47 research outputs found

    Feeling Right at Home: Hometown CEOs and Firm Innovation  

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    Extending the theories of social and place identity, we predict that CEO hometown identity has a positive and significant influence on firm innovation. Our empirical evidence, from publicly traded firms in China during 2002–2016, suggests that a firm whose CEO's hometown is in the same province or city as the firm's headquarters tends to invest more in R&D and generate more patent applications. Our results are robust to the firm fixed effects and we use difference-in-differences analysis and instrument variable regressions to mitigate endogeneity concerns. CEOs' hometown identity still has a strong and positive impact on innovation after we control for measures of social capital of CEOs. We identify the mechanisms behind the positive relation between firm innovation and CEO hometown identity: hometown CEOs enjoy more support from the board of directors, they are more willing to take risks, and they are more likely to have long-term visions

    Horseradish Peroxidase-Carrying Electrospun Nonwoven Fabrics for the Treatment of o-Methoxyphenol

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    The carboxyl-functionalized polystyrene (poly(styrene-co-methacrylic acid), PSMAA) nanofibers with average diameters of 250 ± 20 nm was prepared by electrospinning. PSMAA nanofibrous membrane were employed for immobilization of horseradish peroxidase (HRP) enzyme on the fibrous surface by a chemical method. The parameters about immobilizing HRP on the PSMAA nanofibers were studied and the influence on the activity of the HRP is discussed. This study showed that soap-free emulsion method is an ideal technology to modify the polystyrene surface and ultimately achieve enzyme immobilization on electrospun PSMAA nanofibers surfaces. Compared with free HRP, the acid-base stability, thermal stability, and storage stability of HRP were increased after the immobilization. The immobilized HRP maintained about 60% of its initial activity during a 20-day storage period. However, the free HRP maintained only 40% of its initial activity. The removal percentages of o-methoxyphenol (OMP) reached 80.2% after 120 min for immobilized HRP. These results suggest that the proposed scheme for immobilization of HRP has potential in industrial applications for the treatment of phenolic wastewater

    Enhancing the benefit of slide steering drilling systems in horizontal wells of unconventional reservoirs

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    The slide steering drilling system consisting of a bent positive displacement motor (PDM) and measurement while drilling (MWD) system is widely used to continuously implement all wellpath control operations by alternately applying the slide and compound drilling modes. Due to the large friction force on the drilling string during slide drilling in the horizontal section, there is a significant adverse impact on both the drilling speed and horizontal extension ability. To efficiently and economically drill long horizontal sections, it is essential to increase the compound drilling proportion and decrease the alternative times of the two drilling modes. According to the features of wavy or tortuous horizontal sections and wellpath calculation models, a prediction and control method for the compound drilling proportion of horizontal sections is first established, and subsequently, its influencing factors and laws are analyzed and verified using an example. Theoretical research and drilling practice have shown that the compound drilling proportion of the horizontal section depends on the build-up rate of slide drilling and the inclination and azimuth change rates of compound drilling and is independent of the target area parameters and wellpath fluctuation ratio. In order to increase the compound drilling proportion and reduce the slide drilling frequency in the horizontal section, it is necessary to increase the build-up rate of slide drilling properly and reduce the inclination and azimuth change rates of compound drilling to the greatest extent. This paper is helpful to enhance the benefit of slide steering drilling systems in horizontal wells of unconventional reservoirs

    Comparison Study of Gold Nanohexapods, Nanorods, and Nanocages for Photothermal Cancer Treatment

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    Gold nanohexapods represent a novel class of optically tunable nanostructures consisting of an octahedral core and six arms grown on its vertices. By controlling the length of the arms, their localized surface plasmon resonance peaks could be tuned from the visible to the near-infrared region for deep penetration of light into soft tissues. Herein we compare the in vitro and in vivo capabilities of Au nanohexapods as photothermal transducers for theranostic applications by benchmarking against those of Au nanorods and nanocages. While all these Au nanostructures could absorb and convert near-infrared light into heat, Au nanohexapods exhibited the highest cellular uptake and the lowest cytotoxicity in vitro for both the as-prepared and PEGylated nanostructures. In vivo pharmacokinetic studies showed that the PEGylated Au nanohexapods had significant blood circulation and tumor accumulation in a mouse breast cancer model. Following photothermal treatment, substantial heat was produced in situ and the tumor metabolism was greatly reduced for all these Au nanostructures, as determined with ^(18)F-flourodeoxyglucose positron emission tomography/computed tomography (^(18)F-FDG PET/CT). Combined together, we can conclude that Au nanohexapods are promising candidates for cancer theranostics in terms of both photothermal destruction and contrast-enhanced diagnosis

