154 research outputs found

    Morphological Dependence of Star Formation Properties for the Galaxies in the Merging Galaxy Cluster A2255

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    The merging cluster of galaxies A2255 is covered by the Sloan Digital Sky Survey (SDSS) survey. In this paper we perform a morphological classification on the basis of the SDSS imaging and spectral data, and investigate the morphological dependence of the star formation rates (SFRs) for these member galaxies. As we expect, a tight correlation between the normalized SFR by stellar mass (SFR/M_*) and the Hα\alpha equivalent width is found for the late-type galaxies in A2255. The correlation of SFR/M_* with the continuum break strength at 4000 \AA is also confirmed. The SFR/M_* - M_* correlation is found for both the early- and late-type galaxies, indicating that the star formation activity tends to be suppressed when the assembled stellar mass M_*) increases, and this correlation is tighter and steeper for the late-type cluster galaxies. Compared with the mass range of field spiral galaxies, only two massive late-type galaxies with M>1011_*>10^{11} M_{\odot} are survived in A2255, suggesting that the gas disks of massive spiral galaxies could have been tidally stripped during cluster formation. Additionally, the SFR variation with the projected radial distance are found to be heavily dependent upon galaxy morphology: the early-type galaxies have a very weak inner decrease in SFR/M_*, while the inner late-type galaxies tend to have higher SFR/M_* values than the outer late-types. This may suggest that the galaxy-scale turbulence stimulated by the merging of subclusters might have played different roles on early- and late-type galaxies, which leads to a suppression of the star formation activity for E/S0 galaxies and a SFR enhancement for spiral and irregular galaxies.Comment: 21 pages, including 7 EPS figures and 1 tables, uses aastex.cls, Accepted by the A

    A Study on High-Speed Rail Pricing Strategy in the Context of Modes Competition

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    High-speed rail (HSR) has developed rapidly in China over the recent years, for the less pollution, faster speed, comfort, and safety. However, there is still an issue on how to improve the seat occupancy rates for some HSR lines. This research analyzes the pricing strategy for HSR in Wuhan-Guangzhou corridor based on the competition among different transport modes with the aim of improving occupancy rates. It starts with the theoretical analysis of relationship between market share and ticket fare, and then disaggregate choice models with nested structure based on stated preference (SP) data are established to obtain the market share of HSR under specific ticket fare. Finally, a pricing strategy is proposed to improve the occupancy rates for Wuhan-Guangzhou HSR. The results confirm that a pricing strategy with floating fare should be accepted to improve the profit of HSR; to be specific, the ticket fare should be set in lower level on weekdays and higher level on holidays

    Advances in nanomaterial-based targeted drug delivery systems

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    Nanomaterial-based drug delivery systems (NBDDS) are widely used to improve the safety and therapeutic efficacy of encapsulated drugs due to their unique physicochemical and biological properties. By combining therapeutic drugs with nanoparticles using rational targeting pathways, nano-targeted delivery systems were created to overcome the main drawbacks of conventional drug treatment, including insufficient stability and solubility, lack of transmembrane transport, short circulation time, and undesirable toxic effects. Herein, we reviewed the recent developments in different targeting design strategies and therapeutic approaches employing various nanomaterial-based systems. We also discussed the challenges and perspectives of smart systems in precisely targeting different intravascular and extravascular diseases

    Effects of the root extract of Dipsacus asperoides (Caprifoliaceae) on locomotor function and inflammation following spinal cord injury in rats

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    Purpose: The study was performed to determine the effect of Dipsacus asperoides (roots), commonly known as Xu Duan, on rats with spinal cord injury (SCI).Methods: All the animals were separated into 3 groups: normal control; a group that received Dipsacus asperoides treatment after spinal injury, and a group that received phosphate-buffered saline after SCI. These groups allowed for determination of the effect of Dipsacus asperoides treatment on SCI-injured rats. Evaluation of locomotor function restoration based on Basso–Beattie–Bresnahan score was carried out while expressions of I-kBα and NF-kB p65 were estimated. Evaluation of pro-apoptotic protein Bax and anti-apoptotic protein Bcl-2 levels was also carried by Western blotting and densitometry.Results: The results showed that 10-mg/kg/day dose of Dipsacus asperoides restored locomotor function in rats after a period of 4 weeks. The treatment also decreased expressions of I-kBα, NF-kB p65 and Bax, but significantly increased expression of Bcl-2 (p < 0.01) in treated rats, compared to untreated rats.Conclusion: The results indicate that treatment with Dipsacus asperoides extract effectively mitigates spinal cord injury by attenuating inflammation and apoptosis in SCI rats.Keywords: Spinal cord injury, IKK-NFkB pathway, Bax, Bcl-2, Xu Duan, Apoptosi

    Characterization of a thermostable β-glucosidase from Aspergillus fumigatus Z5, and its functional expression in Pichia pastoris X33

