63 research outputs found

    Hadronization via Recombination

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    The recombination model as a model for hadronization from a quark-gluon plasma has been recently revived since it has advantages in explaining several important features of the final state produced in heavy-ion collisions at RHIC, such as the constituent quark number scaling of the elliptic coefficient versus the transverse energy of identified hadrons, the bending shape of the pTp_T spectrum of hadrons near 5 GeV/c, and the measured large value of baryon to meson ratio(of the order of unity) in the same pTp_T range. We have developed a dynamic simulation model of heavy-ion collisions in which a quark-gluon plasma, starting from a certain initial condition, evolves hydrodynamically until it reaches the phase boundary, and then hadronizes by valence quark recombination. Rescattering after hadronization is described by UrQMD. We discuss some details of the model and report first, preliminary results.Comment: 6 pages, 3 figures, plenary talk at SQM2008 Conference(Beijing, China, Oct 6-10,2008

    Self-assembly of Ni–Fe layered double hydroxide at room temperature for oxygen evolution reaction

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    Active and stable electrocatalysts are the key to water electrolysis for hydrogen production. This paper reports a facile direct growth method to synthesize NiFe-layered double hydroxides (LDHs) on nickel foil as an electrocatalyst for the oxygen evolution reaction. The NiFe-LDH is synthesized by a galvanic process at room temperature without any additional energy for synthesis. The synthesized NiFe-LDH is a karst landform with abundant active sites and efficient mass diffusion. The NiFe-LDH with an oxygen defect show excellent electrocatalytic performance for the OER, with a low overpotential (272 mV at 10 mA/cm2), a small Tafel slope (43 mV/dec), and superior durability. Direct growth synthesis provide excellent electrical conductivity as well as strong bonding between the catalyst layer and the substrate. In addition, this synthesis process is simple to apply in the fabrication of a large size electrode and is believed to be applicable to commercialized alkaline water electrolysis

    Lattice study of "f0_{0}(600) or σ\sigma"

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    We investigate the propagator of "f0_{0}(600) or the σ\sigma" by the full-QCD simulation with Wilson fermions. We calculate the mesonic correlator in the I=0, JP=0+J^P=0^{+} channel on the 83×168^{3} \times 16 lattice. Plaquet action and Wilson fermion action are adopted. A coupling constant β\beta is set to 4.8 and three kinds of hopping parameter, κ\kappa=0.1846, 0.1874 and 0.1891 are assayed. The disconnected diagram in the propagator is evaluated through taking average over 500 or 1000 Z2 noise. Simulations with the larger hopping parameter provide us with less noisy results. Though the statistics is not yet enough, our results indicate the existence of a pole with a mass in almost the same order as that of the ρ\rho.Comment: Talk given at 20th International Symposium on Lattice Field Theory (LATTICE 2002), Boston, Massachusetts, 24-29 Jun 200

    Lattice Study of Low-lying Nonet Scalar Mesons in Quenched Approximation

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    Using lattice QCD simulation in the quenched approximation, we study the κ\kappa meson, which is ^3P_0 in the quark model, and compare experimental and other lattice data. The κ\kappa is the lowest scalar meson with strangeness and constitutes the scalar nonet. The obtained mass is much higher than the recent experimental value, and therefore the κ(800)\kappa(800) is difficult to consider as a simple two-body constituent-quark structure, and may have another unconventional structure.Comment: 11pages, 5figure

    Scalar Particles in Lattice QCD

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    We report a project to study scalar particles by lattice QCD simulations. After a brief introduction of the current situation of lattice study of the sigma meson, we describe our numerical simulations of scalar mesons, σ\sigma and κ\kappa. We observe a low sigma mass, mπ<mσmρm_\pi<m_\sigma\le m_\rho, for which the disconnected diagram plays an important role. For the kappa meson, we obtain higher mass than the experimental value, i.e., mκ2mKm_\kappa\sim 2m_{K^*}.Comment: 4 figures, to be published in Proceedings of `International Symposium on Hadron Spectroscopy, Chiral Symmetry and Relativistic Description of Bound Systems' (in a series of KEK proceedings

    Cell-permeable peptide nucleic acid antisense oligonucleotide platform targeting human betacoronaviruses

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    IntroductionAntisense oligonucleotides (ASOs) with therapeutic potential have recently been reported to target the SARS-CoV-2 genome. Peptide nucleic acids (PNAs)-based ASOs have been regarded as promising drug candidates, but intracellular delivery has been a significant obstacle. Here, we present novel modified PNAs, termed OPNAs, with excellent cell permeability that disrupt the RNA genome of SARS-CoV-2 and HCoV-OC43 by introducing cationic lipid moiety onto the nucleobase of PNA oligomer backbone.MethodsHCT-8 cells and Caco-2 cells were treated with 1 μM antisense OPNAs at the time of viral challenge and the Viral RNA levels were measured by RT-qPCR three days post infection.ResultsNSP 14 targeting OPNA 5 and 11, reduced the viral titer to a half and OPNA 530, 531 and 533 lowered viral gene expression levels to less than 50% of control by targeting the 5’ UTR region. Several modifications (oligo size and position, etc.) were introduced to enhance the efficacy of selected OPNAs. Improved OPNAs exhibited a dose-dependent reduction in viral replication and nucleoprotein (NP) protein. When a mixture of oligomers was applied to infected cells, viral titer and NP levels decreased by more than eightfold.DiscussionIn this study, we have developed a modified PNA ASO platform with exceptional chemical stability, high binding affinity, and cellular permeability. These findings indicate that OPNAs are a promising platform for the development of antivirals to combat future pandemic viral infections that do not require a carrier

    The total antioxidant content of more than 3100 foods, beverages, spices, herbs and supplements used worldwide

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    Background: A plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies. Methods: We procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table. Results: The results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values. Conclusions: This database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet
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