1,910 research outputs found

    Neutrinos in the holographic dark energy model: constraints from latest measurements of expansion history and growth of structure

    Full text link
    The model of holographic dark energy (HDE) with massive neutrinos and/or dark radiation is investigated in detail. The background and perturbation evolutions in the HDE model are calculated. We employ the PPF approach to overcome the gravity instability difficulty (perturbation divergence of dark energy) led by the equation-of-state parameter ww evolving across the phantom divide w=−1w=-1 in the HDE model with c<1c<1. We thus derive the evolutions of density perturbations of various components and metric fluctuations in the HDE model. The impacts of massive neutrino and dark radiation on the CMB anisotropy power spectrum and the matter power spectrum in the HDE scenario are discussed. Furthermore, we constrain the models of HDE with massive neutrinos and/or dark radiation by using the latest measurements of expansion history and growth of structure, including the Planck CMB temperature data, the baryon acoustic oscillation data, the JLA supernova data, the Hubble constant direct measurement, the cosmic shear data of weak lensing, the Planck CMB lensing data, and the redshift space distortions data. We find that ∑mν<0.186\sum m_\nu<0.186 eV (95\% CL) and Neff=3.75−0.32+0.28N_{\rm eff}=3.75^{+0.28}_{-0.32} in the HDE model from the constraints of these data.Comment: 18 pages, 5 figures; revised version accepted for publication in JCA

    Ursolic Acid Florotriazole Treatment Causes Inhibition of Squamous Cell Carcinoma through Fas Signaling Pathway

    Get PDF
    Purpose: To investigate the effect of ursolic acid florotriazole (UFT), on SCC-15 oral squamous cancer cells.Methods: Confocal laser microscope with a 490 nm argon laser was used to record the fluorescence of the cells and capture the images. Flow cytometry and Cell Quest program were used to analyze the DNA content of the stained cells. Apoptosis was characterized by YO-PRO-1 staining.Results: Treatment of SCC-15 cells with UFT for 48 h significantly reduced cell viability in a dosedependent manner. At 20 Οg/mL concentration of UFT, SCC-15, cell viability was reduced to 19 % compared to 100 % in the untreated cells (p = 0.0002). UFT treatment enhanced the proportion of apoptotic cells which was evident from YO-PRO-1 staining. In UFT-treated cultures, the population of cells in sub-G1 phase increased to 38.54 % compared to 7.32 % for control after 48 h. Expression of Fas in UFT-treated cells was also higher (p = 0.0002) than in untreated cells. In C3H/HeJ mice, administration of UFT daily for 14 days caused a significant (p = 0.0002) reduction in tumor volume and weight after 30 days of SCC-15 carcinoma cell administration.Conclusion: UFT treatment inhibits viability and induces apoptosis in squamous cell carcinoma cells through suppression of Fas expression. Therefore, UFT may be useful for the treatment of squamous cell cancer.Keywords: Ursolic acid florotriazole, Squamous cell cancer, Fas expression, Tumor volume, Cell viability, Apoptosi

    APOBEC3G-UBA2 fusion as a potential strategy for stable expression of APOBEC3G and inhibition of HIV-1 replication

