genetics, functional genomics, and drug discovery studies

    Biomechanical, ultrastructural, and electrophysiological characterization of the non-human primate experimental glaucoma model.

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    Laser-induced experimental glaucoma (ExGl) in non-human primates (NHPs) is a common animal model for ocular drug development. While many features of human hypertensive glaucoma are replicated in this model, structural and functional changes in the unlasered portions of trabecular meshwork (TM) of laser-treated primate eyes are understudied. We studied NHPs with ExGl of several years duration. As expected, ExGl eyes exhibited selective reductions of the retinal nerve fiber layer that correlate with electrophysiologic measures documenting a link between morphologic and elctrophysiologic endpoints. Softening of unlasered TM in ExGl eyes compared to untreated controls was observed. The degree of TM softening was consistent, regardless of pre-mortem clinical findings including severity of IOP elevation, retinal nerve fiber layer thinning, or electrodiagnostic findings. Importantly, this softening is contrary to TM stiffening reported in glaucomatous human eyes. Furthermore, microscopic analysis of unlasered TM from eyes with ExGl demonstrated TM thinning with collapse of Schlemm's canal; and proteomic analysis confirmed downregulation of metabolic and structural proteins. These data demonstrate unexpected and compensatory changes involving the TM in the NHP model of ExGl. The data suggest that compensatory mechanisms exist in normal animals and respond to elevated IOP through softening of the meshwork to increase outflow

    Replication Stress Induces Micronuclei Comprising of Aggregated DNA Double-Strand Breaks

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    BACKGROUND: Micronuclei (MN) in mammalian cells serve as a reliable biomarker of genomic instability and genotoxic exposure. Elevation of MN is commonly observed in cells bearing intrinsic genomic instability and in normal cells exposed to genotoxic agents. DNA double-strand breaks are marked by phosphorylation of H2AX at serine 139 (γ-H2AX). One subclass of MN contains massive and uniform γ-H2AX signals. This study tested whether this subclass of MN can be induced by replication stress. PRINCIPAL FINDINGS: We observed that a large proportion of MN, from 20% to nearly 50%, showed uniform staining by antibodies against γ-H2AX, a marker of DNA double-strand breaks (DSBs). Such micronuclei were designated as MN-γ-H2AX (+). We showed that such MN can be induced by chemicals that are known to cause DNA replication stress and S phase arrest. Hydroxyurea, aphidicolin and thymidine could all significantly induce MN-γ-H2AX (+), which were formed during S phase and appeared to be derived from aggregation of DSBs. MN-γ-H2AX (-), MN that were devoid of uniform γ-H2AX signals, were induced to a lesser extent in terms of fold change. Paclitaxel, which inhibits the disassembly of microtubules, only induced MN-γ-H2AX (-). The frequency of MN-γ-H2AX (+), but not that of MN-γ-H2AX (-), was also significantly increased in cells that experience S phase prolongation due to depletion of cell cycle regulator CUL4B. Depletion of replication protein A1 (RPA1) by RNA interference resulted in an elevation of both MN-γ-H2AX (+) and MN-γ-H2AX (-). CONCLUSIONS/SIGNIFICANCE: A subclass of MN, MN-γ-H2AX (+), can be preferentially induced by replication stress. Classification of MN according to their γ-H2AX status may provide a more refined evaluation of intrinsic genomic instabilities and the various environmental genotoxicants

    Simultaneous determination of caffeic acid and rosmarinic acid in Ziziphora clinopodioides Lam. from different sources in Xinjiang by a novel rapid resolution liquid chromatography method

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    A simple and sensitive rapid resolution liquid chromatography method with a short run time was developed for the simultaneous determination of caffeic acid and rosmarinic acid in Ziziphora clinopodioides Lam. A good chromatographic separation was obtained on an XDB-C18 reversed-phase analytical column (50 mm × 4.6 mm, 1.8 μm) by gradient elution with methanol and water containing 1 % acetic acid (v/v) at 0.9 mL/min flow rate. The detection wavelength was set at 330 nm. The mean recoveries of the two compounds were 101.6 % for caffeic acid and 104.2 % for rosmarinic acid. The method was successfully applied to determine the two compounds in 10 Z. clinopodioides Lam. samples of different origins. A significant variation in the contents of the two compounds among the 10 samples was observed. Therefore, this method provides a new basis for the overall routine quality control assessment of Z. clinopodioides Lam.Colegio de Farmacéuticos de la Provincia de Buenos Aire

    Spaceborne LiDAR Surveying and Mapping

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    Laser point cloud data have the characteristics of high elevation accuracy, fast processing efficiency, strong three-dimensional (3D) vision, and wide application fields. It will be one of the core datasets of the new generation national global topographic database. The rapid advancement of spaceborne laser earth observation technology allows the collection of global 3D point cloud data, which has brought a new breakthrough in the field of satellite-based earth observation, and its significant advantages of all-day time, high accuracy and high efficiency will lead the future development of space precise mapping technology. This chapter firstly introduces the principle and development status of satellite-based LiDAR technology, then presents the basic technical framework of satellite-based LiDAR 3D mapping, and analyzes the data processing methods of spaceborne photon point clouds, and finally, focuses on the application research in various fields including precise geolocation of combined with satellite images, fusion of multi-source topographic information, polar mapping, 3D objects reconstruction, and shallow sea topographic mapping, etc
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