4,723 research outputs found

    Supplier asset allocation in a pool-based electricity market

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    A power supplier in a pool-based market needs to allocate his generation capacities to participate in contract and spot markets. In this paper, the optimal portfolio selection theory is introduced for this purpose. A model applying this theory is proposed to solve the supplier asset allocation problem. Real market data are used in a numerical study to test the proposed model. The results show that different asset allocation solutions can yield very different risk-return tradeoffs for a supplier, and the proposed method can be potentially useful in suppliers' decision making. © 2007 IEEE.published_or_final_versio

    CHTOP in Chemoresistant Epithelial Ovarian Cancer: A Novel and Potential Therapeutic Target.

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    Objective: Chemoresistance is a major challenge in epithelial ovarian cancer (EOC) treatment. Chromatin target of protein arginine methyltransferase (CHTOP) was identified as a potential biomarker in chemoresistant EOC cell lines using label-free LC-MS/MS quantitative proteomics. Thus, the aim of this study is to investigate the role of CHTOP in chemoresistant EOC and the underlying mechanism. Methods: The expression of CHTOP in human ovarian cancer cells and tissues was detected using immunofluorescence (IF), western blot (WB), and immunohistochemistry (IHC), respectively. Flow cytometry and TUNEL assay were employed to detect the effect of CHTOP knockdown (KD) in chemoresistant EOC cell apoptosis, while colony and sphere formation assays were used to evaluate its effect on cell stemness. The association of CHTOP with cell metastasis was determined using Matrigel invasion and wound-healing assays. Results: The higher level expression of CHTOP protein was found in chemoresistant EOC cells as compared to their sensitive parental cells or normal epithelial ovarian cells. Results from IHC and bioinformatic analysis showed CHTOP was highly expressed in human ovarian cancer tissues and associated with a poor progression-free survival in patients. In addition, CHTOP KD significantly enhanced cisplatin-induced apoptosis, reduced the stemness of chemoresistant EOC cells, and decreased their metastatic potential. Conclusion: Our findings suggest that CHTOP is associated with apoptosis, stemness, and metastasis in chemoresistant EOC cells and might be a promising target to overcome chemoresistance in EOC treatment

    System Framework for Digital Monitoring of the Construction of Asphalt Concrete Pavement Based on IoT, BeiDou Navigation System, and 5G Technology

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    In the construction of asphalt pavement, poor quality is often the main reason for damage to the pavement, which necessitates the use of monitoring systems during the construction stage. Therefore, this study focuses on building an asphalt concrete pavement construction monitoring system to monitor the construction phase. Through a literature review and semi-structured interviews with industry experts, this paper provides an in-depth understanding of the goals and obstacles of asphalt pavement monitoring and discusses directions for improvement. Subsequently, based on the analysis of the interview results, a system framework for asphalt concrete pavement construction monitoring was constructed, and the system was successfully developed and applied to a highway construction project. The results show that the monitoring system significantly improves the construction quality of asphalt concrete pavement, improves the intelligent level of pavement construction management, and promotes the digital development of highway construction

    發電商多交易策略的有效前沿分析: (一)模型的建立

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    The particular technical and institutional constraints of electric systems and electricity markets result in a significant difference between the feasible strategy set of generation companies in electricity markets and that of investors in capital markets. Despite its importance, this issue is seldom discussed in existing literature. This shortage can constitute an obstacle to the application of GMTS research fruits. For the purpose of addressing the deficiencies of the current GMTS research, the analytic tool of efficient frontier is employed to study the effects of the technical and institutional constraints on the feasible region of GMTS. One of the conclusions drawn in this paper is that the shape of GMTS efficient frontier is different from that of the efficient frontier of ordinary investment markets, which theoretically demonstrates the importance of considering the unique constraints of the electric power market in the GMTS decision.link_to_subscribed_fulltex

    發電商多交易策略的有效前沿分析: (二)算法的實現

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    In a deregulated environment, rationally diversifying the generation capacity in different trading types can help generation companies (GenCos) increase return and control risk. With regard to the difficulty in choosing a proper weight between risk and return in the research on the GenCo multi-trading strategy (GMTS), this paper develops a new computer-aided decision making tool based on the GMTS efficient frontier. The solution methodology of GMTS efficient frontier is thoroughly studied and a practical algorithm is designed. The validity and computation speed of the proposed algorithm is tested by a case study based on real world market data. Model analysis and simulation results both show that the proposed methodology has the advantages of applicability, reliability, flexible modeling and the convenience of controlling the computation time and precision.link_to_subscribed_fulltex