    Histone Deacetylase Inhibitors Selectively Target Homology Dependent DNA Repair Defective Cells and Elevate Non-Homologous Endjoining Activity

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    Background: We have previously used the ATAD5-luciferase high-throughput screening assay to identify genotoxic compounds with potential chemotherapeutic capabilities. The successful identification of known genotoxic agents, including the histone deacetylase inhibitor (HDACi) trichostatin A (TSA), confirmed the specificity of the screen since TSA has been widely studied for its ability to cause apoptosis in cancer cells. Because many cancers have acquired mutations in DNA damage checkpoints or repair pathways, we hypothesized that these cancers may be susceptible to treatments that target compensatory pathways. Here, we used a panel of isogenic chicken DT40 B lymphocyte mutant and human cell lines to investigate the ability of TSA to define selective pathways that promote HDACi toxicity. Results: HDACi induced a DNA damage response and reduced viability in all repair deficient DT40 mutants although ATM-nulls were least affected. The most dramatic sensitivity was observed in mutants lacking the homology dependent repair (HDR) factor BLM or the non-homologous end-joining (NHEJ) and HDR factors, KU/RAD54, suggesting an involvement of either HDR or NHEJ in HDACi-induced cell death. To extend these findings, we measured the frequencies of HDR and NHEJ after HDACi treatment and monitored viability in human cell lines comparably deficient in HDR or NHEJ. Although no difference in HDR frequency was observed between HDACi treated and untreated cells, HDR-defective human cell lines were clearly more sensitive than wild type. Unexpectedly, cells treated with HDACis showed a significantly elevated NHEJ frequency. Conclusions: HDACi targeting drugs induced significant increases in NHEJ activity in human cell lines but did not alter HDR frequency. Moreover, HDR is required for cellular resistance to HDACi therapy; therefore, NHEJ does not appear to be a critical axis for HDACi resistance. Rather, HDACi compounds induced DNA damage, most likely double strand breaks (DSBs), and HDR proficiency is correlated with cell survivalclose4

    Horseradish Peroxidase-Carrying Electrospun Nonwoven Fabrics for the Treatment of o-Methoxyphenol

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    The carboxyl-functionalized polystyrene (poly(styrene-co-methacrylic acid), PSMAA) nanofibers with average diameters of 250 ± 20 nm was prepared by electrospinning. PSMAA nanofibrous membrane were employed for immobilization of horseradish peroxidase (HRP) enzyme on the fibrous surface by a chemical method. The parameters about immobilizing HRP on the PSMAA nanofibers were studied and the influence on the activity of the HRP is discussed. This study showed that soap-free emulsion method is an ideal technology to modify the polystyrene surface and ultimately achieve enzyme immobilization on electrospun PSMAA nanofibers surfaces. Compared with free HRP, the acid-base stability, thermal stability, and storage stability of HRP were increased after the immobilization. The immobilized HRP maintained about 60% of its initial activity during a 20-day storage period. However, the free HRP maintained only 40% of its initial activity. The removal percentages of o-methoxyphenol (OMP) reached 80.2% after 120 min for immobilized HRP. These results suggest that the proposed scheme for immobilization of HRP has potential in industrial applications for the treatment of phenolic wastewater

    The experimental study on the high-voltage electrodes absorption water phenomenon

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    Abstract: This paper reports the result of the high-voltage electrodes absorption water experimental phenomenon. When the high voltage power supply output is positive, the mist biases anode plate; when the high voltage power supply output is negative, the mist biases cathode plate; When the high voltage power pulse output is positive or negative, the mist does not deviate from the direction of entrance. Absorption water is proportional to the size of the power supply output and duration, that is to say: if the time is fixed, the higher the voltage, the greater the electrode absorption water; if the power output voltage is fixed, the longer the electrode continues, the more water gathers. We find that the phenomenon of high-voltage electrode is different from water accumulation which is reported in according to the analysis of experimental results, and the mechanism of its occurrence remains to be studied further

    Hydrothermal synthesis, characterization and acid catalytic activity of nano Ce-La oxide powder

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    1270-1272Ce-La oxide powder has been synthesized by hydrothermal method at 250ºC using cerous nitrate, lanthanum nitrate and hydrazine hydrate as raw materials and characterized by X-ray diffraction, transmission electron microscopy and infrared spectra. The acid catalytic performance of the sample has been investi-gated in the reaction of acetic acid and n-butyl alcohol. The results show that La³⁺ is embedded into the cubic crystal lattice of CeO₂ and forms a homogeneous solid structure. The particle diameter of sample is less than 50 nm. Ce-La oxide solid solution possesses higher acid catalytic performance and its catalytic mechanism is of the proton acid catalysis type
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