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Although APOBEC3G protein is a potent and innate anti-HIV-1 cellular factor, HIV-1 Vif counteracts the effect of APOBEC3G by promoting its degradation through proteasome-mediated proteolysis. Thus, any means that could prevent APOBEC3G degradation could potentially enhance its anti-viral effect. The UBA2 domain has been identified as an intrinsic stabilization signal that protects protein from proteasomal degradation. In this pilot study, we tested whether APOBEC3G, when it is fused with UBA2, can resist Vif-mediated proteasomal degradation and further inhibit HIV-1 infection.</p> <p>Results</p> <p>APOBEC3G-UBA2 fusion protein is indeed more resistant to Vif-mediated degradation than APOBEC3G. The ability of UBA2 domain to stabilize APOBEC3G was diminished when polyubiquitin was over-expressed and the APOBEC3G-UBA2 fusion protein was found to bind less polyubiquitin than APOBEC3G, suggesting that UBA2 stabilizes APOBEC3G by preventing ubiquitin chain elongation and proteasome-mediated proteolysis. Consistently, treatment of cells with a proteasome inhibitor MG132 alleviated protein degradation of APOBEC3G and APOBEC3G-UBA2 fusion proteins. Analysis of the effect of APOBEC3G-UBA2 fusion protein on viral infectivity indicated that infection of virus packaged from HEK293 cells expressing APOBEC3G-UBA2 fusion protein is significantly lower than those packaged from HEK293 cells over-producing APOBEC3G or APOBEC3G-UBA2 mutant fusion proteins.</p> <p>Conclusion</p> <p>Fusion of UBA2 to APOBEC3G can make it more difficult to be degraded by proteasome. Thus, UBA2 could potentially be used to antagonize Vif-mediated APOBEC3G degradation by preventing polyubiquitination. The stabilized APOBEC3G-UBA2 fusion protein gives stronger inhibitory effect on viral infectivity than APOBEC3G without UBA2.</p

    Planning Hydropower Production of Small Reservoirs Under Resources and System Knowledge Uncertainty

    Get PDF
    Available energy from water varies widely from season to season, depending on precipitation and streamflows, especially in small catchments. In addition, the reservoir operation problem is associated with the inability of operators to formulate crisp boundary conditions, due to uncertainty in knowledge. In this chapter, an approach for planning the operation of small multipurpose reservoir systems for hydropower generation and flood control under consideration of the stochastic nature of inflows and initial storage levels and allowed formulation of constraints with some range of uncertainty will be presented. The approach is based on joint chance constrained and fuzzy programming, which addresses the problem of including risk directly in the optimization. Therefore, the stochastic nature of inputs is incorporated directly in the model through the use of convolution of random variables. Furthermore, probabilistic/vague constraints and preassigned tolerance levels are used to transform the stochastic optimization problem into its deterministic equivalent. The approach searches for a control strategy, which maximizes the benefits acquired from hydropower generation and minimizes the economic losses incurred due to not meeting the required reliability levels from the various purposes served by the reservoir system. Besides the optimal reservoir release strategy, this approach also determines the optimal reliabilities of satisfying hydropower demand and flood control storage requirements. Therefore, this tool has some advantages in planning the operations of reservoirs in extreme hydrological events such as floods and droughts. The system is applied to the Wuyang small hydropower plants cascade in the People’s Republic of China

    Switching LPV Controllers for a Variable Speed Pitch Regulated Wind Turbine

    Get PDF
    This paper deals with the control of a variable speed, pitch regulated wind turbine in the whole plant operating area. The wind turbine operating area can be divided into several zones, depending on the wind speed, and the control objectives are different for each operating zone. An hybrid control system composed by several LPV controllers which switches during transitions from one operating area to another is designed in order to ensure asymptotic stability and a good level of performances in the whole operating area. The LPV controllers are calculated from a convex LMI formulation of the problem in order to minimize an H2=HÂĽ criteria that optimizes the energy conversion of the system and that reduces the mechanical fatigue of the plant mechanical structure. The proposed controller is finally compared with two more conventional ones

    Assessment of the key aroma compounds in rose-based products

    Get PDF
    AbstractIn this study, headspace solid phase microextraction–gas chromatography-mass spectrometry and GC-olfactometry were used to analyze the key aroma compounds in three types of rose-based products, including low-temperature extracts (LTEs), high-temperature extracts (HTEs), and rose drinks (RDs). In combination with the Guadagni theory, it was confirmed that the key aroma components of LTE were β-phenyl ethyl alcohol, citronellol, geraniol, and eugenol. The main aroma compounds in HTE were β-phenyl ethyl alcohol, citronellol, geraniol, eugenol, linalool, and rose oxide. The four key aroma compounds in RDs were β-phenyl ethyl alcohol, eugenol, geraniol, and linalool
    • …
    corecore