    Ischemic postconditioning attenuates liver warm ischemia-reperfusion injury through Akt-eNOS-NO-HIF pathway

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    <p>Abstract</p> <p>Background</p> <p>Ischemic postconditioning (IPO) has been demonstrated to attenuate ischemia/reperfusion (I/R) injury in the heart and brain, its roles to liver remain to be defined. The study was undertaken to determine if IPO would attenuate liver warm I/R injury and its protective mechanism.</p> <p>Methods</p> <p>Mice were divided into sham, I/R, IPO+I/R (occlusing the porta hepatis for 60 min, then treated for three cycles of 10 sec brief reperfusion consecutively, followed by a persistent reperfusion); L-NAME+ sham (L-NAME, 16 mg/kg, i.v., 5 min before repefusion); L-NAME+I/R; and L-NAME+ IPO. Blood flow of caudate and left lobe of the liver was blocked. Functional and morphologic changes of livers were evaluated. Contents of nitric oxide, eNOS and iNOS in serum were assayed. Concentration of eNOS, iNOS, malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in hepatic tissue were also measured. Expressions of Akt, p-Akt and HIF-1α protein were determined by western blot. Expressions of TNF-α and ICAM-1 were measured by immunohistochemistry and RT-PCR.</p> <p>Results</p> <p>IPO attenuated the dramatically functional and morphological injuries. The levels of ALT was significantly reduced in IPO+I/R group (p < 0.05). Contents of nitric oxide and eNOS in serum were increased in the IPO+I/R group (p < 0.05). IPO also up-regulated the concentration of eNOS, activity of SOD in hepatic tissue (p < 0.05), while reduced the concentration of MDA (p < 0.05). Moreover, protein expressions of HIF-1α and p-Akt were markedly enhanced in IPO+I/R group. Protein and mRNA expression of TNF-α and ICAM-1 were markedly suppressed by IPO (p < 0.05). These protective effects of IPO could be abolished by L-NAME.</p> <p>Conclusions</p> <p>We found that IPO increased the content of NO and attenuated the overproduction of ROS and I/R-induced inflammation. Increased NO contents may contribute to increasing HIF-1α level, and HIF-1α and NO would simultaneously protect liver from I/R injury. These findings suggested IPO may have the therapeutic potential through Akt-eNOS-NO-HIF pathway for the better management of liver I/R injury.</p

    Giant Biquadratic Exchange in 2D Magnets and its Role in Stabilizing Ferromagnetism of NiCl2 Monolayer

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    Two-dimensional (2D) van der Waals (vdW) magnets provide an ideal platform for exploring, on the fundamental side, new microscopic mechanisms and for developing, on the technological side, ultra-compact spintronic applications. So far, bilinear spin Hamiltonians have been commonly adopted to investigate the magnetic properties of 2D magnets, neglecting higher order magnetic interactions. However, we here provide quantitative evidence of giant biquadratic exchange interactions in monolayer NiX2 (X=Cl, Br and I), by combining first-principles calculations and the newly developed machine learning method for constructing Hamiltonian. Interestingly, we show that the ferromagnetic ground state within NiCl2 single layers cannot be explained by means of bilinear Heisenberg Hamiltonian; rather, the nearest-neighbor biquadratic interaction is found to be crucial. Furthermore, using a three-orbitals Hubbard model, we propose that the giant biquadratic exchange interaction originates from large hopping between unoccupied and occupied orbitals on neighboring magnetic ions. On a general framework, our work suggests biquadratic exchange interactions to be important in 2D magnets with edge-shared octahedra.Comment: 3 figure

    Electronic structure of warm dense copper studied by ultrafast x-ray absorption spectroscopy

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    We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is necessary

    Surface energy engineering of graphene

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    Contact angle goniometry is conducted for epitaxial graphene on SiC. Although only a single layer of epitaxial graphene exists on SiC, the contact angle drastically changes from 69{\deg} on SiC substrates to 92{\deg} with graphene. It is found that there is no thickness dependence of the contact angle from the measurements of single, bi, and multi layer graphene and highly ordered pyrolytic graphite (HOPG). After graphene is treated with oxygen plasma, the level of damage is investigated by Raman spectroscopy and correlation between the level of disorder and wettability is reported. By using low power oxygen plasma treatment, the wettability of graphene is improved without additional damage, which can solve the adhesion issues involved in the fabrication of graphene devices
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