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    <p>Abstract</p> <p>Background</p> <p>Recently, the increased demand of energy has strongly stimulated the research on the conversion of lignocellulosic biomass into reducing sugars for the subsequent production, and β-glucosidases have been the focus because of their important roles in a variety fundamental biological processes and the synthesis of useful β-glucosides. Although the β-glucosidases of different sources have been investigated, the amount of β-glucosidases are insufficient for effective conversion of cellulose. The goal of this work was to search for new resources of β-glucosidases, which was thermostable and with high catalytic efficiency.</p> <p>Results</p> <p>In this study, a thermostable native β-glucosidase (nBgl3), which is secreted by the lignocellulose-decomposing fungus <it>Aspergillus fumigatus </it>Z5, was purified to electrophoretic homogeneity. Internal sequences of nBgl3 were obtained by LC-MS/MS, and its encoding gene, <it>bgl3</it>, was cloned based on the peptide sequences obtained from the LC-MS/MS results. <it>bgl</it>3 contains an open reading frame (ORF) of 2622 bp and encodes a protein with a predicted molecular weight of 91.47 kDa; amino acid sequence analysis of the deduced protein indicated that nBgl3 is a member of the glycoside hydrolase family 3. A recombinant β-glucosidase (rBgl3) was obtained by the functional expression of <it>bgl</it>3 in <it>Pichia pastoris </it>X33. Several biochemical properties of purified nBgl3 and rBgl3 were determined - both enzymes showed optimal activity at pH 6.0 and 60°C, and they were stable for a pH range of 4-7 and a temperature range of 50 to 70°C. Of the substrates tested, nBgl3 and rBgl3 displayed the highest activity toward 4-Nitrophenyl-β-D-glucopyranoside (pNPG), with specific activities of 103.5 ± 7.1 and 101.7 ± 5.2 U mg<sup>-1</sup>, respectively. However, these enzymes were inactive toward carboxymethyl cellulose, lactose and xylan.</p> <p>Conclusions</p> <p>An native β-glucosidase nBgl3 was purified to electrophoretic homogeneity from the crude extract of <it>A. fumigatus </it>Z5. The gene <it>bgl</it>3 was cloned based on the internal sequences of nBgl3 obtained from the LC-MS/MS results, and the gene <it>bgl3 </it>was expressed in <it>Pichia pastoris </it>X33. The results of various biochemical properties of two enzymes including specific activity, pH stability, thermostability, and kinetic properties (Km and Vmax) indicated that they had no significant differences.</p

    Real-time scheduling of renewable power systems through planning-based reinforcement learning

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    The growing renewable energy sources have posed significant challenges to traditional power scheduling. It is difficult for operators to obtain accurate day-ahead forecasts of renewable generation, thereby requiring the future scheduling system to make real-time scheduling decisions aligning with ultra-short-term forecasts. Restricted by the computation speed, traditional optimization-based methods can not solve this problem. Recent developments in reinforcement learning (RL) have demonstrated the potential to solve this challenge. However, the existing RL methods are inadequate in terms of constraint complexity, algorithm performance, and environment fidelity. We are the first to propose a systematic solution based on the state-of-the-art reinforcement learning algorithm and the real power grid environment. The proposed approach enables planning and finer time resolution adjustments of power generators, including unit commitment and economic dispatch, thus increasing the grid's ability to admit more renewable energy. The well-trained scheduling agent significantly reduces renewable curtailment and load shedding, which are issues arising from traditional scheduling's reliance on inaccurate day-ahead forecasts. High-frequency control decisions exploit the existing units' flexibility, reducing the power grid's dependence on hardware transformations and saving investment and operating costs, as demonstrated in experimental results. This research exhibits the potential of reinforcement learning in promoting low-carbon and intelligent power systems and represents a solid step toward sustainable electricity generation.Comment: 12 pages, 7 figure

    Effects of carbohydrate drinks ingestion on executive function in athletes: a systematic review and meta-analysis

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    BackgroundCarbohydrates are often used as boosters for endurance and high-intensity exercise. However, it is unclear whether carbohydrate drinks intake before or during exercise can affect specific domains of cognitive function, such as Executive Function (EF).MethodsFollowing the guidance of PRISMA 2020, we searched six major databases including PubMed, WOS, SPORTDiscus, Cochrane, Embase, and Scopus. Outcomes were presented in the form of Reaction Time (RT), Accuracy (ACC), and Scores (Score) for performing EF tests. Effect sizes were calculated from the test results of EF and expressed as standardized mean differences (SMDs). After analyzing the overall results, we performed subgroup analyses based on the athletes’ program characteristics.ResultsAfter retrieving a total of 5,355 articles, ten randomized controlled trials (RCTs) were identified and included in this review. The overall results showed that the intake of carbohydrate drinks before or during exercise did not have a significant effect on the reduction of EF after exercise (ACC (−0.05 [−0.27, 0.18]); RT (−0.18 [−0.45, 0.09]); Score (0.24 [−0.20, 0.68])). The subgroup analyses based on open skill sports and close skill sports also showed invalid results, but the results of RT ended up with different preference (ACC of open skill sports athletes (−0.10 [−0.34, 0.14]); RT of open skill athletes (−0.27 [−0.60, 0.07]); RT of close skill athletes (0.29 [−0.24, 0.82])).ConclusionThe intake of 6–12% of single or mixed carbohydrates before or during exercise was not significantly effective in reducing the decline in EF after exercise. Our findings may have been influenced by the type of intervention, dose, mode of administration, or individual variability of the included subjects
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